Portal Jurnal Politeknik Negeri Semarang
Not a member yet
3817 research outputs found
Sort by
PERBANDINGAN PENGGUNAAN LEM POLYURETHANE DAN MORTAR TERHADAP VARIASI WAKTU IKAT TERHADAP KEKUATAN GESER PEREKAT PADA PEMASANGAN BETON RINGAN
Full text linkLightweight concrete is an increasingly popular construction material because of its lightweight and high strength, so effective adhesive technology is needed to increase the adhesion between elements. This study aims to compare the effectiveness of the use of polyurethane glue with MU 380 on the variation of bonding time and shear strength of bonding in the installation of lightweight brick concrete. In this study, tests were conducted on lightweight brick concrete joints using two types of adhesives, namely polyurethane glue and mortar. The variation of bonding time applied to the application of polyurethane glue includes 5, 10, 15, 20, 25, 30, 60, 360, 720, and 1440 minutes. Meanwhile, for mortar adhesive, the bonding time used is 5, 10, 15, 20, 25, 30, 60, 360, 720, and 1440 minutes. After the application of glue and mortar, shear strength testing was carried out to determine how well the concrete joints can withstand shear loads. The results showed that polyurethane glue produced much higher shear strength than mortar at all bonding times tested. The highest average shear strength was obtained at a setting time of 25 minutes for polyurethane glue, which was 21.85 MPa, while the average maximum strength of the mortar occurred at a setting time of 360 minutes with a value of 3.123 MPa. In addition, the shorter setting time of polyurethane glue allows for better installation time efficiency
Development of a MATLAB GUI Application for Computing Reliability Indices at an Electrical Substation
Full text linkThe reliability of power distribution systems plays a crucial role in ensuring the continuous and efficient supply of electricity to consumers. This study presents the development of a MATLAB-based Graphical User Interface (GUI) application designed to compute key reliability indices, including SAIFI (System Average Interruption Frequency Index), SAIDI (System Average Interruption Duration Index), and CAIDI (Customer Average Interruption Duration Index), specifically for electrical substations. The application was developed using MATLAB's App Designer and structured to provide an intuitive and interactive user experience. Real operational data from a 150 kV substation were utilized to test and validate the application’s functionality. The results demonstrate that the tool effectively simplifies the reliability analysis process, reduces calculation time, and minimizes the potential for manual errors. This application can serve as a practical support system for engineers and researchers in evaluating and improving the performance of electrical distribution systems
Experimental Study of the Performance of a Horizontal Axis Wind Turbine with A Flat Taper Type of 4:5 and an Outer Angle of 25° With Variations in The Number of Blades
Full text linkThis experimental study investigates the performance of a Horizontal Axis Wind Turbine (HAWT) with a flat taper 4:5 blade design and a 25° exit angle, focusing on the effect of varying the number of blades (6, 9, and 12). The turbine, with a diameter of 1.1 m and blade dimensions of 470 mm length, 110 mm top width, and 137 mm bottom width, was tested at wind speeds of 3 m/s, 5 m/s, 7 m/s, and 9 m/s in a laboratory setting. Parameters such as wind speed, turbine rotation, voltage, and current were measured to analyze system efficiency. The results indicate that blade count and wind speed significantly influence efficiency. The highest efficiency of 12.51% was achieved at 3 m/s with 9 blades, while at 5 m/s, the efficiency peaked at 3.95% with 9 blades. For higher wind speeds (7 m/s and 9 m/s), the optimal efficiency decreased to 2.03% and 0.95%, respectively, both achieved with 6 blades. The study concludes that this turbine design is most effective at low wind speeds (≤5 m/s), making it suitable for regions with similar wind conditions, such as Indonesia. The findings contribute to optimizing blade configurations for small-scale wind energy applications
Cover, Pengelola Jurnal, Dari Redaksi, Daftar Isi
No full textCover, Pengelola Jurnal, Dari Redaksi, Daftar Is
Does Managerial Ability Reduce Firms Cost of Debt? The Mediating Role of Earnings Quality and The Moderating Effect of Independent Commissioners
Full text linkThis study examines the impact of managerial ability on the cost of debt (COD). It also evaluates the role of earnings quality as a mediator between managerial ability and COD. It further explores the moderating role of the independent board of commissioners in the relationship between managerial ability and earnings quality. Using the path analysis method, this study analyzes data from the financial statements of manufacturing companies listed on the Indonesian Stock Exchange (IDX) from 2021 to 2023. This study finds that higher managerial ability will result in lower cost of debt. Furthermore, it indicates that managerial ability will increase firms’ earnings quality. This study also finds no evidence of a mediating effect in the relationship between managerial ability and the cost of debt. In addition, the independent board of commissioners fails to moderate the positive relationship between managerial ability and earnings quality. This study implies that managerial ability plays a key role in lowering cost of debt and improving earnings quality. It also suggests the need to enhance the effectiveness of independent commissioners and strengthen corporate governance practices
PENERAPAN SUMBER ENERGI TERBARUKAN LAMPU PENERANGAN TENAGA SURYA DALAM RANGKA MENDUKUNG PROGRAM DESA MANDIRI ENERGI DESA GONDANG KECAMATAN LIMBANGAN KABUPATEN KENDAL
Full text linkDesa Gondang merupakan salah satu desa yang terletak di daerah pegunungan. Desa Gondang terdiri dari lahan tempat tinggal, lahan perkebunan dan juga lahan pertanian. Mata pencaharian masyarakat Desa Gondang adalah sebagai petani di sawah serta perkebunan. Permasalahan yang dihadapi masyarakat Desa Gondang adalah masih terkendala lampu penerangan pada saat melaksanakan kegiatan pada malam hari, belum adanya lampu penerangan yang memanfaatkan teknologi panel surya untuk mendukung program mandiri energi. Metode yang digunakan untuk mencapai luaran tersebut adalah pemanfaatan teknologi panel surya sebagai lampu penerangan, pendampingan operasional perawatan dan perbaikan lampu penerangan tenaga surya. Hasil kegiatan pengabdian masyarakat ini adalah penerapan pemanfaatan teknologi panel surya sebagai lampu penerangan. Dengan terselenggaranya kegaiatan pengabdian masyarakat ini terjadi proses transfer pengetahuan mengenai teknologi panel surya antara tim pengabdian dengan pihak mitra pengabdian
PENDAMPINGAN PENINGKATAN KAPASITAS PRODUKSI DAN PEMASARAN DIGITAL PADA UMKM EKONOMI KREATIF OJI MACRAME DI SANGGAR 04/03 COKRO GRABAG MAGELANG
Full text linkPengabdian Kepada Masyarakat “Pendampingan Peningkatan Kapasitas Produksi dan Pemasaran digital Pada UMKM Ekonomi Kreatif OJI MACRAME di Sanggar 04/03 Cokro Grabag Magelang”, berdasarkan identifikasi di lapangan dapat dirumuskan beberapa permasalahan yang dihadapi diantaranya Sumber Daya Manusia UMKM Oji Macrame masih terbatas, belum kompeten untuk meningkatkan kapasitas produksinya. Pemasaran produknya belum memanfaatkan peluang potensi pasar yang luas untuk penjualannya belum menggunakan media secara online/digital. Untuk itu dibutuhkan kegiatan Pengabdian Kepada Masyarakat dengan melaksanakan pembekalan, penyuluhan, pelatihan, praktik dan pendampingan baik dalam peningkatan kapasitas produksi maupun pemasaran secara digital salah satunya dengan memanfaatkan Instagram/IG
Applying The Markowitz Model for Optimal Stock Portfolio Construction to Maximize Investor Returns in The Stock Market
Full text linkIncreased investor interest in stocks that have sustainability principles (ESG), but price fluctuations that tend to be more stable in the IDX ESG Leaders index often make investors face challenges in obtaining optimal returns. ndex IDX ESG Leaders itself consists of 30 stocks that have good Environmental, Social, and Governance (ESG) assessments, solid financial performance, and high liquidity. The results showed that the resulting optimal portfolio provided an expected return of 0.06% with a risk of 0.68%. This portfolio consists of 9 stocks, namely ASII (17.66%), BMRI (12.85%), BRPT (1.68%), CTRA (7.14%), ICBP (20.77%), POWR (29.39%), PRDA (3.76%), RAJA (3.17%), and SMSM (3.58%)
KUALITAS BIOETANOL TUAK TUBAN DARI NIRA SIWALAN (BORASSUS FLABELLIFER LINN) DENGAN METODE FERMENTASI SEBAGAI BAHAN BAKAR ALTERNATIF: Indonesia
Full text linkSaat ini di daerah Tuban Tuak siwalan (Borasuss Flabellifer Linn) hanya dimanfaatkan sebagai minuman olehkalangan muda dan tua. Padahal, Tuak siwalan (Borassus Flabellifer Linn) mengandung 36,1 mg karbohidrat yangdapat dimanfaatkan sebagai bahan baku pembuatan etanol. Penelitian ini bertujuan untuk mengetahui kadar etanoltertinggi pada Tuak siwalan (Borassus Flabellifer Linn) dengan variasi jumlah khamir (Saccharomyces Cereviceae)dan lama fermentasi. Hasil penelitian menunjukkan bahwa semakin lama waktu fermentasi maka kadar etanol yangdihasilkan semakin tinggi. Dengan memvariasikan waktu fermentasi maka diperoleh waktu fermentasi terbaik yaitu24 jam dan dengan memvariasikan jumlah khamir maka diperoleh jumlah khamir terbaik yaitu 40 gram dengan kadaretanol sebesar 96% setelah melalui proses destilasi bertingka