EAI Endorsed Transactions on Sustainable Manufacturing and Renewable Energy

An Aerodynamic Performance Analysis of E387 and S1010 Turbine Blade Profile

2025-03-18T15:32:23+00:00

This paper investigates the changes in lift and drag coefficients, as well as the lift-to-drag ratio, of two airfoils designed for small wind turbines operating at low Reynolds numbers. The results include 2D simulations performed using the commercial software ANSYS Fluent 2019. The two selected airfoils, EPU-E387 and EPU-S1010, are newly developed and have not yet been studied for their aerodynamic performance. The research method involves varying the angle of attack to determine the optimal angle and identify which airfoil offers greater stability. The Reynolds numbers applied in the 2D simulations include 50,000, 60,000, 90,000, and 120,000. The simulation results indicate that the EPU-E387 airfoil achieves the highest lift-to-drag coefficient at the optimal angle of attack, which is 13.13% greater than that of the EPU-S1010 airfoil at Reynolds number 120,000. Additionally, the EPU-E387 airfoil demonstrates greater stability compared to the EPU-S1010 at higher angles of attack.

A Study on dyeing ability of cotton fabric 100% with naphthaquinone extracted from nipa coconut shells

2025-06-12T08:05:50+00:00

Natural dyes are known widely thanks to friendly properties to environment as health protecting ability for human. In this study, naphthaquinone of nipa coconut shells extracted by the reflux method that created effectively. The influences of ratio of dye extract, temperatures and time of dyeing and types of mordants based on the color strength (K/S) and color difference (DE) were studied. Our study applies the methods of extracting colorants in ethanol solvent, dyeing on an infrared dyeing machine, Mesdan by the exhaust dyeing method, measuring color on an X-Rite Color i5 spectrometer machine, analyzing effecting parameters by CIELab popular color space, and measuring Fourier-transform infrared (FTIR) spectroscopy to evaluate the presence of naphthaquinone in dye extract and bonding on fabric, testing more scanning electron microscopy (SEM) to observe the surface of dyed samples clearly. As results, the Nipa fruticans shell extract can dye 100% cotton fabric with a color difference ∆E of 41.07 and a K/S color strength of 12.96 when dyed with 10% CuSO₄.7H₂O because of their complex formation with the colorant with cellulose. Color fastness to washing on dyed cotton samples according to the ISO 105 – C06 A1S and ISO 105-X12 standard were tested to clarify further impacts of mordants to dye ability.

FEM-Based Analysis of Interference Fit for High-Precision Mechanical Assemblies

2025-04-27T02:18:02+00:00

This study presents an interference fit study that supports the design and evaluation of press-fit assemblies. The simulation model is based on the Thick-Walled Cylinder Theory (TCT) to accurately predict contact pressure, pressing force, and stress distribution during assembly and disassembly. The shaft-bearing assembly is machined with high precision for experimentation. The results show good agreement between the FEM simulation and the theoretical stress distribution, confirming the mechanical behavior of the interference fit. Experimental verification of the pressing force is also performed and compared with the simulation, showing consistent trends. The simulation model helps evaluate the assembly performance in different tolerance and coefficient of friction domains, providing a practical solution for high-precision mechanical assemblies.

Evaluation of a 3D-Printed Exoskeleton for Reducing Lower Back Muscle Load in Tomato Greenhouse Applications

2025-04-28T07:02:23+00:00

Lifting and carrying tasks are known to increase the risk of work-related musculoskeletal disorders, particularly in the lower back region. This study aims to evaluate the effectiveness of a 3D-printed prototyping exoskeleton (RPE) in reducing the strain on lower back muscles during the transport of fruit boxes in a tomato greenhouse. A 3D-printed exoskeleton was designed and tested, with participants performing tasks such as lifting, carrying, and lowering heavy objects on tomato farms. The evaluation involved comparing muscle activity with and without the exoskeleton intervention. Muscle activity data were collected from 15 participants, focusing on the erector spinae (ES), latissimus dorsi (LD), anterior deltoid (AD), and medial deltoid (MD) muscles. The results demonstrated that using the exoskeleton significantly reduced the load on back muscles by 55.65% to 63.55% during lifting. Additionally, during carrying tasks, the exoskeleton reduced the load on the anterior deltoid muscle by 7.00% to 8.61%. The RPE also effectively decreased rectus femoris activity during dynamic lifting and carrying tasks, potentially alleviating pain and discomfort and reducing the risk of developing back-related disorders.