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Effects of Particle Diameter over River Bed on Swimming Behavior of Nipponocypris Temminckii
Get PDF河川整備を行う上で魚が休憩や疲労回復が可能な領域確保が必要である．粗度下流側の低流速域に魚体が包含される巨石が魚の休憩場所になることは知られているが，魚体が完全には入り込めない小粒径を有する流れにおける魚の遊泳特性は不明である．本研究では，河床粒径を1.2～10mmの4通り，体長倍流速を2～10(1/s)の4通りに変化させて，平均体長60mmのカワムツの遊泳特性に及ぼす影響を調査した．その結果，カワムツは遊泳の合間に底面に腹部を押しつけて休憩すること，休憩中は流水抵抗を最小化させるために上流を向いて躯幹の投影面積を最小にすること，この体勢は流速および粒径の影響を受けないことが解明された．また，流速および粒径が増加しても休憩頻度は変化しないが，一回当たりの休憩時間が増加することが解明された．Fish have dark and white muscles, but they are reluctant to use their white muscles, which accumulate fatigue during swimming. Therefore, in river maintenance, it is necessary to create low velocity area where fish can move freely and to secure area where they can rest. In this study, investigation of the effect of the riverbed grain size on the fish swimming behavior was conducted. The effects of four different grain sizes (1.2 to 10 mm) and four different velocity normalized by the body length (2 to 10 (1/s)) were investigated using Nipponocypris temminckii with 60mm body length. As a result, it was found that fish rested by pressing their abdomens against the bottom in between swimming, and fish turned upstream direction to minimize the projected area of the body to minimize the water resistance. It was also found that the frequency of resting did not change with velocity and grain size, but the resting time per rest increases.journal articl
Clarifying the Dominant Role of Crystallinity and Molecular Orientation in Differently Processed Thin Films of Regioregular Poly(3-hexylthiophene)
Get PDFConjugated polymers (CPs) offer the potential for sustainable semiconductor devices due to their low cost and inherent molecular self-assembly. Enhanced crystallinity and molecular orientation in thin films of solution-processable CPs have significantly improved organic electronic device performance. In this work, three methods, namely spin coating, dip coating, and unidirectional floating-film transfer method (UFTM), were utilized with their parametric optimization for fabricating RR-P3HT films. These films were then utilized for their characterization via optical and microstructural analysis to elucidate dominant roles of molecular orientation and crystallinity in controlling charge transport in organic field-effect transistors (OFETs). OFETs fabricated by RR-P3HT thin films using spin coating and dip coating displayed field-effect mobility (μ) of 8.0 × 10−4 cm2V−1s−1 and 1.3 × 10−3 cm2V−1s−1, respectively. This two-time enhancement in µ for dip-coated films was attributed to its enhanced crystallinity. Interestingly, UFTM film-based OFETs demonstrated μ of 7.0 × 10−2 cm2V−1s−1, >100 times increment as compared to its spin-coated counterpart. This superior device performance is attributed to the synergistic influence of higher crystallinity and molecular orientation. Since the crystallinity of dip-coated and UFTM-thin films are similar, ~50 times improved µ of UFTM thin films, this suggests a dominant role of molecular orientation as compared to crystallinity in controlling the charge transport.journal articl
Centrifuge Experiment on Capture Performance of Open-Type Sabo Dam with Its Numerical Analysis
Get PDFOpen-type Sabo dam captures the advantage of solids mitigating the potential energy of fluids, but the disadvantage is that a small amount of debris flow passes through the dam, the reason for this comes from the grid size of the dam, the inclination angle of the dam, the stone size among the debris flow, etc. This study aims to investigate the influence of the inclination angle on the capture performance of the open-type Sabo dam. A model experiment is conducted based on the centrifuge machine. Three open-type Sabo dam models reflecting different inclination angles of 0° (vertical form), 20°, and 40° are used to capture the debris flow. The concentration of the large particle (CLP) for the debris flow configuration is set to 20% and 33%, respectively. The experimental results indicate that the open-type Sabo dam with 0° inclination angle has the best capture rate, 93%–94%. An increase in inclination decreases the capture rate for debris flows. A 40° inclination angle decreases the capture rate by 2%–8%, and this decrease is exacerbated by an increase in CLP of the debris flow. Additionally, the smoothed-particle hydrodynamics–distributed contact distinct element method (SPH–DCDEM) has a good reproduction for the experimental result of the capture rate, with an error of 12%–25%.journal articl
Hetero atom-based metal complexes as emitters in organic light-emitting diodes
No full textThe new, more energy-efficient lighting systems and high-quality displays for new age digital devices is the demand of the current generation. In this regard, focused and deliberated research has been done on transition metal complexes as effective building blocks for organic light-emitting diodes (OLEDs). The activity of divalent metallic compounds was investigated through spotlighting Co (II), Ni (II), and Cu (II) metal ions with guanidinium naphthoate as blue phosphors in OLEDs. Using spectroscopic and diffraction techniques, the phosphors produced at the optimal temperature were studied both structurally and thermally. Additionally, the target compound's photophysical investigations in a variety of organic solvents with differing polarities were examined, and the findings were presented. Because of their quick photoluminescence response time and high emission quantum efficiency, Ni (II) complexes have drawn specific attention. Ni (II) complexes precisely exhibit thermally activated delayed fluorescence (TADF) and found to be the most promising materials for future lighting technology. We compared the efficiencies of various complexes in this study to provide an overview of the development of OLEDs. To affirm the pertinency of the synthesized compounds as phosphors, studies like photoluminescence, correlated color temperature, color purity, Duv, and the Television Lighting Consistency Index (TLCI) were performed and their photometric properties were also deliberated. Ni (II) shows an magnificent luminescence character and maximum coloring index for light sources and found to be an essential component for OLEDs.journal articl
Advancing dye-sensitized solar cell performance with bifacial illumination: A novel Stack Formation Framework approach
No full textDye-sensitized solar cells (DSSCs) are considered to be one of the promising photovoltaic devices in terms of low cost, low toxicity, and versatility. However, the issue of low power conversion efficiency (PCE) is still a main issue of those devices, especially in low light harvesting and the issue of electron–hole recombination that hinders the PCE of the device. This study aims to enhance the PCE by maximizing the light-harvesting without sacrificing the electron–hole separation by a novel approach of the Stack Formation Framework (SFF) for multi-layered Titanium Dioxide (TiO2) photoanodes in DSSCs by integrating bifacial illumination capabilities. The SFF method, leveraging both commercial and synthesized TiO2 pastes, now considers light absorption from both the front and rear sides of the device, aiming to harness the full potential of ambient light sources. Comparative analyses under varying illumination conditions reveal the T/sp-P25-T/sp (TPT) configuration’s superior efficiency (6.1%) and (3.8%) PCE in front and back respectively, with a notable increase in overall theoretical photocurrent (Jsc) to (15.99 mA) and (9.32 mA) in front and back illumination respectively. When both sides are utilized using a reflective mirror, the PCE reaches (9.9%). This work underscores the potential of bifacial DSSCs in maximizing energy capture and conversion, setting a new benchmark for photoanode performance in photovoltaic applications.journal articl
CMOS digital-analog mixed signal VLSI implementation of a hippocampus-inspired model
Get PDFFor artificial intelligence (AI) to be useful in the home, it is required to acquire unique knowledge of the home obtained through interaction with space and environment. This is difficult for deep learning-based AI. The human brain can learn unique knowledge from few experiences. The entorhinal cortex and hippocampus play essential roles for episodic memory formation and recall. While entorhinal-hippocampal models have been proposed that can reproduce episodic memory, hardware systems that implement such models face challenges related to high computational complexity, power consumption, and processing speed. In this paper, we propose a digital-analog mixed-signal CMOS VLSI implementation of a hippocampus-inspired model that can memorize and associate place and object information essential for the formation of episodic memory. By using both analog and digital in-memory computing architecture, the proposed circuit has achieved a computational efficiency of 22 TOPS/W, which is very high for AI hardware with a learning function. The proposed circuit was fabricated, measured, and evaluated. The results of an experiment using a fabricated chip and a control system showed that the proposed circuit can memorize and process place and object information, and can acquire environment-unique knowledge through interaction with a space.journal articl
A novel soil stress estimation method of wheel-soil interaction using photoelasticity
Get PDFThis paper proposes a new approach to understanding the wheel-soil interaction, which is an indirect estimation method of soil stress distributions beneath a traveling wheel soil using a photoelastic method. Thus far, in the conventional studies applying the photoelastic method to the wheel-soil terramechanics, the terrain has been emulated by photoelastic disks or plates, which enable visualization of internal stresses in the simulated terrain. In particular, the photoelastic disks have performed visualization of two-dimensional dynamic stress distributions of the simulated granular terrain. With this method, we have visualized and analyzed the dynamic force chain structure of the terrain under different wheel slip conditions. Still, it is difficult for the previous configuration to simulate the dynamic behaviors of natural soil, e.g., compaction, failure, or wheel ruts. Accordingly, achieving both the stress visualization and the dynamic behaviors of soil is a significant challenge to make the photoelastic method more practical. To cope with this challenging issue, we have developed a novel experimental setup consisting of a photoelastic wheel (top layer), soil (middle layer), and a photoelastic plate (bottom layer). By vertically sandwiching the soil between the photoelastic wheel and plate, the soil stresses can be indirectly estimated to satisfy the boundary stress conditions. To achieve this approach, we have conducted calibration tests of the photoelastic wheel and plate, and then identified the force vector and contact patch corresponding to the visualized stresses. In this paper, we demonstrate that it is possible to indirectly estimate how the stress propagates and attenuates in the soil by the proposed method.conference pape
An Innovative Method of Teaching Grammar and its Impact on Standardized Test Scores
Get PDFEnglish grammar instruction in Japan has remained relatively unchanged for decades, with one issue being a pedagogical divide in English instruction that designates some grammatical forms as simple while others as more complicated and challenging. Another problem is that some forms in grammar are frequently taught, while other forms are rarely addressed; furthermore, attention to actual usage in various contexts is often disregarded. This research investigated whether a listening or a grammatical module would have the most impact on raising Test of English for International Communication (TOEIC) scores. Over five hundred freshman Japanese college students took part in the investigation. The participants consisted of two groups, one doing a Moodle-based e-learning program and the other completing a conventional TOEIC-based Listening Lab. For the first grammatical module, an e-learning program for English grammar utilizing the concepts of strands and clusters was developed. A strand involves any grammatical form that is recycled in various contexts over several weeks. Grammar is then presented in clusters (clauses/phrases) and how each form might impact the other in various kinds of discourse. The research concentrated on distinctions between the two groups, dissimilarities in quizzes, classes, and progress during the two semesters. The findings indicated a difference between the two, with the Listening Lab achieving an approximately 38-point rise and the grammar e-learning program a 43 rise. The test score revealed a linear increase in the standard deviation, with learners improving their points by 0.17 scores per quiz. The standardized scores rose through e-learning, with mixed results.journal articl
需要予測のためのモンゴルの電力消費量の変化と特徴および温度依存性に関する研究
Get PDF九州工業大学博士（工学）1 INTRODUCTION| 2 DATA ACQUISITION OF EP CONSUMPTION AND TEMPERATURE IN MONGOLIA AND JAPAN| 3 FEATURES OF ELECTRIC POWER CONSUMPTION IN MONGOLIA AND COMPARISON WITH JAPANESE PROPERTIES| 4TEMPERATURE DEPENDENCE OF ELECTRIC POWER CONSUMPTION IN MONGOLIA AND ELECTRICITY USAGE FOR COOLING AND HEATING AIR-CONDITIONING| 5 CONCLUSIONSThis dissertation consists of five chapters, and the outline of each chapter is as follows:
Chapter 1 introduced the overview of EP systems in Mongolia and the government plan, the methodology, and the objectives of this dissertation.
Chapter 2 described how to obtain data on electric power (EP) consumption in Mongolia and Japan. Mongolian EP data was provided by the NPTG from January 2017 to March 2021, and it was the maximum and minimum values of an hour in a day. The daily EP consumption was estimated based on the hourly maximum and minimum values. In this method, the daily EP consumption of the Japanese EP companies was estimated and compared with the total hourly EP demand in a day. The regression analysis and relative errors were applied to evaluate the daily EP consumption. The temperature data was obtained from meteorological agencies in major cities in EP company's business areas in Mongolia and Japan.
In Chapter 3, Mongolian EP consumption features were quantitatively clarified in respective timeframes – yearly, monthly, weekdays and special days and compared with 10 Japan EP companies. The study reveals that Mongolian EP consumption demonstrates an average annual growth rate of 5% from 2017 to 2020. Seasonally, Mongolian EP consumption increases from summer to winter, with a small EP consumption difference of 1.5% between weekdays and weekends. Conversely, Japanese EP consumptions maintain a consistent annual trend, marked by two peaks during the summer and winter seasons. Furthermore, the differences in EP consumption between workdays and weekends in Japanese EP companies are notably higher, ranging from 3 to 12 times greater than that observed in Mongolia.
In Chapter 4, the relationship between daily EP consumption per capita and daily average temperature was investigated, encompassing Mongolia and 10 Japanese EP companies. The study revealed differing patterns: Mongolia has a linear relationship, whereas Japan has a U-shaped relationship between these variables. Notably, Mongolia's per capita EP consumption was found to be 1/4 lower than that of Japan. The study applied the degree day method (DDM) model to separate EP consumption into heating degree day (HDD) and cooling degree day (CDD) by the base temperature. It was found that the temperature sensitivity of CDD has one straight line with the seasonal temperature, while the sensitivity of HDD has multiple lines. The findings suggest that knowing the seasonal temperature of the target area allows us to estimate heating and cooling energy.
Chapter 5 is a summary of the thesis and future research and challenges.九州工業大学博士学位論文 学位記番号:工博甲第595号 学位授与年月日:令和6年9月25日令和6年度doctoral thesi
Automatic judgement, storage of 3D models, and reproduction using 3D printers of weld bead shapes at welding competitions
Get PDF溶接技術競技会では，板材の突合せ溶接を行う競技課題が多く，採点には外観判定や放射線透過試験，曲げ試験などが適用される．外観判定は判定基準にもとづき熟練の評価員が手動で行う必要がある1）．また，曲げ試験を行う場合は作製した作品を保存できなくなる．そこで，作品の溶接ビード形状をレーザ変位計で計測して，計測データをプログラム処理することで外観判定を自動で行うとともに，計測データを3Dデータに変換・保存し，さらに溶接ビード形状を3Dプリンタで再現した．その結果，採点基準に従って溶接ビード形状の自動判定を行うことができた．また，実物に近いイメージが確認できる溶接ビード形状の3Dモデルとレプリカを作製することができた．In welding competitions, many of the competition tasks involve butt welding of plates, and the scoring involves appearance judgment, radiographic examination, bending test, etc. Appearance judgment must be performed manually by an experienced evaluator based on judgment criteria. Also, if a bending test is performed, the created work cannot be saved. Therefore, we measured the weld bead shape of the work with a laser displacement meter, automatically judged the appearance by processing the measurement data with a program, converted and saved the measurement data to 3D data, and then reproduced the weld bead shape with a 3D printer. As a result, it was possible to automatically judge the weld bead shape according to the scoring criteria. In addition, it was possible to create a 3D model and replica of the weld bead shape that was close to the real thing.journal articl