Cyclic response of reinforced concrete composites columns strengthened in the plastic hinge region by HPFRC mortar

The brittleness of concrete raises several concerns due to the lack of strength and ductility in the plastic hinge region of reinforced concrete columns. In this study, in order to improve the seismic strength and performance of reinforced concrete columns, a new method of seismic strengthened reinforced concrete composite columns was attempted by applying High Performance Fiber Reinforced Cementitious composites (HPFRCs) instead of concrete locally in the plastic hinge region of the column. HPFRC has high-ductile tensile strains about 2–5% with sustaining the tensile stress after cracking and develops multiple micro-cracking behaviors. A series of column tests under cyclic lateral load combined with a constant axial load was carried out. Three specimens of reinforced concrete composite cantilever columns by applying the HPFRC instead of concrete locally in the column plastic hinge zone and one of a conventional reinforced concrete column were designed and manufactured. From the experiments, it was known that the developed HPFRC applied reinforced concrete columns not only improved cyclic lateral load and deformation capacities but also minimized bending and shear cracks in the flexural critical region of the reinforced concrete column

Seismic Improvement of RC Beam-Column Joints Using Hexagonal CFRP Bars combined with CFRP Sheets

Under severe earthquake conditions, the lack of strength and ductility in reinforced concrete beam–column joints with non-seismic details raises serious concerns for overall structural safety. In this study, experimental research was carried out in order to try and improve the seismic strength and performance of reinforced concrete exterior beam–column joints by applying embedded carbon fiber-reinforced polymer (CFRP) bars combined with CFRP sheets. CFRP bars have a flat-typed hexagonal cross-section. Specimens of reinforced concrete exterior beam–column joints were manufactured based on a newly developed strengthening method by applying embedded CFRP hexagonal bars combined with externally bonded CFRP sheets, and tested for comparison with the specimen of a conventional reinforced concrete exterior beam–column joint. The newly developed design approach could minimize damage and improve the overall structural performances of beam–column joints under cyclic load reversals

Lipschitz Continuous Autoencoders in Application to Anomaly Detection

Anomaly detection is the task of finding abnormal data that are distinct from normal behavior. Current deep learning-based anomaly detection methods train neural networks with normal data alone and calculate anomaly scores based on the trained model. In this work, we formalize current practices, build a theoretical framework of anomaly detection algorithms equipped with an objective function and a hypothesis space, and establish a desirable property of the anomaly detection algorithm, namely, admissibility. Admissibility implies that optimal autoencoders for normal data yield a larger reconstruction error for anomalous data than that for normal data on average. We then propose a class of admissible anomaly detection algorithms equipped with an integral probability metric-based objective function and a class of autoencoders, Lipschitz continuous autoencoders. The proposed algorithm for Wasserstein distance is implemented by minimizing an approximated Wasserstein distance with a penalty to enforce Lipschitz continuity with respect to Wasserstein distance. Through ablation studies, we demonstrate the efficacy of enforcing Lipschitz continuity of the proposed method. The proposed method is shown to be more effective in detecting anomalies than existing methods via applications to network traffic and image datasets(1).N

Experiments and failure analysis of SHCC and reinforced concrete composite slabs

For all types of concrete structures, controlling of cracking, as well as the enhancement of serviceability and ultimate flexural capacity are important issues for deck slabs. This study presents an experimental campaign and accompanying nonlinear analysis of a series of Strain Hardening Cementitious Composite (SHCC) and reinforced concrete slab systems, simply-supported and subjected to four-point loading. In order to improve flexural performance both at the service and ultimate limit states, an SHCC layer with thickness of 150–400 mm was placed on the soffit of the composite slab; the SHCC was manufactured using two different processes, namely cast-in-situ SHCCs and extruded precast SHCC panel. Nonlinear analysis of SHCC and reinforced concrete slabs was also carried out to predict moment and curvature as well as deflections of the slab systems. The developed slab systems were found to have enhanced performance with regard to both at serviceability and flexural capacity, compared to the conventional reinforced concrete slab

Unconventional spin-phonon coupling via the Dzyaloshinskii???Moriya interaction

Spin-phonon coupling (SPC) plays a critical role in numerous intriguing phenomena of transition metal oxides (TMOs). In 3d and 4d TMOs, the coupling between spin and lattice degrees of freedom is known to originate from the exchange interaction. On the other hand, the origin of SPC in 5d TMOs remains to be elucidated. To address this issue, we measured the phonon spectra of the 5d pyrochlore iridate Y 2 Ir 2 O 7 using optical spectroscopy. Three infrared-active phonons soften below the N??el temperature of T N ??? 170 K, indicating the existence of strong SPC. Simulations using density functional theory showed that the coupling is closely related to the Ir???O???Ir bond angle. A tight-binding model analysis reveals that this SPC is mainly mediated by the Dzyaloshinskii???Moriya interaction rather than the usual exchange interaction. We suggest that such unconventional SPC may be realized in other 5d TMOs with non-collinear magnetic order

Microstructure and Glass Phase of Inorganic Binder Coated on Mold for Thin Casting

A new dual dipping process has been introduced for the increase in the fracture strength of casting mold through the effective glassification of inorganic binder precursors. Two different dipping processes have been employed to investigate the reactivity of the precursors. Process I is that the substrate was coated with a sodium oxide (Na2O) precursor through dipping in the solution, and then a silicon dioxide (SiO2) precursor was coated onto the substrate coated with the Na2O precursor. Process II is the inverse coating sequence for process I. In the case of the mold prepared by process I, the glass phase converted from the precursors is uniformly observed at the surface of the particle and the interface between particles, compared with that by process II, inducing that the fracture strength of the mold prepared by process I is significantly improved. In addition, when the PDMS without a sol-gel reaction was used as the SiO2 precursor, especially in process II, the glass phase is not absolutely observed at the surface of the particle owing to the evaporation of PDMS and Na ion during the heat treatment, resulting in the collapse of the mold sample after the heat treatment

A Case of Successful Treatment of Stomal Variceal Bleeding with Transjugular Intrahepatic Portosystemic Shunt and Coil Embolization

Variceal bleeding from enterostomy site is an unusual complication of portal hypertension. The bleeding, however, is often recurrent and may be fatal. The hemorrhage can be managed with local measures in most patients, but when these fail, surgical interventions or portosystemic shunt may be required. Herein, we report a case in which recurrent bleeding from stomal varices, developed after a colectomy for rectal cancer, was successfully treated by placement of transjugular intrahepatic portosystemic shunt (TIPS) with coil embolization. Although several treatment options are available for this entity, we consider that TIPS with coil embolization offers minimally invasive and definitive treatment