Removal of reactive red-120 and 4-(2-pyridylazo) resorcinol from aqueous samples by Fe3O4 magnetic nanoparticles using ionic liquid as modifier

The nanoparticles of Fe₃O₄ as well as the binary nanoparticles of ionic liquid and Fe₃O₄ (IL-Fe₃O₄) were synthesized for removal of reactive red 120 (RR-120) and 4-(2-pyridylazo) resorcinol (PAR) as model azo dyes from aqueous solutions. The mean size and the surface morphology of the nanoparticles were characterized by TEM, DLS, XRD, FTIR and TGA techniques. Adsorption of RR-120 and PAR was studied in a batch reactor at different experimental conditions such as nanoparticle dosage, dye concentration, pH of the solution, ionic strength, and contact time. Experimental results indicated that the IL-Fe₃O₄ nanoparticles had removed more than 98% of both dyes under the optimum operational conditions of a dosage of 60 mg, a pH of 2.5, and a contact time of 2 min when initial dyes concentrations of 10-200 mg L⁻¹ were used. The maximum adsorption capacity of IL-Fe₃O₄ was 166.67 and 49.26 mg g⁻¹ for RR-120 and PAR, respectively. The isotherm experiments revealed that the Langmuir model attained better fits to the equilibrium data than the Freundlich model. The Langmuir adsorption constants were 5.99 and 3.62 L mg⁻¹ for adsorptions of RR-120 and PAR, respectively. Both adsorption processes were endothermic and dyes could be desorbed from IL-Fe₃O₄ by using a mixed NaCl-acetone solution and adsorbent was reusable.     

An exact schedulability test for fixed-priority preemptive mixed-criticality real-time systems

The current literature of fixed-priority scheduling algorithms relies on sufficient tests to determine if a set of mixed-criticality sporadic tasks is schedulable on a single processor. The drawback of these safe tests is their pessimism, a matter that could be solved if an exact schedulability analysis is used. However, because of the non-deterministic behavior of tasks in the mentioned setups, exact quantification of worst-case response times, needed for the test, is a difficult problem; more precisely, such a quantification needs evaluation of enormous sequences of job executions. The core problem is thus to merge such sequences to make the analysis practical. This paper, for the first time, gives an algorithm for exact worst-case response time characterization of mixed-criticality sporadic real-time tasks executing according to a given fixed-priority scheduler. We use a set of techniques which carefully consider the task properties and their relation to the worst scenarios to prune the analysis state space. We also show an interesting result that if an exact schedulability test is used, the Audsley’s optimal priority assignment algorithm is not applicable to the mixed-criticality case. Accordingly, we need new priority assignment algorithms to work with the exact test; we give a simple task priority assignment algorithm to this aim. The performance of the proposed exact test (in terms of time complexity) is examined and the effectiveness of some heuristic priority assignment algorithms using the test (in terms of the ratio of task sets which are deemed schedulable) are compared.     

Influence of CaTiO3 impurity in SHS-TiN powder on the mechanical properties of ZrO2–TiN composites

Yttria-stabilised tetragonal polycrystalline ZrO₂-based composites with 40 vol.% TiN were hot pressed at 1450 °C for 1 h using a jet-milled thermally synthesized and a self-propagating high-temperature synthesis (SHS) TiN powder. The ZrO₂ phase of the SHS-TiN powder-based composites was found to be substantially coarser than for the jet-milled TiN powder-based ceramics and prone to spontaneous transformation to m-ZrO₂ and microcracking, due to the CaTiO₃ impurity in the SHS-TiN starting powder. In order to prove this, a set of experiments was performed to investigate the effect of the addition of CaO and TiO₂ on an yttria-stabilised tetragonal ZrO₂ polycrystalline (Y-TZP). The addition of 0.2 mol% of CaO to a Y-TZP ceramic was found to destabilise the t-ZrO₂ phase, whereas the addition of 1 mol% TiO₂ results in significant grain growth and the formation of less transformable t-ZrO₂. The CaTiO₃ impurity could be removed from the SHS-TiN powder by hot hydrochloric acid leaching, allowing to obtain a similar microstructure and mechanical properties as with conventional TiN powder.     

High flux nanofibrous membranes for colored effluent treatment

In this study, polyamide 66 (PA) and polyacrylonitrile (PAN) were electrospun with various arrangements on substrate surface. Spunbond–Meltblown–Spunbond polypropylene nonwoven (SMS) and carbon foam were applied as substrate to evaluate how filtration efficiency and flux is affected. In addition to substrate, the influence of polymer concentration and layer arrangement were studied. Taghuchi design was utilized for optimum structure recognition. A vat dye was used to study the filtration efficiency. The results have revealed that substrate type plays as the most effective factor among all parameters. SMS substrate was led to finer fibers fabrication, smaller pores, and therefore, superior filtration efficiency and higher flux. Although layer arrangement showed less impression than substrate, it was more effective than polymer concentration. Furthermore study on the base of Taghuchi design showed that by applying PAN/PA/PAN composite nanofibrous membrane on SMS substrate, a high filtration efficiency can be achieved by reduction of 99.58 and 86.13% turbidity and chemical oxygen demand, respectively.     

Characterization of the produced electrospun fish gelatin nanofiber containing fucoxanthin

Food Science and Biotechnology - This study aims to prepare fish gelatin nanofibers extracted from fish waste by using electrospinning method and its encapsulation with fucoxanthin extracted from...     

Effect of silane-modified ZnO on morphology and properties of bionanocomposites based on poly(ester-amide) containing tyrosine linkages

In this study, various optically active poly(ester-amide)/Zinc oxide bionanocomposites (PEA/ZnO BNCs) were synthesized with different amount of modified ZnO nanoparticles using ultrasonic irradiation. To obtain the homogeneous distribution of ZnO in polymer matrix, the surface of nanoparticles was modified to organophile with ??-aminopropyltriethoxyl silane. PEA/ZnO BNCs were characterized by Fourier transform infrared spectra, X-ray diffraction, field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The FE-SEM, AFM, and TEM results confirmed that the nanoparticles were dispersed uniformly in PEA matrix at the nanoscale. In addition, thermogravimetric analysis data indicated an improvement of thermal stability of novel BNC materials as compared to the pure polymer.     

Effect of structural parameters of porous yarns and fabric on air permeability and moisture transfer of double-face woven fabrics

In this study, effect of fabric structural parameters of double-face woven fabrics including kind of porous yarn namely micro-porous yarn and hollow yarn, hole size of hollow yarn, percentage of these yarns in double-face woven fabric structure, and finally weft density on air permeability and moisture transfer of woven fabrics was evaluated. These yarns were produced by using water-soluble continuous polyvinyl alcohol filaments as core part for hollow yarns and as doubling yarn in micro-porous yarn. Results revealed the effect of kind of porous yarn, hole size of hollow yarn, and weft density on air permeability and moisture transfer of woven fabrics. The percentage of porous yarns as weft did not show obvious trend. Analysis of variance was used to study the effect of these variables on air permeability and moisture transfer of double-face woven fabrics statistically.     

Improvement of photocatalytic decomposition of methyl orange by modified MWCNTs,prediction of degradation rate using statistical models

Multi-walled carbon nanotubes (MWCNTs) have been successfully modified with TiO₂ nanoparticles via a two-step hydrolysis technique. Firstly, the pristine MWCNTs are functionalized in nitric acid (HNO₃) to creation of oxygen containing groups. Secondly, TiO₂ nanoparticles are synthesized on the surface of functionalized MWCNTs through hydrolysis method. The synthesized samples have been used as photocatalyst for decomposition of methyl orange (MO) as dye organic pollutant. The characterization of samples using X-ray diffraction pattern (XRD) confirm the presence of TiO₂ nanoparticles with mixture of anatase and rutile phases. Regarding the photocatalytic performance of TiO₂ nanoparticles and modified MWCNTs with TiO₂ nanoparticles, it observed that the degradation rate of MO increases by increasing the irradiation time from 5 to 35 min. The variation of degradation rate upon pH of suspension reveals that the maximum and minimum degradation rate are in acidic (pH?=?3) and neutral condition (pH?=?7). Meanwhile, the results show that the presence of MWCNTs leads to the enhancement of degradation rate. The analysis of variance (ANOVA) results confirm that both of main factors (irradiation time and pH) and their interaction have a significant influence on the degradation rate of MO. However, the effect of irradiation time is more than that of pH and their interaction. The graphical methods verify the quality and adequacy of the statistical models for prediction of the degradation rate.