Interaction of nanoparticles with lipid membrane

A nanoscale range of surface feature curvatures where lipid membranes lose integrity and form pores has been found experimentally. The pores were experimentally observed in the l-alpha-dimyristoyl phosphatidylcholine membrane around 1.2-22 nm polar nanoparticles deposited on mica surface. Lipid bilayer envelops or closely follows surface features with the curvatures outside of that region. This finding provides essential information for the understanding of nanoparticle-lipid membrane interaction, cytotoxicity, preparation of biomolecular templates and supported lipid membranes on rough and patterned surfaces.     

Investigation of path dependence in commercial lithium-ion cells chosen for plug-in hybrid vehicle duty cycle protocols

There is a growing need to explore path dependence of aging processes in batteries developed for long-term usage, such as lithium-ion cells used in hybrid electric vehicle (HEV) or plug-in hybrid vehicle (PHEV) applications that may then be “retired” to be utilized in grid applications. To better understand the foremost influences on path dependence in the PHEV context, this work aims to bridge the gap between ideal laboratory test conditions and PHEV field conditions by isolating the predominant aging factors in PHEV service, which would include, for example, the nature and frequency of duty cycles, as well as the frequency and severity of thermal cycles. These factors are studied in controlled and repeatable laboratory conditions to facilitate mechanistic evaluation of aging processes. This work is a collaboration between Idaho National Laboratory (INL) and the Hawaii Natural Energy Institute (HNEI). Commercial lithium-ion cells of the Sanyo Y type (18650 configuration) are used in this work covering two initial independent studies of path dependence issues. The first study considers how the magnitude of power pulses and charging rates affect the aging rate, while the second seeks to answer whether thermal cycling has an accelerating effect on cell aging. While this work is in early stages of testing, initial data trends show that cell aging is indeed accelerated under conditions of high discharge pulse power, higher charge rates, and thermal cycling. Such information is useful in developing accurate predictive models for estimating end-of-life conditions.     

Polymer brushes as active nanolayers for tunable bacteria adhesion

Bacterial biofilm formation on implant surfaces is a frequent reason for the failure of many biomedical devices. Polymer brushes, thin nanolayers constituted of densely grafted macromolecules, are promising candidates to use in many biomedical applications to control attachment of bacteria to a surface. In this work five different polymer brushes were synthesized and tested with respect to their ability to regulate Staphylococcus aureus adhesion. Namely, two mixed brushes [consisting of poly(ethylene glycol) and a positively charged polymers, poly(2-vynil pyridine) or quartenized poly(2-vynil pyridine)] are investigated along with one-component brushes of the respective polymers. Bacterial adhesion was regulated over two orders of magnitude via altering the polymer brush composition.     

Optical and structural properties of Nb2O5–SiO2 mixtures in thin films

Mixed material thin films are used in gradient index optical systems as their refractive index can be tailored to meet requirements. For the system to meet the optical performance requirements, it is necessary to relate the refractive index profile of the design to the volume fraction of the components of the mixture. Here we report that for electron-beam co-deposited Nb₂O₅–SiO₂ mixtures, the most appropriate effective medium theory is Lorentz–Lorenz theory. The optical properties of a mixture are related to the structure of the composite. The structural properties of the mixtures studied justify the appropriateness of Lorentz–Lorenz theory for this kind of effective medium.     

Formation of coatings with tailored properties on polyperoxide-modified polymeric surfaces

Modification (peroxidation) of polymer surfaces, polypropylene, polyethylene, polyethylene terephthalate, nylon 6-6, poly(phenylene oxide), and ethylene–propylene copolymer were affected by the surface grafting of functional polyperoxides (FPPs) such as poly(5-tert-butylperoxy-5-methyl-1-hexene-3-yne-co-octylmethacrylate) (VEP-co-OMA), poly{N-[(tert-butylperoxy)-methyl]acrylamide-co-octyl methacrylate} (PO-co-OMA), and poly(tert-butylperoxy-methacrylate-co-octyl methacrylate) (PEst-co-OMA). The degree of surface modification was shown to be determined primarily by the structure of the polymer substrate. Using a peroxidized surface as an initiator of grafted copolymerization enabled the grafting of functional monomers (acrylic acid, acrylamide, 4-vinylpyridine, and hydroxyethyl methacrylate) and polysaccharides (heparin, dextran, etc.) and thereby imparted adhesive, antibacterial, haemocompatible properties to the polymer surface.     

Classification of Fine Particles Using the Hydrodynamic Forces in the Boundary Layer of a Membrane

The wet classification of particles < 10 μm is a complex process that has been researched for many years. In this study, the usage of a modified cross‐flow filtration process as a classification process was investigated. With this process, particles in a fine micrometer range can be separated from suspensions. The upper particle size is dependent on hydrodynamic forces. The experimental results were compared with different hydrodynamic force models to predict upper size. The influence of the permeate flux and the particle concentration in the feed on the upper particle size is studied.     

Hybrid automata: from verification to implementation

International Journal on Software Tools for Technology Transfer - Hybrid automata are an important formalism for modeling dynamical systems exhibiting mixed discrete–continuous behavior such...     

Die Entwicklung der Verfahrenstechnik an der TU Kaiserslautern

In 1970 the twin university of Kaiserslautern-Trier was founded, from which the two independent universities of Trier and Kaiserslautern emerged in 1975. In 2003, in order to emphasize the focus of the University of Kaiserslautern in engineering, it was renamed to äTechnical University of Kaiserslauternä. In the 50 years of its existence, the development and further development of process engineering was one of the focal points of the mechanical and process engineering department. The article illuminates this path of development and presents the then and current research areas of the four process engineering chairs of the TU Kaiserslautern.     

Multilayer optics for the EUV and soft X-rays

1Introduction Engineersandscientistsinfieldsasdiverse asmicrolithographyandspaceastronomyhavea commonneedtouse“light”rangingfromEUV tothesoftX rayregion.Theextremeultraviolet andsoftX rayspectralregionliebetweentheul travioletandthehardX rayregionsoftheelec tromagneticspectrum.Inspiteofthesmooth transitionsbetweenthespectralsubdivisionsit’s worthtodefineroughlytheirapproximatebor ders[1]:extremeultravioletEUV～50nmto～5nm～25eVto～250eV,softX rayregion～5nmto～0.2nm～250eVto～6keV.The…     

D’Alembert sums for a vibrating bar with viscous ends

We describe a new method for finding analytic solutions to some initial-boundary problems for partial differential equations with constant coefficients. The method is based on expanding the denominator of the Laplace-transformed Green’s function of the problem into a convergent geometric series. If the denominator is a linear combination of exponents with real powers, then one obtains a closed-form solution as a sum with a finite but time-dependent number of terms. We call it a d’Alembert sum. This representation is computationally most effective for small evolution times, but it remains valid even when the system of eigenmodes is incomplete and the eigenmode expansion is unavailable. Moreover, it simplifies in such cases. In vibration problems d’Alembert sums represent superpositions of original and partially reflected traveling waves. They generalize the d’Alembert type formulas for the wave equation and reduce to them when original waves can undergo only finitely many reflections in the entire course of evolution. The method is applied to vibrations of a bar with viscous ends and an internal damper. The results are illustrated by computer simulations and comparisons to modal and finite-element method (FEM) solutions.