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Spektra: Jurnal Fisika dan Aplikasinya
ISSN : 25413384     EISSN : 25413392     DOI : -
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Articles 193 Documents
INTERNET OF THINGS OF ELECTRONIC SEAL BASE ON GPRS SHORT MESSAGE SERVICE AND THINGSPEAK Syahwir, Irawati Dewi; Samsi, Agus; Firmansyah, Vera; Yunanto, Prasetyo Wibowo; Maheswara, Renanda; Anggraeni, Navieda Putri
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 3 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 3, December 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.043.03

Abstract

The field of metrology is mainly legal metrology; seals are closely related to the guarantee or validity of a measuring instrument. Seals are designed so that it is not easy for other parties to open the seal. Seal damage must be identified as soon as possible. The application of the Internet of Things (IoT) is needed in the process of sending data in real-time. IoT technology can be applied to electronic seals to know and record the condition of the measuring device. Broken seals caused by irresponsible parties can cause losses to consumers and owners of measuring instruments. Electronic seals are expected to be able to detect seal damage caused by abuse of authority or fraud. The broken seal will send data to the server as well as SMS (Short Message Service) to the related party. Electronic seals can send damage data via SMS within 20 seconds with a success rate of 92% and sending data through the ThingSpeak web server within 40 seconds with a success rate of 82%.
UTILIZATION OF COAL BOTTOM ASH AS BRIQUETTE MATERIAL Haryanti, Ninis Hadi; Suryajaya, Suryajaya; Wardhana, Henry; Noor, Rijali
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 3 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 3, December 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.043.02

Abstract

Research has been carried out on the use of coal bottom ash as a material for making briquettes as an alternative fuel. Carbonized of rubber seed shells and Halaban wood were used as mixtures and tapioca flour as adhesives. The composition used in making Halaban wood charcoal and coal bottom ash briquettes is 100% : 0%, 90% : 10%, 80% : 20%, and 70% : 30%. Tapioca flour used was as much as 5%, the pressure of 150 kg/cm2 and the size of 250 meshes. While for rubber seed shell and coal bottom ash briquettes, the composition used was with ratio 60% : 40% and 70% : 30%, the pressure used was 100, 150, and 200 kg/cm2 and the size of 50 meshes. Tapioca flour used was as much as 5%. The results of the characterization of rubber seed shell and coal bottom ash briquettes were water content (4.35 - 10.65)%, ash content (12.53 - 17.26)%, and calorific value (3597.59 - 4549.88) cal/g. While the characterization results of Halaban wood charcoal and coal bottom ash briquettes were water content (2.947 ? 4.097)%, ash content (0.383 ? 26.667)%, and calorific value (4749-6621) cal/g. The results showed that if coal bottom ash in the composition were higher, it would increase the water content and ash content of the briquettes, while the calorific value would be lower. The recommended composition of coal bottom ash was about 10-20 %. While if the briquettes pressure was higher, the water content, ash content and calorific value would be smaller. The recommended pressure was 150 kg /cm2.
ANALYSIS OF STRUCTURE AND ANTIMICROBIAL ACTIVITY OF CEO2 AND ND2O3 NANOPARTICLES Yuliani, Hanif; Mayasari, Rina Dewi; Kalembang, Eryanti; Deni, Yelvia; Santi, Defi Rahma; Pangestika, Putri Widya; Purwanto, Setyo; Sugeng, Bambang; Suyanti, Suyanti; Setyadji, Moch.
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 3 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 3, December 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.043.01

Abstract

Cerium oxide (CeO2) and Neodymium oxide (Nd2O3) nanoparticles using local content have been synthesized by precipitation method. The CeO2 and Nd2O3 nanoparticles were characterized by X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) to analyze the material phase and structure. The XRD spectrum shows that CeO2 and Nd2O3 nanoparticles have face-centered cubic and hexagonal, and cubic, respectively. The anti-microbial activity of CeO2 and Nd2O3 nanoparticles was analyzed by diffusion method using gram-negative bacteria (E. coli, S. aureus, P. aeruginosa), and gram-positive bacteria (S. entericatyphi, L. monocyogenes), and fungus (C. albicans). The result confirms that CeO2 and Nd2O3 nanoparticles have the capability of microbial pathogen inhibition. The CeO2 nanoparticles have the effective activities of inhibition for the microbial of S. aureus and S. entericatyphi, whereas Nd2O3 nanoparticles can inhibit the microbial of P. aeruginosa, S. entericatyphi, and  L. monocyogenes.
BURIED WAVEGUIDE POLYMETHYLMETHACRYLATE MODELING FOR REFRACTIVE INDEX SENSOR APPLICATION USING FINITE ELEMENT METHOD Yulianti, Ian; Azka, Jauhar; Darma Putra, Ngurah Made; Astuti, Budi
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 3 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 3, December 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.043.04

Abstract

The purpose of this study is to obtain the optimum buried waveguide structure through modeling for refractive index sensor applications. The waveguide cladding material used as Polymethylmethacrylate (PMMA). The core cross-section size was 1 × 1 mm2. The simulation was carried out at a wavelength of 650 nm using the Finite Element Method (FEM). The parameter of the buried waveguide optimized in this model was the core refractive index and the thickness of the upper cladding to obtain a high propagation constant and good sensitivity to refractive index. Modeling was done for various core refractive index values ??varied in the range of 1.52 to 1.59, which are the refractive index of various types of polymers. To optimize the sensitivity, the thickness of the upper cladding was varied between 0.125mm to 0.5mm. Besides, a simulation was also carried out for a waveguide without an upper cladding. The results show that the optimum waveguide is a waveguide without upper cladding using polyester as core material with a refractive index value of 1.57 and a sensitivity of 4.9 × 10-10rad /m. RIU.
THE APPLICATION OF SHIFT METHOD USING MOVING LASER ON CANCER CASES IN HEAD AREA USING 3DCRT AND VMAT TECHNOLOGY Samsun, Samsun; Hero A, Nursama; Kurniawan, Rudi; Septiti, Agnes Dwika
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 3 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 3, December 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.043.05

Abstract

The accuracy of patient position is essential to achieve the purpose of radiotherapy. Therefore, before radiotherapy, the isocenter of the patient must be determined to find out the target location. Verification serves to determine the isocenter that shifts from the reference point on the CT simulator. This research was conducted using field observation method, comparing the results of the isocenter after verification with the isocenter on the moving laser. Eight (8) samples from primary data were taken. Shift data was obtained from the average value and standard deviation. The instrument used was a linear accelerator of clinic iX type and On-Board Imager. The results obtained were the average lateral coordinate point of 0.055 cm; at the longitudinal isocenter point of 0.10 cm; and at the vertical isocenter point of 0.053 cm. From this research, it was concluded that the average value o the isocenter shift was less than 0.3 cm. This method can be used because the shift does not exceed the tolerance limit.
FRONT MATTER SPEKTRA VOLUME 4 ISSUE 3 DECEMBER 2019 Spektra, Editor
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 3 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 3, December 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.04300

Abstract

DINAMIKA ORBIT ASTEROID 2012 DA14 PASCAPAPASAN DEKAT DENGAN BUMI Utama, Judhistira Aria; Dermawan, Budi; Hidayat, Taufiq; Fauzi, Umar
Spektra: Jurnal Fisika dan Aplikasinya Vol 16 No 1 (2015): SPEKTRA, Volume 16 Nomor 1, Juni 2015
Publisher : Program Studi Fisika Universitas Negeri Jakarta

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Abstract

Abstrak   Tidak berselang lama pascapenemuannya (23 Februari 2012) oleh Observatorio Astronómico de La Sagra, Spanyol, asteroid 2012 DA14 (367943 Duende) mengalami papasan dekat dengan Bumi pada 16 Februari 2013 silam di jarak kurang dari jarak satelit geostasioner. Pascapapasan dekatnya tersebut asteroid ini dikelompokkan ke dalam kelas Aten, yaitu kelompok asteroid dekat-Bumi (ADB) yang memiliki orbit memotong orbit planet Bumi dengan setengah sumbu panjang orbit kurang dari 1 satuan astronomi. Menggunakan paket integrator Mercury, dalam pekerjaan ini dihitung evolusi orbital asteroid pascapapasan dekatnya hingga 1000 tahun ke depan. Selama selang waktu integrasi yang dilakukan, didapati bahwa asteriod ini beberapa kali mengalami papasan dekat dengan planet Bumi, Venus, dan Bulan. Dalam kurun waktu tersebut, asteroid dan keenampuluh asteroid virtualnya tidak ada yang menjadi benda penumbuk untuk planet Bumi dan Venus maupun Bulan.         Abstract   Less than one year after its discovery on February 23, 2012 by the Observatorio Astronómico de La Sagra, Spain, asteroid 2012 DA14 (also known as 367943 Duende) passed above Earth’s surface closer than geosynchronous satellites on February 16, 2013. According to Minor Planet Center (MPC) the asteroid is catagorized as Aten class for now, group of Earth-crossing asteroids with semimajor axis smaller than 1 astronomical unit. We employ Mercury package, a software for doing N-body integrations, to calculate the orbital evolution of 2012 DA14 for 1,000 years of orbital integrations after its last close approach with Earth. According to variation of nominal and virtual asteroids’s orbital elements during the integration time, the objects will experience several times of close approach with Earth, Venus and Moon but will not to be an impactor for these Terrestrial planets and natural satellite.   Keywords: near-Earth asteroids, orbital evolution, Mercury integrator.
PEMODELAN 2D RESPON ANOMALI GAYA BERAT MIKRO ANTAR WAKTU AKIBAT AMBLESAN DAN DINAMIKA MUKA AIR TANAH Supriyadi, Supriyadi; Djuniadi, Djuniadi; Hardyanto, Wahyu
Spektra: Jurnal Fisika dan Aplikasinya Vol 16 No 1 (2015): SPEKTRA, Volume 16 Nomor 1, Juni 2015
Publisher : Program Studi Fisika Universitas Negeri Jakarta

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Abstract

Abstrak   Metode Gaya berat mikro antar waktu merupakan pengembangan dari metode Gaya berat dengan ciri khas berupa pengukuran ulang gaya berat di titik yang sama pada selang periode tertentu, misalnya 6 bulan. Problem utama pada survei gaya berat mikro antar waktu  adalah  bahwa sumber anomali gaya berat mikro antar waktu terdiri atas dua sumber, yaitu amblesan dan perubahan densitas bawah permukaan yang berhubungan dengan dinamika  air tanah yang berupa kenaikan atau penurunan muka air tanah. Berdasarkan kondisi tersebut, maka dilakukan pemodelan 2 D respon anomali gaya berat mikro antar waktu dengan menggunakan perangkat lunak Grav 2D. Sebagai contoh digunakan kasus Semarang bagian utara. Parameter model disesuaikan dengan kondisi lapangan yang berupa densitas lapisan, besar amblesan berdasarkan hasil penelitian terkait  dengan asumsi telah terjadi amblesan dan penurunan muka air tanah atau kenaikan muka air tanah. Hasil pemodelan menunjukkan bahwa untuk (1) amblesan 10 cm, penurunan muka air tanah 1, 5 m dengan dimensi amblesan lebih kecil dari penurunan muka air tanah dengan 3 kedudukan yang berbeda memberikan anomali sebesar 12,196 mGal, 30,706 mGal dan  13,376 mGal. (2) dimensi amblesan dan kenaikan muka air tanah sama besar memberikan anomali sebesar 63,546 mGal, dan (3) dimensi amblesan lebih besar dari penurunan muka air tanah memberikan anomali sebesar 30,856 mGal. Berdasarkan analisis FFT (Fast Fourier Transform) dapat disimpulkan bahwa untuk memisahkan frekuensi anomali gayaberat akibat amblesan dan perubahan  kedalaman muka air tanah diperlukan syarat dimensi kedua sumber anomali berbeda. Untuk kasus dimensi kedua sumber anomali sama, maka anomali gayaberat akibat amblesan dan penurunan muka air tanah tidak dapat dipisahkan.   Abstract   Microgravity method is the development of Gravity methods with the typical form of repeated measurements at the same point at the interval specified period, such as six months. The main problem in micro-gravity surveys over time is that the source of time lapse micro gravity anomaly  consisted of two sources, namely subsidence and subsurface density changes associated with groundwater dynamics in the form of an increase or decrease in ground water level. Under these conditions, then do modeling 2 D response time lapse micro gravity anomaly using Grav2D software. For example use case of the northern part of Semarang. Model parameters adjusted to the field conditions such as density layer, a large subsidence based on research results associated with the assumption that there has been a subsidence and groundwater level decline or rise in groundwater level. Modeling results show that for (1) subsidence 10 cm, decrease in groundwater level 1, 5 m with dimensions smaller subsidence of groundwater level decline by 3 different positions gives  anomaly of 12.196, 30.706 and 13.376 mGal, (2) the dimensions of subsidence and groundwater level rise as great give anomaly at 63.546 mGal, and (3) subsidence dimension greater than the  decrease in groundwater level giving anomalies of 30.856 mGal Based on the analysis of FFT (Fast Fourier Transform) can be inferred that to separate frequency gravity anomaly due to subsidence and groundwater depth changes necessary requirement a second dimension different sources of anomalies. For the case of the second dimension of the same anomaly source, then the gravity anomaly due to subsidence and subsidence of groundwater can not be separated.   Keywords: microgravity, time lapse, groundwater
ANALISIS VARIASI SPASIOTEMPORAL PANAS LATEN KONDENSASI HIDROMETEOR BENUA MARITIM INDONESIA BERBASIS ESTIMASI SATELIT DAN LUARAN MODEL Krismianto, Krismianto; Adikusumah, Nurzaman; Suryantoro, Arief
Spektra: Jurnal Fisika dan Aplikasinya Vol 16 No 1 (2015): SPEKTRA, Volume 16 Nomor 1, Juni 2015
Publisher : Program Studi Fisika Universitas Negeri Jakarta

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Abstract

Abstrak   Analisis variasi spasial dan temporal panas laten kondensasi hidrometeor Benua Maritim Indonesia (BMI) berbasis estimasi satelit dan luaran model dibahas dalam makalah ini. Tujuan penelitian ini adalah untuk memahami karakteristik dan mekanisme hujan di BMI, terutama pada hal sebaran horizontal panas laten kondensasi hidrometeor BMI dan profil vertikal parameter tersebut di atas tiga wilayah Bandara Indonesia (Bandung, Padang dan Ambon). Pemilihan ke tiga wilayah ini sekaligus menunjukkan adanya tiga pola utama curah hujan yang ada di Indonesia, yang dikenal sebagai pola hujan monsunal (Bandung), ekuatorial (Padang) dan lokal (Ambon). Hasil yang diperoleh menunjukkan bahwa berdasar estimasi satelit, secara spasial wilayah Indonesia yang berada di sekitar garis khatulistiwa (5 °LU – 5 °LS) secara bercak (spotty) merupakan wilayah dengan intensitas panas laten kondensasi hidrometeor yang tinggi pada perioda Desember 1998, Januari – Februari 1999 dengan intensitas antara 0,60 – 0,80 K/jam yang terjadi di ketinggian 6 – 8 km. Hal analog, pada perioda Juni, Juli, Agustus 1999 terjadi di wilayah yang berada di utara Indonesia (5 °LU – 25 °LU) dengan nilai antara 0,30 – 0,45 K/jam. Variasi spasial dan temporal panas laten kondensasi hidrometeor berdasar luaran model menunjukkan adanya pola (cakupan luasan) dan nilai yang berbeda dari estimasi satelit tersebut.   Kata kunci : panas laten kondensasi hidrometeor, satelit dan model   Abstract   Analysis of spatial and temporal variations of latent heat of condensation hydrometeor Indonesian Maritime Continent (IMC) based on satellite estimation and models outcomes are discussed in this paper. The purpose of this research is to understand the characteristics and mechanisms of rain in IMC regions, especially in terms of horizontal distribution of latent heat of condensation hydrometeor of IMC areas and profile parameters vertical aforementioned three regions Airports Indonesia (Bandung, Padang and Ambon). Election to these three areas also indicates three main patterns of rainfall in Indonesia, known as monsoonal pattern (Bandung), equatorial (Padang) and local (Ambon). The results obtained indicate that the satellite estimations, spatially Indonesian territory located around the equator (5 °N - 5 °S) by spotting is a region with the intensity of the latent heat of condensation hydrometeor high in the period December 1998, January - February 1999 with an intensity of between 0.60 to 0.80 K / h which occurred at an altitude of 6-8 km. It analogue, in the period June, July, August 1999 occurred in the region located in northern Indonesia (5 °N - 25 °N) with values ​​between 0.30 to 0.45 K / h. Spatial and temporal variations of latent heat of condensation hydrometeor based on models outcomes indicate a pattern (coverage area) and different values from satellite estimations.   Keywords: latent heat of condensation hydrometeor, satellite and model
PENGARUH POSISI INTRUDER TERHADAP BENTUK PERMUKAAN BED GRANULAR PADA EFEK KACANG BRASIL DUA-DIMENSI Viridi, Sparisoma; Khotimah, Siti Nurul; Wibowo, Hari Anggit Cahyo; Ain, Trise Nurul; Aji, Dimas Praja Purwa
Spektra: Jurnal Fisika dan Aplikasinya Vol 16 No 1 (2015): SPEKTRA, Volume 16 Nomor 1, Juni 2015
Publisher : Program Studi Fisika Universitas Negeri Jakarta

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Abstrak   Efek kacang Brasil dua-dimensi dengan partikel bed dan intruder terbuat dari keping akrilik diamati dengan vibrasi sinusoidal yang diselingi waktu diam sehingga memudahkan untuk mengambil foto yang baik untuk diproses lebih lanjut. Parameter vibrasi adalah f = 13 Hz dan Γ = 2. Dalam tulisan ini disajikan evolusi posisi intruder dengan waktu apung Trise = 67 langkah, dengan posisi awal intruder saat sisi bawahnya mengenai dasar wadah dan posisi akhir saat sisi atasnya menyentuh permukaan bed partikel. Tinggi bed partikel awal adalah 21 buah dan lebarnya adalah 19 buah. Rasio intruder dan bed kira-kira 2.545. Bentuk permukaan bed paling melengkung diamat saat posisi intruder berada di antara konfigurasi awal dan akhir dalam observasi.   Abstract   Two-dimension Brazil-nut effect using acrylic plate as intruder and bed particles is observed under non-continuous sinusoidal vibration in order to obtain sufficient image quality for further process. Vibration parameters are f = 13 Hz and Γ = 2. In this work time series of intruder position is presented, which shows that it has rise time Trise = 67 steps, with initial position defined as lower side of intruder in touch with bottom of the container and final position is defined as upper side of intruder is on the bed particle surface. Initial height and width of bed particles are 21 and 92 particles, respectively. Ratio of intruder and bed particle diameter is about 2.545. Most curved of bed particle surface is observed while intruder position is about in the middle between its initial and final configurations.   Keywords: Brazil-nut effect, granular materials, two-dimension system, vertical vibration, rise time.

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