ABSTRACT Visibility degradation has become one of the major problems of public concern in Kaohsiung City as well as in most of the urban areas of Taiwan in recent years due to the increasing severity of smog. This study investigated the different aspects of atmospheric visibility degradation problems in metro Kaohsiung. First of all, both the long-term and short-term variation trends of atmospheric visibility were interpreted by analyzing the past data of prevailing visibility. Secondly, the correlation of atmospheric visibility with its major causative factors (i.e. meteorological and pollutant parameters) was established. Thirdly, the relationship between visibility degradation and aerosol mass/composition was derived by using multiple linear regression techniques based on in-situ field measurements of ambient aerosols and light extinction coefficient. Finally, the effective strategies for improving the visual air quality of metro Kaohsiung were proposed based on the results of the receptor-oriented modeling. In metro Kaohsiung, the seasonal variation of atmospheric visibility from the highest to the lowest were found to be in the sequence of summer, spring, autumn and winter, with mean values of 9.1, 8.2, 5.4, and 3.4 km, respectively. A diurnal variation of visibility was observed and showed that the visibility was generally lower in the morning and higher in the afternoon. A mass light scattering efficiency of 3.6 m2 g-1 for PM2.5 and a much lower value (0.3 m2 g-1) for PM2.5-10 indicated that the visible light was mainly scattered by the fine aerosol particles. The derived multiple linear regression model of light scattering coefficient yielded the mass scattering efficiencies of 4.6 m2 g-1 for (NH4)2SO4, 6.7 m2 g-1 for NH4NO3, 3.3 m2 g-1 for total carbon, and 3.2 m2 g-1 for PM2.5-remainder with an R2 of 0.97. On average, the percentage contributions of the visibility-degrading species to the light scattering coefficient were 29% for sulfates, 28% for nitrates, 22% for total carbon, and 21% for PM2.5-remainder, respectively. Furthermore, the major component of light extinction coefficient (bext) was the scattering of light by particles (75% of bext), followed by the absorption of light by particles (20%), while the remaining 5% of bext was attributed to gases. An empirical regression model of visibility based on sulfates, nitrates, PM2.5-remainder, and relative humidity was developed. The results showed that the variation of sulfate in PM2.5 aerosols was most sensitive to visibility change among the parameters. In terms of visibility degradation sources, source apportionment results indicated that the major contributors to fine particles were motor vehicle exhaust and secondary aerosols, which contributed more than half of the visibility degradation in metro Kaohsiung. Meanwhile, the second largest contributor was secondary aerosols containing ammonium sulfate and ammonium nitrate. Additionally, the contribution of soil dust increased markedly from normally only 4% to 25%, owing to an impact of continental dust storm from Mainland China. The results strongly indicated that soil dust blown from the desert areas of Northern China could be transported across the Yellow Sea and the East China Sea and evidently deposited in metro Kaohsiung. Results of the correlation analysis between atmospheric visibility and emission sources revealed a similarity between the source contribution pattern for visibility impairment and the source apportionment of fine particles. It showed ammonium sulfate contributed approximately 46% of the logarithm of atmospheric visibility, while the ¡§remainders¡¨, ammonium nitrate, and elemental carbons contributed about 20%, 17%, and 17%, respectively. Accordingly, this study concluded that the most effective strategy for improving atmospheric visibility in metro Kaohsiung was to prevent the formation of secondary fine particles containing ammonium sulfate and ammonium nitrate.

In this study, visibility observation, aerosol sampling, statistical analysis and model regression were conducted to investigate the influence of suspended particle characteristics and pollution sources on visibility and extinction coefficient in Koahsiung metropolitan area. The scene monitored by a digital camera was then proceeded by digital image processing and were then compared with observed atmospheric visibility observation. Meteorological parameters of various weather patterns (including relative humidity, wind direction, wind speed and mixing height ) played important roles on the reduction of visibility in metropolitan area. Synoptic charts were collected over the 1992-1999 period to analyze their influence on ambient air quality. This study revealed that high PM10 concentration and unhealthful PSI index occurred at weather patterns of high pressure outflow style I and circus-sluice of high pressure outflow¡C Regular visibility was observed during the period of November 1998- April 2000. The highest visibility was above 20 km while the lowest visibility was loss than 1 km in Koahsiung metropolitan area. The observed visibility was mainly distribution over the 2-6 km. The visibility below 6 km were about 61.88% of total observation days and poor visibility was usually occurred in winter. Besides, intensive visibility observation was conducted in January and March, 2000. Visibility was observed hourly at Kaohsiung Meteorological Station and Fa-Shin Temple, respectively. Suspended particles were continuously sampled for five hours at Chien-Chen, Sen-Min and Chien-Gin ambient air quality stations. These measurements were conducted to investigate the influence of chemical and physical properties of suspended particle and meteorological parameters on visibility and extinction coefficient in Koahsiung metropolitan area. Receptor model was applied to understand the emission sources of fine particles (PM2.5) and investigate the influence of emission sources on visual air quality. In addition, the determination of visibility by imagine processing was discussed. Visibility observation was coincided with scene monitoring in order to clarify the relationship between image processing and observed visibility. A illumination eigenvalue calculated by picture transfer software was used to correlate with observed visibility. This study revealed that, illumination eigenvalue and observed visibility had strong negative correlation (R=-0.9079) at effective visual range of 5-10 km. Results form single-factor analysis indicated that no significant variation of aerosol particle concentration was observed at three ambient air quality stations. A bi-mode size distribution of aerosol particles was observed for most stations in Koahsiung metropolitan area. The peak aerodynamic diameter of fine and coarse particles was observed at 0.56-1.0

<p>This thesis project describes how the retrieval of aerosol extinction and backscatter coefficients is computed from data obtained with a Raman lidar at FOI, Swedish Defense Research Agency. The theory is described, the implementation is done and problems discovered along the way are discussed. The lidar use the wavelength 355 nm and the Raman shift in nitrogen at 387 nm.</p><p>The retrieved algorithm gives extinction coefficient between 1 500 and 10 000 meters while the backscatter coefficient covers the span 800 to 15 000 meters. However there is skewness in the backscatter coefficient that needs to be further investigated. Tests indicate that the skewness comes from the way the measurements are done at FOI.</p>

This thesis project describes how the retrieval of aerosol extinction and backscatter coefficients is computed from data obtained with a Raman lidar at FOI, Swedish Defense Research Agency. The theory is described, the implementation is done and problems discovered along the way are discussed. The lidar use the wavelength 355 nm and the Raman shift in nitrogen at 387 nm. The retrieved algorithm gives extinction coefficient between 1 500 and 10 000 meters while the backscatter coefficient covers the span 800 to 15 000 meters. However there is skewness in the backscatter coefficient that needs to be further investigated. Tests indicate that the skewness comes from the way the measurements are done at FOI.

In order to make thermal solar power compete with the traditional sources of energy, the efficiency must increase and one way of doing it is by changing the operating fluid. Among the alternate fluids is the use of molten salts as a part of the process; either for thermal storage and later utilization for electrical production during the hours without sun or as a substitute of the operating fluid to provide higher temperatures resulting in better efficiency. The difficulty of using molten salts is the lack of physical properties in literature; such as viscosity, boiling point, vapor pressure and volumetric absorption of solar radiation, thus making the selection of a suitable salt a very difficult endeavor. As a part of the Multidisciplinary Research Initiative (MURI) of the Department of Energy in the project of High Operating Fluids, this work will focus on the optical properties of the molten salts (volumetric absorption). The objective of this Thesis is to design, build and test a device capable of measuring the light attenuation coefficient; which is directly related to volumetric absorption of solar radiation, as well as determine the attenuation coefficient of various eutectic systems for the ternary salt mixture of ZnCl2, NaCl and KCl. Based on the little existent literature, a device capable of measuring the attenuation coefficient was designed, built, validated and tested. This was done by projecting a stable beam of light simulating sun radiation through the molten salt sample and to a spectrometer with a wavelength range going from 400 nm to 1000 nm with operating temperatures going from 350oC to 600oC. This device is capable of controlling the thickness, from 1 to 60 mm, of the molten salt sample by a computer controlled linear stage with an accuracy of 0.1mm. Quartz was used as a container for the molten salts because of its high melting point and transparency. A ceramic heater was used as a heat source, which can heat up the sample to temperatures up to 1200 oC if necessary. Two validation tests for the device were done by measuring the light attenuation coefficient of clear water and extra virgin olive oil and then they were compared to the ones in literature. The eutectic systems were tested next; the results characterized the attenuation coefficient as a function of wavelength and temperature, something that no other experimental work has done before for this specific fluid. These values will help to determine an optimal operating fluid for high temperature thermal applications.

Monomeric red fluorescent proteins (RFPs) are used extensively for applications in molecular biology research, and are especially suited for whole body imaging applications due to their longer excitation and emission wavelengths, which are less damaging and penetrate deeper into animal tissue. However, these proteins suffer from reduced brightness compared to other fluorescent proteins, and require further engineering, which is often achieved through random methods, incurring large time and resource costs. Here we propose a rational design approach to improve the quantum yield of RFPs by reducing conformational variability of the chromophore. We engineered mRojoA, a mutant containing a π-stack involving Tyr197 and the chromophore phenolate, to include the P63F/H/Y mutations on its other side, by simultaneously mutating neighbouring positions 16, 143, and 163. The brightest mutants that we found in each library, mRojo-VYGV, mRojo-VFAV, and mRojo-VHSV, exhibited 1.8- to 2.4-fold increases in brightness, and quantum yield increases of up to 2.1-fold. In all three mutants, the increases in brightness were predominantly due to improvements in the quantum yield and not the extinction coefficient. Solving the crystal structures of two of these mutants along with a dim variant allowed us to strongly infer a link between rigidity of the chromophore and increased quantum yield. In addition, back-mutating position 63 in the highest quantum yield mutant, mRojo-VYGV, reversed the improvement in quantum yield, indicating that Y63 was the primary residue responsible for the improved brightness of the protein. Unfortunately, the mCherry-VYGV mutant did not achieve a similar increase in quantum yield or brightness. This is likely due to the lack of a second bulky aromatic residue at position 197, which is present in mRojoA. Nevertheless, this rational approach could be applied to some other RFPs whose chromophores exhibit increased conformational variability in order to further improve their brightness.

In this study, the weather impact on lidar signals has been researched. A lidar system was placed with a target at approximately 90 m and has together with a weather station collected data for about a year before this study. By using the raw detector data from the lidar, the full waveform can be obtained and the amplitude of the return pulse can be calculated. Atmospheric attenuation of lidar signals is often modeled using the lidar equation, which predicts an exponential decrease in energy over the distance. The factor in the exponent is referred to as the extinction coefficient and it is the main property studied in this thesis. By utilizing models for the extinction coefficient under different weather conditions, it is possible to simulate the performance of the lidar.  The extinction coefficient was calculated using different empirical models. The empirical models investigated in this thesis are the Kim and Kruse models for known visibility, the Al Naboulsi model for different types of fog with known visibility, the Carbonneau model for known precipitation amount in rainy conditions, and a similar model for snowy conditions. For the case of rain, a physical model was also used, which is derived through Mie theory. The physical model requires a particle size distribution, which is the number of particles of a certain radius per unit volume. A particle size distribution for rain was generated using the Ulbrich raindrop size distribution, using the precipitation amount recorded by the weather station. Particle size distributions for radiation and advection fog were also simulated.  The measured attenuation in lidar signals was compared to the predicted attenuation that was calculated using different models for the extinction coefficient in the lidar equation. Generally, the models tend to underestimate the amplitude of the return pulse. This can partially be explained by the assumptions used to derive the lidar equation, which neglects all augmentation of the beam. The visibility models gave more accurate results compared to the precipitation models. This was expected, since visibility is defined as a measure of attenuation and precipitation amount is not.  When a lidar signal is emitted, the light will be reflected from optical surfaces within the lidar and cause a pulse to be detected. This pulse is referred to as the zeropulse. In the first couple of meters of the transmission, we expect to see some backscattered light from adverse weather, since the detector has a larger solid angle at shorter distances. This returned light will be combined with the zeropulse and cause it to expand in width. By examining the zeropulse, it was possible to observe a difference between the average zeropulse under some different weather conditions. This leads to the conclusion that it may be possible to extract some information about current weather conditions from the zeropulse data, given that there is little ambient light and snowy weather conditions.  By integrating the zeropulse, variations in the shape of the zeropulse could be described by a single value. Then by separating the data into low and high visibility populations, the zeropulse integral could be used to predict the visibility. The conclusion was that the zeropulse integral can accurately predict whether visibility is above or below a threshold value, given that there is little ambient light and the visibility is known to be below 19950 m.

Despite its extremely low solubility in water, fullerite C₆₀ can form colloidally stable aqueous suspensions containing nanoscale C₆₀ particles (nC₆₀) when it is subject to contact with water. nC₆₀ is the primary fullerene form following its release to the environment. The aim of the present study was to provide fundamental insights into the properties and environmental impacts of nC₆₀. nC₆₀ suspensions containing negatively charged and heterogeneous nanoparticles were produced via extended mixing in the presence and absence of citrate and other carboxylates. These low-molecular weight acids were employed as simple surrogates of natural organic matter. The properties of nC₆₀ were characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), and UV-Vis spectroscopy. nC₆₀ produced in the presence of carboxylate differs from that produced in water alone (aq/nC₆₀) with respect to surface charge, average particle size, interfacial properties, and UV-Vis spectroscopic characteristics. Importantly, regularly shaped (spheres, triangles, squares, and nano-rods) nC₆₀ nanoparticles were observed in carboxylate solutions, but not in water alone. This observation indicates that a carboxylate-mediated 'bottom-up' process occurs in the presence of carboxylates. Changes in the UV-Vis spectra over time indicate that reactions between C₆₀ and water or other constituents in water never stop, potentially leading to significant morphologic changes during storage or as a result of simple dilution. These results suggest that studies examining the transport, fate, and environmental impacts of nC₆₀ should take the constituents of natural waters into consideration and that careful examination on the properties of the tested nC₆₀ should be conducted prior to and during each study. / Ph. D.

ABSTRACT INVESTIGATION OF LIGHT ATTENUATION IN LAKE EYMIR Selen ATIKER M.Sc, Department of Environmental Engineering Supervisor: Assoc. Prof. Dr. Ayseg&uuml / l Aksoy Co-Supervisor: Assoc. Prof. Dr. Selim Sanin January 2012, 164 pages. Light penetration and attenuation has significant impact on the water quality of lakes. Algal activity, which is important for the levels of several water quality parameters, is dependent on light penetration besides availability of nutrients. In this study, change in light penetration and attenuation in Lake Eymir was studied. The relationships of extinction coefficient (ke), and water quality parameters were investigated. The effect of ke on Chl-a over nutrients were investigated. The water quality parameters measured were / total suspended solid (TSS), phosphate, ammonium, nitrate, photosynthetically active radiation (PAR), chlorophyll-a (Chl-a), Secchi disk depth and lake Depth. The measurements were conducted at five different stations in Lake Eymir. Secchi disk, PAR and lake depth measurements were done on site, while TSS, Chl-a and phosphate analyses were done in laboratory, using standard methods. Nitrate and ammonium analyses were conducted through laboratory kits. Linear and non-linear regression models of ke and Chl-a were developed to understand their relationships with the the measured parameters, using XLSTAT software. Analyses of the data at sampling stations revealed that Station 2 and 3 were the most representative stations in general. The model results indicated that ke is as important as nutrients for Chl-a abundance. Secchi disk and Chl-a are the most correlated parameters with ke. Moreover Secchi disk depth is nonlinearly correlated with ke, while linearly correlation is present between Chl-a and ke. &emsp

To predict the performance of an electro-optical sensor system (EO-system) requires taking the weather situation into consideration. The possibility to use weather data from satellites instead of ground – and flight stations has been investigated. Nearly 170 satellites (about 10% of the functional satellites in orbit) were found to have atmosphere and weather monitoring. A method to select satellite data has been created based on three criteria: (1) the satellite should have a least one payload that measure a weather parameter for EO-system, (2) it should be possible to download data, free of charge, from the specified payload and (3) the satellite should cover geographical areas of interest for a potential user. The investigated performance property is the range, which is affected by many weather parameters, and focus has been on aerosols. The mean value for the aerosol extinction coefficient, for day- and nighttime conditions in December 2016, from the satellite CALIPSO’s lidar instrument Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) has been downloaded from www.earthdata.nasa.gov and implemented in a new developed application to predict the range for an EO-system. In the satellite data, from December 2016, it could be seen that the presence of aerosols, on a global scale, appears below 5 km and that the concentration of aerosols for nighttime condition is higher in local areas. For the test wavelength band of 0.9–2.5 µm, the application showed that the aerosol impact reduced the range by nearly 87%, if the EO-system was in a layer with aerosols. The application for the range prediction of EO-systems is on an early stage and need further development, especially its weather and scene parameters, to become a successful tool for a potential user in the future. / Att förutsäga prestandan hos ett elektro-optiskt sensorsystem (EO-system) kräver att man tar hänsyn till bland annat förhållandet i atmosfären. Möjligheten att använda väderdata från satelliter istället för mark- och flygstationer har undersökts. Det hittades nästan 170 satelliter (cirka 10% av de fungerande satelliterna i omloppsbana) med inriktning på atmosfär- och väderövervakning. En metod för att välja ut satellitdata har skapats som baseras på tre kriterier: (1) satelliten ska ha minst ett instrument som mäter en väderparameter för EO-system, (2) man ska, från internet, kunna ladda ner mätdata från det specifika instrumentet och (3) satelliten ska passera över ett område som är av intresse för en potentiell användare. Den prestandaegenskap som har undersökts är räckvidden, som påverkas av flera väderparametrar, där fokus har legat på inverkan från aerosoler. Medelvärdet för extinktionskoefficienten av aerosoler, för dag och natt i december 2016, från satelliten CALIPSO’s lidarinstrument Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) laddades ner från www.earthdata.nasa.gov och användes i en nyutvecklad applikation för att förutsäga räckvidden hos ett EO-system. Från satellitens mätningar i december 2016 kunde man se att förekomsten av aerosoler mestadels befann sig, globalt sett, uppdelat i olika lager under 5 km höjd och att koncentrationen av aerosoler är högre på natten i lokala områden. Applikationens beräkningar visade att förekomsten av aerosoler påverkade räckvidden för exempel våglängdsbandet 0.9–2.5 µm med en försämring upp till 87% när EO-systemet befann sig i ett skikt av aerosoler. Applikationen för att förutsäga räckvidden hos EO-system är i dess begynnelse och kräver vidareutveckling av både väder- och scenparametrar för att det ska bli ett framgångsrikt verktyg.