This report describes the development of teaching materials for problem-solving practical training on electrical wiring practice in electrical engineering, which was implemented over a three-year period. The proposed teaching materials formulated and used a “Problem Setting Sheet” as a resource for the achievement status and evaluation of assignments. This allowed students to work as a team in setting and implementing issues and goals and managing the process to achieve them. The results showed that the developed PBL practices increased the problem-solving ability of the teams, as well as the students’ motivation to study specialized subjects and their awareness of career design.

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近年我が国では少子高齢化が問題となっている。少子化に伴い働き手となる介護福祉士が不足している。一方で高齢化による介護を必要としている人の増加も問題となっており，その増加につれ認知症患者になる人も増えている。認知症患者の中には夜間徘徊を行う人もおり，死亡事故に至るケースもあり問題となっている。 本研究では，その夜間徘徊を防止するために超音波センサを用いた行動検知器の研究開発を行っている。すでに開放型超音波センサを用いた行動検知器は完成しており技術提供もしている。数年前より，様々な状況にも対応できるために、防滴型センサを用いた検知装置の研究開発を行っている。Fig. 1に防滴型超音波センサを示した。しかし，防滴型超音波センサは，開放型超音波センサと同じ性能にするためには印加電圧をDC9ＶからDC50Ｖまで昇圧する必要があり，介護の現場においてこの数字は危険であるため，DC15Ｖまで降圧が必要であった。昨年度の研究によってDC25Ｖまで降圧されたが，測定可能距離が150cmとまだまだ足りない上，危険な電圧である。 今年度の研究では更なる降圧，測定距離の向上，受信精度の向上を目標とした。

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NIT, Ube College has been selected for the Global Engineer Project and has been implementing global education, especially for the lower grades of the first through third year, since the 2019 academic year. However, NIT, Ube College has already been conducting mutual exchanges of faculty members and students through academic exchange agreements with overseas educational institutions for more than a decade. In 2018, before the coronavirus pandemic broke out, there were 105 students who received language training and specialized experiments and practical training at overseas partner schools during summer and spring long vacations, and 59 short-term international students from those schools. However, there are a significant number of students who are not active in activities conducted both on and off campus, and the challenge is how to involve such students. What we have tried to do is to globalize the campus, and I would like to introduce three initiatives that we have implemented during the past two years of pandemic. The first was to provide online language training and overseas training, and position it as an official course for which credit can be granted. In addition, online English conversation classes were made available to students who wished to take them. The second is the “Global Engineer Lecture Series,” in which alumni with overseas work experience give lectures online. In FY2021, five lectures were held. The third is the implementation of after-school English conversation classes utilizing foreign faculty members and long-term international student tutors, in which many students in lower grades participate, leading to an increase in the level of globalization on campus.

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An experimental study is carried out for natural-convection heat transfer to air from upward-facing and downward-facing heated circular plates under the condition that the amount of heat dissipating through the side wall of the plates is sufficiently negligible.
For the case of upward-facing plate, it is shown that in laminar flow region, the temperature distributions in air near the plate are similar when the Rayleigh numbers of the experimental runs are equal to each other. A correlation equation is proposed for the average heat transfer coefficient, with the discussion on the applicability of previously proposed equations.
Another heat transfer correlation is proposed for downward-facing plate and compared with previousily proposed experimental and theoretical correlations. Moreover, a profile method is applied to investigate the functional forms of the velocity and temperature profiles in boundary layer.

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  Nanocrystalline Ni-W alloy specimens containing 16.9 at% W with about 20 μm in thickness, 50 μm in width and 4 mm in parallel part length were produced by using both UV photolithography and electrodeposition methods. The average grain size was about 6 nm in diameter. The tensile test was conducted at a strain rate of 1.4×10⁻⁴ s⁻¹. The nominal tensile strength and Young's modulus were about 2.8 GPa and about 125 GPa with or without polishing, respectively. The elastic strain and plastic strain on the polished specimen were about 1.9% and 0.76%, respectively and those on the non-polished specimen were about 1.9% and 0.49%, respectively. The true tensile strength on the polished and non-polished specimens were 3.8 GPa and 3.4 GPa, respectively. In addition, the stress-strain curve showed work hardening. The macroscopic fracture part yielded necking and the microscopic fracture surface showed dimple pattern.

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  Fracture toughness of the Cu-Zr-Ti bulk metallic glass (Former Cu-Zr BMG) under plane-strain condition could not be evaluated because the BMG with a sufficient thickness for the plane strain condition had not been fabricated. However, as the fracture morphology was similar to that in the Zr-based BMGs having the large plane-strain fracture toughness (K_IC), e.g. about 50 MPa•m^1/2, it was presumed that the Former Cu-Zr BMG has a large K_IC. Recently, in Cu-Zr-Ag-Al BMG (New Cu-Zr BMG), a large sample of 25 mm in diameter became possible to be made. Therefore, in this study, K_IC of the New Cu-Zr BMG was investigated. The New Cu-Zr BMG plate sample of Cu₃₆Zr₄₈Ag₈Al₈ was made by a copper mold casting method. Tensile strength was 1850 MPa and Young's modulus was 115 GPa. Compact type specimen with 2.3 mm in thickness and 9.2 mm in width was used. Fatigue pre-crack was induced under stress intensity factor range (ΔK) less than 6 MPa•m^1/2, and the fracture toughness test was conducted at a loading rate of 1 MPa•m^1/2•s^-1. The new Cu-Zr BMG exhibited a K_IC of 17 MPa•m^1/2. The former Cu-Zr BMG that could not satisfy the plane-strain condition exhibited a fracture toughness of 62 MPa•m^1/2. The stretched zone width along the inner fatigue crack front and vein pattern size on the unstable fracture surface in the new Cu-Zr BMG were smaller than those of the former Cu-Zr BMG. Therefore, it seems that the K_IC of the new Cu-Zr BMG is smaller than that of the former Cu-Zr BMG.

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  Fracture toughness tests were carried out using different Zr composition in Zr-Cu-Al based bulk metallic glasses (BMGs) and heat-treated those just under the glass transition temperature (T_g) in order to examine the effects of Zr composition and heat-treatment on the fracture toughness (K_Q; fracture toughness including the values under unsatisfying the plane strain condition). Zr₅₀Cu₄₀Al₁₀, Zr₅₅Cu₃₅Al₁₀ and Zr₆₀Cu₃₀Al₁₀ BMGs fabricated by a tilt ark casting method were used. Heat-treatments were done for 90 minutes just under the T_gs of each BMG. Tests were conducted based on ASTM E399. Compact type specimen was used (thickness=2.3, 2.0 mm, thickness : width=1 : 4). Fatigue pre-crack was induced under ΔK less than 6 MPa•m^1/2 by a servohydraulic fatigue machine and the fracture toughness test was done by using the same machine. The K_Q dominantly increased with increasing the Zr composition. The K_Q in heat-treated BMGs decreased in comparison with that in unheat-treated BMGs in all Zr composition. In the BMG of the high Zr composition, however, the decrease was small after heat-treatment, and the K_Q showed enough high values. In heat-treated BMGs, the dispersion of K_Qs did not become small, but fatigue pre-cracks were induced more vertical against the loading axis and less bifurcation than those in unheat-treated BMGs.

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Banda Aceh is the capital and largest city in the province of Aceh, the island of Sumatra, Indonesia, which is located on the northwestern tip of Indonesia at the mouth of the Aceh River. The city rose to international prominence in the Indian Ocean earthquake in 2004, which struck off the western coast of Sumatra. It suffered great damage in the earthquake and further damage when a tsunami struck shortly afterwards. An inspection of the old and new waste dumping sites was carried out in Banda Aceh. This report describes an improved design concept of waste dumping site in Banda Aceh after the big earthquake.

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  Bulk metallic glasses (BMGs) have many unique mechanical properties, e.g. extremely high strength and bending ductility. However, very limited data are reported on tensile ductility on BMGs. Recently there has been interest in strain rate dependence of fracture behavior in BMGs, such as fracture strength, plastic deformation and shear band formation. Meanwhile, we indicated that a hypoeutectic Zr-Cu-Al BMG shows longer and many shear bands and higher fracture toughness than a eutectic Zr-Cu-Al BMG. In this study, tensile test on a hypoeutectic Zr-Cu-Al BMG is performed under several different strain rates. Effect of strain rate on the mechanical properties such as tensile strength and Young's modulus are investigated. Also, it is ascertained whether the tensile plastic elongation in the hypoeutectic Zr-Cu-Al BMG occur or not. The hypoeutectic Zr-Cu-Al BMG is fabricated by an arc-tilt casting method. Chemical composition is Zr₆₀Cu₃₀Al₁₀ at%. Tensile test is carried out under several strain rates. As a result, it was found that Young's modulus, tensile strength and elastic strain are about 90 GPa, 1700 MPa and 2%, respectively. Also the tensile specimen fractured with the shear plane inclined 52-55 degree for the loading axis. All these values were independent on the strain rate. Under any strain rate, the tensile plastic elongation did not occur and the multiple shear bands were not observed in the specimen surface.

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  Relationship between fracture toughness and shear band length (SBL), crack tip opening displacement (CTOD) on the specimen surface and stretched zone width (SZW) on the fracture surface in Zr-, Cu- and Ti-based bulk metallic glasses (BMGs) was investigated in order to examine the mechanisms that the BMGs show a high fracture toughness. Zr₅₀Cu₄₀Al₁₀ and Zr₅₀Cu₃₀Ni₁₀Al₁₀ BMGs fabricated by an ark tilt casting method, and Cu₆₀Zr₃₀Ti₁₀, Ti_41.5Zr_2.5Hf₅Cu_42.5Ni_7.5Si₁ BMGs fabricated by a high-frequency induction casting method were used. The fracture toughness test was conducted based on ASTM E399. Compact type specimen was used (1.0 mm, 2.0 mm and 2.3 mm in thickness, thickness:width=1:4). Fatigue pre-crack was induced under ΔK less than 6 MPa•m^1/2. The crack length and SZW were measured on the fractographs by scanning electron microscope (SEM), and the SBL and CTOD were measured on the photographs of specimen surfaces by the SEM. Observed SBL and CTOD in each BMG showed the near values of the plastic zone size and CTOD calculated by the fracture mechanics under the plane stress condition, respectively. By the stereo-matching observation on the fracture surfaces, the crack tip inside the specimen clearly opened and a stretched zone area was shown. Average SZW in front of the fatigue crack in the Zr- and Cu-based BMGs was roughly proportional to the fracture toughness value.

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  Tensile test and V-notch Charpy impact test were performed on a series of ferritized spheroidal graphite cast irons containing 1.9～3.6%C-1.6%Si, 1.9%C-1.5～4.2%Si, 3.6%C-2.1%Si and 3.3%C-3.7%Si. The ferritization treatment was made on as cast specimens with 0 to 100% pearlite by heating them at 900℃ (1173K) for 2h, cooling to 600℃ (873K) in a furnace at (900℃ (1173K)-600℃ (873K)) /24h and air cooling. The 0.2% proof stress and tensile strength of ferritized iron increase linearly with decreasing C content. The elongation becomes higher at lower C content. Charpy absorbed energy in the upper shelf also increases with decreasing C content. These effects of decreasing carbon are thought to be mainly caused by the increase in the fraction of matrix. However, the transition temperature of absorbed energy becomes higher with the decrease in C content. Graphite nodules remarkably reduce the upper shelf energy, while they significantly lower the transition temperature. Higher Si content effectively increases both 0.2% proof stress and tensile strength due to strong solution hardening ability of Si. Although the elongation decreases linearly with the increase in Si content, it shows still 20% at 4.18%Si. On the other hand, both the upper shelf energy decreases and the transition temperature becomes higher with the increase in Si content. A proper combination of C and Si content is key to the higher performance of ferrite matrix spheroidal graphite cast iron.

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An experimental study on enhancement of nucleate pool boiling heat tranfer by placing a sponge metal close to a plain heated surface was conducted in order to improve the heat transfer performance of the high temperature generator of absorption chiller/heater. The sponge metal has three dimensional porous mesh framework like sponge.
Boiling curves of water under the atmospheric pressure were compared with those of lithium bromide aqueous solution of mass concentration 55 to 58%. Heat transfer characteristics were improved by 2 to3 times both for water and lithium bromide aqueous solution when the sponge metal was placed on the heated surface with and without cleareance.
Three kinds of sponge metals were used for lithium bromide aqueous solution under the reduced pressure (24 kPa). At lower heat fluxes,#6 sponge metal which has the finest mesh and the lowest porosity shows excellent results. At high heat fluxes, however,it causes deterioration of heat transfer. Over the wide range of heat fluxes,# 4 sponge metal was found to be most suitable and the optimal clearence was determined as 0.5 mm.
The sponge metal is of good practical use as a device to enhance the boiling, since no special manufacturing is required for placing it on the heated surface.

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