Scientific African最新文献_第6页

A sustainable hybrid cryptographic framework for energy optimization and scalability in blockchain-based e-voting 一种可持续的混合加密框架，用于基于区块链的电子投票中的能源优化和可扩展性

IF 3.3 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2026-03-01 Epub Date: 2026-01-25 DOI: 10.1016/j.sciaf.2026.e03191

Adil Marouan , Morad Badrani , Abderrahim Zannou , Nabil Kannouf , Abdelaziz Chetouani

Electronic voting (e-voting) is increasingly recognized as a viable alternative to traditional paper-based elections, offering automation, transparency, and improved accessibility. However, blockchain-based e-voting frameworks still face critical challenges, notably excessive energy consumption, scalability bottlenecks, and trade-offs between performance and security. This paper proposes a sustainable hybrid cryptographic framework that integrates the Elliptic Curve Digital Signature Algorithm (ECDSA), the Edwards-Curve Digital Signature Algorithm (EdDSA), and Boneh–Lynn–Shacham (BLS) signatures. The proposed design reduces computational and energy overhead through lightweight ballot signing and aggregated verification, while ensuring interoperability with widely deployed blockchain infrastructures. Moreover, the framework incorporates Layer-2 batching within a Proof-of-Stake (PoS) consensus mechanism to minimize transaction costs and latency. Experimental results show that the proposed system reduces per-transaction energy consumption by nearly 50%, doubles transaction throughput from 120 to 250 TPS, and enhances scalability compared to conventional blockchain voting solutions. These findings confirm that hybrid cryptography represents a sustainable and practical pathway towards secure, transparent, and energy-efficient blockchain-based e-voting systems applicable to both institutional and national contexts.

电子投票（e-voting）越来越被认为是传统纸质选举的可行替代方案，具有自动化、透明度和改进的可访问性。然而，基于区块链的电子投票框架仍然面临着严峻的挑战，特别是过度的能源消耗、可扩展性瓶颈以及性能和安全性之间的权衡。本文提出了一种集成椭圆曲线数字签名算法（ECDSA）、爱德华兹曲线数字签名算法（EdDSA）和boneh - lynn - shachham （BLS）签名的可持续混合密码框架。提议的设计通过轻量级选票签名和聚合验证减少了计算和能源开销，同时确保了与广泛部署的区块链基础设施的互操作性。此外，该框架在权益证明（PoS）共识机制中集成了第二层批处理，以最大限度地降低交易成本和延迟。实验结果表明，与传统的区块链投票方案相比，该系统将单笔交易能耗降低了近50%，交易吞吐量从120增加到250 TPS，并增强了可扩展性。这些研究结果证实，混合密码学代表了一条可持续和实用的途径，可以实现安全、透明和节能的基于区块链的电子投票系统，适用于机构和国家背景。

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引用次数: 0

Digitization and the energy paradox: Does broadband adoption increase the electricity intensity of African businesses? 数字化与能源悖论：宽带的采用会增加非洲企业的用电强度吗？

IF 3.3 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2026-03-01 Epub Date: 2025-12-08 DOI: 10.1016/j.sciaf.2025.e03130

Youssef Bouazizi, Mohammed Ghazouani

The digitization of African firms reveals a persistent energy paradox: while digital tools can improve efficiency, they may also intensify electricity demand in contexts marked by infrastructural fragility. This study provides the first multi-country, firm-level assessment of how broadband adoption shapes electricity intensity in Africa, using 10,755 observations from the post COVID World Bank Enterprise Surveys. To address endogeneity, the analysis relies on a causal identification strategy based on Instrumental Variables with the Two Stage Least Squares estimator and the Limited Information Maximum Likelihood estimator. The results show that broadband access increases electricity intensity in the short run, and that conventional estimations underestimate this effect due to measurement error and self-selection. At the same time, broadband adoption significantly promotes product and process innovation, stimulates investment in research and development, and reduces financial obstacles, revealing indirect channels that may support efficiency gains over time. A comprehensive set of robustness and sensitivity tests confirms the stability of these findings across alternative specifications, subsamples, and placebo exercises. By uncovering both the direct and indirect effects of digital integration, this study provides new evidence on the conditions under which connectivity can support Africa’s productive modernization. The results underscore the need for complementary reforms, including reliable electricity infrastructure, strengthened digital and energy capabilities, and expanded access to green and digital finance, in order to transform digitalization into a driver of sustainable energy transitions.

非洲企业的数字化揭示了一个持续存在的能源悖论：虽然数字工具可以提高效率，但在基础设施脆弱的背景下，它们也可能加剧电力需求。本研究利用世界银行新冠肺炎疫情后企业调查的10755项观察结果，首次对宽带采用如何影响非洲电力强度进行了多国、公司层面的评估。为了解决内生性问题，分析依赖于基于工具变量的因果识别策略，使用两阶段最小二乘估计器和有限信息最大似然估计器。结果表明，宽带接入在短期内增加了电力强度，由于测量误差和自我选择，传统的估计低估了这种影响。同时，宽带的采用显著地促进了产品和流程的创新，刺激了对研究和开发的投资，并减少了财务障碍，揭示了可能随着时间的推移支持效率提高的间接渠道。一组全面的稳健性和敏感性测试证实了这些发现在不同规格、子样本和安慰剂练习中的稳定性。通过揭示数字一体化的直接和间接影响，本研究为互联互通支持非洲生产性现代化的条件提供了新的证据。结果强调需要进行配套改革，包括可靠的电力基础设施，加强数字和能源能力，扩大绿色和数字金融的可及性，以将数字化转变为可持续能源转型的驱动力。

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引用次数: 0

A survey of blockchain-based solutions for secure social networks 基于区块链的安全社交网络解决方案调查

IF 3.3 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2026-03-01 Epub Date: 2026-02-03 DOI: 10.1016/j.sciaf.2026.e03233

Fatima Anter , Fatna El Mendili , Nabil Benamar , Nabil Mrani , Mohammed Fattah

Online social networks have become essential platforms for communication and information sharing, yet their centralized architectures expose users to serious privacy, security, and integrity risks. Blockchain technology has emerged as a promising paradigm for addressing these challenges by enabling decentralization, transparency, immutability, and user-centric control over data. This survey aims to systematically examine blockchain-based solutions designed to enhance security and privacy in social networks. Following the PRISMA methodology, we review and analyze peer-reviewed studies published between 2016 and 2025, focusing on blockchain architectures, consensus mechanisms, smart contracts, and their integration with machine learning and deep learning techniques for malicious behavior detection. The survey categorizes existing blockchain-based social networks, compares centralized and decentralized models, and evaluates key trade-offs such as scalability versus security and privacy versus transparency. Additionally, regulatory and governance implications are discussed. The findings indicate that blockchain can significantly improve privacy, security, data integrity, and user empowerment in social networks; however, challenges related to scalability, usability, interoperability, and legal compliance remain. This survey provides a comprehensive overview for researchers and practitioners and identifies open research directions for the secure evolution of social networks.

在线社交网络已经成为交流和信息共享的重要平台，但其集中式架构使用户面临严重的隐私、安全和完整性风险。区块链技术已经成为解决这些挑战的一个很有前途的范例，它支持对数据的去中心化、透明性、不变性和以用户为中心的控制。本调查旨在系统地研究基于区块链的解决方案，旨在增强社交网络的安全性和隐私性。遵循PRISMA方法，我们回顾和分析了2016年至2025年间发表的同行评议研究，重点关注区块链架构、共识机制、智能合约，以及它们与机器学习和深度学习技术的集成，用于恶意行为检测。该调查对现有的基于区块链的社交网络进行了分类，比较了集中式和分散式模型，并评估了可扩展性与安全性、隐私性与透明度等关键权衡。此外，还讨论了法规和治理含义。研究结果表明，区块链可以显著改善社交网络中的隐私、安全、数据完整性和用户授权；然而，与可伸缩性、可用性、互操作性和法律遵从性相关的挑战仍然存在。本调查为研究人员和实践者提供了一个全面的概述，并确定了社交网络安全发展的开放研究方向。

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引用次数: 0

Sequential electrocoagulation–Fungal biotreatment as a pretreatment approach for olive mill wastewater (Fez, Morocco) 顺序电凝-真菌生物处理橄榄厂废水的预处理方法（Fez, Morocco）

IF 3.3 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2026-03-01 Epub Date: 2026-02-05 DOI: 10.1016/j.sciaf.2026.e03241

M.S. Fahmi , H. Bellouk , H. El Harchli , A. El Mahjoub , F. El Khammar , A. Chaouch , F. Khalil

The present study aims to evaluate a preliminary sequential treatment approach combining electrocoagulation (EC) and fungal bioremediation for the purification of olive mill wastewater (OMWW) diluted at a 1:10 ratio. EC, conducted with aluminum electrodes at a current density of 38 A·m⁻² for 4 h, achieved an initial reduction in chemical oxygen demand (COD) from 9520 to 4096 mg·L⁻¹ (56 %) and in phenolic compounds (PC) from 0.55 to 0.28 g·L⁻¹ (49 %). Subsequently, biological treatment with Aspergillus niger for 72 h further decreased COD to 2856 mg·L⁻¹ and PC to 0.137 g·L⁻¹, corresponding to cumulative removals of 70 % and 75 %, respectively. The treated effluent exhibited marked physicochemical improvements, including a decrease in turbidity to 15 NTU, a near-neutral pH (7.1), and a conductivity of 10.0 mS·cm⁻¹. The operational cost of the integrated EC–fungal process was estimated at 1.75 USD·m⁻³, with an associated carbon footprint of 3.4 kg CO₂·m⁻³. These values represent indicative laboratory-scale estimates, requiring validation at the pilot scale with a full accounting of electrode consumption, sludge management, and fungal biomass handling. Overall, the sequential EC–biotreatment constitutes a promising and sustainable pretreatment strategy for high-strength OMWW, facilitating subsequent polishing stages rather than serving as a stand-alone treatment solution.

本研究旨在评价电凝（EC）与真菌生物修复相结合的初步顺序处理方法对1:10稀释橄榄厂废水（OMWW）的净化效果。用铝电极在38 a·m·⁻²的电流密度下进行4小时的EC，初步实现了化学需氧量（COD）从9520毫克·L⁻（56%）减少到4096毫克·L⁻（49%），酚类化合物（PC）从0.55毫克·L⁻（49%）减少到0.28毫克·L⁻（49%）。随后，用黑曲霉进行72小时的生物处理，进一步将COD降低到2856 mg·L⁻1，将PC降低到0.137 g·L⁻1，相当于累计去除量分别为70%和75%。处理后的废水表现出明显的物理化学改善，包括浊度降至15 NTU， pH值接近中性（7.1），电导率为10.0 mS·cm（毒血症）。综合ec -真菌过程的运营成本估计为1.75美元·m⁻³，相关的碳足迹为3.4 kg CO₂·m⁻³。这些值代表了实验室规模的指示性估计，需要在中试规模上进行验证，并充分考虑电极消耗、污泥管理和真菌生物量处理。总的来说，连续ec -生物处理是一种有前途的、可持续的高强度OMWW预处理策略，有利于后续抛光阶段，而不是作为一个独立的处理方案。

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引用次数: 0

State of health estimation for microgrid storage batteries using CNN-BiLSTM-attention-transfer learning 基于cnn - bilstm -注意迁移学习的微电网蓄电池健康状态估计

IF 3.3 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2026-03-01 Epub Date: 2026-02-05 DOI: 10.1016/j.sciaf.2026.e03244

Khalid Errakkas, Mohammed Kissaoui, Rachid Lajouad, Abdelmounime El Magri, Ahmed Khayat, Youness Atifi

This study investigates data-driven state-of-health forecasting for second-life lithium-ion battery modules operated under long-term residential microgrid duty cycles. While CNN–recurrent–attention models are widely used in laboratory SOH studies, reliable field deployment is limited by distribution shift and by evaluation leakage when overlapped time windows are used across train and test. We address these issues using a two-stage domain-adaptation framework: a CNN–BiLSTM multi-head attention model is first pre-trained on NASA laboratory aging data to learn general degradation representations, then selectively adapted to microgrid data by freezing the CNN feature extractor and the lower BiLSTM while fine-tuning the upper temporal and attention/regression layers. For microgrid scenarios, we enforce a strict chronological split using date-labelled quarter folders and construct sliding windows only after splitting, preventing raw-sample overlap between train/validation/test. Experiments show low error on NASA cells (average RMSE ≈ 1.24% and MAE ≈ 0.98%) and robust transfer performance on three microgrid scenarios with RMSE below 3.5% (PV: 2.76%, PV-TOU: 2.34%, TOU: 3.12%). These results indicate that selective freezing reduces target-data requirements while maintaining generalization under real duty-cycle variability, supporting practical SOH monitoring and maintenance planning for second-life battery energy storage systems.

本研究调查了在长期住宅微电网占空比下运行的二次寿命锂离子电池模块的数据驱动的健康状态预测。虽然cnn -循环关注模型在实验室SOH研究中得到了广泛的应用，但当列车和测试之间使用重叠的时间窗时，由于分布偏移和评估泄漏，限制了可靠的现场部署。我们使用两阶段域自适应框架来解决这些问题：首先在NASA实验室老化数据上预训练CNN - BiLSTM多头部注意力模型，以学习一般退化表示，然后通过冻结CNN特征提取器和较低的BiLSTM，同时微调上层时间层和注意力/回归层，选择性地适应微电网数据。对于微电网场景，我们使用日期标记的四分之一文件夹强制执行严格的按时间顺序拆分，并仅在拆分后构建滑动窗口，以防止训练/验证/测试之间的原始样本重叠。实验表明，在NASA电池上的误差较低（平均RMSE≈1.24%,MAE≈0.98%），在RMSE低于3.5% （PV: 2.76%, PV-TOU: 2.34%, TOU: 3.12%）的3种微电网场景下，传输性能稳健。这些结果表明，选择性冻结降低了对目标数据的要求，同时在实际占空比可变性下保持了通用性，为二次寿命电池储能系统的实际SOH监测和维护计划提供了支持。

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引用次数: 0

Marketed surplus of head cabbage in Northwest Ethiopia: Evidence from an instrumental variable regression analysis 埃塞俄比亚西北部大白菜的市场盈余：来自工具变量回归分析的证据

IF 3.3 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2026-03-01 Epub Date: 2026-02-03 DOI: 10.1016/j.sciaf.2026.e03236

Abera Ayalew, Yohannes Girma

Head cabbage plays a vital role in supporting household livelihoods in Ethiopia. This study aimed to examine the main factors affecting the marketed surplus of head cabbage, along with the production and marketing challenges faced by producers, and available opportunities. A multistage sampling procedure was used, starting with the purposive selection of four major cabbage producing districts, followed by the random selection of 364 producers from eight kebeles. Data analysis was carried out in STATA 17 using linear and instrumental variable regression methods. Due to suspect of endogeneity problem, human labor, seed, horse labor, distance to development center, and credit access were taken as instrumental variables and determinants of marketed surplus were assessed through 2SLS estimation. The 2SLS results revealed that total production, cooperative membership, farming experience, family size, access to market information, and participation in off/non-farm activities significantly influenced the marketed surplus of head cabbage. Favorable agroecological conditions, irrigation access, high market demand, and the presence of multipurpose cooperatives were identified as key opportunities supporting production and marketing of cabbage. Conversely, weak market linkages, pest and disease problems, seasonal production patterns, and limited risk management options were major constraints. Therefore, strengthening cooperatives, advisory services, and market linkages is crucial to promote sustainable head cabbage production and the marketed surplus.

在埃塞俄比亚，大白菜在支持家庭生计方面发挥着至关重要的作用。本研究旨在探讨影响大白菜市场盈余的主要因素，以及生产者面临的产销挑战和可利用的机会。采用多阶段抽样程序，首先有目的地选择4个大白菜产区，然后从8个大白菜产区随机选择364个生产者。在stata17中使用线性和工具变量回归方法进行数据分析。考虑到内生问题，以人力、种子、马、发展中心距离和信贷获取为工具变量，采用2SLS估计方法评估市场剩余的决定因素。2SLS结果显示，总产量、合作社成员、耕作经验、家庭规模、市场信息获取和非农活动参与显著影响大白菜的市场剩余。有利的农业生态条件、灌溉渠道、高市场需求和多用途合作社的存在被确定为支持白菜生产和销售的关键机会。相反，市场联系薄弱、病虫害问题、季节性生产模式和有限的风险管理办法是主要制约因素。因此，加强合作社、咨询服务和市场联系对于促进白菜的可持续生产和市场剩余至关重要。

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引用次数: 0

Item Response Theory for trait assessment in randomized item pool for computer based test 计算机测试随机题库中特质评价的项目反应理论

IF 3.3 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2026-03-01 Epub Date: 2026-01-31 DOI: 10.1016/j.sciaf.2026.e03226

Rhydal Esi Eghan, Edward Osei-Sarpong, Gaston Edem Awashie, Reindorf Nartey Borkor, Evans Yaokumah, Aditta Abigail N’ganomah

The rapid adoption of computer-based examinations (CBE) has raised concerns regarding fairness and reliability in assessing student performance. This study examines randomized test item fairness to test takers’ traits in CBE through the application of Item Response Theory (IRT), with a focus on the two-parameter logistic (2PL) model. Data were collected from 500 level 100 undergraduate students who responded to ten Algebra test items. Raw scores were dichotomized into binary outcomes and analyzed to estimate each item’s difficulty level

(b)

, item’s discrimination power

(a)

, student ability (latent trait)

(θ)

and overall test performance. The estimated item discrimination parameter ranged from 0.87 to 2.14, while the item difficulty parameter estimate ranged from 0.26 to 1.91. These estimates indicated moderate to strong discriminatory power across most test items and its effectiveness between low and high ability examinees, as well as a balanced mix of less difficult, moderately difficult, and highly difficult items, respectively. The test-level analyses using the Test Characteristic Curve (TCC) and Test Information Curve (TIC) showed that the test was most reliable for candidates with average ability levels, clustered at latent traits of

0 \leq θ \leq 2

. The item-fit metric evaluation utilizing the S-

X^{2}

statistic ranging from 1.182 to 5.304, with corresponding p-values between 0.505 and 0.978 above the chosen significance level (

α = 0.05

), and RMSEA values close to 0.000 highlighted eight out of the ten items within the acceptable model fit criteria. This implied that although the majority of examinees receive fair and reliable measurements from the randomized test, some items may need to be revised in order to increase measurement accuracy and equity. The study shows how IRT may be used practically for trait assessment and test item fairness evaluation in computer-based exams.

计算机考试的迅速普及引起了人们对评估学生表现的公平性和可靠性的关注。本研究运用项目反应理论（IRT）考察了CBE随机测试项目对被试特质的公平性，重点研究了双参数逻辑模型（2PL）。数据收集自500名100级本科生，他们回答了10个代数测试项目。将原始分数二分类为二值结果，并进行分析，以估计每个项目的难度(b)、项目的辨别力(a)、学生的能力（潜在特质）（θ）和整体测试成绩。项目辨别参数估计范围为0.87 ~ 2.14，项目难度参数估计范围为0.26 ~ 1.91。这些估计表明，在大多数测试项目中，中等到强烈的歧视性力量，以及在低能力和高能力考生之间的有效性，以及分别在低难度、中等难度和高难度项目之间的平衡混合。采用测试特征曲线（TCC）和测试信息曲线（TIC）进行测试水平分析，结果表明，该测试对能力水平平均的候选人最可靠，聚集在0≤θ≤2的潜在性状上。利用S-X2统计量进行项目拟合度量评价，范围从1.182到5.304，相应的p值在0.505到0.978之间，高于所选的显著性水平（α=0.05）， RMSEA值接近0.000，突出了10个项目中8个在可接受的模型拟合标准内。这意味着，尽管大多数考生从随机测试中获得了公平可靠的测量结果，但有些项目可能需要修改，以提高测量的准确性和公平性。本研究揭示了IRT在计算机考试中特质评价和试题公平性评价的可行性。

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引用次数: 0

Rural residents' climate change perception and its influence on climate-smart business adoption using technology acceptance model: A study in Lahijan County, Iran 基于技术接受模型的农村居民气候变化感知及其对气候智能型企业采用的影响——基于伊朗拉希詹县的研究

IF 3.3 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2026-03-01 Epub Date: 2026-02-13 DOI: 10.1016/j.sciaf.2026.e03256

Ali Akbar Barati, Hossein Shabanali Fami, Seyed Erfan Hosseini, Mohadeshe Aliakbari

Rural areas heavily rely on natural resources. This makes their residents and businesses vulnerable to the climate change and its impacts. Addressing these challenges requires reducing harmful climate effects, promoting adaptation, and improving rural-environmental relationships for sustainable development. This study aims to explore how rural residents perceive climate change influence their adoption of climate-smart rural businesses in northern Iran. Data were collected using a questionnaire from a sample include 175 rural residents selected from a population of 23,668. The partial least squares modeling method was employed to data analysis. Results showed that tangible natural impacts, such as rising soil salinity and poorer groundwater quality, most strongly shaped villagers’ perceptions of climate change. However, residents exhibited low trust in climate-smart rural businesses as effective solutions, indicating a confidence gap. Attitudes toward climate-smart rural businesses as the most important factor affecting adoption intention. The study highlights the need for policies that address trust gaps, enhance perceived usefulness and ease of climate-smart rural businesses to shift attitudes toward climate-smart rural businesses, and resolve urgent environmental challenges. It seems, integrating local perspectives with ecological and social realities is vital to align rural livelihoods with sustainability goals and ensure effective climate adaptation.

农村严重依赖自然资源。这使得他们的居民和企业容易受到气候变化及其影响的影响。应对这些挑战需要减少有害的气候影响，促进适应，改善农村与环境的关系，以实现可持续发展。本研究旨在探讨伊朗北部农村居民如何看待气候变化影响他们采用气候智能型农村企业。数据是通过问卷调查收集的，样本包括从23,668人口中选出的175名农村居民。采用偏最小二乘建模方法对数据进行分析。结果显示，土壤盐度上升和地下水质量下降等有形的自然影响最强烈地影响了村民对气候变化的看法。然而，居民对气候智慧型农村企业作为有效解决方案的信任度较低，表明存在信心差距。对气候智能型农村企业的态度是影响采用意愿的最重要因素。该研究强调需要制定政策，解决信任差距问题，提高气候智慧型农村企业的实用性和便利性，从而转变对气候智慧型农村企业的态度，并解决紧迫的环境挑战。要使农村生计与可持续发展目标保持一致，确保有效适应气候变化，将当地视角与生态和社会现实相结合似乎至关重要。

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引用次数: 0

Kinetics, isotherm, thermodynamics, and DFT studies for the simultaneous adsorption of two anionic dyes using MgAl layered double hydroxide MgAl层状双氢氧化物同时吸附两种阴离子染料的动力学、等温线、热力学和DFT研究

IF 3.3 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2026-03-01 Epub Date: 2026-02-12 DOI: 10.1016/j.sciaf.2026.e03248

Chaymae Hmimen , Alae Elabed , Mohamed Amine Djebbi , Abdesslem Ben Haj Amara , Saad Ibnsouda Koraichi , Soumya Elabed

Efficient removal of synthetic dyes from wastewater is crucial to mitigate their environmental impact. In this study, MgAl-layered double hydroxides (MgAl LDHs) with Mg²⁺:Al³⁺ ratios of 2:1, 3:1, and 4:1 and two interlayer anions (Cl⁻ and CO₃²⁻) were synthesized by co-precipitation and characterized by XRD, FTIR, BET, SEM, and TEM. Batch adsorption experiments optimized key variables, with best performance at pH 5, 120 min contact time, and 0.02 g adsorbent dosage. The Mg₃Al–Cl sample showed the highest capacities–even when both dyes were present and interfering with each other–reaching 166.62 mg·g⁻¹ for methyl orange (MO) and 123.35 mg·g⁻¹ for congo red (CR). Kinetic data were best described by the pseudo-second-order model, and isotherms fitted the Langmuir equation. Thermodynamic parameters indicated a feasible, spontaneous, and endothermic process. The interlayer anion critically affected performance: chloride-intercalated LDHs outperformed carbonate-intercalated ones under identical conditions, consistent with differences in anion exchange and interaction strength with the galleries. The material retained >80 % capacity after five regeneration cycles. Density functional theory (DFT) supported the experiments, showing adsorption governed by electrostatic attraction, hydrogen bonding, surface complexation, and n–π stacking, and clarifying how both the Mg²⁺:Al³⁺ ratio and the interlayer anion identity tune adsorption efficiency. The originality of this work lies in a combined experimental–DFT framework that co-optimizes cation ratio and interlayer anion to predict and enhance simultaneous removal of multiple anionic dyes.

有效地去除废水中的合成染料对减轻其对环境的影响至关重要。本研究通过共沉淀法合成了Mg²+:Al³+的比例为2:1、3:1和4:1，层间两个阴离子（Cl⁻和CO₃²⁻）的MgAl层状双氢氧化物（MgAl LDHs），并用XRD、FTIR、BET、SEM和TEM对其进行了表征。批量吸附实验对关键变量进行优化，在pH为5、接触时间为120 min、吸附剂用量为0.02 g时吸附效果最佳。Mg₃Al-Cl样品显示出最高的容量——即使两种染料都存在并且相互干扰——甲基橙（MO）的容量达到166.62 Mg·g⁻¹，刚果红（CR）的容量达到123.35 Mg·g⁻¹。动力学数据最好用拟二阶模型来描述，等温线符合Langmuir方程。热力学参数表明这是一个可行的、自发的、吸热的过程。层间阴离子严重影响了性能：在相同条件下，氯化物插层的LDHs性能优于碳酸盐插层的LDHs，这与阴离子交换和与廊相互作用强度的差异一致。经过5次再生循环后，该材料仍保持80%的容量。密度泛函理论（DFT）支持了实验，表明吸附受静电吸引、氢键、表面络合和n -π堆叠的控制，并阐明了Mg 2 +:Al³+的比值和层间阴离子的同一性如何影响吸附效率。这项工作的独创性在于结合实验- dft框架，共同优化阳离子比例和层间阴离子，以预测和增强同时去除多种阴离子染料。

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引用次数: 0

Modeling urban expansions and its environmental effects in Arba Minch City, Southern Ethiopia using GIS, remote sensing, and Shannon entropy 基于GIS、遥感和Shannon熵的埃塞俄比亚南部Arba Minch市城市扩张及其环境影响模型

IF 3.3 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African

Pub Date : 2026-03-01 Epub Date: 2026-02-10 DOI: 10.1016/j.sciaf.2026.e03251

Betelhem Zemenu , Ephrem Getahun , Sisay Alemayehu , Muralitharan Jothimani

Rapid urban expansion in developing countries has intensified land use and land cover (LULC) changes, resulting in significant environmental impacts that challenge sustainable urban development. Although Arba Minch City is one of the fastest-growing urban centers in southern Ethiopia, comprehensive studies integrating advanced geospatial techniques and quantitative models to assess urban expansion patterns and their environmental implications remain limited. This study analyzed urban expansion in Arba Minch, southern Ethiopia, between 2013 and 2023 using Geographic Information Systems (GIS), remote sensing, and the Shannon entropy model. The supervised classification, utilizing the maximum likelihood algorithm on Landsat 8 OLI/TIRS imagery, achieved high overall accuracies of 93% in 2013 and 94% in 2023. Additionally, Kappa coefficients of 0.91 for both years indicate a strong level of classification reliability. LULC change analysis revealed a notable increase in built-up areas by 1262.34 hectares, primarily at the expense of vegetation (-929.34 ha) and bare land (-359.19 ha). During 2013–2023, vegetation indices (NDVI) declined from an average of 0.31 to 0.2, while built-up index (NDBI) values increased from a mean of -0.17 to -0.09. Land Surface Temperature (LST) rose from 18.7 °C - 35.6 °C in 2013 to 19.6 °C - 44.0 °C in 2023, reflecting intensification of the urban heat island effect. The Shannon entropy analysis indicates dispersed patterns of urban growth, particularly toward the northwest (NW) and northeast (NE) directions. Furthermore, the urban expansion intensity index (UEII) uncovered a high level of urban growth intensity (UEII=1.64). The findings indicate substantial spatio-temporal changes in LULC and urban growth during 2013–2023. The study concludes that rapid and dispersed urban growth in Arba Minch City has led to considerable environmental degradation. It recommends the implementation of sustainable urban planning strategies, protection of remaining vegetation, and integration of geospatial tools into urban management policies to balance future urban development with environmental conservation.

发展中国家的快速城市扩张加剧了土地利用和土地覆盖（LULC）的变化，造成了重大的环境影响，挑战了城市的可持续发展。尽管阿尔巴明奇市是埃塞俄比亚南部发展最快的城市中心之一，但整合先进地理空间技术和定量模型来评估城市扩张模式及其环境影响的综合研究仍然有限。本研究利用地理信息系统（GIS）、遥感和Shannon熵模型分析了2013年至2023年埃塞俄比亚南部Arba Minch的城市扩张。监督分类利用Landsat 8 OLI/TIRS图像上的最大似然算法，在2013年和2023年的总体准确率分别达到93%和94%。此外，两年的Kappa系数均为0.91，表明分类信度较高。LULC变化分析显示，建成区面积增加了1262.34公顷，主要是植被（-929.34公顷）和裸地（-359.19公顷）的损失。2013-2023年，植被指数（NDVI）从平均0.31下降到0.2，建筑指数（NDBI）从平均-0.17上升到-0.09。地表温度（LST）从2013年的18.7 ~ 35.6℃上升到2023年的19.6 ~ 44.0℃，反映出城市热岛效应加剧。香农熵分析表明，城市增长呈分散趋势，特别是向西北（NW）和东北（NE）方向发展。此外，城市扩张强度指数（UEII）揭示了高水平的城市增长强度（UEII=1.64）。研究结果表明，2013-2023年期间，中国城市土地利用和土地利用价值与城市增长发生了显著的时空变化。该研究的结论是，Arba Minch市快速而分散的城市增长导致了相当大的环境退化。报告建议实施可持续城市规划战略，保护剩余植被，并将地理空间工具纳入城市管理政策，以平衡未来城市发展与环境保护。

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