Applied Mechanics and Materials Vol. 771

Abstract: The multipath ultrasonic flow meter using transit time measurement is being widely used for industrial gas flow measurement. Since the AGA report no. 9 has released, the application of this flowmeter in natural gas metering system has become a technical standard. Currently, the commerical multipath ultrasonic flowmeter employs parallel acoustic path arrangement which consists of four, five or six pairs of ultrasonic transducer. This paper discusses an issue on the acoustic path arrangement of multipath ultrasonic flowmeter in an asymmetric flow profile. From this study, the parallel path arrangement gives relatively inconsistent measurement results when the flow velocity profile was asymmetric.

Abstract: An improved rain detection system has been developed using a marine radar. The rain detection system is composed of a Furuno 1932 Mark II marine radar (radar scanner and display units), a radar control circuit, a signal conditioning circuit, an analog to digital converter (ADC), and a computer with a graphical user interface (GUI). The combination of the microcontroller and optocoupler in the radar control circuit was able to replace the omnipad and pushbutton control and it was also employed to activate the radar and the sector blanket mode. The signal conditioning circuit along with the ADC and the clutter removal made the video and navigation signals from the display unit become ADC-counted rain data. By comparing the ADC-counted rain data of the Furuno marine radar with the reflectivity obtained by GMR X Band weather radar, it was found that the Furuno rain detection sensitivity only spans from 30-55 dBZ.

Abstract: Optical plethysmography technology has been used to design and develop a portable device for heart rate sensor. These device, consisting of near-infrared light-emitting diodes (LEDs) and photodetectors, offer a simple means of extraction the heart rate noninvasively on fingertip’s healthy volunteers. The acquisition signal is carried out based on the detection of the absorbance of near-infrared light in blood vessels due to heart’s pump activity. The microcontroller is used as the main component of electronics module. The communication to personal computer (PC) and power supply of device are provided by USB system. The algorithm of Fast Fourier Transform (FFT) in the software was used to generate the spectra of the signal and determine the HR of the obtained signal. The performance of developed device is tested on 10 fingertips of healthy volunteers, aged 19 to 57 years. A Pulse Oximeter commercial was used as gold standard instrument for comparison of results obtained by the designed device. In this paper the correlation analysis was applied to validate the results of both devices. The analysis show that the HR measured is positively correlated. These results show that the correlation between the HR measured by both the designed PPG device and Pulse Oximeter commercial are almost perfectly linear. Thus, the pulse signals gathered by the designed device are accurately believed to be representative of the heart activity of healthy volunteers. The validation method supports that designed device can potentially be developed as a simple, low power, and portable device for the importance of biomedical research (mainly for processing biomedical signal) and clinical practices.

Abstract: The degradation of pollutants in a waste water with the aid of light as an energy source enabler is one of the photocatalysis processes. Because a textile dye dissolved in water is often used to model the waste water, the degradation of color becomes a major variable to indicate the water clarity after the photocatalysis process occured. Therefore, a sensitive instrument to measure the degradation of color is required. This paper reports a simple spectrometer using a photodiode sensor OPT101 and a light emitting diode (LED). The light emitted by the LED passes through the waste water so that its intensity is reduced. Then, the photodiode sensor receives the light with reduced intensity. In order to test the spectrometer performance, a waste water model was prepared by employing a textile dye in water with various concentrations. Curves showing the relationships between concentration and voltage output of the sensor were obtained for different colors of LEDs (white, blue, orange, red and yellow). A microcontroller is used to process the voltage output of the sensor and an LCD then displays the concentration. The results shows that red LEDs has a smallest error with an error of less than 5%.

Abstract: X-rays have been widely used in medical imaging system. CT Scan is one of the important diagnostic equipments in medical field that uses X-rays as a probe. In the latest CT-Scan generation an array of X-ray detector in a gantry is employed. Solid state detector and gas filled detector are currently used. These type of detector have relatively large in physical size. This influenses the size of the machine as well as its performance. In order to obtain an X-ray detector in a small size a phototransistor was exploited. The phototransistor was attached on a fluoroscent screen and arranged in Darlington configuration. The phototransistor in Darlington configuration was calibrated using visible light. The results showed that there was a linear correlation between the phototransistor output (mV) and the light intensity impinging on the phototransistor surface. A fluoroscent material (ZnS:Ag) then attached on the phototransistor surface. They work as an X-ray detector and calibrated using an X-ray beam generated from an X-ray machine. The results also confirmed that there was a linear correlation between the detector output (mV) and the X-ray intensity stricking the detector surface. The active area of the detector was explored by scanning the surface of the detector in vertical as well as in horizontal directions. The effective diameter of the active area of the detector was found to be 2.2 mm.

Abstract: A system to monitor the signal produced by surface plasmon resonance (SPR) has been designed and tested. The built-in sensor consists of a polarized light source having a wave length 840 nm and a built in 128 photodiodes constructed around the maximum SPR angle to detect the reflection light from the gold surface. The signal produced from the diodes is then amplified and digitized. We use 5173 Hz clock to sample the signal generated by the diode array pixel during the reflection process producing SPR signal around the maximum angle. We program Arduino Mega 2560 to process the signals and transfer it using Lab View to present the data versus sampling time. Doing this, we can record the SPR signal versus time, known as the SPR dynamic signal. To test the performance of the system and to know the properties of the SPR signal, we test the system using ethyl alcohol with concentration of 10% (v/v) up to 90% (v/v). The result shows that the system can be used to monitor the dynamics of SPR signal during the reaction process and it indicates the possibility of using the instrument to detect various kinds of SPR signal related to the chemical and or biological process in the samples.

Abstract: Frequency counter is used widely in many electronic and sensor applications. In a resonance sensor system such as Quartz Crystal Microbalance or Surface Acoustic Wave, frequency counter is the main part of the measuring system. Precision, stability, accuracy and compactness of the frequency counter become a fundamental aspect of the development. In a sensor system, a frequency counter is needed to have a precision down to 1 Hz or even better with a sampling rate of one second. Increasing a precision of the counter from 1 Hz to 0.5Hz will result an improvement of the sensor output signal resolution. In this work we have designed a circuit system which is implemented in a single chip device to get a counting of the frequency down to 0.5Hz without suffering the sampling time. To implement such a required system, a CPLD is one of the best options to be used as a device for the frequency counter. In this paper a dual edge frequency counter using CPLD XC2C256 has been successfully developed. The system consists of 2 channels, 26 bits dual edge frequency counter. The system can count a frequency up to 67MHz, which is enough for the many QCM sensor system. By using a high stabile TCXO and calibrated again a rubidium oscillator, the developed system results in a high stability and accuracy. A precision of 0.5Hz with sampling rate of 1 second can be achieved by the developed system.

Abstract: In the early day of environment monitoring, the measurement is generally done through manual measurement from simple and analog instrument which suffer from the drawbacks like poor accuracy, need of human intervention, associated parallax errors and durability. The rapid development in electronic technology has made reliable integration of smart electronic sensors, processor, and communication device capable of monitoring environmental parameters more favorably. A system for ambient air condition monitoring has been developed as described in this paper. It is based on the embedded system, smart electronic sensor, commercial off-the-shelf (COTS) components, and the terminal monitor by the Graphical User Interface (GUI).

Abstract: Water is the main requirement for the agricultural crops. However, improper amount of water can disturb the plant growth. In modern agriculture, this issue can be tackled by providing the appropriate amount of water for the plant. One of the methods is automatic control system based on the type of physical variables, which indicates water needs for plants [1]. Physical variables that are frequently used as an indicator are temperature and soil moisture [2].The automatic control system can also be applied in agricultural areas that have less water availability. This is due to the automatic control system can help saving water and operating costs [3]. Efforts in building optimal and efficient automated control system can be easily done with complete access to information. One way to access the information control system is via wireless communications [3,4]. From some of these challenges an automatic control system will be built on the research for controlling irrigation in telemetry based on temperature and soil moisture.