Global Environmental Issues Research Articles

Low-dimensional MXenes as noble metal-free co-catalyst for solar-to-fuel production: Progress and prospects

• Elaborate the fundamentals of solar-to-fuel production. • Summarize the synthetic strategies for 2D layered MXenes and 0D MXene QDs. • Generalize two themes like photocatalytic H 2 evolution and CO 2 reduction of MXenes. • Provide the prospects on the future directions in MXene photocatalysis. Direct conversion of solar energy into chemical fuels via semiconducting materials through photocatalytic technology is a sustainable way to tackle the global warming, environmental issue and energy crisis. Transition metal carbides and nitrides (MXenes), a newly emerging class of 2D layered materials, has gained tremendous attention as a noble metal-free co-catalyst for boosting photoreactivity due to its extraordinary characteristics like elemental abundance, excellent electrical conductivity, abundant surface functional groups, unique hydrophilic behavior and flexible modulation of chemical composition. The rational integration of low-dimensional MXenes in the form of 2D layered structures or 0D quantum dots with diverse semiconducting materials offer more versatile and robust heterostructured-photocatalysts that are applicable in solar fuel generation. Herein, we summarize the recent advances and achievements in the synthesis of low-dimensional MXenes and their application in hydrogen production from water splitting and CO 2 photoreduction. A comprehensive discussion of the fundamentals for solar fuel production, synthesis strategies and theoretical calculations for MXenes-based photocatalysts are also given. Finally, the existing challenges and further perspectives of MXenes-based nanostructures for efficient solar fuel production are addressed.

Microplastic pollution in sediments in the urban section of the Qara Su River, Iran

Microplastic pollution is an emerging threat to marine environments with potential environmental, social, economic, and health consequences and has become a major global environmental issue. The objective of the present study was to evaluate microplastic contamination in the ecosystem of the Qara Su River in Ardabil, Iran. Fifteen sampling sites along the Qara Su River in the Ardabil urban area were selected to collect sediment samples. The abundance and morphological characteristics of microplastics were determined by counting using a digital stereomicroscope. Micro-Fourier transform-infrared spectroscopy (μ-FTIR) analysis was used to identify polymer type of the microplastics. In this study, the frequency and distribution of microplastics (< 5 mm) in the sediment of Qara Su River were investigated as one of the sources containing microplastics. Sediment samples were collected from five different sites (Karkarq, Sar band, Anzab Sulfa, Dolat abad, and Samian) from September to March 2020. For microplastic examination in sediment, the amount (approximately 1000 g of fresh sediment from each site) was sampled from 15 sites. Fiber microplastics (53%) and fragments (33%) microplastics were predominant. It has shown the abundance and heterogeneity of space. In this study, the highest amount of microplastics detected in sediment samples was related to the size of less than 5000 µm (92%). The frequency of microplastics below 5000 µm in sediment was attributed to the low capacity of existing processes in Ardabil wastewater treatment plant. The abundance of microplastics shows significant differences between sampling sites. The Qara Su River along the city of Ardabil, like many other rivers, is contaminated with microplastics. This study was the first study conducted for evaluation of the sediment environment in terms of the microplastic pollution of Qara Su River in Ardabil. Considering the amount of microplastics in sediments, further research is required to estimate the amount of microplastics released by Ardabil wastewater treatment plants and industrial town wastewater, and other possible sources of emission and to evaluate their contribution to microplastic pollution in water, sediment, and soil. This study provided a framework for future studies of microplastics pollution in the sediment of urban areas around the Qara Su River in Iran.

CORE CONCEPT OF GLACIERS AND MELTING GLACIERS EFFECTING THE GLOBAL ENVIRONMENT

Glaciers and ice sheets are found almost in every continent of the world for more than thirty million years and are the large persistent body of perennial accumulation of dense crystalline snow and ice that exist intermittently over a period of time in Polar Regions and in the mountain ranges of landforms. Glaciers are constantly moving and melting because of internal and external pressure and gravity under its own weight. Although extensive glaciers systems lies on different mountain ranges of the landforms in the world i.e. more than seven thousand glaciers lies in Africa, Andes, Alaska, Canada, Greenland, Eurasia, European Alps, New Zeeland, Nepal, Norway, Pakistan, South America and in North America Continent. In the mountain landforms, Pakistan has more glacial ice in the Himalayan Range, Karakorum Range and Koh-Hindu-Kush Range. Glaciers also exist in southern hemisphere in Antarctic Region, in Northern Hemisphere in Arctic Region, Greenland and remaining occurs in the landforms of mountain regions. Glaciers exhibit the different wave like motions that mostly occur internally thus resulting the glacier surge, and waves of velocity. When the glaciers and ice sheet gains a large eroded material through the accumulation of snow above the equilibrium line, the glacier mass is lost through the ablation process and melting water runoff towards the down slope at lowest elevations below the equilibrium line that results the formation of accumulation area, alluvial fan stratification, alluvial plans, arête, askers, braided streams, cirques, crevasses, drumlins, fjords, fracture zones, glacial valleys, ice aprons, and ice bergs. Glaciers are among the oldest and coldest ecosystems on earth that together support the psychrophilic taxa and also impart a requisite water source to shape the downstream ecosystems. But due to global warming and rapid rise in the tropical climate change, melting of tropical glaciers, the fast ablation has contributed the shrinking of global glaciers thus causing the major biological, environmental and human consequences. Subsequently, mountain erosion results the transportation of debris, silt up, floods, and land sliding, raised the global environmental issues. The study includes the core concept of glaciers and melting glaciers effecting the global environments. Keywords: Askers, Craves, Drum line, Fjord, foliations, Gouge, Ice bergs.

Exploring the impact of air pollution on COVID-19 admitted cases

In urban areas, air pollution is one of the most serious global environmental issues. Using time-series approaches, this study looked into the validity of the relationship between air pollution and COVID-19 hospitalization. This time series research was carried out in the state of Kuwait; stationarity test, cointegration test, Granger causality and stability test, and test on multivariate time-series using the Vector Error Correction Model (VECM) technique. The findings reveal that the concentration rate of air pollutants (hbox {O}_3, hbox {SO}_2, hbox {NO}_2, hbox {CO}, and hbox {PM}_{10}) has an effect on COVID-19 admitted cases via Granger-cause. The Granger causation test shows that the concentration rate of air pollutants (hbox {O}_3, hbox {PM}_{10}, hbox {NO}_2, temperature and wind speed) influences and predicts the COVID-19 admitted cases. The findings suggest that sulfur dioxide (hbox {SO}_2), hbox {NO}_2, temperature, and wind speed induce an increase in COVID-19 admitted cases in the short term according to VECM analysis. The evidence of a positive long-run association between COVID-19 admitted cases and environmental air pollution might be shown in the cointegration test and the VECM. There is an affirmation that the usage of air pollutants (hbox {O}_3, hbox {SO}_2, hbox {NO}_2, hbox {CO}, and hbox {PM}_{10}) has a significant impact on COVID-19-admitted cases’ prediction and its explained about 24% of increasing COVID-19 admitted cases in Kuwait.

Approach to Development Sustainable Green City

Cities are centers of high natural resource utilization activities that contribute to the development of global environmental issues. Urban planning should be integrated with environmental planning in order to achieve sustainable development. This study aims to examine the position of the ecological urban concept in the concept of city ecology and sustainable cities. The method used in this study is a literature review of publications related to the concept of ecocity, urban ecology and sustainable city. The concept of green city development seeks to answer the issue of climate change through adaptation and mitigation actions, through attributes: green planning and design, green open space, green waste, green transportation, green water, green energy, green building, and green community.

Understanding the impact of changes in land-use land-cover and rainfall patterns on soil erosion rates using the RUSLE model and GIS techniques: A study on the Nagavali River basin

Abstract Soil erosion is the most common type of land degradation, and it has become a global environmental issue that reduces soil productivity and water quality and is accelerated by human-induced activities. The Revised Universal Soil Loss Equation (RUSLE) model, which includes factors like rainfall, soil, land-cover, cultivation practices, and slope, was incorporated into the Geographic Information System (GIS) database to estimate average annual soil erosion rates in the Nagavali River basin (NRB) during 1990 and 2020, and this study also focuses on analyzing the impact of the land-use and land-cover (LULC) change, as well as climate variability on the annual average soil erosion rates in the NRB. Results indicate that the average annual soil erosion rate in the NRB ranged from 0 to 2364.46 t/ha/yr in the year 1990 was increased to 7857.21 t/ha/yr by the year 2020 as a result of an increase in rainfall and LULC changes over the study period. Based on the spatial distribution of soil erosion risk classes, it was identified that the area under the very severe erosion class increased drastically from 4.34 to 13.97%, while the area under the very slight erosion class got decreased between the years 1990 and 2020. Accordingly, a correlation analysis was carried out to determine the spatial correlation between the soil erosion pattern and changes in driver variables such as rainfall and land-use classes. These findings can be used to make well-informed decisions at the local and regional levels for the sake of soil conservation.

Crosstalk and gene expression in microorganisms under metals stress.

Contamination of the environment with heavy metals (HMs) has led to huge global environmental issues. Industrialization activities such as mining, manufacturing, and construction generate massive amounts of toxic waste, posing environmental risks. HMs soil pollution causes a variety of environmental issues and has a detrimental effect on both animals and plants. To remove HMs from the soil, traditional physico-chemical techniques such as immobilization, electro-remediation, stabilization, and chemical reduction are used. Moreover, the high energy, trained manpower, and hazardous chemicals required by these methods make them expensive and non-environmentally friendly.Bioremediation process, which involves microorganism-based and microorganism-associated-plant-based approaches, is an ecologically sound and cost-effective strategy for restoring HMs polluted soil. Microbes adjust their physiology to these conditions to live, which can involve significant variations in the expression of the genes. A set of genes are activated in response to toxic metals in microbes. They can also adapt by modifying their shape, fruiting bodies creating biofilms, filaments, or chemotactically migrating away from stress chemicals. Microbes including Bacillus sp., Pseudomonas sp., and Aspergillus sp. has been found to have high metals remediation and tolerance capacity of up to 98% whether isolated or in combination with plants like Helianthus annuus, Trifolium repens, and Vallisneria denseserrulata. Several of the regulatory systems that have been discovered are unique, but there is also a lot of "cross-talk" among networks. This review discusses the current state of knowledge regarding themicrobial signaling responses, and the function of microbes in HMs stress resistance.

Immobilization of hexavalent chromium in soil-plant environment using calcium silicate hydrate synthesized from coal gangue

The presence of excessive hexavalent chromium (Cr(VI)) in the contaminated soils and plants has become a global environmental issue due to its toxicity and carcinogenicity. This work investigated the feasibility of immobilizing Cr(VI) in the soil-plant environment using calcium silicate hydrate (C–S–H) synthesized from coal gangue. The results revealed that the C–S–H amendment increased soil pH and organic matter (OM), which further promoted Cr(VI) immobilization. Results also revealed that exchangeable and carbonate bound fractions of Cr were either converted into Fe/Mn oxide and OM bound fractions of Cr or hardly released residual fraction of Cr due to C–S–H treatment. The C–S–H accelerated conversion of Cr(VI) into Cr(III) promoting plant growth and alleviating the toxic effect of Cr(VI). Cr(VI) was mainly immobilized and accumulated in the plant roots which resulted in comparatively lower Cr(VI) content in the edible part of plants. The exchangeable fraction of Cr in soil could be used as a bioavailability evaluation index of Cr(VI) in plants. In short, C–S–H was proved to be a practical and environmentally friendly amendment for in-situ immobilization of Cr(VI) contaminated soil.

Spatiotemporal Variation in Air Pollution Characteristics and Influencing Factors in Ulaanbaatar from 2016 to 2019

Ambient air pollution is a global environmental issue that affects human health. Ulaanbaatar (UB), the capital of Mongolia, is one of the most polluted cities in the world, and it is of great importance to study the temporal and spatial changes in air pollution in this city, along with their influencing factors. To understand the characteristics of atmospheric pollutants in UB, the contents of PM10, PM2.5, SO2, NO2, CO, and O3, as well as their influencing factors, were analyzed from data obtained from automatic air quality monitoring stations. These analyses yielded six major findings: (1) From 2016 to 2019, there was a total of 883 pollution days, and PM2.5 and PM10 were the primary pollutants on 553 and 351 of these days, respectively. The air pollution was dominated by PM10 in spring and summer, affected by both PM2.5 and PM10 in autumn, and dominated by PM2.5 in winter. (2) Compared with 2016, the number of days with good air quality in UB in 2019 increased by 45%, and the number of days with unhealthy or worse levels of pollution decreased by 56%, indicating that the air quality improved year by year. (3) From 2016 to 2019, the annual average PM2.5/PM10 ratio dropped from 0.55 to 0.45, and the proportion of PM2.5 in particulate matter decreased year by year. The PM concentration and PM2.5/PM10 ratio were highest in winter and lowest in summer. When comparing the four-season averages, the average PM2.5 concentration decreased by 89% from its highest level, and the PM10 concentration decreased by 67%, indicating stronger seasonal differences in PM2.5 than in PM10. (4) The hourly changes in PM concentration showed a bimodal pattern, exhibiting a decrease during the day and a slight increase in the afternoon due to temperature inversion, so the PM2.5/PM10 ratio increased at night in all four seasons. The PM concentration during the heating season was significantly higher than that in the non-heating season, indicating that coal-fired heating was the main cause of air pollution in UB. (5) Sand dust and soot were the two main types of pollution in UB. (6) Correlation analysis and linear fitting analysis showed that PM2.5 and PM10 caused by coal-firing had an important impact on air quality in UB. Coal combustion and vehicle emissions with SO2, NO2, and CO as factors made large contributions to PM2.5.

Enhancing Green Finance for Inclusive Green Growth: A Systematic Approach

Recently, green financing has become a popular technique for dealing with environmental issues. However, whether green financing is effective in addressing current global environmental issues remains to be seen since the green investment gap has been discovered to be rather sizable, with no certainty regarding how to fill it. The purpose of this study was to systematically analyze green finance in all of its forms, instruments, and measurements. Herein, we highlighted overall research trends in an effort to enhance green finance for inclusive green investment, as well as examined the progress needed to fill the green finance gap. This study also provides information on which authors, countries, publishers, and journals are contributing most to green finance. The methodological approach used in many reviewed papers was determined as a benchmark for those authors interested in green finance. Moreover, this study critically analyzes and summarizes 146 relevant studies. The results of our review study imply that the green financing gap is frequently observed because of low finance levels, poor green project selection/management, risk and return trade-off, and a lack of analytical tools and expertise in identifying and assessing green project risks. More specifically, regulatory issues have been observed as the main challenge in enhancing green finance. Therefore, we propose further studies to be conducted on how to enhance green finance for green investment that could deliberately affect green growth. Simultaneously, we noted what incentives could initiate private investors to make green investments, and what additional green financing methods should be introduced to fill the financing gap. Finally, this study seeks to have an impact in assisting future studies to consider the status of each country in terms of green finance mobilization and capital contribution by sharing the specific experience of that country and what lessons could be learned from that country.

Developing Countries in the Lead: A Bibliometric Approach to Green Finance

In recent years, green finance has become a popular method for dealing with environmental issues. However, it remains to be seen whether green financing is effective in addressing current global environmental issues. In this article, we, therefore, analyze the diffusion patterns of green finance publications in the Global South and Global North to identify which section of the globe is under-researched from this perspective. The study tried to highlight the overall trends of research publications on green finance, continent, most contributing authors, countries, and journals. The study used a bibliometric approach with the help of R studio software. The Scopus database was used for extracting the resources and 522 documents utilized in this bibliometric analysis. The result demonstrates that the diffusion of green finance is more common in the Global North than in the Global South. However, the number of scientific studies produced over time, the number of active authors, and affiliations of the Global South have contributed more than the Global North. More specifically, at the continental level, Asia and the Pacific are playing a lion’s share in providing scientific research publications on the green-finance-related issue. Meanwhile, the Arab states and Africa are the lowest contributing continent. China has the highest number of publications worldwide. However, this reality may be different if another approach (per capita contribution) is used to investigate the issue of green finance. Hence, we call for future studies to consider this fact in investigating the issue of green finance across the world. Furthermore, the study proposes further studies to be conducted on what are the factors that drive the Global South to lead. Finally, it is also better if the future studies take into account the status of each country in terms of green finance mobilization and capital contribution to share the specific experience of that country and lessons taken from that country.

Genomic analysis of Acinetobacter pittii CEP14 reveals its extensive biodegradation capabilities, including cometabolic degradation of cis-1,2-dichloroethene.

Halogenated organic compounds are naturally occurring in subsurface environments; however, accumulation of the degradative intermediate cis-1,2-dichloroethene (cDCE) at soil and groundwater sites contaminated with xenobiotic chlorinated ethenes is a global environmental and public health issue. Identifying microorganisms capable of cDCE degradation in these environments is of interest because of their potential application to bioremediation techniques. In this study, we sequenced, assembled, and analyzed the complete genome of Acinetobacter pittii CEP14, a strain isolated from chloroethene-contaminated groundwater, that has demonstrated the ability for aerobic cometabolic degradation of cDCE in the presence of n-hexane, phenol, and toluene. The A. pittii CEP14 genome consists of a 3.93Mbp-long chromosome (GenBank accession no. CP084921) with a GC content of 38.9% and three plasmids (GenBank accession no. CP084922, CP084923, and CP084924). Gene function was assigned to 83.4% of the 3,930 coding DNA sequences. Functional annotation of the genome revealed that the CEP14 strain possessed all genetic elements to mediate the degradation of a range of aliphatic and aromatic compounds, including n-hexane and phenol. In addition, it harbors gene clusters involved in cytosol detoxification and oxidative stress resistance, which could play a role in the mitigation of toxic chemical intermediates that can arise during the degradation of cDCE. Gene clusters for heavy metal and antibiotic resistance were also identified in the genome of CEP14. These results suggest that CEP14 may be a versatile degrader of xenobiotic compounds and well-adapted to polluted environments, where a combination of heavy metal and organic compound pollution is often found.

Perspectives of Implementing Agricultural Land Market in Ukraine within the Context of Reforms of Agrarian Sector

The relevance of the study comes from Ukraine being the largest agricultural country on the European continent by its size, with 41.5 million ha, and the second-largest arable land on the continent, mainly comprising humus-rich chernozems. Agriculture and agribusiness remain one of the driving forces of Ukraine’s economy, generating 15% of its GDP, employing 20% of the working population and accounting for 40% of the country’s exports. To support and bolster the agricultural sector, the state is developing and implementing reforms, the most significant of which is the introduction of a land market. In this context, Ukrainian agriculture has favourable conditions for development, but the exact effect of the implemented reforms remains unclear. The purpose of the study is to assess the state and trends in the development of agriculture in Ukraine in the context of ongoing reforms. The study employed the following methods: abstract-logical (through this method the main aspects of land reform and economic reform development strategy were identified), system analysis (the state of the Ukrainian economy was assessed), retrospective (the development of the agro-sector since Ukraine gained its independence was considered) and predictive (possible development scenarios were suggested). It was determined that it will take some time to manifest all the positive aspects of the reform, and its implementation involves a number of risks for small-scale farming. It became clear that climate changes also have an impact on agricultural productivity, and under its influence, some lands in Ukraine (e.g., the south) have already started to lose their value due to global environmental issues. The practical significance lies in determining the status and trends of agricultural development in the context of the structural reform of the national economy of Ukraine

Towards Green Driving: A Review of Efficient Driving Techniques

The exponential increase in the number of daily traveling vehicles has exacerbated global warming and environmental pollution issues. These problems directly threaten the continuity and quality of life on the planet. Several techniques and technologies have been used and developed to reduce fuel consumption and gas emissions of traveling vehicles over the road network. Here, we investigate some solutions that assist drivers to follow efficient driving tips during their trips. Advanced technologies of communications or vehicle manufacturing have enhanced traffic efficiency over road networks. In addition, several advisory systems have been proposed to recommend to drivers the most efficient speed, route, or other decisions to follow towards their targeted destinations. These recommendations are selected according to the real-time traffic distribution and the context of the road network. In this paper, different high fuel consumption scenarios are investigated over the road networks. Next, the details of efficient driving techniques that were proposed to tackle each case accordingly are reviewed and categorized for downtown and highway driving. Finally, a set of remarks and existing gaps are reported to researchers in this field.

Metabolome and transcriptome analyses of plants grown in naturally attenuated soil after hydrogen fluoride exposure

Accidental chemical leaks and illegal chemical discharges are a global environmental issue. In 2012, a hydrogen fluoride leak in Gumi, South Korea, killed several people and contaminated the environment. This leak also led to a significant decline in crop yield, even after the soil concentration of hydrogen fluoride decreased to below the standard level following natural attenuation. To determine the cause of this decreased plant productivity, we designed direct and indirect exposure tests by evaluating the metabolome, transcriptome, and phenome of the plants. In an indirect exposure test, soil metabolomics revealed downregulation of metabolites in vitamin B6, lipopolysaccharide, osmolyte, and exopolysaccharide metabolism. Next-generation sequencing of the plants showed that ABR1 and DREB1A were overexpressed in response to stress. Plant metabolomics demonstrated upregulation of folate biosynthesis and nicotinate and nicotinamide metabolism associated with detoxification of reactive oxygen species. These results demonstrate impaired metabolism of soil microbes and plants even after natural attenuation of hydrogen fluoride in soil. The novel chemical exposure testing used in this study can be applied to identify hidden damage to organisms after natural attenuation of chemicals in soil, as well as biomarkers for explaining the decline in yield of plants grown in soil near pollutant-emitting industrial facilities.

Metronidazole photocatalytic degradation by zinc oxide nanoparticles synthesized in watermelon peel extract; Advanced optimization, simulation and numerical models using machine learning applications

Antibiotics in water systems and wastewater are among the greatest major public health problem and it is global environmental issues. Herein a novel approach for the photocatalytic degradation of metronidazole (MTZ) by using eco-green zinc oxide nanoparticles (EG-ZnO NPs) which biosynthesised using watermelon peels extracts has been investigated. Mathematical prediction models using an adaptive neuro-fuzzy inference system (ANFIS), artificial neural networks (ANN) and response surface methodology (RSM) were used to determine the optimal conditions for the degradation process. The FESEM analysis revealed that EG-ZnO NPs was white with a spherical shape and size between 40 and 88 nm. The simulation process for the mathematical prediction model revealed that the best validation performance was 55.35 recorded at epoch 2, the coefficient (R2) was 0.9967 for training data, as detected using ANN analysis. The best operating parameters for MTZ degradation was predicted using RSM to be: 170 mg L−1 of EG-ZnO NPs, 20.61 mg 100 mL−1 of MTZ, 10 min exposure time, and a pH of 5, with 77.48 vs 78.14% corresponding to the predicted and empirically measured respectively. The photocatalytic degradation of MTZ was fitted with pseudo-first-order kinetic (R2 > 0.90). MTZ lost the antimicrobial activity against Bacillus cereus (B. cereus) and Escherichia coli (E. coli) after degradation with EG-ZnO NPs at the optimal conditions as determined in the optimization process. These findings reflect the important role ANFIS and ANN in predicting and optimising the efficacy of engineered nanomaterials, including EG-ZnO NPs, for antibiotic degradation.

Single‐Atom Catalysts for Hydrogen Generation: Rational Design, Recent Advances, and Perspectives

AbstractHydrogen is widely believed to be a promising fuel to solve the global energy crisis and environmental issues. The catalytic system represented by metal‐supported catalysts is an important process of upgrading the hydrogen source in industry. Single‐atom catalysts (SACs), which inherit the advantages of homogeneous and heterogeneous catalysts, provide a broad prospect for low‐cost H2 production technology. This review focuses on the potential mechanisms in the rational design of SACs, including active sites, coordination configuration, mass loading, heteroatom‐doping, and metal−support interaction. The design strategies of single metal atoms on different supports are reviewed to give a proposal on how to immobilize the atomic active sites and modulate the geometric/electronic structures of SACs. Subsequently, the synergistic effect in SACs and the dynamic evolution of the atomically dispersed heterometal catalysts are introduced, aiming to provide further guidelines for H2 evolution SACs. H2 generation from the water−gas shift reaction and electro‐/photocatalytic water splitting are the main research directions at present. The latest progress of SACs employed in these applications is thoroughly reviewed. At the end of this review, personal perspectives on the prospects and challenges of H2 evolution SACs are put forward, hoping to promote the rapid development of SACs toward superior H2 evolution performance.

Forest Habitat Fragmentation in Mountain Protected Areas Using Historical Corona KH-9 and Sentinel-2 Satellite Imagery

Forest habitat fragmentation is one of the global environmental issues of concern as a result of forest management practices and socioeconomic drivers. In this context, a constant evaluation of natural habitat conditions still remains a challenge in order to achieve a general image of the environmental state of a protected area for proper sustainable management. The purpose of our study was to evaluate the evolution of forest habitat in the last 40 years, focusing on Bucegi Natural Park, one of the most frequented protected areas in Romania, as relevant for highly human-impacted areas. Our approach integrates a historical panchromatic Corona KH-9 image from 1977 and present-day Sentinel-2 multispectral data from 2020 in order to calculate a series of spatial metrics that reveal changes in the pattern of the forest habitat and illustrate forest habitat fragmentation density. Object-based oriented analysis with supervised maximum likelihood classification was employed for the production of forest cover fragmentation maps. Ten landscape metrics were adapted to the analysis context, from patch statistics to proximity index. The results show a general growth of the forest surface but also an increase in habitat fragmentation in areas where tourism was developed. Fragmentation indices explain that larger and compact patches feature natural park protected forests after the spruce–fir secondary canopies were grown during the last 4–5 decades. The number of patches decreased to half, and their average size is double that of before. The method can be of extensive use for environmental monitoring in protected areas management and for understanding the environmental history connected to present-day problems that are to be fixed under rising human pressure.

Evaluation of Indirect-Heated Microwave Thermal Desorption Treatment on Engineering Properties of Lubricant-Contaminated Soil

Soil pollution caused by oil leakage from various industrial facilities such as gas stations, oil plants, military bases, and railway depots has become a serious global environmental and geotechnical issue. The indirect-heated microwave thermal desorption technology has been developed in this study for economical and efficient remediation of oil or organic pollutants. The conclusions were made based on laboratory tests and analyses of the environmental (TPH; total petroleum hydrocarbons) and geotechnical (physical and mechanical) properties of the soil before and after treatments. (1) As the newly-developed equipment was operated for 3 h with the electric power of 32 kW to reach target temperature of 600 °C, more than 99.8% of TPH was removed. (2) In the aspect of geotechnical properties, the internal friction angle, maximum dry density and permeability coefficient of the soil were reduced by oil contamination and were finally restored to the almost initial level of the soil after treatment. Therefore, treated soil is expected to be reusable for geotechnical construction purposes such as construction fill materials. (3) It was also found that the developed technology reduces 75% of energy cost and 25% of CO2 emissions for the remediation of lubricant oil-contaminated soil comparing with conventional one.

A review on distributed generation impacts on electric power system

In 2021, the world's total installed capacity of generation units based on renewable energy sources (not including hydropower) amounted to about 1674 GW: over 825 GW and 849 GW of wind and solar power plants were installed respectively. The growing of the installed capacity of these distributed generators is a response to the increasing the power consumption, global environmental issues and has also become possible due to the development of technology in field of power semiconductor devices. However, on the way of large-scale implementation of distributed generators based on renewable energy sources, traditional electric power system meets new challenges to ensure the reliability and sustainability of new electric power systems with renewable energy sources. In particular, distributed generators change processes in the electric power system, impact to the parameters and power balance, change the magnitude and direction of power flow and short-circuit current, which determines the need to update the settings of the relay protection and automation systems of traditional electric power system and to coordinate their operation with automatic control systems of installed distributed generators. The above-mentioned tasks form a number of scientific research directions, one of which is a task of determining optimal size and location of distributed generators. The main purpose of this optimization task is to reduce power losses, operating and total electricity cost, improve the voltage profile, etc. In addition, the correct and reasonable placement of distributed generators defines an effective planning of the operating modes of electric power system and power plants (especially based on renewable energy sources, the operating modes of which depend on weather conditions and can be sharply variable).The paper highlighted the impacts of distributed generators on power losses, the voltage level, maintaining the power balance and the possibility of participating in the frequency regulation, and short-circuit current in power system. The optimization criteria, the main limiting conditions, as well as methods for solving this optimization problem are considered. This review will help the System operators and investing companies, especially in Russia, to form the main aim, objective function and constraints that will aid to meet their load demand at minimum cost and to choose from the options available for optimization of location and capacity of distributed generators.