The structure of Tvrđa and its buildings date back to the Middle Ages. Tvrđa represents the Old Town of the city of Osijek and the best-preserved and largest ensemble of Baroque buildings in Croatia. After the withdrawal of the Ottomans in 1687, during the 18th century, the Austro-Hungarian administration systematically formed a new fortification system, regulated streets and squares and built a large number of military objects. Tvrđa took its present form in the 19th century and has kept it since then. Investigating the historical development of individual buildings, in addition to archival sources and existing architectural documentation, the obvious source of information are the buildings themselves. The aim of this paper is to explore the possibilities of using infrared thermography to find structural elements and hidden openings in historic buildings in Osijek’s Tvrđa. This paper describes the exploration of the 18th century openings on the facades of the former Kostić houses. The facades were bricked into the walls in the 19th century because houses were reused and their purposes changed from commercial to residential. Infrared thermography is often a starting, nondestructive testing method (NDT) for building analyses. This paper presents thermographic analyses of two buildings. The analyses were carried out in December 2017 and January 2018. Using a steady-state thermographic analysis of a building envelope as the first step, the audit was continued with step heating (SH) of an interest point where changes in a thermal pattern were expected due to additional bricking. Heat flux was generated by the usage of a heat gun for paint removal.

The purpose of this research was to analyze the applicability of infrared thermography in assessing the condition of an e-bike battery. The main challenge was to interpret the surface radiation detected by a thermal imaging camera. In addition to basic challenges of thermography, such as determining the emissivity, the angle of image acquisition, the problem of low resolution and thermal inertia, it was necessary to understand the physical behavior of the elements inside the battery and battery pack that respectively determine the dynamics and shape of the thermal pattern. E-bike batteries are mainly composed of 18650 format Li-ion cells, and the topology of the battery cell is related to the energy profile of the system. With the aim of establishing a link between the surface radiation patterns and the parameters of the individual 18650 cells that dictate the internal thermal behavior, a detailed analysis of the battery pack interior, upon its lifetime, was performed. Based on the results of the capacity analysis of the individual cells and determination of the exact position of the cells within the structure of the battery, a visualization and comparison with the thermographic records were performed to determine whether infrared thermography is able to diversify faulty cells. The conclusion of the study is that it is not possible to make a judgment about the thermal pattern expression or the pattern shape based on the estimated capacity values; however, based on the pattern, it is possible to draw a conclusion about the homogeneity of the capacity of the individual battery cells.

Under dynamic load, passive hybrid battery supercapacitor systems (HBSSs) have numerous advantages compared to stand-alone battery systems (SABS). The highlighted benefits include a lower voltage drop at the HBSS terminals, lower current and thermal stress on the battery, and higher energy efficiency. A novel set of analytical expressions is introduced for the analysis of energy efficiency of the passive HBSS in relation to the SABS. Using these expressions, energy efficiency of the passive HBSS was analyzed for different dynamic load parameters. Compared to existing approaches, the proposed approach that uses the introduced analytical expressions provides a better insight into the impact of battery and supercapacitor parameters on the energy efficiency of the passive HBSS in relation to the SABS. Additionally, the proposed approach is suitable for quick determination of HBSS behavior and energy efficiency under dynamic load. This contributes to the advancement of the sizing of HBSS components and optimization practices, ultimately leading to improved energy use. The analysis showed that in cases where the dynamic component of the load current is a very small part of the total load current, or slowly varying load currents, the passive HBSS in relation to the SABS has no advantages in terms of energy efficiency. The analysis showed that the HBSS is more suitable than the SABS in applications where the dynamic component of the load current is significant. The findings also indicate that there is an interval of the battery and supercapacitor parameters which is optimal for the sizing of the passive HBSS from a techno-economic aspect.