Comprehensive Performance Index Research Articles

Research on the comprehensive evaluating index of seismic performance of underground large-scale frame structures

This paper proposes the comprehensive evaluating index of seismic performance of the underground large-scale frame structure (ULSFS), based on the structural failure mechanism of the entire structure and local components. The ULSFS employed is used in underground supermarket construction, and it has an extremely large-scale in two horizontal directions. During different earthquakes, the structural seismic responses are investigated, and vulnerable positions and failure mechanisms of the ULSFS are further revealed by the shear-axial compression ratio and shear-span-to-depth ratio. The inter-layer drift ratio (IDR) aims at the entire structural deformation, and the inter-layer rotation angle (IRA) aims at the local component damage. Corresponding to the failure mechanism, the seismic weights of two evaluating indexes are achieved by employing the Entropy Weight Method, and the variation rules of seismic weights on columns in different performance stages are revealed. On account of seismic weights, the Inter-layer Deformation (ID), combined with the IDR and IRA, is proposed to be the comprehensive seismic performance index for the ULSFS. Moreover, the seismic influence effects of the soil elastic modulus on the seismic performance are clarified. The paper reveals the inside structure undergoes the great inter-layer drift deformation because of soil horizontal deformation, and the outside structure undergoes the considerable flexural deformation due to soil-structure interaction. The ID can both evaluate the inter-layer drift deformation and flexural deformation based on the combination of IDR and IRA. The universal threshold values of the ID are proposed to be 0.5/1000, 1/1000, 3.3/1000, 6.6/1000 in the different seismic performance stages for the ULSFS.

The influence of catchment scale on comprehensive heat transfer performance about tube fin heat exchanger in numerical calculation

The purpose of enhanced heat exchange technology is to improve the heat exchange performance of heat exchange equipment, but the increase of resistance causes the decrease of energy consumption and economic benefits. Then the comprehensive evaluation index is used to evaluate the comprehensive heat exchange performance of heat exchange equipment. In the process of numerical simulation, there is no unified standard for the value of the catchment scale. In this paper, by changing the length of the entrance and exit of the external passage of the tube-fin heat exchanger, the change law of comprehensive heat transfer performance index (j⋅f−1/3) for heat exchanger at different Reynolds numbers was studied by numerical simulation. The results show that the heat transfer effect is better than that without extension, and the effect is the best when it is 1.5 times, and the growth rate is more than 1.5%; compared with the non extended conditions, the extended outlet basin has little impact, and the maximum increase of c comprehensive heat transfer performance index (j⋅f−1/3) is no more than 0.75%. Therefore, in the numerical simulation, the inlet of the external basin of the heat exchanger can be extended by 1.5 times of the base tube diameter, and the outlet is not extended.

Hydrodynamics of recirculating aquaculture tanks with different spatial utilization

In order to maximize the spatial utilization of Recirculating Aquaculture System (RAS) and improve conditions for the growth of farm-raised species, the hydraulic performances of a single-channel RAS with different spatial utilization were researched. A numerical simulation model was established by reference to the experimental model, and the validity of the method was verified by comparing it with the experimental results. Firstly, three-dimensional unsteady models were established by replacing a rectangular tank with a circular arc tank. Then, the hydrodynamics of recirculating aquaculture tanks were analyzed, including velocity distribution, vorticity strength, energy effective utilization coefficient, and the flow uniformity index. Furthermore, flow characteristics, including the evolution of turbulent structures and the relevant influence factors, were also analyzed. Finally, a comprehensive performance index was proposed, which can effectively evaluate the spatial utilization and hydrodynamic characteristics for different aquaculture tanks. The results indicate that with the increase in fillet radius of the tanks, the turbulence intensity in the flow field gradually weakens. The generations of low-speed mixing zone of the culture tank are significantly improved, and the flow uniformity index shows an overall upward trend. In addition, there is a positive correlation between the effective energy utilization coefficient and the flow uniformity index. When spatial utilization of the tank is in the range of 95.3–98.4%, the comprehensive performance index is relatively large. Such an inclusive analysis explores the hydrodynamics in the aquaculture tanks with different structures and recommends the maximization of space utilization.

Potential Analysis and Optimization of Combined Cooling, Heating, and Power (CCHP) Systems for Eco-Campus Design Based on Comprehensive Performance Assessment

At present, countries all around the world have implemented energy-saving and emission reduction measures to achieve carbon neutralization. The combined cooling, heating, and power (CCHP) system is a high-efficiency energy system that can promote energy-saving and decrease carbon emissions. The choices of installed capacity and operation strategies impacts the economy, energy-saving, and environmental protection of combined cooling, heating, and power systems. The aim of this study was to determine the potential and comprehensive benefits of combined cooling, heating, and power systems based on the comprehensive performance assessment. In this study, a comprehensive performance index (CPI) method was presented to optimize the configurations and operation strategies of combined cooling, heating, and power systems in a Japan eco-campus, based on historically monitored data. According to the influencing factors of the combined cooling, heating, and power system in comprehensive performance index evaluation, the adaptability and development potential of economy, energy saving, and CO2 emission reduction were evaluated to consider future renovation of energy systems. In this study, we adopted a seasonal time-of-use (STOU) electricity price to evaluate the economic performance of combined cooling, heating, and power systems and compared them to the time-of-use (TOU) electricity price. The results indicated that the seasonal time-of-use electricity price was more economic in regions that had high cooling demand in summer. By comparing the CO2 emission coefficient of electricity in different regions in Japan, we could estimate that more than 40% of the cleaner energy ratio was positive. The results obtained can provide suggestions for the future development of combined cooling, heating, and power systems.

Co-Combustion Characteristics of Typical Biomass and Coal Blends by Thermogravimetric Analysis

In this study, the co-combustion characteristics of coal and biomass blends (20, 40, 60, 80, and 100 wt%) were investigated by thermogravimetric analysis. All the samples were operated under an oxidative atmosphere, with a heating rate of 20 C/min. The reaction stages, ignition and burnout temperature, maximum weight loss rate, and different combustion indices were determined. When the percentage of biomass in the blends was increased, the maximum mass loss rate was enhanced in the second region, and the ignition and burnout temperature was lowered, indicating the higher reactivity and better combustion performance of the samples. The comprehensive performance index presented an N shape with the increasing biomass blending ratio. Based on various combustion indices, 20% was an optimum percentage for the co-utilization of coal-biomass blends. A significant promoting interaction was observed between corn straw and rice straw blends, while inhibiting effects occurred between rice husk and coal. The kinetic parameters of the blends were evaluated by the Coats and Redfern method using the nth-order reaction model. The value of activation energy and the pre-exponential factor increased with the decreasing biomass percentage in the blends.

基于气送定量供种的气吸式辣椒排种器设计与试验

In order to solve the problem that the current precision seeder has difficulty in precision sowing pepper seeds, an air-suction pepper seed metering device based on air supply and quantitative seed supply was developed. Combined with its basic structure and working principle, the CFD-DEM coupling method was used for analysis, and the best combined hole parameters were obtained. A single factor experiment with the pass rate, replay rate, and missed rate as experimental indicators was designed. Regression model was established to obtain a reasonable range of each parameter. The results showed that when the speed of the drum barrel was 28.65r/min and the working negative pressure was 4.40kPa, the seeding pass rate of the seed meter was 91.32%, the replay rate was 4.51%, and the missed rate was 4.17%. The comprehensive performance index was better.

Multi-objective optimal design of a novel 6-DOF spray-painting robot

AbstractThis paper deals with the multi-objective optimal design of a novel 6-degree of freedom (DOF) hybrid spray-painting robot. Its kinematic model is obtained by dividing it into serial and parallel parts. The dynamic equation is formulated by virtual work principle. A performance index for evaluating the compactness of robot is presented. Taking compactness, motion/force transmissibility, and energy consumption as performance indices, the optimal geometric parameters of the robot are selected in the Pareto-optimal set by constructing a comprehensive performance index. This paper is very useful for the development of the spray-painting robot.

Design and Optimization of Robust Path Tracking Control for Autonomous Vehicles With Fuzzy Uncertainty

Uncertainty is a major concern in vehicle path tracking control design. The coefficients of the uncertainty bound are unknown. They are assumed to lie within prescribed fuzzy sets. First, based on the path tracking kinematic model, this paper innovatively formulates the vehicle path tracking task as a constraint-following problem. Second, we put forward a deterministic adaptive robust control law with a tunable parameter to ensure the uniform boundedness and ultimate uniform boundedness of the closed-loop system. Third, an optimal scheme for the tunable parameter is proposed based on the fuzzy uncertainty. The resulting optimal robust control (ORC) minimizes a comprehensive fuzzy performance index that involves the fuzzy system performance and the control cost. The results of the CarSim-Simulink co-simulation and the Hardware-in-loop (HIL) experiment together show that the proposed optimal robust control exhibits a superior path tracking performance.

Impact Performance Optimization of Serial Metamorphic Robot Based on Comprehensive Performance Index

Impact Performance Optimization of Serial Metamorphic Robot Based on Comprehensive Performance Index

Link Lengths Optimization Based on Multiple Performance Indexes of Anthropomorphic Manipulators

How to determine the optimal link length parameters according to task requirements and constraints is a key problem in the design of anthropomorphic manipulators. Considering multiple performance indexes such as dexterity and end stiffness, this article presents a method on how to maximally improve the comprehensive motion performance of anthropomorphic manipulators by optimizing the link lengths. Firstly, the joint motion ranges of human arm are obtained through analyzing the motion mechanism and the motion forms. Then the kinematics model of manipulators with the optimal configuration is established by using screw theory, and a comprehensive evaluation index for the motion performance is proposed by considering the Jacobian matrix condition number, manipulability, and end stiffness. Taking the evaluation index as the objective function, the corresponding constraints and the optimization model are established to optimize the link lengths of manipulators with both flexibility and stiffness. Through comparative analyses, it can be seen that the global comprehensive performance index value of the optimized anthropomorphic manipulators increases by about 23.97%, and the motion performance is significantly improved.

Effect of air supply mode on airflow distribution in winter train sleeper compartments

Few of existing literatures on the airflow distribution of compartments have studied combined applications of radiant heating and air conditioning in winter. Simulation of airflow distribution in 25 T soft sleeper compartments under different heating and ventilation schemes is provided in this paper. Firstly, reliability of the numerical simulation model has been verified by the experimental data in the literature, and the appropriate turbulence model has been selected. Afterwards, numerical simulations are carried out on airflow distribution in those compartments with four ventilation modes under radiant heating conditions in winter. Research results show that as for thermal comfort, task air supply can provide the smallest temperature difference between head and foot positions as well as the best thermal comfort. As for effectiveness of air supply, the ventilation efficiency of louver side air supply is the highest among others. As for effectiveness of pollutant removal, the ventilation efficiency of task air supply is higher than the other three options. These four heating and ventilation schemes are evaluated comprehensively with fuzzy comprehensive evaluation method. Results reveal that task air supply is the mode with best comprehensive performance indices. It is followed, respectively, by louver side air supply, perforated ceiling air supply and louver top air supply.

Decision support for scenario analysis in a complex water resource project

Multi-criteria decision support (MCDS) was developed and demonstrated for a complex reservoir system for a comprehensive assessment of performance for a complex reservoir system. A management model for the Tandula complex system in India was developed in MIKE HYDRO Basin. This system has three interconnected reservoirs, three irrigation commands, and one industrial user. The results from simulations were analyzed in multi-criteria decision support using an economic and six performance indicators to get a comprehensive performance index for the system. The results of the analysis confirmed that the yearly deficit of the Tandula command maybe about 6.36 MCM with 88% reliability under the present efficiency of 51% and no groundwater use (SCN-1). The comprehensive performance index for scenario SCN-1 was 0.13 which can be increased to 0.86 by increasing efficiencies and consumptive use. Abbreviations: AHP: Analytical hierarchical process; ANN: Artificial Neural Network; BSP: Bhilai Steel Plant; CEA: Cost effectiveness analysis; DAPP: Dynamic adaptive policy pathways; DS: Decision scaling; GW: Groundwater; Ha: Hectare; MORDM: Many objective robust decision making; MOVA: Many-objective visual analytics; MCDA: Multi Criteria Decision Analysis; MCM: Million cubic meter; MCDA: Multi-criteria decision analysis; NB-DSS: Nile Basin Decision Support System; ROA: Real options analysis; RRV: Reliability, resilience, vulnerability; RDM: Robust decision making; WEAP: Water Evaluation and Planning; SCN: Scenario; VIDEO Visually interactive decision-making and design using evolutionary multi-objective optimization

Comprehensive validation of the latest IMERG V06 precipitation estimates over a basin coupled with coastal locations, tropical climate and hill-karst combined landform

The version 6 (V06) of Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG) provides three products and their Satellite Estimates (SE) has three different temporal resolution. As the study area, the Nanliujiang River Basin (NRB) located in the coastal tropics of southern China has a hill-karst combined landform. Based on the Ground Observations (GO) from 14 gauges of NRB, the SE of three IMERG products with the highest resolution of 0.5 h are evaluated under 12 days. Then, by selecting daily SE, IMERG V06 is compared with its previous version (i.e., V05) from December 2016 to November 2017 while monthly SE of IMERG V06 are compared with that of TMPA 3B43 from 2008 to 2014. Besides the ordinary evaluation of the detection capability, correlation and error, a metric called Comprehensive Performance Index (CPI) is introduced to show the overall performance of the products. The main results of the comprehensive validation are that (1) IMERG keeps higher detection capability under low precipitation thresholds at the basin- or grid-scale. The diurnal variation of three 0.5 h products' rainfall detection becomes obvious with threshold increasing. The advantage of IMERG V06 products over V05 in rainfall detection is small. (2) IMERG Final Run (IMERG-F) half-hourly product of V06 shows a high correlation with GO than the two near-real-time products at the partial gauges and dates. IMERG V06 outperforms than V05 or TMPA 3B43 on correlation at the basin-scale and partial gauges. (3) Main form of the biases presented in the validation of three IMERG products at 0.5 h resolution and the comparison of IMERG V06 to other daily or monthly satellite products are reflected as rainfall overestimation and underestimation, respectively. Compared with V05 and 3B43, biases in the relatively cold and dry season are significantly improved by V06. (4) IMERG cannot reflect the spatial distribution of average precipitation with high values. The performance of SE changing between different gauges, which is shown as the spatial variability. (5) The number of gauges where IMERG-F of V06 has higher (or the highest) CPI values is the largest among each product combination of validation.

Tank-Level Control of Liquefied Natural Gas Carrier Based on Gaussian Function Nonlinear Decoration

This paper introduces a novel controller into the tank level control of liquefied natural gas (LNG) carrier. The proposed controller can simplify the design process and save energy output of the controller under the premise of achieving a good control effect of the liquid level of a liquefied natural gas (LNG) carrier tank. Moreover, Gaussian function is adopted to decorate nonlinearly the output of the linear controller designed by using the second-order closed loop gain-shaping algorithm, and then the final controller is obtained. The effectiveness of the controller is verified by simulation experiments on the LNG carrier ‘‘Da-Peng Sun’’ No.2 liquid tank. The simulation results show that the comprehensive control performance index J of the second-order closed loop gain-shaping controller decorated by Gaussian function reduces by 11.8% and 95.3%, respectively, compared with the controller without nonlinear decoration and the linear proportional–integral–differential (PID) controller, meeting the requirement of energy saving and realizing a good control result of the tank level of the LNG carrier.

Multi-objective optimization of combined cooling, heating, and power systems with supercritical CO2 recompression Brayton cycle

The supercritical CO2 Brayton power cycle is considered as a promising primary mover of the combined cooling, heating, and power system to potentially provide higher efficiency. This paper presents a novel combined cooling, heating, and power system with a supercritical CO2 Brayton cycle as the primary mover, wherein a part of heat that was originally released in the low temperature recuperator and a part of heat that was originally released to the environment are recovered for heating or cooling. The comprehensive performance is evaluated by identifying the Pareto frontier through the multi-objective genetic algorithm method and determining the optimal solution through the Technique for Order Preference by Similarity to Ideal Solution method. Results demonstrate that it is better to locate the heating/cooling heat exchanger before the flow split for both the heating and cooling modes. The two combined cooling, heating, and power systems always outperformed the basic system in terms of economic and comprehensive performances in heating mode. In particular, the comprehensive performance index of the proposed novel system was up to 31% higher than that of the basic system. We found that the supercritical CO2 recompression Brayton system should not be combined with the heat–driven cooling cycle in most circumstances. The proposed combined cooling, heating, and power system gave a better comprehensive performance only in the range of the cooling to power ratio 1.37–1.53 when taking the electricity efficiency and total product unit cost as the optimization objectives with a weight of (0.5, 0.5).

Pressure drop and heat transfer performance of microchannel heat exchanger with different reentrant cavities

The shape of the reentrant cavities has a great effect on the pressure drop and heat transfer performance of microchannel heat exchanger (MHE). In present study, MHEs with three reentrant cavity, i.e. circular, trapezoidal, and rectangular, were designed and manufactured. The influence of the cavity shape on the pressure drop performance, heat transfer performance and comprehensive performance of the MHEs were investigated. The pressure drop and Darcy friction coefficients were largest for the rectangular reentrant cavities, indicating that it exhibited the best pressure drop performance. At the same flow rate, the MHE with circular reentrant cavities had the lowest hot water outlet temperature and the MHE with rectangular reentrant cavities had the highest temperature, whereas the results were the opposite for the cold water outlet temperature. The Nusselt number was largest for the circular reentrant cavities. This indicates that the MHE with circular reentrant cavities had the best heat performance. Finally, the comprehensive performance index η was put forward. And the result found that the MHE with circular reentrant cavities had the highest comprehensive performance.

Experimental study on thermal efficiency improvement using nanofluids in heat sink with heated circular cylinder

Thermal efficiency is applied to research the hydraulic and thermal characteristics of nanofluids flowing around the heated circular cylinders with vertical fin in heat sink. The influences of fin heights (H = 2 mm, 3 mm, 4 mm) on the thermo-hydraulic characteristics of Fe3O4-water nanofluids are explored. Moreover, the influences of nano-particle mass fractions (ω = 0.0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%) and Reynolds numbers (Re = 491–1223) are investigated. Research shows that nanoparticle mass fraction (ω = 0.4%) and fin height (H = 3 mm) are the most suitable working conditions for the best heat exchange performance. Furthermore, the thermal efficiency and comprehensive performance index have been used to investigate the comprehensive cooling characteristics of the fin structures and nanofluids in the heat exchange system. It is discovered that thermal efficiency increases with the fin height. Comprehensive performance of the heat exchange system is significantly enhanced by the fin structure in circular cylinder.

Effect of squid fin bionic surface and magnetic nanofluids on CPU cooling performance under magnetic field

AbstractIn order to improve the low cooling efficiency of electronic component, a squid fin bionic surface and composite magnetic nanofluids were developed and applied in CPU cooling. Effects of squid fin bionic surface and composite nanofluids Fe3O4‐CNTs (FCNT)/water nanofluids on CPU cooling performance under magnetic field were systematically studied. The impacts of nanofluids mass fraction, wave frequency of squid fin bionic surface, magnetic induction intensity, and Reynolds number on the flow and heat exchange characteristics of magnetic nanofluids were considered. The experimental results demonstrated that the cooling capacity of magnetic nanofluids increases with the increasing wave frequency, magnetic induction intensity, and nanofluids mass fraction. Lastly, the whole experimental system was evaluated by a comprehensive performance index, and it was found that the comprehensive performance is better with higher wave frequency and stronger magnetic field.

Determination of Maintenance Time of Radar Seeker Based on ABC Method

According to the health state grade classification standard of seeker and the corresponding performance state description, the health state grade corresponding to the predicted value of performance index parameters of transmitter and antenna servo mechanism is evaluated. As a result, the health status grade of the seeker system is obtained. In order to determine the maintenance time of the seeker more accurately, the comprehensive performance index of the seeker in the stage of “deterioration” is divided by the application of ABC analysis rule. Finally, the best maintenance time of seeker is determined by calculation.

Optimization design of the in-place-machining tool beam for FRPs bonded repair

Inward-bonded Patch technology is a common method for repairing defects and damage of (Fiber Reinforce Plastics) FRP parts. In the project, there is an urgent need for an in-situ machining machine with a concave step structure in the method. Such thin-walled, weakly rigid parts are easily deformed under pressure. Therefore, the machine beam is lightly designed to reduce the influence of compression deformation on the machining quality. In this paper, the annular (basalt fiber polymer composite) BFPC beam of a certain type of in-situ machining machine prototype is taken as the research object. Firstly, based on the analysis of the prototype working conditions, the comprehensive performance index of the beam is clarified. Using the topology optimization technology, the beam topology of the optimal topology is obtained. Finally, the establishment is established. The multi-objective optimization function with regular structural parameters as variables and minimum beam quality and deformation as the target has obtained the optimal topology and optimal performance of the beam structure.