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: Dimensional Stability and Magnetic Characterization of Sengon Wood Impregnated by Synthesized Magnetite Nanoparticles (Fe3O4)
Abstrak: Sengon merupakan salah satu jenis kayu cepat tumbuh, namun memiliki karakteristik yang inferior sehingga diperlukan modifikasi kayu untuk meningkatkan kualitas dan memperluas penggunaan kayu. Penelitian ini bertujuan untuk menganalisis pengaruh impregnasi nano magnetit hasil sintesis eksitu terhadap stabilitas dimensi dan kemagnetan kayu sengon magnetik dan mengkarakterisasi kayu sengon hasil impregnasi partikel nano magnetit (Fe3O4) dengan dispersan furfuryl alcohol (FA) dan air demineralisasi, serta menentukan perlakuan yang terbaik untuk meningkatkan kualitas kayu sengon. Sintesis nano magnetit diawali dengan pencampuran FeCl2 dan FeCl3 menggunakan prekursor NH4OH. Kemudian nano magnetit dicampurkan menggunakan dispersan menjadi larutan impregnasi dengan 8 perlakuan konsentrasi yaitu tanpa perlakuan, KM 7,5%, KM 10%, dan KM 12,5%, KFA, KMFA 7,5%, KMFA 10%, dan KMFA 12,5%. Proses impregnasi dilakukan dengan pemberian vakum 0,5 bar selama 30 menit dan tekan 1 bar selama 120 menit. Hasil penelitian menunjukkan bahwa perlakuan memberikan pengaruh yang nyata terhadap stabilitas dimensi kayu sengon hasil impregnasi. Keberadaan Fe yang terdeposit di dalam rongga dan dinding sel kayu terlihat pada analisis Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDX). Hasil analisis Fourier Transform Infrared Spectrometry (FTIR), menunjukkan adanya gugus fungsi Fe-O (magnetit). Analisis X-ray Diffraction Analysis (XRD) memperlihatkan penurunan persentase derajat kristalinitas dan adanya puncak khas magnetit. Hasil analisis Vibrating Sample Magnetometry (VSM) menyimpulkan bahwa kayu sengon magnetik memiliki sifat superparamagnetik dan digolongkan dalam jenis soft magnetic materials. Berdasarkan hasil pengujian, FA lebih cocok digunakan sebagai dispersan dengan konsentrasi 10% sebagai hasil yang terbaik untuk memperoleh kayu sengon magnetik dengan stabilitas dimensi dan magnetik yang baik., Sengon is one of the fast-growing woods, however it has inferior characteristics, thus requiring wood modification to enhance its quality and expand its utilization. This research aims to analyze the effect ex-situ synthesized magnetite nanoparticles impregnation on the dimensional stability and magnetic properties of magnetic sengon wood and to characterize impregnated sengon wood with magnetite nanoparticles (Fe3O4) using furfuryl alcohol (FA) and demineralized water as dispersant. The research also aims to determine the best treatment for enhancing the quality of sengon wood. The synthesis of magnetite nanoparticles begins with the mixing of FeCl2 and FeCl3 using NH4OH as a precursor. The magnetite nanoparticles is then mixed with dispersants to create an impregnation solution with 8 treatments, consisting of untreated, KM 7.5%, KM 10%, dan KM 12.5%, KFA, KMFA 7.5%, KMFA 10%, and KMFA 12.5%. The impregnation process involves applying a vacuum of 0.5 bar for 30 minutes and a pressure of 1 bar for 120 minutes. The results showed impregnation treatment had a significant effect on dimensional stability of treated sengon wood. The presence of deposited Fe within the wood cell walls and cavities are observed by Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDX) analysis. Fourier Transform Infrared Spectrometry (FTIR) analysis indicates the presence of Fe-O functional groups (magnetite). X-ray Diffraction (XRD) analysis reveals a degree of crystallinity decrease and the presence of distinct magnetite peaks. Based on Vibrating Sample Magnetometry (VSM) analysis, sengon magnetic wood has superparamagnetic properties and soft magnetic materials category. Based on the results, FA is more suitable as a dispersant at a 10% concentration as the best result for obtaining
Keyword: dimensional stability, dispersant, impregnation, magnetite nanoparticles, sengon

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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