著者

高倉 直

出版者

養賢堂

巻号頁・発行日

vol.83, no.9, pp.953-957, 2008 (Released:2011-12-19)

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耕地からの蒸発散量を環境要因から算定するとき、そのすべてが耕地のエネルギー収支式から始まっていることは明らかである。すでにいくつかの手法が報告され、その改良法等も報告されている。歴史的に見れば、Penman-Monteithの式があまりにも有名である。50年以上も前にPenmanが植被のない状態での式を提案し、その後、Monteithが植被を含む場合にも適用できるように改良し、多くの論文や書籍等に紹介され、多くの研究に用いられてきた。このように、エネルギー収支式の残余項として求められることは明らかなことで、誰でも気が付くことであるが、最近放射温度測定が手軽になったにもかかわらず、この手法は意外に研究されていない。温室内や限られた面積の耕地の場合には、広大な面積に用いられる手法は適切とは言い難く、これまで水蒸気フラックスを測るPenman-Monteith法やボーエン比法が多く用いられているのが現状である。もう1点、重要なことは、蒸発散の算定は単に、耕地の微気象解析そのものが目的であるばかりでなく、それに基づく植物群落への灌水制御という側面があることである。そのためには、高価な測器を使うことなく、また限られた面積の植物群落にも適応出来る手法が望ましい。

著者

仁科 弘重 高倉 直

出版者

The Society of Agricultural Meteorology of Japan

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.39, no.3, pp.201-211, 1983-12-10 (Released:2010-02-25)

参考文献数

12

被引用文献数

2 2

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As the first step of a study on solar greenhouses with latent heat storage systems, thermal properties of phase change materials (PCMs) were tested and solar heating experiments applying these PCMs to small greenhouses were performed.Several PCMs which have melting points between 10-30°C were selected from the literatures (e.g. Hale et al., 1971), and measurements of melting points and heats of fusion were made. Considering these test results (Table 1 and Fig. 1), and because of the extremely high price of paraffin, we chose polyethylene glycol (PEG) and calcium chloride hexahydrate as the most suitable PCMs for solar heating greenhouses at the present time.Three types of solar greenhouse systems were constructed, and solar heating experiments were performed in both 1979 and 1980. We used two small identical glasshouses (floor area is 7.2m2, surface area 25.2m2) with the north wall (4.8m2) insulated.In the Type I solar greenhouse (without thermal screen), polyethylene tubes (3.0cm in diameter) were filled with 600kg of PEG (# 600 and # 400) and hung by steel bars in the insulated heat storage unit. Air was circulated by a fan between the greenhouse and the heat storage unit, and solar heat was collected from the air inside the greenhouse (Fig. 2). Typical patterns of diurnal changes in temperatures in the Type I solar greenhouse on a clear day are shown in Fig. 3. Solar heat stored in the daytime was 9, 900kcal and heat released in the nighttime was 11, 060kcal. The average efficiency of heat storage on clear days was 20%, based on the outside solar radiation.In the Type II solar greenhouse (with one layer thermal screen), three 1.6m2 air-type solar collectors were attached. PCMs, 300kg of CaCl2⋅6H2O and 200kg of PEG (# 600), were encapsulated in double-layered polypropylene panels (1.2cm in thickness) and were installed in the heat storage unit. In the daytime, air was sucked from the greenhouse to the collectors, and heated air was then sent to the heat storage unit and was returned to the greenhouse. In the nighttime, the path to the collectors was closed by a damper, and air was circulated between the greenhouse and the heat storage unit, although the direction of the air flow through the heat storage unit was opposite to that in the daytime (Figs. 4 and 5). The heat collected in the collectors was 12, 060kcal, and the heat stored in the heat storage unit was 8, 380kcal (7, 520kcal to CaCl2⋅6H2O, 860kcal to PEG) on Feb. 3, 1980. The temperatures of CaCl2⋅6H2O and PEG were kept almost at the melting point of each, which indicated that the storage capacity of latent heat was not yet filled. The inside air temperature was kept at 8.0°C in the early morning on Feb. 4, when the outside air temperature was -0.6°C. The average efficiency of heat storage on clear days was 17%, taking into account the receiving area of both the collectors and the greenhouse.In the Type III solar greenhouse (with one layer thermal screen), double-layered polypropylene panels (1.5cm in thickness) which contained 56kg of CaCl2⋅6H2O were installed in front of the inside surface of the north wall. They could be called a heat storage panel. In addition to this, 200kg of PEG (#600) was encapsulated in PVC pipes (3.2cm in diameter) and was installed in the small heat storage unit. The heat storage panel can store heat from direct solar radiation. In the heat storage unit, heat was collected from the inside air by circulating air between the greenhouse and the heat storage unit. Typical patterns of diurnal changes in temperatures in the Type III solar greenhouse on a clear day are shown in Fig. 6. The heat stored in the heat storage panel and the heat storage unit was 2, 860kcal and 7, 560kcal, respectively.

著者

孫 禎翼 高倉 直

出版者

The Society of Agricultural Meteorology of Japan

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.44, no.4, pp.253-258, 1989-03-10 (Released:2010-02-25)

参考文献数

14

被引用文献数

9 10

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For investigation of the relationship between plant growth and environmental factors in a plant factory, an experimental plant factory has been built and some experiments have been carried out. Leaf lettuce was grown in a hydroponic system under artificial light condition. Arial environment such as air temperature, humidity and CO2 concentration were controlled. Root environment such as EC and pH were monitored and controlled by a microcomputer.In the first experiment, EC level was maintained at a constant set-point and the difference between the set-point and the actual value was summed up when the latter value was corrected. Transpiration was also calculated from the water depression in the tank. Then it was summed up through the growing period.Following results were obtained:(1) The EC decrement showed high correlation with the transpiration, regardless of light intensity and (2) the transpiration rate per EC decrement decreased as the EC of nutrient solution became higher.In the second experiment, the effects of light intensity, lighting cycle and EC of nutrient solution on tipburn injury were examined.Following results were obtained: (3) The tipburn occurrence became later under the conditions that the EC was low and the duration of a lighting cycle was short and (4) the tipburn occurrence became later under the conditions that the light intensity was low and the duration of a lighting cycle was short.Effect of the duration of a lighting cycle on the tipburn occurrence showed larger as the light intensity increased. From the results of Tibbitts et al (1985), it is, therefore, considered that the pressure of laticifer or the Ca concentration in the wall of laticifer increases with the increase of the duration of lighting cycle and this could cause the tipburn.

著者

高倉 直 高尾 雄二 武政 剛弘 池永 敏彦 平岡 教子 中村 武弘

出版者

長崎大学

雑誌

基盤研究(B)

巻号頁・発行日

1998

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Agave pasificaの苗の大量増殖を目的にin vitroで基礎実験を行い、その実験結果からジャーファメンタでの培養を行った。無菌種子から育てた葉の厚さ5mmの外植片をMS培地を修正した培地にホルモン(2,4DとBA)を添加し、蔗糖と寒天を加えた培地で培養した。いずれの培地においてもカルスが誘導され、生長も良好であった。その後、継代のカルスの生長培養条件を調べた結果、2,4Dを0.25mg/LとBAを10mg/L添加した培地で生長が最も良好であった。カルスからシュートの形成では、再分化した植物からはシュートとともに根を形成した植物も出現したが、しないものはホルモン無添加の培地に移して発根させた。12回継代培養を重ねたカルスからはシュートは形成されなかった。ジャーファメンタによる大量培養では、培養液として、大塚1号、2号の混合標準培養液を用い、25℃、暗期で3週間培養した。発芽率は対照区よりジャーファメンタを用いた場合が高くなる傾向を示したが、植物の生長に個体差が大きく均一性に欠けた。Agave pasificaはCAM植物であり、通常のC3、C4植物とは異なる光合成を行うので、その光合成をsimulinkを用いてモデル化した。二酸化炭素固定の第1ステップはメソフィル細胞で起こる。C3あるいはC4植物は明期にCO_2を取り込むが、CAM植物は暗期にCO_2を取り込む。CAM植物はC3植物に似た光合成を行う。4つのプロセスからなる。1)気孔をひらき、CO_2の固定、2)リンゴ酸の合成、3)リンゴ酸の消費、4)C3光合成である。光合成におけるカルビンサイクルは3つの生化学反応として表現できる。まず、第1はRuBPとその中間生成物(R)の合成である。Rはミカエルーメンテンの関係式に従うとして、各種の光入力に対して光合成がどのように変化するかをモデル化した。

著者

庄野 浩資 天羽 弘一 高倉 直

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.45, no.2, pp.87-92, 1989-09-10 (Released:2010-02-25)

参考文献数

7

被引用文献数

1 2

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A method to detect cucumber fruits in the canopy using image processing technique has been studied, with the aim of robotic harvesting. This method distinguishes a fruit from the other parts of the plant, not by the difference in their colors, but by the difference in shapes.The brightness in the digitized image was differentiated in horizontal direction, and clipped into three values (+, 0, -) by two thresholds. Then ridge-lines were drawn between (+) value area and (-) value area.The ridge-line images ordinarily contain some noise from the other parts of the plant. Accordingly, two images for the same scene were taken, one was illuminated from the left and the other was illuminated from the right. The center line image was obtained by comparing the two ridgeline images in consideration of the shift of the fruit's ridge-line which was calculated by a model. After the noise was reduced in the center line image, the center line of the fruit remained.This method contains four unknown parameters, and it was found that these parameters have the optimum value. But there were some deviations in the optimum values obtained from different images. The deviations were not so severe as to make the detection impossible in our experiment, but in general it is necessary to determine the optimum values applicable to many other scenes.This method was applied to some images taken in the field, and showed that it was able to detect the fruit when it was fully illuminated from both sides. The detection, however, became difficult when the light was intercepted by leaves and the illumination for the fruit was not enough.

著者

杉 二郎 井上 裕雄 田中 純生 野口 勝一 高倉 直 小穴 敬喜

出版者

Japanese Society of Agricultural, Biological and Environmental Engineers and Scientists

雑誌

生物環境調節 (ISSN:05824087)

巻号頁・発行日

vol.1, no.2, pp.94-99, 1964-04-30 (Released:2010-06-22)

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ここに紹介されている小型のファイトトロンの特徴はプラスチック材料を用いることにより太陽光の透過がずっと能率的になっていることと, 材料が軽いので破損の危険が少ないことの2点である.プラスチックの透明な屋根は122/3×163/4ftの広さで, 傾斜角度が23°で北側に13ft, 南側に9.2ftの長さがある.屋根は141/2×2ftのプレキシグラスのパネルを用いて断熱のために二重構造になっている.プラスチックの各層の下側の表面はプリズムになっていて, 太陽光を植物体に投射できるように設計されている.東, 西, 南側の壁も二重のプラスチックでできており, 外側は透明で内側は光を散乱するようピラミッド型の模様がつけられている.自動的に働くスプリンクラーから出る水が1日2回屋根の塵を流し去るようになっている.アルミニウム製の金具がプラスチックの屋根を支えており, 鉄線の張りを調節することにより真直に保てる.この金具によって屋根より入る太陽光の約8%が遮断されるにすぎない.プラスチックでできた両側の壁からは太陽の位置が低い早朝および夕方の光が室内に入るようになっており, とくに冬期にはその効果が著しい.春分, 秋分のとき, 1日平均して屋外の太陽エネルギーの約50%が室内のベンチの面でえられる.室内の日蔭の部分は朝から夕方にかけて平均化されるので, 各部分はほぼ同じ量の太陽エネルギーを受げる.両側面の窓の上下の部分の多くの孔をあけた壁および窓の高さに縦についた溝より, 調節された空気が出て, 東から西へ流れる.水平の溝と方向づけの羽根で室内のどの部分の空気の流通をも調節しうる.このファイトトロンを用いて太陽光の利用度, 調節用の動力経費, 室内での植物の生育状態などが現在調査されている.さらに太陽の位置の変化に応じて自動的に回転する効果的なファイトトロンも考察されている.