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BERKALA FISIKA
Published by Universitas Diponegoro
ISSN : -     EISSN : -     DOI : -
Core Subject : Science,
Physics
BERKALA FISIKA adalah jurnal saintifik yang diterbitkan secara periodik 3 bulanan. Jurnal ini memuat kajian-kajian Fisika baik kajian teoretik maupun hasil eksperimen. Jurnal ini juga memberi ruang yang luas bagi kajian – kajian aplikasi fisika dalam bidang teknologi, ilmu-ilmu hayati dan kedokteran.
Arjuna Subject : -
Articles 369 Documents
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PENGUKURAN COMPUTED TOMOGRAPHY DOSE INDEX (CTDI) PADA FANTOM KEPALA DENGAN MENGGUNAKAN CT DOSE PROFILER Ahadiyah, Naeli Ni'matin; Setiawati, Evi; Arifin, Zaenal; Anam, Choirul
BERKALA FISIKA Vol 23, No 4 (2020): Berkala Fisika
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This study aims to  measure  computed  tomography  dose  index (CTDI) on  a  head  polymethyl methacrylate (PMMA) phantom using a CT dose profiler for various slice thicknesses. The slice thicknesses were 3, 5, and 10 mm. Dose measurements were performed in spiral mode for every hole  within  the  head  PMMA  phantom.  A  CT  dose  profile  analyzer  software  integrated  the profile  dose  along  100  cm  to  find  the  CTDI100.  The  CTDIw  was  calculated  as 1/3×(CTDI100,center)+2/3×(average CTDI100, perifer). Since the pitch was unity, the CTDIvol was similar to the CTDIw. The values of CTDIvol for slice thickness variations were from 45.7 mGy to 46.0 mGy.  This result indicated that there is no significant different of CTDIvol measured using CT dose profiler for slice thicknesses from 3 mm up to 10 mm.Keywords: CT dose profiler, CTDI, CTDI100, CTDIw, CTDIvol, slice thickness 
PENGARUH FAKTOR EKSPOSI DAN TEBAL FANTOM TERHADAP MEAN GLANDULAR DOSE (MGD) PADA PESAWAT SINAR-X MAMMOGRAFI Rauf, Resmy Aulyah; Astuty, Sri Dewi; Dewang, Syamsir; Mulyadin, Mulyadin
BERKALA FISIKA Vol 23, No 3 (2020): Berkala Fisika
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One of the applications of X rays in diagnostic radiology is mammography. The mammography is  used  for  detecting  abnormalities  in  the  breast  tissue  early  with  the  ability  to  detect microcalcification  (<5  mm).  Unlike  the  conventional  X-ray  and  CT  scanner,  the  clinical mammography  uses  a  low  voltage  <35  kVp,  because  the  properties  of  the  breast  tissue structures are soft and thin. Although the tube voltage source is relatively low, in clinical use, the absorbed dose by patients in the form of mean glandular dose (MGD) must  be lower than the  value  standards  had  been  established  by  the  Nuclear  Energy  Supervisory  Agency (BAPETEN) No.2, 2018, i.e <3 mGy. This study aims to evaluate the effect of variations in the values of the tube voltage, the current-time, and the thickness of the polymethyl-methacrylate (PMMA) phantom on the calculation results of the MGD values. The results obtained showed that  the  mean  MGD  values  for  the  4,5  cm  of  the  phantom  thickness  were  0.077, 0.087,  and 0.093  mGy  (at  4.5  mAs)  and  0.171,  0.194,  and  0.207  mGy  (at  10  mAs),  while  for  the  6  cm phantom thickness obtained 0.103, 0.117, and 0.124 mGy (at 4.5 mAs) and 0.228, 0.259, and 0.276 (at 10 mAs) for all the data to 27, 28, and 29 kVp of tube voltage, respectively. All of the MGD values obtained about between 0.077-0.276 mGy are <3 mGy or still under BAPETEN standards.Keywords: mammography, MGD value, PMMA phantom 
ELECTRIC FIELD CONTOURS IN NON-UNIFORM ELECTRODE SHAPE Umiati, Ngurah Ayu Ketut; Facta, Mochammad
BERKALA FISIKA Vol 23, No 4 (2020): Berkala Fisika
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Silent discharge is well known method to initiate plasma reaction because initial  discharge is easily triggered by implementing high voltage to the pair of coupled electrodes with a distance. However,  it  is  very  difficult  to  determine  the  exact  amount  of  the  voltage  that  initiates  the discharge.  There  are  many  factors  influence  the  condition  of  initial  discharge  such  as dimensions,  type  and  geometrical  shapes  of  electrode,  thickness  of  insulation,  and  type  of electric field inside the gap between the electrodes. To obtain lower initial discharge voltage, it is urgent to find the best electrode shape producing electric field contours in line with electron emission triggering. This work examines the behavior of electric field and the applied voltage surrounding  electrodes  by  investigating  the  mathematical  expression  for  given  voltage  and generated  electric  field.  The  mathematical  relationship  then  gives  a  basis  of  theoretical background for electric field contours of two shape electrodes. It is also well known that among many electrodes, the non-uniform geometrical shape is preferred to initiate electric field easily. In this study, a hole shape and a bulge type electrode are investigated.Keywords: silent discharge, electric field, differential equation, electrode shape 
SISTEM PENYIRAM TANAMAN CABAI OTOMATIS UNTUK MENJAGA KELEMBABAN TANAH BERBASIS ESP8266 Priyono, Andi; Triadyaksa, Pandji
BERKALA FISIKA Vol 23, No 3 (2020): Berkala Fisika
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Abstract

The process of planting certain plants requires extra attention, especially in maintaining soil moisture such as in chili plants. Therefore, this research develops an automatic plant watering system that can be monitored via a smartphone using the Telegram application. This system can  do  automatic  watering  according  to  soil  moisture  and  measures  the  temperature  and humidity of the surrounding environment controlled by ESP8266 which is equipped with 16x2 LCD,  YL-69  sensor,  and  DHT11  sensor.  Watering  system  trials  show  excellent  readability comparable  to  calibrators.  Temperature,  humidity,  and  soil  moisture  are  informed  via  a smartphone and LCD that are attached to the watering prototype. The Telegram application is able to send information to carry out the function of watering automation when the soil moisture is less than 50% as a reference in accordance with the characteristics of the chili plants. In addition, the automatic sprinkler trial via the Telegram command, as desired by the user, was also successfully carried out. It is concluded that development of a plant watering system based on soil moisture information has been successfully carried out. The system shows the ability of the Telegram application to provide remote commands to the system that works.Keywords:  Automatic  plant  watering  system,  ESP8266,  Sensor  YL-69,  Sensor  DHT11,  Chili  plants, Telegram
RANCANG BANGUN SISTEM PENGAMBILAN CITRA DAN PENGATUR POSISI JARAK OBYEK PADA MIKROSKOP DIGITAL MENGGUNAKAN JARINGAN WiFi SMARTPHONE ANDROID BERBASIS RASPBERRY Pi 3 DAN MIKROKONTROLER ESP32 Putranto, Ari Bawono; Baital, Muhammad Sawal; Muhlisin, Zaenul; Adi, Kusworo
BERKALA FISIKA Vol 23, No 4 (2020): Berkala Fisika
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In  this  study,  the  ESP32  microcontroller  and  the  Raspberry  Pi  have  been  successfully combined  to  adjust  the  position  of  the  digital  microscope  object  and  take  images  using  an android smartphone-based application via a WiFi network. The working method of adjusting the position of the microscope object is done by using the number of steps on a unipolar stepper motor  starting  from  the  farthest  distance  to  the  digital  microscope  objective  lens  which  is regulated by the ESP 32 microcontroller. Meanwhile, viewing the microscope object directly can  be  done  via  a  mobile  screen  connected  to  a  WiFi  network  to  a  digital  microscope  USB camera that has been converted into an IP camera by the Raspberry Pi. Therefore, through the use of a digital microscope application with an Android smartphone, it will be easier to obtain a sample image of a digital microscope object when conducting experiments in the laboratory.Keywords: Digital Microscope, Android Smartphone, WiFi, Rsabperry Pi, Microcontroller ESP 32
ANALISA KERENTANAN TANAH DI KECAMATAN ADIPALA KABUPATEN CILACAP MENGGUNAKAN METODE MIKROTREMOR SEBAGAI UPAYA MITIGASI BENCANA GEMPA BUMI Wachidah, Siti Fauzatun; Agustin, Ninik
BERKALA FISIKA Vol 24, No 1 (2021): Berkala Fisika
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Telah dilakukan penelitian tentang kerentanan tanah di Kecamatan Adipala, Kabupaten Cilacap, menggunakan  data  rekaman  mikrotremor  untuk  dianalisa  menggunakan  metode  Horizontal  to vertical Spectral Ratio (HVSR). Metode ini digunakan untuk mengetahui nilai frekuensi dominan tanah  (f0)  dan  amplitudo  dari  frekuensi  dominan  tersebut  (A0).  Nilai  f0  dan  A0  yang  diperoleh selanjutnya akan digunakan lagi untuk menghitung nilai kerentanan tanah (Kg) yang berkaitan dengan kemampuan atau ketahanan tanah terhadap gempa. Dari hasil penelitian yang mengambil 17 titik pengambilan data diperoleh bahwa Kecamatan Adipala memiliki nilai amplifikasi tanah antara 1-8 dan merupakan kawasan dengan resiko kerusakan tinggi apabila terjadi gempa.
IMPLEMENTASI METODE CONTRAST LIMITED ADAPTIVE HISTOGRAM EQUALIZATION DAN LAPLACIAN OF GAUSSIAN FILTER UNTUK PENINGKATAN KONTRAS CITRA CT Awwalin, Aufi Rizqiatul; Setiawati, Evi; Anam, Choirul
BERKALA FISIKA Vol 24, No 1 (2021): Berkala Fisika
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The  image  obtained  from  the  CT  scanner  has  a  relatively  low  contrast.  Image  contrast  can  be enhanced  by  using  an  algorithm  of  contrast  limited  adaptive  histogram  equalization  (CLAHE). However, the implementation of CLAHE causes an increase  of noise. Furthermore, noise can be reduced  using  a  noise  reduction  filter,  but  it  reduces  the  spatial  resolution  of  the  image.  This study proposed a combination of the CLAHE method and the Laplacian of Gaussian (LoG) filter noise reduction algorithm to obtain images with high contrast,  while maintaining the  noise and spatial  resolution.  In  this  study,  27  abdominal  CT  images  and  MTF  phantom  CT  images  were investigated using our proposed method. As a comparison, this study also evaluated the results of combination  of  CLAHE  and  Gaussian  filters.  Evaluation  of  the  results  of  image  quality improvement  was carried out qualitatively (visually) and quantitatively by calculating the mean squared  error  (MSE),  peak-signal  to  noise  ratio  (PSNR)  and  spatial  resolution  using  a modulation transfer function (MTF) of 10%. The results of this study qualitatively (visually) and quantitatively showed that the combination of CLAHE and LoG filters produces images with high contrast,  while  maintaining the  noise  and  the  spatial  resolution  of  the  image.  Compared  to  the combination of  CLAHE and Gaussian filters or CLAHE alone,  the  combination of CLAHE and Log  filters  provides less  noise  and  higher  spatial  resolution.  Thus,  combination  of  CLAHE  and LoG filters can be used as an alternative algorithm to increase the contrast in CT images.
PENGARUH ENERGI AKTIVASI TERHADAP AKTIVITAS NANOPARTIKEL ZnFe2O4 PADA ADVANCED OXIDATION PROCESSES (AOPs) SEBAGAI PENGURAI RHODAMINE B Kadarisman, Kadarisman; Nurhasanah, Iis
BERKALA FISIKA Vol 24, No 1 (2021): Berkala Fisika
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Advanced  Oxidation  Processes  (AOPs)  is  one  of  the  methods  used  to  treat  organic  dye  waste. Powder-based  AOPs  as  photocatalyst  have  disadvantages  due  to  surface  adsorption  and agglomeration, thereby reducing the percentage of dye decomposition. In this study, the addition of  chemical  energy  (photo-Fenton-like)  and  ultrasonic  waves  (sono-photocatalyst)  in  the photocatalyst process was used to increase the activity of powder-based photocatalyst material as a  decomposer  of  Rhodamine  B  organic  dye.  The  photocatalyst  material  used  was  ZnFe2O4 nanoparticles synthesized using precipitation method with a calcination temperature of 700oC for 3 hours. The combination of light energy (4.69 eV) and chemical energy (44 meV) in the photo- Fenton-like process showed the highest percentage of Rhodamine B decomposition (70%). The use of  ultrasonic  energy  (28  meV)  in  the  sono-photocatalyst  process  increases  the  rate  of decomposition  of  RhB  by  2  times.  The  addition  of  chemical  energy  (44  meV)  increased  the photocatalyst activity of ZnFe2O4 nanoparticles on decomposition of RhB by 8 times. The results showed that the addition of chemical energy to the photocatalyst  activity of ZnFe2O4 was much more efficient than the addition of ultrasonic energy.
RANCANG BANGUN SISTEM KENDALI SUHU DAN KELEMBABAN DARI MINI GARDEN BUNGA KRISAN MENGGUNAKAN SMARTPHONE BERBASIS MIKROKONTROLER Dananjaya, Bachtiar Putra; Sumariyah, Sumariyah
BERKALA FISIKA Vol 24, No 1 (2021): Berkala Fisika
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The  temperature  and  humidity  control  system  of  the  Krisan  Flower  Mini  Garden  has  been designed and implemented. The main components of this control systems were the NodeMCU 8266 microcontroller and smartphones that communicate using the internet of things (IoT). The system support components include the DHT 11 sensor module as a temperature and humidity sensor,  real time clock (RTC) module, liquid crystal display  (LCD) as a result viewer, relay board  module  and  pump.  The  microcontroller  read  and  processed  the  temperature  and humidity sensor output data in the form of a digital voltage signal. The measurement data were displayed on the LCD with an LED indicator and sent to the Telegram application. If the sensor output did not meet the needs of the Chrysanthemum flower, the microcontroller turned on the actuator to turn on the water pump and lights as irradiation. The system test was carried out in the Chrysanthemum Mini Garden by comparing the LCD reading with standard tools. The test results show a difference in temperature of about 0.2-3 oC and humidity of about 1-7%.
PEMBUATAN DAN KARAKTERISASI ARANG AKTIF IJUK POHON AREN (Arenga Pinnata) SEBAGAI MEDIA FILTRASI DESALINASI AIR PAYAU Teke, Sosiawati; Dewi, Wa Ode Nanang Trisna; Jali, Wa; Yumnawati, Yumnawati
BERKALA FISIKA Vol 24, No 1 (2021): Berkala Fisika
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Abstract

Salah  satu  masalah  yang  dihadapi  masyarakat  pesisir  adalah  kurangnya  ketersediaan  air bersih.    Masyarakat  pesisir  memanfaatkan  air  sumur  gali,  air  laut  dan  air  payau.  untuk memenuhi kebutuhan air bersih. Mengkonsumsi air dengan kadar garam yang lebih banyak dari  air  tawar  dalam  jangka  panjang  dapat  berdampak  buruk  bagi  kesehatan,  sehingga diperlukan metode pengolahan air payau menjadi air tawar yang murah dan mudah  salah satunya  dengan  pemanfaatan  arang  aktif.  Arang  aktif ijuk  pohon  aren  diharapkan  mampu menurunkan kadar salinitas dalam air payau dan dapat membantu masyarakat pesisir untuk memperoleh kualitas air yang memenuhi standar parameter kualitas air bersih.  Ijuk pohon aren  dikarbonasi  dengan  metode  pirolisis  pada  suhu  450oC  selama  15  menit  dan  aktifasi menggunakan  pemanas  microwave  dengan  daya  300  Watt,  selama  4,  5,  6  dan  7  menit. Karakterisasi  arang  aktif  menggunakan  SEM,  menunjukan  bahwa  waktu  aktifasi mempengaruhi jumlah dan luas permukaan pori dari arang ijuk pohon aren. Penambahan arang  aktif  selama  2  menit  ke  dalam  air  payau  dapat  menurunkan  salinitas  air  payau. Karbon  aktif  yang  teraktifasi  selama  7  menit  diaplikasikan  pada  media  filtrasi  air  payau dan diperoleh penurunan salinitas air payau. Berdasarkan percobaan yang telah dilakukan bahwa  waktu  aktifasi  mempengaruhi  jumlah  dan  luas  permukaan  pori  arang  ijuk  pohon aren  dan  arang  ijuk  pohon  aren  teraktifasi  dapat  menurunkan  kadar  salinitas  pada  air payau.

Page 33 of 37 | Total Record : 369

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