Key Engineering Materials Vol. 923

Abstract: A temperature stress testing machine (TSTM) was used to investigate effect of cement composition on cracking sensitivity and creep behavior of concrete. Results show that the cracking sensitivity of concrete varied with the ratio of C₃S/C₂S and it is observed that the temperature difference of concrete linearly increased with smaller ratio of C₃S/C₂S. Furthermore, it is also found that concrete with higher ratio of C₃S/C₂S had weaker creep behavior based on the specific creep deduced from results of TSTM.

Abstract: Agricultural product processing technology, especially fruit and vegetable drying technology, has been researched and applied to preserve food. For dragon fruit, vacuum drying technology is being applied to process chips that meet the quality requirements. However, the flow of steam from the lower layers sticking to the upper layers in the drying chamber not only reduces the quality uniformity between the product layers but also increases the drying time. Therefore, in this study, the vacuum drying system integrated with the moisture-dissipating walls was proposed. Moreover, the research also applied the Taguchi method to optimize the drying parameters for moisture content of dried products.

Abstract: The main aim of this paper is to present experimental results concerning the effects of the temperature and velocity of drying air on the flavonoids extraction rate of houttuynia cordata thunb by heat pump dryer under real weather conditions at Ho Chi Minh City, Vietnam. Drying experiments were carried out at the drying air temperature of 35, 40, 45 and 50 °C, and drying air velocity of 1.0, 1.5, 2.0 and 2.5 m/s, respectively. The experimental results showed that the highest amount of flavonoid extraction rate of the houttuynia cordata thunb was 87.525 mg/g corresponding to the drying air temperature of 45 °C and drying air velocity of 2.0 m/s. The aim also involves analyzing the effects of the drying temperature and drying velocity on the drying time, moisture content, and the specific moisture extraction rate (SMER).

Abstract: Whiteness is an attribute of color perception with high brightness and low colorfulness. In this study, the correlation between instrumental measurement and visual assessment of whiteness of 40 optically brightened white samples was investigated under a LED light source of correlated color temperature (CCT) 5000K combined with Wood's UV-A lamp. Due to over exposure of UV radiation, tested samples were outside of CIE limit. In those cases, standard CIE whiteness formula show significant shift in whiteness interval scale. A high correlation was identified between visual assessment and modified Vik-Viková whiteness formula. The investigations have also shown that the existing CIBA plastic whiteness scale needs to be expanded.

Abstract: The mainstream to be achieved in the development of this scientific research was the development of terry towels based on structural engineering concepts, to increase durability and reduce weight. For this purpose, two different studies were conducted. One of them to evaluate the influence of the height of the loop – where the same height of the loop was kept – and the second prep to assess the impact of weight – in this part the produced terry structures presented similar aerial mass. These studies presented allowed a sample range of 14 different terry structures – all of them produced with a 100% cotton yarn (Ne 16), thus eliminating the parameter of influence of the raw material – that have been characterized in terms of mechanical, permeability, absorption, and capillarity properties, and subsequently compared to a standard terry towel (3-pick terry, 18 ends/cm, 411 gsm). Analyzing the study of the influence of the height of the loop it was possible to conclude that some variations can be introduced in terms of aerial mass by the change of weaving parameters, which resulted in aerial mass losses of up to 10% in some of the cases. Regarding the study of the impact of weight, was possible to verify that with a similar aerial mass between structures, the capillary and moisture release properties were increased by 19% and 12%, respectively.