Livingstonbredahl4672

Rolling resistance is one of the most important properties of a tire which is highly dependent on the viscoelastic properties of its rubber compounds. There are a lot of ways to reduce this parameter both in construction improvement of the tire and changing in rubber compound formulation especially in tire tread formulation. Rubber scientists have been trying to introduce new processing aid agents beyond the traditional tire components for reducing the rolling resistance. In this study, a unique structure of silica-supported calix[4]arene (SS-CSC[4]A) has been synthesized and applied as a processing aid agent in tire tread formulation. Fourier-transform infrared spectroscopy (FTIR), Nuclear Magnetic Resonance (1HNMR and 13CNMR), 29Si CP/MAS spectroscopy, thermal gravimetric analysis (TGA), elemental analysis, and acid-base titration were used to characterize its structure. Scanning Electron Microscopy (SEM) use to investigate the effect of prepared material on qualification of filler dispersion in the rubber matrix. The viscoelastic properties of the prepared rubber compound were measured by Dynamic Mechanical Thermal Analysis (DMTA) which showed the great decrease in rolling resistance of rubber compound based on SS-CSC[4]A as a processing aid agent. The mechanical and rheological properties of obtained tread rubber compound measured by tensometer and MDR rheometer showed no sensible changes in these properties.Copper, like iron and zinc, is one of the most essential trace elements for organisms. Different forms of copper have distinctive and specific uses. For example, copper oxide nanoparticles (CuO-NP) are widely used in the world as a nanomaterial. Copper sulphate (CuSO4) is worldwide used as a fungicide in agriculture and as an algaecide in aquaculture. Nowadays, the increasing use of these chemicals raises concerns regarding their potential effects on the health of aquatic organisms and ecological risks. Therefore, in the present research, toxic effects of CuSO4 and CuO-NP, alone and in combination, were evaluated using biochemical markers (plasma biochemical and gill and liver oxidative stress) in freshwater fish, Oreochromis niloticus. The fish were exposed to 0.05 mg/L CuSO4, CuO-NP, and CuSO4+CuO-NP for 4 and 21 days. Especially at 21 days, CuSO4 and CuO-NP, alone and combined, generally increased plasma alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, cortisol, glucose, creatinine, blood urea nitrogen, and tissue malondialdehyde while they decreased plasma total protein, and tissue superoxide dismutase, catalase, glutathione-S-transferase, glutathione reductase, and glutathione. Consequently, our results illustrate that CuSO4 and CuO-NP have similar toxic effects in fish, however, co-exposure of CuO-NP and CuSO4 is more toxic than effects of these chemicals alone.This work describes the investigation of separation performance of the p-tert-butyl(tetradecyloxy)calix[6]arene (C6A-C10-OH) as stationary phase for gas chromatography (GC) separations. Its structure was characterized by IR, 1H NMR, 13C NMR, MS and single-crystal X-ray diffraction analysis. The C6A-C10-OH column shows good separation capacity for aliphatic, aromatic and cis-/trans- isomers. Selleck Danirixin Especially, it exhibits multiple molecular recognition interactions for the analytes with a wide range of polarity, including dispersion, π-π, H-bonding and dipole-dipole interactions. The present work provides experimental and theoretical basis for the designing of the new calixarene stationary phases in GC analyses.The purpose of this study was to explore the effects of the heuristics on the reasoning processes of pre-service science teachers on the topic of melting and boiling point using the ten heuristic model proposed by Talanquer. In this phenomenographic study carried out in the spring semester of the 2018-2019 academic year, interviews were conducted with 30 teacher candidates enrolled in the Science Teaching Program of Firat University Faculty of Education. Participants were asked to answer three different questions during the interviews. These questions were about the ranking of some compounds according to their melting or boiling points. Six different answer patterns for each question were obtained from the answers. The findings of this study showed that students generally used shortcut strategies instead of analytical/scientific reasoning, as all ten heuristics affected participants' reasoning. This study also revealed that although not included in the model proposed by Talanquer, periodic trends heuristic also influenced participants' reasoning about the melting and boiling point.The paper presents a study in which 54 university students were introduced to a newly developed, free, web-based 3DChemMol molecular editor with a toolbar, which they then evaluated. The tool aims to increase representational competence related to submicroscopic representations. Students who used the software for the first time, were instructed to create molecular models using the model building/editing tools in three activities with varying levels of difficulty 1) building a simple model (butanoic acid), 2) converting one model (hexane) into two models, 3) converting from a non-cyclic to a cyclic structure (glucose). It took students from two up to 15 minutes to accomplish each of the activities. Several types of help were available in the 3DChemMol molecular editor toolbar to assist students during their activities, including a video tutorial, button hovering, action status display, and a help menu. Undo/redo and restart options were also available. Students' completion level, difficulties, and use of the help features were investigated using student self-evaluation questionnaires. The 3DChemMol molecular editor proved to be a useful support for students in completing simple chemistry activities. Students were successful in model building, although they encountered some specific difficulties, especially in steps that involved spatial operations, such as rotating the selected part of molecule around the bond. In students' perception, the video tutorials were the preferred and most frequently used type of help, and the undo function was considered essential. The results suggest that the 3DChemMol molecular editor can be used effectively in introductory chemistry courses at the tertiary level, whether for direct instruction, self-study, or other forms of support in the pedagogical process. The results and new findings of this study will be used to further optimize the interface in future versions of the evaluated tool.Cerium carbonate crystal morphology is predicted using density functional theory (DFT) simulations in this paper. In the nucleation phase, the ketone group in polyvinylpyrrolidone (PVP) will preferentially bind to Ce3+ to form complexes and provide heterogeneous nucleation sites for the system, prompting the nucleation of cerium carbonate crystals. In the growth stage, due to the adsorption of PVP, the probability of (120) crystal plane appearing in the equilibrium state is the greatest, resulting in the formation of hexagonal flake cerium carbonate crystals with (120) crystal plane as the oblique edge. Experimentally, hexagonal sheet cerium carbonate crystals were successfully prepared using PVP as a template agent. Therefore, DFT can be used to predict the morphology of cerium carbonate crystals, which not only elucidates the growth mechanism of cerium carbonate crystals, but also greatly reduces the experimental cost.Mononuclear NiL complex was prepared by the use of bis-N,N'-salicylidene-1,3-propanediamine and Ni(II) salts. NiL was treated with ZnBr2 and pyrazole and 3,5-lutidine coligands in a dioxane medium to prepare the following diheteronuclear complexes [NiL·ZnBr2·(pyrazole)2] and [NiL·ZnBr2·(3,5-lutidine)2]. The complexes were characterized by elemental analysis, TG, IR and mass spectrometry. The effects of heterocyclic one- and two- nitrogen atoms containing co-ligands were also examined. Theoretical formation enthalpies, dipole moments and the relative levels of HOMO and LUMO energies were determined by the use of Gaussian09 program. The occupancy levels of the atomic orbitals were determined by the NBO analysis of Gaussian09. The effect of pyrazole and lutidine upon the complex formation was evaluated by the use of X-ray diffraction, TG and theoretical calculations. NiL complex with lutidine forms a square pyramidal conformation since lutidine is a much stronger coligand than pyrazole.Three new zinc(II) and one vanadium(V) complexes, [Zn2Cl2L2] (1), [Zn2I2L2] (2), [ZnCl2(HL)] (3), and [V2O2(μ-O)2L2] (4), where L is 5-bromo-2-((2-(methylamino)ethylimino)methyl)phenolate, have been synthesized and characterized by elemental analyses, IR and UV-Vis spectra, as well as molar conductivity. Structures of the complexes were confirmed by single crystal X-ray diffraction. Complexes 1 and 2 are isostructural dinuclear zinc compounds, with the Zn atoms in square pyramidal coordination. The Zn atoms in the mononuclear complex 3 are in tetrahedral coordination. Complex 4 is a dinuclear vanadium(V) compound, with the V atoms in octahedral coordination. The complexes were assayed for antibacterial activities by MTT method.The scientific interest in developing the advanced metal based compounds to inhibit and control bacterial infections is continuously rising. Keeping in view their pharmacological significance, two new bioactive symmetrical phenylenediamine mono- and bis-Schiff bases, 2-[(4-aminophenyl)imino]methyl-6-methoxyphenol (L1) and 2,2'-benzene-1,2-diylbis[nitrilomethylylidene]bis(6-methoxyphenol) (L2) have been synthesized and characterized by using physical techniques, spectral methods, elemental and DFT based computational analysis with B3LYP/6-311++G(d, p) basis set. Furthermore, the synthesized ligands were complexed with VO, Mn, Co, Ni, Cu and Zn ions in ratio [ML,12 and 11], respectively. All the complexes exhibited significant antibacterial action against all tested bacterial strains. But overall, the zinc complexes possessed higher antibacterial activity. These results concluded that metal complexes might be promising induction in the upcoming time for medical purposes.Two new oxidovanadium(V) complexes, [VOL1(aha)]DMF (1) and [VOL2(mat)] (2), where L1 and L2 are the dianionic form of N'-(4-bromo-2-hydroxybenzylidene)-3-methyl-4-nitrobenzohydrazide and N'-(3,5-dibromo-2-hydroxybenzylidene)pivalohydrazide, respectively, and aha and mat are the monoanionic form of acetohydroxamic acid and maltol, respectively, have been synthesized and structurally characterized by physico-chemical methods and single crystal X-ray determination. X-ray analysis indicates that the V atoms in the complexes are in octahedral coordination. Crystal structures of the complexes are stabilized by hydrogen bonds. The catalytic property for epoxidation of styrene by the complexes was evaluated.In this study, it is aimed to develop glucose/fructose sensitive poly(ethylene glycol) methyl ether methacrylate (PEGMA) particles which can be employed in controlled drug delivery applications. For this purpose, a boric acid based crosslinker was synthesized using 4-vinylphenylboronic acid and its formation was confirmed by 1H-NMR and FT-IR analyses. Sugar-sensitive polymeric particles were then achieved using this crosslinker and PEGMA monomer in single step and surfactant free emulsion polymerization technique. Polymeric particles were characterized by DLS, SEM, and TEM in terms of size and morphology. In order to determine the sensitivity of the particles to sugar molecules, first Rhodamine B dye (as a model drug) loading experiments were performed. Then, the particles were subjected to glucose/fructose rich media and dye release was monitored as a function of time using UV-Vis spectrophotometry. The results of the current study revealed that the PEGMA particles were more sensitive to fructose (~39% release) compared to glucose (~25% release) at pH 7.