Reduced graphene oxide-ZnO hollow microsphere composite for supercapacitor applications

Through a facile solvothermal synthesis process, a reduced graphene oxide-ZnO microsphere composite was produced at 180 °C for 24 hours. Raman spectroscopy, X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy were used to analyze the morphological structures of the material. The analysis revealed that hexagonal phase wurtzite ZnO nanoparticles assembled homogeneous microspheres, decorated on the graphene sheets by graphene oxide functional groups. The ZnO nanoparticles are about 30 nm in size and the microspheres are hollow. A possible growth mechanism for the formation of ZnO hollow microspheres anchored on graphene sheets has been proposed. Cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance were used to evaluate the electrochemical performance of the composite. At a scan rate of 1 mV/s, the reduced graphene oxide-ZnO hollow microsphere composite electrode demonstrated an enhanced specific capacitance of 40.70 F/g with energy and power densities of 5.75 Wh/kg and 1.97 kW/kg, respectively

ANFIS method to enhance FMEA water operation model of Indonesia drinking water distribution system

Many problems are found in water treatment and distribution in water operations. Those problems range from low to critical risk. All critical risks must be addressed immediately. The Failure Mode and Effects Analysis (FMEA) prioritizes problems based on Occurrence, Severity, and Detection values to identify critical risks. However, this method is also having problems. With the same risk priority number (RPN) calculation, FMEA would be a ranking problem with the same RPN value; hence, we have a priority problem that is not critical but based on the highest value. To solve this problem, we propose additional methods, such as the ANFIS, to give weight based on risk level classification. From the results of data processing carried out by the ANFIS method, it is proven that it can perform re-ranking, for example, in the L2, R5, S8, and U3 code, which has an FMEA RPN value of 12. However, in FMEA-ANFIS, the RPN value becomes L2 2.05, R5 1.52, S8 1.32, and U3 2.52. Furthermore, with these results, it can be concluded that the ANFIS method can enhance the FMEA model in water operations

Signal quality comparison of customer base and branching methods in fiber to the home network design

One communication medium that is well-known for its outstanding and reliable performance is fiber optic. A social example of its application is the Fiber to the Home (FTTH) network. The goal of this study is to evaluate the signal quality of the customer base method and the branching method, two FTTH-building techniques based on the PT.PLN Icon Plus standards, in order to identify the most practical approach for use in the Air Hitam 2 cluster. Two scenarios were used in this study at the Fiber Access Terminal (FAT) with 1:16 and 1:8 splitters. The fiber optic cable path design findings demonstrate that the branching approach is a wise decision, utilizing optical fiber cables for a total of 9 Km, with the greatest cable distance being 2.5 Km from the Optical Line Terminal (OLT) to the end FAT. According to theory, in the 1:16 splitter situation and the 1:8 splitter scenario, the optical power received by the Optical Network Terminal (ONT) is -19.13 dBm and -16.03 dBm, respectively, with an OLT transmit power of 3 dBm. For these cases, the simulation results are -17.98 dBm and -20.27 dBm. Additionally, the budget value for the rising time reaches 0.253 ns. The bit error rate values in the 1:16 and 1:8 splitter scenarios are 3.157 × 10-10, and 1.63507 × 10-28, respectively, while the Q factor values are 6.18233 and 11.014, respectively. Based on theory and simulation, these findings suggest that the branching strategy can deliver good performance

Instrumented model slope to investigate the influence of rainfall and slope gradient on matric suction

Prior researchers indicated that prolonged and heavy rainfalls primarily trigger major landslides in Malaysia. This study was carried out to investigate the influence of rainfall on the matric suction of silty sand slopes through a small-scale model. A 35° and 45° slope (namely EXP1 and EXP2) models were built using soil samples from the former landslide site at Kemensah Heights, Selangor, Malaysia. Two types of sensors were used to measure matric suction and rainfall intensities using Watermarks 200SS Soil Moisture Sensor and Hydreon rain gauge RG-15, respectively. The elapsed time since the beginning of the rainfall was recorded using two cameras placed at the front and side of the slope model to observe progressive failure. The results showed that the initial matric suction with a value of 250 kPa is significantly reduced and approached 0 kPa when the range of cumulative rainfall intensity is between 30 and 36.75 mm/min and 5.25 and 6.75 mm/min recorded by PP1 and PP2 in EXP1 and EXP2, respectively. The results indicate that the reduction in matric suction induced by rainwater infiltration is the triggering mechanism of slope failure. It has also been noticed that rainfall infiltration increases with decreasing slope gradients. However, a small gradient slope requires longer rainfall prior to failure. A slope with a high gradient has a longer time before failure occurs after loss of matric suction than a low slope gradient

Five questions on the multisensory perception in historic urban areas

Multisensory perception is essential for individuals or communities to fully appreciate urban historic areas. Recognizing non-physical aspects such as sound, smell, and tactile sensations based on human senses is crucial for enhancing the relationship between individuals and their environment. Discussions on heritage conservation extend beyond physical aspects evaluated visually to encompass non-physical elements. This article presents five questions covering the definition, influencing factors, types and categories, and methods for multisensory perception research. Furthermore, this article aims to explain gaps in multisensory research in urban historic areas to determine what and how future heritage conservation studies should be conducted. The research employs content analysis methods to analyze discussions from selected literature regarding the benefits of multisensory research in urban historic areas. Multisensory perception significantly influences the diverse sensory experience of intangible aspects in an environment, enriching urban heritage conservation approaches

Experimental investigation on slope runoff, sediment, and hydraulic parameters under different underlying surface

This study utilizes a rainfall simulator to conduct an experimental investigation of slope and rainfall on various underlying surfaces. This study aimed to determine the relationship between various hydraulic factors and sediment concentration by estimating runoff, sediment concentration generation, and hydraulic parameters on various underlying surfaces. The flow velocity, flow depth, shear stress, and unit stream power are the hydraulic parameters in this experiment. The soil sample will be set up appropriately in the rainfall simulator with a slope of 20º and subjected to a rainfall event for two hours on four trays with various underlying surface types. The rainfall intensity of 10 Lmin⁻¹ was designated for the rainfall simulator. Throughout a two-hour period, the runoff flow was collected at intervals of 30, 60, 90, and 120 minutes. The measured sediment concentration using Total Suspended Solid (TSS). Then measurements were conducted of the sediment concentration, runoff discharge, and hydraulic parameters. According to the results, the stream power of the four covers is higher for the dried leaves (0.004606 ms-3), grass cover (0.003274 ms-3), gravel (0.00232 ms-³), and bare soil cover (0.00081 ms-³). But bare soil produces the maximum concentration of sediment and surface runoff, which is then followed by grass, gravel, and leaves. In general, the generation of sediment began with the bare surface, gravel, dry leaves, and grass in descending sequence. Research has shown that rain-induced plant cover can be used as a low-cost strategy to reduce soil erosion on construction slope sites.

Bibliometric analysis of research trends in rigid pavement over the last decade

This study presents a bibliometric analysis of research trends in rigid pavement over the last decade, aiming to identify publication trends, research output distribution, main themes, citation patterns, and research gaps. The PRISMA method was employed, and statistical analysis was conducted using bibliometric software. By collecting bibliographic data from academic publications, this research reveals a significant growth in rigid pavement publications, reflecting increased global interest in this field. Major research themes include pavement design, material characterization, construction techniques, maintenance, and performance evaluation. Citation pattern analysis is used to identify influential works in this field. However, this study has limitations in data coverage and is susceptible to biases inherent in bibliometric analysis. Nevertheless, it contributes significantly to understanding the research landscape of rigid pavement, providing valuable insights for researchers, practitioners, and policymakers. Future research could deepen qualitative analysis, track the evolution of research themes, and explore interdisciplinary frameworks to enrich our understanding of rigid pavements

Performance of speech enhancement models in video conferences: DeepFilterNet3 and RNNoise

As remote work and online education continue to gain prominence, the importance of clear audio communication becomes crucial. Deep Learning-based Speech Enhancement has emerged as a promising solution for processing data in noisy environments. In this study, we conducted an in-depth analysis of two speech enhancement models, RNNoise and DeepFilterNet3, selected for their respective strengths. DeepFilterNet3 leverages time-frequency masking with a Complex Mask filter, while RNNoise employs Recurrent Neural Networks with lower complexity. The performance evaluation in training revealed that RNNoise demonstrated impressive denoising capabilities, achieving low loss values, while DeepFilterNet3 showed superior generalization. Specifically, "DeepFilterNet3 (Pre-Trained)" exhibited the best overall performance, excelling in intelligibility and speech quality. RNNoise also performed well in subjective quality measures. Furthermore, we assessed the real-time processing efficiency of both models. Both RNNoise variants processed speech signals almost in real-time, whereas DeepFilterNet3, though slightly slower, remained efficient. The findings demonstrate significant improvements in speech quality, with "DeepFilterNet3 (Pre-Trained)" emerging as the top-performing model. The implications of this study have the potential to enhance video conference experiences and contribute to the improvement of remote work and online education

Verification of a 3-Degree-of-freedom Bus Handling Model Due to Steering Wheel Input

This 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

Understanding passenger satisfaction and expectations in free bus service based on socio-demographic characteristics in Johor and the Klang Valley, Malaysia

Free bus service is known to serve passengers with the same goal as normal bus does. In fact, the implementation of free bus service acts as an alternative solution for those who have financial limitations. To keep a high satisfaction level of passengers regardless of various backgrounds, it is important for the free bus providers to maintain the quality of their service. Therefore, this study aims to understand the relationship between socio-demographic characteristics and the satisfaction level and expectation of passengers on free bus services allocated in Klang Valley and Johor, Malaysia. A survey was conducted among the free bus users to collect data on their socio-demographic characteristics and their experiences with the service quality offered. According to the survey, teens and single people were the primary passengers of the free bus service. Moreover, passengers who had low income, no driving license, and no vehicles were also more likely to use the service. The overall satisfaction level of passengers was high (mean score > 3.6), indicating that the service quality provided by the free bus service provider met the expectations of passengers. However, no evidence was found from this study to relate socio-demographic factors with satisfaction level.