Taiwan Association of Engineering and Technology Innovation: E-Journals
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Innovative Security Technology for Optical Fiber Data Transmission Using Optical Vortex
Get PDFThis article presents system concept of the use of an optical vortex phenomenon for secure data exchange in the optical fiber line. Optical vortices are obtained in free space, and then they are introduced into the optical fiber. Their properties are examined in the world [1-2], so far, which directly shows the ability to increase the bandwidth of optical fiber. Given the structure and characteristics of the optical vortex, the authors propose to set a secure optical link. Such link can be provided in two ways.The first method involves coding an information on optical vortex. The data in the optical fiber line can be coded by time-position modeling of the optical properties of the vortex. In addition, changing the topology of the optical vortex and the use of mode dependencies also offer the possibility of information coding.The second way to use the vortex in the optical fiber is setting of optical fiber sensor, sensitive to the disturbance of fiber-optic transmission line. It can be achieved by propagation both - coded information in basic mode and an optical vortex in a microstructural fiber. In the case of physical impact on optical fiber the vortex disturbs the flow of data, forming the information noise on the output of the fiber.The article presents the setup of the generation of optical vortex, for the telecommunications bandwidth, developed at the Institute of Optoelectronics, in the Security Systems Group and initial tests of the setu
Angular Velocity Analysis of an Epicyclic Gear Train Using Fundamental Circuits and a Block Diagram
Get PDFThe prediction of angular velocity is a prerequisite to investigate the power flow and mechanical efficiency of an epicyclic gear train. This paper presents a useful tool, which combines the fundamental circuit and a block diagram, to analyze the angular velocity of an epicyclic gear train. It is a visualized and straightforward method without manipulating tedious kinematic equations, which makes the angular velocity analysis of epicyclic gear trains more simplified. A compound epicyclic gear train used in a synchronous differential device is taken as an example to demonstrate the analysis process of the proposed approach. The velocity ratio of the epicyclic gear train is also derived
Numerical Study of the Operation of Motorcycles Covering the Urban Dynamometer Driving Schedule
Get PDFIt is shown, for the most challenging case of a cruiser motorcycle of low weight-specific and displacement-specific power and torque, that the tuning for better top end performances is irrelevant for the operation over the driving schedule used for certification. During the certification test, the engine only operates in the low speeds and loads portion of the map. It is concluded that any statement about motorcycles’ pollution and fuel consumption should be only based on the measurement of their regulated emissions through proper chassis dynamometer tests, possibly redefining the driving schedule to better represent real driving conditions
Traffic Safety Evaluation Based on Vision and Signal Timing Data
Get PDFWith the advancement of recent image processing technologies numerous imaging applications have been developed to collect traffic information. In this study, image processing technology is applied to roadway safety to detect and measure the conflict between pedestrians and vehicular traffic and investigate the correlations between the conflict and signal timing data. By using an image processing technique, pedestrian and vehicular movements are detected and the distance between these two are calculated to detect conflicts between them. In this study, Machine Learning techniques are utilized to facilitate more accurate and efficient detection. It is assumed that the intersection is accident-prone if conflicts between pedestrian and vehicular traffic appear more frequently than other intersections and correlations exist depending on the status of signal timing, for example at the end of green signal for a particular movement. This approach is expected to identify accident-prone intersections without actually experiencing crashes; therefore, this would potentially reduce social costs associated with traffic accidents
Advantages of Multi GNSS Constellation: GDOP Analysis for GPS, GLONASS and Galileo Combinations
Get PDFPositioning techniques made lots of progress in the last decades, thanks to the wide usage of the Global Navigation Satellite Systems (GNSS). During a satellite survey, interruption or complete absence of positioning service can happen due to obstacle presence or constrained environments. To avoid these problems, it is suitable to simulate a positioning survey determining the number of the GNSS satellites in view and their availability trend for a selected location. Using more than one constellation the number of the observed satellites is increased and the continuity and reliability of positioning significantly improved. The aim of this paper is to assess the impact of multi-GNSS constellation on positioning calculation in terms of number of available satellites and geometrical distribution in the sky. A simulation is conducted for different cut-off angles, ranging from 0° to 30°: satellites visibility predictions are performed for the city of Benevento (Italy) using short observing sessions (96 daily) and considering GPS, GLONASS and GALILEO constellation. The benefits of their combinations are investigated: in order to assess the observation quality, the Geometrical Dilution of Precision (GDOP) is used as criteria to prove how it is possible to reduce degradation of the position accuracy by using multi-GNSS combinations. Particularly, GPS+GLONASS supplies higher performances compared to the other solutions. Because the low number of satellites in view, the contribution of GALILEO is limited, and its presence instead of GPS or GLONASS in the two constellation solutions produces a decrease in positioning accuracy
Numerical Modelling of the Operation of a Novel Two Stroke V4 Engine
Get PDFThe paper presents simulations of the operation of a novel two-stroke engine for road Super Sport motorcycles. Two-stroke engines were preferred to four-stroke engines in Grand Prix motorcycle racing until the start of the Moto GP era when new rules phased out the two-stroke engines. Reasons for the change were the poor fuel economy and significant pollutant emissions. The paper discusses the opportunity of a came back at least in road Super Sport motorcycles thanks to the recent advantages in direct injection and precise lubrication for two-stroke engines, plus the opportunity to use jet ignition, based on performance simulations
Assessment of a Charge Transport Model for LDPE through Conduction Current Measurement
Get PDFConduction current measurements have been widely used to characterize charge transport behavior in insulating materials. However, the interpretation of transport mechanisms and more generally of non-linear processes from current measurements alone is not straightforward. For this reason, space charge measurements, on the one hand, and models of charge transport encompassing charge generation, trapping and transport have been developed. The completeness and accuracy of a model can be assessed only if a substantial range of stress conditions, being field and temperature for the current topics, is available. The purpose of this communication is to enrich the investigation of low density polyethylene - LDPE insulation material characteristic using conduction current measurement. Measurements were conducted on 250 μm thick LDPE samples, for DC fields in the range 2 to 50 kV/mm and for temperatures from 20 to 70°C. Experimental data, i.e. transient current in charge/discharge and quasi-steady state currents are compared to the prediction of a bipolar transport model that has been developed over the last years and fitted to the case of LDPE. The deviation of model results is substantial, with essentially an overestimation of the non-linearity of the current-field dependence. These differences are discussed along with prospects from improving the model. Aside from these modelling approaches, we show that thermal preconditioning of samples appears to be influential in the measured apparent conductivity
Simulation of Desiccant Cooling
Get PDFDesiccant cooling system has been an attractive topic for study lately, due to its environmentally friendly nature. It also consume less electricity and capable to be operated without refrigerant. A simulation study was conducted using 1.5 m long ducting equipped with one desiccant wheel, one sensible heat exchanger wheel, one evaporative cooling chamber and two blowers and one electric heater. The simulation study used 8.16 m/s primary air, the drying coefficient from desiccant wheel, k1=2.1 (1/s), mass transfer coefficient in evaporative cooling, k2=1.2 kg vapor/s, heat transfer coefficient in desiccant wheel, h1=4.5 W/m2 oC, and heat transfer coefficient in sensible heat exchanger wheel h2= 4.5 W/m2 oC. The simulation results show that the final temperature before entering into the air conditioning room was 25 oC and RH of 65 %, were in accordance with the Indonesian comfort index
High-temperature Corrosion of T22 Steel in N2/H2S-mixed Gas
Get PDFASTM T22 steel (Fe-2.25Cr-1Mo in wt.%) was corroded at 600 and 700 oC for 5-70 h under an atmospheric pressure that consisted of N2-(0.5. 2.5)%H2S-mixed gas. T22 steel corroded rapidly, forming outer FeS scales and inner (FeS, FeCr2O4)-mixed scale. The formation of the outer FeS scale facilitated the oxidation of Cr to FeCr2O4 in the inner scales. Since the nonprotective FeS scale was present over the whole scale, T22 steel displayed poor corrosion resistance
CAE Analysis of Secondary Shaft Systems in Great Five-axis Turning-Milling Complex CNC Machine
Get PDFThe commercial computer aided engineering (CAE) software is used to analyze the linear-static construction, stress and deformation for the secondary shaft systems in great five-axis turning-milling complex computer numerical control (CNC) machine. It is convenient and always only three dimensional (3D) graphic parts needed firstly prepared and further more detail used for the commercial CAE. It is desirable to predict a deformed position for the cut tool under external pressure loads in the working process of CNC machine. The linear results for static analysis of stresses, displacements in corresponding to the screw shaft locates at top, medium and bottom positions of the secondary shaft systems are obtained by using the simulation module of SOLIDWORKS®