Integrated SOFC/GT Systems with Improved Dynamic Capabilities for Mobile Applications.

This work is focused on developing control and system integration solutions to achieve rapid and reliable load following operation of solid oxide fuel cell/gas turbine (SOFC/GT) systems for mobile applications. Both the traditional recuperating-SOFC/GT system and the newly proposed sprinter-SOFC/GT system are studied through model-based methodologies. It is shown that solutions developed in this research could enhance system performance and meet operating objectives. For the recuperating system, the generator/motor (G/M) dual mode operation and its implications are investigated. Active shaft load control is used to manage transients by: (a) pre-conditioning of G/M power for load step-up transients; and (b) absorbing the excessive power through motoring operation for load step-down transients. Feedback and optimization algorithms are developed. By taking advantage of the dual operating G/M, better trade-offs between power tracking and thermal safety can be achieved, the battery requirements can be reduced and system performance can be enhanced. The sprinter-SOFC/GT system, which has far superior load following capability than traditional systems, is proposed in this research. In the system, the SOFC operated at constant temperature provides only the baseline power with high efficiency while the GT-generator’s transient capability will be fully explored for fast dynamic load following. System design and control framework suited for the proposed system are investigated. An SOFC operational strategy is derived to keep fairly constant SOFC power and temperature over the entire load range. A design procedure is also developed to determine various component sizes. The “actual” operational envelope is determined by integrating the SOFC power/temperature constraints with safety factors. An optimization problem is proposed to determine the optimal feed-forward operation map. Control analysis and feedback design are presented for the sprinter system. The stability of steady-state operation is studied through numerical simulations and linearized analysis of a simplified “2-state” model. Open-loop instability was identified for the low and medium airflow regions. Open-loop analysis and relative gain array (RGA) technique are used to gain insights on system operation and input-output interactions. Feedback control design is performed to address transient issues. The sprinter system achieves far superior performance than its recuperating counterpart for fast and safe load following.PhDNaval Architecture and Marine EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/110400/1/zhenzjia_1.pd

SWheg: A Wheel-Leg Transformable Robot With Minimalist Actuator Realization

This article presents the design, implementation, and performance evaluation of SWheg, a novel modular wheel-leg transformable robot family with minimalist actuator realization. SWheg takes advantage of both wheeled and legged locomotion by seamlessly integrating them on a single platform. In contrast to other designs that use multiple actuators, SWheg uses only one actuator to drive the transformation of all the wheel-leg modules in sync. This means an N-legged SWheg robot requires only N+1 actuators, which can significantly reduce the cost and malfunction rate of the platform. The tendon-driven wheel-leg transformation mechanism based on a four-bar linkage can perform fast morphology transitions between wheels and legs. We validated the design principle with two SWheg robots with four and six wheel-leg modules separately, namely Quadrupedal SWheg and Hexapod SWheg. The design process, mechatronics infrastructure, and the gait behavioral development of both platforms were discussed. The performance of the robot was evaluated in various scenarios, including driving and turning in wheeled mode, step crossing, irregular terrain passing, and stair climbing in legged mode. The comparison between these two platforms was also discussed

New tumor-targeted nanosized delivery carrier for oligonucleotides: characteristics in vitro and in vivo

Tianyang Zhou1,2, Xin Jia1, Huixiang Li3, Jin Wang3, Hongling Zhang1,2, Youmei A1,2, Zhenzhong Zhang1,21School of Pharmaceutical Sciences, 2Nanotechnology Research Center for Drugs, 3Department of Pathology, Medical School of Zhengzhou University, Zhengzhou, People’s Republic of ChinaBackground: The purpose of this study was to investigate the in vitro and in vivo characteristics of a new tumor-targeted nanosized delivery carrier for antisense oligonucleotide (ASON).Methods: Polyethylenimine (PEI) was used to condense ASON to form nanosized complexes (PEI/ASON), which were then modified using asparagine-glycine-arginine (NGR) peptide to obtain a tumor-targeted nanosized delivery carrier (NGR/PEI/ASON). The conditions required to form PEI/ASON were investigated.Results: A linear correlation between the natural logarithm of the N/P ratio (PEI to ASON) and the zeta potential of the PEI/ASON complexes was found, ranging from 1.5 to 5.0. The pH of the solution strongly influenced the zeta potential of the PEI/ASON complexes. PEI/ASON and NGR/PEI/ASON were stable in RPMI-1640 culture medium in the presence of Dextran 70. Incorporation of ASON into PEI/ASON and NGR/PEI/ASON complexes prevented degradation of ASON by DNase I.Conclusion: Both ASON/PEI and NGR/PEI/ASON complexes enhanced the uptake of ASON by EC9706 cells in vitro. In vivo, NGR/PEI/ASON complexes had the ability to target tumor tissues effectively.Keywords: nanosized delivery system, squamous cell carcinoma, antisense oligonucleotid