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Bridge managers all over the world are always looking for simple ways to measure bridge vertical displacements for structural health monitoring. However, traditional methods to obtain such data are either tedious or expensive. There is a need to develop a simple, inexpensive, and yet practical method to measure bridge vertical displacements. This paper proposes two methods using either optical fiber (FBG) sensors or a charge-coupled-device (CCD) camera, respectively, for vertical displacement measurements of bridges. The FBG sensor method is based on the measured horizontal strains together with the identified curvature functions obtained by a self-developed FBG Tilt sensor. CCD cameras use a large number of pixels to form an image. The CCD camera method utilizes image processing techniques for pixel identification and subsequent edge detection. A preliminary study to validate the proposed methods in laboratory was presented. The tests include applying the methods to determine the vertical displacements separately for a concrete beam and a steel beam under various loadings. The comparisons include their installations, costs, degrees of accuracy, external factors affecting the measurement, etc. It was concluded that both methods could be used for vertical displacement measurement, and they could be complementary with one another. It was suggested to further improve the two methods developed and a successful outcome will not only help to solve an important problem for bridge management, but also prepare the way for better structural health monitoring techniques.

The demand for high-speed wireless data communication systems is continuously increasing such as 802.11a wireless local area network (WLAN). The development of high integration level and single chip solution for system is desirable to enable implementation at low cost and low power. The fully integrated transceivers of these systems are possible to implement in continuing advance’s complementary metal oxide semiconductor (CMOS) which have allowed low cost of transceiver design in the multi-gigahertz frequency range. Among the building blocks of frequency synthesizer, voltage-controlled oscillator (VCO) is an important block since it significantly affects the system performance of transceiver. Therefore, continuous researches have been motivated to focus on low-power, low phase-noise and high frequency’s fully integrated VCO implementations. In this thesis, two low-power high frequency CMOS LC quadrature voltage-controlled oscillators (QVCOs) have been designed and demonstrated. Both designs are fabricated in 0.13μm CMOS technology. The first one is a 0.8-V CMOS quadtrature LC VCO using capacitive coupling (CC-QVCO). By using capacitors as coupling elements, two LC VCOs are forced to oscillate in quadrature phase in a low power and low phase noise way. Fabricated in a 0.13um CMOS process and operated at 0.8-V supply, the proposed QVCO measures phase noise of -112dBc/Hz at 1M offset from 4.91GHz while drawing a total current of 4mA, which corresponds to a FOM of 181 dB. The core area is 0.278mm2. The Second design is a A 1-V CMOS quadrature LC VCO using diode coupling. By using diode’s reifying characteristic, second harmonic current component is generated the common source of cross-coupled pairs such that lock the two LC VCOs to operate in quadrature mode. At 1-V supply and at 3.9GHz, the QVCO measures phase noise of -117dBc/Hz at 1-MHz offset while dissipating 7.5mA which corresponds to a figure of merit of 180dBc. The core area is 0.37mm2.

Motor vehicle emissions have been identified as the major source of air pollution in most urban cities. They have a serious impact on our urban air quality and public health. In the present study, the vehicle exhaust gaseous and particle emissions from different fuel types of on-road representative vehicles including petrol/gasoline, diesel, and liquefied petroleum gas vehicles for urban driving conditions ranging from 10 to 70 km h-1 were investigated using the chassis dynamometer and remote sensing testing systems. Both testing systems have been widely used for dirty screening/clean screening credit utility programs, and for inspection and maintenance programs. T'he measured vehicle exhaust emission concentrations from both testing systems were further calculated into the average gaseous and particle (i.e., PM0.1, PM2.5, and PM10) emission factors (EFs) in milligrams or grams per kilometer for different urban driving conditions. The results show that the different fuel types of the selected on-road vehicles and their driving conditions have a direct effect on the characterization of vehicle exhaust gaseous and particle emission factors. The correlation equations of the calculated average vehicle emission factors of different size fractionated exhaust particles and hydrocarbons (HCs) in milligrams or grams per kilometer with a good regression coefficient, R2, value from different fuel types of on-road representative vehicles were also established. It is demonstrated clearly that the correlation between EFPM and EFHC is highly sensitive to the different fuel types, engine cylinder sizes and rated powers, and aftertreatment emission control and maintenance conditions of the selected on-road vehicles. The results of the present study can be used for predicting the gaseous and particle pollutants dispersion from on-road vehicles in urban roadway environments. © 2007 American Chemical Society.

In the present study, the real-world on-road liquefied petroleum gas (LPG) vehicle/taxi emissions of carbon monoxide (CO), hydrocarbon (HC) and nitric oxide (NO) were investigated. A regression analysis approach based on the measured LPG vehicle emission data was also used to estimate the on-road LPG vehicle emission factors of CO, HC and NO with respect to the effects of instantaneous vehicle speed and acceleration/deceleration profiles for local urban driving patterns. The results show that the LPG vehicle model years and driving patterns have a strong correlation to their emission factors. A unique correlation of LPG vehicle emission factors (i.e., g km-1 and g l-1) on different model years for urban driving patterns has been established. Finally, a comparison was made between the average LPG, and petrol [Chan, T.L., Ning, Z., Leung, C.W., Cheung, C.S., Hung, W.T., Dong, G., 2004. On-road remote sensing of petrol vehicle emissions measurement and emission factors estimation in Hong Kong. Atmospheric Environment 38, 2055-2066 and 3541] and diesel [Chan, T.L., Ning, Z., 2005. On-road remote sensing of diesel vehicle emissions measurement and emission factors estimation in Hong Kong. Atmospheric Environment 39, 6843-6856] vehicle emission factors. It has shown that the introduction of the replacement of diesel taxis to LPG taxis has alleviated effectively the urban street air pollution. However, it has demonstrated that proper maintenance on the aged LPG taxis should also be taken into consideration. © 2007 Elsevier Ltd. All rights reserved.