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Engineering geological investigation of Gololcha dam for evaluation of leakage and abutment slope stability, Eastern Ethiopia 为评估埃塞俄比亚东部 Gololcha 大坝的渗漏和坝基边坡稳定性而进行的工程地质调查
IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES Pub Date : 2024-09-18 DOI: 10.1016/j.sciaf.2024.e02381
The Ethiopian economy is primarily dependent on agriculture, making the construction of water harvesting facilities, such as dams, crucial for improving the productivity of this sector. The ongoing construction of the Gololcha dam on the Kurkura River located in Eastern Ethiopia aims to enhance irrigation schemes in the region. However, the dam site's complex geological and structural conditions pose challenges related to leakage and slope instability. Hence, this study focuses on addressing the abutment slope stability and leakage condition of this dam. This study employed kinematic analysis and the Limit Equilibrium Method (LEM) to assess slope stability. Additionally, engineering geological mapping, discontinuity surveys, seismic refraction tomography (SRT), and in-situ permeability testing were used to evaluate the leakage condition of the dam site. Notably, the permeability and SRT survey results identified potential leakage zones to the depth of 35, 30, and 35 m at the left, right, and central foundations of the dam, respectively. The kinematic method revealed one planar and two wedge modes of failure in the slope section covered by slightly weathered and fractured basalt rock at the right abutment. Further stability analysis of these two modes of failures via LEM analysis indicated slope instability under saturated conditions, emphasizing the role of pore water pressure. Furthermore, LEM modeling was directly utilized using the Slide 6.0 software to analyze the slope stability condition of the left abutment of the dam. This modeling also uncovered instability under saturated conditions. Based on the study findings, this study recommended curtain grouting to address potential leakage, as well as slope flattening and removing unstable rock wedges and loose material to stabilize unstable slope sections.
埃塞俄比亚的经济主要依赖农业,因此建造水坝等集水设施对于提高农业生产率至关重要。正在埃塞俄比亚东部库尔库拉河上修建的 Gololcha 大坝旨在加强该地区的灌溉计划。然而,坝址复杂的地质和结构条件带来了与渗漏和斜坡不稳定性有关的挑战。因此,本研究重点关注该大坝的坝基边坡稳定性和渗漏状况。本研究采用运动分析和极限平衡法(LEM)来评估边坡稳定性。此外,还采用了工程地质测绘、不连续性勘测、地震折射断层扫描(SRT)和原位渗透性测试来评估坝址的渗漏状况。值得注意的是,渗透性和 SRT 勘测结果表明,大坝左、右和中央地基的潜在渗漏区深度分别为 35 米、30 米和 35 米。运动学方法显示,在右侧坝基被轻微风化和断裂的玄武岩覆盖的斜坡部分,存在一种平面溃坝模式和两种楔形溃坝模式。通过 LEM 分析法对这两种破坏模式进行的进一步稳定性分析表明,边坡在饱和条件下不稳定,强调了孔隙水压力的作用。此外,还使用 Slide 6.0 软件直接利用 LEM 模型分析了大坝左侧支墩的边坡稳定性状况。该模型还揭示了饱和条件下的不稳定性。根据研究结果,本研究建议采用帷幕灌浆法来解决潜在的渗漏问题,并对斜坡进行平整,清除不稳定的岩楔和松散材料,以稳定不稳定的斜坡部分。
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引用次数: 0
Multi-criteria decision-based hybrid energy selection system using CRITIC weighted CODAS approach 使用 CRITIC 加权 CODAS 方法的基于多标准决策的混合能源选择系统
IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES Pub Date : 2024-09-18 DOI: 10.1016/j.sciaf.2024.e02372
A complex and multicriteria decision making (MCDM) problem arises in a bid to select the most appropriate hybrid energy system among several combinations in distributed electricity generation as it involves conflicting criteria that must be simultaneously considered. In this work, Criteria Importance Through Intercriteria Correlation (CRITIC) along with Combinative Distance-Based Assessment (CODAS) was employed to select a suitable hybrid energy system combination for water pumping from four conflicting alternatives of Biomass-Battery (S1), PV-Battery (S2), PV-Biomass (S3), and PV-Biomass-Battery (S4) by objective weight estimation. This was followed by a confirmation by the Additive Ratio Assessment (ARAS) method for the solution. The results presented show that CRITIC method reveals 0.275, 0.224, 0.248, and 0.252 as different weights of the four alternatives of S1, S2, S3, and S4, respectively. The ranking results reveal S4 as the best alternative based on an assessment score of 0.4693. The same hybrid system was confirmed by ARAS based on overall performance and degree of utility of 0.287697 and 0.823716, respectively.
在分布式发电过程中,要从多个组合中选择最合适的混合能源系统,会出现一个复杂的多标准决策(MCDM)问题,因为它涉及到必须同时考虑的相互冲突的标准。在这项工作中,采用了 "通过标准间相关性确定标准重要性"(CRITIC)和 "基于组合距离的评估"(CODAS),通过客观权重估算,从生物质-电池(S1)、光伏-电池(S2)、光伏-生物质(S3)和光伏-生物质-电池(S4)这四个相互冲突的备选方案中,选择一个合适的混合能源系统组合用于抽水。随后,采用加法比率评估(ARAS)方法对解决方案进行了确认。结果显示,CRITIC 方法显示 S1、S2、S3 和 S4 四个备选方案的不同权重分别为 0.275、0.224、0.248 和 0.252。排序结果显示,S4 是最佳选择,评估得分为 0.4693。基于 0.287697 和 0.823716 的总体性能和实用程度,ARAS 确认了相同的混合系统。
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引用次数: 0
The impact of river sand mining and waste management on the Volta Lake: A case study of Asutsuare 河砂开采和废物管理对沃尔特湖的影响:阿苏图阿雷案例研究
IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES Pub Date : 2024-09-18 DOI: 10.1016/j.sciaf.2024.e02359
The safety of drinking water is becoming more crucial as the world's population is increasing and anthropogenic activities which pollute water resources are intensifying. This study was carried out between June and August of 2022 to determine the physicochemical and microbial parameters of the Volta Lake at Asutsuare due to sand mining activities and to evaluate how well coconut husk biochar could remove these contaminants. Water samples were taken from one meter below the surface at the upstream, midstream (sand mining site) and downstream once a week for three months. Water samples from the midstream were passed through a coconut husk biochar column to determine its ability to remove pollutants in the water samples. Compared to the upstream, there was a significant difference (p < 0.05) in colour, turbidity, iron, manganese, biochemical oxygen demand, chemical oxygen demand, total coliform and total suspended solids from the water sampled from the midstream and downstream sites. Moreover, these values also exceeded the WHO guidelines. There were no significant differences (p > 0.05) between the midstream, the upstream and downstream sampling sites for the following parameters: zinc, lead, copper, conductivity, TDS, temperature, faecal coliform, Escherichia coli and pH. Biochar from coconut husk was used once and seems to be a highly effective sorbent for removing pollutants from water samples (>70 % removal efficiency).
随着世界人口的不断增长和人类活动对水资源污染的加剧,饮用水的安全变得越来越重要。这项研究是在 2022 年 6 月至 8 月期间进行的,目的是确定阿苏特苏阿雷的沃尔特湖因采砂活动而产生的物理化学和微生物参数,并评估椰糠生物炭去除这些污染物的效果。水样从上游、中游(采沙场)和下游水面下一米处采集,每周一次,持续三个月。中游的水样通过椰壳生物炭柱,以确定其去除水样中污染物的能力。与上游相比,中游和下游的水样在色度、浑浊度、铁、锰、生化需氧量、化学需氧量、总大肠菌群和总悬浮固体方面存在显著差异(p < 0.05)。此外,这些数值也超过了世界卫生组织的指导标准。中游、上游和下游采样点的以下参数无明显差异(p > 0.05):锌、铅、铜、电导率、总悬浮固体含量、温度、粪大肠菌群、大肠杆菌和 pH 值。椰子壳生物炭被使用过一次,似乎是去除水样中污染物的高效吸附剂(去除率为 70%)。
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引用次数: 0
Corrigendum to: A combined administration of GABA agonist and L-histidine synergistically alleviates obesity-induced neuro-lipotoxicity and distorted metabolic transcriptome [Scientific African 24 (2024) e02177] 更正:联合使用GABA激动剂和L-组氨酸可协同缓解肥胖引起的神经脂肪毒性和代谢转录组扭曲 [Scientific African 24 (2024) e02177]
IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES Pub Date : 2024-09-18 DOI: 10.1016/j.sciaf.2024.e02347
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引用次数: 0
Revisiting the effect of information and communication technologies on employment growth in Ghana: The role of enterprise formality 重新审视信息和通信技术对加纳就业增长的影响:企业正规化的作用
IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES Pub Date : 2024-09-18 DOI: 10.1016/j.sciaf.2024.e02394
The employment effect of information and communication technologies (ICT) on firm performance remains a critical topic for policy and academic research. However, our understanding of the ICT-employment growth relationship in both informal and formal sectors in developing countries remains limited. Based on repeated cross-sectional data collected in 2013 and 2015 on 483 Ghanaian manufacturing enterprises and estimating a Feasible Generalised Least Squares (FGLS) regression model, the findings show that access to the internet leads to employment growth in enterprises, while the adoption of mobile phone technologies reduces the number of workers in enterprises. The positive effect of internet access on employment growth tends to be greater in enterprises with a higher degree of formality, while informal enterprises appear to remain small in terms of employment by using internet technology. We discuss these findings and their implications for digital technology policy in developing countries.
信息和通信技术(ICT)对企业绩效的就业影响仍然是政策和学术研究的一个重要课题。然而,我们对发展中国家非正规和正规部门的 ICT 与就业增长关系的了解仍然有限。基于 2013 年和 2015 年收集的 483 家加纳制造业企业的重复横截面数据,并通过可行的广义最小二乘法(FGLS)回归模型进行估计,研究结果表明,互联网的接入会导致企业的就业增长,而手机技术的采用则会减少企业的工人数量。在正规程度较高的企业中,互联网接入对就业增长的积极影响往往更大,而非正规企业通过使用互联网技术似乎仍能保持较小的就业规模。我们将讨论这些发现及其对发展中国家数字技术政策的影响。
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引用次数: 0
Geographically weighted logistic regression model for identifying risk factors for malaria infection among under-5 children in Ghana 用于确定加纳 5 岁以下儿童感染疟疾风险因素的地理加权逻辑回归模型
IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES Pub Date : 2024-09-17 DOI: 10.1016/j.sciaf.2024.e02398

Malaria remains a significant public health challenge globally, particularly affecting children under-5 years of age due to their underdeveloped immune systems. Identifying the risk factors associated with malaria infection in this vulnerable group is crucial for improving policy formulation and creating effective training programs. However, there is limited information on how the relationship between malaria risk and associated factors varies across different regions, especially among children in Ghana. This is important because understanding these spatial variations can enhance targeted interventions including area remediation and resource allocation. To address this gap, a geographically weighted logistic regression (GWLR) model was developed to identify spatially varying risk factors for malaria infection among children under five in Ghana. The model was built on the premise that the relationship between malaria and potential risk factors is not uniform across geographic areas. Data from the Ghana Malaria Indicator Survey collected through the demographic and health survey program were used for analysis. The study found that the GWLR model fit the data better than the conventional binary logistic regression (BLR) model, based on the information criterion used and mode evaluation metrics. The results indicated that risk factors for malaria such as a child's age, anaemia status, dwellings sprayed, place of residence, electricity access, NHIS (National Health Insurance Scheme) coverage, age of the household head, and household wealth index, were non-stationary across the study area. These findings underscore the importance of spatially tailored interventions to reduce malaria risk in children under-5. The results contribute to the body of literature on malaria risk factors and provide valuable insights for Ghana's national malaria control policies, potentially enhancing the effectiveness of future public health strategies.

疟疾仍然是全球公共卫生面临的一项重大挑战,由于 5 岁以下儿童的免疫系统发育不全,他们受到的影响尤为严重。确定这一弱势群体感染疟疾的相关风险因素,对于改进政策制定和创建有效的培训计划至关重要。然而,关于疟疾风险与相关因素之间的关系在不同地区,尤其是在加纳儿童中如何变化的信息十分有限。这一点非常重要,因为了解这些空间变化可以加强包括地区补救和资源分配在内的有针对性的干预措施。为了弥补这一不足,我们建立了一个地理加权逻辑回归(GWLR)模型,以确定加纳五岁以下儿童感染疟疾的空间变化风险因素。建立该模型的前提是,疟疾与潜在风险因素之间的关系在不同地理区域并不一致。通过人口与健康调查计划收集的加纳疟疾指标调查数据被用于分析。研究发现,根据所使用的信息标准和模式评价指标,GWLR 模型比传统的二元逻辑回归(BLR)模型更适合数据。研究结果表明,儿童年龄、贫血状况、喷洒过药物的住所、居住地、用电情况、NHIS(国家健康保险计划)覆盖率、户主年龄和家庭财富指数等疟疾风险因素在整个研究区域内是非稳态的。这些发现强调了针对不同空间的干预措施对降低五岁以下儿童疟疾风险的重要性。这些结果为有关疟疾风险因素的文献做出了贡献,并为加纳国家疟疾控制政策提供了有价值的见解,有可能提高未来公共卫生战略的有效性。
{"title":"Geographically weighted logistic regression model for identifying risk factors for malaria infection among under-5 children in Ghana","authors":"","doi":"10.1016/j.sciaf.2024.e02398","DOIUrl":"10.1016/j.sciaf.2024.e02398","url":null,"abstract":"<div><p>Malaria remains a significant public health challenge globally, particularly affecting children under-5 years of age due to their underdeveloped immune systems. Identifying the risk factors associated with malaria infection in this vulnerable group is crucial for improving policy formulation and creating effective training programs. However, there is limited information on how the relationship between malaria risk and associated factors varies across different regions, especially among children in Ghana. This is important because understanding these spatial variations can enhance targeted interventions including area remediation and resource allocation. To address this gap, a geographically weighted logistic regression (GWLR) model was developed to identify spatially varying risk factors for malaria infection among children under five in Ghana. The model was built on the premise that the relationship between malaria and potential risk factors is not uniform across geographic areas. Data from the Ghana Malaria Indicator Survey collected through the demographic and health survey program were used for analysis. The study found that the GWLR model fit the data better than the conventional binary logistic regression (BLR) model, based on the information criterion used and mode evaluation metrics. The results indicated that risk factors for malaria such as a child's age, anaemia status, dwellings sprayed, place of residence, electricity access, NHIS (National Health Insurance Scheme) coverage, age of the household head, and household wealth index, were non-stationary across the study area. These findings underscore the importance of spatially tailored interventions to reduce malaria risk in children under-5. The results contribute to the body of literature on malaria risk factors and provide valuable insights for Ghana's national malaria control policies, potentially enhancing the effectiveness of future public health strategies.</p></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2468227624003405/pdfft?md5=dd29c1d93658b4ac613783235b2f858e&pid=1-s2.0-S2468227624003405-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142274002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Development of machine learning-based standalone GUI application for predicting hydraulic conductivity and compaction parameters of lateritic soils 开发基于机器学习的独立 GUI 应用程序,用于预测红土的导水性和压实参数
IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES Pub Date : 2024-09-17 DOI: 10.1016/j.sciaf.2024.e02393
Hydraulic conductivity and compaction parameters are the key considerations in selecting lateritic soils for engineering construction. Nevertheless, the complexity and high cost of the required tests have driven many contractors and field engineers to skip them, resulting in a succession of engineering structure failures. To overcome this limitation, this study developed machine learning-based standalone GUI application to predict lateritic soils’ hydraulic conductivity (K), maximum dry density (MDD) and optimum moisture content (OMC) from indices including specific gravity, liquid limit, plasticity index, linear shrinkage and fine content. To achieve this goal, the geotechnical properties of three hundred samples, collected using grid sampling method from thirty different lateritic deposits in southwestern Nigeria, were evaluated through laboratory tests. The test results were used to train predictive models using artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS) and Gaussian process regression (GPR). The models’ performance was compared using coefficient of determination (R2), root mean squared error (RMSE), mean absolute percentage error (MAPE) and mean absolute error (MAE). Based on these performance metrics, ANN demonstrated the best performance (R2 = 0.9835, 0.9797, 0.9999; RMSE = 7.938, 0.252, 2.09E-08; MAPE = 0.288, 1.114, 1.587; MAE = 5.432, 0.169, 1.1E-08) for MDD, OMC and K, respectively, followed by GPR and then ANFIS. Thus, the ANN models were selected and embedded in a standalone GUI application to enhance easy and quick prediction of lateritic soils’ MDD, OMC and K. The validity of the ANN-based standalone GUI application was demonstrated by comparing it favorably to notable regression-based models in the literature.
导水性和压实参数是选择红土用于工程建设的关键因素。然而,所需测试的复杂性和高成本促使许多承包商和现场工程师跳过这些测试,导致工程结构接连失败。为克服这一局限性,本研究开发了基于机器学习的独立 GUI 应用程序,可根据比重、液限、塑性指数、线性收缩和细粒含量等指标预测红土的导水性(K)、最大干密度(MDD)和最佳含水量(OMC)。为实现这一目标,通过实验室测试评估了从尼日利亚西南部 30 个不同红土矿床中采用网格取样法收集的 300 个样本的岩土特性。测试结果用于使用人工神经网络 (ANN)、自适应神经模糊推理系统 (ANFIS) 和高斯过程回归 (GPR) 训练预测模型。使用判定系数 (R2)、均方根误差 (RMSE)、平均绝对百分比误差 (MAPE) 和平均绝对误差 (MAE) 对模型的性能进行了比较。根据这些性能指标,ANN 对 MDD、OMC 和 K 的性能最好(R2 = 0.9835、0.9797、0.9999;RMSE = 7.938、0.252、2.09E-08;MAPE = 0.288、1.114、1.587;MAE = 5.432、0.169、1.1E-08),其次是 GPR,然后是 ANFIS。因此,选择了 ANN 模型并将其嵌入到独立的 GUI 应用程序中,以提高红土土壤 MDD、OMC 和 K 预测的简便性和快速性。
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引用次数: 0
Anti-aging effect of mustard and flax seed oils based nanoemulsion gel on aged rat skin through antioxidant and anti-inflammatory activity 基于芥末和亚麻籽油的纳米乳液凝胶通过抗氧化和抗炎活性对老化大鼠皮肤的抗衰老作用
IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES Pub Date : 2024-09-17 DOI: 10.1016/j.sciaf.2024.e02369

Skin aging is a common issue that is linked to changes in skin physiology, hydration, and barrier function. Dietary fatty acids (FA), particularly poly-unsaturated fatty acids (PUFA), can influence skin characteristics. It is reported that a deficiency of fatty acids in the skin is associated with skin aging. Therefore, the goal of the current study is to evaluate the antiaging effect of flaxseed oil or mustard oil-based nanoemulsion gel rich in fatty acids such as omega 3 on D-galactose-induced skin aging. N-hexane was used to extract the oils of black mustard and flax seed from their seeds, and the oils' fatty acid composition was then determined. A full factorial design was created to assess the impact of three variables: oil type, oil concentration, and S:Cos ratio, on various responses: globule size, zeta potential, and emulsification time of the self-nanoemulsifying system. Additionally, the polydispersity index, transmittance percentage, refractive index, cloud point, and viscosity were also estimated. TEM of the optimized formulations revealed a spherical form of oil globules with nanosize. The values for the zeta potential ranged from -12 to -34.2 mV. The optimized formulations were incorporated into a hydroxypropyl methyl cellulose solution to form a nanoemulsion gel. Skin aging was induced using the D-galactose model, and the impact of topical skin application of the optimized formulation gels on different biomarkers such as amino acids, B5, oxidative stress markers, inflammatory mediators and histopathological examination was evaluated. The results showed a considerable improvement in the evaluated parameters of the treated groups when compared to the untreated D-galactose group. The findings suggest that the nanoemulsifying system utilizing high doses of fixed plant oils could serve as a promising vehicle for enhancing skin rejuvenation. Flaxseed oil formulation showed greater potential compared to mustard oil formulation as skin antiaging.

皮肤老化是一个常见问题,与皮肤生理、水合作用和屏障功能的变化有关。膳食脂肪酸(FA),尤其是多元不饱和脂肪酸(PUFA),会影响皮肤的特性。据报道,皮肤中脂肪酸的缺乏与皮肤老化有关。因此,本研究的目的是评估亚麻籽油或芥子油基纳米乳凝胶(富含欧米伽 3 等脂肪酸)对 D-半乳糖诱导的皮肤老化的抗衰老作用。使用正己烷从黑芥子和亚麻籽的种子中提取油脂,然后测定油脂的脂肪酸组成。采用全因子设计来评估油的类型、油的浓度和 S:Cos 比率这三个变量对自纳米乳化体系的球形大小、ZETA电位和乳化时间等各种反应的影响。此外,还估算了多分散指数、透射比、折射率、浊点和粘度。优化配方的 TEM 显示油球呈纳米级球形。zeta 电位值介于 -12 至 -34.2 mV 之间。将优化配方加入羟丙基甲基纤维素溶液中形成纳米乳液凝胶。使用 D-半乳糖模型诱导皮肤老化,并评估皮肤局部使用优化配方凝胶对不同生物标志物(如氨基酸、B5、氧化应激标志物、炎症介质和组织病理学检查)的影响。结果表明,与未处理的 D-半乳糖组相比,处理组的评估参数有了显著改善。研究结果表明,利用高剂量固定植物油的纳米乳化系统可以作为一种很有前景的载体,用于增强皮肤年轻化。亚麻籽油配方与芥子油配方相比,在皮肤抗衰老方面显示出更大的潜力。
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引用次数: 0
Uncovering service gaps and patterns in smallholder dairy production systems: A data mining approach 发现小农奶牛生产系统中的服务差距和模式:数据挖掘方法
IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES Pub Date : 2024-09-17 DOI: 10.1016/j.sciaf.2024.e02392

Traditional clustering algorithms have often been used to categorize farmers but tend to overlook the underlying reasons for these groupings. Typically, clusters are formed based on common metrics such as dispersal and centrality, which provide limited insights into the relationships among key attributes. This study introduces an innovative approach using pattern and association rules analysis to better understand the characteristics of dairy production clusters. Focusing on Tanzanian smallholder farmers, the research moves beyond identifying clusters to uncovering the hidden relationships within them. Through pattern analysis, the study logically examines the behavioral mechanisms that define these clusters, highlighting service gaps that, if addressed, could enhance smallholder dairy farmers' productivity. Frequent patterns with support ranging from 57 % to 93 % and confidence levels between 85 % and 100 % were identified, revealing critical challenges faced by these farmers. For instance, farmers using Artificial Insemination—typically younger or new entrants—face constraints related to farm size, land holdings, fodder production, lack of farmer groups, and insufficient formal training in dairy care. Meanwhile, seasoned farmers deal more with institutional barriers such as limited access to marketplaces, extension services, and distant water sources. The study highlights the diverse challenges faced by different farmer groups and provides strategic recommendations for improving dairy productivity. Enhancing access to formal training, improving fodder production, supporting the formation of farmer groups, and addressing institutional barriers are key actions that could help Tanzanian smallholder dairy farmers increase milk yield and overall productivity.

传统的聚类算法通常用于对农民进行分类,但往往会忽略这些分组的根本原因。通常情况下,聚类是根据分散性和中心性等常见指标形成的,而这些指标对关键属性之间的关系提供的洞察力有限。本研究引入了一种创新方法,利用模式和关联规则分析来更好地了解乳制品生产集群的特征。该研究以坦桑尼亚小农为重点,不仅要识别集群,还要揭示集群中隐藏的关系。通过模式分析,该研究顺理成章地考察了界定这些集群的行为机制,突出了服务差距,如果加以解决,可以提高小农奶农的生产率。研究确定了支持率在 57 % 到 93 % 之间、置信度在 85 % 到 100 % 之间的常见模式,揭示了这些奶农面临的关键挑战。例如,使用人工授精的牧场主--通常是年轻牧场主或新加入的牧场主--面临着与牧场规模、土地保有量、饲料生产、缺乏牧场主团体以及奶牛护理方面的正规培训不足有关的制约因素。与此同时,经验丰富的牧场主则面临更多的制度性障碍,如进入市场的机会有限、推广服务和水源遥远等。该研究强调了不同农民群体面临的各种挑战,并提出了提高奶业生产率的战略建议。增加获得正规培训的机会、提高饲料产量、支持农民团体的形成以及解决制度性障碍是帮助坦桑尼亚小农奶农提高牛奶产量和整体生产率的关键行动。
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引用次数: 0
Efficiency enhancement through hybrid integration of five-phase PMSG with photovoltaic generator with Vienna rectifier 通过五相 PMSG 与带维也纳整流器的光伏发电机的混合集成提高效率
IF 2.7 Q2 MULTIDISCIPLINARY SCIENCES Pub Date : 2024-09-17 DOI: 10.1016/j.sciaf.2024.e02376

This paper explores the hybridization of a five-phase permanent magnet synchronous generator integrated with a photovoltaic generator. The hybrid configuration aims to maximize overall energy production and optimize system performance. The distinctive feature of the proposed structure lies in the parallel connection of a five-phase machine with a Vienna rectifier and a PV system directly linked to the inverter. This novel integration, associated with the designed controllers, significantly reduces switching losses, enhancing system efficiency and demonstrating robust performance despite the complexities associated with the control strategy. The paper delves into the design and evaluation of this nonlinear hybrid system, shedding light on its potential to contribute to sustainable and efficient renewable energy solutions.

本文探讨了五相永磁同步发电机与光伏发电机的混合集成。该混合配置旨在最大限度地提高整体发电量并优化系统性能。拟议结构的显著特点在于五相机器与维也纳整流器的并联,以及光伏系统与逆变器的直接连接。这种新颖的集成与设计的控制器相结合,大大降低了开关损耗,提高了系统效率,尽管控制策略非常复杂,但仍能表现出稳健的性能。本文深入探讨了这一非线性混合系统的设计和评估,揭示了其为可持续、高效的可再生能源解决方案做出贡献的潜力。
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引用次数: 0
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