Heat island phenomenon rises the temperature of cities, increases the energy demand for cooling and deteriorates comfort conditions in the urban environment. To counterbalance the impact of the ...phenomenon, important mitigation techniques have been proposed and developed. Pavements present a very high fraction of the urban areas and contribute highly to the development of heat island in cities. The use of cool pavements presenting substantially lower surface temperature and reduced sensible heat flux to the atmosphere, appears to be one of the most important proposed mitigation solutions. The present paper investigates and describes the actual state of the art on the field of cool pavements. The main thermal and optical parameters defining the thermal performance of pavements are analyzed. Almost all of the developed technologies, where data and results are available, are considered while emphasis is given on the presentation of reflective and permeable/water retentive pavements. The main technological achievements on both fields are reviewed while existing applications are described and performance data are given when available. The existing results clearly show that the mitigation and cooling potential of cool pavements is very significant and can highly contribute to decrease temperature on the urban environment.
Global warming is now the most serious environmental challenge. In the most recent Paris accord, authorities opted to reduce global emissions to a certain level and voiced significant concern for ...China, the world's largest CO2 emitter, accounting for around 29.4% of total emissions. In contrast, coal accounts 65% of the majority of China's energy mix in 2019. Therefore, it is critical to analyze the environmental factors influencing China's CO2 emissions. Hence, the research examines fossil fuel energy, renewable energy, and GDP between 1980 to 2018 using novel dynamic ARDL simulations and Frequency Domain Causality (FDC) models. The empirical findings show that fossil fuel energy intensely boosts CO2 emissions long and short term. On the other hand, GDP increases carbon emissions in the long term but has a significant adverse effect on China's environment in the short run. While renewable energy usage has a short-term detrimental impact on CO2 emissions. The FDC also supports the long-, medium-and short-term causality hypotheses. Overall, our results imply that renewable energy consumption is crucial for achieving sustainable environmental goals and discourages fossil fuel use in the energy mix. We recommend that China consider empirical evidence and initiate long-term strategies to diminish carbon emissions for a sustainable environment.
Considering the environment protection, “green” materials are increasingly explored for photovoltaics. Here, we developed a kind of quantum dots solar cell based on nitrogen-doped carbon dots. The ...nitrogen-doped carbon dots were prepared by direct pyrolysis of citric acid and ammonia. The nitrogen-doped carbon dots’ excitonic absorption depends on the N-doping content in the carbon dots. The N-doping can be readily modified by the mass ratio of reactants. The constructed “green” nitrogen-doped carbon dots solar cell achieves the best power conversion efficiency of 0.79 % under AM 1.5 G one full sun illumination, which is the highest efficiency for carbon dot-based solar cells.
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Two-dimensional materials including TMDCs, hBN, graphene, non-layered compounds, black phosphorous, Xenes and other emerging materials with large lateral dimensions exceeding a hundred ...micrometres are summarised detailing their synthetic strategies.
Crystal quality optimisations and defect engineering are discussed for large-area two-dimensional materials synthesis.
Electronics and optoelectronics applications enabled by large-area two-dimensional materials are explored.
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Large-area and high-quality two-dimensional crystals are the basis for the development of the next-generation electronic and optical devices. The synthesis of two-dimensional materials in wafer scales is the first critical step for future technology uptake by the industries; however, currently presented as a significant challenge. Substantial efforts have been devoted to producing atomically thin two-dimensional materials with large lateral dimensions, controllable and uniform thicknesses, large crystal domains and minimum defects. In this review, recent advances in synthetic routes to obtain high-quality two-dimensional crystals with lateral sizes exceeding a hundred micrometres are outlined. Applications of the achieved large-area two-dimensional crystals in electronics and optoelectronics are summarised, and advantages and disadvantages of each approach considering ease of the synthesis, defects, grain sizes and uniformity are discussed.
Graphite carbon nitride (g-C
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) is well known as one of the most promising materials for photocatalytic activities, such as CO
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reduction and water splitting, and environmental remediation ...through the removal of organic pollutants. On the other hand, carbon nitride also pose outstanding properties and extensive application forecasts in the aspect of field emission properties. In this mini review, the novel structure, synthesis and preparation techniques of full-bodied g-C
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-based composite and films were revealed. This mini review discussed contemporary advancement in the structure, synthesis, and diverse methods used for preparing g-C
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nanostructured materials. The present study gives an account of full knowledge of the use of the exceptional structural and properties, and the preparation techniques of graphite carbon nitride (g-C
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) and its applications.
•The impact of urbanization on the coupling between economy and environment is non-linear.•The traditional EKC theory is extended by adding the social indicator.•Threshold regression model is applied ...to investigate the non-linear causality.•Comparatively analyzes the threshold regression results of four income groups.•Urbanization does not help reduce environmental pressures.
The purpose of this article is to explore the impact of urbanization on the coupling of economic growth and environmental quality. The traditional environmental Kuznets curve (EKC) hypothesis explains the inverted U-shaped relationship between the economy and the environment. This study expands the traditional EKC theory by adding social indicator, which also corresponds to the three aspects (social, economic, and environmental) required for sustainable development in 2030. Based on the panel data of 134 countries from 1996 to 2015, the threshold regression model is applied to investigate the non-linear causality between the variables. The threshold variable is urbanization, and the impact mechanism of economic growth on carbon dioxide emissions and ecological footprint is tested. The results show that: urbanization strengthens the positive correlation between the economy and carbon emissions and ecological footprint. The positive effect of economic growth on the ecological footprint is greater than that of carbon emissions. Trade openness and natural resource rents increase environmental pressure. Population aging and renewable energy improve the quality of the environment. There is heterogeneity in the values and change trend of the regression coefficients of different income groups. Unlike the coefficient growth trend in the results of all countries, the following situations occur. As urbanization successively crosses the threshold, the positive effect of economic growth on carbon dioxide emissions in high income countries diminishes. The coefficient of the lower middle income group has an inverted U-shape. When the ecological footprint is the explained variable, the coefficient of the high income group becomes U-shaped.
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COVID-19 caused significant challenges for small and medium-sized enterprises (SMEs) in the event industry. To address these challenges, many SMEs leveraged information and communication technologies ...(ICTs), with some even emerging strengthened from the crisis. Drawing on the technology-organization-environment framework and technology-affordances-and-constraints theory, we investigate the adoption of ICTs as a crisis response strategy in 10 SMEs in the German business event (e.g., corporate events, conferences) industry. Our findings reveal that ICT adoption not only depends on rational decisions based on organizational, environmental, and technological characteristics, but also on these dimensions' interrelationship and the specific ICTs' affordances and constraints. Introducing readily available ICTs (e.g., video-conferencing) has significant potential in addressing physical distancing in the short and medium term, while more sophisticated ICTs (e.g., virtual reality) are more likely to gain importance in the long term. Thus, we expand our understanding of organizational technology adoption and ICT-enabled crisis response strategies in SMEs.
Separation and sorting of micron-sized particles has great importance in diagnostics, chemical and biological analyses, food and chemical processing and environmental assessment. By employing the ...unique characteristics of microscale flow phenomena, various techniques have been established for fast and accurate separation and sorting of microparticles in a continuous manner. The advancements in microfluidics enable sorting technologies that combine the benefits of continuous operation with small-sized scale suitable for manipulation and probing of individual particles or cells. Microfluidic sorting platforms require smaller sample volume, which has several benefits in terms of reduced cost of reagents, analysis time and less invasiveness to patients for sample extraction. Additionally, smaller size of device together with lower fabrication cost allows massive parallelization, which makes high-throughput sorting possible. Both passive and active separation and sorting techniques have been reported in literature. Passive techniques utilize the interaction between particles, flow field and the channel structure and do not require external fields. On the other hand, active techniques make use of external fields in various forms but offer better performance. This paper provides an extensive review of various passive and active separation techniques including basic theories and experimental details. The working principles are explained in detail, and performances of the devices are discussed.
Light Detection and Ranging (LiDAR) technology has been widely used in forestry surveys in the form of airborne laser scanning (ALS), terrestrial laser scanning (TLS), and mobile laser scanning ...(MLS). The acquisition of important basic tree parameters (e.g., diameter at breast height and tree position) in forest inventory did not solve the problem of low measurement efficiency or weak GNSS signal under the canopy. A personal laser scanning (PLS) device combined with SLAM technology provides an effective solution for forest inventory under complex conditions with its light weight and flexible mobility. This study proposes a new method for calculating the volume of a cylinder using point cloud data obtained by a PLS device by fitting to a polygonal cylinder to calculate the diameter of the trunk. The point cloud data of tree trunks of different thickness were modeled using different fitting methods. The rate of correct tree trunk detection was 93.3% and the total deviation of the estimations of tree diameter at breast height (DBH) was -1.26 cm. The root mean square errors (RMSEs) of the estimations of the extracted DBH and the tree position were 1.58 cm and 26 cm, respectively. The survey efficiency of the personal laser scanning (PLS) device was 30m2/min for each investigator, compared with 0.91m2/min for the field survey. The test demonstrated that the PLS device combined with the SLAM algorithm provides an efficient and convenient solution for forest inventory.
Deterministic lateral displacement (DLD) pillar arrays are an efficient technology to sort, separate and enrich micrometre-scale particles, which include parasites, bacteria, blood cells and ...circulating tumour cells in blood. However, this technology has not been translated to the true nanoscale, where it could function on biocolloids, such as exosomes. Exosomes, a key target of 'liquid biopsies', are secreted by cells and contain nucleic acid and protein information about their originating tissue. One challenge in the study of exosome biology is to sort exosomes by size and surface markers. We use manufacturable silicon processes to produce nanoscale DLD (nano-DLD) arrays of uniform gap sizes ranging from 25 to 235 nm. We show that at low Péclet (Pe) numbers, at which diffusion and deterministic displacement compete, nano-DLD arrays separate particles between 20 to 110 nm based on size with sharp resolution. Further, we demonstrate the size-based displacement of exosomes, and so open up the potential for on-chip sorting and quantification of these important biocolloids.
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