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Elementary Heat Transfer
Published in Anthony F. Mills, Heat and Mass Transfer, 2018
An electronic package for an experiment in outer space contains a transistor capsule, which is approximately spherical in shape with a 2 cm diameter. It is contained in an evacuated case with nearly black walls at 30°C. The only significant path for heat loss from the capsule is radiation to the case walls. If the transistor dissipates 300 mW, what will the capsule temperature be if it is (i) bright aluminum and (ii) black anodized aluminum?
A comprehensive study of the second law of thermodynamics for a rotary regenerative heat exchanger with two types of simple and anodized aluminum sheets: an experimental study
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Amirhossein Akbari, Shahriar Kouravand, Saman Pourahmad
The component of the experimental setup is depicted in Figure 1. As it is shown in this figure, the regenerative heat exchanger system includes a matrix, a jet-fan, an inverter to create a specific flow rate, an electromotor and a gearbox to rotate matrix, a heater consisted of nine 1.5 kW electric heaters, and a power supply to provide the required electrical energy for the electromotor. The features of the equipment and measurement tools used in this study are presented in Tables 1 and 2. To avoid thermal loss, the outer wall of the regenerative heat exchanger was covered with glass wool. In addition, both simple and anodized aluminum sheets were used in the manufacturing of this heat exchanger. These sheets were made of 1050 aluminum alloy with a thickness of 0.5 mm and the thickness of anodized layer is 0.2 mm. Also, thermal conductivity for the aluminum 1050 without anodized layer is 222 W/m. K and thermal conductivity for anodized layer on average is 1.12 W/m. K (Lee et al. 2013). To enhance the turbulence level of flow and consequently, increasing the heat transfer rate as well as the thermal efficiency of the heat exchanger, zigzag sheets were used instead of flat sheets in the fabrication of the matrix. Circular cross-section with a diameter of 20 cm was considered for the matrix, which was divided into two parts by a galvanized separator. These two parts were separated from each other and a minimal mixing region was occurred in the matrix between the hot and cold flow. Details and information of the matrix components are represented in Figure 2.
Durability of structural adhesive joints for facade applications exposed to the extended cataplasm test
Published in The Journal of Adhesion, 2019
K. V. Machalická, M. Vokáč, M. Kostelecká, M. Eliášová
Two substrate materials frequently used in facades were selected for the study – aluminium (blank and anodized) and Zn-electroplated steel. Sulphuric acid anodizing is widely used for corrosion protection of aluminium parts of facades. The average thickness of the anodized layer was 15 ± 1 µm (measured by the eddy-current method). The average thickness of the zinc layer in galvanized steel substrates was 14 ± 1 µm, which was measured by the magnetic-inductive method. Both coatings were applied to metal sheets 3 mm in thickness.
Fabrication of an anodized porous alumina relative humidity sensor with improved sensitivity
Published in Instrumentation Science & Technology, 2020
The alumina strip is anodized by proper selection of anodization parameters such as the voltage, concentration of electrolyte, anodization time, and conductivity of the aluminum sample.[14] In this paper, anodization was performed using sulfuric and oxalic acid solutions as the electrolytes. A platinum electrode served as cathode and the aluminum strip served as the anode.