Portal Jurnal Politeknik Negeri Semarang
Not a member yet
3817 research outputs found
Sort by
Fracture and Failure Analysis of Wheel Bolt on Main Landing Gear CN235 220M Aircraft
Full text linkThe wheel bolt of the CN235 220M aircraft is a type of fastener crucial for maintaining air pressure within the tire. It was discovered that this component fractured during operation. This study aims to conduct forensic analysis on the mechanism and causes of material failure through micro and macro morphological observations, chemical composition tests, microstructural analysis, and hardness testing on the fractured bolt. Micro-morphology results showed a crack tip in the initiation zone, which became a stress concentration point. Additionally, striations caused by cyclic loading were observed. EDS analysis revealed a high oxygen content in the initiation zone, indicating a corrosion-assisted crack. As cyclic loading continued, it gradually eroded the bolt's cross-sectional area until the material's fatigue led to final fracture
PENDAMPINGAN PERBAIKAN LANTAI KERAMIK UPAYA PENINGKATAN KEAMANAN DAN KENYAMAN PROSES PEMBELAJARAN MI HUDALIL MUTTAQIEN KEDUNGPANAS: PENDAMPINGAN PERBAIKAN LANTAI KERAMIK UPAYA PENINGKATAN KEAMANAN DAN KENYAMAN PROSES PEMBELAJARAN MI HUDALIL MUTTAQIEN KEDUNGPANAS
No full textThe quality of education is not only determined by the curriculum and teaching methods, but is also influenced by the physical condition of the learning environment, including the comfort and safety of the classroom. MI Hudalil Muttaqien Kedungpanas is one of the elementary schools that deals with problems with physical facilities, especially damaged ceramic floors in several classrooms. This damage has an impact on disrupting the teaching and learning process, and has the potential to pose a safety risk to students and teachers. This community service program aims to improve the quality of learning facilities by repairing damaged ceramic floors. The method of implementing the activity includes a survey of initial conditions, preparation of technical plans, Procurement of materials, to the repair process which is carried out in stages in accordance with civil engineering principles. The results of the community service that have been carried out show that floor repairs have succeeded in creating a more comfortable, safe, and suitable classroom environment for learning activities. In addition to improving aesthetics and safety, these repairs also have a positive impact on student learning motivation. This community service activity confirms that adequate physical facilities are an important factor in creating a quality educational environment and supporting an optimal learning process
Spiritual Values and Accounting Practices of Christian Charity Organizations: What is their Role and Meaning?
Full text linkThe Christian Charity Organization is dedicated to establishing social networks and cultivating trust among its followers through activities rooted in Christian values, demonstrating transparency and accountability to God, donors, management, and members. This qualitative case study aims to unveil the influence of spiritual values on the accountability practices within the organization. Data collection involves interviews, document analysis, and observation, followed by a thorough analysis process. The findings highlight that values such as awareness, dignity, meaningfulness, transcendence, truth, peace, and wisdom instill confidence in the organization's accountability towards God, donors, management, and members. The study sheds light on the vital role of accounting practices in public organizations for fostering societal trust. However, limitations include the case study method and the focus on the Christian Charity Organization. Future research should consider phenomenological or ethnographic approaches and encompass diverse identities within nonprofit organization
RANCANG BANGUN DIAGNOSTIC POCKET UNTUK PEMANTAUAN NON-INVASIF SPO2, BPM DAN SUHU TUBUH BERBASIS IOT DENGAN SENSOR OPTIK DAN INFRAMERAH SECARA REAL-TIME
Full text linkThis portable diagnostic device based on IoT is designed to monitor three vital health parameters: blood oxygen saturation (SpO2), heart rate (BPM), and body temperature. The system utilizes the MAX30102 and MLX90614 sensors integrated with an ESP32 microcontroller. Measurement results are displayed on an OLED screen and transmitted online to a cloud database to enable remote monitoring. The device was tested by comparing its measurements with standard instruments such as a pulse oximeter and a thermogun to validate its accuracy. Test results showed a minimum error rate of 0% and a maximum of 3.4%, with average errors of 1–2% for SpO2, 0–3.4% for BPM, and 0–2.7% for body temperature. Overall, this device proves to be an effective portable solution for personal health monitoring, offering reliable accuracy and cloud-based data storage capabilities
Perbaikan Kualitas Daya Listrik Pemakaian Sendiri PLTA Wlingi Melalui Implementasi Kapasitor Bank dan Filter LC: Studi Simulasi Peningkatan Faktor Daya dan Reduksi Harmonisa pada Sistem Pemakaian Sendiri PLTA Wlingi
No full textKualitas daya listrik menjadi aspek penting dalam mendukung keandalan operasi sistem pembangkit khususnya pada sistem Pemakaian Sendiri (PS) PLTA Wlingi. Penelitian ini difokuskan pada upaya peningkatan faktor daya dan penanggulangan harmonisa yang timbul akibat dominasi beban induktif. Berdasarkan hasil simulasi sistem eksisting, diperoleh nilai faktor daya sebesar 0,49 dengan kandungan harmonisa mendekati ambang batas standar. Solusi yang diterapkan adalah pemasangan kapasitor bank berkapasitas 317,66 kVar, disertai dengan penambahan filter pasif L-C yang dituning pada orde ke-9 untuk meredam resonansi harmonik. Hasil simulasi menunjukkan bahwa solusi ini mampu meningkatkan faktor daya menjadi 0,83 dan menurunkan nilai THD tegangan hingga 2,21%. Strategi ini terbukti efektif secara teknis dalam meningkatkan efisiensi sistem dan memenuhi batasan kualitas daya sesuai IEEE Std 519.
Kata kunci: kualitas daya, faktor daya, harmonisa, kapasitor bank, filter L-C, PLTA Wling
The Analysis and Evaluation of The Performance of 7 Stage Centrifugal Compressor Apparatus with Variations in Blade Speed and Flow Rate
No full textCentrifugal compressors have an important role in industry because they function to increase gas pressure through the impeller. However, efficiency and power consumption issues frequently arise, particularly under variations in blade speed and flow rate. Previous studies have mostly employed CFD simulations without direct experimental analysis of blade speed and valve opening on actual compressor performance. This study aims to analyze the performance of a seven-stage centrifugal compressor with variations in blade speed and flow rate through experimental methods to obtain efficient operating conditions. The research method involved collecting data three times with variations in blade speed and valve openings of 50%, 75%, and 100%, and analyzing isentropic efficiency based on motor power. The results showed the highest efficiency of 67% occurred at 550 RPM with a 50% valve opening, while efficiency decreased at 100% valve opening across all RPM levels. Motor power consumption increased from 35 Watts at 450 RPM to 280 Watts at 1350 RPM, but the increase in power was not accompanied by an increase in efficiency, especially at high speeds, which led to turbulence and decreased performance. In conclusion, the optimal compressor performance was achieved at medium blade speeds with partial valve openings, resulting in optimal efficiency and power consumption. These findings can serve as a reference for the design and operation of centrifugal compressors to achieve more energy- and cost-efficient performance
EXPERIMENTAL AND NUMERICAL STUDY RETROFITTING BEAM WITH EXPANSION IN THE SUPPORT AREA
Full text linkRetrofitting is one way to strengthen a building to withstand earthquakes and is often called an earthquake-resistant structure. Retrofitting beams will increase strength, stiffness, and ductility so that the structure is still stable when experiencing large earthquake forces. In addition to experimental methods, numerical methods are also used by researchers in developing a study of the behavior of building structures. Numerical methods using finite element software can examine the behavior of strength, stiffness, and ductility in beams. With this background, the author conducted a study of the retrofitting behavior of beams that were widened in the support area using numerical methods and theoretical analysis. The purpose of this study has been achieved so that a conclusion can be given that retrofitting with widening in the beam support area can increase the beam capacity quite significantly. Based on numerical research, with wide expansion reinforcement in the cross-sectional dimensions, the beam strength is increased by almost 45% and the beam stiffness is increased by 13-40% while ductility does not show a significant difference. These results are also expected to show the same behavior in experimental testing so that it will strengthen this reinforcement method. Experimental and numerical testing will be conducted in this study so that it will maintain the results and it is hoped that they can be accepted and practiced in the world of building construction
TINJAUAN PENGARUH PENAMBAHAN SERAT POLYPROPYLENE DAN PEMANFAATAN BETON ULTRA HIGH PERFORMANCE TERHADAP KETAHANAN ABRASI BETON
Full text linkConcrete is a material that is widely used in the construction process, proven in various sectors widely used such as foundation construction, building structures, road pavements and water channels. However, concrete still has many weaknesses in abrasion resistance. To improve the quality of concrete abrasion resistance, the addition of Polypropylene fibers and the use of Ultra High Performance Concrete (UHPC) can be used. The fibers used in the study used Polypropylene fibers and the compressive strength of concrete with the UHPC method was planned to be more than 80 MPa. Mix planning was carried out using the American Concrete Institute (ACI) method with adjustments from trial and error. Furthermore, testing was carried out and test data was obtained which will be continued with the analysis and discussion process to draw conclusions. This study is intended to test the abrasion resistance of UHPC concrete with the addition of 0.2, 0.4, 0.6 polypropylene fibers, with the pressurized water spray method at the age of 28 days. The test results showed 0.351%, 0.284%, 0.369%
ANALISIS KESELAMATAN LALU LINTAS DI AREA SIMPANG BAWEN
Full text linkSimpang Bawen area connects Semarang with surrounding cities such as Salatiga, Surakarta, and Yogyakarta. Between 2017-2023, 98 accidents were recorded starting from Hortimart Agro Center to Simpang Exit Tol Bawen. This study aims to analyze the characteristics of traffic accidents, contributing geometric and operational design factors, and recommendations for safety improvements. The in-depth analysis method in qualitative descriptive research was used with accident data from the Semarang Police Traffic Unit and supporting data from the Central Java-Yogyakarta National Road Implementation Center. Field surveys were conducted to observe location conditions. The analysis was carried out by dividing the research location into five zones. The results of the analysis showed that the most frequent accident types varied in each zone and were dominated by motorcycles and heavy vehicles. Accidents occurred in sunny weather with moderate severity and were caused by non-priority behavior. Recommendations for improvement include closing U-turns, adding rumble strips, building flyovers, installing traffic lights, enforcing traffic laws, and improving street lighting