Thermal image drift is observed in prevalent industrial-level cameras because their optomechanical design is not optimised to reduce this phenomenon. In this paper, the effect of temperature on industrial-level cameras is investigated, focusing on the thermal image drift resulting from ambient temperature changes and warming-up process. Standard methods for reducing thermal image drift are reviewed, concentrating on the lack of repeatability aspect of this drift. Repeatable thermal image drift is crucial for applying a compensation model as random thermal deformations in sensors cannot be compensated. Moreover, the possible cause of this issue is explored, and novel optomechanical camera modifications are proposed that maintain the thermal degrees of freedom for the deforming sensor, limiting the lack of repeatability aspect of thermal image drift to a low level. The improvement is verified by conducting experiments using a specialised test stand equipped with an invar frame and thermal chamber. Considering the results from the application of the polynomial compensation model, the standard deviation of the central shifts of image drift is reduced by ×3.99, and the absolute range of image drift is reduced by ×2.53.

Magnetic hysteresis occurs in most electrical engineering devices once soft ferromagnetic materials are exposed to relatively high temperatures. According to several scientific studies, magnetic properties are strongly influenced by temperature. The development of models that can accurately describe the thermal effect on ferromagnetic materials is still an issue that inspires researchers. In this paper, the effect of temperature on magnetic hysteresis for ferromagnetic materials is investigated using a self-developed numerical method based on the Preisach distribution function identification. It employs a parameter depending on both temperature and the Curie temperature. This approach is of the macroscopic phenomenological type, where the variation of the magnetization (in direct connection with the Preisach triangle) is related to the observed macroscopic hysteretic behavior. The isotropic character of the material medium is predominant. The technique relies on a few experimental data extracted from the first magnetization curve provided by metallurgists. The ultimate goal is to provide a simple and robust magnetic behavior modeling tool for designers of electrical devices. Temperature is introduced at the stage of identifying the distribution function of the Preisach model. This method is validated by the agreement between the experimental data and the simulation results. The developed method is very accurate and efficient in modeling the hysteresis of ferromagnetic materials in engineering particularly for systems with ferromagnetic components and electromagnetic-thermal coupling.

The non-uniformity of temperature field distribution of long-span steel structure is proportional to the intensity of solar radiation. Based on the background of Guangzhou Baiyun Station large-span complex steel roof structure, this paper studies the non-uniformtemperature field distribution of large-span steel structure under the Summer Solstice daily radiation-thermal-fluid coupling action based on Star-ccm¸ finite element software, and uses Spa2000 software to analyze the stress and deformation of steel roof under temperature action. Combined with the on-site temperature monitoring, the maximum difference with the measured value is 2.5˚C compared with the numerical simulation results, which verifies the validity of the finite element simulation. The results show that: from 8:00, with the increase of solar altitude angle, the intensity of solar radiation increases, the temperature rises, and the temperature distribution of large-span steel structure becomes more and more non-uniform. From14:00 to18:00, the solar radiation weakens, and the temperature distribution tends to be uniform. Finally, reasonable construction suggestions and measures are proposed to reduce the adverse effects of temperature effects, which can provide theoretical references for the safe construction and normal operation of large-span steel structures located in the subtropics.