Mathematical Modeling of the Mold Current and Its Influence on Slag and Ingot Behavior during ESR

2015 ◽  
Vol 15 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Mathilde Hugo ◽  
Alain Jardy ◽  
Bernard Dussoubs ◽  
Jessica Escaffre ◽  
Henri Poisson

AbstractElectroSlag Remelting (ESR) is widely used to produce high added value alloys for critical applications (aerospace industry, nuclear plants, etc.). In collaboration with Aubert & Duval, Institut Jean Lamour has been developing for several years a numerical transient model of an ESR heat. In the previous version of the model, the crucible was assumed to be perfectly electrically insulated from the electrode-slag-ingot system. However, this assumption must be challenged: the solidified slag skin at the slag/mold and ingot/mold interfaces may actually allow a fraction of the melting current to reach the crucible. In this paper, an evolution of the model is presented that enabled us to take into account the possibility of mold current. The simulation results were compared with actual experimental data. Sensitivity studies showed the influence of slag properties and operating parameters on the final quality of the ingot. Results highlighted that even a weakly conductive solidified slag skin at the inner surface of the model can be responsible for a non-negligible amount of current circulating between the slag and crucible, which modifies the fluid flow, heat transfer and solidification of both the slag phase and the metallic ingot.

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Samavedam Santhi ◽  
S. B. Sakri ◽  
Dharwada Hanumantha Rao ◽  
Srinivasan Sundarrajan

Mould filling ability characteristic has been influencing the liquid metal flow, heat transfer, and solidification there by affecting the quality of aerospace castings. Mould filling is a critical parameter in the production of sound and quality castings, especially in the case of complex-shaped castings where section thickness is varying considerably. The mould filling ability of aluminium alloys LM6 and LM25 has been studied in the present investigation. Experimentation has been carried out using orthogonal array experimental layout. The process parameters studied in the present investigation are alloy composition, sand fineness, mould coating, and pouring temperature. The mould filling ability of selected aluminium alloy has been studied using pin test piece with cylindrical cores. The results from experimentation are analyzed to find the influence of the process parameters on mould filling ability. Based on the above, LM6 alloy has been found to have better mould filling ability characteristics and the analysis of variance has also revealed the same optimum factor combination.


Author(s):  
Ianto Martins ◽  
Arthur Pandolfo da Veiga ◽  
Eduardo Alves ◽  
Jader Barbosa

Land ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 724
Author(s):  
Alicja K. Zawadzka

The paper presents the results of a study on the attractiveness to tourists and natives of the cultural qualities of coastal towns on The Pomeranian Way of St. James that are members of the Cittaslow network. Attention to the quality of urban life is inscribed in the development policies of towns applying to join the Cittaslow movement. In order to join the network (apart from the size criterion), towns need to meet a minimum of 50% plus one of the 72 criteria grouped into seven categories. One of the category is Quality of Urban Life Policy, so the towns applying to join Cittaslow commit themselves to actions aimed at improving the quality of urban life. The study on the attractiveness of cultural qualities of towns to tourists and natives was conducted using the author’s BRB method, whose added value is its universality and the possibility to study small towns regardless of their membership in the Cittaslow network. BRB is an acronym that stands for BUILDINGS, RELATIONSHIPS, BALANCE, and comprises three scopes of activities: BUILDINGS (iconic building and important sites where the inhabitants and the tourists are present); RELATIONSHIPS (the visual effects of the relations between the inhabitants and the town) and BALANCE (solutions that implement modern technologies). This method enables identification of places that are important to the inhabitants, where urban life takes place and which are often created with the involvement of the inhabitants. These are often the same spaces as those that attract tourists and perhaps stimulate them the desire to visit the town again (BRB—be right back). The aim of the BRB method is shown the attractiveness of small towns. The study has shown that the characteristic feature of Polish Cittaslow towns is their diversity: the architectural attractiveness of three towns is high both to tourists and natives. On the other hand, the urban attractiveness of the examined towns is an insufficient.


BMJ Open ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. e039517
Author(s):  
Gaurav Jyani ◽  
Shankar Prinja ◽  
Sitanshu Sekhar Kar ◽  
Mayur Trivedi ◽  
Binod Patro ◽  
...  

IntroductionQuality-adjusted life year (QALY) has been recommended by the government as preferred outcome measure for Health Technology Assessment (HTA) in India. As country-specific health-related quality of life tariff values are essential for accurate measurement of QALYs, the government of India has commissioned the present study. The aim of this paper is to describe the methods for the Development of an EQ-5D Value set for India using an Extended design (DEVINE) Study. Additionally, this study aspires to establish if the design of 10-time trade-off (TTO) blocks is enough to generate valid value sets.Methods and analysisA cross-sectional survey using the EuroQol Group’s Valuation Technology (EQ-VT) will be undertaken in a sample of 2700 respondents selected from six different states of India using a multistage stratified random sampling technique. The participants will be interviewed using computer-assisted personal interviewing technique. The TTO valuation will be done using 10 composite TTO (c-TTO) tasks and 7 discrete choice experiment (DCE) tasks. Hybrid modelling approach using both c-TTO and DCE data to estimate the potential value set will be applied. Values of all 3125 health states will be predicted using both the conventional EQ-VT design of 10 blocks of 10 TTO tasks, and an extended design of 18 blocks of 10 TTO tasks. The potential added value of the eight additional blocks in overall validity will be tested. The study will deliver value set for India and assess the adequacy of existing 10-blocks design to be able to correctly predict the values of all 3125 health states.Ethics and disseminationThe ethical approval has been obtained from Institutional Ethics Committee of PGIMER, Chandigarh, India. The anonymised EQ-5D-5L value set will be available for general use and in the HTAs commissioned by India’s central HTA Agency.


2017 ◽  
Vol 45 (12) ◽  
pp. 1298-1316 ◽  
Author(s):  
Magali Jara ◽  
Gérard Cliquet ◽  
Isabelle Robert

Purpose The purpose of this paper is to tackle the issue of store brand equity by considering two store brand’s positioning strategies: those with high perceived added value (the organic store brands), as opposed to economic brands. It takes place in the current environmental considerations showing the important role played by the packaging in determining the store brand equity. Design/methodology/approach A PLS Path model divided into four sub-models enables the authors to make specific predictions about customers’ purchase intentions. It also provides a concise operational calculation of the brand equity of each studied store brand. Findings Results show that economic brands build their equity with reinforced packaging, and organic brands maximise their brand equity by using simple packaging. In general, reinforced packaging improves the perceived quality of economic store brands but destroys that of organic brands. The calculations of overall equity scores for each studied store brand reveal that economic brands could benefit from further development whilst organic brands already maximise their equity. Practical implications Results will enable large retailers to develop effective campaigns focussing on perceived quality and more specifically by designing packaging that are suitable for the positioning of their brands – a simple packaging for organic brands and a reinforced packaging for economic brands to maximise customers’ value. Originality/value This is one of the first studies to deepen the store brand equity, comparing two contrasting types of brands, by studying specifically variations of the levels of customers’ perceived quality depending of two types of packaging.


Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 227 ◽  
Author(s):  
Camila Favaro ◽  
Ilton Baraldi ◽  
Fernanda Casciatori ◽  
Cristiane Farinas

Soluble coffee offers the combined benefits of high added value and practicality for its consumers. The hydrolysis of coffee polysaccharides by the biochemical route, using enzymes, is an eco-friendly and sustainable way to improve the quality of this product, while contributing to the implementation of industrial processes that have lower energy requirements and can reduce environmental impacts. This work describes the production of hydrolytic enzymes by solid-state fermentation (SSF), cultivating filamentous fungi on waste from the coffee industry, followed by their application in the hydrolysis of waste coffee polysaccharides from soluble coffee processing. Different substrate compositions were studied, an ideal microorganism was selected, and the fermentation conditions were optimized. Cultivations for enzymes production were carried out in flasks and in a packed-bed bioreactor. Higher enzyme yield was achieved in the bioreactor, due to better aeration of the substrate. The best β-mannanase production results were found for a substrate composed of a mixture of coffee waste and wheat bran (1:1 w/w), using Aspergillus niger F12. The enzymatic extract proved to be very stable for 24 h, at 50 °C, and was able to hydrolyze a considerable amount of the carbohydrates in the coffee. The addition of a commercial cellulase cocktail to the crude extract increased the hydrolysis yield by 56%. The production of β-mannanase by SSF and its application in the hydrolysis of coffee polysaccharides showed promise for improving soluble coffee processing, offering an attractive way to assist in closing the loops in the coffee industry and creating a circular economy.


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