Judul: Proof of the J-Curve Phenomenon and Analysis of Exchange Rate Asymetry of Indonesia with Her Main Export Countries
Abstrak: Depresiasi nilai tukar berpengaruh dalam menimbulkan defisit pada neraca perdagangan. Namun, menurut teori J-Curve, depresiasi nilai tukar dapat memperbaiki neraca perdagangan pada jangka panjang. Studi empiris mengenai pembuktian fenomena J-Curve telah banyak dilakukan dengan hasil yang bervariasi. Variasi tersebut disebabkan penggunaan data agregat dan disagregat serta tidak memperhitungkan pengaruh asimetris dari pergerakan nilai tukar. Penelitian ini bertujuan untuk membuktikan fenomena J-Curve dengan mempertimbangkan hubungan asimetris jangka pendek dan panjang dari nilai tukar rupiah terhadap neraca perdagangan Indonesia dengan sepuluh negara mitra utamanya pada periode Januari 2016 – Desember 2021. Hasil penelitian ini membuktikan bahwa dengan menggunakan model NARDL (Nonlinear Autoregressive Distributed Lag), enam dari sepuluh negara mitra Indonesia (China, Amerika, India, Jepang, Taiwan, dan Thailand) terbukti terdapat efek asimetris jangka panjang. Sementara itu, terdapat efek asimetris jangka pendek pada lima negara mitra Indonesia (China, Filipina, Korea Selatan, Taiwan, dan Thailand). Fenomena J-Curve terbukti terdapat pada Taiwan dan Thailand., Basically, the depreciation of the exchange rate has an impact on creating a trade balance deficit. However, according to the J-Curve theory, exchange rate depreciation can improve the trade balance in the long-term. Empirical studies regarding the proof of the J-Curve phenomenon have been carried out with varying results. The variation of the result is due to the use of aggregated and disaggregated data also they did not include the asymmetric effect of exchange rate movements. This study aims to prove the J-Curve phenomenon by considering the short- and long-term asymmetrical relationships of the rupiah exchange rate on Indonesia’s trade balance with her ten main partner countries within the period of January 2016 – December 2021. The result of this study proves that by using the NARDL (Nonlinear Autoregressive Distributed Lag) model, six out of ten of Indonesia’s partner countries (China, America, India, Japan, Taiwan, and Thailand) have proven to have long-term asymmetric effects. Meanwhile, there are a short-term asymmetric effect in five ten of Indonesia’s partner countries (China, Philippines, South Korea, Taiwan, and Thailand). In addition, the J-Curve phenomenon is founded in two of Indonesia’s partner countries which are Taiwan and Thailand.
Keyword: Asymetry Effects, J-Curve, NARDL, Partner Countries of Indonesia

Judul: Analisis Pengaruh Nilai Tukar Riil Terhadap Neraca Perdagangan Bilateral Indonesia Dengan Tiga Mitra Dagang: Fenomena J- Curve
Abstrak: Penelitian ini bertujuan untuk menganalisis pengaruh nilai tukar riil (Real Exchange Rate/RER) terhadap neraca perdagangan bilateral Indonesia dengan tiga mitra dagang utamanya, yaitu: Amerika Serikat, Cina, dan Jepang, baik dalam jangka pendek maupun jangka panjang. Penelitian ini juga menginvestigasi terpenuhinya kondisi Marshall-Lerner dan keberadaan fenomena kurva-J pada neraca perdagangan bilateral Indonesia antara 1996:Q1 hingga 2011:Q4 dengan menggunakan metode Vector Error Correction Model (VECM). Penelitian ini mengindikasikan bahwa (i) dalam jangka panjang, RER memiliki pengaruh negatif terhadap neraca perdagangan bilateral dengan Amerika Serikat dan pengaruh positif terhadap neraca perdagangan bilateral Indonesia dengan China dan Jepang. (ii) Dalam jangka pendek, RER tidak memiliki pengaruh terhadap neraca perdagangan bilateral Indonesia dengan Amerika Serikat dan memiliki pengaruh positif terhadap neraca perdagangan bilateral Indonesia dengan China dan Jepang. (iii) kondisi Marshall-Lerner dan fenomena kurva-J hanya terlihat pada neraca perdagangan bilateral Indonesia dengan China dan Jepang.
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Judul: Synthesis of Apatite - Chitosan Composite Using Duck Eggshell and Chitosan with Temperature and pH Control
Abstrak: Composite of apatite-chitosan was prepared by using chitosan as polymer matrix. Calcium phosphate was prepared from CaO and (NH4)2HPO4, which the ratio Ca : P had to be 1.67. Chitosan is produced by deacetilase from biopolymer chitin. Duck eggshell (95% CaCO3) as starting material was converted to be calcium oxide (CaO) through calcinations with temperature 1000oC for 5 hours. In-situ and ex-situ methods were prepared from apatite and chitosan (dissolved with acetate acid 2%). Calcium phosphate prepared for bone implantation, but it is too fragile and brittle to be implant into the body. So addition of chitosan can decrease crystalinity and increase mechanic characteristic (tougher). Composite apatite-chitosan was resulted by fast precipitation. Fast precipitation was held in a breaker glass with nitrogen atmosphere, under controlled temperature at 37oC and pH 7, in order to increase amount of hydroxyapatite. Precipitation with CaO which was dropped by (NH4)2HPO4. Hydroxyapatite and chitosan were appearing at samples with in-situ and ex-situ methods which indicating by peak matching of XRD (closed lattice parameter, crystal size), overlapping at FTIR spectra and supporting by SEM picture (homogenous and agglomerated particle). However, it still needs further research to examine biocompatibility osteoconductive degree of sample by in-vivo and in-vitro test.
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