Chloride-Binding Capacity of Portland Cement Paste Blended with Synthesized CA 2

A chloride-binding capacity is the major factor to mitigate the ingress of chloride into concrete. This paper presents the chloride-binding capacity of Portland cement paste containing synthesized CA2 (CaO·2Al2O3). The CA2 was synthesized in the high-temperature furnace and characterized by X-ray diffraction for inspecting the purity. The synthesized CA2 was substituted for Portland cement by 0%, 5%, and 10% by weight, and the NaCl solution was used as an internal chloride, which is assumed as a total chloride. The chloride-binding capacity of cement paste was calculated from a water-soluble chloride extraction method by the application of the Langmuir isotherm equation. And the hydration products were analyzed using X-ray diffraction and thermogravimetric analysis. We demonstrate that the CA2 increases an AFm phase in the Portland cement system, and the incorporation of CA2 consequently enhances the chloride-binding capacity of cement paste samples

VisIRR: Interactive Visual Information Retrieval and Recommendation for Large-scale Document Data

Research areas: Machine learning, Data mining, Information visualization, Visual analytics, Text visualization.We present a visual analytics system called VisIRR, which is an interactive visual information retrieval and recommendation system for document discovery. VisIRR effectively combines both paradigms of passive pull through a query processes for retrieval and active push that recommends the items of potential interest based on the user preferences. Equipped with efficient dynamic query interfaces for a large corpus of document data, VisIRR visualizes the retrieved documents in a scatter plot form with their overall topic clusters. At the same time, based on interactive personalized preference feedback on documents, VisIRR provides recommended documents reaching out to the entire corpus beyond the retrieved sets. Such recommended documents are represented in the same scatter space of the retrieved documents so that users can perform integrated analyses of both retrieved and recommended documents seamlessly. We describe the state-of-the-art computational methods that make these integrated and informative representations as well as real time interaction possible. We illustrate the way the system works by using detailed usage scenarios. In addition, we present a preliminary user study that evaluates the effectiveness of the system

Multiplexers and Antennas Based on Metamaterial Transmission Line

Metamaterial transmission lines are able to control the phase response in the circuit, thereby making it possible to achieve multi-band characteristic in guided structures and full beam scanning ability in leaky-wave antenna applications. Isolation circuits use multi-band trait of a metamaterial transmission line for having infinite impedance at multiple frequencies. With isolation circuits, it is possible to connect microwave filters for having unique property, so called multiplexing functionality. This new approach provides unique advantageous features beneficial to system designer. For instance, there is no need to modify the components (filters and multiplexers) used in the system. Also, the design process is straightforward.Substrate integrated waveguide (SIW) is a novel guided-wave structure developed in recent years in microwave and millimeter wave areas. It can be synthesized on a planar substrate with linear periodic arrays of metallic vias by planar circuit processes. SIW has significant advantages such as low insertion loss, low cost and strong integration ability with other planar circuits. Based on the SIW technique and the metamaterial transmission line concept, circular polarized SIW leaky-wave antennas are designed and presented. The proposed frequency scanning antennas provide circular polarized fields using a single radiating transmission line, which can avoid the complexity of conventional approach

Chloride Ion Adsorption Capacity of Anion Exchange Resin in Cement Mortar

This paper presents the effect of anion exchange resin (AER) on the adsorption of chloride ions in cement mortar. The kinetic and equilibrium behaviors of AER were investigated in distilled water and Ca(OH)2 saturated solutions, and then the adsorption of chloride ions by the AER in the mortar specimen was determined. The AER was used as a partial replacement for sand in the mortar specimen. The mortar specimen was coated with epoxy, except for an exposed surface, and then immersed in a NaCl solution for 140 days. The chloride content in the mortar specimen was characterized by energy dispersive X-ray fluorescence analysis and electron probe microanalysis. The results showed that the AER could adsorb the chloride ions from the solution rapidly but had a relatively low performance when the pH of its surrounding environment increased. When the AER was mixed in the cement mortar, its chloride content was higher than that of the cement matrix around it, which confirms the chloride ion adsorption capacity of the AER

Development of IoT-Based Particulate Matter Monitoring System for Construction Sites

Particulate matters (PMs) generated on construction sites can pose serious health risks to field workers and residents living near construction sites. PMs are generated in a wide range of locations; therefore, they must be managed in real time at various locations within construction sites for practical management of the PMs. However, no such systems exist currently. Therefore, this study aims to develop a system that can manage PMs in real time at multiple locations in a construction site using the Internet of Things technology. Accordingly, measuring instrument, network, and program services were developed as system components, while considering the characteristics of construction sites, and the construction site PM monitoring system was developed by integrating these components. Finally, performance certification and field application tests were performed to verify the developed system. The construction site PM monitoring system (CPMS) achieved grade 1 for reproducibility, relative precision, and data acquisition rate, and grade 2 for accuracy and coefficient of determination. Thus, it received a performance certification of grade 2, in total. In particular, regarding accuracy, which is a shortcoming of the light-scattering method and represents the accuracy of measurements, the CPMS was found to have an accuracy of 74.2%