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All Journal POSITRON CAUCHY: Jurnal Matematika Murni dan Aplikasi Indonesian Journal of Pharmaceutical Science and Technology Jurnal Pengabdian Kepada Masyarakat (Indonesian Journal of Community Engagement) Jurnal Penelitian Pendidikan IPA (JPPIPA) Spektra: Jurnal Fisika dan Aplikasinya Jurnal Agrinika : Jurnal Agroteknologi dan Agribisnis Jurnal Geosaintek
Yudi Rosandi
Universitas Padjajaran
Aerospace Engineering Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT Decision Sciences, Operations Research & Management Earth & Planetary Sciences Education Electrical & Electronics Engineering Energy Materials Science & Nanotechnology Mathematics Medicine & Pharmacology Physics

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Antioxidant Activity of Non-Volatile Lime (Citrus aurantifolia Swingle) Extract Permadi, Nandang; Julaeha, Euis; Rosandi, Yudi; Nurzaman, Mohamad
Jurnal Agrinika: Jurnal Agroteknologi dan Agribisnis Vol 5, No 2 (2021): SEPTEMBER
Publisher : Kadiri University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30737/agrinika.v5i2.1919

Abstract

The paper reports the antioxidant activity of a non-volatile fraction of lime processing byproducts from the lime syrup home industry. The activity was measured by spectrophotometry to obtain the 50% inhibition concentration (IC50) using the 2,2- diphenyl-1-picrylhydrazyl (DPPH) method. The sample was extracted by the maceration method with n-hexane, ethyl-acetate, and ethyl-ethanol. The IC50 values of 681 ppm, 458 ppm, and 2,775 ppm were n-hexane, ethyl-acetate, and ethyl-ethanol. The experiments concluded that the ethyl-acetate extract provides the best inhibition value to scavenge free-radicals DPPH. The HPLC and mass spectroscopy were measured to find out the content and group of active compounds. The significant compounds consisted of naringin, poncirin, or neoponcirin, which are known as antioxidant substances. The result shows the potential application of the lime by-products, its volatile fraction, and the nonvolatile fraction, which is the production residue of lime peel. This work can be applied as an alternative to zero-waste lime production, which may benefit the industry and the environment.
Struktur Resistivitas Dangkal Sebagai Upaya Mitigasi Bencana Pergerakan Tanah Bambang Wijatmoko; Budy Santoso; Eleonora Agustine; Yudi Rosandi
Jurnal Pengabdian kepada Masyarakat (Indonesian Journal of Community Engagement) Vol 5, No 1 (2019): April
Publisher : Direktorat Pengabdian kepada Masyarakat Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (497.247 KB) | DOI: 10.22146/jpkm.33076

Abstract

Cisempur village is located at the slope of Mount Geulis, having a very variated morphology from gentle slopes to very steep ones. Due to the high demand for settlements the land use change can not be avoided.  The steepness of the slope, the decrease of the number of vegetations, and the increase of load from buildings may induced land slide occurrence.  This problem motivate us to perform measurement at the area, in order to uncover the information about the level of stability and the land carrying capacity, through the study of the subsurface rock layering condition. In this work, we present the shallow resistivity by means of Electrical Resistivity Tomography (ERT) method in two measurement lines. The obtained data is processed using 2D inversion method, in order to obtain the layering structure cross-section. The interpretation of the results suggest the existence of sandstone, which is normally associated with the location of aquifer and tuffaceous clay. The tuffaceous may function as the slide plane in the land slide event. The interpretation also shows that the carrying capacity decrease very extremely at the settlement site, which is indicated by the land displacement. This information has to be socialized and transferred to the inhabitant, in order to build awareness, and the land slide disaster mitigation can be carried out.
Horizontal to Vertical Spectral Ratio (HVSR) Analysis of the Passive Seismic Data on Alluvial Lithology: An Example from Bandung Basin Rim Evi Fazriati; Muhammad Randy Azhari; Abdul Hakam; Widya Utama; Yudi Rosandi
Jurnal Penelitian Pendidikan IPA Vol 9 No 1 (2023): January
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v9i1.2962

Abstract

Bandung basin is surrounded by active volcanoes at the center of Western Java region. Soil type of this area consists mostly of volcanic alluvial, formed by the past volcanic activities. At this location, we performed passive seismic surveys to reveal the sedimentary characteristics using a triaxial seismometer, to study the properties which have potential implications on environmental aspects, such as natural disaster mitigation and the city planning. In this work we reported the analysis of three component vibration signals by means of the Horizontal to Vertical Spectral Ratio (HVSR) calculation to identify the sediment thickness through the dominant frequency of the earth vibration. The method signal processing successfully revealed the amplification factor of the area, which is very important to determine the potential ground motion induced disasters. The data was collected using a laboratory developed seismic logging device with sensitivity of 0.28 ± 5% V⋅s/cm. The signal preconditioning was carried out to shape the acquired signals with high noise level, prior to the HVSR calculation. From the measurements and computation, we obtained the thickness variation at the chosen survey area of around 32 to 64 meters, corresponding to the measured dominant frequency of around 2.5 to 5.0 Hz. The results agree very well with the reference sediment thickness measured by the microtremor surveys. The vibration frequencies are also consistent with the range suggested by the literature
Protonation Process of Porous Silica Cluster Surface using Molecular Dynamics Method Alfaridzi, Raihan; Nugroho, Bintoro Siswo; Rosandi, Yudi
POSITRON Vol 13, No 1 (2023): Vol. 13 No. 1 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v13i1.63670

Abstract

Using molecular dynamic simulation, we developed an algorithm to protonate the surface of an amorphous porous silica grain particle model and study its effect. In this work, the silica grain model can be used to study cosmic dust coagulation. The surface of the silica cluster was protonated by placing H atoms on oxygen atoms having only a single bond, namely, the non-bridging oxygens. The H atoms are placed opposite the Si–O bond with a distance of around 1 Å to form silanol (Si–O–H) group termination on the silica surface. The angular conformation of the silanol was optimized by relaxing the surface at low temperature. We evaluated the number of silanol groups, the angular distribution of the Si-O-H bond, and the average distance between Si-O particles using the radial distribution function (RDF). The result of the study shows that minimizing the energy of the silica surface changes the angular distribution of the silanol from 180° to about 110° and between 140°-160°. However, the average distance between Si-O particles remains at 1 Å, which demonstrates the correctness of the atomic interaction model. The addition of protons on the silica surface is an essential factor in the simulation of cosmic dust collision since the modification of the surface chemistry may alter the contact surface energy, thus changing the probability of particle coagulation.
In-Silico Study of N-Hydroxysuccinimide Folate and GAPDH as Targeting Agents for Tuberculosis Treatment Marhaendra, Laurentius Ivan Ageng; Muchtaridi, Muchtaridi; Rosandi, Yudi; Gazzali, Amirah Mohd
Indonesian Journal of Pharmaceutical Science and Technology Vol 12 (2025): Vol. 12 Suppl. 2 (2025)
Publisher : Indonesian Journal of Pharmaceutical Science and Technology

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/ijpst.v12s2.59597

Abstract

Tuberculosis remains a major public health concern due to emerging cases of drug resistance. To overcome this issue, the effectiveness of antitubercular medications must be reinforced. One of the methods that can be used is using active targeting, which involves small molecules that bind to a specific receptor. In this research, we study the potential of N-hydroxysuccinimide (NHS) folate to be used as the targeting agent against the GAPDH (glyceraldehyde-3-phosphate dehydrogenase) cell-surface receptor, a common virulence factor found on many pathogenic bacteria, including Mycobacterium tuberculosis. We conducted this research using computational methods, specifically molecular docking and molecular dynamics simulation. Based on the evaluation of molecular docking and molecular dynamics simulation results, NHS-folate is predicted to have a huge potential to be an active targeting agent against the GAPDH receptor of Mycobacterium tuberculosis.
A Sinusoidal-Based Mathematical Model for Psychotherapy Effects in Bipolar Disorder Type 2 Patients Nursuprianah, Indah; Anggriani, Nursanti; Nuraini, Nuning; Rosandi, Yudi
CAUCHY: Jurnal Matematika Murni dan Aplikasi Vol 10, No 2 (2025): CAUCHY: JURNAL MATEMATIKA MURNI DAN APLIKASI
Publisher : Mathematics Department, Universitas Islam Negeri Maulana Malik Ibrahim Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18860/cauchy.v10i2.33537

Abstract

Bipolar Disorder (BD) is a mental disorder characterized by recurrent manic and depressive episodes. This study aims to build a mathematical model that models mood changes in BD type 2 before and after psychotherapy. Daily mood data were collected for more than 3 months from one BD patient, then divided into seven terms of 14 days each. The analysis was carried out through a sinusoidal function fitting process and numerical simulation based on the Van der Pol differential equation. The results showed that before psychotherapy, the mood amplitude reached 1.99632, the frequency was 0.4926, and the moment of inertia was 4.121081. After undergoing routine psychotherapy 9 times, the amplitude decreased to 0.635, the frequency increased to 1.052, and the moment of inertia decreased to 0.903584. The average mood was controlled at 6.492, within the normal mood range. The decrease in amplitude and moment of inertia indicated that BD mood became more stable and less easily affected by the environment, while the increase in frequency indicated a faster recovery of emotional rhythm. Conclusion: Routine psychotherapy is effective in quantitatively stabilizing the mood of BD type 2.
Analyzing the Influence of Bedrock Geometry on Ambient Vibration Using HVSR and Particle Dynamics Fazah, Hanum; Rosandi, Yudi
Spektra: Jurnal Fisika dan Aplikasinya Vol. 10 No. 2 (2025): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 10 Issue 2, August 2025
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.102.03

Abstract

Ground vibration signals recorded by low-frequency multi-channel geophones provide information about the physical characteristics of a medium. Using the passive seismic method, vibrations are measured in three channels, i.e. horizontal and vertical directions. Since the characteristics of mediums, such as sediment thickness and soil hardness, are contained in low-amplitude ambient vibrations, further data selection is required to remove spikes in the signals induced by active sources. This work is necessary to reveal the characteristics that reflect the mediums’ physical condition from the signal. Conventionally, signal processing is based on the Horizontal-to-Vertical Signal Ratio (HVSR) calculation. The information obtained, such as sediment thickness and sub-surface shear velocity (Vs30), as well as the amplification factor and seismic vulnerability, are crucial for geotechnical applications. This data can be extracted from HVSR analysis. However, a complete understanding of the complex vibration signal shape related to the medium and local geological conditions is not fully understood. To gain a deeper understanding of the mechanism, numerical modeling is performed using a particle dynamics method. The vibration pattern of chosen particles on the surface was studied and its relation to the geometry of the fixed base region was investigated. The simulation results show systematic changes in signal form when processed with a similar HVSR method as a response to the shape of the fixed base.
KARAKTERISASI LAPISAN BAWAH PERMUKAAN LERENG HASIL PERGERAKAN SESAR LEMBANG MENGGUNAKAN ELECTRICAL RESISTIVITY TOMOGRAPHY PADA SAG POND MURIL Aliyan, Silmi Afina; Susanto, Kusnahadi; Pamungkas, Totok Doyo; Ihsan, Haikal Muhammad; Harja, Asep; Fitriani, Dini; Rosandi, Yudi
Jurnal Geosaintek Vol. 11 No. 2 (2025)
Publisher : Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j25023659.v11i2.2224

Abstract

Co-Authors Abdul Hakam Alfaridzi, Raihan Aliyan, Silmi Afina Asep Harja, Asep Bambang Wijatmoko Bintoro Siswo Nugroho Budy Santoso Dini Fitriani, Dini Eleonora Agustine Euis Julaeha Evi Fazriati Fazah, Hanum Gazzali, Amirah Mohd Ihsan, Haikal Muhammad Indah Nursuprianah Kusnahadi Susanto Marhaendra, Laurentius Ivan Ageng Mohamad Nurzaman Muchtaridi Muchtaridi Muhammad Randy Azhari Nuning Nuraini Nursanti Anggriani Pamungkas, Totok Doyo Permadi, Nandang Widya Utama