The low cycle fatigue test of IF steel was controlled at 0.6%, 0.4%, 0.2%, and 0.1% strain amplitude until the specimens cracking. After 10000 cycles at 0.4% strain amplitude, changed the strain amplitude from 0.4% to 0.2%. We chose the steps of the low cycle fatigue test under reducing amplitude at 1000, 10000, and 20000 cycles. In addition, after 10000 cycles at 0.6% strain amplitude, changed the strain amplitude from 0.6% to 0.2%. We chose the steps of the low cycle fatigue test under reducing amplitude at 3000, 20000 and 100000 cycles. Then we used electron microscope to observe the dislocation structure, and knew the dislocation morphology of evolution process under reducing amplitude. The dislocation structure evolution of IF steel at low strain amplitude (0.1%, 0.2%) during low cycle fatigue developed the loop patches, dislocation walls, and dislocation cells step-by-step by increasing fatigue cycles. However, the dislocation structure evolution would be changed in the low cycle fatigue under reducing amplitude. We could observe that the dislocation cells were broken to the loop patches in different form. Attest to the dislocation morphology was changed under reducing amplitude. After 10000 cycles at 0.4% strain amplitude, change the strain amplitude from 0.4% to 0.2%., we could observe that the dislocation cells were broken to the loop patches and vein structure. And after 100000 cycles under changed loading amplitude from 0.6% to 0.2%, large area of open domains and some loop patches can be observed.

To design a cyclone abatement system for particulate control, it is necessary to accurately estimate cyclone performance. In this cyclone study, new theoretical methods for computing travel distance, numbers of turns and cyclone pressure drop have been developed. The flow pattern and cyclone dimensions determine the travel distance in a cyclone. The number of turns was calculated based on this travel distance. The new theoretical analysis of cyclone pressure drop was tested against measured data at different inlet velocities and gave excellent agreement. The results show that cyclone pressure drop varies with the inlet velocity, but not with cyclone diameter. Particle motion in the cyclone outer vortex was analyzed to establish a force balance differential equation. Barth??s "static particle" theory, particle (with diameter of d50) collection probability is 50% when the forces acting on it are balanced, combined with the force balance equation was applied in the theoretical analyses for the models of cyclone cut-point and collection probability distribution in the cyclone outer vortex. Cyclone cut-points for different dusts were traced from measured cyclone overall collection efficiencies and the theoretical model for calculating cyclone overall efficiency. The cut-point correction models (K) for 1D3D and 2D2D cyclones were developed through regression fit from traced and theoretical cut-points. The regression results indicate that cut-points are more sensitive to mass median diameter (MMD) than to geometric standard deviation (GSD) of PSD. The theoretical overall efficiency model developed in this research can be used for cyclone total efficiency calculation with the corrected d50 and PSD. 1D3D and 2D2D cyclones were tested at Amarillo, Texas (an altitude of 1128 m / 3700 ft), to evaluate the effect of air density on cyclone performance. Two sets of inlet design velocities determined by the different air densities were used for the tests. Experimental results indicate that optimal cyclone design velocities, which are 16 m/s (3200 ft/min) for 1D3D cyclones and 15 m/s (3000 ft/min) for 2D2D cyclones, should be determined based on standard air density. It is important to consider the air density effect on cyclone performance in the design of cyclone abatement systems.

In this study, cell performance tests and measurements of the pressure drop in the anode flow channels of a micro methanol fuel cell (£gDMFC) were conducted. The effect of different operating parameters on £gDMFC performance was experimentally investigated for serpentine flow-field configuration. Experiments were conducted through a serious experiments with different operating conditions of temperature (40¡B60¡B70¡B80oC)¡Bmethanol concentration (0.5¡B1¡B1.5¡B2 M)¡Bchannel width (0.5¡B0.6¡B0.7¡B0.8¡B1¡B1.5¡B2 mm) and flow rate (10-20 sccm). Experimental results are presented in the form of polarization VI curves and PI curves under above operating conditions. The experimental results show that the pressure drop decrease with increasing current density. It has also shown that the pressure drop always increased with the methanol solution flow rates. The relationship between pressure drop and CO2 bubbles production rate would change with the current density increase. Finally, an optimal channel size of 700 £gm for the present £gDMFC could be obtained.

This dissertation reports on the discovery of a new method of patterning bacteria (Pseudomonas aeruginosa PAO1) on a surface using a drying sessile drop. This work identifies bacterial suspension age and the length of time mica is exposed to the laboratory atmosphere as the key parameters which impact the behavior of the sessile drop and the resulting residue. Possible origins of mica aging and bacterial suspension aging are discussed in light of the literature and the experimental conditions. The residue area and the fraction of the residue area on which substantial bacteria and salt deposits remained after the drying of the drop (fill-in fraction) were measured via analysis of optical micrographs. In general, smaller residues are more filled in. For fresh bacterial suspensions, and short mica exposure times, the residue covers the largest area and is characterized by rings formed during discrete depinning events as the solvent evaporates. As the exposure time increases and the mica surface slowly picks up contaminants from the atmosphere, the drop residue shrinks in size and bacteria are deposited in a regular cellular film in the interior of the drop residue. The fraction of the interior area covered by the cellular film is well correlated with the mica exposure time. For sufficiently aged bacterial suspensions, residues are small and more filled-in than residues formed from fresh suspensions on similarly aged mica. In addition, the interior deposition pattern transitions from a cellular film characteristic of fresh suspensions to a cracked carpet pattern for aged suspensions. Suspension aging related changes in the residues are attributed to accumulation of organic materials such as DNA, RNA, proteins, and other bacterial components in the suspension. The suspension aging process is also observed to be at least partially dependent on ventilation of the suspension during aging.

The design and analysis of drop test to investigate the behaviour of adhesive joints in automotive structures is performed. The drop test is simulated by FE software. The specimen geometry is based on Volvo Car Corp. drop test standard. In the drop test machine, a general beam structure is supporting all the parts. The machine includes a lifting system. The test is applied to a pre designed specimen, which will provide the information about adhesive joint strength.

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<p>The design and analysis of drop test to investigate the behaviour of adhesive joints in automotive structures is performed. The drop test is simulated by FE software. The specimen geometry is based on Volvo Car Corp. drop test standard.</p><p>In the drop test machine, a general beam structure is supporting all the parts. The machine includes a lifting system. The test is applied to a pre designed specimen, which will provide the information about adhesive joint strength.</p>

Thesis (M.S.)--University of Texas at Dallas, 2008. / Includes vita. Includes bibliographical references (leaves 86-87)