Identification of 2-d shape parameters for waste brick powders from varying milling methods: A discussion of quantitative image analysis

Quantitative characterisation of morphology and shape parameters of pozzolanic materials, as a fundamental problem of characterisation of pozzolanic materials, has received significant consideration in literature. Thus far, previous research works have not paid much attention to the circularity, roundness and solidity of pozzolanic materials including waste brick powder (WBP). This research makes a significant contribution on identification of circularity, roundness and solidity of WBP particles under milling conditions using quantitative image analysis. In particular, the goal was to interrogate the ball milling treatment variables for generating WBP using scanning electron microscopy (SEM) and image analysis. Under the milling conditions of changing sample masses introduced in ball mill, the average circularity values for the specimens were approximately 0.6 whilst the average solidity values for the specimens were approximately 0.71. Moreover, the average roundness values for the specimens were nearly 0.51. It was shown that the trends of shape parameters of WBP under changing fineness levels were not significant. The values of circularity, solidity and roundness in this study therefore collaborate to support the discoveries of hidden shape characteristics of WBP specimens and can tackle the overall behaviour of cement-based composites containing WBP. Quantitative image analysis was therefore observed to be capable of inheriting detailed information from SEM micrographs and remains one of the most outstanding approaches of generating shape parameters.

Effect of ultrasonic irradiation on morphology and polymorphic transformation of glycine

The polymorphic phase transformation of β-glycine to α-glycine was analyzed in the absence and presence of three different intensities of ultrasonic irradiation in a batch system at 25 °C. The experiments were performed to explore the effects of ultrasonic irradiation and its intensity on phase transformation time, morphology, storage stability, and filtration characteristics. The crystals obtained with and without ultrasound were characterized by X-ray diffraction (XRD). The XRD results showed that the ultrasound tended to reduce the transformation time. According to the scanning electron microscopy (SEM) images, the ultrasound had a significant effect on the crystal morphology. The highest ultrasound power applied yielded more rounded crystals compared to the crystals prepared in the absence of ultrasound. In addition to SEM analysis, detailed crystal shape analysis was performed and shape factors, namely the circularity, elongation, and convexity values, were determined quantitatively to get more information about the morphological changes related to the variations in the size and shape of the end products. From the morphological point of view, the circularity values of the crystals obtained under ultrasound were higher but the elongation values were smaller compared to the crystals obtained in the absence of ultrasound. It was also found that higher ultrasound decreased the length and width of the crystals, and the application of ultrasound increased the aspect ratio value from 0.483 to 0.657.

Quantifying drivers' visual perception to analyze accident-prone locations on two-lane mountain highways

Owing to constrained topography and road geometry, mountainous highways are subjected to frequent traffic accidents, and these crashes have relatively high mortality rates. In middle and high mountains, most roads are two-lane highways. Most two-lane mountain highways are located in rural areas in China, where traffic volume is relatively small; namely, traffic accidents are mainly related to the design of roads, rather than the impact of traffic flow. Previous studies primarily focused on the relationship between actual road geometry and traffic safety. However, some scholars put forward that there was a significant discrepancy between actual and visual perceived information. Drivers greatly depend on what they perceived by their vision to determine driving behavior. Thus, in this paper drivers' visual lane model was established to quantify drivers' visual perception. To further explore drivers' perception of horizontal and vertical alignments, the visual lane model was projected onto horizontal and vertical planes in drivers' vision respectively. The length and curvature of the visual curve were extracted as shape parameters of drivers' visual lane models. Real vehicle driving tests were conducted on typical two-lane mountain highway sections of G318 in Tibet, China. Then the differences of visual perception at black spots and accident-free locations were analyzed and compared. In horizontal and vertical projections of visual lane model, there were 9 shape parameters have significant differences between accident-prone and accident-free locations. A probabilistic neural network (PNN) was formed to identify accident-prone locations on two-lane mountain highways. This study will lay a foundation for the improvement of traffic safety on mountain highways based on the quantification of drivers' visual perception, during the phase of both road design and reconstruction, and can also make a contribution to the automatic driving technique.