Plasma-induced grafting of polydimethylsiloxane onto polyurethane surface: Characterization and in vitro assay

Plasma-induced grafting of polydimethylsiloxane (PDMS) onto the surface of polyurethane (PU) film. The virgin, plasma treated, and PDMS grafted PU films were characterized by means of attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, water drop contact angle measurements, and scanning electron microscopy (SEM). The ATR-FTIR spectrogram of the grafted film showed the new characteristic peaks of PDMS. These grafted surfaces exhibited higher hydrophobicity and homogenous morphology. In vitro cell culture study showed that modified surfaces as well as virgin film were compatible with fibroblast cells. The formation of graft polymers combines the biostability of silicone with excellent physical and mechanical properties of PU.     

On the Maximal and Minimal Left Ideals of Certain Banach Algebras on Locally Compact Groups

Let ${L_0^\infty(G)}$ be the Banach space of all essentially bounded measurable functions on a locally compact group G vanishing at infinity. In this paper, we describe maximal and minimal left ideals in the Banach algebra ${L_0^\infty(G)^*}$ equipped with an Arens type product. We also investigate some spectral properties of ${L_0^\infty(G)^*}$ .     

Volumetric and Viscometric Studies of <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-Bis(salicylaldehyde)-1,3-diaminopropane Schiff Base (Salpr) in Ionic Liquid + DMF solutions

The apparent molar volumes and viscosities of N,N′-bis(salicylaldehyde)-1,3-diaminopropane Schiff base (Salpr) have been determined in ionic liquid {1-pentyl-3-methylimidazolium bromide ([PnMIm]Br)} + N,N-dimethylformamide (DMF) solutions at 298.15 K from density and viscosity measurements using a vibrating tube densimeter and übbelohde type viscometer, respectively. These data have been used to calculate standard partial molar volumes, V_f ⁰V_{\phi} ^{0}, transfer partial molar volumes, Δ_tr V ⁰, and viscosity B-coefficients of the solutions. The transfer partial molar volumes are negative, and decrease with increasing the concentration of ionic liquid for all of the investigated solutions. It found that this ionic liquid interacts strongly with the Schiff base (Salpr) and has desolvation effect on the Schiff base molecules.     

The double negation of the intermediate value theorem

In the context of intuitionistic analysis, we consider the set F consisting of all continuous functions ? from [0,1] to R such that ?(0)=0 and ?(1)=1, and the set I₀ consisting of ?’s in F where there exists x∈[0,1] such that . It is well-known that there are weak counterexamples to the intermediate value theorem, and with Brouwer’s continuity principle we have I₀≠F. However, there exists no satisfying answer to . We try to answer to this question by reducing it to a schema (which we call ) about intuitionistic decidability that asserts “there exists an intuitionistically enumerable set that is not intuitionistically decidable”. We also introduce the notion of strong Specker double sequence, and prove that the existence of such a double sequence is equivalent to the existence of a function ?∈F_mon where .     

The study of the weibel electromagnetic instability growth rate in the presence of the body stress

Body stress flow can be expected in the fast ignition imploding of the inertial fusion process that strongly damps small‐scale velocity structures. The Weibel instability is one of the plasma instabilities that require anisotropy in the distribution function. The body stress effect was neglected in the calculation of the Weibel instability growth rate. In this article, the propagation condition of impinging waves and the growing modes of the Weibel instability on the plasma density gradient of the fuel fusion with the body stress flow are investigated. Calculations show that the minimum value of the body stress rate threshold in the linear polarization is about 2.96 times greater than that of the circular polarization. Increasing 10 times of the density gradient and decreasing 2 times of the wavelength in the linear polarization and the circular polarization, respectively, lead to about 1.78 × 10⁶ times increment and 0.019 times decrement in the maximum of the Weibel instability growth rate. Also, the Weibel instability growth rate maximum in the circular polarization is about 10⁷ times greater than that of the linear polarization. The body stress flow and the density gradient tend to stabilize the Weibel instability in the circular polarization and act as a destabilizing source in the linear polarization. Therefore, by increasing steps of the density gradient plasma near the relativistic electron beam‐emitting region, in the circular polarization, the Weibel instability occurs at a higher stress flow.     

Stability of mixed additive-quadratic Jensen type functional equation in non-Archimedean \ell -fuzzy normed spaces

In this papers we prove the generalized Hyers–Ulam–Rassias stability of the following mixed additive-quadratic Jensen functional equation $$\begin{aligned} 2f\left( \frac{x+y}{2}\right) +f\left( \frac{x-y}{2}\right) +f\left( \frac{y-x}{2}\right) =f(x)+f(y) \end{aligned}$$ in non- Archimedean \(\ell \) -fuzzy normed spaces.     

Supertough spontaneously self-healing polymer based on septuple dynamic bonds integrated in one chemical group

The development of spontaneously self-healing materials with excellent mechanical properties remains a formidable challenge despite the extensive interest in such materials. This is because the self-healing and mechanical properties of a material are usually optimized via contradictory routes. The present study demonstrated a supertough spontaneously self-healing polymer,Fe-(2,6-diacetylpyridine dioxime)-urethane-based polyurethane(Fe-PPOU) based on septuple dynamic bonds integrated in one chemical group. A synergistic effect was induced by the presence of multiple dynamic crosslinking points, which comprised the integrated dynamic interactions, and the hidden lengths of the folded polymeric chains in Fe-PPOU. Thus, the mechanical and self-healing properties of the polymer were simultaneously optimized. Fe-PPOU demonstrated the highest reported toughness(139.8 MJ m^-3) among all the room-temperature spontaneously self-healing polymers with a nearly 100% healing rate. Fe-PPOU exhibited instant(30 s) self-healing to reach a strength of 1.6 MPa that was higher than the original strength of numerous recently reported self-healing polymers.     

Quantification of Density-Driven Natural Convection for Dissolution Mechanism in CO<Subscript>2</Subscript> Sequestration

Dissolution of CO₂ into brine causes the density of the mixture to increase. The density gradient induces natural convection in the liquid phase, which is a favorable process of practical interest for CO₂ storage. Correct estimation of the dissolution rate is important because the time scale for dissolution corresponds to the time scale over which free phase CO₂ has a chance to leak out. However, for this estimation, the challenging simulation on the basis of convection–diffusion equation must be done. In this study, pseudo-diffusion coefficient is introduced which accounts for the rate of mass transferring by both convection and diffusion mechanisms. Experimental tests in fluid continuum and porous media were performed to measure the real rate of dissolution of CO₂ into water during the time. The pseudo diffusion coefficient of CO₂ into water was evaluated by the theory of pressure decay and this coefficient is used as a key parameter to quantify the natural convection and its effect on mass transfer of CO₂. For each experiment, fraction of ultimate dissolution is calculated from measured pressure data and the results are compared with predicted values from analytical solution. Measured CO₂ mass transfer rate from experiments are in reasonable agreement with values calculated from diffusion equation performed on the basis of pseudo-diffusion coefficient. It is suggested that solving diffusion equation with pseudo diffusion coefficient herein could be used as a simple and rapid tool to calculate the rate of mass transfer of CO₂ in CCS projects.