Honey bees find the shortest path: a collective flow-mediated approach

Artificial Life and Robotics - Honey bees (Apis mellifera L.) are social insects that makes frequent use of volatile pheromone signals to collectively navigate unpredictable and unknown...     

A method to determine resin flow during curing of composite laminates

An experimental method is presented to determine the amount of resin flow within a composite laminate during cure. The method is analogous to the use of radioactive tracers in other applications. Heavier elements such as chlorine and bromine, which may be naturally present in small amounts in epoxy resins are used to follow resin flow and mixing. The presence and the quantity of these “tags” is determined using wavelength dispersive X-ray analysis in a scanning electron microscope. With the resins in this study, it is shown that it is possible to measure volume fractions of resin with accuracies ranging from ±0.5 to ±3 volume %. By using brominated resin in only one layer of a laminate, the degree of flow and mixing can be followed accurately. The results suggest that there is considerable resin mixing as well as flow.     

(MnzFe1—z)yOx combined oxides as oxygen carrier for chemical‐looping with oxygen uncoupling

Oxygen carrier particles with the composition (Mn_0.8,Fe_0.2)₂O₃ were found to readily release gas phase oxygen at 850°C, and were capable to oxidize CH₄ completely and convert wood char rapidly to CO₂ during experiments in a batch fluidized bed reactor. The particles were able to release oxygen corresponding to more than 3% of their mass in less than 40 s. Because of the low price and favourable environmental properties of manganese and iron oxides, this finding could be of great importance for the development of chemical‐looping combustion with oxygen uncoupling. © 2012 American Institute of Chemical Engineers AIChE J, 59: 582–588, 2013     

Production and examination of oxygen‐carrier materials based on manganese ores and Ca(OH)2 in chemical looping with oxygen uncoupling

This study concerns production of oxygen‐carrier particles using six different manganese ores. The ores were made to react with Ca(OH)₂ at elevated temperature, forming calcium manganite. The method utilized to manufacture particles was extrusion. Methane and syngas conversion and oxygen release of the samples in inert atmosphere were investigated. The oxygen carrier based on South African (B) manganese ore, showed good methane conversion and was able to transfer oxygen corresponding to 1.5% of its mass during reduction with gaseous fuel. All examined oxygen carriers were capable of converting syngas completely. The ability to release gaseous oxygen was examined by adding wood char in a stream of nitrogen for four selected samples sintered at 1300°C/6 h. These samples released an amount of oxygen corresponding to 0.37–0.68% of their mass. The reactivity of all the ores was improved after the proposed treatments. Reactivity results of the oxygen carrier made from South African (B) ore and Ca(OH)₂, sintered at 1300°C for 6 h were the most promising. Attrition measurements with a jet cup of the oxygen carriers sintered at 1300°C/6 h showed that all the samples made from ores were at least three times more resistant to mechanical attrition compared to particles made from synthetic Mn₂O₃. Producing feasible oxygen carriers directly from ores could potentially cut the cost of chemical looping with oxygen uncoupling and have a significant impact on its competitiveness among other carbon capture technologies. © 2013 American Institute of Chemical Engineers AIChE J 60: 645–656, 2014     

Hybrid Nanoarchitectonics of Chitosan-Cerium Oxide Nanoparticles for Anticancer Potentials

The aim of this study was to synthesize green cerium oxide nanoparticles (CeO₂–NPs) and coat them with chitosan polymers to increase bioavailability and their effectiveness in anti-cancer studies. For the synthesis of CeO₂–NPs, aqueous rosemary leaf extract (RLE) was used as a reducing and stabilizing agent, and after characterizing the nanoparticles (DLS and XRD), a coating of chitosan around the nanoparticles (CeCh–NPs) was created by ionic gelation method. After characterizing (DLS, Zeta potential, FTIR and FESEM) and confirming the presence of nanoparticles, its toxicity effects were evaluated by MTT method and its pro-apoptotic effects were evaluated by qPCR (Caspase 3 and 9) and flow cytometric analysis. CeO₂–NPs were formed with uniform dispersion (PDI: 0.25) in nanometer dimensions (184.84 nm) and after coating, their size increase to 202.35 nm was confirmed by DLS method. The CeCh–NPs were spherical, stable (ζ potential:?+?35.4 mV) and uniformly dispersed (PDI: 0.27). The median concentrations of nanoparticles against AGS, A459, PC3 and HFF cells were reported to be about 156.02, 169.1, 155.8 and 307.5 μg/ml. Increased expression of caspase 3 and 9 genes as well as increased percentage of SubG1 phase cells in flow cytometry confirmed the occurrence of apoptosis in treated cells. The results of this study confirmed the anticancer properties of CeCh–NPs by relying on the apoptosis process.

     

On the high‐gasification rate of Brazilian manganese ore in chemical‐looping combustion (CLC) for solid fuels

The high rate of char gasification observed when using a Brazilian manganese ore as compared to ilmenite is investigated in a batch fluidized‐bed reactor. Experiments were carried out at 970°C using petroleum coke, coal and wood char as fuel with a 50% H₂O in N₂ as fluidizing gas. A manufactured manganese oxygen carrier was also used, however, which presented a slower char conversion rate than the manganese ore. It is concluded that decrease in H₂ inhibition and oxygen release are unlikely to be the main responsible mechanisms for the ore's unexpected gasification rate. The ore was also mixed in different ratios with ilmenite and it was observed that the presence of even small amounts of ore in the bed resulted in increased gasification rate. Thus, the high‐gasification rate for the manganese ore could be due to a contribution from the impurities in the ore by catalyzing the gasification reaction. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4346–4354, 2013