材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
70 巻, 7 号
選択された号の論文の12件中1~12を表示しています
資料
  • 河村 進, 中井 毅尚
    2021 年 70 巻 7 号 p. 515-521
    発行日: 2021/07/15
    公開日: 2021/07/20
    ジャーナル フリー

    To evaluate the temperature distribution of a roof receiving sunlight, we investigated a measurement method using a drone equipped with thermography. Since the number of pixels and shape of the contour of the captured roof images depend on the angle at which the photograph is taken and flight altitude of the drone, we standardized images into the same coordinate system by placing positioning markers on the roof before image capture. The visible image and temperature data for the roof were projective transformed. Differences in temperature measured by thermography and thermocouples attached to the roof were within the temperature accuracy range of thermography. Changes in roof surface temperature could also be measured by a thermograph mounted on a drone. We confirmed differences in temperature distribution among roof materials and part types, in part due to the uneven surfaces of the roof tiles.

論文
  • 田中 徹, 伊藤 貴文, 岩本 頼子, 三好 由華, 堀山 彰亮, 神代 圭輔, 古田 裕三
    2021 年 70 巻 7 号 p. 522-527
    発行日: 2021/07/15
    公開日: 2021/07/20
    ジャーナル フリー

    Heat treatment is one of the techniques to improve the resistance to decay and dimensional stability of wood. In this study, paid attention to those inorganic salt of NH4Cl and MgCl2, dilute NH4Cl and MgCl2 aqueous solution were impregnated into cedar (Cryptomeria japonica D. Don) sapwood and subjected to heat treatment at 160°C to 180°C, and then the decay resistance was evaluated by a decay test using Fomitopsis palustris. The mass loss rate by heat treatment was about 3% for the wood without impregnation, whereas the impregnated wood exceeded 11% under the treatment condition of 180°C, and the accelerated thermal decomposition by inorganic salt was observed. As for the decay resistance, the mass loss rate of wood without heat treatment was 57%, whereas NH4Cl impregnated wood was suppressed to about 10%, and there was no significant decrease in the decay resistance due to the leaching treatment. On the other hand, it was suggested that MgCl2 impregnation wood had a large decrease in the decay resistance by performing the leaching treatment in advance, and that the composition after the thermal decomposition differed depending on the inorganic salt used. In addition, NH4Cl impregnated wood showed higher resistance to decay with a lower mass loss than that for MgCl2 impregnated wood under the same temperature and the heat-treated wood under higher temperatures.

  • 田中 徹, 伊藤 貴文, 岩本 頼子, 三好 由華, 堀山 彰亮, 神代 圭輔, 古田 裕三
    2021 年 70 巻 7 号 p. 528-534
    発行日: 2021/07/15
    公開日: 2021/07/20
    ジャーナル フリー

    In previous studies, heat treatment was carried out at temperatures below 180°C by impregnating a dilute inorganic salt aqueous solution into cedar (Cryptomeria japonica D. Don) sapwood. As a result, water insolubilization of the decomposition products generated by heat treatment was suggested when NH4Cl was used. Therefore, we aimed to investigate the mechanism by which the decay resistance is improved by heat treatment using NH4Cl. The changes occurring in wood components as the decay resistance was improved were investigated. The following became clear as that result.The cold water soluble component ratio hardly increased and the absolute amount ratio of the acid insoluble component became higher as NH4Cl concentration increased, and the acid insolubilization of the pyrolysate was observed. In the heat treatment for 24 hours, there were linear relationships between the mass loss rates by the decay resistance and the heat treatment, and the acid insoluble component ratio and by the mass loss rate by the decay resistance, and the decay resistance was improved with the increase of the mass loss, that is with increase of and the acid insoluble component. The sample heat-treated with 2.5% NH4Cl at 150°C met the performance criterion for preservation specified in JIS K 1571. In the heat treatment for 72 hours, even a smaller mass loss rate and an acid insoluble component ratio compared with the heat treatment for 24 hours, the decay resistance was improved than that of the heat treatment for 24 hours. When heat treatment was carried out at a concentration of 1.0% and 170°C for 72 hours, the mass loss rate with heat treatment was 11.3% and the sample was satisfied the performance criterion for decay resistance.By using NH4Cl, the performance criterion for decay resistance was achieved by heat treatment at temperatures greatly lower and with decreasing mass loss by more than 7% than conventional high-temperature treatment conducted above 200°C.

  • 細川 璃紗, 仲村 匡司, 小林 秀平
    2021 年 70 巻 7 号 p. 535-540
    発行日: 2021/07/15
    公開日: 2021/07/20
    ジャーナル フリー

    Changes in appearance of every product by the aging are inevitable. Such changes are considered as the deterioration easily connecting to negative impressions to various products. On the other hand, the changes in the appearance of wooden products by the aging may create new aesthetic values such as “antique” and “vintage”. The objectives of the present study are to extract image characteristics related to the change in the appearance of lumber surface caused by the aging and to investigate relationships between them and sensory evaluation or attractiveness. Twenty-five quasi-aged wood specimens with 300 mm square were prepared by a skilled painter’s techniques. Digital image data with the true chromatic information of the specimens were captured by an imaging spectrometer and two kinds of image analyses were applied to the data. Forty university students evaluated the appearance of the specimens subjectively such as “antiquity” and “aesthetics by aging”, and the eye movements of another fifteen university students observing the specimens were recorded using an eye tracker. The surface lightness and its variation strongly affected the subjective antiquities of the specimens. The eye tracking revealed that the participants tended to gaze frequently at characters of a specimen surface such as distinct flat grain's vertexes or dirty stains.

  • 杉野 秀明, 田中 聡一, 笠松 由芽, 奥林 里子, 関 雅子, 三木 恒久, 梅村 研二, 金山 公三
    2021 年 70 巻 7 号 p. 541-546
    発行日: 2021/07/15
    公開日: 2021/07/20
    ジャーナル フリー

    The purpose of this study was to confirm the influence of bleaching on the plastic flow deformation of bulk wood irradiated by the electron-beam (EB). Flat-sawn wood samples of hinoki (Chamaecyparis obtusa) in the oven-dry condition were irradiated by EB at several levels of absorbed dose ranging from 0 to 263 kGy, and subsequently bleached using the mixed aqueous solution of hydrogen peroxide and ammonia. Free compression along radial direction of wood were performed on the treated samples at moist and heated conditions. The obtained strain-stress (s-s) curves indicated that the deformation behavior was affected by the bleaching as well as the EB irradiation. The proportional limit strain, flow starting strain, and maximum strain in the s-s curves indicated that the flow deformation was decreased by the bleaching and was promoted by the EB irradiation, though the elastic deformation and densification deformation were not affected by both treatments. The flow deformation along tangential direction of wood was decreased by the bleaching, while the deformation along fiber direction was promoted by the bleaching. It was shown from the scanning electron microscope (SEM) observation that the deformation along the fiber direction increased with increasing the number and scale of fracture of wood fibers. By the EB irradiation on the sample, the flow deformation became more easily started and was promoted till the end of the deformation. By the bleaching of the sample, the flow deformation became more easily started, however its progression was suppressed.

  • 安藤 桃子, 杉村 和紀, 上高原 浩
    2021 年 70 巻 7 号 p. 547-553
    発行日: 2021/07/15
    公開日: 2021/07/20
    ジャーナル フリー

    Liquid crystallinity of (hydroxypropyl)cellulose (HPC) derivative in aqueous solution was examined to develop eco-friendly liquid-crystalline system. Bulky adamantoyl group (adamantyl ester) was introduced as a substituent on HPC, and the effects of the degree of adamantoyl substitution (DSAd), polymer concentration, and temperature on the chiroptical properties, especially coloration and turbidity, of the aqueous lyotropics were investigated by circular dichroism, CD, and ultraviolet–visible–near-infrared, UV–Vis–NIR, spectrophotometry. Adamantates of HPC (Ad- HPCs) with extremely low DSAd (< 0.1) were successfully synthesized by acylation of HPC with 1-adamantanecarbonyl chloride in tetrahydrofuran. Ad-HPCs of DSAd ≤ 0.08 were highly soluble in water, and the concentrated aqueous solutions formed a right-handed cholesteric liquid-crystalline phase to impart vivid reflective colorations. The cholesteric helical pitch P, comparable to the wavelength of maximal reflectance λmax, increased with increasing DSAd of Ad-HPC and with decreasing polymer concentration. Wide-angle X-ray diffractometry, WAXD, revealed that the increases of P were attributable to the decrease of the twist angle ϕ between adjacent thin nematic layers. The aqueous Ad-HPC lyotropics were phase-separated and became turbid at an elevated temperature of > ∼30°C. Such a lower critical solution temperature (LCST)-type phase separation behavior of the Ad-HPC/water system was also affected by the hydrophobic adamantoyl group; the observed cloud point Tc was shifted to lower temperature side with increase in DSAd, presumably due to the heightening of hydrophobic interactions between the solute Ad-HPCs in water.

  • 宝角 春香, 吉岡 康一, 細谷 隆史, 宮藤 久士
    2021 年 70 巻 7 号 p. 554-560
    発行日: 2021/07/15
    公開日: 2021/07/20
    ジャーナル フリー

    Furan compounds, especially 5-hydroxymethylfurfural (5-HMF) and furfural (FF), are promising platform chemicals that can be produced from various lignocellulosics. This study presents production of the furan compounds from moso bamboo (Phyllostachys edulis) in an ionic liquid, 1-methylimidazolium hydrogen sulfate ([HMIM]HSO4), which acts as both solvent and acid catalyst during the furan compound production. Vacuum steam distillation (VSD) technique, which facilitates simultaneous removal and purification of the furan compounds, was combined to the process. Reaction of the bamboo sample (30 mg) in [HMIM]HSO4 (3.0 g) at 180 °C for 30 min at 20 hPa with continuous steam supply (3.1 mL/min based on liquid water amount) produced 5-HMF and FF in 20.6 and 11.4 wt% yields, which were significantly greater than the maximum yields of those compounds obtained in the experiment without the VSD equipment (5-HMF: 6.6 wt%, FF: 4.6 wt%). The furan compounds were recovered in a cold trap separated from the main reactor as an aqueous solution with significant purity. After 9 times recycling of the ionic liquid without any refreshing treatment of the medium, the yield of the furan compounds decreased by only 10~30 % compared to the initial yield with fresh [HMIM]HSO4. The small decrease in the yield was attributed mainly to the presence of bamboo-derived solid residue piled in [HMIM]HSO4 during the reaction.

  • 山本 健, 藤田 和彦, 渡辺 靖崇, 宮武 敦, 渋沢 龍也, 田中 聡一, 金山 公三
    2021 年 70 巻 7 号 p. 561-566
    発行日: 2021/07/15
    公開日: 2021/07/20
    ジャーナル フリー

    To promote the use of CLT, flexural property including anisotropy were examined. Specimens cut from Five-layer five-ply CLT constructed with Sugi (Cryptomeria japonica D. Don) were used for out-of-plane bending test. Results both in major and minor strength direction are summarized as follows: 1) The strength in minor strength direction specimens should be evaluated as 4 laminar structure except the most outer laminar. 2) As for major strength direction specimens, it was suggested that the strength was affected by Mechano-sorptive creep. 3) In the case of minor strength direction specimens, consideration of Mechano-sorptive creep was thought not to be necessary. 4) The duration of load factor of CLT was almost equivalent to the duration of load factor commonly known for solid lumber.

論文
  • 原 圭介, 中谷 隼人, 今中 誠, 河野 洋輔, 池田 徹
    2021 年 70 巻 7 号 p. 567-572
    発行日: 2021/07/15
    公開日: 2021/07/20
    ジャーナル フリー

    Structural acrylic adhesives have been attracted special interest because theses adhesives can be cured at room temperature and can be bonded to oily substrates. To use adhesively bonded joints more widely for structural use, it is necessary to clarify fatigue crack propagation characteristics. In this study, fatigue crack growth rate was measured using adhesively bonded unidirectional and woven CFRP/aluminum double cantilever beam (DCB) joints with an acrylic adhesive. To elucidate the difference of fatigue crack growth rates between adhesive joints with unidirectional and woven CFRP adherends, finite element analysis was conducted for these joints, wherein Gurson's model was applied to the adhesive layer. The differences of fatigue crack growth rate can be elucidated from the distributions of void fraction in front of the crack tip for the both joints.

  • 杉本 達洋, 石塚 師也, 林 為人
    2021 年 70 巻 7 号 p. 573-580
    発行日: 2021/07/15
    公開日: 2021/07/20
    ジャーナル フリー

    One of the problems of in-situ stress measurements is that they cannot determine the uncertainty of the results. In this study, we propose a new analyzing procedure of anelastic strain recovery (ASR) method, one of the in-situ stress measurements, enabling us to conduct uncertainty quantification (UQ) based on Bayesian statistical modeling (BSM). This research consists of two stages. In the first stage, reported in this paper, we construct a new procedure and apply it to simulated ASR data to investigate its characteristics. In the second stage, we will examine its applicability using real ASR data. The new procedure consists of the following three steps: i) measuring the ASR of a rock core sample with strain gauges, ii) applying a probability model based on BSM to the measured ASR data and simulating the probability densities of the elements of an in-situ stress tensor and other parameters, iii) regarding the probability densities as the results of in-situ stress measurements with uncertainty. This paper shows the results obtained by the new procedure applied to simulated ASR data. The results show that the uncertainties of some parameters reduce by giving the elastic moduli. On the other hand, the rates of decrease in the uncertainties vary for each parameter. To reveal the cause of these differences, we introduce a new evaluation item of Sobol’ indices, one of the global sensitivity analyses, and make quantitative discussion.

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