低雷諾數圓形及多邊形水躍的研究
打開水龍頭,水鉛直落到正下方的水平板時形成圓形水躍。我們實驗研究20<Nr<150 的低雷諾數圓形水躍的變因,探討圓形水躍半徑和流量、出水口高度、以及液體黏滯係數間的關係。改用高黏滯係數的液體(4:1 的乙二醇水溶液),鉛直落入板上方深h 的相同液體時,先形成圓形,h 漸大時形成環形圓紋曲面,再加大h,形成多邊形水躍,內外圍同方向旋轉,轉速ω;液中加水,黏滯係數高於及低於某定值,多邊形都消失,側面觀察,外圍液體作鉛直面旋轉。將水平板改置於旋轉盤上方,使高黏滯係數(4:1)的乙二醇水溶液鉛直落入板上方形成多邊水躍,逐漸加快旋轉盤的轉速至 ω 時,多邊形都消失;逐漸減少乙二醇的濃度,至完全用水實驗,亦有多邊形出現,我們認為;平板上方的液體的轉動是非圓形水躍的成因。When a jet of water falls vertically on to a horizontal plate, it spreads out rapidly in a thin layer until it reaches a critical radius at which the layer depth increases abruptly. This phenomenon commonly called the circular hydraulic jump. We study the variations of the circular hydraulic jump radius, as a function of volume flow rate of the jet, the drop height, and the viscosity of the fluid at low Reynold numbers (20<Nr<150). When a jet of ethylene-glycol mixed with water (the kinetic viscosity is 10 times of water) falls on to a horizontal plate which is immersed in the same liquid with height h. We find the circular state frequently undergoes spontaneous breaking at its axial symmetry into a stationary polygonal shape. Rather than displaying the weak angular deformation generally seen in fluids, the jump forms clear corners and edges that are often straight. Several of these polygon formations show consistency in height h. And we find the polygon structure rotates in a horizontal motion. When a jet of water falls on to a horizontal plate, and the plate is rotated by a motor ,we find the axial symmetry of the free surface of circular hydraulic jump is spontaneously broken a various number of cornered polygonal shapes. We study the number of corners as a result of the volume flow rate of the jet, the drop height and the viscosity of the fluid in the experiment. And the frequency of rotation of the plate is taking into consideration.
Secure safe
A documentary profile about an invention (a secure safe) Introduction: Firstly, we thank Allah, the Lord of all, and the Prophet Mohamed “peace be uponhim”. The importance of scientific innovations and inventions is demonstrated in the development of humanity fulfillment the requirements of modern life. In this respect, the presented innovation and thoughts have appeared in order to help the humanity. Within this context, the man or anyone needs to feel secure as far as his wealth and properties are concerned. Within this regards, the idea of creating (inventing) a secure safe appeared, and this will enhance the perspective of security, and confidence via making a secure safe. It has been stated in our Scared Quran “co-operate and help each other in the constructive and good works and don’t co-operate to do hostility and bad actions. Invention identity: Name of the invention: secure safe Components: sensor, mobile phone, battery, conductive means (wires)How does the invention work? Operating Process Firstly, when approaching or touching the safe body, the electric circuit attached to a sensor in the safe is closed and this will directly get the mobile phone ring. Therefore, the safe’s owner will realize that there is danger about his properties or the money included in the safe. The main objective of the invention: Adding further security to the private and public properties, and enabling the owner to watch or control his properties all time everywhere. Where this invention can be used: usage fields This invention will be used in the security domain as well as that of the economic. It can be employed and used instead of a lot of security persons. The future vision of the invention Its components can be integrated into one unit and therefore the usual size can be minimized. Further, it could be possible to add a camera to the invention to be used for additional purposes in several fields; e.g. cars, premises, house, etc.
A Coin Sorting Box
This project aimed to create a simple model of coin sorter with cheaper price, electricity saving using recycled materials for use in place of manual separation and compatible to the automatic coin sorters commercially available in the market. The principle applied in inventing this device was the gravity force that pushed coins to fall through its upper compartment to the lower part via a slope that determines the coin path as well as the speed of the coins. The upper part of the box was designed to control the rate of the descending coins and transported the coins to the separation section in single file order to prevent jamming. The lower part of the box consisted of the coin sorting mechanism which conveyed the coins to their assigned compartment according to coin diameters. The box could separate three kinds of Thai coins, 1,5 and 10 baht, with 95-98 % accuracy. The efficiency was in the range 150-250 coins per minute with highest accuracy at 150 coins per minute. The box was made from acrylics. The designed box can separate coins faster than manual sorting although not with as high efficiency as automatic machines which can sort up to 500 coins per minutes. At the present stage, it can not count the number of coins. However, it can be built at cheaper cost, does not require electricity or electronic devices and is suitable for small and medium size business. We aim to improve the box to give higher accuracy with coin counting ability.
仿生智慧型熱控制系統
通常使用隔熱材料可以降低熱量傳遞,而使用風扇、散熱片、熱導管等用來單向散熱。但如何在一個系統上同時滿足隔熱和雙向傳熱的需求呢?因此我研究設計了仿生智慧型熱控制系統,能隨環境改變而快速轉變成隔熱或轉變成雙向傳熱並控制熱傳遞的方向及大小,這可以應用在房屋、汽車、恆溫系統等。我先自製了自動傳熱量測系統,測試並找出好的隔熱和傳熱材料及構造。為了能快速控制熱的方向及大小,我又發展了第一代替換式、第二代熱柵式和第三代熱管式熱控制系統;經過多次實驗,利用低沸點有機溶劑和控制系統,我成功地完成仿生智慧型熱控制系統,讓熱隔絕或快速流進流出,比傳統的方法改進很多,也達到節約能源的目的。Insulation materials are usually used to reduce heat transfer rate, while fans, radiators and heat pipes are applied to increase heat transfer rate and bring heat away. But is it possible to have both functions of insulation and heat transfer together in a single system? This research is to design and develop an intelligent heat control system, with both function of insulation and function of transferring heat together. Besides, this system can control the direction and amount of heat transferred. Such a system can be applied in house walls, cars, thermostatic system, etc. I developed an automatic heat measurement system which was used to test the properties of heat transfer for different materials and structures. Three generations of intelligent bi-directional automatic heat control system were then developed to get fast heat transfer and function of heat control. They were phase 1 replacing-type system, phase 2 heat-grating system, and phase 3 heat-pipe system. After tens of experiments, I successfully control the amount and rate of heat transfer via low-boiling-point organic solutions and controller. The designed system is bi-directional, and is more innovative and efficient than conventional uni-directional heat control methods. Besides, this system also has huge contribution in reducing energy consumption.
M&m Sequences 之研究
本專題的目的是研究以任意實數 a1 、 a2 、 a3 為起始的M&m Sequences 之穩定性質。我們主要關心的問題是:(1) 是否任給定三數a1 、 a2 、 a3 為起始的M&m 數列皆會穩定?(2) 若上述的M&m 數列穩定,則其穩定的長度與a1 、 a2 、 a3的關係為何?(3) 其穩定的值與a1 、 a2 、 a3的關係為何?我們研究的主要步驟及結果如下︰1. 當1 2 3 a 1) 為起始的M&m 數列。3. 我們證明了下列性質:(1) 若M&m 數列中前n 項所成數列的中位數為n m ,則下式成立: (2) 當存在 k > 4 , k ? N ,使得 ?1 ?2 = k k m m 成立時,則此數列穩定,且穩定長度p 滿足:min{ | 4 } ?1 ?2 = > = k k p k k 且m m ,其中p 必為奇數。(3) { n m }為單調遞增且, 5 1 ? ? ? a m n n n4. 如果x ? 41.625,則{?x,1, x}為起始的M&m 數列,其對應的數列有相同的大小次序且此M&m 數列會穩定,穩定值為41.625,且穩定長度為73。5. 我們觀察發現:如果x 1). 3. We prove the following properties: (1) If the median of the former n numbers of the M&m sequence is n m , we obtain (2) There exist k > 4 , k ? N such that ?1 ?2 = k k m m , then the sequence is stable and the stable length min{ | 4 }?1 ?2 = > = k k p k k and m m , where p must be an odd number. (3) { n m } is monotone increasing and , 5 1 ? ? ? a m n n n . 4. Suppose x ? 41.625, then the all M&m Sequences beginning with –x , 1 , x are the same, and the sequences will be stable, the stable value is 41.625 and the stable length is 73. 5. By the computer experiments, we observe that if x is any positive real number less than 41.625, the M&m Sequence starting with –x, 1, x, will be also stable but does not appear to follow any clearly discernible pattern of behavior. However, the stable lengths are much variant and exist some unknown relation with point format of x. Moreover, we have the following properties: (1)If x is a node, then the stable value is x and the stable length equals to the index of median of the node + 2; (2)Near the branch of 41.625, the stable length is almost a constant except at the edge area,the stable length of (-x,1,x) as x around branch 1 is chaos; (3)If x near the node (K= 3, 5, 7, …, 67, 69), then the stable length is l(K)+K?1 where the positive integral l(K) is determined by Prop1 (see Table 6 and 7).
Green tea causes preventing cancer
Now a days cancer is one of the most important factor of death in the world so we decided to introduce people one of the easiest way of it’s prevention. However, the relation between green tea and cancer is not completely identified but the research shows that drinking green tea reduce the state of cancer. First we found some information about the green tea compounds then we investigated the cancer factors in different countries and stidied the experiments among 900 women showed that drinking tea reduce the state of ovary cancer. Green tea contains A, B, C, D vitamins & Fe, folic acid &also minerals such as Ca, K, Zn. This useful soft drink is a strong Anti?oxidant so prevent any kinds of cancer & blood clot. Therefore it reduce the state of heart attack. (Up to 31%) So it is not only prevention factor but also it can open a new way to cure different cancers.
滑鼠狂想曲
光學滑鼠會以很高的速度不斷地對著接觸面拍照,藉由比對每幅影像間的變化來偵測滑鼠移動的速度與方向,本研究利用此特點而設計一個簡易的光學量測系統,其中包括透鏡、光源與接觸面材質的選擇,以及利用Raw Input 模式讀取個別滑鼠移動訊息而發展出來的量測程式,使得此系統可以在無接觸與無摩擦的情況下來測量外界物體的移動速度與距離,經由實驗證明,在光學感測器還可以感應與追蹤的範圍內,量測的數據還蠻精準的。接觸面到光學感測器透鏡的距離越遠,能夠測得移動物體的極速也越高,但是會造成感測器的解析度下降,如此限制了接觸面的材質種類,無法量測表面較為光滑的物體,但是在設計得宜的情況下,仍有蠻多方面的用途,日後若能採用較高效能的光學感測器並加上測距儀的輔助,相信此系統的應用層面會更為廣泛。Optical mouse can take continuous snapshots very quickly of the contact surface and compare the images sequentially to detect the direction and amount of movement. This study uses this feature to design a simple optical measurement system, including lens, illumination and contact surface choice, as well as the measurement program using raw input model to accept the movement information from the mouse. This system can measure the distance and speed of the motion object under the non-friction condition. From the experiment test result, this optical measurement system is workable and satisfactory. Contact surface to optical sensor distance farther, can measure the higher speed of the motion object, but will cause the lower resolution of the optical sensor. This will limit the variety of the contact surface; superficial smoother object is unable to measure. In the future if we can use the high performance optical sensor and assist with rangefinder, believed this system can have more widespread applications.