Distributed augmented reality with 3-D lung dynamics--a planning tool concept.

Augmented reality (AR) systems add visual information to the world by using advanced display techniques. The advances in miniaturization and reduced hardware costs make some of these systems feasible for applications in a wide set of fields. We present a potential component of the cyber infrastructure for the operating room of the future: a distributed AR-based software-hardware system that allows real-time visualization of three-dimensional (3-D) lung dynamics superimposed directly on the patient's body. Several emergency events (e.g., closed and tension pneumothorax) and surgical procedures related to lung (e.g., lung transplantation, lung volume reduction surgery, surgical treatment of lung infections, lung cancer surgery) could benefit from the proposed prototype.     

The kinetics of polyurethane structural foam formation: Foaming and polymerization

Kinetic models have been developed to understand the manufacturing of polymeric foams, which evolve from low viscosity Newtonian liquids, to bubbly liquids, finally producing solid foam. Closed‐form kinetics are formulated and parameterized for PMDI‐10, a fast curing polyurethane, including polymerization and foaming. PMDI‐10 is chemically blown, where water and isocyanate react to form carbon dioxide. The isocyanate reacts with polyol in a competing reaction, producing polymer. Our approach is unique, although it builds on our previous work and the polymerization literature. This kinetic model follows a simplified mathematical formalism that decouples foaming and curing, including an evolving glass transition temperature to represent vitrification. This approach is based on IR, DSC, and volume evolution data, where we observed that the isocyanate is always in excess and does not affect the kinetics. The kinetics are suitable for implementation into a computational fluid dynamics framework, which will be explored in subsequent articles. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2945–2957, 2017     

Dissociated and Reconstituted Cartilage Microparticles in Densified Collagen Induce Local hMSC Differentiation

Current use of decellularized articular cartilage as a regenerative platform suffers from limited implant diffusion characteristics and cellular infiltration. Attempts to address this concern using decellularized cartilage microparticles allow for customized implant shape, tailored porosity, and improved cell infiltration. However, these developments utilize severe crosslinking agents that adversely affect cell differentiation, and fail to attain clinically relevant mechanical properties required for the implant survival. These issues have been overcome through the formation of a composite approach, combining the advantages of mature, decellularized tissue with tunable features of a reconstituted collagen hydrogel system. Through the application of a plastic compression regime, cellularized composite structures are formed that exceeded the percolation threshold of the cartilage microparticles and exhibited clinically relevant mechanical properties. Chemical reduction and mechanical reconstitution methods to investigate the contributions of glycosaminoglycan and collagenous components to chondrogenic induction and matrix properties have been utilized. With the inclusion of human mesenchymal stem cells into the composite system, microenvironment‐dependent cell morphology and phenotype when in contact with cartilage microparticles are shown. This work demonstrates a cartilage microparticle composite matrix with clinically relevant mechanical properties, and chondrogenic differentiation of human mesenchymal stem that infiltrate both native and chemically reduced cartilage microparticles.     

An overview of high temperature micro-ATR IR spectroscopy to monitor polymer reactions

High temperature micro-ATR IR spectroscopy has recently become available, allowing for convenient IR spectral acquisition at elevated temperatures. This study presents a perspective on using this capability to monitor polymer chemistry with an emphasis on the study of polymer cure reactions. Examples are provided to demonstrate how easily time-resolved data can be acquired at temperatures of up to 200 °C. IR signatures of the key reactions and basic cure kinetics are compared for a few specific resin systems, ranging from amine- and anhydride-cured epoxies, to benzoxazine, cyanate ester or polyurea cure. This approach allows an evaluation of cure chemistry and kinetics as a function of temperature, resin constituents, or catalyst addition. Similarly, in-situ thermo-oxidative degradation can be monitored, as shown for a thin film of solvent deposited hydroxyl-terminated polybutadiene. In conclusion, high temperature IR is very attractive for resin cure and composite material characterization or aspects of polymer degradation, wherever infrared spectral changes are involved as part of reactive chemistry.     

Thermal behavior of building walls in summer: Comparison of available analytical methods and experimental results for a case study

There is a wide variety of thermal analyses that can be used to characterize the thermal behavior of a wall under certain outdoor conditions. The selection of a particular wall configuration for a building project involves not only the outdoor climate, but also the whole building characteristics, orientation, percentage of glazed areas, occupation periods, lifestyles, etc. In this paper we apply common available methods for wall thermal analysis to two particular wall types, a massive brick wall and an insulated brick wall, in order to compare the information given by each method and to evaluate how these methods can help in the selection of a certain type of wall. The studied methods include the estimation of the wall time lag and decrement factor, the harmonically heated slab model, the Athanassouli’s method, and numerical simulations. The study was performed for the walls of a residence for university students and it was built in La Pampa (Argentina). Once the building was finished, the transient thermal behavior of two walls was monitored during one summer week. The experimental results are presented and the fitting with the thermal behavior predicted by each method is discussed. The thermal comfort indicators PMV (predicted mean vote) and PPD (predicted percentage of dissatisfied) were calculated for two flats, at ground floor and first floor respectively.     

Real time assessment of the compatibilization of polypropylene/polyamide 6 blends during extrusion

The reactivity of maleic anhydride and acrylic acid polypropylene graft copolymers with amine groups and their effect in the compatibilization of polymer blends was analyzed in real time during the reactive processing of compatilized polypropylene/polyamide 6 (PP/PA6) blends. The presence of compatibilizers in the blend produces a block copolymer PP‐PA6, which stays in the blends interface, lowering the interfacial tension and reducing the PA6 particle size, affecting the light extinction phenomena. The in‐line optical detector is able to indirectly quantify the conversion of the compatibilization reaction of the blends. The signal intensity of the detector increases with the increase of the PA6 content due to the increase in the number of particles. Quantitative off‐line FTIR analyses of the compatibilized blends have shown that the amount of block copolymer formed when polypropylene grafted with acrylic acid (PP‐g‐AA) is used as compatibilizer increases with its content in the blend. There is a good correlation between the in‐line optical measurement and the off‐line amidic bond content formed. Non‐reacted compatibilizers are always present in the reactive blends whose content is proportional to its initial concentration. The PA6 particle size data obtained from scanning electron microscopy analysis showed good correlation with the in‐line measurements. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

An efficient ruthenium-vanadium catalyst for selective hydrogenation of ortho-chloronitrobenzene

An attempt has been made at obtaining a catalyst for hydrogenation of ortho-chloronitrobenzene (o-CNB) to ortho-chloroaniline (o-CAN) which would be both selective and active. Ruthenium has been used as the active phase since it is the most selective of all metals investigated in the above reaction. Catalyst precursors, RuCl₃·3H₂O and NH₄VO₃, were introduced onto an unconventional support – MgF₂ and reduced in hydrogen flow at 673 K. The catalysts obtained revealed unusually high activity and selectivity in the reaction of hydrogenation of o-CNB to o-CAN, both in the gas- and liquid phase. The structural study of the Ru-V/MgF₂ catalyst has shown that its high activity and selectivity were determined by the strong metal–support interactions and ruthenium–VO_x species electron interactions.     

Bending of Layer-by-Layer Films Driven by an External Magnetic Field

We report on optimized architectures containing layer-by-layer (LbL) films of natural rubber latex (NRL), carboxymethyl-chitosan (CMC) and magnetite (Fe₃O₄) nanoparticles (MNPs) deposited on flexible substrates, which could be easily bent by an external magnetic field. The mechanical response depended on the number of deposited layers and was explained semi-quantitatively with a fully atomistic model, where the LbL film was represented as superposing layers of hexagonal graphene-like atomic arrangements deposited on a stiffer substrate. The bending with no direct current or voltage being applied to a supramolecular structure containing biocompatible and antimicrobial materials represents a proof-of-principle experiment that is promising for tissue engineering applications in biomedicine.     

Influence of Activation and the HDS Reaction on the Structure of Magnesium Fluoride-Supported Ru Catalysts Derived from Ruthenium Chloride Hydrate

The effect of water and reductants (CO and H₂) on the decomposition of NO _x stored on BaO/Al₂O₃ at 300 °C has been investigated. Water eliminates the initial rapid total uptake of NO₂ but has little effect on the subsequent formation of nitrates that is accompanied by evolution of NO. Water hinders liberation of NO₂ and NO during temperature-programmed decomposition of stored NO _x . Both CO and H₂ lower the temperatures required for decomposition through reduction of NO₂ to NO and N₂ thus restricting NO₂ readsorption. The rate of reduction is lower with H₂ than with CO.