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Research on Forming Quality of GH4169 Superalloy Multi-Step Hollow Turbine Shaft by Three-roll Skew Rolling
Full text linkAbstract: This paper innovatively proposes a three-roll skew rolling process for flexible forming of hollow turbine shaft, which solves the problems of long manufacturing process and low material utilization of hollow turbine shaft, the core component of aeroengine. Simufact.Forming 14.0 (SF) numerical simulation software was used to establish the finite element model of two-pass three-roll skew rolling of the GH4169 superalloy turbine shaft. The effects of process parameters on the outer diameter error, roundness error and wall thickness uniformity of the rolled piece were investigated by single factor experiments. A five-factor three-level orthogonal test was designed to explore the optimum process parameters by \u27 comprehensive scoring method\u27. The results show that the optimal process parameters are that the first pass roll rotating speed is 40 rad/min, the first pass axial speed is 15 mm/s, the second pass roll rotating speed is 50 rad/min, the second pass axial speed is 25 mm/s, and the billet preheating temperature is 1000ºC. The axial velocity of the second pass has the greatest influence on the test results, while the rotational speed of the second pass has the least influence. Under the optimal parameter combination simulation experiment, the outer diameter error, outer roundness error and wall thickness standard deviation are 0.151 mm, 0.121 mm and 0.034 mm, respectively, which are better than the results in the orthogonal test table. The research results provide a theoretical basis for realizing flexible, economical and high-quality forming of hollow turbine shaft by three-roll skew rolling
Modeling and Optimizing Automotive Waste Recovery for Optimal Performance
Full text linkAbstract: It is vital to explore an effective way to capture waste heat from modern automobiles. This research outlines the current methods to harness that excess heat from the exhaust system and a proposal to use a high-efficiency printed-circuit heat exchanger (PCHE) to harness the heat. The research also revealed a unique iteration process that encompasses testing of the exchanger in a closed-loop steam system which would serve as the basis for future experiments. In lieu of experiments, data was collected from peer-reviewed research of other scientists to approximate the effectiveness and efficiency of the system. The following facts were theoretically revealed by the derived model. The theorized heat exchanger was found to have a maximum transfer rate of 510 kW while the maximum heat supplied by the exhaust is around 100 kW. The exchanger is sufficiently designed to capture energy wasted by the engine through the tail pipe. With a mass of 5.169 kg for the exchanger alone and the estimated amount of fluid, turbine, generator, and piping to be no more than 50 kg, the vehicle will experience very little mass increase
MIG-Assisted Kernel-Enabled Robot (MAKER) Arm for Seamless Automobile Maintenance and Service
Full text linkAbstract: There is a definitive increase of excellence in the field of robotic automation, with automated vehicles that can drive people anywhere to automated robots that can perform high-risk surgeries remotely. Robotic automation was initiated as an industrial-grade asset capable of performing complex tasks and replacing humans limited by fatigue. With the advent and rise of Industry Revolution 4.0 (IR 4.0), in the modern world, one of the major markets that IR 4.0 occupies is the automobile industry. The automobile industry heavily employs robotic technology for vehicle manufacturing and assembly, yet post-sale servicing and maintenance remain predominantly manual. This discrepancy results in a gap in the efficient and timely maintenance of vehicles once they’re in the hands of customers. According to a report of Allied Market Research [1], the expected Compound Annual Growth Rate (CAGR) of the global automobile repair and service market from 2022 - 2031 is expected at 7.6%, corresponding to 1,656.21 billion US dollars by 2031. This establishes the scale of the market that the proposed solution is going to be primarily based on. This paper proposes a MIG-based solution for providing welding service to damaged and sheared automobiles, thus reducing the stated discrepancy. The proposed solution creates a kernel environment where the twin-headed robotic arm can assess its surroundings and perform appropriate action from its operation pool using Reinforcement Learning and Machine Learning. The twin-headed robotic arm holds a torch and lead (Al) on the heads to perform the desired operations. This innovative approach is equipped with advanced sensors and programming to accurately detect, diagnose, and service vehicles by leveraging On Board Diagnostic (OBD) systems. This study delves into the theoretical and technical complexities of building an automated welder that explores the practical application of robotic technology in the automobile aftermarket. Notably, this technology promises improved accuracy, consistency, and timeliness in car maintenance, significantly reducing human error, improving service times, increasing productivity, and inducing economic growth
Linear Active Disturbance Rejection Lateral Controller for Unmanned All-Terrain Vehicle
Full text linkAbstract: To address the disturbance of model uncertainty, a linear active disturbance rejection controller (LADRC) was designed for robust lateral control of unmanned all-terrain vehicle. In terms of relative motion of target node and current state, first-order lateral tracking model is established. According to the developed model, linear tracking differentiator (LTD), linear extended state observer (LESO) and linear state error feedback (LSEF) are designed in turn. LESO could observe the uncertainty of system and LSEF could compensate the uncertainty to make system robust. In order to verify the effectiveness, two typical scenarios, circle and double lane tracking, were designed for test. And the uncertainties of wheelbase and steering ratio were considered. Results illustrate that the designed LADRC can stably control the unmanned all-terrain vehicle tracking reference trajectory under both scenarios and has the advantages of small tracking error and small overshoot compared with the conventional pure tracking methods
Sustainable Energy Solutions for Himachal Pradesh: A Comparative Study of Solar Panel Technologies
Full text linkThe pursuit of sustainable energy solutions is critical in regions like Himachal Pradesh, India, where environmental preservation and energy access must go hand in hand. This study presents a comprehensive comparative analysis of two solar panel technologies—fixed tilted and two-axis rotating rooftop systems—under the state\u27s on-grid rooftop solar scheme supported by central and state subsidies. Using detailed simulations in PVsyst, the research evaluates the systems’ energy efficiency, economic feasibility, environmental implications, and policy alignment. Results show that while two-axis rotating panels offer moderately higher energy yield (6.23 kWh/day vs. 4.78 kWh/day), fixed tilted panels are economically more viable, exhibiting a shorter payback period (1.8 years vs. 2.3 years) and lower installation and maintenance costs. These findings endorse fixed tilted panels as a more cost-effective and sustainable solution for residential solar adoption in the region
Investigating How Robotics Activities Shape Elementary Students’ Attitudes Toward Music Composition and Coding
Full text linkThis mixed methods sequential explanatory study explored how computational thinking influences elementary students\u27 attitudes by engaging the students in coding a music composition with an autonomous robot. Pre and post tests were used to document students’ attitudes toward music composition and coding over the course of six weeks. Eighty fifth-grade students participated in the music composition project, coding for one hour each week in an engineering class. The students were randomly organized into four study groups: individualized, collaborative, traditional, and Use-Modify-Create (UMC). Findings indicate that students experienced a significant increase in positive attitudes toward music composition after the robotics coding activity. Both the individualized and collaborative groups reported enhanced enthusiasm for music composition, while the UMC group showed increased positivity towards coding and greater confidence in their coding abilities. These results suggest that music educators can enhance student attitudes toward both computational thinking and music composition by integrating robotics into the music curriculum. The main contributions of this study include: (1) empirical evidence of positive attitude changes toward music and coding through robotics; (2) comparative analysis of four instructional modes; and (3) a practical framework for integrating robotics into elementary music education
Accelerated Polymer Photodegradation
Full text linkAbstract: This article presents preliminary results of the accelerated degradation of polymers using concentrated solar radiation. For this purpose, a passive solar concentration prototype was designed, which consists of four trapezoidal mirrors placed in the shape of an inverted truncated square pyramid. The mirrors are placed at an angle of 30° respect to the zenith. The prototype has a square base of 46 cm x 46 cm where the polymers to be irradiated are placed and a geometric concentration ratio, CRg, of 1.89. The mass change was determined after 30 days of exposure to solar radiation, and the temperature variation of some samples as a function of irradiance was obtained. In addition, a computer simulation was carried out using the free access software Energy2D. Some polymers maintained their flexible mechanical properties, such as PET (type 1), others were partially embrittled, while type 2, 5 and 7 polymers were completely embrittled. It was possible to reduce the degradation time of different types of commercial polymers, while polymers exposed to non-concentrated radiation and without exposure remains intact. Embrittled polymers can be used as waterproof material in slabs and pre-cast walls, as well in applications where they are not exposed to solar radiation. On the other hand, the polymers that remained intact must be used in applications with permanent radiation exposure, such as in flower pots, plastic parts for automobiles, etc
Temperature Characteristics of Magnetoelectric Effect in a Monolithic Langatate-Metglas Heterostructure: The Effect of Annealing
Full text linkMagnetoelectric (ME) effects in ferromagnetic-piezoelectric heterostructures manifest themselves as a change in the polarization of the structure in an external magnetic field or a change in magnetization in an electric field. The effects are used to create magnetic field sensors, tunable electronic devices, and n1 ew data processing elements. To ensure the thermal stability of these devices, it is important to understand the temperature dependence of the ME effect characteristics. In this paper, we investigated the direct resonant ME effect in a monolithic heterostructure consisting of a langatate single crystal with FeBSiC amorphous ferromagnet films deposited on its surface. It was shown that heating of the structure from 220 K to 340 K resulted in a decrease in the quality factor of the acoustic resonance followed by a decrease in the ME coefficient. Annealing the structure in the presence of magnetic field led to an enhancement in the ME coefficient, a decrease in the optimal bias field, and improvement in thermal stability of the ME effect
The Energy Consumption Comparison of Temperature Difference-based Defrosting Exit Method and Time-based Defrosting Exit Method with Various Static Pressure Differences
Full text linkThe time-based defrosting exit method(TDEM) has been widely used in cold storage, but the issue of energy consumption has been heavily criticized. In this paper, a temperature difference-based defrosting exit method(TDDEM) is proposed to compare with TDEM. Firstly, a parameter acquisition system of cold storage is constructed, and the experimental setup is conducted to determine the experimental parameters. Subsequentially, the range of defrosting static pressure difference is determined based on pre-frosting experiment, and the defrosting experiment of TDEM and TDDEM are carried out at five various static pressure difference conditions, 16Pa, 14Pa, 12Pa, 10Pa and 8Pa, respectively. The results show that the temperature fluctuations per defrosting events of TDEM are more severe compared to TDDEM, with with average increases of 102.2%, 91.6%, 59.3%, and 46.5%, respectively. Energy consumptions of TDDEM are markedly lower than TDEM, with reductions of 21.4%, 15.7%, 14.09% and 14.59%, respectively. Whether TDEM or TDDEM, the lowest energy consumption is occurred at 10Pa, and highest is 8Pa
The Research Progress on Photocatalytic Materials for Pollutant Degradation: A Review
Full text linkPhotocatalytic technology, as a clean, green, and sustainable method for pollutant degradation, has significant scientific research value and practical application significance in the field of water pollution control. Currently, the focus of photocatalysis research is on developing efficient, stable, and low-cost photocatalysts. Researchers are enhancing the light absorption capacity, electron-hole separation efficiency, and degradation rate of photocatalysts by designing novel photocatalysts, such as S-type heterojunctions, Z-scheme structures, precious metal doping, and non-metal regulation. The mechanistic study of the photocatalytic process, especially the separation, migration, and transfer mechanisms of photogenerated carriers, provides theoretical support for the optimization design of photocatalysts. At present, there are various types of catalysts for photocatalytic degradation of pollutants, including metal oxide catalysts (e.g., TiO2, ZnO), precious metal catalysts (e.g., platinum, gold, silver), carbon-based catalysts (e.g., graphene, carbon nanotubes), and composite catalysts (e.g., metal oxide-carbon-based composite catalysts).Each type of catalyst has shown performance in improving photocatalytic efficiency and expanding the light absorption range, but also faces challenges such as limited light absorption range, poor catalyst stability, and high cost. Composite catalysts significantly improve photocatalytic efficiency through synergistic effects, especially excelling in the degradation of high-concentration pollutants. Future research will focus on further optimizing the performance of catalysts, particularly expanding the light absorption range, improving electron-hole separation efficiency, and enhancing catalyst stability. The design of composite catalysts remains the focus of research, especially the exploration of synergistic effects between different materials. At the same time, issues such as the long-term stability, recyclability, and selectivity of catalysts need to be addressed to support their large-scale application