scholarly journals Fragility assessment of existing low-rise steel moment-resisting frames with masonry infills under mainshock-aftershock earthquake sequences

2021 ◽  
Vol 19 (6) ◽  
pp. 2483-2504
Author(s):  
Luigi Di Sarno ◽  
Jing-Ren Wu
Keyword(s):  
Seismic Vulnerability ◽  
Steel Frames ◽  
Steel Frame ◽  
Second Phase ◽  
Moment Frames ◽  
Damage Level ◽  
Masonry Infills ◽  
Aftershock Sequences ◽  
The Impact ◽  
Multiple Earthquakes

AbstractThis paper presents the fragility assessment of non-seismically designed steel moment frames with masonry infills. The assessment considered the effects of multiple earthquakes on the damage accumulation of steel frames, which is an essential part of modern performance-based earthquake engineering. Effects of aftershocks are particularly important when examining damaged buildings and making post-quake decisions, such as tagging and retrofit strategy. The procedure proposed in the present work includes two phase assessment, which is based on incremental dynamic analyses of two refined numerical models of the case-study steel frame, i.e. with and without masonry infills, and utilises mainshock-aftershock sequences of natural earthquake records. The first phase focuses on the undamaged structure subjected to single and multiple earthquakes; the effects of masonry infills on the seismic vulnerability of the steel frame were also considered. In the second phase, aftershock fragility curves were derived to investigate the seismic vulnerability of infilled steel frames with post-mainshock damage caused by mainshocks. Comparative analyses were conducted among the mainshock-damaged structures considering three post-mainshock damage levels, including no damage. The impact of aftershocks was then discussed for each mainshock-damage level in terms of the breakpoint that marks the onset of exceeding post-mainshock damage level, as well as the probability of exceeding of superior damage level due to more significant aftershocks. The evaluation of the efficiency of commonly used intensity measures of aftershocks was also carried out as part of the second phase of assessment.

scholarly journals DYNAMIC RESPONSE OF EXISTING STEEL FRAMES WITH MASONRY INFILLS UNDER MULTIPLE EARTHQUAKES

2020 ◽  
Author(s):  
Luigi Di Sarno ◽  
Jing-Ren Wu ◽  
Fernando Gutiérrez-Urzúa ◽  
Fabio Freddi ◽  
Mario D’Aniello ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Steel Frames ◽  
Masonry Infills ◽  
Multiple Earthquakes

scholarly journals Does Multidisciplinary Team Simulation-Based Training Improve Obstetric Emergencies Skills?

Healthcare ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 170
Author(s):  
Encarna Hernández ◽  
Marcos Camacho ◽  
César Leal-Costa ◽  
María Ruzafa-Martínez ◽  
Antonio Jesús Ramos-Morcillo ◽  
...  
Keyword(s):  
Health Professionals ◽  
Multidisciplinary Team ◽  
Simulation Training ◽  
Observer Agreement ◽  
Second Phase ◽  
High Fidelity ◽  
Breech Delivery ◽  
Obstetric Emergencies ◽  
Quasi Experimental ◽  
The Impact

Clinical simulation in obstetrics has turned out to be a tool that can reduce the rate of perinatal morbidity and mortality. The objective of this study was to analyze the impact and evaluate the effects of training with high-fidelity simulation of obstetric emergencies on a multidisciplinary group. The quasi-experimental research study was structured in three phases: a first phase where the most important obstetric emergencies were determined, a second phase of design and development of the selected cases for simulation training, and a third and final phase where the abilities and satisfaction of the multidisciplinary team were analyzed. Three scenarios and their respective evaluation tools of obstetric emergencies were selected for simulation training: postpartum hemorrhage, shoulder dystocia, and breech delivery. The health professionals significantly improved their skills after training, and were highly satisfied with the simulation experience (p < 0.05). An inter-observer agreement between good and excellent reliability was obtained. Regarding conclusions, we can state that high-fidelity obstetric emergency simulation training improved the competencies of the health professionals.

scholarly journals Effect of Short-Term Carbapenem Restriction on Antimicrobial Susceptibility of Resistant Gram-Negative Bacilli in an ICU

2020 ◽  
Vol 41 (S1) ◽  
pp. s200-s201
Author(s):  
Mariana Melo ◽  
Raquel Bandeira ◽  
lio de Castro Giselle Dias ◽  
Braulio Couto
Keyword(s):  
High Mortality ◽  
Bacterial Resistance ◽  
Statistical Significance ◽  
Public Health Problem ◽  
Resistance Rate ◽  
Second Phase ◽  
Short Term ◽  
Intervention Phase ◽  
Carbapenem Resistant ◽  
The Impact

Background: Carbapenem-resistant GNB infections are a serious public health problem worldwide, particularly due to the high mortality associated with them and the low number of therapeutic options. One approach to this challenge is the development of antimicrobial stewardship programs. Objective: We evaluated the impact of a carbapenem restriction program on reducing of bacterial resistance in an intensive care unit (ICU). Methods: A retrospective study conducted in 2 phases in the 80-bed ICU of an acute-care public hospital in Minas Gerais, Brazil. The preintervention phase lasted 16 months (January 2018–April 2019) and the second phase (carbapenem restriction), after the intervention, lasted 4 months (May–August 2019). The intervention was defined as carbapenem-sparing and the use of meropenem was authorized in 3 situations: (1) treatment of serious infections documented by extended-spectrum β-lactamase–producing Enterobacteriacea (ESBL); (2) therapeutic failure with the use of another antimicrobial; and (3) infectious disease recommendation. Data were obtained through consultation of electronic medical records and microbiological results, as standardized by the CLSI, for patients with a >48-hour stay in the ICU and who met the criteria for healthcare-associated infection (HAI) according to the CDC NHSN definition. Results: Before the intervention, on average, 50 cultures were obtained with positive results for multidrug-resistant GNB–MER-GNB (SD, 12.2) and in the intervention phase, this number was 31 cultures (SD, 12.8; P = .010). Average carbapenem consumption decreased significantly with corresponding increase in cefepime consumption in the same period (Fig. 1). The ATB (DDD per 1,000 patient days) before the intervention for carbapenems was 110.6 (SD, 97.1) and for cefepime was 8.2 (SD, 5.9). In the intervention phase, the ATB for carbapenems was 44.7 (SD, 38.5; P = .015) and for cefepime it was 32.0 (SD, 20.3; P < .001). In terms of multidrug resistance rate, before the intervention, 95 of 149 of Acinetobacter (64%) were resistant and during the intervention, 13 of 30 Acinetobacter (43%) were resistant (P = .043). Other GNB (Klebsiella, Proteus, Escherichia coli, and Pseudomonas) reduced the resistance rate, but without statistical significance. We observed a reduction in the HAI rate per MDR-GNB (Fig. 2): before the intervention, it was 22.7 (SD, 5.5) and during the intervention phase it was 16.5 (SD, 7.7; P = .07), although this change did not reach statistical significance. Nevertheless, the ICU Klebsiella infection rate did significantly decrease; it was 5.5 (SD, 1.9) before the intervention and 2.4 (SD, 1.8) after the intervention (P = .009). Conclusions: Short-term carbapenem restriction may be an effective strategy to reduce the incidence of carbapenem-resistant GNB infections in the ICU. The scarce arsenal available for the treatment of MDR-GNB and the high mortality rate justify the growing need for stewardship programs in Brazilian ICUs.Funding: NoneDisclosures: None

Experimental Research and Finite Element Analysis on Behavior of Steel Frame with Semi-Rigid Connections

2010 ◽  
Vol 168-170 ◽  
pp. 553-558
Author(s):  
Feng Xia Li ◽  
Bu Xin
Keyword(s):  
Architectural Design ◽  
Plastic Hinge ◽  
Steel Frames ◽  
Seismic Energy ◽  
Internal Force ◽  
Steel Frame ◽  
Frame Structure ◽  
Element Analysis ◽  
Rigid Deformation ◽  
Steel Frame Structure

Most steel beam-column connections actually show semi-rigid deformation behavior that can contribute substantially to overall displacements of the structure and to the distribution of member forces. Steel frame structure with semi-rigid connections are becoming more and more popular due to their many advantages such as the better satisfaction with the flexible architectural design, low inclusive cost and environmental protect as well. So it is very necessary that studying the behavior of those steel frame under cyclic reversal loading. On the basics of connections experiments the experiment research on the lateral resistance system of steel frame structure has been completed. Two one-second scale, one-bay, two-story steel frames with semi-rigid connections under cyclic reversal loading. The seismic behavior of the steel frames with semi-rigid connections, including the failure pattern, occurrence order of plastic hinge, hysteretic property and energy dissipation, etc, was investigated in this paper. Some conclusions were obtained that by employing top-mounted and two web angles connections, the higher distortion occurred in the frames, and the internal force distributing of beams and columns was changed, and the ductility and the absorbs seismic energy capability of steel frames can be improved effectively.

scholarly journals Integrative analysis of <i>Geobacter</i> spp. and sulfate-reducing bacteria during uranium bioremediation

2012 ◽  
Vol 9 (3) ◽  
pp. 1033-1040 ◽  
Author(s):  
M. Barlett ◽  
K. Zhuang ◽  
R. Mahadevan ◽  
D. Lovley
Keyword(s):  
Sulfate Reducing Bacteria ◽  
Field Trials ◽  
Second Phase ◽  
Sulfate Reducing ◽  
Organic Electron ◽  
Poor Understanding ◽  
Key Factor ◽  
Reducing Bacteria ◽  
The Impact

Abstract. Enhancing microbial U(VI) reduction with the addition of organic electron donors is a promising strategy for immobilizing uranium in contaminated groundwaters, but has yet to be optimized because of a poor understanding of the factors controlling the growth of various microbial communities during bioremediation. In previous field trials in which acetate was added to the subsurface, there were two distinct phases: an initial phase in which acetate-oxidizing, U(VI)-reducing Geobacter predominated and U(VI) was effectively reduced and a second phase in which acetate-oxidizing sulfate reducing bacteria (SRB) predominated and U(VI) reduction was poor. The interaction of Geobacter and SRB was investigated both in sediment incubations that mimicked in situ bioremediation and with in silico metabolic modeling. In sediment incubations, Geobacter grew quickly but then declined in numbers as the microbially reducible Fe(III) was depleted whereas the SRB grow more slowly and reached dominance after 30–40 days. Modeling predicted a similar outcome. Additional modeling in which the relative initial percentages of the Geobacter and SRB were varied indicated that there was little to no competitive interaction between Geobacter and SRB when acetate was abundant. Further simulations suggested that the addition of Fe(III) would revive the Geobacter, but have little to no effect on the SRB. This result was confirmed experimentally. The results demonstrate that it is possible to predict the impact of amendments on important components of the subsurface microbial community during groundwater bioremediation. The finding that Fe(III) availability, rather than competition with SRB, is the key factor limiting the activity of Geobacter during in situ uranium bioremediation will aid in the design of improved uranium bioremediation strategies.

The Impact of Composition and Sintering Temperature for Stainless Steel Foams (SS316L) Fabricated by Space Holder Method with Urea as Space Holder

2017 ◽  
Vol 888 ◽  
pp. 413-417 ◽  
Author(s):  
Zulaikha Abdullah ◽  
Sufizar Ahmad ◽  
Musfirah Ramli
Keyword(s):  
Stainless Steel ◽  
Biomedical Application ◽  
Metal Foams ◽  
Morphological Properties ◽  
Solid Matrix ◽  
Morphological Observation ◽  
Second Phase ◽  
Space Holder ◽  
Closed Cell ◽  
The Impact

Metal foams are a cellular structure that has a solid matrix made of metal and has pores in their structure. Metal foams offer excellent combination of properties which led researchers interested in investigation in recent years. Closed-cell stainless steel (SS316L) foams for biomedical application were prepared by space holder method and the physical and morphological properties of SS316L foams were studied. Stainless steel (SS316L) powders as metallic material, polyethylene glycol (PEG) as a binder and Urea as a space holder material were mixed homogenously to avoid the particle wrecked. This mixture was compacted using uniaxial pressing machine and pressurized to 8 tons to formed the green body. By using tube furnace, the SS316L foams was two-stage sintered, the first phase at 600°C for 2 hours to decompose the urea, and the second phase at 1000°C, 1100°C, and 1200°C respectively to sinter the steel. The porosity and density test was carried out by applying Archimedean principles, while morphological observation was done by using Field Emission Scanning Electron (FESEM). The samples with 40wt.% SS316L composition and sintered at temperature of 1100°C, leads to porosities of about 44.539% and show the potential as the best metal foams.

Seismic Vulnerability of Existing RC Buildings and Influence of the Decoupling of the Effective Masonry Panels from the Structural Frames

2012 ◽  
Vol 268-270 ◽  
pp. 646-655
Author(s):  
Fabio de Angelis ◽  
Donato Cancellara
Keyword(s):  
Reinforced Concrete ◽  
Seismic Vulnerability ◽  
Seismic Analysis ◽  
Effective Interaction ◽  
Collapse Mechanism ◽  
Limit States ◽  
Capacity Curves ◽  
Masonry Infills ◽  
N2 Method ◽  
Structural Frame

In the present work we discuss on the seismic vulnerability of reinforced concrete existing buildings. In particular we consider a reinforced concrete building originally designed for only gravitational loads and located in a zone recently defined at seismic risk. According to the Italian seismic code NTC 2008 a displacement based approach is adopted and the N2-method is considered for the nonlinear seismic analysis. In the analysis all the masonry infill panels in effective interaction with the structural frame are considered for the nonlinear modeling of the structure. The influence of the effective masonry infills on the seismic response of the structure is analyzed and it is discussed how the effect of the masonry infills irregularly located within the building can give rise to a worsening of the seismic performance of the structure. It is shown that in the present case a not uniform positioning of the masonry infills within the building can give rise to a fragile structural behavior in the collapse mechanism. Furthermore a comparative analysis is performed by considering both the structure with the effective masonry infills and the bare structural frame. For these two structures a pushover analysis is performed, the relative capacity curves are derived and it is shown that fragile collapse mechanisms can occur depending on the irregular positioning of the effective masonry infills. Accordingly it is discussed how in the present case a decoupling of the effective masonry infills from the structural frame can give rise to a smoother response of the capacity curves. For the examined case of an obsolete building with irregular positioning of the masonry panels, the choice of decoupling the effective masonry panels from the structural frame may facilitate the retrofitting strategies for the achievement of the proper safety factors at the examined limit states.

scholarly journals Diferencias cinemáticas del golpeo de fútbol entre futbolistas expertos y sujetos inexpertos (Soccer kick kinematic differences between experienced and non-experienced soccer players)

Retos ◽  
2015 ◽  
pp. 63-66
Author(s):  
Alejandro Muñoz López ◽  
José Antonio González Jurado
Keyword(s):  
Knee Flexion ◽  
Maximum Power ◽  
Soccer Players ◽  
Second Phase ◽  
Film System ◽  
Phase Duration ◽  
Soccer Kick ◽  
The Impact ◽  
Hip Extension

Objetivo: Examinar las diferencias cinemáticas del golpeo con empeine entre futbolistas expertos y sujetos inexpertos. Sujetos: Se analizaron 17 hombres de 17 a 21 años. Metodología: Se utilizó un sistema de fotogrametría 3D con cuatro cámaras. Los sujetos ejecutaron golpeos con el empeine a máxima potencia. Se analizó la Velocidad del Pie en el Impacto, la Máxima Extensión de Cadera, la Máxima Flexión de Rodilla y la Duración de las Fases del gesto. Resultados: Se hallaron diferencias significativas en la Velocidad del Pie de la pierna no hábil en el momento del impacto (m/s) (Expertos: 14,5±.52, Inexpertos: 12.5±.5; p<.001) y Máxima Extensión de Cadera (grados) (Expertos: 39.2±1.3, Inexpertos: 34.28±3.2; p<.001). También hubo diferencias significativas en la Duración de la Fase 2 en ambas piernas (p<.05). Conclusiones: El golpeo con el empeine total en fútbol presenta diferencias significativas entre grupos de diferente nivel tan solo en la pierna no dominante. Palabra clave: golpeo, fútbol, biomecánica, empeine.Abstract: T; Purpose: to examine kinematic differences of instep soccer kick between experienced and non-experienced soccer players. Subjects: 17 men between 17 and 21 years old. Methodology: a 3D film system with 4 cameras was used. Maximum power instep kicks were executed. It was analyzed feet velocity in the impact, maximum hip extension, maximum knee flexion and kick phases duration. Results: were found significant differences in feet velocity with non-dominant leg in the impact moment (m/s) (Experienced: 14.5±.52, Non-experienced: 12.5±.5; p<.001) and maximum hip extension (degrees) (Experienced: 39.2 ± 1.3, Non-experienced: 34.28±3.2; p<.001). Also were significant differences in the second phase duration in both legs (p<.05). Conclusions: Maximum instep soccer kick show significant differences between groups of different level only in non-dominant leg.Key words: kick, soccer, biomechanics, instep.

scholarly journals A Comparison between Dedicated and Flexible Manufacturing Systems: Optimization and Sensitivity Analysis

2021 ◽  
Vol 40 (1) ◽  
pp. 130-139
Author(s):  
Abdul Salam Khan ◽  
Khawer Naeem ◽  
Raza Ullah Khan
Keyword(s):  
Sensitivity Analysis ◽  
Flexible Manufacturing ◽  
Manufacturing Systems ◽  
Manufacturing System ◽  
Cost Minimization ◽  
Process Time ◽  
Future Research ◽  
Second Phase ◽  
Solution Approach ◽  
The Impact

An abrupt change requires a robust and flexible response from a manufacturing system. Dedicated Manufacturing System (DMS) has been a long practiced taxonomy for mass production and minimum varieties. In contrast, Flexible Manufacturing System (FMS) has been introduced for responding to quantity as well as variety issues. This study considers both production taxonomics by using a multi objective model of cost and time. An Integer Linear Programming (ILP) formulation is presented and subsequently validated. The analysis procedure is administered in two phases. In the first phase, comparison of production cost and process time in DMS and FMS is presented. The model is implemented by using an exact solution approach and results show that FMS is a viable option, compared to DMS, according to the criteria of cost, time, and productivity. In the second phase, sensitivity analysis is performed by using several FMS (n) and the impact of cells selection on the performance of system is studied. It is concluded that n=1 (single cell-based FMS) is more relevant for cost minimization; however, n = 6 is a suitable candidate for producing more quantity in given time horizon (process time minimization). Lastly, key findings are reported, and future research avenues are provided.

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