Judul: Penentuan tarif optimal kendala individu rasional dan kesesuaian insentif pada perusahaan telekomunikasi
Abstrak: Ada dua perusahaan telekomunikasi yaitu perusahaan A dan perusahaan B. Masing-masing perusahaan memproduksi satu produk yang sama tetapi berbeda kualitas. Kualitas produk perusahaan B lebih baik dibandingkan kualitas produk perusahaan A sehingga harga produk perusahaan B lebih tinggi daripada harga produk perusahaan A. Pilihan konsumen untuk membeli produk pada suatu perusahaan hanya ditentukan oleh pendapatan konsumen dan harga produk perusahaan tersebut.
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Judul: Optimal Capital Structure, Investment Decision, Liquidity and Firm's Value in Telecommunication's Sector
Abstrak: Perusahaan mempunyai tujuan untuk meningkatkan nilai perusahaan karena semakin tinggi nilai perusahaan maka akan meningkatkan kemakmuran bagi para pemegang saham, sehingga para pemegang saham akan menginvestasikan modalnya kepada perusahaan tersebut. Nilai perusahaan merupakan persepsi investor terhadap tingkat keberhasilan perusahaan yang dikaitkan dengan harga saham karena harga pasar saham perusahaan mencerminkan penilaian investor atas keseluruhan ekuitas yang dimiliki. Semakin tinggi harga saham maka nilai perusahaan dan kemakmuran pemegang saham juga akan meningkat. Dalam penelitian ini faktor-faktor yang memengaruhi nilai perusahaan, struktur modal optimal dan variabel yang paling dominan dalam memengaruhi nilai perusahaan akan dipelajari. Populasi penelitian ini terdiri dari perusahaan telekomunikasi yang terdaftar di Bursa Efek Indonesia dalam periode 2009 hingga 2018. Hasil penelitian menunjukkan bahwa struktur modal dan keputusan investasi berpengaruh terhadap nilai perusahaan, sementara likuiditas, profitabilitas dan pertumbuhan perusahaan tidak berpengaruh terhadap nilai perusahaan. Selain itu penggunaan komposisi struktur modal optimal berada pada kisaran 20% utang jangka panjang dan 80% saham biasa untuk perusahaan TLKM. Pada perusahaan ISAT komposisi struktur modal optimal berada pada kisaran 28% saham biasa dan 72% saham preferen. Pada perusahaan EXCL komposisi struktur modal optimal berada pada kisaran 53% utang jangka panjang dan 47% saham preferen. Pada perusahaan FREN komposisi struktur modal optimal berada pada kisaran 28% utang jangka panjang dan 72% saham preferen. Sementara pada perusahaan BTEL komposisi struktur modal optimal berada pada kisaran 52% utang jangka panjang dan 48% saham preferen, agar menghasilkan biaya modal yang minimum serta nilai perusahaan yang maksimum. Untuk variabel yang paling dominan memengaruhi nilai perusahaan adalah struktur modal dan keputusan investasi dengan kriteria inelastis., The company has a goal to increase the firm’s value because the higher the value of the company will increase prosperity for shareholders, so the shareholders will invest their capital in the company. Firm’s value is the investor's perception of the level of success of the company that is associated with stock prices because the market price of the company's shares reflects the investor's assessment of the overall equity owned. The higher the stock price, the value of the company and the prosperity of shareholders will also increase. In this research the factors that influence firm value, optimal capital structure and the most dominant variables in influencing company value will be studied. The population of this study consists of telecommunications companies listed on the Indonesia Stock Exchange in the period 2009 to 2018. The results showed that capital structure and investment decisions affect the firm’s value, while liquidity, profitability and company growth do not affect the firm’s value. In addition, the optimal use of the capital structure composition is in the range of 20% long-term debt and 80% ordinary shares for TLKM companies. In ISAT company the optimal capital structure composition is in the range of 28% common shares and 72% preferred shares. In the EXCL company, the optimal capital structure composition is in the range of 53% long-term debt and 47% preferred stock. In FREN company, the optimal capital structure composition is in the range of 28% long-term debt and 72% preferred stock. Meanwhile, for BTEL, the optimal capital structure composition is in the range
Keyword: Struktur Modal Optimal, Keputusan Investasi, Likuiditas, Nilai Perusahaan, Capital Structure, Investment Decision, Liquidity, Optimal Capital Structure

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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