Radiation grafting to poly(ethylene terephthalate) fibres

Polyethylene terephthalate (PET) monofilaments were grafted with styrene in methylene chloride solution using both the mutual and preirradiation methods. Good yields were obtained, the grafted fibres were dissolved and the graft copolymer and both homopolymers separated by various techniques. The graft copolymers were hydrolysed with potassium hydroxide in benzyl alcohol to destroy the PET backbone. The molecular weights were determined by osmometry. The G values of grafted side chains were 0.57 and 0.10 per 100 eV for the mutual and preirradiation methods, respectively. The corresponding fractions of PET grafted were 0.24 and 0.11. Less than 4% homopolymer was produced by either method. The yields contrast with radical yields measured by e.s.r. of only 0.025. It is suggested that the high grafting yields are due to the methylene chloride facilitating the accessibility of the monomer to the active sites created by the radiation rather than by the increased yields of radicals by chain transfer. Chlorine, for example, did not lead to increased yields even in the presence of methylene chloride. Presumably, in the mutual grafting system, radicals are available for grafting, which are too labile to be detected by e.s.r. In the case of the preirradiation method, the yields are also higher than the radical yields. This may be due to a regenerative chain transfer mechanism.     

Logic of Proofs and Labels with a Complete Set of Operations

We develop a framework in which operations on proofs can bespecified and studied. Proofs are treated as structures builtfrom atomic proofs and references by means of computable operations. Our approach extends the ideas of Logic of Proofs (Artemov,1995, Bull. Symb. Logic, 7, 1–36) in which the proof predicate‘t is a proof of F ’ is incorporated into the propositionallanguage. We introduce an additional storage predicate ‘xis a label for F ’ (Yavorskaya, 2005, J. Logic Comput.,15, 517–537). In this article which is essentially a continuation of Yavorskaya'swork, we study a natural example of a logic with operationson proofs and labels. This logic is decidable and complete with respect to its intended semantics. is capable to internalizeits own proofs, and operations of suffice to realize all operations specified in the languagewith proofs and labels.     

Experimental investigation on adaptive robust controller designs applied to a free-floating space manipulator

This paper aims to formulate and investigate the application of various nonlinear H_∞ control methods to a free-floating space manipulator subject to parametric uncertainties and external disturbances. From a tutorial perspective, a model-based approach and adaptive procedures based on linear parametrization, neural networks and fuzzy systems are covered by this work. A comparative study is conducted based on experimental implementations performed with an actual underactuated fixed-base planar manipulator which is, following the DEM concept, dynamically equivalent to a free-floating space manipulator.     

Joint distribution of the number of vertices with given different outdegrees in Galton–Watson forest

A Galton–Watson forest consisting of N roots (or trees) and n   non-root vertices is considered. We study limit distributions of the number of vertices of a given outdegree in such a forest. In this work joint distribution of the number of vertices with the given different outdegrees _r1$r_1$ and _r2$r_2$ is considered. A local limit theorem for this characteristic is proved.     

Alternative Local Melting-Solidification of Suspended Nanoparticles for Heterostructure Formation Enabled by Pulsed Laser Irradiation

Phase formation by pulsed laser irradiation of suspended nanoparticles has recently been introduced as a promising synthesis technique for heterostructures. The main challenge still lingers regarding the exact mechanism of particle formation due to the non-equilibrium kinetic by-products resulting from the localized alternative, fast, high-temperature nature of the process. Here, the authors analyze the bond breaking/formation of copper or copper (II) interfaces with ethanol during the absorption of pulses for Cu-CuO-Cu₂O formation applicable as an electrocatalyst in ethanol oxidation fuel cells. This study includes but is not limited to, a comprehensive discussion of the interaction between nano-laser pulses and suspension for practical control of the synthesis process. The observed exponential and logarithmic changes in the content of heterostructures for the CuO-ethanol and Cu-ethanol samples irradiated with different fluences are interpreted as the dominant role of physical and chemical reactions, respectively, during the pulsed laser irradiation of suspensions synthesis. It is also shown that the local interface between dissociated ethanol and the molten sphere is responsible for the oxidative/reductive interactions resulting in the formation of catalytic-augmented Cu³⁺ by-product, thanks to the reactive bond force field molecular dynamics studies confirmed by ab-initio calculations and experimental observations.     

Surface characteristics of polypropylene fibrous materials modified with ultradisperse polytetrafluoroethylene

This paper is devoted to analysis of the surface properties of polypropylene fibrous materials modified during molding via introduction of polytetrafluoroethylene ultradisperse powder into polypropylene melt. It is shown that the modification changes not only the bulk, but also surface, characteristics of the fibrous material. Evidence is provided of the presence of polytetrafluoroethylene particles on the fiber surface, and its content is determined. The effect of fiber modification on its tangential resistance coefficient and its amenability to processing is considered. The effect of ultradisperse polytetrafluoroethylene introduced into polypropylene melt on the hydrophobicity of the modified fibrous material is analyzed in detail.     

Synthesis of protein nano-conjugates for cancer therapy

A eukaryotic cell contains thousands of proteins that regulate its cellular function; delivering functional proteins into cells to rectify cellular functions holds great promise for treatment of various diseases, especially cancers. In this context, ribonuclease (RNase), an enzyme that breaks down ribonucleic acid (RNA), has great potential for cancer therapy. However, its therapeutic application is hampered by poor intracellular delivery efficiency and inhibition by ubiquitous intracellular RNase inhibitors. In this work, by designing and synthesizing RNase nano-conjugates by in situ atom transfer radical polymerization (ATRP), we demonstrate a simple solution to address both challenges. Compared with native RNase, nano-conjugates exhibit significantly enhanced intracellular delivery efficiency, inhibitor resistance, and a near five-fold increase in cytotoxicity. This work provides a novel platform for delivery of therapeutic proteins for cancer therapy and other applications.     

Interacting Explicit Evidence Systems

Logic of proofs , introduced by S. Artemov, originally designed for describing properties of formal proofs, now became a basis for the theory of knowledge with justification (cf. S. Artemov, Evidence-based common knowledge, Technical report TR–2004018, CUNY Ph.D. Program in Computer Science, 2005). So far, in epistemic systems with justification the corresponding “evidence part”, even for multi-agent systems, consisted of a single explicit evidence logic. In this paper we introduce logics describing two interacting explicit evidence systems. We find an appropriate formalization of the intended semantics and prove the completeness of these logics with respect to both symbolic and arithmetical models. Also, we find the forgetful projections for the two-agent justification logics which are extensions of the bimodal logic .     

Replication of empirical studies in software engineering research: a systematic mapping study

In this article, we present a systematic mapping study of replications in software engineering. The goal is to plot the landscape of current published replications of empirical studies in software engineering research. We applied the systematic review method to search and select published articles, and to extract and synthesize data from the selected articles that reported replications. Our search retrieved more than 16,000 articles, from which we selected 96 articles, reporting 133 replications performed between 1994 and 2010, of 72 original studies. Nearly 70 % of the replications were published after 2004 and 70 % of these studies were internal replications. The topics of software requirements, software construction, and software quality concentrated over 55 % of the replications, while software design, configuration management, and software tools and methods were the topics with the smallest number of replications. We conclude that the number of replications has grown in the last few years, but the absolute number of replications is still small, in particular considering the breadth of topics in software engineering. We still need incentives to perform external replications, better standards to report empirical studies and their replications, and collaborative research agendas that could speed up development and publication of replications.