• Geomechanics and Engineering
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• v.9 no.6
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• pp.793-813
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• 2015

Characterization of discontinuous media is an endeavor that poses great challenge to engineers in practice. Since the inherent defects in cracked domains can substantially influence material resistance and govern its behavior, a lot of work is dedicated to efficiently model such effects. In order to overcome difficulties of material instability problems, one needs to comprehensively represent the geometry of cracks along with their impact on the mechanical properties of the intact material. In the present study, stress-strain results from laboratory experiments on Inada granite was used to derive crack tensor as a tool for the evaluation of fractured domain stability. It was found that the formulations proposed earlier could satisfactorily be employed to attain crack tensor via the invariants of which judgment on cracks population and induced anisotropy is possible. The earlier criteria based on crack tensor analyses were reviewed and compared to the results of the current study. It is concluded that the geometrical parameters calculated using mechanical properties could confidently be used to judge the anisotropy as well as strength of the cracked domain.

• Journal of Agricultural Extension & Community Development
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• v.26 no.2
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• pp.69-84
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• 2019

Recently rural healing tourism has been attracting tourists' interest in relieving mental stress and restoring physical daily life with nature-friendly experience. The purpose of this study is to explore the urgent problems and challenges of rural healing tourism by conducting focus group interview(FGI) with experts. Fourteen experts were interviewed with a semi-structured questionnaire. From the interview data, six themes were identified for direction of healing tourism development. The results of the study are as follows; The area of rural healing tourism can be explained within the framework of health tourism. As for the difference between rural tourism and healing tourism, rural tourism is expected to enhance physical and mental relaxation, daily restoration, and health promotion if rural tourism expects the understanding and experience of agricultural and rural life, and educational effect. The core components of rural healing tourism were operators' expertise, program with rurality, ecological environment, and storytelling. The findings of this paper implicate the underlying dimension of rural healing tourism from a experts' perspective.

• Journal of English Language & Literature
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• v.64 no.4
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• pp.629-649
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• 2018

To date, one of the prevailing criticisms of Daniel Defoe's Robinson Crusoe has seen the adventure novel as a celebration of the rise of mercantile capitalism and the beginnings of colonialism. From this point of view, the Englishman has often been interpreted as an early embodiment of the concept of the sovereign economic subject. Prominent social critics who took up this interpretation have included Karl Marx, Max Weber, and Jean-Jacques Rousseau. Within literary studies proper, the work of Ian Watt offered perhaps the earliest version of this point of view of the novel. Influenced by both Weber and Rousseau, Ian Watt argued that Defoe's wandering protagonist embodies the rise of economic individualism. More recent criticism has tended to challenge this dominant interpretation by laying greater stress on such countervailing factors as Crusoe's mental uncertainty and inner conflict. Drawing inspiration from Fredric Jameson's diagnosis of the ills of late capitalism, this paper analyzes the ways in which Defoe's hero, rather than championing modern rationality, can in fact be seen as suffering from many forms of emotional psychosis. Robinson Crusoe can, after all, be better viewed as a contradictory multi-layered text that, despite its outward valorization of economic individualism, portrays its hero as a victim of negative capitalistic forces, a hero driven by his desire to possess but haunted by a fear of loss, a hero who flaunts inflated feelings of self-worth even as he reveals deflated notions of material insecurity and mental persecution.

• Journal of Electrochemical Science and Technology
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• v.12 no.2
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• pp.285-295
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• 2021

The inverse spinel Cobalt ferrite (CoFe₂O₄, CFO) is considered to be a promising alternative to commercial graphite anodes for lithium ion batteries (LIBs). However, the further development of CFO is limited by its unstable structure during battery cycling and low electrical conductivity. In an effort to address the challenge, we construct three-dimensional hierarchical flower-like CFO nanoclusters (CFO NCs)-decorated carbonized cotton carbon fiber (CFO NCs/CCF) composite. This structure is consisted of microfibers and nanoflower cluster composited of CFO nanoparticle, in which CCF can be used as a long-range conductive matrix, while flower-like CFO NCs can provide abundant active sites, large electrode/electrolyte interface, short lithium ion diffusion path, and alleviated structural stress. As anode materials in LIBs, the flower-like CFO NCs/CCF exhibits excellent electrochemical performance. After 100 cycles at a current density of 0.3 A g^-1, the CFO NCs/CCF delivers a discharge/charge capacity of 1008/990 mAh g^-1. Even at a high current density of 15 A g^-1, it still maintains a charge/discharge capacity of 362/361 mAh g^-1.

• Transactions of Materials Processing
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• v.32 no.3
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• pp.122-128
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• 2023

As electric vehicles (EV) have increasingly replaced the conventional vehicles with internal combustion engines (ICE), most of automotive makers are actively devoting to the technology development of EV parts. Accordingly, the manufacturing process for power source has been also shifting from engine/transmission to EV motor/reducer system. However, lack of experience in developing the EV motor still remains as a technical challenge. In this paper, we employed the forming simulation based on finite element modeling to solve this problem. In particular, in order to increase the accuracy of the forming simulation, we introduced the elastic-plastic constitutive model parameters for polymer-copper hybrid wire by investigating the individual strain-stress curves, and elastic modulus of polymer and copper. Then, the reliability of modeling procedure was confirmed by comparing the simulated results with experiments. Finally, the identified mechanical properties and finite element modeling were applied to a hairpin forming process, which involves multiple deformation paths such as bending, pressing, widening, and twisting. The proposed numerical approach can replace common experience or experiment based trials by reducing production time and cost in the future.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.126-126
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• 2022

Climate change has continued to impact meteorological factors like rainfall in many countries including Nigeria. Thus, altering the rainfall patterns which subsequently affect the crop yield. Maize is an important cereal grown in northern Nigeria, along with sorghum, rice, and millet. Due to the challenge of water scarcity during the dry season, it has become critical to design appropriate strategies for planning, developing, and management of the limited available water resources to increase the maize yield. This study, therefore, determines the quantity of water required to produce maize from planting to harvesting and the impact of drought on maize during different growth stages in the region. Rainfall data from six rain gauge stations for a period of 36 years (1979-2014) was considered for the analysis. The standardized precipitation and evapotranspiration index (SPEI) is used to evaluate the severity of drought. Using the CROPWAT model, the evapotranspiration was calculated using the Penman-Monteith method, while the crop water requirements (CWRs) and irrigation scheduling for the maize crop was also determined. Irrigation was considered for 100% of critical soil moisture loss. At different phases of maize crop growth, the model predicted daily and monthly crop water requirements. The crop water requirement was found to be 319.0 mm and the irrigation requirement was 15.5 mm. The CROPWAT 8.0 model adequately estimated the yield reduction caused by water stress and climatic impacts, which makes this model appropriate for determining the crop water requirements, irrigation planning, and management.

• International conference on construction engineering and project management
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• 2020.12a
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• pp.303-312
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• 2020

Safety culture is a collection of the beliefs, perceptions and values that employees share in relation to risks within an organisation. On the other hand, a resilient safety culture (RSC) means a culture with readiness of the organisation to respond effectively under stress, bounce back from shocks and continuously learn from them. RSC helps organisations to protect their interest which can be attributed to behavioural, psychological and managerial capabilities of the organization. Quantification of the degree of resilience in an organisation's safety culture can provide insights about the strong and weak links of the organisation's overall health and safety situation by identifying potential causes of system or sub-system failure. One of the major challenges of quantification of RSC is that the attributes that determine RSC need to be measured through constructs and indicators which are complex and often interrelated. In this paper, we address this challenge by applying a fault tree analysis (FTA) technique which can help analyse complex and interrelated constructs and indicators. The fault tree model of RSC is used to evaluate resilience levels of two organisations with remote and urban locations in order to demonstrate the failure path of the weak links in the RSC model.

• Korean Journal of Construction Engineering and Management
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• v.24 no.6
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• pp.81-90
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• 2023

Climate change has resulted in increased frequency and intensity of heat waves, which poses a significant threat to the health and safety of construction workers, particularly those engaged in labor-intensive and heat-stress vulnerable working environments. To address this challenge, this study aimed to propose an interpretable machine learning approach for forecasting personal heat strain by considering the cumulative effect of heat exposure as a situational variable, which has not been taken into account in the existing approach. As a result, the proposed model, which incorporated the cumulative working time along with environmental and personal variables, was found to have superior forecast performance and explanatory power. Specifically, the proposed Multi-Layer Perceptron (MLP) model achieved a Mean Absolute Error (MAE) of 0.034 (℃) and an R-squared of 99.3% (0.933). Feature importance analysis revealed that the cumulative working time, as a situational variable, had the most significant impact on personal heat strain. These findings highlight the importance of systematic management of personal heat strain at construction sites by comprehensively considering the cumulative working time as a situational variable as well as environmental and personal variables. This study provided a valuable contribution to the construction industry by offering a reliable and accurate heat strain forecasting model, enhancing the health and safety of construction workers.

• Coupled systems mechanics
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• v.12 no.5
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• pp.429-444
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• 2023

The comprehension and structural modeling of masonry constructions is fundamental to safeguard the integrity of built cultural assets and intervene through adequate actions, especially in earthquake-prone regions. Despite the availability of several modeling strategies and modern computing power, modeling masonry remains a great challenge because of still demanding computational efforts, constraints in performing destructive or semi-destructive in-situ tests, and material uncertainties. This paper investigates the shear behavior of masonry walls by applying a plane-stress FE continuum model with the Modified Masonry-like Material (MMLM). Epistemic uncertainty affecting input parameters of the MMLM is considered in a probabilistic framework. After appointing a suitable probability density function to input quantities according to prior engineering knowledge, uncertainties are propagated to outputs relying on gPCE-based surrogate models to considerably speed up the forward problem-solving. The sensitivity of the response to input parameters is evaluated through the computation of Sobol' indices pointing out the parameters more worthy to be further investigated, when dealing with the seismic assessment of masonry buildings. Finally, masonry mechanical properties are calibrated in a probabilistic setting with the Bayesian approach to the inverse problem based on the available measurements obtained from the experimental load-displacement curves provided by shear compression in-situ tests.

• Korean Journal of Poultry Science
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• v.38 no.3
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• pp.213-223
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• 2011

This study was conducted to test the efficacy of plum (Prunus mume) and red ginseng (Panax ginseng C.A Meyer) marc as stress inhibitors under heat stress and lipopolysaccharide (LPS) challenge in broilers by investigating their effects on blood biochemical parameters, immunoglobulin concentration and splenic cytokine mRNA expressions. A total of one hundred ninety-two 1-d-old male broiler chicks (Ross 308) were divided into 2 stress conditions (heat and LPS) experiments. Each experiment was divided into 4 treatment groups with 8 replicates of 3 birds in each group. NC (negative control, no immune substances), PC (positive control, 25 ppm ${\beta}$-glucan), PM (1% plum marc) and RGM (3% red ginseng marc) treatments were administered with respective substance through water supplementation. During heat stress, The Ca/Mg ratio in PM and RGM was significantly decreased in comparison with that of NC (P<0.05). The immunoglobulin M was significantly lower in PM than in NC (P<0.05). Expression patterns of splenic cytokine mRNAs (IL-1, IL-2 and IL-6) were similar over the treatment. Expression rates of IL-1 and IL-2 in PM were significantly decreased in comparison with NC. Also, expression rates of IL-1, IL-2 and IL-6 were significantly lower in RGM than in NC (P<0.05). In conclusion, the dietary supplementation of plum and red ginseng marc improved coping ability to heat stress by preventing Ca/Mg ratio increment and by inhibiting inflammatory response in broiler chicks. However, it is necessary to determine optimal dietary level of red ginseng marc for improving growth performances in broiler chickens. These results suggest the possibility that plum and red ginseng marc could be used as the stress inhibitor under heat stress and inflammatory response in broiler chicks.