Thermal storage has been considered as an important measure to extend the operation of a eoneentrated solar power plant by providing more eleetricity and meeting the peak demand of power in the time period from dusk to late night everyday, or even providing power on eloudy days. Diseussed in this paper is thermal energy storage in a thermoeline tank having a solid filler material. To provide more knowledge for designing and operating of sueh a thermoeline storage system, this paper firstly presents the application of method of characteristics for numerieally predicting the heat charging and discharging process in a paeked bed thermocline storage tank. Nondimensional analysis of governing equations and numerical solution schemes using the method of characteristics were presented. The numerical method proved to be very efficient, accurate; required minimal computations; and proved versatile in simulating various operational conditions for which analytical methods cannot always provide solutions. Available analytical solutions under .simple boundary and initial conditions were used to validate the numerical modeling and computation. A validation of the modeling by eomparing the simulation results to experimental test data from literature also confirmed the effectiveness of the model and the related numerieal solution method. Finally, design procedures using the numerical modeling tool were discussed and other issues related to operation of a thermoeline storage system were also studied.

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SUMMARY Generating mammalian cells with desired mitochondrial DNA (mtDNA) sequences is enabling for studies of mitochondria, disease modeling, and potential regenerative therapies. MitoPunch, a high-throughput mitochondrial transfer device, produces cells with specific mtDNA-nuclear DNA (nDNA) combinations by transferring isolated mitochondria from mouse or human cells into primary or immortal mtDNA-deficient (ρ0) cells. Stable isolated mitochondrial recipient (SIMR) cells isolated in restrictive media permanently retain donor mtDNA and reacquire respiration. However, SIMR fibroblasts maintain a ρ0-like cell metabolome and transcriptome despite growth in restrictive media. We reprogrammed non-immortal SIMR fibroblasts into induced pluripotent stem cells (iPSCs) with subsequent differentiation into diverse functional cell types, including mesenchymal stem cells (MSCs), adipocytes, osteoblasts, and chondrocytes. Remarkably, after reprogramming and differentiation, SIMR fibroblasts molecularly and phenotypically resemble unmanipulated control fibroblasts carried through the same protocol. Thus, our MitoPunch “pipeline” enables the production of SIMR cells with unique mtDNA-nDNA combinations for additional studies and applications in multiple cell types.

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