Construction of an Emergency Portable Dynamo Mobile Phone Charging Station by Means of a Hand-Crank Gear Mechanism/ Solar Panels
The researchers aim to construct an emergency mobile phone charging station that runs on renewable energy and will serve as a cost-efficient alternative to more traditional power banks. Circuit components include a 20V / 6W solar panel supplemented by a hand-crank gear mechanism integrated with a 6V / 1A lead-acid battery, a usb output and an adjustable switch-mode power supply (SMPS) to convert excess voltage into current. Initial voltage and current outputs were measured under varying resistances. It was determined that the set-up satisfied the minimum voltage and current requirement for charging a mobile phone (5V / 1A). A subsequent phone charging test was executed using a Samsung Galaxy J2 (3.85V Li-ion battery 7.70W, Charge Voltage: 4.4V / 2000mAh) wherein it charged on an average of 0.277% per minute for the solar panel and an average of 0.263% per minute for the hand crank gear mechanism. A Mann-Whitney U statistical test was conducted to determine if the charging rate of the charging station had a significant difference from a commercially available power bank’s. The calculated UA: (4) from the test was below the lower limit and the UB: (217) was above the upper limit which indicated that there was a significant difference between the charging rates. While the efficiency was lower than the commercial power bank’s, it can still be used as an alternative charging method especially during emergencies and disasters.
三角形與其外接錐線的生成錐線性質探討
本研究源自三角形的重心及其外接圓所構作的線段比值的古老幾何性質,我們不但推廣原命題,還創造新命題:給定△ABC與其外接錐線Γ,令直線AG, BG, CG分別交Γ 於 A', B', C' 點,再取任意k值,探討P點集合的性質。 Γ3, k={P|AA'/PA' + BB'/PB' +CC'/PC'=k} (1)Γ3,k為二次曲線系,其橢圓、拋物線、雙曲線之形態不因k值而改變,而是被外接錐線Γ所決定。 (2)發現△ABC重心 G、Γ中心O、Γ3,k 中心O3,k 的共線性及比例常數。 (3)完整劃分 Γ3,k的非退化與退化型態,並發現只有Γ3,k 為橢圓時,k 值有跳躍現象。 (4) 發現錐線Γ上取相異六點而生成兩個錐線Γ3,k、Π3,k重合的充分條件。 最後,我們以「錐線 Γ 上取一點、兩點到多點」的線性組合手法,推廣多邊形與其外接錐線的生成錐線Γn,k之性質。
Application of molecular templates on magnetic particles for adsorption and desorption of heavy metals
This study investigated the production of novel molecular templates, and analyze their adsorption effect on four heavy metal ions (Cu+2, Pb+2, Zn+2, Mn+2), which commonly exist in Taiwan's rivers. Different operating conditions (such as competitive adsorption, pH value and other factors) were explored to compare their adsorption effect of heavy metal ions by using the synthesized template molecules. The molecular templates were found to be specific towards their target metal ions with a high adsorption effect. Then combined with the idea of magnetic particles to produce magnetic molecule templates, a maximum amount of adsorption of heavy metal ions up to 95% through the molecular template was achieved while the effect of heavy metals desorption of up to 83% could be also successfully obtained. Experimental results showed that the magnetic molecule templates did not affect the adsorption of heavy metal ions. Not only can they speed up the recovery time of adsorption but the template molecules can also be collected more efficiently. We also proposed three different applications for the developed molecular templates. The development of magnetic molecular template may provide an affordable, highly-efficient way for dealing with heavy metal pollutions.