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Author Ogunmodede, O.; Lamas, P.; Brickey, A.; Bogin, G.; Newman, A.
Title Underground production scheduling with ventilation and refrigeration considerations Type
Year 2022 Publication Optimization And Engineering Abbreviated Journal Optim. Eng.
Volume 23 Issue 3 Pages 1677-1705
Keywords Underground mine scheduling; Integer programming applications; Resource-constrained project scheduling; Ventilation; Diesel equipment; Refrigeration
Abstract Underground mine production scheduling determines when, if ever, activities associated with the extraction of ore should be executed. The accumulation of heat in the mine where operators are working is a major concern. At the time of this writing, production scheduling and ventilation decisions are not made in concert. Correspondingly, heat limitations are largely ignored. Our mixed-integer program maximizes net present value subject to constraints on precedence, and mill and extraction capacities with the consideration of heat using thermodynamic principles, while affording the option of activating refrigeration to mitigate heat accumulation. In seconds to hours, depending on the problem size (up to thousands of activities and 900 daily time periods), a corresponding methodology that exploits the mathematical problem structure provides schedules that maintain a safe working environment for mine operators; optimality gaps are no more than 15% and average less than half that for otherwise-intractable instances.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1389-4420 ISBN Medium
Area Expedition Conference
Notes WOS:000741919400001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1519
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Author Thandapani, P.; Aepuru, R.; Beron, F.; Mangalaraja, R.V.; Varaprasad, K.; Zabotto, F.L.; Jimenez, J.A.; Denardin, J.C.
Title Multiferroic Electroactive Polymer Blend/Ferrite Nanocomposite Flexible Films for Cooling Devices Type
Year 2023 Publication ACS Applied Polymer Materials Abbreviated Journal ACS Appl. Polym. Mater.
Volume 5 Issue 8 Pages 5926-5936
Keywords i-caloric; magnetic refrigeration; multiferroics; ferroelectric polymers; nanocomposites; ferrites
Abstract In recent days, the interest toward the development ofmulticaloricmaterials for cooling application is increasing, whereas multiferroicmaterials would be the suitable alternative to the conventional refrigerants.To explore them, the poly(methyl methacrylate)/poly(vinylidenefluoride-co-hexafluoropropylene) (PMMA/PVDF-HFP) blend and PMMA/PVDF-HFP/Zn0.5Cu0.5Fe2O4 flexible multiferroicnanocomposite films were fabricated by the solution casting method.The structural analyses prove that the strong interfacial interactionbetween the PMMA/PVDF-HFP blend and the Zn0.5Cu0.5Fe2O4 (ZCF) through hydroxyl (-OH) andcarbonyl group bonding with PVDF-HFP enhanced the thermal stabilityand suppressed the electroactive & beta; phase from 67 to 62%. Experimentalresults show that 10 wt % of superparamagnetic ZCF nanoparticles witha particle size of 6.8 nm induced both the magnetocaloric and magnetoelectriceffects in a nonmagnetic PMMA/PVDF-HFP ferroelectric matrix at roomtemperature. A set of isothermal magnetization curves were recordedin the magnetic field strength of 0-40 kOe and a temperaturerange of 2-400 K. The maximum magnetic entropy changes (& UDelta;S (M)) of -0.69 J & BULL;kg(-1) K-1 of ZCF nanoparticles and -0.094 J & BULL;kg(-1) K-1 of PMMA/PVDF-HFP/ZCF nanocompositesshowed an interesting table-like flat variation in the temperaturerange of 100-400 K as a function of the magnetic field. Thesamples display a large temperature span with a relative cooling power of 293 and 40 J & BULL;kg(-1) for ZCF and PMMA/PVDF-HFP/ZCF,respectively. The magnetoelectric effect of the PMMA/PVDF-HFP/ZCFcomposite was proved, but it generated only 1.42 mV/m & BULL;Oe in theapplied field of 5 kOe. Hence, the entropy change of the present nanocompositewas only due to the magnetocaloric effect, where the magnetoelectriccross-coupling coefficient was negligible. The multicaloric effectcould be established if the nanocomposite showed a larger magnetoelectriccross-coupling in addition to the magnetocaloric effect. This approachprovides the research findings in functional multiferroic polymernanocomposites for miniaturized cooling devices.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2637-6105 ISBN Medium
Area Expedition Conference
Notes WOS:001030514100001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1848
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