Judul: Characteristics of Magnetic Wood Impregnated with Nano Iron (II, III) Oxide or Magnetite (Fe3O4)
Abstrak: Kayu sengon (Falcataria moluccana Miq.) dan kayu mangium (Acacia mangium Willd.) mempunyai kualitas yang inferior, sehingga diperlukan modifikasi kayu untuk memperluas pemanfaatan kayu cepat tumbuh ini, dengan menjadikannya kayu magnetik melalui impregnasi nano Fe. Penelitian ini bertujuan menganalisis karakteristik kayu magnetik hasil impregnasi nano Fe3O4 dan nano Fe3O4-FA serta menganalisis pengaruh impregnasi menggunakan nano Fe3O4 dan nano Fe3O4-FA terhadap kerapatan dan stabilias dimensi kayu. Larutan impregnasi terdiri dari tanpa perlakuan, 7,5% Fe3O4 serta 7,5%; 10%; 12,5% (Fe3O4-FA). Proses impregnasi dilakukan dengan diberi vakum 0,7 bar dan tekanan 3 bar selama 120 menit. Sampel diuji stabilitas dimensi dan kerapatan serta dikarakterisasi menggunakan Scanning Electron Microscope (SEM), Scanning Electron Microscope-Energy Dispersive X-Ray Spectroscopy (SEM-EDX), Fourier Transform Infrared Spectrometry (FTIR), X-ray Diffraction Analysis (XRD), dan Vibrating Sample Magnetometry (VSM). Hasil penelitian menunjukkan perlakuan Fe3O4 dan Fe3O4-FA berpengaruh nyata terhadap stabilitas dimensi dan kerapatan kayu sengon dan kayu mangium. Terdapat lapisan Fe pada dinding kayu dan menutupi noktah kayu (analisis SEM dan SEM-EDX) dan terdapat Fe-O (analisis FTIR) pada kayu sengon maupun kayu mangium terimpregnasi. Analisis XRD mendeteksi adanya senyawa magnetit terutama pada kayu yang diberi perlakuan. Berdasarkan analisis VSM, kayu sengon dan mangium magnetik memiliki sifat superparamagnetik dan dianggap soft magnet. Secara keseluruhan, perlakuan 10% Fe3O4-FA menghasilkan peningkatan stabilitas dimensi dan kerapatan kayu sengon dan mangium yang optimal., Sengon wood (Falcataria moluccana Miq.) and mangium wood (Acacia mangium Willd.) have inferior quality, so that would modification is needed expand the fast-growing wood, by making it magnetic through nano Fe impregnation. This study aims to analyze the characteristics of magnetic wood impregnated with nano Fe3O4 and nano Fe3O4-FA and to analyze the effect of impregnation using nano Fe3O4 and nano Fe3O4-FA on the density and dimensional stability of wood. The impregnation solution consisted of untreated, 7,5% Fe3O4 and 7,5%; 10%; 12,5% (Fe3O4-FA). The impregnation process was initiated by a vacuum of 0,7 bar and a pressure of 3 bar for 120 minutes. Samples were tested for dimensional stability and density and characterized using Scanning Electron Microscope (SEM), Scanning Electron Microscope-Energy Diffraction X-Ray Spectroscopy (SEM-EDX), Fourier Transform Infrared Spectrometry (FTIR), X-ray Diffraction Analysis (XRD), and Vibrating Sample Magnetometry (VSM). The results showed that the Fe3O4 and Fe3O4-FA treatments had a significant effect on the dimensional stability and density of impregnated sengon and mangium wood. The presence of Fe in the wood cell wall and covers the wood pits (SEM and SEM-EDX analysis) and there is Fe-O (FTIR analysis) on the impregnated sengon and mangium wood. XRD analysis detects the presence of magnetite compounds, especially in treated wood. Based on VSM analysis, magnetic sengon and mangium wood have superparamagnetic properties and considered as soft magnet. Overall, 10% Fe3O4-FA treatment resulted in the optimal increase in dimensional stability and density of sengon and mangium wood treated.
Keyword: dimensional stability, density, furfuryl alcohol, mangium, sengon

Judul: Sifat Fisis, Mekanis dan Karakterisasi Magnetik Kayu Sengon (Falcataria moluccana Miq.) Terimpregnasi Nano Magnetit (Fe3O4) Sintesis dan Komersial
Abstrak: Sengon merupakan kayu cepat tumbuh yang memiliki beberapa kelemahan. Dalam rangka meningkatkan kualitas kayu sengon, terdapat beberapa perlakuan yang dapat meningkatkan kualitas kayu, salah satunya dengan cara metode impregnasi menggunakan nano magnetit (Fe3O4). Penelitian ini bertujuan menganalisis pengaruh perlakuan impregnasi menggunakan partikel nano magnetit komersial dan sintesis terhadap sifat fisis dan mekanis kayu sengon hasil impregnasi dan mengkarakterisasi kayu sengon magnetik. Hasil pengujian menunjukkan bahwa kerapatan, weight percent gain, dan kekerasan kayu sengon hasil impregnasi nano magnetit sintesis dan komersial tidak berbeda nyata. Sedangkan perubahan warna kayu hasil impregnasi nano magnetit sintesis dan komersial menunjukkan perbedaan yang nyata. Hasil pengujian vector network analyzer menunjukkan bahwa kayu sengon yang diberi perlakuan nano magnetit sintesis 2,5% memiliki daya serap yang lebih tinggi dalam menyerap gelombang elektromagnetik dibanding dengan nano magnetit komersial., Sengon is a fast-growing wood which has several drawbacks. In improving the qualities of sengon wood, there are several treatments that can improve the quality of wood, one of which is the impregnation method using nano magnetite (Fe3O4). This study aimed to analyze the effect of impregnation treatment using commercial and synthetic magnetite nanoparticles on the physical and mechanical properties of impregnated sengon wood and to characterize magnetic sengon wood. The test results showed that the density, weight percent gain and hardness of sengon wood from synthetic and commercial nano magnetite impregnation were not significantly different. Meanwhile, the color change of wood from synthetic and commercial nano magnetite impregnation showed a significant difference. The results of the vector network analyzer test showed that treated sengon wood with 2,5% synthetic nano magnetite had a higher absorption capacity in absorbing electromagnetic waves than commercial nano magnetite.
Keyword: commercial, impregnation, nanoparticle, sengon, synthesis

Judul: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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