1,721,065 research outputs found
Experimental studies and perspectives of semi-active oleodynamic devices for seismic protection of structures
No full textGeneral editors: Roy T. Severn and Rogério Bairra
Experimental studies and perspectives of semi-active oleodynamic devices for seismic protection of structures
No full textGeneral editors: Roy T. Severn and Rogério Bairra
Effects of ice accretion on the aerodynamics of bridge cables
No full textUndesirable wind induced vibrations of bridge cables can occur when atmospheric conditions are such to generate ice accretion. This paper contains the results of an extensive investigation of the effects of ice accretion due to in-cloud icing, on the aerodynamic characteristics of bridge hangers and stay cables. The aim of this paper is twofold; first, it was investigated the ice accretion process and the final shape of the ice accreted; then the aerodynamics of the ice accreted bridge cables was characterized, and related to the ice shape. Different climatic conditions, i.e. combinations of temperature, wind speed and yaw angle of accretion, were reproduced in a climatic wind tunnel, giving rise to different types of accretion. These were chosen such to generate the most common natural ice formations expected to produce bridge cable vibrations. A description of the geometric characteristics of the ice accretions is given in the paper. Only for the bridge hanger case, a short description of the evolution of the ice accretions is given. The aerodynamic force coefficients were then measured with varying yaw angle, angle of attack and wind speed, and are presented and discussed in the paper; these are found to be significantly affected by the characteristics of the ice accretion
Experimental Test of the Design of Dynamic Experiments and Dynamic Response Surface Methodologies: Growth of a Photosynthetic Microorganism
No full textThe design of dynamic experiments (DoDE) and dynamic response surface methodology (DRSM) have been recently applied to accurately model and optimize several types of industrial and pharmaceutical processes. In this work, we apply the above methodologies to the growth of a photosynthetic microorganism, a bioprocess characterized by a high degree of complexity. Compared to conventional bioprocesses involving heterotrophic bacteria, the high adaptability of photosynthetic microorganisms to environmental conditions and the complexity of understanding the effect of light intensity on biomass growth make the development of a thorough knowledge-driven model a difficult task. Based on a predefined experimental design taking into account the effect of light, temperature, and nutrient feeding profiles, we performed a set of dynamic biomass growth experiments, from which we estimated different DRSM models. The best one was then used to predict the behavior of a new set of experiments. We show that through such a model, valuable insights into the process can be gained and that the model is fairly reliable in predicting growth behavior under different experimental conditions
- …
