Judul: Biodegradasi membran selulosa asetat berpori dari limbah kulit nanas menggunakan Bacillus subtillis
Abstrak: One alternative to solve difficult degradation of synthetic membrane is by using waste of pineapple peel to synthesize cellulose acetate (CA) membrane that is biodegradable. Examination of biodegradation was carried out by burying the membrane in soil for 5 weeks and by microbial degradation of membrane which weight had been known using Bacillus subtillis for 1, 2, 3, and 5 weeks. The degradation product were examined qualitatively using scanning electron microscope (SEM) before and after degradation. The weight of membrane after degradation by B. subtillis for 1, 2, 3, and 5 weeks were decreased 3.15, 20.06, 24.59, and 41.57%, respectively whereas with burying method in soil for 5 weeks the decrease was 50.15%. Fehling test of the CA membrane was negative before degradation and positive after degradation with increasing intensity every week. The SEM result of membrane before degradation showed that the membrane surface was relatively flat whereas the surface morphology of the one degraded by B. subtillis and of the one buried in soil changed and had broken and holes indicating that the membrane had been damaged.
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Judul: Kajian spektroskopi inframerah transformasi fourier dan mikroskop susunan elektron membran selulosa asetat dari limbah nanas
Abstrak: Pineapple production in Indonesia increases annually. Only 53% of pineapple can be consumed and the rest is thrown away. Pineapple peel can be converted into nata de pina to get a more valuable product. Next, nata de pina can be used as a raw material to produce membrane. This research begun with preparing nata de pina, purifying it to obtain the nata de pina powder. The powder were acetylated with acetic anhydride (1:5) for 2 h, to get cellulose acetate flakes. The membran was formed by dilluting cellulose acetate in dichloromethane solution and analyzed with Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM).
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Judul: Integration of Islamic Stock Markets of OIC Countries Before and During the Russia-Ukraine War Crisis
Abstrak: Pasar saham yang terintegrasi memberikan dampak negatif seperti percepatan co-movement (pergerakan bersama) yang rentan terhadap guncangan ekonomi, maupun krisis pasar global ke pasar domestik. Salah satu krisis yang terjadi pada tahun 2022 adalah perang Rusia-Ukraina yang berdampak pada pasar saham, termasuk pada saham syariah yang dipercaya lebih tahan terhadap guncangan krisis global. Penelitian ini bertujuan untuk meneliti perkembangan, integrasi dan respon lima pasar saham syariah negara OKI pada perang Rusia-Ukraina. Metode yang digunakan adalah VAR/VECM pada indeks DJIMMT25, SPSADS, SPSUAEDS, JII, DJIMT, SPBMIR, dan SPBMIU. Hasil penelitian menunjukkan pergerakan yang sama pada pasar saham UAE dan Arab Saudi, sedangkan Turki mengalami tren positif selama perang. Pasar saham syariah negara OKI selama periode perang Rusia-Ukraina terkointegrasi, sementara pasar saham Malaysia memengaruhi pasar saham syariah empat negara OKI lainnya. Hasil IRF menunjukkan terdapat efek permanen pada volatilitas pasar saham syariah negara OKI akibat guncangan yang diberikan. Namun, respon volatilitas relatif kecil karena kontribusi guncangan lebih didominasi oleh pasar saham itu sendiri, An integrated stock market has negative impacts, such as accelerating co-movement, which is vulnerable to economic shocks and global market crises on the domestic market. One of the crises in 2022 was the Russia-Ukraine war which impacted the stock market, including Sharia stocks which were believed to be more resistant to the shocks of the global crisis. This study examines the development, integration, and response of OIC countries five Islamic stock markets in the Russia-Ukraine war. The method used is VAR/VECM on the DJIMMT25, SPSADS, SPSUUAEDS, JII, DJIMT, SPBMIR, and SPBMIU indices. The results show the same movement in the UAE and Saudi Arabia stock markets, while Turkey experienced a positive trend during the war. The Islamic stock market of the OIC countries during the Russia-Ukraine war was cointegrated. In contrast, the Malaysian stock market influenced the Islamic stock markets of the other four OIC countries. The IRF results show a permanent effect on the volatility of the Islamic stock market in OKI countries due to the shocks given. However, the volatility response is relatively small because the stock market itself dominates the contribution of shocks.
Keyword: co-movement, OIC, Rusia-Ukraine war, sharia stock market integration