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All Journal International Journal of Power Electronics and Drive Systems (IJPEDS) International Journal of Renewable Energy Development POSITRON Jurnal Sains dan Pendidikan Fisika Jurnal Ilmu Ternak Veteriner WARTAZOA Indonesian Bulletin of Animal and Veterinary Sciences PROFIT : Jurnal Administrasi Bisnis Jurnal Fisika Unand JFA (Jurnal Fisika dan Aplikasinya) PROSIDING SEMINAR KIMIA Jurnal Fisika FLUX JURNAL BIOLOGI INDONESIA International Research Journal of Business Studies (E-Journal) Jurnal Penelitian dan Pengkajian Ilmu Pendidikan: e-Saintika Indonesian Journal of Electrical Engineering and Computer Science Edunesia : jurnal Ilmiah Pendidikan Computational and Experimental Research in Materials and Renewable Energy (CERiMRE) Makara Journal of Science Sewagati Jurnal Akuntansi Manado (JAIM) International Research Journal of Business Studies Journal of Engineering and Technological Sciences
Darminto .
Dept. Of Physics, Fac. Of Math. And Natural Sciences-Sepuluh November Institute Of Tech. Surabaya Kampus ITS Sukolilo, Surabaya 60111, Indonesia
Aerospace Engineering Arts Humanities Automotive Engineering Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Languange, Linguistic, Communication & Media Materials Science & Nanotechnology Mathematics Physics Public Health Social Sciences Veterinary Other

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Penerapan Model Vorteks Gelas Termodifikasi pada Kristal Tunggal Superkonduktor Bi2Sr2CaCu2O8+ Cahyoingrat, Suryo E.; Darminto, Darminto
Jurnal Fisika dan Aplikasinya Vol 2, No 2 (2006)
Publisher : Lembaga Penelitian dan Pengabdian Kepada Masyarakat, LPPM-ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (281.636 KB) | DOI: 10.12962/j24604682.v2i2.990

Abstract

Analisis sistematis telah dilakukan pada data resisitivitas dari dua sampel kristal tunggal Bi2Sr2CaCu2O8+ (Bi-2212) dengan kandungan oksigen berbeda yang mempunyai Tc = 93 K dan 70 K dalam pengaruh medan magnetik antara 0 H 40 kOe yang berarah sejajar sumbu-c kristal. Model dengan rumusan panjang koherensitermodifikasi yang diperkenalkan oleh Rydh, dkk. telah memberikan penjelasan yang konsisten perilaku vorteks gelas dengan memberikan nilai eksponen kritis (s) yakni 4,7 dan 2,0 berturut-turut untuk sampel yang bersesuaian. Selain itu penskalaan kurva pada model ini memberikan nilai parameter pining () berturut-turut 0,45 dan 0,54 untuk kedua kristal.
Pengujian Teori Trade-Of Dan Pecking Order Dengan Satu Model Dinamis Pada Perusahaan Publik Di Indonesia Darminto, Darminto; Haymans Manurung, Adler
INTERNATIONAL RESEARCH JOURNAL OF BUSINESS STUDIES Vol 1, No 1 (2008): May 2008
Publisher : Universitas Prasetiya Mulya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21632/irjbs.1.1.24

Abstract

This article explores determinant of capital structure in Indonesia.Empirical study using Regression in model is done by includingvariable suggested by Trade of Theory, Pecking Order Theory, andcombination of those theories. The result shows that determinantfactors in the Trade of Theory have more ability to explain the capitalstructure than deficit cash flow factor in pecking order theory. Othervariables that are also significant are firm size and collateral capacity.Its is possible that rejection of Pecking Order Theory is due to markettiming argument in long term financing.Keywords: leverage, pecking order theory, trade-off theory, capital structure, size and tangible fxed asset.
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.
PENGARUH PELAPISAN PERMUKAAN PARTIKEL SiC DENGAN OKSIDA METAL TERHADAP MODULUS ELASTISITAS KOMPOSIT Al/SiC Zainuri, M; Siradj, Eddy S; Priadi, Dedi; Zulfia, Anne; Darminto, Darminto
Makara Journal of Science Vol. 12, No. 2
Publisher : UI Scholars Hub

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Abstract

The Influence of Coating Oxide Metal on Surface of SiC Particles to Elastic Modulus of Al/SiC Composites. The isotropic composites of Al/SiC is made by powder metallurgy method, the quality of mechanical materials depend on interfacial bonding between matrix (Al) and reinforcement (SiC). The quality of interfacial bonding can influence to elastic modulus of composites which is made by solid process. SiC particles were coated by metal oxide aim to enhance quality interfacial bonding between matrix and reinforcement. These research using three kinds of coating materials, which are Mg oxide, Cu oxide and Al oxide, and these materials were deposited on surface of SiC particles. From three kinds of materials coating Al2O3 is the best to enhance quality interfacial bonding between matrix and reinforce than the others as CuO or MgO. There is Intermetalic phase formatted on CuO coating, and MgO coating have many porous where they can make decrease quality of Al-SiC composites. All of volume fraction of SiC on the Al/SiC composites, which oxide aluminum coating on SiC surface have highest value of elastic modulus than the others metal oxides.
PENGARUH PELAPISAN PERMUKAAN PARTIKEL SiC DENGAN OKSIDA METAL TERHADAP MODULUS ELASTISITAS KOMPOSIT Al/SiC Zainuri, M; Siradj, Eddy S; Priadi, Dedi; Zulfia, Anne; Darminto, Darminto
Makara Journal of Science Vol. 11, No. 2
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The Influence of Coating Oxide Metal on Surface of SiC Particles to Elastic Modulus of Al/SiC Composites. The isotropic composites of Al/SiC is made by powder metallurgy method, the quality of mechanical materials depend on interfacial bonding between matrix (Al) and reinforcement (SiC). The quality of interfacial bonding can influence to elastic modulus of composites which is made by solid process. SiC particles were coated by metal oxide aim to enhance quality interfacial bonding between matrix and reinforcement. These research using three kinds of coating materials, which are Mg oxide, Cu oxide and Al oxide, and these materials were deposited on surface of SiC particles. From three kinds of materials coating Al2O3 is the best to enhance quality interfacial bonding between matrix and reinforce than the others as CuO or MgO. There is Intermetalic phase formatted on CuO coating, and MgO coating have many porous where they can make decrease quality of Al-SiC composites. All of volume fraction of SiC on the Al/SiC composites, which oxide aluminum coating on SiC surface have highest value of elastic modulus than the others metal oxides.
PENGARUH PELAPISAN PERMUKAAN PARTIKEL SiC DENGAN OKSIDA METAL TERHADAP MODULUS ELASTISITAS KOMPOSIT Al/SiC Zainuri, M; Siradj, Eddy S; Priadi, Dedi; Zulfia, Anne; Darminto, Darminto
Makara Journal of Science Vol. 12, No. 2
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The Influence of Coating Oxide Metal on Surface of SiC Particles to Elastic Modulus of Al/SiC Composites. The isotropic composites of Al/SiC is made by powder metallurgy method, the quality of mechanical materials depend on interfacial bonding between matrix (Al) and reinforcement (SiC). The quality of interfacial bonding can influence to elastic modulus of composites which is made by solid process. SiC particles were coated by metal oxide aim to enhance quality interfacial bonding between matrix and reinforcement. These research using three kinds of coating materials, which are Mg oxide, Cu oxide and Al oxide, and these materials were deposited on surface of SiC particles. From three kinds of materials coating Al2O3 is the best to enhance quality interfacial bonding between matrix and reinforce than the others as CuO or MgO. There is Intermetalic phase formatted on CuO coating, and MgO coating have many porous where they can make decrease quality of Al-SiC composites. All of volume fraction of SiC on the Al/SiC composites, which oxide aluminum coating on SiC surface have highest value of elastic modulus than the others metal oxides.
Synthesis and Characterization of ZnO Thin Layers using Sol-Gel Spin Coating Method Ahzan, Sukainil; Darminto, Darminto; Nugroho, Ferry Anggoro Ardy; Prayogi, Saiful
Jurnal Penelitian dan Pengkajian Ilmu Pendidikan: e-Saintika Vol. 5 No. 2: July 2021
Publisher : Lembaga Penelitian dan Pemberdayaan Masyarakat (LITPAM)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36312/esaintika.v5i2.506

Abstract

The potential of thin layer in many applications has led to research on the development of many new materials and their fabrication methods. This study aimed to synthesize a thin layer of ZnO using the facile and low-cost sol-gel spin coating method. The ZnO thin layer is deposited on a glass substrate and analyzed to observe the influence of the deposition variables such as heating and rotation speed, and its aging. The characterization methods include the identification of the formed phase using X-Ray Diffractometer (XRD), and the microstructure and elemental composition using Scanning Electron Microscopy (SEM) coupled with EDS (Energy Dispersive Spectrometer). The study shows that a thin layer of ZnO is successfully deposited on a glass substrate by heat treatment at temperatures of 300 oC and 500 oC. Furthermore, XRD reveals that higher heating temperatures result in higher diffraction peak intensity. At a heating temperature of 300 °C crystals are formed but are not yet perfectly oriented, while they are at 500 °C. On the other hand, higher spin coating rotation speed gives rise to lower intensity of diffraction peak. The ZnO crystallization is easier to form in the coating process with a lower rotation (1500 rpm). Interestingly, the thin layer is stable over time where there is no significant change in each sample, both in terms of intensity and width of the ZnO crystal peak. The results indicate that gel precursor aged less than two days can form ZnO crystals. Finally, SEM results show that the surface morphology of the ZnO layer heated at 500 oC has an average grain size of 300 nm. Based on the cross-sectional results of SEM shows that the higher the coating rotation speed has resulted the thinner of the ZnO layer, where the thickness of the resulting layer is on order >5 mm.
The Optical Energy Gap of the Semiconducting Intrinsic Layer for Organic Solar Cell Applications Firdaus, Aulia Anisa; Purwandari, Endhah; Asih, Retno; Sholih, Ahmad; Darminto, Darminto
Computational And Experimental Research In Materials And Renewable Energy Vol 6 No 1 (2023): May
Publisher : Physics Department, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/cerimre.v6i1.39254

Abstract

The optical energy gap of the semiconducting intrinsic layer plays a crucial role in determining the increase in efficiency. The carbon-based biomass can be a choice for the silicon used as solar cell material. Here, we proposed the best biomass that can be used as a semiconductor component in solar cell applications. Coconut shells as bio-waste and palmyra sap, which are available in most areas of Indonesia, can be the best candidates to be considered. The XRD measurement showed both organic materials have an amorphous phase. The coconut shells sample has two peaks that are identical to graphene peaks, therefore this material is called graphenic-like carbon (GC). Furthermore, from the UV-visible spectroscopy, it was shown that both materials have a high transmittance of more than 95%, which indicates that they have transparent properties. Also, the Tauc plot method gives information about the optical energy gap of coconut shell charcoal (GC) and palmyra sap (a:C) which are 2.67 and 1.83 eV, respectively. From this result, palmyra sap becomes promising material to be applied as an intrinsic layer for semiconducting components in solar cell applications.Keywords: Amorphous phase, Coconut shells charcoal, Optical energy gap, Palmyra sugar.
Analisis Keputusan Pendanaan Investasi: Studi Kasus di Perusahaan Penggemukan Sapi Indonesia Nurshabrina, Atiqa Taqiyya; Darminto, Darminto
Jurnal Akuntansi Manado (JAIM) Volume 5. Nomor 1. April 2024
Publisher : Fakultas Ekonomi Universitas Negeri Manado

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.53682/jaim.vi.8235

Abstract

Penelitian ini bertujuan untuk memberikan rekomendasi keputusan pendanaan terkait investasi PT PSI berupa penambahan feedlot di Bogor karena perusahaan belum memiliki modal yang cukup sehingga berakibat pembangunan feedlot terhambat. Untuk mencapai tujuan, penelitian dilakukan dengan menggunakan strategi studi kasus dengan data diperoleh dari dokumentasi dan wawancara serta diolah menggunakan descriptive qualitative analysis. Berdasarkan simulasi dan asumsi yang digunakan dalam penelitian ini, disimpulkan bahwa struktur modal PT PSI saat ini dengan 72% pendanaan utang belum optimal karena struktur modal yang optimal adalah 25%-35% pendanaan utang. Rekomendasi tindakan yang dapat dilakukan PT PSI adalah menyesuaikan struktur modal agar optimal dengan meningkatkan modal pemegang saham minimal 61 kali dari saldo saat ini. Penelitian ini mengisi celah dari penelitian terdahulu, yaitu penelitian ini menggunakan pendekatan untuk perusahaan tertutup, di mana  berbeda dengan penelitian terdahulu yang didominasi oleh lingkup perusahaan publik, dan mempertimbangkan faktor yang belum dipertimbangkan pada penelitian terdahulu, seperti biaya kebangkrutan dan makroekonomi.
Synthesis of CdS Nanoparticles Using The Brimstone Suryajaya, Suryajaya; Safitri, Ayu; Suarso, Eka; Haryanti, Ninis Hadi; Manik, Tetti Novalina; Darminto, Darminto
POSITRON Vol 14, No 2 (2024): Vol. 14 No. 2 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v14i2.77273

Abstract

This paper explains and demonstrates how to synthesize Cadmium Sulphide (CdS) nanoparticles (NPs) using brimstone. The brimstone is obtained from Ijen volcanic crater in East Java Indonesia and used as the source of sulfur gas (S2) instead of Na2S. The brimstone was crushed and dissolved in potassium hydroxide (KOH) solution while heated. Acetic acid (CH3COOH) was added, to release the S2 gas. The liquid-gas method was used to prepare the CdS colloid solution. In this study, the effect of variations in the concentration and volume of CH3COOH, temperature variation, and exposure time on the synthesis of colloidal solutions of CdS NPs will be investigated. The absorption edge of the CdS colloidal solution compared to the bulk material experienced a blue shift. This is the evidence of the formation of NPs in solution. It is confirmed by FTIR which shows a CdS absorption peak at 467 cm-1. The radius of CdS NPs was calculated using the Efros equation to obtain a result of approximately 2 nm. Particle size analyzer (PSA) provides a much larger particle size of 20.8 nm. It is assumed that the NPs were agglomerated. Several treatments given, such as varying the volume of CH3COOH, varying temperature, stirring, and varying synthesis time, did not affect the size of the NPs.  The cadmium sulfide produced would be used as photocatalist in water treatment application.
Co-Authors A Ratnawati A Wiyono abdurrouf Abdurrouf Adler Haymans Manurung Agung Suwandaru Agus Wiyono Ahzan, Sukainil Alimuddin Ali Anne Zulfia Arifin, Rizal Bambang Subali Budhi Priyanto Budi Priyanto Cahyoingrat, Suryo E. Cahyono, Yoyok D.A Hewajuli Dadan Hamdani, Dadan Daniels, Peter Daniels, Peter Dedi Supriadi Dharmayanti, N.L P.I. Dharmayanti, N.L P.I. Dharmayanti, NLP Dharmayanti, NLP Eddy S Siradj Eko Handoyo Endang Siti Astuti Endhah Purwandari Fahmi Astuti, Fahmi Fatimah Karunia Sultera Field, Hume Field, Hume Firdaus, Aulia Anisa Gatut Yudoyono H Hamid Haniffudin Nurdiansah Hartawan, R. Hartawan, R. Helmy Hamid Hesti Irnanta Hewajuli, D.A. Hewajuli, D.A. I Wayan T. Wibawan Ida Ayu Putu Sri Widnyani Ida Widaningrum, Ida Indrawati Sendow Intifadhah, Sahara Hamas Iwan Dini Iwan Yahya Jagoda Ignjatovic Johari, Norhasnidawani Joni Dwi Pribadi Kholis Nurhanafi Kolif Yulianto L Parede Lee, Vannajan Sanghiran Lintang Edityastono Malik Anjelh Baqiya Manik, Tetti Novalina Martin Malole Mashuri Mashuri Mochammad Zainuri Morrissy, Chris Morrissy, Chris Muhammad Taqiyuddin Muhammad Zainuri Muharam Saepulloh Munir, Rahmawati Muzakki, Fikrun Najib N. Suryana N.L.P Indi Dharmayanti N.L.P.I Dhamaryanti N.L.P.I Dharmayanti N.L.P.I. Dharmayanti Ninis Hadi Haryanti, Ninis Hadi NLP Indi Dharmayanti Nugroho, Ferry Anggoro Ardy Nuni Widiarti Nurma Sari, Nurma Nurshabrina, Atiqa Taqiyya P Ronohardjo Prayogi, Saiful Prayogi, Soni Puspita, Niniek Fajar R Damayanti R Indriani R M A Adjid R. Indriani R.M Abdul Adjid R.M. Abdul Adjid R.M.A. Adjid Ratnawati, A. Ratnawati, A. Retno Asih, Retno RISA INDRIANI Risa Indryani Risdiana, Risdiana Rizoputra, Ivan Rizqy Wahyu Septiono S Hardjoutomo Saleh, Muh Santoso, Tanto Budi Shaliha, Shaliha Shinta Maharani Trivena Sholih, Ahmad Simon Sadok Siregar, Simon Sadok Simson Tarigan Siti Ragil Handayani Sitorus, Mido Ester Sjamsul Bahri SRI WARDANI Suarso, Eka Suhadak Suhadak Suminar Pratapa Suryajaya Suryajaya, Suryajaya Susan M Noor Susi Soviana T Sjafriati T Syafriati Taher Al habsji Tatty Syafriati Totok Wianto Upik Kesumawati Hadi W. Asmara W. T. Artama, W. T. Wahyudi, Sriati Winardi, Yoyok Zainul Arifin Zainuri, M Zulkarnain, Zulkarnain