In conventional construction practices, roof-parapet junction structures inevitably disrupt the insulation installation's continuity, leading to energy loss and thermal bridging. To address this issue, parapet thermal breaks were installed to interrupt the heat flow between the roof and the parapet, effectively preventing thermal bridging and energy loss and thereby reducing overall energy loss in buildings. This study equipped three experimental specimens with the developed parapet thermal breaks to verify their structural performance. These specimens were subjected to unidirectional loading under displacement-controlled conditions. The structural performance of these insulation structures was evaluated by comparing and analyzing the test results with corresponding analytical studies conducted using a finite element analysis program. In addition, five analytical models with varying parameters of the parapet thermal breaks were developed and compared against the baseline model. Consequently, the most efficient shape of the parapet thermal break was determined.

Copper, silver, and gold-reduced graphene oxide nanocomposite (Cu-rGO, Ag-rGO, and Au-rGO) were fabricated via the hydrothermal method, which shows unique physiochemical properties. Environment friendly electromagnetic radiation was employed to synthesize rGO from GO. The nonlinear optical phenomenon of noble metal decorated rGO is predominantly due to excited state absorption, which arises from surface plasmon resonance and increases in defects at the surface due to Cu, Ag, and Au incorporation. It is found that the third-order nonlinear absorption coefficient was in the order of 10− 10 m/W, with notable enhancements in the third-order properties of Au-rGO compared to other nanocomposites and their respective counterparts. Functionalizing rGO induces defect states ( sp3), increasing NLO response. Cu, Ag, and Au exhibit higher Surface-Enhanced Raman Scattering (SERS) activity due to rGO-induced structural modifications. SERS signals are influenced by dominant signals from Au nanorods. The electronic structures for pure and doped rGO were investigated through Density Functional Theory (DFT). The computed partial density of states (PDOS) confirms the enhancement of the state in Au-doped rGO is due to the charge transference from Au to C 2p orbital. The optical absorption spectra and PDOS reveal the possibility of free carrier absorption enhancement in Au which validates experimentally observed higher two-photon absorption (β) value of Au-doped rGO. The tuning of nonlinear optical and SERS behaviour with variation in the noble metal upon rGO provides an easy way to attain tuneable properties which are exceedingly required in both optoelectronics and photonics applications.

The biggest jewel beetle in Korea, Chrysochroa coreana, has been nominated as the Natural Monument No. 496 and also classified as Category I of Endangered Species by the Red Data Book. Due to the invisible feature of a saproxylic larval hood inside the host tree for years, the whole life history was hitherto been unknown to the academic world. In order to clarify the period of larval-hood and record images of the process of the final stage of emergence, we obtained sample eggs from two mated couples of adults that emerged from a dead tree of Celtis sinensis on Wando Island, which is well-known as the habitat of C. coreana. Larvae were hatched on four pieces of timber (Celtis aurantiaca) in July 2018 and kept in a growth chamber under the conditions of 25°C, 65% humidity, and in a 12-hour light/dark cycle. The development of larvae was monitored via the non-destructive C/T method every month. Six adults were emerged between February and March 2024. As a result, we obtained the fact that the larval period of C. coreana is minimum 66 months (5.5 years) under lab conditions.

The significance of this study lies in addressing critical issues prevalent in the worldwide construction sector, particularly concerning the durability and sustainability of cement-based materials. Plain cement composites commonly suffer from deficiencies in tensile strength and strain capacity, resulting in the formation of nano-cracks under relatively low tensile loads. These nano- cracks pose a significant challenge to the longevity and resilience of cement matrices, contributing to structural degradation and reduced service life of infrastructure. To mitigate these challenges, the integration of cellulose nanofibers (CNF) as reinforcements in cement composites presents a promising solution. CNF, renowned for their exceptional material properties including high stiffness, tensile strength, and corrosion resistance, offer the potential to significantly enhance the mechanical performance and durability of cement-based materials. Through systematic experimentation, this study investigates the effects of CNF reinforcement on the mechanical properties of cement composites. By leveraging ultrasonically dispersion techniques, CNF extracted from bamboo, broad leaf, and kenaf are uniformly dispersed within the cement matrix at varying concentrations. Compressive and flexural tests are subsequently conducted to evaluate the impact of CNF on the strength characteristics of the cement composites. By elucidating the efficacy of CNF reinforcement through rigorous experimentation, this study aims to provide valuable insights into the development of construction materials with improved durability and sustainability. Ultimately, this research contributes to addressing critical challenges in the construction industry, offering potential solutions to enhance the performance and longevity of cement-based infrastructure.

The study investigates how the presence of blockchain technology affects social fairness and selfish monetary decisions. Based on the assumption that blockchain technology enhances transparency and traceability in social exchanges, the study predicts that individuals will make less selfish decisions when blockchain is present. To test these predictions, the study conducted three experiments using a modified version of the dictator game scenario where participants decide how to divide a sum of money among themselves. In Study 1, the results show that individuals took less money for themselves and allocated more to the third player when blockchain technology was present, and the importance of social fairness was higher under the blockchain-presence condition. The mediation analysis indicates that the increase in social fairness mediates the effect of blockchain technology on monetary decisions. Study 2 replicated Study 1 with real monetary incentives. The results showed that individuals took less money for themselves only under the blockchain-image condition, and the importance of social fairness was higher only under the blockchain-image condition. Study 3 examined the moderating effect of the first player's allocation on participants' behavior under the presence or absence of blockchain technology. The study provides empirical evidence that blockchain technology can positively influence social fairness and reduce selfish monetary decisions. The findings have implications for policymakers and blockchain developers to design and implement blockchain systems that promote transparency and traceability in social exchanges, thereby enhancing social fairness.

본 연구에서는 가설 강교에 사용되는 조립식 거더-교각 접합부에 대한 새로운 설계를 제안하였다. 새로운 접합부는 모듈의 각 부분을 공장에서 용접하여 제작한 후 현장에서 용접 대신 볼트 접합부를 사용하도록 구성하여 현장에서 모듈을 신속 하게 조립하도록 구성하였다. 이 새롭게 제안된 거더-교각 접합부의 구조적 성능을 평가하기 위해 정적 거동, 연성 성능 및 회 전 성능을 분석하는 실험을 수행하였다, 실험결과 제안된 볼트 접합부는 기존의 용접 체결부에 비해 정적 지지력, 연성 거동 및 회전 성능에서 우수한 성능을 보여주었다. 비록 볼트 체결부의 강성이 용접 체결부보다 다소 작지만, 체결부의 연성 성능이나 정적 지지력에 큰 영향을 미치지 않았으며, 안전성 향상, 빠른 조립 및 분해, 건설 공기 단축 등의 유리한 특성으로 인해 가설 교량 건설에 적합한 것으로 평가되었다.

Composite materials offer distinct and unique properties that are not naturally inherited in the individual materials that make them. One of the most attractive composites to manufacture is the aluminum alloy matrix composite, because it usually combines easiness of availability, light weight, strength, and other favorable properties. In the current work, Powder Metallurgy Method (PMM) is used to prepare Al2024 matrix composites reinforced with different mixing ratios of yttrium oxide (Y2O3) particles. The tests performed on the composites include physical, mechanical, and tribological, as well as microstructure analysis via optical microscope. The results show that the experimental density slightly decreases while the porosity increases when the reinforcement ratio increases within the selected range of 0 ~ 20 wt%. Besides this, the yield strength, tensile strength, and Vickers hardness increase up to a 10 wt% Y2O3 ratio, after which they decline. Moreover, the wear results show that the composite follows the same paradigm for strength and hardness. It is concluded that this composite is ideal for application when higher strength is required from aluminum composites, as well as lighter weight up to certain values of Y2O3 ratio.

In this study, the out-of-plane seismic resistance of lightly-reinforced existing walls strengthened with thick RC jacket was investigated. The thick RC jacket with a thickness of 500 mm was placed at one side of the thin existing wall with a thickness of 150 mm. At the interface between the wall and RC jacket, a tee-shaped steel section with a number of anchor bolts and dowel bars was used as the shear connector. To investigate the connection performance and strengthening effects, the cyclic loading tests of four jacketed wall specimens were performed. The tests showed that the flexural strength of the jacketed walls under out-of-plane loading was significantly increased. During the initial behavior, the tee shear connector transferred forces successfully at the interface without slip. However, as the cracking, spalling, and crushing of the concrete increased in the exiting walls, the connection performance at the interface was significantly degraded and, consequently, the strength of the jacketed walls was significantly decreased. The flexural strength of the jacketed walls with tee shear connector was estimated considering the full and partial composite actions of the tee shear connector.

The research presented in this manuscript is centered on examining how social sponsorship can be made more commercially effective. To this end, the effects of two leveraging factors are explored by means of an experiment: the extent to which the social sponsorship is seen by consumers as legitimate, and that to which the sponsor is perceived as sincere. The results show that these two factors have a positive and statistically significant impact on consumers’ intentions to purchase the sponsor’s products. In addition, they show that the legitimacy of a sponsorship is enhanced when the cause and its sponsor are congruent, and that the sponsor’s sincerity increases when the sponsorship is combined with philanthropic investments, either in sequence (i.e., philanthropy followed by sponsorship) or simultaneously. These results are discussed in the context of the literature on social sponsorship, and managerial implications for firms that contemplate using social sponsorship as a marketing communication strategy are derived.

An experimental investigation is performed to study the effect of jet to plate spacing and low Reynolds number on the local heat transfer distribution to normally impinging submerged circular air jet on a smooth and flat surface. A single jet from a straight circular nozzle of length to diameter ratio(l/d) of 83 is tested. Reynolds number based on nozzle exit condition is varied between 500 and 8,000 and jet to plate spacing between 0.5 and 8 nozzle diameter. The local het transfer characteristics are obtained using thermal images from infrared thermal imaging technique. It was observed that at lower Reynolds numbers, the effect of jet to plate distances covered during the study on the stagnation point Nusselt numbers is minimal. At all jet to plate distances, the stagnation point Nusselt numbers decrease monotonically with the maximum occurring at a z/d of 0.5 as opposed to the stagnation point Nusselt numbers at high Reynolds numbers which occur around a z/d of 6.

In order to provide the basis data for broad use and safe design of carbon fiber reinforced plastic, this paper aims at investigating the fracture behavior on CFRP specimen composed of one directional fiber through three point bending test. On the basis of experimental result, the improvement of composite layer specimen can be secured with the other data to compare the existing specimen. The fracture behavior happened at the experimental procedure is investigated in this study. The maximum loads of 1200 N, 1700N and 1600N are shown respectively at the specimens with the layer angles of 30°, 45° and 60°. The highest load is shown at the layer angle of 60° among all specimens and the longest displacement is maintained until each of the layer structure is broken down. The fracture due to the force applied from the outside can be prevented by applying the result of this study to the real structure. As structural safety can be evaluated and anticipated through this study, it is thought that the safe design is devoted.

There are a number of construction methods to build spatial structures such as erection method, Element method, Block method, Sliding method, Lift-up method and Push-up method. These methods are uneconomical and low accuracy, and require long construction duration because of a need of a scaffold or a tower crane to build spatial roof frame. In this study, the construction method to erect a truss structure was proposed as an economical and easy installation method. The proposed method has end hinges of keel truss and winches with horizontal cable. This method makes safe and accurate production and reduces construction duration because trusses are built on the floor or supporter. The goal of this study is to verify the validity of construction method by building scale model using the proposed method.

최근 국내에서는 원자력발전소의 모듈화 공법에 적용하기 위하여 SC(steel plate concrete) 구조를 개발하는 연구를 진행하고 있다. 이 연구에서는 전단보강이 없는 비보강 SC 전단벽의 횡방향 내진성능 및 강성특성에 대하여 분석하기 위하여 전단벽 모형시편을 제작하고, 이를 대상으로 정적가력실험을 수행하였다. 실험 결과를 이용하여, 이 논문에서는 비보강 SC 구조의 횡력에 대한 파괴모드의 유형을 분석하고, 단면강도와 부재의 강성 특성을 검토하였다. 그리고 SC 구조용 설계기준에서 제시하는 단면의 강도 계산식과실험결과를 비교하였다. 연구결과, 비보강 SC 전단벽의 파괴 형태의 하나는 콘크리트와 강판의 부착 상실로 인한 휨전단파괴라는 사실을발견하였다. SC 구조 전단벽의 벽체 길이방향 거동은 파괴 시까지 벽체 외측의 강판이 내부 콘크리트를 구속하는 효과를 기대할 수 있으므로 연성능력이 향상되는 것이 확인되었다

FRP Sheet와 비좌굴가새를 적용한 보-기둥 접합부의 보강효과를 평가하기 위하여 보-기둥 접합부 실험체에 축력 및 반복 횡가력을 가하여 실험을 수행하였다. 동일한 크기의 6개의 실험체를 제작하였으며 FRP Sheet의 종류 및 비좌굴 가새의 유무를 변수로 하였다. 실험체의 파괴양상 및 최대하중, 연성지수, 에너지소산능력의 측면에서 실험결과를 분석하였다. 실험결과 CFRP Sheet와 비좌굴가새를 혼용한 보강방법이 가장 우수한 성능을 나타냈다.

본 연구는 반복 횡하중 하에서 CFRP(Carbon Fiber Reinforced Polymer) Sheet로 보강된 철근콘크리트 프레임면내 조적벽체의 전단내력을 평가하여 국내 조적벽체 학교 건축물에 적합한 CFRP Sheet 보강 방안을 제안하는 것에 그 목적이 있다. 조적 허리벽이 있는 1층, 1경간, 1/2 스케일의 시험체를 4개 제작하여 CFRP Sheet의 보강량을 변수로 실험을 수행하였으며 이를 통하여 보강량에 따른 강도와 강성의 변화를 분석하였다. 실험 결과 CFRP Sheet는 시험체의 내력과 강성을 향상시켰으며 특히 기둥과 조적벽을 모두 보강하는 방법을 통한 보강방법에 있어 그 적용성을 확인할 수 있었다.