The heterogeneous and anisotropic nature of wood material creates additional design challenges not present with the use of other structural materials such as steel and aluminum. The natural variation in the physical properties of wood members requires that the specified strengths and resistances used for design calculations be based on the quantities measured for the fifth percentile of all wood materials tested. The result is that design may be unnecessarily conservative and subsequently inefficient. The same properties that cause uncertainty surrounding the physical properties of biological materials also create difficulty in applying non-destructive evaluation techniques. Strain measurement is one particular technique that is extremely valuable for materials of known and consistent stress-strain relationships, but whose usefulness is diminished when applied to biological materials. To demonstrate the need for more accurate strain measurement in light-framed structures, the predictive calculations and structural modelling of a post-framed building was compared to its demonstrated performance. The analysis did not adequately reflect the actual performance of the building, and it was determined that additional monitoring of light-framed buildings through systems such as strain measurement was required to gain a better understanding of the performance characteristics in order to optimize evaluation techniques. This project aimed to develop a system that accurately measures strain in dimensional lumber of different types, which in turn will enable researchers to enhance monitoring the performance of light-frame structures and optimize design analysis and structural modelling techniques. The development of a methodology that provides a practical means by which to perform in-situ testing of post-frame buildings and decreases the complexity of post-frame building monitoring will contribute to the advancement of design and analysis techniques. In the calibration phase of the project, metal foil resistance strain gages were mounted onto wooden specimens with dimensions of 5 x 13 x 40 mm, 5 x 40 x 100 mm, and 2 x 20 x 50 mm, and acrylic specimens with dimensions of 3 x 25 x 75 mm. These specimens were then subjected to loading in an ATS universal testing machine in the Physical Properties Lab at the University of Manitoba. Stress-strain curves were developed based upon the observed stress and strain levels. These calibrated gages were then mounted on to a 38 x 89 mm specimen of S-P-F dimensional lumber which represented a typical light-framed building material. This assembly was then subjected to a similar loading procedure as the calibrated gage and stress-strain curves were generated once again. The slopes of the stress-strain curves developed from the two phases of the project were compared to determine if a consistent correlation existed. The three sizes of wood specimens did not demonstrate a consistent correlation. However, the acrylic specimen demonstrated consistent correlation amongst two groups of three with correlation coefficients within a forty percent range in one group and within a nine percent range in the other group. This suggests that further experimental refinements could produce the desired results. / October 2007

To be able to ensure quality, efficiency and safety in nuclear reactors, non-destructive evaluations (NDE) are performed. The moulding technique, which has been studied in this project, is an NDE method used to verify surface breaking cracks at various objects in reactor vessels. The idea of moulding is to receive a copy of the replicated surface for microscopic analysis. Within forensic science the moulding technique is used at crime scenes to collect evidence and tie suspects to crimes. Underwater moulding, however, is a newly developed technique and WesDyne TRC is a pioneer in offering services within moulding for underwater purposes. This project was initiated by WesDyne TRC to further their knowledge within the moulding technology. In the project, studies have been made at three important parameters effect on cast quality using three different polymer compounds. Problems during moulding, such as crack detection failures and bubbles in the casts, raise the question whether the underwater moulding technique can be trusted to detect cracks. Results from the experiments led to a greater insight into the problem with receiving high quality casts during underwater moulding. Only if a satisfactory cast is made, the moulding method can be trusted to detect defects down to the detection target in both dry and wet environment. To increase the surface quality of underwater casts a suggestion for mould design and a recommended moulding method was developed. In addition, one of the polymer compounds approved for use, turned out not to be suitable for underwater moulding.

No description available.

In order to reach the economic scale, reduce unit cost and to enhance the international competitiveness, China Steel Cooperation constructed a subsidiary - Dragon Steel Cooperation, a 5-million-ton integrated steel plant nearby Taichung Harbor. Starting from iron-smelting, steel-making till steel-rolling, each step follows one another. If any of the steps occurs a problem, the whole production will be affected. The quality of the new construction is related to the life cycle of the equipments, the stability of the operation and the quality of the products. Further more, if the new construction is imperfect, there might be plenty of accidents, such as public safety, environment issues, protest from the inhabitants, etc. The influences could be huge. The main quality influences of the new construction work are low bids from the contractors, shoddy work and use inferior material during the construction, lack of control, welding problems, etc. According to the above main factors, we listed 20 secondary factors, e.g. bad financial situation, vicious competition, budget shortfalls, etc., and use analytical hierarchy process to find the relationship between them. In this thesis, there are in total 32 people have been interviewed, 8 of them are first-line supervisors (the up, middle and downstream of the steel plant, from steel-smelting plant, steel-rolling plant, public facility department to civil department.) Meanwhile, 10 senior executives are also interviewed; relevant literatures are used as related inference. Via this analysis, the most important factor of influencing the welding quality of new construction work is ¡§welding problem¡¨ with 0.297 rating point. Analyzing the third layer factors of low bids rating, the highest point is ¡§vicious competition¡¨ with 0.354. In shoddy work and use inferior material factor, ¡§changing subcontractor frequently¡¨ is the highest with 0.491 rating point. In false inspection, the ¡§progressing pressure¡¨ is the highest with 0.378 rating point. In welding problem, the ¡§construct without drawing¡¨ is the highest point with 0.371. In other factors, ¡§defected raw material¡¨ is the highest with 0.275 rating point. If the above problem solved, the welding quality in new construction work will improve tremendously. Keywords: non-destructive testing, quality of construction, new construction work, turnkey contractors, defect.

This study was to prepare nanoscale MgO using the homogeneous precipitation process and to investigate its destructive adsorption with dye wastewater of reactive black-5 and reactive blue-19. In addition, UV-vis Spectrophotometer, Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF/MS) and Gas Chromatograph/Mass Spectrometer (GC/MS) were used to analyze the intermediates resulting from destructive adsorption. Based on the results obtained, the destructive adsorption mechanisms for the treatment of dye wasterwater by nanoscale MgO were proposed in this study. In this work, the optimal operating conditions for nanoscale MgO synthesis were determined to be the following: (1) a chemical reaction time of 7 hr, (2) reaction temperature of 125¢J, (3) molar ratio of 9 for urea/MgCl2¡D6H2O, (4) water addition of 250 mL, (5) mixing intensity of 90 strokes per min, (6) calcination at 450¢J for 4 hr, (7) reflux time of 24 hr, (8) freeze-drying method, (9) two stage calcinations. Using these operating conditions one is able to prepare 2-D nanoscale MgO of hexagonal platelets with a thickness of 20-30 nm and BET surface area of 120-125 m2/g. The adsorption model of nanoscale MgO for RB-5 and RB-19 was fitted to the Langmuir equation and their adsorption capacity were 196.08 mg/g and 163.93 mg/g, respectively. Both of them were fitted to the pseudo-second-order kinetic model equation. The optimal operating conditions of nanoscale MgO for destructive adsorption of both dyes were determined to be the following: (1) an initial dye concentration of 1000 mg/L, (2) a nanoscale MgO dose of 15 g/L, (3) a vigorous mixing of 30 min, (4) no need of system pH adjustment. Under such conditions, chemical oxygen demand (COD) and American Dye Manufacturers Institute (ADMI) of RB-5 and RB-19 were lower than the textile effluent standards. According to the UV-vis spectrophotometer scanning results, the color removal of nanoscale MgO for RB-5 and RB-19 was good. At the same time, the absorbance of their second maximal peaks was decreased and some peaks were observed. Therefore, it proved that the model dyes were destroyed. Experimental results have shown that nanoscale MgO has a better performance of destructive adsorption on RB-5 than that of RB-19. This might be ascribed to the following reasons: (1) a greater molecular weight, (2) a longer molecule structure, (3) more sulfate ethyl sulfone groups for RB-5, and (4) a hard to be destroyed structure of anthraquinone for RB-19. The destructive adsorption of dye wastewater by nanoscale MgO presumably took place mainly on the surface active sites of nanoscale MgO, including anion/cation vacancies, superoxide anion, edge, corner, isolated OH, lattice bound OH and assiocited-OH groups. According to the results of MALDI-TOF/MS and GC/MS analysis, the relevant reaction mechanism for RB-5 could be divided into three stages: (1) adsorption and water-soluble groups exfoliation stage, (2) chromophor decomposition and decolorization stage, and (3) further degradation stage for light-color intermediates. On the other hand, the relevant reaction mechanism for RB-19 might involve only the adsorption and auxochrome exfoliation stage and chromophor decomposition and decolorization stage.

Plasma oxidation, an alternative to combustion, is shown to be a non-destructive method for obtaining radiocarbon dates on perishable organic artifacts. Electrically excited oxygen gently converts organic carbon to carbon dioxide. Radiocarbon measurements are then performed using accelerator mass spectrometry. Because only sub-milligram amounts of material are removed from an artifact over its exposed surface, no visible change in fragile materials has been observed, even under magnification. Materials in this study include: Third International Radiocarbon Intercomparison (TIRI) sample B (Belfast pine); Fourth International Radiocarbon Intercomparison (FIRI) optional samples; six different materials from a naturally mummified baby bundle from southwest Texas; and peyote from Shumla Caves, Texas, and Cuatro Ci??negas, Mexico. Continuing previous research in the Rowe laboratory, a primary application of plasma oxidation has been its use to date rock art at archaeological sites around the world. This dissertation includes dates for: Toca do Serrote da Bastiana, Brazil; Ignatievskaya Cave, Russia; partially buried megalithic monuments, Spain; Arnold/Tainter Cave, Wisconsin; and Little Lost River Cave No. 1, Idaho.

This study was to investigate the reaction behavior of nanoscale [Fe3O4]MgO and trichlorothylene (TCE) in aqueous solutions. In addition, effects of environmental variables on TCE removal from a simulated groundwater system were investigated. At first, two types of metal oxide composites containing both nanoscale Fe3O4 and MgO (designated H-[Fe3O4]MgO and S-[Fe3O4]MgO, respectively) were prepared. Then they were characterized and verified by various apparatuses and methods including X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, specific surface area measurements. Since the substrate of S-[Fe3O4]MgO with a molar ratio of Fe3O4/MgO = 1/5 (designated S1/5-[Fe3O4]MgO) had a much greater specific surface area than that of the substrate of S-[Fe3O4]MgO with a molar ratio of Fe3O4/MgO = 5/5 (designated S5/5-[Fe3O4]MgO), S1/5-[Fe3O4]MgO was selected as the model composite for the treatment of TCE in this study. Results of batch tests showed that S1/5-[Fe3O4]MgO had the best treatment performance among various metal oxides and their composites. For an initial TCE concentration of 10 mg/L, however, only 45% removal could be achieved by 5.0 g/L of dispersed S1/5-[Fe3O4]MgO. Nevertheless, a greater removal efficiency could be obtained for a higher initial TCE concentration in a simulated groundwater system. Test results also showed that a lower temperature and higher pH would retard the relevant reaction rates in TCE removal. In the simulated groundwater system employed in this work, the existence of humic acid (< 10 mg/L) played an insignificant role in affecting the TCE removal. Analysis of TCE adsorption on S1/5-[Fe3O4]MgO in aqueous solution indicated that a Langmuir-type of chemical adsorption would have a better fit. Results of gas chromatography further showed the existence of small to trace amounts of TCE degradation products including cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, vinyl chloride, ethene and methane, etc. Thus, the relevant reaction mechanisms and pathways for the destructive adsorption were proposed.

Thesis (M.S.)--Mechanical Engineering, Georgia Institute of Technology, 2004. / Berthelot, Committee Chair; Lynch, Committee Member; Jacobs, Committee Member. Includes bibliographical references (leaves 111-113).

Thesis (M. Phil.)--University of Hong Kong, 1981.

The proposed study explores the feasibility of detecting and quantifying corrosion and delamination (physical separation) at the interface between reinforcing steel bars and concrete using ultrasonic guided waves. The problem of corrosion of the reinforcing steel in structures has increased significantly in recent years. The emergence of this type of concrete deterioration, which was first observed in marine structures and chemical manufacturing plants, coincided with the increased applications of deicing salts (sodium and calcium chlorides) to roads and bridges during winter months in those states where ice and snow are of major concern. Concrete is strengthened by the inclusion of the reinforcement steel such as deformed or corrugated steel bars. Bonding between the two materials plays a vital role in maximizing performance capacity of the structural members. Durability of the structure is of concern when it is exposed to aggressive environments. Corrosion of reinforcing steel has led to premature deterioration of many concrete members before their design life is attained. It is therefore, important to be able to detect and measure the level of corrosion in reinforcing steel or delamination at the interface. The development and implementation of damage detection strategies, and the continuous health assessment of concrete structures then become a matter of utmost importance. The ultimate goal of this research is to develop a nondestructive testing technique to quantify the amount of corrosion in the reinforcing steel. The guided mechanical wave approach has been explored towards the development of such methodology. The use of an embedded ultrasonic network for monitoring corrosion in real structures is feasible due to its simplicity. The ultrasonic waves, specifically cylindrical guided waves can propagate a long distance along the reinforcing steel bars and are found to be sensitive to the interface conditions between steel bars and concrete. Ultrasonic transducers are used to launch and detect cylindrical guided waves along the steel bar.In this dissertation, in-situ corrosion monitoring technique for reinforced concrete is developed based on two methods - 1) variation of signal strength and 2) the time-of-flight (TOF) variations as the corroded member is loaded transversely. This is the first attempt ever to monitor corrosion inside concrete by measuring the change in the time of flight of guided waves along reinforcing bars as the concrete beam is subjected to bending. Advantages of corrosion monitoring by TOF change are discussed in the dissertation.