探討多子連線的最小阻隔數
2021年國際科展中,有作品探討鉛直與水平排列的支配數,而本研究從五子棋的想法出發,將前述研究進行重要的延伸與改變,探討在a×b棋盤中,「米」字方向無p子連線時,所需的阻隔數最小值。由於有界棋盤比無界棋盤複雜許多,因此我們先在無界棋盤中找出符合阻隔限制的「完美型態」,並找出存在至少一種「完美型態」的p值集合Ω。研究發現,只要是可以表示為p=6k-1或p=6k+1(k∈N)的正整數p,皆可以型態DT(p,d)阻隔。接著我們推廣至有界棋盤,先探討所有p值的f(a,b;p)上界與下界,再針對Ω中的p值做討論,利用「任意1×p區域至少有1個阻隔」的性質導出「完美型態」下長或寬為kp(k∈N)的下界,並找出非常接近f(a,b;p)的上界。我們也將二維的探討方式與結果延伸至三維,找出所有p值的f(a,b,c;p)上下界與可使阻隔型態DT(p,d_R,d_h)為完美型態的p值集合。另外我們也找出嚴格對角拉丁方陣可對應成「完美型態」之必要條件。
Utilization of Escherichia coli in Contiminated Water in the Citarum River as a Dual Chamber Baed On Microbial Fuel Cell (MFC) Substrat
Citarum River is the longest and largest river in West Java. The upstream of the Citarum River starts from Mount Wayang, Bandung Regency and ends at the mouth of the Java Sea which is located in Muara Gembong, Bekasi Regency. The Citarum River plays an important role as raw water for PDAM drinking water, supplies electricity in Java-Bali and provides water for rice field irrigation in West Java. Citarum watershed is dominated by the manufacturing industry sector such as chemicals, textiles, leather, paper, pharmaceuticals, metals, food and beverage products, and others. Based on data from the World Bank, every day, the Citarum River is polluted by approximately 20,000 tons of waste and 340,000 tons of waste water with the majority of the waste contributors coming from 2,000 textile industries. By looking at these events, there is no doubt that the sustainability of the ecosystem and the environment in the Citarum River is damaged and polluted. (Zahra Fani Robyanti; 2020). The West Java Regional Environmental Management Agency stated that the content of E. coli bacteria in the Citarum River had increased. The bacteria that cause diarrhea come from industrial and household waste. In addition to E. coli bacteria, other pollutants in the Citarum River that have increased are biological oxygen demand (BOD), chemical oxygen demand (COD) and Suspended Solids. One of the efforts that can be done regarding E. coli bacteria that pollute the Citarum river is to make it as a substrate for Microbial Fuel Cell (MFC). Bacteria present in organic media convert organic matter into electrical energy. The nature of bacteria that can degrade organic media (enrichment media) in MFC produces electron and proton ions. It is these ions that produce an electric potential difference so that energy can be generated. Generally in conventional systems, MFC consists of two chambers consisting of anode and cathode chambers. The two spaces are separated by a membrane where proton exchange occurs. This system has not fully worked with bacteria because only the anode side contains bacteria, while on the cathode side it still works using chemical compounds such as Polyaluminum Chloride (PAC). However, recently MFC has been developed using bacteria at the cathode, or better known as biocathode. Bacteria in the cathode space have the same function as electron mediators that were previously carried out by chemical compounds. In many studies on MFCs, acetate is commonly used as a substrate for bacteria to generate electricity. These chemical compounds are easier for bacteria to process than wastewater. Acetate is a simple chemical compound that serves as a carbon source for bacteria. Another advantage of acetate is that this compound does not cause other reactions to bacteria such as fermentation and methanogenesis at room temperature. Based on this thought, the author will design a study entitled Utilization of Escherichia coli Bacteria in Contaminated Water in the Citarum River as a Dual Chamber Based Microbial Fuel Cell (MFC) Substrate.