In this study, we investigate the Ar-40/Ar-39 systematics of nineteen diogenites thought to come from deep crustal levels of asteroid 4 Vesta. We applied both Electron Backscattered Diffraction (EBSD) and Ar-40/Ar-39 and methods to the unbrecciated diogenite LAP 031381. We obtained three plateau ages resulting in a combined weighted mean age of 4441 +/- 15 Ma (P = 0.16). The EBSD analyses suggest that LAP 031381 displays minimal evidence of shock and, when combined with petrography observations, diffusion modelling and Ar-40/Ar-39 data, these results suggest that the crustal volume that initially contained this diogenite, reached a temperature of ca. 630 degrees C at similar to 4.44 Ga. This corresponds to a linear cooling rate of similar to 5 degrees C / Ma for a crystallization age of 4550 Ma. Independent thermal models suggest that these conditions were present at a depth of 60 to 65 km at 4.44 Ga.The other eighteen diogenites yielded Ar-40/Ar-39 results that indicate that they have been variously shocked by impact events and seven of them yielded plateau ages ranging from 2413 +/- 189 Ma to 84 +/- 162 Ma. We combined these results with Ar-40/Ar-39 ages from eucrites and howardites and propose that the HED (Howardite, Eucrite, Diogenite) meteorites recorded impact events at the surface of Vesta until similar to 3.4 Ga when they were then ejected during a large collision. The eucrites, diogenites and howardites were then recombined into small rubble pile asteroids which probably make up a large part of the Vestoid family. After ejection, the K/Ar system in plagioclase crystals ceased in most cases to be fully reset by impact events as the temperature spikes reached during small impacts lack enough energy to trigger significant Ar-40* diffusion. On the other hand, ultra-transient and high-temperature - sensitive pyroxene crystals kept a more systematic record of small impacts until recent time. (38)Arc cosmochron cosmogenic exposure ages on diogenites mostly range from 51 +/- 7 Ma to 0 +/- 1 Ma and when combined with other HED cosmochron ages, suggest that almost all the HED meteorites were continuously ejected from secondary rubble pile asteroids mostly between 50 Ma and present.

Rubble piles asteroids consist of reassembled fragments from shattered monolithic asteroids and are much more abundant than previously thought in the solar system. Although monolithic asteroids that are a kilometer in diameter have been predicted to have a lifespan of few 100 million years, it is currently not known how durable rubble pile asteroids are. Here, we show that rubble pile asteroids can survive ambient solar system bombardment processes for extremely long periods and potentially 10 times longer than their monolith counterparts. We studied three regolith dust particles recovered by the Hayabusa space probe from the rubble pile asteroid 25143 Itokawa using electron backscatter diffraction, time-of-flight secondary ion mass spectrometry, atom probe tomography, and 40 Ar/ 39 Ar dating techniques. Our results show that the particles have only been affected by shock pressure of ca. 5 to 15 GPa. Two particles have 40 Ar/ 39 Ar ages of 4,219 ± 35 and 4,149 ± 41 My and when combined with thermal and diffusion models; these results constrain the formation age of the rubble pile structure to ≥4.2 billion years ago. Such a long survival time for an asteroid is attributed to the shock-absorbent nature of rubble pile material and suggests that rubble piles are hard to destroy once they are created. Our results suggest that rubble piles are probably more abundant in the asteroid belt than previously thought and provide constrain to help develop mitigation strategies to prevent asteroid collisions with Earth.

Asteroid 4 Vesta is the only largely preserved differentiated asteroid and thus is an excellent proxy to study early magmatism occurring on planets and moons. In this study, we focus on eucrite Pecora Escarpment (PCA) 82502, a medium‐ to fine‐grained eucrite which chemical analyses suggest belongs to the main howardite–eucrite–diogenite clan, albeit with some peculiarities. We carried out backscattered electron and electron backscattered diffraction microscopy analyses of the meteorite along with step‐heating 40 Ar/ 39 Ar dating analyses of various types of groundmass aliquots. We show that Pecora Escarpment 82502 is composed of medium‐grained igneous crystalline clasts and smaller fractured satellite clasts surrounded by approximately 50 µm wide impact melt veins of the same composition. Our results show that the large crystalline clasts and fine‐grained veins both display little evidence of shock processes. Six groundmass aliquots from large crystalline clasts returned concordant plateau (>70% of 39 Ar) or mini‐plateau (50–70% of 39 Ar) 40 Ar/ 39 Ar ages with a weighted mean of 4531 ± 6 Ma ( P = 0.67). Thermodynamic cooling and 40 Ar diffusion models suggest that the K/Ar system recorded and preserved the igneous age despite subsequent infiltration of hot and quickly quenched melt veins. Our new igneous age, combined with evidence for four other young volcanic and plutonic eucrites of similar age, shows that Vesta was still magmatically active around 4531 Ma. The lack of younger ages suggests that this age might well represent the end of the magmatic activity in the upper crust of Vesta. When combined with existing paleomagnetic constraints, our data suggest that 4 Vesta had an active dynamo that was still active ~35 Ma after accretion.

Electrospinning technology is widely used for the generation of nano- or micro-sized fibers, which are capable of producing highly porous materials with high surface-to-volume ratios leading to various applications in algal bioprocesses. While the applications are mainly focused on cultivation and harvesting of algal cells on confined solid spaces, simultaneous processing of immobilized biomass during wastewater treatment has shown great potential in the removal of nitrate, heavy metals, and reactive dyes. Successful fabrication of electrospun materials directly from algal biomass and/or extracts is also possible and holds high promise for improving the sustainability of algal biotechnology. This chapter includes a general introduction of algae-associated electrospun composite materials, a detailed review of their applications in (i) cellular growth and biomass harvesting, (ii) integrated wastewater treatment processes, (iii) fabrication of electrospun fibers from whole algal biomass or algae extracts, and a final conclusion with suggestions regarding future directions of this research field.

Eucrites are extraterrestrial basalts and cumulate gabbros formed, and subsequently more or less metamorphosed, at the crustal level of the HED (Howardite-Eucrite-Diogenite) parent body, thought to be the asteroid 4 Vesta. Unbrecciated eucrites offer the best way to understand the igneous, metamorphic and cooling processes occurring in the crust of Vesta following accretion since they were not substantially affected/altered by secondary impact processes. The 40Ar/39Ar system of unbrecciated eucrites should be in a relatively pristine state, and thus can inform us on the early volcanic and thermal history of the HED parent body, and, in particular, the cooling history of various crustal parts below the similar to 300 degrees C isotherm, which represents the average closure temperature of the Ar diffusion in plagioclase. We analysed plagioclase and pyroxene (+/- groundmass) separates of two cumulate (Moore County and Moama), and five (Caldera, BTN 00300, EET 90020, GRA 98098, QUE 97053) equilibrated basaltic eucrites with the 40Ar/39Ar technique using a Thermo(C) ARGUS VI multi-collection mass spectrometer. The two cumulate unequilibrated gabbros also gave cooling ages of 4531 +/- 11 Ma and 4533 +/- 12 Ma and combined with a fast cooling rate estimated from lamella thicknesses, suggest that magmatic activity persisted up to 4533 +/- 11 and 4535 +/- 12 Ma and that the plutons were intruded in a relatively shallow part of the crust, above the metamorphosed regions. Four equilibrated eucrites yielded a well-defined cluster of ages between 4523 +/- 8 Ma to 4514 +/- 6 Ma. Those ages indicate when the part of the upper crust, where those eucrites probably resided (similar to 10-15 km deep), cooled below similar to 300 degrees C at a rate of 17.3 +/- 3.6 degrees C/Ma (2r). Such a slow cooling rate combined with available global thermal models, supports the hypothesis of a global crustal metamorphism by burial and reheating of lava flows. Finally, an age of 4531 +/- 5 Ma was obtained for metamorphosed eucrite EET 90020 and, combined with petrographic observations, indicates the age of a major crustal excavation event by impact. 40Ar diffusion models suggest that it is possible to differentiate impact vs crustal cooling provided that a sufficient quantity of pyroxene is measured by 40Ar/39Ar. (C) 2020 Elsevier Ltd. All rights reserved. Eucrites are extraterrestrial basalts and cumulate gabbros formed, and subsequently more or less metamorphosed, at the crustal level of the HED (Howardite-Eucrite-Diogenite) parent body, thought to be the asteroid 4 Vesta. Unbrecciated eucrites offer the best way to understand the igneous, metamorphic and cooling processes occurring in the crust of Vesta following accretion since they were not substantially affected/altered by secondary impact processes. The 40Ar/39Ar system of unbrecciated eucrites should be in a relatively pristine state, and thus can inform us on the early volcanic and thermal history of the HED parent body, and, in particular, the cooling history of various crustal parts below the similar to 300 degrees C isotherm, which represents the average closure temperature of the Ar diffusion in plagioclase. We analysed plagioclase and pyroxene (+/- groundmass) separates of two cumulate (Moore County and Moama), and five (Caldera, BTN 00300, EET 90020, GRA 98098, QUE 97053) equilibrated basaltic eucrites with the 40Ar/39Ar technique using a Thermo(C) ARGUS VI multi-collection mass spectrometer. The two cumulate unequilibrated gabbros also gave cooling ages of 4531 +/- 11 Ma and 4533 +/- 12 Ma and combined with a fast cooling rate estimated from lamella thicknesses, suggest that magmatic activity persisted up to 4533 +/- 11 and 4535 +/- 12 Ma and that the plutons were intruded in a relatively shallow part of the crust, above the metamorphosed regions. Four equilibrated eucrites yielded a well-defined cluster of ages between 4523 +/- 8 Ma to 4514 +/- 6 Ma. Those ages indicate when the part of the upper crust, where those eucrites probably resided (similar to 10-15 km deep), cooled below similar to 300 degrees C at a rate of 17.3 +/- 3.6 degrees C/Ma (2r). Such a slow cooling rate combined with available global thermal models, supports the hypothesis of a global crustal metamorphism by burial and reheating of lava flows. Finally, an age of 4531 +/- 5 Ma was obtained for metamorphosed eucrite EET 90020 and, combined with petrographic observations, indicates the age of a major crustal excavation event by impact. 40Ar diffusion models suggest that it is possible to differentiate impact vs crustal cooling provided that a sufficient quantity of pyroxene is measured by 40Ar/39Ar. (C) 2020 Elsevier Ltd. All rights reserved.

Here, we present results of the first 40Ar/39Ar dating of osumilite, a high‐T mineral that occurs in some volcanic and high‐grade metamorphic rocks. The metamorphic osumilite studied here is from a metapelitic rock within the Rogaland–Vest Agder Sector, Norway, an area that experienced regional granulite facies metamorphism and subsequent contact metamorphism between 1,100 Ma and 850 Ma. The large grain size (~1 cm) of osumilite in the studied rock, which preserves a nominally anhydrous assemblage, increases the potential for large portions of individual grains to have remained essentially unaffected by the effects of diffusive argon loss, potentially preserving prograde ages. Step‐heating diffusion experiments yielded a maximum activation energy of ~461 kJ/mol and a pre‐exponential factor of ~8.34 × 108 cm2/s for Ar diffusion in osumilite. These parameters correspond to a relatively high closure temperature of ~620°C for a cooling rate of 10°C/Ma in an osumilite crystal with a 175 µm radius. Fragments of osumilite separated from the sample preserve a range of ages between c. 1,070 and 860 Ma. The oldest ages are inferred to date the growth of coarse‐grained osumilite during prograde granulite facies regional metamorphism, which pre‐date contact metamorphism that has historically been ascribed to the growth of osumilite in the region. The majority of fragments record ages between c. 920 and 860 Ma, inferred to reflect the growth of osumilite and/or diffusive argon loss during contact metamorphism. The retention of old 40Ar/39Ar dates was facilitated by the low diffusivity of Ar in osumilite (i.e. a closed system), large grain sizes, and anhydrous metamorphic conditions. The ability to date osumilite with the 40Ar/39Ar method provides a valuable new thermochronometer that may constrain the timing and duration of high‐T magmatic and metamorphic events.

The Australasian tektites are quench melt glass ejecta particles distributed over the Asian, Australian, and Antarctic regions, the source crater of which is currently elusive. New 40 Ar/ 39 Ar age data from four tektites: one each from Thailand, China, Vietnam, and Australia measured using three different instruments from two different laboratories and combined with published 40 Ar/ 39 Ar data yield a weighted mean age of 788.1 ± 2.8 ka (±3.0 ka, including all sources of uncertainties) (P = 0.54). This age is five times more precise compared to previous results thanks, in part, to the multicollection capabilities of the ARGUS VI noble gas mass spectrometer, which allows an improvement of almost fourfold on a single plateau age measurement. Diffusion experiments on tektites combined with synthetic age spectra and Monte Carlo diffusion models suggest that the minimum temperature of formation of the Thai tektite is between 2350 °C and 3950 °C, hence a strict minimum value of 2350 °C.

In this study, the impacts of banana peels pre-treatment stage on photofermentative hydrogen production of Rhodobacter sphaeroides 158 DSM using brewery wastewater (BWW) were investigated in a batch bioreactor. The experimental results indicate that banana peels pre-treatments can significantly enhance the cumulative hydrogen production. The maximum hydrogen production yield (408.33 mL H-2 L-wastewater(-1)) was achieved from the substrate, which was composed of 50% BWW pretreated with 1 g L-1 of banana peels for 2 h and 50% standard medium. This highest amount of hydrogen production was 2.7-folds higher than those that applied the same percentage of raw BWW as the substrate source. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

The thermal/impact histories of sixteen eucrite meteorites were investigated: three monomict eucrites (NWA 999, A-87272,87, and Stannern), five polymict eucrites (NWA 1000, NWA 1666, NWA 5601, Y-980066,100, and Y-980255,100), three quench-textured, eucrite melt rocks (Y-981646,21, Y-981651,105, and MIL 0766214), one eucrite dominantly comprised of quench-textured clasts (QUE 99005,11), three unclassified eucrite breccias (LAP 031316,9, LAR 06870,5, QUE 99799,4) and one unbrecciated eucrite (EET 92004,17), included here due to its shock features. We have measured fifteen high-precision new 40Ar/39Ar plateau ages on plagioclase and matrix for ten of these meteorites with a tight cluster of nine ages obtained from three different polymict breccias. These ages range from 4534 +/- 56 Ma to 4491 +/- 16 Ma resulting in a concordant age population (P = 0.16). The fact that such a cluster of ages is recorded in unrelated breccias which are made of a priori unrelated components, leads us to propose that those ages recorded a single heating event on a large scale, and is interpreted here as a high-energy impact event, early in the history of Vesta at 4500 +/- 4 Ma. We propose that the debris was ejected and isolated from subsequent large impacts in a secondary rubble pile asteroid where the energy of the outgoing shock wave from an impact is significantly reduced as it compacts the target material (Holsapple et al., 2002, and references therein). The other analyses define a spread of five plateau ages ranging from 3851 +/- 21 Ma to 3469 +/- 35 Ma, over similar to 380 Ma. An additional apparent plateau age of 4288 +/- 38 Ma, but with a diffusion profile of cumulative 39Ar release, along with published U-Pb apatite age of similar to 4.14 Ga, suggests that the data might either define a true continuum (normal background bombardment) from 4.5 Ga to 3.47 Ga or cluster between similar to 3.85 Ga and similar to 3.47 Ga (excavation of a fresh surface at 3.85 Ga continuously bombarded until 3.47 Ga). Both scenarios are compatible with a final ejection age of 3.47 Ga when a major impact liberates the bulk of the brecciated meteorites into another secondary rubble pile asteroid, where the brecciated eucrites stayed relatively well protected from subsequent major impacts. Based on these results and recent crater counting measurements, we propose that the excavation and bulk ejection were caused by the Rheasilvia (ca. 3.47 Ga) basin-forming impact. Diffusion models on plagioclase crystals with different Ar age spectrum signatures, from a single breccia (NWA1666; 4501 +/- 7 Ma), suggest that either: (1) the formation of the breccia is very young, or (2) different plagioclase crystals have different diffusion characteristics, and/or (3) the porosity caused heterogeneous temperatures during an impact heating event, particularly likely if the 4.5 Ga brecciated eucrites were stored in a rubble pile asteroid. Many or possibly most large asteroids being re-accumulated rubble piles with potential large porosity (Holsapple et al., 2002). Scenarios (2) and (3) preclude the usage of multi-grain aliquots to decipher the time-temperature history of most impact breccia using 40Ar/39Ar thermochronology. (C) 2019 Elsevier Ltd. All rights reserved. The thermal/impact histories of sixteen eucrite meteorites were investigated: three monomict eucrites (NWA 999, A-87272,87, and Stannern), five polymict eucrites (NWA 1000, NWA 1666, NWA 5601, Y-980066,100, and Y-980255,100), three quench-textured, eucrite melt rocks (Y-981646,21, Y-981651,105, and MIL 0766214), one eucrite dominantly comprised of quench-textured clasts (QUE 99005,11), three unclassified eucrite breccias (LAP 031316,9, LAR 06870,5, QUE 99799,4) and one unbrecciated eucrite (EET 92004,17), included here due to its shock features. We have measured fifteen high-precision new 40Ar/39Ar plateau ages on plagioclase and matrix for ten of these meteorites with a tight cluster of nine ages obtained from three different polymict breccias. These ages range from 4534 +/- 56 Ma to 4491 +/- 16 Ma resulting in a concordant age population (P = 0.16). The fact that such a cluster of ages is recorded in unrelated breccias which are made of a priori unrelated components, leads us to propose that those ages recorded a single heating event on a large scale, and is interpreted here as a high-energy impact event, early in the history of Vesta at 4500 +/- 4 Ma. We propose that the debris was ejected and isolated from subsequent large impacts in a secondary rubble pile asteroid where the energy of the outgoing shock wave from an impact is significantly reduced as it compacts the target material (Holsapple et al., 2002, and references therein). The other analyses define a spread of five plateau ages ranging from 3851 +/- 21 Ma to 3469 +/- 35 Ma, over similar to 380 Ma. An additional apparent plateau age of 4288 +/- 38 Ma, but with a diffusion profile of cumulative 39Ar release, along with published U-Pb apatite age of similar to 4.14 Ga, suggests that the data might either define a true continuum (normal background bombardment) from 4.5 Ga to 3.47 Ga or cluster between similar to 3.85 Ga and similar to 3.47 Ga (excavation of a fresh surface at 3.85 Ga continuously bombarded until 3.47 Ga). Both scenarios are compatible with a final ejection age of 3.47 Ga when a major impact liberates the bulk of the brecciated meteorites into another secondary rubble pile asteroid, where the brecciated eucrites stayed relatively well protected from subsequent major impacts. Based on these results and recent crater counting measurements, we propose that the excavation and bulk ejection were caused by the Rheasilvia (ca. 3.47 Ga) basin-forming impact. Diffusion models on plagioclase crystals with different Ar age spectrum signatures, from a single breccia (NWA1666; 4501 +/- 7 Ma), suggest that either: (1) the formation of the breccia is very young, or (2) different plagioclase crystals have different diffusion characteristics, and/or (3) the porosity caused heterogeneous temperatures during an impact heating event, particularly likely if the 4.5 Ga brecciated eucrites were stored in a rubble pile asteroid. Many or possibly most large asteroids being re-accumulated rubble piles with potential large porosity (Holsapple et al., 2002). Scenarios (2) and (3) preclude the usage of multi-grain aliquots to decipher the time-temperature history of most impact breccia using 40Ar/39Ar thermochronology. (C) 2019 Elsevier Ltd. All rights reserved. The thermal/impact histories of sixteen eucrite meteorites were investigated: three monomict eucrites (NWA 999, A-87272,87, and Stannern), five polymict eucrites (NWA 1000, NWA 1666, NWA 5601, Y-980066,100, and Y-980255,100), three quench-textured, eucrite melt rocks (Y-981646,21, Y-981651,105, and MIL 0766214), one eucrite dominantly comprised of quench-textured clasts (QUE 99005,11), three unclassified eucrite breccias (LAP 031316,9, LAR 06870,5, QUE 99799,4) and one unbrecciated eucrite (EET 92004,17), included here due to its shock features. We have measured fifteen high-precision new 40Ar/39Ar plateau ages on plagioclase and matrix for ten of these meteorites with a tight cluster of nine ages obtained from three different polymict breccias. These ages range from 4534 +/- 56 Ma to 4491 +/- 16 Ma resulting in a concordant age population (P = 0.16). The fact that such a cluster of ages is recorded in unrelated breccias which are made of a priori unrelated components, leads us to propose that those ages recorded a single heating event on a large scale, and is interpreted here as a high-energy impact event, early in the history of Vesta at 4500 +/- 4 Ma. We propose that the debris was ejected and isolated from subsequent large impacts in a secondary rubble pile asteroid where the energy of the outgoing shock wave from an impact is significantly reduced as it compacts the target material (Holsapple et al., 2002, and references therein). The other analyses define a spread of five plateau ages ranging from 3851 +/- 21 Ma to 3469 +/- 35 Ma, over similar to 380 Ma. An additional apparent plateau age of 4288 +/- 38 Ma, but with a diffusion profile of cumulative 39Ar release, along with published U-Pb apatite age of similar to 4.14 Ga, suggests that the data might either define a true continuum (normal background bombardment) from 4.5 Ga to 3.47 Ga or cluster between similar to 3.85 Ga and similar to 3.47 Ga (excavation of a fresh surface at 3.85 Ga continuously bombarded until 3.47 Ga). Both scenarios are compatible with a final ejection age of 3.47 Ga when a major impact liberates the bulk of the brecciated meteorites into another secondary rubble pile asteroid, where the brecciated eucrites stayed relatively well protected from subsequent major impacts. Based on these results and recent crater counting measurements, we propose that the excavation and bulk ejection were caused by the Rheasilvia (ca. 3.47 Ga) basin-forming impact. Diffusion models on plagioclase crystals with different Ar age spectrum signatures, from a single breccia (NWA1666; 4501 +/- 7 Ma), suggest that either: (1) the formation of the breccia is very young, or (2) different plagioclase crystals have different diffusion characteristics, and/or (3) the porosity caused heterogeneous temperatures during an impact heating event, particularly likely if the 4.5 Ga brecciated eucrites were stored in a rubble pile asteroid. Many or possibly most large asteroids being re-accumulated rubble piles with potential large porosity (Holsapple et al., 2002). Scenarios (2) and (3) preclude the usage of multi-grain aliquots to decipher the time-temperature history of most impact breccia using 40Ar/39Ar thermochronology. (C) 2019 Elsevier Ltd. All rights reserved.

The Australasian tektites are quench melt glass ejecta particles distributed over the Asian, Australian, and Antarctic regions, the source crater of which is currently elusive. New Ar-40/Ar-39 age data from four tektites: one each from Thailand, China, Vietnam, and Australia measured using three different instruments from two different laboratories and combined with published Ar-40/Ar-39 data yield a weighted mean age of 788.1 +/- 2.8 ka (+/- 3.0 ka, including all sources of uncertainties) (P = 0.54). This age is five times more precise compared to previous results thanks, in part, to the multicollection capabilities of the ARGUS VI noble gas mass spectrometer, which allows an improvement of almost fourfold on a single plateau age measurement. Diffusion experiments on tektites combined with synthetic age spectra and Monte Carlo diffusion models suggest that the minimum temperature of formation of the Thai tektite is between 2350 degrees C and 3950 degrees C, hence a strict minimum value of 2350 degrees C.

Hexagonal boron nitride (h-BN) is rendered magnetically responsive in aqueous media by binding superparamagnetic magnetite nanoparticles 8.5-18.5 nm in diameter on the surface. The composite material was generated under continuous flow in water in a dynamic thin film in a vortex fluidic device (VFD) with the source of iron generated by laser ablation of a pure iron metal target in the air above the liquid using a Nd:YAG pulsed laser operating at 1064 nm and 360 mJ. Optimum operating parameters of the VFD were a rotational speed of 7.5k rpm for the 20 mm OD (17.5 mm ID) borosilicate glass tube inclined at 45 degrees, with a h-BN concentration at 0.1 mg mL(-1), delivered at 1.0 mL min(-1) using a magnetically stirred syringe to keep the h-BN uniformly dispersed in water prior to injection into the base of the rapidly rotating tube. The resulting composite material, containing 5.75% weight of iron, exhibited high phosphate ion adsorption capacity, up to 171.2 mg PO43- per gram Fe, which was preserved on recycling the material five times.

BACKGROUND: Algal growth on solid surfaces confers the advantage of combining the algal harvesting and bioprocessing steps at a single stage, in addition to the easier handling of the immobilized cells that occupy reduced amount of space. The current work employed the application of macroporous poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel disks as a water-insoluble, non-toxic and recyclable immobilization matrix for different microalgal strains (Nannochloropsis sp., Dunaliella salina, and Botryococcus braunii) that offer valueadded products for various commercial applications. This article is protected by copyright. All rights reserved. This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/jctb.5642 A cc ep te d A rti cl e RESULTS: The study demonstrated the effect of variations in the surface characteristics of the algal strains and hydrogel surfaces on the immobilization efficiencies. Gelatin was further used to modify PHEMA hydrogels for achieving higher bioaffinity and surface hydrophilicity. The results showed that highly salt-tolerant microalgal cells (Dunaliella salina, Nannochloropsis sp.) had significantly higher tendencies to attach on the gelatin-modified PHEMA hydrogel compare to the freshwater B. braunii colonies; embedded within an extracellular matrix mainly made of hydrophobic components; which displayed better attachment to the unmodified PHEMA hydrogels. CONCLUSION: The proposed PHEMA hydrogels are easily-manufactured and highly durable materials with the hydrogel disks still retaining their integrity after several years when in contact with a liquid. PHEMA disks also own the benefits of having adjustable porosities by changing the composition of the polymerization mixture, and modifiable surface properties by simply binding various synthetic or natural molecules on their surfaces, which can bring several new opportunities for harvesting of various microalgal cells with different surface morphologies and chemical compositions.

BACKGROUNDAlgal growth on solid surfaces confers the advantage of combining the algal harvesting and bioprocessing steps at a single stage, in addition to the easier handling of the immobilized cells that occupy a reduced amount of space. The current work employed the application of macroporous poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel disks as a water-insoluble, non-toxic and recyclable immobilization matrix for different microalgal strains (Nannochloropsis sp., Dunaliella salina, and Botryococcus braunii) that offer value-added products for various commercial applications. RESULTSThe study demonstrated the effect of variations in the surface characteristics of the algal strains and hydrogel surfaces on the immobilization efficiencies. Gelatin was further used to modify PHEMA hydrogels to achieve higher bioaffinity and surface hydrophilicity. The results showed that highly salt-tolerant microalgal cells (Dunaliella salina, Nannochloropsis sp.) had significantly higher tendencies to attach on the gelatin-modified PHEMA hydrogel compared with the freshwater B. braunii colonies; embedded within an extracellular matrix mainly made of hydrophobic components, which displayed better attachment to the unmodified PHEMA hydrogels. CONCLUSIONThe proposed PHEMA hydrogels are easily-manufactured and highly durable materials with the hydrogel disks still retaining their integrity after several years when in contact with a liquid. PHEMA disks also have the benefits of having adjustable porosities by changing the composition of the polymerization mixture, and modifiable surface properties by simply binding various synthetic or natural molecules on their surfaces, which can bring several new opportunities for harvesting various microalgal cells with different surface morphologies and chemical compositions. (c) 2018 Society of Chemical Industry

The synergistic effects and optimization of pH, carbon-to-nitrogen ratio (C/N), and light intensity (I) on the photo-fermentative hydrogen production of Rhodobacter sphaeroides 158 DSM and light conversion efficiency have been investigated under different conditions of pH (6.5-8); C/N (15-35); and light intensity (35-185 W m(-2)). Response surface methodology (RSM) and Box-Behnken experimental design (BBD) were used to identify the optimum values of the three key parameters of pH, C/N, and I, based on the impact on hydrogen production potential (HPP), hydrogen production rate (HPR), and light conversion efficiency eta. With desirability value of 0.91, the optimum values of 7.4, 27.5, and 126 W m(-2) were identified for pH, C/N, and I respectively, with HPP, HPR and eta reaching 960 mL L-1, 41.74 mL L-1 h(-1), and 0.31 respectively. Regression analysis indicated a good fit between experimental and model data. The study showed that both C/N ratio and I have crucial and significant effect on the HPP, HPR and eta, followed by pH, the synergistic effect of pH-I and C/N-I on the light conversion efficiency (eta) was significant while pH -C/N was insignificant. The results and analysis obtained could be very useful for better optimizing the photo-fermentative hydrogen production. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Highly faceted superparamagnetic magnetite nanoparticles roughly 11 nm in diameter are readily accessible in the presence of p-phosphonated calix[n]arenes of different ring sizes (n=4, 5 and 6), through the use of a simple co-precipitation technique. In contrast, the larger calix[8]arene affords spherical particles of comparable size. The maximum magnetization is 70-60 emu g-1 , which decreases with increasing size of the calixarene macrocycle, and the evidence indicates that the calixarenes bind to the surface of the nanoparticles via the phosphonate head groups rather than the phenolic oxygen centers. The stabilized nanoparticles show dual functionality: they remove up to 62 % of nitrate nitrogen and 48 % of phosphate from an aqueous effluent after 24 hours at concentrations of only 1 g L-1 of calixarene-coated nanoparticles.

In situ extraterrestrial samples returned for study (e.g., from the Moon) are crucial in understanding the origin and evolution of the Solar System as, contrary to meteorites, they provide a known geological context for the samples and their analyses. Asteroid 25143 Itokawa is a rubble-pile asteroid consisting of reaccumulated fragments from a catastrophically disrupted monolithic parent asteroid, and from which regolith dust particles have been recovered by the Hayabusa space probe (Japan Aerospace Exploration Agency). We analyzed two dust particles using electron backscatter diffraction and Ar-40/Ar-39 dating techniques. One of the grains, showing signs of 15-25 GPa impact shock pressure, yielded a Ar-40/Ar-39 plateau age of 2.3 +/- 0.1 Ga. We developed a novel temperature-pressure-porosity model, coupled with diffusion models to show that the relatively low pressure and high temperature i Lnvolved in the impact process can be reconciled only if the asteroid was already made of porous material at ca. 2.3 Ga and, thus, if asteroid Itokawa was already formed, thereby providing a minimum age for catastrophic asteroid breakup. A second particle shows no sign of deformation, indicating shock pressure of <10 GPa and a calculated maximum temperature of similar to 200 degrees C. This low temperature estimate is compatible with a lack of isotopic resetting for this particle. This suggests that the breakup of Itokawa's parent was a relatively low-temperature process at the scale of the asteroid, and occurred on a pre-shattered parent body.

No meteorites from Mercury and Venus have been conclusively identified so far. In this study, we develop an original approach based on extensive Monte Carlo simulations and diffusion models to explore the radiogenic argon (Ar-40*) and helium (He-4*) loss behavior and the range of Ar-40/Ar-39 and (U-Th)/He age signatures expected for a range of crystals if meteorites from these planets were ever to be found. We show that we can accurately date the crystallization age of a meteorite from both Mercury and Venus using the Ar-40/Ar-39 technique on clinopyroxene (+/- orthopyroxene) and that its Ar-40/Ar-39 age should match the Pb-Pb age. At the surface of Mercury, phases like albite and anorthite will exhibit a complete range of Ar-40* loss ranging from 0% to 100%, whereas merrillite and apatite will show 100% He-4* loss. By measuring the crystal size and diffusion parameters of a series of plagioclase crystals, one can inverse the Ar-40* loss value to estimate the maximum temperature experienced by a rock, and narrow down the possible pre-ejection location of the meteorite at the surface of Mercury. At the surface of Venus, plagioclase and phosphate phases will only record the age of ejection. The (U-Th)/He systematics of merrillite and apatite will be, respectively, moderately and strongly affected by He-4* loss during the transit of the meteorite from its host planet to Earth. Finally, meteorites from Mercury or Venus will each have their own Ar-40/Ar-39 and (U-Th)/He isotopic age and Ar-38(c) cosmic ray exposure age signatures over a series of different crystal types, allowing to unambiguously recognize a meteorite for any of these two planets using radiogenic and cosmogenic noble gases.

Algal cultivation has tremendous potential in wastewater treatment, and its simultaneous biomass production has advantages for the production of value added products such as biodiesel, fertilizers and pharmaceuticals. Some obstacles to obtaining a productive biological water treatment and bioenergy system are the harvesting and processing of biomass. Such issues can be addressed using nano-bio hybridization approaches by simplifying the microbial harvesting step along with increasing the efficiency of wastewater treatment. This review highlights studies within our research group that are based on the fabrication of functional hybrid materials using algal biomass, including: (i) electrospun nanofibers; (ii) laminar nanomaterials; and (iii) magnetic nanoparticles impregnated in a polymer. All of these techniques have been used for the removal of waste pollutants such as nitrate and phosphate ions. The multidisciplinary techniques have potential to provide effective algal culture systems for industrial applications, while having a significant impact on wastewater treatment. (c) 2017 Society of Chemical Industry