Search

The regular shape of a circular dielectric resonating antenna (DRA) is changed in this paper. The proposed dielectric resonator has a perturbed circular shape in which the least arc to arc distance is same as that of the wavelength (λ) that is calculated from the design frequency. The proposed structure has a substrate and a dielectric resonator which include dielectric materials. In this paper different dielectric materials have been used both for substrate as well as dielectric resonator and the performance of the proposed DRA has been evaluated in terms of S-Parameter (

This paper presents the development of a three degrees-of-freedom (DOF) compliant parallel mechanism (CPM) with spatial motions, i.e., two rotations about the X and Y axes and one translation along the Z axis (θX-θY-Z). Such CPM is synthesized by the improved beam-based structural optimization method. The obtained results suggest that the proposed CPM is able to produce totally decoupled motions illustrated by a diagonal stiffness/compliance matrix, a large workspace of ±22,5 degrees × ±22,5 degrees × ±9,6 mm, fast dynamic response with the first natural frequency of ~100 Hz and high stiffness ratios between actuating and non-actuating directions (with stiffness ratios of 6210 and 2706 for translations and rotations respectively). Finite element analysis (FEA) is employed to evaluate the actual performance of the synthesized CPM with Ti6Al4V material in order to verify the correctness of the synthesis method. The effectiveness of the improved beam-based structural method is demonstrated by the good agreement between the simulation and predicted data with the highest deviations are 8.8% and 6.7% for the stiffness and dynamic properties respectively. In addition, some comparisons are carried out to investigate the advantages as well as disadvantages of the proposed CPM and existing designs. The comparison results show that the 3-DOF CPM presented in this paper has many merits compared to its counterparts. It can be used in various applications, e.g., the micro/nano positioners and alignment systems in precision engineering field due to its good mechanical properties (high stiffness ratios and fast dynamic behavior), large work range and fully-decoupled motion characteristic.

Over the last few years, existing and emerging Information and Communication Technologies (ICT) and artificial intelligence have been changing the way that factories conduct their manufacturing activities. Operation system of smart factories has been of great interest to researchers in recent years. However, the research concerning operations for the smart factory is still at the nascent stage. To address this need, we conduct a citation and co-citation analysis on smart factory operation system research published in the 11-year period from 2010-2020. A total of 351 papers were selected from Web of Science database. In the citation analysis, we depend on the degree centrality and betweenness centrality to identify 36 important papers. In addition, our main path analysis reveals the role of ICT in facilitating fast development of operation in smart factory. In the co-citation analysis, we identify four major research themes: resource reconfiguration, predictive production planning model, collaborative scheduling mechanism and technology basis of logistics. This is among the first studies to examine the knowledge structure of smart factory operations research by using evidence-based analysis methods. Recommendations for the future research directions have suggested based on our analysis.

This paper provides the modeling and control of stator active and reactive power for doubly fed induction generator (DFIG) under wind turbine systems using a direct power control (DPC) is applied to the grid side converter (GSC), also the rotor side converter (RSC) of the DFIG is controlling with the field control (FOC) to realize the decoupling control of the active and reactive power. For tuning the PI controllers is a tedious work and it is difficult to tune the PI gains optimally due to the nonlinearity and the high complexity of the system. This paper presents an approach to use the particle swarm optimization algorithm to design the optimal PI controllers for the rotor side converter (RSC) of the DFIG. Based on the simulation results, the PSO-PI provides lower value for the criteria and better response compared with the PI conventional.

Under the joint action of dynamic and static loads, the connecting bolts of the top cover of the pump turbine are prone to cumulative damage in local areas such as threads, resulting in cracks or development, and fatigue fracture may occur in severe cases, which will cause serious safety accidents. Therefore, it is necessary to carry out accurate fatigue life estimation analysis for connecting bolts, which has always been a hot spot and difficulty in the industry. This paper introduces several commonly used fatigue life analysis methods of parts, combined with the force characteristics and structural characteristics of the connecting bolts of the top cover, and analyzes and discusses the fatigue life analysis methods suitable for the top cover bolts. Finally, it is believed that the application of stress-strain field strength method can better describe the actual state of the bolt danger area, and the current damage state has an influence on the amount of damage generated by further loading, and the fatigue life analysis of connecting bolts can be combined with the stress-strain field strength method and variable damage linear cumulative damage theory, and the fatigue life and residual fatigue life can be estimated in the design stage or after the phased service of the bolt.

Incremental Sheet Forming (ISF) is emerging as one of the popular dieless forming processes for the small-sized batch production of sheet metal components. However, the parts formed by the ISF process suffer from poor surface finish, geometric inaccuracy, and non-uniform thinning, which leads to poor part characteristics. This paper deals with the influence of single point continuous local forming process parameters on the surface roughness of the product. Design of trials used for research planning and analysis and interpretation of results. The results indicate that the tool diameter (D), vertical step-down size (Δz), and sheet thickness (t) have significant effects on the produced profile accuracy, while the feed rate (f) is not significant. As a general rule, thin sheets with greater tool diameters yielded the best surface quality. The results also show that controlling all surface quality features is complex because of the contradicting effects of, and interactions between, a number of the process parameters.

Due to the shortcomings of waste bricks, they cannot be used repeatedly. The brick powder can partially replace cement for construction production, which can solve the problem of cement energy consumption. This paper studies the influence of brick powder on the performance of cement-based materials. The research shows that the water absorption effect of brick powder and the friction force are the two main factors affecting concrete. Energy dispersive spectrometer, inductively coupled plasma mass spectrometry and compressive strength tests show that the addition of brick powder leads to the increase of silicon/calcium. inductively coupled plasma mass spectrometry shows that although brick powder dissolves in the early stage, the volcanic ash effect is weak. The results of mercury intrusion porosimetry and ultrasonic pulse velocity are consistent with the compressive strength. When 5 % is added, it shows excellent durability. In addition, with the increase of age, the durability will not decrease significantly. Since the brick powder only needs to be ground to avoid the related process of cement, good economic and environmental benefits can be obtained with the increase of substitution rate.

Cellulose is one of the main components of plants, depending on the plants, the cellulose content can be up to 98%. Cellulose has a wide range of use. It can be used in the food industries, pharmacy, paper, and chemical industries. To extract the cellulose from biomass, the biomass needs to undergo a pre-treatment. This study uses steam explosion pre-treatment as it does not cause hazards to the environment, has low energy cost, and low investment cost. In this pre-treatment, steam will be injected into the biomass until the pressure reach 15 bar, then decline rapidly to make an explosion that causes damage to cellulose crystalline. After that, the process continues to main process, which are washing, and alcohol extraction. Then continued to alcohol recovery. After considering many factors, a cellulose plant from rice straw will be built in 2023 in industrial parks Java Integrated Industrial and Ports Estate or known as JIIPE with a capacity of 370,000 tons/ year. Based on economic analysis, this plant has an internal rate of return of 35.17% and a payout time of 3.98 years. This makes this plant feasible to be built.

This paper presents the simulation of beef freezing process by using ANSYS software. On the basis of simulation results, factors affecting the freezing time including air velocity and freezing temperature were determined. Within the air velocity range ω = (5÷15) m.s-1, an increase in the velocity by ω=1 m.s-1 led to a decrease in the freezing time by τ =(6,5÷2,0) %. When the freezing temperature was reduced by te = 1 K, the freezing time was reduced by τ = (3,2÷2,5) % in the freezing temperature range te = (–35÷–45) °C.

Currently, the research on the application of Single point incremental forming technology (SPIF) in Vietnam is limited. Therefore, the study of technology and equipment for the fabrication of SPIF machine and research on the ability of deformation of the formed material sheet is necessary and should be urgently carried out. The paper proposes a new approach to modularizing the structure of the Single point incremental forming machine by using standard parts, thereby improving the quality and reducing the cost of the machine and improving accuracy of the machine.

Stress concentration is a complex problem in material mechanics, especially in Aeronautics and Astronautics applications, the concentrated stress will do great harm to the safe operation of the launch vehicle. Therefore, it is a common practice to simulate and verify the structural design or manufacturing process in the use of materials and dynamics. This paper first introduces the problem of stress concentration in aerospace, demonstrates the necessity and importance of studying this problem, at the same time, puts forward a stress concentration solution based on finite element method, which simplifies the geometric model by using symmetrical characte-ristics, so as to reduce the batch data of analysis. Compared with the conventional analysis using Patran and NASTRAN, its geometric model has a higher degree of discretization, The superiority and reliability of this method are verified by two examples. The results show that this finite element method is more accurate and effective in dealing with stress concentration problems, especially complex geometric models, and has high value for engineering practice.

In this paper, the on-line quality control feature of the injection molding machine based on the statistical process of thermoplastics product has been developed. The optimal process begins with collecting data and setting up the parameter of the injection machine according to the design of experiment. Four control parameters are set up on Demag Ergotech 200-840 Dragon. A series of tests using a body-outdoor led lamp has been conducted by means of both approaches simulation-based and experimental-based by which is injected using two-cavity injection mold. In simulation mode, clamping force and total weight were assigned as final responses, while total weight only is used as a response in experiment mode. The molded-parts were validated using thirty samples that are divided into a three-batch production process. The application of the on-line statistical quality check feature in the injection molding machine can be used as a quality control method by setting up barrel temperature, screw-back position, injection speed, and injection pressure.

Direct-drive electric motor or In-Wheel Hub Motor (WHM) is gradually becoming popular as a new solution for electric propulsion. By meas of direct drive, the conventional transmission of belt or chain sprocket is not required to deliver the high torque requirement at the wheel. This paper studied metamodel machine leasning (MOP-ANN) implementation to predict the relationship model of geometries input of 42 slot/40 pole WHM with corresponding output performance. The multi-layer perceptron (MLP) of the neural network structure was trained to reveal the underlying pattern within the data sample. The sample data was obtained from a sensitivity analysis drive from FEA. The optimum geometry of the motor was directly solved by implementing a multiobjective optimization (MOO) method of genetic algorithm. Finnaly, the optimum geometry of the MOP-ANN based result is validated by FEA.

Nowadays Wireless Sensor Networks (WSNs) are a very promising device to monitor environmental events, which are used in many application areas such as agriculture, environmental monitoring, air-water pollution, greenhouse, health monitoring, structural monitoring etc. Also, WSN needs effective and efficient way of collecting data from the area over which it is deployed, since the network consists of battery-operated nodes with limited energy. Improving the lifetime of WSN for continuous monitoring applications are very essential because of simple deployment, low installation cost, lack of cabling, and high mobility. The better energy conservation and reliable data transmission would be achieved in WSN by adopting efficient routing protocols for better and reliable communication. Also, security in data transmission in WSN is still a challenging task. Hence, a better way of encryption has to be computed to promote a reliable transmission between the nodes. In this paper discusses about different routing protocols which support energy efficiency and security techniques in WSN.

This paper introduces the rapid automatic control module of trawler based on the hydraulic system of ‘Zhejiang fishery scientific research ship No.2’.The hydraulic simulation model of double motor winch system is built in AMESim software, and SIMULINK module in MATLAB software designed closed loop fuzzy PID controller for hydraulic system simulation. through fuzzy PID control technology drives the hydraulic winch to quickly adjust the tension of the traction, maintain the stable balance of the traction force, maintain the optimization of network horizontal expansion, not only improve the fishing efficiency, but also timely and effective protection mesh. the technical achievements formed by the research will enable small and medium-sized trawlers to adjust the tension under various working conditions through the fuzzy PID control system to stabilize the opening shape of the trawl, so as to improve the automation level and fishing efficiency of related trawling equipment, and provide technical support for precision fishing.

In this paper, by analyzing the structure and material characteristics of skid landing gear, the skid landing gear model is established by using CATIA software. In the explicit dynamic analysis type of ANSYS software, the force comparison between the impact surface of soil material and the impact surface of rigid material is made, combined with the change of momentum and energy in the process of touching the ground. This explains the necessity of landing drones on soft landing surfaces such as soil. In addition, LS-DYNA was used to simulate the dynamics of landing gear, and the strength of landing gear was analyzed according to failure criterion.

This paper provides a complete overview of the entire process of designing a welding head moving device and its implementation as a semi-automatic welding machine. The mechanical structure of the device is designed based on the size of the material pipe and the accompanying technical requirements. The system is equipped with an arc generator set and a rotary speed control unit allowing its use as an orbital welder.

The Smart Foundry concept promises benefits of improved foundry supply chain quality, more sustainable metal processing, and improved customer support. A significant need includes automated data gathering and visualization of the data. In metal foundries regardless of manufacturing small parts in mass production or big parts in small production, metal castings are difficult to trace individually. Furthermore, to identify causes of defects through statistical correlation of recorded process inputs to inspected part defects becomes challenging. In this paper we present a sand-casting Smart Foundry operation including automated scan-based tracking of cast parts through the foundry and supply chain. This allowed process data collected to be automatically associated with the part being processed. This study proved that additively manufactured tags can be utilized in foundry serial production operations for direct-part-marking of castings and both digital tracking and process data collection of individual cast parts. Further we made use of the captured part-by-part data to develop a root cause analysis for quality defect causal correlation. The results indicated that the casting feature dimensional quality was highly correlated with variations in sand bending strength, tin content in aluminum, and pouring time, among others. Such insights are available when tracking process and part data as part of a Smart Foundry.

Brakes have huge importance on a bike with regards to safety. Proper structural sturdiness and superior heat dissipating capabilities provide better performance while braking and longevity to the system. Transient thermal and structural analysis of four Indian two-wheeler disc brakes is completed by using ANSYS 2021 R2 student version software. The comparison results provide comprehensive insight into the thermal and structural characteristics of all four-disc rotors used in the industry. A comparative conclusion with respect to performance of each disc rotor in the respective components of the analysis like, temperature, heat-flux, total deformation and equivalent stress analysis is presented in this paper.

As the energy crisis's impact spreads, energy consumption has emerged as the fundamental impediment to industry's long-term viability. Utilizing and recovering various sources of waste heat can considerably reduce an organization's energy use. Energy conservation is crucial not just for fuel use, but also for the conservation and protection of the global ecosystem. As a result, it is necessary to make a concerted effort to save energy generated by waste heat. This paper aims to develop flue gas as a substitute for wood burning for drying mold at foundry shop of G-7 trading and industrial PLC. Flue gas temperature and velocity were measured at various locations throughout this study, and an analytical computation was done on the flue gas supply system and mold drying chamber. To show what happens within the hot flue gas supply duct and mould drying chamber, Computational Fluid Dynamics (CFD) Ansys software was used. The business benefits by eliminating the usage of wood as a fuel and making the process more cost-effective and environmentally friendly by capturing hot flue gas from the top section of the furnace or chimney and supplying it through duct to the drying chamber to dry the mold. As a result, the negative impact of deforestation will be mitigated, and a favorable working environment will be established.

Alternative synthesis methods are need of the hour to provide easy protocol for synthesizing biologically active heterocyclic compounds. In this connection, this paper describes the development of a concise, convergent protocol for diversely substituted Suzuki–Miyaura cross-coupling reactions of heteroaryl bromides and boronic acids under microwave irradiation using Sodium aluminate (NaAlO2) as a solid support as well as base. According to my knowledge, this is the first report of the strategy that involves the use of zinc as a catalyst on fused tricyclic di-halo quinolones in a solvent-free condition using simple microwave irradiation. Earlier research from the same laboratory established a solid support assisted Suzuki–Miyaura cross-coupling reaction for forming C–C bonds under the influence of microwave irradiation. Therefore, sodium aluminate (NaAlO2) was attempted as a base and solid support instead of traditional mineral bases. Moreover, zinc was used as a catalyst replacing palladium. The new method is unique and effective due to its energy economy, procedural simplicity, and general applicability. Moreover, the use of Sodium aluminate (NaAlO2) is expected to extend this green-protocol and atom-friendly chemistry for the synthesis of varied heterocyclic compounds of interest.

In this paper, through the construction simulation of the installation and jacking of a large steel grid project, ANSYS software is used to select the corresponding finite element module, and by analyzing the construction models of different modes and different load conditions, the analysis results and structural models are displayed. The 12 supporting hydraulic jacks can meet the overall steel structure hoisting requirements on site. At the same time, the calculation model takes into account the deformation of the overall grid during the unloading process. After testing, the maximum displacement is 7mm, which meets the requirements of national regulations. This method better supports the construction guidance, and also achieved good benefits during the on-site implementation process. The installation plan and jacking technology are worthy of reference.

In this paper, a higher order shear deformation theory is used to analyse the thermo-mechanical bending response of perfect-imperfect rectangular plates for hybrid ceramic and metal type (FGP) functionally graded plates with porosities. Based on the mixing law, the FG porous material qualities fluctuate with the thickness of the FGP layer. The equilibrium equations are found using the total potential energy approach. For simply supported (FGP) porous plates, the thermo-mechanical response is calculated. Analytical research shows the correctness of the existing high-order shear deformation theory in predicting the thermo-mechanical response of perfect-imperfect rectangular FG plates. Geometric characteristics, thickness ratios, gradient indices, porosity coefficients, mechanical loading, and thermal loading are all covered. According to the findings, the proposed hypothesis is more likely to be correct when it comes to the thermo-mechanical response of FG porous plates.

Compared to CNC machines, robotic milling has performance limitations such as accuracy and quality. The main source of the robot’s inaccuracy during machining is the flexibility of its parts (body or joints). This error disturbs the movement of the end effector, affecting the part’s surface finish. In order to improve the robot’s accuracy and minimize the positioning error of the end effector during the milling operation, this paper presents, first, a method based on the elasto-static model to predict the Cartesian deflection of the end effector of a three DOF redundant planar robot, and second, optimization techniques with original objective functions based on the single and multi-objective genetic algorithm, which will be presented and compared. The programming of the two methods and the results of the study will be done using MATLAB software. The analysis of simulation results of the two optimization techniques GA and MOGA revealed that the tool configuration and cutting parameters used for robotic milling have a direct influence on the robot's path accuracy and milling performance. Whereas for a φ0=69.6, φf=72.43 the maximum tool deviation in its path is Δxmax ≈ |0.125| mm with a maximum roughness profile height Ra = 1600 μm. While the positioning error is said to be minimal Δxmin ≈ |0.025| when φ0= -38.67, φf = -35.92, and the roughness Ra= 25 μm.

This paper presents the peridynamic (PD) numerical model for simulating a tensile test until total fracture for a brittle polymeric material namely polymethyl methacrylate (PMMA). U-notched and V-notched specimens were used to investigate the effect of the notches on the elongation and fracture of PMMA. The tensile elongation of PMMA exhibits nonlinearity with respect to the applied load, while the fracture occurs when the material stress has reached the ultimate tensile stress of the material. Similar elongation and fracture properties were applied on PD simulations. Two types of elongation equation are used namely brittle and ductile equations to form PD-brittle and PD-ductile models. The published experimental data of tensile fracture test on notched PMMA specimens are used as reference to validate the simulations of the PD models. The PD numerical force-extension curves have good quantitative similarity for V-notched specimen but adequate quantitative similarity for U-notched specimen. As for the quality of the fractured specimen shape, the PD simulations have good similarity for the V-notched specimen but adequate similarity for the U-notched specimen. The plot of the internal force distribution from the simulations of PD shows good qualitative similarity to the plot of the stress distribution from the published data of FEM in terms of stress concentration. From the PD results, it is observed that the PD-ductile model has better capability in producing accurate simulation of the notched specimens than the PD-brittle model.

A total of seven beam specimens were carried out to investigate the shear behavior of reinforced concrete (RC) beams strengthened by carbon fiber reinforced polymer (CFRP) grid with epoxy mortar, considering various shear span ratios, concrete strengths and intervals of CFRP grid. According to the test results, the nonlinear regression analysis was conducted and further a prediction method of shear capacity was proposed for CFRP grid-strengthened RC beams. The results showed that the shear behavior of strengthened beams were obviously improved, mainly due to CFRP grid. The shear strengthening effects of CFRP grid not only had a relation to the intervals of grids, but also were closely related to the shear span ratios and the concrete strengths, and thus both of them also cannot be ignored in design. The novel prediction method proposed in this paper, was verified by collecting data and regarded as a good predictor.

Pollution by textile dyes on waterbodies is an issue for both human health and the environment. To remove/degrade dyes, many approaches (coagulation, membrane separation, and adsorption) have been investigated. However, the use of semiconductor-assisted materials in conjunction with sustainable solar energy has emerged as a possible solution to the problem. Although single component photocatalysts have been tested, composites of semiconductor materials are being employed owing to their low efficiency and stability due to the high recombination rate electron-hole pair and inefficient visible light absorption. By combining two or more semiconductor components, semiconductor heterojunction systems are created. Overall stability is increased by the synergistic impact of their features, such as adsorption and better charge carrier movement. This paper discusses current advances in advanced nanocomposite materials utilized as photocatalysts, as well as the utilization of heterojunctions, crystallinity, and doping to improve photocatalytic characteristics. The conclusion includes a summary, research gaps, and a forecast for the future. This study will aid in the development of efficient heterostructure photodegradation systems by providing a comprehensive appraisal of recent advances in demonstrating effective nanocomposites for photodegradation of Rhodamine B dye under ideal circumstances.

During the last two decades, over more than five million research papers (articles, reviews, communications etc.) were published on nanocomposite materials. Most of them are excellent contributions that already mingle the readers’ and researchers’ interests; thus gaining many citations. This mini-review is focused on advancement in next-generation nanocomposite materials based on optical and sensing applications; and their practical execution. Some recent novel developments will be highlighted and future trends will be discussed. Nowadays, nanocomposite has ended up one of the most popular materials with potential usage in various scope, including packaging, automotive and aerospace industry, batteries with higher power output, flexible batteries, making lightweight sensors, in photocatalysis and making tumours easier to look at and to eliminate. New materials, viz. designed polymers, metal oxides, alloys, chalcogenides, nanostructured and hierarchical carbons, regularly induced researchers and engineers; to test and compare them with existing sensors of multifarious sorts. Nanocomposites not only offers’ the new technology and business opportunities in all sectors of the industry but also it tender innovations and new openings for all divisions.

Multi-pass solar air heater is attributed to the increase in efficiency due to reduce top heat loss. In this paper, a quadruple-pass solar air heater equipped with longitudinal fins on both sides of an absorber plate was investigated for efficiencies and axial temperature distribution. A mathematical model is formulated in form of ordinary differential equation (ODE) from eight heat transfer equations to solve for four local temperatures of airflow and four local temperatures of surfaces (two glass covers and two absorber plates). ODEs are solved by numerical integration and validated by the comparison with the published data. The current approach is conducted since an analytical model and parametric study on quadruple-pass solar air heater has not been found in the open literature. Among the fin parameters including thickness, quantity, and height, the fin height has a great influence on thermal efficiency. Thermal efficiency can reach 65.7% at maximum fin height. Reynolds number of 5500 achieves maximum effective efficiency of 63.5%. When the Reynolds number is large, heat transfer in the fourth pass is poor due to the sharp drop in surface temperature at high airflow rate.

Capacity planning is the process of determining the production capacity needed by an organization to meet changing demands for its products. Production capacity planning is generally based on all capabilities determining that wireless production is stable, with no fluctuations in machine downtime, variable processing times, defective products, etc., and use the mean for cycle time. However, actual production not only has many fluctuations in human resources that affecting the production time on each stage, but also affected by defective products leading to inaccurate planning. Therefore, planning production capacity under uncertain conditions is essential for any manufacturing enterprise. This paper proposes a model of capacity planning in uncertain conditions using real-time observation and then distributing observation time from which to analyze production capacity. Uncertainty factor as labor and defective products will be considered in this model.

This paper presents the research on the process of designing and optimizing the powertrain of electric vehicles, such as the general arrangement of electric vehicles, the design of electric motors, transmission systems, battery systems, as well as selecting the appropriate layout design. In addition, the article analyzes the computational models of electric drive systems, energy systems and calculates the performance of these systems in accordance with actual use. Finally, design and simulation calculations of the powertrain and energy of electric vehicles are performed using Simcenter Amesim software. Keywords: Electric vehicle, battery, electric motor, Simcenter Amesim

Currently, the fumes and dust generated from metal cutting and welding are not often treated well in many factories. This paper presents the results of designing, manufacturing the welding fumes filter system by applying electrostatic precipitator methods as well as studying the factors affecting performance of filters. There are many factors that affect the efficiency of electrostatic precipitator filtration, in this study, the welding fumes filter was experimented with parameters of gas flow velocity, filter pipe diameter and power capacity to find out the appropriate parameters. The outlet air quality was measured with a dust concentration gauge and the Box-Behnken method was used to determine the relationship among experimental parameters. The filter parameters are optimized to achieve 99% of filtration efficiency. The research results will be applied in practice to ensure the health of users and improve the surrounding environment as well.

In the field of food cooling and freezing computation, the accurate determination of thermo-physical properties such as specific heat, thermal conductivity and density is necessary and specially important to optimize the energy consumption of equipment. These parameters depend on the food composition and temperature usually determined by theoretical or experimental method or the combination of both. Experimental method using differential scanning calorimetry (DSC) is the best approach to yield correct results. However, DSC method requires expensive equipment and it might be not suitable for limited funding in some Vietnamese research centers. Therefore, the line heat source was chosen in this study.This paper introduces a new approach to determine thermal properties of the Vietnamese Pangasius in the temperature range from-40 °C to +40 °C using the line heat source. The results indicated that there is good correllation between the obtained measured data and the results calculated using theoretical models as well as other published experimental results.

Currently, the difficulty of delivering packages, goods in transportation is a very concerning issue in both urban and suburban areas when traffic congestion is increasing significantly. Therefore, the purpose of this study is to design an unmanned aerial vehicle using quadrotor to transport goods such as food, home appliances or drugs, and blood to customers. This paper presents the sizing algorithm applying blade element momentum theory to determine necessary specifications for the electric propulsion system of multicopters. These results are then used to design the appropriate configuration that can handle the mission profile. Finally, analyzing and evaluating structural strength and failure of the designed delivery drone by applying the Tsai-Wu criterion.

The nonlinear steady state and dynamic response analysis of focused ultrasound smart biomaterials is presented in this paper. The increasing demand in scientific research to develop robust governing nonlinear model with adequate boundary conditions for proper understanding of the dynamics of smart biomaterials by applying focused ultrasound excitations is of great concern particularly in remote biomedical applications. Hence, in this study, a model which describes the nonlinear steady state and dynamic response of the materials for focused ultrasound actuator which is a nonlinear partial differential equation has been developed. The Galerkin Decomposition and the Differential Transform Methods are applied to obtain the solution of the governing equations. The solutions were validated with the numerical Runge-Kutta method of fourth order and verified with results obtained in recent studies and good agreement is established among them. The effects attenuating coefficient, modal number, and damping term on the steady state response of the smart biomaterials are investigated. From the results, it is observed that the steady state deflection of the system as indicated by the attenuating coefficient is lowest for clamped-clamped boundary condition and highest for clamped-free or cantilever condition. In addition, an increase in modal number and magnitude of the damping term results in an increase in the number of nodes and anti-nodes and a decrease in the amplitude of vibration over time respectively. Hence, this study establishes the practical applications of attenuating coefficient and boundary conditions as controlling factors in the design of smart biomaterials.

The bottom hole opening method is generally used to rescue the people trapped inside the capsized vessels. In this paper, a new sealed cabin with flexible cabin shell and rigid pedestal was proposed to rescue people in distress through the inner hole cut on the bottom hull. The parameters of the cabin pedestal and the sealed pedestal are optimized respectively to reduce the weight of the whole cabin. According to response surface methodology to analysis the relationship between the tress and the structural parameters. The maximum equivalent stress and maximum deformation are the constraint conditions and the total mass of the structure is the objective function, and the multi-island genetic algorithm is used to optimize the model, and the approximate optimal solution was finally obtained. The results show that the strength of cabin pedestal and sealing pedestal meet the application requirements.

In this paper, the seismic behavior of the main nave and cloister of the Guadalupe Church and San Diego Convent is studied, a structure dating from the 18th century and built in the historic center of the city of Morelia, Mexico, considering a set of 9 real seismic acceleration records of September 19 2017 earthquake obtained at seismic stations located near the epicenter but at almost 100 kilometers from this building, which were used first without any scale factor and then a scale factor was applied to reach the expected maximum peak accelerations of the ground at the site for probabilistic return periods of 475 years and 975 years.

Offline programming is a critical step in the implementation of various robotic tasks such as pick-and-place, welding, cutting, and milling. This paper describes a simulation study that analyses the accuracy of the robot's path tracking, during tasks that require the robot tool to interact with the environment, while considering the current operating conditions. To accurately determine the actual position of the Tool Center Point (TCP) and the associated orientation of the end effector, the study will first establish a robot model that takes into account the elasto-static behavior during the milling process that generates significant contact forces on the end effector. Then, an offline simulation tool is developed within the SolidWorks® CAD environment. The analysis of simulation results from multiple scenarios revealed that the tool/material contact forces were the main source of the robot's deviation from its nominal trajectories. Moreover, the range of positioning errors varies according to the architecture of the robot and the workpiece emplacement. Depending on the working conditions, the tool deflection ranges from 0.1 mm to 0.75 mm in the or cutting directions and increases as one moves away from the reference frame, while the Cartesian orientation deviation is negligible (less than 1°).

To our knowledge, very few models have described the thermal behavior of granular media or powders as a function of the mechanical stresses to which they are subjected. In recent years, many researchers have expressed great interest in establishing laws that can show the relationship between the apparent thermal conductivity and the mechanical behavior of granular media. This paper presents an experimental study of heat transfer enhancement using granular blocks. A number of experiments were carried out in the test section of a wind tunnel where velocity and temperature measurements were performed. The velocity profiles permitted us to have an idea on the flow structure in the presence of granular blocks. The temperature measurements under various operating conditions (various Reynolds numbers and granular blocks structures) led us to the conclusion that using granular blocks can improve the thermal transfer in comparison with the case of a smooth channel and this enhancement is strongly dependent on the geometrical and thermo-physical properties of these blocks.

The increasing penetration of RES and the intermittent nature of various distributed power generation (DG) resources have created uncertainty in variable power production and power systems. The overall energy output of a wind farm may be optimized by strategically positioning wind turbines. This paper proposes a three-step strategy to dealing with the difficult-to-control problem of wind farm layout optimization. To construct the non-wake and wake impacts at various levels, three case scenarios are studied. The proposed strategy is used to a particular Ant-Lion Optimization Algorithm (ALOA) as a novel approach to producing highly efficient optimal output power, as well as case studies using actual wind data assessing potential turbine site. Finally, the simulation results demonstrate that the suggested approach is robust in ALOA design because it further reduces the objective function on the best new outcomes to implement all network restrictions acquired via the analysis.

In this paper, we present a modeling of the photovoltaic array in order to tracking the maximum power point (MPPT) using a soft computing approach based on artificial neural network, The maximum power point tracking MPPT play a crucial role in photovoltaic systems for their ability to maximize the power output under varying conditions; The photovoltaic array modeled and implemented in matlab simulink environnement using the conventional perturb and observe algorithm for multiple ranges under varying temperatures and irradiances levels, a feed forward neural network collect the training data from the photovoltaic array simulink model, after the training process check, the neural network model tested with new temperatures and irradiance data to predict the maximum power point of the photovoltaic array, The developed neural network model shown an interesting results compared to simulink model based on classic perturb and observe algorithm.

Various researchers have developed a model of conventional H2O -LiBr absorption machines, with the aim of predicting their performance. In this paper, the methodology of the adaptation of the characteristic equations is applied; this model is able to represent the cooling capacity of the double effect absorption chiller by means of simple algebraic linear equation. As a result, it is concluded that a good agreement between the theoretical simulation using the thermodynamic model and the results obtained on the literature. The results achieved through the adapted characteristic equations model have a deviation less than 10% for the cooling capacity and the coefficient of performance COP, and less than 15% for the heat capacity comparing to the thermodynamic model results. The developed characteristic equations and their assessment are useful for the simulation and the control purpose.

The author of this scientific paper studies the stress-strain state of the solar panel of a small spacecraft after a temperature shock. The temperature shock is caused by the entry or exit of a small spacecraft into or out the Earth's shadow. In this work is considered a one-dimensional model of thermal conductivity. It is assumed that the solar radiation flux falls properly on the solar panel. Violation of normality due to deformations is neglected. A special feature of this work is to take into account the actual fixing of the solar panel. The boundary conditions in the form of a seal are preserved. However, the mobility of the smallest spacecraft is taken into account as a result of the occurrence of a longitudinal force in the solar panel during a temperature shock. The results are compared with the simulation data without taking into account the mobility of the small spacecraft. The results of this work can be used in the design of small spacecraft for technological purposes to meet the requirements for microaccelerations.

The output power of Direct Methanol Fuel Cells (DMFC) is one of the most important elements which limit the performance of DMFC. In order to enhance performance of DMFC, it is necessary to have model to modeling the output power of DMFC. In this paper, a novel model base on Support Vector Regression (SVR) to modeling the output power of DMFC base on output current (I) and operating temperature (T). The test result is shown that the generalization ability of SVR model is high accuracy. This investigation suggests that SVR is quite satisfied used to developing a DMFC model and can be used for controlling, optimal designing and feasibility study of the DMFC system.

The water temperature distribution and spatio-temporal variation law of the reservoir have a great influence on the water quality and ecological environment of the reservoir, and it is also an important temperature boundary condition for the design of concrete dam of hydropower station project, which is of great significance for the optimal design and operation of the reservoir. There are many factors affecting the water temperature of the reservoir, and it is difficult to predict the water temperature distribution accurately because of the lack of data and experience. In this paper, a numerical analysis model is established for the reservoir of a hydropower station on the Nam Ngum in Laos, and the water temperature of the reservoir is calculated and predicted, and the water temperature distribution in the reservoir and the water temperature distribution in front of the dam are analyzed and discussed. The results show that the solar shortwave radiation is the main factor affecting the temperature stratification of the reservoir. The stable low temperature layer of the reservoir is not obvious, but there is a tendency to form stratification. The research results can provide water temperature value for the design of concrete dam of the hydropower station and provide reference for the prediction of the water temperature of other similar reservoirs.

In order to study the influence of the splitter plate in the elastic support system, the SST k-omega turbulence model is used to solve the problem, and the cylindrical system with splitter plate is numerically simulated by overset mesh. This paper studies the effect of the splitter plate on the vibration system at different deflection angles. The results show that the splitter plate has little effect on the system when the deflection angle is low. When the deflection angle is about 10 degrees, the system vibration characteristics will have a sudden change, the amplitude will decrease, and the vortex frequency will increase. Between the deflection angle of 10 degrees and 45 degrees, as the deflection angle increases, the amplitude increases and the vortex frequency decreases. It can be seen from the motion trajectory that the deflection angle changes suddenly after 10 degrees, and the system has a very small amplitude between 10 degrees and 25 degrees. In this declination interval, the splitter plate controls the vibration of the cylindrical system better.