Documents disponibles écrits par cet auteur

Quantitative analysis of grain boundary fracture in the breakage of single multiphase particles using X-ray microtomography procedures / D. García in Minerals engineering, Vol. 22 N° 3 (Fevrier 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 3 (Fevrier 2009) . - pp. 236–243 Titre : Quantitative analysis of grain boundary fracture in the breakage of single multiphase particles using X-ray microtomography procedures Type de document : texte imprimé Auteurs : D. García, Auteur ; C.L. Lin, Auteur ; J.D. Miller, Auteur Année de publication : 2009 Article en page(s) : pp. 236–243 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth  flotation  Liberation  Liberation  analysis  Mineral  processing  Ore  mineralogy Index. décimale : 622 Industrie minière Résumé : Direct determination of intergranular fracture during multiphase particle breakage is a difficult task to achieve. Perhaps the only method of analysis is measurement of interphase area before and after comminution. Conservation of interfacial area after crushing is indicative of transgranular random breakage. On the other hand, if interfacial area is diminished after breakage some degree of preferential grain boundary fracture has occurred. For complete liberation of all grains after crushing the interfacial area goes to zero. Thus the interfacial area criterion is an important metric to assess the significance of preferential grain boundary fracture for different breakage conditions. This study describes the development of procedures for detailed analysis to quantify the extent of preferential grain boundary fracture for different breakage conditions using X-ray microtomography (XMT). The breakage of single multiphase copper ore particles (3 mm cubic particles) by slow compression is examined. Procedures developed for interfacial area measurements are discussed and determination of the extent of grain boundary fracture of multiphase particles for different breakage conditions is presented. For the copper ore studied, it is shown that preferential grain boundary fracture occurs at low energy dissipation rates. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687508001842 [article] Quantitative analysis of grain boundary fracture in the breakage of single multiphase particles using X-ray microtomography procedures [texte imprimé] / D. García, Auteur ; C.L. Lin, Auteur ; J.D. Miller, Auteur . - 2009 . - pp. 236–243. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 3 (Fevrier 2009) . - pp. 236–243 Mots-clés : Froth  flotation  Liberation  Liberation  analysis  Mineral  processing  Ore  mineralogy Index. décimale : 622 Industrie minière Résumé : Direct determination of intergranular fracture during multiphase particle breakage is a difficult task to achieve. Perhaps the only method of analysis is measurement of interphase area before and after comminution. Conservation of interfacial area after crushing is indicative of transgranular random breakage. On the other hand, if interfacial area is diminished after breakage some degree of preferential grain boundary fracture has occurred. For complete liberation of all grains after crushing the interfacial area goes to zero. Thus the interfacial area criterion is an important metric to assess the significance of preferential grain boundary fracture for different breakage conditions. This study describes the development of procedures for detailed analysis to quantify the extent of preferential grain boundary fracture for different breakage conditions using X-ray microtomography (XMT). The breakage of single multiphase copper ore particles (3 mm cubic particles) by slow compression is examined. Procedures developed for interfacial area measurements are discussed and determination of the extent of grain boundary fracture of multiphase particles for different breakage conditions is presented. For the copper ore studied, it is shown that preferential grain boundary fracture occurs at low energy dissipation rates. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687508001842

Significance of liberation characteristics in the fatty acid flotation of Florida phosphate rock / Mohamed I. Al-Wakeel in Minerals engineering, Vol. 22 N° 3 (Fevrier 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 3 (Fevrier 2009) . - pp. 244–253 Titre : Significance of liberation characteristics in the fatty acid flotation of Florida phosphate rock Type de document : texte imprimé Auteurs : Mohamed I. Al-Wakeel, Auteur ; C.L. Lin, Auteur ; Jan D. Miller, Auteur Année de publication : 2009 Article en page(s) : pp. 244–253 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Froth  flotation  Liberation  analysis  Mineralogy  Florida  phosphate  rock Index. décimale : 622 Industrie minière Résumé : Phosphate flotation has been used by industry for more than a half century but still faces many technical challenges. Such challenges include not only the selection of the chemical reagents but the characteristics of the feed itself. This paper deals with the investigation of feed characteristics and how these characteristics affect the flotation separation efficiency of feed material from a selected phosphate operation. Specifically why some feed, from the same mine, is efficiently separated with high recovery (good feed) while other feed is more difficult to separate (bad feed). The study was conducted using both traditional analytical techniques and more advanced techniques such as X-ray microtomography. The results reveal that the bad feed was highly porous, coarser in size, and, most significantly, exhibits a lower degree of liberation. Such bad feed was inefficiently separated by fatty acid flotation and improved recovery would require controlled grinding in order to improve the extent of liberation. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750800188X [article] Significance of liberation characteristics in the fatty acid flotation of Florida phosphate rock [texte imprimé] / Mohamed I. Al-Wakeel, Auteur ; C.L. Lin, Auteur ; Jan D. Miller, Auteur . - 2009 . - pp. 244–253. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 3 (Fevrier 2009) . - pp. 244–253 Mots-clés : Froth  flotation  Liberation  analysis  Mineralogy  Florida  phosphate  rock Index. décimale : 622 Industrie minière Résumé : Phosphate flotation has been used by industry for more than a half century but still faces many technical challenges. Such challenges include not only the selection of the chemical reagents but the characteristics of the feed itself. This paper deals with the investigation of feed characteristics and how these characteristics affect the flotation separation efficiency of feed material from a selected phosphate operation. Specifically why some feed, from the same mine, is efficiently separated with high recovery (good feed) while other feed is more difficult to separate (bad feed). The study was conducted using both traditional analytical techniques and more advanced techniques such as X-ray microtomography. The results reveal that the bad feed was highly porous, coarser in size, and, most significantly, exhibits a lower degree of liberation. Such bad feed was inefficiently separated by fatty acid flotation and improved recovery would require controlled grinding in order to improve the extent of liberation. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750800188X

Single-machine scheduling of proportionally deteriorating jobs by two agents / S. Gawiejnowicz in Journal of the operational research society (JORS), Vol. 62 N° 11 (Novembre 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 11 (Novembre 2011) . - pp. 1983–1991 Titre : Single-machine scheduling of proportionally deteriorating jobs by two agents Type de document : texte imprimé Auteurs : S. Gawiejnowicz, Auteur ; W-C. Lee, Auteur ; C.L. Lin, Auteur Année de publication : 2011 Article en page(s) : pp. 1983–1991 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Agent  scheduling  Deteriorating  jobs  Total  tardiness  The  number  of  tardy  jobs  Branch-and-bound  algorithm  Evolutionary  algorithm Index. décimale : 001.424 Résumé : We consider a problem of scheduling a set of independent jobs by two agents on a single machine. Every agent has its own subset of jobs to be scheduled and uses its own optimality criterion. The processing time of each job proportionally deteriorates with respect to the starting time of the job. The problem is to find a schedule that minimizes the total tardiness of the first agent, provided that no tardy job is allowed for the second agent. We prove basic properties of the problem and give a lower bound on the optimal value of the total tardiness criterion. On the basis of these results, we propose a branch-and-bound algorithm and an evolutionary algorithm for the problem. Computational experiments show that the exact algorithm solves instances up to 50 jobs in a reasonably short time and that solutions obtained by the metaheuristic are close to optimal ones. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n11/abs/jors2010171a.html [article] Single-machine scheduling of proportionally deteriorating jobs by two agents [texte imprimé] / S. Gawiejnowicz, Auteur ; W-C. Lee, Auteur ; C.L. Lin, Auteur . - 2011 . - pp. 1983–1991. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 11 (Novembre 2011) . - pp. 1983–1991 Mots-clés : Agent  scheduling  Deteriorating  jobs  Total  tardiness  The  number  of  tardy  jobs  Branch-and-bound  algorithm  Evolutionary  algorithm Index. décimale : 001.424 Résumé : We consider a problem of scheduling a set of independent jobs by two agents on a single machine. Every agent has its own subset of jobs to be scheduled and uses its own optimality criterion. The processing time of each job proportionally deteriorates with respect to the starting time of the job. The problem is to find a schedule that minimizes the total tardiness of the first agent, provided that no tardy job is allowed for the second agent. We prove basic properties of the problem and give a lower bound on the optimal value of the total tardiness criterion. On the basis of these results, we propose a branch-and-bound algorithm and an evolutionary algorithm for the problem. Computational experiments show that the exact algorithm solves instances up to 50 jobs in a reasonably short time and that solutions obtained by the metaheuristic are close to optimal ones. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n11/abs/jors2010171a.html