Analysis Of System Research Articles

Dynamic analysis of TBM multi-gear parallel transmission system considering the influence of multiple factors

Dynamic analysis of TBM multi-gear parallel transmission system considering the influence of multiple factors

Quantified asymptotic analysis for the relativistic quantum mechanical system with electromagnetic fields

We study the asymptotic analysis of a relativistic quantum mechanical system interacting with self-consistent electromagnetic fields, with a specific focus on the Maxwell–Klein–Gordon (MKG) system. Firstly, we show that the MKG system is globally well-posed under the Coulomb gauge condition, even in the presence of self-interacting potential. Furthermore, to derive the asymptotic analysis, we consider the non-relativistic and semi-classical regime simultaneously, introducing a single scaling parameter that serves to parameterize both the speed of light and the Planck constant. As the scaling parameter approaches zero, we obtain rigorous and quantified estimates on the asymptotic convergence of the electrostatic MKG system toward the classical Euler–Poisson system. Our analytical framework relies on the modulated energy estimate.

GAIT PATTERN INVESTIGATIONS OF BIONIC PIEZOELECTRIC ROBOT

The development of micro-robots based on bionic motion has garnered increasing attention with the advancement of bionic technology. These micro-robots can be employed in various tasks, such as military applications, disaster search and rescue, in vivo drug delivery, minimally invasive surgery, and tumor treatment. Robot joint motion is commonly achieved through actuators, which encompass motor, hydraulic, or pneumatic components that often carry excessive weight. To achieve the goal of miniaturizing robotic mechanisms, innovative actuators need to be developed. This study focuses on designing a four-limbed micro-robot that utilizes piezoelectric actuators. Automatic Dynamic Analysis of the Mechanical System is employed to investigate the kinematic aspects of the micro-robot’s motion, and finite element analysis is also used to obtain the resonant characteristics of the limbs actuated by piezoelectric bimorphs. The results indicate that the gait pattern of a piezoelectric robot changes according to the walking strategy and the robot dimension. The forward travel speed varies depending on the gait pattern, and adjustments in gait design can reduce the up/down oscillation and right/left offset. The robot’s travel speed increases with both trunk and limb length, although longer thigh and leg lengths might lead to greater offset and vertical oscillation. The resonant frequency and mode shapes change with the limb structure and affect the limb motion style. By adjusting the driving frequency of the bimorph actuators, the gait pattern can be manipulated. The information presented in this study contributes to a deeper understanding of micro-robot design.

Research on digital vibration model of typical components in pipe system

The spatial distribution of pipe system is complex, long span and multi-point elastic support, so vibration analysis of pipe system is required in the pipeline design. This paper takes the pipe system as a typical component, based on the Timoshenko beam model, establishes a dynamic procedure for straight pipe elements that considers the axial flow rate of fluid, the pressure on the pipe wall, the Poisson coupling effect of fluid and pipeline structure, and the axial, transverse and torsional vibration. Through Laplace transform, the frequency simplified dynamic model is established. And the frequency transfer matrix model of straight pipe elements and the boundary constraint matrix of common boundary (such as fixed support) is established. Finally, the frequency domain transfer matrix model of different pipeline elements are set to the overall transfer matrix of the flow pipe system, providing a convenient means for rapid optimization of pipe system vibration.

Numerical simulation of a fractional Davey–Stewartson model via a conservative scheme: preservation of mass, energy and momenta

In the present manuscript, we depart from a two-dimensional form of the nonlinear Davey–Stewartson system from fluid dynamics, consisting of two partial differential equations with two unknown functions, one of them is complex-valued and the other real-valued. This model possesses four conserved quantities, namely, the mass, the energy and two momenta. In a first stage, the mathematical model is generalized to the fractional scenario considering Riesz fractional operators and three different orders. We prove mathematically that this system also possesses four quantities that are preserved in time, and which are fractional extensions of the classical mass, energy and momentum operators. Motivated by this fact, we introduce a numerical scheme for the mathematical model by making use of fractional-order centred differences. By using similar arguments as in the analysis of the continuous system, we propose some discretizations of the mass, the energy and the momenta, and we proved theoretically that these quantities are also conserved in the discrete case. In our theoretical analysis, we establish mathematically the properties of consistency for the mathematical model as well as for the discrete conserved quantities. Computationally, the finite-difference scheme is implemented using a fixed-point algorithm. Various computer simulations are performed to illustrate the conservation of the discrete quantities. Finally, we provide some interesting perspectives of research at the end of this work. This report is the first work in which a conservative finite-difference scheme for the Davey–Stewartson system is designed and rigorously analysed for the conservation properties, for both the integer-order and fractional cases.

Vibration analysis of piping system coupled with conical-cylindrical combined shells

Fluid-filled piping system are widely used in power cooling, fuel transportation and underwater vessel, which not only produce vibration along the system, but also transmit to the connecting structure to generate noise in ambient environment. Most investigations have concentrated on either the vibration characteristics of piping systems or of combined shells separately. In this work, an analytical impedance synthesis method (ISM) is proposed to analyze the vibration characteristics of a pipe-hull coupled system, in which the hull can be simplified to a combined conical-stiffened cylindrical-hemisphere shell. The piping system is modeled by fluid-filled beams in three-dimensional configuration. Wave function and power series solution are used to describe the displacements of cylindrical and conical shell respectively. Based on exact analytical solutions, the impedance matrix of each segment is established separately and assembled in the global coordinate by displacement continuity and force balance boundary conditions. Forced responses are compared with the experimental results to verify the correctness of the method.

Secrecy and performance analysis of dual hop FSO-RF system using differential chaos shift keying

Secrecy and performance analysis of dual hop FSO-RF system using differential chaos shift keying

Animal-free safety assessment of chemicals: an innovation system perspective.

This perspective paper, which is the result of a collaborative effort between toxicologists and scholars in innovation and transition studies, presents a heuristic framework based on innovation system literature for understanding and appraising mission achievement to animal-free chemical safety assessment using New Approach Methodologies (NAMs). While scientific and technical challenges in this area are relatively well known, the recent establishment of missions and roadmaps to accelerate the acceptance and effective use of NAMs for chemical safety assessment raises new questions about how we can grasp the systemic nature of all changes needed in this transition. This includes recognising broader societal, institutional, and regulatory shifts necessary for NAM acceptance and uptake. Our paper discusses how the innovation system approach offers insights into key processes and associated activities that include as well as transcend the technical and scientific realm, and can help to accelerate acceptance and uptake of NAMs. Based on these insights, we present a comprehensive framework that, next to scientific and technological developments, recognises the need for coordinated efforts in areas like education, training, funding, policy-making, and public engagement to promote the acceptance and uptake of NAMs. Our framework can be used to perform structural and functional analyses of the innovation system of NAMs and animal-free safety assessment and as such provides handholds to track progress and organise collective efforts of actors to make sure we are moving in the right direction.

Theoretical and experimental analysis of a nonlinear vibro-acoustic energy sink

This study is concerned with the experimental and theoretical analysis of a vibroacoustic nonlinear system devoted to absorption application. Based on the nonlinear energy sink principle, the dynamics of the system is reduced to two coupled degrees of freedom, one of which exhibits nonlinear behavior due to a large displacement mechanism. The set-up allows for precisely characterizing the nonlinear function of the mechanical system, first uncoupled and then coupled with an acoustic and linear resonator. Continuation procedures are performed experimentally and numerically, respectively using a phase-locked loop (PLL) and the asymptotic numerical method implemented in the MANLAB software package. The comparison between theoretical predictions and experimental results obtained on the uncoupled system allows for a parameter identification of the nonlinear resonator. Measurements on the coupled system highlight the energy pumping phenomenon, which can be predicted from numerical predictions in which identified parameters are introduced. The procedure aims at proposing analytical models for achieving efficient level attenuation, and providing design guidelines for sound reduction at high levels in confined spaces.

Optimized position analysis of multi-directional active mounting system based on quantification formula

This paper mainly studies the influence of active mounting system for vehicle engine vibration from both theoretical and experimental aspects. First, an active mounting system that considers both horizontal and vertical directions is proposed, modeled, analyzed and verified. The structure contains a bent beam representing the engine, two sets of actuator and elastomer forming active paths, and a straight beam representing the chassis. Second, the force and phase of the active mounts at each location combination are calculated based on static and dynamic methods. The dynamic analysis method is used to examine how the control signal changes with the input signal to learn the correlation between them. The static analysis is employed to obtain the change in force applied to the paths when the position of the input signal changes and to find the optimized placement criteria. Through the position relationship between force and mounting, a specific position where the applied force is relatively small was considered the optimized position of the active mounting system. Finally, these criteria were verified with experiments and the results are matched well with each other.

Performance analysis of heat pump drying system combined with rotor dehumidification for low temperature drying of mango slices

In order to solve the problems of low drying efficiency and poor drying quality existing in the current closed heat pump drying system (CHPD), a closed carbon dioxide heat pump drying system (CHPRD) with the function of combining rotor dehumidification was designed. This study investigates the drying kinetics and quality characteristics of CHPRD in low-temperature drying processes using mango as the drying material through experimental studies and theoretical analysis. The experimental results showed that the drying rate of CHPRD increased by 29% and 17.8%, the moisture removal rate per unit energy (SMER) by 14.2% and 12.5%, and the coefficient of performance (COP) by 17.3% and 12.0%, respectively, compared with that of CHPD in the low-temperature drying process with loading amounts of 400 and 450 g, respectively. In terms of drying quality, the rehydration factor (Rf ) of CHPRD-dried mango slices increased by 6.0% and 5.0%, the ascorbic acid content increased by 15.0% and 14.4%, and the color difference (ΔE) was lower by 11.0% and 5.6%, respectively. These improvements indicate that CHPRD provides better drying kinetics and higher quality of dried material. Based on the experimental data, simulation fitting was conducted, revealing that the two-term model is the best mathematical model to simulate the drying characteristics of CHPRD for mango.

Novel Ceramic Clay Automatic Feeding System and Simulation Analysis

This study aims to verify the feasibility and effectiveness of an automatic feeding system in the ceramic clay-forming process. Through a series of clay-forming experiments, the system’s performance under various process parameters was examined. Precision sensors and data recording devices were used to monitor and record key data during the experimental process in real-time. The results demonstrate that the automatic feeding system can supply clay steadily and continuously under set parameters, ensuring a smooth forming process and significantly improving efficiency. Quantitatively, the system achieved a 30% increase in Vickers hardness, reflecting enhanced mechanical properties of the formed clay bodies. Additionally, there was a notable improvement in axial stress–strain characteristics, indicating better structural integrity and consistency. These improvements reduced human errors and material waste, enhancing production efficiency and product quality. Future research will focus on further optimizing system design and exploring its applications in a broader range of ceramic manufacturing processes.

Development of an expert system for technological support of required roughness when machining hardened steel parts on numerically controlled machines

This work addresses the problem of improving the surface quality of parts of rotation bodies, which are made of hardened steels, in the course of their machining on lathes with numerical program control. The research object was the surface roughness of parts. The methodology involved system analysis and synthesis, artificial neural networks, fuzzy logic, experiment, and processing of experimental results. A decomposition scheme for the expert system structure was developed, which can be used as the basis for formulating requirements to a future expert system for monitoring and prediction of roughness parameters. It was established that the models currently applied to describe the relationship between surface quality and the technological regimes used to ensure the technological level of roughness give a high error of over 20%. The possibility of using models that apply artificial intelligence and contain neural network blocks and decision-making devices based on fuzzy logic is substantiated. It is shown that such a combination makes it possible to customize the system for processing parts of a certain production range, as well as a more correct assessment of the onset of catastrophic wear of cutting tools. The neuro-fuzzy model was confirmed to have an error of less than 10%, which is significantly lower than when using spectral or correlation models. According to the testing results, the proposed expert system for monitoring and prediction of roughness parameters enables a 2.5-fold reduction in the scatter of roughness parameters under an increase in tool wear, compared to without its application. Thus, the proposed system makes it possible to assess the level of cutting tool wear more correctly and determine the onset of its limit state.

Paradigm shift in mechanical system design: toward automated and collaborative design with digital twin web

AbstractAnalyzing multi-vendor mechanical system designs requires a significant amount of manual work, resulting in a design paradigm where analysis is conducted only after the design is locked and components are selected. This leads to a suboptimal design with compatibility issues, over-dimensioned components, inferior performance, poor energy efficiency, and a lack of collaboration between OEMs (original equipment manufacturers) and system integrators. To overcome these issues, this paper proposes Co-Des (collaborative design) framework for automated and collaborative multi-vendor system design. The framework relies on standardized digital twin documents (DTD) of system designs, components, and analyses. The discoverability and distribution of these DTDs are enabled with digital twin web (DTW). Co-Des framework allows for finding suitable components for the design task by automatically running selected analyses employing component digital twins. In addition, OEMs can provide customized components for system integrators using the initial system design defined in the system design DTD. The use of the Co-Des framework was demonstrated with a windmill powertrain design use case, and the applicability of the automated assembly analysis for component selection was verified with performance measurements. The adoption of the proposed framework will lead to a paradigm shift from manual and siloed work relying on the exchange of PDFs to a more automated and collaborative design of mechanical systems. The adoption rate is defined by the willingness of system integrators to publish their initial system designs and OEMs their components as public digital twins.

Разработка подхода к интегрированному планированию в цепочках поставок приборостроительной отрасли

Purpose: the article proposes an approach to integrated planning in supply chains of the instrument-making industry, aimed at improving the efficiency of coordination between their main participants. Methods: the study used methods of system analysis, statistical analysis and expert assessments, which made it possible to evaluate current approaches to planning and propose an approach to integrated planning based on modern digital technologies used in the performance of the planning function. To obtain the results of the study, official statistical data on the productivity and economic indicators of the instrument-making industry, data on logistics operations and supply chains of various enterprises in the industry were used. Results: the main scientific result is the approach to the development of integrated planning in supply chains developed by the author. The study also provided practical recommendations on the use of management methods at different stages of the formation of an integrated planning system. Practical significance: the practical significance of the study lies in the possibility of applying the proposed recommendations at enterprises of the instrument-making industry to improve the efficiency of supply chain management. The implementation of the developed methods will allow enterprises to adapt to dynamic market conditions, reduce costs and improve coordination of the actions of private logistics chain participants. The results of the study can be used to develop and improve planning systems in organizations in the instrument-making industry.

Reliability analysis of subsea manifold system using FMECA and FFTA

Subsea manifold system is a complex system that occupies a pivotal role in contemporary ocean engineering and has a significant impact on the safety of marine resource exploitation. Reliability technology plays a significant role in ensuring the safe operation of the subsea manifold system. To perform a comprehensive analysis of the reliability of complex systems, a combination method of FMECA-FFTA (Failure Modes, Effects and Criticality Analysis - Fuzzy Fault Tree Analysis) is introduced in this study. Firstly, FMECA is used to accomplish a qualitative analysis of system reliability considering multifactorial failure modes, which included analyzing potential failure modes, causes of system failure, and evaluating the degree of hazard to the system through a risk matrix diagram. Then, FFTA is applied to build a fault tree model to divide the system into “system-subsystem-component” and determine the minimal cut sets for quantitative analysis of system reliability. In addition, fuzzy set theory is incorporated to improve the accuracy of handling uncertainty in quantitative reliability analysis. Finally, a qualitative and quantitative reliability analysis is conducted by using FMECA-FFTA method for subsea manifold system. The failure modes of the subsea manifold system are clearly identified, including high-risk modes such as external leakage, medium-high-risk modes such as fail to close/lock on demand, and medium-risk modes such as leakage of critical location, plugged, and effective measures should be taken to focus on preventive protection and regular testing for the high risk, medium-high risk and medium risk modes.

Conservation of Hindu Religious Lontar Manuscripts Through Lontar Digitization Website Information System in Tabanan Regency

Lontar as a cultural product is rich in meaning and raised the image of balinese traditions in the world civilization. The existence of lontar tradition nowadays in Tabanan Regency has a long and old history complemented by historical, religious, philosophical, medicinal, literary, and other great scientific values. This research aims to 1) conserve and digitize lontar in Tabanan Regency, and 2) create a website information system for digitizing lontar in Tabanan Regency. The research methods employed are palm conservation, system analysis, system planning, system design and system testing. The results of the research showed that 1) the conservation and digitalization of lontar was carried out in Tabanan can save the lontar, to keep it in a good condition, not damaged by termites or rodents, so it can continue to be passed on to the next generation as a reflection of the past about the medicine, ceremonies, religion, arts, and culture. 2) The lontar digitization website information system can be used as a guide for the public regarding lontar information and contents. In conclusion, the saving of Hindu religious lontar manuscripts through the lontar digitalization website information system in Tabanan Regency is carried out in the form of conservation and the creation of a lontar digitalization website information system, to make it accessible for the entire community online. In terms of culture, it can be passed down to the next generation as a form of cultural and religious preservation including medicine, ceremony, religion, art, and culture. The development of information system for the lontar digitization website is very good and important to save Hindu religious lontar manuscripts.

Effects of racial teasing on adolescent marijuana use and nicotine vaping: An analysis of the Virginia Youth Risk Behavior Surveillance System

BackgroundDespite adverse effects of tobacco and marijuana use on the adolescent brain, its use among youth remains high. Previous research shows associations between bullying and risks of substance use; less is known about racial teasing. This study examines associations of racial teasing, marijuana and/or electronic vapor products (EVP) use among adolescents, using 2021 Virginia Youth Risk Behavior Surveillance System (VYRBSS). MethodsVYRBSS is a self-reported survey which collects information on experiences with racial teasing and substance use. This analysis included 3,083 high school students ≥ 12 years old. Descriptive analysis and logistic regression models were performed for categorical variables. Multivariable models were adjusted for confounders. ResultsRacial teasing was associated with marijuana (AOR 1.89; CI 1.43–2.48) and EVP use (AOR 2.52; CI 1.91–3.31). Compared to Whites; Asians, Blacks, and Latinos were more likely to report racial teasing. Older heterosexual females reported higher use of marijuana and EVP. Blacks reported greater use of marijuana, whereas Whites were more likely to use EVP. EVP use was higher in females (AOR 1.73, CI 1.34–2.23), bisexual youth (AOR 1.68, CI 1.23, 2.30) and poor mental health (AOR 1.49, CI 1.16, 1.92). Marijuana use was associated with bisexuality (AOR 1.75, CI 1.28–2.39) and poor mental health (AOR 1.62, CI 1.27–2.07) as well. ConclusionsEvery effort should be made by public health professionals in Virginia to prevent racial teasing among adolescents because it increases the odds of substance use, particularly in older females, youth who identify as bisexual, and those reporting poor mental health.

Analysis of a constant-volume diafiltration system with the ability to remove lithium cations when using poly(2-acrylamido-2-methyl-1-propanesulfonic acid) in water

This study describes the synthesis of a poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) and its application for the removal of Li+ in water using a constant-volume diafiltration system. PAMPS with molecular weights exceeding 100 kDa (88 % w/w), polymerisation yields of 97 % and high acidity was obtained. A block experimental design characterized the diafiltration system reporting: Regenerated cellulose (RC) and polyethersulfone (PES) ultrafiltration membranes with a molecular cut-off of 100 kDa can retain up to 1 % Li+ ions through surface charges. But when PAMPS 2000 kDa was used, 89 % of Li+ was removed (%R). Permeate flux (Js) decreases with increasing PAMPS:Li+ ratio, whereas the %R value increases. The filtration process is controlled by diffusion mechanisms according to the Peclet dimensionless number. Using PAMPS 100 kDa with a PAMPS:Li+ ratio (20:1), %R decreases to 76 %, whereas Js increases slightly. PAMPS can be reused 3 consecutive times, maintaining a Li+ cation rejection efficiency of >60 %. Additionally, it was found that the percentage of Li+ rejection capacity exercised with PAMPS is reduced to 60 % when Ca2+, K+, Mg2+ and Na+ cations are present.

Thermo-economic investigation and comparative multi-objective optimization of dual-pressure evaporation ORC using binary zeotropic mixtures as working fluids for geothermal energy application

This contribution performs an energy, exergy, and exergoeconomic (3E) analysis of a dual-pressure evaporation organic Rankine cycle system employing twenty different binary zeotropic mixtures as working fluids for power production from a geothermal field. To this end, the designed system is modeled, invoking the mass and energy conservation laws and the exergy and cost balance analyses. Specific Exergy Costing (SPECO) procedure is utilized to provide practical insights into the exergoeconomic aspect of the system. Comparative optimization based on the multi-objective genetic algorithm is accomplished for each mixture in order to simultaneously maximize the exergy efficiency and minimize the total cost rate using the design variables of pressure factor in low-pressure and high-pressure stages, mixture fraction, pinch point temperature differences in low-pressure and high-pressure heat exchangers, and degree of superheat in the high-pressure heat exchanger. In this regard, the Pareto frontiers are drawn for the system with all twenty different binary zeotropic mixtures. The optimal point for each mixture is obtained via the decision-making technique of LINMAP. Subsequently, the LINMAP is re-utilized to find the preferred mixture. The optimization results suggest the R123/C2Butene (96.89/3.11) mixture for this system as the optimum working fluid, considering a trade-off between a low-cost rate of $88.0651 per hr and a high exergy efficiency of 64.07 %. Finally, the exergy flow diagram is plotted to provide the exergy flow rate and the amount of exergy destruction in each segment of the system considering the optimal working fluid. In the proposed system, exergy destruction chiefly occurs within the low-pressure preheater with a value of 1061 kW, followed by the low-pressure turbine and condenser with magnitudes of about 669 kW and 266 kW, respectively.