Fajar Arianto
Departemen Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro, Semarang

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STUDI KRITIKALITAS VHTR PRISMATIK SEBAGAI FUNGSI RADIUS BAHAN BAKAR KOMPAK DAN KERNEL Arianto, Fajar; ., Suwoto; ., Zuhair
Jurnal Iptek Nuklir Ganendra Vol 16, No 2 (2013)
Publisher : BATAN

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Radius bahan bakar kompak dan kernel selama ini dibuat tetap pada nilai baku yang diadopsi oleh proyek reaktor suhu tinggi. Radius kompak bahan bakar ditetapkan 0,6225 cm dan radius kernel bahan bakar ditentukan 0,0250 cm. Dua parameter ini diinvestigasi karena sangat mempengaruhi performa moderasi neutron dalam teras VHTR. Efek radius kernel dan bahan bakar kompak dalam bahan bakar blok VHTR sebagai representasi dari teras aktif didiskusikan dalam makalah ini. Pengkayaan 235U sebesar 12% dan fraksi packing TRISO 0,29 dikerjakan di seluruh perhitungan dengan program transport Monte Carlo MCNPX dan pustaka data nuklir energi kontinu ENDF/B-VII pada suhu 1200K. Bahan bakar blok VHTR dimodelkan secara utuh dan presisi dengan kondisi batas reflektif. Hasil perhitungan memperlihatkan ketergantungan k∞ pada radius kernel berkurang seiring dengan berkurangnya radius bahan bakar kompak. Nilai k∞ hampir tidak bergantung pada radius kernel untuk radius bahan bakar kompak 0,4000 cm. Analisis menyimpulkan bahwa, kombinasi dua parameter ini adalah cara yang tepat untuk mendapatkan nilai faktor perlipatan neutron tak hingga yang diinginkan dari teras VHTR prismatik dengan fraksi packing dan pengkayaan bahan bakar yang spesifik.
STUDY OF ELECTROOPTICS BEHAVIOUR OF NAPHTHALENE AND ANTHRACENE Firdausi, K Sofjan; Khumaeni, Ali; Richardina, Very; Arianto, Fajar; Budi, Wahyu Setia
BERKALA FISIKA 2015: Berkala Fisika Vol. 18 No. 3 Tahun 2015
Publisher : BERKALA FISIKA

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In this paper, we demonstrate electro-optics behaviour of naphthalene and anthracene using change of polarization of sample induced by external electric field. The source of light for polarization was 1 mW-he-ne Laser 633 nm. The induced external Electric field was produced by high DC voltage 0 – 7 kV. The samples were diluted in solutions-form using wash-benzene. The result shows that anthracene has higher polarizability than naphthalene, which is indicated by higher change of polarization in anthracene than naphthalene. The Assumption that potential difference is proportional to the distance between molecules is shown qualitatively by graphs of Van der Waals potential energy or force between molecules. In this case, anthracene has higher level Energy than naphthalene so that it can be used in visible excitation for environmental spectroscopy. Keywords: electro-optics, polarization, naphthalene, anthracene, Van der Waals potential energy 
PENGEMBANGAN BAHAN AJAR KEPEMIMPINAN MILITER DI SEKOLAH TINGGI TEKNOLOGI ANGKATAN LAUT SURABAYA Zumatul Atiqoh, Ayu; Arianto, Fajar
Jurnal Mahasiswa Teknologi Pendidikan Vol 10, No 1 (2016): Maret 2016
Publisher : Jurnal Mahasiswa Teknologi Pendidikan

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Abstrak Kepemimpinan Militer merupakan mata kuliah khusus dan wajib ditempuh oleh setiap mahasiswa di STTAL Surabaya. Dalam proses pembelajaran kepemimpinan militer menunjukkan bahwa mahasiswa tidak memiliki buku pegangan sendiri, sumber referensi yang dimiliki oleh mahasiswa berupa buku-buku yang direkomendasikan oleh para gadik kurang. Dosen / Tenaga Pendidik merasa kesulitan dalam mengajar karena mahasiswa belum memiliki buku pegangan sendiri, dan hanya mengandalkan kuliah tatap muka. Sedangkan di STTAL sendiri kesempatan tatap muka sangat minim. Permasalahan tersebut adalah kesenjangan yang mestinya tidak ada dan harus dapat diminimalisir dengan mengembangkan bahan ajar kepemimpinan militer untuk mahasiswa di Sekolah Tinggi Teknologi Angkatan Laut (STTAL), diperlukan uji kelayakan bahan ajar kepemimpinan militer yang telah dikembangkan, dan diperlukan uji efektifitas bahan ajar kepemimpinan militer yang telah dikembangkan dengan tujuan dihasilkan bahan ajar Kepemimpinan Militer untuk mahasiswa di Sekolah Tinggi Teknologi Angkatan Laut (STTAL) Surabaya dalam memfasilitasi belajar. Bahan ajar yang akan digunakan adalah berbentuk cetak dengan jenis bahan ajar yaitu buku ajar. Buku ajar kepemimpinan militer ini dikembangkan dengan model pengembangan Reseacrh and Development (R&D) dari Borg and Gall yang diadaptasi dari Dick, W, Carey, L.,& Carey. J.O. Bahan ajar tersebut kemudian di ujicobakan kepada subjek penelitian yaitu 2 ahli media, 2 ahli materi, dan 2 ahli evaluasi butir soal, serta kepada 26 mahasiswa STTAL. Jenis data yang digunakan dalam pengembangan bahan ajar ini yaitu data kualitatif dan kuantitatif, data kuantitatif didapat berdasarkan hasil angket terbuka kepada ahli materi, ahli media, dan angket yang diberikan untuk uji coba perorangan, kelompok kecil, dan kelompok besar. Data kualitatif didapat berdasarkan hasil deskriptif dari evauasi butir soal. Teknik analisis data yang digunakan adalah teknik persentase untuk angket, serta teknik uji-t untuk tes. Hasil uji kelayakan bahan ajar berdasarkan hasil angket dengan menggunakan rumus presentase dihasilkan ahli materi 96,67% (sangat baik), ahli media 93,33% (sangat baik) serta hasil angket uji coba perorangan 100% (sangat baik), uji coba kelompok kecil 97,5% (sangat baik), dan uji coba kelompok besar 96% (sangat baik). Sehingga dapat disimpulkan bahwa bahan ajar kepemimpinan militer ini layak digunakan dalam kegiatan pembelajaran di STTAL Surabaya. Selanjutnya untuk keefektifan bahan ajar diperoleh perhitungan dengan rumus t-test, dihasilkan d.b = N-1 = 26-1 = 25 (dikonsultasikan dengan table nilai t) dengan nilai t0,05 harga tabel = 2,06 maka dapat diketahui bahwa thitung lebih besar dari pada ttabel dengan perbandingan angka thitung = 11,10 > ttabel = 2,06. Sehingga dapat disimpulkan bahwa penggunaan bahan ajar efektif digunakan dalam pembelajaran. Kata Kunci: Pengembangan, Bahan Ajar, Kepemimpinan Militer Abstract Military leadership is a subject that must be taken by every student in STTAL Surabaya. Military Leadership in the learning process indicates that a student does not have its own handbook, reference sources owned by the students in the form of books recommended by lecturers lacking. Lecturer find it difficult to teach because the student has not had its own handbook, and only rely on face to face lectures. That problem is the gap that should not exist and should be minimized by developing teaching materials military leadership to students at the College of Technology Navy (STTAL), required due diligence teaching materials military leadership that has been developed, and the necessary test the effectiveness of teaching materials military leadership has been developed with the aim of military leadership produced teaching materials for students in the College of Naval Technology (STTAL) Surabaya in facilitating learning. Teaching materials to be used is print the form with the kind of teaching materials namely textbooks. Textbook was developed with the military leadership development model Reseacrh and Development (R & D) from Borg and Gall adapted from Dick, W, Carey, L., & Carey. J.O. The teaching materials later in ujicobakan to the subject of research that two media experts, two subject matter experts, and two expert evaluation items, as well as to 26 students STTAL. The data used in the development of these materials, namely quantitative and qualitative data, quantitative data obtained based on the results of the open questionnaire to the subject matter experts, media experts, and questionnaires given to individual testing, small group, and large groups. The qualitative data obtained based on the descriptive results of evaluation items. Data analysis technique used is the percentage of the questionnaire, as well as t-test technique to the test. The results of the feasibility test of teaching materials based on the results of questionnaires using a percentage formula produced material experts 96.67% (excellent), media experts 93.33% (excellent) and the results of the questionnaire individual testing of 100% (excellent), group trial small 97.5% (very good), and a large group trial 96% (excellent). It can be concluded that the military leadership teaching material is fit for use in learning activities in STTAL Surabaya. Furthermore, to the effectiveness of teaching materials obtained by the calculation formula t-test, resulting db = N-1 = 26-1 = 25 (consulted with the table value of t) with values ​​t0,05 price table = 2.06, it can be seen that the larger thitung of the ttabel with comparative figures t = 11.10> table = 2.06. It can be concluded that the use of effective instructional materials used in learning. Keywords: Development, Instructional Materials, Military Leadership
Pengaruh Ozon yang Dibangkitkan Melalui Reaktor Plasma Berpenghalang Dielektrik Elektroda Silinder Spiral Terhadap Pengawetan Cabai Saraslifah, Saraslifah; Nur, Muhammad; Arianto, Fajar
YOUNGSTER PHYSICS JOURNAL Vol 5, No 4 (2016): Youngster Physics Journal Oktober 2016
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Research on the effects of ozone generated by the plasma reactor cylindrical spiral electrode to the shelf life of chili has been done in Plasma Physics Laboratory, Diponegoro University. This study aims to obtain optimal voltage values to produce maximum ozone. And obtaining effect of ozonation time and storage for chili quality. Ozon which used is produced by dielectric barrier discharge plasma reactor with spiral cylinder configuration. This ozon , which produced by the reactor dissolved in water for washed the chili. Chili using ozone washing is done with a variety of washing time 0,5,10,15,20,25 and 30 minutes. The chili then stored in a refrigerator at a temperature of 17 ℃ for 25 days. Characterization of the reactor showed that the greater value of the applied voltage, increased current and concentration of ozone produced. Voltage used for ozonantion is 2400 V with a concentration of ozone generated at 23.75 ppm. Ozone dissolved in water to wash the chili with dissolved ozone concentration is 1.66 ppm or 7%. From the analysis of the level of damage chili, ozonation results with lowest damage rate is at the time of treatment 15 minutes with a percentage of 8% damage to the shelf life of 25 days. From the test results of proximate preservation chili using ozone is not particularly affect the content in chili peppers that is safe to use. The longer the treatment time, reduce the amount of bacteria on pepper growing. At thetime of treatment 15 minutes colonies of fungi reduced til 50,8 % and bacteria were reduced 51.7%. It seen from the results of TPC (Total Plate Count).
KARAKTERISASI REAKTOR PLASMA BERARUS NEGATIF DENGAN KONFIGURASI ELEKTRODA TITIK-BIDANG DAN PENERAPANNYA PADA KAIN POLYESTER RAJUT GREY Hasan, Siti Nurjannah; Muhlisin, Zaenul; Triadyaksa, Pandji; Arianto, Fajar
BERKALA FISIKA Vol 22, No 1 (2019): Berkala Fisika Vol. 22 No. 1 Tahun 2019
Publisher : BERKALA FISIKA

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Research on characterisations of plasma reactor with negative current of square-point electrode configuration and its application on grey polyester knit fabric has been carried out. The objectives of this reseach were obtaining characterisation of negative plasma reactor, either with or without sample of the polyester knit fabric, getting ion mobility value, gaining the characterisation of irradiated polyester knit fabric of grey, and obtaining SEM results indicating the morphological changes of the fabric. A Plasma-Electrode Point Plasma reactor which is connected to a high-voltage DC power plant was used in this study. The size of pointfield electrodes was 15 x 15 cm2 with a 1.6 cm needle. The size of the grey knit polyester fabric used was 10 x 10 cm2. Variations in distance between electrodes were 1.5 cm, 1.8 cm, 2.1 cm 2.4 cm, 2.7 cm, 3.0 cm, and 3.3 cm. The results have shown that if the voltage increases, then the current value increses. The voltage which is needed to produce a lower current values is that the presence of a polyester knit fabric of grey. The highest voltage and current values witout sample can be found at a distance of 3.3 cm with a current value of 2.5 mA at a voltage of 3.027 kV, compared with presence of a sample, a current value of 1.6 mA at a voltage of 3.445 kV. The greater distance of the electrode, the smaller ion of the mobility is achieved. Based on the results of the water drop test showed that the longer the irradiation of the cloth, the faster duration of absorption. This is indicated by a distance of 2.4 cm in the duration of 5 minutes obtained the absorption time of 2.15 seconds while in the duration of 35 minutes obtained 1.47 seconds. In the SEM test, it is used 2 cloths where the first cloth used as a control or not subjected to plasma that has little damage where as the second fabric is subjected to plasma treatment with the time of irradiation is about 20 minutes that have damage or peeling on the surface of polyester knit fabrics grey.Keywords: Plasma corona, multi-point field, ion mobility, polyester fabric, textile treatment, the meeting properties of fabric.