Chiral Liquid Crystals (CLCs) can selectively reflect light of a specific wavelength when the period of its helically twisted structure is appropriately chosen and white light propagates along the helical axis. This phenomenon makes CLCs attractive for reflective-color display, without the needs of backlighting, polarizers, or color filters. Polymer Dispersed Chiral Liquid Crystals (PDCLC) have been developed for reflective switchable, bistable color display. However they suffer from high external driving voltage, low reflectivity, and high cost in pretreatment of the substrates. The key to solve these problems is to understand and control the anchoring behavior of CLC at a polymer surface. This research has two purposes: to develop PDCLC films with high reflectivity and to investigate the factors affecting the anchoring behavior of CLC at the polymer surface of the film. Specifically, commercially available chiral dopant and nematic liquid crystals were carefully chosen to formulate the CLCs reflecting different color. These CLCs are mixed with various acrylate and methacrylate monomers respectively, and UV cured at varied conditions to obtain PDCLC films. The anchoring behavior of these films is characterized using polarized optical microscopy, confocal microscopy, and microscopic-spectrophotometer. The factors influencing the anchoring behavior include chemical structure of the monomers, effective diameter of individual cells in PDCLC, thickness of individual cells in PDCLC, and the pitch of CLC, among which the chemical structure of the monomers is the most important. The PDCLC film made with n-hexyl methacrylate is found to selectively reflect light with the reflectivity larger than that of pure CLC with the same pitch.

In the past, the oil and gas industry has typically used the single gradient system to drill wells offshore. With this system the bottom hole pressure was controlled by a mud column extending from the drilling rig to the bottom of the wellbore. This mud column was used to achieve the required bottom hole pressure. But, as the demand for oil and gas increased, the industry started exploring for oil and gas in deep waters. Because of the narrow margin between the pore and fracture pressures it is somewhat difficult to reach total depth with the single gradient system. This led to the invention of the dual gradient system. In the dual gradient method, heavy density fluid runs from the bottom hole to the mudline and a low density fluid from the mudline to the rig floor so as to maintain the bottom hole pressure. Several methods have been developed to achieve the dual gradient drilling principle. For this research project, we paid more attention to the liquid lift, dual gradient drilling (riser dilution method). This method of achieving dual gradient drilling was somewhat different from the others, because it does not utilize elaborate equipment and no major changes are made on the existing drilling rigs. In this thesis the technical feasibility of using the liquid lift method over the other methods of achieving dual gradient drilling was determined. A computer program was developed to simulate the wellbore hydraulics under static and dynamic conditions, injection rate and base fluid density required to dilute the riser fluid and finally, u-tubing phenomena. In this thesis we also identified some problems associated with the liquid lift method and recommendations were made on how these problems can be eliminated or reduced. Emphases were placed on the effect of u-tubing, injection rate of base fluid at the bottom of the riser and well control issues facing this system.

Liquid loading in producing gas wells is the inability of the produced gas to remove produced liquids from the wellbore. A review of existing flow loops worldwide revealed that specialized areas of research such as liquid loading in gas wells are still lacking dedicated test facilities. This project presents the design of a new dedicated facility to be located at the TowerLab at the Richardson building with adequate operating conditions to reproduce the flow regimes encountered prior to and after the onset of liquid loading in gas wells. The facility consists of a compressed air system, pipelines for air and water, a pressure vessel containing glass beads, an injection manifold, and flow control and monitoring devices. Our results show that three compressors working in parallel is the most technical and economic configuration for the TowerLab based on the overall costs provided by the supplier, the footprint but most importantly the flexibility. The design of the pressure vessel required a cylindrical body with top and bottom welded-flat head covers with multiple openings to minimize its weight. The pipelines connecting major equipment and injection manifold located at the pressure vessel were selected based on the superficial velocities for air and water. These values also showed the need for independent injection using two manifolds instead of commingling flow through a tee joint. The use of digital pressure gauges with an accuracy of 0.05 to 25% and coriolis or vortex meters to measure air flowrate is also suggested. For the water line, installation of turbine meters results in the most economic approach.

Liquid loading is a serious problem in gas wells. Many proven artificial lift methods have been used to alleviate this problem. However, a complete workflow to determine the most suitable artificial lift method for given well conditions does not exist. In 2008, Han Young Park presented his thesis of decision matrix tool using a decision tree technique for data mining that determined the best artificial lift method for liquid loading in gas wells from seven artificial lift methods: plunger lift, gas lift, ESP, PCP, rod pump, jet pump, and piston pump. He determined the technical feasibility and the cost evaluation of these seven techniques. His workflow consisted of three rounds. The first round was the preliminary screening round. By using all input well conditions, the impractical techniques were screened out. In the second round, all the techniques from round one were graded and ranked. In the third round, the economic evaluation was performed by using cost for each artificial lift method and assuming the constant additional gas production per day to determine net present value (NPV) and internal rate of return (IRR). In this thesis, we propose an extended workflow from the Han-Young’s thesis for the decision matrix tool. We added integrated production simulations (reservoir to wellhead) step with commercial software in between the second and third round. We performed simulations of the various artificial lift methods to see the additional gains from each technique. We used the additional gas production resulted from simulation to calculate economic yardsticks (the third round), NPV and IRR. Moreover, we made the decision matrix more complete by adding three more liquid unloading techniques to the decision matrix: velocity string, foam injection, and heated tubing. We have also updated all screening conditions, the technical scores, and the costs for the decision matrix from the previous study using literature reviews, information from the project’s sponsor, information from service company and our own judgment. The aim of the decision matrix is to allow operators to screen quickly and efficiently for the most suitable artificial lift method to solve the liquid loading problem under given well conditions.

In this study, we research the characteristic of light in the waveguide with etched ITO channels. The anisotropic of liquid crystal induces the index of reflection changed while applying alternative voltage. The etched ITO electrode will become waveguide in cell by applying alternative voltage. We observe the characteristic of light with different number of channels. Single ITO channel results graded type reflection index distribution, and it is similar to graded type optical fiber. We find that the laser beams will induce coupling in channels with many etched ITO channels.

We propose to develop a voltage-controllable multi-guide directional coupler in a planar nematic liquid crystal cell. The ITO grating-like electrodes are fabricated by the etching technique, and the director of liquid crystals will be aligned to the direction of applied electric field. Owing to the uniaxial property of liquid crystals, the difference of refractive index between two neighboring channels is increased with the applied voltage. Therefore, the coupling efficiency among grating-like multi-guide is also increased with the applied voltage. By using the combination of microscope and CCD system, the dynamic coupling can be observed under the distribution of grating-like electric field. The propagation of light in each channel can be selected by the controllable voltage between the electrodes of the individual channel. The intensity distribution of coupling in the transverse direction can be obtained by analyzing the image captured from the microscope and CCD system.

We hope to achieve the goal of improving molecule nature of the liquid crystal by change the functional group or the symmetry of the molecule. In the thesis, the derivatives of dibenzophenazine are synthesized and their mesogenic properties are investigated. Polarised optical microscopy (POM) and differential scanning calorimetry (DSC) studies show all these compounds to exhibit a very wide mesophase range. These mesophases are identified as columnar hexagonal phases by X-ray diffraction (XRD).

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Optical measurement is a very important science in present times. Generally, optical interference is applied in precise measuring. In this thesis, we use the opto-electric properties of liquid-crystal layers and the phase-shifting shearing interferometer will be applied. Clear patterns should be figured when measuring optical properties traditional interferometers. A new interferometer called phase-shifting shearing interferometer was developed recently. It is not necessary to appear clear patterns in measurements. In application to this interferometer, the phase information got by way of shifting the reference lens that can control phase differences. Phase controlled in thus method is mostly by the step motor or the PZT installation. Now we replace this installation by liquid-crystal layers since the accuracy of liquid-crystal layers controlled by voltage is better than the mechanical installation. The measuring precision is improved wide. In this paper, we study the optical properties under the application both DC and AC voltage to a series of thickness of the liquid-crystal layer, and the suitable condition of liquid-crystal layers to apply to the phase-shifting shearing interferometer.

Abstract There are three parts in this paper. The first, we study the mechanism of soliton in nematic liquid crystal (NLC), molecules of NLC will be rotated easily by optical field while we apply an external electric field. Then the effective refraction index is changed. The light beam in NLC will create spatial soliton by producing the effect of self-focusing to balance the diffraction. Second, we study the interaction between solitons. One soliton will create a potential well of refraction index. The other one will be attracted in the potential well. These two solitons propagate in the form of spiral, if the separated distance and the angle are suitable. And the third, we observe the phenomenon with probe beam in the path of soliton. The path of the soliton forms a channel like a wave guide. The probe beam insert into the path of the soliton with different angles. The probe beam collides with the soliton in the proper range of angles will follow its path.