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Correlation of Bending Test Varying the Length Between Supports to Determine Longitudinal Modulus of Elasticity
Edson Fernando Castanheira Rodrigues,
André Luis Christoforo
Issue:
Volume 8, Issue 2, March 2019
Pages:
21-24
Received:
14 May 2019
Accepted:
19 June 2019
Published:
29 June 2019
Abstract: The large amount of wood in Brazil related to the numerous uses of this material stimulates many studies to be carried out in order to use this raw material increasingly in a rational and adequate way. Compared with concrete and steel, wood presents an excellent relation between mechanical strength and its mass, beauty, low energy consumption for its processing, good thermal insulation and easy workability. In order to make the best use of wood, this work proposes to study the correlation between the values of the longitudinal modulus of elasticity (E) obtained in the 3-point bending test with a 14H and 21H (H = height of cross-sectional area) of specimen measurement between the supports. The data were analyzed through linear regression analysis, thus, three correlations were calculated between values from 14H of span length to the other 21H of span length in the test for a particular correlation of each hardwood species (Peroba Rosa and Eucalyptus Tereticornis) and the third one was generalized for the use in more hardwood species. Thus, the correlation of the longitudinal modulus of elasticity for the species of the hardwood group was possible for: Peroba Rosa (Aspidosperma polyneuron) with 35 specimens and Eucalyptus Tereticornis (Eucalyptus tereticornis) with 33 specimens.
Abstract: The large amount of wood in Brazil related to the numerous uses of this material stimulates many studies to be carried out in order to use this raw material increasingly in a rational and adequate way. Compared with concrete and steel, wood presents an excellent relation between mechanical strength and its mass, beauty, low energy consumption for i...
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Selective Synthesis and Characterization of Single Walled Carbon Nanotubes (11, 8)
Danlami Umar Zuru,
Bala Hassan,
Muhammad Nuraddeen Bui,
Aliyu Sa’ad BK,
Aliyu Jabbo Bunzah
Issue:
Volume 8, Issue 2, March 2019
Pages:
25-29
Received:
2 April 2019
Accepted:
9 May 2019
Published:
4 July 2019
Abstract: Single walled carbon nanotubes (SWCNTs) are attractive in the nanotechnology industry where they find applications in the field of pharmacy and medicine due to high surface area capable of transporting drugs and vaccines to active sites; for fabrication of energy storing devices due to excellent electrical conductivity and accessible pore sizes; in transport for the fabrication of strong and lightweight vehicle and aircraft parts and in composite materials to enhance physical and chemical properties such as toughness, durability, conductivity and strength. The most efficient and cost effective method of obtaining these precious materials is the Chemical Vapour Deposition (CVD), however, obtaining SWCNTs of desired electronic type via this method, has remained a global challenge for over 20 years. This has limited the availability of these products in the global research and technological industries, contributing to the problem of lack of raw materials to sustain them. In this report, metallic SWCNTs (11, 8) are selectively synthesized via chemical vapor deposition (CVD) method, by the pyrolysis of C6H14/N2 feedstock on Fe2O3/Al2O3 catalyst matrix. Catalyst design and preparation was achieved by correlating the numerical magnitudes of chiral index (n, m) of the desired SWCNTs with mole fractions of metal/support, respectively. Field emission scanning electron microscopy analysis reveals densely entangled tubular bundles, while high resolution transmission electron microscopy confirms rigid arrangements of SWCNTs in the bundles. Values of the radial breathing modes, diameter and energy band gaps of the sample obtained from Raman analysis conforms to that of SWCNTs (11, 8), established via Extended Tight Binding (ETB) model. Outcome of this report suggested that our catalyst design and preparation may help alleviate the stated global challenge.
Abstract: Single walled carbon nanotubes (SWCNTs) are attractive in the nanotechnology industry where they find applications in the field of pharmacy and medicine due to high surface area capable of transporting drugs and vaccines to active sites; for fabrication of energy storing devices due to excellent electrical conductivity and accessible pore sizes; in...
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Two Different Loading Directions to Determine the Shear and Longitudinal Modulus of Elasticity
Edson Fernando Castanheira Rodrigues,
André Luis Christoforo
Issue:
Volume 8, Issue 2, March 2019
Pages:
30-34
Received:
7 May 2019
Accepted:
6 June 2019
Published:
4 July 2019
Abstract: The large-scale abundance of wood in Brazil combined with the advantages of its use stimulate many studies to be encouraged in order to make use of this raw material in a more optimized and adequate form. Compared with concrete and steel, wood presents an excellent relation between mechanical strength and its mass, beauty, low energy consumption for its processing, good thermal insulation and easy workability. Objectifying the best use of wood, this work proposes that the equivalence between longitudinal and transversal modulus of elasticity values with radial (ELR; GLT) and tangential load application (ELT; GLR) in the 3 and 4-point bending tests used for their determinations. The test of equivalence used in the analysis of the results for the modulus of elasticity was the Tukey’s test, by which the statistical equivalence between values of longitudinal (ELR x ELT) and transversal (GLT x GLR) modulus of elasticity with the radial and tangential load application, respectively. It was concluded that for the species of the hardwood group: Peroba Rosa (Aspidosperma polyneuron) with 35 specimens, Eucalyptus Tereticornis (Eucalyptus tereticornis) with 33 specimens, Jatobá (Hymenaea courbaril) with 28 specimens and Canafístula Peltophorum dubium) with 12 test specimens, tested in this work, there was no significant influence of the direction change of the loads on the values of the calculated modulus of elasticity.
Abstract: The large-scale abundance of wood in Brazil combined with the advantages of its use stimulate many studies to be encouraged in order to make use of this raw material in a more optimized and adequate form. Compared with concrete and steel, wood presents an excellent relation between mechanical strength and its mass, beauty, low energy consumption fo...
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