Elucidation of chemical structures of pink-red pigments responsible for ‘pinking’ in macerated onion (Allium cepa L.) using HPLC-DAD and tandem mass spectrometry

The chemical structures of pink-red pigments responsible for ‘pinking’ in macerated onion were tentatively elucidated using HPLC with a diode array detector and tandem mass spectrometry. All pigments were produced in conditions that approximated the natural process as closely as possible, using mixtures of onion thiosulphinates, the enzyme alliinase, and free amino acids. The isotopic distribution of protonated molecules of pink-red pigments produced from individual amino acids indicated the absence of sulphur, with the exception of pigment produced from cystine. The pigments had a basic polymethine framework containing two pyrrole rings (3,4-dimethyl-1H-pyrrole and 3,4-dimethyl-2,5-dihydro-1H-pyrrole) bridged by methines. The side chains attached to the nitrogen of the pyrrole rings were derived from the reacting amino acid. The simplest pink-red pigment, produced from glycine, was identified as 2-(2-(3-(1-(carboxymethyl)-3,4-dimethyl-1H-pyrrol-2(5H)-ylidene)prop-1-en-1-yl)-3,4-dimethyl-1H-pyrrol-1-yl)acetic acid. The pigment from alanine was identified as 2-(2-(3-(1-(carboxymethyl)-3,4-dimethyl-1H-pyrrol-2-yl)allylidene)-3,4-dimethyl-2,5-dihydro-1H-pyrrol-1-yl)propanoic acid. The chemical structures of pink-red pigments from leucine, asparagine, glutamine, tyrosine, and cystine also were determined.     

Acetamide‐modified hyper‐cross‐linked resin: Synthesis,characterization, and adsorption performance to phenol from aqueous solution

Acetamide‐modified hyper‐cross‐linked resin, HCP‐HMTA‐AA, was prepared and its adsorption performance was evaluated using phenol as the adsorbate. The prepared HCP–HMTA–AA owned predominant micro/mesopores and medium polarity, making it possess a superior adsorption to phenol as compared with polystyrene (PS), chloromethylated polystyrene (CMPS), hyper‐cross‐linked polymer (HCP) and amino‐modified hyper‐cross‐linked resin (HCP–HMTA). The adsorption enthalpy was ?99.56 kJ/mol at zero fractional loading, multiple hydrogen bonding contributed to such a great adsorption enthalpy and an approximately planar hexahydric ring was formed between acetamide of HCP–HMTA–AA and phenol. The dynamic capacity of phenol on HCP–HMTA–AA was 291.3 mg/g at a feed concentration of 946.2 mg/L and a flow rate of 48 mL/h and the resin column was almost regenerated by a mixed solvent including 50% of ethanol (v/v) and 0.01 mol/L of sodium hydroxide (w/v). HCP–HMTA–AA was repeatedly used for five times and the equilibrium adsorption capacity for the five time reached 94.2% of the equilibrium adsorption capacity for the first time. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41597.     

Recent Progress of Innovative Perovskite Hybrid Solar Cells

Recently, innovative perovskite hybrid solar cells have attracted great interest in solar cell research fields, such as dye-sensitized solar cells, organic photovoltaics, thin-film solar cells, and silicon solar cells, because their device efficiencies are gradually approaching those of crystalline Si solar cells, and they can be fabricated by cheap low-temperature solution processes. Here, we review the recent progress of innovative perovskite hybrid solar cells. The introduction includes the general concerns about solar cells and why we need innovative solar cells. The second part explains the structure and the material properties of hybrid perovskite materials. We focus on why the hybrid perovskite materials can exhibit excellent solar cell properties, such as high open-circuit voltage. The third part introduces recent progress in innovative perovskite hybrid solar cells, in terms of device architecture and deposition methods for dense perovskite thin films with full surface coverage. The device architecture is important in attaining high power conversion efficiency; the device operating mechanism is dependent on the device structure; and the pinhole-free dense perovskite thin films with full surface coverage are crucial for achieving high efficiency. Finally, we summarize the recent progress in perovskite hybrid solar cells, and the issues to be solved, in the summary and outlook section.     

Modeling of friction-stir butt-welds and its application in automotive bumper impact performance Part 1. Thermo-mechanical weld process modeling

The demand for better structural performance in joining of components for road vehicles prompts the implementation of aluminum alloy friction stir welding technology in the automotive industry. The aim of current study is the creation of a 3-D finite element (FE) friction thermal model and stir welding (FSW) process of dissimilar aluminum alloy and for the estimation of crash worthiness performance of FSW fabricated shock absorber assembly. Thermo mechanical simulations and analysis are performed to understand the thermal behavior in the FSW weld zones. The developed models are correlated against published experimental results in terms of temperature profile of the weld zone. The developed models are then implemented for fabricating vehicle bumper parts to illustrate the performance of FSW welded components during an impact. Customary sled testing for low-speed guard necessities is performed utilizing a grating blend welded test apparatus at Wichita State University (WSU) at the National Institute for Aviation Research (NIAR). A few guard congregations are then appended to the test installation utilizing FSW and conventional Gas bend GMAW welding strategies. Numerical models are likewise created where limited component investigation is utilized to contrast the anticipated harm and the real harm maintained by both of the FSW and GMAW manufactured guards. During the research, a new FSW weld mold is created that allows for a better representation of the desired progressive crack propagation. The FSW fabricated bumper based on the Johnson-Cook failure model yields better failure prediction and is in good agreement to the test. The results from this study provide a guideline for an accurate finite element modeling of a FSW fabricated components and their application in the crashworthiness of such structural components.     

Camphor sulfonic acid doped polyaniline-tin oxide hybrid nanocomposites: Synthesis,structural, morphological,optical and electrical transport properties

Camphor sulfonic acid (CSA) doped PANi–SnO₂ hybrid nanocomposites were synthesized by solid-state synthesis route with varying amounts (10–50%) of CSA. X-ray diffraction studies have proven the successful incorporation of CSA into the polyaniline–SnO₂ hybrid nanocomposites and the results are also supported by microstructural analysis. UV–visible and Fourier infrared spectroscopy studies have provided insight into the electronic interaction between the CSA, polyaniline, and SnO₂. The room temperature dc electrical conductivity of CSA-doped PANi–SnO₂ hybrid nanocomposite films were observed to depend on the amount of CSA doping and the morphology.     

Concrete filled high strength steel box columns for tall buildings: Behaviour and design

This paper presents a study of the behaviour and design of concrete filled high strength steel fabricated box columns for use in tall buildings. The many advantages that can be attributed to the use of high strength steel in concrete filled steel box column constructions are presented and discussed. The paper deals with short composite columns and presents guidelines for plate slenderness and overall column slenderness to eliminate local and overall buckling. A proposed design model is developed to calculate the strength of short columns in bending and compression. A method for constructing the strength interaction diagram is presented. Furthermore, to study the ductility of this form of column construction a cross-sectional analysis computer program was developed to consider the moment-thrust-curvature response of such members. This has been undertaken using mild structural steel and high strength steel. The study also shows that, by the use of the method considered, savings can be made in the base column design of a tall building with a negligible penalty in ductility. Finally, recommendations are given for further research into this new method of column construction, which focuses on future experimental work.