Strength Assessment of MiniBarsTM Reinforced Concrete Structures with Low Heat Cement

MiniBarsTM is a kind of high-performance composite macrofibre made of BFRP. It is designed to improve the flexural tensile strength and post-cracking (residual) strength of the concrete. Moreover, it has a reputation for corrosion-free and zero conductivity. This thesis focused on the influence of the MiniBarsTM fiber volume fraction on the behavior of the concrete under compressive and tensile stress. A compression test and 3-point bending test were conducted on the specimens containing 0%, 0.5%, and 1% of fiber by volume. MiniBarsTM fiber volume fraction had a minor effect on the compressive strength of the concrete. In comparison with the plain concrete, the compressive strength decreased by 0.1% and 5.6% respectively for MiniBarsTM dosage of 0.5% and 1% after curing for 28 days. However, the MiniBarsTM fiber did improve the failure of the concrete. Fewer spalling and narrower cracks occurred in the cubes reinforced by MiniBarsTM fiber. No remarkable change was observed in the flexural tensile strength of the concrete due to the fiber addition. But the test results showed that the addition of MiniBarsTM fiber significantly improved the behavior of the concrete after flexural cracking. The specimens revealed a ductile response to the tensile stress. The residual tensile strength of the MiniBarsTM reinforced concrete in ULS and SLS went up by 110% and 150% respectively after when the added fiber volume fraction increased from 0.5% to 1.0%. It was mainly due to the bridging action and the pulling-out resistance of the MiniBarsTM

Investigation of ejector re-compression absorption refrigeration cycle

This thesis describes a theoretical and experimental investigation of the ejector re-compression lithium bromide absorption refrigeration cycle. In this novel cycle, a steam ejector is used to enhance the concentration process by compressing the vapour to a state that it can be used to re-heat the solution from where it was evolved. Since this cycle recovers the heat otherwise wasted in a conventional absorption cycle, the energy performance of the cycle is improved. The theoretical study shows that the improvement of the efficiency is proportional to the performance of the steam ejector. A COP of 1.013 was achieved from the experiment in this investigation. The novel cycle does not only improve the energy efficiency but also avoids the corrosion that will happen when high temperature heat sources are used to drive a lithium bromide absorption refrigerator. The steam ejector in the novel cycle acts as an efficient temperature converter in acceptance of different temperature heat sources, which reduces the energy loss when the temperature difference between the solution and the heat source is big. Therefore, the solution temperature can be set to a low level while the heat source temperature is high. This is significant to avoid the corrosion of lithium bromide solution at high temperature. Furthermore, the construction of the machine based on the novel cycle is simpler than that based on the conventional double-effect cycle. This refrigerator will be more reliable and have a lower initial capital cost. The cycle was investigated comprehensively in this thesis. In the theoretical study, a mathematical model for this novel cycle was established. The theoretical study reveals the operation characteristics and the factors that affect the energy efficiency of the cycle as well as how to design a refrigerator based on the novel cycle. In the experimental study, a concept-approved refrigerator was manufactured and tested. The part-load performance of the novel cycle was investigated from the experiment. The theoretical results had a good agreement with the experimental ones. NB. This ethesis has been created by scanning the typescript original and contains some inaccuracies. In case of difficulty, please refer to the original text

Generating Handwritten Chinese Characters using CycleGAN

Handwriting of Chinese has long been an important skill in East Asia. However, automatic generation of handwritten Chinese characters poses a great challenge due to the large number of characters. Various machine learning techniques have been used to recognize Chinese characters, but few works have studied the handwritten Chinese character generation problem, especially with unpaired training data. In this work, we formulate the Chinese handwritten character generation as a problem that learns a mapping from an existing printed font to a personalized handwritten style. We further propose DenseNet CycleGAN to generate Chinese handwritten characters. Our method is applied not only to commonly used Chinese characters but also to calligraphy work with aesthetic values. Furthermore, we propose content accuracy and style discrepancy as the evaluation metrics to assess the quality of the handwritten characters generated. We then use our proposed metrics to evaluate the generated characters from CASIA dataset as well as our newly introduced Lanting calligraphy dataset.Comment: Accepted at WACV 201

An experimental investigation of a micro-tubular SOFC membrane-separated liquid desiccant dehumidification and cooling tri-generation system

This paper reports the results of experimental work carried out on a micro-tubular solid oxide fuel cell tri-generation systemthat uses the waste heat from the fuel cell for dehumidification and cooling though the integration of an open cycle liquid desiccant dehumidification and cooling system. The experimental results demonstrate regeneration of the potassium formate solution using the thermal output from the SOFC in the first of its kind tri-generation system. Optimisation has shown that a 2.2L.min-1 regenerator desiccant volumetric flow facilitates best performance.When integrated with the micro-SOFC, the open cycle desiccant system demonstrates a COP of approaching 0.7, an encouraging value for a waste heat driven cooling system of this capacity. A tri-generation performance analysis is presented which serves to demonstrate the novel system operating in a building. The system achieved an electrical efficiency of 11% and regeneration efficiency of approximately 37%. The electrical efficiency is lower than that predicted by the company supplying the micro-tubular SOFC, because the unit suffered sulphur poisoning during preliminary tests. The electrical power output decreased from 250W to 150W, which reduced the electrical efficiency from around 18% to 11% and the overall efficiency from approximately 45% to just over 37%. Low temperature (33-36°C) regeneration was demonstrated

Investigation of ejector re-compression absorption refrigeration cycle

This thesis describes a theoretical and experimental investigation of the ejector re-compression lithium bromide absorption refrigeration cycle. In this novel cycle, a steam ejector is used to enhance the concentration process by compressing the vapour to a state that it can be used to re-heat the solution from where it was evolved. Since this cycle recovers the heat otherwise wasted in a conventional absorption cycle, the energy performance of the cycle is improved. The theoretical study shows that the improvement of the efficiency is proportional to the performance of the steam ejector. A COP of 1.013 was achieved from the experiment in this investigation. The novel cycle does not only improve the energy efficiency but also avoids the corrosion that will happen when high temperature heat sources are used to drive a lithium bromide absorption refrigerator. The steam ejector in the novel cycle acts as an efficient temperature converter in acceptance of different temperature heat sources, which reduces the energy loss when the temperature difference between the solution and the heat source is big. Therefore, the solution temperature can be set to a low level while the heat source temperature is high. This is significant to avoid the corrosion of lithium bromide solution at high temperature. Furthermore, the construction of the machine based on the novel cycle is simpler than that based on the conventional double-effect cycle. This refrigerator will be more reliable and have a lower initial capital cost. The cycle was investigated comprehensively in this thesis. In the theoretical study, a mathematical model for this novel cycle was established. The theoretical study reveals the operation characteristics and the factors that affect the energy efficiency of the cycle as well as how to design a refrigerator based on the novel cycle. In the experimental study, a concept-approved refrigerator was manufactured and tested. The part-load performance of the novel cycle was investigated from the experiment. The theoretical results had a good agreement with the experimental ones. NB. This ethesis has been created by scanning the typescript original and contains some inaccuracies. In case of difficulty, please refer to the original text

Investigate the plasmonic enhanced solar photothermal effect of gold nanorod nanofilm

Gold nanospheres (Au NSs) and gold nanorods (Au NRs) are traditional noble metal plasmonic nanomaterials. Particularly, Au NRs with tunable longitudinal plasmon resonance from visible to the near infrared (NIR) range were suitable for high efficient photothermal applications due to extended light receiving range. In this work, we synthesized Au NRs and Au NSs of similar volume, and subsequently developed them into Au NR/PVDF and Au NS/PVDF nanofilm, both of which exhibited excellent solar photothermal performance evaluated by solar photothermal experiments. We found that Au NR/PVDF nanofilm showed higher solar photothermal performance than Au NS/PVDF nanofilm. Through detailed analysis, such as morphological characterization, optical measurement, and finite element method (FEM) modeling, we found that the plasmonic coupling effects inside the aggregated Au NRs nanoclusters contributed to the spectral blue-shifts and intensified photothermal performance. Compare to Au NS/PVDF nanofilms, Au NR/PVDF nanofilm exhibited higher efficient light-to-heat conversion rate, because of the extended light receiving range and high absorbance, as the result of strong plasmonic interactions inside nanoclusters, which was further validated by monochromatic laser photothermal experiments and FEM simulations. Our work proved that the Au NRs have huge potential for plasmonic solar photothermal applications, and are envisioned for novel plasmonic applications

Multiple flat bands and localized states in photonic super-Kagome lattices

We demonstrate multiple flat bands and compact localized states (CLSs) in a photonic super-Kagome lattice (SKL) that exhibits coexistence of singular and nonsingular flat bands within its unique band structure. Specifically, we find that the upper two flat bands of an SKL are singular - characterized by singularities due to band touching with their neighboring dispersive bands at the Brillouin zone center. Conversely, the lower three degenerate flat bands are nonsingular, and remain spectrally isolated from other dispersive bands. The existence of such two distinct types of flat bands is experimentally demonstrated by observing stable evolution of the CLSs with various geometrical shapes in a laser-written SKL. We also discuss the classification of the flat bands in momentum space, using band-touching singularities of the Bloch wave functions. Furthermore, we validate this classification in real space based on unit cell occupancy of the CLSs in a single SKL plaquette. These results may provide insights for the study of flatband transport, dynamics, and nontrivial topological phenomena in other relevant systems.Comment: 5 pages,4 figure