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All Journal Jurnal Penelitian Pendidikan IPA (JPPIPA) Indonesian Journal of Chemistry Jurnal Ilmu Fisika Molekul: Jurnal Ilmiah Kimia Jurnal Fisika Indonesia
Sholihun, Sholihun
Computational Physics Research Group, Department Of Physics, Faculty Of Mathematics And Natural Sciences, Universitas Gadjah Mada, Sekip Utara BLS 21, Yogyakarta 55281, Indonesia
Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Earth & Planetary Sciences Education Energy Materials Science & Nanotechnology Physics

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Statistical Comparison of IMERG Precipitation Products with Optical Rain Gauge Observations over Kototabang, Indonesia Helmi Yusnaini; Ravidho Ramadhan; Marzuki Marzuki; Ayu Putri Ningsih; Hiroyuki Hashiguchi; Toyoshi Shimomai; Mutya Vonnisa; Harmadi Harmadi; Wiwit Suryanto; Sholihun Sholihun
Jurnal Ilmu Fisika (JIF) Vol 14 No 1 (2022): March 2022
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jif.14.1.10-20.2022

Abstract

Satellite-based precipitation estimates play a crucial role in many hydrological and numerical weather models, especially to overcome the scarcity of rain gauge data. Globally gridded rainfall product from Integrated Multi-Satellite Retrievals for Global Precipitation Measurement (GPM) (IMERG) has been used in a wide range of hydrological applications. However, the IMERG is inherently prone to errors and biases. This study evaluated the performance of the IMERG-Final run (IMERG-F) product to estimate rainfall in a mountainous area of Sumatra. Validation was carried out using optical rain gauge (ORG) data for 15 years (2002-2016), at Kototabang, West Sumatra, Indonesia. In general, IMERG-F overestimated rainfall in all time scales. The longer the time scale was, the better the performance of IMERG-F we obtained. This feature was indicated by all quantities of continuous and categorical statistical matrices used. The performance of IMERG-F was lower than in other areas of the Maritime Continent, except for the probability of detection (POD) value. IMERG-F could detect rain very well, including for daily and hourly data, but the false alarm rate (FAR) was also relatively high. Such high FAR value may indicate a significant small-scale spatial rainfall variability in mountainous area of Sumatra.
The Interaction of Air Pollutant Molecules with Germanene and Silicene: a Density Functional Theory Study Muhammad Rifqi Al Fauzan; Wijayanti Dwi Astuti; Ghorby Al Fauzan; Sholihun Sholihun
Molekul Vol 13, No 1 (2018)
Publisher : Universitas Jenderal Soedirman

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (470.763 KB) | DOI: 10.20884/1.jm.2018.13.1.419

Abstract

We investigate the adsorption of atmospheric pollutants on germanene and silicene using density functional theory (DFT) calculations. In this study, we use carbon monoxide (CO) and nitric oxide (NO) as the pollutant molecules. Electronic properties of germanene and silicene are explored to obtain a good understanding in the adsorption process. Our calculation results show both germanene and silicene provide an identical mechanism of adsorption. Germanene and silicene adsorb CO and NO spontaneously with physisorption and chemisorption types for CO and NO molecules, respectively. We also conduct the Mulliken charges calculations to evaluate the transformation of atomic charges due to the adsorption process. From Mulliken charge calculation results we can confirm the existence of charge transfer between the adsorbent materials and the pollutant molecules. This phenomenon lies behind the occurrence of the adsorption process.
Ground Validation of GPM IMERG-F Precipitation Products with the Point Rain Gauge Records on the Extreme Rainfall Over a Mountainous Area of Sumatra Island Ravidho Ramadhan; Marzuki Marzuki; Helmi Yusnaini; Ayu Putri Ningsih; Hiroyuki Hashiguchi; Toyoshi Shimomai; Mutya Vonnisa; Syarifatul Ulfah; Wiwit Suryanto; Sholihun Sholihun
Jurnal Penelitian Pendidikan IPA Vol. 8 No. 1 (2022): January
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v8i1.1155

Abstract

Accurate satellite precipitation estimates over areas of complex topography are still challenging, while such accuracy is of importance to the adoption of satellite data for hydrological applications. This study evaluated the ability of Integrated Multi-satellitE Retrievals for GPM -Final (IMERG) V06 product to observe the extreme rainfall over a mountainous area of Sumatra Island. Fifteen years of optical rain gauge (ORG) observation at Kototabang, West Sumatra, Indonesia (100.32°E, 0.20°S, 865 m above sea level), were used as reference surface measurement. The performance of IMERG-F was evaluated using 13 extreme rain indexes formulated by the Expert Team on Climate Change Detection and Indices (ETCCDI). The IMERG-F overestimated the values of all precipitation amount-based indices (PRCPTOT, R85P, R95P, and R99P), three precipitation frequency-based indices (R1mm, R10mm, R20mm), one precipitation duration-based indices (CWD), and one precipitation intensity-based indices (RX5day). Furthermore, the IMERG-F underestimated the values of precipitation frequency-based indices (R50mm), one precipitation duration-based indices (CDD), one precipitation intensity-based indices (SDII). In terms of correlation, only five indexes have a correlation coefficient (R) > 0.5, consistent with Kling–Gupta Efficiency (KGE) value. These results confirm the need to improve the accuracy of the IMERG-F data in mountainous areas.
Density-Functional-Theory Calculations of Formation Energy of the Nitrogen-Doped Diamond Sholihun Sholihun; Hana Pratiwi Kadarisman; Pekik Nurwantoro
Indonesian Journal of Chemistry Vol 18, No 4 (2018)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (479.137 KB) | DOI: 10.22146/ijc.26785

Abstract

The geometry optimization of the nitrogen-doped diamond has been carried out by the density functional theory (DFT) calculations. We model the defective diamond of substitutional and interstitial nitrogen atoms by using a simple-cubic supercell. Atoms in the supercell are relaxed by allowing them to move so that the atomic forces are less than 5.0 × 10-3 eV/Å. We calculate the formation energy for substitutional and interstitial sites. We find that the formation energy for the substitutional defect is10.89 eV. We check the convergence of the calculation with respect to the k×k×k - Monkhorst-Pack grids. We show that the energy difference between k = 4 and 6 is very small (7.0 meV). We also check the calculations by using a 216-sites supercell and find that the energy difference is 0.10 eV. Thus, the calculations of the formation energy converge well. As for the interstitial defect, we model some possible configurations and find that the smallest formation energy is 21.88 eV. Therefore, the most stable configuration of the nitrogen-doped diamond belongs to the substitutional site.
Adsorption of Toxic Heavy Metal Methylmercury (MeHg) on Germanene in Aqueous Environment: A First-Principles Study Muhammad Rifqi Al Fauzan; Trias Prima Satya; Galih Setyawan; Imam Fahrurrozi; Fitri Puspasari; Juliasih Partini; Sholihun Sholihun
Indonesian Journal of Chemistry Vol 21, No 6 (2021)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.66902

Abstract

We perform first-principles calculations to investigate the adsorption process of methyl mercury (MeHg) on germanene with the presence of water molecules. We calculate the formation energy and density of states to determine the effect of the adsorption of MeHg on the structural and electronic properties of germanene. Our results show that MeHg is chemisorbed on germanene through a spontaneous reaction. The calculated formation energy of the system is -1.61 eV. We also carry out charge distribution and charge transfer calculations based on the Mulliken model to understand the adsorption mechanism of MeHg.
Numerical Calculation of Energy Eigen-values of the Hydrogen Negative Ion in the 2p^2 Configuration by Using the Variational Method Yosef Robertus Utomo; Guntur Maruto; Agung Bambang Setio Utomo; Pekik Nurwantoro; Sholihun Sholihun
Jurnal Fisika Indonesia Vol 24, No 1 (2020)
Publisher : Department of Physics Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jfi.v24i1.53331

Abstract

Calculation of energy eigen value of hydrogen negative ion (H − ) in 2p^2 configuration using the method of variation functions has been done. A work on H − can lead to calculations of electric multipole moments of a hydrogen molecule. The trial function is a linear combination of 8 expansion terms each of which is related to the Chandrasekhar’s basis. This work produces a series of 7 energy eigen values which converges to a value of −0.2468 whereas the value of this convergence is expected to be −0.2523. This deviation from the expected value is mainly due to the elimination of interelectronic distance (u) coordinate. The values of the exponent parameters used in this work contribute also to this deviation. This variational method will be applied to the construction of some energy eigen functions of Hv2 .
Metode Komputasi Sederhana untuk Menentukan Saddle Point Sistem Bumi-Bulan-Matahari dengan Akurat Yosephine Novita Apriati; Fendinugroho Fendinugroho; Ceacarico Imas Wasisto Nugroho; Primadana Barus; Rika Indah Lestari; Ahmad Zubair Al Kahfi; Sholihun Sholihun
Jurnal Fisika Indonesia Vol 25, No 1 (2021)
Publisher : Department of Physics Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jfi.v25i1.61782

Abstract

Saddle point pada sistem tata surya adalah koordinat dimana total percepatan gravitasi setimbang. Beberapa penelitian terkait saddle point antara Bumi dan Matahari telah dilakukan akan tetapi metode yang digunakan cukup kompleks dan membutuhkan resource komputasi besar. Pada penelitian ini dilakukan perhitungan saddle point untuk sistem banyak benda (Bumi-Matahari-Bulan) menggunakan metode sederhana namun memberikan hasil yang cukup akurat. Sistem Bumi-Matahari-Bulan didesain dalam bentuk masalah pencarian akar persamaan nonlinier. Metode yang dimaksud adalah Newton – Raphson dan Secant satu dan dua dimensi. Komputasi perhitungan saddle point dilakukan menggunakan Octave dan diperoleh nilai saddle-point sebesar 258.769,292  km dari Bumi.
Electronic-Structures Calculations of Calcium-Intercalated Bilayer Graphene: A First-Principle Study Sri Hidayati; Iman Santoso; Sefty Yunitasari; Sholihun Sholihun
Indonesian Journal of Chemistry Vol 22, No 6 (2022)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.75647

Abstract

In this study, electronic structure calculations of Ca-intercalated bilayer graphene are conducted using the density functional theory (DFT). We modeled two configurations by positioning calcium in the middle of the bilayer (M-site) and on top of the bilayer surface (T-site). Our results show that the Dirac point is shifted below the fermi level. The approximated critical temperature is 7.9 K. We then calculated the electron transfer and formation energy for each system. We found that, for the M-site, the electron transfer increased as the Ca concentration increased, while the reverse occurred for T-site. The calculated formation energies were negative, meaning that all configurations were spontaneously created. In other words, the involved reactions were exothermic.
Physical Properties of Polyvinyl Alcohol/Chitosan Films with the Addition of Anthocyanin Extract from Butterfly Pea for Food Packaging Applications Siti Khanifah; Alda Dwi Karina Legowo; Sholihun Sholihun; Ari Dwi Nugraheni
Indonesian Journal of Chemistry Vol 23, No 4 (2023)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.80946

Abstract

Composites of polyvinyl alcohol (PVA) and chitosan (CH) polymers, with the addition of anthocyanin (AN) obtained from the butterfly pea flower, were prepared using drop-casting. The composites were made by adding different concentrations of 5–40% anthocyanin with 5 wt.% PVA and 2 wt.% CH solutions (weight ratio of PVA/CH is 80:20). These polymers solution was mixed at 80 °C and dried using the drop-casting method at 25 °C for 48 h. The composites were characterized using a scanning electron microscope (SEM), Fourier-transform infrared (FTIR), ultraviolet-visible (UV–vis spectroscopy), contact angle, antibacterial properties, and food packaging applications. The morphology obtained using an SEM showed that the PVA/CH surface with AN and glycerol was smoother than that of PVA/CH. The increased absorption at a wavelength of 650–700 nm from UV-vis spectroscopy confirmed the success addition of AN. The contact angles of PVA/CH/AN and PVA/CH/GS/AN films were 15°–66°, which showed that the films were hydrophilic. The simple antibacterial test with Escherichia coli and Staphylococcus aureus showed 16 mm inhibition zone by adding AN. The test results of these characteristics show the potential for using PVA/CH/AN and PVA/CH/GS/AN composite film to be used as an excellent development food packaging material.
Co-Authors Agung Bambang Setio Utomo Ahmad Zubair Al Kahfi Alda Dwi Karina Legowo Ari Dwi Nugraheni Ayu Putri Ningsih Ayu Putri Ningsih Ceacarico Imas Wasisto Nugroho Fendinugroho Fendinugroho Fitri Puspasari Galih Setyawan Ghorby Al Fauzan Guntur Maruto Hana Pratiwi Kadarisman Harmadi Harmadi Helmi Yusnaini Helmi Yusnaini Hiroyuki Hashiguchi Hiroyuki Hashiguchi Imam Fahrurrozi Iman Santoso Juliasih Partini Marzuki Marzuki Muhammad Rifqi Al Fauzan Muhammad Rifqi Al Fauzan Mutya Vonnisa Pekik Nurwantoro Pekik Nurwantoro Primadana Barus Ravidho Ramadhan Ravidho Ramadhan Rika Indah Lestari Sefty Yunitasari Siti Khanifah Sri Hidayati Suryanto, Wiwit Syarifatul Ulfah Toyoshi Shimomai Toyoshi Shimomai Trias Prima Satya Wijayanti Dwi Astuti Yosef Robertus Utomo Yosephine Novita Apriati