Wind Tunnel Study on the Shelter Effect of Windbreak Nets with Different Weaving Types

摘 要 台灣嚴重風害之防杜，防風網扮演著不可或缺的角色。防風網之應用相當廣泛，常用於沿海地區、山坡地、耕地及防風林前期保護帶等；惟其型式眾多，且附加功能及成本均有差異，現今台灣卻無相關研究及資料可供參考；有鑑於此，本研究針對台灣市場占有率較高之平織、針織及羅紋織等3種不同編織形式防風網，進行風洞模擬試驗，分別以相對風速、減風係數、保護指數及經濟效益比較分析盼能將此3種不同編織形式防風網加以比較，爾後提供工、農業選用上之參考依據，探討其減風效果，成果如下： 1. 平織、針織及羅紋織等3種不同編織形式防風網之防風效果，在通透率相同時，平織編織成型之防風網最具功效，羅紋織編織成型之防風網次之，最差者為針織編織成型之防風網。 2. 防風網背風面於防風網高度（H）之2H～10H處，減風效果達最大，而後隨水平距離之增加減風效果亦隨之衰減，防風網垂直高度1.7H以上，已無減風效果，且會造成氣流加速作用，則防風網迎風面2H處，5種防風網皆因模型設置引起流場抬升所產生的擠壓效應而風速略減，此現象與理論相符合。 3. 當通透率及編織形式相同時，針織網目呈三角形之防風網，其減風功效高於網目成矩形；羅紋織緯紗4條之防風網，其減風功效高於緯紗2條之防風網。 4. 3種編織形式之防風網型號皆具備防風功效，若須附加遮陽功能應選用針織及羅紋織，其中羅紋織效減風效果較佳，若須附加防蟲功能應選用平織及針織，其中平織減風效果相對較佳。 5. 防風網型號32目網紗在5種防風網中成本僅高於防風網型號B1010，但其減風效果是5種防風網之冠，建議現地防風網施作若無遮陽應用上，應選用防風網型號32目網紗。Abstract Windbreak net is an important role to prevent crops and plants in Taiwan. It is used often at coastline, hills, farms, and earlier stage of a Windbreak net forest, etc. There are many types of Windbreak net, but lack of directions and researches on using them correctly. In consideration of this study analyzes 3 Windbreak net types of higher market share in Taiwan, plain weave, knitted and ribbed weave, to proceed wind tunnel simulation experiments, Compared the relative wind speed, wind speed reduction coefficient, protection index and economic benefits respectively. They're hope for provide industrial and agricultural use on a reference to explore the effect of reducing the wind, the following results: 1. Density of the same in three different types of plain weave, knit and ribbed weave, the plain weave type stands the most affectivity, knit type woven follows, and ribbed type woven the least. 2. The maximum wind speed reduction oppeared in the leeward distance with 2H-10H of Windbreak net net height(H), then reduced with the increase of horizontal distance along the wind effect is also attenuated, wind net over a vertical height of 1.7H, the wind effect no longer reduced, and the lead role of flow acceleration , the wind net windward 2H Department, five kinds of wind because the model set net uplift caused by the flow field generated by the squeeze effect and the wind speed slightly reduced, this phenomenon consistent with the theory. 3. While the density and the knitting method are the same, wind speed reducing of triangle-shaped shelter is more effect than rectangle-shape one. Ribbed weave of 4 wefts is more effect than that of 2 wefts. 4. 3 types of knitting net are effect on wind reducing, it is suggested to choose knit and ribbed weave nets if the shading function is requested, where the ribbed weave performance a better wind reducing effect. Woven and knit woven are selected if insect function is required, and woven is the better than knit woven. 5. Windbreak net mesh model 32 mesh gauze nets in five kinds of wind just above the Windbreak net net cost model B1010, but the effect of reducing the wind effect is one of the best. This proposal is now to be without shade Windbreak net network for applications, network models should be used 32-mesh wind yarn.目 錄 摘要…………………………………………………….……………...... І Abstract………………………………………………….……………....Ⅲ 符號說明表…………………………………………….……………....ⅩІ 第一章 緒論 1 一、研究緣起 1 二、研究動機 2 三、研究目的 3 四、研究流程 4 第二章 前人研究 5 一、風洞試驗流場之相關研究 5 （一）大氣紊流模擬 5 （二）流場阻塞效應 6 二、防風網之相關研究 7 （一）防風網密度 7 （二）減風效果 8 第三章 材料與方法 10 一、風洞設備儀器與量測儀器 10 （一）風洞設備 10 （二）皮托管(Pitot tube)量測儀器 12 二、模型設計 14 三、模型設置 22 四、試驗方法 22 （一）風速採樣點 22 （二）試驗風速 23 （三）迫近流場之模擬 23 （四）相對風速 24 （五）減風係數 24 （六）保護指數(P.I). 25 第四章 結果與討論 26 一、風速剖面之探討 26 二、相對風速之探討 34 三、減風效果之探討 34 （一）各防風網減風效果之整體分佈 34 （二）相同測高之防風網減風效果比較 50 四、防風面積之探討 59 五、經濟效益之探討 67 第五章 結論與建議 69 ㄧ、結論 69 二、建議 70 參考文獻 7

探尋精神分裂症的易感基因:以rgs4為例

Schizophrenia is a serious neuropsychiatric illness that has a strong genetic component and high heritability. Many researchers favor a multilocus model for schizophrenia, in which epistasis of several genes leads to the disorder. Regulator of G protein signaling 4 (RGS4) is one of the susceptibility genes of schizophrenia identified by linkage and association studies initially, and is further validated by expression and functional studies. The function of RGS4 is closely linked to the pathological mechanism of schizophrenia. We have reviewed literature up to date and try to clarify the following issues: (1) the mechanism of RGS; ( 2) the structure of RGS4; (3) the function of RGS4; (4 ) the association between RGS4 and schizophrenia. We hope the model of identifying RGS4 as a susceptibility gene for schizophrenia can provide researchers a better understanding to link a gene to a complex disorder like schizophrenia

Effect of Soil Management and Applying Fertilizer Technique on Mutrient Balance and Physiological Barrier of Some Crops under Soils with Limiting Factors or Special Characteristics

本計畫旨在解決地區重點作物土壤與作物之養分平衡問題、養分有效率及肥力之動態平衡等相關之品質產量與後熟品質問題等。包括地區重點作物土壤特性、管理之調查分析及作物性狀、營養特徵與產量間相關之調查分析與診斷；地區性土壤之水分、養分供應能量與強度因子分析，擬定初步作物營養生理障礙解決方案。 The objective of this project is to study the effect of soil management and fertilizer controll on increase of crop yields and quality, and establish the adaptive techniques in applying fertilizer and improvement of nutrient efficience and balance for soils with limiting factors or special characteristics. The field experiments has been conducted on sandstone and shale alluvial soils in the farm of TARI and other soils with limiting factors or special characteristics such as shallow depth soil, coarse texture, high P-fixation soil, nutrient unbalance in capacity and intentity. . The treatments for residue are composed of residue incorporation, residue burning and residue removal in the field experiments of TARI in order to compare the P efficience with that of black soil.under rice culture.. The other soil survey and field invetigation include soil pH, texture, drainage condition, exchangeable calcium and magnisium content, organic matter, micronutrient and balance of available nutrient. The effects of fertility and quality of irrigation water are also monitored in this study. It is expected with finishment of this project, techniques for appropriate soil management methods will be established to maintain the development of sustainable production with high crop qualitity. On the other hand, this research also study the effect of cropping, organic manure. green manure crop, and other soil managements on the changes of available nutrients, especially for the balance between soil nutrients

防風網編織形式對減風效果之風洞試驗研究

Windbreak Net is an extremely important facility of prevention of wind damage; however, windbreak net's function varies with different types; hence, the research's main purpose was to compare the differences of shelter effect with diverse windbreak net weaving types. The research adopted three types of windbreak nets of higher market share in Taiwan: plain weave, knitted weave, which had two different mesh shapes, and ribbed weave, which had two varied weaving methods. The wind tunnel test was conducted with these five sets of windbreak net, and relative wind velocity, wind velocity reduction coefficient, protection index, and economic benefit were used respectively to do comparison and make analysis to explore the influence of weaving type, mesh number and shape on wind velocity reduction effect.The test results showed that when all windbreaks had the same ventilation rate, the windbreak net of plain weave had the best shelter effect, the secondary was ribbed weave, and the worst was knitted weave; however, if both the shading and anti-insect functions were required, the windbreak net of knitted weave type was relatively more ideal to choose; yet if taking economic benefit into consideration, the windbreak net of ribbed weave was the cheapest. As for the mesh shape, triangle had better shelter effect than rectangle, and in this research case, mesh number had no significant difference in wind velocity reduction.防風網是風害防治極為重要之設施，然而防風網之功能因其形式不同而異；因此，本試驗主要目的即在於比較防風網編織形式對減風功效之差異，研究中採用國內市占率較高之平織、針織及羅紋織三種形式防風網，其中針織有兩種不同網目形狀，而羅紋織則有兩種不同編織方式，將此五組防風網，進行風洞試驗，分別以相對風速、減風係數、保護指數及經濟效益比較分析，探討編織形式、網目數量及形狀對減風效果之影響。經試驗結果顯示，當透風率相同時，在減風功效方面，以平織形式之防風網最佳，羅紋織次之、針織最差；然而若需兼具遮陽及防蟲功效，則應選用針織形式之防風網較為理想；但若考量經濟效益，則又以羅紋織防風網最為價廉。至於網目形狀以三角形比矩形有較佳之減風功效，而網目數量在本試驗個案中，對於減風並無明顯差異