Engineering Journal (Faculty of Engineering, Chulalongkorn University, Bangkok)
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Optimizing Shearing Characteristics of Sugarcane Leaves for Efficient Biomass Utilization and Machinery Design in the Sugar Industry
Get PDFSugarcane leaves, which are significant biomass residues from the globally important industrial crop, have potential as fuel sources for electricity generation. This study aimed to investigate the influence of moisture content, leaf region, and loading rate on shear strength and specific shearing energy of sugarcane leaves, focusing on the Khon Kaen 3 (KK3) cultivar. Experimental factors included four levels of moisture content (48.17%, 30.22%, 23.10%, and 8.90% w.b.), three leaf regions (lower, middle, and upper), and four loading rates (150, 250, 350, and 450 mm/min). Results showed significant impacts of moisture content, leaf region, and loading rate on shear strength and specific shearing energy (P < 0.01). The lower leaf region exhibited the highest shear strength (1.380 N/mm²) and specific shearing energy (12.184 mJ/mm²) at a moisture content of 48.17% w.b. and a loading rate of 150 mm/min. Conversely, the upper leaf region showed the lowest shear strength (0.372 N/mm²) and specific shearing energy (2.651 mJ/mm²) at a moisture content of 8.90% w.b. and a loading rate of 450 mm/min. To enhance cutting efficiency and minimize energy consumption during cutting leaves, it is recommended to sun-dry the leaves for 20-30 days before cutting to achieve a moisture content below 20% w.b. These findings could optimize cutting processes, machinery design, and agricultural practices in sugarcane harvesting and biomass utilization. This study is expected to contribute to understanding plant mechanical properties and provide insights for cutting devices and biomass processing systems. Further research should explore additional factors to advance efficiency and sustainability in the sugar industry and biomass utilization
Experimental Demonstration of Channel Routing of Microwave Signals Sharing an Optical Link by Using a Tunable Optical Band-Pass Filter
Get PDFThe imperative need to share an optical link to optimize its use among multiple users for data distribution continues to be a topic of technological challenge. In this regard, it is well known that one of the most common techniques is the WDM technology. However, this paper describes a technical alternative that enables channel routing for data sharing over an optical link between two users using a tunable Optical Band-Pass (OBP) filter. This proposal is experimentally validated. To demonstrate the viability of this approach, microwave signals are used as data. The selected microwave signal is wirelessly transmitted at the end of the optical link. The signal-to-noise ratio (SNR) parameter measure is adopted to evaluate the quality of each microwave signal, achieving an average SNR of 37.01dB. This proposal is validated for microwave signals within the S-band (2 to 4 GHz), however, this frequency interval can be expanded. Potentially, this approach allows the sharing of optical fiber among multiple users to deliver services via wireless links in indoor environments
Assessing Machine Tool Selection Process in Sustainable Production to Address Climate Change Based on Hybrid MCDM Methods
Get PDFIn recent years, there has been an increasing focus on optimizing production processes with the concept of sustainability because of the awareness of climate change around the world. Meanwhile, the machine tool is a crucial component of the manufacturing process. Therefore, this research aims to evaluate the process of machine tool selection in production with a concentration on reducing carbon dioxide emissions. Through the integration of different Multi-Criteria Decision-Making (MCDM) methods, including the Analytic Hierarchy Process (AHP), Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), and Evaluation based on Distance from Average Solution (EDAS), a mathematical model is proposed to make the best choice for machine tools. According to the AHP method, the motor output of the main spindle holds the most significant weight in the evaluation criteria, making it the most important factor to consider. The selection of the ideal machine tool is determined through the TOPSIS and EDAS methods. After careful evaluation, the CKQ 6136 CNC lathe has been identified as the optimal choice, as it scored the highest assessment value in both TOPSIS and EDAS methods. This study contributes to environmentally responsible manufacturing practices by considering machine tool selection, sustainability, and climate change mitigation
Silver Nanoparticles/Skim Natural Rubber/Bacterial Cellulose Biopolymer Film
Get PDFThe accumulation of non-degradable wastes is a significant threat to ecosystems and living organisms, necessitating urgent action to mitigate their environmental impact. This paper presents the synthesis and fabrication of green and biodegradable composite films with antimicrobial properties from silver nanoparticles, skim natural rubber (SNR), and bacterial cellulose (BC). BC was cultivated using organic agricultural waste and then was modified through immersion in silver nanoparticles synthesized within SNR latex. Characterizations of BC-SNR-Ag biopolymeric composites such as silver nanoparticle dispersion, mechanical strength, thermal stability, water absorption capacity and antibacterial properties were investigated. The results showed that the concentration of silver nitrate influenced the production and the diffusion of silver particles into the BC matrix. Furthermore, compared to pure BC film, the inclusion of SNR and silver nanoparticles significantly enhanced the properties of the composites in terms of flexibility and antibacterial properties
Development of Automated System for Classifying Productivity Behavior of Construction Workers Using Deep Learning
Get PDFIn Japan, the integration and comprehensive understanding of data related to the working environment and productivity at construction sites remain underdeveloped. This study introduces a system that utilizes the human activity recognition method, employing accelerometers combined with deep learning techniques, to capture a detailed overview of activities performed by construction site workers. We developed a new approach for transforming accelerometer data collected from devices attached to workers’ helmets into a format suitable for image-based analysis. This data was then processed using a convolutional neural network to create a deep-learning model capable of distinguishing between different types of worker movements. The model demonstrated high accuracy, with correct classification rates of 80.0% for walking and 92.1% for forward-leaning postures—activities commonly observed at construction sites. Additionally, we established an ensemble system to enhance the final classification of productive motions. This innovative system holds the promise of enabling future quantification of on-site productivity through daily indices that reflect workers’ engagement levels
Improving Aggregate Abrasion Resistance Prediction via Micro-Deval Test Using Ensemble Machine Learning Techniques
Get PDFAggregate is the most extracted material from the world's mines and widely used in civil and construction projects. The Micro-Deval abrasion test (MD) is one of the most important tests that provides characteristics of crushed aggregates that show their resistance against mechanical abrasive factors such as repeated impact loading. The impact of various factors on abrasive resistance properties of aggregates has led researchers to seek correlations, often focusing on limited data samples, leading to reduced accuracy. This study employs machine learning (ML) methods to predict MD abrasion values, considering diverse aggregate properties. Various ensemble ML methods were applied, revealing the exceptional performance of the stacking model, which achieved an R2 score of 0.95 in predicting aggregate abrasion resistance. The feature importance analysis highlights the influence of factors such as Magnesium Sulfate Soundness (MSS), Water Absorption (ABS), and Los Angeles Abrasion (LAA) on aggregate abrasion values, suggesting that the use of multiple test methods could yield a more dependable assessment of aggregate durability
Biomechanical Analysis of Scoliosis Adjusted by Screw Fixation System with Finite Element Analysis
Get PDFAdolescent Idiopathic Scoliosis is the most common type of scoliosis. The popular scoliosis treatment is scoliosis bracing or surgical treatment. The Cobb method is generally used to measure the scoliosis curvature angle for the surgeon in order to plan the treatment process. In addition, the Cobb angle of 40 degrees often creates a difficulty for surgeons in selecting the suitable treatment for the patients because the Cobb angle of 40 degrees is, in general, indicated as too large for scoliosis bracing although is not large enough to be indicated for surgical treatment. Therefore, this research investigated the relationship between the deformity of the Cobb angle between 30-70 degrees adjusted by the screw fixation system and evaluated the maximum equivalent of total strain distribution on the 3D models using the finite element analysis. All model cases were calculated with nonlinear ligament forces. The result showed a correlation between larger Cobb angles with higher maximum equivalent of total strain occurred on the vertebra, mainly resulted from the Rebound Force. The larger Cobb angle has resistance from the tendon and the muscles against the restoring force of the fixation devices adjusting the curvature of scoliosis. For this reason, the scoliosis patients with small Cobb angle are advised to be treated with surgery before the Cobb angle reaches 70 degrees in order to reduce the risk of damage on the vertebra, the fixation device, and the unsuccessful result of surgery
Smart Mushroom Cultivation House: Engineering Development and Data Analysis
Get PDFThis paper presents the engineering development of the smart mushroom cultivation house and the time-series analysis of the collected data. The cultivation house is located at the School of Agricultural Resources, Chulalongkorn University, Nan province and the experimental work has been done in June-July 2023. An automatic humidity control system, which consists of water pump, fog nozzles, water flow sensor, temperature-humidity sensor (AM2301), relay-push button board and LCD display, is developed. It is controlled by C/C++ program stored in the microcontroller board (NodeMCU ESP8266 V3). The system is specifically designed for smart mushroom cultivation. The NETPIE 2020 platform is adopted for data collection, real-time monitoring, and parameter adjustment via the web application. Temperature, humidity, pump state, and water flow volume are monitored and recorded. After this development, Japanese cone mushrooms and oyster mushrooms have successfully developed fruiting body in this cultivation house. Time-series analysis of the recorded data shows that the developed system has advantages in terms of labor, water and electrical power consumption as compared with the typical method for growing mushrooms in a cultivation house
Management and Utilization of Fly Ash Containing High Free-Lime and Sulfur Trioxide Contents
Get PDFThis study focuses on managing fly ashes with elevated free lime and sulfur trioxide contents, which are produced at a coal-fired power plant. Two techniques are employed for this purpose. The first technique involves pre-combustion, where correlations between coal and fly ash properties are established to estimate the properties of the resulting fly ash. Statistical analysis was performed on six years' worth of data on coal and fly ash properties provided by the power plant, including coal ash and fly ash analyses, to establish these correlations. These relationships not only help to produce fly ash with desired properties but also help to separate, collect, and manage the off-standard fly ash with undesired properties. The second technique is a post-combustion approach, specifically fly ash blending. An extensive experimental program was conducted to investigate the effects of blending high-free lime fly ash with low-free lime fly ash to be able to utilize the fly ash with high free lime content in the concrete industry. Three types of fly ashes were derived from 2 sources, and free lime was added up to increase the free lime content in these fly ashes. Subsequently, six blended fly ashes were prepared by mixing low and high-free lime fly ashes to evaluate their properties. Various tests, including water requirement, setting times, compressive strength, autoclave expansion, expansion due to alkali-aggregate reaction, and sulfate expansion, were conducted on the blended fly ash mixtures. When compared with the results of a previous study, the performance of the mixtures with the blended fly ashes fell between those of the mixtures containing high and low-free lime fly ashes. This finding indicates that the blending technique holds promise in addressing the issue of high-free lime fly ash effectively
Understanding the Force Deflection Behavior of NiTi Archwire at Distinct Bending Configuration: A Narrative Review in Vitro Studies
Get PDFThis study aims to assess the optimal unloading force range for human comfort by considering NiTi archwires in different bending settings, based on previous research findings. All the relative data has been collected from different databases such as PubMed, Google Scholar, Scopus, Web of Science, and USM library. The publications from 2007 till February 2023 have been incorporated. Several parameters related to orthodontics, especially the usage of three brackets and three-point bending with respect to optimal tooth force were taken into consideration. These parameters, however, included various aspects like the shape memory effect, bending temperature, friction, and gingival/labial direction. ISO standards pertaining to the bending tests were also contemplated in this review. The study examined 74 articles related to orthodontic tooth movement, three brackets, and three-point bending. In fact, this review was done to analyze the force deflection behavior and related parameters to orthodontics. For this, among 74 selected research items, 15 studies gave information about the optimal tooth force, 8 focused on the optimal ranges, while 7 reports indicated the higher rates of tooth force. All these studies illustrated the considerable variation in methodology and clinical diversity in terms of applied forces. This article summarizes previous investigations on orthodontic tooth force, highlighting the ideal range of 0.2 to 1.5 N. It concludes that maximum force decreases with greater inter-bracket distance but increases with wire deflection and testing temperature. Proper force management is emphasized as crucial for preventing unwanted tooth movement and its biological consequences