5,073 research outputs found
Electromagnetic properties of the Delta(1232) and decuplet baryons in the self-consistent SU(3) chiral quark-soliton model
We examine the electromagnetic properties of the Delta(1232) resonance within
the self-consistent chiral quark-soliton model. In particular we present the
Delta form factors of the vector-current GE0, GE2 and GM1 for a
momentum-transfer range of . We apply the
symmetry-conserving quantization of the soliton and take 1/N_c rotational
corrections into account. Values for the magnetic moments of all decuplet
baryons as well as for the N-Delta transition are given. Special interest is
also given to the electric quadrupole moment of the Delta.Comment: 24 pages, 8 figure
An analytical approach for pull-out behavior of TRM-strengthened rammed earth elements
Rammed earth constructions, beyond being largely spread in the built heritage, are known for their high seismic vulnerability, which results from high self-weight, lack of box behavior and low mechanical properties of the material. Hence, to mitigate this seismic vulnerability, a compatible textile reinforced mortar (TRM) is here proposed as a strengthening solution, because of its reduced mass and high ductility. The few research about the structural behavior of TRM-strengthened rammed earth elements addresses the global behavior, overlooking the local behavior of the system. An analytical approach to infer the bond stress-slip relationship following the direct boundary problem is proposed. Based on a previous series of pull-out tests, an adhesion-friction constitutive law is portrayed considering also a damage model that considers the degradation of the reinforcing fibers due to friction.This work was partly financed by FEDER funds through the Operational Programme Competitiveness Factors (COMPETE 2020) and by national funds through the Foundation for Science and Technology (FCT) within the scope of project SafEarth - PTDC/ECM-EST/2777/2014 (POCI-01-0145-FEDER-016737). The support from grant SFRH/BD/131006/2017 is also acknowledged
Application Of Optical Method In Measuring Mechanical Vibrations In A Cantilever Beam
The pertinent literature discloses a family of optical profile measuring techniques highlighting the moire methods. The Moire technique is based on the interference of two superimposed optical grids which produce fringe patterns which can be processed to analyze the DYNAMIC MEASUREMENT IN MATERIALS mechanical behavior. The goal of this research is to experimentally determine the mechanical displacement of a slim cantilever beam by means of Moire technique with Phase Shift. Photomechanical experimental arrangement included a digital camera, a multimedia projector and a PC. The occurrence of oscillations has been adequately analyzed. The results showed data from which useful information can withdraw, being of great importance to support agricultural machinery projects and development.371849
Effectiveness of a TRM solution for rammed earth under in-plane cyclic loads
To evaluate the effectiveness of a TRM-strengthening solution for rammed earth walls subjected to in-plane cyclic loads, an experimental program was conducted on a strengthened mock-up previously damaged. The experimental results are discussed in comparison with the previous unstrengthened model in terms of cracking pattern, damage identification, displacements, base shear coefficient, stiffness degradation, and energy dissipation; in addition, simplified equivalent linear and bi-linear systems are inferred to assess the performance. The outcomes highlighted the effectiveness of the TRM solution in improving the in-plane shear capacity, the ductility and the dissipated energy of the mock-up.This work was partly financed by FEDER funds through the Operational Programme Competitiveness Factors (COMPETE 2020) and by national funds through the Foundation for Science and Technology (FCT) within the scope of project SafEarth - PTDC/ECM-EST/2777/2014 (POCI-01-0145-FEDER-016737). The support from grants SFRH/BD/131006/2017 and SFRH/BPD/97082/2013 is also acknowledged. Acknowledgments are addressed to the Laboratory of Structures (LEST) of the University of Minho and to João Bernardino, Lda. and TERRACRUA - Construções Ecológicas Unipessoal, Lda for building the rammed earth model
Direct radiation estimates from horizontal global irradiance values
One of the main factors determining the economic feasibility of a solar thermal power plant is the
availability of direct radiation at the plant site. During last years, two Central Receiver Power Plants (Solgas and
Colon Solar) have been proposed in the South West of Spain (Huelva). For this area only global solar radiation data
are available in a historical representative database. Based on an 11 years radiation database gathered at a nearby
location, distance less than 100 km, 12 correlations, (one per month), between Mt and Md have been obtained. Solar
global radiation data from the power plant site and generated correlations have allowed the "construction" of a Direct
Radiation Design year that has been used both to design the solar plant heliostat field and receiver and to estimate
annual energy produced by the solar plant
Performance of rammed earth subjected to in-plane cyclic displacement
Rammed earth structures are worldwide spread, both as architectural heritage and new constructions. Yet, rammed earth buildings present, in general, high seismic vulnerability. Despite the several studies conducted on the mechanical characterisation of rammed earth and on the numerical modelling of structural elements built with this material, further in-plane cyclic tests on rammed earth sub-assemblies are required to characterise their hysteretic behaviour. In this framework, an experimental program was conducted where cyclic in-plane tests were performed on a large-scale rammed earth wall. The geometry of the wall was defined to represent a sub-assembly commonly found in rammed earth dwellings from Alentejo (Southern Portugal). The wall was subjected to cyclic shear displacements with increasing amplitude, imposed in both positive and negative directions. To detect the dynamic properties of the wall and to assess the development of the structural damage, dynamic identification tests were conducted along the experimental programme. The results are analysed in terms of crack pattern, dynamic properties, displacement capacity, base shear performance and stiffness degradation. Further discussion is led on the dissipated energy, while a bi-linear and linear equivalent systems are proposed as simplified modelling approach. In conclusion, degradation of structural capacity was observed due to cyclic loads, while adequate energy dissipation and base shear coefficient were obtained.This work was partly financed by FEDER funds through the Operational Programme Competitiveness Factors (COMPETE 2020) and by national funds through the Foundation for Science and Technology (FCT) within the scope of project SafEarth-PTDC/ECM-EST/2777/2014 (POCI-01-0145-FEDER-016737). The support from grants SFRH/BD/131006/2017 and SFRH/BPD/97082/2013 is also acknowledged. Acknowledgments are addressed to the Laboratory of Structures (LEST) of the University of Minho, Joao Bernardino, Lda, and TERRACRUA-Construcoes Ecologicas Unipessoal, Lda for building the rammed earth model
Seismic behaviour and strengthening of rammed earth constructions
The widespread use of earthen buildings can be accredited to the local availability of the raw material, sustainability of the building process, and low cost. Earthen structures suffer from high seismic vulnerability, resulting from the low strength of the material, high mass, and lack of engineering approaches in design and building. Despite the extensive use of rammed earth structures, the structural behaviour of such buildings is still not well known, particularly concerning the in-plane and out-of-plane response under cyclic loads. Moreover, proper strengthening solutions are still required to reduce seismic vulnerability. In this context, an experimental program was conducted on the in-plane and out-of-plane cyclic performance of rammed earth structural sub-assemblies. The prototypes, after being damaged, were strengthened by employing a TRM-based solution and subjected to further testing. The experimental results are reported and discussed in terms of cracking pattern and peak base shear coefficient. Finally, the effectiveness of the proposed strengthening solution was evaluated against the performance of the unstrengthened mockups. The outcomes highlighted the effectiveness of the TRM solution in improving the ductility and the in-plane shear capacity of the mockups.This work was partly financed by FEDER funds through the Operational Programme Competitiveness Factors (COMPETE 2020) and by national funds through the Foundation for Science and Technology (FCT) within the scope of project SafEarth—PTDC/ECM-EST/2777/2014 (POCI-01–0145-FEDER-016737). The support from
grants SFRH/BD/131006/2017 and SFRH/BPD/97082/2013 is also acknowledged. Acknowledgments are addressed to the Laboratory of Structures (LEST) of the University of Minho, João Bernardino Lda and TERRACRUA Lda for building the rammed earth model
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