The paper presents the software application designed to monitor the car parking occupancy rate. The real situations that can be encountered in a parking lot are simulated with the help of a scale model made based on the Raspberry Pi 3 development board. This board connects the existing hardware components on the scale model, the created software applications, and the Cloud Firebase database. The services offered by Firebase use the real-time database and the authentication service. The first is used to store data received from parking sensors and the second to register and authenticate car parking users. The user interface is made within the Android Studio programming environment. The developed applications are the followings: new user account registration, user authentication, parking space reservation, parking entrance, parking space occupation and parking exit. The smart car parking collects real-time information which contributes to diminish the time spent in traffic, decreases pollution, and why not, significantly reduces of the stress of the drivers.

Keywords: smart car parking, Cloud Firebase, Android Studio, Raspberry Pi 3 Board

During the last decades, ion exchange materials technology has evolved from laboratory to industrial use with significant technical and commercial impact. The goal of this paper is to briefly review the ion exchange technologies used for nitrate removal from water intended for human consumption. The following information will be provided: a brief history of ion exchangers, design considerations, process considerations, advantages, disadvantages, process performance, costs and examples of water treatment plants across the Globe that use ion exchangers technology for nitrate reduction. Also, the experimental results regarding the influence of competitive ions on the nitrogen ion retention efficiency on a specialized ion exchange resin will be presented.

Keywords: Ion exchange, Nitrates, water treatment, Pollution

The use of heat pumps to solve energy issues in the field of thermal utilities in buildings is increasingly recommended and necessary

Keywords: heat pump, correlation, energy issue

Generatoarele sincrone cu magneti permanenti sunt esentiale in buna functionare a lantului de conversie a energiei regenerabile – eoliene, de aceea sunt subliniate tipurile de geometrii constructive ale rotoarelor acestora. Lucrarea de fata este un studiu bibliografic care vine in sprijinul producatorilor de top ai centralelor eoliene, pentru a usura munca acestora de proiectare. Un rol important al GSMP este dat de magneti permanenti din pamanturi rare care asigură o cantitate ridicata de energie magnetica necesara functionari excelente a GSMP, ceea ce ii recomanda producatorilor de centrale eoliene.

Synchronous generators with permanent magnets are essential in the good functioning of the renewable energy - wind energy conversion chain that is why the types of constructive geometries of their rotors are highlighted. The present work is a bibliographic study that supports the top manufacturers of wind power plants, in order to facilitate their design work. An important role of the SGPM is given by permanent magnets from rare earths that provide a high amount of magnetic energy required for excellent functions of the SGPM, which is recommended for wind power plant manufacturers.

Spuma de sticla fabricata din deseu de sticla si solutie apoasa de silicat de sodiu (apa de sticla) cu excelente proprietati termoizolante (densitate intre 0,25-0,33 g cm-3, conductivitate termica intre 0,059-0,069 W (mK)-1, porozitate intre 84,3-88,1 % ) pentru aplicatii in constructii a fost realizata cu succes folosind o tehnica originala de incalzire cu microunde predominant directa aplicata de autori, spre deosebire de metodele conventionale utilizate in mod obisnuit la fabricarea spumei de sticla. Lucrarea a testat utilizarea apei de sticla ca agent de spumare in conditiile particulare ale incalzirii cu microunde, desi capacitatea sa este cunoscuta doar ca material de anvelopare in procesele de spumare cu agent carbonic lichid.

Cuvinte cheie: spuma de sticla, incalzire cu microunde, apa de sticla, solutie apoasa alcalina

Glass foam made of glass waste and aqueous sodium silicate solution (water glass) with excellent thermal insulation properties (density between 0.25-0.33 g cm-3, heat conductivity between 0.059-0.069 W (mK)-1, porosity between 84.3 -88.1 %) for building application was successfully performed using an original predominantly direct microwave heating technique applied by the authors, unlike the conventional methods commonly used in glass foam manufacturing. The paper tested the use of water glass as a foaming agent under the particular conditions of microwave heating, although its ability is known only as an enveloping material in foaming processes with liquid carbonaceous agent.

Keywords: glass foam, microwave heating, water glass, aqueous alkaline solution, thermal insulation properties