• Mycobiology
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• 제44권3호
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• pp.162-170
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• 2016

In this paper, we demonstrate the ability of Arabidopsis thaliana to detect different mixtures of volatile organic compounds (VOCs) emitted by the common indoor fungus, Aspergillus versicolor, and demonstrate the potential usage of the plant as a bioindicator to monitor fungal VOCs in indoor air. We evaluated the volatile production of Aspergillus versicolor strains SRRC 108 (NRRL 3449) and SRRC 2559 (ATCC 32662) grown on nutrient rich fungal medium, and grown under conditions to mimic the substrate encountered in the built environment where fungi would typically grow indoors (moist wallboard and ceiling tiles). Using headspace solid phase microextraction/gas chromatography-mass spectrometry, we analyzed VOC profiles of the two strains. The most abundant compound produced by both strains on all three media was 1-octen-3-ol. Strain SRRC 2559 made several terpenes not detected from strain SRRC 108. Using a split-plate bioassay, we grew Arabidopsis thaliana in a shared atmosphere with VOCs from the two strains of Aspergillus versicolor grown on yeast extract sucrose medium. The VOCs emitted by SRRC 2559 had an adverse impact on seed germination and plant growth. Chemical standards of individual VOCs from the Aspergillus versicolor mixture (2-methyl-1-butanol, 3-methyl-1-butanol, 1-octen-3-ol, limonene, and ${\beta}-farnesene$), and ${\beta}-caryophyllene$ were tested one by one in seed germination and vegetative plant growth assays. The most inhibitory compound to both seed germination and plant growth was 1-octen-3-ol. Our data suggest that Arabidopsis is a useful model for monitoring indoor air quality as it is sensitive to naturally emitted fungal volatile mixtures as well as to chemical standards of individual compounds, and it exhibits relatively quick concentration- and duration-dependent responses.

• Steel and Composite Structures
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• 제50권3호
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• pp.299-318
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• 2024

The main objective of this paper is to compute the far-field acoustic radiation (sound radiation) of functionally graded plates (FGM) loaded by sinusoidally varying point load subjected to the arbitrary boundary condition is carried out. The governing differential equations for thin functionally graded plates (FGM) are derived using classical plate theory (CPT) and Rayleigh integral using the elemental radiator approach. Four cases, segregated on power-law index k=0,1,5,10, are studied. A novel approach is illustrated to compute sound fields of vibrating FGM plates using the physical neutral surface with an elemental radiator approach. The material properties of the FGM plate for all cases are calculated considering the power law indexes. An in-house MATLAB code is written to compute the natural frequencies, normal surface velocities, and sound radiation fields are analytically calculated using semi-analytical formulation. Ansys is used to validate the computed sound power level. The parametric effects of the power law index, modulus ratios, different constituent of FGM plates, boundary conditions, damping loss factor on the sound power level, and radiation efficiency is illustrated. This work is the benchmark approach that clearly explains how to calculate acoustic fields using a solid layered FGM model in ANSYS ACT. It shows that it is possible to asymptotically stabilize the structure by controlling the intermittent layers' stiffness. It is found that sound fields radiated by the elemental radiators approach in MATLAB, ANSYS and literatures are in good agreement. The main novelty of this research is that the FGM plate is analyzed in the low-frequency range, where the stiffness-controlled region governs the whole analysis. It is concluded that a clamped mono-ceramic FGM plate radiates a lesser sound power level and higher radiation efficiency than a mono-metallic or metal-rich FGM plate due to higher stiffness. It is found that change in damping loss factor does not affect the same constituents of FGM plates but has significant effects on the different constituents of FGM plates.

• 한국산학기술학회논문지
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• 제18권7호
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• pp.644-654
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• 2017

시장개방과 국제결혼의 증가로 인하여 한국사회는 점차 다문화사회로 진입하고 있다. 교육부는 다문화학생 교육 선진화 방안을 발표하여, 다문화학생에 대한 교육을 강화하고 있으며, 전체 학생을 대상으로 다문화이해교육을 실시하고 있다. 본 연구의 목적은 초등학교를 중심으로 다문화이해교육의 실제를 파악하고 향후 방향을 제시하는 것이다. 이를 위해 다문화이해교육 강사들이 학교 현장에서 다문화이해교육을 어떻게 진행하고 있는지 고찰하고 다문화 교육과정의 개념적 모형에 비추어 그들의 교수목표와 교육내용이 다문화적 가치를 잘 전달하고 있는지 살펴보았다. 연구방법은 4명의 다문화이해교육 강사를 연구 참여자로 섭외하고 사전인터뷰, 수업자료 검토, 수업참관 및 수업참관 후 사후 인터뷰를 실시하였으며, 이 연구과정에서 수집된 자료를 분석하여 주요 주제를 도출하였다. 연구 참여자들은 모두 초등학생을 대상으로 자신(배우자)의 출신국 문화를 소개하였으며, 수업은 전통복식, 음식 등 풍습위주의 외형적인 문화에 초점이 맞춰져 있었다. 다문화이해교육은 대상 학생 및 문화의 측면에서 다양성을 고려할 필요가 있으며, 2차시 분량의 일회성 수업으로 세계적 상황에 대한 공감능력 및 사회적 행위능력을 배양하기 다소 어려웠으며, 교과내용과 연계하여 융합교육과정으로 발전시키려는 노력이 필요하다.