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桁端部に腐食損傷を生じた鋼橋の支点部の耐荷性能に関する解析的研究
Get PDF北見工業大学博士（工学）１．１．１ 道路橋の老朽化
我が国の経済活動を支える基盤である社会資本は，高度経済成長期以降に多く整備され，
道路橋についても同様である．図－1.1.1 に国内の橋長 15m 以上の道路橋の建設年代を示す
1)．本図より，高度経済成長期が始まったとされる昭和30（1955）年より後に建設された橋
長 15m 以上の道路橋は約21 万橋あり，全体の約94%を占める．道路橋の建設のピークは
昭和48（1973）年頃であり，5000 橋近くの道路橋が1 年間で建設された．このため，令和
5（2023）年には，これらの道路橋が建設後50 年を迎える．また，建設後50 年を超える橋
梁数は，令和4（2022）年の段階で約6 万橋（全体の約28%），20 年後の令和24（2042）年
には約16 万橋（全体の約71%）となる．道路橋の寿命は一概ではないが，一般的に50 年程
度とされることが多く，建設後50 年を超える橋梁を老朽化橋と定義すると，20 年後には約
7 割の道路橋が老朽化橋になるといえる2)～4)．更に，中小橋を含めると，全国に架設される
橋長 2m 以上の道路橋は，道路統計年報5)によると約69 万橋が架設されている．橋長 2m
以上の道路橋でも橋長15m 以上の道路橋と同様の建設年代の傾向があるとすると，20 年後
には全国で約48 万橋が老朽化橋となる．また，老朽化により実際に通行止めや重量制限等
の通行規制を実施する道路橋も年々増加しており，令和元（2019）年の調査では全国で交通
不能の橋長 2m 以上の道路橋は約5500 橋，通行制限を設ける道路橋も約3600 橋あるとさ
れ，老朽化による損傷が顕在化していると推測できる6)．doctoral thesi
Shallow firn cores 1989–2019 in southwest Greenland's percolation zone reveal decreasing density and ice layer thickness after 2012
Get PDFRefreezing of meltwater in firn is a major component of Greenland ice-sheet's mass budget, but in situ observations are rare. Here, we compare the firn density and total ice layer thickness in the upper 15 m of 19 new and 27 previously published firn cores drilled at 15 locations in southwest Greenland (1850–2360 m a.s.l.) between 1989 and 2019. At all sites, ice layer thickness covaries with density over time and space. At the two sites with the earliest observations (1989 and 1998), bulk density increased by 15–18%, in the top 15 m over 28 and 21 years, respectively. However, following the extreme melt in 2012, elevation-detrended density using 30 cores from all sites decreased by 15 kg m−3 a−1 in the top 3.75 m between 2013 and 2019. In contrast, the lowest elevation site's density shows no trend. Thus, temporary build-up in firn pore space and meltwater infiltration capacity is possible despite the long-term increase in Greenland ice-sheet melting.journal articl
Local slip activities in polycrystalline α-Ti depending on textures and strain rates
Get PDFIt is possible that strain localization in polycrystalline α-Ti leads to the fracture, and it is crucial to evaluate the local slip activities for individual slip systems depending on their textures and loading conditions. In this study, the effects of textures and strain rates on local slip activities were investigated using the crystal plasticity finite element method. For the analysis, microstructural models of α-Ti with the following three textures were employed: aggregates of (0001) axes are (i) splitting in rolling direction (RD-split texture), (ii) splitting in transverse direction (TD-split texture), and (iii) aligned in normal direction (basal texture). For each texture model, two variations in the crystal orientation distributions were considered, namely, small and large scatterings of crystal orientations in the (0001) axes by normal random numbers. The differences in the strain rate sensitivities of the critical resolved shear stresses (CRSSs) among slip systems were also considered. Tensile loading was applied by a forced displacement in the RD with two strain rate conditions of 1.0 × 10−4 s−1 and 1.0 × 10−1 s−1. Local non-prismatic slips were easier to operate in the models with basal and RD-split textures than with the TD-split texture. The slip strains for non-prismatic slip systems were higher at higher strain rates, while activities in the prismatic slips decreased with an increase in strain rates. The mechanism of the exchange of slip system activities can be explained by strain redistribution between hard and soft regions and changes in CRSS as a function of strain rates.journal articl
Effects of temperature and crystallographic structure on helium concentration in the mixed-gas hydrate containing helium
Get PDFヘリウムは天然ガスの成分の一つであり，天然ガスハイドレートの分解ガスからヘリウムが検出されたとの報告があるものの，ヘリウムが結晶中に包接されているかどうかは不明である．本研究では，メタン（構造 I 型）およびアルゴン（構造 II 型）にヘリウムを混ぜた混合ガスを用いてハイドレート結晶を生成し，結晶中に含まれるヘリウム濃度を調べた．一定温度で脱気し続けると，結晶中のヘリウム濃度は時間とともに減少すること，高温ではヘリウム濃度の低下が速いこと，構造 I 型より II 型のほうが相対的に低くなること，がわかった．journal articl
A Walk Around Kitami
Get PDF文：鈴木 衛
訳：ボゼック クリストファー ジョン
絵：鈴木 彩夏北見中心部 Central Kitami… …………………………………………………………………2
北見駅 JR Kitami Station………………………………………………………………………4
北見バスターミナル Kitami Bus Terminal……………………………………………………5
パラボ Parabo… ………………………………………………………………………………6
北見市役所 Kitami City Hall……………………………………………………………………7
北見市立中央図書館 Kitami City Public Central Library……………………………………8
北見芸術文化ホール（きた・アート21） Kitami Art and Culture Hall (Kita∙Art21)…………8
オホーツク木のプラザ Okhotsk Wood Plaza…………………………………………………8
野付牛公園 Notsukeushi Park……………………………………………………………… 10
ピアソン記念館 Pierson Memorial House… …………………………………………… 12
北見ハッカ記念館 Kitami Mint Memorial Museum……………………………………… 14
北見工業大学 Kitami Institute of Technology…………………………………………… 16
日本赤十字北海道看護大学 Japanese Red Cross Hokkaido College of Nursing… … 17
北見市中心街 Downtown Kitami… ……………………………………………………… 18
おんねゆ温泉 Onneyu Hot Spring………………………………………………………… 20
山の水族館 YAMA NO Aquarium… ……………………………………………………… 21
からくりハト時計塔「果夢林」 Kamurin Cuckoo Clock Tower… ……………………… 21
ワッカ原生花園 Wakka Wildflower Park………………………………………………… 22
ところ遺跡の森 Tokoro Forest of Remains… …………………………………………… 22
オジロワシ White-Tailed Eagle… ………………………………………………………… 23
サロマ湖ホタテ漁 Lake Saroma Scallop Fishing………………………………………… 23
北見ぼんちまつり舞踊パレード Kitami Bonchi Festival Dance Parade… …………… 24
北見厳寒焼き肉まつり Kitami Mid-Winter Barbecue Festival… ……………………… 25
玉ねぎの収穫 Onion Harvest… …………………………………………………………… 26
きたみファミリーランド Kitami Family Land……………………………………………… 28
北見市民スケートリンク Kitami Municipal Skating Rink………………………………… 30
スキー Skiing………………………………………………………………………………… 31
カーリング Curling…………………………………………………………………………… 32
北見の夜空とアイスキャンドル Evening Sky and Ice Candles in Kitami… …………… 34boo
背水の影響区間における 河床波の発達過程に関する水理実験
Get PDF下流端水位が異なる場における小規模河床波の発達状況とその影響で生じる水位縦断形状の把握を目的
に，水理実験を実施した．ならびに，ブルーレーザを用いて非接触で水面形と水面下の河床計測を試み，
移動床実験におけるその有用性も議論した．実験の結果，せき上げのケースでは水路全区間で河床波が発
達し維持され，それに伴い水位が上昇した．一方，低下背水のケースではある区間において急速な河床波
の発達が見られたことから，流れが加速する状況下において河床波の発達が促進される条件が存在する可
能性が示されたjournal articl
機能性薄膜と電気化学デバイスの作製と評価 及び機械学習の応用
Get PDF北見工業大学博士（工学）In this study, WO3 NPs dispersion ink with excellent adhesion was developed for the
fabrication of electrochromic devices capable of wet coating, device fabrication tests were
performed using the developed materials, and performance was predicted and
demonstrated using machine learning.
To improve the adhesion between the WO3 nanoparticles and the substrate of the ink,
polyvinyl alcohol (PVA) was added as an additive. PVA was adjusted to 0-10 wt.%, and
electrochemical properties and EC properties were studied. As a result, the WO3 thin film
prepared with 1 wt.% PVA addition showed excellent adhesion between WO3
nanoparticles and substrate. In addition, it was found that the composition of the WO3
thin film exhibiting excellent electrochemical properties with the largest coloration
efficiency of 35 cm2/C and electrochromic properties with a change in visible light (λ =
633 nm) transmittance of 90%⇔13%.
To fabricate the next-generation EC device, we investigated the fabrication of flexible
ECD using a PET substrate. For the preparation of EC materials, coated WO3 and PB
films were prepared using the WO3 synthesized in Chapter 3 and the PB ink originally
developed by Adhesion and Interface Research Group at National Institute of Advanced
Industrial Science and Technology (AIST), and these were assembled to prepare a flexible
EC device. The prepared flexible PET EC device showed a dramatic color change from
transparent to dark blue and showed higher coloring efficiency (123.32 cm2 / C) than the
conventional glass EC device (86.44 cm2 / C). Furthermore, it showed electrochemical
stability without deterioration up to 100 cycles, and mechanically excellent durability
against repeated bending and twisting experiments.
Finally, machine learning was applied to obtain the optimal WO3 NPs dispersed ink
preparation condition for the application of EC materials. The predicted value obtained
through simulation showed an accuracy of more than 90% with the experimental value.
In addition, the highest coloring efficiency value of 38.2 cm2/C obtained through this
study was improved by about 10% compared to the coloring efficiency value (35.0 cm2/C)
of Chapter 3. Therefore, we believe that it is possible to develop an optimized process for
the preparation of EC materials using machine learning. In the future, we will focus on
the development of functional nano-dispersion inks optimized to prepare functional thin
films using various parameters (materials, manufacturing conditions, atmosphere, etc.)
through simulation prediction using more advanced algorithms.doctoral thesi
Numerical prediction of {11-22}<11-2-3> compression twin activation in commercially pure titanium under uniaxial tension
Get PDFIn this study, the criteria for
compression twinning in commercially pure titanium (CP–Ti) were investigated by uniaxial tensile tests, crystal plasticity finite element (CPFE) analyses, and slip operation factor (SOF) calculations. First, the aggregates of the [0001] axes of CP-Ti were inclined in the rolling direction (RD), implying its RD-split texture. The development of the crystal orientation distribution with deformation was observed by electron back-scattered diffraction (EBSD). Active slip systems were identified by kernel average misorientation (KAM) and intergranular misorientation axis (IGMA) analyses. The dominant slip system was prismatic , whereas the non-prismatic slip systems were activated near the grain boundary. Active twin systems were also identified by the rotation angles of the [0001] axes between the twin and matrix. The dominant active twin system was the
compression twin, although a uniaxial tensile load was applied. Second, the positions of
twinning were predicted by CPFE analysis using the resolved shear stress (RSS) criterion while considering plastic deformation. SOF analysis was also employed for the prediction. The CPFE and SOF analyses yielded almost the same level of prediction accuracy. However, these calculations do not completely predict the twinning positions. Finally, the criteria for
twinning were discussed, and it was revealed that hydrostatic pressure and RSS are possible criteria for
twinning in the continuum model.journal articl
Color modulation of electrochromic nanosheet-structured nickel-cobalt oxide thin films
Get PDFNickel–cobalt (Ni–Co) oxide thin films were directly grown on the fluorine-doped tin oxide (FTO)-coated glass substrates via a simple one-pot solution process using various ratios of Ni and Co precursors. All the Ni–Co oxide samples were composed of nanosheet structures that were vertically aligned on the surface of the substrates. The nanosheets of the Ni10–Co0, Ni8–Co2, Ni6–Co4, and Ni4–Co6 oxide samples uniformly covered the surface, whereas those of the Ni2–Co8 and Ni0–Co10 oxide samples were sparsely distributed. As the ratio of Co to Ni was increased, the width of the nanosheets gradually increased. Cyclic voltammetry (CV) at a scan rate of 50 mV/s showed that the Ni8–Co2 and Ni6–Co4 oxide samples exhibited better electrochemical performance than the other oxide samples. Furthermore, all Ni–Co oxide samples except Ni0–Co10 exhibited a reversibly sustainable in situ transmittance change with cycling (1000 cycles, 30,000 s) and a relatively fast switching time of less than 4 s for the colored and bleached states. Herein, the color modulation from transparent to black nanosheet-structured Ni–Co oxide samples was effectively tuned by adjusting the ratios of the Ni and Co precursors.journal articl