Muroran-IT Academic Resource Archive
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2段縦型撹拌槽における交換流量
Get PDF2つのタービン翼を備えた2段縦型撹拌槽の交換流量におよぼすリング状仕切板の開孔率，撹拌速度の影響を実験的に検討した．翼径Diは槽径DTの1/2とした．交換流量Qは撹拌速度n，開孔率Arに比例して大きくなった．2段縦型撹拌槽の場合でも，修正無次元交換流量Q/（nDi3Ar）と撹拌レイノルズ数の関係は3段縦型撹拌槽の場合と同じであった．また，修正無次元交換流量Q/（nDi3Ar）は2段縦型撹拌槽の槽高さの−1.7乗に比例することがわかった．The effects of stirring speed n and opening ratio of a ring-shaped partition plate Ar, on the exchange rate of vertical vessels with two multiple impellers Q were experimentally investigated. The impeller diameter Di was one-half of the vessel diameter DT. The exchange rate Q was proportionally greater than the stirring speed of impellers n and the opening ratio of the ring-type partition plate Ar. In the case of two-stage vertical stirred vessel, the relationship between the modified dimensionless exchange rate Q/(nDi3Ar) and the agitated Reynolds number NRe was the same as in the case of the three-stage vertical stirred vessel. The modified dimensionless exchange rate Q/(nDi3Ar) was found to be proportional to the height of the two-stage vertical stirred vessel at the power of −1.7.journal articl
Detecting and Visualizing Stops in Dance Training by Neural Network Based on Velocity and Acceleration
Get PDFVarious genres of dance, such as Yosakoi Soran, have contributed to the health of many people and contributed to their sense of belonging to a community. However, due to the effects of COVID-19, various face-to-face activities have been restricted and group dance practice has become difficult. Hence, there is a need to facilitate remote dance practice. In this paper, we propose a system for detecting and visualizing the very important dance motions known as stops. We measure dance movements by motion capture and calculate the features of each movement based on velocity and acceleration. Using a neural network to learn motion features, the system detects stops and visualizes them using a human-like 3D model. In an experiment using dance data, the proposed method obtained highly accurate stop detection results and demonstrated its effectiveness as an information and communication technology support for remote group dance practice.journal articl
One‐parameter families of Legendre curves and plane line congruences
Get PDFFamilies of curves in the Euclidean plane naturally contain singular curves, where the frame of classical differential geometry does not work well. We introduce the notions of one-parameter family of Legendre curves in the Euclidean plane, congruent equivalence and curvature. Especially, a one-parameter family of Legendre curves can contain singular curves, and is determined by the curvature up to congruence. We also give properties of one-parameter families of Legendre curves. As applications, we give a relation between one-parameter families of Legendre curves and Legendre surfaces. Moreover, we study plane line congruences (one-parameter families of lines in plane) in terms of the curvatures as one-parameter families of Legendre curves.journal articl
Topology Optimal Design of NRD Guide Devices Using Function Expansion Method and Evolutionary Approaches
Get PDFIn order to increase communication capacity, the use of millimeter-wave and terahertz-wave bands are being actively explored. Non-radiative dielectric waveguide known as NRD guide is one of promising platform of millimeter-wave integrated circuits thanks to its nonradiative and low loss nature. In order to develop millimeter wave circuits with various functions, various circuit components have to be efficiently designed to meet requirements from application side. In this paper, for efficient design of NRD guide devices, we develop a topology optimal design technique based on function-expansion-method which can express arbitrary structure with arbitrary geometric topology. In the present approach, recently developed two-dimensional full-vectorial finite element method (2D-FVFEM) for NRD guide devices is employed to improve computational efficiency and several evolutionary approaches, which do not require appropriate initial structure depending on a given design problem, are used to optimize design variables, thus, NRD guide devices having desired functions are efficiently obtained without requiring designer’s special knowledge.journal articl
Review of the Developments of Bacterial Medium-Chain-Length Polyhydroxyalkanoates (mcl-PHAs)
Get PDFSynthetic plastics derived from fossil fuels—such as polyethylene, polypropylene, polyvinyl chloride, and polystyrene—are non-degradable. A large amount of plastic waste enters landfills and pollutes the environment. Hence, there is an urgent need to produce biodegradable plastics such as polyhydroxyalkanoates (PHAs). PHAs have garnered increasing interest as replaceable materials to conventional plastics due to their broad applicability in various purposes such as food packaging, agriculture, tissue-engineering scaffolds, and drug delivery. Based on the chain length of 3-hydroxyalkanoate repeat units, there are three types PHAs, i.e., short-chain-length (scl-PHAs, 4 to 5 carbon atoms), medium-chain-length (mcl-PHAs, 6 to 14 carbon atoms), and long-chain-length (lcl-PHAs, more than 14 carbon atoms). Previous reviews discussed the recent developments in scl-PHAs, but there are limited reviews specifically focused on the developments of mcl-PHAs. Hence, this review focused on the mcl-PHA production, using various carbon (organic/inorganic) sources and at different operation modes (continuous, batch, fed-batch, and high-cell density). This review also focused on recent developments on extraction methods of mcl-PHAs (solvent, non-solvent, enzymatic, ultrasound); physical/thermal properties (Mw, Mn, PDI, Tm, Tg, and crystallinity); applications in various fields; and their production at pilot and industrial scales in Asia, Europe, North America, and South America.journal articl
Proposal of Decision-Making Method Under Multi-Task Based on Q-Value Weighted by Task Priority
Get PDFRobots make decisions in a variety of situations requiring multitasking. Therefore, in this work, a method is studied to address multiple tasks based on reinforcement learning. Our previous method selects an action when the q-values of the action for each task correspond to a priority value in the q-table. However, the decision-making would select an ineffective action in particular situations. In this study, an action value weighted by priority is defined (termed as action priority) to indicate that the selected action is effective in accomplishing the task. Subsequently a method is proposed for selecting actions using action priorities. It is demonstrated that the proposed method can accomplish tasks faster with fewer errors.journal articl
Non-destructive Leaf Area Index estimation via guided optical imaging for large scale greenhouse environments
Get PDFThis paper presents a financially viable and non-destructive rail-based video monitoring method that utilizes optical image segmentation to estimate the canopy leaf area index (LAI) of greenhouse tomato plants. The LAI is directly related to the time-dependent crop growth and indicates plant health and potential crop yields. A rail-guided mobile camera system was commissioned that records continuous images by scanning multiple rows of two tomato plant species for over two years. UNET semantic image segmentation of the individual image frames was performed to compute the relative leaf area over time. This study also describes the image annotation process necessary to train the neural network and evaluate the segmentation results. The results are calibrated and compared to the defoliation-based (destructive) LAI estimation performed by the grower. This UNET segmentation performs well, which is enabled through the controlled environment and the well-defined boundary conditions provided by the greenhouse environment and the managed measurement conditions. Our results deviate from the manual LAI estimation by less than ten percent. Further, we are able to minimize confusion between foreground and background plants and other obstructions with an estimated error smaller than three percent, which is strictly necessary to produce reproducible results.journal articl
Probabilistic Control of Dynamic Crowds Toward Uniform Spatial-Temporal Coverage
Get PDFVehicular mobility and connectivity vary significantly over space and time when vehicular crowd sensing covers a city-wide area for a long time period, but it is important to achieve sufficiently uniform data coverage to satisfy the requirements of an environmental monitoring scenario. Our goal is thus to ensure uniform spatial-temporal coverage of sensed data over a city-wide area despite such vehicle dynamics. For a large area, trajectory-based approaches must deal with a great number and variety of participant mobility patterns. Hence, we propose a probabilistic control mechanism that adaptively adjusts the incentive to each participant, without using any prior information about participants. We provide a mathematical analysis that ensures stability of the number of participants with assigned tasks (called workers), and we evaluate the mechanism’s robustness by using 24-hr vehicle trace data from a city-wide area. Our results demonstrate that, when the number of participants is up to 1500 times higher than the required number of workers, sensing actions result in a distribution with a mean of about 1 and an interquartile range of around 4 for a required sensing interval; moreover, the mean increases by 2% when 30% of communication messages are randomly lost.journal articl
Low toxic nitromethane based monopropellant for gas generator cycle air turbo ramjet engine
Get PDFThe present study proposes ethanol-nitromethane mixture as a safe, storable, and low toxic monopropellant for a gas generator cycle air turbo ramjet engine and evaluates its propulsion performance. The present study proposes that nitromethane is mixed with ethanol to adjust gas generator combustion temperature. The author developed the computational code for the present analysis and verified its accuracy. The specific thrust of ethanol-nitromethane is nearly identical to that of ethanol-liquified oxygen and is higher than methanol-hydroxylammonium nitrate aqueous solution and hydrazine. Hydrazine has the highest Isp among the propellants in the present analysis. However, Isp of ethanol-nitromethane is nearly equal to that of ethanol-liquified oxygen and higher than those of methanol-hydroxylammonium nitrate aqueous solution, and hydroxyl terminated polybutadiene-ammonium perchlorate. With the propellant-to-air ratio range in the present study, ethanol-nitromethane has the stoichiometric condition at the ram combustor around the propellant-to-air ratio range from 0.2 to 0.25 and can obtain high ram combustion temperature. This result is favorable for ethanol-nitromethane because it improves the specific thrust and the specific impulse. Therefore, ethanol-nitromethane can be a promising low-toxic liquid monopropellant for the air turbo ramjet engine.journal articl
Geothermal electricity generator using thermoelectric module for IoT monitoring
Get PDFWe propose a power generation system for IoT monitoring, using thermoelectric generator (TEG) modules and geothermal heat sources. Moreover, optimal conditions to operate the system for a hot spring in Thailand were investigated as a case study, i.e., feasibility study for utilization of geothermal energy as renewable energy. The aggregated TEG module was installed in the heat transfer channel soaked into a hot water bath. The generated power was used to supply the Internet of things (IoT) system for hot-spring monitoring. The IoT system was connected to sensors of temperature, humidity, and sulfur dioxide (SO2) to monitor and collect the information of the hot spring. The information can be monitored on mobile phones via the application. Twenty TEG modules were installed in the heat transfer channel. The heat sinks were used to transfer the heat while soaking into the hot water bath. By using the IoT system, data of the hot-spring monitoring was collected on cloud backup. The results show that the power outputs increase relating to the increase of the temperature gradient. The correlations between the power output and the hot water bathing temperatures were reported. The IoT system can collect information of hot-spring monitoring properly. It can be suggested from these features that energy recovery from the hot spring using TEG could be a potential source of renewable energy for the IoT system.journal articl