Trap Material Research Articles

Accurate determination of volatile-flavor components in bos grunniens milk by high-throughput dynamic headspace gas chromatographic-mass spectrometry

A dynamic headspace (DHS) with DVB/CAR/PDMS trapping materials was coupled to a gas chromatography-mass spectrometry for the separation and identification of volatile-flavor compounds in bos grunniens (yak) milk. The principal components analysis coupled with response surface methodology optimized the main variables of the device (10 g sample quality, 5 min desorption time, 3.0 g adding sodium chloride, 72 °C extraction temperature, 28 min pre-equilibrium time and 86 min extraction time). Total 235 volatile components were identified. The limit of detections and quantifications of volatile components were 0.01–5.35 mg kg−1 and 0.01–9.41 mg kg−1, respectively, with relative standard deviation from 0.2% to 6.4%. The method performed well during volatile-flavor components analysis from the yak milk sample, producing excellent extraction parameters for the volatile components. Eighty-two volatile components identified in yak milk belonged to a broad range of chemical classes (ketones, aldehydes, aromatics, acids, alkanes, and estes), and 73 of them were at trace levels. Meanwhile, using gas chromatography-olfactometry technique, 11 volatile components were identified as contributors to the aroma of yak milk. In conclusions, a sensitive, convenient and reliable method was developed for the accurate determination of volatile-flavor compounds in yak milk utilizing DHS-GC/MS analyses.

Cyanobacteria and cyanophage contributions to carbon and nitrogen cycling in an oligotrophic oxygen-deficient zone

Up to half of marine N losses occur in oxygen-deficient zones (ODZs). Organic matter flux from productive surface waters is considered a primary control on N2 production. Here we investigate the offshore Eastern Tropical North Pacific (ETNP) where a secondary chlorophyll a maximum resides within the ODZ. Rates of primary production and carbon export from the mixed layer and productivity in the primary chlorophyll a maximum were consistent with oligotrophic waters. However, sediment trap carbon and nitrogen fluxes increased between 105 and 150 m, indicating organic matter production within the ODZ. Metagenomic and metaproteomic characterization indicated that the secondary chlorophyll a maximum was attributable to the cyanobacterium Prochlorococcus, and numerous photosynthesis and carbon fixation proteins were detected. The presence of chemoautotrophic ammonia-oxidizing archaea and the nitrite oxidizer Nitrospina and detection of nitrate oxidoreductase was consistent with cyanobacterial oxygen production within the ODZ. Cyanobacteria and cyanophage were also present on large (>30 μm) particles and in sediment trap material. Particle cyanophage-to-host ratio exceeded 50, suggesting that viruses help convert cyanobacteria into sinking organic matter. Nitrate reduction and anammox proteins were detected, congruent with previously reported N2 production. We suggest that autochthonous organic matter production within the ODZ contributes to N2 production in the offshore ETNP.

In situ Investigations of a Proton Trap Material: A PEDOT-Based Copolymer with Hydroquinone and Pyridine Side Groups Having Robust Cyclability in Organic Electrolytes and Ionic Liquids

A conducting redox polymer based on PEDOT with hydroquinone and pyridine pendant groups is reported and characterized as a proton trap material. The proton trap functionality, where protons are tra...

Role of Tidal Wetland Stability in Lateral Fluxes of Particulate Organic Matter and Carbon

AbstractTidal wetland fluxes of particulate organic matter and carbon (POM, POC) are important terms in global budgets but remain poorly constrained. Given the link between sediment fluxes and wetland stability, POM and POC fluxes should also be related to stability. We measured POM and POC fluxes in eight microtidal salt marsh channels, with net POM fluxes ranging between −121 ± 33 (export) and 102 ± 28 (import) g OM·m−2·year−1 and net POC fluxes ranging between −52 ± 14 and 43 ± 12 g C·m−2·year−1. A regression employing two measures of stability, the unvegetated‐vegetated marsh ratio (UVVR) and elevation, explained >95% of the variation in net fluxes. The regression indicates that marshes with lower elevation and UVVR import POM and POC while higher elevation marshes with high UVVR export POM and POC. We applied these relationships to marsh units within Barnegat Bay, New Jersey, USA, finding a net POM import of 2,355 ± 1,570 Mg OM/year (15 ± 10 g OM·m−2·year−1) and a net POC import of 1,263 ± 632 Mg C/year (8 ± 4 g C·m−2·year−1). The magnitude of this import was similar to an estimate of POM and POC export due to edge erosion (−2,535 Mg OM/year and − 1,291 Mg C/year), suggesting that this system may be neutral from a POM and POC perspective. In terms of a net budget, a disintegrating wetland should release organic material, while a stable wetland should trap material. This study quantifies that concept and demonstrates a linkage between POM/POC flux and geomorphic stability.

Ternary Memristic Effect of Trilayer-Structured Graphene-Based Memory Devices.

A tristable memory device with a trilayer structure utilizes poly(methyl methacrylate) (PMMA) sandwiched between double-stacked novel nanocomposite films that consist of 2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole (PBD) doped with graphene oxide (GO). We successfully fabricated devices consisting of single and double GO@PBD nanocomposite films embedded in polymer layers. These devices had binary and ternary nonvolatile resistive switching behaviors, respectively. Binary memristic behaviors were observed for the device with a single GO@PBD nanocomposite film, while ternary behaviors were observed for the device with the double GO@PBD nanocomposite films. The heterostructure GO@PBD/PMMA/GO@PBD demonstrated ternary charge transport on the basis of I–V fitting curves and energy-band diagrams. Tristable memory properties could be enhanced by this novel trilayer structure. These results show that the novel graphene-based memory devices with trilayer structure can be applied to memristic devices. Charge trap materials with this innovative architecture for memristic devices offer a novel design scheme for multi-bit data storage.

Aragonite dissolution kinetics and calcite/aragonite ratios in sinking and suspended particles in the North Pacific

The lack of consensus on CaCO3 dissolution rates and calcite to aragonite production and export ratios in the ocean poses a significant barrier for the construction of global carbon budgets. We present here a comparison of aragonite dissolution rates measured in the lab vs. in situ along a transect between Hawaii and Alaska using a 13C labeling technique. Our results show a general agreement of aragonite dissolution rates in the lab versus in the field, and demonstrate that aragonite, like calcite, shows a non-linear response of dissolution rate as a function of saturation state (Ω). Total carbon fluxes along the N. Pacific transect in August 2017, as determined using sediment traps, account for 11∼23 weight % of total mass fluxes in the upper 200 m, with a PIC (particulate inorganic carbon) /POC (particulate organic carbon) mole ratio of 0.2∼0.6. A comparison of fluxes at depths of 100 m and 200 m indicates that 30∼60% PIC dissolves between these depths with 20∼70% attenuation in POC fluxes. The molar ratio of PIC to POC loss is 0.29. The simultaneous loss of PIC and POC in the upper 200 m potentially indicates PIC dissolution driven by organic matter respiration, or metazoan/zooplankton consumption. The calcite/aragonite ratio in trap material is significantly lower in the subtropical gyre than in the subarctic gyre. Aragonite fluxes vary from 0.07 to 0.38 mmolm−2day−1 at 100 m, and 0.06 to 0.24 mmolm−2day−1 at 200 m along the North Pacific transect, with no specific trend over latitude. The identification of suspended PIC mineral phases by Raman spectroscopy shows the presence of aragonite below 3000 m in the subtropical gyre, but none in the subpolar gyre. These multiple lines of evidence suggest that predictions based on a strictly thermodynamic view of aragonite dissolution, combined with measured aragonite fluxes, underestimate observed alkalinity excess and measured PIC attenuation in sinking particles. Our measured aragonite flux combined with our inorganic dissolution rate only account for 9% and 0.2% of the excess alkalinity observed in the North Pacific (Feely et al., 2004), assuming aragonite sinking rates of 1 mday−1 and 100 mday−1, respectively. However, respiration-driven dissolution or metazoan/zooplankton consumption, indicated by the simultaneous attenuation of PIC and POC in sediment traps, is able to generate the magnitude of dissolution suggested by observed excess alkalinity.

Reply to Comment by F. Kenig, L. Chou, and D. J. Wardrop on “Evaluation of the Tenax Trap in the Sample Analysis at Mars Instrument Suite on the Curiosity Rover as a Potential Hydrocarbon Source for Chlorinated Organics Detected in Gale Crater” by Miller et al., 2015

AbstractKenig et al. comment on our 2015 reporting of laboratory analog experiments aimed at testing the stability of the hydrocarbon trap material used in the Sample Analysis on Mars (SAM) instrument on board the Curiosity Rover operating in Gale Crater on Mars. They propose chemical structures for some decomposition products of the Tenax TA polymer when it is exposed at high temperatures to the Cl2 and O2 gases formed by the thermal decomposition of perchlorate. Further, Kenig et al. propose that these decomposition products accumulate and then react further in cooler downstream sections of the SAM analytical pipeline to produce the chlorobenzene that was detected in the Cumberland mudstone of Gale Crater. However, numerous experiments conducted in the laboratory show that Tenax TA decomposition products only appear after repeated exposure to much higher levels of Cl2 and O2 than those seen by the flight instrument. Moreover, the sequence of chlorobenzene detections during gas chromatography‐mass spectrometry experiments conducted on Mars cannot be explained by Tenax TA decomposition, nor can the detection of chlorobenzene in Evolved Gas Analysis experiments that involve pathways devoid of Tenax TA. Kenig et al. are incorrect in their assertion that Tenax TA decomposition products can account for the chlorobenzene detected on Mars by SAM.

Tracing sinking organic matter sources in the NW Iberian upwelling system (NE Atlantic Ocean): Comparison between elemental, isotopic and molecular indicators

We studied the seasonal fluctuations in the composition of sinking particulate organic matter (POM) in the only upwelling-affected continental margin of Europe, to improve our understanding of the carbon (C) cycle of such systems. The methods employed targeted the elemental, stable isotope (δ13Coc and δ15N) and molecular (Py-GC-MS) composition. The results showed that the sinking POM in this margin is predominantly of marine origin, with δ15N (5.2 ± 0.3‰) and C/N (9.7 ± 1.0) values similar to those of marine plankton, and high abundances of pyrolysis products with isoprenoid structures, N-containing products from proteins (indoles, cyanobenzenes, etc.), and N-acetylated polysaccharides (acetamide, acetamidofurans) from chitin and peptidoglycan. Furthermore, the dataset demonstrates seasonal differences in POM composition under different oceanographic scenarios: i) dominance of most N-compounds, fatty acids and isoprenoid products during highly productive upwelling seasons, and ii) an increase in the relative abundance of linear alkanes/alkenes, phenols, lignin and PAH reflecting terrestrial influence during downwelling periods. In addition, the detection of isoprenoid alkylthiophenes traces (compounds formed under reducing conditions in the sediment) point to resuspended sediment in the trap material due to hydrodynamic effects of currents and waves on the seafloor. The results show that analytical pyrolysis is a useful tool for identifying different types of autochthonous and terrestrial POM, and therefore identification of the sources of sinking POM.

Obtaining the state of matter inside graphene nanobubble from its shape

Graphene nanobubble (GN) is a system consisting of the substrate, the graphene sheet and the substance trapped between them. Radius of GN regulates the pressure inside the bubble and for small GN with radius of several nanometers extreme pressures up to 1 GPa due to the van der Waals interaction can be observed. Therefore trapped substances inside GN can exist in a number of different states of matter. In this study we theoretically establish the connection between the shape of GN and the state of the trapped material inside. Both atomistic and continuum models are used to describe mechanical and thermodynamic properties of GN. Atomistic approach is applied to calculate the elastic constants and the adhesion energies. These parameters are used as inputs for the following analyses in terms of continuum media.

Effect of Pr3+ on Site Preferences of Eu2+ in NaBaScSi2O7 and Its Optical Properties

NaBaScSi2O7 with Eu2+ doped phosphors are prepared by high temperature solid state reaction. It is found that there are two different sites for Eu2+ occupied, which is responsible for different emission color of NaBaScSi2O7: Eu2+ with increasing Eu2+concentration. Pr3+ ions are introduced to regulate the Eu2+ ions occupied sites. When Pr3+ ions content climbs, conversion of blue to green emitting light can be realized because of the location migration of Eu2+ ions. Meanwhile, the defect structure of NaBaScSi2O7: Eu2+ has been adjusted by introducing Pr3+ ions, the shallow and deep traps generated benefits the long persistent luminescence (LPL) and photo-stimulated luminescence (PSL) phenomenon. It is interesting to note that NaBaScSi2O7: Eu2+, Pr3+ demonstrates different LPL and PSL color compared to NaBaScSi2O7: Eu2+. The controllable optical properties are realized on the basis of Eu2+ site preferences assisted by doping Pr3+, which provides guidance for the development of electron trapping materials.

Textured Hive Interiors Increase Honey Bee (Hymenoptera: Apidae) Propolis-Hoarding Behavior.

Numerous papers have shown that propolis contributes favorably to worker honey bee (Apis mellifera L.) immune response and colony social immunity. Moreover, resin-foraging specialists are more sensitive than pollen foragers to tactile information in the nest interior, and they respond to these stimuli by collecting more resin. In this study, we show that in-hive propolis deposition is increased, compared with nonmodified controls, with any one of the three methods for increasing textural complexity of hive wall interior surfaces: 1) plastic propolis trap material stapled to wall interior, 2) parallel saw kerfs cut into wall interior, or 3) roughening wall interior with a mechanized wire brush. Pairwise comparisons showed that propolis deposition was not significantly different among the three textural treatments; however, textural treatments interacted with time to show a more consistent benefit from plastic propolis trap material or roughened interior surface over saw kerfs. Although direct health benefits were not measured, this work shows that it is comparatively simple to increase propolis deposition above background levels by increasing textural stimuli in hive interiors.

Demonstration of α-InGaZnO TFT Nonvolatile Memory Using TiAlO Charge Trapping Layer

Amorphous indium gallium zinc oxide (α-InGaZnO) thin-film transistors using as nonvolatile memories (TFT-NVMs) with an Al2O3/TiAlO/Al2O3 charge trapping engineered structure have been demonstrated experimentally at low thermal budget of 300 °C. The high- k composite TiAlO layer with a high trap state density and a high dielectric constant was prepared by sputtering at room temperature as a charge trapping material. According to the high-resolution transmission electron microscopy analyses, the Al2O3/TiAlO/Al2O3 gate stack exhibited sharp interfaces and a uniform distribution of Ti and Al elements in the TiAlO film. The programming and retention characteristics of the fabricated α-InGaZnO TFT-NVMs were investigated in detail. The TFT-NVMs exhibited excellent programming characteristics with a large memory window of around 5.74 V under a 16 V programming voltage. It can also maintain a memory margin of about 5 V after 10 years, indicating only ∼15% charge loss. This paper suggests that α-InGaZnO TFT-NVMs using the high- k TiAlO composite material as the charge trapping material are promising for future nonvolatile memories applications in display technology, flexible and wearable electronics.

SUNSPACE, A Porous Material to Reduce Air Particulate Matter (PM).

The World Health Organization reports that every year several million people die prematurely due to air pollution. Poor air quality is a by-product of unsustainable policies in transportation, energy, industry, and waste management in the world's most crowded cities. Particulate matter (PM) is one of the major element of polluted air. PM can be composed by organic and inorganic species. In particular, heavy metals present in PM include, lead (Pb), mercury (Hg), cadmium, (Cd), zinc (Zn), nickel (Ni), arsenic (As), and molybdenum (Mo). Currently, vegetation is the only existing sustainable method to reduce anthropogenic PM concentrations in urban environments. In particular, the PM-retention ability of vegetation depends on the surface properties, related to the plant species, leaf and branch density, and leaf micromorphology. In this work, a new hybrid material called SUNSPACE (SUstaiNable materials Synthesized from by-Products and Alginates for Clean air and better Environment) is proposed for air PM entrapment. Candle burning tests are performed to compare SUNSPACE with Hedera Helix L. leafs with respect to their efficacy of reducing coarse and fine PM. The temporal variation of PM10 and PM2.5 in presence of the trapping materials, shows that Hedera Helix L. surface saturates more rapidly. In addition, the capability of SUNSPACE in ultrafine PM trapping is also demonstrated by using titanium dioxide nanoparticles with 25 nm diameter. Scanning electron microscope (SEM) and Transmission electron microscope (TEM) images of SUNSPACE after entrapment tests highlight the presence of collected nanoparticles until to about 0.04 mm in depth from the sample surface. N2 physisorption measurements allow to demonstrate the possibility to SUNSPACE regeneration by washing.

Assessing the air filtration efficacy of compressed and uncompressed polyurethane foams

The aim of this work was to assess the change in fungal spore filtration efficacy when conventional polyurethane foams were compressed to different ratios. Ninety PPI polyurethane foam samples of 30- and 50-mm thickness were produced, while different samples of 30-mm thickness were compressed to 5 and 25 mm. Air was drawn through foams in a set-up of manifold ports and spores were trapped onto the membrane filters. Micrographs of the polyurethane foams were also collected. An increase in the thickness of the foams resulted in a higher percentage of filtration efficacy. No observable change in the filtration efficiency of the foam was developed when the foam thickness was increased from 30 up to 50 mm. Compression, by reducing the pore size of the foam, allowed a more sinuous path for the air passing through the foam thus resulting in an increase in its trapping ability. Practical applications Compressed foam filters represent a possible way to control dust and microorganisms which can be dispersed in the air of food storage facilities, thus limiting the risk of product contamination. Such filters may find application, for instance, in postharvest warehouses in order to help producers limit the use of chemical treatments on fruit. Furthermore, a compressed polyurethane foam can be easily uncompressed by heating, so that it can be cleaned from the trapped material and compressed once again to be re-used. This could be of great advantage to cut down the production costs wherever air filters are used and need often to be replaced.

Medical activated charcoal tablets as a cheap tool for passive monitoring of gaseous 131I activity in air of nuclear medicine departments

It is well known that monitoring of radioactivity released from nuclear medicine departments is necessary to ensure the radiological safety of patients and personnel. Unfortunately, equipment for air sampling is often expensive, loud and is not suitable to use in hospitals. Our goal was to find cheap and simple system for passive monitoring of 131I activity concentration in the air of nuclear medicine departments. Medical activated charcoal tablets were used, because charcoal is excellent material for 131I trapping and tablets are readily available. Our proposed sampling protocol contains tablets preparation, exposure and measurements using HPGe detector. Different methods of tablets preparation (drying, impregnation with KI or NaOH) were tested while an experimental chamber was prepared for estimating 131I (released from Na131I, similar to that used in therapy) trapping efficiency of tablets in different conditions. Finally, tablets were placed in plastic holders and tested in nuclear medicine facilities.

Ultrathin HfO2-modified carbon nanotube films as efficient polysulfide barriers for Li-S batteries

Ultrathin and cross-stacked carbon nanotube (CNT) films modified with hafnium oxide (HfO2) by atomic layer deposition are employed as efficient polysulfide barriers for high performance Li-S batteries. A HfO2/CNT interlayer has an ultrathin, flexible structure with a thickness of 1.5 μm and an areal density of 0.087 mg cm−2, along with excellent wettability to electrolyte. The highly conductive CNT network and the catalytic surface adsorption of polysulfide species by HfO2 significantly suppress the polysulfides shuttling phenomenon. With high sulfur loadings of up to 75 wt%, electrodes incorporating a HfO2/CNT interlayer show noticeable improvements in various electrochemical properties, including long-term cycling stability (721 mA h g−1 after 500 cycles at 1 C), high rate performance (800 mA h g−1 at 5 C), favorable anti-self-discharge capabilities, and suppression of Li anode corrosion. These results suggest a new and efficient polysulfide trapping material and a viable configuration for high-performance Li-S batteries.

(Keynote) Pyrochemical Process in Molten Salts for Spent Nuclear Fuel Reprocessing and Radioactive Waste Treatments

The pyrochemical process in molten salts for spent nuclear fuel reprocessing and radioactive waste treatment has been developed since 1988. The pyrochemical process for metallic fuel reprocessing has been started using electrorefining. The electrowinning for spent oxide fuel in molten salts has been developed since 1994. The radioactive waste treatment such as metallic waste contaminated by uranium and chemical trap materials in uranium enrich plant, zirconium recycle for spent zircaloy waste from Light Water Reactors was based on the spent nuclear fuel reprocessing. A treatment process for fuel debris in Fukushima Daiichi Nuclear Power Plant recently has been developing. This paper reviews pyrochemical process for spent nuclear fuel reprocessing and radioactive waste treatment.

(Keynote) Pyrochemical Process in Molten Salts for Spent Nuclear Fuel Reprocessing and Radioactive Waste Treatments

The pyrochemical process in molten salts for spent fuel reprocessing and radioactive waste treatment has been developed since 1988. The pyrochemical process for metallic fuel reprocessing has been started using electrorefining. The electrowinning for spent oxide fuel in molten salts has been developed since 1994. The radioactive waste treatment such as treatment process of metallic waste contaminated by uranium and chemical trap materials in uranium enrich plant. Zirconium recycle for zircaloy waste from LWR was based on the spent fuel reprocessing. A treatment process for debris in Fukushima Daiichi Nuclear Power Plant recently has been just started. This paper reviews pyrochemical process for spent fuel reprocessing and radioactive waste treatment.

Method development and validation for total mercury determination in coke oven gas combining a trap sampling method with CVAAS detection

Coke oven gas is one of the by-products of the coal coking process. It is used as a fuel in the coking plant, but also as a raw material in the chemical industry to produce methanol, syngas or environment-friendly, low-CO2 hydrogen fuel. Due to the reasons mentioned above, the knowledge of coke oven gas pollutants such as mercury is a key issue. To determine the mercury in the cleaned coke oven gas a trap sampling method combined with CVAAS mercury detection was developed, optimized and validated. In order to perform the sampling process the traps filled with activated carbon were used. The determination of mercury in the traps material was performed by means of an MA-2 mercury analyzer. During the optimization of the method one selected the trap material, sample volume and flow rate. The optimal volume of the coke oven gas sample was 3 dm3 and the flow rate was 18 dm3/h (per one trap). The developed method was validated according to the Eurachem recommendation and was applied to determine mercury in the clean coke oven gas. The coke oven gas sampling was performed in a coking plant in Poland. The average concentration of mercury in the clean coke oven gas was 3.2 ± 0.3 μg/m3N (k = 2) for n = 18.

Role of the process conditions on the sulphation and stability of a CuO/SBA-15 type SOx adsorbent in cycling operations

SOx abatement is one of the major challenges for the industry with regards to the more stringent European regulations. Despite their good performance, current DeSOx technologies are energy-intensive and produce waste. Flue gas desulphurisation using SOx adsorbents thus is a viable alternative. However, the development of such a technology is still hampered by the adsorbent short lifetime within the wide range of conditions prevailing at the exhaust of combustion engines. In this work, a CuO/SBA-15 adsorbent was assessed as a SOx trap material under different sulphation conditions (temperature from 350 °C to 450 °C, gas composition (SO2: 250, 450 and 450 ppm; O2: 150 vol%), GHSV from 18,000 to 110,000 h−1 and sulphation time). The SO2 adsorption capacity of the adsorbent was greatly impacted by the temperature: the higher the temperature, the better the performance. Indeed, the dynamic adsorption capacity is equal to 31 mgSO2/gads, 37 mgSO2/gads and 52 mgSO2/gads at 350 °C, 400 °C and 450 °C respectively. Conversely, no significant changes in the SO2 dynamic adsorption capacity were observed whatever the SO2 and O2 molar fractions in the adsorption gas stream. The GHSV appears as a very sensitive parameter since the higher this parameter, the worse the adsorbent performance (e.g. for GHSV of 25,000 h−1, Cads = 37 mgSO2/gads; for GHSV of 50,000 h−1, Cads = 19 mgSO2/gads). Stabilised SO2 adsorption capacities along 25 cycles were obtained by regenerating before the breakthrough. Under these conditions, no SO2 emission occurs during the adsorption step, which represents the major technology block faced in any multicycle adsorption-based process over time.