Publications

The flexural performance of an RC beam can be improved using the near-surface mounted (NSM) FRP strengthening technique. In such FRP-strengthened RC beams, debonding failure at the two bar ends may occur due to high interaction forces in the bar-end regions between the RC beam and the FRP bars. This paper presents a theoretical investigation into these interaction forces in RC beams strengthened with NSM FRP rectangular bars. By introducing and defining two interfacial stiffness parameters, an analytical solution for the tangential and the normal interaction forces is first obtained as an extension of the analytical solution developed by Smith and Teng [1] for beams strengthened with an externally bonded plate. The accuracy of the analytical solution is verified with predictions from a 3-D linear elastic finite element model. Disciplines Engineering | Science and Technology Studies Publication Details Zhang, S. S. & Teng, J. G. (2012). Analytical solution for interaction forces in RC beams strengthened with NSM rectangular bars. Proceedings, 6th International Conference on FRP Composites in Civil Engineering (pp. 1-6). This conference paper is available at Research Online: http://ro.uow.edu.au/eispapers/4952

The effect of low-NOx combustion technologies on particulate emissions from coal-fired boilers is much less known. It is investigated in this work by experiments on two 200 MW coal-fired boilers, one with low-NOx combustion and the other with conventional combustion. Collection of particulate matter with an aerodynamic diameter of up to 10 μm (PM10) was carried out at the inlet of the electrostatic precipitators of both boilers. The particulates were classified into 13 size fractions by a low-pressure impactor. Their emissions and size distributions were obtained. Particle chemical composition was characterized by an X-ray fluorescence analyzer. The data show that low-NOx combustion results in higher concentrations of total suspended particulate (TSP) and PM10 but lower concentrations of PM2.5 and PM1. The size distribution of PM10 from both boilers shows a trimodal feature that is not significantly affected by low-NOx combustion. However, it is found for the first time that the size distribution of PM10 from low-NOx combustion shifts to a larger size compared to that from conventional combustion. The size distributions of Al, Si, S, and Ca in the <10 μm size range suggest three particle modes that are formed by different mechanisms. The inconsistency in the literature as to whether there is a relationship between PM1 and NOx is thought to be due to the fact that PM1 is not totally formed by the vaporization and condensation mechanism. The preliminary data presented in this work suggest that, for the test cases, there seems to be a positive correlation between NOx and PM0.1 that is formed by solid–vapor–particle processes.

To examine the real effects of typical inorganics on the emission behavior of PM10 during coal combustion and explore the interactions between the typical vaporized and refractory inorganics, Na-, Si-, and (Na+Si)-loaded coals prepared from the ash-removed PDS bituminous coal and ZD subbituminous coal were combusted in a high temperature drop-tube furnace (DTF) at 1500 °C in air. The produced inorganic PM10 and PM2.5 were collected and characterized. The experimentally measured PM emission results from the combustion of the (Na+Si)-loaded coals were compared with the calculated results that are the sum of PM emitted from the combustion of the Na- and Si-loaded coals. The calculated yields of PM0.3 of two studied coals are higher than the experimental ones, while the calculated yields of PM0.3-2.5 are lower. The experimental yield of PM0.3-2.5 is mainly enhanced by the sodium condensing heterogeneously on fine quartz particles, while the sodium would contribute to PM0.3 homogeneously, leading to the higher calculated result derived from the Na-loaded coal. Na is prevalent in only submicron particles for both the Na- and the (Na+Si)-loaded coals. The homogeneous partitioning ratio of Na is unaffected by the loading of quartz, but the heterogeneous partitioning ratio is affected by the quartz particles on which vaporized Na can condense into particles larger than 0.2 μm. Si presents similar distribution characteristics of trimodal for both the Si- and the (Na+Si)-loaded coal. The partitioning of Si in PM0.3 appears to be affected by Na due to the higher partitioning ratio of the (Na+Si)-loaded coal. The apparent catalytic effects of Na species on the combustion reactivity should beneficiate the local reducing atmosphere, and thereby promote the reduction of SiO2 to SiO, which is easily vaporized to contribute to PM0.3 for the (Na+Si)-loaded coal.

The analytical and experiment research of In-Vessel Corium Retention (IVR) in the Chinese Pressurized-water Reactor 1000 MWe (CPR1000) are introduced. The IVR research consists of preliminary phase and detailed phase. The analysis of thermal failure, structural failure and penetration failure of Reactor Pressure Vessel (RPV) and the experimental research of External Reactor Vessel Cooling (ERVC) are performed at preliminary phase. Analysis results show that the RPV failure is the dominated by thermal failure mode and the probability of the thermal failure is very low. Test results show that the IVR success probability for CPR1000 is about 99% if the Critical Heat Flux (CHF) of CPR1000 is the same as that of AP600. Further works, including the ERVC enhancement design, the CHF test of the RPV outer wall and the recalculation of the IVR success probability for CPR1000, will be performed at detailed phase in the near future.

With the resurgence of drugs with covalent binding mechanisms, much attention has been paid to docking methods for the discovery of targeted covalent inhibitors. The existence of many available covalent docking tools has inspired development of a systematic and objective procedure and criteria with which to evaluate these programs. In order to find a tool appropriate to studies of a covalently binding system, protocols and criteria are proposed for protein-ligand covalent docking studies. This paper consists of three sections: (1) curating a standard data set to evaluate covalent docking tools objectively; (2) establishing criteria to measure the performance of a tool applied for docking ligands into a complex system; and (3) creating a protocol to evaluate and select covalent binding tools. The protocols were applied to evaluate four covalent docking tools (MOE, GOLD, CovDock, and ICM-Pro) and parameters affecting covalent docking performance were investigated.

This paper is concerned with the development of an accurate bond strength model for carbon-fiber-reinforced polymer (CFRP) strips near-surface mounted (NSM) to concrete where debonding occurs as a result of cohesion failure in the adjacent concrete. Based on an existing analytical solution and the fracture energy equation recently developed by the authors, a bond strength equation is first proposed for NSM CFRP strip-to-concrete bonded joints with a sufficient bond length (i.e., the bond length exceeds a threshold value referred to as the effective bond length). The influence of an insufficient bond length on the bond strength is next examined through a parametric study conducted using a beam-spring numerical model in which a bond-slip model recently proposed by the authors is incorporated. Based on the numerical results, expressions are formulated for the effective bond length and the bond-strength reduction factor for insufficient bond lengths. The combination of these equations leads to a new bond strength model for NSM CFRP strip-to-concrete bonded joints. The predictions of the proposed bond strength model are compared with the results of 51 test specimens collected from seven existing studies and the predictions of the only existing bond strength model for such joints. These comparisons indicate that the proposed model is accurate and superior to the existing bond strength model, particularly for joints with insufficient bond lengths. The proposed bond strength model, because of its accuracy and simplicity, can be readily incorporated in design codes and guidelines.

Fibre-reinforced polymer–concrete–steel hybrid multi-tube concrete columns are a new form of columns recently proposed at the University of Wollongong. An multi-tube concrete column consists of an external fibre-reinforced polymer tube and a number of circular internal steel tubes, with the space inside all the tubes filled with concrete. This article presents the first ever experimental study on square multi-tube concrete columns. The experimental program included a total of 14 stub column specimens tested under axial compression, with the test variables being the thickness of the external fibre-reinforced polymer tube, and the dimensions and configuration of the internal steel tubes. The test results demonstrated that the concrete in the square multi-tube concrete columns was very effectively confined by the multiple tubes, and that the buckling of the internal steel tubes was completely prevented, leading to full structural utilization of the materials and a very ductile response. The test results also showed that the behaviour of the concrete in the square multi-tube concrete columns was significantly superior to that in the corresponding square concrete-filled fibre-reinforced polymer tubes, in terms of the compressive strength, the ultimate axial strain and the stiffness of the second branch of the stress–strain curve. A simple analytical model proposed for the axial load-axial strain curve of square multi-tube concrete columns is also presented and is shown to provide reasonable and conservative predictions of the test results.