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•Catalytic pyrolysis of wood plastic composite was investigated.•In-situ catalytic pyrolysis produce the larger amount of aromatics than ex-situ reaction.•Aromatics formation was ...hindered by the use of small pore HZSM-5.•Coke formation was increased over large pore HY.
The catalytic pyrolysis of commercial wood plastic composite (WPC) over microporous catalysts was investigated by thermogravimetric (TG) analysis and tandem micro reactor-gas chromatography/mass spectrometry (TMR-GC/MS). The non-isothermal TG analysis results showed that the decomposition temperatures of polyethylene and polypropylene in the WPC were shifted to lower temperatures by the use of catalysts, from 484 °C to 440 °C over HY(5.1), 457 °C over HBeta(25), and 469 °C over HZSM-5. TMR-GC/MS indicated that the formation efficiency of aromatic hydrocarbons during the catalytic pyrolysis of WPC was affected not only by the catalyst properties, but also by the contact mode between the WPC and catalyst. The in-situ catalytic pyrolysis of WPC showed a higher aromatic formation efficiency than the ex-situ reaction because of the sufficient likelihood of a reaction between the reactant molecules and catalysts during the in-situ reaction. Among the catalysts, HBeta produced the largest amount of aromatics followed by HZSM-5 and HY. Diffusion hindering of the reactant molecules to the small pores of HZSM-5 and the large amount of coke inside the large pores of HY were the main reasons for the lower aromatic formation efficiency over HZSM-5 and HY than over HBeta. Sequential catalytic TMR-GC/MS showed that the increased diffusion hindering effect caused by coke accumulation is the main limitation on the use of HZSM-5. Mesoporous HZSM-5 may be a potential way of overcoming the limitation of the catalysts used in this study.
•Hierarchical zeolites is applied to the catalytic pyrolysis of wood polymer composites.•Hierarchical ZSM-5 with high mesoporosity and high acidity produced larger aromatics than ZSM-5.•Mass transfer ...of wood polymer composite having higher polypropylene content was hindered at 500 °C.
Hierarchical zeolites have superior catalytic properties over purely microporous zeolites, leading to the enhanced diffusivity of molecules and strong acidity of the catalyst. In this study, hierarchical desilicated mesoporous ZSM-5 and Beta were prepared by the desilication of commercial microporous zeolites and applied to the catalytic pyrolysis of wood polymer composites. Hierarchical desilicated mesoporous ZSM-5 and Beta showed the typical X-ray diffraction patterns of microporous ZSM-5 and Beta with higher mesoporosity compared to the parent materials. The activity of the desilicated zeolites for the catalytic pyrolysis of wood polymer composites was evaluated using a thermogravimetric analysis and tandem micro reactor-gas chromatography/mass spectrometry. Among the catalysts tested, the lowest decomposition temperatures of wood polymer composites were observed using hierarchical desilicated mesoporous Beta followed by hierarchical desilicated mesoporous ZSM-5 and ZSM-5. This trend correlated well with the mesoporosity of the catalysts. The formation efficiency of hierarchical desilicated mesoporous ZSM-5 was highest followed by microporous ZSM-5, hierarchical desilicated mesoporous Beta, and Beta, indicating that in addition to mesoporosity, the shape selectivity induced by microporosity and strong acidity are important for the aromatization of pyrolysis vapors. In addition, the aromatic formation efficiency of the catalysts differed according to the properties of wood polymer composites. Compared to wood polymer composite 2, wood polymer composite 1 produced a larger quantity of aromatics during catalytic pyrolysis over all the catalysts at 500 °C owing to its higher polyethylene content. Both wood polymer composites exhibited a similar aromatic formation efficiency during catalytic pyrolysis at 600 °C because the diffusion hindering effect of polypropylene molecules to the catalyst pores was lower at the higher temperature.
ZnO and Aluminum doped ZnO nanoparticles (Al/ZnO NPs) were successfully synthesized by the sol-gel method. Together with the effect of calcination temperatures (200, 300 and 400 °C) and Al dosage ...(1%, 3%, 5% and 10%) on structural, morphological and optical properties of Al/ZnO NPs, their photocatalytic degradation of methyl orange (MO) dye was investigated. The calcination temperatures at 200, 300 and 400 °C in forming structure of ZnO NPs led to spherical nanoparticle, nanorod and nanoflake structures with a well-crystalline hexagonal wurtzite, respectively. The ZnO NPs calcined at 200 °C exhibited the highest specific surface area and light absorption property, leading to the MO removal efficiency of 80% after 4 h under the Ultraviolet (UV) light irradiation. The MO removal efficiency was approximately two times higher than the nanoparticles calcined at 400 °C. Furthermore, the 5% Al/ZnO NPs exhibited superior MO removal efficiency of 99% in only 40 min which was approximately 20 times enhancement in photocatalytic activity compared to pristine ZnO under the visible light irradiation. This high degradation performance was attributed to the extended light absorption, narrowed band gap and effective suppression of electron-hole recombination through an addition of Al metal.
Achieving strong filler/matrix interactions is essential in the design and manufacturing of composite systems. Molecular dynamics simulation has played a vital role in the investigation of ...interfacial behavior by predicting the mechanical properties of polymer-based composites. There has been, however, a big gap for clearly establishing a correlation between simulations and experiments because of limitations in size and time scale. Herein, a comparative analysis on the interfacial adhesion behavior of the short glass fiber and dental resin matrix is performed combining the atomistic simulations and single fiber/microdroplet pull-out tests in micro-scale. The interfacial shear strength is measured at the molecular level by applying the scale factor on the glass fiber, and the simulations are compared with the experimental results of the pull-out tests. The enhanced reinforcement effects induced by the surface modification via silane coupling agents grafting on the glass fibers are verified in both studies. Moreover, the mechanical properties and dynamic behavior of the dental composites under the longitudinal and transverse tension loadings are examined with quantifying the free volume changes. The findings of this research provide the optimized design guidelines to precisely predict the mechanical performances of the short fiber reinforced dental composites via molecular dynamics simulations and experiments.
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•Desilication increased the acidity and mesoporosity of parent HZSM-5.•Desilicated HZSM-5 decreased activation energy of polystyrene decomposition than HZSM-5.•Desilicated HZSM-5 produced more ...valuable aromatics than HZSM-5.
Desilicated HZSM-5 (DeHZSM-5) was prepared by the desilication of HZSM-5 (SiO2/Al2O3: 30) and applied to the catalytic pyrolysis of polystyrene (PS) by thermogravimetric analysis (TGA) and pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS). TGA showed that HZSM-5 lowered the decomposition temperature and apparent activation energies of PS. DeHZSM-5 led a lower decomposition temperature and Ea values than HZSM-5. The main pyrolyzates of PS, styrene monomer, dimer, and trimer, were converted to smaller aromatic hydrocarbons, such as benzene and toluene. The increased pore size and acidity of DeHZSM-5 formed by the desilication of HZSM-5 led to the efficient diffusion of large molecular pyrolyzates with the increased formation of smaller molecular aromatic hydrocarbons confirming the higher catalytic cracking efficiency.
Despite widespread neural activity related to reward values, signals related to upcoming choice have not been clearly identified in the rodent brain. Here we examined neuronal activity in the lateral ...(AGl) and medial (AGm) agranular cortex, corresponding to the primary and secondary motor cortex, respectively, in rats performing a dynamic foraging task. Choice signals, before behavioral manifestation of the rat's choice, arose in the AGm earlier than in any other areas of the rat brain previously studied under free-choice conditions. The AGm also conveyed neural signals for decision value and chosen value. By contrast, upcoming choice signals arose later, and value signals were weaker, in the AGl. We also found that AGm lesions made the rats' choices less dependent on dynamically updated values. These results suggest that rodent secondary motor cortex might be uniquely involved in both representing and reading out value signals for flexible action selection.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
We investigated how different subregions of rodent prefrontal cortex contribute to value-based decision making, by comparing neural signals related to animal's choice, its outcome, and action value ...in orbitofrontal cortex (OFC) and medial prefrontal cortex (mPFC) of rats performing a dynamic two-armed bandit task. Neural signals for upcoming action selection arose in the mPFC, including the anterior cingulate cortex, only immediately before the behavioral manifestation of animal's choice, suggesting that rodent prefrontal cortex is not involved in advanced action planning. Both OFC and mPFC conveyed signals related to the animal's past choices and their outcomes over multiple trials, but neural signals for chosen value and reward prediction error were more prevalent in the OFC. Our results suggest that rodent OFC and mPFC serve distinct roles in value-based decision making and that the OFC plays a prominent role in updating the values of outcomes expected from chosen actions.
► Rat prefrontal cortex does not convey upcoming action selection signals ► Previous choice and outcome signals are broadly distributed in rat prefrontal cortex ► Orbitofrontal cortex encodes both positive and negative reward prediction errors ► Signals needed to update decision-making strategies converge in orbitofrontal cortex
RING finger protein 43 (RNF43) encodes the transmembrane E3 ubiquitin ligase, which targets the Wnt receptor Frizzled (FZD). RNF43 mutations have been discovered in various human cancers including ...colon, pancreatic, stomach, ovarian, and liver cancers. Functional studies on RNF43 missense mutations have shown that they negatively regulate Wnt signaling; however, there are few functional studies on RNF43 frameshift mutations. In this study, we showed that R117fs and P441fs mutants enhanced Wnt/β-catenin signaling, whereas Q409fs and G659fs mutants retained the ability to suppress Wnt/β-catenin signaling. Specifically, R117fs was unable to ubiquitinate FZD5 due to lack of the RING domain, although it was able to interact with FZD5. Immunofluorescence showed that R117fs failed to internalize FZD5 expressed on the cell surface. We also showed that LGK974, a potent Wnt inhibitor, decreased the Wnt/β-catenin activity by R117fs and P441fs mutations. Together, these results demonstrate that RNF43 frameshift mutations retain normal functionality; thus, targeted anti-cancer therapy can be developed according to the mutation type of RNF43.
Premature failure of armoured face conveyor (AFC) chains due to corrosion is a significant proportion of the unplanned downtime experienced on longwall equipment. The AFC chains are constantly in ...contact with water and wet coal. The premature failure issue of AFC chains has become more prominent since the introduction of longwall top-coal caving with its additional AFC. Reverse osmosis (RO) is a popular water treatment method for reducing salinity and dissolved solids, but its impact on the corrosion of the AFC chains is unclear. This study has been commissioned to investigate the direct effects of RO water on the corrosion of AFC chains. An immersion test was carried out using AFC chain steel submerged in two water samples: untreated dam water and treated water from an RO treatment plant. Elemental analysis was conducted for both water samples, and four corrosion indices were measured for both water samples. The RO water more vigorously dissolves calcium carbonate scales leading to increased corrosion of the AFC chains although the dam water has much higher levels of calcium, chloride, sulphate, sodium, and magnesium. Bicarbonate ions are the main alkaline factor of water that provides the buffering capacity to acids. Decreased alkalinity without balancing other ions in water causes high corrosivity and decreased scaling tendencies.
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