Article Per Year (5 Year)
p-Index From 2021 - 2026
4.848
P-Index
This Author published in this journals
All Journal Jurnal Ilmu dan Teknologi Kelautan Tropis ComEngApp : Computer Engineering and Applications Journal IJCCS (Indonesian Journal of Computing and Cybernetics Systems) ILMU KELAUTAN: Indonesian Journal of Marine Sciences Scientific Journal of Informatics Journal of Mechanical Engineering Science and Technology Jurnal Penelitian Pendidikan IPA (JPPIPA) Spektra: Jurnal Fisika dan Aplikasinya Journal of Physics and Its Applications Jurnal Kelautan Nasional Sainmatika: Jurnal Ilmiah Matematika dan Ilmu Pengetahuan Alam Jurnal Ilmu Fisika Jurnal Pendidikan Fisika dan Teknologi Eksakta : Berkala Ilmiah Bidang MIPA Jurnal Kumparan Fisika Kappa Journal Authentic Research of Global Fisheries Application Journal (Aurelia Journal) Indonesian Review of Physics (IRiP) MARLIN : Marine and Fisheries Science Technology Journal Journal of Environmental Science and Sustainable Development TECHNO-SOCIO EKONOMIKA Community Development Journal: Jurnal Pengabdian Masyarakat Zona Laut : Jurnal Inovasi Sains dan Teknologi Kelautan Indo-MathEdu Intellectuals Journal Geosfera: Jurnal Penelitian Geografi Jurnal Pengabdian Masyarakat dan Riset Pendidikan Wahana Fisika : Jurnal Fisika dan Terapannya Scientific Contributions Oil and Gas
Lulut Alfaris
Department Of Marine Technology, Politeknik Kelautan Dan Perikanan Pangandaran, Indonesia
Aerospace Engineering Agriculture, Biological Sciences & Forestry Humanities Astronomy 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 Environmental Science Health Professions Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Library & Information Science Materials Science & Nanotechnology Mathematics Mechanical Engineering Physics Public Health Social Sciences Transportation Other

Published : 39 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 39 Documents
Search

 1   2   3   4 
Heat Conduction in Cylindrical Coordinates with Time-Varying Conduction Coefficients: A Practical Engineering Approach Alfaris, Lulut; Siagian, Ruben Cornelius; Muhammad, Aldi Cahya; Nasution, Budiman
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 7, No 2 (2023)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v7i22023p157

Abstract

This research aims to develop a mathematical method for expressing the Laplace operator in cylindrical coordinates and applying it to solve heat conduction equations in various scenarios. The method commences by transforming Cartesian coordinates into cylindrical coordinates and identifying the necessary substitutions. The result is the expression of the Laplace operator in cylindrical coordinates, which is subsequently employed to address heat conduction equations within cylindrical coordinates. Various cases encompassing different initial and boundary conditions, as well as variations in the conduction coefficient over time, are meticulously considered. In each instance, precise mathematical solutions are determined and subjected to thorough analysis. This study carries substantial implications for comprehending heat transfer within cylindrical coordinate systems and finds relevance in a wide array of scientific and engineering contexts. The research's findings can be harnessed for technology development, heating system design, and heat transfer modeling across diverse applications, including mechanical engineering and materials science. Therefore, the research's contribution holds paramount significance in advancing our understanding of heat transfer within cylindrical coordinates and in devising more efficient and accurate solutions for an array of heat-related issues within the realms of science and engineering.
A Monte Carlo Density Distribution Model Study to Analyze Galaxy Structure, Mass Distribution, and Dark Matter Phenomena Nasution, Budiman; Siagian , Ruben Cornelius; Ritonga, Winsyahputra; Alfaris, Lulut; Muhammad, Aldi Cahya; Nurahman, Arip
Indonesian Review of Physics Vol. 6 No. 1 (2023)
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/irip.v6i1.8240

Abstract

This research uses the Monte Carlo density distribution model to study the structure and mass distribution of galaxies and the dark matter phenomenon. Through computer simulations, the research developed a mathematical model with parameters such as rho0, rc, beta, and others, to describe the structure and mass distribution of galaxies. The results show that the model can reproduce various galaxy structures, including groups, clusters and filaments, and influence the behavior and characteristics of individual galaxies. This research provides a deeper understanding of dark matter and its impact on the evolution of the universe. It has implications for improving our understanding of dark matter and the use of Monte Carlo density distribution models to study galaxies. This study provides new insights into the evolution of galaxies and their relationship with dark matter in cosmology. Using both physics and mathematical concepts, this research helps to understand the phenomenon of dark matter and the structure of galaxies, and provides a basis for further research on dark matter and galaxy evolution.
Distribution of Temperature and Salinity on Fishing Zone in The Regional Fisheries Management of Indonesia (WPP-RI) 573 Wahyudi, Andri; Ginanjar, Martin Anjar; Alfaris, Lulut
Indo-MathEdu Intellectuals Journal Vol. 6 No. 1 (2025): Indo-MathEdu Intellectuals Journal
Publisher : Lembaga Intelektual Muda (LIM) Maluku

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.54373/imeij.v6i1.2106

Abstract

The Fisheries Management Republik Indonesia (WPP-RI) 573 encompasses strategic waters in the southern Indian Ocean of Indonesia, playing a critical role in global ocean circulation through the Indonesian Throughflow (ITF). This study aims to examine the physical oceanographic characteristics, particularly sea surface temperature (SST), salinity, and marine ecosystem productivity in WPP 573, as well as the impacts of ITF variability on these parameters. Data utilized include SST, salinity, and current velocity obtained from satellite observations and numerical models. The analysis reveals that the ITF transports tropical water masses from the Pacific Ocean to the Indian Ocean, significantly influencing the spatial and temporal distribution of temperature and salinity in the region.
Exploring Cosmological Dynamics: From FLRW Universe to Cosmic Microwave Background Fluctuations Nasution, Budiman; Ritonga, Winsyahputra; Siagian, Ruben Cornelius; Harahap, Veryyon; Alfaris, Lulut; Muhammad, Aldi Cahya; Laeiq, Nazish
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 24 No. 04 (2023): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol23-iss04/427

Abstract

This study explores key aspects of cosmology, starting with the foundational FLRW equations that describe the universe's evolution, emphasizing its homogeneity and isotropy. We incorporate mass viscosity into these equations, shedding light on its role in shaping the universe. Observations of Type Ia supernovae inform our understanding of cosmological parameters, including the Hubble rate and dark energy's effects on cosmic expansion. Cosmic Microwave Background fluctuations are analyzed for insights into cosmic structure. Baryon Acoustic Oscillations provide additional data for estimating critical parameters. We also examine the Hubble Parameter to understand its relation to cosmological parameters. Lastly, we introduce statefinder analysis, unveiling the universe's behavior through key indicators like "r" and "s." This study offers comprehensive insights into cosmology and the universe's evolution.
Examining The Interrelationship Among Chlorophyll-A Distribution, Sea Surface Temperature Patterns, and Fishing Ground in Southern Java Sea Ginanjar, Martin Anjar; Wahyudi, Andri; Alfaris, Lulut
Indo-MathEdu Intellectuals Journal Vol. 6 No. 1 (2025): Indo-MathEdu Intellectuals Journal
Publisher : Lembaga Intelektual Muda (LIM) Maluku

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.54373/imeij.v6i1.2626

Abstract

The Southern Java Sea is vital for sustaining marine ecosystems and fisheries productivity, shaped by dynamic oceanographic processes. This research investigates the relationship between chlorophyll-a distribution, sea surface temperature (SST) patterns, and the spatial dynamics of fishing grounds in the area. Using satellite-based data from Aqua-MODIS and numerical model outputs, chlorophyll-a levels and SST variability were analyzed on 2024. Descriptive statistics and spatial analysis were applied to identify temporal trends and their connection to productive fishing zones. The results indicate a strong correlation between chlorophyll-a distribution and SST patterns, with seasonal changes significantly influencing fishing ground productivity. These findings provide critical insights for advancing sustainable fisheries management and resource planning in the Southern Java Sea. The study emphasizes the need to incorporate oceanographic indicators into fisheries policies to promote ecosystem health and economic resilience.  
Nonparametric Regression Analysis of BE4DBE2 Relationship with n and z Variables using Naive Bayes and SVM Classification on Nuclear Data Siagian, Ruben Cornelius; Alfaris, Lulut; Muhammad, Aldi Cahya; Nyuswantoro, Ukta Indra Nyuswantoro; Rancak, Gendewa Tunas
Computer Engineering and Applications Journal (ComEngApp) Vol. 12 No. 3 (2023)
Publisher : Universitas Sriwijaya

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

Abstract

This research article describes several analyses of nuclear data using various statistical methods. The first analysis uses linear regression to investigate the relationship between the independent variables (n and z) and the response variable (BE4DBE2). The second analysis uses a nonparametric regression model to overcome the assumptions of normality and linearity in the data. The third analysis uses the Naive Bayes method to classify nuclear data based on variables n and z. The fourth analysis uses a decision tree to classify nuclear data based on the same variables. Finally, the article describes an SVM analysis and a K-means analysis to classify and group nuclide data. The article presents clear and organized descriptions of each analysis, including visual representations of the results. The findings of each analysis are discussed, providing valuable insights into the relationships between the variables and the response variable. The article demonstrates the usefulness of statistical methods in analyzing nuclear data.
SOLUSI ANALITIK RESPON GERAKAN SURGE OCEAN THERMAL ENERGY CONVERSION BERBENTUK TENSIONED LEG PLATFORM (OTEC-TLP Wibowo, Yuni Ari; Riyanto, Raditya Danu; Alfaris, Lulut; Baswantara, Arif
MARLIN Vol 3, No 2 (2022): (Agustus 2022)
Publisher : Politeknik Kelautan dan Perikanan Pangandaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15578/marlin.V3.I2.2022.103-112

Abstract

Peningkatan kebutuhan energi dunia relatif mengalami peningkatan yang cukup signifikan dari tahun ke tahun. Kebutuhan akan Energi Baru Terbarukan (EBT) juga meningkat seiring dengan menurunnya cadangan energi fosil. Ocean Thermal Energy Conversion (OTEC) menajdi salah satu alternatif sumber EBT yang pengembangan teknologinya berkembang dalam beberapa dekade terakhir. Umumnya OTEC menggunakan barge sebagai struktur apung penyangganya, namun dengan bertambahnya kedalaman perairan barge menjadi tidak lagi ekonomis. Tipe struktur apung Tensioned Leg Platform (TLP) menjadi solusi pada daerah perairan dalam (>1000m). Struktur OTEC-TLP terdiri dari ponton dan kolom yang ditambatkan secara taut dengan memanfaatkan daya apung. Daya apung dari struktur ini dipengaruhi oleh perbedaan sarat air saat kondisi free floating dengan sarat air tertambat (DT). Perubahan DT akan mempengaruhi parameter hidrodinamika yang terdiri dari massa tambah, kekakuan, periode alami, gaya dan respon struktur. Studi ini dilakukan untuk mengidentifikasi pengaruh DT terhadap sensitivitas parameter hidrodinamika dengan pendekatan analitik. Persamaan Morison digunakan dalam studi analitik ini untuk menyelesaikan respon gerakan surge. Berdasakan studi yang dilakukan, semakin besar DT, menyebabkan kenaikan pada massa tambah, kekakuan, gaya dan respon struktur pada gerakan surge. Periode alami OTEC-TLP pada saat DT rendah memiliki nilai yang lebih besar dibandingkan dengan DT yang lebih besar, namun keduanya memiliki periode alami yang relatif lebih besar jika dibandingkan dengan periode gelombang dominan (2 – 30s). Kondisi ini menjadikan OTEC-TLP memiliki kondisi stationkeeping yang baik karena tidak berada pada area periode gelombang dominan.Increasing demand of energy worlwide is increasing significantly year on year. The need for New and Renewable Energy (NRE) also increases along with the decline in fossil energy reserves. Ocean Thermal Energy Conversion (OTEC) is a viable alternative sources of NRE which has been in the development process in the last few decades. In general, OTEC uses barge as its floater, however in accordance with increasing water depth, the barge becomes no longer economical. Tensioned Leg Platform (TLP) is a solution in deep water areas (>1000m). OTEC-TLP structure consists of pontoons and columns which are tethered by means of buoyancy. The buoyancy of floater is formed by the difference of drafts (DT) between tethered and free floating condition. Changes in DT will induce the hydrodynamic parameters consisting of added mass, stiffness, natural period, force and structural response. This study was conducted to identify the effect of DT on the sensitivity of hydrodynamic parameters with an analytical approach. Morison's equation is used in this study to solve the surge motion response. Based on this study, the greater DT induce the higher added mass, stiffness, force and response of the structure in surge motion. The natural period of OTEC-TLP at low DT has a larger natural period than the higher DT. However both of them have relatively larger natural periods when compared to the wave period (2 – 30s), this condition creates OTEC-TLP having a good stationkeeping responses.
PENGARUH RESPON GERAKAN TANKER PADA SISTEM TERTAMBAT CONVENTIONAL BUOY MOORING (CBM) TERHADAP VARIASI BEBAN LINGKUNGAN Wibowo, Yuni Ari; Firdaus, Anas Noor; Alfaris, Lulut
MARLIN Vol 3, No 1 (2022): (Februari 2022)
Publisher : Politeknik Kelautan dan Perikanan Pangandaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15578/marlin.V3.I1.2022.15-25

Abstract

Perkembangan sistem transfer minyak dan gas lepas pantai terapung tidak bisa dilepaskan dari perkembangan sistem tambat untuk menjaga posisi bangunan apung dalam kondisi stasionkeeping. Respon gerakan dan tension tali tambat merupakan parameter penting yang digunakan dalam merancang konfigurasi sistem tali tambat. Sistem tali tambat yang biasa digunakan pada perairan dangkal adalah sistem Conventional buoy Mooring (CBM), selain kemudahan dalam proses instalasi dan perawatan, sistem ini juga relatif lebih murah jika dibandingkan dengan sistem point mooring yang dapat berputar mengikuti arah beban lingkungannya (weathervaning). Analisis numerik pada konfigurasi tertambat CBM dilakukan untuk mengidentifikasi respon gerakan bangunan apung akibat beban lingkungan secara collinear dan non-collinear. Simulasi time domain Cummins dilakukan untuk menyelesaikan persamaan gerak tanker dan sistem tambat secara simultan. Pada analisis yang dilakukan, didapatkan respon gerakan tanker pada kondisi pembebanan non-collinear lebih dominan pada gerakan surge, sway dan pitch sebesar 82%, 10% dan 12% secara berturut-turut. Sedangkan gerakan heave, roll dan yaw, respon gerakan lebih besar ditemukan pada pembebanan collinear sebesar 3%, 64% dan 17% secara berturut-turut. Berdasarkan analisis fast fourier transform (FFT) didapatkan spectral density gerakan horizontal (surge, sway dan yaw) memiliki dua puncak, puncak pertama pada frekuensi rendah (0.00-0,10 rad/s), dipengaruhi oleh frekuensi natural sistem tertambat yang beresonansi dengan gelombang orde-2 dan puncak kedua pada frekuensi 0.30 rad/s yang dipengaruhi oleh gelombang orde-1.The development of a floating offshore oil and gas transfer system cannot be separated from mooring system development to maintain the position of the floating structure in a stationary condition. Motion responses and mooring line tensions are crucial parameters used in mooring system configuration design. The configuration of mooring system commonly used in shallow waters is the Conventional Buoy Mooring (CBM). In addition to the ease of installation and maintenance, this system is also relatively cheaper than the point mooring system, which rotates in the direction of the environmental load (weathervaning). Numerical analysis on the CBM moored configuration was carried out to identify the motion responses of the floating structure due to collinear and non-collinear environmental load cases. Cummins time domain simulation was carried out to solve motion equation of the tanker and mooring system simultaneously. This analysis generated motion response of tanker under non-collinear loading conditions was significat in surge, sway and pitch motion of 82%, 10% and 12%, respectively. While the heave, roll and yaw motion, greater response motion were found in collinear of 3%, 64% and 17%, respectively. Based on the fast Fourier transform (FFT) analysis, it found the spectral density of horizontal motion (surge, sway and yaw) has two peaks, the first peak is at a low frequency (0.00-0.10 rad/s), influenced by the natural frequency of the moored system which resonates with the 2nd order wave and a second peak at a frequency of 0.30 rad/s which is influenced by a 1st order wave.
Analysis of Solar Flux and Sunspot Correlation Case Study: A Statistical Perspective Siagian, Ruben Cornelius; Alfaris, Lulut; Nasution, Budiman; Nasution, Habibi Azka
Kappa Journal Vol 7 No 1 (2023): April
Publisher : Universitas Hamzanwadi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29408/kpj.v7i1.12238

Abstract

This analysis examines the relationship between the number of solar flares and the number of sunspots in 2005 using 11 observations in months 2 to 12. The number of solar currents measures the intensity of the radiation emitted by the Sun, while the number of sunspots measures the number of sunspots on the surface of the Sun. Multivariate linear regression analysis was used to analyze the relationship between Solar Current Rate and Number of Sunspots. The results of the analysis show that the coefficient of the Amount of Solar Current is 1.1239 with a significant t value of 2.510 (probability that there is no effect on the Number of Sunspots is 3.33%). The linear regression model has good results with an F-statistic value of 6.301 and a p-value of 0.0333, with an R-squared value of 0.4118 which indicates that 41.18% of the variation in the number of sunspots is influenced by variations in the amount of solar currents. The corrected R-squared value is 0.3464 indicating that there are still variations in the number of sunspots that cannot be explained by variations in the number of solar currents. ARIMA analysis results show an MA coefficient of 0.7351 with an average value of 45.9542 and a s.e value of 0.2590 and 6.1550 respectively. The AIC, AICc, and BIC values are 92.97, 96.4, and 94.16. The error results in the training set show that the ME value is 0.2615561, the RMSE value is 12.16969, the MAE value is 9.03306, the MPE value is -15.14689, the MAPE value is 30.42013, and the MASE value is 0.674109. The ACF1 value in the exercise set is 0.0808969.
Separation of Variables Method in Solving Partial Differential Equations and Investigating the Relationship between Gravitational Field Tensor and Energy-Momentum Tensor in Einstein's Theory of Gravity Siagian, Ruben Cornelius; Alfaris, Lulut; Nurahman, Arip; Muhammad, Aldi Cahya; Nyuswantoro, Ukta Indra; Nasution, Budiman
Kappa Journal Vol 7 No 2 (2023): Agustus
Publisher : Universitas Hamzanwadi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29408/kpj.v7i2.20921

Abstract

This research delves into the study of partial differential equations (PDEs) and gravitational fields in spacetime. It focuses on solving PDEs using the Separation of Variables method and explores the relationship between the gravitational field tensor and the energy-momentum tensor, leading to the final equation for the gravitational field tensor. The research also investigates Einstein's theory of gravity and the energy-momentum tensor integral, providing the general solution for the gravitational potential and its implications. Additionally, the mean integration of the gravitational wave tensor is analyzed, yielding an expression for the tensor strain of gravitational waves over an infinitely long period. The components of the gravitational wave tensor and their effect on gravitational sources are examined. Furthermore, the propagation of electromagnetic fields in spacetime is studied using the Retarded Green's Function. The primary objectives of this research are to understand and explore mathematical techniques for solving PDEs and analyzing gravitational fields and their interactions in spacetime. The integration of multiple theoretical concepts related to PDEs, gravitational fields, and electromagnetic fields enhances our understanding of fundamental physics principles. This contributes to the advancement of theoretical physics and opens avenues for potential practical applications, such as gravitational wave detection and electromagnetic field propagation in complex media. In conclusion, this research provides valuable insights into fundamental physics principles and fosters a deeper understanding of their interconnections and implications
Co-Authors Abdul Rahman Afriana Kusdinar Aldi Cahya Muhammad Andri Wahyudi ANDRI WAHYUDI, ANDRI Ariefka, Reza Arif Baswantara Arip Nurahman Arip Nurahman Arip Nurahman Arip Nurahman Aunzo, Jr., Rodulfo T. Budiman Nasution Dolfie Paulus Pandara Eko Pramesti Sumarto Eko Pramesti Sumarto Firdaus, Anas Noor Froilan Delute Mobo Gendewa Tunas Rancak Gendewa Tunas Rancak Ghulab Nabi Ahmad Godwin Latuputty Goldbert Harmuda Duva Sinaga Hakim, Muhammad Romdonul Harahap, Veryyon Hareva, Batih Shendy Capri Hassan, Rohana Indah Indah Karim, Mohammad Alfin Kennedi Sembiring Laeiq, Nazish Martin Anjar Ginanjar Ma’muri Ma’muri Mia Endang Sari Sinaga Nasution, Habibi Azka Nazish Laeiq Nazish Laeiq Nunik Wijayanti Nurahman, Arip Nyuswantoro, Ukta Indra Nyuswantoro, Ukta Indra Nyuswantoro Pandara, Dolfie Paulus Prayitno, Muhammad Riyono Edi Putri, Miranda Putriara Tresa Fitira Rahdiana, Nana Raihan Natawisastra Rancak, Gendewa Tunas Rikha Bramawanto Rikha Bramawanto Riyanto, Raditya Danu Ruben Cornelius Siagian Ruben Cornelius Siagian Ruben Cornelius Siagian Ruben Cornelius Siagian Ruben Cornelius Siagian Ruben Cornelius Siagian Sahroni, Taufik Roni, Mr. Sembiring, Kennedi Siagian , Ruben Cornelius Siagian, Ruben Cornelius Suhara, Ade Suhernalis Suhernalis Suhernalis Suhernalis Suhernalis Taufik Roni Sahroni Ukta Indra Nyuswantoro Ukta Indra Nyuswantoro Ukta Indra Nyuswantoro Ukta Indra Nyuswantoro Ukta Indra Nyuswantoro Wanri Lumbanraja Wibowo, Yuni Ari Winsyahputra Ritonga winsyahputra Ritonga Yasin, Verdi