Performance Analysis of Open Steam Power Cycle Powered by Concentrated Solar Energy

This study aims to develop a concentrated solar receiver designed to directly generate steam for driving a steam turbine within the steam power cycle of a carbon-free system. The solar power system consists of parabolic dishes, evaporation tanks, and a steam turbine, and the experimental setup was tested on different days, analyzing the measured parameters with the EES software. Results from the investigation indicate that, under the optimal conditions with a maximum recorded temperature and pressure of 143 ℃ and 2.5 bar, respectively, and a vaporized water mass of 100 grams, the manufactured turbine achieved a maximum isentropic efficiency of 92.48% and a power of 1.76 W. Notably, the evaporation tank and the mini steam turbine demonstrated the capability to generate steam and mechanical power, respectively, without relying on conventional energy

Environmental Odor Analysis in West and East Java’s Ambient Air and Odor Reduction Using Biofilter Model

The odor affects both one’s health and quality of life. This study measures and analyzes odor concentration and odor sources in ambient air, the correlation between odor gas concentration and the hedonic scale, and the design of an odor-reduction instrument. The research commenced from February to May 2022 in the small industrial area (SIA) of Magetan Regency and compost bins of Bogor City. Data was collected through chemical analysis, and the hedonic scale was measured at four points divided into radii one and two. The concentration of odor parameters in Magetan and Bogor City is below the quality standard, while the correlation between ammonia gas concentration and the hedonic scale is low. Regarding the biofilter, its odor reduction efficiency is 35% for rotten fish, 70% for goat manure, 82% for compost waste, and 47% for chicken carcasses

Possibility of Using a Geopolymer Containing Phase Change Materials as a Sprayed Insulating Coating - Preliminary Results

Geopolymers have been known for decades and classified as inorganic polymers, characterized by high resistance to high temperatures. They can be successfully used for the thermal insulation of buildings, especially in the foamed form. The addition of phase change materials (PCMs) in such materials may also increase the heat capacity of the materials, therefore, using them for building cladding can increase the thermal comfort of the building and prevent it from overheating. This study tests the addition of PCMs to geopolymers by spraying and presents the results. Additionally, the study includes preliminary experience concerning the technology of applying these materials, along with selected test results that assess the properties of the produced coatings. The results indicate that the addition of PCMs in the amount of 15% can increase the heat capacity of geopolymer materials by about 150-180%, and the foamed geopolymer coatings produced have a thermal conductivity in the range of 0.07-0.09 W/mK

A Fake Profile Detection Model Using Multistage Stacked Ensemble Classification

Fake profile identification on social media platforms is essential for preserving a reliable online community. Previous studies have primarily used conventional classifiers for fake account identification on social networking sites, neglecting feature selection and class balancing to enhance performance. This study introduces a novel multistage stacked ensemble classification model to enhance fake profile detection accuracy, especially in imbalanced datasets. The model comprises three phases: feature selection, base learning, and meta-learning for classification. The novelty of the work lies in utilizing chi-squared feature-class association-based feature selection, combining stacked ensemble and cost-sensitive learning. The research findings indicate that the proposed model significantly enhances fake profile detection efficiency. Employing cost-sensitive learning enhances accuracy on the Facebook, Instagram, and Twitter spam datasets with 95%, 98.20%, and 81% precision, outperforming conventional and advanced classifiers. It is demonstrated that the proposed model has the potential to enhance the security and reliability of online social networks, compared with existing models

Food Waste Management Utilizing Black Soldier Fly Larvae

Food waste is a growing concern in developing countries. This study aims to implement food waste bioconversion by utilizing black solider fly larvae for two eateries' food waste. The bioconversion process used 0.5 g of black solider fly eggs for 14 days in the six bio ponds. After 14 days, the waste, larvae, and compost are separated using sieves to measure the larvae and compost production. The bioconversion process is evaluated based on bioconversion characteristics and black soldier fly larvae and compost produced. Waste Reduction Index, Fresh Matter Consumption Rate, Dry Matter Consumption Rate, Dry Matter Rate, and Efficiency of Conversion of Digested Feed evaluated the bioconversion characteristics for reduction. According to the experimental results, utilizing BSFL is adequate for food waste management, effectively reducing up to 62.6%. Simultaneously, the fresh larvae and compost are produced within a 14-day bioconversion process. The compost meets standards for the nitrogen, C/N ratio, phosphorus, potassium, zinc, and iron content (SNI 19-7030-2004)

Electromagnetic High-Frequency Transients Measurements of Some Household Devices

Voltage Transients are generated in power lines and emit both low-frequency electromagnetic fields and radio-frequency radiation. This study aims to highlight its existence and detrimental effects on human health. A comprehensive literature review is presented, encompassing studies by multiple authors exploring the topic of dirty electricity, its impact on well-being, and preventative measures. The electromagnetic spectrum analysis and measurements of both electric and magnetic fields are performed on various household appliances such as hair dryers, old televisions, blenders, heaters, toasters, vacuum cleaners, and microwaves. The findings indicates that microwaves and compact fluorescent lamps (CFL) bulbs exhibit similar spectral characteristics, with high-frequency voltage transients primarily originating from these two devices. Conversely, other appliances do not generate significant high-frequency voltage transients (HFVT). Overall, dirty electricity poses a substantial risk to human health and necessitates attention to minimize its adverse consequences

A Score-Based Evaluation Model for Rehabilitation of Existing Pumped Storage Hydropower Plant Construction

As the proportion of new and renewable energy increases, power control demands are becoming more frequent due to variability in power generation. As a complementary means against this, the pumped storage hydropower plants (PSHP) are attracting attention as energy storage systems (ESS), but it has high construction costs. Therefore, this study aims to improve the economic feasibility by developing the evaluation model of the existing infrastructure into an upper/lower dam suitable for PSHP. The concept of upper dam capacity is newly defined, and the evaluation index is constructed using normalization. A new evaluation system is presented for five factors: environment, stability, energy, capacity, and economy. Finally, it is tested in the pilot area in Korea. Several candidates, including the PSHP in operation, are found to have been distributed with higher scores. These results will help to satisfy the selection of candidates during the preliminary feasibility study phase, and programming them will enable more accurate and rapid assessment

Simulation Study on a New Hybrid Autonomous Underwater Vehicle with Elevators

This study aims to design a new hybrid twin autonomous underwater vehicle (HTAUV) consisting of dual cylinder hulls and analyze its pitching motion. The kinematic model for the HTAUV is established, followed by the execution of hydrodynamic simulation CFD of the HTAUV using Ansys Fluent. These simulations are conducted to obtain the hydrodynamic force equation of the HTAUV, which relates to the deflection angle of the elevator. Through the motion simulation of the HTAUV, under the same net buoyancy condition, notable differences emerge when the elevator is deflected. Specifically, parameters such as gliding speed, gliding angle, and pitch angle of the HTAUV are larger when the elevator is deflected, as compared to cases where no deflection is applied

Research and Development of Environmental Monitoring Alarm and Automatic Flag Control System for Barracks

This paper proposes a real-time flag alarm system that can monitor air quality and automatically plant colored flags to inform the people in the barracks. This system automatically measures the local PM 2.5 concentrations with PM sensors; and automatically measures the temperature and humidity with temperature and humidity sensors, then converts the measured values into the grades of danger coefficients and the grades of AQI to plant or replace flags by automatic control. The danger coefficient grades are represented by four colored flags, namely, green, blue, yellow, and red; meanwhile, the AQI grades are represented by six colored flags, namely, green, yellow, orange, red, purple, and maroon. Moreover, this system displays all measured data and related information with electronic billboards to provide a reference for people participating in outdoor activities

Optimization of SM4 Encryption Algorithm for Power Metering Data Transmission

This study focuses on enhancing the security of the SM4 encryption algorithm for power metering data transmission by employing hybrid algorithms to optimize its substitution box (S-box). A multi-objective fitness function is constructed to evaluate the S-box structure, aiming to identify design solutions that satisfy differential probability, linear probability, and non-linearity balance. To achieve global optimization and local search for the S-box, a hybrid algorithm model that combines genetic algorithm and simulated annealing is introduced. This approach yields significant improvements in optimization effects and increased non-linearity. Experimental results demonstrate that the optimized S-box significantly reduces differential probability and linear probability while increasing non-linearity to 112. Furthermore, a comparison of the ciphertext entropy demonstrates enhanced encryption security with the optimized S-box. This research provides an effective method for improving the performance of the SM4 encryption algorithm