Conditions of Liquid Steel Treatment for Near Net‐Shape Casting Processes

Slab casting for hot rolled steel and strip casting using the twin roll casting (TRC) method are compared in terms of inclusions evolution. There are differences of the processes, mainly the use of casting flux in CC of slabs, or pool shapes and sizes in terms of TRC, particularly when roll diameters vary. The inclusion evolution of alumina in a low carbon steel grade was estimated. By modelling particle growth rate, coagulation and deposition, an ‘agglomeration index’ was created to describe the probability of clogging in the SEN. Similarly the growth of secondary alumina precipitation during cooling of the melt in the pool by Stokes collision and turbulent collision was estimated in terms of forming large particles which are able to float‐up. Influences of melt superheat or caster size were taken into account.     

Modern Teaching and Training in Metallurgical Engineering

This contribution deals with advanced educational technologies needed to equip customers from higher education institutions, research and industry with efficient tools supporting their work and operating new skills‐training methods. The challenges are reducing the training costs, improving quality and increasing the number of graduates in engineering departments. The concept of a Virtual Lab based on the combination of various teaching methods and tools is presented. Principles of mathematisation in metallurgical education and training are discussed. An example of online course designed in the form of Virtual Lab is demonstrated.     

Algorithms for processing the group K nearest-neighbor query on distributed frameworks

Distributed and Parallel Databases - Given two datasets of points (called Query and Training), the Group (K) Nearest-Neighbor (GKNN) query retrieves (K) points of the Training with the smallest sum...     

Testing and applications of a process model in the metallurgical production practice of ferronickel from laterites

A mathematical model of the electro-reduction furnace process (ERF process), for the production of ferronickel from laterite ores, has been tested at Larco's metallurgical plant at Larymna Greece. The theoretical predictions for the progress of the nickel reduction have been compared with the operational results. The tests were carried out in the ERF no. 2 of Larco's plant. The influence of the main process variables on the nickel recovery and nickel losses in the ERF slags have been investigated in conjunction with the variation of the analysis of the feed and the nickel content of the metal bath. The further application of the model to the metallurgical practice is discussed. According to the predictions of the model the further development of the process in the direction of the production of low-nickel ferronickel (Ni < 15%) is analyzed. The advantages of the production of low-nickel ferronickel are presented and the possibility of its straight conversion to nickel-bearing steel-grades is discussed.     

Classification of atherosclerotic carotid plaques using morphological analysis on ultrasound images

The aim of this study was to investigate the usefulness of multilevel binary and gray scale morphological analysis in the assessment of atherosclerotic carotid plaques. Ultrasound images were recorded from 137 asymptomatic and 137 symptomatic plaques (Stroke, Transient Ischaemic Attack (TIA), Amaurosis Fugax (AF)). We carefully develop the clinical motivation behind our approach. We do this by relating the proposed L-images, M-images and H-images in terms of the clinically established hypoechoic, isoechoic and hyperechoic classification. Normalized pattern spectra were computed for both a structural, multilevel binary morphological model, and a direct gray scale morphology model. From the plots of the average pattern spectra, it is clear that we have significant differences between the symptomatic and asymptomatic spectra. Here, we note that the morphological measurements appear to be in agreement with the clinical assertion that symptomatic plaques tend to have large lipid cores while the asymptomatic plaques tend to have small lipid cores. The derived pattern spectra were used as classification features with two different classifiers, the Probabilistic Neural Network (PNN) and the Support Vector Machine (SVM). Both classifiers were used for classifying the pattern spectra into either a symptomatic or an asymptomatic class. The highest percentage of correct classifications score was 73.7% for multilevel binary morphological image analysis and 66.8% for gray scale morphological analysis. Both were achieved using the SVM classifier. Among all features, the L-image pattern spectra, that also measure the distributions of the lipid core components (and some non-lipid components) gave the best classification results.     

Process metallurgical evaluation and application of very fine bubbling technology

The potential of VFB(v ery f ine b ubbling)‐technology in steelmaking, developed for the production of super clean steels, was investigated. Recent R&D work has proven that with very fine argon bubbling through a developed special porous plug (SPP) at low flow rates, the total oxygen content of low carbon steel grades can be lowered to a level of 6 ppm under industrial vacuum conditions [1; 2] and to a level of 10 ppm under argon protective atmosphere [2]. The perspective of industrial application of the VFB technology to a 56‐t ladle furnace of Helliniki Halyvourgia S.A., Greece, in order to improve steel cleanliness, requires additional R&D efforts. It is important to define the limits of VFB technology in respect of alloys dissolution, mixing time and homogenisation of steel and slag/metal reactions. In this work, a gas driven bubble aqueous reactor model simulating the bottom gas stirred ladle by means of gas injection through a SPP and a conventional porous plug was studied. Various operating conditions as well as different positions for the porous plug with and without a top oil layer were simulated. Tests concerning mixing time, solid‐liquid mass transfer and critical gas flow rate, liquid/liquid mass transfer, using the SPP and a conventional porous plug have been performed. The evaluation of experimental results delivered important information for the design and operation of steel ladles, applying VFB‐technology. Experimental results with SPP bubbles’ agitated steel (1600 °C) in laboratory and technical scale experiments in IF and VIF are presented and discussed.     

The Effect of Nutrient Fortification of Sauces on Product Stability,Sensory Properties,and Subsequent Liking by Older Adults

There are potential nutritional and sensory benefits of adding sauces to hospital meals. The aim of this study was to develop nutrient fortified sauces with acceptable sensory properties suitable for older people at risk of undernutrition. Tomato, gravy, and white sauce were fortified with macro‐ and micronutrients using food ingredients rich in energy and protein as well as vitamin and mineral premixes. Sensory profile was assessed by a trained panel. Hedonic liking of fortified compared with standard sauces was evaluated by healthy older volunteers. The fortified sauces had higher nutritional value than the conventional ones, for example the energy content of the fortified tomato, white sauce, and gravy formulations were increased between 2.5‐ and 4‐fold compared to their control formulations. Healthy older consumers preferred the fortified tomato sauce compared with unfortified. There were no significant differences in liking between the fortified and standard option for gravy. There were limitations in the extent of fortification with protein, potassium, and magnesium, as excessive inclusion resulted in bitterness, undesired flavors, or textural issues. This was particularly marked in the white sauce to the extent that their sensory characteristics were not sufficiently optimized for hedonic testing. It is proposed that the development of fortified sauces is a simple approach to improving energy intake for hospitalized older people, both through the nutrient composition of the sauce itself and due to the benefits of increasing sensorial taste and lubrication in the mouth.     

刚性淹没球冠状植被水流特性试验研究

本文将植被体型概化为由球状树冠和主干组成的树状植被,采用Micro ADV测量了树状植被影响下明渠水流的流速分布,分析了不同流量和水深条件下4组树状植被对明渠水流的影响,着重研究了树状刚性植被水流的平均流动和紊动结构,比较了多个典型位置处水流的纵向流速、垂向流速以及紊动强度。试验结果表明,水深越小,无量纲纵向流速越大;树冠的形状对水流特性的影响较大,在树状植被附近,纵向流速的垂向分布在树干层近似均匀分布,在树冠层先减小后增大,在无植被层符合对数分布;紊动强度在树冠层较大,在树干层和无植被层较小;通过象限分析,发现下扫作用主要在植被层起主导作用,喷射作用主要在自由水层占主导。