This paper proposes a novel technique for fabricating micro patterns of glutaraldehyde (GA)-crosslinked gelatin. It provides another means to crosslink gelatin other than using photo-sensitizing agents, and the micro patterns of GA-crosslinked gelatin can still be made successfully by accessing conventional photolithography. A much less toxic and increased biocompatible approach to strengthening the gelatin microstructures can be developed according to this idea. This paper also describes a potential methodology for using GA-crosslinked gelatin patterns as single-cell culture bases. The best spatial resolution of the micro gelatin bases can reach 10 µm, and the selective growing density of human Mesenchymal stem cells on the gelatin patterns surpasses the density on the glass substrate by 2–3 orders of magnitude.

Quadcopters represent rotary wing configuration of the Unmanned Aerial Vehicles (UAVs) with immense application potential in industrial and strategic contexts. Tradeoff between flight endurance and payload capacity renders design optimization of UAVs a critical activity with substantial impact on the application possibilities. Among the structural parts of a typical Quadcopter, the central body frame constitutes major portion of the total weight. The present study aims at reduction of the frame weight while conforming with structural integrity requirements, through an integrated approach involving topology optimization, part consolidation and design for additive manufacturing (DFAM). Commercial UAV designs consist of multiple parts and fastening elements that necessitate considerable time and effort for assembly. This study reengineers the frame as a monocoque structure with desirable outcomes of weight reduction and less assembly time. The reengineered Quadcopter structure is manufactured through Fused Filament Fabrication (FFF) and characterized with reference to structural, vibrational and fatigue characteristics. Concomitant application of modal analysis, computational fluid dynamics and wind tunnel testing reveals close match between theoretical estimates and experimental results. Assembly and field trials of the monocoque Quadcopter structure affirm betterment of operational superiority and endurance vis-a-vis commercial UAV designs.

In the body of research relevant to high-performance flapping micro air vehicles (MAV), development of light-weight, compact and energy-efficient flapping mechanisms occupies a position of primacy due to its direct impact on the flight performance and mission capability. Realization of such versatile flapping mechanism with additional ability of producing thrust levels that fulfill requirements of cruising forward flight and vertical take-off and landing (VTOL) conditions demand extensive design validation and performance evaluation. This paper presents a concerted approach for mechanism development of a 20 cm span flapping MAV through an iterative design process and synergistic fabrication options involving electrical-discharge-wire-cutting (EDWC) and injection molding. Dynamic characterization of each mechanism is done through high speed photography, power take-off measurement, wind tunnel testing and proof-of-concept test flights. The research outcome represents best-in-class mechanism for a 20 cm span flapping MAV with desirable performance features of extra-large flapping stroke up to 100°, minimal transverse vibrations and almost no phase lag between the wings.