全國中小學科展

2004年

Tamarind(Tamaridus Indical.)Seed Coat Extracts As Coconut Oil Antioxidant

After short period of storage the coconut oil at room temperature we found that it becomes rancid. The oxidizing flavor is disgusting and causes economic loss. Some chemicals are used to prevent the oxidation of coconut oil but they are expensive and may be harmful to consumer’s health if used daily. Moreover, they are not suitable for homemade coconut oil and residual waste from the process may be environmental toxic. The present work thus aims at extracting substances from local plants and used as antioxidant for coconut oil. Seven kinds of local Caesalpiniaceae plants in Eastern Thailand namely Tamarind (Tamaridus indica L.), Peacock flower Caesalpinia pulcherrima L.), Flame tree (Delonix regia L.), Golden shower (Cassia fistula L.), Siamese cassia (C. siamea Lamk.), Candelabra bush (C. occidentalis L.), and Copper pod (Peltophorum pterocarpum DC.) were used. Ten grams of seed coats were mixed with 50 ml of the distilled water and 95% Ethyl alcohol (1:1) mixture in a closed container. The mixture was heated in a water-bath at 60 ℃ for about 2 hrs. and then kept in 10 ℃ icebox about 2 hrs. The mixture was then filtered and the filtrate was heated in an hot-air oven at 80 ℃ for about ? hrs. Ten ml of coconut oil was added with 0.5g of the extracts and kept at room temperature for 5 days. The pH and peroxide value (using the Iodometric titration method) of the oil were measured. It was found that the coconut oil with the Tamarind seed extract had the lowest peroxide value and was selected. Next the suitable amount of the Tamarind extract was studied by adding the extract to 10 ml coconut oil at 0-7% (w/v) and the contents were kept at room temperature for 5 days. The result showed that the 3% (and more over) Tamarind extract had the lowest peroxide value. Then the coconut oil with 3% Tamarind extract was kept at room temperature for 30 days. The pH and peroxide value were measured every 5 days. It was found that the oil could be stored for 25 days without significant change in pH and its peroxide value was less than 10 milliequivale n t oxygen per kilogram oil according to FAO/WHO (Codex) standard .Therefore, Tamarind seed coat at 3% could be used to retard the coconut oil oxidation for 25 days. This work presents the applicable use of plentiful local plants such as Tamarind seed, which is normally discarded, as an antioxidant for coconut oil.

正弦桿精確度挑戰與探究

Sine bar is precise measuring angular tool with gage blocks.Basica1 旬, to get height we calculates with H=L×sinOto assemble gage blocks.It is inconvenient to assemble gage blocks and maintain after we measured when wanting to get different dimensions. In out wOItwe have fabricated rap1d positioning sine bar by combining micrometer and sine bar.The purposes ofthis research are producing dimensions accurately and rapidly.Thus,it won't have errors when workp1eces are mached and measured. 正弦桿是測量角度的精密量具,基本上,正弦桿需跟塊規組合使用,再利用H=L Sinθ 算出需組合之高度,在算出需用何種尺寸之塊規需用幾塊,但如果遇到多種不同高度時,則需要更換不同尺寸之塊規,塊規在每次使用時都需清潔乾淨,十分的不方便,在此我們利用測微器,與正弦桿結合,捨去塊規,研製出快速定位正弦桿。此一設計主要包含有原本的正弦桿,一支測微器,結合成新的正弦桿,本正弦桿主要的特性是,在每一種高度算出後,即可利用正弦桿上的測微器直接旋轉到需要之高 度,且轉到需要之高度後可將測微器固定讓測微器不再旋轉,且兩者是一體的,不會出現測量或是加工時,正弦桿移動之現象,使用中也不會去觸摸到測微器之測頭而產生了熱脹冷縮之誤差發生,達到快速定位之需求。

從小玩意探討大問題-磁浮隔空旋轉器的轉動情形與磁場變化之研究

磁浮隔空旋轉器是由一個旋轉軸和底座構成,利用兩者間相互排斥的磁力, 產生隔空漂浮的效果。本研究首先對旋轉軸的結構加以分析,並設計啟動裝置, 探討啟動電壓、旋轉軸重量及底座磁力等因素對漂浮轉動的影響。 我們分析維持旋轉平衡的各種作用力,並探討旋轉軸重心位置與摩擦力的關 係,以驗證我們的分析結果。此外,我們也利用自行設計的啟動裝置,提供穩定 的初始轉速,探討旋轉軸重心位置不同時,持續轉動時間的變化,進一步驗證所 做的分析。 為了瞭解磁場在旋轉軸漂浮過程中發生的變化,我們設計了支架把空間座標 化,再以高斯計測量出各點的磁場,獲得各平面的磁場強度分佈圖。配合磁力線 分佈圖與所測得的磁場強度分佈圖,我們以一個嶄新的分析模式,將抽象的磁場 概念具體化,使我們對旋轉軸放置前後及磁力與重力平衡時的磁場變化,更深入 的了解,同時也發現磁場強度會隨距離的增加而減弱。 最後我們在旋轉器上裝置感應線圈,經由旋轉實驗測得感應電壓的存在,證 明旋轉器轉動時,磁場會產生變化。 經由對磁浮隔空旋轉器的探討,我們得以了解它的漂浮原理、磁力與摩擦力 間的平衡關係,以及旋轉前後磁場變化。The Magnetic Floating Spinner(MFS) is composed of one spinner with a magnetic base. The floating effect of the spinner is caused by the interaction between the two opposite magnetic fields. We first analyzed the detail structure of the MFS, and then designed a starter to rotate it. Later, we studied the effect of starting electric potential, the weight of the spinner and the magnetic force of the base on the floating movement. We presented an explanation for the forces that maintained the floating of the spinner and, to support that, we studied the friction force with the position change of the spinner gravity centre. We also used the starter designed by us to provide a stable initial rotating force and analyzed the relationship between the change of gravity centre position and the duration of rotation. In order to understand the magnetic field change during floating movement, we designed a spatial frame to coordinate the spinner that floated above the base. We measured the surrounding magnetic force with the Goth’s apparatus and conducted a magnetic force distribution diagram. According to this diagram and the line of magnetic force, we therefore provide a brand new analysis model , which bring the abstract concepts of the magnetic field into a concrete theory. This research not only brings us to understand the magnetic field change of the spinner before and after its placement over the base and the balance between the magnetic and the gravity force, but also reveals that the magnetic force will wane with the increase of distance. Finally, we placed an induction coil by the spinner to detect a voltage change during spinner movement. This is an evidence that the magnetic field will change during the spinner movement. Through the study of MFS, we can now understand why it floats, the balance between magnetic and friction force, and the change of the magnetic force before and after the spinner movement. MFS = Magnetic Floating Spinner

座標平面上任三點與X 軸之最短距離和

我們的題目是”座標平面上任意三點與x軸的最短距離和”。我們一開始直接由尺規作圖著手,把距離和最小時的那點設為p,但始終無法找到一個方法精確畫到p點。後來變轉入公式的研究,我們設第一象限中A B 和C三點,固定A B C的y座標為d,並討論不同d時的情況,求出B點的範圍。另外我們也從橢圓方面著手,但此部份目前還待努力。;A B and C are three points in the plane, and L is a line in the same plane. Our target is to find a point P in L make the sum of PA+PB+PC minimum. At first we undertake by drawing pictures but we can’t find the solution we want in any case. We make L to be X-axis make A B C’s Y-coordinate to be d, and then we discuss various situations of d, and figure out the range of B. We also analyze the situation in oval, but still have no conclusion.

Study Biological Deoderization using Bacteria in Rumen of Ostrich

Although it is well known that, unlike the feces of a fowl, those of an ostrich\r do not produce foul smell, the impact of different enterobacteria on elimination of malodorous\r substances has not been seriously investigated. I sought to test the hypothesis that ostrich\r enterobacteria (OE) are useful to eliminate hydrogen sulfide (H2S) and ammonia (NH3), two\r important components of foul smell of the feces.

數字波的節點探討

數字波是探討在直線上的起始點、位移速度、總數相互變化的節點關係。在直線上,將全部格子數做為總數(m),開始彈跳的點為起始點(i),每次彈跳的格子數為位移速度(s),被踩到的格子就是節點。節點是由位移速度和起始點決定,起始點本身可視為節點之一,之後的節點是由起始點加n 個位移速度產生。我們分別以三種型式討論:起始點等於位移速度,總數增加:使起始點和位移速度所代表的數字相同的彈跳。節點呈2、s、s+2…起始點固定,位移速度與總數增加:觀察位移速度和總數的關係。兩節點的和=s+2位移速度固定,起始點與總數增加:探討起始點和總數的關係。發現節點隨起始點有規律的變化在上述討論的型式中,我們再進一步將位移速度分為質數和合數,進而依其因數變化,可觀測到很多特殊的節點變化。The number wave is to discuss the relationship of the starting point, the moving speed, and the variations of total amount. In straight lines, let all the trellises be total amount (m), and let the starting jumping point be the starting point (i). The trellis number of each jump is the moving speed(s). The trodden trellises are knots. And knots are decided by the moving speed and the starting point. The starting point itself can be viewed as a knot. The following knots produce with the starting point and n moving speeds. We respectively discuss them in three types: When the starting point equals the moving speed, the total amount increases. The number of the starting point is the same with the jumping moving point; the knots are 2, s, s+2…. When the starting point is fixed, the moving speed and the total number increase. From observing the relationship between the moving speed and the total number, the sum of two knots is s+2. When the moving speed is fixed, the starting point and the total number increase. After our research into the relationship between the starting point and the total amount, we find the knots have regular variations with the starting point. From the types discussed above, we further divide the moving speed into prime numbers and non-prime numbers. Furthermore, according to the factor variations, we can see a lot of specific knot variations.

Energy-Transformation Railway System

There are numerous problems caused by today's railway system. This makes Hong Kong a less attractive place to live in. We have to tackle these problems in order to make Hong Kong a better place. Our model can recycle the energy dissipated in the rail vibration, reuse the sound energy produced by the wheels and the rail by a sound energy conversion system, recycle the wind power in the tunnel by a new type of wind turbine, the Wind Power Generator Underground (WPGU), recycle the thermal energy produced by the air-conditioning system of railway stations by a new system, the Thermal Energy Conversion (TEC). When the rail is bent, the magnets attached to it are also pulled down. When the rail returns to its original position, the magnets attached to it are pulled out of the coils. In both cases, the magnets move against a force. The work done to move the magnets against the force is converted to electrical energy. Also, the bottom of the MTR is designed to be curved. The sound waves produced by the contact point of the wheels and the rail directing towards the bottom of the MTR would be reflected to an elastic material which has a number of magnets attached to it and corresponding number of solenoids are fixed on the ground below the magnets. Sound energy can be converted to electrical energy in this case. When a train approaches or passes through the section that the WPGU is installed, wind is generated. The wind forces the wind turbine to rotate at a certain high speed. The turbine transmits the rotation to the coils in the dynamo, and hence electricity is generated. Heat released from the air-conditioner is absorbed by water. The hot water is then pumped into the system. As the hot water in the pipe flows through the evaporator, liquid ammonia inside will evaporate and flow into the electricity generator. Inside the electricity generator, the gas will push the turbine to rotate and hence electricity is generated. The ammonia gas is then condensed in the condenser and flows back to the evaporator. Hence ammonia is used circularly. In order to explain our principle, we would like to introduce the Lenz's Law, an induced current flows in such a direction as to oppose the movement that started it, the Faraday's Law of electromagnetic induction, the induced electromotive force in a circuit is equal to the rate of change of magnetic flux through that circuit, the Law of Conservation of Energy, energy can neither be created nor destroyed, but can transform from one form to the other.

渡溪探訪拉都希

本研究自2002 年4 月至2003 年5 月為止,共14 個月,於台北市金面山區\r 南麓溪谷及生態池,以Twitty 去趾法(toe-clipping method)對拉都希氏赤蛙(Rana\r latouchii)進行族群特性和生殖策略之研究。\r 研究期間內共標記了580 隻(包含畸形蛙65 隻),而雌蛙有190 隻(包含雌畸\r 形蛙19 隻),雄蛙有350 隻(包含雄畸形蛙43 隻),無法分辨公母者有30 隻(無畸\r 形蛙),未判定公母者有10 隻(包含畸形蛙3 隻)。\r 在族群特性的部分,拉都希氏赤蛙之雌、雄個體吻肛長、體重及吻眼比皆\r 有顯著性差異(p

棋子跳躍問題

This is a study about the solution to a chess flipping game. The game is based on a 4*4 game grid. First, place some chesses on the grid randomly to start a game. Move any chess by jumping over one or two neighboring chesses in the same row (left or right), same column (up or down), or on the same diagonal. Chesses which get jumped over should be flipped. The ultimate aim is to make all the chesses upside down. In this study, I try to find the rules of the beginning arrangement that ensure solution. Here are the steps I take: First, break the restriction of the 4*4 grid, and set the coordinate system. Second, find out a few “basic illustrations” that can be solved and moved in order to cope with certain complicated problems. Third, with “basic illustrations”, find the rules applying to games on n*n grid. 這是關於翻棋遊戲的可行解之探討。棋盤是一個4*4 的方格,遊戲開始時在棋盤上任意擺上一些棋子,均是正面朝上,利用相鄰棋子的水平、垂直、斜向跳躍,棋子被跳躍過一次則翻面一次,遊戲目的在於使所有的棋子都翻為反面。我要探討的是關於棋局可解不可解的問題,找出棋盤上可解棋局的規則。研究步驟大致如下:一、打破棋盤4*4 的限制,將棋盤座標化。二、找出若干個可解並可移動的「基本圖」。三、利用基本圖,找出n 列棋盤可解的規律。

Sub-Explorer

I came up with the idea to build a small submarine after researching the internet and discovering the problems in which divers had to face in dangerous and time consuming tasks. The Remotely Operated Vessel (ROV) was designed to perform hull inspections on boats to look for hull damage and leakage of contaminates such as oil or other chemicals into the water. Search, rescue and recovery, are also common tasks which need to be carried out by the police when searching for objects and items. The ROV has been constructed at a reasonably low cost for submersing in depths down to 10 metres. It is remotely operated therefore needing a tether cable to link up between the computer and the vessel. I built a computer case-top from parts that I already had to eliminate the need for an expensive laptop. A program that I wrote in QBASIC interprets input data from the operator and sends out signals to the various operations on the vessel such as to dive, surface, propel, etc. The entire project consisted of five individual technology processes. Key processes such as Propulsion, Maneuverability, Dive & Surface capability, Imaging system, and the Control system. Each process required a cost effective and practical solution but still needing to function efficiently and be low maintenance. Through continuous testing and trial & error I feel I came up with the best possible solutions with the limited amount of time and money I had to spend. I wouldn’t have got as far as I have without the help and support from friends, family and local businesses. They helped with ideas and advice from time to time, help with funding, and the sponsorship of materials and tools. Now that the ROV is complete, I have been able to trial and test it in a swimming pool. Apart from discovering a few minor leaks in the hull and ‘bugs’ in the computer program, I was able to witness the success of the vessel under operation and find any improvements that could be done to make it work better in future. With further more tests at greater depths the ROV will soon be at the stage where it can perform hull inspections of boats and find lost objects and items underwater. I feel it has the opportunity to be a marketable device to underwater industries all over the world.