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  • Additives
  • ddc:550.724
  • perovskiteferroelectricpowder neutron diffraction
  • Springer Berlin Heidelberg  (16)
  • Lagos (Nigeria)  (3)
  • American Chemical Society  (2)
  • International Union of Crystallography (IUCr)  (2)
  • 1
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24159 | 19325 | 2018-05-13 13:04:38 | 24159 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: Completely randomized design with duplicate groups were used to study the growth performance of 400 fingerlings of Clarias gariepinus in 2m x 2m x 1m concrete tanks in an out-door hatchery complex of National Institute for Freshwater Fisheries Research (NIFFR), New Bussa, Niger State, Nigeria. Graded levels (0, 1,2,3 or 4) % of yeast (Saccharomyces cerevisiae) was included into a 40% crude protein (C.P) NIFFR floating basal diet and fed to Clarias gariepinus in tanks for 16 weeks and 35% in the last 4 weeks. This was to determine the optimum level of supplemental yeast inclusion as a floater additive into diets of C. gariepinus and to quantify feed and its cost for raising a kilogram of the fish fed diets. The experiment was geared towards development of cost effective standard floating feed for Clarias gariepinus. There was no significant difference in weight gain (WG), feed consumed (FC), specific growth rate (SGR), survival, cost of feed consumed (CFC) and palatability test of flesh (P〉0.05) except FCR (P〈0.05) and feed cost per kilogram of fish (P〈0.05) at the end of 8 and 20 weeks. There was no histopathological defect observed on the fish and fish carcass. It was concluded that 2% or 1 % level of yeast can be included in NIFFR floating feed with the assurance of producing a kilogram of C. gariepinus with a feed of N300.00 under good management practices based on ingredient ruling price at the time of this study and this might be capable of increasing farmer's income in fish production.
    Description: Includes: 1 table and 2 figures.;Also includes: 21 references.
    Keywords: Aquaculture ; Ecology ; Clarias gariepinus ; Nigeria ; Niger ; Yeast ; Floating additives ; Performance ; Clarias gariepinus ; freshwater environment ; Growth rate ; Freshwater fish ; Fingerlings ; Artificial feeding ; Feeding experiments ; Feed ; Yeasts ; Additives ; Culture tanks ; Cost analysis ; Performance assessment ; Fish culture
    Repository Name: AquaDocs
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  • 2
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24166 | 19325 | 2018-05-13 18:40:22 | 24166 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: Probiotics are a promising feed additive to stimulate animal growth and secure a low disease response in aquaculture industry where there are high stocking densities in shrimp and fish production. Fermented locust beans (Parkia biglobosa) are known to be rich in protein and used as food condiment. Probiotic bacteria were isolated from this locally available food material. Culture and characterizations of isolates were carried out. Sugar fermentation patterns were determined by using an API 50 CHL system and incubation were performed anaerobically at 37~'C. MRS broth culture grown at 37~'C overnight was added to 9ml of MRS Agar and the bacteria were incubated at 37~'C for 24 and 48 hrs. Discrete and single colony of lactobacillus was isolated using colony morphology and biochemical tests. The most significant viable taxa isolated was Lactobacillus fermentum at a pH range of (3.0-8.0), while the least viable taxa isolated was Leuconostoc mesenteroides ssp. Microscopically they were Grampositive, rod shaped, non- motile, catalase negative and absence of Endospore.
    Description: Includes: 2 tables and 2 plates.;Also includes: 15 references.
    Keywords: Aquaculture ; Nigeria ; Lagos ; Locust bean ; Probiotics ; Lactobacillus ; Probiotics ; freshwater environment ; Feed ; Additives ; Aquaculture ; Microorganisms ; Bacteria ; Disease resistance ; Fermented products ; Fish culture ; Shrimp culture
    Repository Name: AquaDocs
    Type: conference_item , TRUE
    Format: application/pdf
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    Format: 60-63
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  • 3
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    FISON | Lagos (Nigeria)
    In:  http://aquaticcommons.org/id/eprint/24174 | 19325 | 2018-05-13 18:56:53 | 24174 | Fisheries Society of Nigeria
    Publication Date: 2021-07-15
    Description: The present study examined the utilization potential of date palm seed (DPS) as feed additive in the diet of African catfish Clarias gariepinus for efficient feed utilization. A total of 150 African catfish (weight ranged from 81.13 to 91.35 g) were divided into five experimental groups. The experiment was conducted for 70 days. Experimental diets were identical in all composition except for the variation in DPS level. Non-inclusion of DPS was used at 0% (control) and other levels are 0.5% (diet 2), 1.0% (diet 3), 1.5% (diet 4) and 2.0% (diet 5). The growth performance and nutrient utilization of African catfish including Weight Gain (WG), Specific Growth Rate (SGR), Protein Efficiency Ratio (PER) and Protein Productive Value (PPV) were significantly (p〈0.05) higher than those of fish fed control diets, where DPS supplementation at 1.5% appears to be generally higher than other levels. In the same trend fish fed diets with DPS supplementation produced improved fish carcass values and the haematology of fish was generally better from diets in all DPS fed fish. Overall production performance and subsequent fish quality assessments indicated that the diets containing 1.5% DPS level recorded the best performance in African catfish compared to other levels including the control diet. Based on the result of the present study, it is concluded that date palm seed supplementation positively influenced growth performance and feed utilization of African catfish as well as ensuring their healthy status.
    Description: Includes: 3 tables.;Also includes: 20 references.
    Keywords: Aquaculture ; Ecology ; Clarias gariepinus ; freshwater environment ; Feed ; Additives ; Utilization ; Freshwater fish ; Juveniles ; Diets ; Feeding experiments ; Fish culture ; Feed efficiency
    Repository Name: AquaDocs
    Type: conference_item , TRUE
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  • 4
    Publication Date: 2022-10-26
    Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Walsh, A. N., Reddy, C. M., Niles, S. F., McKenna, A. M., Hansel, C. M., & Ward, C. P. Plastic formulation is an emerging control of its photochemical fate in the ocean. Environmental Science & Technology, 55(18), (2021): 12383–12392, https://doi.org/10.1021/acs.est.1c02272.
    Description: Sunlight exposure is a control of long-term plastic fate in the environment that converts plastic into oxygenated products spanning the polymer, dissolved, and gas phases. However, our understanding of how plastic formulation influences the amount and composition of these photoproducts remains incomplete. Here, we characterized the initial formulations and resulting dissolved photoproducts of four single-use consumer polyethylene (PE) bags from major retailers and one pure PE film. Consumer PE bags contained 15–36% inorganic additives, primarily calcium carbonate (13–34%) and titanium dioxide (TiO2; 1–2%). Sunlight exposure consistently increased production of dissolved organic carbon (DOC) relative to leaching in the dark (3- to 80-fold). All consumer PE bags produced more DOC during sunlight exposure than the pure PE (1.2- to 2.0-fold). The DOC leached after sunlight exposure increasingly reflected the 13C and 14C isotopic composition of the plastic. Ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry revealed that sunlight exposure substantially increased the number of DOC formulas detected (1.1- to 50-fold). TiO2-containing bags photochemically degraded into the most compositionally similar DOC, with 68–94% of photoproduced formulas in common with at least one other TiO2-containing bag. Conversely, only 28% of photoproduced formulas from the pure PE were detected in photoproduced DOC from the consumer PE. Overall, these findings suggest that plastic formulation, especially TiO2, plays a determining role in the amount and composition of DOC generated by sunlight. Consequently, studies on pure, unweathered polymers may not accurately represent the fates and impacts of the plastics entering the ocean.
    Description: Funding was provided by the Seaver Institute, the Gerstner Family Foundation, Woods Hole Oceanographic Institution, and the National Science Foundation Graduate Research Fellowship Program (A.N.W.). The Ion Cyclotron Resonance user facility at the National High Magnetic Field Laboratory is supported by the National Science Foundation Division of Chemistry and Division of Materials Research through DMR-1644779 and the State of Florida.
    Keywords: Plastic pollution ; Marine debris ; Additives ; Dissolved organic carbon ; Photochemical oxidation ; FT-ICR-MS ; Titanium dioxide
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 5
    Publication Date: 2022-12-07
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in James, B., de Vos, A., Aluwihare, L., Youngs, S., Ward, C., Nelson, R., Michel, A., Hahn, M., & Reddy, C. Divergent forms of pyroplastic: lessons learned from the M/V X-Press Pearl ship fire. ACS Environmental Au, 2(5), (2022): 467–479, https://doi.org/10.1021/acsenvironau.2c00020.
    Description: In late May 2021, the M/V X-Press Pearl container ship caught fire while anchored 18 km off the coast of Colombo, Sri Lanka and spilled upward of 70 billion pieces of plastic or “nurdles” (∼1680 tons), littering the country’s coastline. Exposure to combustion, heat, chemicals, and petroleum products led to an apparent continuum of changes from no obvious effects to pieces consistent with previous reports of melted and burned plastic (pyroplastic) found on beaches. At the middle of this continuum, nurdles were discolored but appeared to retain their prefire morphology, resembling nurdles that had been weathered in the environment. We performed a detailed investigation of the physical and surface properties of discolored nurdles collected on a beach 5 days after the ship caught fire and within 24 h of their arrival onshore. The color was the most striking trait of the plastic: white for nurdles with minimal alteration from the accident, orange for nurdles containing antioxidant degradation products formed by exposure to heat, and gray for partially combusted nurdles. Our color analyses indicate that this fraction of the plastic released from the ship was not a continuum but instead diverged into distinct groups. Fire left the gray nurdles scorched, with entrained particles and pools of melted plastic, and covered in soot, representing partial pyroplastics, a new subtype of pyroplastic. Cross sections showed that the heat- and fire-induced changes were superficial, leaving the surfaces more hydrophilic but the interior relatively untouched. These results provide timely and actionable information to responders to reevaluate cleanup end points, monitor the recurrence of these spilled nurdles, gauge short- and long-term effects of the spilled nurdles to the local ecosystem, and manage the recovery of the spill. These findings underscore partially combusted plastic (pyroplastic) as a type of plastic pollution that has yet to be fully explored despite the frequency at which plastic is burned globally.
    Description: This work was supported by the Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution (WHOI), with funding provided by the Weston Howland Jr. Postdoctoral Scholarship. Additional support was provided by the WHOI Marine Microplastics Catalyst Program, the WHOI Marine Microplastics Innovation Accelerator Program, the WHOI Investment in Science Fund, the March Marine Initiative (a program of March Limited, Bermuda), The Seaver Institute, Gerstner Philanthropies, the Wallace Research Foundation, the Richard Saltonstall Charitable Foundation, the Harrison Foundation, Hollis and Ermine Lovell Charitable Foundation, and the Richard Grand Foundation. AdV was supported by funding from the Schmidt Foundation.
    Keywords: Microplastic ; Resin pellets ; Pollution ; Additives ; Open burning ; Weathering ; Maritime accident
    Repository Name: Woods Hole Open Access Server
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  • 6
    Publication Date: 2023-06-20
    Description: Aufgrund deutlich erhöhter Wärmebedarfsdichten urbaner Räume besteht in besonderem Maße hier die Möglichkeit und Erfordernis, durch eine nachhaltige Wärmeversorgung und saisonale Wärmespeicherung im geologischen Untergrund einen wesentlichen Beitrag zu den national und international gesetzten Klimaschutzzielen zu liefern. Eine effiziente Möglichkeit zur Wärmegewinnung und -speicherung bieten hierfür Erdwärmesonden, die jedoch aus Gründen des vorbeugenden Grundwasserschutzes in Bereichen der Trinkwassernutzung heutzutage meist nicht oder nur beschränkt genehmigt werden. Numerische Simulationen einer Erdwärmesondenleckage für Randbedingungen eines zur Trinkwassergewinnung genutzten norddeutschen Aquifers auf Grundlage von aufgearbeiteten stoffspezifischen Abbauratenkonstanten zeigen, dass Grenzwerte für die meisten handelsüblichen Wärmeträgerfluid-Inhaltsstoffe bereits bei einem Abstand von nur 100 m zwischen Erdwärmesonde und Trinkwasserentnahme aufgrund starker Verdünnung und mikrobiellen Abbaus mit einem Faktor 〉 10 unterschritten werden. Vor dem Hintergrund dieser Ergebnisse und angesichts der Zielsetzung einer Reduktion fossiler Primärenergiequellen um 80–95 % bis 2050, erscheinen pauschale Abstandsvorgaben (von zurzeit 〉 1000 m) daher zumindest hinsichtlich der Trinkwassergefährdung durch Erdwärmesondenleckagen diskussionswürdig.
    Description: Christian-Albrechts-Universität zu Kiel (3094)
    Keywords: ddc:549 ; Borehole heat exchanger ; Heat transfer fluids ; Additives ; Groundwater ; Risk assessment
    Language: German
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  • 7
    Publication Date: 2023-06-23
    Description: Magmas vesiculate during ascent, producing complex interconnected pore networks, which can act as outgassing pathways and then deflate or compact to volcanic plugs. Similarly, in-conduit fragmentation events during dome-forming eruptions create open systems transiently, before welding causes pore sealing. The percolation threshold is the first-order transition between closed- and open-system degassing dynamics. Here, we use time-resolved, synchrotron-source X-ray tomography to image synthetic magmas that go through cycles of opening and closing, to constrain the percolation threshold ΦC at a range of melt crystallinity, viscosity and overpressure pertinent to shallow magma ascent. During vesiculation, we observed different percolative regimes for the same initial bulk crystallinity depending on melt viscosity and gas overpressure. At high viscosity (〉 106 Pa s) and high overpressure (~ 1–4 MPa), we found that a brittle-viscous regime dominates in which brittle rupture allows system-spanning coalescence at a low percolation threshold (ΦC~0.17) via the formation of fracture-like bubble chains. Percolation was followed by outgassing and bubble collapse causing densification and isolation of the bubble network, resulting in a hysteresis in the evolution of connectivity with porosity. At low melt viscosity and overpressure, we observed a viscous regime with much higher percolation threshold (ΦC 〉 0.37) due to spherical bubble growth and lower degree of crystal connection. Finally, our results also show that sintering of crystal-free and crystal-bearing magma analogues is characterised by low percolation thresholds (ΦC = 0.04 – 0.10). We conclude that the presence of crystals lowers the percolation threshold during vesiculation and may promote outgassing in shallow, crystal-rich magma at initial stages of Vulcanian and Strombolian eruptions.
    Description: Paul Scherrer Institut http://dx.doi.org/10.13039/501100004219
    Description: European Research Council http://dx.doi.org/10.13039/501100000781
    Description: NERC
    Description: Deutsche Forschungsgemeinschaft
    Keywords: ddc:550.724 ; Effusive-explosive transition ; Percolation threshold ; Outgassing ; Crystal-rich magma ; Magma viscosity ; Gas overpressure ; Porosity ; Pore connectivity ; Hysteresis ; Strombolian/Vulcanian eruptions ; Dome-forming eruptions
    Language: English
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  • 8
    Publication Date: 2023-06-23
    Description: Magma ascent during silicic dome-forming eruptions is characterized by significant changes in magma viscosity, permeability, and gas overpressure in the conduit. These changes depend on a set of parameters such as ascent rate, outgassing and crystallization efficiency, and magma viscosity, which in turn may influence the prevailing conditions for effusive versus explosive activity. Here, we combine chemical and textural analyses of tephra with viscosity models to provide a better understanding of the effusive-explosive transitions during Vulcanian phases of the 9.4 ka eruption of Kilian Volcano, Chaîne des Puys, France. Our results suggest that effusive activity at the onset of Vulcanian episodes at Kilian Volcano was promoted by (i) rapid ascent of initially crystal-poor and volatile-rich trachytic magma, (ii) a substantial bulk and melt viscosity increase driven by extensive volatile loss and crystallization, and (iii) efficient degassing/outgassing in a crystal-rich magma at shallow depths. Trachytic magma repeatedly replenished the upper conduit, and variations in the amount of decompression and cooling caused vertical textural stratification, leading to variable degrees of crystallization and outgassing. Outgassing promoted effusive dome growth and occurred via gas percolation through large interconnected vesicles, fractures, and tuffisite veins, fostering the formation of cristobalite in the carapace and talus regions. Build-up of overpressure was likely caused by closing of pore space (bubbles and fractures) in the dome through a combination of pore collapse, cristobalite formation, sintering in tuffisite veins, and limited pre-fragmentation coalescence in the dome or underlying hot vesicular magma. Sealing of the carapace may have caused a transition from open- to closed- system degassing and to renewed explosive activity. We generalize our findings to propose that the broad spectrum of eruptive styles for trachytic magmas may be inherited from a combination of characteristics of trachytic melts that include high water solubility and diffusivity, rapid microlite growth, and low melt viscosity compared to their more evolved subalkaline dacitic and rhyolitic equivalents. We show that trachytes may erupt with a similar style (e.g., Vulcanian) but at significantly higher ascent rates than their andesitic, dacitic, and rhyolitic counterparts. This suggests that the periodicity of effusive-explosive transitions at trachytic volcanoes may differ from that observed at the well-monitored andesitic, dacitic, and rhyolitic volcanoes, which has implications for hazard assessment associated with trachytic eruptions.
    Description: ERC ADV 2018
    Keywords: ddc:550.724 ; Effusive-explosive transitions ; Trachytic magma ; Vulcanian eruption ; Magma Viscosity ; Crystallization ; Degassing ; Nanolites ; Cristobalite
    Language: English
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  • 9
    Publication Date: 2023-06-23
    Description: Subsurface magmatic–hydrothermal systems are often associated with elevated electrical conductivities in the Earthʼs crust. To facilitate the interpretation of these data and to allow distinguishing between the effects of silicate melts and fluids, the electrical conductivity of aqueous fluids in the system H 2 O–HCl was measured in an externally heated diamond anvil cell. Data were collected to 700 °C and 1 GPa, for HCl concentrations equivalent to 0.01, 0.1, and 1 mol/l at ambient conditions. The data, therefore, more than double the pressure range of previous measurements and extend them to geologically realistic HCl concentrations. The conductivities 𝜎 (in S/m) are well reproduced by a numerical model log 𝜎 = −2.032 + 205.8 T−1 + 0.895 log c + 3.888 log 𝜌 + logΛ0(T,𝜌), where T is the temperature in K, c is the HCl concentration in wt. %, and 𝜌 is the density of pure water at the corresponding pressure and temperature conditions. Λ0(T,𝜌) is the limiting molar conductivity (in S cm2 mol −1 ) at infinite dilution, Λ0(T,𝜌) = 2550.14 − 505.10𝜌 − 429,437 T−1 . A regression fit of more than 800 data points to this model yielded R2 = 0.95. Conductivities increase with pressure and fluid densities due to an enhanced dissociation of HCl. However, at constant pressures, conductivities decrease with temperature because of reduced dissociation. This effect is particularly strong at shallow crustal pressures of 100–200 MPa and can reduce conductivities by two orders of magnitude. We, therefore, suggest that the low conductivities sometimes observed at shallow depths below the volcanic centers in magmatic–hydrothermal systems may simply reflect elevated temperatures. The strong negative temperature effect on fluid conductivities may offer a possibility for the remote sensing of temperature variations in such systems and may allow distinguishing the effects of magma intrusions from changes in hydrothermal circulation. The generally very high conductivities of HCl–NaCl–H 2 O fluids at deep crustal pressures (500 MPa–1 GPa) imply that electrical conductors in the deep crust, as in the Altiplano magmatic province and elsewhere, may at least partially be due to hydrothermal activity.
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: Universität Bayreuth (3145)
    Keywords: ddc:550.724 ; Electrical conductivity ; Fluid ; HCl ; Hydrothermal systems ; Magnetotelluric data
    Language: English
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  • 10
    Publication Date: 2023-06-23
    Description: Hydrothermal eruptions are characterised by violent explosions ejecting steam, water, mud, and rock. They pose a risk to tourism and the operation of power plants in geothermal areas around the world. Large events with a severe destructive threat are often intensified by the injection of magmatic fluids along faults and fractures within volcano-tectonic rifting environments, such as the Taupo Volcanic Zone. How these hydrothermal eruptions progress, how craters form and the scale of ejecta impacts, are all influenced by the local geology and reservoir hydrology. By analysing breccia lithology, undisturbed strata proximal to the explosion sites, and conducting tailored decompression experiments, we elucidate the eruption sequence that formed Champagne Pool, Wai-o-tapu, New Zealand. This iconic touristic site was formed by a violent hydrothermal eruption at ~ 700 years B.P. Samples from undisturbed drill cores and blocks ejected in the eruption were fragmented in shock-tube experiments under the moderate pressure/temperature conditions estimated for this system (3–4 MPa, 210–220 °C). Our results show that this was a two-phase eruption. It started with an initial narrow jetting of deep-sourced lithologies, ejecting fragments from at least a 110-m depth. This event was overtaken by a larger, broader, and dominantly shallower eruption driven by decompression of much more geothermal fluid within a soft and porous ignimbrite horizon. The second phase was triggered once the initial, deeper-sourced eruption broke through a strong silicified aquitard cap. The soft ignimbrite collapsed during the second-phase eruption into the crater, to repeatedly choke the explosions causing short-term pressure rises that triggered ongoing deeper-sourced eruptions. The eruption spread laterally also by exploiting a local fault. These results are relevant for hydrothermal eruption hazard scenarios in environments where strong vertical variations in rock strength and porosity occur.
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: Ministry of Business, Innovation and Employment http://dx.doi.org/10.13039/501100003524
    Keywords: ddc:550.724 ; Hydrothermal eruptions ; Geothermal ; Champagne pool ; Experimental ; Eruption dynamics
    Language: English
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