Processingâ Dependent Microstructure of AgClâ CsAgCl2 Eutectic Photonic Crystals

Directional solidification of a eutectic melt allows control over the resultant eutectic microstructure, which in turn impacts both the mechanical and optical properties of the material. These selfâ organized phaseâ separated eutectic materials can be tuned to have periodicities from tens of micrometers down to nanometers. Furthermore, the two phases possess differences in their refractive index leading to interesting optical properties that can be tailored within the visible to infrared wavelength regime. It is found the binary salt eutectic AgClâ CsAgCl2 system forms a rod microstructure with sample draw rates up to 0.2 mm sâ 1 which transitions to a lamellar microstructure at draw rates greater than 0.36 mm sâ 1. Heatâ transfer simulations reveal a draw rateâ dependent direction of motion of the solidification front, which for a range of draw rates requires nucleation of the minority solid phase at the sample wall. Phaseâ field modeling indicates that the initial eutectic structure at the sample boundary, either rod or lamellar, dictates the bulk eutectic morphology. These samples contain submicrometer periodicities which coupled with their optical transparency results in them exhibiting draw rateâ dependent nearâ IR reflectance peaks consistent with stop bands for 2D hexagonal (rod) and 1D planar (lamellar) photonic crystals.The eutectic composition of the molten salts AgCl and CsCl exhibits a microstructural transition from rod to lamellar upon varying the draw rates controlled by directional solidification. This transition is dominated by the initial formation at the surface of either the rod or lamellar structure. The resultant eutectic microstructures have optical properties consistent with their being 2D and 1D photonic crystals.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145412/1/adom201701316.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145412/2/adom201701316_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145412/3/adom201701316-sup-0001-S1.pd

On temperature- and space-dimension dependent matter agglomeration in a mature growing stage

Model matter agglomerations, with temperature as leading control parameter, have been considered, and some of their characteristics have been studied. The primary interest has been focused on the grain volume fluctuations, the magnitude of which readily differentiates between two commonly encountered types of matter agglomeration/aggregation processes, observed roughly for high- and low-density matter organizations. The two distinguished types of matter arrangements have been described through the (entropic) potential driving system. The impact of the potential type on the character of matter agglomeration has been studied, preferentially for (low density) matter agglomeration for which a logarithmic measure of its speed has been proposed. A common diffusion as well as mechanical relaxation picture, emerging during the mature growing stage, has been drawn using a phenomenological line of argumentation. Applications, mostly towards obtaining soft agglomerates of so-called jammed materials, have been mentioned

Ionic liquids at electrified interfaces

Until recently, “room-temperature” (<100–150 °C) liquid-state electrochemistry was mostly electrochemistry of diluted electrolytes(1)–(4) where dissolved salt ions were surrounded by a considerable amount of solvent molecules. Highly concentrated liquid electrolytes were mostly considered in the narrow (albeit important) niche of high-temperature electrochemistry of molten inorganic salts(5-9) and in the even narrower niche of “first-generation” room temperature ionic liquids, RTILs (such as chloro-aluminates and alkylammonium nitrates).(10-14) The situation has changed dramatically in the 2000s after the discovery of new moisture- and temperature-stable RTILs.(15, 16) These days, the “later generation” RTILs attracted wide attention within the electrochemical community.(17-31) Indeed, RTILs, as a class of compounds, possess a unique combination of properties (high charge density, electrochemical stability, low/negligible volatility, tunable polarity, etc.) that make them very attractive substances from fundamental and application points of view.(32-38) Most importantly, they can mix with each other in “cocktails” of one’s choice to acquire the desired properties (e.g., wider temperature range of the liquid phase(39, 40)) and can serve as almost “universal” solvents.(37, 41, 42) It is worth noting here one of the advantages of RTILs as compared to their high-temperature molten salt (HTMS)(43) “sister-systems”.(44) In RTILs the dissolved molecules are not imbedded in a harsh high temperature environment which could be destructive for many classes of fragile (organic) molecules

Wpływ lizozymu na zakres proteolitycznej fazy podpuszczkowego krzepnięcia mleka

In the present studies, the influence of lysozyme on the extent of rennet proteolysis of milk, of x-casein solution and casein micelles, suspended in artificial serum of milk, was examined. The obtained results showed that lysozyme did not affect signicicantly the rennet hydrolysis of casein. At the highest level of fysozyme addition applied (2.0 mg/cm³), a certain lowering in the amount of glycopeptide released from casein by rennet, was observed; it makes it possible to suppose that lysozyme decreased the quantity of hydrolized casein indispensable for a coagulation of this protein.W pracy prześledzono wpływ dodatku lizozymu (0,5; 1,0; i 2,0 mg/cm³) na proteolizę podpuszczkową mleka. Doświadczenie wykonano w 3 seriach, w których substrat do badań stanowiły kolejno: mleko regenerowane z odtłuszczonego proszku mlecznego, 1 % roztwór x-kazeiny oraz roztwór miceli kazeinowych wyizolowanych z mleka przez wirowanie. Miarą stopnia proteolizy było oznaczenie przyrostu ilości związków azotowych rozpuszczalnych w 12% KTO oraz ilości N-acetylo-D-galaktozaminy (NAcGal) związanej z tą frakcją po inkubacji prób z podpuszczką. Wyniki doświadczeń przeprowadzonych na mleku nie dały jednoznacznej odpowiedzi co do wpływu lizozymu na proces proteolizy (tab. 1 i 2). Nie stwierdzono również istotnych różnic w ilości uwalnianych związków azotowych pomiędzy próbkami z lizozymem i próbkami kontrolnymi, w doświadczeniach przeprowadzonych na roztworze x-kazeiny (tab. 3 i 4) oraz na micelach kazeinowych zdyspergowanych w sztucznym serum mleka (tab. 5, 6). Na podstawie uzyskanych w pracy wyników można stwierdzić, że lizozym nie wpływał w istotny sposób na hydrolizę kazeiny przez podpuszczkę. Zaobserwowane obniżenie poziomu uwalnianych glikopeptydów w próbkach z wyższym dodatkiem lizozymu (2 mg/cm³) potwierdza wysuwaną przez niektórych autorów hipotezę, że lizozym obniża jedynie niezbędną ilość uwalnianego z kazeiny glikomakropeptydu, konieczną do spowodowania koagulacji tego białka pod wpływem podpuszczki

Electrochemical studies of heterogeneous reduction of tetracyanoquinodimethane in polymer electrolytes using ac impedance at an ultramicroelectrode

Electrochemical studies of the TCNQ(0)/TCNQ(-) couple have been carried out using ac impedance spectroscopy and cyclic voltammetry at platinum ultramicroelectrodes (UME). Liquid poly(ethylene oxide) (PEO) CH3-O-(CH2-CH2-O)(4)-CH3 has been used as the solvent with different concentrations of the TCNQ(0)/TCNQ(-) couple and LiClO4 as the supporting electrolyte. On the basis of the ac impedance results at the UME it has been found that the double layer capacitance and standard heterogeneous rate constant are independent of the presence of electroactive species and supporting electrolyte concentrations, indicating that adsorption of electroactive species onto the electrode is not significant. The standard heterogeneous rate constant k(s) was found to be 0.109 +/-0.005 cm s(-1). A similar value of k(s)=0.094 cm s(-1) was obtained for the second reduction step TCNQ(-)/TCNQ(2-). Diffusion coefficients of both TCNQ and TCNQ(-) are equal, D=1.0x10(-6) cm(2) s(-1) for a 0.5 M LiClO4 solution. Higher diffusion coefficients are obtained in less concentrated supporting electrolyte. Comparison is made between these results and those reported previously for PEO-400 HO-(CH3CH2O)(8)-OH.(1) The different end groups significantly influence the viscosity and hence k(s).</p