GRANULAR FLOW IN THE PRESENCE OF AN ELECTRIC FIELD

The granular flow in a vertical pipe in the presence of electric field E is studied. Depending upon its initial state and the applied field voltage the controlled flow rate remains in two phases, dilute flow or dense flow. For dilute flow, the electric field has no effect on the flow rate until V reaches a critical value Vj. At V = V 1} the flow rate drops abruptly and a transition of the particulate from dilute to dense flow occurs. For dense flow, the flow rate decreases monotonically with increasing V. A two-dimensional computer simulation has been done and the results agree qualitatively well with the experimental measurements

Browning of Pig White Preadipocytes by Co-Overexpressing Pig PGC-1α and Mice UCP1

Background/Aims: Brown adipose tissue (BAT) is critical for mammals’ survival in the cold environment. BAT-dependent non-shivering thermogenesis is attributed to uncoupling protein 1 (UCP1)’s disengagement of oxidative phosphorylation from ATP synthesis and dissipates energy as heat. Thus individuals with a substantial amount of BAT are better equipped during cold stress and less likely to become obese. Recently, our laboratory has shown pig adipocytes have no UCP1 protein. The inability of newborn piglets to generate heat contributed to its high death rate. Repairing the genetic defect of UCP1 in pig adipocytes has implications in defending against cold for piglets and developing an alternative treatment for human obesity. Methods: Q-PCR, western blotting (WB) and oxygen consumption measurement were used to enable functional UCP1 protein in preadipocytes. Immunoprecipitation (IP), chromatin immunoprecipitation (CHIP), and dual-luciferase reporter assay system were used to clarify the thermogenesis mechanism of functional UCP1. Results: Only co-overexpressing mice UCP1 and pig PGC-1α increased not only the mitochondrial number but also the uncoupled respiration rate in the transfected pig adipocytes. The functional mice UCP1 increased the pig PGC-1α activity through the AMPK-SIRT1 pathway. The active form PGC-1α interacted with transcription factors Lhx8, Zic1, ERRα, and PPARα to regulate the expression of mitochondrial energy metabolism and adipocytes browning-related genes. Conclusion: Our data suggest a model in which pig PGC-1α and mice UCP1 work collaboratively to restore uncoupling respiration in pig preadipocytes. These results have great implications for piglet survival and developing an alternative treatment for human obesity in the future

Granular Gas: Vibrating Walls, Two-Peak Distribution and Hydrodynamics

Vibrating walls, used to maintain the temperature in a granular gas, modify the system strongly. Most conspicuously, the usual one-peak velocity distribution splits into two, asymmetrically positioned. A surgical repair of the usual hydrodynamic description is presented that provides an account for, and an understanding of, the situation.Comment: 3 fi

Simulation research of the buffering capacity of non-convex particle system under impact loading

The behavior of granular materials under the action of external force is a fundamental problem for the dynamics of granular media. This paper investigates the buffering capacity of three-dimensional non-convex granular beds subjected to vertical impact using the discrete element methods. The results display the particle shape significantly affects the buffering capacity of the equal mass granular bed. And the influence of aspect ratio of non-convex particles on buffering capacity exhibits an obvious non-monotonicity. The functional mechanism of inter-particle friction is discussed. It is showed that the shape of the non-convex particles has a great effect on the contact number of granular system and probability density functions of inter-particle forces

Simulation research of the buffering capacity of non-convex particle system under impact loading

The behavior of granular materials under the action of external force is a fundamental problem for the dynamics of granular media. This paper investigates the buffering capacity of three-dimensional non-convex granular beds subjected to vertical impact using the discrete element methods. The results display the particle shape significantly affects the buffering capacity of the equal mass granular bed. And the influence of aspect ratio of non-convex particles on buffering capacity exhibits an obvious non-monotonicity. The functional mechanism of inter-particle friction is discussed. It is showed that the shape of the non-convex particles has a great effect on the contact number of granular system and probability density functions of inter-particle forces

Directed clustering in driven compartmentalized granular gas systems in zero gravity

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