Main Scientific Issues Research Articles

Spatiotemporal Variations in Carbon Sources and Sinks in National Park Ecosystem and the Impact of Tourism

The capacity of carbon sinks varies among the different types of ecosystems, and whether national parks, as an important type of nature reserve, have a high carbon sink capacity (CSC) and whether eco-tourism in national parks affects their CSC are the main scientific issues discussed. Using MODIS Net Primary Production (NPP) product data, this study analysed the spatiotemporal variation in carbon sources and sinks (CSSs) in the ecosystem of Huangshan National Park from 2000 to 2020, as well as the impact of tourism on these carbon sources and sinks. The findings indicate that, while the ecosystems of national parks generally have a strong CSC, they may not always function as carbon sinks, and during the study period, Huangshan National Park served as a carbon source for four years. Temporally, the CSSs in the ecosystem of the national park exhibit a cyclical pattern of change with a four-year cycle and strong seasonality, with spring and autumn functioning as carbon sinks, and summer and winter as carbon sources. Spatially, the CSSs of the national park ecosystem exhibited a vertical band spectrum of spatial distribution, and the CSC showed a trend of gradual enhancement from low altitude to high altitude. Tourism is a major factor that has an impact on the CSC of national park ecosystems.

Prospects in Sustainable Hydrosilylation by Biphase Catalysis

AbstractThis concept addresses the main economic, environmental, scientific and technological issues associated with the use of homogeneous Pt‐catalysts in the important industrial hydrosilylation process. The development of biphase catalysis is proposed as the most promising approach. One solution we suggest is the use of ethylene glycol (EG) as a medium in biphase catalysis. We have previously shown that EG in Pt‐catalyzed hydrosilylation serves not only as a medium but also as a mild reducing agent of Pt‐ions to Pt0, as well as an effective ligand for the preparation of mononuclear Pt01‐complexes. These zero valent platinum complexes are single‐atom catalysts (SAC) and have high activity in hydrosilylation, stability during storage and the ability to be recycled multiple times (~40 times). This option of using an atomic catalyst allows us to combine the advantages of homogeneous and heterogeneous catalysts.

Research progresses and main scientific issues of strategically critical minerals in black rock series

Research progresses and main scientific issues of strategically critical minerals in black rock series

The Matterhorn, an emblematic mountain in Switzerland, the time scales of a geomorphosite

The Matterhorn, a famous mountain in the Swiss Alps is a well characterized geomorphosite, presenting both an important scientific interest and aesthetic, cultural and economic values in Switzerland. The main scientific issues concerning the Matterhorn are its place in the tectonic history of the Alps, the carving of a residual pyramid by glacial erosion and the effects of melting of high mountain permafrost on mountaineering. To answer those questions, two “tools” were used, the field work and the bibliographic investigations. The Matterhorn played, from its first ascent in 1865 until today, a very special role in the history of mountaineering, and its remarkable shape has become iconic in Switzerland. As a consequence, the Matterhorn can be analyzed through four time scales:(1) the deep time of tectonics during the Cenozoic era, which saw the thrusting and piling up of the “Pennine nappes,” due to the collision between African and European plates; (2) the Quaternary period of glacial erosion, which carved the Matterhorn into its distinctive pyramidal peak shape;(3) the Anthropocene time of the thawing of high mountain permafrost; and (4) the era of humans or mountaineering, which spans over than 150 years, from the first ascent in 1865 to the recent achievements of modern mountaineering.

Frontiers in homogenization methods towards generalized continua for architected materials

Architected materials have witnessed tremendous research activity in the last two decades, due to their ability to achieve unprecedented effective properties. The up-scaling of the mechanical response towards an effective continuum is challenging, due to the possible emergence of a homogenized macroscopic behavior that may substantially differ from that of the base material at the micro level. The need for enriched continuum models beyond Cauchy’s theory arises due to the existence of a new class of artificial materials exhibiting static and dynamic attributes typically not encountered in natural materials, deserving the name meta-materials. In such a situation with a failure of the strict scale separation hypothesis, the enrichment of the Cauchy continuum proceeds by adding new intrinsic parameters and internal length scales representative of the micro-structural impact at the level of the effective medium. Generalized continua including either new kinematic variables or higher gradients of the displacement have proven their ability to provide a faithful description of the response of materials with micro-structural effects; their derivation from a micro-mechanical approach starting directly from the scale of the microstructure raises specific difficulties, in contrast to the phenomenological standpoint, which however lacks a predictive capacity. A survey of the scientific issues raised by higher-order homogenization methods towards generalized continua is provided in this contribution. The main scientific issues and challenges raised by higher-order homogenization methods are reviewed in a critical manner, and solutions to these scientific issues are proposed in light of the more recent contributions. Specific attention is devoted to the elaboration of enriched models for architected materials in both static and dynamic regimes.

Solid‐State Batteries Based on Organic Cathode Materials

AbstractOrganic cathode materials (OCMs) possess high resource sustainability, large structural diversity, high theoretical energy density, and potentially low cost, however, suffer from the dissolution problem in liquid non‐aqueous electrolyte. Solid‐state batteries (SSBs) are regarded as the final solution of Li and Na metal batteries because of the intrinsic safety, but hindered by many challenges including the poor contact with rigid inorganic cathode materials. Therefore, applying OCMs in SSBs is probably a win‐win strategy to compensate for their respective deficiency. In this review, some fundamental knowledge of OCMs and SSBs are briefly introduced at first, with emphasis on different types of solid‐state electrolytes (SSEs). Then the reported works on OCM‐based SSBs are summarized by classifying them into non‐ceramic, semi‐ceramic, and all‐ceramic ones. Finally, we conclude our understandings on the main scientific issues and possible solutions. To sum up, the combination of OCMs and SSBs brings about many new challenges but also opportunities towards their practical application.

Artificial intelligence applied in pulmonary hypertension: a bibliometric analysis.

Advances in Artificial Intelligence (AI) offer new Information Technology (IT) opportunities in various applications and fields (industry, health, etc.). The medical informatics scientific community expends tremendous effort on the management of diseases affecting vital organs making it a complex disease (lungs, heart, brain, kidneys, pancreas, and liver). Scientific research becomes more complex when several organs are simultaneously affected, as is the case with Pulmonary Hypertension (PH), which affects both the lungs and the heart. Therefore, early detection and diagnosis of PH are essential to monitor the disease's progression and prevent associated mortality. The issue addressed relates to knowledge of recent developments in AI approaches applied to PH. The aim is to provide a systematic review through a quantitative analysis of the scientific production concerning PH and the analysis of the networks of this production. This bibliometric approach is based on various statistical, data mining, and data visualization methods to assess research performance using scientific publications and various indicators (e.g., direct indicators of scientific production and scientific impact). The main sources used to obtain citation data are the Web of Science Core Collection and Google Scholar. The results indicate a diversity of journals (e.g., IEEE Access, Computers in Biology and Medicine, Biology Signal Processing and Control, Frontiers in Cardiovascular Medicine, Sensors) at the top of publications. The most relevant affiliations are universities from United States of America (Boston Univ, Harvard Med Sch, Univ Oxford, Stanford Univ) and United Kingdom (Imperial Coll London). The most cited keywords are "Classification", "Diagnosis", "Disease", "Prediction", and "Risk". This bibliometric study is a crucial part of the review of the scientific literature on PH. It can be viewed as a guideline or tool that helps researchers and practitioners to understand the main scientific issues and challenges of AI modeling applied to PH. On the one hand, it makes it possible to increase the visibility of the progress made or the limits observed. Consequently, it promotes their wide dissemination. Furthermore, it offers valuable assistance in understanding the evolution of scientific AI activities applied to managing the diagnosis, treatment, and prognosis of PH. Finally, ethical considerations are described in each activity of data collection, treatment, and exploitation to preserve patients' legitimate rights.

Using Mini-CT Specimens for the Fracture Characterization of Ferritic Steels within the Ductile to Brittle Transition Range: A Review

The use of mini-CT specimens for the fracture characterization of structural steels is currently a topic of great interest from both scientific and technical points of view, mainly driven by the needs and requirements of the nuclear industry. In fact, the long-term operation of nuclear plants requires accurate characterization of the reactor pressure vessel materials and evaluation of the embrittlement caused by neutron irradiation without applying excessive conservatism. However, the amount of material placed inside the surveillance capsules used to characterize the resulting degradation is generally small. Consequently, in order to increase the reliability of fracture toughness measurements and reduce the volume of material needed for the tests, it is necessary to develop innovative characterization techniques, among which the use of mini-CT specimens stands out. In this context, this paper provides a review of the use of mini-CT specimens for the fracture characterization of ferritic steels, with particular emphasis on those used by the nuclear industry. The main results obtained so far, revealing the potential of this technique, together with the main scientific and technical issues will be thoroughly discussed. Recommendations for several key topics for future research are also provided.

A review of the recent progress on direct heterogeneous catalytic CO2 hydrogenation to gasoline-range hydrocarbons

This review presents important progress, main catalytic systems and critical scientific issues on direct heterogeneous catalytic CO2 hydrogenation to gasoline-range hydrocarbons.

ПРОБЛЕМАТИКА ОЦІНКИ МАКРОЕКОНОМІЧНОГО ВПЛИВУ НА ЙМОВІРНОСТІ КРЕДИТНОГО ДЕФОЛТУ В УМОВАХ ВИСОКОЇ НЕВИЗНАЧЕНОСТІ

The article analyzes the current state of scientific and practical approaches to assessing the probability of credit default of financial instruments. The main scientific and practical issues related to the assessment of PD PIT financial instruments in the conditions of large-scale military aggression by Russia are defined. Specific requirements for the methodology of creating more adequate models for assessing the probability of credit default on the PIT basis, i.e. taking into account the influence of macroeconomic factors on this indicator, were also determined. The research was carried out and the process of creating mathematical models was formalized to determine the probability of credit default in the context of the impact of macroeconomic processes caused by catastrophic, but not shock, changes in the economic system and its subsequent partial recovery due to military events. The authors concluded that there is currently a significant shortage of simulation experience in military settings, which makes it difficult to develop an adequate assessment methodology. The possibility of building a complex family of PITTTC models, which directly relate system-sensitive probabilities to the corresponding PD TTC stress values, was investigated. The possibilities and limitations of the application of the PITTTC family of models to determine the probabilities of credit default in conditions of high uncertainty caused by the war, which is still ongoing, are analyzed. Thus, this work substantiates the need for a complete revision of the methodology for assessing the probability of credit default in conditions of high uncertainty in the risky economic environment caused by military actions. It is also determined that the new methodology should solve the problem not only of the lack of historical data for the validation of relevant models, but also to create new assessment models that should correspond to the current crisis state of the Ukrainian economy. The work suggests specific ways for further research into this problem.

The main issues of interest research

The article considers interest as a social phenomenon characterized by its internal inconsistency and manifesting itself both in objective social reality and in the subjective perception of a social subject. The transformation of interest from objective to subjective and vice versa is analyzed. On the basis of this transformation, the main scientific issues of interest research related to the interaction of group, public and personal interests, their awareness, transformation into the main driving force of social activity of subjects, as well as the possibilities of its regulation by taking into account interests, are described. Special emphasis is placed on the study of the processes of formation of social subjectivity involving the spheres of communication, activity and self-consciousness of a social subject. Consideration of interests as the main elements of the process of socialization allows us to explore their transformation during the assimilation and reproduction of social experience, affecting such important processes as interiorization, identification and self-realization. The analysis of interests, taking into account the peculiarities of social and individual aspects of socialization, shows their role in ensuring the successful functioning of a social subject in society. The article describes in detail the difficulties of taking into account interests in the course of regulating social relations and substantiates the causes of existing problems of interest research related to both external factors of society development and internal factors of personal interest formation. The significant directions of research of interests in modern conditions of development of society are determined, contributing to the awareness of problematic areas of their study, understanding of the social foundations of social processes and the development of sociological ideas about the structure and content of social actions.

Analysis of Sub-Daily Precipitation for the PannEx Region

The PannEx is a GEWEX-initiated, community driven research network in the Pannonian Basin. One of the main scientific issues to address in PannEx is the investigation of precipitation extremes. Meteorological Services in the PannEx area collected the hourly precipitation data and commonly used a computer program, which was developed in the INTENSE project, to produce a set of global hydro-climatic indices. Calculations are carried out on data aggregated 1-, 3- and 6-h intervals. Selected indices are analyzed in this paper to assess the general climatology of the short-term precipitation in the Pannonian basin. The following indices are illustrated on maps and graphs: the annual mean and maxima of 1-h, 3-h and 6-h sums, the count of 3-hr periods greater than 20 mm thresholds, the maximum length of wet hours, the timing of wettest hour and the 1-h precipitation intensity. The seasonal trends of the 1-h precipitation intensity were tested from 1998 to 2019. Analysis of sub-daily precipitation has been limited by the availability of data on a global or a regional scale. The international effort made in this work through collaboration in the PannEx initiative contributes to enlarging the data availability for regional and global analysis of sub-daily precipitation extremes.

Epidemiology of myopia: iteration and progression

Adolescent myopia has become one of the researchers' focuses among visual problems around the world. Carrying out a scientific and efficient epidemiological study on myopia is an essential basis for discovering the rules of the occurrence and the development of myopia, exploring related influencing factors and identifying the mechanisms, which are critical for the policy-making for myopia control. The epidemiological studies of myopia at home and abroad have a long history of exploration, standardization and unification, and are enriched by new technologies and up-to-date discoveries. Based on the characteristics of social development and the prevalence of adolescent myopia in the past six decades, the epidemiological studies on myopia are divided into four stages in this article. Each stage is specified and analyzed to identify the difference in research methods and strategies. The main scientific issues and research elements in the current epidemiology of myopia in adolescents are put forward. (Chin J Ophthalmol, 2021, 57:245-250).

A multiphysics model of large-scale compact PV–CSP hybrid plants

Do compact Photovoltaic–Concentrated Solar Power hybrid systems offer the opportunity for the expansion of the global solar market? Despite the inherent potential of this technology to provide both affordable and dispatchable solar electricity, it is still unclear how the combination of Photovoltaic and Concentrated Solar Power may offer a net advantage over conventional solar plants. Herein, large-scale compact Photovoltaic–Concentrated Solar Power hybrid plants are modeled considering two different hybrid approaches, over a whole year operation, and compared with a conventional Concentrated Solar Power plant. A detailed optical, electrical and thermal model is developed to analyse the temporal output characteristics of the hybrid plants, based on realistic input parameters and representative meteorological data in Targassonne, France. Results show that both hybrid systems may deliver significantly higher energy output over the conventional Concentrated Solar Power plant, provided that several key parameters are optimized. Furthermore, the sensitivity of the two-hybrid strategies investigated to the operating conditions, and to the characteristics of the solar cells used, are analyzed. In the light of these results, the main scientific and technological issues one should address to ensure optimal operation of these compact hybrid plants are finally discussed.

Frontiers and prospects of integrated microwave photonics (Invited)

Microwave photonics is an interdisciplinary subject of microwave engineering and photonics technology. It is a fused microwave and optical system that studies the interaction between optical and microwave signals in the medium and the generation, processing, transmission, and receiving of microwave signals in the optical domain. Integration is an inevitable trend of microwave photonics since the performances of current discrete devices-based microwave photonic systems are poor in terms of size, power consumption, stability and cost. The main scientific and technical issues of integrated microwave photonics were discussed, its development status and frontier research progresses were summarized, and an outlook of its future prospects was given.

Hygrothermal behaviour of flax shives used as insulation material in an attic of a traditional house

Western Europe area is one of the world regions where traditionally flax is grown. Whether in France or Belgium, flax is mainly used for the production of fabrics. When separating the different components of the plant, small woody elements called shives which represented about 50% of the production, are recovered. This work aims to study the behavior of flax shives used as insulation material in an attic of a French Flanders traditional house. Main scientific issues related to the study of heat and mass transfer is to determine the evolution of the thermal characteristics of the material and its durability. First, we propose a laboratory analysis of the hygrothermal behavior of shives by conventional thermal methods for characterizing thermal conductivity and volumetric heat (heat flux method), sorption curve is also determined. Then we focus on an experimental site which is an independent house where the old insulation of the attic in glass wool was replaced by flax shives. The hygrothermal behavior of this new insulation was monitored with humidity and temperature sensors for ten months. The thermal performances determined for a raw form of the shives in the laboratory are encouraging and hygrometric results show advantageous behavior whatever the season.

Этнография казахского народа в работах Григория Николаевича Потанина

Purpose. In the conditions of accelerated development of modernization processes in Kazakhstan, there is increased interest in the study of Kazakh heritage by historians and ethnographers of the 19th – 20th centuries. The purpose of this work is to identify the main scientific issues in the ethnography of the Kazakhs covered in Grigorii Nikolaevich Potanin’s studies. Scientific works of this outstanding scientist in this respect are particularly relevant. Firstly, the researcher was born in one of the fortifications in the Kazakh steppe and had a good command of the Kazakh language as he was familiar with the peculiarities of culture and life of the Kazakh people since his childhood. Secondly, he was a famous ethnographer, a member of the Russian Geographical Society and participated in several scientific expeditions on the territory of Kazakhstan, Mongolia, China. This article deals with studying the traditional culture of the Kazakh people by the famous ethnographer G. N. Potanin (1835–1920). We analyze the main works of the researcher devoted to the study of the spiritual culture of the Kazakh people. On the basis of our study, we identify that the study of folklore was one of central and most important issues among the various scientific aspects G. N. Potanin raised. Results. G. N. Potanin focused on studying oral folk art of the Kazakh people including genealogical legends. He analyzed the origin of those legends and their similarities with legends of other peoples. The researcher also collected and recorded fairy tales, proverbs, riddles and tongue twisters of the Kazakh people. G. N. Potanin proved the so-called “eastern hypothesis” of the origin and development of the medieval European epic. In our opinion, G. N. Potanin concentrated on studying oral folk art because it reflects the life of the Kazakh people. The researcher noted a certain influence of Islam and Central Asian culture on the traditional culture of the Kazakh people. He studied ethnic composition, social structure, traditional economy and material culture of the Kazakh people. Conclusion. Thus, the study of Kazakh folklore, including oral and musical creativity, was the main important issue in G. N. Potanin’s research. He made conclusions on the ethnic composition, the traditional system of life support of the Kazakh people. In this small work, we noted only a small range of aspects that are reflected in the work of the great researcher. It is necessary to widen the range of archival materials studied to continue investigating the heritage of this outstanding Russian scientist, a true friend of the Kazakh people.

(Invited) Small Angle Scattering As Unique Probe to Quantify Water Distribution and Ionomer Structure in Operating PEMFC

The Proton Exchange Membrane Fuel Cell (PEMFC) is a highly complex energy conversion device coupling several electrochemical and transport phenomena occurring on a wide range of length-scales within a multilayered structure, named Membrane Electrodes Assembly (MEA). The fundamental description of all phenomena involved in PEMFC operation and degradation, and more particularly their interplay, is a contemplated pivotal requirement for improvements. This is a grand challenge, as a number of unsolved questions remain. In fact, all relevant physical and electrochemical phenomena are not fully identified or quantified. In the PEMFC, water plays a crucial role, since it is not only the main product of the electrochemical reaction but, above all, it is the fundamental common denominator to all the phenomena. In a real stack, as an open system converting H2 and O2, the operation and degradation are intrinsically heterogeneous resulting especially in a complex 3D distribution of water in the volume of the MEA. Among the most important component of the MEA is the ionomer, made of a PerFluoroSulfonic Acid (PFSA) polymer, which acts as a solid electrolyte to transfer proton and water to, from, and within the electrodes. The presence of highly hydrophilic sulfonic acid groups makes it, most probably, the most sensitive MEA component toward water activity/content. Indeed, it governs its swelling, structure as well as transport and mechanical properties. This property of the ionomer, along with its role, explains why PEMFC behaviour is so dependent on water activity. Still very recently, a work of Kongkanand et al.[1] emphasizes how ionomer is a crucial electrodes' constituent in view of enhancing performance. For these reasons, many researches are still devoted to studying the ionomer in relation with water activity and as well as to quantifying the 3D water distribution during PEMFC operation. It is well known that Small Angle Scattering (SAS) is the most suitable technique to characterize the structure of the ionomer[2]. A side from that, neutron is the probe of choice to quantify water within operating PEMFC[3]. For these reasons, we have been developing for several years SAS techniques, either with Neutrons or X-Ray, in order to measure simultaneously and operando, the water distribution and the ionomer nanostructure. Spatial and time resolutions offew µm² and 50 ms, respectively, have been achieved with the last generation of X-Rays sources such as the one of European Synchrotron Radiation Facility (ESRF), and ~4 mm² and 30 s with high neutron flux on D22 beamline at Laue Langevin Institute (ILL)[4],[5]. Thus, it is possible to follow the kinetics during transient. In particular, we have shown that, within the membrane, local water content is greater in front of the current collecting rib than in front of the gas supply channel. We have also evidenced some evolution of the physical structure of the membrane upon aging in real conditions depending on the local water content. We thus pushed forward these techniques, which now allows us to have unique information on the local water activity and ionomer structure within the CL. Our results demonstrate how SAS techniques are powerful to assess the main current scientific and technological issues of the PEMFC. [1] Kongkanand et al., ACS Energy Lett. 2018, 3, 618−621 [2] Fumagalli et al., J. Phys. Chem. B 2015, 119, 7068−7076 [3] Boillat et al., Current Opinion in Electrochemistry 2017, 5, 3–10 [4] Morin et al., J. Electrochem. Soc. 2016, 163, F9-F21 [5] Martinez et al., ACS Advanced Energy Materials 2019 Figure 1

Conservation metagenomics: a new branch of conservation biology.

Multifaceted approaches are required to monitor wildlife populations and improve conservation efforts. In the last decade, increasing evidence suggests that metagenomic analysis offers valuable perspectives and tools for identifying microbial communities and functions. It has become clear that gut microbiome plays a critical role in health, nutrition, and physiology of wildlife, including numerous endangered animals in the wild and in captivity. In this review, we first introduce the human microbiome and metagenomics, highlighting the importance of microbiome for host fitness. Then, for the first time, we propose the concept of conservation metagenomics, an emerging subdiscipline of conservation biology, which aims to understand the roles of the microbiota in evolution and conservation of endangered animals. We define what conservation metagenomics is along with current approaches, main scientific issues and significant implications in the study of host evolution, physiology, nutrition, ecology and conservation. We also discuss future research directions of conservation metagenomics. Although there is still a long way to go, conservation metagenomics has already shown a significant potential for improving the conservation and management of wildlife.

Tuning lattice spacing in titanate nanowire arrays for enhanced sodium storage and long-term stability

Fabricating high-performance anode materials is of great significance for the realization of advanced Na-ion batteries (SIBs). Poor rate capability and insufficient cycle stability are two main scientific issues urgently needing to be solved for sodium titanate (NaxTiyOz) anodes. In this paper, protonated titanate nanowire arrays are designed rationally as novel additive-free anodes for SIBs. Results reveal that the protonated strategy can controllablly regulate the lattice interlayer spacing of the titanate, which can not only effectively facilitate the Na-ion migration but also suppress the side reaction and inhibit the irreversible trapping of Na-ions in the crystal framework, leading to fast Na-ion diffusion kinetics. Moreover, the protonated titanate material experiences smaller changes in lattice parameters and unit-cell volume during long-term cycling than those of non-protonated material, resulting in less mechanical stresses and capacity loss in an anode. As expected, the protonated titanate material exhibits superior rate performance and ultralong lifespan when utilized as free-standing anode for SIB, remaining 85% capacity retention after 8000 cycles at 5.0Ag−1 (~ 23C). When assembled as full cell with Na3V2(PO4)3 cathode, high energy density (262.3Whkg−1) and power density (1748.9Wkg−1), excellent rate capability and superior cycle stability (260 cycles, 86%) can be achieved.