Abstract:In order to reduce volatile organic compounds (VOCs) in a vehicle and find the solution, this study proposes a new mathematical model and method of quantitative analyzing and tracing VOCs at multi-levels. In the present work, it is the first time to establish a multi-level VOCs mathematical analysis model and tracing method from vehicle parts to a whole vehicle by synthetically considering both the interactive effects of VOCs compositions emitted from different vehicle parts, and the hazard level of each composition of VOCs based on the national standard limits. This study also applies the multi-objective decision method with the triangular fuzzy number semantics definition theory to construct a pairwise comparison matrix for quantitatively analyzing the influence weights of different levels and the combined weights of multi-levels. The proposed VOCs tracing method can not only accurately analyze the contribution sequence of different VOCs compositions to the VOCs in a whole vehicle, but also quantitatively calculate the contribution of each typical vehicle part to the VOCs in a whole vehicle considering the interaction effects of different VOC compositions coming from different parts, and thus providing a more accurate theoretical method for the traceability and control of VOCs in vehicles. The case study shows that the contribution sequence of different VOC compositions is ranked as formaldehyde > acetaldehyde > toluene > xylene > ethylbenzene. The contribution sequence of vehicle parts to the VOCs in a whole vehicle is ranked as front seats > rear seats > carpet > dashboard and ceiling. The case study proves that the contribution of a vehicle part to the VOCs in a whole vehicle is not a simple superposition of all VOCs compositions, and it is the interaction results coming from different vehicle parts.

Abstract:For the field error calibration problems of electronic voltage transformer (EVT) and electronic current transformer (ECT) in smart substation, field calibration methods of EVT and ECT were proposed on the basis of voltage and current comparative methods. The proposed field calibration methods used the communication protocol IEC 61850.Using a 110 kV smart substation as the background, the distribution of EVT and ECT was analysed respectively,and the operation methods of primary devices were described by using the proposed field calibration methods. By studying the working principle of the proposed field calibration methods, the secondary basic principle and working mechanism of the proposed method were studied. Meanwhile, the equivalent mathematical model of EVTs field calibration method was established. The field results not only demonstrate the effectiveness and accuracy of the proposed method, but also show that the tested EVT can be used as 0.2 level power meter transformers and the tested ECT can be used as 0.2S level power meter transformers.

Abstract:Considering the limitations when the handling stability research methods of cars are applied to tractor trailer,a new research method and an improved measure for handling the stability of tractor-semitrailer were proposed.A system dynamic model of tractor-semitrailer including saddle damping parameter was established,and computer simulation was done under S lane-change working conditions.The relative change response characteristics of the tractors motion parameters,such as the rolling angle and lateral a...

Abstract:By means of the method of combining theoretic analysis with mathematic calculation,the mathematic model of medium mills electromechanical twist vibration was established,the whole response of the system in transition process was obtained by the solution

Abstract:The conception of economical life is introduced for the small and middle-sized power transformers (SMSPT). Based on the evaluation of the loss and maintennace costs as well as the reliability worth,a mathematical model is developed for determining the eco