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The mid-infrared lightweight tunable diode laser hygrometer, "Pico-Light H 2 O", the successor to Pico-SDLA H 2 O, is presented and its performances are evaluated during the AsA 2022 balloon-borne intercomparison campaign conducted at the CNES Aire-sur-l'Adour (AsA, 43.70° N; 0.25° W) balloon launch facility and the Aeroclub d'Aire-sur-l'Adour in France. The Pico-Light instrument has primarily been developed for sounding of the upper troposphere and stratosphere, although during the AsA 2022 campaign we expand the range of comparison to include additionally the lower troposphere. Three different types of hygrometer and two models of radiosonde were flown, operated by the French Space Agency (CNES) and the NOAA Global Monitoring Laboratory (GML) scientific teams: Pico-Light H 2 O, the NOAA Frost Point Hygrometer (FPH), the micro-hygrometer (in an early phase of development), and M20 and iMet-4 sondes. Within this framework, we intend to validate measurements of Pico-Light H 2 O through a first intercomparison with the NOAA FPH instrument. The in situ monitoring of water vapour in the upper troposphere–lower stratosphere continues to be very challenging from an instrumental point of view because of the very small amounts of water vapour to be measured in these regions of the atmosphere. Between the lapse rate tropopause (11–12.3 km) and 20 km, the mean relative difference between water vapour mixing ratio measurements by Pico-Light H 2 O and NOAA FPH was 4.2 % ± 7.7 %, and the mean tropospheric difference was 3.84 % ± 23.64 %, with differences depending on the altitude range considered. In the troposphere, relative humidity (RH) over water comparisons led to agreement between Pico-Light and NOAA FPH of - 0.2 % on average, with excursions of about 30 % RH due to moisture variability. Expanding the comparison to meteorological sondes, the iMet-4 sondes agree well with both Pico-Light and FPH between the ground and 7.5 km (within ± 3 % RH), as do the M20 sondes, up to 13 km, which are wet-biased by 3 % RH and dry-biased by 20 % in cases of saturation. [ABSTRACT FROM AUTHOR]

The mid-infrared lightweight stratospheric hygrometer, "Pico-Light H2O", the successor of Pico-SDLA H2O, is presented and its performances are evaluated during the AsA 2022 balloon-borne intercomparison campaign conducted at CNES Aire-sur-l'Adour (AsA) balloon launch facility and the Aeroclub d'Aire-sur-l'Adour. The Pico-Light instrument primarily been developed for sounding of the upper troposphere and stratosphere. Though, during the AsA 2022 campaign we expand the range of comparison including the lower troposphere additionally. Three different types of hygrometers and two models of radiosonde were flown, operated by the French Space Agency (CNES) and the NOAA Global Monitoring Laboratory (GML) scientific teams: Pico-Light H2O, the NOAA Frost Point Hygrometer (FPH), the micro hygrometer (in an early phase of development), M20 and iMet-4 sondes. In this frame, we intend to validate measurements of Pico-Light H2O through a first intercomparison with the NOAA FPH instrument. The in situ monitoring of water vapour in the UT-LS keeps being very challenging from an instrumental point of view because of the very small amounts of water vapour to be measured in these regions of the atmosphere. Between the lapse rate tropopause (11 to 12.3 km) and 20 km, the mean relative difference between water vapour mixing ratio measurements by Pico-Light H2O and NOAA FPH was (4.2 ± 7.7) %, mean tropospheric difference is was (3.84 ± 23.64)%, with differences depending on the altitude range considered. In the troposphere, relative humidity over water (RH) comparisons leads to an agreement between both Pico-Light and NOAA FPH of -0.2% on average, with excursions of about 30% RH due to moisture variability. Expanding the comparison to meteorological sondes, the iMet-4 sondes agree well with both Pico-Light and FPH between ground and 7.5 km (within ± 3% RH) and so does for M20 sondes, up to 13 km, which are wet biased by 3% RH and dry biased by 20% in case of saturation. [ABSTRACT FROM AUTHOR]

This article presents a fast and approximate multifrontal solver for large sparse linear systems. In a recent work by Liu et al., we showed the efficiency of a multifrontal solver leveraging the butterfly algorithm and its hierarchical matrix extension, HODBF (hierarchical off-diagonal butterfly) compression to compress large frontal matrices. The resulting multifrontal solver can attain quasi-linear computation and memory complexity when applied to sparse linear systems arising from spatial discretization of high-frequency wave equations. To further reduce the overall number of operations and especially the factorization memory usage to scale to larger problem sizes, in this article we develop a composite multifrontal solver that employs the HODBF format for large-sized fronts, a reduced-memory version of the nonhierarchical block low-rank format for medium-sized fronts, and a lossy compression format for small-sized fronts. This allows us to solve sparse linear systems of dimension up to 2.7 × larger than before and leads to a memory consumption that is reduced by 70% while ensuring the same execution time. The code is made publicly available in GitHub. [ABSTRACT FROM AUTHOR]

Permeability is a key property in various fields such as membrane technology for chemical separation and transport of substances through cell membranes. At the molecular scale, the counting method uses the number of membrane crossings in a conventional unbiased molecular dynamics simulation to predict the permeability. This contribution investigates under which conditions the counting method has insufficient statistics. An equation is derived for a compartmental model based on the inhomogeneous solubility–diffusion (Smoluchowski) model, giving insight into how the flux correlates with the solubility of permeants. This equation shows that a membrane crossing is a rare event not only when the membrane forms a large free energy barrier but also when the membrane forms a deep free energy well that traps permeants. Such a permeant trap has a high permeability; yet, the counting method suffers from poor statistics. To illustrate this, coarse-grained MD was run for 16 systems of dipalmitoylphosphatidylcholine bilayer membranes with different permeant types. The composition rule for permeability is shown to also hold for fluxes, and it is highlighted that the considered thickness of the membrane causes uncertainty in the permeability calculation of highly permeable membranes. In conclusion, a high permeability in itself is not an effective indicator of the sampling efficiency of the counting method, and caution should be taken for permeants whose solubility varies greatly over the simulation box. A practical consequence relevant in, e.g., drug design is that a drug with high membrane permeability might get trapped by membranes thus reducing its efficacy. [ABSTRACT FROM AUTHOR]

Permeation of many small molecules through lipid bilayers can be directly observed in molecular dynamics simulations on the nano- and microsecond timescale. While unbiased simulations provide an unobstructed view of the permeation process, their feasibility for computing permeability coefficients depends on various factors that differ for each permeant. The present work studies three small molecules for which unbiased simulations of permeation are feasible within less than a microsecond, one hydrophobic (oxygen), one hydrophilic (water), and one amphiphilic (ethanol). Permeabilities are computed using two approaches: counting methods and a maximum-likelihood estimation for the inhomogeneous solubility diffusion (ISD) model. Counting methods yield nearly model-free estimates of the permeability for all three permeants. While the ISD-based approach is reasonable for oxygen, it lacks precision for water due to insufficient sampling and results in misleading estimates for ethanol due to invalid model assumptions. It is also demonstrated that simulations using a Langevin thermostat with collision frequencies of 1/ps and 5/ps yield oxygen permeabilities and diffusion constants that are lower than those using Nosé–Hoover by statistically significant margins. In contrast, permeabilities from trajectories generated with Nosé–Hoover and the microcanonical ensemble do not show statistically significant differences. As molecular simulations become more affordable and accurate, calculation of permeability for an expanding range of molecules will be feasible using unbiased simulations. The present work summarizes theoretical underpinnings, identifies pitfalls, and develops best practices for such simulations. [ABSTRACT FROM AUTHOR]

• Implemented K-CliqueWeight into the ProBiS-Dock algorithm, enhancing its capabilities for molecular docking. • Efficiently identifies the top N weighted k-cliques, addressing challenges in molecular docking and diverse problem domains. • Demonstrated superior performance of K-CliqueWeight, surpassing alternatives by several orders of magnitude. • Accessible to academia for free at http://insilab.org/kcliqueweight, facilitating widespread use. Molecular docking, a key process in drug discovery, is often used in the discovery of new bioactive compounds. In this technique, small molecules are systematically placed at a protein binding site to identify the ligands with the highest binding affinity. Here we have developed a new graph-theoretical algorithm called K-CliqueWeight. This algorithm efficiently identifies the top N highest weight k-cliques in different types of vertex-weighted graphs and can serve as a building block for various algorithms addressing different problems, including molecular docking. K-CliqueWeight and its variant K-CliqueDynWeight are extensions of our established and widely used maximum clique algorithm. Our new algorithm uses a novel approach to approximate graph coloring and provides efficient upper bounds on the size and weight of a k-clique within the branch-and-bound algorithm. It outperforms alternative methods and often shows a speedup of several orders of magnitude. Rigorous tests with general random graphs and those specifically designed for docking confirm its exceptional performance. K-CliqueWeight has been integrated into the existing ProBiS-Dock algorithm for molecular docking. The algorithm is freely available to the academic community at http://insilab.org/kcliqueweight. [Display omitted] [ABSTRACT FROM AUTHOR]

We present a fast and approximate multifrontal solver for large-scale sparse linear systems arising from finite-difference, finite-volume, or finite-element discretization of high-frequency wave equations. The proposed solver leverages the butterfly algorithm and its hierarchical matrix extension for compressing and factorizing large frontal matrices via graph distance guided entry evaluation or randomized matrix-vector multiplication-based schemes. Complexity analysis and numerical experiments demonstrate O (N log² N) computation and O (N) memory complexity when applied to an N X N sparse system arising from 3D high-frequency Helmholtz and Maxwell problems. [ABSTRACT FROM AUTHOR]

We present and discuss the advancements made in PyRETIS 3, the third instalment of our Python library for an efficient and user‐friendly rare event simulation, focused to execute molecular simulations with replica exchange transition interface sampling (RETIS) and its variations. Apart from a general rewiring of the internal code towards a more modular structure, several recently developed sampling strategies have been implemented. These include recently developed Monte Carlo moves to increase path decorrelation and convergence rate, and new ensemble definitions to handle the challenges of long‐lived metastable states and transitions with unbounded reactant and product states. Additionally, the post‐analysis software PyVisa is now embedded in the main code, allowing fast use of machine‐learning algorithms for clustering and visualising collective variables in the simulation data. [ABSTRACT FROM AUTHOR]

Lignin holds the potential to obtain key monoaromatic compounds upon its depolymerization. Depolymerization of woody biomass by pyrolysis is well established but often unsuccessful for lignin due to a combination of its melting, agglomeration, and modest yields towards aromatics. Therefore, several lignin additives have been put forth to overcome one or more of these hurdles. Although some seem promising, a direct comparison is obscured by differences in applied technical lignin types, reactor configurations/scales, and product analyses. Moreover, the effects of additives have either been evaluated mostly on an analytical scale or their mode of action is not entirely understood. This work involves the addition of clays, calcium hydroxide and sodium formate to lignin, each having a different (putative) mode of action, in a well-defined and comparable manner. Organosolv lignin and lignin with additives were analysed by TGA/DSC and py-GC/MS. Pyrolysis was performed in a lab-scale reactor (350 g feeding). The pyrolysis liquids were characterised through elemental analysis, GCxGC-FID, GCxGC-HR-ToF-MS, GPC, and HSQC NMR analyses. All additives overcame melting issues and led to increased liquid yields but the most promising were attapulgite and calcium hydroxide. Lignin with attapulgite resulted in a heavy phase with the highest carbon yield (25.7%) and a substantial monomer yield (18.9%, mostly alkylphenols). Lignin with calcium hydroxide resulted in a heavy phase with the highest monomer yield (23.8%, mostly alkylphenols) at a substantial carbon yield (15.1%). The pyrolysis mechanisms for lignins with additives are elaborated and updated in this work. [ABSTRACT FROM AUTHOR]

Primary objective: The objective of this study was to design an instrument to screen for burden in the daily life of both the client with acquired brain injury (ABI) and their nonprofessional caregiver. Research Design: Exploratory research Methods and Procedures: Based on a survey amongst stakeholder organizations, the FINAH-instrument is designed as a digital self-assessment questionnaire, based on ICF-framework. A test survey of the FINAH instrument is conducted on both clients, nonprofessional caregivers and healthcare professionals. Main Outcomes and Results: The relative burden per item for clients and nonprofessional caregivers is most prominent in the domains of fatigue, cognitive and emotional consequences, self-care and mobility. The estimation of burden for clients and nonprofessional caregiver by healthcare professionals showed an overall 65% correct estimation by the healthcare professional. 19% of the items showed underestimation of burden, while 16% showed overestimation. Conclusions: These results show that FINAH can ameliorate the estimation of the health care professional on the self-assessed burden of clients and nonprofessional caregivers, thus substantiating a more client-centred approach. [ABSTRACT FROM AUTHOR]

• Fast pyrolysis of mannan-rich ivory nut was performed at 350 °C and 500 °C. • Pyrolysis liquids (yield 58–60 wt%) were rich in levomannosan and 5-hydroxymethyl furfural. • Biochar and non-condensible gases (NCGs) were characterized. • Biochar holds potential for e.g. soil applications, NCGs hold potential for e.g. syngas processes. Ivory nut residues from the palm Phytelephas aequatorialis were converted via fast pyrolysis into a set of valuable biorefinery products, being (i) pyrolysis liquids rich in levomannosan and 5-hydroxymethyl furfural (5-HMF), (ii) biochar, with potential for soil applications, (iii) and non-condensable gases with potential for upgrading and syngas processes. The ivory nut residues were mannan-rich leftovers from button manufacturing in Ecuador. A handful of studies, dating back from the 20th century, have investigated gram-scale valorization of ivory nut to e.g. mannose. Nevertheless, advances in science and technology on biorefinery products called for a comprehensive reassessment of the valorization potential of this underutilized feedstock. A fully equipped, continuously operated lab-scale reactor (200 g.h−1 feed) was used for pyrolysis at 350 °C and 500 °C. The pyrolysis liquid yield was 57.53 wt% at 350 °C and 60.36 wt% at 500 °C. The aqueous phase obtained at 350 °C contained 17.5 wt% (d.b.) anhydrosugars, of which 90% was levomannosan, and contained 11.6 wt% (d.b.) furans, of which 56% was 5-HMF and 17% furfural. The carbon stability of the biochars, measured with the Edinburgh accelerated ageing tool, were 40.6% and 64.6%, respectively. Non-condensable gases during pyrolysis at 350 °C only were composed of CO 2 and CO (CO 2 :CO molar ratio of 4:1), while at 500 °C, gases were obtained with a CO 2 :CO:H 2 :CH 4 molar ratio of 9:9:4:1. Overall, the results demonstrate that pyrolysis of ivory nut holds potential as starting point for valuable biorefinery products. [ABSTRACT FROM AUTHOR]

There is a need for groundwater modelling approaches that can incorporate both the complexity of riverbeds and the influence of lateral flows through the river banks in the simulation of river–aquifer interaction. A simple and straight-forward approach is proposed for modelling river–aquifer interaction in gaining rivers based on existing building blocks available in MODFLOW. The river water itself is modelled as constant-head cells, while the riverbed is modelled as one or more separate layers. The Horizontal Flow Barrier (HFB) Package is used to simulate the effect of a river bank on lateral exchange fluxes between river and aquifer. This approach has several advantages over conventional MODFLOW streamflow packages: (1) riverbeds can be modelled as several layers with different hydraulic properties; (2) both vertical and horizontal flow through the riverbed can be modelled; and (3) lateral flow through the river banks can be simulated. The capabilities of the new approach are demonstrated in two applications based on a MODFLOW model of the Aa River, Belgium. Application I demonstrates that the approach can be used to model heterogeneous multi-layered riverbeds. Results show that neglecting this heterogeneity can result in an overestimation of river–aquifer exchange fluxes. Application II shows that the approach can be used to simulate the effect of lateral fluxes through river banks. It demonstrates that lateral fluxes can be a major contributor to total river–aquifer exchange fluxes. The proposed approach provides the necessary tools to accurately model river–aquifer interaction for gaining rivers in MODFLOW. [ABSTRACT FROM AUTHOR]

Abstract Lignin-rich digested stillage as a novel feedstock for biochar production was subjected to slow pyrolysis. The lignin residue stemmed from a lignocellulosic ethanol pilot run with poplar, from which the stillage was anaerobically digested prior to pyrolysis. Pyrolysis conditions were optimized to meet guidelines put forth by the International Biochar Initiative and the European Biochar Certificate (molar H/C org ratio < 0.7 and O/C org ratio < 0.4), as biochar could be carbon-negative upon soil amendment, while reallocating nutrients to the field. Bench-scale pyrolysis of the lignin residue and straw were conducted according to a 33 factorial design with center runs (ranges: 370–450 °C highest treatment temperature, 5–45 min holding time and 5–50 °C.min−1 heating rate). Parametric and nonparametric statistics revealed that the highest treatment temperature was by far the most influencing factor for both feedstocks which 'pushed' H/C and O/C ratios within the desired range. Lignin-based biochar can be obtained with 50.7% yield, a H/C ratio of 0.70 and an O/C ratio of 0.20, already at 384 °C. This is considerably better when compared to straw-based biochar with identical H/C and O/C ratios, which came with a lower yield (33.7%) and required a modestly higher temperature (410 °C). Results from this study emphasize the feasibility to integrate slow pyrolysis in a lignocellulosic biorefinery. Graphical abstract Image 1 Highlights • Lignin residue from digested stillage was pyrolysed to biochar for the first time. • Temperature, heating rate and holding time were varied in a 33 factorial design. • Statistical models were used for process optimization to meet biochar standards. • The quality-quantity trade-off during pyrolysis was assessed. • At 384 °C, lignin-biochar with H/C = 0.7 and O/C = 0.2 is obtained with 50.71% yield. [ABSTRACT FROM AUTHOR]

The spatial distribution of hydraulic conductivity (K) in riverbeds is essential to understand and model river-groundwater interactions. However, K in riverbeds varies over several orders of magnitude and its spatial distribution is closely linked to complex geological and fluvial processes. Investigating the local distribution and spatial heterogeneity of K is therefore a challenging task. The use of direct current (DC) and time-domain-induced polarization (IP) geoelectrical methods to map qualitatively the spatial distribution of K within riverbeds is described. The approach is demonstrated for a test site situated in a typical lowland river in Belgium. Inverted geophysical parameters (resistivity, chargeability and normalized chargeability) are compared with estimates of K obtained through slug tests. In general, high values of K are observed in the middle of the river and lower values towards the banks, while the opposite is true for chargeability and normalized chargeability. Therefore, there exists an inverse correlation between K and IP geophysical parameters. Furthermore, geostatistical analyses using variograms show that all parameters have ranges of similar magnitudes. The strong correlation between K and chargeability or normalized chargeability can be explained by the fact that all three parameters are mainly controlled by clay and organic matter content. [ABSTRACT FROM AUTHOR]

The absorption spectrum of 13 CH 4 is recorded in the center of the tetradecad near 1.73 μm (5695–5850 cm −1 ) at 296 K and 80 K by direct absorption spectroscopy (DAS). The achieved noise equivalent absorption of the spectra is α min  ≈ 5 × 10 −8  cm −1 leading to line intensity detectivity threshold on the order of 5 × 10 −26 and 5 × 10 −27  cm/molecule at 296 K and 80 K, respectively. As a result, two empirical line lists are constructed including about 3350 and 2070 lines at room temperature and liquid nitrogen temperature, respectively. For comparison, the HITRAN database provides in the region only the strongest 13 CH 4 lines (about 440 lines in total). From the intensity ratios of the lines measured at the two temperatures, 1529 empirical values of the lower state energy level ( E emp ) were derived. Their accuracy is reflected by the clear propensity of the corresponding empirical values of the lower state rotational quantum number, J emp , to be close to integer values. They provide accurate temperature dependence for 91% and 99% of the total 13 CH 4 absorption in the region at 296 K and 80 K, respectively. The comparison to the TheoReTS ab initio line list shows significant deviations for line positions. The obtained experimental data will be valuable to tune ab initio line positions to empirical values in future versions of the theoretical line lists. [ABSTRACT FROM AUTHOR]

A tubular furnace is combined with a diode laser spectrometer to record the high temperature near infrared absorption spectrum of methane at a pressure of 80 Torr. The investigated spectral range covers the 5693–6257 cm −1 (1.75–1.60 µm) range of the tetradecad dominated by the 2ν 3 band near 6000 cm −1 . Various determinations (thermocouples, Doppler line broadening, rotational temperature) provide a value of about 964 K for the gas temperature. Lines with intensity larger than 5 × 10 −24  cm/molecule at 1000 K are detected. As a result of the high temperature, high- J rovibrational transitions up to J  ≈ 20 and hot bands are identified in the spectrum. The recorded spectra provide tests of various methane line lists recently released in the literature: HITRAN2016, experimental list derived from emission spectra, the MeCaSDa empirical line list and the TheoReTs and ExoMol theoretical line lists. The agreement with the TheoReTs line list is found to be very good in the studied region. [ABSTRACT FROM AUTHOR]

Abstract: This paper provides new evidence on the effect of computerized individualized practice and instruction on language skills, more specifically on spelling. An individually randomized experiment among 7th grade students in the Netherlands is developed to study the effect of an adaptive digital homework tool on spelling performance. Using an instrumental variable approach to control for actual use of the digital tool, we show that there are small positive effects of practicing with an adaptive digital tool for spelling for 7th grade students. Effects are largest for low‐performing students. [ABSTRACT FROM AUTHOR]

The methane absorption spectrum is studied at 297 K and 80 K in the center of the Tetradecad between 5695 and 5850 cm −1 . The spectra are recorded by differential absorption spectroscopy (DAS) with a noise equivalent absorption of about α min   ≈ 1.5 × 10 −7 cm −1 . Two empirical line lists are constructed including about 4000 and 2300 lines at 297 K and 80 K, respectively. Lines due to 13 CH 4 present in natural abundance were identified by comparison with a spectrum of pure 13 CH 4 recorded in the same temperature conditions. About 1700 empirical values of the lower state energy level, E emp , were derived from the ratios of the line intensities at 80 K and 296 K. They provide accurate temperature dependence for most of the absorption in the region (93% and 82% at 80 K and 296 K, respectively). The quality of the derived empirical values is illustrated by the clear propensity of the corresponding lower state rotational quantum number, J emp , to be close to integer values. Using an effective Hamiltonian model derived from a previously published ab initio potential energy surface, about 2060 lines are rovibrationnally assigned, adding about 1660 new assignments to those provided in the HITRAN database for 12 CH 4 in the region. [ABSTRACT FROM AUTHOR]

An improved general understanding of riverbed heterogeneity is of importance for all groundwater modeling studies that include river-aquifer interaction processes. Riverbed hydraulic conductivity ( K ) is one of the main factors controlling river-aquifer exchange fluxes. However, the meter-scale spatial variability of riverbed K has not been adequately mapped as of yet. This study aims to fill this void by combining an extensive field measurement campaign focusing on both horizontal and vertical riverbed K with a detailed geostatistical analysis of the meter-scale spatial variability of riverbed K . In total, 220 slug tests and 45 standpipe tests were performed at two test sites along the Belgian Aa River. Omnidirectional and directional variograms (along and across the river) were calculated. Both horizontal and vertical riverbed K vary over several orders of magnitude and show significant meter-scale spatial variation. Horizontal K shows a bimodal distribution. Elongated zones of high horizontal K along the river course are observed at both sections, indicating a link between riverbed structures, depositional environment and flow regime. Vertical K is lognormally distributed and its spatial variability is mainly governed by the presence and thickness of a low permeable organic layer at the top of the riverbed. The absence of this layer in the center of the river leads to high vertical K and is related to scouring of the riverbed by high discharge events. Variograms of both horizontal and vertical K show a clear directional anisotropy with ranges along the river being twice as large as those across the river. [ABSTRACT FROM AUTHOR]

A microbial production process was developed to convert CO 2 and valeric acid into tailored poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) bioplastics. The aim was to understand microbial PHBV production in mixotrophic conditions and to control the monomer distribution in the polymer. Continuous sparging of CO 2 with pulse and pH-stat feeding of valeric acid were evaluated to produce PHBV copolyesters with predefined properties. The desired random monomer distribution was obtained by limiting the valeric acid concentration (below 1  g L - 1 ). 1 H-NMR, 13 C-NMR and chromatographic analysis of the PHBV copolymer confirmed both the monomer distribution and the 3-hydroxyvalerate (3HV) fraction in the produced PHBV. A physical-based model was developed for mixotrophic PHBV production, which was calibrated and validated with independent experimental datasets. To produce PHBV with a predefined 3HV fraction, an operating diagram was constructed. This tool was able to predict the 3HV fraction with a very good accuracy (2% deviation). [ABSTRACT FROM AUTHOR]

This paper analyses an experiment on the effect of an individualized, digital practice tool on numeracy skills for 337 seventh grade students. The first stage of the experiment shows that offering students the opportunity to practice numeracy digitally at home (intent-to-treat) leads to a substantial and significant increase in numeracy performance growth. The second stage reveals that the effectiveness of the tool mainly stems from its individualized nature. With good implementation prospects and relatively low costs, the consequences are discussed to be potentially large. [ABSTRACT FROM AUTHOR]

We present a new cavity ring-down spectroscopy system which was developed for variable-temperature absorption measurements (220-290 K) of atmospheric gases. This laser spectrometer was developed in the framework of the NASA Orbiting Carbon Observatory-2 project to improve our understanding of line shape parameters for carbon dioxide and oxygen. The apparatus consists of a monolithic, fixed-mirror ring-down cavity within a temperature-regulated enclosure, which is interrogated by a tunable, single-frequency diode laser. We experimentally characterize and model the dependence of the spectrum detuning axis at each setpoint temperature, and show that absolute frequencies are stable to within 200 kHz over several hours, corresponding to temperature stabilities better than 1 mK. We measure the R16e (30013-0001) CO transition and carry out multi-spectrum analyses using two line profiles incorporating speed-dependent (quadratic approximation) and Dicke narrowing (hard collision assumption) effects. The resulting broadening coefficient and temperature exponent are in excellent agreement (0.05% level) with previous high-resolution Fourier-transform spectroscopy measurements, and the speed dependent broadening parameter is within 3% of the theoretical value. [ABSTRACT FROM AUTHOR]

Background: In order to enhance occupational therapy reasoning in clinical practice, different elements such as client-centred approach, evidence-based care and interdisciplinary work should be taken into account, but is a challenge. Aim: To describe the development of the digital Hasselt Occupational Performance Profile (H-OPP©) that enhances occupational therapy reasoning from ICF perspective. Method: A participative qualitative design was used to create the H-OPP© in an iterative way in which occupational therapy lectures, ICF experts, students and occupational therapists in the field were involved. Results: After linking occupational therapy terminology to the ICF, different stages of the H-OPP were identified and elaborated with main features: generating an occupational performance profile based on inventarization of problems and possibilities, formulating an occupational performance diagnosis and enabling to create an intervention plan. In all stages, both the perspectives of the client and the occupational therapist were taken into account. To increase practical use, the tool was further elaborated and digitalized. Conclusion: The H-OPP© is a digital coach that guides and facilitates professional reasoning in (novice) occupational therapists. It augments involvement of the client system. Furthermore, it enhances interdisciplinary communication and evidence-based care. [ABSTRACT FROM AUTHOR]

This study uses time-diary data for dual-earner couples from Belgium, Denmark, Spain, and the United Kingdom to analyze educational inequalities in parental care time in different national contexts. For mothers, education is significantly associated with parenting involvement only in Spain and the United Kingdom. In Spain these differences are largely explained by inequalities in mothers' time and monetary resources, but not in the United Kingdom, where less-educated mothers disproportionally work in short part-time jobs. For fathers, education is associated with parenting time in Denmark, and particularly in Spain, while the wife's resources substantially drive these associations. On weekends, the educational gradient in parental care time applies only to Spain and the United Kingdom, two countries with particularly large inequalities in parents' opportunities to engage in parenting. The study shows country variations in educational inequalities in parenting, suggesting that socioeconomic resources, especially from mothers, shape important variations in parenting involvement. [ABSTRACT FROM AUTHOR]

This work pioneers the thermocatalytic conversion of tagua seeds (or ivory nut) from the palm Phytelephas aequatorialis into key chemical building blocks, being levoglucosenone, furfural and levomannosan. Annually, ca. 100,000 metric ton of those seeds are produced in Ecuador. Mannan (a mannose-polymer similar to cellulose) is the main constituent in tagua. Thermocatalytic conversions were first explored on analytical scale to see if – and to which extent – e.g., levoglucosenone, was obtained from tagua, using catalysts with proven activity for cellulose conversion, being H3PO4 or ZnCl2. Non-catalytic fast pyrolysis led to levomannosan as main product (33.89 wt% ± 0.24 wt%), much like levoglucosan is the main product from cellulose pyrolysis. Catalytic fast pyrolysis using H3PO4 or ZnCl2 resulted in value-added levoglucosenone (max 6.64 wt% ± 0.27 wt%) and furfural (max 13.17 wt% ± 0.66 wt%) at the expense of levomannosan (between 12 wt.%–14 wt%). Validation experiments with a continuous fast pyrolysis auger reactor were successful and led to pyrolysis liquids with e.g., 3.69 wt% levoglucosenone, using H3PO4 -infused ivory nut. Although further optimization should follow this work, the results showcased a fundamental "mannan to levoglucosenone and furfural" conversion and therefore the potential of mannan-rich feedstock for biorefining. Moreover, these results can be translated to other mannan-rich agricultural residues, like açaí seeds, which are a major residue in Brazil (1.1 million metric ton annually). [Display omitted] • Mannan-rich tagua was demonstrated a valuable biorefinery feedstock. • Tagua was converted to levoglucosenone and furfural with H 3 PO 4 and ZnCl 2 , resp. • Analytical experiments were successfully translated to mini-plant scale experiments. • The biorefinery potential of mannan-rich ivory nut has been showcased. [ABSTRACT FROM AUTHOR]

Childcare services are increasingly regarded a major policy lever to combat social inequalities in early life. Yet, it was shown that inequality in the use of childcare services is the norm rather than the exception in European and Organisation for Economic Co-operation and Development (OECD) countries. As a result, social inequalities between disadvantaged and advantaged children are likely to be reinforced instead of being narrowed. The aim of this article is to conduct a macro-level analysis exploring which welfare state characteristics are associated with inequality in childcare use. We find that government involvement in the availability, affordability and quality of service provision is related to lower levels of inequality in childcare use. The results also suggest an impact of labour market opportunities and parental leave schemes. The findings contribute to a proper understanding of the institutional mechanisms underlying inequality in childcare service use. [ABSTRACT FROM AUTHOR]

We present a sparse linear system solver that is based on a multifrontal variant of Gaussian elimination and exploits low-rank approximation of the resulting dense frontal matrices. We use hierarchically semiseparable (HSS) matrices, which have low-rank off-diagonal blocks, to approximate the frontal matrices. For HSS matrix construction, a randomized sampling algorithm is used together with interpolative decompositions. The combination of the randomized compression with a fast ULV HSS factorization leads to a solver with lower computational complexity than the standard multifrontal method for many applications, resulting in speedups up to sevenfold for problems in our test suite. The implementation targets many-core systems by using task parallelism with dynamic runtime scheduling. Numerical experiments show performance improvements over state-ofthe-art sparse direct solvers. The implementation achieves high performance and good scalability on a range of modern shared memory parallel systems, including the Intel Xeon Phi (MIC). The code is part of a software package called STRUMPACK (STRUctured Matrices PACKage), which also has a distributed memory component for dense rank-structured matrices. [ABSTRACT FROM AUTHOR]

In this paper we compare water vapor mixing ratio measurements from two quasi-parallel flights of the Pico-SDLA H2O and FLASH-B hygrometers. The measurements were made on 10 February 2013 and 13 March 2012, respectively, in the tropics near Bauru, São Paulo state, Brazil during an intense convective period. Both flights were performed as part of a French scientific project, TRO-Pico, to study the impact of the deep-convection overshoot on the water budget. Only a few instruments that permit the frequent sounding of stratospheric water vapor can be flown within smallvolume weather balloons. Technical difficulties preclude the accurate measurement of stratospheric water vapor with conventional in situ techniques. The instruments described here are simple and lightweight, which permits their low-cost deployment by non-specialists aboard a small weather balloon. We obtain mixing ratio retrievals which agree above the coldpoint tropopause to within 1.9 and 0.5% for the first and second flights, respectively. This level of agreement for balloonborne measured stratospheric water mixing ratio constitutes one of the best agreement reported in the literature. Because both instruments show similar profiles within their combined uncertainties, we conclude that the Pico-SDLA H2O and FLASH-B data sets are mutually consistent. [ABSTRACT FROM AUTHOR]

In this paper we compare water vapor mixing ratio measurements from two quasi-parallel flights of the Pico-SDLA H2O and FLASH-B hygrometers. The measurements were made on 10 February 2013 and 13 March 2012, respectively, in the tropics near Bauru, São Paulo state, Brazil during an intense convective period. Both flights were performed as part of a French scientific project, TRO-Pico, to study the impact of the deep-convection overshoot on the water budget. Only a few instruments that permit the frequent sounding of stratospheric water vapor can be flown within small-volume weather balloons. Technical difficulties preclude the accurate measurement of stratospheric water vapor with conventional in situ techniques. The instruments described here are simple and lightweight, which permits their low-cost deployment by non-specialists aboard a small weather balloon. We obtain mixing ratio retrievals which agree above the cold-point tropopause to within 1.9 and 0.5 % for the first and second flights, respectively. This level of agreement for balloon-borne measured stratospheric water mixing ratio constitutes one of the best agreement reported in the literature. Because both instruments show similar profiles within their combined uncertainties, we conclude that the Pico-SDLA H2O and FLASH-B data sets are mutually consistent. [ABSTRACT FROM AUTHOR]

This article examines an educational experiment with a unique combination of 3 elements: homework, the use of information and communication technology and a large degree of freedom of choice (student autonomy). More particularly, we study the effectiveness of a web-based intelligent tutoring system (ITS) that a school offers to its students as optional homework, in a sample of 355 first-year secondary students, using an experimental design. The results show that whether students make this noncompulsory homework in the web-based ITS is dependent on their prior achievement and their teacher, and if they practice, they tend to choose easier modules. Students thus do not seem to optimize learning gains, but rather balance their perceived value of practicing and their "expectancy," as found previously for regular (compulsory, non-ITS) homework. Regarding the value of choice, findings suggest that students may be poor judges of their most beneficial exercises pattern. Differentiation in ITS does not guarantee learning, unless scaffolding is tightly linked to it. In line with previous research, this research shows that practice does matter, though at varying intensities. Yet it also clarifies that motivation to make an effort is required, which adds to the lessons learned from homework research; both the perceived value and expectancy are at play and can be enhanced, for example, by teachers. [ABSTRACT FROM AUTHOR]

A new semi-analytical mean-field model is proposed to rationalise breathing of MIL-53 type materials. The model is applied on two case studies, the guest-induced breathing of MIL-53(Cr) with CO2and CH4, and the phase transformations for MIL-53(Al) upon xenon adsorption. Experimentally, MIL-53(Cr) breathes upon CO2adsorption, which was not observed for CH4. This result could be ascribed to the stronger interaction of carbon dioxide with the host matrix. For MIL-53(Al) a phase transition from the large pore phase could be enforced to an intermediate phase with volumes of about 1160–1300 Å3, which corresponds well to the phase observed experimentally upon xenon adsorption. Our thermodynamic model correlates nicely with the adsorption pressure model proposed by Coudert et al. Furthermore the model can predict breathing behaviour of other flexible materials, if the user can determine the free energy of the empty host, the interaction energy between a guest molecule and the host matrix and the pore volume accessible to the guest molecules. This will allow to generate the osmotic potential from which the equilibria can be deduced and the anticipated experimentally observed phase may be predicted. [ABSTRACT FROM AUTHOR]

We examine the effects of mixed sampling frequencies and temporal aggregation on the size of commonly used tests for cointegration, and we find that these effects may be severe. Matching sampling schemes of all series generally reduces size distortion, and the nominal size is obtained asymptotically only when all series are skip sampled in the same way - for example, end-of-period sampling. We propose and analyse mixed-frequency versions of the cointegration tests in order to control the size when some high-frequency data are available. Otherwise, when no high-frequency data are available, we discuss controlling size using bootstrapped critical values. We test stock prices and dividends for cointegration as an empirical demonstration. [ABSTRACT FROM AUTHOR]

This paper explores the effect of digital differentiation on student performance using a randomized experiment. The experiment is conducted in a second year biology class among 115 prevocational students in the Netherlands. Differentiation allowed students in the treatment group to work at three different levels. The results show that there is a significant effect of digital differentiation on the posttest score. This effect is robust to adding covariates such as students' ability, grade repetition, age, gender, class and average neighborhood income. There are no differential effects when dividing students in three groups, by ability. The results imply that differentiation in large classrooms is possible and beneficial for all students, once done digitally. [ABSTRACT FROM AUTHOR]

Community schools are becoming increasingly popular. They aim to enhance children’s educational performance by offering extended educational and social services. As community schools mainly focus on disadvantaged children, this study evaluates the effects of community schooling on the educational outcomes of these pupils. We focus on care pupils and pupils whose parents have a low educational attainment. We hypothesize that community schools are particularly beneficial to care pupils, namely, pupils with additional educational needs, and for pupils with parents with lower levels of educational attainment. Our analyses show that both pupil groups benefit in terms of reduced underachievement. The duration of community school attendance as such does not affect cognitive outcomes, but it proves beneficial to the educational achievement of both groups when the community school subsidy is taken into account as well. We show that different community school activities have partly contrary effects on care pupils and non-care pupils. [ABSTRACT FROM PUBLISHER]

This paper describes a dataset with data from three individually randomized educational technology experiments on differentiation, formative testing and feedback during one school year for a group of 8th grade students in the Netherlands, using administrative data and the online motivation questionnaire of Boekaerts. The dataset consists of pre- and posttest scores for each experiment, as well as background information on the students, such as gender, age, ability, grade repetition and neighborhood characteristics. It also includes motivation of students. The dataset, or parts of it, could be interesting to use in future studies, focusing on effects of the use of educational technology, for comparison with similar and/or slightly different experiments, and for studies such as meta-analyses or replication studies, especially given the individual experimental setup. [ABSTRACT FROM AUTHOR]

Classical iterative methods for tomographic reconstruction include the class of Algebraic Reconstruction Techniques (ART). Convergence of these stationary linear iterative methods is however notably slow. In this paper we propose the use of Krylov solvers for tomographic linear inversion problems. These advanced iterative methods feature fast convergence at the expense of a higher computational cost per iteration, causing them to be generally uncompetitive without the inclusion of a suitable preconditioner. Combining elements from standard multigrid (MG) solvers and the theory of wavelets, a novel wavelet-based multi-level (WMG) preconditioner is introduced, which is shown to significantly speed-up Krylov convergence. The performance of the WMG-preconditioned Krylov method is analyzed through a spectral analysis, and the approach is compared to existing methods like the classical Simultaneous Iterative Reconstruction Technique (SIRT) and unpreconditioned Krylov methods on a 2D tomographic benchmark problem. Numerical experiments are promising, showing the method to be competitive with the classical Algebraic Reconstruction Techniques in terms of convergence speed and overall performance (CPU time) as well as precision of the reconstruction. [ABSTRACT FROM AUTHOR]

We have ported the numerical factorization and triangular solve phases of the sparse direct solver STRUMPACK to GPU. STRUMPACK implements sparse LU factorization using the multifrontal algorithm, which performs most of its operations in dense linear algebra operations on so-called frontal matrices of various sizes. Our GPU implementation off-loads these dense linear algebra operations, as well as the sparse scatter–gather operations between frontal matrices. For the larger frontal matrices, our GPU implementation relies on vendor libraries such as cuBLAS and cuSOLVER for NVIDIA GPUs and rocBLAS and rocSOLVER for AMD GPUs. For the smaller frontal matrices we developed custom CUDA and HIP kernels to reduce kernel launch overhead. Overall, high performance is achieved by identifying submatrix factorizations corresponding to sub-trees of the multifrontal assembly tree which fit entirely in GPU memory. The multi-GPU setting uses SLATE (Software for Linear Algebra Targeting Exascale) as a modern GPU-aware replacement for ScaLAPACK. On 4 nodes of SUMMIT the code runs ∼ 10 × faster when using all 24 V100 GPUs compared to when it only uses the 168 POWER9 cores. On 8 SUMMIT nodes, using 48 V100 GPUs, the sparse solver reaches over 50TFlop/s. Compared to SuperLU, on a single V100, for a set of 17 matrices our implementation is faster for all but one matrix, and is on average 5 × (median 4 ×) faster • Ported the numerical factorization and triangular solve phases of the sparse direct multifrontal solver STRUMPACK to GPU. • GPU off-loading of dense linear algebra operations, as well as the sparse scatter–gather operations between frontal matrices. • Relying on vendor libraries such as cuBLAS and cuSOLVER for Nvidia GPUs and rocBLAS and rocSOLVER for AMD GPUs. • Multi-GPU setting uses SLATE (Software for Linear Algebra Targeting Exascale) as a modern GPU-aware replacement for ScaLAPACK. • On 4 nodes of SUMMIT the code runs ∼ 10 × faster when using all 24 V100 GPUs compared to when it only uses the 168 POWER9 cores. On 8 SUMMIT nodes, using 48 V100 GPUs, the sparse solver reaches over 50TFlop/s. Compared to SuperLU, on a single V100, for a set of 17 matrices our implementation is faster for all but one matrix, and is on average 5x faster. [ABSTRACT FROM AUTHOR]

Single mothers are vulnerable to living in poverty. The question of how to safeguard the economic status of single mothers in a context of increasing dual earnership is a crucial one. In the present study we addressed this issue by investigating the impact of child benefits on the poverty risk of single mothers in 15 European countries. We focused in particular on the design of child benefits and investigated whether targeting towards single mothers was associated with better poverty reduction. In doing so, we combined information on statutory child benefit entitlement with an empirical analysis of poverty reduction using survey data. We found that: (i) both spending effort and targeting are important to explain the effectiveness of child benefits in reducing single mother poverty; (ii) targeting is related to higher levels of poverty reduction independent of spending effort; yet (iii) it matters how targeting is done. [ABSTRACT FROM AUTHOR]

The basic building blocks of the classic geometric multigrid algorithm all have a low ratio of executed floating point operations per byte fetched from memory. On modern computer architectures, such computational kernels are typically bound by memory traffic and achieve only a small percentage of the theoretical peak floating point performance of the underlying hardware. We suggest the use of state-of-the-art (stencil) compiler techniques to improve the flop per byte ratio, also called the arithmetic intensity, of the steps in the algorithm. Our focus will be on the smoother which is a repeated stencil application. With a tiling approach based on the polyhedral loop optimization framework, data reuse in the smoother can be improved, leading to a higher effective arithmetic intensity. For an academic constant coefficient Poisson problem, we present a performance model for the multigrid V-cycle solver based on the tiled smoother. For increasing numbers of smoothing steps, there is a trade-off between the improved efficiency due to better data reuse and the additional flops required for extra smoothing steps. Our performance model predicts time to solution by linking convergence rate to arithmetic intensity via the roofline model. We show results for two-dimensional (2D) and three-dimensional (3D) simulations on Intel Sandy Bridge and for 2D simulations on Intel Xeon Phi architectures. The actual performance is compared with the theoretical predictions. [ABSTRACT FROM AUTHOR]

Highlights: [•] The manuscript presents a highly scalable preconditioned Conjugate Gradient method. [•] It presents a pipelined preconditioned Conjugate Residual method. [•] It shows how global communication can be overlapped with local work. [•] It shows numerical stability of the methods. [•] It shows improved scalability and runtime compared to CG and CR. [ABSTRACT FROM AUTHOR]

• Acid leaching breaks down the chemical structure of carbohydrates and proteins. • Pretreatment effects on pyrolysis volatiles have been discussed. • Removal of inorganics increased the relative yields in aromatics and aliphatics. • Influence of water-soluble and acid-soluble AAEM species was discussed. • Interactions between microalgae components and AAEMs catalysis were elucidated. This study compared the volatiles distribution in analytical scale pyrolysis (py-GC–MS) of Nannochloropsis gaditana (marine microalgae) and Scenedesmus almeriensis (freshwater microalgae) and their demineralized counterparts. The role of inorganic elements and their removal via ultrasonic treatment, water washing and (in)organic acid leaching were elucidated. Principal component analysis (PCA) and grey relational analysis were applied to analyze the pyrolysis volatiles distribution and demonstrate the influence of inorganic elements in pyrolysis, respectively. Demineralization affects (breaks down) the chemical structure of carbohydrates, followed by (to a lesser extent) proteins and lipids. Acid leaching promoted hydrolysis and suppressed the catalytic effect associated to inorganic elements in subsequent pyrolysis, compared to ultrasonic treatment and water washing. Elements like K and Na had a larger catalytic influence on microalgae pyrolysis than Ca and Mg. The composition and pyrolytic formation mechanism of major product groups at 500 °C were studied, including anhydrosugars, phenolics, furans, carboxylic acids, alcohols, aliphatic hydrocarbons, aromatic hydrocarbons, N-heterocyclic compounds, nitriles and amides. The results indicate that demineralization shows positive effects on fast pyrolysis of microalgae: (1) by disrupting the cell wall and releasing the lipids and cellular contents. Based on the py-GC–MS peak area normalized to sample mass, the relative contribution of hydrocarbons in the pyrolysis vapors increased from 25.5 % (NG: Nannochloropsis gaditana) to 32.1 % (NG-HCl: Nannochloropsis gaditana, HCl treated), and from 16.1 % (SA: Scenedesmus almeriensis) to 22.4 % (SA-HCl: Scenedesmus almeriensis, HCl treated); (2) by decreasing the relative yields in O-containing compounds resulting from the suppressed catalytic effects of alkali and alkaline earth metals (53.3 % (NG) to 37.1 % (NG-HCl), 57.5 % (SA) to 47.8 % (SA-HCl)) that would otherwise have been present in non-demineralized microalgae feedstock. The effects of demineralization on the denitrogenation of pyrolysis vapors were not that obvious. Suggestions for potential full scale applications have been proposed. [ABSTRACT FROM AUTHOR]

The long-term stability of biochar in soil is key for carbon capture and storage and soil amelioration. Yet, its assessment is hampered by the long time-horizons needed to actually probe biochar's stability. Therefore, quick and reliable estimation methods are sought. Analytical pyrolysis (Py-GC-MS) offers a quick tool to predict biochar's stability in soil, if adequate and validated metrics can be extracted from it. This work derives and validates stability scores from biochar pyrograms and advanced data analysis. The stability scores were benchmarked by comparison with other stability metrics (Edinburgh stability tool, fixed carbon content and atomic H/C ratio). Calibration of the stability scores with these stability metrics had an R 2 between 0.61 and 0.95; validation resulted in R 2 between 0.59 and 0.72. Overall, this work illustrates how Py-GC-MS can lead to simple and adequate predictors of biochar stability. [Display omitted] • Stability Scores derived from Py-GC-MS can probe the stability of biochar in soil. • Py-GC-MS and principal component analysis were combined to set up Stability Scores. • Stability scores were selected by comparison alternative stability metrics. • Stability scores were calibrated with max R2 of 0.95. • Stability scores were validated with max R2 of 0.72. [ABSTRACT FROM AUTHOR]

• Ethanol and acetic acid from syngas were converted into caproic acid by C. kluyveri. • Biochar (BC) and activated carbon (AC) foster bioproduction by C. kluyveri. • Differences between BC and AC translated into different fermentation profiles. • Biochar resulted in a higher initial production rate of caproic acid. • Activated carbon reduced pH-induced toxicity by partial adsorption of caproic acid. Syngas from biomass or steel mills can be fermented into a dilute stream of ethanol and acetic acid, which requires energy intensive distillation for product recovery. This can be circumvented by selective secondary fermentation of the syngas fermentation effluent to caproic acid as easier recoverable platform chemical with Clostridium kluyveri. Here, we explore the impact of biochar and activated carbon on this process. Changes during the fermentation with biochar or activated carbon were monitored, different doses were tested and the recyclability of biochar and activated carbon was assessed. Biochar decreased the lag phase and increased the caproic acid production rate (up to 0.50 g · L - 1 · h - 1 ). Upon recycling for subsequent fermentation, biochar retained this property largely. Activated carbon addition, especially at high dose, could potentially increase the conversion and selectivity towards caproic acid to 14.15 g · L - 1 (control: 11.01 g · L - 1 ) and 92% (control: 84%), respectively. [ABSTRACT FROM AUTHOR]

This work presents a continuous set-up for SCWO, which was operated at mild conditions (380 °C, 25 MPa, oxidant equivalence ratio of 2.0 and residence time of 26 s) to oxidize cellulose, lignin, and acetic acid as model compounds. The aim was to oxidize different organics consecutively to near completion in the same mild reaction conditions and set-up. These conditions can overcome some drawbacks associated to SCWO. To combine near complete oxidation with the applied mild process conditions, aqueous effluent from SCWO, containing intermediates from incomplete oxidation, was recycled for consecutive oxidation. Meanwhile, fresh feedstock was continuously fed to retain the process capacity. Upon recycling the aqueous effluent three to four times, depending on the feedstock, the oxidation efficiency increased from 63.9%, 45.3% and 28.3% in a single pass for cellulose, lignin, and acetic acid, respectively, to near 100%. The principle of effluent recirculation should allow a compact set-up to perform almost complete oxidation of different organics at mild conditions. The principles and effects of effluent recirculation are outlined, as well as practical consequences and perspectives of this novel principle to SCWO. • Supercritical water oxidation (SCWO) was performed at mild conditions. • Effluent recirculation was applied to improve organic oxidation efficiency. • The oxidizing capacity and oxygen consumption were favorable for recirculation. • A single and small setup at constant conditions oxidized different organics. [ABSTRACT FROM AUTHOR]

[Display omitted] • A green and effective strategy for biomass valorization was proposed. • Citric acid (CA) washing promoted furfural production during the torrefaction step. • CA washing increased levoglucosan yield to 3.76 times for W250-FP compared to R250-FP. • Torrefaction reduced acetic acid yield by 65% for W250-FP compared to WRaw-FP. Converting agricultural waste biomass into value-added chemicals is attractive. However, a low selectivity for target chemicals hinders practical applications. This study presents a stepwise strategy to convert sugarcane trash (ST) into furfural and levoglucosan with high selectivity. The approach includes citric acid washing to reduce mineral content in ST, followed by torrefaction at different temperatures (210 °C, 250 °C and 290 °C) in a tube furnace and then fast pyrolysis at 500 °C in a micro-reactor. This study highlights the valorization potential of the torrefaction liquid, an often overlooked by-product from torrefaction, through significantly increasing furfural selectivity during the torrefaction of washed ST. Furthermore, the vapors from subsequent fast pyrolysis of washed-torrefied ST exhibited reduced acetic acid content compared to that of solely washed ST, which is advantageous for minimizing the acidity of the resulting bio-oil. Moreover, fast pyrolysis of ST, treated with washing and torrefaction at 250 °C, achieved a high levoglucosan yield while maintaining a high furfural yield obtained in the prior torrefaction step. The findings of this study provide valuable insights into future research and industrial applications in agricultural waste biomass utilization. [ABSTRACT FROM AUTHOR]

2-methyl furan (MF) is a fuel additive with improved fuel characteristics compared to bio-ethanol. Unfortunately, the production of MF (from furfural (FF) hydrogenation) is not economically feasible. Interestingly, molten salts in biomass pyrolysis have shown to promote the formation of furans (mainly FF). Because molten salts hydropyrolysis could be an alternative route to both produce FF and convert it into MF, an assessment is indispensable. Molten salts pyrolysis and hydropyrolysis of pinewood and wheat straw and related model compounds were studied in a micro-reactor. The effect of hydropyrolysis process variables was assessed on the total detectable condensable vapors and MF formation. At low pressures (0.4 MPa), the chloride salts favored the production of FF and acetic regardless of the reaction atmosphere. Under a high pressure of hydrogen though (1.6 and 3.0 MPa), the conversion of FF to MF was enhanced through hydrogenation, hydrodeoxygenation and demethylation reactions. Molten salts hydropyrolysis at 350 °C and pressures of either 1.6 MPa (biomass mass fraction of 0.09) or 3.0 MPa (biomass mass fraction of 0.24) were optimal and yielded ca. 8 wt% to 9 wt% MF. Reaction temperatures >350 °C were unfavorable for the MF yield and instead promoted furfural decarbonylation to furan. [Display omitted] • Hydropyrolysis in molten salts highly promoted 2-methyl furan formation. • Targeted production of 2-methyl furan as fuel additive. • Higher pressure and biomass mass fraction are beneficial to product yield. • Product portfolio and yield in molten salts pyrolysis is carrier gas dependent. [ABSTRACT FROM AUTHOR]

We present new algorithms for randomized construction of hierarchically semiseparable (HSS) matrices, addressing several practical issues. The HSS construction algorithms use a partially matrix-free, adaptive randomized projection scheme to determine the maximum off-diagonal block rank. We develop both relative and absolute stopping criteria to determine the minimum dimension of the random projection matrix that is sufficient for desired accuracy. Two strategies are discussed to adaptively enlarge the random sample matrix: repeated doubling of the number of random vectors and iteratively incrementing the number of random vectors by a fixed number. The relative and absolute stopping criteria are based on probabilistic bounds for the Frobenius norm of the random projection of the Hankel blocks of the input matrix. We discuss parallel implementation and computation and communication cost of both variants. Parallel numerical results for a range of applications, including boundary element method matrices and quantum chemistry Toeplitz matrices, show the effectiveness, scalability, and numerical robustness of the proposed algorithms. [ABSTRACT FROM AUTHOR]

The volume penalization (VP) or the Brinkman penalization (BP) method is a diffuse interface method for simulating multiphase fluid-structure interaction (FSI) problems in ocean engineering and/or phase change problems in thermal sciences and engineering. The method relies on a penalty factor (which is inversely related to body's permeability κ) that must be large to enforce rigid body velocity in the solid domain. When the penalty factor is large, the discrete system of equations becomes stiff and difficult to solve numerically. In this paper, we propose a projection method-based preconditioning strategy for solving volume penalized (VP) incompressible and low-Mach Navier-Stokes equations. The projection preconditioner enables the monolithic solution of the coupled velocity-pressure system in both single phase (uniform density and viscosity) and multiphase (variable density and viscosity) flow settings. In this approach, the penalty force is treated implicitly, which is allowed to take arbitrary large values without affecting the solver's convergence rate or causing numerical stiffness. It is made possible by including the penalty term in the pressure Poisson equation (PPE), which was not included in previous works that solved VP incompressible Navier-Stokes equations using the projection method. We show how and where the Brinkman penalty term enters the PPE by re-deriving the projection algorithm for the VP method. Solver scalability under grid refinement is demonstrated, i.e., convergence is achieved with the same number of iterations regardless of the problem size. A manufactured solution in a single phase setting is used to determine the spatial accuracy of the penalized solution. Various values of body's permeability κ are considered. Second-order pointwise accuracy is achieved for both velocity and pressure solutions for reasonably small values of κ. Error saturation occurs when κ is extremely small, but the convergence rate of the solver does not degrade. The solver converges faster as κ decreases, contrary to prior experience. Two multiphase fluid-structure interaction (FSI) problems from the ocean engineering literature are also simulated to evaluate the solver's robustness and performance (in terms of its number of iterations). The proposed solver also allows us to investigate the effect of κ on the motion of the contact line over the surface of the immersed body. It also allows us to investigate the dynamics of the free surface of a solidifying metal. • A projection preconditioner for volume penalized multiphase incompressible/low Mach Navier-Stokes equations is proposed. • The new projection method considers the Brinkman penalty term in both pressure Poisson and velocity update equations. • In contrast to prior experience, the solver convergence rate improves with decrease in body's permeability. • Second-order pointwise accuracy is achieved for both velocity and pressure solutions for reasonably small permeability values. • Challenging multiphase fluid-structure interaction and phase change problems are simulated using the proposed preconditioner. [ABSTRACT FROM AUTHOR]

Among the advances made in analytical and numerical analysis methods to quantify groundwater/surface-water interaction, one methodology that stands out is the use of heat as an environmental tracer. A large data set of river and riverbed temperature profiles from the Aa River in Belgium has been used to examine the spatial-temporal variations of groundwater/surface-water interaction. Exchange fluxes were calculated with the numerical heat-transport code STRIVE. The code was applied in transient mode to overcome previous limitations of steady-state analysis, and allowed for the calculation of model quality. In autumn and winter the mean exchange fluxes reached −90 mm d−1, while in spring and early summer fluxes were −42 mm d−1. Predominantly gaining conditions occurred along the river reach; however, in a few areas the direction of flow changed in time. The river banks showed elevated fluxes up to a factor of 3 compared to the center of the river. Higher fluxes were detected in the upstream section of the reach. Due to the influence of exchange fluxes along the river banks, larger temporal variations were found in the downstream section. The exchange fluxes at the river banks seemed more driven by variable local exchange flows, while the center of the river was dominated by deep and steady regional groundwater flows. These spatial and temporal differences in groundwater/surface-water exchange show the importance of long-term investigations on the driving forces of hyporheic processes across different scales. [ABSTRACT FROM AUTHOR]