Carbon Grains Research Articles

An attempt to determine the magnetic field configuration in the planetary nebula K 3-35 with ALMA

ABSTRACT We examined dust polarization within the planetary nebula (PN) K 3-35 using the Atacama Large Millimeter/Submillimeter Array (ALMA). This investigation aimed to identify and trace the magnetic field within the PN, as it potentially plays a crucial role in shaping this bipolar nebula. Our findings include a marginal detection of the polarized region and low fractional polarization (peaking at 1.4 per cent). Assuming a certain level of validity, we observed well-organized dust grains aligned along the equatorial plane of the PN, indicating a magnetic field alignment with the outflows. The limited detection of polarization at submillimeter wavelengths in this PN and others may be attributed to a pronounced optical depth. However, our analysis of K 3-35 with the code dusty does not seem to support this idea. We also modelled the Spectral Energy Distribution (SED) of K3-35, and our best-fitting models included a mixture of silicates and amorphous carbon. The grains of amorphous carbon are less susceptible to alignment with the magnetic field, which could, at least partially, explain the observed low polarization. The models presented in this article should be considered preliminary, and a more advanced approach is needed for a more complete interpretation of the results.

A Comparative Study of Gold Leaching Kinetics Using Alternative Reagents from Concentrates of Low-Grade Ores

This study compares gold leaching using sodium cyanide (NaCN) with alternative YX500 and Jinchan reagents. The research object was a gold–sulfide polymetallic ore (Republic of Kazakhstan) with a gold content of 0.38 g/t. The closed flotation beneficiation experiment resulted in a concentrate with an 81.40% recovery and a 5.3 g/t gold grade. The resulting concentrate was subjected to oxidizing roasting to completely oxidize the sulfides and mineral grains of arsenopyrite, pyrite, and carbon. A comparative evaluation of leaching showed that the gold recovery from the roasted concentrate using alternative YX500 and Jinchan reagent solutions was comparable to that using NaCN, with the recoveries at approximately the same level of 86.5%. The differential analysis of the obtained multiplicative multifactor Protodyakonov–Malyshev model made it possible to determine the apparent activation energy of the process using the Arrhenius equation, which eliminates the widely used graphical model. In the proposed method of kinetic experiment planning, the time differentiation of the Kolmogorov–Erofeev equation is mandatory, determining it as a partial dependence on the duration and multiplicative equation for all transformations to determine the activation energy of the process at any given conversion value and other operative factors. The variation range of the apparent value of the activation energy of the gold leaching process, from 0.718 to 78.0 kJ/mol, indicates that the limiting stage of this process is the solid-phase diffusion of CN ions from the outside to the center of the grain material.

Stress-Driven Grain Boundary Structural Transition in Diamond by Machine Learning Potential.

Understanding the structural dynamics of carbon grain boundaries, particularly in diamond, is essential for advancing next-generation device applications. Carbon's diverse allotropes, driven by its versatile chemical bonding, hold immense potential, yet analyzing these boundaries is challenging due to the limitations of experimental techniques and the computational demands of ab initio molecular dynamics simulations. In this study, a machine learning-based molecular dynamics potential, rigorously trained on ab initio data, that accurately predicts structural transitions in incoherent twin boundaries within diamond is introduced. This potential reveals the atomic-scale mechanisms driving these transitions and identifies an 80% reduction in interfacial thermal conductance during the grain boundary transition. These findings provide deep insights into the complex behavior of diamond grain boundaries, uncovering a novel mechanism that regulates thermal properties and paving the way for enhanced thermal management in diamond-based technologies.

Raman spectroscopic analysis of carbonates on a CY-type carbonaceous chondrite Yamato 980115: unexpectedly abundant terrestrial weathering products.

This study presents Raman spectra of carbonates on a carbonaceous chondrite, Yamato (Y) 980115. Y 980115 is an Antarctic meteorite and is originally classified as CI1-type. Since CI1-type meteorites are expected to record information of aqueous alteration of carbonaceous matters in the primitive solar photosphere or planetesimals, extensive studies have been performed. Among a variety of minerals on meteorites, carbonates are one of environment indicators because its cation composition depends on thermochemical properties of the aqueous solution when they were precipitated. Although the minerals on meteorites are usually identified by elemental composition analysis techniques such as backscattered electron imaging, these techniques have a drawback that they lack information of crystal structures so that it is difficult to distinguish some minerals such as ordered or disordered dolomite (CaMg(CO3)2) and a mixture of calcite (CaCO3) and magnesite (MgCO3). The present study employed Raman spectroscopy as a complementary technique to the elemental composition analysis. As a result, surprisingly, while the Mg-bearing carbonates on Y 980115 were expected mainly to be dolomite, the Raman spectra revealed that they are indeed nesquehonite (Mg(HCO3)(OH)·2H2O), which is a typical terrestrialweathering product for Antarctic meteorites. Among 63 carbonate grains found on Y 980115, 60 and 3 grains were assigned to nesquehonite and calcite, respectively, and no dolomite was found. This result indicates that there are unexpectedly abundant terrestrial weathering products for carbonates found on Y 980115.

Ayla Oasis Lagoons: A Model for Ecological Sustainability and Marine Conservation in Aqaba, Jordan

The Ayla Oasis in Aqaba, Jordan, is a major tourism and residential development project in Aqaba, Jordan, containing three artificial lagoons. This study explores the ecological sustainable development of Ayla Lagoons, focusing on the seawater and bottom sediment quality, and the bottom habitat, in addition to coral conservation and restoration initiatives. The flushing time, averaging 3.7 days for the Upper Lagoon and 2.4 days for the Middle Lagoon, plays a crucial role in maintaining water quality. These measures secure the well-being of all visitors and residents, while also preserving the marine biodiversity. The Upper, Middle, and Tidal Lagoons exhibit physiochemical properties in alignment with seawater characteristics of the Gulf of Aqaba. Sediment quality analysis shows organic carbon levels and grain size distribution vary among lagoons, indicating expected different energy conditions and a healthy environment. The lagoons support a diverse range of species, with a total of 2343 fish individuals belonging to 22 species across 17 families recorded. The comprehensive analysis of the Ayla Oasis lagoons’ seawater and sediment quality revealed a dynamic and resilient ecosystem. Ayla’s coral conservation and restoration initiative within its lagoons feature 166 reef balls, 5 coral nurseries, and 2 metal structures, all designed to foster marine biodiversity. The project demonstrates the effectiveness of Ayla Oasis’ environmental resilience and monitoring strategies, showcasing a commitment to sustainable management and environmental stewardship. These efforts reflect Ayla’s ongoing dedication to protecting and preserving the marine ecosystem, ensuring the long-term health of its coral reefs and surrounding marine life.

Dust evolution by chemisputtering during protostellar formation

Context. Dust grains play a crucial role in the modeling of protostellar formation, particularly through their opacity and interaction with the magnetic field. The destruction of dust grains in numerical simulations is currently modeled primarily by temperaturedependent functions. However, a dynamical approach could be necessary to accurately model the vaporization of dust grains. Aims. We focused on modeling the evolution of dust grains during star formation, specifically on the vaporization of the grains by chemisputtering. We also investigated the evolution of non-ideal magnetohydrodynamic resistivities and the Planck and Rosseland mean opacities influenced by the grain evolution. Methods. We modeled the evolution of the dust by considering spherical grains at thermal equilibrium with the gas phase, composed only of one kind of material for each grain. We then took into account the exchange processes that can occur between the grains and the gas phase and that make the grain size evolve. We considered three materials for the grains: carbon, silicate, and aluminum oxide. Given a temporal evolution in temperature and density of the gas phase, we computed the evolution of a dust grain distribution. This evolution was then used to compute the non-ideal magnetohydrodynamic resistivities and the Planck and Rosseland mean opacities. Results. We observed a significant dependence of the sublimation temperature of the carbon grains on the dynamical evolution of the gas phase. The application of our method to trajectories where the temperature and density of the gas decrease after the sublimation of a portion of the grain distribution highlights the limitations of current vaporization prescriptions in simulations. Conclusions. The dynamical approach leads to more accurate results for the carbon grain quantity when the temperature and density of the gas evolve quickly. The dynamical approach application to collapse and disk evolution is then foreseen with its integration into hydrodynamic simulations.

Fabrication of novel carbon nanofiber membrane microporous layer to improve water management ability of PEMFC

The issue of water flooding in proton exchange membrane fuel cells (PEMFC) under conditions of humidity levels leads to significant mass transfer losses. To address this challenge, a fiber-structured microporous layer (MPL) with high porosity is developed, and investigates the impact of carbon nanotube (CNT) on its heat treatment process. The inclusion of CNT facilitates the cyclization of polyacrylonitrile in the pre-oxidation process. Thereby reduces the fracture of nanofibers, improved the microstructure and the porosity of the membrane during carbonization. The carbon nanofiber membranes containing CNT shows a higher oriented arrangement of carbon grains after graphitization. The high porosity of the fiber membrane MPL confers exceptional mass transfer capabilities. At 100% RH, the MPL sample CFP-2C improves the maximum power density and a maximum current density of PEMFC by 47.5% and 55.3%, respectively, compares to the conventional carbon black particles MPL.

Air Bubbling Assisted Soil Washing to Treat PFAS in High Organic Content Soils

The soil-washing technique has been successfully utilized for the remediation of PFAS-contaminated soils. Prior studies have shown that the organic carbon (OC) content and grain size of soil determined the efficiency of PFAS removal during washing. However, most of the past studies have focused on soils with a low OC content, typically ranging from 0–3%. In this study, we explored the use of a novel process where soil washing was combined with air bubbling (or foam fractionation) to aid in the removal of PFAS from high OC-content soils (~4–20%). Treatment with air bubbling of high OC soil (~20%) with perfluorobutane sulfonate (PFBS) and perfluorooctanoate (PFOA) did not enhance their removal, as they featured low surface activity. However, we observed an improvement in the extraction of perfluorooctane sulfonate (PFOS) from 27% to 42% with bubbling, consistent with the higher surface activity of PFOS compared to PFOA and PFBS. Perfluorodecanoic acid (PFDA) was irreversibly adsorbed to the high OC soil and was not removed efficiently by both bubbling and soil washing. A slight improvement in PFDA removal (6–13%) was observed when a co-surfactant (cetyltrimethylammonium chloride) was added and when the OC content was reduced to ~4% by the addition of nonorganic sand to the contaminated soil prior to soil washing. This suggested that the interaction of PFDA with OC was the dominant factor determining its extraction from soil. In conclusion, our results indicated that soil washing alone was sufficient for the removal of short-chain PFAS from soil. Although bubbling had a mild effect on the removal of some long-chain PFAS from the solution, it did not help in the overall removal of PFAS from high OC soils, highlighting the difficulty in the treatment of high OC-content soils and that immobilization of PFAS would be an ideal approach in managing such contaminated sites.

The hidden role of heterotrophic bacteria in early carbonate diagenesis

Microbial impacts on early carbonate diagenesis, particularly the formation of Mg-carbonates at low temperatures, have long eluded scientists. Our breakthrough laboratory experiments with two species of halophilic aerobic bacteria and marine carbonate grains reveal that these bacteria created a distinctive protodolomite (disordered dolomite) rim around the grains. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) confirmed the protodolomite formation, while solid-state nuclear magnetic resonance (NMR) revealed bacterial interactions with carboxylated organic matter, such as extracellular polymeric substances (EPS). We observed a significant carbon isotope fractionation (average δ13C = 11.3‰) and notable changes in Mg/Ca ratios throughout the experiments. Initial medium δ13C was − 18‰, sterile sediments were at 2‰ (n = 12), bacterial-altered sediments were − 6.8‰ (n = 12), and final medium δ13C was − 4.7‰. These results highlight the role of bacteria in driving organic carbon sequestration into Mg-rich carbonates and demonstrate the utility of NMR as a tool for detecting microbial biosignatures. This has significant implications for understanding carbonate diagenesis (dissolution and reprecipitation), climate science, and extraterrestrial research.

Spatial Differences in Soil Nutrients Along a Hydrographic Gradient on Floodplains in Dongting Lake

The spatial heterogeneity of soil nutrients is crucial for the water bird and whole floodplain wetland ecosystem in large lakes, and it is influenced by the dramatic water level changes and sedimentation progress in West Dongting Lake (WDL). Soil samples were collected at various soil depths along the Yuan River and Li River that feed into WDL. The concentrations of soil total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), and soil grain size were tested. The stoichiometric ratios of C, N, P, and the mean value of soil grain size (Mz) were calculated. The differences of soil TOC, TN, TP and the stoichiometric ratio at different sites and soil depths were compared. Linear regression was used to explore the relationships of Mz and nutrient concentrations, and relationships between TOC, TN, and TP. Redundancy analysis was used to explore the relationship between soil nutrients, heavy metal concentrations, and plant community diversity. The results showed that the distributions of soil TOC, TN, and TP concentrations differed across regions in west Dongting Lake along the Yuan and Li Rivers. Total organic carbon concentration differed at different sedimentation depths. Soil grain size showed negative effect with soil TOC, TN, and TP concentrations in this region. Plant community diversity correlated positively with soil TOC and negatively with Hg. West Dongting Lake was N limited despite the high wet deposition of N. It could potentially be attributed to the insufficient presence of aerobic environments for microbes during intermittent flooding of the floodplain, coupled with feeble mineralization. This study can provide valuable insights for the conservation of water bird habitats and wetland ecosystems.

JWST/MIRI Detection of a Carbon-rich Chemistry in the Disk of a Solar Nebula Analog

It has been proposed, and confirmed by multiple observations, that disks around low-mass stars display a molecule-rich emission and carbon-rich disk chemistry as compared to their hotter, more massive solar counterparts. In this work, we present JWST Disk Infrared Spectral Chemistry Survey MIRI-MRS observations of the solar-mass star DoAr 33, a low-accretion rate T Tauri star showing an exceptional carbon-rich inner disk. We report detections of H2O, OH, and CO2, as well as the more complex hydrocarbons, C2H2 and C4H2. Through the use of thermochemical models, we explore different spatial distributions of carbon and oxygen across the inner disk and compare the column densities and temperatures obtained from LTE slab model retrievals. We find the best match to the observed column densities with models that have carbon enrichment, and the retrieved emitting temperature and area of C2H2 with models that have C/O = 2–4 inside the 500 K carbon-rich dust sublimation line. This suggests that the origin of the carbon-rich chemistry is likely due to the sublimation of carbon-rich grains near the soot line. This would be consistent with the presence of dust processing as indicated by the detection of crystalline silicates. We propose that this long-lived hydrocarbon-rich chemistry observed around a solar-mass star is a consequence of the unusually low M-star-like accretion rate of the central star, which lengthens the radial mixing timescale of the inner disk, allowing the chemistry powered by carbon grain destruction to linger.

Quantifying organic carbon burial rates and stocks in seagrass meadow sediments influenced by sargassum-brown tides

Quantifying organic carbon burial rates and stocks in seagrass meadow sediments influenced by sargassum-brown tides

From loose sand to sandstone: An experimental approach on early calcite precipitation in sands of siliciclastic and mixed carbonate-siliciclastic composition.

Artificially cemented sandstones were produced to assess the impact of detrital texture and composition on the precipitation and distribution of early calcite cement, and cement-related degradation in porosity. To simulate early-calcite cementation, loose sediment of variable composition (siliciclastic and calcareous) and grain size was exposed to a calcite supersaturated solution for 35 to 58 days at 23°C. Identification and distribution of the newly precipitated crystals was performed with high resolution 2D optical and scanning electron microscopy. The experimental results show the precipitation of grain-coating, pore-bridging and pore-filling granular calcite cement with up to 100 μm crystal size. Despite a positive correlation between the amount of detrital carbonate grains and calcite crystals, calcite cement does not preferentially nucleate on bioclast surfaces, irrespectively of their favourable mineralogy. Siliciclastic grains show high calcite cement coverage with altered feldspar, particularly plagioclase, displaying coverage of 94.3%. Grain size variations within the sand packs have influence on the precipitation pattern of calcite with coarse-grained layers (500-710 μm) showing minor calcite cementation (6.3%), while medium- (250-500 μm) to fine-grained layers (125-250 μm) comprise average calcite cement contents of 16.3% and 28.2%, respectively. The findings of this study enhance our knowledge regarding the precipitation processes of calcite in porous material with heterogeneous reacting mineral phases, shapes and pore connectivity.

Micro-facies characterization of the Cane Creek Shale, Paradox Basin, Utah: implications of diagenetic controls on reservoir quality

The fine-grained Pennsylvanian Cane Creek Shale of the Paradox Formation, Paradox Basin, Utah exhibits relatively thin cyclic interbeds of contrasting lithologies including fine sandstone to siltstone, organic-rich carbonate and dolomitic mudstone, and evaporites. As such, it provides a unique opportunity to evaluate micro-facies and the fluid storage capacity potential of mixed fine-grained systems. Micro-facies descriptions were performed using core and petrographic analyses, including scanning electron microscopy with energy dispersive spectroscopy. The study leverages core-based porosity and permeability data, as well as previous core description. These data are used together to explore mineralogical depositional and diagenetic controls on porosity and permeability. Twelve micro-facies were described based on sedimentological textures, grain size, lithology, and mineralogy categorized into three groups: 1) sandstone to siltstone, 2) mudstone, and 3) evaporitic micro-facies. Sandstone to siltstone micro-facies exhibit variable porosity and permeability. Porosity connectivity is dependent on the degree of authigenic cementation and compaction that negatively impacts porosity. Mudstone micro-facies show less variability in porosity and permeability; and are characterized by carbonate content, organic-matter, and clay nanopores. The development of early carbonate grains maintains porosity in mudstone and dolomitic siltstone micro-facies. Evaporitic micro-facies represented by evaporitic sabkha-like conditions are characterized by pore-reducing anhydrite and halite cement. A diagenetic paragenetic sequence was developed to assess the timing and impact of mineralogy on reservoir quality. Early (eogenetic), Middle (mesogenetic), and Late (telogenetic) stages correspond with diagenetic stages and known tectonic basin events. Syndepositional dolomite and diagenetic illite/smectite authigenic cements are the main controls on reservoir quality and have opposing effects related to porosity and permeability by preserving early pore space or reducing porosity and permeability.

Gold Mineralisation and their Lithological Controls at Nagavi Area, Gadag Schist Belt, in Karnataka, India

Dharwar craton is located in southern India is part of the Dharwar-Singhbhum proto-continent and is known for its complex tectonic and structural controls. It’s made up of two distinct parts, Western Dharwar Craton (WDC) and the Eastern Dharwar Craton (EDC) house several schist belts. Many of these schist belts, such as the Kolar schist belt, Hutti schist belt, Chitradurga schist belt and the Gadag schist belt, are auriferous. In such schist belts, gold occurs in association with sulphides such as pyrite, pyrrhotite, arsenopyrite and chalcopyrite. Gold mineralization in these belts is found to occur in different lithologies. The Gadag schist belt is composed dominantly of metabasalt in its western half and meta sediments in the eastern half. Quartz-carbonate veins are observed to cut across these lithologies as well as the Banded Iron Formations (BIFs). This paper aimed to study the gold mineralization in different lithologies of the Gadag schist belt and found that metabasalts and BIFs are the dominant rocks hosting gold. It is also observed that mineralization is strata-bound. Most of the places’ auriferous sheared zones were observed in the study area. In Nagavi area, BIF hosted gold mineralization is observed, and major gold concentration varies from <21 to <26 ppb (parts per billion). Pyrite occurs as characteristic cubic crystals and as clusters of small grains. In carbonated sheared anorthosite, the rock is fine to medium-grained and in-equigranular. It consists of simple to polysynthetically twinned subhedral (100-200 by 400-600 μm) laths (~40-45%) set in a groundmass of irregular anhedral grains of secondary carbonate (~35-40%), chlorite (~8-10%), opaque (~5-7%) and accessory epidote and quartz.

A new type of dolomicrite envelope formed in Oligocene lacustrine sediments and its significance for preserving porosity, Bohai Bay Basin, North China

A new type of dolomicrite envelope formed in Oligocene lacustrine sediments and its significance for preserving porosity, Bohai Bay Basin, North China

Micritisation products in the inner ramp settings of the Abu Dhabi Lagoon

AbstractIn numerous carbonate reservoirs in the Middle East, peloidal packstone‐grainstones are rock types with excellent pore storage potential in micritised microporous grains. However, the origin of the micro‐porosity and associated micro‐spar remains unclear, and one hypothesis is that both micro‐spar and porosity originate from early marine micritisation and were later altered during subsequent diagenesis (i.e. cementation recrystallisation). The south‐eastern coast of the Arabian Gulf is recognised as a modern, albeit miniature, depositional setting analogue to Mesozoic carbonate sequences that form the supergiant reservoirs of the Middle East. Using optical microscopy, backscattered scanning electron microscopy and carbon and oxygen stable isotope analysis the present study aims to document the nature of internal microstructures of micritic envelopes and peloids from the surface sediments of various sub‐environments of the Abu Dhabi Lagoon. Results highlight a high degree of diversity and heterogeneities of most micritic envelopes and peloids observed across the sub‐environments. First, carbonate grains from ooid and bioclastic shoals show the simpler micritic envelopes. Here, micritic envelopes and peloids show sparse microborings filled with banded radial aragonite cement, a pattern of production of cryptocrystalline texture (e.g. micritisation) that is similar to the sequence of micritisation observed in the modern sediment of the Great Bahama Bank. Conversely, in the subtidal and intertidal zones with mangroves or seagrass, the micritic envelopes and peloids are much more complex and show multiple generations of microborings that are either empty or filled with carbonate materials of varying types (i.e. various cements, fragments, etc.).

The rise of biogenic silicon cycling and microbial silicification promoted Mesoproterozoic chert deposition

The rise of biogenic silicon cycling and microbial silicification promoted Mesoproterozoic chert deposition

Infrared emissivity of icy surfaces

Context. Most analyses of the infrared emission of Saturn’s rings and icy satellites have considered pure water ice as the constituent of regolith and particle surfaces. Visual and near-infrared observations have shown, however, that darkening and reddening contaminants are present at a fraction level of a few percent. In the spectral domain 10–2000 cm−1, water ice becomes transparent in a few windows, which in particular causes the roll-off of emissivity of icy surfaces that is observed below 50 cm−1. Their emissivity there may be affected by these contaminants. Aims. We present a quantitative global sensitivity analysis of a hybrid Mie-Hapke model to evaluate the influence of regolith properties and contaminant fraction on the infrared emissivity of icy rings or moons over this spectral range. Methods. A hybrid Mie–Hapke model of the hemispherical emissivity ε*h(Wn) was made, including various diffraction correction and mixing types with tholins or amorphous carbon grains, or grain size distributions and some anisotropy in emission. A Sobol global sensitivity analysis provided quantitative levels of importance for these factors versus wave number wn. Results. Given the a priori uncertainties, the most important factor acting on ε*h(Wn) remains the size distribution of regolith grains and the average anisotropy factor ξ. For wn> 50 cm−1, ξ, the power-law index p and the minimum amin of the size distribution are most influential. In windows of water-ice transparency (10–50, 300–600, and 900–1300 cm−1), the emissivity is also sensitive, but to a lesser extent, to the maximum grain size amax and the fraction f of contaminants, if mixed at the molecular level. Conclusions. This model provides a self-consistent tool for interpreting multi-modal observations of the thermal emission from icy surfaces. It also offers interesting insights into recent mid-infrared observations of Saturn’s rings and Jupiter’s moon Ganymede by the JWST-MIRI instrument.

Experimental sticking coefficients of CO and N_2 on sub-micrometric cosmic grain analogs

Measuring the sticking coefficient of molecules pertinent to astrochemistry - such as CO - on substrates that mimic interstellar dust grains is crucial for the comprehensive understanding of gas-grain chemical processes. Although astrochemical models assume a sticking coefficient of 1, recent laboratory experiments on H2O and CO2 have revealed significantly lower values when measured on small grain analogs. As the effect of grain size on molecular adsorption has been largely ignored to date, further experiments are needed to determine the accretion rates of species known to freeze out on dust grains. Our aim is to determine the sticking coefficients of CO and N2 on sub-micrometric silicate and carbon grains. By quantifying realistic sticking coefficients on these dust grain analogs, we can improve the accuracy of astrochemists' predictions of molecular abundances as affected by gas-grain interactions. The molecules of interest were added to various substrates at 10 K in an ultra-high vacuum. The amount of adsorbate that stuck to the substrate was quantified using X-ray photoelectron spectroscopy. These quantities were compared to a reference with a sticking coefficient of 1, allowing the deduction of the sticking coefficient for each substrate. The average sticking coefficients of CO and N2 on grain analogs are 0.17 for CO and 0.14 for N2 on olivine powder, and 0.05 for CO and 0.07 on N2 on soot, instead of the presumed 1. This is in line with the low values previously reported for H2O and CO2 These laboratory results indicate that CO and N2 in addition to H2O and CO2 also exhibit a low sticking coefficient on dust grain analogs. It is thus necessary to reconsider the interactions between gaseous species and dust particles as a low-efficiency process. This reduction in accretion and reaction rates has important implications for how we understand astrochemistry.