A 3D printed drug delivery implant formed from a dynamic supramolecular polyurethane formulation

Using a novel molecular design approach, we have prepared a thermo-responsive supramolecular polyurethane as a matrix material for use in drug eluting implants. The dynamic supramolecular polyurethane (SPU) is able to self-assemble through hydrogen bonding and π-π stacking interactions, resulting in an addressable polymer network with a relatively low processing temperature. The mechanical properties of the SPU demonstrated the material was self-supporting, stiff, yet flexible thus making it suitable for hot-melt extrusion processing, inclusive of related 3D printing approaches. Cell-based toxicity assays revealed the SPU to be non-toxic and therefore a viable candidate as a biocompatible polymer for implant applications. To this end, the SPU was formulated with paracetamol (16 %w/w) and 4 wt% or 8 wt% poly(ethylene glycol) (PEG) as an excipient and hot melt extruded at 100 °C to afford a 3D printed prototype implant to explore the extended drug release required for an implant and the potential manipulation of the release profile. Furthermore, rheological, infra-red spectroscopy, powder X-ray diffraction and scanning electron microscopy studies revealed the chemical and physical properties and compatibility of the formulation components. Successful release of paracetamol was achieved from in vitro dissolution studies and it was predicted that the drug would be released over a period of up to 8.5 months with hydrophilic PEG being able to influence the release rate. This extended release time is consistent with applications of this novel dynamic polymer as a drug eluting implant matrix

Analytical techniques and instrumentation: A compilation

Technical information on developments in instrumentation is arranged into four sections: (1) instrumentation for analysis; (2) analysis of matter; (3) analysis of electrical and mechanical phenomena; and (4) structural analysis. Patent information for two of the instruments described is presented

Marquette Interchange Perpetual Pavement Instrumentation Project - Phase II

This report presents findings from the second phase of the Marquette Interchange instrumentation project and focuses on the maintenance of data recordation systems, development of computer programs to analyze data, and development of data packages for redistribution. The product of this research is a set of data which includes dynamic pavement response due to live traffic, vehicle information (weight, class, length, et cetera), and environmental data for the test site. The tasks within this project were not oriented for findings regarding pavement performance, but important and helpful conclusions can be drawn for similar future projects. The recordation systems have been maintained and recordation has been continuous. A handful of sensors did require attention and only a fraction of the critical strain sensors have ceased to function, making the project a success. The results of the computer programs written to analyze data show that reasonable accuracy has been achieved. Future work can help to generate more intricate programming making the processes more accurate

Testing of a flat conductor cable baseboard system for residential and commercial wiring

The results of extensive testing (mechanical, electrical, chemical, environmental, thermal, and analytical) are reported for a flat conductor cable baseboard system for residential and commercial wiring. In all of the tests, Underwriters Laboratories (UL) Standards, UL Tentative Test Programs, or Accepted Engineering Practices were followed during test selection, test setup, and test accomplishment

Techniques for intergranular crack formation and assessment in alloy 600 base and alloy 182 weld metals

Background: A technique developed to produce artificial intergranular stress corrosion cracks in structural components was applied to thick, forged alloy 600 base and alloy 182 weld metals for use in the qualification of nondestructive examination techniques for welded components in nuclear power plants. Methods: An externally controlled procedure was demonstrated to produce intergranular stress corrosion cracks that are comparable to service-induced cracks in both the base and weld metals. During the process of crack generation, an online direct current potential drop method using array probes was used to measure and monitor the sizes and shapes of the cracks. Results: A microstructural characterization of the produced cracks revealed realistic conformation of the crack faces unlike those in machined notches produced by an electrodischarge machine or simple fatigue loading using a universal testing machine. Conclusion: A comparison with a destructive metallographic examination showed that the characteristics, orientations, and sizes of the intergranular cracks produced in this study are highly reproducible. ??? 2015, Published by Elsevier Korea LLC on behalf of Korean Nuclear Societyclose0

Comparison of 60# white converter kraft to 60# white Velumina kraft for use in multi-wall paper bags

This study was designed to analyze the change from 60# Gilman white converter kraft to 60# Georgia-Pacific white Velumina kraft on the outer ply of multi-wall paper bags. Logisitical issues were driving the change but Good Manufacturing Practices had to be observed as the bags were being used for Food and Drug Administration registered medicated animal feed products. The papers were tested for physical strength and print quality. Results showed that the 60# Georgia-Pacific white Velumina kraft was equal to the 60# Gilman white converter kraft in physical strength and slightly better in print quality. Both papers met the performance standards of the current application and either paper could be used with confidence that bag performance would not suffer

Enhanced mechanical, thermal and flame retardant properties by combining graphene nanosheets and metal hydroxide nanorods for Acrylonitrile–Butadiene–Styrene copolymer composite

Three metal hydroxide nanorods (MHR) with uniform diameters were synthesized, and then combined with graphene nanosheets (GNS) to prepare acrylonitrile–butadiene–styrene (ABS) copolymer composites. An excellent dispersion of exfoliated two-dimensional (2-D) GNS and 1-D MHR in the ABS matrix was achieved. The effects of combined GNS and MHR on the mechanical, thermal and flame retardant properties of the ABS composites were investigated. With the addition of 2 wt% GNS and 4 wt% Co(OH)2, the tensile strength, bending strength and storage modulus of the ABS composites were increased by 45.1%, 40.5% and 42.3% respectively. The ABS/GNS/Co(OH)2 ternary composite shows the lowest maximum weight loss rate and highest residue yield. Noticeable reduction in the flammability was achieved with the addition of GNS and Co(OH)2, due to the formation of more continuous and compact charred layers that retarded the mass and heat transfer between the flame and the polymer matrix

Essential work of fracture of poly(ϵ-caprolactone)/boehmite alumina nanocomposites: Effect of surface coating

The essential work of fracture (EWF) approach has been adopted to reveal the effect of nanofillers on the toughness of poly(ε-caprolactone)/boehmite alumina (PCL/BA) nanocomposites. Synthetic BA particles of different surface treatments were dispersed in the PCL matrix by extrusion melt compounding. The morphology of composites was studied by scanning electron microscopy. Differential scanning calorimetry and wide angle X-ray scattering were used to detect changes in the crystalline structure of PCL. Besides the mode I type EWF tests, dynamic mechanical analysis (DMA) and quasi-static tensile tests were applied to study the effect of BA nanofillers on the mechanical properties. BA was homogenously dispersed and acted as heterogeneous crystallization nucleant and non-reinforcing filler in PCL. The tensile modulus and yield strength slightly increased, whereas the yield strain decreased with increasing BA content (up to 10 wt%). Effect of the BA surface treatment with octylsilane (OS) was negligible by contrast to alkylbenzene sulphonic acid (OS2). Like the tensile mechanical data, the essential and non-essential work of fracture parameters did not change significantly, either. Improved PCL/BA adhesion in case of OS2 treatment excluded the usual EWF treatise. This was circumvented by making use of energy partitioning between yielding and necking. The yielding related essential work of fracture decreased while the non-essential one increased with BA content and with better interfacial adhesion. This was attributed to the effect of matrix/filler debonding

Coating for prevention of titanium combustion

A limited number of coating options for titanium gas turbine engine components were explored with the objective of minimizing potential combustion initiation and propagation without adversely affecting component mechanical properties. Objectives were met by two of the coatings, ion-plated platinum plus electroplated copper plus electroplated nickel and ion vapor deposited aluminum