Current environmental and eco-design issues require the use of environmentally friendly materials. These make up a large share of the building materials market. Natural fibers are already used in various types of mate...Current environmental and eco-design issues require the use of environmentally friendly materials. These make up a large share of the building materials market. Natural fibers are already used in various types of materials, such as plastics, concrete and lime-based products. They exhibit different attributes like the right combination of mechanical, thermal and acoustic properties, allowing these types of materials to be used for different applications. The main disadvantage associated with plaster is its fragility, especially under mechanical stress. Therefore, it becomes interesting to study different methods that could improve the mechanical properties of plaster. The addition of fibers to the plaster to obtain a composite material is already recognized as a means of improving the behavior of the product, in particular after the rupture of the matrix. The aim of this work was to study the effects of the addition of natural fibers from the stem of Cola lepidota (CL), on the physical properties and the mechanical behavior of the composite matrix. This study highlights the effects of fiber size and volume fraction. It has been shown that the mass of composites decreases as the percentage and length of fibers increases. The mechanical properties of composite materials are also discussed. Even at low addition rates, CL stem fibers achieved slightly higher values of flexural properties.展开更多
Road safety is still an important issue with road accidents among the leading causes of death accounting for more than 1.2 million fatalities and 50 million injuries globally per year. Of these casualties, speeding is...Road safety is still an important issue with road accidents among the leading causes of death accounting for more than 1.2 million fatalities and 50 million injuries globally per year. Of these casualties, speeding is a substantial contributing factor. Nowadays, speed reduction is mainly achieved through speed law enforcement measures. The review is aimed at examining the different enforcement approaches used to control and monitor excessive speeds on highways at large and particularly in Cameroon. A systematic search was performed in Science Direct, Elsevier, google scholar, scientific research, and Springer, ResearchGate, Scopus, and PubMed databases. Furthermore, references of selected articles were reviewed to maximize the rate of articles found. The details of the research articles were generated using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) flow chart. The results show that of 658 retried articles, duplicates of 458 were excluded and 200 were screened. A total of 61 and 40 articles were screened from abstract and full pdf text respectively. Finally, 15 relevant studies were included in the study. The review revealed that the included articles on speed enforcement on the highway were limited to sanctioning defaulters for fine payments.展开更多
文摘Current environmental and eco-design issues require the use of environmentally friendly materials. These make up a large share of the building materials market. Natural fibers are already used in various types of materials, such as plastics, concrete and lime-based products. They exhibit different attributes like the right combination of mechanical, thermal and acoustic properties, allowing these types of materials to be used for different applications. The main disadvantage associated with plaster is its fragility, especially under mechanical stress. Therefore, it becomes interesting to study different methods that could improve the mechanical properties of plaster. The addition of fibers to the plaster to obtain a composite material is already recognized as a means of improving the behavior of the product, in particular after the rupture of the matrix. The aim of this work was to study the effects of the addition of natural fibers from the stem of Cola lepidota (CL), on the physical properties and the mechanical behavior of the composite matrix. This study highlights the effects of fiber size and volume fraction. It has been shown that the mass of composites decreases as the percentage and length of fibers increases. The mechanical properties of composite materials are also discussed. Even at low addition rates, CL stem fibers achieved slightly higher values of flexural properties.
文摘Road safety is still an important issue with road accidents among the leading causes of death accounting for more than 1.2 million fatalities and 50 million injuries globally per year. Of these casualties, speeding is a substantial contributing factor. Nowadays, speed reduction is mainly achieved through speed law enforcement measures. The review is aimed at examining the different enforcement approaches used to control and monitor excessive speeds on highways at large and particularly in Cameroon. A systematic search was performed in Science Direct, Elsevier, google scholar, scientific research, and Springer, ResearchGate, Scopus, and PubMed databases. Furthermore, references of selected articles were reviewed to maximize the rate of articles found. The details of the research articles were generated using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) flow chart. The results show that of 658 retried articles, duplicates of 458 were excluded and 200 were screened. A total of 61 and 40 articles were screened from abstract and full pdf text respectively. Finally, 15 relevant studies were included in the study. The review revealed that the included articles on speed enforcement on the highway were limited to sanctioning defaulters for fine payments.
