Aplastic anemia (AA) is a type of anemia that is caused by an intrinsic defect of hematopoietic progenitors or an extrinsic immune mediated destruction of stem cells. Patients commonly presented with pancytopenia, particularly leukopenia that renders patient susceptible to various infections. COVID-19 is one of these infections that could be life threatening and highly contagious. Infection with COVID-19 is expected in a patient who developed fever, respiratory manifestations, leukopenia and lymphopenia together with history suggestive of exposure to infection. Furthermore COVID-19 was found associated with thrombocytopenia, agranulocytosis and monocytopenia in severe cases. Thus the relationship between COVID-19 infection and AA would be a vicious circle as both cause leukopenia and lymphopenia. This study aimed to break this circle, through proposing risk stratification of vulnerability to COVID-19 in

Pushover analysis has been recommended as a reliable tool to estimate the seismic capacity of the structures. Vertical irregular structures are highly vulnerable during earthquakes due to stiffness irregularity in their elevations. Hence, seismic capacities of these types of structures need to be re-estimated during structural design stage. So, in this paper, an attempt has been made to assess the actual seismic performance of buildings with two common types of vertical irregularities such as; soft story and setback in comparison with regular (reference) building. These types of vertical irregularities are studied in individual cases, combined in one story, and combined in two different stories of the building models, while most previous studies satisfy with individual type of vertical irregularity case in the studied model. In addition, combined vertical irregularity generates extra weak points, which alter the seismic capacities, failure mode mechanism, and performance point location.
Three-dimensional numerical models are created to find out significant response demand such as; the variation in periods of vibration, lateral displacement, inter-story drift, pushover curve, and plastic hinges formation. The results showed that vertical irregular buildings are subjected to early damages and have less seismic capacity than regular one. The fundamental time period becomes misleading term in seismic force calculation for vertical geometric irregular buildings and needs to be re-considered. In addition, extra lateral displacement and inter-story drift are passively generated in the vertical irregular buildings due to sudden change in stiffness. Significant negative variation in the pushover curves, ductility ratios, and plastic hinges’ formation is observed when combinations of pre-mentioned vertical irregularity cases occur. Buildings with open soft ground story with asymmetric setback should have additional precautions from international codes during structural design
stage according to their irregularity ratio. Therefore, response modification/reduction factor (R) may be scaled-down to adapt these negative variation in seismic capacities.

In existing research, the correlation between the resilience performance of the self-centering post-tensioned (SCPT) steel beam-column connections and the inelastic response of the required energy dissipation (ED) system was not addressed. For this purpose, a compact circular hollow steel tube (CHST) is proposed as a replaceable ED system. In the light of existing experimental results, a detailed three-dimensional finite element modeling (3D-FEM) was carried out to identify the response of the compact CHST under half cyclic loading. A lot of numerical work is concluded with the extraction of design charts to determine the axial strain (ΔL/L) of the ED system prior to encountering post-yield buckling. Therefore, in the numerically validated reference SCPT connection, several ED systems predesigned according to the design charts emphasized the capability of design charts to predict and control the resilient response of the connections. The optimum selection of proper inherent depth to thickness (D/t) ratio and length to depth (L/D) ratio of the CHST-ED system can increase the resilience of modern self-centering steel structures.

Soil flexibility had an obvious effect on damage of buildings during past seismic events. When a structure is subjected to earthquake, its foundation undergoes three modes of deformation, namely vertical, sliding, and rocking. Indeed, the present practice of structural design assumes that buildings are fixed at their base as a simulation of the connection between columns and foundation. However, in reality, the supporting soil flexibility especially, under the raft foundation system permits extra lateral deformation to their natural deformation. So, implementing soil-structure interaction (SSI) modeling enables the designer to assess the actual inelastic seismic performance and base shear capacity of the structural system during seismic event. In this study, three-dimensional finite element (FE) models of multi-story moderate-rise buildings of moment resisting frame (MRF) are idealized using ETABS to analyze the effects of soil flexibility underneath raft foundation on the performance based seismic design (PBSD). Winkler model spring is used for soil-structure interaction’s simulation in both vertical and horizontal directions. Comparison is carried out between different methods of soil subgrade modulus’s calculation such as FEMA, NIST, and ECP-202. Also, the results obtained for models with various soil types, and raft thickness are compared to those corresponding to fixed-base support. The findings demonstrate that numerical models using flexible (soft) soil, using ECP-202 equations, or less raft thickness have extra time period, lateral deformation, and inter-story drift (ISD) than that with fixed base or even with stiff soil. Also, the capacity curve, global ductility ratio, overstrength ratio, and damage index have evident variation of inelastic seismic performance as a result of SSI. 

Structural damage identification has recently become one of the most important topics for engineering structures due to its benefits in enhancing safety, reducing life-cycle cost and providing guidance for system construction and maintenance. This research investigates the accuracy of using displacement influence lines (DILs) and their derivatives (slope and curvature) for structural damage characteristics (location and severity). The method is based on static structure response, which can be measured using single or multi sensors. The study includes an analytical investigation of damage detection of single and multiple damages in a simply supported beam. The measuring point positions are also discussed in this paper. Furthermore, the advantages and disadvantages of using displacement influence lines in structural damage detection are also discussed.

Concrete-filled steel tube (CFST) beam-column joints are susceptible to brittle premature failure due to concentrated local stresses at the tips of the beam tension flange. In order to reduce the outward deformation of the steel tube wall, this paper addresses the influence of setting the steel beam at the corner of the CFST column on the connection performance. Therefore, two specimens represented the details of the common connection and the new proposed connection of exterior joint configuration were sub-assembled and examined experimentally under lateral monotonic loading. Compared with the flexible initial stiffness attained by the common connection, the results showed that the initial stiffness of the proposed connection was relatively rigid up to yielding of the middle region of the width of the beam compression flange under high bearing stresses. The connection strength also increased up to the expected design strength of the connecting beam, while the common connection strength was close to half of the beam design strength. Moreover, after the strength of the beam connection was achieved and at a total rotation of 0.025rad, the failure of the proposed connection was a significant buckling of the beam compression flange propagated to its web and associated with section warping.

Disposal of mining wastes (tailings) is one of the most severe issues related to groundwater contamination. Therefore, a properly selected disposal site helps to prevent the leakage of dissolved materials in the tailings to groundwater, especially in the karstic area. Where the karstic environment is one of the challenges facing groundwater environmental and engineering issues, for instance, groundwater exploration, vulnerability assessment, and hazard estimation. In this study, the resistivity method with a high-resolution surface data survey was carried out to investigate the pond location selection for mining tailings disposal at El Mochito mine site, northwest Honduras. The results of the two-dimensional (2-D) inversion for sixteen surveyed lines revealed that many low resistivity zones. These zones are related to water/clay-bearing zones that are structurally weak. From lines 8-12, the limestone underneath the surface is the most compact, and this is the best location in the survey area for tailings pond construction. The resistivity method has provided insight into the subsurface information and locating hydraulically conductive zones, so it can be useful for selecting the site of mining tailings.