全國中小學科展

2013年

The gyroscopic effect of bicycle wheels

The aim was to determine whether there is an amount of gyroscopic force that keeps a bicycle wheel upright and stable. Two hypotheses were used, the first being as the mass of a wheel increases so does the force required to tilt the wheel by thirty degrees and the second that as the speed at which the wheel is spun increases so does the force required to tilt the wheel.

Fabrication and Characterization of Dye-Sensitized Solar Cells Using Bixa orellana Seeds and Basella alba Leaves

Dye-sensitized solar cells (DSSCs) have cheaper and easier means of fabrication compared to the currently used solar cells, which are mostly silicon-based, so DSSCs are developed for a prospect of solar energy accounting for a higher percentage in the world’s total energy production, which is currently 0.1%. However, compared to their inorganic counterparts, their efficiencies are low, and the search for a dye that will maximize the potential of DSSCs is still ongoing. The aim of this study is to be able to evaluate the absorption range in the solar spectrum of dyes extracted from Basella alba leaves and Bixin orellana seeds, and of dyes resulting from the mixture of both extracts, using UV-Vis Spectrophotometer, with the objective of increasing the absorption; to be able to fabricate functional DSSCs from the individual and mixed dyes; and to be able to evaluate the different conversion efficiencies of the DSSCs of the individual and mixed dyes using Linear Sweep Voltammetry, with the aim of increasing the conversion efficiency due to a wider absorption range. B. alba leaves and B. orellana seeds were extracted using soxhlet extraction. The clean extracts were mixed in different proportions, and were characterized using UV-Vis Spectrophotometer. The two individual dyes together with two proportions of the mixed B. alba:B. orellana dyes, 1:1 and 2:1, were then incorporated into DSSCs. In the fabrication of DSSCs, twelve plates of Fluorine doped tin oxide were coated with titanium dioxide (TiO2) using spray pyrolysis. They were sintered and scraped, and were afterwards immersed in the four dyes for four days. Platinum plates were placed on top, and iodine-triiodide couple electrolyte was introduced via capillary action. The sealed DSSCs were subjected to Linear Sweep Voltammetry under dark and illuminated conditions, using a sun simulator. Results from the UV-Vis spectrophotometry showed that mixing the dyes had increased the absorption range of the individual dyes, although not superpositionally, and that the 2:1 mixed dye has the most potential. Being incorporated into DSSCs, the dyes, including the mixed ones, have successfully converted solar energy into electrical energy, as shown by the significance in conversion efficiencies under dark and illuminated conditions. However, despite the increase in the absorption range, neither of the mixed dyes have shown a higher conversion efficiency than the individual ones, which can be accounted for a possible weaker interaction between the two dyes and the TiO2, resulting to lower efficiencies. The study has been able to obtain and characterize dyes from B. orellana seeds and B. alba leaves and has been able to incorporate the dyes into DSSCs. With the wider absorption range of the mixed dyes, the study has been able to confirm the possibility of the dyes to maximize the potential of DSSCs, as shown by the successful conversion of solar energy into electrical energy of all fabricated DSSCs, including those of mixed dyes. If the possible problem with the dye-dye as well as the dye-TiO2 interactions could be solved, the possibility of much higher conversion efficiencies could be expected.

Carbon Nanostructures Via Dry Fce Exposed to High Temperature

This science project is designed to answer a question of whether or not a chemical reaction is needed to produce industrial quantities of carbon nanostructures by exposing dry ice to a high temperature that is at least 3100°C. A small carbon arc furnace powered by an electric welder is used to produce the high temperature. During control runs, the carbon arc furnace is energized for a predetermined time, after which the carbon arc furnace is de-energized and any carbon particles within the furnace are collected. During carbon nanostructures synthesis runs, dry ice is placed within the carbon arc furnace. The carbon arc furnace is energized and the dry ice is consumed for the predetermined time. Carbon nanostructures synthesized during the synthesis runs are collected once the carbon arc furnace is de-energized and allowed to cool. The volume of the carbon particles collected during the control runs is compared to the volume of the carbon nanostructures produced by the synthesis runs. This science project has discovered that on average at least 16 times more carbon nanostructures are produced during synthesis runs consuming dry ice as opposed to the control runs. Moreover, the synthesis runs did not rely on chemical reactions. Further still, samples of the synthesized carbon nanostructures were imaged using a transmission electron microscope (TEM). The TEM images clearly show high-quality carbon nanostructures that include carbon nanotubes, faceted carbon nanospheres, and the super-material graphene.

Chitosan Defies Death

Gangrene is the death of tissue of certain parts of the body. In Indonesia, people who suffer from Diabetes will also often suffer from Gangrene, which usually affects a patient’s feet. The medication for it is not affordable for everybody. I have chosen the Horseshoe Crab, simply because it’s known widely in Indonesian and can be found easily. Also, due to the fact that, among all crustaceans, the Horseshoe Crab contains the highest levels of Chitin. By using the Chitin found in the shell of the Horseshoe Crab, I shall endeavor to heal the Gangrene of Diabetic Patients.

Synthesis and Analysis of New BiS2-based Layered Superconductor

本研究主要探討傾角對面轉變的影響與面轉變的原因。當柱體由肥皂水中拉起時,泡膜圖形可分為中央膜平行與垂直底面的形式,兩種形式因高的變化而互相轉換的過程稱為面轉變。三到六角柱傾角越大,面轉變時的高越大,反之亦然;六角柱可以面轉變,且在40°到45°之間有臨界角度存在。本研究以力與能量的角度解釋面轉變.泡膜藉由改變面積以達到最低的能量、維持穩定狀態,因此本研究計算、比較不同形式的泡膜面積,以解釋面轉變。我們同時發現三角錐與四角錐都不會發生面轉換;三角錐的實驗值多大於理論值,四角錐的實驗值則多小於理論值。

Saccharomyces cerevisiae 單倍體親代的RLS年齡對有性生殖後二倍體子代的影響

Saccharomyces cerevisiae 藉由出芽生殖的方式產生子代,而執行的次數並非無所限制。酵母菌一生的分裂次數(壽命)稱為 Replicative Life Span ( RLS ),指的是母細胞在停止分裂前所產生的子代數目。本實驗將老單倍體細胞( RLS 中位數: 6代 )和年輕單倍體細胞( RLS 中位數: 20代 )透過有性生殖的方式形成合子,發現合子的 RLS ( 中位數: 10.5代 )會受到老細胞的影響而縮短,並且接近兩單倍體親代 RLS 中位數的算術平均數( 13代 ),而其 F1 子代的 RLS 卻能回復與雙倍體相似的壽命。發現單倍體親代老化導致合子短命,可進一步推測人類生殖細胞老化對受精卵的影響模式。 

以直向、橫向、斜向磁磚鋪滿mxn矩形的研究

我們的主題是研究使用直向、橫向與斜向磁磚不交疊地鋪滿m × n的長方形的方法總數。磁磚總共有如圖A中間所列出的四種(其中著上藍色和綠色兩者統稱為「斜向的」磁磚),並且斜向磁磚不能夠有圖所顯示的交疊的情形。在1961 年的論文中給出了只使用直向、橫向磁磚鋪滿2m × 2n 的長方形的方法數的一個漂亮的公式,而2001 年的論文以一個較簡單的方法證明了這個結果。(1)(2)(3) 而我們先從固定 m 尋找遞迴式的方法出發,接著用m 的結果推出m + 1,最後期望能找出與論文一樣的一個漂亮的一般通式。