Retracted papers by Iranian authors: causes,journals, time lags,affiliations, collaborations

Scientometrics - This study aims to analyze 343 retraction notices indexed in the Scopus database, published in 2001–2019, related to scientific articles (co-)written by at least one author...     

A Cluster-based Stratified Hybrid Decision Support Model under Uncertainty: Sustainable Healthcare Landfill Location Selection

Applied Intelligence - Nowadays, healthcare waste management has become one of the significant environmental, health, and social problems. Due to population and urbanization growth and an increase...     

Investigation of structure and mechanical properties of toughened poly(l‐lactide)/thermoplastic poly(ester urethane) blends

In this study, poly(l ‐lactide) (PLA) is melt‐blended with thermoplastic polyurethane (TPU) to modify the brittleness of PLA. An aliphatic ester‐based TPU was selected in order to have an ester sensitivity for degradation and an inherent biocompatibility. Using this compatible TPU, there was no need to apply problematic compatibilizers, so the main positive properties of PLA such as biocompatibility and degradability were not challenged. The detected microstructure of PLA/TPU blends showed that when the TPU content was lower than 25 wt %, the structure appeared as sea‐islands, but when the TPU content was increased, the morphology was converted to a cocontinuous microstructure. A higher interfacial surface area in the blend with 25 wt % TPU (PLA25) resulted in a higher toughness and abrasion resistance. The various analyses confirmed interactions and successful coupling of two phases and confirmed that melt‐blending of PLA with the aliphatic ester‐based TPU is a convenient, cost‐effective, and efficient method to conquer the brittleness of PLA. The prepared blends are general‐purpose plastics, but PLA25 showed an optimum mechanical strength, toughness, and biocompatibility suitable for a wide range of applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43104.     

Wrapping carbon nanotubes by biopolymer chains: Role of nanointerfaces in detection of vapors in conductive polymer composite transducers

Chitosan (CS) and hydrophobic‐modified chitosan (HM‐CS) chains were wrapped onto multiwalled carbon nanotubes (MWNTs) and introduced to polyvinyl alcohol (PVA) matrices as nanohybrid conductive polymer composites (CPCs) for detection of polar vapors. The effect of grafted alkyl groups on polarity of CS chains were studied by quantum mechanics (QM). The designed composites were applied as sensitive layers to clarify the response mechanism in CPCs gas sensors. It was realized that the wrapped biopolymers intensely influenced the sensitivity of the composites. Experiment results specified that the nature of biomacromolecules and their interactions with vapor molecules affects the resistance change in CPCs. The higher interaction of CS with polar vapor molecules caused more plasticization of polymer segments in the MWNTs connections. Such phenomenon enhanced the resistance change in the presence of analytes. Moreover, it was inferred that the semiconductor character of MWNTs has an important effect in the final signals. The more polar structure of CS in comparison with HM‐CS enhanced the adsorption of vapor molecules on the surface of MWNTs, and the electron donor analytes decreased the conductivity of p‐type MWNTs increasing the final responses. The presented results corroborate that the performance of CPCs gas sensors could be finely tuned through manipulation of the nanointerfaces. POLYM. COMPOS., 37:2803–2810, 2016. © 2015 Society of Plastics Engineers     

CFD study of non-premixed swirling burners: Effect of turbulence models

This research investigates a numerical simulation of swirling turbulent non-premixed combustion. The effects on the combustion characteristics are examined with three turbulence models: namely as the Reynolds stress model, spectral turbulence analysis and Re-Normalization Group. In addition, the P-1 and discrete ordinate (DO) models are used to simulate the radiative heat transfer in this model. The governing equations associated with the required boundary conditions are solved using the numerical model. The accuracy of this model is validated with the published experimental data and the comparison elucidates that there is a reasonable agreement between the obtained values from this model and the corresponding experimental quantities. Among different models proposed in this research, the Reynolds stress model with the Probability Density Function (PDF) approach is more accurate (nearly up to 50%) than other turbulent models for a swirling flow field. Regarding the effect of radiative heat transfer model, it is observed that the discrete ordinate model is more precise than the P-1 model in anticipating the experimental behavior. This model is able to simulate the subcritical nature of the isothermal flow as well as the size and shape of the internal recirculation induced by the swirl due to combustion.     

Modified guar gum: An alternative source for printing of cotton fabric with reactive dye

The alginate thickener is the thickener frequently used for reactive printing of textile. The thickener responds with reactive pigments and thus does not lead to the fabric composition becoming stiffer. In this study, we prepared oxidised natural guar gum with hydrogen peroxide, sodium hypochlorite and sodium hydroxide. All other polysaccharides comprise reactive hydroxyl units with a stronger reactivity that must be replaced if they are to be used in reactive printing. Guar derivatives were synthesised and verified using Fourier-transform infrared (FTIR) spectroscopy. Natural thickeners, synthetic guar gum derivatives, have been employed in textile printing technique. In comparison to other synthetic thickeners, modified environmental guar gum polymer has been shown to be an ecologically friendly and low-cost thickener. Cotton fabric printed with modified guar thickening with hydrogen peroxide has even stronger colour strength than fabric printed with sodium alginate thickener, which is highly favourable. Penetration properties, colour value, colour strength, colour fastness to washing, light and rubbing was compared with alginate thickener (readily available on the market). Guar gum thickeners showed enhanced features versus sodium alginate for reactive printing. Partially replaced guar gum is an appropriate option due to the colour and physical properties.     

纳米碳酸钙的制备及表征

研究了以氧化钙和二氧化碳为原料,化学法制备纳米碳酸钙的工艺条件、添加剂的影响及形态。结果表明:中间体氢氧化钙的初始浓度、二氧化碳的流量、反应温度、搅拌速度及添加剂等在控制制备纳米碳酸钙颗粒的形状和尺寸中均十分重要。透射电镜观察结果表明:通过控制反应及添加剂,可以得到尺寸规整的链锁形、纺锤形和球形纳米碳酸钙。表面能谱证实产品为高纯的碳酸钙。X射线衍射和电子衍射的结果进一步表明:所制纳米碳酸钙均属方解石型六方晶系,a0=0.498 9 nm,c0=1.706 2 nm;为多晶结构。     

GPC的浓度效应

本实验用东洋曹达 HLC-802A GPC 仪考察了几种窄分布聚苯乙烯样品和两种宽分布聚苯乙烯样品.结果表明:(1)在0.10～0.15g/100ml 浓度以下几乎没有浓度效应.(2)浓度再增加,淋洗体积随之增加。(3)分子量随浓度增加而降低,且峰加宽.(4)分子量大者,浓度效应显著.窄分布样品比宽分布样品明显.(5)流速大,浓度效应显著.