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3D LIBS analysis provides insight into interaction of molten salts with nuclear grade graphites, including fluorine and other low-Z elements, through principal component and emission correlation analysis, as well as emission mapping/profiling.

Polygranular nuclear graphite, manufactured at 2800–3000 °C from a carbonized filler and binder mix, has high graphitization degree, crystalline structure close to perfect graphite, and about 20% porosity. The pore surfaces expose large regions of rough, defective prismatic edges of graphite crystallites which are the locus of graphite materials surface sites active for oxidation, chemisorption, and electron transfer. However, we show that high-resolution N2 and Kr first monolayer adsorption on polygranular graphite (P/P0

An electron microscopy investigation was performed to understand the relationship between the microstructure and properties of carbonized cellulose and lignin (softwood kraft lignin) relative to the structure of the original biomass components. Structure details at micro- and molecular levels were investigated by scanning transmission electron microscopy. Atomic-resolution images revealed the presence of random disordered carbon in carbonized cellulose (C-CNC) and of large domains of well-ordered carbon with graphite sheet structure in carbonized lignin (C-Lignin). These structural differences explain why C-CNC exhibits higher surface area and porosity than C-Lignin. The presence of certain well-ordered carbon in carbonized lignin indicates some of the carbon in lignin are graphitized with heat treatment temperature up to 950 °C. This result is encouraging for future endeavors of attaining acceptable modulus of carbon fiber from lignin given suitable modifications to the chemistry and structure of lignin. The results of this research contribute to an improved understanding of the carbonization mechanism of the key cellulose and lignin components of biomass materials.

The results obtained from a drying experiment using infrared heating are compared to those obtained from an analytical model based on correlations for the mass transfer coefficients, which are commonly used to obtain evaporation rates for drying applications. It was shown that the mass transfer coefficients calculated by natural convection correlations are approximately ten times lower than those measured under infrared (IR) exposure. In an attempt to explain this discrepancy, which has been also observed in other studies and explained on the basis of thermal radiation effects, optical properties of the solvent are presented and the implications of the IR and near infrared (NIR) spectrum on the thermal radiation effects and ensuing evaporation rates are discussed. The results show that the correlation for mass transfer coefficient has to take into account the IR radiation temperature and the surface emissivity. This study provides important evaporation data on mass flux and mass transfer coefficients, which cannot be predicted using traditional correlations, for the design of IR assisted drying systems.

Silicon carbide is widely appreciated for its high temperature strength, radiation tolerance and neutronic transparency in applications for fuel particles and core internals of nuclear reactors. In the Fluoride Salt-Cooled High Temperature Reactor, silicon carbide ceramic matrix composites are candidate construction material for regions of higher neutron fluxes. Silicon carbide is wettable and reacts electrochemically with dissolved metals. Metallic impurities, tritium, moisture-based impurities and fission products, as well as thermal gradients can accelerate hot corrosion of silicon carbide in molten fluoride salt. Tritium can become trapped in radiation defects of silicon carbide. Thus, an understanding of the potential for tritium absorption, impurities reactions and thermal gradient-assisted corrosion mechanisms along with tritium recovery and redox control systems are necessary to mitigate silicon carbide corrosion in molten fluoride salt systems. Here, we survey current research on silicon carbide corrosion in molten fluoride salts and critically evaluate the research and development gaps.

Molten salt reactors (MSRs) are being considered as one of the potential nuclear options to meet future energy demands. While the MSR designs are drastically different from the more traditional light water reactor, many of the waste streams are similar between the concepts. The purpose of this paper is to outline strategies for the treatment and processing of MSR-type wastes from concepts of reconditioning and recycle of certain components to partitioning and direct immobilization of other waste components. To help bridge science and technology gaps, knowledge gained from similar efforts such as pyroprocessing of Experimental Breeder Reactor II salt wastes can be leveraged to develop concept-to-disposition pathways.

The CERN IT Storage Group ensures the symbiotic development and operations of storage and data transfer services for all CERN physics data, in particular the data generated by the four LHC experiments (ALICE, ATLAS, CMS and LHCb). In order to accomplish the objectives of the next run of the LHC (Run-3), the Storage Group has undertaken a thorough analysis of the experiments’ requirements, matching them to the appropriate storage and data transfer solutions, and undergoing a rigorous programme of testing to identify and solve any issues before the start of Run-3. In this paper, we present the main challenges presented by each of the four LHC experiments. We describe their workflows, in particular how they communicate with and use the key components provided by the Storage Group: the EOS disk storage system; its archival back-end, the CERN Tape Archive (CTA); and the File Transfer Service (FTS). We also describe the validation and commissioning tests that have been undertaken and challenges overcome: the ATLAS stress tests to push their DAQ system to its limits; the CMS migration from PhEDEx to Rucio, followed by large-scale tests between EOS and CTA with the new FTS “archive monitoring” feature; the LHCb Tier-0 to Tier-1 staging tests and XRootD Third Party Copy (TPC) validation; and the erasure coding performance in ALICE.

Oxidation of nuclear graphites produces microstructural changes that affect the elastic moduli of these materials. It is widely accepted that the primary effect of oxidation is to increase porosity, but the related effect on the moduli cannot be explained satisfactorily by simply noting changes to porosity. In this work, models describing the elastic moduli of porous, polycrystalline graphite materials are developed to interpret experimental determinations of Young's modulus and shear modulus in two grades of nuclear graphite – IG-110 and NBG-18 – that were oxidized to produce varying levels of porosity. Experimental measurements were carried out using laser-based ultrasonic methods and were interpreted successfully using models that take into account the effects of preferential oxidation of different elements of the graphite microstructure. The results indicate the importance of the processes that lead to increased porosity since these can heavily influence the nature of the resulting structure-property relationships.

Microstructural changes induced by neutron irradiation of superfine grain graphite G347A (Tokai Carbon, Japan) were examined by nitrogen adsorption at 77 K and by three microscopy techniques (SEM, TEM and FIB-SEM tomography). The specimens were irradiated at doses of up to 30 dpa, covering stages before and after the turnaround fluence at three temperatures (300, 450, 750 °C) of their irradiation envelope. The initial graphite densification at low fluences did not produce any detectable effect in the pore size range ( 50 nm) at high irradiation fluences and more structural changes on multiple scales, from nanometers to microns. This work demonstrates the unique ability of gas adsorption techniques to analyze open pores with sizes between sub-nanometer and sub-micron in bulk nuclear graphite, with supporting microscopy results.

This manuscript provides raw nitrogen gas adsorption data, images and videos obtained from a technique that combines Focused Ion Beam (FIB) and Scanning Electron Microscopy (SEM) known as FIB-SEM tomography and Transmission Electron Microscopy (TEM) micrographs. This collection of data is useful for characterization of the effects of high fluence neutron irradiation in nuclear graphite as described in the associated manuscript, “Mesopores development in superfine grain graphite neutron-irradiated at high fluence” (Contescu et al., 2019). Nitrogen adsorption isotherms at 77 K are provided for graphite samples before and after neutron irradiation at 300, 450, and 750 °C at fluences before and after turnaround. FIB-SEM tomography reveals porosity of unirradiated and irradiated samples. Using this technique, four data sets were obtained, of which the first three are presented in video format, whereas the fourth one is a series of images provided in raw format unique to this manuscript. All microscopy data document the microstructure, surface area and porosity of superfine grain graphite G347A (Tokai Carbon, Japan) before irradiation and irradiated after turnaround at 400 °C. TEM micrographs provide unique information on irradiation damage at high neutron fluence (>27. 8 displacements per atom, dpa) in the microstructure and crystal lattice of graphite. Additional TEM micrographs are provided here, which do not duplicate the research paper published elsewhere (Contescu et al., 2019). These data sets are unique, as samples at high irradiation doses have never been measured or imaged before with the aforementioned techniques.

Understanding “Where?” and “How much?” oxidation has occurred in a nuclear graphite component is critical to predicting any deleterious effects to physical, mechanical, and thermal properties. A key factor in answering these questions is characterizing the effective mass transport rates of gas species in nuclear graphites. Effective gas diffusion coefficients were determined for twenty-six graphite specimens spanning six modern grades of nuclear graphite. A correlation was established for the majority of grades examined allowing a reasonable estimate of the effective diffusion coefficient to be determined purely from an estimate of total porosity. The importance of Knudsen diffusion to the measured diffusion coefficients is also shown for modern grades. Knudsen diffusion has not historically been considered to contribute to measured diffusion coefficients of nuclear graphite.

The production of biodiesel by the esterification of oleic acid, as an example of free fatty acid (FFA), was explored by using a new solid acid catalyst derived from lignin, a highly abundant low-cost biomass material. The catalyst was synthesized from lignin-derived carbon fiber by straightforward sulfonation and contains 1.86 mmol/g of sulfonic acid (-SO3H) groups. The catalyst was characterized by a variety of techniques including PXRD, TGA, TPD-MS, SEM, and XPS to understand the surface chemistry and the result of sulfonation. It was found that the sulfonated lignin-derived carbon fiber (CF-SO3H) catalyst was very efficient at esterifying oleic acid at 80 oC in 4 hours, with 10 wt. % catalyst (in terms of oleic acid content) and at a 10:1 molar ratio of methanol: oleic acid with a yield of 92%. Furthermore, the catalyst can be reused with no significant loss in activity after 4 cycles. Hence, synthesizing solid acid catalysts from lignin-derived carbon fiber affords a novel strategy for producing biodiesel via ‘green chemistry’.

Four grades of nuclear graphite were oxidized in helium with traces of moisture and hydrogen in order to evaluate the effects of slow oxidation by moisture on graphite components in high temperature gas cooled reactors. Kinetic analysis showed that the Langmuir-Hinshelwood (LH) model cannot consistently reproduce all results. In particular, at high temperatures and water partial pressures, oxidation was always faster than the LH model predicts. It was also found empirically that the apparent reaction order for water has a sigmoid-type variation with temperature which follows the integral Boltzmann distribution function. This suggests deviations from the LH model are apparently caused by activation with temperature of graphite reactive sites, which is probably rooted in specific structural and electronic properties of graphite. A semi-global kinetic model was proposed, whereby the classical LH model was modified with a temperature-dependent reaction order for water. This new Boltzmann-enhanced Langmuir-Hinshelwood (BLH) model consistently predicts oxidation rates over large ranges of temperature (800–1100 °C) and partial pressures of water (3–1200 Pa) and hydrogen (0–300 Pa). The BLH model can be used for modeling chronic oxidation of graphite components during life-time operation in high- and very high temperature advanced nuclear reactors.

Here we report a phase transition in H2 adsorbed in a locally graphitic Saran carbon with subnanometer pores 0.5-0.65 nm in width, in which two layers of hydrogen can just barely squeeze, provided they pack tightly. The phase transition is observed at 75 K, temperatures far higher than other systems in which an adsorbent is known to increase phase transition temperatures: for instance, H2 melts at 14 K in the bulk, but at 20 K on graphite because the solid H2 is stabilized by the surface structure. Here we observe a transition at 75 K and 77-200 bar: from a low-temperature, low-density phase to a high-temperature, higher density phase. We model the low-density phase as a monolayer commensurate solid composed mostly of para-H2 (the ground nuclear spin state, S = 0) and the high-density phase as an orientationally ordered bilayer commensurate solid composed mostly of ortho-H2 (S = 1). We attribute the increase in density with temperature to the fact that the oblong ortho-H2 can pack more densely. The transition is observed using two experiments. The high-density phase is associated with an increase in neutron backscatter by a factor of 7.0 ± 0.1. Normally, hydrogen produces no backscatter (scattering angle >90°). This backscatter appears along with a discontinuous increase in the excitation mass from 1.2 amu to 21.0 ± 2.3 amu, which we associate with collective nuclear spin excitations in the orientationally ordered phase. Film densities were measured using hydrogen adsorption. No phase transition was observed in H2 adsorbed in control activated carbon materials.

For the next generation of nuclear reactors, HTGRs specifically, an unlikely air ingress warrants inclusion in the license applications of many international regulators. Much research on oxidation rates of various graphite grades under a number of conditions has been undertaken to address such an event. However, consequences to the reactor result from the microstructural changes to the graphite rather than directly from oxidation. The microstructure is inherent to a graphite's properties and ultimately degradation to the graphite's performance must be determined to establish the safety of reactor design. To understand the oxidation induced microstructural change and its corresponding impact on performance, a thorough understanding of the reaction system is needed. This article provides a thorough review of the graphite-molecular oxygen reaction in terms of kinetics, mass and energy transport, and structural evolution: all three play a significant role in the observed rate of graphite oxidation. These provide the foundations of a microstructurally informed model for the graphite-molecular oxygen reaction system, a model kinetically independent of graphite grade, and capable of describing both the observed and local oxidation rates under a wide range of conditions applicable to air-ingress.

We report results of vibrational neutron spectroscopy investigation aimed to identify the state of hydrogen adsorbed in ultramicroporous carbon. The mobility of hydrogen confined in carbon pores was probed as a function of temperature and pressure using inelastic neutron scattering, and the molecular translational and rotational motions were studied. At low loading rotation of H 2 molecules adsorbed in the smallest carbon pores (∼4–5 A) is severely hindered, suggesting that the interaction between H 2 and the host matrix is anisotropic. At higher loading, H 2 molecules behave as a nearly free rotor, implying lower anisotropic interactions with adsorption sites. At 77 K where bulk H 2 is a gas, deconvolution of elastic/quasielastic signal provide evidence of pressure-dependent fractions of immobile (solid-like) and partially mobile (liquid-like) hydrogen, which correlate with the excess adsorption isotherm at 77 K. Effective H 2 density in pores changes from solid-like to liquid-like with increasing pressure at 77 K. Surprisingly, immobile and partially mobile H 2 is present even at temperatures as high as ∼110 K where bulk hydrogen exists only in gas form.

Laser ultrasonic line source methods have been used to study elastic anisotropy in nuclear graphites by measuring shear wave birefringence. Depending on the manufacturing processes used during production, nuclear graphites can exhibit various degrees of material anisotropy related to preferred crystallite orientation and to microcracking. In this study, laser ultrasonic line source measurements of shear wave birefringence on NBG-25 have been performed to assess elastic anisotropy. Laser line sources allow specific polarizations for shear waves to be transmitted – the corresponding wavespeeds can be used to compute bulk, elastic moduli that serve to quantify anisotropy. These modulus values can be interpreted using physical property models based on orientation distribution coefficients and microcrack-modified, single crystal moduli to represent the combined effects of crystallite orientation and microcracking on material anisotropy. Ultrasonic results are compared to and contrasted with measurements of anisotropy based on the coefficient of thermal expansion to show the relationship of results from these techniques.

Three advanced nuclear power systems use liquid salt coolants that generate tritium and thus face the common challenges of containing and capturing tritium to prevent its release to the environment...

Serving both as a structural and as a functional material, nuclear graphites have a range of useful mechanical, chemical and radiation-related behaviors that are important for nuclear applications. The raw materials used as feedstock along with the manufacturing processes used for production of these materials results in a complicated microstructure composed of graphite filler, graphitized pitch binder, and voids/defects that include porosity and microcracks. These heavily influence the overall elastic moduli of nuclear graphites and must be taken into account when interpreting ultrasonic measurements. Indeed, the measured elastic moduli are generally close to the Reuss limits – the theoretical, lower bounds for the moduli – but no attempts have been made to explain these results within the broader context of elasticity in porous materials containing microcracks. In this work, we report ultrasonic measurements of elastic moduli for nuclear graphites as a function of the bulk porosity and interpret them using relatively simple, physics-based models that describe the effects of porosity and microcracking on modulus. Modifications to these models are explored to account for microstructure-related effects on modulus such as those that are associated with oxidation-induced porosity. These models can be used to interpret a broad range of ultrasonic measurements reported previously for nuclear graphites, and the insight gained into the elastic responses of these materials can be used to guide the use of ultrasonic methods to assess the structural integrity of nuclear graphites.

Supercritical water is a green solvent used in many technological applications including materials synthesis, nuclear engineering, bioenergy, or waste treatment and it occurs in nature. Despite its relevance in natural systems and technical applications, the supercritical state of water is still not well understood. Recent theories predict that liquid-like (LL) and gas-like (GL) supercritical water are metastable phases, and that the so-called Widom line zone is marking the crossover between LL and GL behavior of water. With neutron imaging techniques, we succeed to monitor density fluctuations of supercritical water while the system evolves rapidly from LL to GL as the Widom line is crossed during isobaric heating. Our observations show that the Widom line of water can be identified experimentally and they are in agreement with the current theory of supercritical fluid pseudo-boiling. This fundamental understanding allows optimizing and developing new technologies using supercritical water as a solvent., Supercritical water exists in gas- and liquid-like forms, but these have not been distinguished yet at the macroscale. Here the authors investigate supercritical water interacting with microporous carbon by neutron imaging, and observe the coexistence of gas- and liquid-like states upon crossing the Widom line.

Even when not functionalized intentionally, most carbon materials are not hydrophobic and readily adsorb water molecules from atmospheric water vapor. We have equilibrated an ultramicroporous carbon at several levels of relative humidity, thereby attaining various hydration levels. The water molecules were adsorbed on the pore walls (but did not fill completely the pore volume) and thus could be better described as hydration, or surface, rather than confined, water. We used quasielastic neutron scattering to perform a detailed investigation of the dependence of microscopic dynamics of these adsorbed water species on the hydration level and temperature. The behavior of hydration water in ultramicroporous carbon clearly demonstrates the same universal traits that characterize surface (hydration) water in other materials that are surface-hydrated. Thus, unless special treatment is intentionally applied to ultramicroporous carbon, the species filling its pores in various applications, ranging from hydrogen molecules to electrolytes, likely find themselves in contact with non-freezing water molecules characterized by rich microscopic dynamics.

Laser ultrasonic methods have been used to measure the elastic moduli of various nuclear graphites. Measurements were made to assess wavespeeds for longitudinal and shear waves in different propagation directions and these were used along with density measurements to compute the longitudinal and shear moduli as well as Young's modulus. All moduli decreased with increasing graphite porosity and these variations could be interpreted using models describing the effect of porosity on material stiffness. Extrapolations for these models to zero porosity were used to infer the moduli for theoretically dense graphite; the results were far below predicted values reported in the literature for fully dense, polycrystalline, isotropic graphite. Differences can be attributed to microcracking in the graphite microstructure. Using models for the effects of microcracking on modulus, estimates for microcrack populations indicate that the number of cracks per unit volume must be much greater than the number of pores per unit volume. Experimental results reported in the literature for irradiated graphites as well as for the stress dependence of graphite modulus are consistent with the influence of microcracking on elastic behavior and could be interpreted using concepts developed here. Results in this work for graphite structure-property relationships should allow for more sophisticated characterization of nuclear graphites using ultrasonic methods.

The reactor core, moderator and reflectors of a thermal spectrum advanced molten salt reactor will constitute multi-tons of graphite. Porous reactor-grade graphite, if unprotected, can be permeated by molten salt depending on the infiltrating pressure differential and entrance diameters of accessible graphite pores. Salt and gas permeation of graphite can affect microstructural properties and radiation behavior but also facilitate diffusion, deposition and retention of fission products and tritium. Because of the significant void volume of nuclear graphite, fission products and tritium retention due to salt permeation necessitates seal coatings or pore impregnation to reduce open porosity. Alternatively, very fine-grained graphite grades with low Xe permeability are being developed. Here, we survey the current technologies for mitigating salt and gas transport into graphite.

The CERN IT Storage group operates multiple distributed storage systems and is responsible for the support of the infrastructure to accommodate all CERN storage requirements, from the physics data generated by LHC and non-LHC experiments to the personnel users' files. EOS is now the key component of the CERN Storage strategy. It allows to operate at high incoming throughput for experiment data-taking while running concurrent complex production work-loads. This high-performance distributed storage provides now more than 250PB of raw disks and it is the key component behind the success of CERNBox, the CERN cloud synchronisation service which allows syncing and sharing files on all major mobile and desktop platforms to provide offline availability to any data stored in the EOS infrastructure. CERNBox recorded an exponential growth in the last couple of year in terms of files and data stored thanks to its increasing popularity inside CERN users community and thanks to its integration with a multitude of other CERN services (Batch, SWAN, Microsoft Office). In parallel CASTOR is being simplified and transitioning from an HSM into an archival system, focusing mainly in the long-term data recording of the primary data from the detectors, preparing the road to the next-generation tape archival system, CTA. The storage services at CERN cover as well the needs of the rest of our community: Ceph as data back-end for the CERN OpenStack infrastructure, NFS services and S3 functionality; AFS for legacy home directory filesystem services and its ongoing phase-out and CVMFS for software distribution. In this paper we will summarise our experience in supporting all our distributed storage system and the ongoing work in evolving our infrastructure, testing very-dense storage building block (nodes with more than 1PB of raw space) for the challenges waiting ahead.

Graphite serves as the neutron moderator of British Gas-Cooled Reactors and is a candidate material for the Generation IV of nuclear power stations. The neutron irradiation affects the crystalline structure of graphite; this damage results in volumetric changes of the bulk material and generation of porosity. Dimensional changes induced by irradiation in graphite bricks can make difficult the refueling operations and reduce the stability of the graphite core. Some of the neutron irradiation damage mechanisms in the crystal lattice of graphite are not well understood. Results of TEM, SEM, FIB-SEM tomography, gas adsorption and optical microscopy will be combined to help understand how the irradiation affects graphite at multiple length scales. Furthermore, some new evidence of porosity and microstructural changes generated by irradiation will be presented.

The high pressure adsorption behavior of CO2 at T = 296 K in microporous carbon was investigated by small-angle neutron scattering (SANS) technique. A strong densification of CO2 in micropores accompanied by non-monotonic adsorption-induced pore deformation was observed. The density of confined CO2 increases rapidly with pressure and reaches the liquid –like density at 20 bar, which corresponds to the relative pressure of P/Psat∼0.3. At P > 20 bar density of confined CO2 increases slowly approaching a plateau at higher pressure. The size of micropores first increases with pressure, reaches a maximum at 20 bar, and then decreases with pressure. A complementary SANS experiment conducted on the same microporous carbon saturated with neutron-transparent and non-adsorbing inert gas argon shows no deformation of micropores at pressures up to ∼200 bars. This result demonstrates that the observed deformation of micropores in CO2 is an adsorption-induced phenomenon, caused by the solvation pressure - induced strain and strong densification of confined CO2.

Here we report a phase transition in H

Structure-property relationships in bulk materials can be important in establishing sensing methods to assess the state of material microstructure. This is particularly true for nuclear graphites since these materials can display anisotropy and can become oxidized under service conditions. Both anisotropy and oxidation-induced porosity can influence structural integrity and this must be confirmed during the lifetime of the material. In this work, laser ultrasonic methods were used to measure the elastic response of various graphite grades with a focus on NBG-18, NBG-25 and IG-110. Results of laser ultrasonic measurements in oxidized graphites show that the moduli decrease with increasing porosity. This variation can be interpreted successfully using effective medium models if the characteristics of graphite porosity are taken into account. Results of laser ultrasonic shear wave birefringence measurements can be used to assess elastic anisotropy. This anisotropy can be expressed in terms of the orientation distribution coefficients W 400 and W 200 . Interpretation of results requires the use of appropriate property-averaging schemes.

The CERN IT Storage group operates multiple distributed storage systems to support all CERN data storage requirements: the physics data generated by LHC and non-LHC experiments; object and file storage for infrastructure services; block storage for the CERN cloud system; filesystems for general use and specialized HPC clusters; content distribution filesystem for software distribution and condition databases; and sync&share cloud storage for end-user files. The total integrated capacity of these systems exceeds 0.6 Exabyte.Large-scale experiment data taking has been supported by EOS and CASTOR for the last 10+ years. Particular highlights for 2018 include the special HeavyIon run which was the last part of the LHC Run2 Programme: the IT storage systems sustained over 10GB/s to flawlessly collect and archive more than 13 PB of data in a single month. While the tape archival continues to be handled by CASTOR, the effort to migrate the current experiment workflows to the new CERN Tape Archive system (CTA) is underway.Ceph infrastructure has operated for more than 5 years to provide block storage to CERN IT private OpenStack cloud, a shared filesystem (CephFS) to HPC clusters and NFS storage to replace commercial Filers. S3 service was introduced in 2018, following increased user requirements for S3-compatible object storage from physics experiments and IT use-cases.Since its introduction in 2014N, CERNBox has become a ubiquitous cloud storage interface for all CERN user groups: physicists, engineers and administration. CERNBox provides easy access to multi-petabyte data stores from a multitude of mobile and desktop devices and all mainstream, modern operating systems (Linux, Windows, macOS, Android, iOS). CERNBox provides synchronized storage for end-user’s devices as well as easy sharing for individual users and e-groups. CERNBox has also become a storage platform to host online applications to process the data such as SWAN (Service for Web-based Analysis) as well as file editors such as Collabora Online, Only Office, Draw.IO and more. An increasing number of online applications in the Windows infrastructure uses CIFS/SMB access to CERNBox files.CVMFS provides software repositories for all experiments across the WLCG infrastructure and has recently been optimized to efficiently handle nightlybuilds. While AFS continues to provide general-purpose filesystem for internal CERN users, especially as $HOME login area on central computing infrastructure, the migration of project and web spaces has significantly advanced.In this paper, we report on the experiences from the last year of LHC RUN2 data taking and evolution of our services in the past year.. We will highlight upcoming changes and future improvements and challenges.

The synthesis of a sponge-like carbon aerogel from microfibril cellulose, with high porosity (99 %), ultra-low density (0.01 g/cm3), hydrophobic properties (149° static contact angle) and reusability is reported in this paper. The physical properties, internal morphology, thermal properties, and chemical properties of carbon aerogels heat-treated at 700 and 900 °C (Samples C-700 and C-900) were examined. Stabilization and carbonization parameters were optimized in terms of residual carbon yield. The BET surface area of Sample C-700 (521 m2/g) was significantly higher than of Sample C-950 (145 m2/g). Graphitic-like domains were observed in C-950. The highest normalized sorption capacity (86 g/g) for paraffin oil was observed in sample C-700. The removal of hydrophilic function groups during carbonization causes carbon aerogel to present highly hydrophobic properties. Carbon aerogel’s ability to absorb oil is enhanced by its highly porous 3D network structure with interconnected cellulose nanofibrils.