This paper presents a new type of an electromagnetic sensor for nondestructive testing of carbon-fiber-reinforced polymer composites. The sensor utilizes coupled planar spiral inductors operating typically in the range of 10-500 MHz. The method proposed here shows some similarity to the eddy current technique, but as will be shown, the principles of operation are different as the sensitivity to defects is mostly due to the magnetic field components tangential to the surface of a material. It is shown that the method is applicable to 3-D inspection of carbon-fiber-reinforced composites widely employed in the aerospace industry.

A solid-state microwave generators system is considered as an alternative to the magnetron, in order to inject electromagnetic energy into the cavity of a microwave oven for domestic use. Over current devices, the use of solid state technology allows one to control the frequency and phase of the electromagnetic field generated. Considering a simplified cavity with 2 solid state sources, the influence of the electrical parameters on maximum efficiency obtainable in the process of microwave heating is investigated. By varying the frequency, different values of optimal phases and different values of maximum efficiency are detected. Moreover, the procedure is repeated with varying the position of one source port and the influence of geometry on the system performance is evaluated. Our results demonstrate that the ability to control the electrical quantities of a microwave heating process makes it possible to obtain better results in terms of energy efficiency over the current poorly controllable systems.

A new type of an electromagnetic sensor for nondestructive testing of carbon-fiber-reinforced polymer composites, based on coupled planar spiral inductors, is presented. The sensor operates in the range of 10 - 500 MHz, where the largest detectability of buried defects is expected. The new method shows some similarity to the eddy currents technique but the principles of operation are different as the sensitivity to possible defects is mostly due to a magnetic field horizontal to the surface of the material. One of advantages is the applicability of the method to a three-dimensional inspection of the carbon-fiber-reinforced composites.

This paper discusses the use of IoT sensor networks and spatial data mining methods to support the design process in the revitalization of the university campus of the Warsaw University of Technology (WUT) in the spirit of universal design. The aim of the research was to develop a methodology for the use of IoT and edge computing for the acquisition of spatial knowledge based on spatial big data, as well as for the development of an open (geo)information society that shares the responsibility for the process of shaping the spaces of smart cities. The purpose of the article is to verify the hypothesis on whether it is possible to obtain spatial–temporal quantitative data that are useful in the process of designing the space of a university campus using low-cost Internet of Things sensors, i.e., already existing networks of CCTV cameras supported by simple installed beam-crossing sensors. The methodological approach proposed in the article combines two main areas—the use of IT technologies (IoT, big data, spatial data mining) and data-driven design based on analysis of urban space actors’ behavior for participatory revitalization of a university campus. The research method applied involves placing a network of locally communicating heterogeneous IoT sensors in the space of a campus. These sensors collect data on the behavior of urban space actors: people and vehicles. The data collected and the knowledge gained from its analysis are used to discuss the shape of the campus space. The testbed of the developed methodology was the central campus of the WUT (Warsaw University of Technology), which made it possible to analyze the time-varying use of the selected campus spaces and to identify the premises for the revitalization project in accordance with contemporary trends in the design of the space of HEIs (higher education institutions), as well as the needs of the academic community and the residents of the capital. The results are used not only to optimize the process of redesigning the WUT campus, but also to support the process of discussion and activation of the community in the development of deliberative democracy and participatory shaping of space in general.

We have developed an inexpensive computer controlled microwave oscillator system that enables quick and automatic measurements of the complex permittivity with a specific split post dielectric resonator (SPDR). It is based on a phase-locked loop Microwave Voltage Controlled Oscillator intended for the Q-factor and the resonance frequency measurements of SPDR. Multipoint resonance curve fitting procedure allows accurate Q-factor determination. The only external information that is necessary for the complex permittivity determination of a dielectric substrate or a ferroelectric film is the thickness of the sample under test. We compare the complex permittivity measurement results on few dielectric samples employing Vector Network Analyser and our measurements set-up. We also present measurement results of the sheet resistance and resistivity of epitaxial GaN films deposited on sapphire substrates.