Pyrolysis of Automotive Shredder Residue (ASR): Thermogravimetry, In-Situ Synchrotron IR and Gas-Phase IR of Polymeric Components

This article reports the characterisation of pyrolysis of automotive shredder residue using in situ synchrotron IR, gas-phase IR, and thermal analyses to explore if the automotive shredder residue can be converted into value-added products. When heating to ~600 °C at different heating rates, thermal analyses suggested one- to two-stage pyrolysis. Transformations in the first stage, at lower temperatures, were attributed to the degradation of carbonyl, hydroxyl, or carboxyl functional stabilisers (aldehyde and ether impurities, additives, and stabilisers in the ASR). The second stage transformations, at higher temperatures, were attributed to the thermal degradation of the polymer char. Simultaneous thermal analyses and gas-phase IR spectroscopy confirmed the evolution of the gases (alkanes (CH4), CO2, and moisture). The synchrotron IR data have demonstrated that a high heating rate (such as 150 °C/min) results in an incomplete conversion of ASRs unless sufficient time is provided. The thermogravimetry data fit the linearised multistage kinetic model at different heating rates. The activation energy of reactions varied between 24.98 and 124.94 kJ/mol, indicating a surface-controlled reaction exhibiting high activation energy during the initial stages and a diffusion and mass transfer control showing lower activation energy at the final stages. The corresponding frequency factors were in the range of 3.34 × 1013-5.68 × 101 mg-1/min for different pyrolysis stages. The evolution of the functional groups decreased with an increase in the heating rate.

Metarhizium indicum, a new species of entomopathogenic fungus infecting leafhopper, Busoniomimus manjunathi from India

A new species of entomopathogenic fungus, Metarhizium indicum, which derives its species epithet after its Indian origin is reported here. The fungus was found to cause natural epizootics in leafhopper (Busoniomimus manjunathi) infesting Garcinia gummi-gutta (Malabar tamarind), an evergreen spice tree native to South and Southeast Asia, known for its use as a culinary flavourant, dietary supplement and traditional remedy for various human ailments. The fungus was found to cause more than 60% mortality in field collected insects. The identity of the new species was established based on its distinct morphological characteristics and multi-gene sequence data analyses. Phylogenetic analyses using internal transcribed spacer region (ITS), DNA lyase (APN2) and a concatenated set of four marker genes [translation elongation factor 1-alpha (TEF), β-tubulin (BTUB), RNA polymerase II largest subunit (RPB1) and RNA polymerase II second largest subunit (RPB2)] along with marked differences in nucleotide composition and genetic distance unambiguously support our claim that the present fungus infecting leafhoppers is a new addition to the genus Metarhizium.

Decarbonising the Portland and other Cements-Via Simultaneous Feedstock Recycling and Carbon Conversions Sans External Catalysts

The current overarching global environmental crisis relates to high carbon footprint in cement production, waste plastic accumulation, and growing future energy demands. A simultaneous solution to the above crises was examined in this work. The present study focused on decarbonizing the calcination process of the cement making using waste plastics and biowastes as the reactants or the feedstock, to reduce the carbon footprint and to simultaneously convert it into clean energy, which were never reported before. Other studies reported the use of waste plastics and biowastes as fuel in cement kilns, applicable to the entire cement making process. Calcination of calcium carbonate and magnesium carbonate is the most emission intensive process in cement making in Portland cements and Novacem-like cements. In the Novacem process, which is based on magnesium oxide and magnesium carbonates systems, the carbon dioxide generated is recycled to carbonate magnesium silicates at elevated temperatures and pressures. The present study examined the Novacem-like cement system but in the presence of waste plastics and biomass during the calcination. The carbon dioxide and the methane produced during calcination were converted into syngas or hydrogen in Novacem-like cements. It was established that carbon dioxide and methane emissions were reduced by approximately 99% when plastics and biowastes were added as additives or feedstock during the calcination, which were converted into syngas and/or hydrogen. The reaction intermediates of calcination reactions (calcium carbonate–calcium oxide or magnesium carbonate–magnesium oxide systems) can facilitate the endothermic carbon conversion reactions to syngas or hydrogen acting as non-soot forming catalysts. The conventional catalysts used in carbon conversion reactions are expensive and susceptible to carbon fouling. Two criteria were established in this study: first, to reduce the carbon dioxide/methane emissions during calcination; second, to simultaneously convert the carbon dioxide and methane to hydrogen. Reduction and conversion of carbon dioxide and methane emissions were facilitated by co-gasification of plastics and bio-wastes.

Characterization and biocontrol potential of a naturally occurring isolate of Metarhizium pingshaense infecting Conogethes punctiferalis

An entomopathogenic fungus was isolated from an infected larva of Conogethes punctiferalis (Guenée) (Crambidae: Lepidoptera), a highly polyphagous pest recorded from more than 120 plants and widely distributed in Asia and Oceanic countries. The fungus was identified as Metarhizium pingshaense Q.T. Chen & H.L. Guo (Ascomycota: Hypocreales) based on morphological characteristics and molecular studies. Scanning electron microscopic studies were conducted to study the infection of C. punctiferalis by M. pingshaense. Bioassay studies with purified conidial suspension proved that the isolate was highly virulent to C. punctiferalis, causing more than 86 % mortality to fifth instar larvae at 1 × 10⁸ spores/mL, under laboratory conditions. The median lethal concentration (LC₅₀) of the fungus against late instar larvae was 9.1 × 10⁵ conidia/mL and the median survival time (MST) of late instar larvae tested at the doses of 1 × 10⁸ and 1 × 10⁷ conidia/mL were 4.7 and 6.4 days, respectively. The optimal temperature for fungal growth and sporulation was found to be 25 ± 1 °C. This is the first report of M. pingshaense naturally infecting C. punctiferalis. Isolation of a highly virulent strain of this fungus holds promise towards development of a potential mycoinsecticide against this pest.

Plastics-Villain or Hero? Polymers and Recycled Polymers in Mineral and Metallurgical Processing-A Review

This review focusses on the use of recycled and virgin polymers in mineral and metallurgical processing, both high and ambient temperature processes, including novel applications. End of life applications of polymers as well as the utilisation of polymers during its life time in various applications are explored. The discussion includes applications in cleaner coal production, iron and steel production, iron ore palletisation, iron alloy manufacturing, manganese processing, E-wastes processing and carbon sequestration. The underlying principles of these applications are also explained. Advantages and disadvantages of using these polymers in terms of energy and emission reductions, reduction in non-renewables and dematerialisation are discussed. Influence of the polymers on controlling the evolution of micro and nanostructures in alloys and advanced materials is also considered.

Effect of Electron Beam Radiolysis on Mechanical Properties of High Performance Polyimides. A Comparative Study of Transparent Polymer Films

The mechanical properties of four optically transparent polyimides prepared from the dianhydrides ODPA and 6FDA and the diamines ODA and DAB were assessed. The property changes when these polymers are subjected to high-energy electron-beam irradiation (1 MeV) for doses up to 18.5 MGy and temperatures up to 523 K were also studied and compared. The corresponding changes on radiolysis of Kapton are reported for comparison with the other polymers. The tensile properties of the four polyimides differed mainly by the nature of the dianhydride, with the ODPA polymers undergoing necking and cold drawing and the 6FDA polymers brittle fracture. The four polyimides were synthesized with the objective of obtaining optimum transparency for space applications where high-energy radiation doses of 15-20 MGy may be expected in geosynchronous orbits over a life span of 20 years. The polyimides were shown to maintain good optical and tensile properties at temperatures up to about 450 K for a dose of 18.5 MGy, but above this temperature the moduli of the polymers began to deteriorate and there was a small decrease in the transmittance of the exposed polymer films.

G -Values for Scission and Crosslinking on γ — Radiolysis of Ultem at 303 K

The radiation chemical yields G( S) and G( X) for H-linking and Y-linking models for Ultem have been calculated from molecular weight analysis by gel permeation chromatography. These G-values have been compared with the G-values obtained from analysis of soluble fractions above the gel dose, which have been reported in previous works. An analysis of the molecular weight data in terms of H-linking and Y-linking mechanisms yielded values of G( S H) = 1.0 × 10−3 and G( H) = 6.0 × 10−3 and G( S Y) = 1.3 × 10−2 and G( Y) = 1.8 × 10−2. The corresponding values obtained from the solubility data were G( S H) = 0.53 × 10−2, G( H) = 1.39 × 10−2, G( S Y) = 4.2 × 10−2 and G( Y) = 4.6 × 10−2. The origin of the disagreement between the molecular weight and solubility values is not clear, but it could arise as a result of observed microgel formation below the reported gel dose of 0.13 MGy. Whether the crosslink mechanism proceeds by an H-linking or Y-linking process is also unclear and will require direct observation of the crosslinking structures.

Proprioceptive changes in the contralateral knee joint following anterior cruciate injury

Loss of proprioception following an anterior cruciate ligament (ACL) injury has been well documented. We evaluated proprioception in both the injured and the uninjured limb in 25 patients with ACL injury and in 25 healthy controls, as assessed by joint position sense (JPS), the threshold for the detection of passive movement (TDPM) and postural sway during single-limb stance on a force plate. There were significant proprioceptive deficits in both ACL-deficient and uninjured knees compared with control knees, as assessed by the angle reproduction test (on JPS) and postural sway on single limb stance. The degree of loss of proprioception in the ACL-deficient knee and the unaffected contralateral knee joint in the same patient was similar. The TDPM in the injured knee was significantly higher than that of controls at 30° and 70° of flexion. The TDPM of the contralateral knee joint was not significantly different from that in controls. Based on these findings, the effect of proprioceptive training of the contralateral uninjured knee should be explored.