Directory of Scientific Journals Indonesian Society of Applied Science (ISAS)
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the Estimation of State of Charge for 4S2P Lithium-Ion Battery Using Kalman Filter and Coulomb Counting: Comparative Simulation-Based Study with Evaluation of RMSE, MAE, MAPE, and R² Metrics
No full textState of Charge (SoC) estimation is crucial for the performance and safety of Battery Management Systems (BMS). This study evaluates and compares two SoC estimation methods—Kalman Filter and Coulomb Counting—based on numerical simulation of a 4S2P lithium-ion battery charging process using MATLAB. The methods are assessed using statistical metrics: RMSE, MAE, MAPE, and R², and are compared against both current-based reference calculations and normalized actual voltage. Kalman Filter consistently demonstrates superior performance, achieving lower RMSE (0.00067) and MAE (0.00045) against SoC reference, and RMSE (0.0376), MAE (0.0312), R² (0.978) against voltage reference. In contrast, Coulomb Counting shows increased error accumulation and lower correlation with system behavior. This confirms Kalman Filter\u27s robustness in dynamic conditions, owing to its real-time correction mechanism and noise tolerance. The study highlights Kalman Filter as a more accurate and reliable method for modern BMS applications. Recommendations for future development include real-world testing and hybrid algorithm implementation
Perencanaan Struktur Pemecah Gelombang dengan Sisi Miring pada Kawasan Pesisir ULPLTU Sumbawa
Full text linkThe coastal area of ULPLTU Sumbawa, located in Labuhan Kertasari, Taliwang District, West Sumbawa Regency, is affected by coastal erosion caused by shoreline retreat and wave action. Therefore, the objective of this research is to design a breakwater structure with inclined sides to mitigate the height of incoming waves. In this study, the data used includes primary data through direct field observations, while secondary data consists of wind data, tidal data, topographic data, and bathymetric data. Data processing methods involve wind data analysis, fetch, wave characteristics, bathymetry, and topography. After analyzing all the data, the breakwater structure was planned. The resulting design comprises a mound-type breakwater made of tetrapods and natural stones. It has a slope of 1:1.5 (33.7°), a crest width of 3.7 m, a crest elevation of 3.86 m, a structure height of 5 m, with the main armor layer unit weight W=4,079 kg, the second armor layer weight W/10=544.8 kg, and the core armor layer weight W/200=27 kg. Based on the results of the planning of the breakwater structure, it has been recommended to use local materials to reduce costs and support the local economy by ensuring the quality of materials according to standards. This solution is not only cost-efficient but also environmentally friendly, contributes to environmental conservation, and provides significant economic benefits to the surrounding community.Kawasan pesisir ULPLTU Sumbawa yang berada di Labuhan Kertasari, Kecamatan Taliwang, Kabupaten Sumbawa Barat merupakan salah satu lokasi yang terkena dampak dari erosi pantai yang disebabkan oleh mundurnya garis pantai yang dikombinasi dengan aksi gelombang. Sehingga tujuan penelitian ini adalah perencanaan bangunan pemecah gelombang dengan sisi miring untuk meredam tinggi gelombang datang. Pada penelitian ini, data yang digunakan ialah data primer melalui observasi langsung kondisi di lapangan, sedangkan data sekunder berupa data angin, data pasang surut, data topografi, dan batimetri. Metode pengolahan data menggunakan metode analisis data angin, fetch, gelombang, batimetri dan topografi. Setelah menganalisis semua data, selanjutnya merencanakan bangunan pemecah gelombang. Hasil dari perencanaan, didapatkan bangunan pemecah gelombang dengan tipe gundukan puing dari tetrapod dan batu alam mempunyai kemiringan 1:1,5 (33,7°) dengan lebar puncak 3,7 m, elevasi puncak 3,86 m, tinggi bangunan 5 m, berat unit lapis lindung utama W=4.079 kg, lapis lindung kedua W/10= 544,8 kg, lapis lindung inti W/200=27 kg. Berdasarkan hasil perencanaan struktur pemecah gelombang, direkomendasikan penggunaan material lokal untuk mengurangi biaya dan mendukung perekonomian setempat dengan memastikan kualitas material sesuai standar, solusi ini tidak hanya efisien dari segi biaya tetapi juga ramah lingkungan, berkontribusi pada pelestarian lingkungan, dan memberikan manfaat ekonomi yang signifikan bagi masyarakat sekitar
Pengaruh Penambahan Fly Ash Terhadap Nilai Koefisien Permeabilitas Tanah Lempung Organik
Full text linkThe role of soil is very crucial and is always closely related to infrastructure development. This is because soil functions as the basis for building construction, serving to receive and support the structural loads placed on it. In high rainfall weather conditions, the surface of the slope is susceptible to landslides. Landslides occur due to excessive water infiltration, causing the soil to become weak and collapse. To prevent landslides, efforts need to be made to reduce soil infiltration or permeability. The purpose of this study was to determine the characteristics of the addition of Fly Ash to the permeability of organic clay soil and to determine the optimum composition of the addition of Fly Ash to reduce the permeability coefficient value. The addition of variations in the percentage of Fly Ash was 8%, 16%, and 24% with a curing period of 3 days, 14 days, and 28 days. The test results obtained with the addition of 24% Fly Ash resulted in a decrease in the permeability coefficient value of 84.08% against untreated soil. It can be concluded that the use of Fly Ash can be used as a soil stabilization material, especially in permeability testing.Peran tanah sangat krusial dan selalu terkait erat dengan pembangunan infrastruktur. Ini dikarenakan tanah berfungsi sebagai dasar konstruksi bangunan, bertugas untuk menerima dan menopang beban struktural yang ditempatkan di atasnya. Pada kondisi cuaca curah hujan tinggi permukaan lereng rentan terhadap kelongsoran. Kelongsoran terjadi karena infiltrasi air yang terlalu besar sehingga menyebabkan tanah menjadi lemah dan longsor. Untuk mencegah terjadinya kelongsoran maka perlu dilakukan upaya untuk memperkecil infiltrasi atau permeabilitas tanah. Tujuan penelitian ini untuk mengetahui karakteristik penambahan Fly Ash terhadap permeabilitas tanah lempung organic dan mengetahui komposisi optimum penambahan Fly Ash untuk memperkecil nilai koefisisen permeabilitas. Penambahan variasi persentase Fly Ash ialah 8%, 16%, dan 24% dengan masa peram 3 hari, 14 hari, dan 28 hari. Hasil pengujian yang didapat dengan penambahan 24 % Fly Ash menghasilkan penurunan nilai koefisisen permeabilitas sebesar 84,08% terhadap tanah untreated. Dapat disimpulkan penggunaan Fly Ash dapat digunakan sebagai bahan stabilisasi tanah terutama pada pengujian permeabilitas
Analisis Pengaruh Perputaran Modal Kerja Terhadap Profitabilitas Pada Perusahaan Makanan Dan Minuman Yang Terdaftar Di Bursa Efek Indonesia: (Studi Kasus Pada PT. Mayora Indah Tbk)
Full text linkAbstract
This research was conducted to determine the effect of working capital turnover on profitability at PT. Mayora Indah Tbk. This study uses simple linear regression analysis method to ascertain the direction of the relationship between independent variables and dependent variables, whether it has a positive or negative relationship, and to predict the value of the dependent variable when the value of the independent variable experiences an increase or decrease using the formula Y = a + bX. The results of this study, based on simple linear regression testing, indicate that working capital turnover negatively affects profitability, as well as the t-test, indicating that working capital turnover does not have a significant effect on profitability.
Keywords: Working Capital Turnover, Profitabilit
Sistem Input Output Inventaris Tools Menggunakan Long Range RFID Study Case di PLTA Sutami
No full textThe problem faced by Sutami Hydroelectric Power Plant in the management and data collection of tools is that the data collection is still done manually, and some tools are not returned to their place due to negligence in use. To support the achievement of the 5S culture (Seiri, Seiton, Seiso, Seiketsu, Shitsuke) at Sutami Hydroelectric Power Plant, an automated tools management system is needed. In the application of the goods input and output system, many are still using low frequency RFID with a reading range of >5cm so that tapping must be done with an RFID Reader. This still has the potential for an unrecorded loan process if the item is not tapped. This research optimizes the tools management system with long range RFID. With the designed update, it is expected that the tools management system at Sutami Hydroelectric Power Plant can provide increased productivity and also achieve the 5S culture at Sutami Hydroelectric Power Plant
ANALYSIS OF DAMAGE TO RDT POWERROC T50 USING FOULT TREE ANALYSIS (FTA) METHOD
Full text linkRDT (Rock Drill Tools) Powerroc T50 is a heavy equipment widely used in the mining industry for drilling operations. Damage to this tool reduces productivity and increases maintenance costs, making a systematic analysis essential to pinpoint root causes and devise preventive measures. This study employs the Fault Tree Analysis (FTA) method to evaluate damage in the RDT Powerroc T50. The FTA facilitates hierarchical mapping of cause‐effect relationships leading to system failure. Data were gathered through direct observation, technician interviews, and review of maintenance reports and damage records. The analysis reveals 14 distinct causes for damage in the rod drill section and 7 causes in the shank adapter. Common forms of damage—fractures, wear, and cracks—are largely attributed to factors such as tool fatigue and inadequate monitoring of the machine’s life limit during maintenance. Insights from the FTA-based approach provide a systematic framework for identifying damage origins and implementing targeted mitigation strategies, thereby enhancing tool performance, reducing downtime, and lowering long-term maintenance expenses
Modifikasi Sudut Masuk Impeller Pompa Sentrifugal Untuk Mengurangi Efek Kavitasi
Full text linkA centrifugal pump utilizes pressure energy, which is generated by the kinetic energy of involute impeller rotation. A common issue in pump operation is cavitation, a physical phenomenon that occurs when the static pressure of the fluid drops below its saturation pressure, causing the fluid to boil. This phenomenon affects the pump, leading to problems such as shockwaves and erosion, which must be minimized. This research aimed to investigate the influence of pump impeller modifications in reducing the cavitation effect using the computational fluid dynamics (CFD) method. The modifications focused on adjusting the inlet and outlet angles of the pump impeller. A 3D CFD model was developed using OpenFOAM, a CFD software tool, and the cavitation number (Ca) was used as the primary parameter to measure cavitation levels. Additionally, Ca was compared to a reference cavitation number, calculated based on the saturated pressure, while cavitation points at the impeller inlet and outlet were visualized using Paraview software. The results showed that a pump impeller with a blade inlet angle (β₁) of 21,69° resulted in 39.157 cavitation points, whereas modifying β₁ to 38,66° reduced the cavitation points to 32.778, thus decreasing the cavitation points by 6.379. This confirmed that modifying β₁ significantly reduces the cavitation effect.Pompa sentrifugal memanfaatkan energi tekanan yang dihasilkan oleh energi kinetik dari putaran impeller berbentuk involute. Masalah umum dalam operasi pompa adalah kavitasi, yaitu fenomena fisik yang terjadi ketika tekanan statis fluida turun di bawah tekanan saturasinya, sehingga menyebabkan fluida mendidih. Fenomena ini memengaruhi pompa dengan menimbulkan masalah seperti gelombang kejut dan erosi, yang harus diminimalkan. Penelitian ini bertujuan untuk menyelidiki pengaruh modifikasi impeller pompa dalam mengurangi efek kavitasi menggunakan metode dinamika fluida komputasi (CFD). Modifikasi dilakukan dengan menyesuaikan sudut masuk dan keluar pada impeller pompa. Model CFD 3D dikembangkan menggunakan OpenFOAM, sebuah perangkat lunak CFD, dan angka kavitasi (Ca) digunakan sebagai parameter utama untuk mengukur tingkat kavitasi. Selain itu, Ca dibandingkan dengan angka kavitasi referensi yang dihitung berdasarkan tekanan saturasi, sementara titik-titik kavitasi pada bagian masuk dan keluar impeller divisualisasikan menggunakan perangkat lunak Paraview. Hasil penelitian menunjukkan bahwa impeller pompa dengan sudut masuk bilah (β₁) sebesar 21,69° menghasilkan 39.157 titik kavitasi, sedangkan modifikasi β₁ menjadi 38,66° mengurangi titik kavitasi menjadi 32.778, sehingga menurunkan jumlah titik kavitasi sebanyak 6.379. Hal ini mengonfirmasi bahwa modifikasi β₁ secara signifikan dapat mengurangi efek kavitasi
Bimbingan dan Pelatihan Konten Sosial Media pada UKM “Jajanan Bian” Kota Malang untuk Meningkatkan Penjualan
Full text linkSocial media nowadays is a marketing tool that supposed to be had by business owners because we can say that almost all people, especially in Indoneisa is social media active users, so if the business owner needs to be able to communicate with the target market or customers, it is highly recommended for them to optimize the use of social media. Though, there is a problem that usually faced by the small and medium enterprises that is lack of human resources and limited skill and knowledge about social media marketing, so by having this program, it is expected that in the future the SME can maximize the use of their social media platforms. The method applied in this activity of community service is doing training and mentoring with the business owner as the one that designs and plans her company marketing strategy. By having all the activities, it is found that the inconsistency in uploading and traditional content writing make the social media communication lack of engagement, so in conclusion finding customers behavior in using social media and creating a more life-connected experience content can create more interest for the customeMedia sosial saat ini merupakan salah satu alat pemasaran yang sudah seharusnya dimiliki oleh para pemilik usaha, karena bisa dikatakan hampir semua orang, khususnya di Indonesia merupakan pengguna aktif media sosial, sehingga jika pemilik usaha ingin berkomunikasi dengan target pasar atau pelanggan, sangat disarankan untuk mengoptimalkan penggunaan media sosial. Namun, ada masalah yang biasanya dihadapi oleh para pelaku usaha kecil dan menengah yaitu kurangnya sumber daya manusia dan terbatasnya keterampilan dan pengetahuan tentang pemasaran media sosial, sehingga dengan adanya program ini, diharapkan kedepannya para pelaku usaha kecil dan menengah dapat lebih mengoptimalkan penggunaan platform media sosial yang mereka miliki. Metode yang diterapkan dalam kegiatan pengabdian masyarakat ini adalah dengan melakukan pelatihan dan pendampingan kepada pemilik usaha sebagai pihak yang merancang dan merencanakan strategi pemasaran perusahaannya. Dari seluruh kegiatan yang dilakukan, ditemukan bahwa ketidakkonsistenan dalam mengunggah dan penulisan konten yang masih tradisional membuat komunikasi di media sosial menjadi kurang menarik, sehingga kesimpulannya adalah menemukan perilaku pelanggan dalam menggunakan media sosial dan membuat konten yang lebih life-connected experience dapat menciptakan ketertarikan bagi pelanggan
Analisis Biaya Pekerjaan Timbunan Tanah Dengan Metode Photogrammetry
Full text linkRecently, the construction industry has rapidly developed technology, particularly in infrastructure construction. One alternative is Free and Open Source Software (FOSS) Photogrammetry to factor in the cost of landfill work on the Padang – Sicincin toll road project. The photogrammetry method is a science and part of the art of obtaining mathematically precise measurements. The photogrammetry method can be an alternative solution for increasing cost effectiveness in projects with direct cost calculations. Surveyors conduct data measurement in the hoarding work for each layer of the Padang - Sicincin toll road project. Then, in the field, there was an inaccuracy in the x, y, z results when data was collected using a total station. According to the analysis results, the volume of the fill material deviated by 5.4%. The photogrammetry method indicated a difference of 26.95 m³ more than the manual method. The cost deviation from the previously calculated volume results was Rp2,234,719.26, making the photogrammetry method cheaper than the manual method.Contoh altenatif yakni Free and Open Source Software (FOSS) Photogrammetry kefaktor biaya pekerjaan timbunan tanah pada proyek jalan tol Padang – Sicincin. Metode Photogrammetry ialah ilmu serta seni agar mendapatkan pengukuran secara tepat melaui cara matematis. Metode photogrammetry dapat menjadi alternatif solusi dalam peningkatkan efektifitas biaya pada proyek dengan perhitungan biaya langsung. Pada setiap pekerjaan penimbunan layer jalan pada proyek jalan tol Padang - Sicincin dilaksanakan proses pengambilan data ukur oleh surveyor. Kemudian Pada aktual di lapangan terjadi ketidakakurasian hasil x,y,z saat dilaksanakan pengambilan data mempergunakan total station. Maka berdasarkan hasil analisis penelitian terdapat deviasi volume sebesar 5,4% dimana pada metode photogrammetry memiliki selisih 26,95 m3 lebih banyak dibandingkan dengan metode manual. Adapun deviasi biaya dari hasil perhitungan volume yang didapatkan sebelumnya, yakni pada metode photogrammetry sebesar Rp2.234.719,26,- lebih terjangkau dibandingkan dengan metode manual
Evaluasi dan Re-Mapping APAR di Lingkungan Gedung Perkantoran PLN UID Jawa Timur
Full text linkThis research aims to evaluate and re-map the Portable Fire Extinguishers (PFE) in the office buildings of PLN UID East Java. The method employed is a descriptive observational approach, gathering primary data through direct observation and structured interviews, supplemented by secondary data from document reviews. The findings reveal a gap between fire safety standards and actual conditions, such as improper PFE placement, unclear expiration dates, and an uneven distribution of PFE across buildings. Risk analysis identifies hazards from these issues, including delayed fire response and potential failure of PFE during emergencies. Calculating PFE needs based on Permenakertrans Regulation No. 04/MEN/1980 and NFPA-10 edition 2022 generates recommendations for redistributing PFE. Based on these calculations, three buildings (C, F, I) are found to have an excess of 13 PFE, while four buildings (A, B, D, E) are short by 9 PFE. The recommendation suggests transferring 11 PFE from Building F: 4 PFE to Building A, 3 PFE to Building B, and 2 PFE each to Buildings D and E. This redistribution ensures the correct number of PFE in each building, enhancing fire safety management in PLN UID Jawa Timur office buildings. This action aims to align the PFE distribution with safety requirements.Penelitian ini bertujuan untuk mengevaluasi dan memetakan ulang Alat Pemadam Api Ringan (APAR) di gedung perkantoran PLN UID Jawa Timur. Metode yang digunakan adalah pendekatan deskriptif observasional, mengumpulkan data primer melalui observasi langsung dan wawancara terstruktur, yang dilengkapi dengan data sekunder dari tinjauan dokumen. Temuan tersebut mengungkapkan adanya kesenjangan antara standar keselamatan kebakaran dan kondisi sebenarnya, seperti penempatan APAR yang tidak tepat, tanggal kadaluwarsa yang tidak jelas, dan distribusi APAR yang tidak merata di setiap gedung. Analisis risiko mengidentifikasi bahaya dari masalah ini, termasuk keterlambatan respons kebakaran dan potensi kegagalan APAR selama keadaan darurat. Menghitung kebutuhan APAR berdasarkan Peraturan Permenakertrans No. 04/MEN/1980 dan NFPA-10 edisi 2022 menghasilkan rekomendasi untuk redistribusi APAR. Berdasarkan perhitungan ini, tiga gedung (C, F, I) ditemukan memiliki kelebihan 13 APAR, sementara empat gedung (A, B, D, E) kekurangan 9 APAR. Rekomendasi tersebut menyarankan untuk memindahkan 11 APAR dari Gedung F: 4 APAR ke Gedung A, 3 APAR ke Gedung B, dan 2 APAR masing-masing ke Gedung D dan E. Redistribusi ini memastikan jumlah APAR yang tepat di setiap gedung, meningkatkan manajemen keselamatan kebakaran di gedung-gedung kantor PLN UID Jawa Timur. Tindakan ini bertujuan untuk menyelaraskan distribusi APAR dengan persyaratan keselamatan