Development of entertainment balloon robot system for an indoor event venue

This project revolves around the combination of different state-of-the-art concepts to create balloon robots which can be used for entertainment purposes. The goal is having multiple robots perform a choreographed flight on preset paths to make use of the “dead space” over the crowd of an event, either as part of the show or displaying information and advertisements. As the balloon is flying on a defined trajectory, a tracking system for its position is needed. For this purpose, several infrared cameras monitor the position of a marker attached to the balloon. The main challenge is overcoming the instabilities of the system to ensure a smooth and precise flight, resulting from the balloons structure: the balloon is filled with helium to counteract the forces of gravity and, therefore, minimize the work needed to keep its momentum. Finding a way to achieve this optimization and the precision mentioned beforehand is the task that we will present and solve in this paper.     

Effect of supercritical water on upgrading reaction of oil sand bitumen

The advantages of supercritical water (SCW) as a reaction medium for upgrading oil sand bitumen were investigated through a comprehensive analysis of the output product, which includes gaseous products, middle distillate, distillation residue, and coke. Canadian oil sand bitumen mined by the steam assisted gravity drainage method was treated in an autoclave at 420-450 °C and 20-30 MPa for up to 120 min with three kinds of reaction media: SCW, high-pressure nitrogen, and supercritical toluene. The yields of gaseous products indicated that a very small amount of water was involved in the upgrading reaction. The analytical results of the middle distillate fractions were almost the same using water and nitrogen at 450 °C. The distillation residues produced in SCW had lower molecular weight distributions, lower H/C atomic ratios, higher aromaticities, and consequently more condensed structures compared to those produced in nitrogen. The coke produced using SCW also had lower H/C values and higher aromaticities. Judging from all the analytical results, the upgrading of bitumen by SCW reaction was primarily considered to be physical in nature. As a result, it is possible to highly disperse the heavy fractions by SCW. This dispersion effect of SCW led to intramolecular dehydrogenation of the heavier component and prevention of recombination reactions, and consequently gave the highest conversion.     

Comparison of single-walled carbon nanotube growth from Fe and Ni nanoparticles using quantum chemical molecular dynamics methods

Metal-catalyzed SWCNT growth has been modeled using quantum chemical molecular dynamics (QM/MD) in conjunction with feeding of carbon atoms to C₄₀-Fe₅₅ and C₄₀-Ni₅₅ model complexes at 1500 K. The rate of Fe₅₅-catalyzed SWCNT growth determined in this work was 19% slower than the Fe₃₈-catalyzed growth rate. Conversely, Ni₅₅-catalyzed SWCNT growth exhibited a growth rate 69% larger than of Fe₅₅-catalyzed SWCNT growth, a fact consistent with excellent performance of Ni in laser evaporation and carbon-arc experiments. Ni₅₅-catalyzed growth was preceded by the formation of extended polyyne chains at the base of the SWCNT, and so differed fundamentally from Fe₅₅-catalyzed growth. These polyyne chains usually persisted for 10-30 ps. Subsequent polyyne ring condensation resulted in carbon polygon addition at the SWCNT base. The relative stabilities of the C_n carbon cluster moieties on the Fe₅₅ and Ni₅₅ surfaces were consistent with the relative strengths of the Fe-C, Ni-C and C-C interactions. The presence of smaller carbon moieties on the Fe₅₅ surface led to the dissemination of surface iron atoms, and subsequent diffusion of short C_n units through the subsurface region of the catalyst particle. Conversely, the Ni₅₅ catalyst particle was observed to be more stable, remaining intact to a greater extent.     

Al-Si合金宏观偏析、凝固组织演变的元胞自动机-控制容积法耦合模拟

建立凝固过程中宏观流动、传热、溶质传输与微观形核、生长过程双向耦合数学模型,并针对Al-Si二元合金凝固过程进行二维元胞自动机控制容积积分法(CA FV)耦合模拟。模型反映了流场下晶体逆流生长特性,考虑了温降导致的形核和生长以及形核和生长引起的固相分率变化对宏观场的影响,能预测凝固过程中再辉和晶间偏析等现象,反映合金液流动对合金的溶质分布以及凝固组织形貌的作用规律。与仅宏观传输模拟结果和无流动影响的模拟结果进行了对比,验证了耦合模型的优越性。同时考察了铸型尺寸对凝固组织形貌的影响。     

Characterization of bagasse‐rind particleboard bonded with chitosan

The development of high‐performance non‐wood lignocellulosic board without using synthetic adhesives derived from fossils resources is very important for the future. In this study, the characterization of bagasse particleboard bonded with chitosan was investigated. The 4 wt % chitosan‐acetic acid solution was sprayed onto bagasse rind particles at a 2–10 wt % chitosan solid content based on the dry particles. Particleboards with target densities of 0.75 and 0.9 g/cm³ were manufactured using a steam‐injection press. The steam pressure and total pressing time were 1 MPa (180°C) and 7 min, respectively. The addition of 2–4 wt % of chitosan was the most effective in the bending properties. The high‐density board bonded with a 4 wt % addition of chitosan showed a good result in the internal bond strength test. Furthermore, the board had favorable dimensional stability in dilute acetic acid as well as in a cyclic accelerated aging test. Judging from the analysis of bagasse extract‐added chitosan films, it was suggested that chitosan reacted with extract from bagasse during steam‐injection pressing. The reaction seemed to contribute to the board's good resistance to dilute acid. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Process metallurgy design of aluminum alloy sheet rolling by using two-scale finite element analysis and optimization algorithm

Recently, the asymmetric rolling (ASR) process was applied to the aluminum alloy sheet generation to control the micro-crystal structure in order to improve the formability and the strength. Until now, many experimental and numerical studies of ASR process have been carried out, but these schemes have not enough capability to predict the texture evolution at the micro-scale and the sheet formability at the macro-scale. In this study, we develop a process metallurgy design code to analyze and optimize the sheet rolling process. At first, our dynamic-explicit crystallographic homogenized elasto/viscoplastic finite element (two-scale FE) code was applied to analyze ASR sheet deformation and optimized ASR process to generate a high formability sheet metal by employing the response surface method. A texture evolution of ASR sheet metal under an optimum process condition was compared with the experimental results, and the availability of our design code was confirmed. Next, an initial texture for the symmetrical warm rolling was optimized to generate a better formability sheet metal. Consequently, our two-scale FE code combined with the optimization algorithm was verified as a comprehensive tool in the process metallurgy design to predict plastic induced texture evolutions and optimize a rolling process and an initial texture for a high formability sheet generation.     

Estimating illuminant color based on luminance balance of surfaces

To accomplish color constancy the illuminant color needs to be discounted from the light reflected from surfaces. Some strategies for discounting the illuminant color use statistics of luminance and chromaticity distribution in natural scenes. In this study we showed whether color constancy exploits the potential cue that was provided by the luminance balance of differently colored surfaces. In our experiments we used six colors: bright and dim red, green, and blue, as surrounding stimulus colors. In most cases, bright colors were set to be optimal colors. They were arranged among 60 hexagonal elements in close-packed structure. The center element served as the test stimulus. The observer adjusted the chromaticity of the test stimulus to obtain a perceptually achromatic surface. We used simulated black body radiations of 3000 (or 4000), 6500, and 20000 K as test illuminants. The results showed that the luminance balance of surfaces with no chromaticity shift had clear effects on the observer's achromatic setting, which was consistent with our hypothesis on estimating the scene illuminant based on optimal colors.     

High-velocity impact damage behavior of plain-woven SiC/SiC composites after thermal loading

This study investigates characteristics of foreign-object damage in plain-woven SiC/SiC composites after thermal loading. High-speed impact tests were conducted on virgin specimens, thermally exposed specimens, and thermally shocked specimens, in which the maximum temperature during thermal loading was 600 °C or 1000 °C. An oxide layer was generated on the specimen surface by thermal loading at 1000 °C. Damaged areas on the front and back surfaces induced by particle impact were independent of thermal loading. However, in specimens thermally loaded at 1000 °C, brittle failure, i.e. cone cracking without fiber pull-out, occurred due to oxidation of the fiber/matrix interfaces, and the ballistic limit velocity significantly decreased. Finally, the ballistic limit is predicted using static strength properties, and the effect of thermal loading on impact resistance is discussed.     

Paper-based diagnostic devices for evaluating the quality of human sperm

Male infertility, which amounts to half of all infertility cases, is a serious problem worldwide. The percentage of fertility-related patients in sub-Saharan African countries is higher than that for the developed countries. In low-resource countries, examination of sperm characteristics for male infertility cannot be undertaken because of poor clinical access. To evaluate male fertility in assisted reproductive medicine laboratories, the numbers of motile human sperm, the degree of sperm motility, and sperm morphology have been commonly analyzed using a microscope. It is challenging to monitor the health status of human sperm in resource-limited or remote settings for two primary reasons: (1) high capital cost (equipment for currently accepted procedural standard), and (2) complexity of the currently accepted procedural standard used to simultaneously measure human sperm concentration and motility by skillful embryologists. Determining the health status of human sperm in order to evaluate fertilization capacity using various types of low-cost, easy-to-use, and rapid devices (or systems) is a longstanding but interesting biotechnologically relevant issue in various scientific communities such as male reproduction. Furthering such efforts will inherently influence birth rate in both developed and developing nations. We have demonstrated an inexpensive but robust and easy-to-handle device for monitoring the health status of human sperm made by patterning a piece of paper and measuring the activity of a specific enzyme—a simple and elegant solution. After applying semen to the hydrophilic center circle of our patterned paper, a thiazine assay can be used to suggest sperm concentration in semen, and a tetrazolium-based colorimetric assay (MTT assay) data can be used to help estimate the percentage of motile human sperm (sperm motility) in semen based on the character that motile human sperm moved in and on the paper. Using this paper-based device, we can evaluate fertility levels without consulting doctors and use our assay to compare results with World Health Organization (WHO) reference values for sperm concentration (>2×10⁷) and motility (>50 %). The duration and cost of one entire test are 30 min and 0.1 USD, respectively. We believe that this paper-based assay system would be useful for fertility checks based on WHO references, without need of a microscope, at home. Using this assay method, males in developed or developing countries who are reluctant or unable to consult assisted reproductive technologies clinics can self-analyze their sperm characteristics. We further note that our approach adheres to WHO regulations, especially in regard to in vitro diagnostic device performance with an associated diagnostic algorithm to enhance diagnostic accuracy (compared with just one diagnostic output), and we wish to emphasize that our research could significantly advance a broad range of diagnostic developments including paper-based diagnostic devices, in vitro diagnostic devices, and diagnosis of other diseases in various divisions of translational medicine. These results, we believe, will be of interest to a wide scientific audience working in materials science (biomaterials), chemistry (analytical and clinical), lab-on-a-chip technologies (the development of diagnostic tools), reproductive medicine, bioengineering, and translational medicine.     

Detection of small cracks in the chain of a trolley conveyor with an infrared camera

This paper describes the development of a non-destructive inspection method for cracks in a trolley conveyor chain, using a high-frequency electric current heater and an infrared radiation camera. This method is based on the idea that cracks affect heat conduction in the chain. When the chain is heated properly with the heater, variations in the heat conduction can be detected by monitoring the surface temperature of the chain with the infrared camera. The effectiveness of the proposed method is shown by a numerical analysis of the heat conduction in the chain. It is confirmed that the method is applicable to the chain which consists of portions with high and low emissivity, and that it is not affected by oil mixed with wear debris on the chain surface or by the operation speed of the conveyor.