Road construction in Africa is faced with a shortage of quality materials, leading to delays and increased costs. Traditional materials, such as clay soils of the bar soil type, have inadequate properties for pavement...Road construction in Africa is faced with a shortage of quality materials, leading to delays and increased costs. Traditional materials, such as clay soils of the bar soil type, have inadequate properties for pavement sub-base layers, particularly in terms of bearing capacity. This study explores a composite material combining bar soil and bamboo fibers to improve the mechanical performance of bar soil, offering a sustainable and cost-effective solution. The Tori-Bossito bar soil was characterised by particle size analysis, Atterberg limits, Proctor compaction tests and the California Bearing Ratio (CBR). The results show that this material is a class A2 sandy-clay soil with a CBR of 18, which is insufficient for foundation layers requiring a CBR of over 30. To improve its performance, Sèmè-Kpodji bamboo fibers, 30 to 100 microns in diameter and 3 to 5 cm long, were incorporated at rates of 0.9% to 2.7%. The optimum mix, with 2.4% fiber, has a CBR of 35, a dry density of 1.92 t/m3 and a moisture content of 12.4%. This reinforced material is suitable as a base course for low-traffic roadways.展开更多
火箭基组合循环(Rocket Based Combined Cycle,RBCC)推进系统是极具发展前景的组合动力方案,而模态转换阶段是RBCC发动机工作的关键环节,关系到整个推进系统的成败和效率。RBCC发动机的不同工作模态具有显著的分类特征,重点总结了引射/...火箭基组合循环(Rocket Based Combined Cycle,RBCC)推进系统是极具发展前景的组合动力方案,而模态转换阶段是RBCC发动机工作的关键环节,关系到整个推进系统的成败和效率。RBCC发动机的不同工作模态具有显著的分类特征,重点总结了引射/亚燃与亚燃/超燃两个关键转换阶段,综述相关特性与机理的研究进展,汇总实验与数值模拟方面的研究成果。与双模态超燃冲压发动机相比,RBCC发动机由于内含火箭射流,在模态平稳转换控制上具备优势。结合以等离子体为代表的新型多场燃烧耦合控制方式,RBCC发动机成为了当前超声速燃烧流动控制的研究热点。在总结相关进展的基础上,对未来的模态过渡研究提出了建议。展开更多
Every year,the State of Qatar generates about 400,000 tons of steel slag and another 500,000 tons of gravel as a result of steel manufacturing and washing sand,respectively.The two materials(by-products)are not fully ...Every year,the State of Qatar generates about 400,000 tons of steel slag and another 500,000 tons of gravel as a result of steel manufacturing and washing sand,respectively.The two materials(by-products)are not fully utilized to their best market values.At the same time,infrastructural renewal will take place in Qatar over the next ten years,and there will be a greater demand for aggregates and other construction materials as the country suffers from the availability of good aggregates.This paper presents results obtained on the use of steel slag,gravel and gabbro(control)in HMAC(hot mix asphalt concrete)paving mixtures and road bases and sub-bases.Tests were conducted in accordance with QCS-2010(Qatar Construction Specifications)and results were compared with QCS requirements for aggregates used in these applications.Based on the data obtained in this work,steel slag and gravel aggregates have a promising potential to be used in HMAC paving mixtures on Qatar’s roads,whether in asphalt base and asphalt wearing courses or as unbound aggregates in the base and sub-base pavement structure.展开更多
Background: Evidence-based practice (EBP) is vital for high-quality patient care, yet its implementation among physiotherapists in sub-Saharan Africa (SSA) faces significant challenges. This scoping review explores th...Background: Evidence-based practice (EBP) is vital for high-quality patient care, yet its implementation among physiotherapists in sub-Saharan Africa (SSA) faces significant challenges. This scoping review explores the barriers and facilitators of EBP in this region. Objectives: To identify barriers and facilitators of EBP at individual, organisational, and extra organisational levels among physiotherapists in SSA. Methods: A comprehensive literature search was conducted across PubMed, Sabinet, BioMed Central, and Google Scholar. Seven studies from Ghana, Nigeria, Cameroon, Benin, Kenya, Zimbabwe and South Africa met the inclusion criteria. Results: Key barriers at the practitioner level included lack of time, insufficient knowledge of EBP, limited access to information resources, and inadequate research skills. Facilitators comprised positive attitudes toward EBP and a desire for further knowledge. At the organisational level, resource unavailability emerged as a major barrier. Notably, no studies addressed extra organisational factors. Conclusion: This review highlights critical barriers and facilitators of EBP among SSA physiotherapists and emphasises the need for further research on extra organisational influences. Addressing systemic challenges is essential for enhancing physiotherapist engagement in EBP, ultimately improving patient care and outcomes in sub-Saharan Africa.展开更多
文摘Road construction in Africa is faced with a shortage of quality materials, leading to delays and increased costs. Traditional materials, such as clay soils of the bar soil type, have inadequate properties for pavement sub-base layers, particularly in terms of bearing capacity. This study explores a composite material combining bar soil and bamboo fibers to improve the mechanical performance of bar soil, offering a sustainable and cost-effective solution. The Tori-Bossito bar soil was characterised by particle size analysis, Atterberg limits, Proctor compaction tests and the California Bearing Ratio (CBR). The results show that this material is a class A2 sandy-clay soil with a CBR of 18, which is insufficient for foundation layers requiring a CBR of over 30. To improve its performance, Sèmè-Kpodji bamboo fibers, 30 to 100 microns in diameter and 3 to 5 cm long, were incorporated at rates of 0.9% to 2.7%. The optimum mix, with 2.4% fiber, has a CBR of 35, a dry density of 1.92 t/m3 and a moisture content of 12.4%. This reinforced material is suitable as a base course for low-traffic roadways.
文摘火箭基组合循环(Rocket Based Combined Cycle,RBCC)推进系统是极具发展前景的组合动力方案,而模态转换阶段是RBCC发动机工作的关键环节,关系到整个推进系统的成败和效率。RBCC发动机的不同工作模态具有显著的分类特征,重点总结了引射/亚燃与亚燃/超燃两个关键转换阶段,综述相关特性与机理的研究进展,汇总实验与数值模拟方面的研究成果。与双模态超燃冲压发动机相比,RBCC发动机由于内含火箭射流,在模态平稳转换控制上具备优势。结合以等离子体为代表的新型多场燃烧耦合控制方式,RBCC发动机成为了当前超声速燃烧流动控制的研究热点。在总结相关进展的基础上,对未来的模态过渡研究提出了建议。
文摘Every year,the State of Qatar generates about 400,000 tons of steel slag and another 500,000 tons of gravel as a result of steel manufacturing and washing sand,respectively.The two materials(by-products)are not fully utilized to their best market values.At the same time,infrastructural renewal will take place in Qatar over the next ten years,and there will be a greater demand for aggregates and other construction materials as the country suffers from the availability of good aggregates.This paper presents results obtained on the use of steel slag,gravel and gabbro(control)in HMAC(hot mix asphalt concrete)paving mixtures and road bases and sub-bases.Tests were conducted in accordance with QCS-2010(Qatar Construction Specifications)and results were compared with QCS requirements for aggregates used in these applications.Based on the data obtained in this work,steel slag and gravel aggregates have a promising potential to be used in HMAC paving mixtures on Qatar’s roads,whether in asphalt base and asphalt wearing courses or as unbound aggregates in the base and sub-base pavement structure.
文摘Background: Evidence-based practice (EBP) is vital for high-quality patient care, yet its implementation among physiotherapists in sub-Saharan Africa (SSA) faces significant challenges. This scoping review explores the barriers and facilitators of EBP in this region. Objectives: To identify barriers and facilitators of EBP at individual, organisational, and extra organisational levels among physiotherapists in SSA. Methods: A comprehensive literature search was conducted across PubMed, Sabinet, BioMed Central, and Google Scholar. Seven studies from Ghana, Nigeria, Cameroon, Benin, Kenya, Zimbabwe and South Africa met the inclusion criteria. Results: Key barriers at the practitioner level included lack of time, insufficient knowledge of EBP, limited access to information resources, and inadequate research skills. Facilitators comprised positive attitudes toward EBP and a desire for further knowledge. At the organisational level, resource unavailability emerged as a major barrier. Notably, no studies addressed extra organisational factors. Conclusion: This review highlights critical barriers and facilitators of EBP among SSA physiotherapists and emphasises the need for further research on extra organisational influences. Addressing systemic challenges is essential for enhancing physiotherapist engagement in EBP, ultimately improving patient care and outcomes in sub-Saharan Africa.
