Internal Model Control of a Domestic Microwave for Carbon Composite Curing

This paper outlines the conversion of a domestic microwave oven for use in composite curing applications. It compares several strategies for temperature control. The converted oven has vacuum ports, connectors, and fiber optic thermocouple sensors. Experimental data are provided for each control strategy based on a 200 mm× 200 mm eight-ply prepreg laminate. The degree of cure is established for the test samples by thermal analysis techniques. Multiphysics simulation is used to model the electromagnetic and heating effects in the system, and a common and inexpensive method of approximating the available microwave power is used. The low cost of the microwave components and the ease of conversion are desirable characteristicsin this application

Toward Automatic Label-Free Whispering Gallery Modes Biodetection with a Quantum Dot-Coated Microsphere Population

We explore a new calibration-free approach to biodetection based on whispering gallery modes (WGMs) without a reference measure and relative shifts. Thus, the requirement to keep track of the sensor position is removed, and a freely moving population of fluorophore-doped polystyrene microspheres can now fulfill this role of sensing resonator. Breaking free from fixed surface-based biosensing promotes adhesion between the microsphere sensors and the analytes since both can now be thoroughly mixed. The 70-nm-wide spectrum of green fluorescent microbeads allows us to monitor over 20 WGMs simultaneously without needing evanescent light coupling into the microspheres, hence enabling remote sensing. Since the exact radius of each microsphere is unknown a priori, it requires algorithmic analyses to obtain a reliable result for the refractive index of a solution. We first test our approach with different solutions of alcohol in water obtaining 3 × 10−4 precision on the refractive index at lower concentrations. Then, the solutions of bacterial spores in water yield clear evidence of biodetection in the statistical analysis of WGMs from 50 microspheres. To extend the fluorescence spectral range of our WGM sensors, we present preliminary results on coating microspheres with CdSe/ZnS quantum dots

Biofunctionalization of 3D nylon 6,6 scaffolds using a two-step surface modification

Nylon is a relatively inert polymer. The ability to easily functionalize nylon with biomolecules will improve the utilization of nylon in biological systems. A potential use of the biofunctionalized nylon scaffolds is in devices for cell therapeutics that can specifically select cells present in small numbers, such as hematopoietic stem cells. This study developed a versatile and simple two-step technique combining oxygen plasma treatment with wet silanization to graft biomolecules onto nylon 6,6 3D porous scaffolds. Scaffolds that were exposed to oxygen plasma exhibited up to 13-fold increase in silane attachment ((3-mercaptopropyl)trimethoxysilane/(3-aminopropyl)trimethoxysilane) compared to untreated scaffolds. To address the limitation of nondestructive characterization of the surface chemistry of 3D scaffolds, fluorescent CdSe/ZnS nanoparticles were used as a reporting tool for -NH(2) functionalized surfaces. Scaffolds that were covalently bound with neutravidin protein remained stable in phosphate buffered saline up to four months. Functionality of the neutravidin-grafted scaffolds was demonstrated by the specific binding of CD4 cells to the scaffold via CD4-specific antibody. Ultimately, these neutravidin-functionalized 3D nylon scaffolds could be easily customized on demand utilizing a plethora of biotinylated biomolecules (antibodies, enzymes and proteins) to select for specific cell of interest. This technique can be extended to other applications, including the enhancement of cell-scaffold interactions