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Search Results (55,210)

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19 pages, 15489 KiB  
Article
‘Sharing’ as a Critical Framework for Waterfront Heritage Regeneration: A Case Study of Suzhou Creek, Shanghai
by Yichen Zhu and Zhenyu Li
Land 2024, 13(8), 1280; https://doi.org/10.3390/land13081280 - 13 Aug 2024
Abstract
The purpose of this study was to analyze ‘sharing’ as an operational framework for waterfront industrial heritage revitalization in the context of sustainable urban regeneration. This research study was conducted to better understand the public accessibility of heritage preservation projects in a densely [...] Read more.
The purpose of this study was to analyze ‘sharing’ as an operational framework for waterfront industrial heritage revitalization in the context of sustainable urban regeneration. This research study was conducted to better understand the public accessibility of heritage preservation projects in a densely populated waterfront urban area and to determine to what extent heritage could be made available to the general public. We examined the development of industrial heritage along Suzhou Creek, Shanghai, and its process of regeneration. The focus area covered a waterway stretch of 19.2 km and an adjacent land area of 11.7 km2 managed as a single planning entity on both sides of the creek. We analyzed the present preservation practices and discovered a growing desire to increase the historical buildings’ visibility in the context of urban regeneration. We argue that ‘sharing’ can serve as a pivotal framework for sustainable waterfront regeneration, as its implementation can (1) increase the public value of waterfront heritage and (2) incorporate comprehensive objectives, design strategies, evaluation methods, and public participation into the space revitalization process. Full article
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<p>Planning area of the One River One Creek Masterplan of Shanghai 2035. Source: edited by the authors based on the Shanghai 2035 plan.</p>
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<p>Images of Suzhou Creek in the past and now. Source: the left image, representing Suzhou Creek in the 1940s, was taken from Pengpai News, while the image on the right was taken by the authors in 2023.</p>
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<p>Field study area and locations of industrial heritage sites along Suzhou Creek. Source: Authors.</p>
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<p>The 65 industrial heritage sites of this case study. Source: Authors.</p>
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<p>The urban morphology and architectural typology analysis of the WIH buildings along Suzhou Creek. Source: Authors.</p>
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<p>The accessibility of the 65 industrial heritage sites of this case study. Source: Authors.</p>
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<p>‘Sharing’ framework for WIH revitalization. Source: Authors.</p>
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<p>Node–path–area spatial relationships of WIH sites along Suzhou Creek. Source: Authors.</p>
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<p>The Star Model for WIH shareability evaluation. Source: Authors.</p>
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<p>Application of the ‘sharing’ module in design and planning management. Source: Authors.</p>
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16 pages, 4169 KiB  
Article
Assessing the Impact of Anthropogenically Modified Land Uses on Wetland Health: Case of Witbank Dam Catchment in South Africa
by Sylvester Mpandeli, Stanley Liphadzi, Chengetanai Mabhaudhi, Tafadzwanashe Mabhaudhi and Luxon Nhamo
Water 2024, 16(16), 2287; https://doi.org/10.3390/w16162287 - 13 Aug 2024
Abstract
Wetlands are critical ecological infrastructures that improve water quality, serve as habitat for fish and other aquatic life, accumulate floodwaters, and maintain surface water flow during dry periods. However, the health of wetlands has been compromised by anthropogenic activities that affect the constant [...] Read more.
Wetlands are critical ecological infrastructures that improve water quality, serve as habitat for fish and other aquatic life, accumulate floodwaters, and maintain surface water flow during dry periods. However, the health of wetlands has been compromised by anthropogenic activities that affect the constant supply of ecosystem services. This study assessed the impact of anthropogenically modified land use on wetland health in the Witbank Dam Catchment in South Africa, whose land use has been severely modified for agriculture and mining purposes. The study developed a model linking surface runoff generated in the catchment with land use and wetland typology to comprehend diffuse pollution from pollution-source land uses. Runoff data and related wetland spatial information were processed and analysed in a Geographic Information System (GIS) to estimate pollutants (agricultural nutrients and acid mine drainage) from runoff detained and released by wetlands. The analysis facilitated the assessment of the value of wetlands in enhancing water quality, as well as human and environmental health. The runoff volume from pollution-source land uses (urban areas, farmlands, and mining) was used to evaluate annual pollution levels. Wetland types are ranked according to their efficiency levels to filter pollutants. The assumption is that the difference between filtered and unfiltered runoff is the quantity of polluted runoff water discharged into the river system. The analysis has shown that 85% of polluted runoff generated in the catchment ends up in the river system. An important observation is that although wetlands have a substantial ability to absorb excess pollutants, they have finite boundaries. Once they reach their full holding capacity, they can no longer absorb any further pollutants. The excess is discharged into the river system, risking human and environmental health. This explains why the Limpopo River is heavily polluted resulting in the death of fish, crocodiles and other aquatic life. Full article
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<p>Location, elevation, and wetland types of the Witbank Dam Catchment. Source: Van Devente et al., 2020 [<a href="#B54-water-16-02287" class="html-bibr">54</a>].</p>
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<p>Land use/cover of the Witbank Dam Catchment.</p>
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<p>An illustration of how the flow accumulation tool works. The tool was used to constrain and determine the exact runoff that discharges into a wetland.</p>
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<p>Abundance and typology of wetlands in the Quaternary Basins of the Witbank Dam Catchment.</p>
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19 pages, 6216 KiB  
Article
Monitoring the Soil Copper of Urban Land with Visible and Near-Infrared Spectroscopy: Comparing Spectral, Compositional, and Spatial Similarities
by Yi Liu, Tiezhu Shi, Yiyun Chen, Zeying Lan, Kai Guo, Dachang Zhuang, Chao Yang and Wenyi Zhang
Land 2024, 13(8), 1279; https://doi.org/10.3390/land13081279 - 13 Aug 2024
Abstract
Heavy metal contamination in urban land has become a serious environmental problem in large cities. Visible and near-infrared spectroscopy (vis-NIR) has emerged as a promising method for monitoring copper (Cu), which is one of the heavy metals. When using vis-NIR spectroscopy, it is [...] Read more.
Heavy metal contamination in urban land has become a serious environmental problem in large cities. Visible and near-infrared spectroscopy (vis-NIR) has emerged as a promising method for monitoring copper (Cu), which is one of the heavy metals. When using vis-NIR spectroscopy, it is crucial to consider sample similarity. However, there is limited research on studying sample similarities and determining their relative importance. In this study, we compared three types of similarities: spectral, compositional, and spatial similarities. We collected 250 topsoil samples (0–20 cm) from Shenzhen City in southwest China and analyzed their vis-NIR spectroscopy data (350–2500 nm). For each type of similarity, we divided the samples into five groups and constructed Cu measurement models. The results showed that compositional similarity exhibited the best performance (Rp2 = 0.92, RPD = 3.57) and significantly outperformed the other two types of similarity. Spatial similarity (Rp2 = 0.73, RPD = 1.88) performed slightly better than spectral similarity (Rp2 = 0.71, RPD = 1.85). Therefore, we concluded that the ranking of the Cu measurement model’s performance was as follows: compositional similarity > spatial similarity > spectral similarity. Furthermore, it is challenging to maintain high levels of similarity across all three aspects simultaneously. Full article
(This article belongs to the Special Issue Land Degradation and Soil Mapping)
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<p>Map showing the positions of the sampling sites and the landscape, as indicated by a Landsat 8 OLI image with a composition of band 4 (red), 3 (green), and 2 (blue).</p>
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<p>Dividing samples into five groups based on spectral similarity. Group 1 has the highest reflectance, while Group 5 has the lowest. Reflectance gradually decreases from Group 1 to Group 5.</p>
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<p>Dividing the samples into five groups based on compositional similarity. Group 1 has the lowest Cu content, while Group 5 has the highest. The Cu content gradually increases from Group 1 to Group 5.</p>
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<p>Dividing the samples into five groups based on spatial similarity. Each group contains samples that are geographically close to each other. Each group covers a distinct area, clearly different from the areas covered by other groups.</p>
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<p>Comparison of soil Cu content between predicted and measured values using spectroscopy models without considering similarity. RMSEP denotes the root mean square error of prediction. <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mi>R</mi> </mrow> <mrow> <mi>p</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msubsup> </mrow> </semantics></math> denotes the coefficient of determination in prediction. RPD denotes the residual predictive deviation.</p>
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<p>Performance of soil Cu measurement model when considering spectral similarity.</p>
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<p>Performance of the soil Cu measurement model when considering compositional similarity.</p>
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<p>Performance of the soil Cu measurement model when considering spatial similarity.</p>
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<p>Comparison of soil Cu content between predicted and measured values using spectroscopy models when considering spectral similarity (<b>a</b>), compositional similarity (<b>b</b>), and spatial similarity (<b>c</b>). RMSEP denotes the root mean square error of prediction. <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mi>R</mi> </mrow> <mrow> <mi>p</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msubsup> </mrow> </semantics></math> denotes the coefficient of determination in prediction. RPD denotes the residual predictive deviation.</p>
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<p>Comparison of spectral similarity (<b>a</b>–<b>c</b>), compositional similarity (<b>d</b>–<b>f</b>), and spatial similarity (<b>g</b>–<b>i</b>).</p>
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<p>Variable importance projection (VIP) scores associated with the cross-validation of the partial least-squares regression model for soil Cu measurement. The threshold of VIP was set to 1 (red line).</p>
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18 pages, 1031 KiB  
Article
Chemical Characterization of Cider Produced in Hardanger—From Juice to Finished Cider
by Ingunn Øvsthus, Mitja Martelanc, Alen Albreht, Tatjana Radovanović Vukajlović, Urban Česnik and Branka Mozetič Vodopivec
Beverages 2024, 10(3), 73; https://doi.org/10.3390/beverages10030073 - 13 Aug 2024
Abstract
Our investigation delves into the previously uncharted territory of cider composition from Norway. This study aimed to obtain an overview of the qualitative and quantitative compositions of general chemical parameters, polyphenols (individual and total expressed as gallic acids equivalents), selected esters, and selected [...] Read more.
Our investigation delves into the previously uncharted territory of cider composition from Norway. This study aimed to obtain an overview of the qualitative and quantitative compositions of general chemical parameters, polyphenols (individual and total expressed as gallic acids equivalents), selected esters, and selected C6-alcohols in ciders with the PDO label Cider from Hardanger. In total, 45 juice and cider samples from the fermentation process were collected from 10 cider producers in Hardanger in 2019, 2020, and 2021. Individual sugars, acids, ethanol, and 13 individual phenols were quantified using HPLC-UV/RI. Seven ethyl esters of fatty acids, four ethyl esters of branched fatty acids, ten acetate esters, two ethyl esters of hydroxycinnamic acids, and four C6-alcohols were quantified using HS-SPME-GC-MS. For samples of single cultivars (‘Aroma’, ‘Discovery’, ‘Gravenstein’, and ‘Summerred’), the sum of the measured individual polyphenols in the samples ranges, on average, from 79 to 289 mg L−1 (the lowest for ‘Summerred’ and highest for ‘Discovery’ and ‘Gravenstein’). Chlorogenic acid was the most abundant polyphenol in all samples. Ethyl butyrate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, ethyl isobutyrate, ethyl 2-methylbutyrate, isoamyl acetate, and hexanol were present at concentrations above the odour threshold and contributed to the fruity flavour of the Cider from Hardanger. Full article
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<p>Principal component analysis loading plot (<b>A</b>) and score plot for cultivars (<b>B</b>) for measured esters and C6-alcohols in the collected samples in 2019, 2020, and 2021 for ciders. Aroma compounds in bold letters are in concentrations over the threshold limit.</p>
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25 pages, 21885 KiB  
Article
A Clustering Approach for Analyzing Access to Public Transportation and Destinations
by Mudassar Shafiq, Hudyeron Rocha, António Couto and Sara Ferreira
Sustainability 2024, 16(16), 6944; https://doi.org/10.3390/su16166944 - 13 Aug 2024
Abstract
Promoting sustainable and equitable public transportation services is essential for addressing disparities and preventing social exclusion among diverse population groups for daily activities. This paper proposes a comprehensive approach to assess transport disadvantages and identify areas with limited access to public transport and [...] Read more.
Promoting sustainable and equitable public transportation services is essential for addressing disparities and preventing social exclusion among diverse population groups for daily activities. This paper proposes a comprehensive approach to assess transport disadvantages and identify areas with limited access to public transport and services. By combining statistical and geographic techniques, we analyze demographic, socioeconomic, and travel data to spatially contextualize areas based on the social structure and understand the characteristics of population groups facing transportation challenges in the Porto Metropolitan Area. Cluster analysis results revealed four distinct clusters with homogeneous characteristics. In contrast, service area analysis assessed the public transport coverage to identify served zones, the population within these zones, and activities reached in the region. Our findings indicate that suburban and rural areas often lack access to public transport stops, aggravated by lower service frequencies, leading to high reliance on private cars for essential activities, such as work and education. Despite the good geographical coverage of rail and bus stops, urban and central–urban areas also suffer from inadequate service frequencies, impacting public transport usage. Improving service quality in high-demand areas could encourage greater public transport utilization and enhance accessibility. Identifying areas facing inequities facilitates targeted policy interventions and prioritized investments to improve accessibility and address mobility needs to access services effectively. Full article
(This article belongs to the Special Issue Sustainable Urban Transport Planning)
22 pages, 17197 KiB  
Article
Relocating the Urban Center: Lessons of Vilnius
by Agnė Gabrėnienė, Arnoldas Gabrėnas and Almantas Liudas Samalavičius
Urban Sci. 2024, 8(3), 112; https://doi.org/10.3390/urbansci8030112 - 13 Aug 2024
Abstract
The article analyzes the recent relocation of the city center to another semi-central area, formerly a historical suburb of Šnipiškės in Vilnius, Lithuania, which took place in the context of post-Soviet transformations. This article is a continuation of the authors’ work in researching [...] Read more.
The article analyzes the recent relocation of the city center to another semi-central area, formerly a historical suburb of Šnipiškės in Vilnius, Lithuania, which took place in the context of post-Soviet transformations. This article is a continuation of the authors’ work in researching the Šnipiškės territory, where the authors emphasize that an ambitious political decision, poorly supported by data and based on a questionable vision, was not successful. This study employs a concept-driven, qualitative approach to analyze the urban transformation of the territory. Grounded in architectural theories, the research examines how relocating the city center to this historic suburb has impacted its character. The findings highlight the challenges encountered and derive lessons for similar post-Soviet and post-colonial urban transformations. Full article
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<p>Historical center of Vilnius (UNESCO) and its buffer zone.</p>
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<p>Scheme of the Šnipiškės ward and its nearest surroundings.</p>
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<p>Šnipiškių Street (old Ukmergės Road) and the Swedbank building.</p>
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<p>A military parade on Konstitucijos Avenue.</p>
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<p>Scheme of public spaces in the CBD (“A”—the square beside the National Art Gallery, “B”—the wooden Swedbank terrace, and “C”—the pedestrian route from Šnipiškės to the Old Town).</p>
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<p>Public spaces in Šnipiškės. Left to right: (<b>A</b>)—the square beside the National Art Gallery, (<b>B</b>)—the wooden Swedbank terrace, and (<b>C</b>)—the pedestrian route from Šnipiškės to the Old Town.</p>
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<p>Buildings illustrating locations of respective typological groups in the Giedraičiai sub-ward.</p>
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<p>Wooden buildings in Šnipiškės. Left to right: 7 and 10 Giedraičių Street (urban houses); 47b, 39, and 65 Krokuvos Street (rural houses); 14 Giedraičių Street (urban house).</p>
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<p>Masonry buildings in Šnipiškės. Left to right: 56 and 67 Krokuvos Street and 9 Linkmenų Street.</p>
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<p>New buildings in Šnipiškės. Left to right: 15 and 18b Konstitucijos Avenue and 37 Lvovo Street.</p>
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<p>Swedbank building with the 4500 m<sup>2</sup> wooden terrace on the roof.</p>
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<p>Apartment buildings at 11 Daugėliškio St. 11, 60 Krokuvos St. 60, and 17 Kernavės St. 17.</p>
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<p>The “efforts to update tradition in the new residential architecture of Šnipiškės. From left to right: building with restored original masonry wall at 7 Šatrijos Street, the multi-story residential building at 3 Kintų Street, and the “Namai—Kintai” project”.</p>
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23 pages, 1986 KiB  
Article
Forest Products Trade-Environment Nexus through the Lens of Carbon Neutrality Targets: The Role of Rural Bioenergy
by Li Mi, Yongjun Huang and Muhammad Tayyab Sohail
Forests 2024, 15(8), 1421; https://doi.org/10.3390/f15081421 - 13 Aug 2024
Abstract
Environmental sustainability is the primary objective of policymakers all around the globe. The most viable option to deal with this situation is to increase the use of renewable energy sources, particularly bioenergy, a carbon-neutral energy source. Trading activities in clean and green products [...] Read more.
Environmental sustainability is the primary objective of policymakers all around the globe. The most viable option to deal with this situation is to increase the use of renewable energy sources, particularly bioenergy, a carbon-neutral energy source. Trading activities in clean and green products can also enhance environmental performance. The literature on the impact of bioenergy and trade in environmental goods on ecological sustainability is growing. However, the empirical literature has not shed light on the impact of forest products trade (FPT) and rural bioenergy on environmental sustainability, leaving a significant gap in the literature. To address this gap, this analysis examines the impact of FPT and rural bioenergy on environmental sustainability using 23 economies from 2000 to 2022. Empirical estimates of the model are obtained by applying several estimation techniques, such as fixed effects (FE), random effects (RE), two-stage least squares (2SLS), generalized method of moments (GMM), and cross-sectional autoregressive distributed lag (CS-ARDL). The findings confirm that FPT and rural bioenergy reduce CO2 emissions and contribute to environmental sustainability. The estimates of control variables of economic growth, industrialization, technological development, urbanization, and financial development are positively significant, confirming that these factors increase carbon footprints and thus hurt environmental sustainability. In contrast, political stability negatively impacts carbon emissions and thus promotes environmental sustainability. In light of these findings, policymakers should encourage forest products trade and rural bioenergy to achieve environmental sustainability. Full article
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<p>CO<sub>2</sub> emissions, forest products trade, and biofuel production, global trends.</p>
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<p>Trend of forest products trade (USD 1000) by region.</p>
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<p>Trend of biofuel production (TWh) by region.</p>
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<p>Analysis flowcharts.</p>
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<p>Normality test result.</p>
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40 pages, 4859 KiB  
Systematic Review
A Systematic Review on the Risk of Overheating in Passive Houses
by Ensiyeh Farrokhirad, Yun Gao, Adrian Pitts and Guo Chen
Buildings 2024, 14(8), 2501; https://doi.org/10.3390/buildings14082501 - 13 Aug 2024
Abstract
The rise in energy-efficient building strategies, driven by the intensifying energy crisis, has encouraged the development of the passive house (PH) approach. However, existing research highlights a potential downside, the perception of the overheating risk in hot periods, particularly when design and construction [...] Read more.
The rise in energy-efficient building strategies, driven by the intensifying energy crisis, has encouraged the development of the passive house (PH) approach. However, existing research highlights a potential downside, the perception of the overheating risk in hot periods, particularly when design and construction methods fail to incorporate adequate mitigation strategies. This study examines the pressing necessity of addressing overheating risks in PHs through a systematic review. The aim is to identify key factors reported as contributing to overheating, to evaluate recommended solutions across diverse global regions, and to identify methods to reduce the risk. This review indicates that PHs are considered at risk of overheating in the hot periods of the year across many climatic regions, exacerbated by the impacts of climate change. Architectural features, climate conditions, inhabitants’ behaviors, and perceptions of the quality of indoor spaces are important factors affecting PH overheating and should be considered at the design stage. It is concluded that the urban context, building envelope characteristics, and their impacts require greater attention. Based on the knowledge gaps identified, green walls are proposed as a nature-based solution with good potential for mitigating overheating in PHs. More integrated consideration of all factors and solutions can minimize current and future risks. Full article
(This article belongs to the Section Building Energy, Physics, Environment, and Systems)
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<p>Conceptual framework of study.</p>
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<p>Database diagram constructed according to PRISMA approach (used under terms of CC BY 4.0 License) [<a href="#B13-buildings-14-02501" class="html-bibr">13</a>].</p>
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<p>The climatic spread and frequency of overheated PH cases, according to studies.</p>
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<p>Mapping the geographical spread of overheated PH examples.</p>
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<p>Co-occurrence network of keywords.</p>
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<p>The rise in studies on the overheating risk of passive houses between 2001 and 2024.</p>
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<p>Distribution of methodologies used in studies post-2011.</p>
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<p>Location-based number of overheated cases based on studies.</p>
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<p>The frequency of overheated spaces in PH buildings according to the reviewed studies.</p>
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<p>The frequency of various architectural solutions to minimize the overheating risk in PHs recommended in the reviewed studies.</p>
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<p>An example of a PH plant-covered façade proposed by the authors.</p>
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14 pages, 3916 KiB  
Article
Estimation of Particulate Matter Levels in City Center Pedestrian Routes with the Aid of Low-Cost Sensors
by Dimos Dimitrios Plakotaris, Theodosios Kassandros, Evangelos Bagkis and Kostas Karatzas
Atmosphere 2024, 15(8), 965; https://doi.org/10.3390/atmos15080965 (registering DOI) - 13 Aug 2024
Abstract
Particulate matter is one of the most dangerous air pollutants, especially in urban areas, due to its significant adverse health effects. Traditionally, air quality monitoring relies on fixed reference stations, which often have a low temporal and spatial resolution. To address this limitation, [...] Read more.
Particulate matter is one of the most dangerous air pollutants, especially in urban areas, due to its significant adverse health effects. Traditionally, air quality monitoring relies on fixed reference stations, which often have a low temporal and spatial resolution. To address this limitation, a low-cost, portable air quality monitoring device with a rapid measurement response was used to assess particulate matter concentration levels in the afternoon hours in central Thessaloniki, Greece. This approach enabled the identification of local hotspots directly related to human activities. Statistical analysis and spatial mapping were employed, and data collected were categorized using k-means clustering. The findings of the study suggest that data acquired via portable low-cost sensors can describe the local variability of PM2.5 concentrations. The results indicate that local activities, such as increased human accumulation, traffic congestion at traffic lights, market working hours, together with meteorological parameters, can significantly impact air quality in specific urban locations. They also highlight the differences between data recorded in colder and warmer periods, with the concentrations of PM2.5 in the first period being 3.7 μg/m3 greater on average than in the second. These differences are also identified via the k-means clustering method, which suggest that higher concentrations appear mostly during the colder period of the study. Full article
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<p>Configuration of the overall AQ sensor system.</p>
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<p>Routes carried out: (a) Western Section of the Center—Mitropoleos Front; (b) Western Section of the Center—Tsimiski Front; (c) Western Part of the Center—Coastal front; (d) Eastern Section of the Center—Tsimiski Front; (e) Eastern Section of the Center—Mitropoleos Front; (f) Eastern section of the Center—Coastal front. The thick dashed line indicates the Agias Sofias street axis, separating the western from the eastern section of the city center.</p>
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<p>Comparison of recorded PM<sub>2.5</sub> and PM<sub>10</sub> concentrations (in μg/m<sup>3</sup>) from the low-cost portable AQ sensor and from the KASTOM nodes at: (<b>a</b>) the experimental school; (<b>b</b>) Agia Sofia (close to Tsimiski street); (<b>c</b>) Kapani market. Date is indicated in numerical format as year-month-day.</p>
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<p>Map of the (<b>a</b>) mean values and (<b>b</b>) standard deviations (over the measurement period) of PM<sub>2.5</sub> concentrations within the monitored area (in μg/m<sup>3</sup>).</p>
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<p>Map of the five highest concentrations of PM<sub>2.5</sub> for each day of measurements. (1) Egnatia and Agias Sofia street intersection; (2) Egnatia and Aristotle Road intersection; (3) Dimitriou Gounari street; (4) Tsimiski and Agias Sofia street intersection; (5) Navarinou Square; (6) Nikis Avenue; (7) Eleftheriou Venizelou street; (8) Ermou street; (9) Pavlou Mela street; (10) Agiou Dimitriou and Agias Sofias street intersection; (11) Agias Sofias and Filippou street intersection; (12) Iasonidou street; (13) Al. Svolou street; (14) Gr. Palama and Pavlou Mela streets intersection. (Map data copyrighted OpenStreetMap contributors and available from <a href="https://www.openstreetmap.org" target="_blank">https://www.openstreetmap.org</a>, assessed on 2 July 2024).</p>
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<p>Box plot of clusters and the PM<sub>2.5</sub> concentration values they contain (in μg/m<sup>3</sup>). The horizontal line in the box area corresponds to the median value, while the box height corresponds to the 50% concentration value range (25% up to 75%).</p>
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<p>Visualization of the measurement locations belonging to each cluster. (a): data collected during the warmer period; (b) data collected during the colder period.</p>
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<p>A picture of the portable low-cost air quality sensor system used in the study.</p>
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21 pages, 1255 KiB  
Article
Can Smart City Construction Promote Urban Green and High-Quality Development?—Validation Analysis from 156 Cities in China
by Shilong Li and Rui Wang
Buildings 2024, 14(8), 2500; https://doi.org/10.3390/buildings14082500 - 13 Aug 2024
Abstract
The in-depth participation and application of new-generation information and communication technologies, such as big data, Internet of Things, artificial intelligence, etc., in the field of smart cities have promoted their abilities in urban fine governance, public services, ecological livability, scientific and technological innovation, [...] Read more.
The in-depth participation and application of new-generation information and communication technologies, such as big data, Internet of Things, artificial intelligence, etc., in the field of smart cities have promoted their abilities in urban fine governance, public services, ecological livability, scientific and technological innovation, etc. Smart cities are gradually becoming recognized as the best solution to “urban problems”. Smart city construction drives urban innovative development, accumulates kinetic energy for economic growth, strengthens social support functions, enhances the effectiveness of the ecological environment, and promotes the convergence and integration of urban green development and high-quality development. This paper constructs a difference-in-differences model based on propensity score matching. Additionally, fiscal science and technology investment is introduced as mediating variables to further explain the mechanism through which smart city pilot policy impacts urban green and high-quality development. This research uses panel data from 156 prefecture-level cities in China from 2006 to 2019 to empirically test that the construction of smart cities has a significant positive effect on urban green and high-quality development. The mediation effect model shows that an increase in the level of local government’s fiscal science and technology investment enhances the positive effect of smart city construction on urban green and high-quality development. This research concludes with policy recommendations: the government should seize the development opportunity presented by smart city pilot policy, providing necessary policy support and financial incentive for the construction of smart cities. This will optimize the local economic structure, transform the driving forces of urban development, and assist cities in achieving green and high-quality development. Full article
(This article belongs to the Special Issue Research on Smart Healthy Cities and Real Estate)
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<p>The mechanism of smart city construction affecting green high-quality development.</p>
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<p>The moderating effect of financial investment of science and technology.</p>
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<p>Time–trend graph.</p>
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<p>Dynamic effect graph.</p>
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25 pages, 6997 KiB  
Article
Validation of Multi-Temporal Land-Cover Products Considering Classification Error Propagation
by Shicheng Liao, Huan Xie, Yali Gong, Yanmin Jin, Xiong Xu, Peng Chen and Xiaohua Tong
Remote Sens. 2024, 16(16), 2968; https://doi.org/10.3390/rs16162968 - 13 Aug 2024
Abstract
Reducing the lag in the accuracy assessment of multi-temporal land-cover products has been a hot research topic. By identifying the changed strata, the annual accuracy in multi-temporal products can be quickly evaluated. However, there are still two limitations in the accuracy assessment of [...] Read more.
Reducing the lag in the accuracy assessment of multi-temporal land-cover products has been a hot research topic. By identifying the changed strata, the annual accuracy in multi-temporal products can be quickly evaluated. However, there are still two limitations in the accuracy assessment of multi-temporal products. Firstly, the setting of the parameters (e.g., the total sample size, allocation of samples in the changed strata, etc.) in the fundamental sampling design is not based on specific setting criteria. Therefore, this evaluation method is not always applicable when the product or research area changes. Secondly, the accuracy evaluation of multi-temporal products does not consider the influence of misclassification. This can lead to an overestimation of the accuracy of changed strata in single-year evaluations. In this paper, we describe how the total sample and the assignment of samples in every stratum can be adjusted according to the characteristics of the land-cover product, which improves the applicability of the evaluation. The samples in the changed strata that propagate misclassification are essentially pixels that have not undergone any land-cover change. Therefore, in order to eliminate the propagation of this inter-annual classification error, the misclassified samples are reclassified as unchanged strata. This method was used in the multi-temporal ESA CCI land-cover product. The experimental results indicate that the single-year accuracy, considering classification error, is closer to the traditional evaluation accuracy of single-temporal data. For the categories with a small ratio of unchanged strata samples to changed strata samples, the accuracy improvement, after eliminating the classification errors, is more obvious. For the urban class, in particular, the misclassification affects its estimated accuracy by 9.72%. Full article
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<p>Flowchart of time-series sampling.</p>
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<p>Minimum sample size calculated by combining the predicted user precision error rate and significance level.</p>
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<p>Relationship between strata and map classes.</p>
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<p>Misclassification propagation of pixels in the changed strata. The unchanged strata include pixels 1 to 6. The changed strata include pixels 7 to 9. ① indicates that the map and reference data in the changed strata are consistent in the two years; ② is the inconsistency between the map class and the reference in the year (T + 1); Light green means grass; Dark green means forest.</p>
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<p>Interpretation results for the ESA CCI LC data in Google Earth. The red frame refers to the area range of pixel.</p>
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<p>Spatial layout of samples in the base year.</p>
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<p>Proportion of feature categories between the randomly revisited samples and total samples.</p>
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<p>Spatial distribution of the samples. (<b>a</b>) Samples in 2010. (<b>b</b>–<b>f</b>) Samples randomly revisited in the years from 2011 to 2015.</p>
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<p>Spatial distribution of the samples. (<b>a</b>) Samples in 2010. (<b>b</b>–<b>f</b>) Samples randomly revisited in the years from 2011 to 2015.</p>
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<p>Single-year precision results for the average of 10 times extracted from the single-temporal samples in 2015. (<b>a</b>) Difference between the accuracy when eliminating the misclassification and including the misclassification. (<b>b</b>) Difference between the single-year accuracy and single-temporal accuracy. WMC represents the difference between the accuracy when eliminating misclassification and the single-temporal accuracy (reference value). IMC represents the difference between the accuracy when including the misclassification and the single-temporal accuracy.</p>
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<p>Single-year precision results of the average of ten times extracted from single-temporal samples in 2010. (<b>a</b>) Difference between the accuracy of eliminating the misclassification and including the misclassification. (<b>b</b>) Difference between the single-year accuracy and single-temporal accuracy.</p>
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<p>Single-year precision results of the average of ten times extracted from single-temporal samples in 2010.</p>
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<p>The accuracy of the <b>ESA CCI LC</b> for 2010–2015.</p>
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<p>User’s accuracy and producer’s accuracy of each class. (<b>a</b>) refers to Crop; (<b>b</b>) refers to Forest; (<b>c</b>) refers to Grass; (<b>d</b>) refers to Shrub; (<b>e</b>) refers to Water; (<b>f</b>) refers to Bareland; (<b>g</b>) refers to Urban; (<b>h</b>) refers to Snow; (<b>i</b>) refers to Sparse Veg.</p>
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<p>User’s accuracy and producer’s accuracy of each class. (<b>a</b>) refers to Crop; (<b>b</b>) refers to Forest; (<b>c</b>) refers to Grass; (<b>d</b>) refers to Shrub; (<b>e</b>) refers to Water; (<b>f</b>) refers to Bareland; (<b>g</b>) refers to Urban; (<b>h</b>) refers to Snow; (<b>i</b>) refers to Sparse Veg.</p>
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<p>Stability of the producer’s accuracy for the ESA CCI LC product.</p>
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<p>Stability of the user’s accuracy for the ESA CCI LC product.</p>
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20 pages, 10291 KiB  
Article
Summer Discrepancies between 2 m Air Temperature and Landsat LST in Suceava City, Northeastern Romania
by Dumitru Mihăilă, Petruț-Ionel Bistricean, Lucian Sfîcă, Vasilică-Dănuț Horodnic, Alin Prisăcariu and Vlad-Alexandru Amihăesei
Remote Sens. 2024, 16(16), 2967; https://doi.org/10.3390/rs16162967 - 13 Aug 2024
Abstract
The widespread availability of Land Surface Temperature (LST) data from various sources presents a contemporary challenge for urban climate studies: how to efficiently compare these data with the results of traditional methods of temperature monitoring, which typically assume measurements at 2 m under [...] Read more.
The widespread availability of Land Surface Temperature (LST) data from various sources presents a contemporary challenge for urban climate studies: how to efficiently compare these data with the results of traditional methods of temperature monitoring, which typically assume measurements at 2 m under sheltered conditions. In this line, the current study is based primarily on data extracted from a network of 31 points of hourly temperature monitoring at the 2 m level (Tair2m), in use between 2019 and 2021, in the city of Suceava in north-eastern Romania. These data allowed a detailed mapping for each hourly time step through multiple regression, adjusted by IDW, which was identified as the best interpolation method of Tair2m. These data were analyzed in parallel with LST data derived from Landsat imagery available in the analyzed period for 35 summer days with no or low cloud cover. The mapping results of both the Tair2m and LST data describe the main characteristics of the Suceava urban agglomeration (SvMA) heat island, which presents polynuclear features with intensities—as expressed by the temperature difference between the cores of the heat island and the surrounding rural areas—spanning during the summer noontime between 3.0 °C based on Tair2m and 7.1 °C on LST, respectively. The values of the Tair2m–LST differences were 0.68 °C on average, ranging from 5.33 to −19.17 °C, directly proportional to the imperviousness ratio (IMD) values, reaching the highest values in the local climate zones (LCZs) with a high built-up ratio (up to −19.17 °C) and the lowest (0.5 ÷ −0.5 °C) for those with bare soils, with isolated bushes and trees, with few or no buildings. The study results could serve as a tool to downscale the LST data to the level of Tair2m, which is useful for interpretation of the data derived from these commonly used tools in urban climate monitoring. Full article
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<p>The location of SvMA in Europe (<b>a</b>), in the north-east of Romania (<b>b</b>), and the detailed physico-geographical conditions within the administrative boundaries [<a href="#B43-remotesensing-16-02967" class="html-bibr">43</a>], as well as the position of the meteorological posts and stations where the Tair2m observations were carried out during the 2019–2021 interval (<b>c</b>).</p>
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<p>The regression lines and equations for the measured and estimated values at the 31 observation points resulting from data interpolation through the method of multiple regression with IDW.</p>
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<p>The LCZs map of the Suceava metropolitan area (<b>a</b>). The share of different areas of the LCZs from SvMA surface (2023). (<b>b</b>) Designation of LCZ types in the metropolitan area of Suceava (<b>c</b>).</p>
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<p>Spatial distribution of the mean thermal values in SvMA in the interval 2019–2021 from in situ measurements at Tair2m (<b>a</b>) and Landsat LST (<b>b</b>) for the 35 analyzed time steps.</p>
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<p>Thermal profiles of Tair2m and LST on the NE–SW (<b>a</b>) and NW–SE (<b>b</b>) directions over SvMA during sunny summer days (2019–2021).</p>
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<p>Spatial distribution of the mean thermal values in the municipality of Suceava in the interval 2019–2021 for summer sunny days from Tair2m measurements (<b>a</b>) and LST satellite imagery (<b>b</b>) for the 35 analyzed time steps.</p>
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<p>Spatial distribution of the differences between the numerical models of Tair2m and LST (Tair2m—LST) for the 35 analyzed time steps of summer sunny days over SvMA in the interval 2019–2021.</p>
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<p>Histograms showing the Tair2m and LST baseline thermal parameters for SvMA and their differences for the 35 hourly sequences of in situ determinations synchronous to the 35 Landsat satellite scenes used in the thermal modeling for the summer days in the interval 2019–2021.</p>
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<p>IMD ratio regionalized by the kernel density estimation method for urban agglomerations (<b>a</b>) and city areas (<b>b</b>).</p>
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<p>NW–SE (<b>a</b>) and NE–SW (<b>b</b>) profile IMD ratio, over SvMA.</p>
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<p>The average values of Tair2m and LST on IMD thresholds obtained from gridded points at 500 m grids (1626 values) for SvMA (2019–2021).</p>
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21 pages, 4752 KiB  
Article
The Spatial Pattern Evolution of Urban Innovation Actors and the Planning Response to Path Dependency: A Case Study of Guangzhou City, China
by Luhui Qi, Yuan Zhang, Yuanyi Chen, Lu Chen, Shuli Zhou and Xiaoli Wei
Urban Sci. 2024, 8(3), 111; https://doi.org/10.3390/urbansci8030111 - 13 Aug 2024
Abstract
The capacity for urban innovation is a significant symbol of contemporary urban development. In order to promote sustainable urban innovation, it is crucial to match and optimize innovation spaces, actors, and their behavioral needs. Based on the data from patent inventions, which are [...] Read more.
The capacity for urban innovation is a significant symbol of contemporary urban development. In order to promote sustainable urban innovation, it is crucial to match and optimize innovation spaces, actors, and their behavioral needs. Based on the data from patent inventions, which are commonly used to represent urban innovation, in this study, we investigated the formation mechanism of Guangzhou’s innovation pattern and its characteristics from 1990 to 2020 using Geographic Information System (GIS) technology. The results indicated that Guangzhou’s innovation spaces developed a center-radiation structure of “two districts and seven cores”. We investigated the path dependence of spaces, actors, and behavioral needs by examining the interaction between the innovation space layout and behavioral needs. The findings provide theoretical support for the city’s sustainable development in terms of innovation in the future. Full article
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<p>(<b>a</b>) Location of Guangzhou in China; (<b>b</b>) administrative divisions of Guangzhou.</p>
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<p>Schematic diagrams of the evolution of the hot and cold zones of the overall innovation spaces in Guangzhou, 1990–2020.</p>
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<p>A schematic diagram of the spatial distribution intensity of the overall innovation activities in Guangzhou, 1990–2020.</p>
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<p>A schematic diagram of changes in the direction of the distribution of innovation spaces in Guangzhou over the years of 1990–2020.</p>
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<p>Diagram of changes in direction of distribution of spaces of institutions and research units (<b>a</b>), individuals (<b>b</b>), and enterprises (<b>c</b>) in Guangzhou, 1990–2020.</p>
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<p>Schematic representation of spatial distribution of probe factor categorization.</p>
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<p>Influence elements and path dependence of urban innovation spaces.</p>
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21 pages, 6293 KiB  
Study Protocol
Flocculants for the High-Concentration Activated Sludge Method and the Effectiveness of Urban Wastewater Treatment
by Benfu Luo, Haixin He, Yujing Yan, Yin Wang, Xi Yang, Yuhang Liu, Jiaran Xu and Weiheng Huang
Water 2024, 16(16), 2281; https://doi.org/10.3390/w16162281 - 13 Aug 2024
Abstract
In this paper, the three inorganic flocculants polymeric chloride PAC, FeCl3, and Al2(SO4)3 and two organic flocculants anionic polyacrylamide APAM and cationic polyacrylamide CPAM were screened to determine the most efficient flocculants and the optimal dosage, [...] Read more.
In this paper, the three inorganic flocculants polymeric chloride PAC, FeCl3, and Al2(SO4)3 and two organic flocculants anionic polyacrylamide APAM and cationic polyacrylamide CPAM were screened to determine the most efficient flocculants and the optimal dosage, optimizing the flocculation operating conditions through the orthogonal test and then proving the experimental effect according to a comparison study of the high-concentration method and the traditional activated sludge method. The results show that the addition of CPAM achieves the best flocculation for high-concentration activated sludge suspension, and that the sludge interface descent rate, sludge volume index, and sludge settling ratio are better than those of other flocculants. The orthogonal test was used on the sludge volume index to perform evaluations and analyses: mixing section mixing intensity > Flocculation Stage 1 section mixing intensity > Flocculation Stage 2 section mixing intensity > mixing section residence time > flocculation section hydraulic residence time. In the comparison test, the settling performance of the high-concentration method was higher than that of the traditional activated sludge method. In terms of pollutant removal, the removal rates of COD, ammonia nitrogen, and total nitrogen of the traditional activated sludge method were 90.85%, 95.74%, and 71.6%, respectively. The average removal rates of COD, ammonia nitrogen, and total nitrogen of high-concentration activated sludge method were 92.24%, 97.28%, and 80.97%—higher than that of the traditional activated sludge method. Full article
(This article belongs to the Special Issue Advanced Technologies in Water Treatment)
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<p>(<b>a</b>) is the molecular structure of CPAM and (<b>b</b>) is the molecular structure of APAM.</p>
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<p>Pictures (<b>a</b>–<b>d</b>) all show the site of the beaker experiment.</p>
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<p>Pictures (<b>a</b>–<b>d</b>) all show the site of the beaker experiment.</p>
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<p>Flowchart of the medium-sized test.</p>
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<p>(<b>a</b>–<b>d</b>) show all the medium-sized test sites.</p>
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<p>Changes in sludge volume of mixtures with different dosages of PAC.</p>
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<p>Changes in sludge volume of mixed liquor with different dosages of FeCl<sub>3</sub>.</p>
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<p>Variation in sludge volume of mixed liquor with different dosages of Al<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>.</p>
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<p>Changes in sludge volume of mixed liquor with different dosages of APAM.</p>
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<p>Variation in sludge volume of mixtures with different dosages of CPAM.</p>
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<p>Comparison of sludge concentration between System I and System II.</p>
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<p>Comparison of System I and System II sludge SV and SVI.</p>
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<p>Comparison of sludge COD removal effect between System I and System II.</p>
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<p>Comparison of ammonia nitrogen removal effect between System I and System II.</p>
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<p>Comparison of total nitrogen removal effect between System I and System II.</p>
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<p>Morphology of activated sludge micelles in two systems.</p>
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<p>Microscopic examination of aerobic granular sludge.</p>
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<p>(<b>a</b>) is a bellworm, (<b>b</b>) is a ladybird beetle, (<b>c</b>) is a skunk bug, (<b>d</b>) is a saddle beetle rotifer, (<b>e</b>) is a nematode, and (<b>f</b>) is a bellworm.</p>
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<p>(<b>a</b>) is a bellworm, (<b>b</b>) is a ladybird beetle, (<b>c</b>) is a skunk bug, (<b>d</b>) is a saddle beetle rotifer, (<b>e</b>) is a nematode, and (<b>f</b>) is a bellworm.</p>
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1 pages, 255 KiB  
Correction
Correction: Martel-Rodríguez et al. Long-Term Performance of a Hybrid-Flow Constructed Wetlands System for Urban Wastewater Treatment in Caldera de Tirajana (Santa Lucía, Gran Canaria, Spain). Int. J. Environ. Res. Public Health 2022, 19, 14871
by Gilberto M. Martel-Rodríguez, Vanessa Millán-Gabet, Carlos A. Mendieta-Pino, Eva García-Romero and José R. Sánchez-Ramírez
Int. J. Environ. Res. Public Health 2024, 21(8), 1058; https://doi.org/10.3390/ijerph21081058 - 13 Aug 2024
Abstract
There was an error in the original publication [...] Full article
(This article belongs to the Section Environmental Science and Engineering)
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