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STUDI PENGARUH KONSENTRASI AL PADA STRUKTUR KRISTAL DAN MORFOLOGI FILM TIPIS AlxGa1-xN/Si(111) YANG DITUMBUHKAN DENGAN TEKNIK PA-MOCVD Sutanto, Heri; Subagio, Agus; Supriyanto, Edy; Arifin, Pepen; Sukirno, Sukirno; Budiman, Maman; Barmawi, Moehamad
Jurnal Sains Materi Indonesia EDISI KHUSUS: OKTOBER 2006
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (292.957 KB) | DOI: 10.17146/jusami.2006.0.0.5183

Abstract

STUDI PENGARUH KONSENTRASI AL PADA STRUKTUR KRISTAL DAN MORFOLOGI FILM TIPIS AlxGa1-xN/Si(111) YANG DITUMBUHKAN DENGAN TEKNIK PA-MOCVD. Film tipis AlxGa1-xN telah ditumbuhkan di atas substrat Si tipe-p dengan menggunakan teknik PA-MOCVD. Film tipis AlxGa1-xN ditumbuhkan dengan parameter-parameter: suhu substrat, laju alir N2, TMGa dan TMAl berturut-turut sebesar 700 oC; 90 sccm; 0,1 sccm dan 0,01sccm hingga 0,04 sccm. Film polikristal AlxGa1-xN yang ditumbuhkan mempunyai struktur heksagonal dengan bidang difraksi dominan (1010) dan (1011) hingga konsentrasi Al sebesar 6,78%. Diperoleh nilai kekasaran permukaan film dari pengukuran SPM pada range 11,44 nm sampai dengan 27,20 nm. Morfologi permukaan film semakin halus dengan peningkatan konsentrasi Al pada film. Penurunan nilai konstanta kisi hasil pengujian XRD terjadi karena kekosongan nitrogen pada film. Peningkatan konsentrasi Al pada film menyebabkan penurunan laju penumbuhan film tipis AlxGa1-xN yang terbentuk.
SINTESIS LAPISAN TIPIS NANOKOMPOSIT TiO2/CNT MENGGUNAKAN METODE SOL-GEL DAN APLIKASINYA UNTUK FOTODEGRADASI ZAT WARNA AZO ORANGE 3R Sakti, Rizky Bimanda; Subagio, Agus; Sutanto, Heri
Youngster Physics Journal Vol 2, No 2 (2013): Youngster Physics Journal April 2013
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Abstract

Nanocomposite thin film of TiO2/CNT as a photocatalyst material was  synthesized using the sol-gel method with the dispersion of commercial TiO2 Merck in CNT. The crystal structure and nanocomposite thin film morfology of TiO2/CNT were characterized using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Sol TiO2 0.3 M was mixed into the sol CNT with mass ratio of CNT:TiO2 was 1:5. Sol TiO2/CNT was sprayed on a glass substrate that was  heated at a temperature of 250 oC, then it was heated at the temperature of 450 °C for 60 minutes. Photodegradation was done by dipping the nanocomposite thin film of TiO2/CNT into 100 mL Azo Orange 3R dye sol 10 ppm, then was irradiated using UV light with a wavelength 380 nm. XRD pattern analysis showed that TiO2 has anatase structure with crystallite size at the range from 72-92 nm by using Scherrer equation. SEM image analysis showed that the grains of TiO2 sfreris pattern and was dispersed on CNT. Refluks TiO2/CNT nanocomposite thin film had been able to degrade Azo Orange 3R dye sol for 12 hours until percentage of 98,2% which was much better than the non reflux TiO2/CNT nanocomposite thin film as 97,2% and the TiO2 thin film as 90,9%. Keywords : TiO2, carbon nanotubes, thin film, nanocomposite, photodegradation, Azo Orange 3R dye.
Pengaruh Temperatur dan Waktu Kabonisasi pada Sintesis Porous Carbon Berbahan Dasar Molase Pertiwi, Asti Ayuk Putri; Pardoyo, Pardoyo; Subagio, Agus
Jurnal Kimia Sains dan Aplikasi Vol 12, No 3 (2009): Volume 12 Issue 3 Year 2009
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (812.654 KB) | DOI: 10.14710/jksa.12.3.93-97

Abstract

Telah dilakukan penelitian tentang pengaruh temperatur dan waktu karbonisasi pada sintesis porous carbon berbahan dasar molase. Molase merupakan hasil samping pabrik gula yang memiliki kandungan sukrosa yang sudah tidak dapat dikristalkan lagi. Penelitian ini dilakukan menggunakan molase sebagai sumber karbon dan tetrametilamonium klorida sebagai pencetak pori dengan range temperatur karbonisasi pada 500 - 650°C, sedangkan range waktu karbonisasi adalah 30-180 menit. Untuk pengujian adsorptivitas porous carbon hasil variasi waktu digunakan gas benzena. Analisis permukaan dari porous carbon yang dihasilkan dilakukan dengan SEM (Scanning Electron Microscopy) untuk mengamati morfologi permukaan dan BET (Bruanuer Emmet Teller) untuk mengetahui luas permukaan dan volume pori. Dari hasil penelitian diperoleh porous carbon dengan jumlah dan morfologi molekul yang cenderung meningkat seiring dengan peningkatan temperatur, temperatur optimum diperoleh pada 600°C. Sedangkan waktu karbonisasi dan kemampuan adsorpsi terbaik diperoleh pada waktu 180 menit dengan luas permukaan 265,38 m2/gram, volume pori 187,65 x 10-3 cc/gram dan adsorptivitas sebesar 5,39 x 10-3 mol/gram.
Sintesis dan Karakterisasi TiO2 Terdoping Nitrogen (N-Doped TiO2) dengan Metode Sol–Gel Karim, Slamet; Pardoyo, Pardoyo; Subagio, Agus
Jurnal Kimia Sains dan Aplikasi Vol 19, No 2 (2016): Volume 19 Issue 2 Year 2016
Publisher : Chemistry Department, Faculty of Sciences and Mathematics, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (676.007 KB) | DOI: 10.14710/jksa.19.2.63-67

Abstract

Energi celah pita yang lebar dari semikonduktor TiO2 yang setara dengan cahaya ultraviolet (l<380 nm) membatasi aplikasi fotokatalitik hanya terbatas pada daerah ultraviolet dan tidak pada daerah cahaya tampak (l = 400 nm–700 nm). Pada penelitian ini dilakukan sintesis TiO2 teremban nitrogen yang dipreparasi melalui metode sol-gel. Prekursor TiCl4 digunakan sebagai sumber titanium dioksida dan CO(NH2)2 sebagai sumber nitrogen dan divariasi pada jumlah konsentrasi N dengan variasi 20 g, 30 g, 40 g dan 50 g. Refluks dilakukan pada suhu 100oC selama 7 jam dilanjutkan dengan pengeringan selama 3 jam pada suhu 100oC, dan kalsinasi pada suhu 500oC selama 7 jam . Karakterisasi N-doped TiO2 dilakukan menggunakan X-ray Diffraction (XRD), Fourier Transform–Infra Red spectroscopy (FTIR), dan UV- Visible diffuse reflectance spectra (UV-Vis DRS). Berdasarkan data XRD diketahui bahwa kristal N- doped TiO2 berstruktur anatase dengan indeks Miller 101. Spektra FTIR menunjukkan pergeseran serapan vibrasi O-Ti-O pada bilangan gelombang 400-1050 cm-1, diperkirakan sebagai akibat terbentuknya ikatan N-Ti-O. Spektrum DRS-UV–tampak menunjukkan penurunan energi celah pita dari TiO2 yakni 3,2 eV. Dapat disimpulkan bahwa penambahan konsentrasi nitrogen mengakibatkan penurunan energi celah pita, pada variasi 20g sebesar 3,12 eV, 30 g sebesar 3,09 eV, 40 g sebesar 3,082 eV, dan 50 g sebesar 3,08 eV.
Fotokatalitik ZnO:KA pada Penjernihan Air Kali Banger Semarang Hidayatuloh, R; Subagio, Agus; Nurhasanah, I
JURNAL SAINS DAN MATEMATIKA Volume 20 Issue 4 Year 2012
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

Fotokatalis ZnO yang dikombinasikan dengan karbon aktif (ZnO:KA) digunakan pada proses penjernihan dan penghilang bau busuk air kali Banger. ZnO dilapiskan pada karbon aktif dengan memasukkan karbon aktif ke dalam larutan ZnO, kemudian dipanaskan pada temperatur 100oC selama 3 jam.  Mikrostruktur dan komposisi atom ZnO:KA diamati menggunakan scanning electron microscope (SEM) yang terintegrasi dengan energy dispersive x-ray spectroscope (EDX).  Citra SEM menunjukkan bahwa  ZnO telah berhasil dilapiskan pada permukaan KA.  Proses fotokatalis dilakukan pada penjernihan dan reduksi bau busuk air kali Banger dengan pemberian radiasi sinar UV.  Fotokatalitik ZnO:KA diuji melalui pengukuran total dissolved solid (TDS) dan biological oxygen demand (BOD).  Penurunan TDS air  kali Banger yang dijernihkan menggunakan sinar UV dan ZnO:KA lebih rendah dibandingkan dengan media lainnya. Kombinasi antara ZnO dan KA yang disinari UV juga menurunkan BOD air limbah kali Banger. Hasil tersebut menunjukkan bahwa ZnO:KA dapat digunakan untuk proses penjernihan air.   Keywords:ZnO,Karbon Aktif, fotokatalis, penjernihan air, kali Banger
Modification Effect of Carbon Nanotubes by LiCl (CNTs/LiCl) on the Electrical Conductivity Character Yuliastuti, Indri; Pardoyo, Pardoyo; Subagio, Agus
JURNAL SAINS DAN MATEMATIKA Volume 23 Issue 1 Year 2015
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

Carbon nanotubes have been modified by mass percentage variation of LiCl using reflux method. Mass percentage variation used in this study was 0, 1, 5, and 15%. The purpose of this study was to determine the effect of LiCl dope on the electrical conductivity of carbon nanotubes. This research was used reflux method by heating at 80°C for 24 h. The products produced were in the form of CNTs / LiCl dry powders. The characterization results of FT-IR spectroscopy showed that there was a Li-O bond group in the addition of 1, 5, and 15% LiCl while XRD characterization results did not show any diffraction of lithium chloride. The results of this study showed an increase in electrical conductivity at 15% addition of LiCl which was of 2.69 x 10-3 S/m. Electrical conductivity in the addition of 1% and 5% LiCl decreased (1.17 x 10-6 S/m and 2.64 x 10-6 S/m) from CNTs/LiCl 0% (3.68 x 10-6 S/m) due to the influence of the PVA high resistivity used as an adhesive in the pellets fabrication.
Solving a system of linear equations by QR Factorization Method for Temperature and Altitude Regression Model against Spontaneous-Potential Widowati, Widowati; Setyawan, Agus; Mustafid, Mustafid; Nur, Muhammad; Sudarno, Sudarno; Harmoko, Udi; Adhy, Satriyo; Gunawan, Gunawan; Subagio, Agus; Tjahjana, Heru; Sulpiani, Ririn; Riyanto, Djalal Er; Suhartono, Suhartono; Mukid, Mochammad Abdul; Suseno, Jatmiko Endro
JURNAL SAINS DAN MATEMATIKA Volume 22 Issue 3 Year 2014
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

Many real problems can be represented in the form of multiple linear regression equation. One of those is the relationship between the variables of temperature and altitude of the spontaneous-potential. In order to determine the parameters of the regression equation, the least squares method was used. From here, there was obtained the system of linear equations. In this paper, to solve systems of linear equations, the exact method was used as the exact solution is certainly better than the approached solution. The method used was the QR factorization method. At the QR factorization, the system of linear equations was written in form of matrix equation. Then, the coefficient matrix which the number of rows is m and number of columns is n with linearly independent columns was factored into the matrix Q which has the same size with the matrix A, with orthonormal columns and matrix R was upper triangular. Furthermore, by backward substitution, it could be obtained the exact solution of linear equation system. As verification of this proposed method, a case study was given using data of temperature, altitude, and spontaneous-potential in the geothermal manifestations area, Gedongsongo, Mount Ungaran Semarang. From here, it was obtained the parameters of exact multiple linear regression model which states the relationship between temperature and altitude toward the spontaneous-potential.
STUDI KARAKTERISTIK KELISTRIKAN KOMPOSIT CARBON NANOTUBE-POLYVYNILIDENE-FLOURIDE (CNT-PVDF) Rohman, Maulidanir; Subagio, Agus
Youngster Physics Journal Vol 2, No 2 (2013): Youngster Physics Journal April 2013
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Abstract

Development of nanomaterial technology strongly supports advancements in composite technology. Composite that use nanomaterial produce better electrical properties than common composite. Carbon nanotubes (CNT) is one of nanomaterial with high conductivity, so it’s potentially used in composite for various aplication. This research combines Carbon Nanotubes (CNT) with Polyvynilidene Flouride (PVDF) for producing CNT-PVDF composite with high conductivity. CNT-PVDF composites were fabricated by solution processing method. PVDF was dissolved into distillated aceton then CNT was dissolved in acetone and added Triton X-100 4 ml. PVDF solution and the solution of CNT were stirred for 1 hour using a magnetic stirrer, then both were mixed and stirred at temperature of 40 ° C until the acetone evaporates. Composites were molded using a hot-pressing at a pressure of 1 MPa and a temperature of 200oC for 10 minutes. CNT-PVDF composite were characterized by a conductivity test to generate conductivity values​​. The results of the analysis of the test showed that the addition of CNT conductivity on CNT-PVDF composite increased conductivity values​​. In the mass percentage of CNT 2%, 4%, 6%, and 8% conductivity increased slowly. Improved high conductivity of CNTs obtained in the mass percentage of 10%. Key word : Carbon Nanotubes, Polyvynilidene Flouride, composite, and conductivity
Pembuatan dan Karakterisasi Komposit CNT/PVA Setyaningsih, Metri; Widiyandari, Hendri; Subagio, Agus
JURNAL SAINS DAN MATEMATIKA Volume 21 Issue 3 Year 2013
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

Komposit CNT/PVA telah dibuat dengan metode solution processing. Polyvinyl alcohol (PVA) dilarutkan dalam akuades bertemperatur 80°C, dan kemudian carbon nanotubes (CNT) ditambahkan ke dalam larutan tersebut dengan berbagai variasi rasio fraksi massa CNT/PVA sebesar 10, 20 dan 30%. Komposit CNT/PVA terbentuk setelah dikeringkan dalam oven bertemperatur 90°C. Sifat mekanik komposit CNT/PVA dikarakterisasi dengan uji tarik. Komposit CNT/PVA yang memberikan sifat mekanik terbaik selanjutnya digunakan sebagai acuan dalam pembuatan komposit dengan variasi ketebalan. Komposit dengan variasi ketebalan dibuat dengan 3 metode yaitu cetak tebal, cetak lapis tebal dan cetak lapis tipis. Analisis dari uji tarik menunjukkan bahwa komposit CNT/PVA dengan fraksi massa 20% CNT/PVA  menghasilkan modulus Young yang paling besar yaitu 137,710348 MPa. Metode cetak lapis tipis menunjukkan peningkatan yang lebih besar dibandingkan dengan metode cetak tebal, dan cetak lapis tebal. Komposit dengan 3 lapis dan ketebalan 0,94 mm menghasilkan modulus Young sebesar 212,825166 MPa dan peningkatan  modulus Young komposit CNT/PVA terhadap modulus Young dari PVA sampai 107,30%.
The Effect of BaCO3 Compound Changes on the Formation of Magnetic Material BaFe12O19 Priyono, Priyono; Cahyono, Agung; Marhaendrajaya, Indras; Subagio, Agus; Gunawan, Vincensius
JURNAL SAINS DAN MATEMATIKA Volume 23 Issue 4 Year 2015
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

BaFe12O19 is a permanent magnetic material which has superior properties to be excellent until the late of twentieth century. Some of the obstacles in the synthesis of the material using a stoichiometric composition is a difficulty to obtain a single phase and the second phase is always found. This research attempted to make modifications on the initial non-stoichiometric composition by varying the fraction of Ba/Fe through BaCO3 and Fe2O3 compound through solid state reaction mechanism. This solid state reaction was initiated by mixing various fractions of BaCO3 and Fe2O3 powder composition and compacted to produce a homogeneous mixture using a planetary milling. After drying and molding, it was obtained a homogeneous mixture like a cylinder with a diameter of 2:54 cm and a thickness of 0.5 cm. The BaFe12O19 phase was obtained by heating the sample at a temperature of 1200 ° C for 4 hours. To determine changes in the fraction of Ba/Fe before and after sintering, the samples were tested by X-Ray Fluorescence (XRF), while the structure and crystallinity were tested by X-ray diffraction (XRD) and Scanning Electron Microscope (SEM). The results showed that during the heating process, the reduction of barium fractions exceeded 5% from of their initial weight, while changes in the fraction of Fe was not significant. The results of structure and crystallinity measurement showed that the addition a substantial amount of barium carbonate can lead to the decrease of crystallinity from 35.271 nm to 11.265 nm.