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All Journal BERKALA FISIKA POSITRON Jurnal Teknologi INDONESIAN JOURNAL OF APPLIED PHYSICS
Iwan Yahya
Universitas Sebelas Maret (UNS)
Astronomy Computer Science & IT Electrical & Electronics Engineering Energy Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering Physics

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 1 
DETEKSI ARITMIA BLOKADE CABANG BERKAS KIRI PADA ELEKTROKARDIOGRAM DENGAN JARINGAN SYARAF TIRUAN BERDASARKAN FITUR INTERVAL QR DAN RS Primadyanie, Nistya Rischa; Nuryani, Nuryani; Purwanto, Hery; Yahya, Iwan; Lestari, Anik
BERKALA FISIKA 2014: Berkala Fisika Vol. 17 No. 3 Tahun 2014
Publisher : BERKALA FISIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (164.717 KB)

Abstract

Left branch bundle block (LBBB) detection system have been done and tested. The system created by using Artificial Neural Network (ANN). Some ANN methods have been investigated.  Electrocardiogram features that represent the characteristic of LBBB which were QR interval and RS interval used as input. Output of the system was electrocardiogram status to detect LBBB and normal beat. LBBB detection has been done with various input with QR interval, RS interval, QR and RS interval. Detection system have been tested using chlinical data and shown that MLP method gave the best performance. Its performance shown by sensitivity, specificity, and accuracy up to 99,92%, 100%, and 99,94% . Keywords: LBBB, artificial neural network, QR interval, RS interval
CHARACTERIZATION OF PERFORMANCE ACOUSTIC SANDWICH COMPOSITE WITH A CORE OF POLYURETHANE FOAM-AGAVE SISALANA FIBER REINFORCED POLYESTER FOR NOISE ABSORPTION Yudhanto, Ferriawan; Wisnujati, Andika; Yahya, Iwan
Jurnal Teknologi Vol 8 No 2 (2015): Jurnal Teknologi
Publisher : Jurnal Teknologi, Fakultas Teknologi Industri, Institut Sains & Teknologi AKPRIND Yogyakarta

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Abstract

Bahan penyerap memiliki karakteristik akustik yang memantulkan dan menyerap gelombang bunyi. Penyerapan oleh bahan berpori sangat berguna untuk mengurangi tingkat kekuatan bunyi yang terjadi sehingga dapat mengurangi kebisingan di dalam ruangan. Koefisien Penyerapan Bunyi (NAC) dari Acoustic Sandwich Composite (ASC) diuji dengan menggunakan tabung Kundts Tube impedansi dua mikrofon sesuai dengan standar ASTM 1050-98. Dimensi ASC terdiri dari 1 inti dan 2 kulit dengan diameter 100 mm. Kulit di sisi bagian depan didisain memiliki 5 lubang (d = 10 mm) dengan variasi 4 ketebalan yang berbeda dari busa poliuretan (busa-PU) yaitu 10, 20, 30 dan 40 mm yang digunakan sebagai inti dari ASC. Kulit atau skin di kedua sisi komposit sandwich terbuat dari poliester yang diperkuat bahan serat alam agave sisalana acak dan panjang dengan tebal 5 mm. Nilai Koefisien Penyerapan Bunyi (NAC) diberikan nilai 0-1, yang berarti penyerapan bunyi tidak ada akan bernilai 0, dan penyerapan bunyi mencapai maksimum apabila bernilai 1 pada rentang frekuensi 0 Hz -1,6 kHz. Pada penelitian ini terlihat sifat busa polyurethane dengan ketebalan 30 mm baik pada rentang frekuensi rendah dengan nilai NAC tertinggi adalah 0,46. ASC dengan ketebalan busa PU 30 mm memiliki kenaikan harga NAC di frekuensi rendah (400 Hz-1000 Hz), nilai tertinggi 0,80 di frekuensi 800 Hz. ASC dengan ketebalan busa PU 10 mm baik untuk frekuensi menengah (1000 Hz-1600), nilai tertinggi 0,89 pada frekuensi 1200 Hz.
Perluasan Kinerja Akustik Limbah Kayu Batang Kelapa Sawit Termodifikasi Bahan Formaldehida Manik, Tetti Novalina; Shaliha, Shaliha; Siregar, Simon Sadok; Santoso, Tanto Budi; Yahya, Iwan; Mashuri, Mashuri; Zainuri, Muhammad; Darminto, Darminto
POSITRON Vol 12, No 2 (2022): Vol. 12 No. 2 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (442.893 KB) | DOI: 10.26418/positron.v12i2.55963

Abstract

Chemical modifications for waste oil palm trunks had carried out as acoustic material. This modification was conducted in two stages. Firstly, formalization with formaldehyde solution and secondly is impregnation with melamine-formaldehyde resin. Formalization was conducted in alkaline condition (pH 10) for 3 days and 5 days. Impregnation was carried out under pressure 3 bar and 5 bar and held for an hour. For completed these modification, the samples was cured at 120oC for 10 minutes and then dried at (103±2)oC to reached moisture content of less than 6%. This modification has changed the chemical structure and the morphology of wood, as shown by the FTIR and SEM results. The samples became denser, stronger and more rigid. Furthermore, the mechanical and physical properties of modified wood are also increasing. The absorption coefficient decreases with increasing formalization time and impregnation pressure. Based on trend of absorption coefficient, BKS wood can be applicated as resonant absorber with work class from A to class B and D.
Influence of Sugar Palm Ash Fraction and Resonator Configuration on Acoustic Absorption Performance of Expose Brick R, Zulfa Kamila; Yahya, Iwan; U, Utari
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 4, No 01 (2014): April
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v4i01.1160

Abstract

Sound absorption performance optimization of expose brick has been conducted in associated with the fraction of sugar palm ash in its raw material and configuration of Helmholtz resonators inside the brick structure. The testing was conducted experimentally refer to ASTM E-1050-98 standard procedure. In this case there are three variations sugar palm ash fractions of 0%, 5%, and 10%, as well as two array resonator configurations. The results showed that the brick with fraction of 10% sugar palm ash has the best sound absorption performance. As for the configuration of array identical Helmholtz resonator giving better performance improvement at low frequency span than complex resonator structure with coupled cavity where the best performance occur on(376-488) Hz frequency range with the absorption coefficient α of 0.54.
Modifikasi Permukaan Elemen Peredam Bising dengan Profil Berbentuk Prisma Kusuma, Julius Indra; Harjana, H; Yahya, Iwan
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 6, No 01 (2016): April
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v6i01.1794

Abstract

The influence of surface modification by using prism shaped profile on the sound absorption of absorber element was investigated experimentally. A prime number based configuration of the two types opened and closed type rism shaped profile inclusion was tested by using impedance tube according ASTM E1050 standard. The result shows that sound absorption at low frequency band below 200 Hz increased with the increasing of closed prism number. It is related to the coupling effect between the cavities of the absorber element and the prisms that changes reactance of the coupled structure. In the other side, a half wave resonance like effect occur on the use of opened prisms inclusion, which is increase the sound absorption performance at mid to high frequency range between 800 Hz to 1.25 kHz.
Co-Authors Anik Lestari Budi Legowo Darminto . Darsono Darsono Ferriawan Yudhanto, Ferriawan Harjana Harjana Harjana, H Holyness Nurdin Singadimedja Koesuma, Sorja Kusuma, Julius Indra Manik, Tetti Novalina Mashuri Mashuri Muhammad Zainuri Nistya Rischa Primadyanie, Nistya Rischa Nuryani Nuryani R, Zulfa Kamila Salsabila, Unik Hanifah Santoso, Tanto Budi Shaliha, Shaliha Simon Sadok Siregar, Simon Sadok U, Utari