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Accurately structural damage identification remains a significant challenge due to dynamic response fluctuations caused by temperature variations. To address this problem, a novel two-stage damage identification method based on Multi-head Convolutional Neural Network (MCNN) and Improved Beluga Whale Optimization Algorithm (IBWO) is proposed to precisely predict temperatures, localize the damage, and quantify damage severity. First, the MCNN is exploited to forecast the ambient temperature and detect the number of damaged locations. The predicted values are then fed into an iterative optimization process of the IBWO to identify the damage location and severity. Finally, numerical models of simply supported beams and a 3-storey bookshelf structure are employed to verify the effectiveness and robustness of this method under measurement noises. Results demonstrate that the two-stage diagnosis method can accurately identify both single and multiple damages under varying ambient temperatures. The comparison study with two other state-of-the-art methods also demonstrates the superior performance of the two-stage method in damage localization and quantification.

The hot spot temperature (HST) plays a most important role in the insulation life of the transformer. Ambient temperature and environmental variable factors involved in the top oil temperature (TOT) computations in all transformer thermal models affects insulation lifetime either directly or indirectly. The importance of the ambient temperature in transformer's insulation life, a new semi-physically-based model for the estimation of TOT in transformers has been proposed in this paper. The winding hot-spot temperature can be calculated as function of the TOT that can be estimated by using the ambient temperature, wind velocity and solar heat radiation effect and transformer loading measured data. The estimated TOT is compared with measured data of a distribution transformer in operation. The proposed model has been validated using real data gathered from a 100 MVA power transformer. For a semi-physically-based model to be acceptable, it must have the qualities of: adequacy, accuracy and consistency. We assess model adequacy using the scale: prediction R², and plot of residuals against fitted values. To assess model consistency, we use: variance inflation factor (VIF) (which measure multicollinearity), condition number. To assess model accuracy we use mean square error, maximum and minimum error values of semi-physically-based model parameters to the existing model parameters.

This paper investigates the effect of the ambient temperature change on the dynamic interaction between pantograph and catenary (PAC). Thermal expansion/contraction of the components of the overhead contact system (OCS) is considered. Simulation results show that the thermal stress has a much greater influence on the longitudinal positioning of the contact wire than on the horizontal and vertical positioning. When ambient temperature reduces to $-60^{\circ }$ from design temperature of $20^{\circ }$C, the maximum longitudinal displacement of the positioner can reach as high as 301 mm, while the maximum horizontal and vertical displacement of the positioner is within 4mm. The change of ambient temperature results in the uneven tension distribution of the contact wire, especially near the central anchor. With the increase in temperature, the tension of contact wire decreases; vice versa, with the decrease in temperature, the tension of contact wire increases. For nine-span OCS, the tension change caused by ambient temperature change shall not exceed 2%. The variation of ambient temperature also leads to the deterioration of current collection quality. It is shown that a decreasing ambient temperature results in more significant changes in contact force, close to 5%. An increasing ambient temperature environment leads to a higher uplift of pantograph, close to 30%.

Carbon fiber structural batteries, which combine structural and functional properties, have good energy storage capacity while bearing loads have received attention from scholars at home and abroad in recent years as a new type of energy storage device. However, in the process of use, temperature changes will lead to the occurrence of thermal stresses, which may cause structural failure under multiple cycles. In this paper, the thermal-stress coupled model of structural batteries was established first using the temperature and thermal stress models of structural batteries, considering the heat exchange with the external environment of structural batteries. Then based on the coupled model, the thermal stress in the structural battery was simulated and analyzed in COMSOL considering different charge and discharge rates and ambient temperatures of the structural batteries. The results show that: (1) The higher the charging and discharging rates, the higher the temperature of the structural battery, resulting in greater thermal stress. (2) The higher the ambient temperature of the structural battery, the longer its discharge time and the lower the voltage at which discharge terminates, which is beneficial for the electrochemical performance of the battery. But the higher the ambient temperature, the greater the temperature change inside the structural battery, which is not conducive to the mechanical performance of the structural battery. This study can provide reference for the safety analysis of structural batteries in thermal environments.

Tropical countries like India, the ambient temperature reaches to 45–50${}^{\circ }$C in the summer and higher ambient temperature directly impacts the energy required by the household refrigerator. This paper presents an experimental performance of a domestic refrigerator incorporated with a phase change material (PCM)-based condenser in parallel to the conventional wire-and-tube air-cooled condenser for the climatic conditions of India. It is proposed to operate the refrigerator with the PCM-based condenser, while the ambient temperature is higher during the day, otherwise with the air-cooled condenser. Due to large latent heat storage capacity of the PCM, the condenser temperature would not increase significantly. The COP of the PCM-based condenser was 28% higher as compared to air cooled condenser for 60min which reduce to 3% as PCM temperature reached to 33${}^{\circ }$C. The energy consumption is lower by $\sim 15$% in $3^{\frac{1}{2}}$h of refrigerator experimentation with the proposed modification.

The construction quality of grouting sleeve for rebar splicing is a key factor of reliability of assembled precast concrete structure. For this reason, it is essential to understand the impact of curing conditions on the strength development of the grouting sleeve connectors. Six series of specimens with a total of 90 grouting sleeve specimens and 180 grouting samples cured at temperatures of -15, 0, 5, 15, 25, 35°C respectively have been tested at the ages of 1, 4, 7, 14, 28 days. According to the experimental results, the earlystage strength of grouting sleeve specimens is greatly influenced by the ambient temperature, while the 28-day strength is less affected. The relationship between the strength of grouting sleeve connectors and the ambient temperatures is revealed and equations are derived to evaluate the impacts of ambient temperature to the structural performance of the specimens. Suggestions are proposed as guidance to precast concrete construction.