Дисертації з теми "Atmospheric sciences not elsewhere classified"
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Faki, Hajira. "The development and evaluation of photo-antimicrobial isoalloxazine dyes towards infection control." Thesis, University of Central Lancashire, 2018. http://clok.uclan.ac.uk/23986/.
Повний текст джерелаStampouli, Dafni. "Improved qualification of vascular abnormalities in contrast enhanced magnetic resonance angiographic images." Thesis, University of Central Lancashire, 2009. http://clok.uclan.ac.uk/19967/.
Повний текст джерелаWodike, Obelema Tonbo Seddon. "Designing a value centred inspection method for children." Thesis, University of Central Lancashire, 2016. http://clok.uclan.ac.uk/16736/.
Повний текст джерелаMcLarnon-Riches, Christian James. "The use of lipid profiles from immobilised Selenastrum capricornutum in the biological surveillance of freshwaters." Thesis, University of Central Lancashire, 2000. http://clok.uclan.ac.uk/19764/.
Повний текст джерелаLu, Chen. "Expression profile of multidrug resistance genes and proteins in cancerous and stem cells." Thesis, University of Central Lancashire, 2008. http://clok.uclan.ac.uk/19754/.
Повний текст джерелаWoodruff, Kim Therese. "The effects of anaesthetic agents on synapses of lymnaea stagnalis (L.)." Thesis, University of Central Lancashire, 2004. http://clok.uclan.ac.uk/20248/.
Повний текст джерелаChandranath, Swaminathan Irwin. "Comparitive activities and mechanisms of action of three novel antiulcer agents." Thesis, University of Central Lancashire, 2000. http://clok.uclan.ac.uk/21028/.
Повний текст джерелаHigginson, James Matthew. "Signal transduction pathways involved in skeletal muscle fibre type regulation." Thesis, University of Central Lancashire, 2003. http://clok.uclan.ac.uk/21870/.
Повний текст джерела(5930444), Ximena V. Yepez. "CHARACTERIZATION AND ANALYSIS OF HIGH VOLTAGE ATMOSPHERIC COLD PLASMA TREATMENT OF SOYBEAN OIL." Thesis, 2020.
Знайти повний текст джерелаFindings presented in this dissertation show that polyunsaturated fatty acids of soybean oil effectively reacted with high voltage atmospheric cold plasma gas species of various gases including hydrogen, nitrogen, and oxygen at room temperature without a catalyst. Hydrogenation, nitration, and epoxidation reactions were observed along with polymerization. Unexpectedly, hydrogen gas was not the primary source of atomic hydrogen observed under these experimental conditions. Rather, it is suggested that water vapor, present as an impurity, supplied hydrogen ions to the hydrogenation reactions. Nitrogen gas modified atmosphere is an electron-rich medium that catalyze reactions. Further investigation is suggested for optimizing the process of oil hydrogenation, as well as for exploring the potential to produce bio-based gels, lubricants, and greases.
(8802641), Tianren Wu. "STUDIES ON AEROSOL SIZE DISTRIBUTIONS, EMISSIONS, AND EXPOSURES." Thesis, 2020.
Знайти повний текст джерелаAerosols are solid or liquid particles that span in size from a few nanometers to tens of micrometers. They are important in both outdoor and indoor environments due to their impact on climate and human health. Many aerosol processes of interest to the environment, health, and filtration are strongly size-dependent. Aerosol particle size distributions (PSDs) provide a basis to better understand outdoor and indoor air pollution sources, evaluate human exposure to air pollution, and aerosol deposition in the human respiratory tract and filters in building ventilation systems. Monitoring the temporal evolution of aerosol PSDs enable for characterization of dynamic aerosol transport and transformation processes, such as direct emissions, nucleation, condensation, coagulation, resuspension, deposition, and filtration. This thesis presents three studies on the PSDs of: (i.) urban aerosols in cities around the world in order to identify geographical trends in the shape and magnitude of PSDs and to frame future research needs for PSD observations at a global-scale, (ii.) synthesized salt particles from a novel thermal aerosol generator to evaluate its suitability for air filter testing, and (iii.) indoor biological particulate matter (bioPM) to characterize transient inhalation exposures of infants and adults to resuspended bioPM from carpet dust induced by crawling and walking.
First, this thesis presents the current state-of-knowledge of urban aerosol PSDs by critically analyzing n=793 urban aerosol PSD observations made between 1998 to 2017 in n=125 cities in n=51 countries across the following regions of the world: Africa (AF), Central, South, and Southeast Asia (CSSA), East Asia (EA), Europe (EU), Latin America (LA), North America, Australia, and New Zealand (NAAN), and West Asia (WA). Prominent geographical variations in the shape and magnitude of urban aerosol number and mass PSDs were identified and significant variations in number PSDs were found between cities in EU and NAAN with those in CSSA and EA. Most PSD observations published in the literature are short-term, with only 14% providing data for longer than six months. There is a paucity of PSDs measured in AF, CSSA, LA, and WA, demonstrating the need for long-term aerosol measurements across wide size ranges in many cities around the globe. Inter-region variations in PSDs have important implications for population exposure, driving large differences in the urban aerosol inhaled deposited dose rate received in each region of the human respiratory system. Similarly, inter-region variations in the shape of PSDs impact the penetration of urban aerosols through filters in building ventilation systems, which serve as an important interface between the outdoor and indoor atmospheres. The results of this critical review demonstrate that global initiatives are urgently needed to develop infrastructure for routine and long-term monitoring of urban aerosol PSDs spanning the nucleation to coarse modes.
Second, this thesis evaluates a newly designed commercially available thermal aerosol generator for ageing air filters in building heating, ventilation, and air-conditioning (HVAC) systems. The physical characteristics of the synthesized salt aerosol (NaCl and KCl) under different generator operational conditions were evaluated. The shape of the number and mass PSD output of the thermal aerosol generator are similar to those found in outdoor (urban) and indoor air and can be modulated by varying the rate at which the salt stick is fed into the flame. The morphology of the NaCl and KCl particles varied with size, with compact spherical or cubic structures observed below 100 nm and agglomerates observed above 100 nm. The thermal aerosol generator is a cost-effective technique for rapid ageing of HVAC filters with a PSD that more accurately represents, compared to conventional loading dusts, what filters encounter in real HVAC installations.
Lastly, this thesis characterizes infant and adult inhalation exposures and respiratory tract deposited dose rates of resuspended bioPM from carpets. Chamber experiments were conducted with a robotic crawling infant and an adult performing a walking sequence. Breathing zone (BZ) size distributions of resuspended fluorescent biological aerosol particles (FBAPs), a bioPM proxy, were monitored in real-time. FBAP exposures were highly transient during periods of locomotion. Both crawling and walking delivered a significant number of resuspended FBAPs to the BZ, with concentrations ranging from 0.5-2 cm-3. Infants and adults are primarily exposed to a unimodal FBAP size distribution between 2 and 6 μm, with infants receiving greater exposures to super-10 μm FBAPs. In just one minute of crawling or walking, 102-103 resuspended FBAPs can deposit in the respiratory tract, with an infant receiving much of their respiratory tract deposited dose in their lower airways. Per kg body mass, an infant will receive nearly four times greater respiratory tract deposited dose of resuspended FBAPs compared to an adult.
(8771531), Licheng Liu. "Quantifying Global Exchanges of Methane and Carbon Monoxide Between Terrestrial Ecosystems and The Atmosphere Using Process-based Biogeochemistry Models." Thesis, 2020.
Знайти повний текст джерелаMethane (CH4) is the second most powerful greenhouse gas (GHG) behind carbon dioxide (CO2), and is able to trap a large amount of long-wave radiation, leading to surface warming. Carbon monoxide (CO) plays an important role in controlling the oxidizing capacity of the atmosphere by reacting with OH radicals that affect atmospheric CH4 dynamics. Terrestrial ecosystems play an important role in determining the amount of these gases into the atmosphere. However, global quantifications of CH4 emissions from wetlands and its sinks from uplands, and CO exchanges between land and the atmosphere are still fraught with large uncertainties, presenting a big challenge to interpret complex atmospheric CH4 dynamics in recent decades. In this dissertation, I apply modeling approaches to estimate the global CH4 and CO exchanges between land ecosystems and the atmosphere and analyze how they respond to contemporary and future climate change.
Firstly, I develop a process-based biogeochemistry model embedded in Terrestrial Ecosystem Model (TEM) to quantify the CO exchange between soils and the atmosphere at the global scale (Chapter 2). Parameterizations were conducted by using the CO in situ data for eleven representative ecosystem types. The model is then extrapolated to global terrestrial ecosystems. Globally soils act as a sink of atmospheric CO. Areas near the equator, Eastern US, Europe and eastern Asia will be the largest sink regions due to their optimum soil moisture and high temperature. The annual global soil net flux of atmospheric CO is primarily controlled by air temperature, soil temperature, SOC and atmospheric CO concentrations, while its monthly variation is mainly determined by air temperature, precipitation, soil temperature and soil moisture.
Secondly, to better quantify the global CH4 emissions from wetlands and their uncertainties, I revise, parameterize and verify a process-based biogeochemical model for methane for various wetland ecosystems (Chapter 3). The model is then extrapolated to the global scale to quantify the uncertainty induced from four different types of uncertainty sources including parameterization, wetland type distribution, wetland area distribution and meteorological input. Spatially, the northeast US and Amazon are two hotspots of CH4 emissions, while consumption hotspots are in the eastern US and eastern China. The relationships between both wetland emissions and upland consumption and El Niño and La Niña events are analyzed. This study highlights the need for more in situ methane flux data, more accurate wetland type and area distribution information to better constrain the model uncertainty.
Thirdly, to further constrain the global wetland CH4 emissions, I develop a predictive model of CH4 emissions using an artificial neural network (ANN) approach and available field observations of CH4 fluxes (Chapter 4). Eleven explanatory variables including three transient climate variables (precipitation, air temperature and solar radiation) and eight static soil property variables are considered in developing the ANN models. The models are then extrapolated to the global scale to estimate monthly CH4 emissions from 1979 to 2099. Significant interannual and seasonal variations of wetland CH4 emissions exist in the past four decades, and the emissions in this period are most sensitive to variations in solar radiation and air temperature. This study reduced the uncertainty in global CH4 emissions from wetlands and called for better characterizing variations of wetland areas and water table position and more long-term observations of CH4 fluxes in tropical regions.
Finally, in order to study a new pathway of CH4 emissions from palm tree stem, I develop a two-dimensional diffusion model. The model is optimized using field data of methane emissions from palm tree stems (Chapter 5). The model is then extrapolated to Pastaza-Marañón foreland basin (PMFB) in Peru by using a process-based biogeochemical model. To our knowledge, this is among the first efforts to quantify regional CH4 emissions through this pathway. The estimates can be improved by considering the effects of changes in temperature, precipitation and radiation and using long-period continuous flux observations. Regional and global estimates of CH4 emissions through this pathway can be further constrained using more accurate palm swamp classification and spatial distribution data of palm trees at the global scale.
(8232060), Yiwen Bao. "INNOVATIVE COLD PLASMA-ASSISTED EXTRACTION FOR BIOACTIVE COMPOUNDS FROM AGRICULTURAL BYPRODUCTS." Thesis, 2020.
Знайти повний текст джерелаFruits play a necessary role in the human diet, and their cultivation is important to the prosperity of any country worldwide. However, fruit waste generated in large quantities in agricultural value chain is normally used to feed animals or directly disposed to landfill, ending up with low economic value and a heavy environmental burden. Agricultural waste that contains significant amounts of bioactive compounds can be utilized as byproducts and valorized through bioactives recovery. Conventional bioactive compounds extraction includes intensive uses of organic solvents and also has relatively low efficiency. Therefore, an environment-friendly alternative with higher extraction efficiency is needed. Cold plasma can convert gaseous medium to a highly reacting state with low energy cost, generating reactive species that are able to disrupt cell structures as well as modify material surfaces. This study has developed an innovative cold plasma-assisted extraction technology to enhance the recovery of bioactive compounds from fruit processing byproducts. The objectives of this study are to examine the effects of dielectric barrier discharge plasma on fruit pomaces, in terms of (i) surface microstructure and properties, (ii) extraction efficiency of their bioactive compounds, and (iii) bioactives composition and nutritional value of their extracts.
High voltage atmospheric cold plasmas (HVACP) generated with different working gases (air, argon, helium and nitrogen) were applied on tomato pomace (TP). In addition to creating ruptures on TP epidermal cells, HVACP treatments were found to decrease the water contact angles of tomato peels and accelerate the drying of tomato fruits, indicating the formation of more hydrophilic surfaces. Helium and nitrogen plasmas-treated TP showed increased PC extraction yields by 10%, and all HVACP-treated samples exhibited higher AA and changes in their phenolic compositions.
Grape pomace (GP) from red wine production was treated by helium-HVACP for different time periods (5, 10 and 15 min). Similar cell structure disruption and surface hydrophilicity enhancement were observed, and the effects became more significant as treatment extended. HVACP treatment also increased the total phenolic content in GP extracts, by 10.9−22.8%, which contained a higher anthocyanin concentration and showed an improved AA (16.7−34.7%). Furthermore, competitive effects of HVACP treatment on PC extractability enhancement and their degradation were observed.
The results of this study have proved that HVACP-assisted extraction successfully improved the extraction efficiency of bioactive compounds from fruit pomace and enhanced the nutritional quality of their extracts. This novel technology is a promising method for valorizing different agriculture byproducts into functional food ingredients and nutraceuticals with high nutritional values, which thus can bring significant economic benefits to the agricultural, food and nutraceutical industries.
(8802989), Neeraja Balasubrahmaniam. "LINKING INFANT LOCOMOTION DYNAMICS WITH FLOOR DUST RESUSPENSION AND EXPOSURE." Thesis, 2020.
Знайти повний текст джерелаInfant exposure to the microbial and allergenic content of indoor floor dust has been shown to play a significant role in both the development of, and protection against, allergies and asthma later in life. Resuspension of floor dust during infant locomotion induces a vertical transport of particles to the breathing zone, leading to inhalation exposure to a concentrated cloud of coarse (> 1μm) and fine (≤ 1μm) particles. Resuspension, and subsequent exposure, during periods of active infant locomotion is likely influenced by gait parameters. This dependence has been little explored to date and may play a significant role in floor dust resuspension and exposure associated with forms of locomotion specific to infants. This study explores associations between infant locomotion dynamics and floor dust resuspension and exposure in the indoor environment. Infant gait parameters for walking and physiological characteristics expected to influence dust resuspension and exposure were identified, including: contact frequency (steps min-1), contact area per step (m2), locomotion speed (m s-1), breathing zone height (cm), and time-resolved locomotion profiles. Gait parameter datasets for standard gait experiments were collected for infants in three age groups: 12, 15, and 19 months-old (m/o). The gait parameters were integrated with an indoor dust resuspension model through a Monte Carlo framework to predict how age-dependent variations in locomotion affect the resuspension mass emission rate (mg h-1) for five particle size fractions from 0.3 to 10 μm. Eddy diffusivity coefficients (m2 s-1) were estimated for each age group and used in a particle transport model to determine the vertical particle concentration profile above the floor.
Probability density functions of contact frequency, contact area, locomotion speed, breathing zone height, and size-resolved resuspension mass emission rates were determined for infants in each group. Infant standard gait contact frequencies were generally in the range of 100 to 300 steps min-1 and increased with age, with median values of 186 steps min-1 for 12 m/o, 207 steps min-1 for 15 m/o, and 246.2 steps min-1 for 19 m/o infants. Similarly, locomotion speed increased with age, from 67.3 cm s-1 at 12 m/o to 118.83 cm s-1 at 19 m/o, as did the breathing zone height, which varied between 60 and 85 cm. Resuspension mass emission rates increased with both infant age and particle size. A 19 m/o infant will resuspend comparably more particles from the same indoor settled dust deposit compared to a 15 m/o or 12 m/o infant. Age-dependent variations in the resuspension mass emission rate and eddy diffusivity coefficient drove changes in the vertical particle concentration profile within the resuspended particle cloud. For all particle size fractions, there is an average of a 6% increase in the resuspended particle concentration at a height of 1 m from the floor for a 19 m/o compared to a 12 m/o infant. Time-resolved locomotion profiles were obtained for infants in natural gait during free play establish the transient nature of walking-induced particle resuspension and associated exposures for infants, with variable periods of active locomotion, no motion, and impulsive falls. This study demonstrates that floor dust resuspension and exposure can be influenced by the nature of infant locomotion patterns, which vary with age and are distinctly different from those for adults.
(6634604), Khadija M. Jawad. "The UV spectroscopy of 3-phenyl-2-propynenitrile and it's methylated derivatives." Thesis, 2019.
Знайти повний текст джерелаFor decades there has been interest in understanding early prebiotic Earth, including its atmospheric chemistry. Saturn’s moon Titan is the only other body in our Solar System with an atmosphere thought to resemble that of early Earth’s, and for this reason it has garnered a lot of attention over the years. Much is now known about the smaller molecules present in that atmosphere, starting with the most abundant, N2 and CH4, and going up to slightly larger molecules such as cyanoacetylene and benzene. As the molecules get larger, however, so does the gap in knowledge, especially as it pertains to nitriles. This dissertation aims to add to the story of Titan’s nitriles by first characterizing a molecule thought to be the photochemical product of the reaction between cyanoacetylene and benzene, 3-phenyl-2-propyne-nitrile (PPN). The UV spectra of PPN proved immensely interesting due to the strong presence of in-plane and out-of-plane vibrations of b2 and b1 symmetry, respectively. This is possibly a result of strong vibronic coupling between several excited electronic states or Coriolis coupling between complementary b1 and b2 vibrational levels. The multi-layer extension of the multi-configuration time dependent Hartree (ML-MCTDH) algorithm was used to understand how the excited states and the vibrational levels might interact, and emission and absorption spectra were modeled and compared to the experimental spectra. The second group of molecules studied included the ortho-, meta-, and para-methyl PPN. Strong methyl rotor activity is seen in the m-methyl PPN, with some activity in the p-methyl PPN. The methyl rotor activity in the m-methyl PPN is similar to other meta-substituted toluenes, and allows us to describe the methyl rotor barrier height in both ground and excited electronic state. Additionally, in all three methylated PPNs we see evidence for strong vibronic coupling in the abundance of out-of-plane vibrations, as had been seen in PPN.
Pietrzykowski, E. "New Tools for Determining Incidence and Severity of Mycosphaerella Leaf Disease in Eucalypt Plantations." 2007. http://eprints.utas.edu.au/5802.
Повний текст джерела(5931173), Jessica Merkling. "Development of an Environmental DNA Assay for Eastern Massasauga." Thesis, 2019.
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