Microstructure and fracture mode of unalloyed dual phase austempered ductile iron

Dual phase ADI material microstructure consists of different amounts and morphologies of ausferrite and free ferrite, obtained by subjecting ductile iron to specific heat treatment. As such, its strength is lower compared to comparable ADI materials, but exhibiting a higher ductility, the major disadvantage of ADI. In the current study, an unalloyed ductile iron was intercritical austenitised in two-phase regions (?+?) at four temperatures from 840 to 780?C for 2 hours and austempered at 400?C for 1 hour to obtain dual phase ADI with different percentages of free ferrite and ausferrite. Metallographic and fracture studies were performed by light and scanning electron microscopy, respectively. Microscopy results were correlated to tensile testing results. The results indicated that, as the amount of ausferrite present in the matrix increases, higher values of strength and lower ductility are obtained. The fracture surfaces of dual phase ADI microstructures with 22.8% of ausferrite in their matrix have regions of quasi-cleavage fracture around last-to-freeze zones, related to the presence of ausferrite in those areas. The specimens with the highest values of ausferrite of 86.8% among the dual phase microstructure have a dominant quasi-cleavage type of fracture.

The impact of enological products for tartaric stabilization on wine filterability

The aim of this research was to evaluate the impact of most commonly used agents for tartaric stabilization of wine, such as metatartaric acid, carboxymethyl cellulose (CMC), mannoproteins and gum arabic, on the filterability of white, rose and red wine previously pre-filtered and prepared for the final filtration and bottling. Wine filterability after sweetening with rectified concentrated must was also assessed. The experiments were carried out using Quality Filterability Test and the obtained results were expressed through filterability index (FI), and maximum filterable volume (Vmax). The results confirmed that used enological agents for the inhibition of tartaric instabilities generally did not worsen the filterability of white and rose wine (FI<20). However, it was evident that products containing mannoproteins and metatartaric acid considerably reduced red wine filterability (FI>500). The correlation between white and rose wine turbidity and filterability was recorded in the trials but the same trend was not registered for the red wine. The results of this study are important since membrane (final) filtration of improperly prepared wine characterized by low filterability can both increase the costs and lead to hold up on the bottling line.

Numerical study of the hydrodynamics and mass transfer in the external loop airlift reactor

The objective of this study was to investigate the hydrodynamics and the gas-liquid mass transfer coefficient of an external-loop airlift reactor (ELAR). The ELAR was operated in three cases: different inlet velocities of fluids, different alcohols solutions (water, 0.5% methanol, 0.5% ethanol, 0.5% propanol and 0.5% butanol) and different concentration of methanol in solutions (0%, 0.5%, 1%, 2% and 5%). The influence of superficial gas velocity and various diluted alcohol solutions on hydrodynamics and gas-liquid mass transfer coefficient of the ELAR was studied. Experimentally, the gas hold-up, liquid velocities and volumetric mass transfer coefficient values in the riser and the downcomer were obtained from the literature source. A computational fluid dynamics (CFD) model was developed, based on two-phase flow, investigating different liquids regarding surface tension, assuming the ideal gas flow, applying the finite volume method and Eulerian-Eulerian model. The volumetric mass transfer coefficient was determined using CFD model, as well as artificial neural network model. The effects of liquid parameters and gas velocity on the characteristics of the gas-liquid mass transfer were simulated. These models were compared with appropriate experimental results. CFD model successfully succeed to simulate the influence of different alcohols regarding the number of C-atoms on hydrodynamics and mass transfer.

Thermal vision of fracture behavior on acrylic composites

The aim of this work was to investigate thermal properties of acrylate-based composite combined with alumina-based particles. The composites were made of poly (methyl methacrylate) (PMMA) modified with dimethyl itaconate (DMI) as a matrix. As reinforcement were used alumina particles (Al2O3) and alumina doped with iron oxide (Al2O3-Fe) modified with 3-aminopropyl-trimethoxylane (AM) and flax oil fatty acid methyl esters (biodiesel - BD). According to the thermal conductivity measurements, the highest thermal conductivity values had the composite with alumina particles with the highest alpha phase content. With the addition of modified alumina particles to PMMA/DMI matrix mechanical properties were improved (tensile strength, modulus of elasticity and elongation at break). Composite with 3 wt. % Al2O3-Fe-AM particles had the most improved mechanical properties. It was noticed that this composite, compared to PMMA, had the lowest temperature in a crack zone (10.28%) and that is due to the better stiffness and highest thermal conductivity. The results indicated that the Sobel fractured surface area is related to the crack energy, which is reflected by the temperature of sample monitored by thermal vision.

Liquefied fuel from plastic wastes using nitro cracking method with refinery distillation bubble cap plate column

Development and modernization have resulted in an immense increase in the production of all kinds of goods, which indirectly produce waste to the globe. Plastic was one of the materials that produce more waste due to its wide range of applications due to its versatility and relatively low cost. In most cases, thermoplastics polymer makes up a high proportion of waste and steadily increasing worldwide pollution to the environment. As a result, waste plastics pose a severe environmental challenge due to their non-biodegradable properties and disposal problems. Diverse innovations are being developed to address plastic drawbacks, which can boost the profits of the recycling industry and shrink the world plastic waste landfills. As a part of recycling, the present work is aimed to produce liquefied fuel through the nitro cracking method using pyrolysis reactor induced with bubble cap plate column with Y zeolite as a catalyst. The liquefied fuel results produced from plastic wastes (plastics bags, plastic bottles, packing materials, and medical plastics) are compared with fuel produced from virgin plastics. The 8% higher pyrolytic oil yield is achieved compared with the results of oil produced without catalyst, and 82% of total waste plastic material is converted into liquefied fuel by the presence of a catalyst. FTIR, GC-MS, Bomb Calorimeter characterize the obtained fuel results by adopting the standard ASTM methods, and the results were compared with virgin and waste plastics.

Pine cones powder for the adsorptive removal of copper ions from water

This research investigates the adsorption potential of pine cones powder (PCP) for the removal of copper ions (Cu(II)) from aqueous solutions. The process of adsorption was reasonably fast to be completed within a time of 60 min. The pseudo-second order kinetic model describes properly the Cu(II) adsorption by PCP. The adsorbent was characterised by various instrumental techniques and batch experiments were conducted to investigate the effect of PCP dose, solution pH, particle size and initial Cu(II) concentration on adsorption efficiency. Optimum Cu(II) removal occurred at a slightly acidic pH, with a particle size less than 100 ?m. The effective PCP dose was estimated to be 36 g.L-1. The increase in the initial concentration of Cu (II) was accompanied by a reduction in the rate of its reduction by almost half. The Langmuir model was the best fitting isotherm with a maximum adsorption capacity of 9.08 mg.g-1. The thermodynamic parameters values showed that the Cu(II) adsorption was a spontaneous and endothermic process. The results of this research suggest that Cu(II) could be removed through an environmentally friendly process using PCP as low-cost natural wastes.

Heat transfer studies of Al2O3/water-ethylene glycol nanofluid using factorial design analysis

The experimental study of heat transfer coefficient of nanofluid plays a significant role in improving the heat transfer rate of the heat exchanger. The research was conducted in a natural convection heat transfer apparatus by suspending Al2O3 nanoparticle in a base fluid of Water-Ethylene glycol mixture. The effects of heat input (A), nanoparticle volume fraction (B), and base fluid concentration (C) on experimental heat transfer coefficient (hexpnf) were studied. By the results obtained by MINITDesign software 23 full factorial design matrix, 16 experimental runs were performed with the lower and higher level of input factors. The levels for heat input are 10 and 100 W; nanoparticle volume fraction is 0.1 and 1 volume% and for base fluid concentration is 30 and 50 volume% of Ethylene Glycol in water. From the obtained experimental results residual plots, Pareto chart, contour plot and 3D surface plots were drawn. It can be found from the study that the experimental heat transfer coefficient showed highest enhancement with high level of nanoparticle volume fraction and moderate enhancement with high level of heat input and slight enhancement with base fluid concentration.

Application of the model of cylindrical reactor for self-purification by indigenous microorganisms

Pharmaceutically Active Compounds (PhACs), in particular, Nonsteroidal anti-inflammatory drugs (NSAIDs) are in increasingly wider usage, and as such are more and more frequently part of the organic matter of recipient rivers, especially in their lower course. To indicate their significance as pollutants, as well as the significant role that the presence of autochthonous microflora plays in solving this issue, we undertook to perform this experiment. The experiment, titled ?Application of the Model of Cylindrical Reactor In Self-purification by Indigenous Microorganisms?, was conducted during one year period at the location of Vukovci, in the lower course of Moraca river. Assuming that the concentration of NSAIDs and PhACs in water can be reduced through self-purification, it has been proven that such processes result in a modification of phenotype in the indigenous microbiological population. Having the abovementioned premise in mind, we constructed the experiment model, which entails kineticism of water, whereas the defined volume flow rate per unit time was 0.005 m/s; through the known distance of 432 m. Over one year of application of the model of the cylindrical reactor for enhancing self-purification capacity by indigenous microorganisms, auto-purification increased by 28.05%, the phenotype of the indigenous microorganisms changed by 24.62%, whereas the total concentration of particular PhACs, micropollutants, and NSAIDs decreased by 4.19%.

Influence of graphene nano-platelets dispersion on the thermo-physical properties of sunflower oil

In this article, thermal stability, viscosity, density and surface tension of Graphene nano-platelets dispersed sunflower oil are experimentally determined by varying the Graphene concentration (0.1-1.1wt%) and temperature (40-100?C). The SEM micrograph and the EDS spectra are used to characterize the Graphene. Nanofluids are prepared by ultrasonication technique (two-step method) and the maximum thermal stability of about 280?C is achieved at 1.1wt% Graphene nanofluids. The dynamic viscosity diminished in an exponential shape in acquiescence with Arrhenius equation and the densities of samples are characteristic with linear decrement in the estimated temperature range. Density and surface tension increases with the Graphene concentration, while a reverse trend is observed with temperature rise. The maximum thermal stability, viscosity, density and surface tension is obtained in the nanofluid with 1.1 wt% concentration and the minimum is obtained in the nanofluid with 0.1 wt% concentration.

Enhanced photocatalytic oxidation of reactive dye using manganese catalyst complex

In this work, the treatment efficiency of advanced oxidation processes H2O2/UV enhanced by the addition of a manganese catalyst complex (MnTACN) was investigated on a model dye solution and a real dye-house effluent. The experimental results were evaluated in terms of absorbance (A) and total organic carbon (TOC) reduction. The major degradation products of the model dye solution were identified by high resolution gas chromatography/mass spectrometry analyses. In addition, the toxicity of the final reaction solution after H2O2/UV/MnTACN treatment to Vibrio fischeri bacteria was determined. The results showed that the addition of the H2O2/UV/MnTACN system at in different concentrations of the catalyst solution increased enhance the decolourization rate compared to H2O2/UV for both the model dye solution and real dye-house effluent.