Judul: The Effect of Asymmetric Rupiah Exchange Rate on Export of Indonesian Agricultural Sector
Abstrak: Indonesia menganut sistem nilai tukar mengambang bebas dengan sistem nilai tukar tergantung mekanisme permintaan dan penawaran mata uang di pasar valuta asing. Namun sistem ini memiliki kelemahan yaitu nilai tukar mudah mengalami depresiasi dan apresiasi sehingga pergerakan nilai tukar cenderung memiliki tren fluktuasi. Nilai tukar menjadi hal menarik untuk diteliti karena pengaruhnya terhadap perekonomian suatu negara, salah satunya adalah ekspor sektor pertanian. Pergerakan ekspor mengikuti pergerakan nilai tukar. Sedangkan sistem mekanisme transaksi ekspor sektor pertanian Indonesia menggunakan sistem kontrak, sehingga menyebabkan pergerakan ekspor tidak mengikuti pergerakan nilai tukar jika dibandingkan dari bulan ke bulan. Berdasarkan hal terebut, maka mengindikasikan bahwa terdapat efek asimetris nilai tukar rupiah terhadap ekspor sektor pertanian Indonesia. Namun pada penelitian terdahulu umumnya mengabaikan adanya efek asimetris nilai tukar rupiah terhadap ekspor yang mungkin saja dapat terjadi. Oleh karena itu, penelitian bertujuan: (1) Menganalisis pengaruh asimetris nilai tukar rupiah terhadap ekspor sektor pertanian Indonesia. (2) Menganalisis perbedaan perubahan ekspor sektor pertanian Indonesia yang dipengaruhi oleh efek apresiasi dan efek depresiasi rupiah. Data penelitian berjenis data sekunder. Periode data menggunakan data bulanan selama 169 bulan (Januari 2006 sampai Januari 2020). Metode penelitian yang digunakan adalah Nonlinier Autoregressive Distributed Lag (NARDL), untuk menganalisis efek asimetris yang mungkin dimiliki nilai tukar rupiah terhadap ekspor sektor pertanian Indonesia. Hasil penelitian menunjukkan bahwa: (1) Terdapat efek asimetris nilai tukar rupiah terhadap ekspor sektor pertanian Indonesia pada jangka pendek dan jangka panjang. (2) Perubahan ekspor sektor pertanian merespon positif ketika efek apresiasi pada lag 1 dan efek depresiasi pada lag 2 pada estimasi jangka pendek. Pada hasil estimasi jangka panjang, perubahan ekspor sektor pertanian memiliki efek negatif ketika apresiasi dan depresiasi rupiah. Perubahan ekspor sektor pertanian lebih besar dipengaruhi efek depresiasi dibandingkan efek apresiasi. Kata kunci: asimetris, ekspor pertanian Indonesia, NARDL, nilai tukar rupiah, Indonesia adheres to a free-floating exchange rate system with an exchange rate system, depending on the demand and supply mechanism for currency in the foreign exchange market. However, this system has a weakness, namely the exchange rate is easy to depreciate and appreciate so that exchange rate movements tend to have a fluctuating trend. The exchange rate is an interesting thing to study because of its influence on the country's economy, one of which is the export of the agricultural sector. Export movements follow exchange rate movements. Meanwhile, the export transaction mechanism system for the Indonesian agricultural sector uses a contract system, so that export movements do not follow exchange rate movements when compared from month to month. Based on this, it shows that there is an asymmetric effect of the rupiah exchange rate on exports of the Indonesian agricultural sector. However, previous research generally ignores the asymmetric effect of the rupiah exchange rate on the possibility of exports. Therefore, the research aims: (1) Analyze the asymmetric effect of the rupiah exchange rate on exports of the Indonesian agricultural sector. (2) Analyzing the differences in changes in exports of the Indonesian agricultural sector which are influenced by the effect of appreciation and the effect of depreciation of the rupiah. The research data are secondary data. The data period uses monthly data
Keyword: agricultural export Indonesian, asymmetric, NARDL, Rupiah exchange rate, agricultural export Indonesian, asymmetric, NARDL, Rupiah exchange rate

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: Hydrothermal Synthesis of Biphasic Calcium Posphate
Abstrak: Biphasio calsium phosphate (BCP), which was a mixture of hydroxypatite (HA) and tricalcium phosphate (TCP), was synthesized by hydrothermal method followed by sintering process. Hydroxyapatite was produced by using natural calcium source CaO from hen's eggshell and (NH4)2HPO4 as phosphate souce, other hydroxyapatite sample was produce by using synthetic calcium source Ca(OH) and H3PO4 as phosphate source.
Keyword: