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<p>Dye-sensitized Solar Cells (DSSCs) with liquid electrolyte lack long term stability because of volatility of the electrolyte and assembly problems. Replacement of the volatile liquid-state electrolyte with solid-state hole conductor thus becomes necessary. A small molecule based hole conductor, Copper Phthalocyanine (CuPc), is proposed here to replace the liquid electrolyte, for its intrinsic thermal and chemical stabilities. However, a lower short circuit current was found in the CuPc solid state device from I-V curve, which is closely related to the inefficient hole transport in the CuPc thin film. Therefore, Two-Dimensional Grazing Incidence X-ray Diffraction (2D GIXRD) is utilized to study the phase and texture of CuPc thin film. It is found that the CuPc thin film has a cystallinity of greater than 80%, which is good for hole conducting. However, the <em>β</em>-phase formation lowers the overall hole conductivity. The hole conductivity of <em>β</em>-phase CuPc is two orders of magnitude smaller than that of <em>α</em>-phase CuPc, due to a less overlap in the <em>π-π</em> stacking. As a result, the low hole conductivity of <em>β</em>-phase CuPc is the reason that leads to an inefficient hole transport and reduces the short-circuit current of the solid-state DSSC. Therefore, future work will be necessary to isolate <em>α</em>-phase CuPc, in order to be successfully applied into the solid-state DSSCs.</p> / Master of Science (MSc)

Dye tracer and time-lapse ground-penetrating radar (GPR) were used to image preferential flow paths in the shallow, unsaturated zone on hillslopes in two adjacent watersheds within the Susquehanna-Shale Hills Critical Zone Observatory (CZO). At each site we injected about 50 L of water mixed with brilliant blue dye (4 g/L) into a trench cut perpendicular to the slope (~1.0 m long by ~0.20 m wide by ~0.20 m deep) to create a line of infiltration. GPR (800 MHz antennae with constant offset) was used to monitor the movement of the dye tracer downslope on a 1.0 m x 2.0 m grid with a 0.05 m line spacing. The site was then excavated and the stained pathways photographed to document the dye movement. We saw a considerable difference in the pattern of shallow preferential flow between the two sites despite similar soil characteristics and slope position. Both sites showed dye penetrating down to saprolite (~0.40 m); however, lateral flow migration between the two sites was different. At the Missed Grouse field site, the lateral migration was ~0.55 m as an evenly dispersed plume, but at distance of 0.70 m a finger of dye was observed. At the Shale Hills field site, the total lateral flow was ~0.40 m, dye was barely visible until the excavation reached ~0.10 m, and there was more evidence of distinct fingering in the vertical direction. Based on laboratory and field experiments as well as processing of the radargrams, the following conclusions were drawn: 1) time-lapse GPR successfully delineated the extent of lateral flow, but the GPR resolution was insufficient to detect small fingers of dye; 2) there was not a distinct GPR reflection at the regolith-saprock boundary, but this interface could be estimated from the extent of signal attenuation; 3) the preliminary soil moisture conditions may explain differences in the extent of infiltration at the two sites; 4) rapid infiltration into the underlying saprock limited the extent of shallow lateral flow at both sites and can be seen using the mass balance calculation and the lateral extent of dye within the radargrams; and 5) variations in flow patterns were observed between sites with similar settings at Susquehanna-Shale Hills CZO. / Geology

yes / This paper presents field measurements in which dye solute was injected into coastal sand to investigate contaminant advection in intertidal beach sand. The measurements show the pathways of a contaminated plume in the unsaturated zone during both the flood and ebb tides. A prescribed amount of dye tracer solution was directly injected through the topsoil, with average porosity 0.3521±0.01, at predetermined locations of the River Mersey’s outer estuarial beach during ebb-tide. The injected dye was monitored, sampled and photographed over several tidal cycles. The distinctive features of the plume (full two dimensional cross-sections), sediments and water-table depth were sampled in-situ, close to the injection point (differing from previous contaminant monitoring tests in aquifers). The advective movement is attributed to tidal impact which is different from contaminant transport in aquifers. The experimental results show that plumes have significantly large spatial variability, diverging upwards and converging downwards, with a conical geometric shape which is different from the usual spherical/elliptical shape reported in literature. The mean vertical motion of the plume reaches three times the top-width within ten tidal cycles, exceeding the narrow bottom-width by a factor of order 2. The observed transport features of the plume within the beach sand have significant relevance to saltwater intrusion, surface water and groundwater quality. The field observations are unique and can serve as a valuable benchmark database for relevant numerical studies. / China Ministry of Science and Technology 973 program (2014CB745001), Special Program of future development in Shenzhen (201411201645511650) and Shenzhen Key Laboratory for Coastal Ocean Dynamic and Environment（ZDSY20130402163735964).

Nematic liquid crystals possess large optical nonlinearities owing to their large refractive index anisotropy coupled with the collective molecular reorientation. Doping absorbing dyes into liquid crystals increases their optical responses significantly due to increased absorption in the visible region, absorption-induced intermolecular torque, cis-trans photoisomerization, and other guest-host effects. The guest-host mixtures can be employed in display applications, optical storage devices, and others. In this dissertation, nonlinear optical studies were carried out on dye-doped nematic liquid crystal cells. The main objectives of the studies were to distinguish and characterize the several processes that can lead to the formation of dynamic gratings of different types in the samples, and to study the photorefractive and the orientational responses of these samples. Furthermore, we tried to explain and model the dynamical behaviors of the observed grating formations. The experimental techniques employed in this study include asymmetric two-beam coupling, forced light scattering, and polarization holographic method. The asymmetric two-beam coupling experiments revealed that the induced grating was a photorefractive phase grating created by the nematic director reorientation within the plane of incidence. The dynamics of the beam coupling showed that two different mechanisms with different temporal responses were involved. The grating translation technique identified both gratings as pure photorefractive index gratings with phase shifts of ~ p/2 between the grating and the interference pattern. In addition, the dynamical behavior of the grating formation, obtained from forced light scattering experiments, also exhibited a two-time constant response. The dynamical behaviors of the build-up and decay of the photocurrent were investigated. The two dynamics exhibited both a two-time constant behavior, suggesting that the origin of the two-time constant dynamics observed in the two-beam coupling and the forced light scattering experiments resides in the process of photo-charge generation. The photorefractive gain coefficients were found to be in the range of 100 – 400 cm-1. The values of the nonlinear optical Kerr index (~ 0.08 cm2/W) measured in samples with certain dye/liquid crystal combinations are higher than what has been observed in other dye-doped nematics and other liquid crystal/polymer systems. All the samples showed a threshold behavior with respect to the magnitude of the applied electric field. This threshold behavior was observed both in forced light scattering experiments and polarization holographic experiments. We believe that the origin of this threshold lies in the process of photogeneration, which was found to exhibit the same threshold behavior at the same value of the applied voltage. An asymmetry of the photorefractive gain with respect to the direction of the applied electric field was observed in samples with high dye concentration. This was attributed to the beam fanning effect, which has also been observed in other high-gain photorefractive materials. Polarization holographic measurements showed that the dye enhancement effect is primarily due to the intermolecular interaction between the dye molecules and the liquid crystal host, and that the trans-cis photoisomerization plays a lesser role. The photoinduced orientational response was also studied using polarization holographic experiments. A number of observations confirmed that the birefringent grating is due to the nematic director reorientation within the plane of incidence, under the combined effect of the applied electric field and the optical field. The diffraction efficiency was found to depend linearly on the writing beam power, while the dependence of the self-diffraction efficiency on the writing beam power roughly assumes a cubic relationship. The dynamical behavior of the birefringent grating formation was investigated. The build-up dynamics was found to be best modeled as a double-time constant response, while the decay is best fitted by a single exponential. The response of the samples to an oscillating electric field was studied as a function of the modulation frequency. Very interesting and reproducible dynamics was observed, revealing the complex dynamical response of the liquid crystal director to the magnitude and rate of change of an applied electric field. The small signal response was also measured, but did not reveal any sign of a resonance behavior. The conductivity and the photoconductivity of the samples were measured. The relationship between the measured current and the applied voltage was found to be cubic at low applied voltage, and to become linear at higher applied voltage. We could explain this behavior using a double-charge-injection-in-a-weak-electrolyte model, but this is only one of the possible mechanisms that could explain this behavior. The photocurrent was found to increase linearly with the illumination power, which indicates that the charge carrier recombination rate is proportional to the carrier density. The measured electrical conductivity was found to be proportional to the square root of the dye concentration, confirming the validity of the proposed charge-injection model. / Ph. D.

The objectives of this research were (1) to develop scales of preferred image sharpness for thermal dye transfer prints and (2) to relate these scales to an objective measurement of image quality. Interval scales were developed using two different indirect scaling techniques, paired comparison and rank ordering, for three groups of participants (novice photographers, advanced amateur photographers, and Kodak image quality experts). Differences between scales developed through the separate scaling procedures were minor, suggesting that either procedure would produce a reliable and valid interval scale. Given the time required to perform the method of paired comparisons, the method of rank ordering would likely be the preferred procedure. The results from multiple range tests of the interval scales found that higher levels of image sharpening (filter levels 1.5x to 2.5x) were generally preferred. However, for some conditions, particularly the portrait, lower levels of sharpening were generally preferred. While it appears that the preferred level of image sharpness may be somewhat dependent upon scene content, participants always preferred a small amount of sharpening to none at all. For all conditions examined, stimuli that received no sharpening were the least preferred. In relating interval scales to an objective measure of image quality, scale values developed from within a level of addressability were highly correlated with values of modified MTFA for all participant groups. These correlations show that a strong relationship exists between preferred levels of image sharpness and increasing levels of luminance modulation for edges in thermal prints. However, values of modified MTFA were not well correlated with interval scale values developed from experts participants for the between levels of addressability portion of the experiment. Values of MTFA were considered modified due to limits that were imposed on the bounds of integration. These results suggest that the preferences of experts may not represent those of the average consumer for desired levels of thermal print sharpness. / Ph. D.

The purpose of this research was to design, fabricate and test a 1 liter per minute pilot plant with a cascading sequence of continuously stirred tank reactors. The object of the research was to chemically decolorize selected reactive-dye bath concentrates resulting from exhaustive dyeing, and to remove metals and DOC using Fenton's Reagent or the reductive chemicals, thiourea dioxide and sodium hydrosulfite. For the Fenton's Reagent studies, ferrous sulfate was premixed with the dye waste concentrate before overflowing to the first reactor. A feedback control system based on color remaining in the discharge was used to regulate reactants added. Transmittance was measured at several wavelengths (590, 540, and 438 nm) and the American Dye Manufacturers Institute (ADMI) value calculated. The results demonstrated that ADMI measurements could not be made on dark solutions (over 3000 ADMI) in the pilot plant and, typically, one wavelength was used for control. DOC removal was used as a means of determining the biological activity in aerated reactors following color removal. The initial pilot plant studies were conducted using Navy 106 jet-dye waste. Reductive pretreatment with thiourea dioxide resulted in 92.2% color removal with color returning upon aeration for an overall color removal of 76.6%. Oxidative pretreatment with Fenton's chemistry resulted in 98.8% color removal with overall color removal after aerobic treatment at 96.8%. Dissolved Organic Carbon (DOC) removal in aerobic treatment improved with oxidative pretreatment relative to reductive pretreatment on Navy 106 jet-dye concentrate. On site operation of the pilot plant on other dye wastes showed color removals above 95% and DOC removals of 38% and 19% for an azo-based red dye waste concentrate and a copper-phthalocyanine-based dye, Ming Jade, respectively. The soluble copper concentration in the Ming Jade was decreased from 19.2 ppm to 4.5 ppm. This corresponded to a 3-fold increase in suspended solids from 0.575 g/L to 1.505 g/L. The results showed that continuous oxidative pretreatment with a 15-minute residence time was controllable and more effective than reductive treatment for color removal. Oxidative pretreatment also decreased the soluble copper concentration in a copper containing waste water, and did not hinder biological activity. / Master of Science

Yes / Ex vivo wounded human skin organ culture is an invaluable tool for translationally relevant preclinical wound healing research. However, studies incorporating this system are still underutilized within the field because of the low throughput of histological analysis required for downstream assessment. In this study, we use intravital fluorescent dye to lineage trace epidermal cells, demonstrating that wound re‐epithelialization of human ex vivo wounds occurs consistent with an extending shield mechanism of collective migration. Moreover, we also report a relatively simple method to investigate global epithelial closure of explants in culture using daily fluorescent dye treatment and en face imaging. This study is the first to quantify healing of ex vivo wounds in a longitudinal manner, providing global assessments for re‐epithelialization and tissue contraction. We show that this approach can identify alterations to healing with a known healing promoter. This methodological study highlights the utility of human ex vivo wounds in enhancing our understanding of mechanisms of human skin repair and in evaluating novel therapies to improve healing outcome. / University of Manchester Strategic Fund; Wellcome Trust; BBSRC; Ministry of Higher Education, Malaysia Universiti; Sains Malaysia

Electrospinning and electrospraying are electrohydrodynamic processes used for the fabrication of nano- and microfiber membranes and the deposition of particles on the membrane. Despite the numerous research papers found in the literature on electrospun polymers and their application in water treatment, not much is reported on the functionalization of electrospun nano- or microfibers and the deposition of ceramic nanoparticles on their surface by electrospraying. The use of these two processes may increase the efficiency of membranes in removing contaminants. In the present research, the processes of electrospinning and electrospraying are described and the factors affecting electrospinning are investigated. All parameters affecting the production of smooth NFs and NPs are discussed. A literature review of the recent advances in electrospinning and electrospray applications, as well as the application of NFs membranes in water treatment, has been described. This research has been designed based on the knowledge gaps identified in the literature. Detailed experiments were carried out on the preparation of PAN_P and Cs_P NFs membranes by electrospinning technique, the NFs membranes were then functionalized with different functional groups. The membranes were used for removal (Chapter 3) and degradation (Chapters 4 and 5) of dyes synthetic solutions. In the case of degradation, the membranes were electrosprayed with TiO2 NPs. All membranes were characterized by standard spectroscopic, microscopic, surface analytical, and thermal methods. Adsorption of MB, RB, and ST from a synthetic aqueous solution on the membranes PAN and EA-g-PAN NFs decreased in the order PAN<EA-g-PAN. The adsorption isotherm for the dyes fitted well with the models of Langmuir and Freundlich. The values of the correlation coefficient (r2) for Langmuir varied from 0.940 to 0.995 and for Freundlich from 0.941 to 0.998. The slightly increased values of the correlation coefficient in the case of Freundlich indicate that condensation (physical adsorption) of dyes on the NFs membranes also occurred in addition to the formation of monolayers. PAN_P NFs membranes prepared by electrospinning were functionalized with DETA to produce a functionalized PAN _F NFs membrane. TiO2 NPs synthesized in the laboratory were anchored to the surface of the PAN_F NFs membrane by electrospray to prepare PAN _Coa. A second PAN_Co was prepared by embedding TiO2 NPs into the PAN_P NFs by electrospinning. A similar strategy was also used for the Cs and TiO2 NPs system. The PAN_Coa NFs membrane was used for the degradation of MO while the Cs_Coa NFs membrane was used for the degradation of MB. The higher photocatalytic activity of PAN _Coa NFs membranes (92%, 20 ppm, and 99.5%, 10 ppm) compared to PAN_Co NFs membranes (41.64%) was due to the smaller band gap, high surface roughness, and large surface area. Also, the higher photocatalytic activity of the Cs_Coa NFs membrane (89%) compared to TiO2/Cs composite (Cs_Co) NFs membranes (40%) was due to a balance between the band gap, high surface roughness, and lower surface area. BET showed that the isotherms and hysteresis were similar for all NFs membranes, and they were classified as isotherm type IV and hysteresis H3 (IUPAC), corresponding to mesopores and slit-shaped pores.