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Spektra: Jurnal Fisika dan Aplikasinya

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Published by Universitas Negeri Jakarta

ISSN : 25413384 EISSN : 25413392 DOI : -

Core Subject : Science, Engineering,

Aerospace Engineering Electrical & Electronics Engineering Energy Materials Science & Nanotechnology Physics

Arjuna Subject : -

Articles 260 Documents

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TWO-DIMENSIONAL DYNAMICS OF SPHERICAL GRAIN FLOATING ON THE PROPAGATING WAVE FLUID SURFACE Sparisoma Viridi; Nurhayati Nurhayati; Johri Sabaryati; Dewi Muliyati
Spektra: Jurnal Fisika dan Aplikasinya Vol 3 No 3 (2018): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 3 Issue 3, December 2018
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Abstract Simulation of a spherical grain floating in fluid surface propagating sinusoidal wave is performed using molecular dynamics method by assuming that superposition of buoyant, gravitational, and viscous forces will make the grain to move in two-dimension. It is different than previous result, where the grain can only move in one-dimension since size of the grain Db << Î»f. In this work Db < Î»f so that direction of buoyant force must be considered. It is predicted theoretically that the two-dimensional motion tends to be a one-dimensional motion when Db/Î» less than a certain value, but it remains as a two-dimensional motion when more than that value. In 20 s of observation frequency of the sinusoidal wave can determine whether the grain will move in the same direction of the travelling wave or not. Keywords: grains, simulation, buoyant force, gravitational force, viscous force.

MODEL PEMBANGKIT LISTRIK TENAGA PANAS BUMI SISTEM HYBRID FLASH-BINARY DENGAN MEMANFAATKAN PANAS TERBUANG DARI BRINE HASIL FLASHING Muhamad Ridwan Hamdani; Cukup Mulyana; Renie Adinda Pitalokha; Fajar Muhammad
Spektra: Jurnal Fisika dan Aplikasinya Vol 1 No 2 (2016): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 1 Nomor 2, Desember 2016
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Abstrak Potensi panas bumi di Indonesia sangat melimpah, yaitu terdapat 256 prospek dengan potensi sekitar 28.617 MW. Sumber panas bumi di Indonesia merupakan sumber dengan sistem hydrothermal yang didominasi oleh jenis dominasi air, dengan karakteristik sekitar 20% uap dan 80% air. Jenis pembangkit di Indonesia yang digunakan untuk memanfaatkan sumber dominasi air ini adalah sistem single-flash. Brine hasil flashing dari sistem ini masih memiliki temperatur yang tinggi sehingga masih bisa digunakan sebagai sumber energi baru, yaitu dengan diflash ulang maupun digunakan sebagai sumber pemanas pada sistem binary cycle. Oleh karena itu, dibuatlah model pembangkit listrik tenaga panas bumi sistem hybrid flash-binary untuk memanfaatkan brine hasil flashing sehingga diperoleh daya yang lebih besar. Pada penelitian ini digunakan software HYSYS 7.0 dalam pembuatan modelnya dan dibuktikan dengan perhitungan termodinamik pada setiap bagiannya. Pada penelitian ini telah dibuat model pembangkit listrik tenaga panas bumi yang menghasilkan total daya 279,178 MW dan penambahan daya 32,91% tanpa harus membuat sumur produksi baru. Kata-kata kunci: flashing, binary cycle, HYSYS 7.0, hybrid flash-binary Abstract Indonesia has a great number of geothermal sources, there are 256 prospects with 28,617MW potential power. The sources is dominated by hydrothermal system that usually has 20% vapor and 80% liquid. The power plant that appropriate to used is single-flash system. In this system, the brine which has a great number of enthalpy is reinjected to reservoir. This research was performed to design the hybrid flash-binary system power plant model by utilizing the wasted brine to gain the greater power. HYSYS 7.0 was used to made the model and based on the fundamental thermodynamic principles energy and mass conservation calculation in every single part of the plant. The hybrid flash-binary system model was made and resulted additional power 32.91% with 279.178MW total power without drilling the new production well. Keywords: flashing, binary cycle, hybrid flash-binary, HYSYS 7.0

KARAKTERISRIK KRISTAL DAN OPTIK NANOPARTIKEL ZINC OXIDE: KAJIAN EFEK MOLARITAS DALAM PROSES HIDROTHERMAL Togar Saragi; Yonatan R Purba; Satria Auffa; Maria Oktaviani; Edward Simanjuntak; Tuti Susilawati; Norman Syakir; Mariah Kartawidjaja; Risdiana Risdiana; Ayi Bahtiar
Spektra: Jurnal Fisika dan Aplikasinya Vol 1 No 2 (2016): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 1 Nomor 2, Desember 2016
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Abstrak Sintesis nanopartikel Zinc Oxide (ZnO) dengan metode hidrothermal sangat dipengaruhi oleh beberapa parameter, salah satu diantaranya adalah perbandingan prekursor dan katalis dalam pelarut. Dalam penelitian ini telah berhasil disintesis nanopartikel zinc oxide dengan metode hidrothermal. Prekursor yang digunakan adalah zinc acetat dan katalis NaOH dalam pelarut ethanol. Perbandingan molaritas prekursor dan katalis adalah 0,008:0,5 dan 0,3:0,9. Karakteristik optik, morfologi dan struktur kristal nanopartikel ZnO masing-masing dilakukan dengan pengukuran UV-Vis, TEM dan XRD. Nanopartikel yang dihasilkan memiliki memiliki struktur kristal hexagonal wurtzite. Nanopartikel zinc oxide dengan perbandingan 0,3:0,9 memiliki karakteristik yang paling baik dibandingkan dengan nanopartikel dengan perbandingan 0,008:0,5. Reaksi dalam hidrothermal kaitannya dengan perubahan tekanan akibat peningkatan volume akan dikaji lebih jauh. Kata-kata kunci: oksidasi zinc, nanopartikel, hidrotermal, molaritas Abstract Synthesis of Zinc Oxide (ZnO) nanoparticles by hydrothermal method is influenced by several parameters one of them is the ratio of the precursor and catalyst in a solvent. In this study, we have successfully synthesized of zinc oxide nanoparticles by hydrothermal method. The raw material of precursor is zinc acetate, NaOH as catalyst and ethanol as a solvent. The molarity ratio of precursor and catalyst are 0.008: 0.5 and 0.3: 0.9. The optical characteristics, morphology and crystal structure of ZnO nanoparticles were characterised by the UV-Vis, TEM and XRD, respectively. From XRD measurement, it was observed that samples have hexagonal wurtzite structure and all peaks are well fitted with JCPDS:36-1451 data. The growth condition in the ratio of 0.3: 0.9 showed the best sample with high quality crystal structure and rod form. The effect of molar ratio to the characteristics of nanoparticle will be studied further in relation with the change of volume, and pressure inside of the reactor. Keywords: zinc oxide, nanoparticle, hidrotermal, molaritas

SIFAT MEKANIK BAHAN KOMPOSIT KAMPAS REM BERBAHAN DASAR SERBUK ARANG KULIT BUAH MAHONI Herwidhi Tri Prabowo; Sulhadi Sulhadi; Mahardika Prasetya Aji; Teguh Darsono
Spektra: Jurnal Fisika dan Aplikasinya Vol 2 No 2 (2017): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 2 Nomor 2, Agustus 2017
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Mahogany bark is one of natural material which not used optimally in society. The overabundance of mahogany bark appearing new problem of garbage which charges an alternative solution creatively and innovatively becomes a new efficient and effective product. An alternative solution of mahogany bark utilization is as organic composite material of disk brake. The making of organic composite material of brake disk firstly is reducing the mahogany bark becomes a homogeneous carbon powder. The mahogany bark was smoked being of carbon and mixed with coconut shell and resin polyester as an adhesive. The organic composite material was produced, tested by Brinell Hardness test and attrition test by varied of composition percentage. There are five kinds of composite material composition had been tested. The result is obtainable of the most precise composition percentage 60% mahogany bark carbon, 15% coconut shell carbon, and 25% resin polyester which has brinell hardness number and attrition massa identically with Standar Nasional Indonesia (SNI). Keywords: mahogany bark, composite material, disk brake, Brinell hardness test, attrition test

PEMANFAATAN DATA SATELIT HIMAWARI 8 UNTUK MENDETEKSI SEBARAN ASAP: STUDI KASUS DI KALIMANTAN DAN SUMATERA TANGGAL 8 DAN 9 SEPTEMBER 2015 Ayu Vista Wulandari; Ni Kadek Trisna Dewi; Wishnu Agum Swastiko
Spektra: Jurnal Fisika dan Aplikasinya Vol 2 No 2 (2017): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 2 Nomor 2, Agustus 2017
Publisher : Program Studi Fisika Universitas Negeri Jakarta

The forest fires that occurred in the entire month of September 2015 was quite considerably disturbing many public activities in Borneo and Sumatera. The smoke which is caused by forest fire has negative impact for the surrounding environments, one of them is reducing horizontal visibility. Meteorological stations in Borneo and Sumatra recorded the lowest visibility occurred on September, 8th and 9th 2015 at average range was 100 m. Based on information of BMKG (Indonesian Agency of Meteorological, Climatological and Geophysics) noted that during the month of September 2015 there was a distribution of hotspots which indicates the occurrence of forest fire cases. This research is aimed to determine the potential of distribution of smoke by satellite imagery of Himawari 8 to reduce its negative impacts. By using this method that is by comparing the hotspot distribution data from BMKG with false color RGB image product (1 visible channel and 2 near infrared channel) along with trajectory of smokeâ€™s distribution by utilizing application of GMSLPD SATAID. The distribution of smoke can be seen as an image with the brownish pattern which partially covered the area of Borneo and Sumatera. The result showed that the smokeâ€™s distribution by the result of RGB imagery well-matched enough with the hotspotâ€™s distribution data from BMKG, which the smoke almost covered most area of the western of Sumatera and center of Borneo. In this case also supported by the trajectory of smokeâ€™s distribution which is derived from southeast-south and spread to the northwest-north in the researches area. By using the observation data from chosen meteorological stations showed a similar result with the above method. Thus, it can be assumed that by using satellite imagery of Himawari 8 is quite capable to discover smokeâ€™s distribution caused by forest fires case. Keywords: Smoke, Satellite, Himawari 8, SATAID.

FRONT MATTER SPEKTRA VOLUME 1 NOMOR 1 AGUSTUS 2016 Editor SPEKTRA
Spektra: Jurnal Fisika dan Aplikasinya Vol 1 No 1 (2016): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 1 Nomor 1, Agustus 2016
Publisher : Program Studi Fisika Universitas Negeri Jakarta

STRUKTUR MIKRO DAN SIFAT MAGNETIK DARI LAPISAN TIPIS NANOKOMPOSIT Fe3O4/PVDF Ramli Ramli; Nidya Yulfriska; Yenni Darvina; Yulkifli Yulkifli; Edi Sanjaya; Ambran Hartono
Spektra: Jurnal Fisika dan Aplikasinya Vol 3 No 3 (2018): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 3 Issue 3, December 2018
Publisher : Program Studi Fisika Universitas Negeri Jakarta

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Artikel ini berhubungan dengan laporan pembuatan lapisan tipis nanokomposit Fe3O4/PVDF (Poly Vinylidine Fluoride) dengan fraksi berat nanopartikel Fe3O4 yang berbeda. Nanokomposit Fe3O4/PVDF disiapkan menggunakan metode sol-gel dan kemudian ditumbuhkan menggunakan alat spin coating di atas substrat kaca. Lapisan tipis nanokomposit Fe3O4/PVDF dikarakterisasi menggunakan XRD, FTIR, SEM, dan VSM untuk menentukan struktur mikro dan sifat magnetiknya. Fraksi berat nanopartikel Fe3O4 dalam matriks PVDF berpengaruh pada struktur mikro dan sifat magnetik nanokomposit. Hasil karakterisasi XRD dan FTIR menunjukkan bahwa nanokomposit telah terbentuk dan telah terjadi interaksi antara pengisi (Fe3O4) dengan molekul polimer PVDF. Morfologi permukaan nanokomposit memperlihatkan bentuk sperulus (spherulites) dan lamela radial. Analisis kurva histeresis dari nanokomposit Fe3O4/PVDF menunjukkan magnetisasi saturasi dari lapisan nanokomposit Fe3O4/PVDF bertambah dengan bertambahnya konsentrasi Fe3O4 dalam sampel. Pengaruh fraksi Fe3O4 dalam sampel nanokomposit Fe3O4/PVDF terhadap sifat struktur mikro dan sifat magnetik sampel dilaporkan secara rinci dalam artikel ini.

THE EFFECT OF SYNTHETIC ZEOLITES ON SENSITIVITY AND STABILITY OF URIC ACID BIOSENSOR USING CYCLE VOLTAMETRY METHOD Iza Faizah; Dwi Puryanti; Afdhal Muttaqin
Spektra: Jurnal Fisika dan Aplikasinya Vol 3 No 3 (2018): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 3 Issue 3, December 2018
Publisher : Program Studi Fisika Universitas Negeri Jakarta

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The synthesis of synthetic zeolite modified biosensor material has been carried out to detect uric acid. This study aims to look at the effect of synthetic zeolite on uric acid biosensor material on sensor stability and sensitivity. The biosensor was use to measure uric acid using uricase produced Lactobacillus plantarum. Modification of biosensor material using synthetic zeolite content of Sodalit is added in a mixture of graphite and paraffin. Carbon paste electrode (EPK) was made with graphite and paraffin comparison 70 mg : 30 mg, while zeolite modified carbon paste electrode (EPKZ) with graphite, paraffin and zeolite comparison 50 mg: 30 mg: 20 mg. In each electrode, 7.5 Î¼l of L.plantarum pellet (EPKZLP) was dropped. Electrode performance testing was carried out using Cyclic Voltammetry. Modification results affect biosensor performance such as sensitivity and stability. The highest current is produced by EPKZLP with a current range of 0.0143 - 0.0592 mA. The best sensitivity is produced in EPKZLP with a value of 0.031 mAcm-2mM-1. The best stability was found in EPKZLP with a percentage of stability on day 14 was 30.9%. The average standard deviation generated in this study is 0.0024 mA with a relative error value was 7.8%. Addition of zeolite to biosensor material produced in this study has met several criteria to be used as a sensor. Keywords: uric acid biosensor, zeolite, sodalit, sensitivity, stability.

SYNTHESIS OF SODALITE ZEOLITE FROM COAL BOTTOM ASH WITH VARIATION OF NaAlO2 CONCENTRATION USING ALKALI MELTING HYDROTHERMAL METHOD Rahmatul Hanifah; Dwi Puryanti; Afdhal Muttaqin
Spektra: Jurnal Fisika dan Aplikasinya Vol 3 No 3 (2018): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 3 Issue 3, December 2018
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (157.873 KB)

Synthesis of zeolites from bottom ash using alkali melting hydrothermal method with variation concentration of NaAlO2 solution had been done. Concentration of NaAlO2 solution was varied for 2,5 M (Z1), 2 M (Z2), 1,5 M (Z3) and 1 M (Z4). The bottom ash and NaOH are melted for 3 hours at 750C. Then, the sample is heated through a hydrothermal process with NaAlO2 crystallization medium. Then the sample is neutralized with aquades up to pH 9-10. Characterization of sample includes characterization zeolite type using of. The results of characterization using XRD show that the zeolite formed on samples Z1, Z2, and Z3 are zeolites of sodalite type and on Z4 sample of zeolite type are sodalit, nosean, and megakalsilit. The highest sodalite purity was obtained in Z3 sample, which is 73%.

IDENTIFIKASI KETEBALAN LAPISAN SEDIMEN DAN STRUKTUR BAWAH PERMUKAAN DI ZONA AMBLESAN KOTA LAMA SEMARANG BERDASARKAN DATA MIKROSEISMIK Supriyadi Supriyadi; Khumaedi Khumaedi; Sugiyanto Sugiyanto; R.H Hidayatullah
Spektra: Jurnal Fisika dan Aplikasinya Vol 3 No 3 (2018): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 3 Issue 3, December 2018
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (518.765 KB)

Sebagai kota di pesisisr panatai pulau Jawa Semarang merupakan tempat yang bersejarah dengan bangunan-bangunan kuno peninggalan Belanda yang disebut kota lama. Dalam rangka melestarikan kota lama peninggalan bersejarah tersebut perlu dilakukan kajian struktur bawah permukaan karena Semarang ini terutama daerah yang tersebar endapan alluvial sehingga memungkinkan terjadi Amblesan (subsidence). Amblesan ini dapat mengakibatkan banjir di daerah Semarang utara akibat banjir pasang (rob), serta terjadi kerusakan pada bangunan-bangunan peninggalan bersejarah tersebut. Amblesan ini disebabkan oleh beban berat di atas lapisan, deformasi lapisan tanah permukaan dan pemompaan air tanah kepermukaan. Potensi amblesan ini dapat diketahuai melalui kajian struktur bawah permukaan dengan metode mikroseismik. Mikroseismik merupakan metode geofisika yang sering digunakan untuk survey pendahuluan mendeteksi ketidakstabilan lapisan batuan dengan memanfaatkan getaran kecil dari gelombang seismic. Akuisisi data dilakukan dengan menggunakan salat Seismometer 3 komponen dan kemudian diolah dengan metode HVSR. Dari hasil pengolahan data diperoleh ketebalan lapisan sedimen pada kawasan gereja Blenduk berkisar antara 68-116 meter. Kondisi struktur bawah permukaan di kawasan Gereja Blenduk yaitu terdiri dari batuan aluvial yang terbentuk dari sedimentasi delta, top soil, lumpur, dll dengan kedalaman 30m atau lebih. Ketebalan sedimen permukannnya sangatlah tebal.

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