• Journal of the Korean Wood Science and Technology
• /
• v.43 no.4
• /
• pp.456-462
• /
• 2015

365 pieces of domestic $38{\times}140{\times}3600mm$ Red pine structural lumber were machine graded conforming to a softwood structural lumber standard (KS F 3020). The allowable bending stresses calculated for each grade were compared with the values currently tabulated in the standard. Four calculation methods for lower $5^{th}$ percentile bending stress were non-parametric estimation with 75% confidence level, 2-parameter and 3-parameter Weibull distribution fit, and bending modulus of rupture (MOR)-modulus of elasticity (MOE) regression based method. Only the data set of Grades E8, E9, and E10 were statistically eligible for the $5^{th}$ percentile calculation. The MOR-MOE regression based method only was able to estimate the lower $5^{th}$ percentile values theoretically for the full range of grades. The results showed that all allowable bending stresses calculated were lower than the design values tabulated in the standard. This implies that the current machine grading system has the pitfall of structural safety. Improvement in current machine grading system could be achieved by introducing the bending strength and stiffness combination grade system.

• Ecology and Resilient Infrastructure
• /
• v.2 no.1
• /
• pp.80-92
• /
• 2015

Some of alien plants, which were introduced from foreign countries, have caused problems in Korea. Invasion of these alien plants in the ecosystem threatens the habitat of endemic species, reducing biodiversity, and causing a disturbance in the ecological system. In urbanized areas of campus universities, a diverse range of organisms were found and a comparison between the sites, near roads or housing sites were made because the campuses provided a large biotope. Although the campus had been exposed to interferences like gardening, it was also a place for most organisms to live in an active floating population due to free access. This research investigated the flora of alien plants that appeared in Beakseok University, Sangmyung University, Hoseo University and Dankook University, and relationship between the distribution of alien plants and the campus and green areas and distance from the highway. The total number of plant species and naturalized species found in the four universities was 189 and 43 species. Those of Dankook University were 136 and 35 species, Hoseo 108 and 25 species, Sangmyung 103 and 31 species, and Baekseok 97 and 26 species, respectively. The abundance of natural plants for each respective university tended to be higher as it became closer to the highway. Also, the closer the walking distance to the university, the greater the tendency for the degree of similarity to be higher. As a result, we may conclude that the distribution of alien plants and anthropogenic activities may be closely related.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.5
• /
• pp.109-115
• /
• 2016

A demand of high bearing capacity of piles to resist heavy static loads has been increased. For this reason, the utilization of large diameter PHC piles including a range from 700 mm to 1,200 mm have been increased and applied to the construction sites in Korea recently. In this study, in order to increase the flexural strength capacity of the PHC pile, the large diameter composite PHC pile reinforced by in-filled concrete and reinforcement was developed and manufactured. All the specimens were tested under four-point bending setup and displacement control. From the strain behavior of transverse bar, it was found that the presence of transverse bar was effective against crack propagation and controlling crack width as well as prevented the web shear cracks. The flexural strength and mid-span deflection of LICPT specimens were increased by a maximum of 1.08 times and 1.19 times compared to the LICP specimens. This results indicated that the installed transverse bar is in an advantageous ductility performance of the PHC piles. A conventional layered sectional analysis for the pile specimens was performed to investigate the flexural strength according to the each used material. The calculated bending moment of conventional PHC pile and composite PHC pile, which was determined by P-M interaction curve, showed a safety factor 1.13 and 1.16 compared to the test results.

• Journal of Korean Society for Geospatial Information Science
• /
• v.23 no.1
• /
• pp.3-14
• /
• 2015

As buildings in the downtown area, such as the complex building connected to the skyscraper and the underground facility, have become large and complex, the range of target domain of the space information service is rapidly expanding to the interior space; it is considered that this change will create various demands of service such as the indoor geospatial information base safety, the management of facility, and the interior navigation in the future, along with spread of mobile devices and development of IT technology. As for the indoor geospatial information, however, there is no certification standard of the established indoor geospatial information data quality, so preparing the certification standard is urgent. Thus, this study reviewed foreign and domestic research cases and prepared measures for quality verification of the indoor geospatial information to conduct a verification test of the Yeongdeungpo Station indoor geospatial information, established in 2014. As a result, through the verification test of the method and standard of the indoor geospatial information quality certification suggested by this research, it was identified that the uniform and higher quality data could be classified, and the types of error high frequently occurring could be investigated. These results are expected to be utilized as the basic data for establishing quality certification system for the indoor geospatial information in the future.

• Analytical Science and Technology
• /
• v.30 no.5
• /
• pp.295-302
• /
• 2017

This study presents a method validation for extraction and quantitative analysis of levulinic acid in soy sacues using high performance liquid chromatograph-photodiode array detector (HPLC-PDA). The levulinic acid in samples were extracted with distilled water, and then purified with C18 Sep-Pak cartridge. The calibration curves showed good linearity (R > 0.999) in a relatively wide concentration range ($2.5-400{\mu}g/mL$). Mean recoveries and relative standard deviation (RSD) of levulinic acid spiked in soy sauce samples at different spiking levels ($2.5-400{\mu}g/mL$; 6 point). Recoveries were 87.58-97.26 % with RSD less than 15 %, and limit of detection (LOD) and limit of quantification (LOQ) were 0.64 and $1.64{\mu}g/mL$, respectively. According to monitoring result with the established method, levulinic acid was found in 43 of 59 domestic commercial soy sauces, soy sauce based sauces and seasoned meats. The contamination levels were 0.44-1.23 mg/mL for soy sauces, 0.03-0.83 mg/mL for soy sauce based sauces and 8.43-38.94 mg/mL for seasoned meats. The results indicated to be rapidly and accurately qualifying levulinic acid and can be used as a suitable quality control method for soy sauce and soy sauce related commodities.

• Ecology and Resilient Infrastructure
• /
• v.6 no.4
• /
• pp.304-313
• /
• 2019

Biopolymer based on microbial β-glucan and xanthan gum is effective for vegetation and has a function of enhancing soil strength, which can be used as soil reinforcement and stabilization materials in river embankment. The purpose of this study is to verify the vegetation effect of the surface of levee by biopolymer with seed spraying method. Mixed soils with biopolymer were used to cover the surface of embankments. The strength is higher in biopolymer-treated soil and xanthan gum based biopolymer has advantage for quality control in field scale. In addition, the vegetation of F. arundinacea and L. perenne showed various reactions with types of biopolymers. Biopolymer has a positive effect on the vegetation of them. In contrast, root growth tended to decrease in biopolymer-treated soils. The results indicate that root growth is slow down due to increasing ability to retain water in biopolymer-treated soil. In order to apply biopolymer to river embankment, it is necessary to examine the effects of biopolymers on a wide range of plant species in river embankment.

• Science of Emotion and Sensibility
• /
• v.20 no.1
• /
• pp.3-16
• /
• 2017

With the development and proliferation of three-dimensional(3D) printers, consumers in modern society can now print products of what they want three-dimensionally at home. However, consumers themselves would have to produce digital design maps that are compatible with 3D printers and to set up the optimum printing quality and temperature, as well as to pay for maintenance and repair of 3D printers and to respond to any possible lawsuits related to intellectual property right about designs in order to make possible consumer-tailored manufacturing through 3D printing. However, in reality, since it is very difficult for consumers to respond to these issues, it is necessary to develop services that perform 3D printing on behalf of consumers in the desired direction. Motivated by this objective, this study investigated user experiences on Shapeways(www.shapeways.com), which is a global online 3D printing product and sales companies, from many viewpoints in order to obtain insight into 3D printing services and modes which were preferred by consumers. The study result showed that quantitative evaluations on usability, search process, price adequacy, re-visit intention, diversity of design, and satisfaction of design was scored low overall. Furthermore, this study acquired insight about consumer-tailored 3D printing services through constructive suggestions on multi-language support, openness of manufacturing process, simultaneous operation of online and offline sites, design-oriented consumer-tailored manufacturing service, services that ensure delivery safety and product durability, and surface finishing services. This study is expected to provide a wide range of opinions not only on 3D printing service platform development but also on related industry and research.

• Applied Chemistry for Engineering
• /
• v.5 no.4
• /
• pp.573-579
• /
• 1994

1-O-oleoyl glycerol, 2-O-oleoyl myo-inositol and methyl 2-O-oleoyl-${\alpha}$-D-glucopyranoside were used as surfactants in this study. The solution properties and solubilization process of those nonionic surfactants were examined by the phase equilibria. As a result of this study, we have found that phase behavior of two component systems of surfactants/$H_2O$/cyclohexane depends on temperature respectively. The three phase regions of three component systems appeared in the temperature range of $27^{\circ}C{\sim}32^{\circ}C$, $36^{\circ}C{\sim}45^{\circ}C$ and $38^{\circ}C{\sim}52^{\circ}C$ and solubilization of water and oil was high in those three phase ranged As the temperature was varied in the two component systems, liquid crystals of hexagonal were observed to in the case of 1-O-oleoyl glycerol, and liquid crystal of lamella types were observed in the case of 2-O-oleoyl myo-inositol and methyl 2-O-oleoyl-${\alpha}$-D-glucopyranoside.

• Korean Journal of Environmental Agriculture
• /
• v.20 no.3
• /
• pp.169-174
• /
• 2001

This study was conducted to compare and evaluate the heavy metal contents of agricultural products in Korea and to compare with relevant international criteria such as the Average Daily Intake(ADI) and the Provisional Tolerable Weekly Intake(PTWI) proposed by the joint FAO/WHO Codex Committee on additives and contaminant. Contents of heavy metal in cereals, pulses, potatoes, vegetables and fruits were in the range of $0.010{\sim}0.073$ for Cd, $0.40{\sim}6.45$ for Cu, $0.083{\sim}0.698$ for Pb, $2.45{\sim}16.30$ for Zn, $0.171{\sim}1.378$ for Ni, $0.023{\sim}0.233$ for Cr and $0.026{\sim}0.070$ mg/kg(F.W.) for As. Heavy metal contents of cereals, pulses, potatoes, vegetables and fruits were with natural content levels proposed by FAO/WHO and were similar to value monitored in other countries. Also, average intake of heavy metal from agricultural products was lower than the ADI and PTWI by the joint FAO/WHO Codex Committee on Additives and Contaminants. Therefore, none of the cereals, pulses, potatoes, vegetables and fruits evaluated showed accumulation of such heavy metal high enough to cause health problems to human.

• Korean Journal of Acupuncture
• /
• v.20 no.3
• /
• pp.35-47
• /
• 2003

Objective : The purpose of this study was to investigate the significance of the Oriental medical treatment using He-Ne laser with low energy intravascular Laser Irradiation of Blood(ILIB) through the superficial venules. Methods : The investigation of details connected with the superficial venules in the literature is performed. The investigation of details connected with the pricking blood techniques through the superficial venules in the literature is performed. The classification of the pricking blood techniques through the superficial venules by the blood-letting puncture methods in the literature is performed. The arrangement of domestic clinical treatises on the effectiveness of medical treatment using He-Ne laser with low energy ILIB through the superficial venules is performed. The consideration on the methodology for the improvement of the clinical effectiveness of He-Ne laser with low energy ILIB through superficial venules is performed. Results and Conclusions : The superficial venules are small arteries, veins and capillaries in the superficial region of the human body. In the pricking blood techniques, there are the blood-letting puncture using the implement of acupuncture to the Jing points, Extra points and superficial blood vessels and the acupuncture using the Hirudo. The methods of the blood-letting puncture are classified into the venous blood-letting puncture, the pricking , the picking out white fiber-like substances from the subcutaneous tissue, the cluster needling, the scattered needling, the blood-letting puncture of the tready collateral branch of the large channel and the blood-letting puncture of skin. The He-Ne laser with low energy ILIB through the superficial venules belongs to the Oriental medical treatment as the method of the blood-letting puncture in the vein of cubital fossa. The He-Ne laser with low energy ILIB has an effect on hyperfibrinogenemia, hyperlipidemia, speech and motor dysfunction in the case of cerebral infarction, headache, dizziness, pain and numbness. It is considered that fundamental research on the biological change of the human body, the experimental animal and the unicellular animal, and research on the effectiveness and the safety, and the development of He-Ne laser with low energy ILIB of an effective wavelength range are necessary.