Article Per Year (5 Year)
p-Index From 2020 - 2025
0.817
P-Index
This Author published in this journals
All Journal ILMU KELAUTAN: Indonesian Journal of Marine Sciences BULETIN OSEANOGRAFI MARINA BERKALA FISIKA SAINS DAN MATEMATIKA Jurnal Kedokteran Diponegoro YOUNGSTER PHYSICS JOURNAL
Indras Marhaendrajaya
Physics Department, Faculty Of Sciences And Mathematics, Diponegoro University
Earth & Planetary Sciences Mathematics Medicine & Pharmacology Physics

Published : 18 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 18 Documents
Search

 1   2 
Studi Pengaruh Medan Radio Frekuensi (RF) pada Minyak Goreng Firdausi, K. Sofjan; Istianah, Istianah; Marhaendrajaya, Indras
BERKALA FISIKA Vol 11, No 1 (2008): Berkala Fisika
Publisher : BERKALA FISIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (243.936 KB)

Abstract

A study of non linier optic has been carried out for palm oil induced by RF frequency field,e using white light and laser light. The e’s value is produced by RF generator with 2kV of voltage and in the range of frequency between 6.04 MHz and 11 MHz. In this research, he-ne laser with 632.8 nm of wavelength, green pointer laser with 532 nm of wavelength and white light of halogen with maximum power 130, are used as source of light. The physical characteristics observed in the experiment are change of light polarization that is transmitted through palm oil. From experiment result indicates that the change of polarization angle is not linearly dependent on e, At the same condition, the highest changes of polarization angle takes place when providing green laser, upright position of RF frequency field on polarization angle direction  900 for the twice used-palm oil. Keywords: non – linier optics, polarization angle, RF frequency field
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

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (601.073 KB)

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.
Formation of Eco-friendly Silver Nanoparticle Microalgae using Chlorella vulgaris Hermin Pancasakti Kusumaningrum; Muhammad Zainuri; Widianingsih Widianingsih; Wahyu Dewi Utari Haryanti; Indras Marhaendrajaya; Robertus Triaji Mahendrajaya
ILMU KELAUTAN: Indonesian Journal of Marine Sciences Vol 24, No 1 (2019): Ilmu Kelautan
Publisher : Marine Science Department Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (524.582 KB) | DOI: 10.14710/ik.ijms.24.1.7-14

Abstract

Biosynthesized silver nanoparticles (AgNPs) using organism have spurred great interest as a antimicrobial and biomedical agents. Green microalgae have advantages as they are easily available, grow rapidly and producing varieties metabolites. Synthesized of AgNPs from  microalgae C. vulgaris offer environmentally antimicrobial agent. The objectives of the study is producing AgNPs microalgae using C. vulgaris as eco-friendly antimicrobial agent. The research methods was conducted by synthesizing silver nanoparticle microalgae using C. vulgaris following by characterization under UV–visible spectroscopy,  transmission electron microscopy  (TEM), and scanning electron microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDX). The research result showed AgNPs C. vulgaris microalgae were produced with and without agitation treatment under different condition. The synthesized AgNPs C. vulgaris exhibited a maximum absorption at 312 nm and 398 nm, and EDX analysis had determined that abundance chemical elements presented in a sample were carbon  and silver.  The TEM analysis revealed that they are spherical form. The spot of EDX analysis showed the presence of silver atoms. The SEM analysis shows the spherical shaped with some silver particle inside of the cell. These resut indicated that formation of silver nanoparticle microalgae using C. vulgaris has been succesfully obtained under the treatment. 
Effect of Silver Nano Particle Microalgae Chlorella pyrenoidosa and Dunaliella salina on Growth and Survival of Penaeus monodon Larvae Hermin Pancasakti Kusumaningrum; Muhammad Zainuri; Indras Marhaendrajaya; Agus Subagio; Widianingsih Widianingsih; Hadi Endrawati; Annisa Fadillah; Muhammad Iskandar Zulkarnain; Yuvita Muliastuti; Imam Misbach
Buletin Oseanografi Marina Vol 10, No 2 (2021): Buletin Oseanografi Marina
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/buloma.v10i2.35483

Abstract

Penaeus monodon is one of the most important farmed crustaceans. Its also known as Asia Tiger Shrimp because its carapace and abdomen are transversely banded with red and white. The use of synthetic antibiotic in aquaculture had caused problems related to health and environmental safety. Chlorella pyrenoidosa and Dunaliella salina are photosynthetic microalgae. Silver nano particle in microalgae C. pyrenoidosa and D. salina had synthesized and showed their growth stability. They offer a potency to be exploited to supported growth and survival of shrimp larvae. The objective of the study was the application of silver nano particle in microalgae C. pyrenoidosa and D. salina on P. monodon larvae. The research methodology was carried out by making microalgae C. pyrenoidosa and D. salina containing silver nano particle and used as feed of shrimp larvae. Observations were made on the growth and survival of shrimp larvae compared to both microalgae and common feed. The results showed that the P. monodon larvae  have the higher growth and survival rate with microalgae C. pyrenoidosa at the beginning of their growth compared to D. salina. However, microalgae without nanosilver and common feed showed a better result for growth and activity of shrimp larvae.
Desain dan realisasi alat pengukur kandungan kolesterol dalam darah non-invasive Indras Marhaendrajaya; Eko Hidayanto; Zaenal Arifin; Heri Sutanto
Youngster Physics Journal Vol 6, No 3 (2017): Youngster Physics Journal Juli 2017
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (785.557 KB)

Abstract

Excess total blood cholesterol can lead to heart vessel disorders, stroke and the most fatal can result in death. While testing the cholesterol levels in the blood at this time still use the invasive technique that the patient's blood is taken by using a syringe. This is one of the obstacles / causes of some patients are reluctant to check blood cholesterol. One of the health technologies to detect blood cholesterol in non-invasive is by utilizing the absorption of near infrared ray (NIR) and laser. The change in the physical properties of the resistance shows the chemical content of different solutions. Preparation of non-invasive blood cholesterol gauge by utilizing oxymeter sensor capable of producing voltage changes in various liquid medium and Atmega 8535 microcontroller as a minimum system in controlling output value in digital data form. The system or equipment to be fabricated in this study is a non-invasive method (without injuring the patient's body while taking blood samples) to determine the blood cholesterol content by utilizing the physical properties of laser absorption or NIR sensors on various blood cholesterol levels. From the research results have been made series of sensor interfaces and serial data communications are displayed digitally. The test results show that the equipment made has shown good performance but still limited its performance test. The results of the research will be developed into a national program of providing cheap, non-invasive portable and movable health test kits. Keywords: Heart Disease, Blood Cholesterol, NIR, Laser, Microcontroller.
KOMPARASI ENTRANCE SURFACE AIR KERMA (ESAK) DENGAN SOFTWARE CALDOSE_X DAN METODE TUBE OUTPUT PADA PASIEN THORAX DEWASA DALAM PEMERIKSAAN RADIOGRAFI UMUM BERDASARKAN DATA SI-INTAN Anugrah Rahma Ari Wiganti; Eko Hidayanto; Indras Marhaendrajaya; Pandji Triadyaksa
BERKALA FISIKA Vol 25, No 4 (2022): Berkala Fisika
Publisher : BERKALA FISIKA

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

Abstract

Kuantitas  operasional  dosimetri  didasarkan  pada  pengukuran  Entrance  Surface  Air  Kerma (ESAK),  baik  secara  langsung  dengan  thermoluminescence  dosimeter  (TLD)  maupun  tidak langsung dengan memanfaatkan keluaran radiasi pesawat sinar-X.  Namun, CALDose_X dan juga  metode  Tube  Output  mampu  melakukan  perhitungan  dosis  menggunakan  persamaan standar.  Penelitian  ini  bertujuan  untuk  menghitung  ESAK  pada  pemeriksaan  Thorax  radiografi umum  proyeksi  Anterior  Posterior  (AP)  dan  Posterior  Anterior  (PA)  berdasarkan  data  SI- INTAN  dengan  perangkat  lunak  CALDose_X  dan  metode  tube  output  serta  menganalisis perhitungan  ESAK  tersebut  dengan  nilai  Diagnostic  Reference  Level  (DRL).  Data  penelitian bersumber  pada  basis  data  SI-INTAN  Bapeten  yang  berupa  data  survei  pasien  dan  data  keluaran radiasi pada salah satu rumah sakit di Jawa Timur yaitu sebanyak 76 data proyeksi AP dan 111 data proyeksi  PA.  Data  diolah  menggunakan  CALDose_X  dan  metode  tube  output  serta  diuji menggunakan uji normalitas dan uji Wilcoxon. ESAK pada pemeriksaan thorax dewasa radiografi umum rumah sakit X proyeksi AP dengan CALDose_X sebesar 0,34±0,055 mGy dan metode tube  output  sebesar  0,33±0,059  mGy.  Sedangkan  proyeksi  PA  dengan  Caldose-X  yaitu sebesar  0,31±0,13  dan  metode  tube  output  sebesar  0,30±0,13  mGy.  ESAK  pemeriksaan Thorax  di  rumah  sakit  X  pada  CALDose_X  menunjukkan  tidak  ada  perbedaan  yang signifikan dengan metode tube output dan nilainya lebih rendah daripada DRL Indonesia.
Support Vector Machine, Naive Bayes, and Artificial Neural Network Back Propagation Comparison in Detecting Brain Tumor Triadyaksa, Pandji; Ahmad, Harisma Zaini; Marhaendrajaya, Indras
Jurnal Kedokteran Diponegoro (Diponegoro Medical Journal) Vol 13, No 4 (2024): JURNAL KEDOKTERAN DIPONEGORO (DIPONEGORO MEDICAL JOURNAL)
Publisher : Faculty of Medicine, Universitas Diponegoro, Semarang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/dmj.v13i4.45462

Abstract

Brain tumors are abnormal tissue that grow uncontrolled and affect a patient's neurological function. Brain tumors come in different shapes and characteristics. Moreover, its location also differs for each patient. Brain tumors can be detected using machine learning algorithms using magnetic resonance imaging (MRI) images. However, a different machine-learning comparison is limited and needs further investigation. This study aims to compare three machine-learning methods, i.e., Support Vector Machine (SVM), Naive Bayes (NB), and Artificial Neural Network Back Propagation (ANN-BP) algorithms for detecting brain tumors. Before the comparison started, MRI image quality was enhanced by performing denoising, histogram equalization, and thresholding. After that, Gray Level Co-occurrence Matrix feature extraction was performed. MRI brain images in JPEG format were acquired from an open-access database. One thousand brain tumor and 1000 normal tumor images are used as the training data, while 100 brain tumor and 100 normal tumor images are used as testing data. Each algorithm's accuracy, precision, sensitivity, and Matthews Correlation Coefficient (MCC) are evaluated and reported. The study showed that the SVM algorithm acquired the highest performance in detecting brain tumors, followed by ANN-BP and NB. The highest accuracy, precision, sensitivity, and MCC values for testing in SVM were 98,75%, 98,22%, 99,30%, and 0,9751, respectively. Meanwhile, in testing, the highest accuracy, precision, sensitivity, and MCC values were 90.50%, 98.80%, 82.00%, and 0.8220, respectively. In conclusion, this study showed the superiority of the SVM algorithm in detecting brain tumor compared to ANN-BP and NB by performing image enhancement steps and GLCM feature extraction before its detection.
PEMBUATAN DAN PENGUJIAN PROTOTIPE DESALINASI BERTENAGA SURYA YANG DIKOMBINASIKAN DENGAN LAMPU ULTRAVIOLET DAN SISTEM OTOMATIS BERBASIS MIKROKONTROLER Rosyad, Muhammad Sabilul; Marhaendrajaya, Indras; Sutanto, Heri
BERKALA FISIKA Vol 27, No 1 (2024): Berkala Fisika
Publisher : BERKALA FISIKA

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

Abstract

The lack of availability of clean water quantitatively is due to 97% of the water on earth is sea water, with a salt content of seawater of around 35000 mg/L causing the water to be unable to be used directly without prior treatment. One of the efforts that can be done to overcome the clean water crisis is through seawater desalination to produce water with low salinity. Several desalination methods that have existed are MSF (Multi Stage Flash Distillation) and Reverse Osmosis. But both of these methods have a high cost. Therefore, we need a method that is cheaper and easier to implement such as distillation. In this research, seawater desalination process uses the distillation method combined with a vacuum pump, electric stove and ultraviolet lamp. The use of a vacuum pump in the distillation system can speed up the evaporation process of seawater. Ultraviolet lamps function to degrade heavy metal pollutants and remove harmful bacteria. To maximize the performance of the tool, an electric stove with an automation system is added with solar panels as its energy source. Analysis of the tests carried out included the construction of the prototype, characterization and calibration of the LDR (Light Dependent Resistor) sensor and Arduino UNO microcontroller, total energy production and use, water production speed, and water quality. The results obtained include a prototype of seawater desalination. The characterization and calibration of the sensor in the automated system that the LDR sensor is running accurately, together with the Arduino UNO microcontroller, the LDR sensor can be an automation system that can make the prototype turn on and off automatically. The use of ultraviolet lamps shows that ultraviolet lamps have a photon energy of 3.0 eV and are able to work in visible light. The use of solar panels as an energy source can make an energy efficient prototype. This tool technology can increase water productivity up to 2 times and water quality shows a decrease in several pollutant parameters in distilled water including TDS (Total Dissolve Solid) of 99.7%, electrical conductivity of 99.987%, salinity of 99.93% , total coliform was 100%, and heavy metals Pb was 82.47%, Cd was 60.33%, Cu was 100%, Fe was 96.1%, Cr was 90.33%, and Zn was 98.9% , and the pH of seawater became neutral from 7.5 to 6.9. This prototype technology has the potential to be applied to the community.
Co-Authors Agung Cahyono Agus Subagio Ahmad, Harisma Zaini Annisa Fadillah Anugrah Rahma Ari Wiganti Arinar Rosyidah Eko Hidayanto Eko Sugiyanto Evi Setiawati Hadi Endrawati Hari Wibowo Heri Sutanto Hermin Pancasakti Kusumaningrum Imam Misbach Istianah Istianah K. Sofjan Firdausi K. Sofjan Firduasi Kristantyo Sukarsono Muhammad Iskandar Zulkarnain Muhammad Zainuri Pandji Triadyaksa Pandji Triadyaksa Priyono Priyono Rahmadi Setyawan Respita Sulistyo Riyani Riyani Robertus Triaji Mahendrajaya Rosyad, Muhammad Sabilul Setyaningsih , Agustina Sulistyo Sulistyo Sulung Edy Nugroho Teguh Tarsito Vincensius Gunawan S.K. Wahyu Dewi Utari Haryanti Widianingsih Widianingsih Yuvita Muliastuti Zaenal Arifin