Cyclic testing of reinforced concrete columns with double or one-side headed shear reinforcement

The effectiveness of single-leg crossties that were anchored by heads in reinforced concrete columns was assessed. Seven reinforced concrete columns were tested under reversed cyclic loading with a 10 % axial load of the nominal axial capacity of the columns. Four columns were designed to fail in a flexural mode, and three columns were designed to fail in a shear mode. The main variable was the anchorage type of crossties: conventional crossties that were anchored with 135° and 90° hooks, crossties that were anchored with one-side head and one-side 180° hook, and crossties that were anchored with double heads. The test results indicate that the hysteretic behavior of the columns with crossties that were anchored by double heads or one-side head was similar or superior to the columns with conventional crossties anchored by hooks in terms of ductility and energy dissipation. After the cover concrete spalled, the 90° hooks inevitably opened and the column longitudinal bars buckled. However, the heads could delay the buckling of the column bars and the columns could maintain their capacities until 8 % drift ratio for the columns that were designed to fail in a flexural mode. For the columns that were designed to fail in a shear mode, all columns showed similar behaviors and had identical strengths. The columns with the headed crossties had smaller crack widths than the columns with conventional crossties because the headed crossties well confined the core concrete under severe shear deformation. The test results show that headed crossties can effectively confine the column bars and core concrete of the columns: therefore, the ductility and energy dissipation capacity of the columns were improved

Combined inhibition of Bcl-2 family members and YAP induces synthetic lethality in metastatic gastric cancer with RASA1 and NF2 deficiency

Background Targetable molecular drivers of gastric cancer (GC) metastasis remain largely unidentified, leading to limited targeted therapy options for advanced GC. We aimed to identify molecular drivers for metastasis and devise corresponding therapeutic strategies. Methods We performed an unbiased in vivo genome-wide CRISPR/Cas9 knockout (KO) screening in peritoneal dissemination using genetically engineered GC mouse models. Candidate genes were validated through in vivo transplantation assays using KO cells. We analyzed target expression patterns in GC clinical samples using immunohistochemistry. The functional contributions of target genes were studied through knockdown, KO, and overexpression approaches in tumorsphere and organoid assays. Small chemical inhibitors against Bcl-2 members and YAP were tested in vitro and in vivo. Results We identified Nf2 and Rasa1 as metastasis-suppressing genes through the screening. Clinically, RASA1 mutations along with low NF2 expression define a distinct molecular subtype of metastatic GC exhibiting aggressive traits. NF2 and RASA1 deficiency increased in vivo metastasis and in vitro tumorsphere formation by synergistically amplifying Wnt and YAP signaling in cancer stem cells (CSCs). NF2 deficiency enhanced Bcl-2-mediated Wnt signaling, conferring resistance to YAP inhibition in CSCs. This resistance was counteracted via synthetic lethality achieved by simultaneous inhibition of YAP and Bcl-2. RASA1 deficiency amplified the Wnt pathway via Bcl-xL, contributing to cancer stemness. RASA1 mutation created vulnerability to Bcl-xL inhibition, but the additional NF2 deletion conferred resistance to Bcl-xL inhibition due to YAP activation. The combined inhibition of Bcl-xL and YAP synergistically suppressed cancer stemness and in vivo metastasis in RASA1 and NF2 co-deficiency. Conclusion Our research unveils the intricate interplay between YAP and Bcl-2 family members, which can lead to synthetic lethality, offering a potential strategy to overcome drug resistance. Importantly, our findings support a personalized medicine approach where combined therapy targeting YAP and Bcl-2, tailored to NF2 and RASA1 status, could effectively manage metastatic GC.This research was supported by grants of the National Research Foundation (NRF) funded by the Korean government (NRF-RS-2023–00208984, NRF-2021M3H9A1030260, NRF-2021R1F1A1051220, NRF-2016M3A9D5A01952416)

A Comparative Field Monitoring of Column Shortenings in Tall Buildings Using Wireless and Wired Sensor Network Systems

A comparative field measurement for column shortening of tall buildings is presented in this study, with a focus on the reliability and stability of a wireless sensor network. A wireless sensor network was used for monitoring the column shortenings of a 58-story building under construction. The wireless sensor network, which was composed of sensor and master nodes, employed the ultra-high-frequency band and CDMA communication methods. To evaluate the reliability and stability of the wireless sensor network system, the column shortenings were also measured using a conventional wired monitoring system. Two vibration wire gauges were installed in each of the selected 7 columns and 3 walls. Measurements for selected columns and walls were collected for 270 days after casting of the concrete. The results measured by the wireless sensor network were compared with the results of the conventional method. The strains and column shortenings measured using both methods showed good agreement for all members. It was verified that the column shortenings of tall buildings could be monitored using the wireless sensor network system with its reliability and stability

Collaborative Reliable Event Transport Based on Mobile-Assisted Sensing in Urban Digital Twin

For urban digital twin, this paper comes up with a novel urban data acquisition scheme, denoted by collaborative reliable event transport (cRET), that conducts micro-scale sensing resolution in urban environments. cRET relies on battery-powered sensors with Bluetooth low-energy (BLE) modules and the smart mobile devices that people carry around urban places. However, the traditional data acquisition schemes with mobile assistance suffer from the poor communication channel quality of BLE. So, it is tough to achieve enough reliability of event observation. Hence, cRET utilizes overhearing-based collaboration among sensors to improve the data delivery ratio. It also could support reliable transmission over mobile devices despite high-speed moving. A proof-of-concept demonstrates that the reliability is improved by the overhearing and collaboration among sensors against low-channel conditions and a high moving speed of mobile devices, i.e., 30 km/h and more

Collaborative Reliable Event Transport Based on Mobile-Assisted Sensing in Urban Digital Twin

For urban digital twin, this paper comes up with a novel urban data acquisition scheme, denoted by collaborative reliable event transport (cRET), that conducts micro-scale sensing resolution in urban environments. cRET relies on battery-powered sensors with Bluetooth low-energy (BLE) modules and the smart mobile devices that people carry around urban places. However, the traditional data acquisition schemes with mobile assistance suffer from the poor communication channel quality of BLE. So, it is tough to achieve enough reliability of event observation. Hence, cRET utilizes overhearing-based collaboration among sensors to improve the data delivery ratio. It also could support reliable transmission over mobile devices despite high-speed moving. A proof-of-concept demonstrates that the reliability is improved by the overhearing and collaboration among sensors against low-channel conditions and a high moving speed of mobile devices, i.e., 30 km/h and more

Platinum recycling from fuel cell-spent electrocatalysts using oxidative leaching in HCl solution

The recovery of platinum (Pt) from electrocatalysts in spent proton exchange membrane fuel cells is promising and important for the sustainable development of such a noble metal. Conventional leaching of Pt in the aqueous phase typically requires the use of high concentration of mineral acids and the presence of strong oxidants owing to its thermodynamic stability and non-reactive properties. In the present study, the dissolution of Pt from a Pt/C fuel cell electrocatalyst was investigated using a simple and efficient process under moderate conditions in chloride media. Notably, the leachability of Pt was high ∼76% in a solution of low concentration HCl 2.0 M at 90 °C for 120 min in the absence of an oxidant. The enhancement of Pt leaching efficiency can be obtained using various oxidizing agents HNO3, H2O2, NaClO and NaClO3, and NaClO3 shown the most effective improvement from 76% to 88%. The dissolution of Pt in a solution of 2.0 M HCl and 3.0 wt% NaClO3 improved to 98% by the increase in leaching temperature from 50 to 90 °C. Kinetic studies indicated that Pt leaching in HCl in the presence of NaClO3 followed a chemical-controlled mechanism with an activation energy (Ea) of 40.6 kJ/mol. Based on the findings of this study, an efficient process is proposed to recover and reuse Pt from an electrocatalyst sample of spent fuel cells, including oxidative leaching, chemical precipitation and laser reduction

Impact of Grid Density on the les Analysis of Flow CCV: Application to the TCC-III Engine under Motored Conditions

Large-eddy simulation (LES) applications for internal combustion engine (ICE) flows are constantly growing due to the increase of computing resources and the availability of suitable CFD codes, methods and practices. The LES superior capability for modeling spatial and temporal evolution of turbulent flow structures with reference to RANS makes it a promising tool for describing, and possibly motivating, ICE cycle-to-cycle variability (CCV) and cycle-resolved events such as knock and misfire. Despite the growing interest towards LES in the academic community, applications to ICE flows are still limited. One of the reasons for such discrepancy is the uncertainty in the estimation of the LES computational cost. This in turn is mainly dependent on grid density, the CFD domain extent, the time step size and the overall number of cycles to be run. Grid density is directly linked to the possibility of reducing modeling assumptions for sub-grid scales. The extent of the computational domain influences the impact of the boundary conditions on the CFD results. The time-step size needs to be set according to the size of the resolved turbulent eddies. It is therefore closely tied to local grid size with the constraint that the CFL number should be lower than unity everywhere in the domain for the highest accuracy. The overall number of simulated cycles influences the soundness of the statistical analysis of LES outcomes. This paper focuses on the impact of grid density on the LES description of the TCC-III single-cylinder optical engine flow under motored conditions. In particular, attention is focused on the intake stroke of the engine cycle, which governs the induced flow motion. LES results are first evaluated by means of well-established quality indices to find the insufficient grid resolution region to be refined. Second, comparisons with available PIV measurements are carried out. Finally, COV and proper orthogonal decomposition analyses are adopted to further assess the impact of grid density on CCV

A Case Study on the Rehabilitation of a Fire-Damaged Structure

This paper presents a case study on the rehabilitation of a fire-damaged structure and describes the results of a site investigation and tests, leading to a plan for the rehabilitation of the structure. The fire took place in the main control room of a thermal power plant and lasted about three hours until it was finally extinguished. To set up a rehabilitation plan for the damaged structure, a visual inspection of the damaged condition was first carried out, which was followed by analysis and on-site material tests indicating the degree of neutralization progress in the remaining structure. Specimens of damaged concrete and reinforcing bars were sampled and tested for their residual strengths. As a conclusion, two methods of rehabilitation were suggested considering the current condition of the structure and the sequence of construction

Agent-Based Multipath Management for Supporting Sink Mobility in Wireless Sensor Networks

In wireless sensor networks, sink mobility support is one of the essential functionalities in many applications. With continuous advancement, future applications will require not only sink mobility support but also high-performance data delivery service. Multipath routing is one of the promising technologies for improving data delivery performance by collaboratively using alternative or redundant multiple routing paths. However, existing multipath routing protocols had not dealt with sink mobility. As a result, they lead to bad performance in terms of energy efficiency due to the end-to-end path reconstruction. Consequently, a novel multipath management scheme is required thereby supporting sink mobility without performance degradation. In this paper, we propose a multipath management scheme for supporting sink mobility. The proposed scheme dynamically constructs multipath along the moving path of a sink. In addition, the proposed scheme provides the path shortening schemes according to the sink’s movement for reducing energy consumption. Our simulation results show that the proposed scheme is superior to existing path management schemes in terms of reliability and energy efficiency