Flow,Thermal and Microstructural Analysis during Cast Rolling of Steel in In‐line Strip Production Process

A mathematical model was developed to describe the in‐line hot rolling deformation and recrystallization behaviour of austenite after the solidification on a thin slab casting plant. The most significant features of the cast rolling process were taken into consideration: through‐thickness thermal gradients, inhomogeneous stress and strain, temperature discontinuity between the strip and the rolls. A HSLA (High Strength Low Alloy) steel has been chosen to perform the experiments of cast rolling. The characteristic constants ruling the microstructural evolution of that steel were computed and integrated into the computational module which manages the structural stress‐strain and strain rate computation. The developed approach is based on the Navier‐Stokes’ equations which were used to compute the speed field in the strip during the deformation. Then a model providing a proper constitutive equation was structured on the basis of the Yada's model based on evolution of the dislocation populations. The use of the Navier‐Stokes’ formalism allows to reach the resolution of the structural problem from the data measured easily during the industrial practice (i.e. speed of the rolled product at the entry and at the exit of a stand, the temperature of the rolled material). The validation of this computational approach was obtained by a comparison between the prior austenite grain size of the strip in different positions of the hot rolling process, as well as by a comparison between the computed deformation power and the measured one provided by the engines moving the rolls.     

Comparison between symmetric and asymmetric hot rolling techniques performed on duplex stainless steel 2205

The use of duplex stainless steel represents one possible efficient alternative of austenitic grade and an interesting resources for its high performance against stress corrosion cracking. Unfortunately such material shows some limitations in their use: for instance the sheets or plates of duplex stainless steels present anomalous and poor formability for plastic deformation processes. Such problems are mainly related to an unsuitable normal anisotropy coefficient, which might cause the “necking” and “earing” phenomena, especially during hot rolling. The study deals with the comparison of symmetric and asymmetric rolling technique on stainless steel duplex 2205 specimens. All the experiments were carried out using a laboratory mill, properly equipped with an individual engine for each rolling cylinder. The experimental parameters considered include three different pre-heating temperatures and two asymmetry ratios, while the reduction level is maintained constant for both rolling configurations. Moreover, the study involves also the analysis of the influence of solubilization quenching and the SEM, SEM-EBSD investigation dedicated to establish the microstructure modifications. The specimens were also studied through tensile tests to determine the influence of the rolling techniques on the mechanical properties of the product, focusing on the definition of the average anisotropy coefficient. The results of the experimental trials allow to conclude that the use of asymmetric rolling process induces an improved formability and increases duplex 2205 tensile properties.     

A solidification model for prediction of castability in the precipitation-strengthened nickel-based superalloys

The Scheil equation was used to model the solidification path, microsegregation of alloying elements in the interdendritic regions, solidification temperature ranges, and to predict the formation of secondary structures and the castability behavior of as-cast superalloys. 4 experimental alloys with pre-specified γ-Ti,Nb,Al,Mo composition containing different Nb, Ti and Al contents were designed using vacuum induction melting furnace. The produced as-cast superalloys were characterized using optical and scanning electron microscopy equipped with energy dispersive X-ray spectrometer and TG–DSC analysis. The experiments showed logic conformity to the modeling results. The model and experiment confirmed the highest segregation behavior for Ti and Nb. All the experimental superalloys indicated the remarkable tendency to form secondary eutectic structures at the last stages of solidification. Superalloy with chemical composition of γ-3.5%Mo,1.8%Al,4%Ti,2.9%Nb showed the shorter solidification temperature range and the best castability.     

Plug-In Hybrid Electric Vehicle: Modeling, Prototype Realization, and Inverter Losses Reduction Analysis

Nowadays, the greatest part of the effort to reduce pollution emissions is directed toward the hybridization of automotive drive trains. In particular, the design of hybrid vehicles requires a complete system analysis, including the optimization of the electric and electronic devices installed on the vehicle and the design of all the mechanical connections between the different power sources to reach the required performances. The aim of this paper is to describe the design and prototype realization of a plug-in hybrid electrical vehicle (PHEV). Specifically, an energetic model was developed in order to analyze and optimize the power flux between the different parts. This model was experimentally validated using a prototype PHEV. In addition, in order to improve the driving range in an all-electric model (all-electric range), a detailed analysis of the inverter control was performed, because this component is one of the key components of the power train. In order to reduce inverter losses and dimensions, several control methods can be adopted. In this paper, a direct self-control strategy for reducing the inverter losses is presented and validated.      

Discovery of New Antiproliferative Imidazopyrazole Acylhydrazones Able To Interact with Microtubule Systems

Even though immunotherapy has radically changed the search for anticancer therapies, there are still many different pathways that are open to intervention with traditional small molecules. To expand our investigation in the anticancer field, we report here a new series of compounds in which our previous pyrazole and imidazopyrazole scaffolds are linked to a differently decorated phenyl ring through an acylhydrazone linker. Preliminary tests on the library were performed at the National Cancer Institute (USA) against the full NCI 60 cell panel. The best compounds among the imidazopyrazole series were then tested by immunofluorescence staining for their inhibition of cell proliferation, apoptosis induction, and their effect on the cell cycle and on microtubules. Two compounds, in particular 4-benzyloxy-3-methoxybenzyliden imidazopyrazole-7-carbohydrazide showed good growth inhibition, with IC₅₀ values in the low-micromolar range, and induced apoptosis. Both compounds altered the cell-cycle phases with the appearance of polyploid cells. Immunofluorescence analysis evidenced microtubules alterations; tubulin polymerization assays and docking studies suggested the tubulin system to be the possible, although not exclusive, target of the new acylhydrazone series reported here.     

Modeling Neurotransmission: Computational Tools to Investigate Neurological Disorders

The investigation of synaptic functions remains one of the most fascinating challenges in the field of neuroscience and a large number of experimental methods have been tuned to dissect the mechanisms taking part in the neurotransmission process. Furthermore, the understanding of the insights of neurological disorders originating from alterations in neurotransmission often requires the development of (i) animal models of pathologies, (ii) invasive tools and (iii) targeted pharmacological approaches. In the last decades, additional tools to explore neurological diseases have been provided to the scientific community. A wide range of computational models in fact have been developed to explore the alterations of the mechanisms involved in neurotransmission following the emergence of neurological pathologies. Here, we review some of the advancements in the development of computational methods employed to investigate neuronal circuits with a particular focus on the application to the most diffuse neurological disorders.     

电弧炉炉渣的显微结构和化学特性

炉渣材料代替水泥是一个很好的选择。特别是电弧炉（EAF）熔融过程中产生的炉渣，可作为填埋道路场地和生产混凝土的材料。但是炉渣中含有污染性的化学元素，如铬、钡、钒、钼等，使其应用受到限制。本文对两个生产钢筋的意大利炼钢厂的炉渣进行了测试。结果表明，炉渣的化学成分在一个范围内，且在此范围内炉渣显示了一个释放行为；基本组分（如CaO、SiO2、Al2O3、MgO等）的比例对炉渣的释放行为有着显著影响。采用光学碱度法表征了材料的化学成分；并采用扫描电子显微镜研究了炉渣的显微结构，确认了炉渣中存在的主要物相、化学成分和溶解在每一物相中的污染元素。对化学分析、显微结构分析和释放性试验结果进行综合分析，确定了具体的化学成分范围来预防危险的化学释放，这种分析方法为确定正确处理炉渣的程序具有重要的指导意义。