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Suitability of Gypsum and Crushed Waste Brick Mix for Stabilization of Weak Subgrade Soil
Assefa Takele Getaneh,
Fekadu Fufa,
Abubekir J. Hussen
Issue:
Volume 6, Issue 4, December 2020
Pages:
111-117
Received:
17 October 2020
Accepted:
29 October 2020
Published:
9 November 2020
Abstract: The strength of the road subgrade for, which mostly causes significant damage to structures such as buildings, roads and bridges due to their swell-shrink effect. In the area of expansive soil and scarcity of suitable construction materials, upgrading the locally available materials is one of best alternative ways. Soil stabilization by adding additives is one of the methods of upgrading substandard materials. Therefore this study assessed the suitability of gypsum and crushed waste brick mix for stabilization of expansive soil to use as a road subgrade preparation. Expansive soil sample was collected from Ilubabora zone and was investigated. Accordingly, expansive soil was stabilized with the mix of crushed waste brick and gypsum material proportion of 0%, 10%, 20%, 30%, 40% and 0%, 2%, 4%, 6%, 8% respectively by weight of the total mix and laboratory tests such as Moisture Content, Grain size distribution, Atterberg Limit, Free Swell, Free Swell Index, Free Swell Ratio, Specific Gravity, Compaction, CBR and CBR-Swell are carried out to assess the alteration in its strength characteristics and index properties. The subgrade material quality improved from A-7-5 to A-2-4 at combination 30% of crushed waste brick and 6% of gypsum with expansive soil. By the addition of stabilizer material to expansive soil the least plasticity index value obtained was 9.030 % and the CBR increased to 10.686% from initial CBR value at the percentage of 30% brick and 6% gypsum. The OMC and MDD was increased to 29.200% and 1.480g/cm3 respectively and the free swell, free swell index, free swell ratio was decreased to 18%, 16.830%, 1.168 respectively and CBR-Swell decreased to 1.370%, from the initial untreated soil test at percentage of 40% crushed waste brick and 8% gypsum mix with expansive soil. Treating expansive soil with the mix of crushed waste brick and gypsum respond and exhibited an improvement on its engineering properties including reduction in plasticity, increased strength and compaction characteristics.
Abstract: The strength of the road subgrade for, which mostly causes significant damage to structures such as buildings, roads and bridges due to their swell-shrink effect. In the area of expansive soil and scarcity of suitable construction materials, upgrading the locally available materials is one of best alternative ways. Soil stabilization by adding addi...
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The Effect of the Change in the Position of Load on the Inclination Angle of Floating Crane
Tran Van Tao,
Nguyen Chien Luy
Issue:
Volume 6, Issue 4, December 2020
Pages:
118-122
Received:
6 November 2020
Accepted:
5 December 2020
Published:
11 December 2020
Abstract: Floating cranes are equipment used for the transport of goods in the ports of Viet Nam. Some of the floating cranes such as the equipment to renovate river cages are also widely used in Vietnam. During operation, the balance of the floating cranes differs from that of the land cranes because of changes in the volume displacement. Besides, the center of the entire structure will vary depending on the location of the goods. For floating cranes the research document is often interested in statically and dynamically stabilizing. Static stability in idle or under load condition is no longer considered by checking whether the stabilization moment is greater than the overturning moment. The dynamic stability was the static balance of the crane is disturbed and behave like certain periodic or unexpected movements on the way to a different balancing position. However, this article refers to the effect of the lifting process on the static equilibrium of floating cranes. The stability of the floating crane is differ from normal ship especially when it is lifting cargo or goods, when the hangging cargo changes its position that will effect to the position of the gavity center of the total weight. In this paper we would like to show the way to calculate hydrostatic and stability of floating crane, especially the changing of inclination angle (heeling and pitching angle) as the hangging goods change its position.
Abstract: Floating cranes are equipment used for the transport of goods in the ports of Viet Nam. Some of the floating cranes such as the equipment to renovate river cages are also widely used in Vietnam. During operation, the balance of the floating cranes differs from that of the land cranes because of changes in the volume displacement. Besides, the cente...
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Combined Teaching Methods of Technical Drawing in Shipbuilding Engineering
Tran Van Tao,
Vo Trong Cang
Issue:
Volume 6, Issue 4, December 2020
Pages:
123-127
Received:
12 November 2020
Accepted:
5 December 2020
Published:
11 December 2020
Abstract: Combining the teaching practice and academic analysis, we explored and studied various teaching methods of "Technical Drawing" to stimulate students' interest in learning and to improve the quality of teaching. It mainly includes a good teacher-student relationship, a combination of various teaching methods, good first-lesson, intensive teaching and process evaluation. According to the characteristics of students and the teaching content, the teaching methods can be scientifically set up to achieve good teaching quality and training results. The initial application results are: use in combination with audio-visual equipment such as 3D images on a computer; perform physical models with a miniature scale from on-paper drawings and especially experience group activities during student practice hours. Through this study, at the Ho Chi Minh city University of Technology, VNU-HCM, faculty of Transportation Engineering, we have tried to find ways to alleviate the difficulties, stimulate students' interest in learning in two directions: 1) enrich the imagination of 3D space and 2) increase the introduction of the production knowledge in the most condensed way. The ultimate goal is to improve teaching efficiency in this subject. On the other hand, the products, models, created by students from the subject are also the good models for the next courses.
Abstract: Combining the teaching practice and academic analysis, we explored and studied various teaching methods of "Technical Drawing" to stimulate students' interest in learning and to improve the quality of teaching. It mainly includes a good teacher-student relationship, a combination of various teaching methods, good first-lesson, intensive teaching an...
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Analysis of Oscillation of Propulsion System on Hovercraft - Theoretical Framework and Review
Issue:
Volume 6, Issue 4, December 2020
Pages:
128-132
Received:
2 August 2020
Accepted:
9 September 2020
Published:
22 December 2020
Abstract: With flexible usability, able to operate both on water and land, hovercraft has a long history of development and is widely used in many countries around the world. In this research, we focus on solving the problem of isolation oscillates when a machine - placed on an isolator - operates the pinwheel to create thrust momentum for hovercraft movements. The main content of the author’s master degree research is to study the oscillator system integrated in the engine structure to significantly reduce the vibration from the main engine and the propeller of the air cushion ship. The study focused on building a calculation model to find the main vibration characteristics of the propulsion system - motor - motor support structure integrated with damping system. Main objective is finding out the parameter values: transmission characteristics, specific frequencies of the air-cushion engine structure and damping system of supporting structure which are able to withstand the best vibration isolation. Based on reviewed literature, simulations and real-world tests (using CALFEM and following simulation models) are being performed to determine the optimal technology parameters. The findings and results continue to contribute to the improvement of engine technology in particular and seaplane engineering technology in general as required by standards and regulations.
Abstract: With flexible usability, able to operate both on water and land, hovercraft has a long history of development and is widely used in many countries around the world. In this research, we focus on solving the problem of isolation oscillates when a machine - placed on an isolator - operates the pinwheel to create thrust momentum for hovercraft movemen...
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