The propagation constants (loss and phase) are determined for the normal modes in dielectric‐lined overmoded (guide radius ≫ wavelength) circular guide by numerical solutions of the appropriate characteristic equations. It is shown that the heat loss of the TMpn modes is quite low and decreases with increasing frequency in contrast to the increase in heat loss predicted by the perturbation theory for thin linings. The primary effect of the low‐loss TMpn modes on a transmission system using the TE01 mode is a reduction in the route bend losses.
In this paper we adopt a phenomenological approach in order to develop a suitable Cellular Automata (CA) model capable to satisfactory mimic city growth and urban sprawl. The use of CA in urban expansion modeling is well known since many years, but very rarely it has been related with a down-top approach which considers inhabitants' preferences as a driving tool to characterize the CA algorithm. In addition, we consider as a control mechanism of the cell conversion rate (i.e. the number of cells experiencing conversion into urban use) the logistic function. This function is tuned on the free space (cells) at disposal for the urban development. In this paper we present the basics of the model and we perform a simple simulation in the case of a generic geographic pattern.
In this paper an experimental activity regarding the detection of noise produced by a high velocity train along a "almost" straight railway, and a semi-quantitative theoretical model which gives the shape of trains noise in that running conditions, are described. During this investigation the comparison between software predictions and experimental measurements was focused. At the present stage of our study we are starting with the theoretical reproduction of the time history of the phenomenon. In a previous paper we reported about the same goal referred to low velocity trains with very different operating conditions. So in this work we try to underline differences and similarities.The experimental measurements procedure is based on the detection of the sound level outside a building placed in an interesting position with respect to the rail line. It is some three hundred meters far and in a position from which one can observe more than three kilometres of railway. Measurements were performed by a first class Measuring System.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.