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Nitrogen is an essential component of all living organisms and a basic element for synthesizing many chemical products. However, N2 is chemically inert and inaccessible to most organisms in its original form. Therefore, it must be first converted into other more reactive forms like ammonia or nitrates in a process named “Nitrogen Fixation”. Nitrogen fixation (NF) with low energy consumption and minimal CO2 emissions is a significant challenge in today's technological landscape. The natural processes allowing NF are mostly lightning and the activity of some bacteria. The global population growth also increases food demands, thus the industrialization of agriculture using nitrogen-based fertilizers has driven the development of artificial NF processes. In the beginning of the 20th century, intensive research efforts led to the development of several industrial NF processes. The most developed processes are (I) Birkeland–Eyde (B-E) process, (II) Frank–Carlo (F-C) process, and (III) Haber–Bosch (H-B) process. As a result of high energy consumption, the first two processes were abandoned and quickly replaced by the H-B process. In the H-B process, nitrogen from air is combined with hydrogen during steam methane reforming under extremely high pressures (100−250 bar) and moderately high temperatures (500°C) in presence of an active catalyst (Fe or Ru–based catalysts) to yield a high proportion of ammonia. For a fully optimized and integrated H-B process, an energy efficiency as low as 0.48 MJ/mol of nitrogen is reported. Nevertheless, despite its effectiveness, this process consumes almost 1%–2% of the world’s total energy resources and emits more than 180 million tons of CO2 annually. In addition, a fully operational H-B process demands a large infrastructure that does not allow for decentralization on a small scale which makes the transportation requirement an additional disadvantage of this method. It is therefore necessary to develop a new NF process allowing for lower en, Doctorat en Sciences de l'ingénieur et technologie, info:eu-repo/semantics/nonPublished

Introduction: Ever since the first human reached the South Pole, studies have sought to explore the impact of an isolated, confined, and unusual environment on human adaptation. The findings have highlighted both negative and salutogenic effects on crews. Although several studies have focused on adaptation in the polar regions, we still do not fully understand its mechanisms. Thus, the objectives of the present study are: (1) to investigate the impact of a one-year stay in Antarctica on health adaptation; and (2) to assess recovery from this experience two days later. Method: Seventeen healthy participants were recruited to stay for one year at the French Dumont d'Urville station in Antarctica. Psychological, physiological, and exteroceptive measures were recorded on the day of arrival at the station (baseline), during each quarter of the wintering season (M4, M7, M10, M12), and two days after the return to the continent (D+2). Subjects were allocated to two groups according to their scores on the General Health Questionnaire at baseline, as follows: very limited or no existence of minor non-psychiatric or psychotic disorders (higher than normal, HN); and standard values for non-psychiatric or minor psychotic disorders within the general population (ordinary range, OR). Results: Our results highlight both an adaptative response during the winter months, and pathogenic states during the last quarter of the mission and at recovery (D+2), which are still below normal values for psychological disorders and stress. The analysis of OR and HN groups during overwintering highlights a decrease in psychosensory responses, and thus poorer adaptation. Conclusion: Spending a year in Antarctica no longer has harmful consequences (except during the third quarter of the mission), and the harshness of the environment in midwinter does not seem to be an aggravating factor for the winterers included in this study. Nevertheless, the General Health Questionnaire indicates two levels of, SCOPUS: ar.j, info:eu-repo/semantics/published

We consider the propagation of a stochastic SIR-type epidemic in two connected populations: a relatively small local population of interest which is surrounded by a much larger external population. External infectives can temporarily enter the small population and contribute to the spread of the infection inside this population. The rules for entry of infectives into the small population as well as their length of stay are modeled by a general Markov queueing system. Our main objective is to determine the distribution of the total number of infections within both populations. To do this, the approach we propose consists of deriving a family of martingales for the joint epidemic processes and applying classical stopping time or convergence theorems. The study then focuses on several particular cases where the external infection is described by a linear branching process and the entry of external infectives obeys certain specific rules. Some of the results obtained are illustrated by numerical examples., SCOPUS: ar.j, info:eu-repo/semantics/published

Reaction wheels are widely used in the attitude control of spacecraft due to their capability of applying control torques, greatly reducing the propellant requirements and limiting its use to reaction wheel desaturation. However, the presence of unavoidable mechanical imperfections results in significant mechanical disturbances, being applied to the spacecraft, which can severely impact the operation of sensitive payloads. These microvibrations are broadband in nature, and therefore the effective mitigation of their effects requires a high isolation factor throughout a wide frequency range. This paper presents the development and experimental verification of a six-degree-of-freedom active isolation platform for a reaction wheel, integrating a soft suspension and active control using self-sensing actuators. A reduction in the transmitted forces of 65 dB at 270 Hz was experimentally demonstrated, while exhibiting negligible amplifications by its suspension resonance, which constitute very attractive performances., SCOPUS: ar.j, info:eu-repo/semantics/published

Thermal energy storage (TES) systems have been a subject of growing interest due to their potential to address the challenges of intermittent renewable energy sources. In this context, cementitious materials are emerging as a promising TES media because of their relative low cost, good thermal properties and ease of handling. This article presents a comprehensive review of studies exploring the use of cementitious materials, particularly concrete, as sensible heat storage media at varying scales, ranging from laboratory investigations to prototype evaluations. Starting from the different kinds of energy storage systems and applications where concrete has been used as a storage media, this article reviews the important properties which makes them a suitable material for the purpose. Reported observations are discussed and summarised based on concrete mix composition/design, aggregate/addition type, size gradation, etc. and performance of these materials. Finally, different cement-based prototypes are examined highlighting their strengths and weaknesses, and general conclusions are drawn., SCOPUS: ar.j, info:eu-repo/semantics/published

Energy transitions are at the top of global agendas in response to the growing challenges of climate change and international conflict, with the EU positioning itself as playing a pivotal role in addressing climate risks and sustainability imperatives. European energy transition policies identify ‘smart consumption’ as a key element of these efforts, which have previously been explored from a predominantly technical perspective thus often failing to identify or address fundamental interlinkages with social systems and consequences. This paper aims to contribute to interdisciplinary energy research by analysing a forward looking ‘Horizon Scan’ research agenda for smart consumption, driven by the Social Sciences and Humanities (SSH). Reflecting on an extensive systematic Delphi Method exercise surveying over 70 SSH scholars from various institutional settings across Europe, we highlight what SSH scholars see as future directions for smart consumption research. Building from seven thematic areas (under which are grouped 100 SSH research questions), the study identifies three key ‘shifts’ this new smart research agenda represents, when compared to previous agendas: (1) From technological inevitability to political choice, highlighting the need for a wider political critique, with the potential to open up discussions of the instrumentalisation of smart research; (2) From narrow representation to diverse inclusion, moving beyond the shortcomings of current discourses for engaging marginalised communities; and (3) From individual consumers to interconnected citizens, reframing smart consumption to offer a broader model of social change and governance. Social Sciences and Humanities scholarship is essential to address these shifts in meaningful (rather than tokenistic) ways. This agenda and the shifts it embodies represent key tools to enable better interdisciplinary working between SSH and teams from the technical and natural sciences., SCOPUS: ar.j, info:eu-repo/semantics/published

Background and aims – A preliminary review of hawkmoth-pollinated angraecoids from Africa unveiled a remarkable case of parallel evolution of extreme column exsertion between the two species formerly classified in in the defunct genus Barombia. These belong to one clade of Aerangis, including A. gracillima and A. stelligera, and Ypsilopus sect. Barombiella, including Y. amaniensis and Y. schliebenii. The exploration of the geographical distribution of these two clades, followed by an examination of morphological variation within Y. sect. Barombiella, revealed that the disjunct population identified as Y. amaniensis from Zimbabwe represents an undescribed species. Material and methods – Occurrence records of Ypsilopus amaniensis, Y. schliebenii, Aerangis gracillima, and A. stelligera were comprehensively mapped and distribution patterns were visually analysed. Pollination syndromes and pollinaria attachment sites were inferred based on a review of floral and hawkmoth morphology. Standard herbarium practices and mining of photographs of wild and cultivated plants in social media allowed the description of the novelty. Key results – Ypsilopus zimbabweensis sp. nov. (Y. sect. Barombiella) is a narrow endemic of significant horticultural interest and it is preliminarily assessed as Endangered. The evolution of a Barombia-type column presents a parallel geographical pattern in the Aerangis gracillima–A. stelligera clade and Ypsilopus sect. Barombiella and probably induced a shift of pollen placement sites in these sphingophilous species., SCOPUS: ar.j, info:eu-repo/semantics/published

Background and aims – Podostemaceae is a family of strictly aquatic plants found in rapids and waterfalls. Despite a recent treatment in the Flore du Gabon, the family remained poorly known, with no major studies including Gabonese collections, and almost no targeted inventories since 1966. We present the first large-scale inventory of this family in Gabon, targeting Podostemaceae throughout the country, providing new additions to the flora of Gabon and many new records of poorly known species. Material and methods – Fieldwork was conducted in Gabon between 2017 and 2021. The collected specimens were primarily preserved in ethanol with associated silica gel-preserved material and photographs. Material available at BR, BRLU, LBV, MO, P, WAG, and Z/ZT was examined. For each species, information on distribution and ecology is presented, as well as a distribution map in Gabon. Key results – The 500 newly collected specimens represent 91.4% of all known collections of Podostemaceae from Gabon. Three taxa are newly recorded for the country, including one genus (Inversodicraea tenax, Ledermanniella schlechteri, and Saxicolella nana). New distribution records are also presented for 13 little-known species. Four taxa are excluded from the Gabonese flora (the genus Dicraeanthus, Inversodicraea ledermannii, Ledermanniella sanagaensis, and Macropodiella garrettii). To date, 20 species belonging to five different genera are known to occur in Gabon. A new combination is proposed for Ledermanniella nicolasii, and Inversodicraea tanzaniensis is now considered as a synonym of Inversodicraea tenax., SCOPUS: ar.j, info:eu-repo/semantics/published

This article is devoted to the numerical analysis of the full discretization of a generalized poromechanical model resulting from the linearization of an initial model fitted to soft tissue perfusion. Our strategy here is based on the use of energy-based estimates and T-coercivity methods, so that the numerical analysis benefits from the essential tools used in the existence analysis of the continuous-time and continuous-space formulation. In particular, our T-coercivity strategy allows us to obtain the necessary inf-sup condition for the global system from the inf-sup condition restricted to a subsystem having the same structure as the Stokes problem. This allows us to prove that any finite element pair adapted to the Stokes problem is also suitable for this global poromechanical model regardless of porosity and permeability, generalizing previous results from the literature studying this model., SCOPUS: ar.j, info:eu-repo/semantics/published

Understanding and predicting the dynamics of dispersed micro-objects in microfluidics is crucial in numerous natural, industrial and technological situations. In this paper, we experimentally characterized the equilibrium velocity and lateral position of various dispersed micro-objects, such as beads, bubbles and drops, in a cylindrical microchannel over an unprecedentedly wide range of parameters. By varying the dimensionless object size, the viscosity ratio, the density ratio, the Reynolds number and the capillary number, we offer an exhaustive parametric study exploring various dynamics from the non-deformable viscous regime to the deformable inertial regime, thus enabling us to highlight the sole and combined roles of inertia and capillary effects on lateral migration. Experiments are compared and agree well with a steady three-dimensional Navier-Stokes model for incompressible two-phase fluids, including the effects of inertia and possible interfacial deformations. This model enables us to propose a correlation for the object velocity as functions of, and, obtained in the limit, but valid for a larger range of values of and delimited by the validity of the linear regime. Next, we present stability maps for the centred position showing that non-deformable objects dominated by inertial effects are only stable if large enough, typically for, whereas deformable objects dominated by capillary effects can be stable for much smaller sizes, provided the viscosity ratio is outside the range, in which deformability also plays a destabilizing effect, as for inertia., SCOPUS: ar.j, info:eu-repo/semantics/published

This review covers the new developments in machine learning (ML) that are impacting the multi-disciplinary area of aerospace engineering, including fundamental fluid dynamics (experimental and numerical), aerodynamics, acoustics, combustion and structural health monitoring. We review the state of the art, gathering the advantages and challenges of ML methods across different aerospace disciplines and provide our view on future opportunities. The basic concepts and the most relevant strategies for ML are presented together with the most relevant applications in aerospace engineering, revealing that ML is improving aircraft performance and that these techniques will have a large impact in the near future., SCOPUS: re.j, info:eu-repo/semantics/published

This work presents a new application of higher order dynamic mode decomposition (HODMD) for the analysis of reactive flows. Due to the high complexity of the data analysed, consisting of more than 80 variables (i.e. temperature and chemically reacting species) a new extension of HODMD has been developed combining the multi-dimensional HODMD algorithm with classical preprocessing techniques generally used in machine learning analyses, such as principal component analysis (PCA). This new methodology has proved to be suitable to identify the main patterns driving the main dynamics of the flow, as well as to develop reduced order models grounded in physical principles. The new algorithm was tested by means of a database obtained from a Computational Fluid Dynamics simulation of an axy-symmetric time varying non-premixed co-flow nitrogen-diluted methane flame, carried out by means of a detailed kinetic mechanism. Different dynamics were identified, and they were associated to the different variables of the reactive flow analysed. Also, this algorithm has been coupled with an additional feature selection step carried out via PCA and varimax rotation. The results that were obtained by coupling PCA with varimax rotation show the outstanding capabilities of this novel methodology to compress original databases as function of the different preprocessing techniques that are used., SCOPUS: ar.j, info:eu-repo/semantics/published

In this work, three different functionalized mesoporous silica nanoparticles (MSNs) were synthesized through the co-condensation synthesis in oil/water emulsion. Hexadecyltrimethoxysilane, triethoxy-3-(2-imidazolin-1-yl)propylsilane and (3-mercaptopropyl)triethoxysilane were used as organo-substituted silica precursors with variable molar ratio with respect to tetraethylorthosilicate (TEOS, 1:4, 1:9, 1:19). The occurred functionalization was investigated by Infrared Spectroscopy and FT-Raman and 29Si {1H} CP-MAS-NMR spectroscopy. Results show that the three materials were successfully functionalized. The influence of the different pendant groups and their concentration on the mesostructured pore organization of the obtained nanoparticles respect to the non-functionalized mesoporous silica was evaluated by means of Transmission Electron Microscopy and N2 sorption measurements. Bulky aliphatic C16 chains, especially in higher concentration, causes severe changes in mesoporous structure, leading to a more heterogeneous material. The imidazoline groups, instead, change the mesostructured morphology of the pores to an irregular but more interconnected one, while the presence of mercaptopropyl groups does not bring significant modifications. The different structural modifications in pore morphology observed between the samples is due to the different interactions between derivatized silica precursors and the components of the emulsion., SCOPUS: ar.j, info:eu-repo/semantics/published

Elementary flux modes (EFMs) are an important concept in metabolic pathway analysis and for the derivation of macroscopic dynamic models. However, the computation of elementary flux vectors is facing combinatorial explosion with the size of the metabolic network, which hinders widespread application. This study proposes a systematic elementary flux mode reduction procedure to derive reduced-order dynamic models starting from an initial set of EFMs either generated by complete enumeration or subset selection. The procedure proceeds in several steps, including geometric and optimization-based criteria. The methodology ends up with a macroscopic bioreaction scheme with a reaction number smaller than that of the measured species, and shows very satisfactory prediction results, as illustrated with data of batch cultures of CHO-320 cells., SCOPUS: ar.j, info:eu-repo/semantics/published

This study studies the performance of an integral force feedback controller for increasing the damping of lightweight flexible structures. Both methods of maximum damping and (Formula presented.) optimization are used to tune the parameters of the control system. Two modifications of the integral force feedback are proposed to compensate the effects of a soft stiffness to increase the authority of the actuator. Higher damping values are obtained by adding feedback terms to the integral force feedback. Optimal tuning, required actuator force, and stability are also discussed based on an academic model of a single-degree-of-freedom cable structure., SCOPUS: ar.j, DecretOANoAutActif, info:eu-repo/semantics/published

The Arabian Peninsula exhibits extreme hot summers and has one of the world's largest population growths. We use satellite observations and reanalysis as well as climate model projections to analyze morning and evening land surface temperatures (LSTs), to refer to processes at the surface, and wet bulb temperatures (WBTs) to measure human heat stress. We focus on three regions: the Persian Gulf and Gulf of Oman, the inland capital of Saudi Arabia, Riyadh and the irrigated agricultural region in Al-Jouf, Saudi Arabia. This study shows that the time of day is important when studying LST and WBT, with current and future WBT higher in the early summer evenings. It also shows that the effect of humidity brought from waterbodies or through irrigation can significantly increase heat stress. Over the coasts of the Peninsula, humidity decreases LST but increases heat stress via WBT values higher than 25 °C in the evening. Riyadh, located in the heart of the Peninsula has lower WBT of 15 °C-17.5 °C and LST reaching 42.5 °C. Irrigation in the Al-Jouf province decreases LST by up to 10° with respect to its surroundings, while it increases WBT by up to 2.5°. Climate projections over the Arabian Peninsula suggest that global efforts will determine the survivability in this region. The projected increase in LST and WBT are +6 °C and +4 °C, respectively, in the Persian Gulf and Riyadh by the end of the century, posing significant risks on human survivability in the Peninsula unless strict climate mitigation takes place., SCOPUS: ar.j, info:eu-repo/semantics/published

Background and aims – The genus Englerodendron (Leguminosae-Detarioideae) has recently been enlarged to include Isomacrolobium and Pseudomacrolobium, and currently includes 18 tropical African species. The recent discovery of a new species in Gabon has led us to re-evaluate the delimitation of several taxa in the genus. Material and methods – This paper is based on field work by the authors in Gabon, and on a study of herbarium material from BR, BRLU, K, LBV, MO, P, and WAG; normal practices of herbarium taxonomy have been applied. Results – Englerodendron nguemae is described and illustrated as a new species, endemic to Gabon. It is remarkable for the variation in its leaves, which may be 2-jugate, 1-jugate, or unifoliolate on the same plant. The species is most similar to E. brachyrhachis, but the latter has uniformly 2-jugate leaves; E. nguemae also differs in its longer and more broadly winged leaf rachis (if present) that is convex (not flat) above, its stamen filaments pubescent at the base, and its glabrous style. Several collections from the Democratic Republic of the Congo, previously associated with E. obanense, are considered here to represent two different taxa. One of them, E. macranthum (a new combination and name at new rank based on Macrolobium isopetalum var. macranthum, which is raised to species status), is endemic to the Mayombe range and differs from E. obanense by its inflorescences branched from the base or nearly so, and its shorter 1-seeded pods. The other taxon, still imperfectly known and here treated as Englerodendron sp. A, is endemic to the Kivu region; it differs from E. obanense by its large foliaceous stipules and from E. conchyliophorum by the lack of a basal auricle on the stipules. In addition, the first records of E. leptorrhachis from Equatorial Guinea, and of E. conchyliophorum from the Republic of the Congo, are documented, and a revised key to the now 21 species (one undescribed) of Englerodendron is presented., SCOPUS: ar.j, info:eu-repo/semantics/published

Objective: To develop and validate a standardized Best Possible Medication History (BPMH) form that could be used by clinical pharmacists. Methods: The draft version was presented to a focus group and was adapted following their comments. A three-rounds e-Delphi method was used to validate content, usability and face validity of the BPMH form. We supplemented the quantitative analysis with a qualitative analysis of comments for each Delphi round. Results: The draft BPMH form contained 23 items grouped into eight tabs. Refinement of these tabs and items by the focus group resulted in 7 tabs and 21 items, which were included in the Delphi survey. The consensus was obtained for all tabs within the second round (p=0.072). Consensus was reached on 76% (16/21) of items in the third round. 20 items were included following the qualitative analysis of the experts' comments in the third round. Conclusions: The findings of this study provide data on the content of the BPMH form. This form can be used to help clinical pharmacists to collect a complete and accurate medication list on admission. It could have an impact on inpatient safety and improve inpatient management. Studies with an international e-Delphi should be conducted for wider use, SCOPUS: ar.j, info:eu-repo/semantics/published

The development of new calcium phosphate nanoparticles with excellent cytocompatibility and antibacterial properties is generating substantial interest in the biomedical field. In this regard, the present study demonstrated the synthesis of magnesium-doped biphasic calcium phosphate nanoparticles containing silver (AgMgB-NPs) via the employment of the chemical wet-precipitation method. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and ultraviolet–visible spectroscopy (UV–Vis) methods were used to confirm the successful synthesis of AgMgB-NPs. X-ray photoelectron spectroscopy (XPS) and Raman spectra indicated that Mg2+ was doped at the Ca2+ position. The excellent cytocompatibility of AgMgB-NPs was confirmed using the cell counting kit-8 (CCK-8) analysis which employed a culture of human bone marrow-derived mesenchymal stem cells (hBMSCs). Additionally, the antibacterial activity of AgMgB-NPs was evaluated using Gram-negative E. coli and Gram-positive S. aureus micro-organisms. The present study therefore developed novel calcium phosphate nanoparticles that were demonstrated to have the potential for biomedical applications., SCOPUS: ar.j, info:eu-repo/semantics/published

Background and aims – The genus Carapichea (Rubiaceae), recently resurrected and separated from Psychotria, currently includes 24 Neotropical species and is morphologically heterogeneous. A revision of the genus in the Guianas is presented here, as part of the authors’ work on the Rubiaceae treatment in the Flora of the Guianas series. Material and methods – This paper is based on a study of herbarium specimens from BBS, BM, BR, BRB, CAY, INPA, K, P, P-JJR, and U; type specimens from other herbaria were consulted online. Some of the species were also studied in the field by the authors. Normal practices of herbarium taxonomy have been applied. Results – Three species previously included in Carapichea (C. altsonii, C. nivea, and C. sandwithiana) show aberrant characters for the genus and are transferred to Notopleura; new combinations are published for the former two (N. altsonii and N. nivea). Eight species of Carapichea, one of them still imperfectly known, are recorded from the Guianas; a ninth species, C. araguariensis, is included in this revision as it is expected to occur in the region. New combinations are published for two species: Carapichea galbaoensis and C. squamelligera, based on Psychotria galbaoensis and P. squamelligera, respectively; the former species was previously included in synonymy of C. guianensis, which is here redefined in a narrower sense. The delimitation of C. ligularis is expanded to include C. pacimonica as a synonym. The first records of C. adinantha in French Guiana – and the Guiana Shield – are documented. The taxonomy of the two remaining species, C. tillettii and C. urniformis, is left unchanged. For every species a complete description is presented, as well as data on distribution, ecology, phenology, local names (when known), and a list of collections studied., SCOPUS: ar.j, info:eu-repo/semantics/published

The use of microwave heating for the thermal regeneration of a porous carbon adsorbent in adsorptive carbon capture was evaluated. In this Microwave Swing Adsorption (MSA) process, a multimode microwave oven has been used to accelerate the desorption of CO2 after the adsorption of a CO2 / N2 (15/85 v/v) mixture. Starting from a commercial activated carbon (AC) material (MSP-20X), sorbent extrudates were prepared and loaded in a Teflon column. The heating of the sorbent bed inside the microwave (MW) cavity was characterised at different locations. Although the adsorption bed is not heated uniformly due to hot spots in the multimode MW cavity, flowing a purge gas reduces the non-uniform heating during the regeneration step. This study also reports that MSA regeneration achieves extremely fast total desorption (in 56 to 79 s), the quickest regeneration reported up to date in MSA, and very rapid desorption rates allowing swift adsorption–desorption cycles. This fast desorption is associated with the extremely high heating rates achieved (100 to 400 °C/min). We show that the desorption rate is faster when using higher powers at practically identical MW energy inputs. Complete CO2 desorption can be achieved at slightly longer durations when using 2-step MW heating. When comparing the MSA results with a reference TSA process, MSA outperforms TSA, due to the higher heating rates achieved by MSA. During eleven adsorption–desorption cycles, it is evidenced that the MSA process can regenerate the adsorption bed at a high reproducibility. The microporosity of the material remained intact during the MSA, revealing that localised heating and the high heating rates are not damaging the sorbent material., SCOPUS: ar.j, info:eu-repo/semantics/published

Objectives: The spread of antibiotic resistant bacteria is an important threat for human health. Acinetobacter baumannii bacteria impose such a major issue, as multidrug- to pandrug-resistant strains have been isolated, rendering some infections untreatable. In this context, carbapenem-resistant A. baumannii bacteria were ranked as top priority by both WHO and CDC. In addition, A. baumannii bacteria survive in harsh environments, being capable of resisting to disinfectants and to persist prolonged periods of desiccation. Due to the high degree of variability found in A. baumannii isolates, the search for new antibacterials is very challenging because of the requirement of drug target conservation amongst the different strains. Here, we screened a chemical library to identify compounds active against several reference strains and carbapenem-resistant A. baumannii bacteria. Methods: A repurposing drug screen was undertaken to identify A. baumannii growth inhibitors. One hit was further characterized by determining the IC50 and testing the activity on 43 modern clinical A. baumannii isolates, amongst which 40 are carbapenem-resistant. Results: The repurposing screen led to the identification of a harmine-derived compound, called HDC1, which proves to have bactericidal activity on the multidrug-resistant AB5075-VUB reference strain with an IC50 of 48.23 µM. In addition, HDC1 impairs growth of 43 clinical A. baumannii isolates. Conclusions: We identified a compound with inhibitory activity on all tested strains, including carbapenem-resistant clinical A. baumannii isolates., SCOPUS: ar.j, info:eu-repo/semantics/published

In this study, the solubilization of waste coarse wool as a precursory step for the large-scale valorization of keratin was investigated using a green deep eutectic solvent (DES) based on L-cysteine and lactic acid. The investigation was undertaken via the response surface methodology and based on the Box–Behnken design for four process variables of temperature (70–110 °C), dissolution time (2–10 h), the mass of L-cysteine (0.5–2.5 g) in 20 mL of lactic acid, and wool load in the DES (0.2–0.6 g). Temperature was the most significant process variable influencing keratin yield from the waste coarse wool. The optimum keratin yield (93.77 wt.%) was obtained at the temperature of 105 °C, 8 h dissolution time, with 1.6 g L-cysteine in 20 mL of lactic acid using 0.5 g of wool. This study suggests L-cysteine and lactic acid as a green solvent with the potential to scale up keratin recovery from waste wool without significant destruction in the structure of the recovered keratin. Graphical abstract: [Figure not available: see fulltext.], SCOPUS: ar.j, info:eu-repo/semantics/published

This publication lays the foundation for the description of the Multiscale Boiling Experiment, which was conducted within two measurement campaigns on the International Space Station between 2019 and 2021. The experiment addresses fundamental questions about two-phase heat transfer during boiling processes. For this purpose, single or few subsequential bubbles are selectively ignited on a heated substrate using a short laser pulse. A detailed investigation of the phenomena is possible, as the boiling process is temporally slowed down and spatially enlarged in microgravity. Within the Multiscale Boiling Project, the undisturbed growth of the bubbles, the influence of a shear flow, and the influence of an electric field are investigated within the same test facility using FC-72 as working fluid. Within the project, thirteen research groups from eight countries are collaborating. Over 3000 data sets have been generated over an 11-month measurement period. In the context of this publication, besides the motivation and necessity of such investigations, the basic structure of the experiment, the objectives of the investigations, and the organization are described. Finally, first results of the investigations are presented. Therefore, this publication has the primary aim to serve as a basis for many further planned publications and present the project as a whole., SCOPUS: ar.j, info:eu-repo/semantics/published

The main purposes of this research work were to realize the potential of sludge valorization by converting the sludge into adsorbents and to investigate the performance of sludge-based adsorbents for rare earth elements (REEs) recovery from dilute aqueous solutions. Hydrochloric acid and Fenton reagents were employed as pretreatment procedures to enhance the surface area and adsorption yield. Following this, sludge-based alginate beads were prepared by using HCl treated (HT) and Fenton treated (FT) sludge materials. The chemical composition and surface chemistry of sludge-based adsorbent beads were thoroughly analyzed by state-of-the-art analytical techniques, such as Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) analysis. The prepared beads were then investigated for the recovery of REEs. The batch adsorption studies revealed that the FT sludge beads performed better in comparison to the HT sludge beads. Among REEs, the HT- and FT-sludge beads demonstrated higher affinity towards Sm3+ ions, displaying the maximum adsorption capacities of 2.83 mg/g and 4.16 mg/g, respectively, in a multi-component system (C o = 25 ppm of each REE; pH = 5, t = 24 h and dosage = 5 g/L). In conclusion, the results from this work showed that the prepared sludge-based alginate beads can be used for REEs recovery from diluted waste streams and the tested sludge treatment options were also found effective in converting the waste to resource i.e. sludge to adsorbent for REEs recovery., SCOPUS: ar.j, info:eu-repo/semantics/published

The hydropower sector has recently raised the interest in pump as turbine (PaT) that can be a valid trade-off between capital cost and performance in micro-scale installations. Nevertheless, the modest efficiency of PaTs often restricts their exploitation. In this paper, available experimental data are used to tune a numerical model which aims to investigate the effect of the pump cutwater design on the PaT performance to improve the hydraulic efficiency. Because of its finite thickness, the cutwater interferes with the flow at the runner inlet, and generates local flaws in the velocity field such as swirl and deviations of the streamlines which limit the machine performance. To identify the geometrical characteristics of the cutwater impacting on the PaT performances, different values of stretching and thickness of the cutwater are studied at variable inclination by computational fluid dynamics (CFD) simulations. A multivariate regression method is applied on the CFD results to build a surrogate model of the PaT hydraulic characteristics as a function of the geometrical parameters of the machine cutwater. Based on this model, an optimization problem is solved to identify the most advantageous geometrical asset of the PaT cutwater to maximize the efficiency. The results highlight that the length and the cutwater angle are the most affecting variables in favouring a tangential component at the entrance of the runner. The hydraulic efficiency peak of the optimized geometry results to be 86.3%, while the baseline configuration records an efficiency of 82.4%, and the Ψ−ϕ characteristic moves the best efficiency point towards higher head (+7.5%) and lower discharge (−13.0%). The proposed methodology allows identifying the best geometrical characteristics of the PaT cutwater to maximize the performances while significantly reducing the computational time., SCOPUS: ar.j, info:eu-repo/semantics/published

A state-space model for Li-ion battery packs with parallel-connected cells is introduced. The key feature of the model is an explicit solution to Kirchhoff's laws for parallel-connected packs, which expresses the branch currents directly in terms of the model's states, applied current, and cell resistances. This avoids the need to solve these equations numerically. To illustrate the potential of the proposed model for pack-level control and estimation, a method to bound the error of a state-estimator is introduced and the modeling framework is generalized to a class of electrochemical models. It is hoped that the insight brought by this model formulation will allow the wealth of results developed for series-connected packs to be applied to those with parallel connections., SCOPUS: ar.j, DecretOANoAutActif, info:eu-repo/semantics/published

The global water crisis limits the full implementation of purified water electrolysis across the world. Thus, seawater electrolysis has been identified as a powerful option to meet the requirements for sustainable production of green hydrogen without the constraint of using pure water. As in pure water electrolysis, seawater electrolysis research has been oriented to produce a durable, electrocatalytic, and selective anode. Even though seawater electrolysis was proposed for the first time in 1980, the research found on this topic grew exponentially in the last few years. Nevertheless, researchers do not give a clear insight about the impact that important variables have in the process of seawater electrolysis and, in particular, the anodic process. In this work, an in-depth literature review on articles reporting the development of various anode materials and the conditions in which they have been tested was carried out. The conclusions reveal a need to standardize some parameters for testing the anodes, such as simulated seawater composition, pH of the solution, the method through which parasitic reactions are measured and the choice of secondary reactions to be considered in the process. A standardization of these parameters will allow researchers to compare results, which in turn will allow collaborative work towards the goal of finding a feasible process for seawater electrolysis., SCOPUS: re.j, DecretOANoAutActif, info:eu-repo/semantics/published

Nanoparticles of fluorapatite (FAp Nps) were prepared by one step chemical reaction in aqueous solutions. The pH of the system was kept constant at 6 and 8. The FAp Nps were characterized with Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDAX), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The Ca/P calculated from EDAX analysis was 1.69. The results of XRD analysis and FTIR showed the presence of FAp phases. The DRX results confirm the formation of FAp with a hexagonal structure. TEM images show semispherical and elongated nanoparticles with mean diameter of 3.78 nm, 8.63 nm and 10.46 nm, when the pH and ammonia concentrations is varied. Ammonia concentration and pH influence the morphology and size of the FAp Nps., SCOPUS: ar.j, info:eu-repo/semantics/published

Ab initio transition state theory-based master equation methodologies for the calculation of rate constants have gained enormous popularity in the past decades. Nevertheless, introducing these rate constants into large kinetic schemes is a non-trivial task when large potential energy surfaces (PESs) are investigated. To determine proper phenomenological rate constants it is in fact necessary to account for the formation of all the thermodynamically stable wells considered in the master equation (ME), even if most wells do not exhibit significant secondary reactivity. Moreover, reactions involving intermediates with lifetimes comparable to the rovibrational relaxation timescale can exhibit discontinuities both in the rate constants and in the number of thermodynamically stable wells across the investigated temperature and pressure ranges. In this work, we address these problems with a “master equation-based lumping” (MEL) approach specifically designed to process the output of ME calculations of multi-well PESs. Simple kinetic simulations allow identifying both intermediate wells with limited lifetime and isomers with similar reactivity. Then, equivalent rate constants for a smaller set of pseudospecies are derived so as to reproduce the kinetics of the detailed mechanism. Our methodology is independent of any experimental data or experience-based assumptions. The power of MEL is demonstrated with three case studies of increasing complexity, namely the PES for CH3COOH decomposition, and the portions of the C5H5OH and C10H10/C10H9 PESs accessed from C5H5 + OH and C5H5 + C5H5 recombination. This work constitutes the first systematic step addressing the robust integration of rate constants derived from ME simulations into global kinetic schemes and provides a useful approach for the entire chemical kinetics community filling the gap between detailed theoretical investigations of complex PESs and the development of detailed kinetic models., SCOPUS: ar.j, DecretOANoAutActif, info:eu-repo/semantics/published

We study affine invariant 2D triangulation methods. That is, methods that produce the same triangulation for a point set S for any (unknown) affine transformation of S. Our work is based on a method by Nielson (1993) that uses the inverse of the covariance matrix of S to define an affine invariant norm, denoted AS, and an affine invariant triangulation, denoted DTAS[S]. We revisit the AS-norm from a geometric perspective, and show that DTAS[S] can be seen as a standard Delaunay triangulation of a transformed point set based on S. We prove that it retains all of its well-known properties such as being 1-tough, containing a perfect matching, and being a constant spanner of the complete geometric graph of S. We show that the AS-norm extends to a hierarchy of related geometric structures such as the minimum spanning tree, nearest neighbor graph, Gabriel graph, relative neighborhood graph, and higher order versions of these graphs. In addition, we provide different affine invariant sorting methods of a point set S and of the vertices of a polygon P that can be combined with known algorithms to obtain other affine invariant triangulation methods of S and of P. Our sorting methods provide a novel alternative to computing affine invariant geometric structures that are computationally simpler than using the AS-norm. In this work we focus on the theoretical part of affine invariant methods and as such do not provide experimental results., SCOPUS: ar.j, DecretOANoAutActif, info:eu-repo/semantics/published

An early fundamental step in ovarian cancer progression is the dissemination of cancer cells through liquid environments, one of them being cancer ascites accumulated in the peritoneal cavity. These biological fluids are highly crowded with a high total macromolecule concentration. This biophysical property of fluids is widely used in tissue engineering for a few decades now, yet is largely underrated in cancer biomimetic models. To unravel the role of fluids extracellular macromolecular crowding (MMC), we exposed ovarian cancer cells (OCC) to high molecular weight inert polymer solutions. High macromolecular composition of extracellular liquid presented a differential effect: i) it impeded non-adherent OCC aggregation in suspension and, decreased their adhesion; ii) it promoted adherent OCC migration by decreasing extracellular matrix deposition. Besides, there seemed to be a direct link between the extracellular MMC and intracellular processes, especially the actin cytoskeleton organization and the nucleus morphology. In conclusion, extracellular fluid MMC orients OCC dissemination phenotype. Integrating MMC seems crucial to produce more relevant mimetic 3D in vitro fluid models to study ovarian dissemination but also to screen drugs., SCOPUS: ar.j, DecretOANoAutActif, info:eu-repo/semantics/published

Excess atmospheric ammonia (NH3) leads to deleterious effects on biodiversity, ecosystems, air quality and health, and it is therefore essential to monitor its budget and temporal evolution. Hyperspectral infrared satellite sounders provide daily NH3 observations at global scale for over a decade. Here we use the version 3 of the Infrared Atmospheric Sounding Interferometer (IASI) NH3 dataset to derive global, regional and national trends from 2008 to 2018. We find a worldwide increase of 12.8 ± 1.3 % over this 11-year period, driven by large increases in east Asia (5.80 ± 0.61% increase per year), western and central Africa (2.58 ± 0.23 % yr-1), North America (2.40 ± 0.45 % yr-1) and western and southern Europe (1.90 ± 0.43 % yr-1). These are also seen in the Indo-Gangetic Plain, while the southwestern part of India exhibits decreasing trends. Reported national trends are analyzed in the light of changing anthropogenic and pyrogenic NH3 emissions, meteorological conditions and the impact of sulfur and nitrogen oxides emissions, which alter the atmospheric lifetime of NH3. We end with a short case study dedicated to the Netherlands and the 'Dutch Nitrogen crisis' of 2019., SCOPUS: re.j, info:eu-repo/semantics/published

In this paper, a modified active tuned inerter damper concept which is more suitable for practical applications is proposed. The proposed device is composed of a pair of collocated reactive actuator and force sensor. A second-order low-pass filter and a proportional term are combined to form the controller. The equivalent mechanical model of the controller's components is derived in order to better interpret the coupled system. The second-order low-pass filter is mechanically equivalent to a pure mechanical network which comprises an inerter, a spring and a damper connected in parallel. The proportional term mechanically represents a spring which is connected in series with the inherent actuator spring. Simple regressions are derived based on the ℍ∞ optimisation criterion wherein the optimal feedback gains are calculated to minimise the maximal response of the driving-point receptance of the system. The numerical study is also experimentally validated. The obtained results are found to correspond well with the theoretical developments., SCOPUS: ar.j, info:eu-repo/semantics/published

Methane/hydrogen combustion represents a concrete solution for the energy scenario to come. Indeed, the addition of hydrogen into the natural gas pipeline is one of the solutions foreseen to reduce CO2 emissions. Nevertheless, the replacement of methane by hydrogen will enhance the reactivity of the system, increasing NOx emissions. To overcome this issue, non-conventional combustion technologies, such as flameless combustion represent an attractive solution. This study aims to improve our understanding of the behaviour of methane/hydrogen blends under flameless conditions by means of experiments and simulations. Several experimental campaigns were conducted to test fuel flexibility for different methane/hydrogen blends, varying the injector geometries, equivalence ratio and dilution degree. It was found that a progressive addition of hydrogen in methane enhanced the combustion features, reducing the ignition delay time and loosing progressively the flameless behaviour of the furnace. Reducing the air injector diameter or increasing the fuel lance length were found to be efficient techniques to reduce the maximum temperature of the system and NOx emissions in the exhausts, reaching values below 30 ppm for pure hydrogen. MILD conditions were achieved up to 75%H2 in molar fraction, with no visible flame structures. Additionally, RANS-based simulations were also conducted to shed further light on the effect of adding hydrogen into the fuel blend. A sensitivity study was conducted for three different fuel blends: pure methane, an equimolar blend and pure hydrogen. The effect of chemistry detail, mixing models, radiation modeling and turbulence models on in-flame temperatures and NOx emissions was also studied. In particular, it was found that the usage of detailed chemistry for NOx, coupled with an adjustment of the PaSR model, filled the gap between experiments and predictions. Finally, a brute-force sensitivity revealed that NNH is the most important route for NOx pro, SCOPUS: ar.j, info:eu-repo/semantics/published

The development of biomineralized hydrogels with excellent cytocompatibility is of great importance for tissue engineering applications. Here, porous polyvinyl alcohol/alginate/biphasic calcium phosphate (BPS) hydrogels were fabricated via chemical and physical crosslinking methods, and the BPS hydrogels were in vitro biomineralized using urease in saturated calcium-phosphorus solution. For comparison, the BPS hydrogels were also treated using simulated body fluid (SBF) and Dulbecco's modified Eagle's medium with fetal bovine serum (DMEM-FBS), respectively. The physicochemical characterizations confirmed that bone-like apatite was quickly formed on the urease-biomineralized BPS hydrogels compared to the SBF and DMEM-FBS treated hydrogels. Additionally, the bone marrow derived mesenchymal stem cells (BMSCs), adhered and proliferated on the biomineralized hydrogels, were systematically analyzed using cell counting kit-8 (CCK-8). This paper demonstrated the potential urease for fast in vitro biomineralization on hydrogels to improve the cytocompatibility for bone tissue engineering applications., SCOPUS: ar.j, info:eu-repo/semantics/published

In this paper we investigate the statics and the dynamics of large-viscosity ligaments attached to a rod and drawn out of a pure-liquid bath. Following the similar work of films pulling out of a bath (Champougny et al. J. Fluid Mech. vol. 811, 2017, pp. 499-524), a one-dimensional model is applied to describe the ligaments drawn at constant velocities. We focus on the whole drawing dynamics of the ligament up to breakup, for which the breakup height is determined. The breakup height coincides with the maximum static meniscus height for very slow drawing, whose process can be described by quasi-static solutions. We present the numerical results of the static menisci and analytically unravel the mechanism in the low gravity case. Starting from a stable static meniscus, the breakup height of faster drawing depends separately on the rod radius and the drawing velocity, the latter dependency being fully determined by considering the agravic limit. Next, it is shown that the entire lifetime of the ligament drawing can be sequenced into a ductility stage, a capillarity stage and a pinch-off stage, the latter being shown to be almost instantaneous. The ductility and capillarity stages are decorrelated with the help of an approximate solution of the ductility stage, and the transition between the two stages corresponds to the time at which the capillarity-induced contraction velocity exceeds the ductility-induced one. The one-dimensional predictions of the breakup height and the entrained liquid volume attached to the rod quantitatively agree with experimental results of silicone oil ligaments, and the deviations are rationalized in comparison with a two-dimensional model., SCOPUS: ar.j, info:eu-repo/semantics/published

The jet wiping process is a cost-effective coating technique that uses impinging gas jets to control the thickness of a liquid layer dragged along a moving strip. This process is fundamental in various coating industries (mainly in hot-dip galvanizing) and is characterized by an unstable interaction between the gas jet and the liquid film that results in wavy final coating films. To understand the dynamics of the wave formation, we extend classic laminar boundary layer models for falling films to the jet wiping problem, including the self-similar integral boundary layer and the weighted integral boundary layer models. Moreover, we propose a transition and turbulence model to explore modelling extensions to larger Reynolds numbers and to analyse the impact of the modelling strategy on the liquid film dynamics. The validity of the long-wave formulation was first analysed on a simpler problem, consisting of a liquid film falling over an upward-moving wall, using volume of fluid simulations. This validation proved the robustness of the integral formulation in conditions that are well outside their theoretical limits of validity. Finally, the three models were used to study the response of the liquid coat to harmonic and non-harmonic oscillations and pulsations in the impinging jet. The impact of these disturbances on the average coating thickness and wave amplitude is analysed, and the range of dimensionless frequencies yielding maximum disturbance amplification is presented., SCOPUS: ar.j, info:eu-repo/semantics/published

In a channel flow with a sudden expansion, whether for three-dimensional (3-D) pipe and channel flows, or for two-dimensional (2-D) channel flow, it is known that increasing the Reynolds number beyond a critical value induces a symmetry breaking Pitchfork bifurcation. The linear stability analysis of the symmetric steady solution enables the to be determined efficiently and thus the influence of the expansion ratio ,defined as the ratio between upstream and downstream diameter regarding the expansion, to be explored. In this study, we investigate the behaviour of the flow after 2-D sudden expansions while varying the and the inlet flow profile, e.g. corresponding to a transition profile between a plug and a Poiseuille flow that could be reached for a flow after a sudden constriction upstream. Results demonstrate that imposing a plug flow at the inlet gives a higher than any other profile and that the concomitant recirculation zones are shorter. We show that these results can be rationalized using basic convection-diffusion arguments., SCOPUS: ar.j, info:eu-repo/semantics/published

We study the role of hydrodynamic instabilities in the morphogenesis of some typical karst draperies structures encountered in limestone caves. The problem is tackled using the long wave approximation for the fluid film that flows under an inclined substrate, in the presence of substrate variations that grow according to a deposition law. We numerically study the linear and nonlinear evolution of a localized initial perturbation both in the fluid film and on the substrate, i.e. the Green function. A novel approach for the spatio-temporal analysis of two-dimensional signals resulting from linear simulations is introduced, based on the concepts of the Riesz transform and the monogenic signal, the multidimensional complex continuation of a real signal. This method allows for a deeper understanding of the pattern formation. The linear evolution of an initial localized perturbation in the presence of deposition is studied. The deposition linearly selects substrate structures aligned along the streamwise direction, as the spatio-temporal response is advected away. Furthermore, the growth of the initial defect produces a quasi-steady region also characterized by streamwise structures both on the substrate and the fluid film, which is in good agreement with the Green function for a steady defect on the substrate, in the absence of deposition., SCOPUS: ar.j, info:eu-repo/semantics/published

Simulations of atmospheric entry of spacecraft and satellites require accurate knowledge of thermo-physical properties such as heat capacity in a wide temperature range. However, the characterization of this quantity is not straightforward for carbon composites at high temperatures, due to pyrolysis reactions that occur in the material. We develop a methodology for determining the heat capacity and required heat of pyrolysis for carbon composites in these conditions. The methodology consists of three steps: organic elemental analysis to determine composition, differential scanning calorimetry experiments on the different components to determine apparent heat capacity, and computations to separate the apparent heat capacity into heat capacity and heat of pyrolysis. This methodology is applied to the ZURAM® carbon/phenolic ablator from room temperature up to 1100 K. The results obtained were compared to separate analyzes of the different components of the material, assuming that heat capacity is an additive property. It was found that compressing the samples into disks provides improved resolution and repeatability for low density materials. This provided a determination of the heat capacity of the decomposing composite with a relative standard deviation <10% and of <20% for the heat of pyrolysis. The proposed methodology can directly be applied to other carbon composites such as carbon/epoxy systems., SCOPUS: ar.j, info:eu-repo/semantics/published

A new concept of vapour condenser is proposed to solve the drainage problem and to provide an effective condensate flow under weightlessness conditions. The concept combines the capability of a curvilinear surface to drive liquid, and a combination of a porous media and a pump, as an active condensate retraction system. The porous media collects and stores the condensed fluid and acts as a barrier for the vapour phase. Hydrodynamic validation of the liquid flow was done against retraction overflow under terrestrial conditions. It was figured out that the time available for adjusting the retraction system to avoid film disturbances decreased non-linearly with an increase in retraction overflow. The behaviour of the proposed condenser with the retraction system was tested under weightlessness condition during the ESA parabolic flights campaign as a part of concept validation. Three porous media with different values of the pore size and material were tested. It was found that the combination of the pump and porous media helped to improve the condensate flow. It was observed that the stabilisation effect was influencing the condensate flow not only during weightlessness condition but also under acceleration disturbances during the campaign., SCOPUS: ar.j, info:eu-repo/semantics/published