Assessment of ship manoeuvrability by using a coupling between a nonlinear transient manoeuvring model and mathematical programming techmques

In this paper, a numerical method based on a coupling between a mathematical model of nonlinear transient ship manoeuvring motion in the horizontal plane and Mathematical Programming （MP） techniques is proposed. The aim of the proposed procedure is an efficient estimation of optimal ship hydrodynamic parameters in a dynamic model at the early design stage. The proposed procedure has been validated through turning circle and zigzag manoeuvres based on experimental data of sea trials of the 190 000- dwt oil tanker. Comparisons between experimental and computed data show a good agreement of overall tendency in manoeuvring traiectories.     

CPM-MCHM:一种基于极大团和哈希表的空间并置模式挖掘算法

空间并置(co-location)模式挖掘是指在大量的空间数据中发现一组空间特征的子集,这些特征的实例在地理空间中频繁并置出现.传统的空间并置模式挖掘算法通常采用逐阶递增的挖掘框架,从低阶模式开始生成候选模式并计算其参与度(空间并置模式的频繁性度量指标).虽然这种挖掘框架可以得到正确和完整的结果,但是带来的时间和空间开...     

Effect of fly ash and slag on concrete: Properties and emission analyses

Recycled concrete is a material with the potential to create a sustainable construction industry. However, recycled concrete presents heterogeneous properties, thereby reducing its applications for some structural purposes and enhancing its application in pavements. This paper provides an insight into a solution in the deformation control for recycled concrete by adding supplementary cementitious materials fly ash and blast furnace slag. Results of this study indicated that the 50% fly ash replacement of Portland cement increased the rupture modulus of the recycled concrete. Conversely, a mixture with over 50% cement replacement by either fly ash or slag or a combination of both exhibited detrimental effect on the compressive strength, rupture modulus, and drying shrinkage. The combined analysis of environmental impacts and mechanical properties of recycled concrete demonstrated the possibility of optimizing the selection of recycled concrete because the best scenario in this study was obtained with the concrete mixture M8 (50% of fly ash+ 100% recycled coarse aggregate).     

Anodic Spark Deposition from Aqueous Solutions of NaAlO2 and Na2SiO3

Coatings were deposited on Cu⁰, Ni⁰, and Al⁰ anodes from aqueous solutions of NaAlO₂ and Na₂SiO₃ by anodic spark deposition. Some coatings formed at constant current density (1.0 A/cm²) were characterized by scanning electron microscopy, electron beam microprobe analysis, X-ray diffraction, and emission spectroscopy. A relation for the current decay during a multiple-spark, constant-voltage process was determined. This relation, which describes the behavior of most of the systems studied, is

where φ_t, φ₀, and φ_∞ are the current densities at time t , at the start of the decay ( t =0), and at the steady state, respectively. K is a constant that is voltage and system dependent.     

基于基因表达编程和粒子群优化鲁棒混合计算模型的深部地下矿井岩爆分类

在深部地下采矿中,岩爆因具有许多不利影响（如对人员、设备、隧道/地下矿山工作面和开采周期等的影响）而被视为不确定性风险。由于其不确定性的特征,对岩爆趋势的准确预测和分类具有一定难度,且已有研究成果较少。提出一种基于基因表达编程（GEP）和粒子群优化（PSO）的鲁棒混合计算模型GEP-PSO,用于预测和分类深部开口的岩爆趋势,提高了预测和分类的准确性。在建立GEP-PSO模型的过程中,评估GEP模型中不同数量的基因（1~4）和连接功能（例如,加法、提取、乘法和除法）。收集246次岩爆发生的地质和施工因素,用于建立岩爆分类的GEP-PSO模型;应用处理数据集缺失值的技术改进数据集的属性;用相关矩阵选取潜在输入参数的特征;建立13个混合GEP-PSO模型,得到各模型的精度。结果表明：在GEP结构中具有3个基因和乘法连接函数的GEP-PSO模型具有最高的准确度（80.49%）。将获得的最佳GEP-PSO模型的结果与基于相同数据集开发的各种已有模型进行比较,结果表明,选择的GEP-PSO模型结果优于已有模型,表明提出的GEP-PSO模型在岩爆等级的预测和分类方面的准确性显著提高,可以应用于深开挖工程中,以准确预测和评估岩爆敏感性。     

Polyvinyl alcohol–potassium iodide gel probe to monitor the distribution of reactive species generation around atmospheric-pressure plasma jet

This study proposes polyvinyl alcohol–potassium iodide (PVA–KI) as a novel gel chemical probe. The probe uses the reactions among PVA, KI, water, borax, and oxidative species to visualize the distribution of reactive species. This method provides information regarding the distribution of reactive species by coloration on the gel surface. The effects of the surrounding gas phase on the distribution and diffusion of the reactive species are also investigated using the PVA–KI gel probe. Further, the relationship between the irradiation distance and reactive species diffusion is determined on the surface of the PVA–KI probe with and without plastic shielding. Adjusting the irradiation distance appropriately leads to an increase in the modified area as detected by the PVA–KI gel probe analysis. The relative concentration distributions of the reactive species are also obtained from visualized color distributions measured using a colorimeter. Furthermore, reactive species generation by long-scale line plasma is confirmed by the color reaction on the PVA–KI gel surface, with a greater area being covered by an atmospheric-pressure pulsed microwave line plasma source.