Yes / The purpose of this paper is to demonstrate: 1) that silent substitution stimuli can be used generate electro-retinograms (ERGs) that effectively isolate rod photoreceptor function in humans without the need for dark adaptation and 2) that this approach constitutes a viable alternative to current clinical standard testing protocols. Rod-isolating and non-isolating sinusoidal flicker stimuli were generated on a 4 primary LED ganzfeld stimulator to elicit ERGs from non-dark adapted participants with normal and compromised rod function. Responses were subjected to Fourier analysis and the amplitude and phase of the fundamental were used to examine temporal frequency and retinal illuminance response characteristics. ERGs elicited by rod isolating silent substitution stimuli exhibit low-pass temporal frequency response characteristics with an upper response limit of 30Hz. Responses are optimal between 5 – 8 Hz and between 10-100 photopic Td. There is a significant correlation between the response amplitudes obtained with the silent substitution method and current standard clinical protocols. Analysis of signal to noise ratios reveals significant differences between subjects with normal and compromised rod function. Silent substitution provides an effective method for the isolation of human rod photoreceptor function in subjects with normal as well as compromised rod function when stimuli are used within appropriate parameter ranges. Translational Relevance: This method of generating rod ERGs rod isolation can be achieved without time consuming periods of dark adaptation and provides improved isolation of rod- from cone-based activity and will lead to the development of faster clinical electro-physiological testing protocols with improved selectivity.

Two topics from nuclear engineering field are included in this dissertation. One study is the air-ingress phenomenon during a loss of coolant accident (LOCA) scenario, and the other is a 5-by-5 bundle assembly problem under a design of PWRs. The objectives are to investigate the Kelvin-Helmholtz instability of the gravity-driven stratified flows inside a coaxial pipe and the effects caused by two types of spacers at the downstream of the rod bundle problem. Richardson extrapolation is used for the grid independent study. Simulation results give good agreements with the experiments. Wavelet analysis and Proper Orthogonal Decomposition (POD) are used to study the flow behaviors and flow patterns. For the air-ingress phenomenon, Brunt-Vaisala frequency, or buoyancy frequency, predicts a frequency of 2.34 Hz, which is confirmed by the dominant frequency of 2.4 Hz obtained from the wavelet analysis between times 1.2 s and 1.85 s. For the rod bundle study, the dominant frequency at the center of the subchannel is given as 2.4 Hz with a secondary dominant frequency of 4 Hz and a much minor frequency of 6 Hz. Generally, wavelet analysis has much better performance than POD in the air-ingress phenomenon that is a strongly transient scenario; they both appropriate for the rod bundle study. Based on this study, when the fluid pair in a real condition is used, the time which air intrudes into the reactor is predictable.

This report accounts for investigations of ways to reduce the calculation times forsimulations of falling control rods in boiling water reactors done prior to everyreactor startup, known as RIA-calculations. Two methodologies to lower thecalculation times have been proposed, developed and implemented in a set ofmatlab-scripts, which are fully compatible with the previously used methodology.The new methodologies have been applied on 17 authentic power cycles at the threeForsmark reactors, whereby a reduction in calculation times by 70 to 90 % could bedemonstrated while still confidently maintaining the analysis performance. Thesimulations made and the basis of the new methodologies are described in detail inthis report, and possible steps to further lower the calculation times are alsoproposed.

Currently, finite element analysis (FEA) serves as the only analytical tool used in the evaluation of seals. The FEA does not allow the dynamic analysis of the seal, which must be performed experimentally. As a result, the designing of a seal can be a costly and extensive procedure. The aim of this project has been to develop a numerical model and computer program that will have the ability to predict key seal performance characteristics, such as leakage and friction. This numerical model provides a means for evaluating potential seal designs, which can be performed without having to endure the costs of creating and evaluating the performance of the seal. Thus, the numerical model reduces the time and cost involved in evaluating seal designs. The numerical model developed differs from previous models as the effects of mixed lubrication and surface roughness are investigated. This model consists of three coupled analyses of fluid mechanics, deformation, and contact mechanics. After computational procedure has converged coupling the three analyses, auxiliary calculations are performed to obtain the quantities of leakage rate and friction force. These obtained results then allow the evaluation of the seal design, which will lead to better seal designs with lower friction and less (or no) leakage. The results obtained for a typical hydraulic seal show that the leakage characteristics depend strongly on the seal roughness.

In the study, a self-developed electrolytic micro-machining tester is employed to investigate the effects of the supply voltage and the highest position of the workpiece relative to the tool on the geometry of the tungsten rod. The peripheral surface of the iron needle (tool) is insulated by an insulator and its tip with a diameter of 50£gm is exposed to the electrolyte as a cathode. The tungsten rod (workpiece) with 200£gm in diameter reciprocates as an anode. Both the cathode and the anode are dipped into an aqueous electrolyte of 2wt % sodium hydroxide to proceed electrochemical machining. Experimental results show that since the length and the diameter of the workpiece are varied during the machining process, it is necessary to manually adjust the highest position and the gap between the workpiece and the tool in each reciprocating motion to achieve a uniform tungsten rod. Moreover, because of the higher removal rate of the workpiece at the higher supply voltage, it is hard to control the geometry of the workpiece. On the contrary, the geometry of the workpiece can be controlled at the lower supply voltage. Finally, the workpiece is first machined at the higher supply voltage, and then the supply voltage is switched to the lower one to achieve a uniform tungsten rod with 2£gm in diameter and 200£gm in length, or 100 in aspect ratio.

It is a common problem that the cooling water loop in an HVAC or refrigeration plant is suffering from scaling, corrosion, and bacteria attacks, especially in an open-loop designs. The reason is that, through the open water loop, various kinds of contaminants were trapped and migrated along the water flow, causing condenser scaling, which in turn, leading to its poor thermal performances. The experiment conducted in this study revealed that each condenser temperature increase of 1 ¢J, accounts for a COP decrease of 2.4% to 2.8%.Serious scaling problem might even lead to system malfunction, and hazardous environmental problems. Conventionally, water-treatment in the condenser cooling water loop can be categorized into two parts, namely, the chemical and the physical methods. The chemical treatment is mainly performed by injecting chemicals, mostly acids, into the water loop so that it can circulate through the system and causing scales to peer off from the condenser tubes. In response to the cry of environmental protection, physical treatment has become increasingly important, which utilizes magnetic forces as the primary working principle. The main theme of this study is to validate this principle by full-scale experiments. The Zeta Rod system has been developed under the DLVO theory, with significant performance and is environmentally friendly. Experimental investigation has been performed in comparing the temperature differentials across a condenser, before and after the treatment. The result validated that it has increased from 3.9¢J to 4.2¢J and enhanced the thermal performances of the condenser accordingly.

ABSTRACT A water-soluble rigid-rod polyelectrolyte sPBI-PS(Li+) could be doped with LiI and cast as a freestanding film from aqueous solution showing a room-temperature in-plane DC conductivity (s|| ) of 8.3¢®10-3 S/cm. However, the cast film assumed an anisotropic microstructure due to preferential orientation of the rigid-rod backbone leading to an out-of-the plane DC conductivity (s^) which was three orders smaller than those of the s||, and severely limited its applications as a solid polyelectrolyte for thin-film battery. In addition to synthesizing rigid-rod polyelectrolyte sPBI-PS(Li+) for comparison, this study used 2-sulfo-terephthalic acid and isophthalic acid in ratios of 15¡G1, 25¡G1, or 50¡G1 for copolycondensation reaction making the rigid-rod backbone of sPBI-PS(Li+) become articulated. Further reaction with 1,3-propanesultone pendants, the rigid-rod polyelectrolyte was changed into a new water-soluble articulated rigid-rod polyelectrolyte A-sPBI-PS(Li+). Various analyses were applied to ascertain chemical structure, purities, thermal properties and molecular weight of synthesized monomers and polymers. Freestanding films of sPBI-PS(Li+) and A-sPBI-PS(Li+) were cast from aqueous solutions doped with LiI, LiBF4, or LiCF3SO3 for various concentrations up to 5 wt.%. Thin-film room-temperature s|| of sPBI-PS(Li+) could be 3.15´10-3 S/cm, and of A-sPBI-PS(Li+) could be 2.76´10-3 S/cm. X-ray scattering and electron microscopic results suggested that the sPBI-PS(Li+) cast film was in-plane isotropic but out-of-the plane anisotropic, and the A-sPBI-PS(Li+) cast film was three-dimensionally isotropic.

A water-soluble rigid-rod polyelectrolyte sPBI-PS(Li+) could be doped with LiI and cast as a freestanding film from aqueous solution showing a room-temperature in-plane DC conductivity (

ABSTRACT sPBI is a heterocyclic aromatic polymer assuming a para- catenated backbone yielding a rod-like configuration. Because of its rigidity, this rod-like molecule displays superior mechanical tenacity, thermo-oxidative stability, and solvent resistance. It is also the precursor of rigid-rod solid polyelectrolyte exhibiting high solubility and superior ionic conductivity. Isotropic solution were prepared by dissolving sPBI in distilled methanesulfonic acid containing 0.0, 0.989, 4.76, 9.09, 15.0, 20.0, 23.1 wt. % lithium ion of dopants of LiCF3SO3 or LiN(CF3SO2)2. The room-temperature DC conductivity of sPBI cast film doped with 15.0 wt. % LiN(CF3SO2)2 parallel (

Dimensional stability is an important aspect of fuel mechanical design and licensing of new fuel designs for nuclear power plants. Dimensional changes within the reactor can affect the safety margins against overheating of the cladding and the pellets, therefore it is crucial that the dimensional changes are kept to a minimum. The profits per produced kiloWatt hour continue to decrease for the Swedish nuclear power plants. Some reactors are even operated with a calculated loss. To reduce fuel costs and thereby improve the profit some reactors are operated with higher uranium enrichment, so that the assemblies can reach a higher average burnup. This increases the neutron fluence to the pellets, cladding an spacers. Fluence is the parameter that most strongly affects dimensional changes within the reactor. This master thesis was carried out at Vattenfall Nuclear Fuel in Solna during 2015. The purpose of this study is to evaluate the different dimensional changes in the fuel designs operating in Ringhals 2 ,3 and 4. The gained results may improve possibilities to verify if fuel assemblies with observed rod bow are safe for continued operation. Inspection videos called visual inspections and 4-camera videos are captured each year in each of the three reactors. From these videos the distance to the top- and bottom plate was measured as well as the magnitude of the rod bow. The results show that Ringhals 2 fuel designs R2L2b and R2L1 make it possible for rod growth through the uppermost grid. This has been achieved by lesser grid spring force and at the present burnup no severe rod bow is observed for either of the fuel designs. In Ringhals 3 and 4 the fuel designs R34L1 and R34L2 show similar trends in rod growth and have the same magnitude of rod bow though it appears in different spans in the assembly. A comparison of the major rod-to-rod gaps and the adjacent rods axial growth has led to the conclusion that rod bow is driven by manufacturing differences within the rods and spacers.