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Agus Subagio
Department Of Physics, Faculty Of Science And Mathematics, Universitas Diponegoro, Semarang
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PEMBUATAN KOMPOSIT CARBON NANOTUBE-POLYVINYL ALCOHOL (CNT-PVA) SERTA EVALUASI SIFAT MEKANIKNYA Wahyudi, Tatang; Setyaningsih, Metri; Subagio, Agus; Widiyandari, Hendri; Pardoyo, Pardoyo; Ahyani, Musni
Arena Tekstil Vol 27, No 1 (2012)
Publisher : Arena Tekstil

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Abstract

Perkembangan teknologi nanomaterial mendukung teknologi komposit. Komposit yang menggunakannanomaterial menghasilkan sifat mekanik yang lebih baik daripada komposit biasa. Komposit carbon nanotubes(CNT) berpotensi memiliki kekuatan tarik yang tinggi oleh adanya struktur tabung nanonya yang baik sebagaimatrik. Komposit CNT-PVA telah dibuat dengan metode pelarutan. Polyvinyl alcohol (PVA) dilarutkan dalam airbertemperatur 80°C, selanjutnya material CNT ditambahkan ke dalam larutan tersebut dengan variasi fraksi massaCNT terhadap PVA sebesar 10%, 20% dan 30%. Komposit CNT-PVA terbentuk setelah dikeringkan padatemperatur 80°C. Selanjutnya sifat mekanik komposit dikarakterisasi dengan uji kekuatan tarik. Hasil ujimenunjukkan bahwa komposit CNT-PVA dengan fraksi massa 20% CNT terhadap PVA menghasilkan modulusYoung yang paling besar yaitu 137,71MPa. Ketebalan komposit 0,94 mm yang dibangun oleh tiga lapis tipiskomposit CNT-PVA menghasilkan peningkatan modulus Young hingga 107,30%.
PEMBUATAN KOMPOSIT SERAT SERABUT KELAPA DAN RESIN FENOL FORMADEHIDE SEBAGAI MATERIAL PEREDAM AKUSTIK Kartikaratri, Yohana Maya; Subagio, Agus; Widyandari, Hendri
BERKALA FISIKA Vol 15, No 3 (2012): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

The sound pollution due to noise is a one clasical problem in Indonesia. Theloudness can be reduced using the accoustic absorber. The composites of coconut fiberhas potential application as an environmental friendly accoustic absorber which is usingan agriculture waste. We reported the preparation of composite of coconut fiber as amatrix material and fenol formaldehide served as binder (coconut fiber/FF composite).The  immersion of coconut fibers  in the NaOH solution of 2% for 4 hours were caried outpriorly for improving the strengthness.The absorption coefficient (α) of the preparedcoconut fiber/FF composite was observed using two microphone impedance tube method(ISO 10534 – 2 dan ASTM E1050 – 08.   The value of tested absorption coefficient (α) allof composites samples have fulfilled the requirement. Requirement of acoustic absorbervalue of α is more than 0,15; and all of composites samples fulfilled the requirement onfrequency 752 Hz - 6400Hz.  Keyword : absorption coefficient, acoustic absorber, composite, coconut fiber, fenolformaldehid.
Pembuatan Zeolit Nanopartikel dengan Metode High Energy Milling (Zeolite Nanoparticle Fabrication using High Energy Milling Method) Muhriz, Mohammad; Subagio, Agus; Pardoyo, Pardoyo
JURNAL SAINS DAN MATEMATIKA Volume 19 Issue 1 Year 2011
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

Pembuatan nanopartikel menggunakan metode high energy milling belum banyak dilakukan di Indonesia. Tujuan dari penelitian ini adalah membuat zeolit nanopartikel dari zeolit alam dengan metode high energy milling. Zeolit alam Wonosari digerus dan diayak menggunakan ayakan 250 mesh dan kemudian digiling dengan High Energy Milling-Ellipse 3D Motion (HEM-E3D) selama 0, 2, 4, dan 6 jam dengan kecepatan 1000 rpm dan ball to powder ratio (BPR) sebesar 8:1. Bentuk fisis dari zeolit sebelum dan sesudah milling terlihat sama dan sulit dibedakan. Hasil karakterisasi SEM menunjukkan adanya penurunan ukuran partikel dari Z-0 menjadi Z-6. Zeolit dengan waktu milling Z-6 mempunyai ukuran partikel terkecil yaitu sebesar 70-280 nm Karakterisasi dengan metode BET menunjukkan zeolit beraglomerasi yang ditandai dengan tidak adanya perubahan berarti pada luas permukaan spesifik, volume pori total, dan ukuran pori rata-rata semua sampel.   Keywords: high energy milling, zeolit alam, ukuran partikel
Synthesis of Carboxyl (CNT-COOH) and Ammine Carbon Nanotubes (CNT-NH2) Pardoyo, Pardoyo; Suharini, Sri Eny; Nandiyah, Siti; Subagio, Agus
JURNAL SAINS DAN MATEMATIKA Volume 23 Issue 2 Year 2015
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

A research synthesizing CNT-COOH to increase the compatibility character of carbon nanotubes and CNT-NH2 to increase the hydrophilic character has been done. The CNT-COOH was synthesized using ultrasonic bath method for 6 hours with the volume ratio of concentrated H2SO4 : HNO3 were 2:1, 3:1 and 4:1. Whereas CNT-NH2 was produced by refluxing CNT and ethylene diamine at temperature of 40°C, 60°C and 80°C. Both products were analyzed with Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS). The C=O bond on CNT-COOH was showed by wavenumber of 1635.64 cm-1 and the OH bond at 3448.72 cm-1 whilst the N-H bond emerged at 152762 cm-1. SEM and EDS indicated both products had surface morphology of tubes and reducing of Fe content which was the one of impurities of CNT.
Antibakteri Fotokatalis TiO2:KA untuk Sterilisisasi Air yang Tercemar Bakteri Escherichia Coli Taftiari, M F; Subagio, Agus; Nurhasanah, I
JURNAL SAINS DAN MATEMATIKA Volume 20 Issue 1 Year 2012
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

TiO2 yang dilapiskan pada karbon aktif granular (TiO2:KA) telah digunakan untuk mereduksi bakteri Escherichia coli (E. Coli) dalam air. Serbuk TiO2 merupakan material fotokatalis yang dapat mengurai polutan organik, seperti: bakteri E. Coli.  Namun   penggunaannya masih memerlukan proses pemisahan  TiO2 dari air.  KA telah banyak digunakan sebagai penyerap polutan dalam proses penjernihan air.  Pada penelitian ini KA granular digunakan sebagai media tempat pelapisan TiO2 untuk mereduksi bakteri E. coli.  TiO2:KA diperoleh dengan mencelupkan KA ke dalam larutan TiO2 kemudian dikeringkan pada temperatur 100oC selama 30 menit.  Mikrostruktur TiO2:KA diamati menggunakan x-ray difractometer (XRD) dan scanning electron microscope (SEM).  Kemampuan fotokatalis TiO2:KA dalam mereduksi E. coli diuji menggunakan total plate count (TPC) terhadap air yang telah melalui proses fotokatalis berbantuan sinar UV.  Citra SEM menunjukkan adanya bulir-bulir pada permukaan KA yang mengindikasikan TiO2 berhasil dilapiskan pada KA.  Hal ini diperkuat dengan pola difraksi yang menunjukkan struktur anatase TiO2.  Jumlah bakteri E. coli yang tereduksi meningkat seiring dengan lama waktu proses fotokatalis.  Proses fotokatalis TiO2:KA   selama 3 jam berhasil menghilangkan 100% bakteri E. coli dalam air.  Hasil ini menunjukkan efektivitas antibakteri fotokatalis TiO2:KA untuk sterilisasi air dari bakteri E. coli.   Keywords: antibakteri, Escherichia coli, fotokatalis, TiO2:KA
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.
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%.
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.
Co-Authors Adi Darmawan Agung Cahyono Agus Setyawan Ahmad Aviv Mahmudi Annisa Fadillah Aslam Fatkhudin Bayu Surarso Della Widya Puspita Djalal Er Riyanto Edy Supriyanto Eko Hidayanto Erma Prihastanti Febio Dalanta Hadi Endrawati Hella Arofah Hendri Widiyandari Hendri Widiyandari Hendri Widyandari Heri Sutanto Hermin Pancasakti Kusumaningrum Horasdia Saragih I Gusti Ngurah Antaryama I Nurhasanah Iis Nurhasanah Imam Misbach Indras Marhaendrajaya Indri Yuliastuti, Indri Jatmiko Endro Suseno Joko Sudarto Khasan Rowi M F Taftiari M. Imam Taufiq Maman Budiman Maman Budiman Maulidanir Rohman Metri Setyaningsih Metri Setyaningsih Moch. Abdul Mukid Moehamad Barmawi Moehammad Barmawi Mohammad Muhriz Muhammad Iskandar Zulkarnain Muhammad Nur Muhammad Zainuri Musni Ahyani Musni Ahyani, Musni Mustafid Mustafid Ngadiwiyana M.Si. S.Si. Ngurah Ayu Ketut Umiati Pardoyo - Pardoyo Pardoyo Pardoyo, Pepen Arifin Pepen Arifin Priyono Priyono Priyono, R Hidayatuloh R. Yudianti Redemtus Heru Tjahjana Rike Yudianti Rike Yudianti Rini Budihastuti Ririn Sulpiani Rizky Bimanda Sakti Romi Buana Puja Pangestu Satriyo Adhy Silviana Silviana Siti Nandiyah, Siti Skolastika Dara Sabatini Sri Eny Suharini, Sri Eny Sri Widodo Agung Suedy Subhan Subhan Subhan, Sudarno Sudarno Sudarto, Joko Sukirno Sukirno Sukirno Sukirno Tatang Wahyudi Tatang Wahyudi, Tatang Tri Windarti Udi Harmoko Vincensius Gunawan S.K. Weni Safitri Widianingsih Widianingsih Yohana Maya Kartikaratri Yundari, Yundari Yuvita Muliastuti