Publikasi Universitas Mercu Buana
Not a member yet
7303 research outputs found
Sort by
Heat transfer and pressure characteristics of Tri Ethylene Glycol/water and Ethylene Glycol/water mixtures in copper pipe heated flow systems
No full textEnhancing heat transfer efficiency and pressure regulation in copper pipe flow systems is crucial for advancing modern cooling and heating technologies, particularly given the widespread use of copper piping in these applications. This study investigates the thermal and hydraulic performance of ethylene glycol/water (EG/water) and tri ethylene glycol/water (TEG/water) mixtures as working fluids in copper pipe systems. A series of controlled experiments was carried out on a dedicated copper pipe test section to evaluate the effects of varying flow rates on the heat transfer coefficient and pressure drop for each fluid mixture. The results indicate that the TEG/water mixture yielded a ~2.0% increase in heat transfer coefficient and a ~1.0% reduction in pressure drop compared to the EG/water mixture, with a corresponding increase in Reynolds number of approximately 37.0%. The reduction in pressure drop is primarily attributed to the lower viscosity of the TEG/water fluid. These findings provide valuable comparative insights into the thermophysical behaviour of both glycol-based mixtures and offer practical guidance for optimizing the selection of thermal fluids in large-scale cooling and heating systems that utilize copper piping
A review of rock slope failures in Malaysia: Exploring types, cases, causes, and consequences
No full textRock slope failures remain a significant concern in regions of Malaysia with varying geological formations. This review examines the challenges posed by these incidents and addresses key knowledge gaps. By providing a comprehensive, multidisciplinary analysis of case studies, technological advancements, climate influences, disaster management, and socio-economic impacts, it offers valuable insights for researchers, engineers, and policymakers. It examines key failure types, including rock falls, slides, avalanches, and general failures, through notable case studies such as Bukit Lanjan (Selangor), Kinta Valley (Perak), and Mount Kinabalu (Sabah). A comprehensive methodology framework was employed, utilizing manual search techniques (handpicking, snowballing, citation, and reference tracking) alongside advanced keyword-based searches with Boolean operators in Scopus, ScienceDirect, and Google Scholar databases. Findings reveal that Malaysian rock slopes are highly susceptible to collapse due to heavy rainfall, human activities, and natural events such as earthquakes. While these factors can act independently, their combined effects significantly amplify failure risks, particularly during intense rainfall. The consequences extend beyond immediate casualties, injuries, and property damage, leading to infrastructure failures, economic disruptions, and environmental degradation. This review underscores the need for sustainable mitigation strategies to address these risks and highlights the urgency of implementing effective solutions to safeguard lives, infrastructure, and ecosystems
Effect of curing temperature on the soil physical and mechanical properties on clay shale geopolymer fly ash stabilization
No full textClay shale is an easily degraded mudrock when exposed to weathering. The reduced strength due to degradation can be mitigated through soil stabilization. In recent years, soil stabilization using geopolymers has become one of the latest popular methods due to its economic benefits and lower carbon footprint. A widely used cementitious material for this method is fly ash-based geopolymer. The relationship between curing temperatures and the performance of clay shale stabilized with fly ash-based geopolymer has yet to be studied for the purpose of identifying a more effective stabilization method. In this study, clay shale was stabilized using geopolymer. The geopolymer was made of fly ash and an activator. Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) as activators. The activator is diluted with water to create a 12 M mixture. Before the unconfined compressive strength test, the specimens were subjected to various curing temperatures from 26oC to 60oC. The test result shows that, in general, higher curing temperatures increased the dry density from 1.66 g/cm3 to 1.84 g/cm3. Meanwhile, the unconfined compressive strength multiplies about 3.5 times. Furthermore, the moisture content decreased after the curing process from 19% to 2.5%. This led to the specimen volume experiencing decrement due to the shrinkage during the curing period. The volume reduces from 67.7 cm3 to 63.5 cm3. In general, temperature plays a significant role in enhancing the strength of clay shale stabilized using fly ash-based geopolymer
Positioning of quality systems in lean manufacturing: integrated approach vs independent implementation in the food industry
No full textDespite the widespread adoption of Lean Manufacturing (LM), its effectiveness in the food industry remains underexplored, particularly regarding the integration of the Quality System (QS). The purpose of this research is to compare QS placement and LM implementation strategies in the food industry. This study utilized a comparative approach, analyzing empirical data from four food processing companies in Indonesia over six months, employing qualitative methods (expert interviews, document analysis) and quantitative analysis. Response Surface Methodology (RSM) with the Box-Behnken design was applied for optimization, while Principal Component Analysis (PCA) identified key variables influencing Lean Manufacturing success. Two implementation strategies were compared: phased implementation with a separate Quality System (Companies A and B) and simultaneous implementation with an integrated Quality System (Companies C and D). The findings revealed that Company A achieved the highest performance, with 88% in 5S and 85% in Just-In-Time (JIT), followed by Company B with 80% in JIT and 75% in 5S. In contrast, companies C and D exhibited lower performance. PCA results indicated that PC1 (80.40%) was associated with on-time delivery and sales growth, whereas PC2 (14.47%) was linked to rejection factors. Companies A and B excelled in PC1, while Companies C and D were more dominant in PC2. These findings suggest that phased implementation of LM tools is more effective than simultaneous application. This research not only addresses a critical gap in the literature but also provides practical insights for food industry practitioners seeking to enhance operational efficiency through Lean Manufacturing
Symbolism in contemporary mosque architecture discourse: an integrative literature review
No full textContemporary mosque architecture, as part of postmodern architecture, is an interesting focus of discussion, which has dimension of subjective meanings represented or symbolized in the architectural design. Thus, this can be viewed as a medium of communication between architects and the public, or in the context of mosque architecture, as a medium for conveying Islamic teachings to the ummah. To understand how design symbolism communicates ideas in architecture, selected publications on contemporary mosque architecture were reviewed within the postmodern architectural paradigm. This study aims to critically develop new ideas and perspectives from contemporary mosque architecture as a communication medium of religious values and teachings. Using integrative literature review as methodology, the result is the construction of new ideas and perspectives regarding the relationship among aspects in the paradigm of postmodernism developed in mosque architectural history
Evaluation of the Performance of Corroded Concrete with Bottom Ash and Bacteria using Resistivity and Impact Echo Techniques
No full textConcrete is a significant contributor to global emissions, necessitating the development of environmentally friendly alternatives. This study explores the use of reinforced concrete (RC) incorporating industrial by-products, specifically bottom ash (BA), as a partial sand replacement to address this issue. Additionally, the study examines the potential of Bacillus subtilis bacteria to enhance the self-repair capabilities of corroded RC with BA. Concrete mixtures with 10%, 20%, and 30% BA were prepared and subjected to accelerated corrosion for 48, 96, and 168 hours. The corroded RC specimens were then tested for compressive strength, flexural strength, corrosion rate, non-destructive testing (NDT) methods, and SEM analysis. NDT methods included impact echo (IE) and resistivity techniques. Results showed that increasing BA content led to a decrease in corrosion resistance, with current measurements of 2.07, 1.64, and 1.47 amperes for 10%, 20%, and 30% BA, respectively. After 168 hours of corrosion, the IE frequency of the Bacillus subtilis-treated specimens was 2561.04 Hz, the lowest among all samples, while the 30% BA specimen exhibited the highest frequency at 7924.81 Hz. Resistivity measurements after 168 hours showed lower resistivity in Bacillus subtilis-treated specimens (18.25 kΩ·cm) compared to the 20% BA specimen (29.27 kΩ·cm). These findings suggest that the addition of BA and Bacillus subtilis bacteria can reduce the corrosion risk in concrete, making it a viable alternative to traditional RC
Real-time dental caries segmentation with an efficient Deformable U-Net (DU-Net) for teledentistry system
No full textDigital technology has greatly improved teledentistry by facilitating telediagnostics and teleconsultations, particularly benefiting those in remote areas. Additionally, AI advancements enhance diagnostic accuracy and streamline clinical decision-making, reducing costs and resource disparities in dental care. This study presents an improved U-Net architecture, Deformable U-Net (DU-Net), for semantic dental caries segmentation, leveraging deformable convolutions to dynamically adjust sampling points for improved feature extraction and reduced computational redundancy. By connecting encoder-decoder blocks via skip-connections, the DU-Net architecture enables efficient real-time segmentation and balance accuracy while reducing computational demands. The deformable block in DU-Net and DDR U-Net shows a balanced performance and efficiency while maintaining accuracy despite reduced FLOPs. The proposed architecture was implemented in real-time dental caries segmentation on a Dual Core Cortex A72 system and web server. It shows a significant improvement in Dice score, reducing CPU and memory usage compared to conventional U-Net models. Moreover, the DU-Net and its half variants achieved competitive performance with much lower computational demands makes suitable for web servers and embedded applications. The result highlights the DU-Net capability to optimize both computational efficiency and segmentation accuracy, offering a promising solution for real-world applications where speed and resource management are critical, particularly in the medical imaging field
Verification of a 3-Degree-of-freedom Bus Handling Model Due to Steering Wheel Input
No full textThis paper discusses about the development and modeling of a 3-DOF (Degrees of Freedom) bus handling model in response to steering wheel input from the driver. It includes all the relevant mathematical equations. The handling model was created using MATLAB/Simulink, incorporating parameters from TruckSim data to accurately represent the bus. The simulation results were verified by comparing them with TruckSim responses from two test procedures namely double lane change and single lane change tests. The comparison focuses on trends, magnitudes and percentage differences between the developed model and TruckSim results. In the double-lane change test, the largest percentage difference observed was 7%, while the smallest was 0.5% for yaw rate and longitudinal acceleration, respectively. In the single-lane change test, the largest percentage difference was 7.27% for lateral acceleration, and the smallest was 1.5% for yaw rate. The verification indicates that the simulation model closely aligns with TruckSim trends and can be effectively used for further study of bus dynamics in various scenarios
Analisis Kegagalan Mesin Filler di Industri Minuman Botol Menggunakan Metode FMEA Dan FTA
No full textProses produksi minuman botol yang dilakukan dalam jumlah yang besar memerlukan peralatan dan mesin bekerja secara terus menerus. Seiring penggunaan peralatan dan mesin, maka penurunan kinerja merupakan kondisi yang tidak dapat dihindari, sehingga peralatan dan mesin akan mengalami kerusakan (Breakdown). Salah satu mesin yang sering mengalami breakdown adalah mesin Filler. Untuk mengatasi kondisi tersebut maka dilakukan maintenance, akan tetapi maintenance yang dilakukan pada mesin Filler masih belum optimal dikarenakan downtime yang terjadi mencapai 3960 menit/tahun. Agar proses maintenance dapat berjalan lebih baik, perlu diketahui faktor utama penyebab kerusakan mesin. Penelitian ini dilakukan dengan mengidentifikasi kegagalan dengan downtime terbesar, serta menganalisis faktor penyebab kegagalan. Metode yang digunakan yaitu Failure Effect Metode Analysis (FMEA) dan Fault Tree Analysis (FTA). Hasil penelitian diperoleh Failure mode dengan RPN terbesar yaitu Putaran Bowl berat (RPN=250), as Lift Cylinder bengkok (RPN=72), Holding Belt lepas (RPN= 64) dan Kebocoran Filling Valve (RPN=96). Faktor penyebab kerusakan diakibatkan usia pakai part yang tinggi, ketelitian pemasangan part kurang baik sehingga menyebabkan terjadinya gangguan hingga kerusakan pada saat proses produksi berlangsung dan pengaturan mesin yang tidak sesuai