Inert Gas Flow Research Articles

Solid-State Investigation, Storage, and Separation of Pyrophoric PH3 and P2 H4 with α-Mg Formate.

Phosphane, PH3 -a highly pyrophoric and toxic gas-is frequently contaminated with H2 and P2 H4 , which makes its handling even more dangerous. The inexpensive metal-organic framework (MOF) magnesium formate, α-[Mg(O2 CH)2 ], can adsorb up to 10 wt % of PH3 . The PH3 -loaded MOF, PH3 @α-[Mg(O2 CH)2 ], is a non-pyrophoric, recoverable material that even allows brief handling in air, thereby minimizing the hazards associated with the handling and transport of phosphane. α-[Mg(O2 CH)2 ] further plays a critical role in purifying PH3 from H2 and P2 H4 : at 25 °C, H2 passes through the MOF channels without adsorption, whereas PH3 adsorbs readily and only slowly desorbs under a flow of inert gas (complete desorption time≈6 h). Diphosphane, P2 H4 , is strongly adsorbed and trapped within the MOF for at least 4 months. P2 H4 @α-[Mg(O2 CH)2 ] itself is not pyrophoric and is air- and light-stable at room temperature.

Effect of the Position in the Build Chamber on the Fatigue Strength of Additively Manufactured Maraging Steel MS1

The quality of additively produced parts and the achievable mechanical response may be affected by several factors, such as build orientation, heat treatment, or machining. A further rarely investigated factor is the position of the built part in the chamber with respect to inert gas flow. Previous studies have highlighted that the interaction between gas flow and laser track may induce an intense vaporization with consequent lack of fusion, particle entrainment, drop in density and denudation of the produced part, which is likely to detrimentally affect mechanical properties. This study addresses the effect of part position on the fatigue strength of heat-treated maraging steel MS1 produced by an EOSINT M280 machine in a nitrogen environment. Novelty arises from the lack of studies in this field, especially under fatigue. A factorial plan with subsequent statistical analysis highlighted that positioning the part upstream with respect to the gas flow leads to a slightly lower fatigue strength; however, no significant differences are observed. The failure mode, involving initiation from subsurface porosities of the same size, is also unaffected. Finally, a fatigue limit of 26% of the ultimate tensile strength is found, which is consistent with previous outcomes.

Optimal Co-pyrolysis of municipal sewage sludge and microalgae Chlorella Vulgaris: Products characterization, synergistic effects, mechanism, and reaction pathways

Co-pyrolysis of municipal sewage sludge (MSS) and microalgae Chlorella Vulgaris (MCV) was carried out in a fixed-bed reactor to investigate the effect of feedstocks interaction on pyrolysis products and synergistic effects. Based on previous authors' research, the optimum values of reaction parameters were T = 520 °C, mixing ratio (MCV/MSS) = 0.82, and an inert gas flow rate of 0.55 L/min. For the investigation of synergetic effects at optimum point, theoretical values anticipated from each characteristic were computed as an arithmetic sum of the single pyrolysis values obtained. For the first time, by using GC analysis, changes in gas components (H2, CO, CO2, CH4) at different temperatures (220–520 °C) and reaction times (0–30 min) have been investigated. Referring to GC-MS results the percentages of oxygen-containing species, alkanes, alkenes, aliphatic, aromatic, and total hydrocarbons were changed from the theoretical value of (41.719%), (6.004%), (11.215%), (17.219%), (4.317%), and (21.536%) to experimental value (39.292%), (3.693%), (12.103%), (15.796%), (0%), and (15.796%) respectively. Fatty acids and N&O-containing compounds (amides) were increased from (12.297%) to (26.009%) and (6.989%) to (16.217%), respectively. Co-pyrolysis bio-oil was rich in fatty acids and amides compounds. So, co-pyrolysis of sewage sludge and Chlorella Vulgaris provides a new orientation for high value-added utilization of biomass. It was observed that the nitrogen and oxygen content of biochar was reduced (0.29% and 1.01% respectively) compared to the theoretical condition. In the end, a comprehensive mechanism, synergistic, and reaction pathways of co-pyrolysis of MCV and MSS were presented.

Crotonic Acid Production by Pyrolysis and Vapor Fractionation of Mixed Microbial Culture-Based Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

Crotonic acid (CA) and trans-2-pentenoic acid (2-PA) can be obtained from renewable resources by pyrolysis of the bio-based poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) copolymer. In this study, direct pyrolysis of the PHBV-enriched biomass into CA and 2-PA was studied under an inert atmosphere and N2 carrier gas flow, aiming at obtaining high acid yields from mixed microbial cultures (MMCs). The highest yields of 80 ± 2% for CA and 67 ± 1% for 2-PA were obtained at conditions of 240 °C, 1 h, and 0.15 L/min nitrogen flow rate, corresponding to a mean hot vapor residence time of 20 s. A similar acid yield was achieved when the pyrolysis was performed under reduced pressure (150 mbar) instead of using nitrogen gas. The combined pyrolysis of extracted PHBV at 220 °C and 90 min with vapor fractionation by distillation resulted in yields of 81 and 92% for CA and 2-PA, respectively.

THERMAL STABILITY AND THERMODYNAMICS OF PYROLYSIS OF MONO-, BI-, AND TRINUCLEAR CARBINOL DERIVATIVES OF FERROCENE

Mono-, bi- and trinuclear carbinol derivatives of ferrocene C5H5FeC5H4-C(CH3)2OH (I), [C5H5FeC5H4]2C(CH3)OH (II), [C5H5FeC5H4]3C-OH (III) were synthesized. the thermal stability and thermodynamics of the pyrolysis of these compounds have been studied. The composition and structure of the synthesized compounds were established by elemental analysis (AAS, C, H analysis), 1H NMR, IR, and UV/visible spectroscopy. In the IR spectra of these compounds there are absorption bands with ν(OH) =2910-3040 cm-1 and ν(OH) = 3080-3190 cm-1 , and in the 1H NMR spectra there are absorption bands with chemical shift values δ(OH) = 4.29-4.18 ppm for OH groups that differ in position and are due to the formation of intra- and intermolecular associates with the participation of OH groups. The electronic absorption spectra indicate the presence of characteristic absorption bands in compounds I-III at λmax = 270 (I), 278 (II), and 285 nm (III). It is shown that when samples are heated from room temperature to 700 °C in an inert gas flow, the residual mass of compounds I-III is 2.05, 20.24, and 66.96% of the initial mass, respectively, and these compounds decompose to form nanosized iron particles. /iron oxide and carbon. The values of the melting temperature and saturation magnetization of nanosized iron particles formed during the pyrolysis of ferrocene and its derivatives I-III are calculated.

Active sites formation of molybdenum oxide catalyst for hydrocarbon conversion

The catalytic properties of molybdenum-alumina systems depend on the synthesis conditions. Herein, we considered the effect of MoO3/Al2O3 catalyst pretreatment conditions on their activity in propylene and propane conversion. MoO3/Al2O3 catalysts were synthesized by wetness impregnation of the support with a solution of molybdenum citrate complex and activated in different atmospheres at 550–590 °С. The maximum conversion of propylene and yields of metathesis products were observed for the sample activated in an inert gas flow. This is caused by the formation of precursors of the metathesis active sites in this sample, i.e. isolated surface monomolybdate species. Activation of the catalyst in hydrogen leads to the reduction of Mo6+ to Mo5+/Mo4+, which ensure the increased activity and selectivity in propane dehydrogenation. Therefore, it was shown that make it possible to purposefully change the properties of the same molybdenum-alumina catalyst to suit the problems of the specific reaction (metathesis, oligomerization, dehydrogenation, aromatization, cracking).

Safety assessment of the process Ester Industries, based on the recoSTAR PET FG technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panelon Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Ester Industries (EU register number RECYC261) using the recoSTAR PET FG technology. The input is hot washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post-consumer PET containers, mainly bottles, with no more than 5% PET from non-food consumer applications. The flakes are processed continuously under an inert gas flow. They are dried and crystallised in a first reactor and then further heated in a second reactor before being extruded into pellets. Having examined the challenge test provided, the Panelconcluded that the drying and crystallisation (step 2), and the heating of the crystallised flakes (step 3) are the critical steps that determine the decontamination efficiency of the process. The operating parameters to control the performance of these critical steps are temperature, residence time and gas flow rate. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1μg/kg food. Therefore, the Panelconcluded that the recycled PET obtained from this process is not of safety concern, when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs for long-term storage at room temperature, with or without hotfill. Trays made of this recycled PET are not intended to be used in microwave and conventional ovens and such use is not covered by this evaluation.

Effect of Deposition Parameters on Morphological and Compositional Characteristics of Electrodeposited CuFeO2 Film

Deposition parameters determine the characteristics of semiconductor films in electrodeposition. Thus, it is essential to understand the effect of deposition parameters on the electrodeposited film for fabricating suitable semiconductor film fitting for various applications. In this work, the morphological and compositional properties of electrodeposited delafossite CuFeO2 film, according to the deposition parameters, were studied. The CuFeO2 film was fabricated by the galvanostatic electrodeposition and post-annealing process under inert gas flow. The type of solvent, electrolyte condition, applied current density and deposition time were controlled as the variable deposition parameters. As a result, the typical CuFeO2 film, without any impurities, was electrodeposited in the electrolyte-based DMSO solvent. Interestingly, the concentration of potassium perchlorate as a complexing agent caused morphological change in electrodeposited CuFeO2 film, as well as compositional transition. On the other hand, the applied current density and deposition time only influenced the morphology of electrodeposited CuFeO2 film. These observations would provide specific guidelines for the fabrication of electrodeposited CuFeO2 film with suitable composition and morphology for various applications.

Observation of spatter-induced stochastic lack-of-fusion in laser powder bed fusion using in situ process monitoring

Material produced via additive manufacturing (AM) continues to exhibit variable mechanical properties despite apparent optimization of processing parameters, inhibiting qualification efforts and limiting use in critical applications. Stochastic lack-of-fusion flaws may help explain this variability, but the origin of these seemingly random defects has to this point remained unclear. In this work, we show that spatter particles, material ejected from the laser melt pool, are directly responsible for generating stochastic lack-of-fusion in laser-based powder bed fusion components through the application of spatial statistics. A statistically significant, causal relationship between spatter particles and stochastic lack-of-fusion is established, and the spatial and morphological relationships between spatter and internal flaws are investigated. The occurrence of spatter-induced lack-of-fusion in relation to the inert gas flow and laser trajectory direction is also investigated, and recommendations for mitigating the occurrence of spatter are evaluated.

Analysis of technological processes of production of spherical powders and granules of NiAl nickel monoaluminide for the needs of domestic engine building

The article is devoted to the study of the features of various methods for obtaining granules of nickel aluminide NiAl. The problems hindering the widespread use of nickel aluminide NiAl in modern aircraft and engine construction are analyzed. It has been revealed that the main problems hindering the widespread industrial use of nickel aluminide NiAl are practically zero plasticity of the material during pressure treatment and difficulties in machining parts made of this material. However, this problem can be solved with the use of pellet metallurgy technologies, when by sintering the granular material, an almost finished product is obtained that requires minimal amounts of subsequent machining. Within the framework of the conducted studies, the quality criteria of the obtained granules were determined, which include the sphericity of the granules, the stability of the obtained dimensions of the granular material, the absence of defects in the form of pores, the absence of satellites on the surface of the granules, the presence of a finely dispersed dendritic structure of the granule material. Several methods of obtaining granules of nickel aluminide NiAl have been investigated from the point of view of obtaining the highest quality raw materials, namely: the method of spraying the melted billet with a high-temperature inert gas flow (gas atomization method), the method of centrifugal spraying of the melted electrode (PREP method), the method of centrifugation of the melt using a perforated crucible. It is determined that the optimal way to obtain a high-quality granulate of NiAl material is the method of centrifugal spraying of the melted electrode. In the course of the conducted research, it was proved that the main parameter of the process of centrifugal spraying of the melted electrode, affecting the quality of the obtained granules, their diameter and the value of the dendritic parameter of the microstructure of the granules, is not so much the current strength I as the rotation speed of the melted electrode n. The optimal values of the electrode rotation speeds are determined, which are n ≈ 15000-16000 revolutions per minute at a current strength I ≈ 1000-1500 A. A technology for obtaining high-quality NiAl material granulate has been developed and tested, which includes operations for obtaining initial NiAl blanks by self-propagating high-temperature synthesis, subsequent remelting of semi-finished products, heat treatment, separation of granules and subsequent granulation by the PREP method.

Using Physical Modeling to Optimize the Aluminium Refining Process.

Concern for the environment and rational management of resources requires the development of recoverable methods of obtaining metallic materials. This also applies to the production of aluminium and its alloys. The quality requirements of the market drive aluminium producers to use effective refining methods, and one of the most commonly used is blowing an inert gas into liquid aluminium via a rotating impeller. The efficiency and cost of this treatment depends largely on the application of the correct ratios between the basic parameters of the process, which are the flow rate of the inert gas, the speed of the rotor and the duration of the process. Determining these ratios in production conditions is expensive and difficult. This article presents the results of research aimed at determining the optimal ratio of the inert gas flow rate to the rotary impeller speed, using physical modeling techniques for the rotor as used in industrial conditions. The tests were carried out for rotary impeller speeds from 150 to 550 rpm and gas flow rates of 12, 17 and 22 dm3/min. The research was carried out on a 1:1 scale physical model, and the results, in the form of visualization of the degree of gas-bubble dispersion, were assessed on the basis of the five typical dispersion patterns. The removal of oxygen from water was carried out analogously to the process of removing hydrogen from aluminium. The curves of the rate of oxygen removal from the model liquid were determined, showing the course of oxygen reduction during refining with the same inert gas flows and rotor speeds mentioned above.

Sorption of Mercury in Batch and Fixed-Bed Column System on Hydrochar Obtained from Apple Pomace

This paper presents the methodology for the preparation of hydrochar obtained from waste materials of natural origin and investigates its applicability for removing mercury ions from aqueous systems. The sorption properties of the obtained hydrochar were investigated in a batch and in a flow-through column system. The hydrochar material was obtained from apple pomace, which was hydrothermally carbonized in 230 °C for 5 h in a hydrothermal reactor. The hydrochar formed in the process was thermally activated with an inert gas flow—CO2. Obtained materials were characterised with XRD, FTIR-ATR, SEM-EDS and nitrogen sorption (BET) analyses, which confirmed the obtaining of a highly porous carbon material with a specific surface area of 145.72 m2/g and an average pore diameter of 1.93 nm. The obtained hydrochar was analysed for sorption of mercury ions from aqueous solutions. Equilibrium isotherms (Langmuir, Freundlich, Dubinin–Radushkevich, Temkin, Hill, Redlich-Peterson, Sips and Toth) and kinetic models (pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion) were determined. The sorption process of mercury on the obtained material is best described using the Freundlich isotherm and a pseudo-second-order kinetic model. This indicates that the process is chemical in nature The sorption of mercury ions from an aqueous solution with a concentration of C0 = 100 mg Hg/dm3 has been also carried out in a flow-through column system. The data obtained from adsorption were fitted to mathematical dynamic models (Bohart–Adams, Thomas, Yoon–Nelson, Clark, BDST and Yan) to illustrate the bed breakthrough curves and to determine the characteristic column parameters. The Yan model has the best fit across the study area, although the Thomas model better predicts the maximum capacity of the bed, which is qmax = 111.5 mg/g.

Self‐Aligning Metallic Vertical Interconnect Access Formation through Microlensing Gas Phase Electrodeposition controlling Airgap and Morphology

AbstractThis publication reports self‐aligning metallic via microlensing gas phase electrodeposition formation. Key operational parameters to fabricate vertical ruthenium and rhodium interconnects (via) with a diameter of 100 nm are discussed. Moreover, airgaps are implemented during the deposition process, which utilizes spark discharge to generate a flux of charged nanoparticles. An inert gas flow transports the nanoparticles through a reactor chamber close to the target substrate. The substrate uses a pre‐patterned resist with openings to a silicon/silicon dioxide/metal stack to direct the deposition of the nanoparticles to form localized self‐aligning vertical interconnects. Five process parameters were identified, which impact the morphology and conductance of the resulting interconnects: spark discharge power, gas flow rate, microlens via dimensions, substrate surface potential, and in situ flash lamp power. This parameter set enables a controlled adjustment of the via interconnect morphology and its minimum feature size. Gas flow rate in combination with spark discharge power contribute significantly to the morphology of the interconnect. Spark power and microlens via dimensions have the largest influence on the surface potential of the insulating resist cover, which enables a localized microlensing gas phase electrodeposition of a via with a controlled ratio between conducting diameter and airgap.

Enhancement of mass transfer performance by nanoparticles during the CO2 absorption with MDEA solution in a randomly packed tower

AbstractIn this study, the mass transfer enhancement by nanoparticles during CO2 absorption process with MDEA solution in a randomly packed tower was investigated. The mass transfer performance of MDEA solution with and without nanoparticles were quantified and analyzed in terms of the volumetric overall mass transfer coefficient (KGav). An enhancement factor (E), defined as the ratio of KGav with and without nanoparticles, was further introduced to evaluate the enhancement effect of the addition of nanoparticles. The effects of TiO2 nanoparticle concentration, MDEA concentration, liquid flow rate, liquid temperature, inert gas flow rate, and CO2 loading on KGav and E were systematically studied in the packed tower. It is found that the maximum value of E can reach 1.37, when the nanoparticle concentration is 0.09wt%, the liquid flow rate is 21.22 m3/m2·h, the liquid temperature is 27°C, the MDEA concentration is 30%, the gas flow rate is 7.58 kmol/m2·h and the CO2 loading is 0.2 mol CO2/mol MDEA. Usually, the KGav of the MDEA nanofluids can be increased by 10–37% in a randomly packed tower compared to that of the MDEA solution, which is consistent with the results from the bubbling reactors. However, when the CO2 loading of absorption exceeds 50%, E becomes less than 1.0, which means that high CO2 loading inhibits the enhancement effect of nanoparticles. In order to predict the mass transfer performance of MDEA nanofluid, a formula correlating E and various dimensionless operating parameters (i.e. , , and ) is proposed and fitted with an average absolute deviation of 14%. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.

Experimental evidence of gas-mediated heat transfer in porous solids measured by the flash method

Laser/light flash analysis (LFA) is becoming an increasingly popular assessment tool for the thermal properties of porous samples. Elevated temperature measurements are typically conducted under a protective atmosphere; specifically, under inert gas flow. Immersing a sample with interconnected porosity in a gas environment theoretically allows heat transfer via gas conduction or convection. To prove that LFA measurements are affected by the choice of the gas environment, measurements are conducted under inert gas flow (helium and nitrogen), static inert gas (nitrogen) and vacuum with two different instruments and two sets of samples: highly-conductive alloy foams and insulating lightweight concrete. A heat conduction model accounting for light penetration was used to extract the apparent thermal diffusivity of the solid–gas mixture. A correlation between the Biot number and the conductivity of the gas environment was registered. This is unusual for an LFA experiment where radiative heat losses, which are independent of the gas environment, are typically considered to be dominant. At the same time, variations in either the microgeometry of the porous sample or the type of carrier gas produce a systematic change in the shape of the time–temperature profiles and the duration of the temperature transient. In lightweight concrete samples, switching the instrument to helium flow enables a multifold increase in the apparent thermal diffusivity relative to the measurements done under vacuum. An attempt to explain this variation was made with a two-temperature model of coupled solid–gas conduction. It is argued that an additional factor is missing from the analysis.

Architecture of bimetallic-MOF/silicate derived Co/NC@mSiO2 as peroxymonosulfate activator for highly efficient ciprofloxacin degradation

Bimetallic-ZIF@silicate derived Co/NC@mSiO2 hollow sphere was developed as an excellent peroxymonosulfate (PMS) activator for ciprofloxacin (CFL) antibiotic and parabens degradation. First, bimetallic Zn-Co/ZIF frameworks were prepared by a solvothermal method and then coated with a silica layer. Subsequently, Zn-Co/ZIF@mSiO2 was carbonized under nitrogen gas to obtain the Co, N co-doped porous carbon material. The evaporation of zinc metal in Zn-Co/ZIF@mSiO2 by inert gas flow played an important role in the formation of porous carbon material. In the presence of a small quantity of PMS, this hollow sphere material acts as a highly efficient catalyst for the degradation of CFL with a rate constant of 0.07 min−1. The findings obtained from the quenching radical test and electron paramagnetic resonance (EPR) reveal that Co site within the hollow sphere nanoreactor catalyzed PMS to the generation of the HO, SO4−, and 1O2 for CFL degradation. Notably, the presence of Co NPs in the hollow sphere material enables the facile separation of the catalyst from the reaction mixtures using an external magnet. Furthermore, the as-prepared catalysts exhibited antibacterial activity in Staphylococcus aureus (S. aureus). The current study provides new horizons to develop ZIF-derived hybrid hollow materials in eliminating organic pollutants.

Interpretation of combustion properties of raw-pyrolyzed lignite with kinetic data

ABSTRACT This study investigated the pyrolysis properties and kinetic behavior of Ermenek (Konya, Turkey) lignite. For this purpose, lignite was carbonized at 500°C and different heating rates (5, 10, 15, and 20°C/min). Proximate, elemental, XRF, and TGA-DTA lignite and chars were performed. Thermal analyses were performed at a heating rate of 10°C/min from room temperature to 1000°C and an inert (N2) gas flow of 50 ml/min. Peak temperatures and mass losses were determined from the data obtained from the experiments. By examining the thermogram curves, three different temperature regions depended on moisture loss, the release of volatile matter, and fixed carbon combustion. In addition, from these data, kinetic calculations were performed using Arrhenius and Coats-Redfern approaches, and the apparent activation energies were calculated for each region. The activation energy values calculated according to the Coats-Redfern kinetic model are significantly lower than those calculated according to the Arrhenius kinetic model. The highest activation energies calculated were: for Region 1 and Region 2 at 5°C/min heating rate and for Region 3 at 10°C/min heating rate.

Optimization of process parameters of Lagerstroemia speciosa seed hull pyrolysis using a combined approach of Response Surface Methodology (RSM) and Artificial Neural Network (ANN) for renewable fuel production

The present study addressed the valorization of Lagerstroemia speciosa seed hull (LS) biomass for the production of renewable fuel and chemicals via pyrolysis. Important pyrolysis parameters such as heating rate (H.R), temperature, and inert gas (N2) flow rate were optimized using the joint approach of Response Surface Methodology (RSM) and Artificial Neural Network (ANN). Results showed comparatively higher R2 and lower MSE value for ANN model than RSM. The experimental findings revealed that the optimum condition for the maximum bio-oil yield (45.6%) was: temperature = 550 °C, H.R = 65 °C/min, and N2 flow rate = 60 ml/min; however, at this condition, the predicted bio-oil yield using RSM and ANN was 44.98 and 45.10% respectively. The obtained bio-oil was characterized based on its physicochemical properties such as GCMS, FTIR, and 1H NMR. The current work provides an insight by combining both RSM and ANN modeling methodologies to get a more efficient way to process modeling.

Combined Activated Carbon with Spent Fluid Catalytic Cracking Catalyst and MgO for the Catalytic Conversion of Waste Polyethylene Wax into Diesel-like Hydrocarbon Fuels.

Catalytic pyrolysis of polymer waste is an attractive alternative process for the conversion of large hydrocarbon compounds to useful products for the most reliable fueling and valuable chemicals, growing toward a circular economy and enhancing the reduction of waste materials. In this study, catalytic pyrolysis of waste polyethylene wax (WPEW) using a dual acid–acid catalyst and acid–base catalyst, which had various pore size distributions and included a strong active site, maximized the desirable yield and product distribution. The effect of the process conditions and synergy of activated carbon (AC) blended into both a spent fluid catalytic cracking catalyst (FCC) and magnesium oxide (MgO) catalyst was examined in a 3000 cm3 custom-built reactor at varying operating temperatures (400–470 °C), inert nitrogen gas flow rates (50 mL min–1), catalyst loading (1–5 wt %), and FCC-AC and MgO-AC ratios in the catalytic conversion of WPEW to obtain the highest amount of diesel-like oil. The results indicated that thermal cracking of WPEW at 420 °C by a fixed inert N2 flow rate of 50 mL min–1 obtained the highest liquid yield of 81.64 wt % and a diesel-like fraction of 35.51 wt %, while the catalytic conversion of WPEW under optimum conditions (temperature: 420 °C; fixed inert N2 flow rate: 50 mL min–1; catalyst load: 5 wt %; MgO-AC ratio: 0.5:0.5) achieved the highest liquid diesel-like yield of 41.92 wt %. Physicochemical analyses showed that the highest heating value of WPEW pyrolytic oil was 44.20 MJ kg–1, and the viscosity was 1.7 mm2 s–1 at 40 °C. The combination of MgO-AC as a dual catalyst illustrates a positive synergistic effect on the catalytic activity performance markedly, outstanding catalytic characteristics alongside high selectivity in pyrolysis of WPEW to paraffinic hydrocarbons in the diesel-like fraction.

Impact strength and structural refinement of A380 aluminum alloy produced through gas-induced semi-solid process and Sr addition

Semi-solid processing of A380 aluminum alloy was performed by gas induced semi-solid (GISS) process. The effects of argon inert gas flow rate, starting temperature and duration of gas purging as key GISS parameters and also modification with Sr on the structural refinements, hardness and impact strength of GISS alloys were investigated. Microstructural evolution shows that there is an important effect of the pouring temperature and Sr addition on the morphology and size of primary α(A1) in the alloy to change from coarse dendritic to fine globular structure. The best sample which has fine grains of 51.18 μm in average size and a high level of globularity of 0.89 is achieved from a GISS processing of Sr modified alloy in which the gas purging started at 610 °C. The impact strength of the GISS optimized samples ((4.67±0.18) J/cm2) shows an increase of about 40% with respect to the as-cast sample due to the globular structure and fibrous Si morphology. Moreover, the hardness of the optimized GISS sample ((89.34±2.85) HB) increases to (93.84±3.14) HB by modification with the Sr and GISS process. The fracture surface of Sr modified alloy is also dominated by complex topography showing typical ductile fracture features.