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All Journal Physics Student Journal Rekayasa Mesin Journal of Environmental Engineering and Sustainable Technology Natural B JPSE (Journal of Physical Science and Engineering) Jurnal Penelitian Pendidikan IPA (JPPIPA) INDONESIAN JOURNAL OF APPLIED PHYSICS

D. J. Djoko Herry Santjojo

Jurusan Fisika, Fakultas Matematika Dan Ilmu Pengetahuan Alam, Universitas Brawijaya

Author-ID : 370577

Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Control & Systems Engineering Decision Sciences, Operations Research & Management Education Electrical & Electronics Engineering Energy Environmental Science Materials Science & Nanotechnology Mechanical Engineering Physics

Published : 20 Documents Claim Missing Document

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ONE DIMENSIONAL SIMULATION OF DC BIASED ARGON PLASMA USING COMSOL MULTIPHYSICS Dionysius Joseph Djoko Herry Santjojo
Journal of Environmental Engineering and Sustainable Technology Vol 5, No 1 (2018)
Publisher : Lembaga Penelitian dan Pengabdian kepada Masyarakat Universitas Brawijaya

The character of a argon plasma in a DC biased reactor was simulated using 1-dimensional model. The model and simulation was carried out using COMSOL multiphysics software. Results of the simulation show that the model and can be used to predict the character and state of the Ar plasma such as distribution of electron density and Ar+ ion, electron temperature, and electric potential in the plasma space. Furthermore, the model predicts that the argon plasma is formed near the cathode (r<0.5 cm) at the end of the simulation. And, the higher the pressure the higher the plasma density produced at pressures less than 100 Pa.

EFFECT OF CHAMBER PRESSURE ON ELECTRICAL IMPEDANCE OF A LOW-FREQUENCY NITROGEN PLASMA IN A MEDIUM VACUUM REACTOR Dionysius Joseph Djoko Herry Santjojo
Journal of Environmental Engineering and Sustainable Technology Vol 4, No 2 (2017)
Publisher : Lembaga Penelitian dan Pengabdian kepada Masyarakat Universitas Brawijaya

The character of a low-frequency nitrogen plasma in a medium vacuum reactor was studied by determining the effect of chamber pressure on the electrical impedance of the plasma. The system understudied was a mini capacitive plasma reactor utilizing 40 kHz generator. The pressure was varied from 0.4 – 4.7 torrs. Results of this work indicated that the pressure in the range significantly affects the electrical impedance. The increase of the chamber pressure decreased the capacitive reactance while increased the resistance. The capacitive plasma indicates the plasma was controlled by excitation and ionization process, while the resistive plasma exhibits complex reactions due to collisions.

Pengaruh Laju Alir terhadap Karakter Plasma dan Sifat Hidrofobisitas Lapisan Polistirena di atas QCM Menggunakan Metode RF dengan DC Bias Abu Bakar; Masruroh Masruroh; Djoko Herry Santjojo
Natural B, Journal of Health and Environmental Sciences Vol 5, No 2 (2019)
Publisher : Natural B, Journal of Health and Environmental Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar

Telah dilakukan perlakuan plasma nitrogen menggunakan metode RF dengan DC bias plasma di atas permukaan polistiren dengan variasi laju alir. Tujuan dari penelitian ini untuk mempelajari pengaruh laju alir terhadap sifat hidrofobisitas permukaan polistirena di atas quartz crystal microbalance (QCM) sensor. Polistirena dilarutkan dengan pelarut toluena dan dideposisikan di atas permukaan QCM dengan teknik spin coating. Perlakuan plasma nitrogen dilakukan dengan variasi laju alir 20, 30, 40, 50, 60, 65 dan 70 ml/menit, dan parameter tekanan pada 40 Pa, tegangan RF 90 volt, DC bias 400 volt. Spesies plasma berupa panjang gelombang dan intensitas diukur dengan optical emission spectroscopy (OES) Aurora 400. Sifat hidrofobisitas polistirena diukur dengan contact angle measurement dan gugus fungsi C≡N diobservasi dengan Fourier transform infrared (FTIR). Hasil OES berupa panjang gelombang dan intensitas dicocokkan dengan NIST atomic database, dan didapatkan spesies plasma paling dominan yang terdeteksi merupakan spesies radikal atom N pada panjang gelombang 388 nm dan 424 nm, dan NIII ( ) pada panjang gelombang 334 nm. Hasil pengukuran sudut kontak mengalami kecenderungan perubahan yaitu sudut kontak naik sampai laju alir 50 ml/menit dan turun sampai 70 ml/menit. Nilai perubahan sudut kontak untuk pengaruh laju alir menunjukkan nilai kurang dari 90°, sehingga permukaan bersifat hidrofilik. Hasil observasi dengan FTIR ditemukan gugus fungsi C≡N pada permukaan polistirena setelah dilakukan perlakuan plasma. Gugus Fungsi C≡N terbentuk dikarenakan interaksi spesies plasma berupa radikal atom N dan ion N2+ yang menumbuk permukaan polistirena. Gugus fungsi C≡N bersifat polar sehingga memberikan perubahan pada sifat hidrofobisitas permukaan polistirena.

Preparation of Chitosan-Fe3O4 Nanoparticles by Ex-Situ Co-Precipitation Using Tripolyphosphate / Sulfate as Crosslinker and Characterization Using XRD Ika Oktavia Wulandari; Akhmad Sabarudin; Djoko Herry Santjojo
Natural B, Journal of Health and Environmental Sciences Vol 3, No 3 (2016)
Publisher : Natural B, Journal of Health and Environmental Sciences

Magnetic nanoparticles of Fe3O4 was synthesized in this research by using ex-situ copresipitation method followed by surface modification with crosslinked chitosan along with trypolyphospate (TPP) and sulfate crosslinking agents. The Fe3O4 materials were formed from FeCl2.H2O and FeCl3.6H2O with 1:2 ratio under alkaline condition. Surface modification processes were conducted by mixing chitosan solution with purified Fe3O4 yielding a ferrogel solution as a product. Here, the crosslinker agents, TPP and sulfate, were added to the mixture to make a crosslinking compounds. In these processes, the chitosan-Fe3O4 crystallite size were affected by composition ratio and crosslinking time which will be proven by using x-ray diffraction (XRD) and modified Debye-Scherrer methods. The results showed that, on highest ratios between chitosan and Fe3O4 as well as TPP/sulfate crosslinker, gave the smallest size of crystallite of chitosan-Fe3O4. Furthermore, the more time of crosslinking process caused crystallite size of chitosan-Fe3O4 became much smaller.

Study of Stearic Acid Layer (SA) Microstructure on Surface Quartz Crystal Microbalance (QCM) Sensors Nurramdaniyah Nurramdaniyah; Masdiana Padega; Djoko Herry Santjojo; Setyawan P. Sakti; Masruroh Masruroh
Natural B, Journal of Health and Environmental Sciences Vol 4, No 2 (2017)
Publisher : Natural B, Journal of Health and Environmental Sciences

In the development of QCM-based biosensor sensors, the sensor surface is a very important part because it determine how the surface interacting with its environment especially during the immobilization of biomolecules process. In the utilization of QCM as biomolecule detecting biosensor, it is necessary to coat the polymer material on the surface of QCM. A stearic acid layer is used as an immobilization matrix layer because stearic acid has both polar and non polar properties so it can interact with biomolecules. The stearic acid layer is deposited on the polystyrene surface using a vacuum evaporation method. A study of the microstructure of the stearic acid coating was conducted to determine the possibility of the deposited stearic acid layer used as the matrix layer. In this research, microstructural study of layers of the stearic acid by using Scanning Electron Microscope (SEM) was carried out to find out the surface morphology of stearic acid. X-Ray Difraction (XRD) measurements were conducted to identify the crystal structure of stearic acid while Fourier Transform Infrared (FTIR) measurements were used to determine the stearic acid functional group. The Scanning Electron Microscope (SEM) results show the surface of the cavity and pore layers of the polystyrene layer was coated with white fibers homogeneously deposited on the surface of QCM / Polystyrene. Furthermore, the X-Ray Difraction (XRD) results showing a spectrum peak at an angle of 2q = 26,66° indicates the existence of stearic acid crystals. Whereas, the measurement results of the Fourier Transform Infrared (FTIR) indicate the appearance of C-H functional groups at a wavelength value of 3600-2600 cm-1 which indicates the functionality of the stearic acid layer.

Preparation of Chitosan-Fe3O4 Nanoparticles by In-situ Co-Precipitation Using Tripolyphosphate / Citrate as Crosslinker and Characterization Using XRD Vita Tria Mardila; Akhmad Sabarudin; Djoko Herry Santjojo
Natural B, Journal of Health and Environmental Sciences Vol 3, No 3 (2016)
Publisher : Natural B, Journal of Health and Environmental Sciences

Chitosan-Fe3O4 nanoparticles have been synthesized in a one pot reaction by combine TPP: citrate as crosslinker. The method was in-situ co-precipitation of iron salts in the presence of chitosan and crosslinker. The aim of this study was to determine the effect of preparation process towards chitosan-Fe3O4 nanoparticles characteristics which was prepared on several preparation condition: chitosan:Fe(II):Fe(III) ratio, TPP:citrate ratio, and crosslinking time. The crystallite sizes of the Fe3O4 and chitosan- Fe3O4 nanoparticles was obtained from modified Debye Scherrer equation using data from XRD analysis. The crystallite size of the bare-Fe3O4 and chitosan-Fe3O4 nanoparticles were found to be about 6.22 and 9.49 nm, respectively. XRD analysis results shown that beside Fe3O4 phases there was γ-Fe2O3 phase due to the oxidation of Fe3O4.The crystallite sizes and the percentage of Fe3O4 decreases with increasing number of chitosan coating the Fe3O4 and the length of crosslinking time

PFRET Measurements Using Sensitized Emission Methods in Observation of Calcium Changes in Oocytes Nathania Nanasari; Djoko Herry Santjojo; Chomsin Sulistiya Widodo; Hari Soepriandono
Natural B, Journal of Health and Environmental Sciences Vol 2, No 4 (2014)
Publisher : Natural B, Journal of Health and Environmental Sciences

Fluorescence Resonance Energy Transfer (FRET) is a process of non-radiative energy transfer from donor molecule to an acceptor. We expect to know the quantitative FRET measurements in immature and mature goat oocyte with the presence of calcium. FRET was detected using a laser scanning confocal microscope. We assume that calcium as a donor and fluo-3 as an acceptor. The methods of sensitized emission have been used for quantitative FRET measurement. We also describe the precision FRET (PFRET) data analysis. The value of PFRET describe the presence of calsium in immature and mature oocytes. For these immature and mature oocytes, the results of PFRET are 622,5 and 754,57 respectively. Mature oocyte has more calsium than immature oocyte.

Identifikasi Spesies Reaktif yang Dihasilkan Plasma Nonthermal lucutan penghalang dielektrik permukaan dengan Variasi Sumber Gas (Udara, N2, O2) untuk Membunuh Bakteri Renaldo Apriandi Kasa; Unggul Pundjung Juswono; Dionysius Joseph Djoko Herry Santjojo
Jurnal Penelitian Pendidikan IPA Vol. 8 No. 4 (2022): October
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v8i4.2167

Non-thermal plasma is one of the new techniques that is being focused on in the medical world, one of which is used for sterilization because non-thermal plasma is known to have a bactericidal effect. Reactive species produced by non-thermal plasma are antimicrobial. One factor affecting plasma species' reactive composition is the gas source used. Therefore, this study aimed to determine the effect of reactive species produced from non-thermal plasma generation of SDBD using different gas sources, namely free air, oxygen, and nitrogen, in treating Escherichia Coli bacteria. The gas flow used is 1 liter/minute. Reactive species produced by plasma were characterized using Optical Emission Spectrometry (OES). SDBD Non-thermal plasma treatment for Escherichia Coli bacteria samples was repeated three times for each treatment, and then the Anova test was performed. The results of this study indicate that bacterial death at the decontamination level depends on the composition of the gas used during treatment. Plasma using an O2 gas source has a more effective inactivation ability, namely 6 x 107 CFU/ml, compared to the control, which is 409 x 107 CFU/ml. At the same time, the treatment results with free air and nitrogen gas sources were 6.33 x 107 CFU/ml and 41.67 x 107 CFU/ml. These results indicate that the composition of ROS and RNS influences bacterial inactivation, where ROS is more effective in inactivating bacteria than RNS

Morphological and Mechanical Study of Gelatin/Hydroxyapatite Composite based Scaffolds for Bone Tissue Regeneration Moh Rifqi Nawafi; Masruroh Masruroh; Dionysius Joseph Djoko Herry Santjojo
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 12, No 2 (2022): IJAP Volume 12 ISSUE 02 YEAR 2022
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v12i2.59365

Gelatin-Hydroxyapatite (GHA) composite has been synthesized as a scaffold in bone tissue engineering. The purpose of this study was to find the optimal composition of the GHA scaffold composite which has the best mechanical properties. The independent variable in this study was the composition of HAp. Hydroxyapatite was synthesized by precipitation method from Ca(OH)2 and (NH4)2HPO4 as raw materials. Scaffold from GHA Composite was made by freeze-drying technique with freezing time for 8 hours at -80º C and drying with lyophilizer. The results were characterized using XRD, optical microscopy and tested for compressive strength. The results of the XRD showed that there was no change in a compound or the formation of new bonds on the GHA scaffold when it became a composite which was indicated by the absence of new peaks. It is also known that the peaks decrease in intensity as the amount of polymer in the composite increases. The highest degree of crystallinity was found in the 1:3 GHA sample because it had the highest concentration of HAp. The results of observations with an optical microscope showed that the most homogeneous pore surface morphology was GHA 1:2 with an average pore size of 225.12 ± 16.57 μm. From the results of the compressive strength test, the best value for the 1:2 GHA scaffold was 18.1 ± 0.61 MPa. The values obtained by this scaffold are following the minimum requirements for canceled scaffold so that it can be used as a scaffold candidate in bone tissue engineering.

Oxygen Gas Vacuum Plasma Treatment on PVA/Chitosan/HAp Scaffold Nanofiber Hartatiek Hartatiek; Nada Shofura Faradyana; Maulia Ingganis Wuriantika; Yudyanto Yudyanto; Muhammad Nurhuda; Masruroh Masruroh; Dionysius Joseph Djoko Herry Santjojo; Norhayati Ahmad
JPSE (Journal of Physical Science and Engineering) Vol 7, No 2 (2022): JPSE (Journal of Physical Science and Engineering)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar

Scaffold in the form of nanofibers in bone tissue engineering applications continues to be developed. In this study, nanofibers are composed of PVA/CS/HAp with characteristics that can support medical applications such as bone tissue engineering. Vacuum plasma treatment was carried out to modify the nanofiber surface. The results of the morphological analysis showed that the vacuum plasma treatment of oxygen gas caused the surface of the PVA/CS/HAp nanofibers to become rougher with a change in diameter. Before the oxygen gas vacuum plasma treatment, the diameter of the nanofiber had a range of 83–365 nm. After the oxygen gas vacuum plasma treatment, the diameter had a size range of 105–293 nm. Furthermore, the vacuum plasma treatment carried out showed increased hydrophilic properties. The average contact angle values before and after oxygen gas vacuum plasma treatment were (39.0 ± 0.0005)° and (10.3 ± 0.0005)°, respectively.DOI: 10.17977/um024v7i22022p108

Co-Authors abdurrouf Abdurrouf Abu Bakar Agus Naba Akhmad Sabarudin Arinto Y.P. Wardoyo Budy Wiryawan Chomsin Sulistiya Widodo Edi Purnama Hari Soepriandono Hartatiek, Hartatiek Iin Hidayanti Wulansari Ika Oktavia Wulandari Ikhsani, Ridha N. Inggita I.H. Putri Masdiana Padega Masruroh Masruroh Masruroh Masruroh Masruroh Masruroh Masruroh Masruroh Masruroh MASRUROH Maulia Ingganis Wuriantika Moh Rifqi Nawafi Muhammad Fadlil Khoironi Muhammad Nurhuda Nada Shofura Faradyana Nathania Nanasari Norhayati Ahmad Nurramdaniyah Nurramdaniyah rahmatia putri Ratih Endah Sutantri Renaldo Apriandi Kasa Ridwan Awalin Rizky Benny Relado, Rizky Benny Sakti, Setyawan P. Setyawan P. Sakti Unggul P Juswono Unggul Pundjung Juswono Vita Tria Mardila Winarto Winarto Windajanti, Josephine Maria Yudyanto Yudyanto

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