Steel slag waste combined with melamine pyrophosphate as a flame retardant for rigid polyurethane foams

To explore the potential application of industrial waste, steel slag powder in combination with melamine pyrophosphate (MPP) was adopted to improve the flame retardancy of rigid polyurethane foam (RPUF). The incorporation of steel slag slightly reduced the thermal conductivity of the resulting flame-retardant RPUF samples. The addition of MPP and/or steel slag did not significantly alter the thermal stability in terms of T_-10% and T_max but did obviously increase the T_-50% value, suggesting the improved thermal resistance of the residues. The coaddition of MPP and steel slag into RPUF resulted in higher LOI values and lower peak heat release rates than the samples incorporating either MPP or steel slag alone. The superior flame retardancy could be attributed to MPP promoting char formation, which then acted as a barrier at the beginning of RPUF thermal decomposition; simultaneously, the thermally stable inorganics in the steel slag powder strengthened the thermal resistance of this char layer.     

The control of paracetamol particle size and surface morphology through crystallisation in a spray dryer

The parameters governing the crystallisation of paracetamol using various conventional techniques has been extensively studied, however the factors influencing the drug crystallisation using spray drying is not as well understood. The aim of this work was to investigate the crystallisation of an active pharmaceutical ingredient through evaporative crystallisation using a spray dryer to study the physicochemical properties of the drug and to use semi-empirical equations to gain insight into the morphology and particle size of the dried powder. Paracetamol solutions were spray dried at various inlet temperatures ranging from 60 °C to 120 °C and also from a series of inlet feed solvent compositions ranging from 50/50% v/v ethanol/water to 100% ethanol and solid-state characterisation was done. The size and morphology of the dried materials were altered with a change in spray drying parameters, with an increase in inlet temperature leading to an increase in particle Sauter mean diameter (from 3.0 to 4.4 µm) and a decrease in the particle size with an increase in ethanol concentration in the feed (from 4.6 to 4.4 µm) as a result of changes in particle density and atomised droplet size. The morphology of the dried particles consisted of agglomerates of individual crystallites bound together into larger semi-spherical agglomerates with a higher tendency for particles having crystalline ridges to form at higher ethanol concentrations of the feed.     

Quantitative relationship between time margin and human reliability

Operator reliability in complex systems is influenced by various performance shaping factors (PSFs). Time is a particularly important PSF; however, empirical studies of human reliability analysis (HRA) are rarely focused on modeling the effect of time PSF on human error probability (HEP). This study contributes to HRA literature by investigating the empirical relationship between time margin and HEP. Time margin is defined as the difference between the time available to complete a task and the time required to successfully complete the task, divided by the required time. We investigate and compare two models (logistic and linear) to explain HEP based on time margin. The empirical HEP data for model testing were extracted from a microworld simulator (Study 1) and a full-scope simulator (Study 2) in two existing studies relevant to procedural tasks in nuclear power plants. For Study 1, both models exhibited an acceptable, equivalent explanatory power; for Study 2, although both models exhibited an acceptable explanatory ability, the logistic model explained more variance in HEP. Our findings indicate the potential of the logistic model in explaining and predicting HEP based on time margin in time-critical tasks.     

冷挤压对高合金化7000系铝合金抗腐蚀性能的影响

研究了经固溶-时效和固溶-冷挤压-时效处理的高合金化Al-12.3Zn-3Mg-2.5Cu-0.18Zr-0.07Sr铝合金的微观组织与抗腐蚀性能。结果表明:固溶-时效和固溶-冷挤压-时效状态下高合金化铝合金的晶粒都呈现明显的带状分布,但固溶-冷挤压-时效状态下合金内部亚晶比例明显上升;相比固溶-时效,固溶-冷挤压-时效状态下高合金化铝合金的抗腐蚀性能(剥落腐蚀和晶间腐蚀)有明显的提高,可见冷挤压变形是提高7000系铝合金腐蚀性能的有效手段。     

三菱Q系列PLC串口自由通讯方法的探究

多种工业控制场合需要使用智能设备,并以串行通信将数据发送至上位机。三菱Q系列PLC无顺序通信方法仅支持接收“固定长度”与“变长度有固定结尾”两种数据对象,与发送“变长度无固定结尾”数据的智能设备不能妥善匹配。为此设计了一种Q系列PLC串口自由通信方法,该方法采用顺序控制程序实现了“变长度无固定结尾”数据接收、异常数据消除与通信模块故障自恢复,具有破除通信模块设定局限、可自行定义通信协议的特点。经实验其可同时支持多种智能设备,具有良好的适应性和通用性。     

热稳定处理时间对TNM合金糊状区组织的影响

利用真空非自耗电弧炉制备了TNM(Ti-44Al-4Nb-1Mo-0.1B at.%)合金锭,研究其铸态组织形貌,并利用Bridgeman定向凝固装置对TNM合金进行热稳定处理实验,分析热稳定处理时间对合金定向凝固糊状区的影响。实验结果显示,其铸态组织是以(α₂+γ)片层团为主体,网络状B2相、细小的γ相及硼化物分布于片层团间的近片层组织。热稳定处理时,热稳定时间越长、TNM合金固/液界面越平整,界面前沿温度场和溶质场趋向均匀,但从减少坩埚对熔体的污染的角度考虑,热稳定处理时间不宜过长,30~60 min的热稳定时间即可提供平整的定向凝固启动界面。 热稳定处理影响着TNM合金固/液界面附近固液两相中Al元素的分布,进而影响硼化物的分布。     

基于ARIMA时间序列模型的中国塑料制品产量预测研究

根据中国2000~2019年塑料制品产量的时间序列数据,研究差分自回归移动平均模型ARIMA(p,d,q)的建模和应用。利用白噪声检验和平稳性检验对原始序列进行预处理及ARIMA模型识别,在模型定阶后进行参数估计,检验模型拟合效果,并预测塑料制品的产量。结果表明:ARIMA(2,1,1)模型可以很好地描述塑料制品产量的变化趋势,使用该模型可以预测未来五年的塑料制品产量。     

A mechanism informed neural network for predicting machining deformation of annular parts

Controlling machining deformation of annular parts is crucial for ensuring the performance of high value products and equipment. For example, during manufacturing of critical parts in aircrafts and spacecrafts, accurate prediction of machining deformation is the basis for guiding the formulation of deformation control strategies. However, due to the complexity of the machining deformation of annular parts, existing methods still have limitations in accurate prediction. To this end, this paper proposes a mechanism informed neural network (MINN) to predict machining deformation of annular parts. MINN is realized by establishing the dual sub-networks structure and using enhanced loss functions with the consideration of the deformation mechanism model characteristics of annular parts. The deformation was decomposed into the axisymmetric portion and the non-axisymmetric portion according to the deformation superposition principle, and modeled separately based on the thin-shell theory and Fourier series. Experiment results showed that the proposed method could predict the machining deformation of annular parts more accurately and stably with a small amount of training data, compared with previous methods.     

基于时序数据的云网协同平台人工智能运维体系

云计算在企业应用中的拓展不但表现为平台规模的拓展，也表现为平台应用的延伸。“云网协同”和“微服务化”是当前企业云平台演进的重要趋势。随着企业信息化建设重要性的持续提升，微服务化云网协同平台的运行维护面临极大挑战。首先分析了平台运维面临的挑战，梳理了平台人工智能运维需求，提出了基于时序数据分析的平台人工智能运维技术体系，并给出了云网协同平台人工智能运维子系统参考设计。所提技术体系和系统设计具有实用性和推广性，可以作为企业云平台建设和优化的技术途径参考。     

基于CPET时序聚类的中长跑耐力运动员选拔方法

心肺运动试验（CPET）能将人体的呼吸系统、心血管系统等综合为一体，不仅能够体现受试者的有氧运动能力，评估受试者的心肺耐力，而且能以整体整合医学的视角来研究受试者对运动的应激反应。为对CPET数据进行凝聚层次聚类分析，提出一种基于时间序列形态特征的算法。选取15名业余中长跑运动员的CPET数据作为聚类对象，聚类指标选取了表征有氧能力和心肺耐量的耗氧量、二氧化碳、心率、分钟通气当量、代谢当量、生理死腔与潮气量比值、呼吸商及每搏输出量等8类指标，体现运动员摄取、利用氧的效率、肺循环以及心功能等综合状况。通过聚类分析发现受试者个体差异较大，未出现明显的“群居分布”特征，根据轮廓系数评估可剔除心肺耐量较差的测试者。实验结果表明，该算法在确保聚类准确率的同时能够降低数据压缩率，且对形态特征显著的数据集进行聚类效果更佳。