AbstrakSintesis nanokomposit Fe3O4@C dari bijih besi Tanah Laut dan sumber karbon dari gula pasir telah dilakukan dengan menggunakan metode kopresipitasi dan metode hidrotermal. Penelitian dilakukan untuk mengetahui karakteristik Fe3O4@C berbahan bijih besi. Sebanyak 6 g bijih besi digunakan sebagai bahan baku pembuatan Fe3O4. FeSO4.7H2O digunakan sebagai sumber ion Fe 2+ . Sampel diaduk dengan menggunakan temperatur 70 o C dengan kecepatan adukan 450 rpm. Karbon (C) disintesis menggunakan metode hidrotermal pada temperatur 300 o C dengan menambahkan etilon glikol sebagai surfaktan. Sampel Fe3O4 dan C digabung pada suhu 250 o C selama 30 menit dengan kecepatan 500 rpm. Sampel Nanokomposit Fe3O4@C dikarakterisasi menggunakan Vibrating Sample Magnetometer, Fourier Transform Infrared, Transmission Electron Microscopy, serta elektrokimia. Dari penelitian, diperoleh nilai magnetisasi saturasi sebesar 24,82 emu/g, jenis ikatan yang terdapat dalam nanokomposit Fe3O4@C adalah ikatan Fe-O, C=O, C=N dan O-H, distribusi ukuran partikel dalam rentang 5 nm -20 nm, dengan ratarata ukuran partikel 12 nm, serta nilai sensitivitas 0,285 mA/ppm. Kata kunci: bijih besi, karbon, nanokomposit Fe3O4@C

The structure, composition and water content of a oil palm wood influence its dynamic mechanical properties. These are very important to study in relation to wood applications. The quality of oil palm wood can be improved through formalization treatment in acid and alkaline conditions and then impregnated by melamine formaldehyde. Variation of formalization time and curing temperature after impregnation on specimens were investigated. Based on physical properties and FTIR characterizations, the formalization time of both acidic and alkaline conditions with the melamine formaldehyde impregnation treatment, showed improving in physical properties of the samples after treatment and this is also indicated with a shift in wave numbers and emergenced a new functional group on FTIR spectra of the samples. The curing temperature has also led to increase density and decrease water content of the specimen, so therefore revealing a decrease of the hygroscopicity of wood.

The landfills (TPA) Cahaya Kencana is applying system Sanitary Landfill, the landfill system that is done by the garbage dumped and compacted, then covered with dirt as cover and carried out continuously each end of the operation. This research is very important investigate the distribution of leachate contaminated leachate approximately systems Sanitary Landfill based on the resistivity value and the content of chemical elements in the holding pond. Based on the results of data processing 2D geoelectric Wenner configuration on four tracks with each track length of 100 m were processed using Res2dinv, obtainable at a depth of between 0.75 – 11.6 m resistivity values in the leachate is 4.34 – 10.0 Ωm track 2, 3, and 4, but are not on track 1. The results of laboratory test on four samples consecutive for content. BOD leachate from 26.2 - 121.0 mg/l; and COD 132.5 – 276.2 mg/l is not exceeded the limit of waste water quality standard, except for sample 4 with a COD value of 472.9 mg/l while for pH 7.24 - 7.39 mg/l and the concentration of heavy metals in leachate outlet still on the threshold of normal, where Pb <0.0019 mg/l; Cd <0.0019 mg/l; and Cr <0,0035mg/l.

Solar cell power monitoring software module in measurement of current and voltage has been made using data acquisition system device. This module is programmed by Delphi and designed according to the necessities for solar cell monitoring. Necessities for monitoring include many data that will be monitored, i.e: current, voltage, power, time and chart. This module will be integrated with hardware so that the data measured by the hardware can be acquired and displayed by the software module. All monitored data are also displayed through Microsoft Excel which then can be saved. Data acquired from the test are i.e: 0,05 A for current1, 0,2 A for current2, 0,027 V for voltage1, 0,15 V for voltage2, 0,001 W for power1, and 0,004 for power2.

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