Use of a novel initiator for synthesis of amino-end functionalized polystyrene (NH2-PS) by atom transfer radical polymerization

Here we report a versatile new method for end-functionalizing polystyrene. In order to produce polystyrene with an amino end group, 2-(3-bromo-3-phenylpropyl)isoindoline-1,3-dione was synthesized and used as a novel initiator for ATRP. After ATRP polymerization, tri-n-butyltin hydride ((n-Bu)₃SnH) reductively replace existing halogens on polymer chains by hydrogen. Finally, the phthaloyl groups on polymer backbone were cleaved by treatment with hydrazine yielding amino terminated polystyrene. A polymer with M _n ≈ 10,350 and M _w/M _n = 1.17 was obtained. Therefore, this method allows the preparation of amino end functionalized polystyrene of narrow polydispersity with complete degree of functionalization.     

Phenol Removal from Aqueous Solutions by a Novel Industrial Solvent

This article presents a useful method for the removal of phenolic contaminant from water and wastewaters by a novel industrial solvent using liquid-liquid extraction method. For this purpose, a paraffinic-based solvent (Iso-kerosene) was used. The selected ranges for the parameters were 20–50°C for temperature, 100–500 (mg/L) for phenol concentration, and, 1–6 for aqueous feed pH. In each experiment run, the percentage of extraction was calculated. The percentage of extraction was measured to be in the range of 15–70%. The best percentage of extraction was obtained under the conditions of 100 (mg/L), 50°C, and pH = 6. The results showed that the extraction efficiencies are extremely sensitive to temperature. The ANOVA analysis of the results showed the degree of importance of the parameters and their contribution in the final extraction efficiency as extraction temperature, pH of the feed solution, and feed concentration, with a contribution of 73.47, 24.15, and 0.7, respectively. The contribution of experimental error and F ratios also demonstrated the accuracy of the results.     

The Effect of Cooling Rate on Grain Orientation and Misorientation Microstructure of SAC105 Solder Joints Before and After Impact Drop Tests

The effect of different cooling rates on as-assembled Sn1.0Ag0.5Cu (wt.%) solder joints was investigated by using orientation imaging microscopy to characterize evolution of the microstructure and orientation distribution on test samples before and after shock testing. Evolution of the microstructure of joints located near the corners after shock testing differed substantially for samples cooled at different rates after fabrication. After shock and impact testing, much recrystallization was observed for the rapidly cooled samples; this led to polycrystalline microstructures that were effective in absorbing impact energy, by incorporating a growing crack into the recrystallized tin microstructure rather than the lower-energy intermetallic interface, and thus prolonging life. The slowly cooled samples contained large amounts of (301)[ \( \overline{ 1} \) 03] mechanical twins, which also led to an increased number of interfaces that were effective in absorbing energy. The smallest amount of new interface generation after shock testing occurred in the normal cooling rate microstructures, which had the shortest life. Analysis of the crack-propagation paths associated with different cooling rates indicates that development of interfaces from either twinning or polycrystalline microstructure favors crack propagation through the solder rather than the intermetallic layer interface, which toughens the joint.     

A game theoretical study of cooperative advertising in a single-manufacturer-two-retailers supply chain

In the high-speed milling process of large end milling cutter, the stress of cutter caused by centrifugal force accounts for a large proportion of the total stress of the cutter and has a great influence on the milling process. In this paper, an end milling cutter with a diameter of 2,800 mm used on large and high-speed aluminum blank milling machine tools is taken as a research object, and the equations of internal stress caused by centrifugal force have been derived by using analytic method. On this basis, the factors affecting the internal stress were analyzed. Furthermore, the analytic results and the finite element analysis results were compared in order to confirm their correctness. Finally, according to the results of stress analysis, structure topology optimization design for large end milling cutter was carried out in order to reduce the weight and centrifugal force of the cutter.     

Extraction of Gold (III) Ions from Aqueous Solutions Using Polyamine Type Surfactant Liquid Membrane

Experimental results of extraction of gold (III) ions from aqueous solutions by a polyamine type liquid membrane are presented. The effects of various parameters such as concentration of gold ions in the external phase, concentration of carrier, concentration of the internal phase reagents, pH of the external phase and the speed of agitation on the extraction rate were studied. The results show that by proper selection of the extraction conditions, nearly all of the Au (III) ions present in a highly concentrated feed solution was extracted within a few minutes.     

Sustained delivery of olanzapine from sunflower oil‐based polyol‐urethane nanoparticles synthesised through a cyclic carbonate ring‐opening reaction

The forefront horizon of biomedical investigations in recent decades is parcelling‐up and delivery of drugs to achieve controlled/targeted release. In this regard, developing green‐based delivery systems for a spatiotemporal controlling therapeutic agent have drawn a lot of attention. A facile route based on cyclic carbonate ring‐opening reaction has been utilised to synthesise a bio‐based polyol‐containing urethane bond [polyol‐urethane (POU)] as a nanoparticulate drug delivery system of olanzapine in order to enhance its bioavailability. After characterisation, the nanoparticles were also estimated for in vitro release, toxicity, and pharmacokinetic studies. As olanzapine has shown poor bioavailability and permeability in the brain, the sustained release of olanzapine from the designed carriers could enhance pharmacokinetic effectiveness. POU in the aqueous solution formed micelles with a hydrophobic core and embedded olanzapine under the influence of its hydrophobic nature. Drug release from the nanoparticles (90 ± 0.43 nm in diameter) indicated a specific pattern with initial burst release, and then a sustained release behaviour (82 ± 3% after 168 h), by the Higuchi‐based release mechanism. Pharmacokinetics assessments of POU‐olanzapine nanoparticles were carried in male Wistar rats through intravenous administration. The obtained results paved a way to introduce the POU as an efficient platform to enhance the bioavailability of olanzapine in therapeutic methods.Inspec keywords: hydrophobicity, nanomedicine, nanofabrication, nanoparticles, drug delivery systems, biomedical materials, polymers, brainOther keywords: cyclic carbonate ring‐opening reaction, nanoparticulate drug delivery system, bioavailability, drug release, initial burst release, Higuchi‐based release mechanism, POU‐olanzapine nanoparticles, sunflower oil‐based polyol‐urethane nanoparticles, forefront horizon, biomedical investigations, green‐based delivery systems, spatiotemporal controlling therapeutic agent, bio‐based polyol‐containing urethane bond, polyol‐urethane, toxicity, pharmacokinetic studies, olanzapine, aqueous solution, micelles, hydrophobic core, Pharmacokinetics, male Wistar rats, brain     

A new method of producing high strength oil palm shell lightweight concrete

This paper presents a new method to produce high strength lightweight aggregate concrete (HSLWAC) using an agricultural solid waste, namely oil palm shell (OPS). This method is based on crushing large old OPS. Crushed OPS are hard and have a strong physical bond with hydrated cement paste. The 28 and 56 days compressive strength achieved in this study were about 53 and 56 MPa, respectively. Furthermore, it was observed that it was possible to produce grade 30 OPS concrete without the addition of any cementitious materials. Compared to previous studies, significantly lower cement content was used to produce this grade of concrete. Unlike OPS concrete incorporating uncrushed OPS aggregate, this study found that there is a strong correlation between the short term and 28-day compressive strength.     

Ink‐Free Reversible Optical Writing in Monolayers by Polymerization of a Trifunctional Monomer: Toward Rewritable “Molecular Paper”

A Langmuir–Blodgett film consisting of a dense array of trifunctional monomers bearing three 1,8‐diazaanthracene units is polymerized at an air/water interface or after transfer on solid substrates. The transfer does not affect the excimer fluorescence of the film, indicating that the monomers' packing with their diazaanthracene units stacked face‐to‐face is retained—a prerequisite for successful polymerization. The monomer film can be polymerized in confined areas on solid substrates by UV irradiation with a confocal microscope laser. The underlying chemistry of the polymerization, a [4+4]‐cycloaddition of the diazaanthracene units, leads to disappearance of the fluorescence in the irradiated regions which enables writing into the monolayer on a µm scale—thus the term “molecular paper.” The reaction can be reversed by heating which leads to a recovery of the fluorescence and to erasing of the writing. Alternative pathways for this phenomenon are discussed and control experiments are conducted to rule them out.     

A study on the accuracy of force analogy method in nonlinear static analysis

In this paper, the accuracy of the force analogy method (FAM) for nonlinear static (pushover) analysis is investigated. Hence, after explanation of the concept of FAM by a new approach, 12 2D steel special moment resisting frames with different configurations were derived from two different 3D archetypes and modeled using four various methods of capturing nonlinearity including SAP2000 super elements, OpenSees force‐based and displacement‐based fiber method, and FAM. In addition, a MATLAB code was developed for modeling and analyzing the frames by FAM. The accuracy of FAM in predictions of pushover curves, base shear forces, and plastic rotation of the critical hinges was investigated. The results indicated that in general, the predictions obtained using the FAM had a good agreement and compatibility with those from other methods of analysis currently used in practice for seismic performance assessment of structures.