On Some Ev-Degree and Ve-Degree Dependent Indices of Benes Network and Its Derived Classes

One of the most recent developments in the field of graph theory is the analysis of networks such as Butterfly networks,Benes networks,Interconnection networks,and David-derived networks using graph theoretic parameters.The topological indices(TIs)have been widely used as graph invariants among various graph theoretic tools.Quantitative structure activity relationships(QSAR)and quantitative structure property relationships(QSPR)need the use of TIs.Different structure-based parameters,such as the degree and distance of vertices in graphs,contribute to the determination of the values of TIs.Among other recently introduced novelties,the classes of ev-degree and ve-degree dependent TIs have been extensively explored for various graph families.The current research focuses on the development of formulae for different ev-degree and ve-degree dependent TIs for s−dimensional Benes network and certain networks derived from it.In the end,a comparison between the values of the TIs for these networks has been presented through graphical tools.

Numerical study of the influence of spoiler deflection on high-lift configuration

This paper numerically studies the influence of the downward spoiler deflection on the boundary layer flow of a high-lift two-element airfoil consisting of a droop nose, a main wing, a downward deflecting spoiler and a single slotted flap. Both of the boundary layer of the upper surface of the spoiler and the confluent boundary layer of the upper surface of the flap become thicker, as the downward spoiler deflection increases. Compared to the attached flow at the angle of attack of 10°, the flow of the upper surface of the spoiler becomes separated at the angle of attack of 16° when the spoiler deflection is large enough, which corresponds to the boundary layer flow reversal in velocity profiles.

Evaluation of ICUs and weight of quality control indicators:an exploratory study based on Chinese ICU quality data from 2015 to 2020

This study aimed to explore key quality control factors that affected the prognosis of intensive care unit(ICU)patients in Chinese mainland over six years(2015–2020).The data for this study were from 31 provincial and municipal hospitals(3425 hospital ICUs)and included 2110685 ICU patients,for a total of 27607376 ICU hospitalization days.We found that 15 initially established quality control indicators were good predictors of patient prognosis,including percentage of ICU patients out of all inpatients(%),percentage of ICU bed occupancy of total inpatient bed occupancy(%),percentage of all ICU inpatients with an APACHE II score≥15(%),three-hour(surviving sepsis campaign)SSC bundle compliance(%),six-hour SSC bundle compliance(%),rate of microbe detection before antibiotics(%),percentage of drug deep venous thrombosis(DVT)prophylaxis(%),percentage of unplanned endotracheal extubations(%),percentage of patients reintubated within 48 hours(%),unplanned transfers to the ICU(%),48-h ICU readmission rate(%),ventilator associated pneumonia(VAP)(per 1000 ventilator days),catheter related blood stream infection(CRBSI)(per 1000 catheter days),catheter-associated urinary tract infections(CAUTI)(per 1000 catheter days),in-hospital mortality(%).When exploratory factor analysis was applied,the 15 indicators were divided into 6 core elements that varied in weight regarding quality evaluation:nosocomial infection management(21.35%),compliance with the Surviving Sepsis Campaign guidelines(17.97%),ICU resources(17.46%),airway management(15.53%),prevention of deep-vein thrombosis(14.07%),and severity of patient condition(13.61%).Based on the different weights of the core elements associated with the 15 indicators,we developed an integrated quality scoring system defined as F score=21.35%xnosocomial infection management+17.97%xcompliance with SSC guidelines+17.46%×ICU resources+15.53%×airway management+14.07%×DVT prevention+13.61%×severity of patient condition.This evidence-based quality scoring system will help in assessing the key elements of quality management and establish a foundation for further optimization of the quality control indicator system.

Defect suppression mechanism of ultrasonic vibration-assisted drilling carbon fiber/bismaleimide composite

Ultrasonic vibration-assisted drilling(UVAD)has recently been successfully applied in the drilling of carbon fiber reinforced polymer/plastic(CFRP)due to its high reliability.Multiple defects have been observed in the CFRP drilling process which negatively affects the quality of the hole.The carbon fiber/bismaleimide(BMI)composites is an advanced kind of CFRPs with greater strength and heat resistance,having been rapidly applied in lightweight and high temperature resistant structures in the aerospace field.To suppress the defect during the drilling of carbon fiber/BMI composites,it is necessary to comprehensively understand the defect formation and suppression mechanism at different positions.In this study,the defects formation in both conventional drilling(CD)and UVAD were observed and analyzed.The variation trend in the defect factor and thrust force with the spindle speed and feed rate were acquired.The results revealed that the UVAD could significantly enhance the hole’s quality with no delamination and burr.Meanwhile,the defect suppression mechanism and thrust force in UVAD were analyzed and verified,where the method of rod chip removal affected the exit defect formation.In summary,UVAD can be considered a promising and competitive technique for drilling carbon fiber/BMI composites.

Effect of creep feed grinding on surface integrity and fatigue life of Ni3Al based superalloy IC10

Ni3Al-based superalloy IC10 is widely used in high temperature components of aeroengines because of its superior mechanical properties.In this paper,the creep feed grinding properties of IC10 were investigated experimentally.The effects of grinding parameters on the grinding forces and temperature were examined.Moreover,the influences of surface roughness and hardening on the high-cycle fatigue life of IC10 specimens were studied.To control the creep feed grinding parameters and enhance the fatigue life of IC10 components,the experimental results were summarized to offer a useful reference point.It is concluded that,the grinding depth is the most important factor which influencing the grinding forces and temperature;the surface roughness is the main and unfavorable factor on the fatigue life of IC10,while the surface hardening has a positive influence on the fatigue life;to obtain a better surface quality and improve the fatigue life of IC 10,the recommended grinding parameter domain involves wheel speed 2[15,20]m/s,feed rate∈[150,200]mm/min,and grinding depth∈[0.4,0.5]mm.

Investigation on surface roughness,residual stress and fatigue property of milling in-situ TiB_2/7050Al metal matrix composites

For higher efficiency and precision manufacturing,more and more attentions are focused on the surface roughness and residual stress of machined parts to obtain a good fatigue life.At present,the in-situ TiB_2/7050 Al metal matrix composites are widely researched due to its attractive properties such as low density,good wear resistance and improved strength.It is of great significance to investigate the machined surface roughness,residual stress and fatigue life for higher efficiency and precision manufacturing of this new kind material.In this study,the surface roughness including two-dimensional and three-dimensional roughness,residual stress and fatigue life of milling in-situ TiB_2/7050 Al metal matrix composites were analyzed.It was found from comparative investigation that the three-dimensional surface roughness would be more appropriate to represent the machined surface profile of milling particle reinforced metal matrix composites.The cutting temperature played a great role on the residual stress.However,the effect of increasing cutting force could slow down the transformation from compressive stress to tensile stress under 270°C.An exponential relationship between three-dimensional roughness and fatigue life was established and the main fracture mechanism was brittle fracture with observation of obvious shellfish veins,river pattern veins and wave shaped veins in fracture surface.

Influence of TiB2 particles on machinability and machining parameter optimization of TiB2/Al MMCs

In situ formed TiB2 particle reinforced aluminum matrix composites （TiB2/Al MMCs） have some extraordinary properties which make them be a promising material for high performance aero-engine blade. Due to the influence of TiB2 particles, the machinability is still a problem which restricts the application of TiB2/Al MMCs. In order to meet the industrial requirements, the influence of TiB2 particles on the machinability of TiB2/Al MMCs was investigated experimentally. Moreover, the optimal machining conditions for this kind of MMCs were investigated in this study. The major conclusions are： （1） the machining force of TiB2/Al MMCs is bigger than that of non- reinforced alloy and mainly controlled by feed rate; （2） the residual stress of TiB2/AI MMCs is compressive while that of non-reinforced alloy is nearly neutral; （3） the surface roughness of TiB2/Al MMCs is smaller than that of non-reinforced alloy under the same cutting speed, but reverse result was observed when the feed rate increased; （4） a multi-objective optimization model for surface roughness and material removal rate （MRR） was established, and a set of optimal parameter combinations of the machining was obtained. The results show a great difference from SiC particle reinforced MMCs and provide a useful guide for a better control of machining process of this material.

A wall-thickness compensation strategy for wax pattern of hollow turbine blade

As an important index affecting the aerodynamic performance and the structural strength of hollow turbine blades, the wall-thickness precision of the blade is mainly inherited from the positional relationship between the corresponding wax pattern and the internal ceramic core.However, due to locating errors, the actual position of ceramic core is always deviated from the ideal position, which makes it difficult to guarantee the wall-thickness precision of the wax pattern.To solve this problem, a wall-thickness compensation strategy is proposed in this paper. Firstly,based on the industrial computed tomography(ICT) technique and curve matching algorithms, a model reconstruction method is developed, with which the 3D model of a trial wax pattern can be easily constructed. After that, focusing on eliminating the wall-thickness errors of the trial wax pattern, an optimization method for the pose of the ceramic core in the wax pattern is proposed. Then, by mapping the optimal pose of the ceramic core to length adjustments of the locating rods, the wall-thickness errors of the wax pattern can be greatly reduced. A case study is also given to illustrate the effectiveness of the proposed compensation strategy.

Analytical model of cutting force in axial ultrasonic vibration-assisted milling in-situ TiB_(2)/7050Al PRMMCs

Ultrasonic vibration-assisted milling has been widely applied in machining the difficultto-cut materials owing to the remarkable improvements in reducing the cutting force.However,analytical models to reveal the mechanism and predict the cutting force of ultrasonic vibrationassisted milling metal matrix composites are still needed to be developed.In this paper,an analytical model of cutting force was established for ultrasonic vibration-assisted milling in-situ TiB_(2)/7050 Al metal matrix composites.During modeling,change of motion of the cutting tool,contact of toolchip-workpiece and acceleration of the chip caused by ultrasonic vibration was considered based on equivalent oblique cutting model.Meanwhile,material properties,tool geometry,cutting parameters and vibration parameters were taken into consideration.Furthermore,the developed analytical force model was validated with and without ultrasonic vibration milling experiments on in-situ TiB_(2)/7050 Al metal matrix composites.The predicted cutting forces show to be consistent well with the measured cutting forces.Besides,the relative error of instantaneous maximum forces between the predicted and measured data is from 0.4%to 15.1%.The analytical model is significant for cutting force prediction not only in ultrasonic-vibration assisted milling but also in conventional milling in-situ TiB_(2)/7050 Al metal matrix composites,which was proved with general applicability.

资源型企业跨区转移溢出效应与胁迫效应的比较测度和启示

资源型企业的跨区转移是一个新兴的管理实践问题,对其可能产生的溢出效应与胁迫效应的比较分析和科学测度,是区域高质量发展战略决策的关键。基于系统工程的思想,分析了资源型企业跨区转移溢出效应与胁迫效应的形成机理,提出了“生态溢出效率”的概念与测度指标体系,运用DEA数据包络分析与非参数Malmquist指数相结合的方法,并选取中西部10省份资源型企业2007~2017年相关数据进行实证检验。研究表明:(1)东部省份资源型企业的跨区转移既产生了溢出效应,也形成了胁迫效应。(2)生态溢出效率能够有效测度资源型企业跨区转移溢出效应与胁迫效应的比较关系。(3)生态溢出效率可以分解为纯技术生态溢出效率和规模生态溢出效率,而且纯技术生态溢出效率整体上高于规模生态溢出效率。(4)生态溢出效率偏低的主要致因,依其投入冗余程度由高到低排序为废气排放量、固体废物排放量、土地压占沉陷破坏量和废水排放量。(5)西部省份的生态溢出效率低于中部省份,但其生态溢出效率的增长率高于中部省份。研究结论可为中西部省份资源产业可持续、高质量发展的相关政策制订提供理论依据。