Taiwan Association of Engineering and Technology Innovation: E-Journals
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Design and Evaluation of a Novel Low Acoustic Impedance-Based PZT Transducer for Detecting the Near-Surface Defects
Get PDFNear-surface defects are one of the most common types of damage occurring in polymer composite materials. Conventional Non-Destructive Testing (NDT) techniques, especially ultrasonic testing, are not always suitable for detecting these types of defect, especially in thin plates. The proposed NDT method in this article employs Low Acoustic Impedance (LAI) characterization. The novelty of LAI technique lies in the transverse resonating of Lead-Zirconate-Titanate (PZT) transducer which shows significant lower effective acoustic impedance compared to thickness - extension mode. The LAI technique eliminates the need for the matching layers and reduces the manufacturing cost consequently. Briefly, the analytical model has been introduced and the fabrication procedure has been discussed in detail. The setup has been evaluated both numerically and experimentally to detect a debonding. The results proved the ability of LAI technique in the detection of defects and, moreover, the approximate geometry of the affected region as well
Impact Damage Detection in Fiberglass Composites Using Low Acoustic Impedance-Based PZT Transducers
Get PDFThe objective of this work is to evaluate the feasibility of detecting damages caused by impacts in fiberglass-epoxy composites using lead-zirconate-titanate (PZT) transducers. Impacts were created by a hammer (unquantified energy) and an automatic impact system (quantified energy) in multiple composite sheets. The mechanism of the damage detection relies on the impedance measurement by a low acoustic impedance (LAI) transducer, which resonates in the radial mode rather than the regular thickness mode. The effect of surface roughness was investigated by using specimens with different quantified surface roughness values. It was shown that the final results are heavily affected by the rough surface and hard boundary conditions. Mainly, we aimed to evaluate the efficiency of low acoustic impedance technique in the damage detection of composites. The tests were carried out in the energy ranges of 10 to 54 joules. The surface of each specimen was gridded with a step size of 5 mm, and the impedance was measured for each location. The final results were normalized using a no-load condition as the reference point. It was shown that the proposed portable and easy-to-use LAI setup could detect the damages qualitatively. The normalized measured impedance was variable, but it showed a significant increase, in some cases as high as 100%, on the impact’s region
On the Wind Reduction Effect of Windbreak Nets in Front of the Simple Greenhouse for Planting Fruits and Vegetables
Get PDFThe island of Taiwan experiences frequent strong winds coming with typhoons in the summer and with northeast monsoons in the winter. The strong winds are hazardous to the structure of a simple greenhouse that is widely used for vegetable and fruit plantation. The damage may reduce agricultural yields. Windbreak netting is a practical procedure for protecting a greenhouse from strong winds. The purpose of this study is to carry on the wind tunnel simulation test of windbreak nets in front of the simple greenhouse. Windbreak nets of densities 50%, 40%, 30% and 20% had a uniform dimension of 10 cm (per unit 1 h) in height and 29.2 cm in width. A windbreak net was tested at tilt angles of 0o, 5o, 10o and 15o. The wind tunnel simulation test is carried on at 10 m/s of reference wind velocity. The wind velocities at different horizontal distances and vertical distances front and behind the windbreak net are measured. The relative wind velocity is calculated. The wind reduction effect at different horizontal distances behind the windbreak net is analyzed and discussed. From the test results, it is known that when the tilt angle of windbreak net is 0o and the height of windbreak net is 1h, the corresponding wind reduction effect of windbreak nets with 20%, 30%, 40% and 50% porosity is 62%, 61%, 59% and 52% respectively at 2h horizontal distance. The corresponding wind reduction effect of windbreak nets with 20%, 30%, 40% and 50% porosity is 46%, 45%, 40% and 32% respectively at 10h horizontal distance. However, the increase of tilt angle of windbreak net does not have much influence on the wind reduction effect
A Research Survey of Electronic Commerce Innovation: Evidence from the Literature
Get PDFThe development of technology has ignited many innovations in business management, especially in the electronic commerce area. The essential example, that is, online stores and online shopping, is a critical evolution and innovation from traditional brick-and-mortar stores to clicks and mortar. Following previous research (Van Oorschot et al.), this present study adopted bibliometric and keyword analysis to review the main characteristics of electronic commerce innovations. Focused on the academic sources, the research data used in this study were searched for and collected from the Web of Science (WoS), a renowned academic database which covers the most influential research journals in electronic commerce. Based on a combination of several keywords related to “innovation” and “electronic commerce,” the keyword search in the WoS was conducted in May 2019. As a result, a total of 334 research articles related to electronic commerce innovations were collected. Derived from the bibliometric analysis, some keywords that were seldom used in the earlier decade (2000-2009), but which rapidly grew in use in the recent decade (2010-2018) were found, including m-commerce, platforms, social commerce, online review, and co-creation. In addition, the top 10 influential articles listed in each of the two decades were identified. The results show some of the research trajectories in EC innovations. In the first decade (2000-2009), the top 10 papers focused on traditional IT adoption, such as self-service technology, enterprise resource planning systems, and the adoption of general attitude-intention theories such as the technology acceptance model. In the recent decade (2010-2018), researchers have shown more diverse interest in innovative EC applications, such as RFID applications, cloud computing, crowdsourcing, etc. Accompanying these EC innovation contexts, in addition to general attitude-intention theories, more theories such as signaling theory, have been adopted
Job Mix Formulation for Bituminous Concrete Grade II Using C# Programming
Get PDFBituminous Concrete mix design is a complex process and different methods are proposed by a number of researchers. Marshall’s method of mix design is one such process, which became very popular among the practitioners in India and elsewhere. SUPERPAVE method of mix design which takes into account climatic and traffic factors for aggregate and binder selection. It has gained its prominence and is observed to be superior to any other well-known mix design processes. Aggregate gradation adopted for the mix design plays a crucial role in the performance of the mix. Many researchers have developed mechanisms to work out Job Mix Formulations (JMF) so as to reach the appropriate aggregate mix in the field.The analytical phase of JMF deals with the method of blending of aggregates from the identified stockpiles in order to fulfill the requirements of gradation as specified by agencies for a given layer of flexible pavements. Methods proposed for aggregate blending includes the graphical methods, trial and error method and optimization techniques. The aim of these techniques is two-fold; the first is to optimize the cost involved in blending from the known unit cost of individual stockpiles; and the other is to fulfill the gradation recommendations of the local agencies and parameters suggested in other methods. In this research, an attempt has been made to develop C# (C-Sharp) application in .NET framework using the sequential search technique to work out the best blend of aggregate particles by ensuring the requirements mentioned in MoRTH’s (Ministry of Road Transport & Highways, India) recommended practice. Bailey’s method and the maximum density line have been recommended in 0.45 power chart and incorporating optimization criteria. Grade II bituminous concrete has been chosen for the research. It was clearly observed that the fine aggregate fraction in the stockpiles influences the final Job Mix Formulation. The devleloped tool can accommodate up to 5 stockpiles. It was also observed that the Bailey’s requirements are more stringent when compared with MoRTH requirements as far as JMF is considered. The developed tool is capable of generating the blends with Recycled Asphalt Pavement (RAP) aggregate blends
Simulation of a 0.6 V Wideband CMOS LNA Design Using Forward Body Bias
Get PDFA 0.6-V wideband Low-Noise Amplifier (LNA) design using a 0.18 μm CMOS standard process is presented in this paper. An important goal for the design is to achieve wideband under a low supply voltage. The presented LNA design is a three-stage amplifier, which is based on a common gate stage and two common source stages. The common gate stage provides a wideband input matching. The two common source stages provide a flat gain. A forward body bias technique is used to reduce the supply voltage of the wideband LNA. The forward body bias, that is, the body-source voltage (VBS) is greater than 0 V, decreases the threshold voltage of the NMOS transistor, achieving the low voltage LNA. The supply voltage that is applied to the wideband LNA is only 0.6 V and the Power Consumption (PDC) is 9.24 mW. Simulation results indicate that the gain exceeds 10 dB and the Noise Figure (NF) is below 6.5 dB from 1.62 GHz to 7.02 GHz. The main advantage of the LNA is it's wideband with a low supply voltage
New Ventures, Internationalization, and Asymmetric Grin Curve: Analysis of Taiwan’s Big Data
Get PDFUnder globalization, small and medium enterprises (SMEs) that predominate Taiwan’s economy have been primarily original equipment manufacturers (OEMs) continuing to adjust operating strategies in order to extend supply chains and enhance competitiveness. This paper adopts the big data composed of 104,377 Taiwanese manufacturers from the 2011 Industry, Commerce, and Service Census to assess impact of the business life cycle, brand revenue, R&D spending, and internationalization on value creation. Major findings are as follows. First, the link of the firm’s operating years with value creation is characterized by a quadratic U-shaped curve where the minimum point corresponds to 15 years of operation, suggesting a cost of lower value added for new ventures at the early stage of development. Second, a reversed U-shaped curve of value creation is found as regards brand revenue and R&D spending, with the greater impact of the latter. Third, the impact of overseas investment and export expansion is also captured by a reversed U-shaped curve, with greater impact for the former. Fourth, an asymmetric grin curve rather than a smile curve is found in Taiwan’s manufacturers, whose value creation can be strengthened by strategies that focus on the learning curve, internationalization, internet, operating scale, and capital intensity
Photovoltaic Power Control Using Fuzzy Logic and Fuzzy Logic Type 2 MPPT Algorithms and Buck Converter
Get PDFThis work presents the analysis, design, simulation and hardware implementation of the classical Fuzzy Logic (FL) and the proposed Fuzzy Logic Type 2 (FLT2) MPPT techniques for standalone PV System. FL and FLT2 MPPT algorithms are simulated via MATLAB/ Simulink and implemented via LabVIEW software and CompactRio hardware, in different climatic conditions. Also, they are compared to the Incremental Conductance (InC) MPPT algorithm, one of the most common used MPPT techniques. The studied system consists of PV array, DC/DC converter, MPPT controller, batteries and load. The PV array is connected to the DC / DC buck converter that works based on the output pulses of the MPPT controller to make the PV system operates at the Maximum Power Point (MPP). Thereafter, based on the simulations and the experimental results, a comparison is made to be useful for MPPT designers and researchers in this area
A Biogas Desulphurization System with Water Scrubbing
Get PDFThe biogas is renewable energy with very good potential. It is a gas produced by the bacteria transformation of the organic substance under the anaerobic condition. It is a flammable gas because it contains the hydrogen sulfide (H2S) in its composition. It will cause damage to metal equipment and the corrosion of the pipe. So before using the biogas, the desulphurization process should be carried on. The purpose of this study was to design a water scrubbing system for biogas and carry on the performance test of the desulphurization process in the hog farm. In the field test, the biogas flow rate is changed in the water scrubbing cylinder and under different external circulation water flow rate. The H2S concentration in the biogas is detected before and after water scrubbing, and the desulphurization efficiency of biogas was discussed, furthermore, the pH value of water in the water storage tank was measured. When the H2S adsorbed by water was at steady state, whether the pH value of external circulation water can meet the effluent standard was discussed. From the test results, it showed that the removal efficiency of H2S was 47.7% in 30 minutes of water scrubbing time under 120 ℓ of total water amount, 80 cm of water level in the water scrubbing cylinder, 20 ℓ/min of internal circulation water flow rate and 10 ℓ/min of external circulation water flow rate, and 25 ℓ/min of biogas flow rate. The pH value of water in the water storage tank was 6.22, which met the effluent standard of regulation for discharging directly. This system can reduce the H2S content in the biogas, and purify the quality of the biogas. The operation of this system is convenient and the fabrication cost is low, which is suitable for the small-scale hog farm to purify the biogas
A Performance Evaluation of Modified Weighted Pathloss Scenario Based on the Cluster Based-PLE for an Indoor Positioning of Wireless Sensor Network
Get PDFThe indoor positioning system is one of the popular topics in the current study; it is mainly due to the inability of the Global Positioning System (GPS) applied inside a building. LANDMARC (Location Identification based on Dynamic Active RFID Calibration) and Enhanced LANDMARC Scenario use calibration RSSI values and weighted process to obtain accuracy of position estimation. Meanwhile, WPL (Weighted Pathloss) method improves the positioning accuracy of the two previous methods (LANDMARC and Enhanced LANDMARC) by observing the Path Loss Exponent (PLE) value in an indoor environment, followed by using the value to estimate the object position. We propose a Modified WPL uses Cluster Based Pathloss Exponent (PLE) method by combining the functions of the existing calibration in LANDMARC Scenario with the Cluster Based PLE value. The test bed was conducted in an indoor area on the 3rd floor of the PENS Postgraduate Building. The nodes were connected to each other using X-Bee Pro S2 module. RSSI (Received Signal Strength Indicator) value was used to estimate the distance between transmitter and receiver nodes. The result of the MSE estimation position using the proposed method was 3.80 meters, whereas WPL method was 5.78 meters. Overall, the proposed Modified WPL with Cluster Based PLE method showed that it had the capability to enhance the accuracy of localization; 34% better than the standard WPL method