The aim of this study is to find out in which way the education about climate in school is taught and how the students experience the world situation today. There are various theories about the greenhouse effect and its origin and these theories should be addressed to ensure that students get a broader understanding of how climate change occurs. This includes the natural phenomena and also the human impact on climate change. Students in school are a source of concern that only human are the cause of global warming, and know little or almost nothing about the natural phenomena of global warming.  I will mention what has emphasized in the national steering documents in the case of environmental education at school. I have used a qualitative method, where interviews and document analysis were used as techniques. The interviews took place with five students in ninth grade and with three science teachers in the same school.

Metro Kaohsiung with high percentage (6-10 %) of poor air quality (PSI>100) has been announced officially by Taiwan Environmental Protection Administration (TEPA) as the worst air quality region among seven Air Quality Zones (AQZ) in Taiwan. Ozone is one of two major air pollutants that are responsible for the poor air quality. In this study, the vertical concentration profiles of ozone and its precursors (NOX and VOCs) at eight sites were measured by tethered balloons with air pumps and tedlar sampling bags. This method was used to investigate the vertical profile and the tempospatial distribution of ozone and its precursors in offshore/inland regions. This study further investigated ozone formation mechanism and air mass trajectory via simultaneous air quality sampling around the coastal region of metro Kaohsiung. This study sampled the vertical concentration profiles of ozone and its precursors at both inland and offshore sites during eight intensive sampling periods on August 16-17 and November 2-3, 2006, January 24-25, March 6-7 and May 2-3, 2007, October 30-31, 2008, and March 11-12 and July 15-16, 2009. Eight sampling periods were divided into the sea-land breeze period, the northeast monsoon period, and the mixing wind field period. During the sea-land breeze period, the wind direction changed 90˚ and more between daytime and nighttime, and the wind speeds of the sea breezes varied significantly than those of the land breezes. During the northeast monsoon period, prevailing wind blew from the north (300~60˚) with the average wind speeds of 1~4 m/s. During the mixing wind field period, the wind direction varied significantly from 270˚ to 90˚ with the average wind speeds of 1~3 m/s. Results obtained from the vertical profiles showed that O3 concentration appeared stratification phenomenon at 40 out of 64 sampling sites, in which its precursors (NOX or VOCs) demonstrated stratification phenomenon at 30 sampling sites, accounting for 75 % of total O3 stratification. It suggested that ozone and its precursors had strong correlation with each other. The linear slope of the titration effect showed that the intensity of titration effect at night during the northeast monsoon period was larger and had higher correlation (R> 0.7), and followed by the mixing wind field period and the sea-land breeze period. This phenomenon correlated closely with meteorological conditions, the concentrations of O3 precursors, and solar radiation intensity. Therefore, O3 concentration at night during the northeast monsoon period was lower than those of the sea-land breeze period. Results obtained from VOCs measurement indicated that the major species of VOCs was acetone which accounted for 16.25~64.05 % of total TVOCs-C2 in the offshore region. High concentration of TVOCs-C2 was affected by the usage of organic solvents. While, the major species of VOCs in the inland region was toluene which accounted for 6.41~43.77 % of total TVOCs-C2. Furthermore, results obtained from backward trajectory showed that air pollutants emited from land sources could transport to the offshore region, resulting in high concentration of oversea NOX and VOCs. Major species of VOCs for high O3 formation potential were aromatics and vinyls at the height of 0~500 m around the coastal region of metro Kaohsiung. The control of O3 precursors concentration showed that the ratio of [TVOCs-C2]/[NOX] in the offshore region was higher, indicating that O3 formation was NOX-limited. Therefore, NOX must be controlled for reducing O3 formation. However, the ratio of [TVOCs-C2]/[NOX] in the inland region was lower, some cases even below 4, showing that O3 formation was VOCs-limited. Thus, VOCs must be controlled for reducing O3 formation.

Based on the Lyapunov stability theorem, a sliding mode control design methodology is proposed in this thesis for a class of perturbed switched systems. The control of the systems is rest restricted to switching between two different constant values. New sliding mode reaching conditions are proposed for the controllers so that the controlled systems can enter the sliding mode in finite time. Once the switched control system is in the sliding mode, the stability of the system is guaranteed by choosing a suitable sliding surface. In addition, a method for alleviating the infinite switching phenomenon is also provided in this thesis. Finally, a numerical and a practical example with computer simulation results are given for demonstrating the feasibility of the proposed control scheme.

Automotive turbochargers (TCs) increase internal combustion engine power and efficiency in passenger and commercial vehicles. TC rotors are usually supported on floating ring bearings (FRBs) or semi-floating ring bearings (SFRBs), both of which are inexpensive to manufacture. However, fluid film bearings are highly nonlinear components of TC units and contribute to the complex behavior (i.e. bifurcations and frequency jumps between a first whirl frequency and a second whirl frequency) of the entire rotor-bearing system (RBS). The frequency jump phenomenon concerns the TC manufacturing industry due to increased levels of noise generation. This thesis presents progress on assessing the effects of some bearing parameters and operating conditions on the RBS dynamic forced performance and the frequency jump phenomenon. A fluid film bearing model is integrated into a finite element rotordynamics computational model for numerical prediction of the TC linear and nonlinear (time transient) forced response. Since automotive TCs operate with variable rotational speed, predictions are conducted with shaft acceleration/deceleration. Over most of its operating speed range, TC rotor nonlinear response predictions display two subsynchronous whirl frequencies w1 and w 2 representing a conical mode and a cylindrical bending mode, respectively. At low shaft speeds w1 is present up to a shaft speed (Omega bifurcation), where there is a frequency jump from w1 to w 2. The second whirl frequency may persist up to the highest shaft speeds (depending on operating conditions). Results show during rotor deceleration the Omega bifurcation may be different from the one during rotor acceleration (hysteresis). Predictions show the following factors delay the Omega bifurcation: increasing oil supply pressure, decreasing oil supply temperature, and increasing shaft acceleration. Also, rotor imbalance distribution greatly affects Omega bifurcation and the shaft amplitude of total motion. Overall, this study shows the sensitivity of bifurcations and frequency jump phenomenon in TC nonlinear response due to various bearing parameters and operating conditions. Further analysis is required to generalize these findings and to assess the effect of other bearing parameters (i.e. clearances, outer film length, ring rotation, etc.) on this phenomenon. In addition further validation of the predictions against test data is required for refinement of the predictive tool.

Annular gas seal clearances were simulated with closely spaced parallel plates using a Flat?Plate tester. The device is designed to measure the pressure gradient along the test specimen. The main function of the Flat?Plate tester is to provide friction factor data and measure dynamic pressure oscillations. A detailed description of the test facility is described, and a theory for determining the friction factor is reviewed. Three clearances were investigated: 0.635, 0.381, and 0.254 mm. Tests were conducted at three different inlet pressures (84, 70, and 55 bars), producing Reynolds numbers range from 50,000 to 700,000. Three surface configurations were tested including smooth?on-smooth, smooth?on?hole, and hole?on?hole. The Hole?pattern plates are identical with the exception of the hole depth. The results indicate that, for the smooth?on?smooth and smooth?on?hole configurations, the friction factor remains constant or increases slightly with increasing Reynolds numbers. Moreover, the friction factor increases as the clearance between the plates increases. However, the results from the hole?on-hole configurations are quite different. A "friction?factor jump" phenomenon was observed, and the Helmholtz frequency was detected on the frequency spectra.

No description available.

No description available.

Liquid crystal display (LCD) has been widely used as an important human interface with typical portable devices such as notebook-type computers, digital camera and cell phones, etc. The LCD panel does not emit light spontaneously, and thus it needs a surface backlight source. The function of light guide plate (LGP) was to guide light from a light source and radiates it homogeneously from all over its output surface. In this thesis, the research object was focused on this optical component. This thesis mainly concludes two major parts. The first part focused on the design of cold fluorescent lamp (CCFL) light source LGP. If the bottom structure of the LGP in a backlight module was made up of V-Cut micro-structures, then conventionally, the shape and spacing between any two adjacent columns of micro-structure should be designed specifically in order to obtain a more uniform illuminance distribution. It was required to apply complicated mathematics and cost a lot of time to design. In this study, a simplified bottom structure of the LGP was proposed. The considered bottom structure of the LGP was proposed to be made up of same shape high energy V-Cut micro-structures, and the spacing between any two adjacent columns of the micro-structure was also the same. The design parameters were determined by using optimization technique. Also, the LCD design time could be reduced. In order to eliminate the dark region phenomenon caused by the proposed simplified bottom structure of the LGP, a simple new type of edge structure of the LGP was proposed also. The proposed simplified LGP design concepy has many merits, such as only three design parameters needed, manufacturing easily, the design time can be reduced, and can prevent the consumption of light source energy between the gaps of CCFL and LGP. The proposed design concept was applied on the design of 7 inches, 15 inches and 20 inches of backlight module (BLM). Through the numerical simulation by utilizing commercial software Light Tools, it can be shown that more than 80% of uniformity can be easily obtained. The second part focused on traditional dot pattern bottom structures. As the same concept mentioned in the first part, the proposed dot pattern was made up of same geometrival shape of dots, and the spacing between any two adjacent columns of the dots was also the same. The design parameters were determined by using optimization technique. The proposed design concept of the dot patten distribution can be applied on the design of LGP with either LED or CCFL light source. Also, the dark phenomenon did not occur, and so the corresponding edge structure did not need either. The proposed design concept was applied on the design of 7 inches, 15 inches and 20 inches of BLM with CCFL light source and on the design of 7 inches of BLM with LED light sources. The optical simulation results showed that about 90% of uniformity can be easily obtained.

<p>The purpose of this thesis is to examine how a depreciation in the exchange rate affects the trade balance in an economy over time. The outcomes of a depreciation are possible to analyze through the J-curve phenomenon that shows the relation between the exchange rate and the trade balance both in the short-run and the long-run. The data used in this thesis cover 39 countries and their quarterly changes in exchange rate between 1982 and 2005. The largest depreciation for each country during these years was detected and is the base for this research. In this thesis, focus is on the trade ratio rather than the trade balance for empirical purposes. The relation between the largest depreciations and its effect on the trade ratio are examined in two sets of regressions. The results show no evidence of a J-curve in neither one of the sets of regressions, even though the trade ratio is positively affected by the depreciation. When testing only for significantly large depreciations in the exchange rate the affect on the trade ratio is stronger, all else equal. According to the findings in this thesis, a depreciation in the real effective exchange rate causes the trade ratio to increase immediately and then decrease over time. The conclusion is that the findings are not in line with the J-curve phenomenon tested for; however, they support standard trade theory with the Marshall-Lerner condition being met i.e. a depreciation in the exchange rate will affect the trade balance positively.</p>

This thesis investigates near-field wireless power transfer using multiple transmitters or multiple receivers. First, transmitter diversity is investigated in terms of the power transfer efficiency (PTE). It is found that an improvement in the PTE can be achieved by increasing the number of transmitters. Furthermore, a region of constant PTE can be created with the proper arrangement of transmitters. Next, receiver diversity is investigated in detail. An improvement in the PTE can be also achieved by increasing the number of receivers. However, it is shown that when two or more receivers are closely located, the PTE is reduced due to mutual coupling between receivers. This is termed a ‘sink’ phenomenon, and it is investigated through measurement and simulation. Finally, to account for more general situations of multiple transmitters and multiple receivers, Monte-Carlo simulation is applied. The cumulative distribution function (CDF) is used to interpret the results of the Monte-Carlo simulation. The transmitter and receiver diversity gain can be found based on the CDF. Moreover, the sink phenomenon can be observed by analyzing the CDF curve. Several strategies for positioning receivers are introduced to reduce the sink phenomenon. The results of the Monte-Carlo simulation also show that a saturation in the transmitter or receiver gain is reached when the number of transmitters or receivers is increased. Therefore, increasing the number of transmitters or receivers beyond a certain number does not help increase the PTE. / text