Textile applications of commercial photochromic dyes: part8. A statistical investigation of the influence of photochromic dyes on thermoplastic fibres using a UV-irradiation technique

Abstract

This research investigates the influence of the commercial photochromic dye concentration, expressed as a percentage, and polymer type and their interaction on the photocoloration properties of the as-spun and drawn fibres regarding the melt-spinning process. As-spun fibres made of polypropylene, polyethylene and polyester were spun with different percentages of the photochromic dye, drawn, tested and analysed under a factorial experimental design using appropriate experimental and statistical methods. According to the analyses and by using an independent source of ultraviolet irradiation and traditional colour measurement instrumentation of the degree of photocoloration and background colour, the most effective and significant parameter influencing the as-spun fibre’s photocoloration properties are the polymer type; the dye percentage effect was noted in the degree of photocoloration. The effects of the multi-stage hot-drawing process on the photocoloration properties of the drawn polypropylene and polyethylene fibres were characterised and statistically modelled. The dyed fibres showed reversible photochromism, developing pronounced colours from weak background colours on irradiation with ultraviolet light and returning to their original state when the ultraviolet light source was removed. The dye percentage positively affects the photocoloration of the as-spun and drawn polypropylene and polyethylene fibres. A new forecasting data source was achieved to optimise the selection of the polymer and the dye percentage and to specify the direction of increasing or decreasing of the significant process parameters. Utilising the elastic properties of manufactured fibres, they could be used in the development of chromic textiles for creative design, functional or smart purposes.     

PCR amplification of 18S rRNA,single cell protein production and fatty acid evaluation of some naturally isolated microalgae

Microalgae were isolated during a screening program from soil samples collected from paddy-fields of Fars province, south of Iran. The protein content was assayed by the Kochert method. Total genomic DNA were isolated and used for PCR amplification of the 18S rRNA gene. The sequences were determined for 12 species of microalgae. Some bioinformatic tools were used for more investigation on these biologic data. Total lipids from five microalgal species were extracted and used for determination of different types of fatty acids by gas chromatography–mass spectrometry method. In our experiments the green algae yielded a maximum protein of about 42% ± 1.64. The DNA sequences were published in the NCBI under specific accession numbers. The composition of fatty acids was mainly, myristic acid, palmitic acid, oleic acid, α-linolenic acid, and γ-linolenic acid.     

Numerical Modeling of Insulating Particles Trajectories in Roll-type Corona-Electrostatic Separators

The trajectories of the insulating particles in roll-type corona-electrostatic separators depend on the configuration of the electrode system, the applied high voltage, the roll speed, the size of the particles and the relative humidity of the ambient air. The aim of this work was to point out how numerical modeling can be of use in the study of the effects of these factors. Particle charging is modeled using the Pauthenier?s equation for spheres in uniform electric field. The equation of particle discharging was obtained after an experimental study of the surface potential decay of a granular layer of insulating material in contact with an electrode. The trajectories are computed based on the balance equation of the electrical and mechanical forces that act on such charged particles. The numerical results are in good agreement with the experimental findings.     

A comparison of residual stresses in built-up steel beams using hole-drilling method

Residual stresses have a significant effect on the stability resistance of metal building systems. An experimental program was conducted to measure these stresses in built-up steel beams using incremental hole-drilling method. The experimental results reveal that the predicted residual stress type of pattern for built-up I-sections with fillet welds on one side of the web is not the same as the pattern of residual stresses in built-up I-sections with fillet welds on both sides of the web. This paper was recommended for publication in revised form by Associate Editor Youngseog Lee Mohammed Al-Nawafleh received his B.S. and M.S degrees in Mechanical Engineering from Leningrad Institute of Textile and Light Industry, in 1989. He then received his Ph.D. degree from Sankt-Petersburg State University of Technology and Design, Russia in 1993. Dr. Nawafleh (1997–2005) was a Professor at the Department of Mechanical Engineering at Al-Balqa’ Applied University in Jordan. From 2005 to 2008 he was a Professor at the Department of Mechanical Engineering at Tafila Technical University, and currently he is a Professor at the Department of Civil Engineering at Al-Hussein Bin Talal University, Jordan.     

Influence of hydrogen content on the tensile properties and fracture of austenitic stainless steel welds

This study evaluates the effects of internal hydrogen on the tensile properties and fracture behaviours of a tungsten inert gas (TIG) weld and an autogenous electron beam (EB) weld of a 304L steel tube. Tensile specimens were thermally charged with hydrogen gas to achieve three different levels of hydrogen in these materials. Metallographic examination revealed that the TIG weld contained skeletal and lathy ferrite, whilst the EB weld displayed a fine dispersion of skeletal and vermicular ferrite. Average volume fractions of ferrite in these welds were 8% and 1%, respectively. The tensile data showed that hydrogen increased the yield and tensile strength, and caused a significant loss in ductility, particularly for the TIG weld. Fractographic analysis revealed that hydrogen induced a change in the fracture mode of the welds and promoted cracking at or near ferrite–austenite interfaces. The TIG weld was found to exhibit a higher susceptibility to hydrogen embrittlement than that of the EB and base metal.     

A GENETIC ALGORITHM FOR THE SHAPE OPTIMIZATION OF PARTS SUBJECTED TO THERMAL LOADING

In many technical situations, the optimization of the mechanical behavior of structures proceeds from the search for the ideal shape satisfying thermal, mechanical, technological, and geometrical constraints. In this article, the shape optimization of mono- and two-dimensional structures is handled by means of a new genetic algorithm (GA). The method is in general well suited to the resolution of nonconstrained optimization problems: The algorithm presented here has been modified by taking into account the imposed design constraints in the selection of the "individuals" belonging to a given population. The crossover operation between individuals and the mutation process in their original forms are applied to derive the optimal shape of parts subjected to thermal loadings. The algorithm exhibits a good convergence toward the optimal solution and the numerical results of its application show a good numerical accuracy.     

Sonochemical Synthesis and Characterization of A Nano-Rod Lead(II) Supramolecular, Three Dimensional Coordination Compound: New Precursor to Produce Pure Phase Nano-Sized Lead(II) Oxide

Nanorods of a lead(II) supramolecular three-dimensional (3D) coordination compound, [Pb(tfpb)₂]_n (1) (Htfpb?=?4,4,4-trifluoro-1-phenyl-1,3-butanedione), was prepared by the sonochemical method. The new nano-structure was characterized by scanning electron microscopy, X-ray powder diffraction, elemental analyses and IR spectroscopy. A single-crystal structure of the compound showed that the coordination number of Pb(II) is eight with six O-donor atoms from the tfpb ligand and two F-donors from anionic ligands. The 3D supramolecular structure of 1 is realized by weak directional C–F···F–C and π–π stacking interactions. After calcination of nano-sized 1 at 500?°C, pure phase nano-sized lead(II) oxide is produced.     

Solvothermal Synthesis of a Nano-sized Aza-aromatic Base Adduct of a Cadmium(II) 4,4-Difluoro-1-phenyl-1,3-butandionate Coordination Compound

A new nano-structured cadmium(II) coordination compound, [Cd(phen)(dfpb)₂] (1) (phen?=?1,10-phenanthroline, dfpb?=?4,4-difluoro-1-phenyl-1,3-butandion), was synthesized by a solvothermal method and produced a coordination polymer in the nano-size range. The new nanostructure was characterized by scanning electron microscopy, X-ray powder diffraction elemental analysis and IR spectroscopy. Compound 1 was structurally characterised by single crystal X-ray diffraction. The single crystal structure shows a coordination number for the Cd ion of six with two N-donor atoms from the phen ligand and four O-donors from the two dfpb moieties. Self-assembly occurs by CH····F–C and π–π stacking interactions. The supramolecular features in these complexes are controlled by weak directional intermolecular interactions.     

Principal component based diffeomorphic surface mapping

We present a new diffeomorphic surface mapping algorithm under the framework of large deformation diffeomorphic metric mapping (LDDMM). Unlike existing LDDMM approaches, this new algorithm reduces the complexity of the estimation of diffeomorphic transformations by incorporating a shape prior in which a nonlinear diffeomorphic shape space is represented by a linear space of initial momenta of diffeomorphic geodesic flows from a fixed template. In addition, for the first time, the diffeomorphic mapping is formulated within a decision-theoretic scheme based on Bayesian modeling in which an empirical shape prior is characterized by a low dimensional Gaussian distribution on initial momentum. This is achieved using principal component analysis (PCA) to construct the eigenspace of the initial momentum. A likelihood function is formulated as the conditional probability of observing surfaces given any particular value of the initial momentum, which is modeled as a random field of vector-valued measures characterizing the geometry of surfaces. We define the diffeomorphic mapping as a problem that maximizes a posterior distribution of the initial momentum given observable surfaces over the eigenspace of the initial momentum. We demonstrate the stability of the initial momentum eigenspace when altering training samples using a bootstrapping method. We then validate the mapping accuracy and show robustness to outliers whose shape variation is not incorporated into the shape prior.     

A Trace-Time Framework for Prediction of Elevation Angle Over Land Mobile LEO Satellites Networks

Elevation angle is one of the most significant parameters of land mobile satellite channels, subject to rapid variations in the case of Low Earth Orbit (LEO) satellite systems. In this paper a novel trace-based framework is proposed and analyzed which is capable of predicting elevation angle as a function of time during satellite visibility window. Trace-time based modeling makes the framework practical for real-time evaluation of elevation angle and its alteration incurred by communication links in LEO satellite systems. The proposed method is particularly suitable for development of communication channel models and services in mobile LEO satellite networks where path variability is of great importance.