Inerter-Connected Double Tuned Mass Damper for Passive Control of Buildings under Seismic Excitation

In current work the Inerter-Connected Double Tuned Mass Damper (ICDTMD) is employed for structural control of a well-recognized benchmark 10-story linear shear building. The ICDTMD is introduced to overcome the practical limitations of the roof-top tuned mass damper inerter (TMDI), in which the second terminal of the inerter is connected to the lower floors of the building. To this end, a modification of the double tuned mass damper (DTMD) with a linking inerter is proposed to not only exploit the promising features of inerter but also surmount the architectural interference of the effective TMDI configurations. The TMDs free parameters are optimized using particle swarm optimization algorithm (PSO) for two different single objective functions, i.e., the H∞ norms of roof displacement and story drifts were minimized for robust tuning. To evaluate the robustness of the optimal damper, its performance was compared to a traditional roof-top single tuned mass damper (STMD) and DTMD in both frequency and time domains (time history analysis for four far- and near-field records) for different preselected mass and inertance ratios. The performance indices in the time domain were selected as the maximum story drifts, story acceleration and shear. Results show that the rooftop ICDTMD, unlike the rooftop TMDI, provides a similar level of response reduction as STMD, while being more reliable due to redundancy. In addition, the ICDTMD exhibits a similar level of response reduction as the DTMD with significantly smaller optimized spring stiffness

Protective effect of vitamin C against hemolytic anemia-induced changes in small intestine histoarchitecture of phenylhydrazine-treated mice

Background and aims: Hemolytic anemia-induced hypoxia can lead to multi-organ dysfunctions. The aim of the present study was to explore the efficacy of vitamin C as an antioxidant agent against hemolytic anemia-induced changes in small intestine histoarchitecture of phenylhydrazine (PHZ)-treated mice. Methods: In this experimental study, adult male mice were randomly assigned to four groups of eight mice each. PHZ was administered to two groups of mice at a dose of 60 mg/kg per 48 hours intraperitoneally for 35 days. One of these groups received vitamin C (250 mg/kg per day) intraperitoneally four hours before PHZ administration. A vehicle-treated control group and a vitamin C control group were also included. 24 hours after the last treatment, desired segments of small intestines were dissected out and subjected to histological processing and morphometric parameters were evaluated. Results: PHZ caused significant decreases in villi width of duodenum and jejunum, crypts depth of duodenum, distribution rate of the goblet cells in ileal villi and height of villi in all segments of small intestine. Vitamin C markedly improved all changes in the aforementioned parameters. Conclusion: Vitamin C could ameliorate hemolytic anemia-induced histological injuries in mouse small intestine

Residual Life and Reliability Assessment of Underground RC sanitary Sewer Pipelines Under Uncertainty

Prioritization of limited funding for pipelines maintenance is a major issue that concerns municipalities nationwide. Conducting a probabilistic assessment can provide a complete characterization of the performance of structural elements and systems along with optimizing the limited resources. The most widely used probabilistic performance indicator is reliability, a measure of the probability of failure corresponding to a particular limit state (e.g., ultimate strength or serviceability). Reliability methods can be used to identify which pipeline sections within a particular system require the most urgent inspection or repair. To this end, an automated data-driven framework for large diameter reinforced concrete pipes (RCPs) is developed that converts the raw unfiltered inspection readings to data that is used for estimating residual life and further reliability assessment purposes. In the current work, initially, the wall thickness erosion is determined based on the inspection data collected using Light Detection and Ranging (LiDAR). Furthermore, the best fit among several probability distribution functions for the wall thickness loss is obtained, which is integrated with a serviceability limit state that defines failure as the complete loss of 1-in concrete cover caused by environmental conditions such as sulfide-induced erosion. Considering this limit state and a prescribed probability of exceedance threshold, a reliability-based prediction of the remaining service life is proposed. The developed framework requires minimal user interference and is, therefore, less time consuming and more consistent compared to previous research. From an asset management point of view, the most vulnerable pipeline sections are identified that will require further inspection and attention. This will provide decision makers crucial information regarding the current state of the pipeline network, to better allocate the already scarce maintenance funding of these pipelines

Wind-Induced Response of Inclined and Yawed Ice-Accreted Stay Cable Models

During the past decades, wind-induced vibrations of bridge stay cables were reported to occur under various incipient conditions. The ice formation on stay cables is one of these conditions, which causes the ice-accreted stay cables to alter their cross section geometry, thus modifying their aerodynamic characteristics. Wind tunnel tests and several CFD simulations were performed for ice-accreted inclined bridge stay cables with two ice-accretion profiles dimensions, 0.5D and 1D, where D is the diameter of the cable. Wind-induced vibrations were analyzed experimentally for cable models with yaw inclination angles of 0°, 30°, and 60° and vertical inclination angles of 0° and 15°, for Reynolds numbers of up to 4 × 105. The aerodynamic drag and lift coefficients of the cable models and the pressure coefficients were determined from the CFD-LES simulations. The experimental results indicated that the vertical and torsional vibrations of the ice-accreted stay cables increased with the increase of the vertical and yaw angles. Also, higher vertical and torsional vibration amplitudes were measured for the case with larger ice thickness, indicating the effect of the ice accretion profile on the cable wind-induced response

Protective Effect of Royal Jelly against Phenylhydrazine-induced Histological Injuries of Small Intestine of Mice: Morphometric Analyses

Background and Objectives: Phenylhydrazine (PHZ), as a known hemolytic agent, causes toxicity in different tissues at various levels. The aim of the current study was to examine the possible protective effects of royal jelly (RJ) against PHZ-induced histological injuries of small intestine in mice. &nbsp; Methods: In this experimental study, adult male mice were randomly divided into four groups of 8 mice each. PHZ was administered intraperitoneally to two groups of mice (at a dose of 60mg/kg) every 48 hours for 35 days. One of the groups received RJ (100mg/kg) orally 4 hours before PHZ administration. The third group only received RJ, and the forth group was considered as control. Twenty-four hours after the last treatment, different segments of small intestine were dissected out, then histological sections were prepared and quantitative morphometric assessments were performed. To compare the groups, one-way ANOVA and multiple comparative Tukey tests were used. The significance level was considered to be p<0.05. &nbsp; Results: In this study, PHZ caused significant decreases in depth of duodenal crypts, distribution rate of the goblet cells in ileal villi, width of duodenal and jejunal villi, and height of villi in all three segments of small intestine. Co-administration of RJ partially improved the changes in the above parameters. &nbsp; Conclusion: From results of this study, it seems that RJ as a free radical scavenger could reduce PHZ-induced intestinal toxicity in mouse