Korean Standards Research Articles

Use of Pine (Pinus densiflora) Pollen Cones as an Environmentally Friendly Sound-Absorbing Material

This study examined the utility of pine (Pinus densiflora) pollen cones as an environmentally friendly material with sound-absorbing properties. Pine pollen cone samples with widths of 0.8–1.2 cm and lengths of 3.5–4.5 cm were prepared. After filling impedance tubes to heights of 6, 8, 10, or 12 cm with the pine pollen cones, the sound absorption coefficient of the pine pollen cones was investigated. The peak sound absorption frequency of the samples with a thickness of 6 cm was reached at 1,512 Hz; however, this value shifted to 740 Hz in samples with a thickness of 12 cm. Therefore, the sound-absorbing performance of pine pollen cones at low frequencies improved as the material thickness increased. According to KS F 3503 (Korean Standards Association), the sound absorption grade of pine pollen cones ranges from 0.3 to 0.5 M, depending on the material thickness of the pine pollen cones. In conclusion, the pine pollen cones demonstrated good sound absorption properties. They, thus, may be considered an environmentally friendly sound-absorbing material.

국내 신선 농산물 포장용 골판지 상자의 이용 실태 및 물리적 특성 연구 : 경북 경산 소재 지역 중심으로

In this study, forty corrugated fiberboard (CF) boxes for fresh produce were collected from farms located in Gyeongsan city and evaluated its characterizations and physical properties according to Korean Standard (KS). The basis weight, flute, and paperboard combination were determined for the characterizations of CF boxes. The measured basis weights of all samples were within the tolerance limit referred to KS and the flutes were B/F, EB/F, and AB/F flute, respectively. The bursting strength (BS), edgewise crush resistance (ECR), and compression strength (CS) were tested to evaluate the physical properties. There are four single-walled (SW) CF boxes showed BS and ECR higher than 638 kPa and 3.30 kN/m, respectively. One SW CF boxes showed BS and ECR higher than 785 kPa and 3.43 kN/m, respectively. In case of double-walled (DW) CF boxes, sixteen CF boxes showed BS and ECR higher than 785 kPa, 4.96 kN/m (AB flute), or 4.90 (EB flute), respectively. The other nineteen CF boxes showed BS and ECR higher than 981 kPa, 5.29 kN/m (AB flute), or 5.20 (EB flute), respectively. All the CF boxes except two samples showed the acceptable compression strength in reference to the guideline of KS.

규격분석 및 AHP를 활용한 고령자와 장애인용 2인승 역 삼륜 자전거 안전성 연구

Objective:The aim of this study is to propose a safety design guideline for a tricycle tandem for two persons for the elderly and persons with disability through standard survey and dynamics simulation.<BR>Background: In this recent, the issue of leisure and quality of life for the elderly has become more important due to the aging population. It has been found that the elderly and persons with disability prefer to ride a tricycle outdoors as a leisure activity to enjoy with family and friends. Most of the tricycles they can enjoy together are imported products and have not been developed in consideration of the domestic use environment, so research on their safety is needed.<BR>Method: In this study, in order to propose a safety design guideline for a tricycle tandem for two persons, the Korean standard (KS) was investigated to derive, and 10 major safety design factors were derived from the four related standards. And the importance of safety design factors was analyzed using the AHP (Analytic Hierarchy Process) method. In addition to the dynamics simulation of steering, safety design guidelines for 10 major safety design factors have been proposed.<BR>Results: In the results of the importance analysis (AHP) between the 10 safety design factors derived through the survey of existing standards,

Comparison of the Performance of the Steel Fiber Shotcrete and Cast Concrete considering Accelerator Types and Core Sizes from a Tunnel Site

Shotcrete is considered a substantial long-term product providing a sheltered working environment for tunneling engineering. However, multi-functional problems occur due to the sprayed concrete construction method. Moreover, the performance of the shotcrete placement into the wall of the tunnel is challenging to verify. Currently, accelerators are used in highway tunnels for improving the overall performance of shotcrete. This study evaluated the tunnel shotcrete performance for cement mineral, aluminate, and alkali-free accelerators, as well as steel fiber, which is the main constituent of shotcrete. The workability of concrete and shotcrete in situ has been measured for these combinations. Using 1-month samples, shotcrete was evaluated by means of accelerating agent, compressive strength, core compressive strength, flexural strength, and flexural toughness. In particular, 37 kg and 40 kg of steel fiber were included into the cement and aluminate mix and the alkali-free mix, respectively. Changes in strength and flexural performance of shotcrete were studied under Korean standard. Thus, concrete cylindrical molds were manufactured for the compressive strength test. After 28 days of curing, concrete and shotcrete test panels were manufactured for core compressive strength tests on cylindrical molds with diameters of 100 mm, 75 mm, and 55 mm. Furthermore, beam samples were produced for flexural strength and toughness tests to measure the shotcrete performance. Air void test and steel fiber remaining percentage after shooting were performed to ensure the performance image analysis. Alkali-free incorporated with steel fiber is the best combination for tunnel shotcrete premised on compressive strength, core compressive strength, flexural strength, and toughness test results, along with environmental and worker safety. Finally, the tunnel shotcrete performance was evaluated by regulating and improving the accelerator type with the steel fiber for shotcrete.

Long-term Assessment of Ozone Nonattainment Changes in South Korea Compared to US, and EU Ozone Guidelines

We conducted spatiotemporal assessments of ozone in South Korea from 1990–2020 to evaluate trends and compare changes in compliance based on South Korean, US, and EU standards. Observational data from nationwide air-quality monitoring stations were collected and converted to the maximum daily 8 hr ozone average (MDA8O3). Seasonal ozone variations displayed an overall increase across most of South Korea and a noticeably high rate of 0.86 ppbv/yr in Seoul, with an even higher rate 1.2 ppbv/yr for the fourth-highest MDA8O3. Recent air-quality regulations to reduce NOx emissions have been estimated to weaken NO titration effects, leading to higher ozone levels for VOC-limited urban areas in South Korea while decreasing ozone concentrations elsewhere. In recent years, nearly all monitoring stations have exceeded the South Korean MDA8O3 standard, leading to debate regarding the adequacy of current standards for monitoring changes in nonattainment. Comparison with EU and US standards showed that implementing these could significantly lower nonattainment events due to the easing of target threshold values by either percentile or concentration values. Relative distances in nonattainment percentages between South Korean and other standards indicated that the EU ozone guideline was most suitable for tracing recent ozone changes not apparent when using the South Korean or US standards.

Application of Waste Plastic Films in Road Infrastructure and Construction

Recycling waste synthetic resins, including rigid and film plastics, is a pressing issue worldwide due to the issues associated with waste treatment. Using products originating only from plastic wastes could be a promising way to improve the waste recycling rate and address plastic consumption. This study presents the applications of waste plastic films (WPFs) in urban infrastructure and construction materials, especially bearing loads. WPF-recycled products (WPF-RPs) were evaluated for mechanical properties, including strength (compressive and tensile), thermal expansion coefficient, accelerated weathering, dynamic stability, and environmental aspects, such as the presence of hazardous substances. Subsequent tests confirmed moderate strength, good weathering stability against solar irradiation, and superior road pavement vehicle load through wheel-tracking tests compared with the standards for asphalt. Additionally, hazardous substances were mostly not detected or were under permissible limits in the composition and leachate contents of WPF-RPs. After using temporary pavement blocks (TPBs) from WPFs at a field site for one month, we conducted slip resistance tests which gave a result of ~33 British pendulum number, indicating the possible application of WPF-RPs in low-speed driving sections, according to the Korean standards of the Ministry of Land, Infrastructure and Transport. Moreover, it was confirmed that fastening structures installed between the TPBs can improve backfilling and compaction defects. This practical research highlights the possible applications of products produced from WPFs for infrastructure development, such as filling materials for burial pipes or tubes; however, these potential aspects should be tested further.

High-level dietary crude protein decreased backfat thickness and increased carcass yield score in finishing Hanwoo beef cattle (Bos taurus coreanae).

Recently, a high level of dietary crude protein (CP) has become of interest as a possible practice to improve the carcass quality of beef cattle, and its level has been increasing in the field. However, there is little scientific evidence that supports this. This study was conducted to test whether a high dietary CP level would improve growth performance, body metabolism, and carcass traits in Hanwoo beef cattle. A total of 32 Hanwoo finishing beef cattle (18 multiparous cows, six heifers, and eight steers) participated in a 12-weeks feeding trial. Two kinds of total mixed rations were prepared to contain two different CP; 156 g/kg for the control (CON) and 173 g/kg of CP for the treatment (HCP), while maintaining a similar level of metabolizable energy. The experiment was ended when more than half of the steers reached the target body weight (730 kg). Blood was collected at the end of the experiment. After harvesting, the carcass trait was evaluated at the slaughterhouse according to Korean standards. The carcass yield score and grade were also calculated based on revised criteria. Overall, dry matter intake, average daily gain, blood metabolites concentration, and the carcass traits, except for backfat thickness and the yield score, did not differ between the treatments. The HCP had lower backfat thickness than those of CON. There was no difference in the carcass yield grade, but the yield score was higher in the HCP treatment. According to the newly revised carcass grading criteria, both yield score and grade were higher in HCP than in CON. Increasing CP supply decreased the carcass’s backfat thickness without altering growth performance and body metabolism, resulting in improved yield score and grade. Therefore, feeding a high CP diet may be beneficial in the farm income, although it may also increase feed cost and nitrogen excretion to the environment.

Environmental Assessment of Recycling (EAoR) for Safe Recycling of Steelmaking Slag in the Republic of Korea: Applications, Leaching Test, and Toxicity

Steel slag is a major waste product of the steelmaking process. Owing to its chemical composition, it can be reused as a raw material in steel mills and a substitute for aggregates in engineering. In 2016, the Republic of Korea (ROK) introduced the Environmental Assessment of Recycling (EAoR) system for the safe recycling of waste products, which divides recycling methods into either matrix contact or non-matrix contact types; numerous challenges have been raised regarding weaknesses in the matrix contact type. Consequently, the standards for matrix contact recycling of slag (inorganic waste) have become stricter, and the recycling applications have also become more diverse. This study investigates the treatment, recycling, and management of steel slag in the ROK. In 2019, the annual generation of slag in the ROK exceeded 23.03 million tons with a recycling rate of 98.3%, showing a high level of recycling, compared with that of the United States (81.3%), the European Union (87%), Australia (100%), and Japan (98.4%). However, a comparative analysis of overseas slag recycling systems and recycling standards found that the recycling applications and recycling standards of slag in the ROK were somewhat stricter than those in the European Union and the United States. Furthermore, an investigation comparing the applications of recycled slag in different countries showed that the ROK could expand its applications of recycled slag. The limitation of the EAoR system was that the excluding products, environmentally certified from Korean Standards in the EAoR regulations, might be attributing to environmental pollution. The leaching and toxicity tests for recycling application of steelmaking slag were evaluated and showed no significant negative effects. Lastly, there is an urgent need for environmental standards relating to slag that can be recycled as a product, and the recycling and environmental label certification for products should also be amended. In addition, the applications of steelmaking slag were necessary to partially extend according to the hazardous characteristics.

시뮬레이션을 통한 어린이집의 환기시스템 및 공기청정기 설치에 따른 미세먼지 저감 효과 분석

The purpose of this study is to identify an effective method among solutions such as ventilation system and air cleaning unit operation as measures to reduce particulate matters in a child care center. Results are as follows. When children are active in the child-care room, the indoor PM2.5 concentration is increased up to 5.5 times compared to the Korean standard of 35 ㎍/㎥. PM2.5 concentrations in all child-care rooms exceeded the standard. In such situations, if the ventilation system was operated, indoor PM2.5 concentration could be maintained below the standard value except for child-care room 1 on the 1st floor. In case of an air cleaning unit with a capacity of CADR 57 ㎡, a filter efficiency of 80%, and an operation rate of 95%, it did not satisfy the standard value of indoor PM2.5 concentration for all child-care rooms. However, if the capacity of air cleaning unit was increased to CADR 87 ㎡ under the condition of 95% filter efficiency, indoor PM2.5 concentrations in all child-care rooms could be maintained below the standard value. Thus, if an air cleaning unit with a capacity of CADR 57 ㎡ and 95% filter efficiency is operated in combination with a ventilation system, indoor PM2.5 concentrations in child-care rooms can be maintained below the standard value.

A COMPARATIVE STUDY ON THE PHYSICAL AND MECHANICAL PROPERTIES OF DAHURIAN LARCH AND JAPANESE LARCH GROWN IN KOREA

To compare the wood quality of Dahurian larch and Japanese larch growing in Korea, the physical and mechanical properties were examined using the Korean standards. The proportion of heartwood was 82% and 72% in Dahurian and Japanese larch, respectively. The percentage of latewood was 42% in Dahurian larch and 35% in Japanese larch. The growth ring width of Dahurian larch was narrower than that of Japanese larch. Dahurian larch showed about 20% higher green moisture content compare to Japanese larch wood. Density and shrinkage of Dahurian larch were higher than Japanese larch. Axial compression strength, young`s modulus in compression, and shearing strength in heartwood of Dahurian larch were 11 MPa, 686 MPa, and 2.3 MPa, respectively, showing higher value than Japanese larch. The hardness was in the range of 13.8–38.7 MPa in Dahurian larch and 17.7–48.4 MPa in Japanese larch. The compression strength parallel to the grain and shearing strength in both species were significantly correlated with oven-dried density. Besides, the hardness in Dahurian larch was significantly correlated with latewood percentage and oven-dried density. In conclusion, the differences in the properties of both species were revealed and the results can be used for quality indices of both wood species.

Incorporation of copper slag in cement brick production as a radiation shielding material

This study explored the influence of using copper slag as an alternative sand for producing cement mortar bricks and its effect on γ-ray attenuation property, strength, and consistency of mortar. The linear attenuation coefficients and mass attenuation coefficients were experimentally determined for mortar mixtures using the 60Co and 137Cs gamma-ray source, and, using the Phy-X program, attenuation parameters were theoretically calculated in 1 keV–100 GeV. Sample bricks with added copper slag were produced and tested. In the results, the added copper slag was greatly beneficial for increasing the flowability and strength of mortar, and, given all the results of attenuation parameters, the use of copper slag as aggregates was notably advantageous compared to silica sands for gamma-ray attenuation mainly due to the high Fe quantity in copper slag. The trial brick specimens using 100 wt% copper slag replacement for sand not only satisfied all requirements of cement brick in the Korean standard (KS) F 4004, but also the TCLP regulation.

Masked Implementation of Format Preserving Encryption on Low-End AVR Microcontrollers and High-End ARM Processors

Format-Preserving Encryption (FPE) for Internet of Things (IoT) enables the data encryption while preserving the format and length of original data. With these advantages, FPE can be utilized in many IoT applications. However, FPE requires complicated computations and these are high overheads on IoT embedded devices. In this paper, we proposed an efficient implementation of Format-preserving Encryption Algorithm (FEA), which is the Korean standard of FPE, and the first-order masked implementation of FEA on both low-end (i.e., AVR microcontroller) and high-end (i.e., ARM processor) IoT devices. Firstly, we show the vulnerability of FEA when it comes to the Correlation Power Analysis (CPA) approach. Afterward, we propose an efficient implementation method and the masking technique for both low-end IoT device and high-end IoT device. The proposed method is secure against power analysis attacks but the performance degradation of masked measure is only 2.53∼3.77% than the naïve FEA implementation.

유산균 첨가가 양념젓갈의 보존성에 미치는 영향

The salted fish or seasoned-fermented shellfish, jeotgal, is traditionally prepared for a long time and popular as a side dish for Koreans. However, high salt content is known as a key factor to hinder its sales in current health-conscious society. Based on the guideline of Korean Standards, the fermented or seasoned fish products including salted-seasoned squids should contain fish as a raw material more than 75% in the products. An immunostimulatory LAB strain, which was characterized by this research group, was deliberately added into both the squid and the oyster samples for examining quality change during storage. 300 g of each sample was divided into two storage conditions: 5˚C and room temperature, 20˚C. As a result, all the samples with LAB tend to increase in viable cell counts under room temperature preservation, especially in the fermented oyster samples with LAB increase 100 times after 2 weeks storage. On the other hand, it was noted that general bacterial counts maintain almost constant in all the samples irrespective to addition of LAB. Judging from the bacterial examination, the addition of LAB in the squid and the fermented oyster samples neither affects the changes of LAB and general bacterial counts nor inhibits the bacterial growth in this experimental settings. It is not expected the increase in LAB added during the usual shelf life of the commercial products. Compared to non-LAB samples, overall acceptance was significantly better for the samples added LAB. In conclusion, this experiment suggests that addition of LAB is strongly recommended to develop low-salt fermented fish and shellfish products of higher sensory qualities.

Review and Improvement Direction of the Riprap Design Standard for Fill Dams in Korea

Since domestic reservoirs are mainly soil-fill dams, slope protection measures are necessary to prevent erosion, weathering, and wave-induced loss of soil, and riprap is the most common slope protection method. Although design standards for riprap at fill dams are provided in National Design Standard of Korea, they use out-of-date criteria based largely on overseas standards that may not be applicable to the Korean context. This study aimed to identify problems with the current design standards by comparing them with overseas standards, and to suggest directions for improving Korean standards through investigations of existing embankments. The review found that domestic design standards restrict the quality and maximum particle size of stone used for riprap. Much of the design criteria are based on past surveys of the performance record for fill dams conducted by the US Army Corps of Engineers. So this can be unsuitable for changes in modern technology and environmental conditions in Korea. More recent design trends suggest riprap size using an experimental formula, which is numerically different from the data presented in domestic design standards, and this may lead to unstable and uneconomic dams. In addition, various factors such as the shape, weight, and gradation of the riprap can also have a strong influence on riprap stability. The results of the survey show that current condition of the riprap protection is different from the domestic design standard, but it is judged that the stability is satisfied with the overseas design standards. In the field survey, 12 sites were selected in consideration of regional distribution. The results of the survey show that current condition of the riprap protection is different from the domestic design standard, but it is judged that the stability is satisfied with the overseas design standards.

Performance Evaluation of Rigid Braced Indirect Suspended Ceiling with Steel Panels

In Korea, the earthquakes in Gyeongju (2016) and Pohang (2017) have led to increased interest in the seismic design of nonstructural elements. Among these, the suspended ceiling can cause personal injury and property damage. In addition, most suspended ceilings that are used in Korea neither have seismic design details nor meet the current seismic design standards. There are two seismic design methods for suspended ceilings using a perimeter clip and a brace. In the United States and Japan, seismic design of ceilings is typically used, but the concepts of applying and installing braces are different. This is because the typical ceiling systems are different in the United States and Japan. In this study, a brace-applied ceiling system that is suitable for a suspended ceiling with a steel panel was applied in the indirect suspended ceiling mainly used in Korea. In addition, the seismic performance was verified through a shaking table test. All the specimens were applied with anti-falling clips that are designed to prevent the panels from falling, and they satisfy KDS 41 17 00, which is a Korean seismic design life safety standard. Without considering these factors, the performance level is lower than a nonseismic designed ceiling, which is not properly designed or constructed.

Beauty and Celebrity: Korean Entertainment and Its Impacts on Female Indonesian Viewers’ Consumption Intentions

The Korean entertainment industry’s popularity and global reach has prompted private companies and destination management organizations to place Korean products and position Korea as a destination to international viewers. Korean celebrities have also been found to form positively perceived Korean beauty standards, consequently serving as an antecedent of Korean beauty product awareness and perceived beauty product quality among international audiences. Although previous studies have found that audience involvement with entertainment mediums has positively impacted product purchase and visitation, a comprehensive investigation of the audience involvement’s multi-dimensionality has yet to be conducted, specifically, on the distinction between Korean entertainment (movies, TV dramas, TV shows, etc.) involvement and celebrity worship. The present study attempts to fill the research gap by comprehensively examining the role of audience involvement with Korean entertainment, celebrity worship, brand awareness, and perceived Korean beauty product quality on product purchase intentions as well as intentions to visit Korea. A total of 327 female Indonesian Korean entertainment audiences then validated the proposed conceptual framework. The structural equation modeling results found emotional involvement, referential reflection, and entertainment-driven celebrity worshipping tendencies to be significant antecedents of Korean beauty product purchase and Korea visit intentions.

Maintaining active safety performance through appropriate vehicle bumper refinishing: Case study for Korean minor damage repair standards

The Korean government has established “minor damage repair standards” that require repair without replacement when vehicle bumpers can be repaired to reduce plastic bumper waste. However, when blind spot detection and lane change assist systems, active safety systems, are installed, there is a controversy over whether the standards can be applied to restore the minor damage bumper covers because the short-range radar sensor for them is located inside each corner of the rear bumper. Therefore, it is necessary to identify the difference between original and repair conditions to confirm the repair methods that can meet the government’s standards while maintaining the safety performance of the systems. The experiments were designed two sectors, most vehicle bumper cover repair methods were produced as test specimens which are used for static tests to compare with the new vehicle state, and based on the results, specimens needed field confirmation were prepared and dynamic tests were conducted. The microscopic performance difference of the safety systems according to the refinishing was determined by analyzing the dynamic test results using null-hypothesis significance testing and analysis of variance methods. The results of the tests showed that applying a filler to form the bumper surface does not cause performance problems if the radar signal transmission area of 10 m2is avoided. In the case of paintwork on the radar signal area, two or three layers of paint did not show any difference from the manufacturer’s bumper, therefore paint layer scratches can be refinished up to twice. However, if metal-colored paint layers are three as a result of paintwork twice, the maximum detection angle performance is adversely affected. Through this study, new experimental methods were suggested for identifying the safety performance of advanced driver assistance systems when various repair methods are applied to the plastic bumper cover.

Thermo-Chemical Treatment for Carcass Disposal and the Application of Treated Carcass as Compost

A mechanized thermo-chemical treatment system was developed to treat the undecomposed carcass and remediate livestock burial sites. Animal carcasses were thus processed via crushing, mixing, and treatment with quicklime treatment, heat treatment (200–500 °C), and mixing with sawdust. The machinery was applied to two sites where 16,000 chickens and 418 pigs had previously been buried in fiber-reinforced plastic storage bins. No dioxins were detected in the gas discharged during processing, and the concentration of total volatile organic compound, toluene, ethylbenzene, xylene, and styrene were 430.3, 139.0, 18.3, 21.4, and 10.4 μg/m3, respectively, which were below the air pollutant emission standards issued by the Korean Ministry of Environment. Korean standards stipulating the use of treated carcasses as compost (C, N, and P content, heavy metal concentration, Escherichia coli, and Salmonella) were met, but the germination index value was less than 70, not satisfying the criteria. Plant height, leaf length, leaf width, and dry weight of lettuce grown in soil amended with treated carcass product were significantly lower than those grown in low nutrient soil due to the poor germination index of the treated carcass. These results indicate that a composting process is required before the use of the treated carcass as a fertilizer. The addition of zeolite retarded the elution of ammonia from the carcasses and its efficiency was about 87.9%. It is expected that the mechanized thermo-chemical treatment process developed in this study could replace other technologies for the remediation of livestock burial sites.

A Study on the Evaluation System of Korean Standards Commission

A Study on the Evaluation System of Korean Standards Commission

Effect of hot-water extraction on the hygroscopicity, shrinkage, and swelling of Paulownia tomentosa wood

Liquid water and water vapor absorption on each separate surface and all surfaces at once, as well as the oven-dry shrinkage before and after the hot-water extraction of the wood, were examined using Korean Standards. The extractives content was examined using American Society for Testing and Materials (ASTM) standards. The highest water absorption and moisture adsorption were found in the transverse sections of both unextracted and extracted wood samples. There was no change in the equilibrium moisture content (EMC) in the unextracted vs. extracted wood samples at a relative humidity (RH) of 75%. However, the EMC in the extracted sample was higher than that in the unextracted sample at a RH of 90%. Swelling per 1% moisture content remained unchanged in the radial direction before and after extraction, while it increased in the tangential direction. The linear and volumetric shrinkage, as well as the coefficient of anisotropy, considerably increased after extraction. There was no difference in the extractive content between sapwood and heartwood. In conclusion, it was confirmed that the extractives in wood considerably affect the hygroscopicity and shrinkage of Paulownia wood.