We report a continuous nanoscale encapsulation of cancer drugs 5-Fluorouracil (FU) and Paclitaxel into biocompatible polycaprolactone (PCL) nanofibers (NFs) using core-sheath electrospinning process. A high potential electric field of 19–23.2 kV was used to draw a compound solution jet from a specialized coaxial spinneret. Using of DMF in both core and Sheath resulted in NFs within 50–160 nm along with large beaded structures. Addition of Trichloromethane (TCM) or Trifluoroethanol (TFE) in sheath turned NFs in more uniform and thin fiber structure. The diameter range for paclitaxel encapsulated fibers was 22–90 nm with encapsulation efficiency of 77.5% and the amount of drug was only 4 to 5% of sheath polymer. Addition of PVA within core resulted drug nanocrystal formation outside of sheath and poor encapsulation efficiency (52%) with rapid initial release (52–53%) in first 3 days. Drug release test of NFs in different pH exhibited increase of release rate with the decrease of media pH. In-vitro cell viability test with FU encapsulated NFs in human prostatic cancer PC3 cells exhibited 38% alive cells at 5 μM concentration while in pristine FU 43% cells were alive. Paclitaxel encapsulated NFs with breast cancer cells also exhibited increased efficacy in comparison to pristine anticancer drugs. Continuous decrease of cell density indicated the slow release of cancer drugs from the NFs. Both PCL+Paclitaxel and PCL+5FU treated conditions caused breast cancer cell death between 40% to 50%.

Cellulose acetate (CA) fibers were reinforced with multi-walled carbon nanotubes (MWCNTs) at 0.5%, 1.0%, 1.5% and 2.0%. Yield strength, ultimate tensile strength, fracture strain and toughness of the nanocomposite fiber increased up to 1.5 wt. % of the carbon nanotube (CNT) loading, however, further inclusion (2.0%) of MWCNTs in CA decreased the mechanical properties. Experimental properties were also compared with analytical predictions using a Shear lag model for strength and the rule of mixture for modulus. A solution spinning process, coupled with sonication, mixing, and extrusion, was used to process the CNT-reinforced composite fiber. Scanning electron microscopy (SEM) images of the cross sections of neat CA and CA-MWCNT fibers showed the formation of voids and irregular features. The enhanced interconnected fibrillation in the CNT-reinforced CA samples resulted in improved mechanical properties, which were observed by tensile testing. Fourier transform infrared spectroscopy (FTIR) spectra showed the area under the curve for C-H bonding after the inclusion of CNT. There was no significant shift of wavenumber for the inclusion of MWCNT in the CA matrix, which indicates that the sonication process of the CNT-loaded solution did not degrade the CA bonding structure.

The process of heat exchange between two fluids that are at different temperatures and separated by a solid wall occurs in many engineering applications. The device used to implement this exchange is termed a heat exchanger (HE), and specific applications may be found in space heating and air-conditioning, power generation, waste heat recovery, and chemical processing. Increasing heat transfer coefficient and making heat exchanger compact for various applications like in spacecraft, underwater vehicle, unmanned Ariel vehicle is one of the main challenges. Biologically-inspired design (or BID) has become an important and increasingly wide-spread movement in design for environmentally-conscious sustainable development. By definition, BID is based on cross-domain analogies; further, biologically-inspired approaches to design have a certain degree of openness to innovation. Compact heat exchanger can reduce the space and weight of any locomotives and spacecraft. Structural elements inspired from nature possess compactness and stability. Honeycomb structure allows minimize the spacing between cells which makes it possible to use thinnest possible metal boundary wall between two fluids. A rectangle structure can also do the same thing but it has less surface area, which will essentially decrease the volume of heat exchanger. Honeycomb structure provides high surface area to volume ratio which can be utilized to increase heat transfer coefficient of a heat exchanger and thus make compact system. In this computational study, bio-inspired simple honeycomb structured and spiral finned honeycomb structured counter flow heat exchanger has been three dimensionally simulated using finite element methods in commercial software COMSOL. This work is used to reduce the weight of heat exchangers in steam reforming reactors. There is a good correlation when the fluid temperature is the same in all cells. There is also a good temperature gradient in the fluid owing to laminar flow. 3D modeling showed that a careful representation of the inlet is needed for realistic results. A tube-shell heat exchanger is also simulated using FEA in COMSOL. Spiral finned heat exchanger provides additional surface area in cost of pressure drop. The performance characteristics of honeycomb heat exchanger showed an increase in heat transfer rate with least vortex formation.

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