The choice of natural fibers as a composite reinforcing material is related to the advantages of being cheap, abundant, renewable, and environmentally friendly. This research was conducted to study the effect of de-lignification treatment on the properties of purun tikus (Eleocharis Dulcis) fiber. Purun tikus fiber has been modified with the alkaline treatment of KMnO4 2% and NaOH 5%. This treatment was mainly applied to improve the physical and chemical properties of purun tikus fiber. Changes in chemical characteristics (water, lignin, cellulose, and hemicellulose), physical (density), mechanical (tensile strength), morphology, and elemental content of purun tikus before and after treated with alkaline were studied. The measurements showed an increase in water content and density while lignin, cellulose, and hemicellulose were decreased. Thus the alkaline treatment of KMnO4 2% and NaOH 5% reduced lignin, cellulose, and hemicellulose of the purun tikus fiber to reduce the size of the fibers, as shown in SEM measurements. There was a change in elemental content after being treated with KMnO4 2% and NaOH 5%. NaOH treatment was better than KMnO4 treatment in terms of removing lignin and hemicellulose in purun tikus fiber. Although the tensile strength of the purun fibers treated with KMnO4 2% and NaOH 5% were lower than untreated, with less lignin, cellulose, and hemicellulose, it is expected that these fibers will blend better in the composite and improved its mechanical properties.

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

Characterization of wood waste from halaban wood, bottom ash, and coal fly ash has been done includes tests of water content, ash content, calorific value, and composition as well as morphology. One of the factors that influences the characteristics is the powder size. Therefore, this research uses 250 mesh sieve (smaller powder size) to make briquettes. From the test results, the average moisture content was 4.22% for halaban wood charcoal, 1.64% for bottom ash and 0.91% for fly ash. Average ash content of 41.93% for halaban wood charcoal, 82.03% for bottom ash and 89.69% for fly ash. Average Calorie Value of 6833.1 cal/g for halaban wood charcoal, 389.5 cal/g for bottom ash and for coal fly ash with calorie value of 0. From the SEM-EDX analysis results, there was no C mean of 76.69% In halaban wood charcoal, the average ash percentage of C was 41.87% and the average percentage of C was 16.17% in coal fly ash. The results of tests carried out are expected to be waste wood charcoal, basic ash and fly ash can be used as a mixture in the manufacture of briquettes.

<p class="abstrak">Calcium silicate ceramics have been made using natural ingredients such as rice husk and snail shell with solid reaction techniques. The aim of this study to determine the characteristics of calcium silicate that have been sintered at a temperature of 900 ^°C, 1000 ^°C, and 1100 ^°C. Samples were characterized by X-Ray Diffraction (XRD), optical microscopy, and Fourier Transform Infra-Red (FTIR). The results of XRD characterization showed that CaSiO₃ (calcium silicate) along with the increase in calcination temperature and quantity was increased due to the increase of temperature of calcination. FTIR analysis showed that the Ca-Si-O bond was formed at wave number ranging from 848 cm^-1 and 999 – 1001 cm^-1.</p>

Alat ukur kadar gas metana (CH4), suhu dan kelembaban telah dilakukan. Alat ukur ini dapat diaplikasikan di perkebunan kelapa sawit di lahan gambut. Alat ukur ini terdiri dari sensor TGS2611, sensor SHT11, catu daya, voltage follower, mikrokontroler ATMega8535 dan LCD karakter 16x2. Tegangan keluaran sensor TGS2611 dikondisikan dengan rangkaian voltage follower kemudian dihubungkan dengan ADC internal mikrokontroler ATMega8535. Persamaan karakteristik sensor TGS2611 ditentukan dengan cara mengambil beberapa data kadar gas metana dan tegangan keluaran sensor pada datasheet sensor TGS2611 kemudian dibuat grafik persamaan karakteristiknya, sehingga diperoleh persamaan karakteristik sensor V=0,544ln(x)-2,113, dengan V adalah tegangan keluaran sensor dan x adalah kadar gas metana (ppm). Sensor SHT11 merupakan sensor digital yang sudah terkalibrasi pabrik, sehingga sensor SHT11 bisa langsung dihubungkan dengan catu daya, lalu data dari sensor dihubungkan ke mikrokontroler ATMega8535. Data hasil pengukuran ditampilkan pada LCD karakter 16x2 dan ditampilkan pada komputer dengan program yang telah dibuat menggunakan Delphi 7.0. Data hasil pengukuran juga tersimpan dalam database. Hasil pengukuran yang dilakukan selama 2 hari dengan durasi pengukuran satu setengah jam pada hari pertama dan 2 jam pada hari kedua menyatakan bahwa keberadaan gas metana tidak terdeteksi di kebun kelapa sawit yang ditanam di lahan gambut. Pada hari pertama pengukuran nilai suhu udara berkisar antara 28,8 0C – 30 0C dan nilai kelembaban udara berkisar 87,6% - 89,6%. Pada hari kedua pengukuran nilai suhu udara berkisar antara 26,6 0C - 33,1 0C dan nilai kelembaban udara berkisar 85,1% - 88,4%.