UTEHY Journal of Science and Technology

DYNAMIC CHARACTERISTICS ANALYSIS FOR CLAW ROTOR OF VACUUM PUMP WITH CONSTANT AND VARIABLE LEADS

2023-12-07T11:02:14+07:00

The dynamic characteristics and lead function of a conjugated rotors are the key influences on twin-screw rotor vacuum pump performance. However, the relationship between two factors is lacking in previous studies. Therefore, this study proposes a method for analyzing dynamic characteristics between two rotors of vacuum pump with constant and variable leads. The mathematical model of generated rotor profile based on the sealing line is applied to generate the 2-D rotor profile. And then the rotor surfaces with constant and variable leads are constructed. The dynamic characteristic of meshing rotors is evaluated by using the Adams software. The influence of dynamic characteristic of rotor pair on the function of rotor lead has been analyzed. The numerical examples are verified the merit of the constructed model.

INFLUENCE OF DOUBLE PULSE CONDITION ON WELDED SIZE AND TENSILE STRENGTH IN PULSE MIG WELDING

2023-12-07T11:02:22+07:00

In aluminum and aluminum alloys welding, alternating current has an effect of breaking an aluminum oxide film and cleaning the surface for better weld formation. The Aluminum and aluminum alloys have high thermal conductivity; thus, a process of controlling the weld pool size plays an important in ensuring the weld quality. Some factors influencing the shape of the weld pool can be due to the type of welding current, pulse condition... In which, an application of the MIG DOUBPULS function has a significant influence on the shape and quality of the weld. In this study, aluminum alloy A5052 and A6061 were welded by MIG welding process under changing pulse modes including pulse frequency Hz, time ratio and current ratio at pulse pin and pulse peak, using Er5356 welding wire with established welding current, voltage and speed. Results show that with changing the pulse mode, tensile strength as well as weld shape and size change. As the pulse frequency increases the penetration depth (h) and the weld width (b) decreases and then increases, while the weld height (c) increases and then decreases. The b and h increases, c decreases with an increase in the time ratio or current ratio at the pulse pin (%Tmin) and pulse peak (%Imin). The tensile strength of the welded samples is about 67.9 % to 88.8 % of the base metal tensile strength.This result will be a basis for making recommendations in aluminum and aluminum alloys welding by equipment with the MIG DOUBPULS function.

DESIGNING A FOUR-BALL FRICTION MACHINE CONTROL SYSTEM TO EVALUATE THE LUBRICANT QUALITY OF OIL AND ADDITIVE MIXTURE

2023-12-09T08:48:04+07:00

In the field of science and technology, friction and wear are always important issues of concern and research. Choosing a suitable lubricant for the working conditions of a machine is one of the factors that helps ensure the working conditions and life of the machines. This article describes the design of a control system for a four-ball friction machine to evaluate the lubricant quality of industrial oil and fly ash additives. Fly ash is used as an additive to increase the viscosity of lubricant oil mixtures. The results show that the scratch width tends to decrease when the additive content increases from 0 % to 0.75 %, then increases sharply at higher additive ratios. When the additive ratio is too high, the ash particles do not disperse evenly on the friction surface, leading to uneven wear and increasing scratch width. The research results provide a basis for selecting suitable lubricants and additives for machines under established working conditions.

BUILDING A MODEL OF SYSTEM TO AUTOMATICALLY SEPARATE PRODUCT FROM MOLD USING PLC S7-300

2023-12-09T09:35:21+07:00

In this paper, we present a model monitoring control system that automatically separates the product from the mold using PLC S7-300 and monitoring on HMI. The system is built based on the theoretical research analysis method and the actual system, thereby providing the optimal plan for the calculation and selection of equipment. The completed system has been reported and successfully deployed in teaching and scientifc research for lecturers and students at the Faculty of Electrical and Mechanical Engineering, Hai
Phong University. From this system, readers can develop to build a large system model that can be applied in industry, serving production activities at foundries, mechanical processing.

DETERMINATION AND COMPARISON OF THE QUALITY CHARACTERISTICS BETWEEN THE TWO SLUB YARNS WITH SAME BASE YARN COUNT BUT DIFFERENT SLUB PATTERNS

2023-12-09T10:09:51+07:00

This paper presents the study of determination and comparison of the real yarn count, yarn count unevenness, yarn twist, yarn twist unevenness, yarn breaking force, yarn breaking force unevenness, yarn hairiness between two slub yarns with same base yarn count Ne10, but with diﬀerent slub patterns. The study results show that the slub patterns aﬀect the slub yarn quality through yarn quality characteristics such as the yarn breaking force, the yarn count unevenness and the yarn hairiness. The smaller the slub multiplier (or slub pattern), the higher the above slub yarn quality characteristics.

STUDY ON SOME CHEMICAL TREATMENTS OF BANANA FIBER FOR SPINNING

2023-12-09T10:26:48+07:00

Banana fber is one of long and strong natural fbers, possessing many superior properties (such as water resistant, antimicrobial, fre retardant, wrinkle resistant…) similar to those of ﬂax, jute, ramie & cotton fbers, so it can be completely de-gummed, softened, combed and spun to be used in haute couture, decorative, furniture and industrial products. However, after being stripped and decorticated, the banana fber still contains lot of pectin & lignin, so it is rough, dark colour and has limited spinnability. This article studies and compares two typical processes of scouring-bleaching banana fber by chemical method. The research team has carried out two options of scouring-bleaching process: 1. Scouring-bleaching banana fber in diluted solution of H2O2 5% in combination with NaOH 4%, liquid ratio 1:20, at 95 oC during 30 minutes; 2. Scouring-bleaching banana fber in diluted solution of H2O2 5% in combination with Na2SO3 2%, liquid ratio 1:20, at 95 oC during 30 minute. The testing results of tensile strength, whiteness index, and weight loss show that alkali treatment separated banana fber bundles into smaller bundles and single fbers. The best results were obtained by the option 2: fber tensile strength loss, fber whiteness index were equivalent to those of the option 1 but the degumming eﬀect (fber weight loss) was considerably higher compared to the option 1.

DESIGN AND CONTROL OF 3 DOFs ROBOT MANIPULATORS IN JOINT SPACE

2023-12-09T10:49:21+07:00

This paper presents the steps to design and test a system control in joint space applies for a robotic manipulator with 3 degrees of freedom (DOFs) based on independent control method. The control object is the joint of the robot that creates motion by the actuators of the DC motor.Content includes: modeling of manipulators, sewing materialsOperate, calculate and design a classic PID controller with three feedback loops of position, velocity and acceleration. Use Matlab/SIMULINK software to simulate and verify the results according to the standards of accuracy, stable operation and fast processing speed required for the method.

STUDY ON STABILITY FOR LONGITUDINAL POWER SYSTEM BY USING EMPIRICAL MODE DECOMPOSITION METHOD

2023-12-09T11:12:15+07:00

When the electrical power system appears agitated, it will lead to changes in dynamic characteristics such as power oscillation, voltage oscillation, frequency oscillation, especially low-frequency power oscillation on interconnections lines. These oscillations have the potential to destabilize the electrical power system. Accurate determination of low frequency oscillations for real systems is quite difcult. This paper introduces the initial research results on the determination of low-frequency power oscillation of the inter-regional power system based on the analysis method in the frequency domain and simulation in the time domain. Use the Hilbert Huang transform to examine the nature of the oscillations. The study also proposes the use of power system stabilizers to enhance the damping of oscillation and improve the stability of the electrical power system.

POWER ALLOCATION FOR ELECTRIC VEHICLE USE AUTOMATIC CHARGING CURRENT GEGULATION MODULE

2023-12-09T11:34:29+07:00

In recent years, the strong development of electric vehicles and hybrid electric vehicles, along with policies to encourage the use of electric vehicles, reduce emissions as well as reduce dependence on traditional energy sources. With that, electric vehicles can play an important role in sustainable development. However, the widespread use of electric vehicles will face challenges such as electric vehicles will add a signifcant energy load to the existing grid, battery degradation, charging strategies accordingly. In this paper, the author designs and manufactures a charging module that automatically adjusts the charging current for electric vehicles and proposes a method of power allocation for electric vehicles. Experimental results show that the use of a charging module that automatically adjusts the charging current ensures the safety of the existing power grid, and at the same time satisfes the demand of the vehicle owner.

DESIGN, MANUFACTURE, AND SURVEY OF ANALOG PID CONTROLLER

2023-12-09T11:49:45+07:00

Now, the strengthening of experimental equipment for training and research of the Department of Control and Automation - Division of Electrical and Electrical Engineering - Hung Yen University of
Technology and Education for the application training goal is very necessary. In order to meet the above goal, in this paper, the authors proposed the project “Design, manufacture, and survey of analog PID
controller for experiment” in order to built into modules: analog PID controller for experiment. Then, we perform the necessary experiments to evaluate the quality of them.

SYNTHESIS OF SILVER NANOPARTICLES BY GREEN CHEMICAL METHOD AND INVESTIGATE FOR ANTI-BACTERIA

2023-12-09T14:39:49+07:00

In this paper, spherical silver nanoparticles (Ag NPs) were synthesized by green chemical method from silver nitrate and fresh lemon extract. Optical properties, morphology and structure of the Ag NPs were analyzed by UV-Vis, SEM, EDX and XRD. As a result, the Ag NPs has a spherical shape with size about 40 nm. The antibacterial properties of Ag NPs dispersed in ethanol were realized by agar plate diﬀusion method. The result show that Ag NPs combined with ethanol have good ability to kill Coliforms bacteria. Ethanol without Ag NPs, a Coliforms resistance zone forms at 70% ethanol (volume concentration). When ethanol combined with Ag NPs, an antibacterial zone begins to form at concentration of 10 ppm Ag NPs in ethanol 40 %.

INTEGRATINON OF PERIPHERAL DEVICE ON THE CONTROL 5 DOF IGUS INDUSTRIAL ROBOT Abstract

2023-12-09T15:34:00+07:00

This paper presents an intergrated model of perepheal devicees, consisting the photoelectric sensor E3Z-T61 and relay, to extend the application of fve degrees of fredom Igus robot for a pick-place system. The locating positions of objects on a square transparent mica are designed along three rows with a distance of 70 mm and 80 mm. The pneumatic gripper mounted on the on the last link picks up objects at two positions in the 3rd row according to the sensor’signal, then place its at diﬀerent positions in the frst row or second row depending on whether the object is picked up in the frst or second position. The trajectories of the objects are programmed on a PC and Integrated handheld control system display and touch- Operating Panel using using movement commands, basic commands and advanced commands of the iRC programming software.

CONDITIONS FOR EXISTENCE OF SOLUTIONS FOR PARTIAL FUNCTIONAL DELAY DIFFERENTIAL EQUATIONS ON A HALF-LINE

2023-12-10T16:23:04+07:00

For the following class of partial functional delay diﬀerential equations

we establish the existence and bounded conditions of solutions. In the case of its linear part, the family operators (B(t))_t≥0, generates the evolution family (U(t,s))_t≥s≥0(on Banach space X) having an exponential dichotomy on the half-line and the nonlinear forcing delay term f satisfes the -Lipschitz condition, i.e., ‖g(t,u_t) - g(t,v_t)‖_C ≤ ‖u_t - v_t‖_C where u_t, v_t ∈ C := C([-r,0],X), and belongs to an admissible function space on the half-line. Our main method is based on the admissibility of function spaces and fixed point arguments.

RELATIONSHIP BETWEEN INTEGRAL MANIFOLDS FOR PARTIAL NEUTRAL FUNCTIONAL DIFFERENTIAL EQUATIONS

2023-12-10T21:15:36+07:00

In this paper, we describe the relationship between the solutions of the equation below with

under the conditions that the family of linear operators (B( ) t )t J ∈ defned on a Banach space X generates the evolution family (U t s ( , ))t s ≥ having an exponential dichotomy or trichotomy on the J, the diﬀerence operator F X :  → is bounded and linear, and the nonlinear delay operator Φ satisfes the ϕ -Lipschitz condition, i.e.,‖ ‖ ‖ ‖ Φ - Φ ≤ - ( , ) ( , ) t t φ ψ ϕ φ ψ   for φ ψ , ∈ , where ϕ belongs to an admissible function space defned on J, where J is a subinterval of the real line  . Our main method is based on Lyapunov-Perron’s
equations combined with the admissibility of function spaces and the technique of choosing F-induced trajectories.

RESEARCH DESIGNING A FASHION STYLE MODEL ON SCRATCH SOFTWARE

2024-02-16T13:58:26+07:00

Along with the explosive development of digital technology, technology handheld devices have become popular to help learners have active and effective interactions in the learning process. In this article, we refer to the content of researching and applying Scratch programming software to build dynamic models to simulate fashion styles. The research has designed data on Illustrator software to export PNG image files to Scratch software; a data system and build a dynamic model design process to help learners easily simulate fashion styles. The results show that the model works stably.

THE INFLUENCE OF SOFTENING FINISH TO SOME OF PHYSICAL AND MECHANICAL PROPERTIES OF KNITTED FABRIC I-COOL

2024-02-16T14:32:26+07:00

In the chemical treatment for the textiles material, the softening process is used very popular and important for most textile product types because, after softening process increases the aesthetic, comfortable and commercial values for the product. Today, the use of softener in textile fnishing has become popular and very common. However, using what kind of softeners, how much concentration and applied to what kind of materials, what makes changing properties related to the comforts of the product after softening process. This is the problem that many textile manufacturers has not yet given adequate attention. In the context of this study, we have selected weak cation Hydrophilic Silicon softener treatment for knitting I-Cool fabric with diﬀerent concentrations. Evaluating variation in the physico-mechanical properties of the fabric such as the drape, breathability, ventilation, wicking,... after fabric softening treatment, and then fnd out the optimum conditions based on poitn of view of creating the best comfort to the garments.

SIMULATION STUDY ON THE NO x REDUCTION PROCESS IN THE INTERNAL COMBUSTION ENGINE EXHAUST USING PLASMA REACTORS

2024-02-16T14:53:06+07:00

This paper presents the simulation results of the process of NO_x emission reduction using a dielectric barrier plasma reactor. This is also the premise for experimental studies and the application of plasma reactors to treat NO_x emissions in general and especially NO_xemissions from the emission components of internal combustion engines in particular. In this study, the author used the C++ programming language with input data including the gas flow rate entering the reactor, the amperage supplied to the reactor, the volume of the plasma in the reactor, and the pressure and volume of one mole of oxygen and nitrogen gas to simulate the NO x reduction process. Simulation results show that NO_x can be reduced by plasma, and when the concentration of oxygen in the exhaust gas increases from 0 to 5 %, the concentration of NO_x coming out of the reactor decreases sharply. However, when the oxygen concentration is greater than 5 %, the NO_x concentration coming out of the reactor does not change significantly. As the amperage of the plasma reactor increases, the NO_x reduction capacity also increases.

RESEARCH AND APPLICATION OF MATLAB - STATEFLOW SOFTWARE TO SIMULATE THE ELECTRONIC CONTROL OF THE LIGHTING SYSTEM IN CARS

2024-02-16T15:04:28+07:00

This paper presents the main results of studying the control process of the electronic ECU for some typical light systems in the automotive lighting system. Perform controller simulation with Matlab - Stateflow software, thereby clarifying the physical process occurring during the control of the ECU. Initial results show that, with some working modes of the system controlled by the ECU, the results are consistent with the actual operation of the lighting system in cars today.

SIMULATION OF STRESS AND DEFORMATION IN BUTT WELD JOINT FOR GMAW PROCESS

2024-02-16T15:18:22+07:00

This paper presents an application of Comsol software to simulate and predict the stress and deformation distribution on V groove- and bevel V groove butt joints under changing the bevel angle and welding condition in GMAW (Gas Metal Arc Welding). The size and value of applied heat source in GMAW process are calculated for twenty-four cases with different bevel angles for V- and bevel V groove joints and six other cases with varying the welding conditions. Results show that the residual stress and deformation of both types of butt joints increase with increasing chamfer angle and root opening. As welding using a bevel-V butt joint, the stress and deformation are smaller than that of a V-butt joint. Moreover, the stress and deformation increase with an increase in the welding current or a decrease in the welding speed. We can predict the stress and strain distribution in other types of welded joints using different welding processes based on the simulation results. From here, there will be a basis for selecting an appropriate welding condition and joint form to limit welding stress and deformation.

APPLYING LONG SHORT-TERM MEMORY (LSTM) DEEP LEARNING NETWORK TO DETECT OUT-OF-DISTRIBUTION IN VIETNAMESE

2024-02-16T15:35:58+07:00

When machine learning models are used in real-world classification problems, they tend to fail when the training and testing data different. Worse still, these classification models can fail to make highly confident predictions while being seriously inaccurate. For example, a medical diagnostic model can continuously classify with high confidence, even if it will label data that is difficult for human intervention, resulting in diagnoses that will be erroneous wrong. In this article, we will apply the Long Short-Term Memory (LSTM) deep learning network to detection data Out-of-Distribution (OOD) in Vietnamese. Then we will use the model evaluation index AUROC (Area Under the Receiver Operating Characteristics) and AUPR (Area Under Precision-Recall Curve) to evaluate the model.