Open Access

Article

Article ID: 1752

Influence of the new wavy teat liner “Stimulor StressLess” on milk yield performance and its quality in dairy cows: Results of a field study

by Shehadeh Kaskous, Khaled Al-Najjar, Michael W. Pfaffl

Mechanical Engineering Advances, Vol.2, No.2, 2024; 0 Views, 0 PDF Downloads

The ideal milking system meets the physiological needs of dairy cows to increase milk yield, achieve better milk quality and maintain healthy udders. Therefore, the settings of the milking machine and the properties of the teat cup liners are very important on dairy farms. The aim of the present study was to test a new teat cup liner “Stimulor StressLess” (SSL) in two commercial dairy farms and to investigate its influence on daily milk production and quality having different experimental settings. For this purpose, 40 dairy cows of different breeds in Tirol, Austria (farm 1) were investigated for 6 months, where 3 months represent the control phase (Gr 1) and milked with conventional teat liners, and the second 3 months phase (Gr 2) was the experimental phase and milked with SSL teat cup liners. On the second farm 90 dairy cows of Simmental breed in Baden-Württemberg, Germany (farm 2) were examined for one year equally divided in the first 6 months of control phase and second 6 months of treatment phase. All cows on both farms had the same stage of lactation and lactation number. During the study period, the daily milk production of each cow was recorded and milk samples were collected to determine the ingredients. The results showed that higher daily milk production and better milk quality were observed after using the new SSL teat cup liner in the existing milking machines. However, the use of the new teat cup liner SSL was more efficient in the longer treatment in farm 2 than in farm 1. In addition, after the use of the new SSL teat cup liner, the udders remained healthy throughout the study period, showing lower somatic cell counts (SCC). It can be concluded that high milk yield and better milk quality can be achieved by using SSL teat cup liners, as they are adapted to all teat shapes and dimensions.

Open Access

Article

Article ID: 1561

Ocean current turbine power take-off design using fluid dynamics and towing tank experiments

by Setare Sadeqi, Shahab Rouhi, Nikolaos I. Xiros, Erdem Aktosun, Lothar Birk, Juliette Ioup, Miguel Trejos

Mechanical Engineering Advances, Vol.2, No.2, 2024; 29 Views, 18 PDF Downloads

This study investigates the performance and power generation capabilities of a small-scale hydrokinetic turbine by comparing numerical simulations with experimental measurements. The key difference between the two models comes from the initial numerical analysis which focused only on the permanent magnet DC motor (PMDC) motor’s parameters and did not account for the gear-head reduction that leads to discrepancies in current and torque predictions, especially at lower input voltages. In practice, friction losses within the gear-head increased the required current and torque, highlighting inefficiencies in the motor gear-head system. A modified experimental setup incorporated a magnetic coupling to address leakage issues and enhance system reliability. While the magnetic coupling resulted in a slight reduction in speed, current, and torque, it improved the overall integrity of the system which is essential for marine applications. The comparison between experimental results and Blade Element Momentum (BEM) simulations showed good agreement at lower speeds, but the simulations under-predicted power at higher speeds, likely due to the model’s limitations in capturing complex hydrodynamic phenomena. This shows the need for comprehensive analysis, integrating both numerical and experimental approaches to optimize turbine performance. Future research will focus on refining experimental methodologies and further improving turbine design and efficiency for hydrokinetic energy systems.

Open Access

Article

Article ID: 1578

Design of optimum spacecraft reorientation control with a combined criteria of quality based on the quaternions

by Mikhail Levskii

Mechanical Engineering Advances, Vol.2, No.2, 2024; 24 Views, 16 PDF Downloads

Specifical original problem of attitude controlling for spacecraft was proposed in this paper. Problem of optimal rotation from a known initial state in a prescribed spatial orientation was studied in detail (turnaround time is not fixed). Design of optimal program of reorientation is based on new indicator of quality that combines energy costs including the contribution of controlling torques and integral of rotary energy (in a known proportion) and reorientation time; presence of duration factor bounds time of rotation finish. To construct an optimal control of angular momentum changing, quaternionic method and the maximum principle were applied. Differential equation that relates spacecraft angular momentum and quaternion of spacecraft orientation is a base to obtain analytic solution to a problem. We reveal the properties of optimum control program analytically, and study key features of optimum motion in details. Also, we write the formalized equations, mathematical formulas to design optimal law for change of spacecraft’s angular momentum. Analytic relations and equations are given for finding the optimal solution. Control law (in as explicit dependence between phase variables and con-trolling variables has been formulated. Main relations determining optimum values of parameters for rotation control algorithm were given. The closed-form law for rotation was obtained for dynamically symmetric solids. Numerical example as well as results of mathematical modeling of spacecraft motion that formed using optimum control are presented. This data as addition to the made theoretic descriptions shows reorientation process (in virtual form) and demonstrates practical feasibility of the developed control method. A designed algorithm for optimal control of rotation improves an efficiency of attitude system, and originates more economical performing of space vehicle during its flight along orbit.

Open Access

Article

Article ID: 421

Traction drive simulations when starting an electric locomotive series ŽS 444 on the railway tracks of Serbia

by Branislav Gavrilovic, Vladimir Aleksandrovich Baboshin

Mechanical Engineering Advances, Vol.2, No.2, 2024; 50 Views, 29 PDF Downloads

The manuscript presents and describes the Model in Matlab-simulink, which allows to display the time change of the firing angle of the thyristor of the single-phase rectifier, the mean value of the voltage, the armature current and the speed of the electric motor during the start-up of the electric locomotive ŽS 444 series for different given mechanically loaded and reference speeds of traction electric motors. The model makes it possible to establish the desired reference speed change ramps for different reference speeds and mechanical loads from +250 rpm, i.e., the maximum current of the electric motor armature up to 1250 A.

Open Access

Article

Article ID: 1470

Hydrogel 3D printing with direct and indirect extruder

by Thanh Tan Nguyen, Ngoc Hieu Pham, Hoang Son Tran, Le Nguyen Cao, Thi Hong Nga Pham, Quoc Bao Phan, Van Tron Tran

Mechanical Engineering Advances, Vol.2, No.2, 2024; 72 Views, 65 PDF Downloads

The advancement of additive manufacturing technology or 3-Dimesion printing (3D printing) allows for the creation of parts with intricate designs, resulting in less material waste compared to conventional manufacturing methods. Although current 3D printers primarily use plastic or metal materials, there is a growing interest in using biomaterials for 3D printing. To facilitate this trend, developing and designing 3D printers capable of using hydrogel materials is crucial. In this research, the 3D printer with direct and indirect extruders for hydrogel material is designed, calculated, and manufactured. Then, the 3D printer is tested with conductive sodium alginate 5% + 5% activated carbon by weight. In addition, the electrical conductivity of the material is measured. Through meticulous research and development, a 3D printer capable of printing hydrogel materials has been successfully manufactured, setting the stage for further exploration and the creation of environmentally friendly 3D biomedical printing materials.

Open Access

Article

Article ID: 1495

Research on tire internal defect identification method based on deep learning

by Jiaqi Chen, Aijuan Li, Te Wang, Xibo Wang

Mechanical Engineering Advances, Vol.2, No.2, 2024; 65 Views, 47 PDF Downloads

As an important part of automobile, the safety and durability of tire have attracted more and more attention. Tire defect detection is an important link to ensure tire quality, while traditional detection methods have problems such as low efficiency, high false detection rate and high labor intensity. Therefore, this study aims to develop an efficient and accurate tire defect identification and classification technique to improve the efficiency and accuracy of tire inspection. In this paper, based on YOLO (You Only Look Once) v5 algorithm, tire defect recognition and classification are studied. Firstly, the data sets containing various types of tire defects were collected and sorted out, and the data sets were preprocessed. Then, by constructing, training and optimizing the YOLOv5 tire defect recognition model, the fast and accurate recognition of tire defects was realized. Finally, the performance of the model was evaluated through experiments and compared with the existing methods. The experimental results show that the tire defect recognition and classification method based on YOLOv5 proposed in this study has high accuracy. Compared with traditional methods, this method has a significant improvement in detection speed and accuracy.