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581.
John W. van de Lindt Hongyan Liu Michael D. Symans Jayesh K. Shinde 《Journal of Earthquake Engineering》2013,17(3):469-490
The concept of base isolation is a century old, but application to civil engineering structures has only occurred over the last several decades. Application to light-frame wood buildings in North America has been virtually non existent with one notable exception. This article quantitatively examines issues associated with application of base isolation in light-frame wood building systems including: (1) constructability issues related to ensuring sufficient in-plane floor diaphragm stiffness to transfer shear from the superstructure to the isolation system; (2) evaluation of experimental seismic performance of a half-scale base-isolated light-frame wood building; and (3) development of a displacement–based seismic design method and numerical model and their comparison with experimental results. The results of the study demonstrate that friction pendulum system (FPS) bearings offer a technically viable passive seismic protection system for light-frame wood buildings in high seismic zones. Specifically, the amount and method of stiffening the floor diaphragm is not unreasonable, given that the inter-story drift and accelerations at the upper level of the tested building were very low, thus resulting in the expectation of virtually no structural, non structural, or contents damage in low-rise wood frame buildings. The nonlinear dynamic model was able to replicate both the isolation layer and superstructure movement with good accuracy. The displacement-based design method was proven to be a viable tool to estimate the inter-story drift of the superstructure. These tools further underscore the potential of applying base isolation systems for application to North America's largest building type. 相似文献
582.
Andrea Prota Fiorenzo de Cicco Edoardo Cosenza 《Journal of Earthquake Engineering》2013,17(4):500-519
This article presents the results of an experimental campaign on the cyclic behavior of smooth steel bars, used as internal reinforcement of existing Reinforced Concrete (RC) structures; the stress-strain relationship is analyzed for different values of L/D ratio, where L is the stirrup spacing and D is the longitudinal bar diameter. Most of the experimental tests concerned smooth bars with L/D ratios ranging between 5 and 100. The analysis of the test results is complemented by some comparisons of the curves obtained by experimental tests on smooth steel bars with those obtained by experimental tests on ribbed steel bars. The theoretical predictions obtained by existing models available in the literature on the cyclic behavior of ribbed steel bars are then discussed. Our review of these formulations underlines their range of applicability as well as their potential to predict the damage and buckling that occur for different L/D ratios of the smooth steel bars. 相似文献
583.
H. H. de Boer M. J. Aarents G. J. R. Maat 《International Journal of Osteoarchaeology》2012,22(4):379-386
The histological staining of bone tissue is of great value in identifying structural changes in human bone tissue when examined microscopically, and is therefore routinely used by clinical pathologists. However, for archaeological and other types of undecalcified dry bone tissue, histochemical staining is currently not widely used. The purpose of this paper is to describe a new method developed for the staining of undecalcified archaeological bone which may be a valuable addition to the palaeopathological toolkit. Sections were ground by hand and stained with haematoxylin and eosin. The microstructure and architecture of the stained sections become clearly visible without compromising total tissue envisioning. In addition, staining enhances differentiation between taphonomically affected and non‐affected bone tissue. This paper accordingly describes a reproducible stepwise method for the production of ground stained sections. An additional troubleshooting paragraph discusses the most often encountered problems and provides solutions. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
584.
Ana Cecilia Rodríguez de Romo 《Journal of the history of the neurosciences》2013,22(3):268-287
This essay analyzes the history of the Nerve Growth Factor (NGF) discovery, relating some of the principles of the theory of scientific creativity to the cognitive and personal qualities of the scientists that participated in the discovery, particulary Rita Levi-Montalcini and Viktor Hamburger. The discovery of NGF is especially attractive for the history of science as it involves chance, luck, creativity, and some extraordinary scientists. 相似文献
585.
A. Trujillo‐Mederos M. Arnay‐de‐la‐Rosa E. Gonzlez‐Reimers A. C. Ordez 《International Journal of Osteoarchaeology》2014,24(5):590-601
Hallux valgus is defined as the lateral deviation of the great toe. It is considered a disease mainly related to the use of boots or shoes that constrict the foot. This process usually ensues along many years and is accompanied by changes at the metatarsophalangeal joint, which serve to make the diagnosis on bare bones. Diagnostic criteria include lateral deviation of the metatarsophalangeal joint (1), lateral subluxation of the first phalanx, degenerative changes of the sesamoid articular facets, and exostosis or remodelling of the medial tuberosity. Following other authors, we have defined hallux valgus as the presence of (1) and any of the other three criteria. In a series of the 18th century burials from the church La Concepción, in Tenerife, Canary Islands, we found 35 cases of hallux valgus out of the 117 cases for which necessary data for the diagnosis could be recorded (29.91%). A significant association was found between changes in the left toe and burial site near the altar, where priests and other people of the high social status were interred. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
586.
Morton E. O'Kelly James F. Campbell Ricardo S. de Camargo Gilberto de Miranda Jr 《Geographical analysis》2015,47(1):73-96
This article formulates a model to analyze the role of fixed costs in the design of optimal transportation hub networks. The primary purpose of this article is to better model costs in hub networks, an issue that has attracted considerable attention. This article allows particular versions of hub networks to emerge from the cost structure, rather than by imposing a rigid predefined connectivity protocol. The article integrates modeling approaches from an environmental hub location model with the three‐index formulation of Ernst and Krishnamoorthy to produce a hub location model with fixed and variable costs for all arcs. Our goal is to demonstrate how the inclusion of a richer cost model in transportation hub location can generate a wide range of different network types, depending on the relative magnitudes of the cost elements. While the existence of special case network solutions is well known and has been exploited in optimization, the current research provides added insight to the cost of flow in a more, or less, connected hub network. Eight fundamental prototype networks are derived as special cases, and some additional unanticipated network types also emerge. The results are illustrated with a standard CAB25 data set. 相似文献
587.
588.
589.
Gian Piero Lignola Vincenzo Giamundo Gianluigi de Martino 《International Journal of Architectural Heritage》2015,9(7):883-895
This study presents the vulnerability analysis of a masterpiece of the architectural heritage of the ancient city of Pompeii in Italy. First, a historical analysis of the structure is proposed; then finite element analyses are discussed to evaluate the seismic vulnerability of the colonnade today, including the effect of water leakage and pollutants in between the marble blocks of the structure. Pompeii, in fact, is a partially buried Roman town-city; after suffering many earthquakes in the past it was destroyed during a long catastrophic eruption of the Vesuvius volcano in 79 ad and remained covered until its accidental rediscovery in 1749. After excavations, the ruins of the ancient town present many partially collapsed buildings, not only due to other earthquakes during the past three centuries, but also due to rapid degradation of the archaeological material. Temples and public places mainly present slender columns and typical shapes of discrete marble overlaying blocks. In the case of the colonnade of the Forum, residing in the main square of the town, an “innovative solution” was adopted for the trabeation. To avoid long span beams over the columns, short segments were built up providing opposing inclined patterned edges. Numerical analyses show the seismic vulnerability of a colonnade, in order to understand how a UNESCO World cultural heritage site can be preserved. The beam segmentation was an “innovative solution” for that period aiming to simplify the constructability of those structures. This solution did not substantially alter the colonnade current seismic vulnerability. Nevertheless any contemporary alteration between blocks could potentially increase the colonnade’s seismic vulnerability, potentially putting at risk cultural heritage and human life. 相似文献
590.
Tiwanaku influence significantly affected the lifestyle of the prehistoric peoples of the Atacama Desert as it represented an important period of social and economic change. Such intense changes as social stratification and new religious and ideological influences have always been characterized as peaceful ones. Palaeopathological studies based on the violence‐induced traumatic lesions of 64 well‐preserved human skeletons from an excavated funerary site named Solcor‐3 have facilitated a comparison between Pre‐Tiwanaku and Tiwanaku periods. Results show an increase in violence between males represented by low‐intensity skull traumas, arrow wounds and a high mortality rate between 20 and 30 years of age during the Tiwanaku period. The interpretation of this data is contrary to the model of peaceful acceptance of the changes that followed the Tiwanaku influence into the Atacama. At least for Solcor‐3, economic and political factors should be re‐considered in order to explain the emergence of social tension during the Tiwanaku period. In the future, more detailed studies will probably help to clarify if conflicts had also extended to other sites in San Pedro de Atacama under Tiwanaku influence. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献