Aerodynamic performance of flying discs

The purpose of this paper is to examine geometrical design influence of various types of flying discs on their flight performance from the aerodynamics perspective. The lift, drag and moment coefficients of the discs were measured experimentally using a wind tunnel. Three types of golf discs and four sets of simpler parametric discs were studied to analyze and isolate the effect of design factors on these aerodynamic characteristics. Full six degree-of-freedom simulations of the discs were performed to visualize their flight trajectories and attitudes. These simulations, combined with the experimental data, provide details on the well-known “S-shaped” ground-path traced by a flying disc. This study reveals two key parameters to evaluate the flight performance of a disc: its coefficient of lift-to-drag ratio (CL/CD) and, more importantly, its coefficient of pitching moment (CM). The latter influences the tendency of the disc to roll from its intended path, and the former influences its throwing distance. The work suggests that to optimize the flight performance of a disc, the magnitudes and gradient of its CM should be minimized and its trim-point shifted from origin, while its CL/CD should be maximized with a flatter peak. In this study, the design parameters and the aerodynamic characteristics of various types of flying discs are analysed, compared and discussed in depth. Recommendations of design improvements to enhance the performance of any flying disc are offered as well

Development of Heavy Metal Potentiostat for Batik Industry

The consumption of reactive dyes in the batik industry has led to a severe concern in monitoring the heavy metal level in wastewater. Due to the necessity of implementing a wastewater monitoring system in the batik factory, a Heavy Metal potentiostat (HMstat) was designed. The main goal of this study is to understand the optimal design concept of the potentiostat function in order to investigate the losses of accuracy in measurement using off-the-shelf devices. Through lab-scale design, the HMstat comprises of an analog potentiostat read-out circuit component (PRCC) and a digital control signal component (CSC). The PRCC is based on easy to use components integrated with a NI-myRIO controller in a CSC. Here, the myRIO was equipped with built-in analog to digital converter (ADC) and digital to analog converter (DAC) components. In this paper, the accuracy test and detection of cadmium(II) (Cd2+) and lead(II) (Pb2+) were conducted using the HMstat. The results were compared with the Rodeostat (an open source potentiostat available on the online market). The accuracy of the HMStat was higher than 95% and within the precision rate of the components used. The HMstat was able to detect Cd2+ and Pb2+ at −0.25 and −0.3 V, respectively. Similar potential peaks were obtained using Rodeostat (Cd2+ at −0.25 V and Pb2+ at −0.3 V)