Volume 16 (2021): Edizione 3 (September 2021)

In this paper, we show a new approach in math teaching. The thing that makes this method different from the older ones is the way the notions are defined. Thus, we start with a practical problem from Physics, Chemistry, Biology, etc. and we try to get a formula to solve that problem. At a moment, we stop the try, because of a lack of theoretical notion. Then, it follows a paragraph in which we define the mathematical notion that we need to solve the given problem. Some properties of the notion and useful formulas are given. After that, we go back to the practical problem and, using the new defined mathematical notion, we solve the problem. We use this technique to define very important mathematical notions, as: derivatives, Riemann integral and differential equations. With these tools, some important problems from the real life can be solved.

Urban Warming is an increasing problem in the cities, and inadvertently Thermal Comfort has received an increased attention since the last decade. Compared to indoors, the outdoor environment is more complex and there are larger variations in the climatic parameters. The present research is an effort towards evolving “Human ‘Outdoor’ Thermal Comfort Index”, so as to overcome the limitations of prevalent indices such as ‘Physiological Equivalent Temperature’ and ‘Universal Thermal Climate Index’. The present study was carried out at twenty Public Green Spaces, selected on the basis of geographical location, land use pattern, public prominence, topography and physical area; for 12 hours to monitor Climatic Parameters. The Input parameters included Ambient Air Temperature, Relative Humidity, Wind Speed, Intensity of Sunlight, Green-cover Area; and Public Perception which was ascertained at each observatory with the help of a self-designed compact questionnaire survey. Subsequently, this newly designed empirical relationship was employed for establishing the Thermal Comfort Index of various Public Green Spaces of Bengaluru, with ranking.

Pile foundations are a well-established means of transferring axial loads applied by a superstructure to rigid soil layers. However, the geometrical characteristics of piles can induce the appearance of the buckling phenomenon when using this type of foundation. Furthermore, buckling is a very important factor in the design of piles, especially when the upper layers are loose or weak soil. Pile buckling is currently one of the more complicated geotechnical problems that engineers and researchers have to deal with. The aim of this work is to analyze the effects of some geometrical, mechanical or geotechnical parameters into the value of critical buckling load of an axially loaded pile totally embedded in a homogeneous soil. In this study, numerical buckling analysis is investigated by using three dimensional finite element analysis. The buckling load was studied for concrete pile. while the modulus of soil reaction is adopted constantly with depth. The Numerical results of the buckling loads of fully embedded pile that obtained by the finite element method and Davisson method are also compared in this paper.

A study is performed to estimate the critical seismic incidence angle for a nine-story reinforced concrete dual system building, categorized as plan-asymmetric, by considering a combination of two demand parameters, the Maximum Inter-story Drift (MLID) along the height, and the Seismic Vulnerability Index (SVI). The influence of excitation directionality on the response of the building was investigated by nonlinear dynamic analyses, by applying seven scaled bidirectional ground motion records, oriented in eight incidence angles ranging from 0° to 315°, with a 45° increment. The scaling was made for a peak ground acceleration PGA = 0.30g, according to the elastic response spectrum specified for Bucharest by the Romanian seismic code P100-1/2013. From the results, it was found that the most unfavourable response due to a specific seismic excitation may occur at any angle of incidence, which is not necessarily 0° or 90°, and that the response depends not only on the structural configuration, but also on the excitation characteristics. In addition, the influence of the flexible edge (FE) on the structural demand in terms of SVI was studied. The maximum values for SVI were obtained for the most critical angle of incidence, which is the one that has the higher MLID values in the FE for all accelerograms.

Nitrogen is an important nutrient for the survival of all living organisms, as its chemical binding properties allow to create structures from which proteins are built. In nature, nitrogen is found in many forms and its transformation from one form to another is described by the nitrogen cycle. Ammonium is a form of nitrogen that has no direct effects on human health, but its presence in water supply systems may determine bacterial growth in the distribution networks and ultimately can generate degradation of the water quality. Its concentrations in wastewater and water intended for human consumption can be reduced by the biological process of nitrification. The purpose of this paper is to review the equations and the kinetics of the biological nitrification process.