Chun-Won Kang

Bio: Chun-Won Kang is an academic researcher from Chonbuk National University. The author has contributed to research in topics: Materials science & Noise reduction coefficient. The author has an hindex of 8, co-authored 59 publications receiving 212 citations. Previous affiliations of Chun-Won Kang include Kyushu University.

Changes in gas permeability and pore structure of wood under heat treating temperature conditions

Abstract: In this study, changes in gas permeability and pore structure of wood are evaluated after heat treatment with temperatures ranging from 190 to 230 °C for 6 h for both hardwood (yellow poplar: Liriodendron tulipifera) and softwood (Korean red pine: Pinus densiflora). The purpose of this study is to investigate changes in pore size, content of three pore types (through pore, blind pore, and closed pore), as defined by IUPAC, and gas permeability by increasing heat treatment temperatures in hardwood and softwood using capillary flow porometry and gas pycnometry. As the heat treatment temperature increased, only through pore porosity increased, causing an increase in gas permeability.

An experimental study on change of gas permeability depending on pore structures in three species (hinoki, Douglas fir, and hemlock) of softwood

Abstract: The purpose of this study is to analyze the pore structure for the heartwood, intermediate wood, and sapwood sections in three species of softwood (hinoki, Douglas fir, and hemlock) and to investigate the correlation of gas permeability depending on pore structure. For this study, gas permeability and pore size were measured by capillary flow porometry, and classification of a novel method was performed to determine the type of pores (through pores, blind pores, and closed pores) based on International Union of Pure and Applied Chemistry (IUPAC). Gas permeability, through pore porosity, and pore size increased from heartwood to sapwood. The results of multiple regression analysis showed that through pore porosity, mean pore size, and bulk density were significant factors affecting gas permeability.

Sound absorption capability and mechanical properties of a composite rice hull and sawdust board

Abstract: Rice hull–sawdust composite boards were manufactured for sound-absorbing boards in construction. The manufacturing parameters were target density (400, 500, 600, and 700 kg/m3) and rice hull content as percent weight of rice hull/sawdust/phenol resin (10/80/10, 20/70/10, 30/60/10, and 40/50/10). Commercial gypsum board and fiberboard were also used as comparative sound-absorbing materials. The average modulus of rupture (MOR) of the board with a density of 700 kg/m3 and rice hull mixing ratio of 10% was 8.6 MPa, and that of the board with a 400 kg/m3 board density and a rice hull mixing ratio of 40% was 2.2 MPa. The MOR increased with increasing board density or decreasing rice hull mixing ratio. The sound absorption coefficients of some boards (400 kg/m3 and 10%, 500 kg/m3 and 30%, and 500 kg/m3 and 40%) were better than those of the commercial 11-mm-thick gypsum board. Thus, it is concluded that rice hull–sawdust composite boards may be implemented as sound-absorbing barriers in construction due to their high sound absorption coefficients.

Impact of community masking on COVID-19: A cluster-randomized trial in Bangladesh

Abstract: Persuading people to mask Even in places where it is obligatory, people tend to optimistically overstate their compliance for mask wearing. How then can we persuade more of the population at large to act for the greater good? Abaluck et al . undertook a large, cluster-randomized trial in Bangladesh involving hundreds of thousands of people (although mostly men) over a 2-month period. Colored masks of various construction were handed out free of charge, accompanied by a range of mask-wearing promotional activities inspired by marketing research. Using a grassroots network of volunteers to help conduct the study and gather data, the authors discovered that mask wearing averaged 13.3% in villages where no interventions took place but increased to 42.3% in villages where in-person interventions were introduced. Villages where in-person reinforcement of mask wearing occurred also showed a reduction in reporting COVID-like illness, particularly in high-risk individuals. —CA

Physical and mechanical properties of particleboard manufactured from wood, bamboo and rice husk

Abstract: In this work, the physical-mechanical properties of particleboards manufactured with wood (Eucalyptus grandis), bamboo (Bambusa vulgaris) and/or rice husk (Oryza sativa) particles, combined or not, were assessed. They were produced in the following proportions: 100% wood; 100% bamboo; 100% rice; 50% wood and 50% bamboo; 50% wood and 50% rice husk. In order to characterize the manufactured particleboards, their physical (density; moisture content; water absorption and thickness swelling) and mechanical properties (static bending; internal bonding and screw withdrawal) were assessed. The results indicated that the use of rice husk caused reduction in particleboard quality. Particleboards manufactured with bamboo showed better quality than those using rice husk as raw material. For most parameters, the particleboards manufactured exclusively with wood particles showed similar performance to bamboo and wood-bamboo particleboards.

Changes in gas permeability and pore structure of wood under heat treating temperature conditions

Abstract: In this study, changes in gas permeability and pore structure of wood are evaluated after heat treatment with temperatures ranging from 190 to 230 °C for 6 h for both hardwood (yellow poplar: Liriodendron tulipifera) and softwood (Korean red pine: Pinus densiflora). The purpose of this study is to investigate changes in pore size, content of three pore types (through pore, blind pore, and closed pore), as defined by IUPAC, and gas permeability by increasing heat treatment temperatures in hardwood and softwood using capillary flow porometry and gas pycnometry. As the heat treatment temperature increased, only through pore porosity increased, causing an increase in gas permeability.