Optimization of Both the Layout of an Array and the Buoy Dimension for Two Types of Arrays

This paper explores optimal configuration of both dimension and layout of Wave Energy Converter (WEC) arrays with full interaction and exact hydrodynamics. Arrays in this research contain devices that operate in heave mode and also devices that operate in pitch mode. The hydrodynamic interaction between buoys in the array is studied and higher q-factors is achieved using optimization. This study includes optimization results for arrays of only heave-mode buoys and hybrid arrays of 2 types of devices that has been mentioned above. Each of the heave-mode arrays contain 3, 5, and 7 buoys respectively while the hybrid arrays have arbitrarily selected configurations of the type of devices for comparison. This simulation uses impedance matching control which provides theoretical maximum level of power. The results indicates it is essential to optimize array layout simultaneously with the dimension of each buoy. Meanwhile, the mode of motion of the devices in an array is a significant factor in designing the array under complex ocean environment, and better performance of the array is achieved when the configuration is selected properly.

Point Estimation with Markers for Effective Mobile Auditory Graphs

While researchers have performed numerous studies to understand the human interpretation of visual graphs in reading, comprehending and interpreting displayed data; visually impaired (VI) students still face many challenges that prevent them from fully benefiting from these graphs in class. In this study, we conducted a test with 20 students to track the work described in studies in an expanded scenario. As we have tried to answer the question as to whether adding multi-reference mapping of sonification to auditory graphs could improve the of point estimation accuracy in non-visual condition. We also emphasize the efficiency of the performance of multi-reference graphs to make them as efficient as mapping using single pitch. Our proposed study improved performance of multi-reference task completion time by having fewer reference note. The results help provide empirical evidence that the multi-reference mode provides more accurate results than the single-pitch mode and confirms that adding contexts to auditory graphs could be used for better comprehension.

Can multiphase dynamic CT angiography provide a better assessment of aortic dissection compared with the standard triphasic protocol?

Background Acute aortic dissection (AD) is a life-threatening medical emergency. It has been debated whether the multiphase dynamic computed tomography angiography (CTA) protocol is superior to the standard triphasic protocol for revealing the characteristics of AD. Purpose To examine two multiphase dynamic protocols, Dynamic four-dimensional (4D) CTA using the shuttle mode and Flash 4D CTA using the high-pitch mode for the assessment of AD and to compare them with the standard triphasic protocol. Material and Methods A total of 54 consecutive patients were randomly and equally assigned to three groups and scanned with a second-generation DSCT scanner. Groups A, B, and C were assessed with the Dynamic 4D CTA in the shuttle mode, the Flash 4D CTA in the high-pitch mode, and the standard triphasic acquisition protocol, respectively. Image quality of all patients was evaluated. The effective radiation dose (ED) was recorded. Results In 54 patients, CTA images could display the true and false lumens, the intimal flap, the entry tear, and branch vessel involvement in the AD. Compared with group C, additional diagnostic information was obtained in groups A and B, including the dynamic enhancement delay between the true and false lumens (A = 18, B = 18); the presence of membrane oscillation (A = 8, B = 14); dynamic ejection of the contrast material from the true lumen into the false lumen (A = 6, B = 7); and the dynamic obstruction of the left renal artery (B = 2). The ED in these three groups was significantly different ( P < 0.05). Conclusion Compared to the standard triphasic protocol, the multiphase dynamic CTA protocol is feasible and is able to reveal additional diagnostic information. Therefore, we recommend using the high-pitch, dual-source multiphase dynamic CTA to assess ADs.

Investigation of Slider Vibrations and Vibration Mode Changes in Helium-Air Gas Mixtures

A numerical model for the simulation of slider vibrations in helium-air gas mixtures has been developed. The physical properties of the helium-air gas mixture, such as density, mean free path and viscosity, were determined to calculate the dynamic flying characteristics of a slider using the CMRR air bearing simulator. Frequency analysis shows that the helium percentage in the gas mixture can shift the second pitch mode of the slider to a higher frequency.

Modelling and Validation of Vehicle Ride Comfort Model

This paper presents the development of a validated seven degrees of freedom (7DOF) of vehicle ride comfort model for a Malaysian made passenger vehicle. The mathematical equations of the ride model, which consists seven degrees of freedom, are represented. Ride test known as pitch mode test was conducted to validate the reliability of the developed simulation model. The test was conducted using a fully instrumented test vehicle where the sensors installed were used to gather information on vehicle’s vertical and pitch motions. The data collected are used to tune certain parameters value in the simulation model, to ensure the developed simulation model can be used to represent the ride dynamics behaviour of the test vehicle. The result shows that the developed simulation model is capable in representing the ride dynamics behaviour of the test vehicle.