Evaluation of Toluene Adsorption Performance of Mortar Adhesives Using Porous Carbon Material as Adsorbent

Porous carbon materials are advantageous in adsorbing pollutants due to their wide range of specific surface areas, pore diameter, and pore volume. Among the porous carbon materials in the current study, expanded graphite, xGnP, xGnP C-300, xGnP C-500, and xGnP C-750 were prepared as adsorbent materials. Brunauer–Emmett–Teller (BET) analysis was conducted to select the adsorbent material through the analysis of the specific surface area, pore size, and pore volume of the prepared porous carbon materials. Morphological analysis using SEM was also performed. The xGnP C-500 as adsorbent material was applied to a mortar adhesive that is widely used in the installation of interior building materials. The toluene adsorption performances of the specimens were evaluated using 20 L small chamber. Furthermore, the performance of the mortar adhesive, as indicated by the shear bond strength, length change rate, and water retention rate, was analyzed according to the required test method specified in the Korean standards. It was confirmed that for the mortar adhesives prepared using the xGnP C-500 as adsorbent material, the toluene adsorption performance was excellent and satisfied the required physical properties

Chlorophyll Fluorescence Imaging for Environmental Stress Diagnosis in Crops

The field of plant phenotype is used to analyze the shape and physiological characteristics of crops in multiple dimensions. Imaging, using non-destructive optical characteristics of plants, analyzes growth characteristics through spectral data. Among these, fluorescence imaging technology is a method of evaluating the physiological characteristics of crops by inducing plant excitation using a specific light source. Through this, we investigate how fluorescence imaging responds sensitively to environmental stress in garlic and can provide important information on future stress management. In this study, near UV LED (405 nm) was used to induce the fluorescence phenomenon of garlic, and fluorescence images were obtained to classify and evaluate crops exposed to abiotic environmental stress. Physiological characteristics related to environmental stress were developed from fluorescence sample images using the Chlorophyll ratio method, and classification performance was evaluated by developing a classification model based on partial least squares discrimination analysis from the image spectrum for stress identification. The environmental stress classification performance identified from the Chlorophyll ratio was 14.9% in F673/F717, 25.6% in F685/F730, and 0.209% in F690/F735. The spectrum-developed PLS-DA showed classification accuracy of 39.6%, 56.2% and 70.7% in Smoothing, MSV, and SNV, respectively. Spectrum pretreatment-based PLS-DA showed higher discrimination performance than the existing image-based Chlorophyll ratio

Thermal Performance Evaluation of Fatty Acid Ester and Paraffin Based Mixed SSPCMs Using Exfoliated Graphite Nanoplatelets (xGnP)

Phase change materials (PCMs) have been used in various fields including the materials of buildings. In this research, mixed shape-stabilized PCMs (Mixed SSPCMs) were prepared by impregnating coconut oil and n-hexadecane into exfoliated graphite nanoplatelets (xGnP) through a vacuum impregnate method. Coconut oil is fatty acid ester PCM which is relatively economical in comparison to other PCMs, and n-hexadecane is paraffin PCM that has high latent heat capacity. Drawbacks include leakage in a liquid state and low thermal conductivity resolved by xGnP. When preparing Mixed SSPCMs, coconut oil and n-hexadecane were impregnated at different proportions, namely 70:30, 50:50, 30:70 wt %. Mixed SSPCMs were analyzed through SEM, FT-IR, DSC, TGA and TCi. As a result, we confirmed the microstructure, chemical stability, thermal properties, thermal stability and thermal conductivity of Mixed SSPCMs. Latent heat capacity of Mixed SSPCMs were 89.06, 104.30 and 124.50 J/g while those of SSPCMs containing single PCM were 82.34 and 96.40 J/g. Thermal conductivity of Mixed SSPCMs was more than 284% higher than that of pure coconut oil and n-hexadecane. Finally, we confirmed that coconut oil and n-hexadecane were impregnated into xGnP, and the Mixed SSPCMs have high thermal durability

Performances and properties of steel and composite prestressed tendons – A review

The primary drawback of concrete lies in its low tensile strength, prompting the development of various solutions to enhance this aspect. A notable approach is the utilization of Prestressed Reinforced Concrete (PRC) with tendons, aimed at bolstering its tensile strength. As the use of diverse tendon types in the PRC continues to surge, a review becomes imperative to delve into this evolution. Therefore, this study delved into the engineering characteristics, performance, and evolution of different tendon varieties, encompassing both steel and composite options. Despite certain drawbacks associated with employing composite materials such as Fiber Reinforced Polymer (FRP) tendons - such as heightened costs, limited availability of composite materials, and intricate manufacturing processes - there are distinct advantages and merits to incorporating FRP composite tendons in the realm of construction. In this respect, Carbon FRP tendons exhibited superior strength, comparable to their steel counterparts. Glass FRP tendons, lacking metallic components, possessed non-magnetic properties, rendering them resistant to corrosion. Additionally, Aramid FRP tendons boasted low flammability and exceptional resistance to elevated temperatures. Lastly, Basalt FRP tendons offered sustainability, rust resistance, and non-corrosiveness. The findings derived from this review study serve as a valuable resource for researchers seeking to advance the applications of steel tendons and FRP composite materials within the construction industry