A Novel Method for Tooth Bending Stress Calculation of Gears With Asymmetric Teeth

Today, gear designs with asymmetric tooth profiles offer essential solutions in reducing tooth root stresses of gears. Although numerical, analytical, and experimental studies are carried out to calculate the bending stresses in gears with asymmetric tooth profiles a standard or a simplified equation or empirical statement has not been encountered in the literature. In this study, a novel bending stress calculation procedure for gears with asymmetric tooth profiles is developed using both the DIN3990 standard and the finite element method. The bending stresses of gears with symmetrical profile were determined by the developed finite element model and was verified by comparing the results with the DIN 3990 standard. Using the verified finite element model, by changing the drive side pressure angle between 20° and 30° and the number of teeth between 18 and 100, 66 different cases were examined and the bending stresses in gears with asymmetric profile were determined. As a result of the analysis, a new asymmetric factor was derived. By adding the obtained asymmetric factor to the DIN 3390 formula, a new equation has been derived to be used in tooth bending stresses of gears with asymmetric profile. Thanks to this equation, designers will be able to calculate tooth bending stresses with high precision in gears with asymmetric tooth profile without the need for finite element analysis.

Adaptive Control for Pure-Feedback Nonlinear Systems Preceded by Asymmetric Hysteresis

An adaptive control scheme is proposed for a class of uncertain pure-feedback nonlinear systems preceded by asymmetric hysteresis nonlinearity. The asymmetric property is described by the modified Bouc-Wen model based on the proposed asymmetric factor. State variables in the controller design are directly replaced with nonaffine functions to address the control problem caused by nonaffine appearance. Moreover, the control method can handle systems with external disturbances and guarantee the global stability of all the signals in the closed-loop system. The feasibility of the control scheme is verified by a simulation example and experimental results.

Double asymmetric percolation drives a quadruple transition in sexual contact networks

Since 2007, ZIKV outbreaks have been occurring around the world. While ZIKV is mainly spread by mosquito vectors, transmission via sex activities enables the virus to spread in regions without mosquito vectors. Modeling the patterns of ZIKV outbreak in these regions remain challenging. We consider age as an asymmetric factor in transmitting ZIKV, in addition to gender as seen in previous literature, and modify the graph structure for better modeling of such patterns. We derived our results by both solving the underlying differential equations and simulation on population graph. Based on a double asymmetric percolation process on sexual contact networks. we discovered a quadruple ZIKV epidemic transition. Moreover, we explored the double asymmetric percolation on scale-free networks. Our work provides more insight into the ZIKV transmission dynamics through sexual contact networks, which may potentially provide better public health control and prevention means in a ZIKV outbreak.

EFFECT OF CARRIER GAS FLOW RATE AND COLUMN TEMPERATURE ON THE SUITABILITY PARAMETERS OF GC-ECD FOR SF6 MEASUREMENT

System suitability testing of a GC is essential to verify its suitability for intended application. The GC always uses a carrier gas and column temperature, which may impact on its suitability parameters. This study is aimed to evaluate the effects of carrier gas flow rate (FLRT) and column temperature (CLTP) on the system suitability parameters (SSP) of GC-ECD for SF6 measurement such as retention time/tR, response factor/RF, theoretical plate numbers/N, and asymmetric factor/As. The evaluation was conducted by carefully profiling the SF6 chromatogram and the data obtained were used to calculate the tR, RF, N, and As values. It was found that the tR increases linearly (R2 = 0.9978) by increasing the FLRT, but decreases linearly (R2 = 0.9991) by increasing the CLTP. The RF decreases linearly (R2 = 0.9939) by increasing the FLRT. Interestingly, the RF was affected by the CLTP with 2nd polynomial order trend (R2 = 0.9949). The N increases linearly (R2 = 0.9404) by increasing the FLRT but the N was affected b the CLTP with 2nd polynomial order trend (R2 = 0.9769). The As was found to increase slightly with FLRT (R2 = 0.1288), while the As was affected by the CT with 2nd polynomial order trend (R2 = 0.9778). These results are in a good agreement with previous SSP studies.

Springing and Ringing Response of Offshore Triceratops

This paper presents a numerical study of ringing and springing response of a relatively new Offshore Triceratops. The platform is subjected to irregular waves using JONSWAP spectrum by varying the significant wave height, average wave period, vertical asymmetric factor and the over shoot parameter. Strongly asymmetric waves, which are capable of causing impact loads on triceratops, are used to simulate ringing in offshore triceratops. Heave response shows bursts but there are no rapid built ups. Gradual decay, which is seen in the present case, resembles a beat phenomenon.