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Search Results (1,108)

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Keywords = resource substitutability

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20 pages, 642 KiB  
Article
A Quantitative Study on the Interactive Changes Between China’s Final Demand Structure and Forestry Industry Production Structure
by Wenting Jia, Fuliang Cao and Xiaofeng Jia
Forests 2025, 16(8), 1212; https://doi.org/10.3390/f16081212 - 23 Jul 2025
Abstract
The effects of changes in China’s final demand structure on its forestry sector and associated supply chains have not been thoroughly examined. This study aims to provide a detailed analysis of the quantitative relationships and underlying mechanisms between these interactive changes. Using China’s [...] Read more.
The effects of changes in China’s final demand structure on its forestry sector and associated supply chains have not been thoroughly examined. This study aims to provide a detailed analysis of the quantitative relationships and underlying mechanisms between these interactive changes. Using China’s 153-sector input–output tables from the National Bureau of Statistics and applying a Leontief-based input–output model, we conducted scenario simulations through three distinct schemes, generating both quantitative and qualitative results. Our findings indicate that (1) For China’s forestry sector and its entire value chain to thrive, policymakers should boost consumer demand. This can better stimulate the development of forestry and the “agriculture-forestry-animal husbandry-fishery services” sector and related service industries; (2) Increased investment demand effectively stimulates the development of tertiary industries and secondary industries within the forestry supply chain and boosts the demand and production of intermediate products; (3) Changes in net exports have a significant impact on forestry and the forestry industry chain. To reduce dependence on foreign timber resources, China should strategically expand commercial plantation development; (4) Regarding intermediate product production, investment has a more pronounced effect on increasing total volume compared to consumption. Additionally, the Sino–US tariff disputes negatively impact the forestry industries of both countries. China needs to accelerate import substitution strategies for timber products, adjust international trade markets, and expand domestic consumption and investment to ensure the healthy and stable development of its forestry sector. Full article
(This article belongs to the Section Forest Economics, Policy, and Social Science)
26 pages, 3891 KiB  
Article
Investigation of Hollow Block Production by Substituting Chicken Feather, Cotton and Rock Wool Waste Fibers for Pumice Aggregate
by Ela Bahsude Gorur Avsaroglu
Buildings 2025, 15(15), 2587; https://doi.org/10.3390/buildings15152587 - 22 Jul 2025
Viewed by 93
Abstract
Currently, natural resources are rapidly depleting as a result of increasing construction facilities. Increasing energy consumption with increasing construction is another serious issue. In addition, many problems that threaten the environment and human health arise during the disposal and storage of waste materials [...] Read more.
Currently, natural resources are rapidly depleting as a result of increasing construction facilities. Increasing energy consumption with increasing construction is another serious issue. In addition, many problems that threaten the environment and human health arise during the disposal and storage of waste materials obtained in different sectors. The main objective of this study is to investigate the substitution of cotton (CW), chicken feather (CFF) and stone wool waste (SWW) from pumice aggregate in the production of environmentally friendly hollow blocks. To achieve this, CW, CFF and SWW were substituted for pumice at ratios of 2.5–5–7.5–10% in mass, and hollow blocks were produced with this mixture under low pressure and vibrations in a production factory. Various characterization methods, including a size and tolerance analysis, unit volume weight test, thermal conductivity test, durability test, water absorption test and strength tests, were carried out on the samples produced. This study showed that waste fibers of chicken feather and stone wool are suitable for the production of sustainable and environmentally friendly hollow blocks that can reduce the dead load of the building, have sufficient strength, provide energy efficiency due to low thermal conductivity and have a high durability due to a low water absorption value. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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15 pages, 1273 KiB  
Article
Screening of Substrates and Optimization of Formulations for Exogenous Nutrient Bags of Morchella sextelata (Black Morel)
by Qi Yan, Weidong Zhang, Qi Wang, Tonghui Yang, Peng Wang, Ya Yu, Xiao Tan, Xueping Kang and Jiawei Wen
Horticulturae 2025, 11(7), 863; https://doi.org/10.3390/horticulturae11070863 - 21 Jul 2025
Viewed by 78
Abstract
In the artificial cultivation of Morchella sextelata (Black Morel), exogenous nutrient bags (ENBs) commonly employ wheat grains as the primary substrate raw material. However, this approach is costly and runs counter to the “non-grain” development direction advocated by the edible mushroom industry. Under [...] Read more.
In the artificial cultivation of Morchella sextelata (Black Morel), exogenous nutrient bags (ENBs) commonly employ wheat grains as the primary substrate raw material. However, this approach is costly and runs counter to the “non-grain” development direction advocated by the edible mushroom industry. Under controlled field conditions, twelve self-made formulations were set up and compared with a conventional market formulation to comprehensively analyze their impacts on the agronomic traits, yield, soil physicochemical properties, and economic benefits of M. sextelata fruiting bodies. The research findings indicate that the nutrient bag formulations have a significant effect on soil available nutrients. Specifically, the contents of alkali-hydrolysable nitrogen (AN) and available potassium (AK) exhibit a significantly negative correlation with M. sextelata yield (r = −0.60, p < 0.05; r = −0.72, p < 0.01, respectively). Among all the treatment groups, the KY1 formulation (comprising 30% wheat grains, 5% rice bran, 60% corncobs, 2% rice husks, 1% lime, and 1% gypsum) achieved the highest yield of 915.13 kg per 667 m2, which was 16.1% higher than that of the control group. The net economic benefit per unit area (667 m2) reached CNY 75,282.15, representing a 20.7% increase compared to the traditional wheat grains-based formulation. In conclusion, partially substituting wheat grains with rice bran in ENBs can not only reduce reliance on staple food resources but also enhance yield and economic efficiency. Due to the differences in cultivated strains and environmental conditions, the impact on morel yield is substantial; therefore, the results of this study need further validation through pilot trials. Full article
(This article belongs to the Section Medicinals, Herbs, and Specialty Crops)
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20 pages, 2239 KiB  
Article
Synthesis of Biomass Polycarboxylate Superplasticizer and Its Performance on Cement-Based Materials
by Zefeng Kou, Kaijian Huang, Muhua Chen, Hongyan Chu, Linye Zhou and Tianqi Yin
Materials 2025, 18(14), 3416; https://doi.org/10.3390/ma18143416 - 21 Jul 2025
Viewed by 207
Abstract
Polycarboxylate superplasticizer (PCE) is an important part of improving the overall performance of concrete. However, its synthetic raw materials are overly dependent on petrochemical products, and it also causes problems such as environmental pollution. With the development of the building material industry, the [...] Read more.
Polycarboxylate superplasticizer (PCE) is an important part of improving the overall performance of concrete. However, its synthetic raw materials are overly dependent on petrochemical products, and it also causes problems such as environmental pollution. With the development of the building material industry, the demand for petrochemical resources required for synthetic water-reducing agents will increase rapidly. Therefore, there is an urgent need to transition the synthetic raw materials of PCE from petrochemicals to biomass materials to reduce the consumption of nonrenewable resources as well as the burden on the environment. Biomass materials are inexpensive, readily available and renewable. Utilizing biomass resources to develop good-performing water-reducing agents can reduce the consumption of fossil resources. This is conducive to carbon emission reduction in the concrete material industry. In addition, it promotes the high-value utilization of biomass resources. Therefore, in this study, a biomass polyether monomer, acryloyl hydroxyethyl cellulose (AHEC), was synthesized from cellulose via the reaction route of ethylene oxide (EO) etherification and acrylic acid (AA) esterification. Biomass polycarboxylate superplasticizers (PCE-Cs) were synthesized through free radical polymerization by substituting AHEC for a portion of the frequently utilized polyether monomer isopentenyl polyoxyethylene ether (TPEG). This study primarily focused on the properties of PCE-Cs in relation to cement. The findings of this study indicated that the synthesized PCE-C5 at a dosing of 0.4% (expressed as mass fraction of cement) when the AHEC substitution ratio was 5% achieved good water reduction properties and significant delays. With the same fluidity, PCE-C5 could enhance the mechanical strength of cement mortar by 30% to 40%. This study utilized green and low-carbon biomass resources to develop synthetic raw materials for water-reducing agents, which exhibited effective water-reducing performance and enhanced the utilization rate of biomass resources, demonstrating significant application value. Full article
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13 pages, 2340 KiB  
Article
The Microscopic Mechanism of High Temperature Resistant Core-Shell Nano-Blocking Agent: Molecular Dynamics Simulations
by Zhenghong Du, Jiaqi Xv, Jintang Wang, Juyuan Zhang, Ke Zhao, Qi Wang, Qian Zheng, Jianlong Wang, Jian Li and Bo Liao
Polymers 2025, 17(14), 1969; https://doi.org/10.3390/polym17141969 - 17 Jul 2025
Viewed by 233
Abstract
China has abundant shale oil and gas resources, which have become a critical pillar for future energy substitution. However, due to the highly heterogeneous nature and complex pore structures of shale reservoirs, traditional plugging agents face significant limitations in enhancing plugging efficiency and [...] Read more.
China has abundant shale oil and gas resources, which have become a critical pillar for future energy substitution. However, due to the highly heterogeneous nature and complex pore structures of shale reservoirs, traditional plugging agents face significant limitations in enhancing plugging efficiency and adapting to extreme wellbore environments. In response to the technical demands of nanoparticle-based plugging in shale reservoirs, this study systematically investigated the microscopic interaction mechanisms of nano-plugging agent shell polymers (Ployk) with various reservoir minerals under different temperature and salinity conditions using molecular simulation methods. Key parameters, including interfacial interaction energy, mean square displacement, and system density distribution, were calculated to thoroughly analyze the effects of temperature and salinity variations on adsorption stability and structural evolution. The results indicate that nano-plugging agent shell polymers exhibit pronounced mineral selectivity in their adsorption behavior, with particularly strong adsorption performance on SiO2 surfaces. Both elevated temperature and increased salinity were found to reduce the interaction strength between the shell polymers and mineral surfaces and significantly alter the spatial distribution and structural ordering of water molecules near the interface. These findings not only elucidate the fundamental interfacial mechanisms of nano-plugging agents in shale reservoirs but also provide theoretical guidance for the precise design of advanced nano-plugging agent materials, laying a scientific foundation for improving the engineering application performance of shale oil and gas wellbore-plugging technologies. Full article
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26 pages, 2472 KiB  
Article
Incorporating Recyclates Derived from Household Waste into Flexible Food Packaging Applications: An Environmental Sustainability Assessment
by Trang T. Nhu, Anna-Sophie Haslinger, Sophie Huysveld and Jo Dewulf
Recycling 2025, 10(4), 142; https://doi.org/10.3390/recycling10040142 - 17 Jul 2025
Viewed by 205
Abstract
Integrating recyclates into food packaging is key towards circularity while meeting functionality and safety requirements; however, associated environmental impacts remain underexplored. This gap was addressed through a cradle-to-gate life cycle assessment, using the Environmental Footprint method, along with substitution and cut-off approaches for [...] Read more.
Integrating recyclates into food packaging is key towards circularity while meeting functionality and safety requirements; however, associated environmental impacts remain underexplored. This gap was addressed through a cradle-to-gate life cycle assessment, using the Environmental Footprint method, along with substitution and cut-off approaches for handling the multifunctionality of recycling. Recyclates were derived from polyethylene (PE)-rich household food packaging waste, purified via delamination-deinking. Firstly, results show that shifting from virgin multi-material to mono-material multilayer structures with or without recyclates, while maintaining functionality, offers environmental benefits. Secondly, recyclates should sufficiently substitute virgin materials in quantity and quality, decreasing the need for primary plastics and avoiding recyclate incorporation without functionality. Otherwise, thicker laminates are obtained, increasing processability challenges and environmental impacts, e.g., 12% for particulate matter, and 14% for mineral-metal resource use when the recycle content rises from 34 to 50%. Thirdly, a fully closed loop for flexible food packaging is not yet feasible. Key improvements lie in reducing residues generated during recycling, especially in delamination-deinking, lowering energy use in recompounding, and using more efficient transport modes for waste collection. Further research is essential to optimise the innovative technologies studied for flexible food packaging and refine them for broader applications. Full article
(This article belongs to the Special Issue Challenges and Opportunities in Plastic Waste Management)
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28 pages, 9297 KiB  
Article
Sustainable Lightweight Aggregates from Diatomite Residue
by Maelson Mendonça de Souza, Normando Perazzo Barbosa, Marcos Alyssandro Soares dos Anjos, Evilane Cássia de Farias, João Gabriel Cruz Aguiar, José Anselmo da Silva Neto and Cinthia Maia Pederneiras
Sustainability 2025, 17(14), 6508; https://doi.org/10.3390/su17146508 - 16 Jul 2025
Viewed by 198
Abstract
This study assessed the feasibility of producing lightweight aggregates (LWAs) using diatomite waste (DW) as a clay substitute. The research aimed to reduce the consumption of natural resources and minimise the environmental impacts caused by the disorderly disposal of DW. Chemical, physical, and [...] Read more.
This study assessed the feasibility of producing lightweight aggregates (LWAs) using diatomite waste (DW) as a clay substitute. The research aimed to reduce the consumption of natural resources and minimise the environmental impacts caused by the disorderly disposal of DW. Chemical, physical, and mechanical tests were carried out on six formulations of mixtures containing 50% to 100% DW, sintered between 1100 and 1250 °C, resulting in 24 samples. The aggregates had a particle density between 1.14 and 2.13 g/cm3, a maximum bloating index of 5.7%, a crushing strength of up to 11.14 MPa, and a mass loss of up to 8.7%. Minimum porosity of 2.8 percent and water absorption of 2.0 percent were observed. Sixteen samples met the criteria required for commercial applications, demonstrating that replacing clay with DW is technically feasible. The high porosity of DW was found to influence the density of the LWAs. The findings of this study highlight the environmental sustainability of using DW as an alternative raw material, contributing to circular economy strategies in the construction sector. Full article
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22 pages, 1279 KiB  
Review
State of the Art of Biomethane Production in the Mediterranean Region
by Antonio Comparetti, Salvatore Ciulla, Carlo Greco, Francesco Santoro and Santo Orlando
Agronomy 2025, 15(7), 1702; https://doi.org/10.3390/agronomy15071702 - 15 Jul 2025
Viewed by 295
Abstract
The Mediterranean region is increasingly confronted with intersecting environmental, agricultural, and socio-economic challenges, including biowaste accumulation, soil degradation, and high dependency on imported fossil fuels. Biomethane, a renewable substitute for natural gas, offers a strategic solution that aligns with the region’s need for [...] Read more.
The Mediterranean region is increasingly confronted with intersecting environmental, agricultural, and socio-economic challenges, including biowaste accumulation, soil degradation, and high dependency on imported fossil fuels. Biomethane, a renewable substitute for natural gas, offers a strategic solution that aligns with the region’s need for sustainable energy transition and circular resource management. This review examines the current state of biomethane production in the Mediterranean area, with a focus on anaerobic digestion (AD) technologies, feedstock availability, policy drivers, and integration into the circular bioeconomy (CBE) framework. Emphasis is placed on the valorisation of regionally abundant feedstocks such as olive pomace, citrus peel, grape marc, cactus pear (Opuntia ficus-indica) residues, livestock manure, and the Organic Fraction of Municipal Solid Waste (OFMSW). The multifunctionality of AD—producing renewable energy and nutrient-rich digestate—is highlighted for its dual role in reducing greenhouse gas (GHG) emissions and restoring soil health, especially in areas threatened by desertification such as Sicily (Italy), Spain, Malta, and Greece. The review also explores emerging innovations in biogas upgrading, nutrient recovery, and digital monitoring, along with the role of Renewable Energy Directive III (RED III) and national biomethane strategies in scaling up deployment. Case studies and decentralised implementation models underscore the socio-technical feasibility of biomethane systems across rural and insular territories. Despite significant potential, barriers such as feedstock variability, infrastructural gaps, and policy fragmentation remain. The paper concludes with a roadmap for research and policy to advance biomethane as a pillar of Mediterranean climate resilience, energy autonomy and sustainable agriculture within a circular bioeconomy paradigm. Full article
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29 pages, 13314 KiB  
Article
Development of Unfired Clay Bricks with Alumina Waste from Liquid Nitrogen Production: A Sustainable Alternative for Construction Materials
by Noppadol Sangiamsak, Nopanom Kaewhanam, Meesakthana Puapitthayathorn, Seksan Numsong, Kowit Suwannahong, Sukanya Hongthong, Torpong Kreetachat, Sompop Sanongraj and Surachai Wongcharee
Sustainability 2025, 17(14), 6424; https://doi.org/10.3390/su17146424 - 14 Jul 2025
Viewed by 267
Abstract
A major breakthrough in environmentally friendly building materials is the development of sustainable unfired clay bricks including alumina waste produced during liquid nitrogen generation. Though used extensively, conventional fired clay bricks require energy-intensive manufacturing techniques that produce significant amounts of CO2 and [...] Read more.
A major breakthrough in environmentally friendly building materials is the development of sustainable unfired clay bricks including alumina waste produced during liquid nitrogen generation. Though used extensively, conventional fired clay bricks require energy-intensive manufacturing techniques that produce significant amounts of CO2 and aggravate environmental damage. By removing the need for high-temperature firing and allowing for the valorization of industrial byproducts including alumina waste and lateritic soil, unfired clay bricks offer a reasonable low-carbon alternative. High silica and alumina contents define the alumina waste, which shows pozzolanic reactivity, thus improving the physicomechanical performance of the bricks. With alumina waste substituting 0–8.57% of the cement content, seven different formulations showed improvements in compressive strength, reduced water absorption, and optimal thermal conductivity. Especially, the mechanical performance was much enhanced with alumina waste inclusion up to 30%, without sacrificing thermal insulation capacity or moisture resistance. Further supporting the environmental and financial sustainability of the suggested brick compositions is the economic viability of using industrial waste and regionally derived soils. A comparative analysis of the conventional fired bricks shows that the unfired substitutes have a much lower environmental impact and show better mechanical properties, including greater compressive strength and modulus of rupture. These results support the more general goals of circular economy systems and low-carbon urban development by highlighting the feasibility of including alumina waste and lateritic soil into sustainable building materials. Using such waste-derived inputs in building fits world initiatives to lower resource consumption, lower greenhouse gas emissions, and build strong infrastructure systems. Full article
(This article belongs to the Special Issue Solid Waste Management and Sustainable Environmental Remediation)
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16 pages, 1179 KiB  
Article
Effect and Optimal Level of Dietary Dried Watermeal (Wolffia globosa) Supplementation on the Production Performance of Two-Spotted Crickets (Gryllus bimaculatus)
by Jamlong Mitchaothai, Nils T. Grabowski, Rachakris Lertpatarakomol, Tassanee Trairatapiwan and Achara Lukkananukool
Animals 2025, 15(14), 2052; https://doi.org/10.3390/ani15142052 - 11 Jul 2025
Viewed by 198
Abstract
Watermeal (Wolffia globosa) is an emerging sustainable feed ingredient, valued for its rapid growth, high protein content, and rich nutrient profile, offering great potential to improve the efficiency and sustainability of edible cricket production systems through efficient resource use and reduced [...] Read more.
Watermeal (Wolffia globosa) is an emerging sustainable feed ingredient, valued for its rapid growth, high protein content, and rich nutrient profile, offering great potential to improve the efficiency and sustainability of edible cricket production systems through efficient resource use and reduced environmental impact. This study aimed to evaluate the effects of replacing commercial cricket feed with dried watermeal and to determine the optimal substitution level for the production performance of two-spotted crickets (Gryllus bimaculatus). Seven dietary treatments were tested, namely 0% (control; T1), 10% (T2), 25% (T3), 50% (T4), 75% (T5), 90% (T6), and 100% (T7). Crickets were reared for four weeks in an open system with 6 replicates per treatment, with each containing 120 nymphs. Body weight, feed intake, and survival rate were recorded weekly, and a production index was calculated at the end of the trial. Results showed average growth rates ranging from 7.40 to 28.20 mg/day, feed conversion ratios (FCR) between 1.03 and 1.68, survival rates of 29.28% to 69.73%, and production index values from 24.00 to 128.30. A significant decline in production efficiency (p < 0.05) was observed at substitution levels of 75% and above, with the 100% watermeal group showing the lowest production efficiency (p < 0.05), likely due to nutrient imbalances and indigestible compounds. Segmented regression analysis identified 36.7% as the optimal level of watermeal supplementation. In terms of body composition, crickets fed diets containing up to 50% watermeal (10%, 25%, and 50%) showed crude protein, crude fat, crude fiber, and ash contents comparable to those fed the commercial diet. This finding suggests that dried watermeal can replace up to 50% of the commercial cricket feed without negatively affecting growth performance, survival, or nutritional quality, with 36.7% identified as the optimal replacement level for maximizing production efficiency. Full article
(This article belongs to the Section Animal Nutrition)
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43 pages, 2590 KiB  
Article
A Study on the Impact of Industrial Robot Applications on Labor Resource Allocation
by Kexu Wu, Zhiwei Tang and Longpeng Zhang
Systems 2025, 13(7), 569; https://doi.org/10.3390/systems13070569 - 11 Jul 2025
Viewed by 318
Abstract
With the rapid advancement of artificial intelligence and smart manufacturing technologies, the penetration of industrial robots into Chinese markets has profoundly reshaped the structure of the labor market. However, existing studies have largely concentrated on the employment substitution effect and the diffusion path [...] Read more.
With the rapid advancement of artificial intelligence and smart manufacturing technologies, the penetration of industrial robots into Chinese markets has profoundly reshaped the structure of the labor market. However, existing studies have largely concentrated on the employment substitution effect and the diffusion path of these technologies, while systematic analyses of how industrial robots affect labor resource allocation efficiency across different regional and industrial contexts in China remain scarce. In particular, research on the mechanisms and heterogeneity of these effects is still underdeveloped, calling for deeper investigation into their transmission channels and policy implications. Drawing on panel data from 280 prefecture-level cities in China from 2006 to 2023, this paper employs a Bartik-style instrumental variable approach to measure the level of industrial robot penetration and constructs a two-way fixed effects model to assess its impact on urban labor misallocation. Furthermore, the analysis introduces two mediating variables, industrial upgrading and urban innovation capacity, and applies a mediation effect model combined with Bootstrap methods to empirically test the underlying transmission mechanisms. The results reveal that a higher level of industrial robot adoption is significantly associated with a lower degree of labor misallocation, indicating a notable improvement in labor resource allocation efficiency. Heterogeneity analysis shows that this effect is more pronounced in cities outside the Yangtze River Economic Belt, in those experiencing severe population aging, and in areas with a relatively weak manufacturing base. Mechanism tests further indicate that industrial robots indirectly promote labor allocation efficiency by facilitating industrial upgrades and enhancing innovation capacity. However, in the short term, improvements in innovation capacity may temporarily intensify labor mismatch due to structural frictions. Overall, industrial robots not only exert a direct positive impact on the efficiency of urban labor allocation but also indirectly contribute to resource optimization through structural transformation and innovation system development. These findings underscore the need to account for regional disparities and demographic structures when advancing intelligent manufacturing strategies. Policymakers should coordinate the development of vocational training systems and innovation ecosystems to strengthen the dynamic alignment between technological adoption and labor market restructuring, thereby fostering more inclusive and high-quality economic growth. Full article
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51 pages, 7638 KiB  
Review
Design Trends and Comparative Analysis of Lightweight Block Ciphers for IoTs
by Safia Meteb Al-Nofaie, Sanaa Sharaf and Rania Molla
Appl. Sci. 2025, 15(14), 7740; https://doi.org/10.3390/app15147740 - 10 Jul 2025
Viewed by 190
Abstract
This paper provides a comprehensive survey of 58 lightweight block ciphers (LWBCs) introduced between 2018 and 2025, designed specifically for securing resource-constrained environments such as the Internet of Things (IoTs). The ciphers are systematically categorized into five structural classes: substitution-permutation network (SPN), Feistel [...] Read more.
This paper provides a comprehensive survey of 58 lightweight block ciphers (LWBCs) introduced between 2018 and 2025, designed specifically for securing resource-constrained environments such as the Internet of Things (IoTs). The ciphers are systematically categorized into five structural classes: substitution-permutation network (SPN), Feistel network (FN), generalized Feistel network (GFN), addition-rotation-XOR (ARX), and hybrid architectures. For each cipher, key characteristics—block size, key length, structural design, number of rounds, implementation cost in gate equivalents (GEs), and known limitations—are analyzed in detail. The study offers an in-depth comparative assessment of performance, security, and implementation efficiency, providing a clear understanding of design trade-offs and cryptographic innovations. By consolidating and evaluating recent advancements in lightweight cryptography, this survey fills a crucial gap in the literature. It equips researchers, engineers, and system designers with the insights needed to make informed decisions when selecting or developing efficient cryptographic solutions tailored for modern IoTs systems. Its comprehensive scope and practical relevance make it an essential reference for advancing secure, lightweight cryptographic implementations in an increasingly connected world. Full article
(This article belongs to the Section Computing and Artificial Intelligence)
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15 pages, 1359 KiB  
Article
Phoneme-Aware Hierarchical Augmentation and Semantic-Aware SpecAugment for Low-Resource Cantonese Speech Recognition
by Lusheng Zhang, Shie Wu and Zhongxun Wang
Sensors 2025, 25(14), 4288; https://doi.org/10.3390/s25144288 - 9 Jul 2025
Viewed by 328
Abstract
Cantonese Automatic Speech Recognition (ASR) is hindered by tonal complexity, acoustic diversity, and a lack of labelled data. This study proposes a phoneme-aware hierarchical augmentation framework that enhances performance without additional annotation. A Phoneme Substitution Matrix (PSM), built from Montreal Forced Aligner alignments [...] Read more.
Cantonese Automatic Speech Recognition (ASR) is hindered by tonal complexity, acoustic diversity, and a lack of labelled data. This study proposes a phoneme-aware hierarchical augmentation framework that enhances performance without additional annotation. A Phoneme Substitution Matrix (PSM), built from Montreal Forced Aligner alignments and Tacotron-2 synthesis, injects adversarial phoneme variants into both transcripts and their aligned audio segments, enlarging pronunciation diversity. Concurrently, a semantic-aware SpecAugment scheme exploits wav2vec 2.0 attention heat maps and keyword boundaries to adaptively mask informative time–frequency regions; a reinforcement-learning controller tunes the masking schedule online, forcing the model to rely on a wider context. On the Common Voice Cantonese 50 h subset, the combined strategy reduces the character error rate (CER) from 26.17% to 16.88% with wav2vec 2.0 and from 38.83% to 23.55% with Zipformer. At 100 h, the CER further drops to 4.27% and 2.32%, yielding relative gains of 32–44%. Ablation studies confirm that phoneme-level and masking components provide complementary benefits. The framework offers a practical, model-independent path toward accurate ASR for Cantonese and other low-resource tonal languages. This paper presents an intelligent sensing-oriented modeling framework for speech signals, which is suitable for deployment on edge or embedded systems to process input from audio sensors (e.g., microphones) and shows promising potential for voice-interactive terminal applications. Full article
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23 pages, 5304 KiB  
Article
Improvement and Optimization of Underwater Image Target Detection Accuracy Based on YOLOv8
by Yisong Sun, Wei Chen, Qixin Wang, Tianzhong Fang and Xinyi Liu
Symmetry 2025, 17(7), 1102; https://doi.org/10.3390/sym17071102 - 9 Jul 2025
Viewed by 346
Abstract
The ocean encompasses the majority of the Earth’s surface and harbors substantial energy resources. Nevertheless, the intricate and asymmetrically distributed underwater environment renders existing target detection performance inadequate. This paper presents an enhanced YOLOv8s approach for underwater robot object detection to address issues [...] Read more.
The ocean encompasses the majority of the Earth’s surface and harbors substantial energy resources. Nevertheless, the intricate and asymmetrically distributed underwater environment renders existing target detection performance inadequate. This paper presents an enhanced YOLOv8s approach for underwater robot object detection to address issues of subpar image quality and low recognition accuracy. The precise measures are enumerated as follows: initially, to address the issue of model parameters, we optimized the ninth convolutional layer by substituting certain conventional convolutions with adaptive deformable convolution DCN v4. This modification aims to more effectively capture the deformation and intricate features of underwater targets, while simultaneously decreasing the parameter count and enhancing the model’s ability to manage the deformation challenges presented by underwater images. Furthermore, the Triplet Attention module is implemented to augment the model’s capacity for detecting multi-scale targets. The integration of low-level superficial features with high-level semantic features enhances the feature expression capability. The original CIoU loss function was ultimately substituted with Shape IoU, enhancing the model’s performance. In the underwater robot grasping experiment, the system shows particular robustness in handling radial symmetry in marine organisms and reflection symmetry in artificial structures. The enhanced algorithm attained a mean Average Precision (mAP) of 87.6%, surpassing the original YOLOv8s model by 3.4%, resulting in a marked enhancement of the object detection model’s performance and fulfilling the real-time detection criteria for underwater robots. Full article
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22 pages, 6546 KiB  
Article
Remote Sensing-Based Assessment of Evapotranspiration Patterns in a UNESCO World Heritage Site Under Increasing Water Competition
by Maria C. Moyano, Monica Garcia, Luis Juana, Laura Recuero, Lucia Tornos, Joshua B. Fisher, Néstor Fernández and Alicia Palacios-Orueta
Remote Sens. 2025, 17(14), 2339; https://doi.org/10.3390/rs17142339 - 8 Jul 2025
Viewed by 305
Abstract
In water-scarce regions, natural ecosystems and agriculture increasingly compete for limited water resources, intensifying stress during periods of drought. To assess these competing demands, we applied a modified PT-JPL model that incorporates the thermal inertial approach as a substitute for relative humidity ( [...] Read more.
In water-scarce regions, natural ecosystems and agriculture increasingly compete for limited water resources, intensifying stress during periods of drought. To assess these competing demands, we applied a modified PT-JPL model that incorporates the thermal inertial approach as a substitute for relative humidity (RH) in estimating soil evaporation—a method that significantly outperforms the original PT-JPL formulation in Mediterranean semi-arid irrigated areas. This remote sensing framework enabled us to quantify spatial and temporal variations in water use across both natural and agricultural systems within the UNESCO World Heritage site of Doñana. Our analysis revealed an increasing evapotranspiration (ET) trend in intensified agricultural areas and rice fields surrounding the National Park (R = 0.3), contrasted by a strong negative ET trend in wetlands (R < −0.5). These opposing patterns suggest a growing diversion of water toward irrigation at the expense of natural ecosystems. The impact was especially marked during droughts, such as the 2011–2016 period, when precipitation declined by 16%. In wetlands, ET was significantly correlated with precipitation (R > 0.4), highlighting their vulnerability to reduced water inputs. These findings offer crucial insights to support sustainable water management strategies that balance agricultural productivity with the preservation of ecologically valuable systems under mounting climatic and anthropogenic pressures typical of semi-arid Mediterranean environments. Full article
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