Judul: Anti-termite Properties of the Extractive Substance of Magnolia sumatrana (Miq.)) Against Subterranean Termites (Coptotermes curvignathus Holmgren).
Abstrak: Manglid (Magnolia sumatrana Miq.) merupakan salah satu jenis tanaman yang banyak dikembangkan di hutan rakyat Jawa Barat. Jenis ini relatif cepat tumbuh dan termasuk kelas awet II, sehingga memiliki ketahanan alami terhadap organisme perusak kayu. Penelitian ini bertujuan untuk mengetahui kadar ekstraktif kulit kayu manglid serta mengukur bioaktivitas zat ekstraktif tersebut terhadap rayap Coptotermes curvignathus Holmgren dan menganalisis komponen senyawa kimia yang terkandung di dalam fraksi teraktif. Ekstrak aseton yang diperoleh melalui ekstraksi dengan metode maserasi, difraksinasi secara bertingkat dengan pelarut n-heksan, etil eter, etil asetat. Analisis kimia dilakukan terhadap fraksi yang paling aktif dengan alat GC-MS. Fraksi etil asetat memiliki persentase mortalitas rayap rata - rata tertinggi sebesar 55,47 % serta persentase kehilangan berat kertas selulosa rata - rata terendah sebesar 24,89 %. Senyawa yang diduga mengandung bioaktivitas anti-rayap, yaitu (+)spathulenol dan (-)- Caryophyllene oxide., Manglid (Magnolia sumatrana Miq.) is a plant that is widely developed in the community forests of West Java. This species is relatively fast growing and has durable class II, so it has natural resistance to wood destroyers. This study aims to determine the extractive content of the manglid bark and to measure the bioactivity of the extractive substance against the termite Coptotermes curvignathus Holmgren and to analyze the components of chemical compounds contained in the most active fraction. The acetone extract obtained by extraction by maceration method was fractionated in stages with n-hexane, ethyl ether, and ethyl acetate as solvents. Chemical analysis was carried out on the most active fraction by means of GC-MS. The ethyl acetate fraction had the highest average termite mortality percentage of 55.47% and the lowest percentage of cellulose paper weight loss was 24.89%. The compounds suspected to contain anti-termite bioactivity are (+)spathulenol and (-)- Caryophyllene oxide.
Keyword: Ekstrak aseton, Kulit kayu manglid (Magnolia sumatrana Miq.), Rayap tanah (Coptotermes curvignathus), Bioaktivitas anti-rayap, Mortalitas, Kehilangan berat, Acetone extract, Manglid bark (Magnolia sumatrana Miq.), Subterranean termites (Coptotermes curvignathus), Anti-termites’ properties, Mortality, Weight loss

Judul: Sifat Anti Rayap Zat Ekstraktif Kayu Manglid terhadap Serangan Rayap Tanah
Abstrak: Penelitian ini bertujuan untuk menentukan kadar zat ekstraktif kayu manglid, menganalisis sifat anti rayap zat ekstraktif kayu manglid terhadap rayap tanah, dan mengidentifikasi senyawa kimia teraktif pada zat ekstraktif kayu manglid. Serbuk kayu manglid diekstraksi menggunakan pelarut aseton. Ekstrak aseton selanjutnya dilakukan fraksinasi bertingkat dengan menggunakan fraksi nheksan, etil eter, dan etil asetat. Setiap fraksi dibuat konsentrasi 2, 4, 6, 8, dan 10% untuk pengujian sifat anti rayap, serta identifikasi senyawa kimia zat ekstraktif menggunakan GC-MS. Hasil penelitian menunjukkan bahwa kadar zat ekstraktif kayu manglid yang diperoleh sebesar 2.74%. Berdasarkan persentase mortalitas dan kehilangan berat, fraksi n-heksan memiliki aktivitas anti rayap tertinggi. Senyawa kimia dominan yang terdapat pada fraksi n-heksan berdasarkan analisis GC-MS yaitu β-Cyclodihydrocostunolide, bis (2-ethylhexyl) phthalate, eicosane, (+)-roemerine, tricosane, dan tetracosane.
Keyword: anti rayap, Coptotermes curvignathus, ekstrak aseton, fraksi nheksan, Manglietia glauca

Judul: Model Input-output dalam Masalah Network Flow
Abstrak: Production process is a process, which is done by industry, to transform input into output. According to the type of output and its activity, industry can be classified into various sectors, which are connected to each other. Therefore, a model to analyze the connection among sections is needed. The model is known as input-output model (IO model). IO model presents an IO table, which shows informations about the transaction between goods and services in each economic sector. Furthermore, the IO model also shows that the amount of all input is the same as the amount of all output. In this paper, the transaction of each economic sector in IO table is analyzed using network flow theory. The formulated network flow problem implies that each sector represents partly as a producer and also as a consumer. This paper also solves a minimum cost circulation problem.
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