The search for efficient and versatile structural elements, leads to the fabrication of I-joists (6.5 cm × 18.5 cm × 600 cm (width × depth × length) with glue-laminated bamboo (Guada angustifolia) ...The search for efficient and versatile structural elements, leads to the fabrication of I-joists (6.5 cm × 18.5 cm × 600 cm (width × depth × length) with glue-laminated bamboo (Guada angustifolia) in the flanges and Gmelina arborea 12-mm structural plywood in the web. The results showed a modulus of rupture (MOR) of 39.45 MPa and an effective modulus of elasticity (MOE) of 17.05 GPa. Shearing in the glue line was 5.95 MPa and the lamination strength was 6.45 MPa. Structural design values averaged 9.43 MPa for bending and 4.72 MPa in shear according to Costa Rican structural standards. Both resistance value (flexure and shear) were considered satisfactory for structural proposes and I-joists fabricated with bamboo and G. arborea plywood are comparable with the Andean classification group “C” structural grade. The use of this I-joist was also shown in roofing and flooring systems. This beam can be used in allowable spans from 2 to 4 m in span for flooring systems and from 5 to 7 m for roofing applications.展开更多
Jaén is one of the most important cities in the northern highlands of Peru due to its strategic location,commerce,and agricultural activities.Jaén has more than 185 thousand inhabitants,of which 48%live in r...Jaén is one of the most important cities in the northern highlands of Peru due to its strategic location,commerce,and agricultural activities.Jaén has more than 185 thousand inhabitants,of which 48%live in rural areas,representing approximately 31 thousand rural housing.This research aims to determine the types of rural housing in Jaen,showing the possible variations and architectural manifestations due to the territorial and cultural characteristics.A field observation sheet has been used to study the rural dwellings of populated centres previously classified by altitudinal regions.The results show six architectural types of rural housing classified into two groups:"rural-residential housing"and"rural-agricultural housing"'These architectural types are generally located near water sources,within agricultural plots,and on hillsides.The architectural program is characterised by agricultural activity and family composition,which has grown over time.The most commonly used construction systems are"pirca"and"quincha"',using natural materials such as"ichu"and adobe.There is also evidence of cultural traditions rooted in the construction,such as"cambio de fuerzas""paracaico",and"minga".Therefore,the relevance of Jaen's rural housing is its geographical reading of the territory through the architectural and cultural legacy of these buildings.展开更多
Given an involution in a group G, it can be extended in various ways to an involution in the group ring RG, where R is a ring, not necessarily commutative. In this paper nonlinear extensions are considered and necessa...Given an involution in a group G, it can be extended in various ways to an involution in the group ring RG, where R is a ring, not necessarily commutative. In this paper nonlinear extensions are considered and necessary and sufficient conditions are given on the group G, its involution, the ring R and the extension for the set of skew-symmetric elements to be commutative and for it to be anticommutative.展开更多
文摘The search for efficient and versatile structural elements, leads to the fabrication of I-joists (6.5 cm × 18.5 cm × 600 cm (width × depth × length) with glue-laminated bamboo (Guada angustifolia) in the flanges and Gmelina arborea 12-mm structural plywood in the web. The results showed a modulus of rupture (MOR) of 39.45 MPa and an effective modulus of elasticity (MOE) of 17.05 GPa. Shearing in the glue line was 5.95 MPa and the lamination strength was 6.45 MPa. Structural design values averaged 9.43 MPa for bending and 4.72 MPa in shear according to Costa Rican structural standards. Both resistance value (flexure and shear) were considered satisfactory for structural proposes and I-joists fabricated with bamboo and G. arborea plywood are comparable with the Andean classification group “C” structural grade. The use of this I-joist was also shown in roofing and flooring systems. This beam can be used in allowable spans from 2 to 4 m in span for flooring systems and from 5 to 7 m for roofing applications.
文摘Jaén is one of the most important cities in the northern highlands of Peru due to its strategic location,commerce,and agricultural activities.Jaén has more than 185 thousand inhabitants,of which 48%live in rural areas,representing approximately 31 thousand rural housing.This research aims to determine the types of rural housing in Jaen,showing the possible variations and architectural manifestations due to the territorial and cultural characteristics.A field observation sheet has been used to study the rural dwellings of populated centres previously classified by altitudinal regions.The results show six architectural types of rural housing classified into two groups:"rural-residential housing"and"rural-agricultural housing"'These architectural types are generally located near water sources,within agricultural plots,and on hillsides.The architectural program is characterised by agricultural activity and family composition,which has grown over time.The most commonly used construction systems are"pirca"and"quincha"',using natural materials such as"ichu"and adobe.There is also evidence of cultural traditions rooted in the construction,such as"cambio de fuerzas""paracaico",and"minga".Therefore,the relevance of Jaen's rural housing is its geographical reading of the territory through the architectural and cultural legacy of these buildings.
文摘Given an involution in a group G, it can be extended in various ways to an involution in the group ring RG, where R is a ring, not necessarily commutative. In this paper nonlinear extensions are considered and necessary and sufficient conditions are given on the group G, its involution, the ring R and the extension for the set of skew-symmetric elements to be commutative and for it to be anticommutative.
