• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.7 s.144
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• pp.1027-1036
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• 2005

Based on the correlation analysis result of preceding research, the biodegradabilities of cellulose fibers were closely related to the moisture regain of the samples, which reflects the hydrophilicity and internal structure of the fibers. In addition to this factor, it was expected that the biodegradation conditions influence the biodegradability of fibers. In this study, widely used cellulose fibers including cotton, rayon, and acetate were used. The biodegradabilities of cellulose fibers were measured by soilburial test, and then the degradation behaviors based on each condition were compared. Moreover, the effects of degradation conditions such as humidity of the soil were investigated. Changes in the internal structure of samples were also observed by X-ray analysis according to the soil burial time. It was shown that humidity of soil facilitated the degradation of cotton, rayon, and acetate fibers, showing higher degradation rate with higher humidity in soil. This effect was shown to be much greater in the fibers of high moisture regain such as cotton and rayon. In respect of microstructure change, crystallinities and their crystal size of fibers decreased remarkably in the soil of higher humidity. It was revealed that degradation of crystalline area was more dependent on the soil humidity than that of amorphous area.

• Journal of Environmental Science International
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• v.6 no.4
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• pp.379-384
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• 1997

The biodegradable characteristics of poly-$\beta$-hydroxybutyrate(PHB) film by fun맥 and soil burial are Investigated. As the results of the American Standards for Testing and Materials(ASTM) method, the you of Aspergillus niger was apparent on the PHB containing plate. This suggests that PHB was utilized as the sole carbon source by Aspergillus niger and ASTM method may have applications as measuring means of biome gradability of polyhydroxyalkanoic acid(PHA). PHB film was studied by monitoring the time-dependant changes in weight loss of PHB film under 30% and relative humidity 80 % during pot-test. As the results of pot-test, PHB film was decomposed about 87 % in 30 days by soul microorganisms. PHB film was more slowly degraded than PHB/HV film.

• Geomechanics and Engineering
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• v.8 no.2
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• pp.221-235
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• 2015

A series of laboratory model tests were conducted to investigate the effects of buried pipes location on the bearing capacity of strip footing in cohesionless soil. The variables examined in the testing program include relative density of the sand, loading rate of tests, burial depths of pipe and horizontal distance of pipe to footing. The test results showed a significant increase in bearing capacities when embedment ratio of pipe and horizontal distance of pipe to footing were increased. Based on the test results, it can be concluded that the location of pipes and relative density of sand are main parameters that affect the bearing capacity of strip footing. However, loading rate has not considerable effect on bearing capacity.

• Journal of the Korean Geotechnical Society
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• v.25 no.8
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• pp.47-55
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• 2009

This research has the purpose to examine the potential of shell, a byproduct of maritime products to be utilized as alternative environment-friendly construction material by mixing and applying it with residual soit which is used as burial or filling material to recycle it. To that end, the research looked into the mechanical characteristics of shell through cyclic triaxial test by mixing it with residual soil. With the mixing ratios of shell of 5 groups set at 5.0%, 10.0%, 20.0%, 40.0% and 60.0%, the mixture soils was processed through a series of cyclic triaxial tests. And it was shown that liquefation resistance has limitation in the mixed soils with shell substitute content ratios exceeding 20.0%. To increase the liquefaction resistance of the mixed soil, this research has shown that addition of moderate amount of glass fibers would suffice.

• Journal of Ecology and Environment
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• v.38 no.4
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• pp.437-442
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• 2015

Studies to estimate seed longevity and dormancy of creeping bentgrass (Agrostis stolonifera L.) were conducted from 2000 to 2005 at Corvallis and Hermiston, Oregon. Seeds from three transgenic glyphosate resistant creeping bentgrass lines, 48-10, 48-13, and ASR368, and one non-transgenic glyphosate susceptible line, SR1020, were used. Creeping bentgrass seeds were buried at 3, 18 and 31 cm in 2000 and removed 6, 12, 18, 24, and 51 months later. Soil type and climatic conditions were different at the two locations. At Corvallis, the soil was a Malabon silty clay loam, and the winters wet and mild. The soil at Hermiston was an Adkins fine sandy loam, and winters drier and colder. Seeds of all creeping bentgrass lines deteriorated faster at Corvallis than at Hermiston. The estimated half-lives of creeping bentgrass lines buried at Corvallis were 8.4 to 20.2 months, while those buried at Hermiston were 8.4 to 37.7 months. At both sites, seeds of the glyphosate resistant lines, 48-10 and 48-13, deteriorated faster than the susceptible line, SR1020. However, seed deterioration in the resistant line, ASR368, was slower than all other creeping bentgrass lines. Based on the germination test, exhumed intact seeds at Corvallis were more dormant than those at Hermiston. If buried, it could be expected that viable creeping bentgrass seeds will persist more than 4 years after the seeds are introduced to a site, but environmental conditions can influence both seed longevity and dormancy.

• Computers and Concrete
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• v.29 no.2
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• pp.69-79
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• 2022

For long underground box utility tunnels, post-tensioned precast concrete is often used. Between precast tunnel segments, sealed waterproof flexible joints are often specified. Fault displacement can lead to excessive deformation of the joints, which can lead to reduction in waterproofing due to diminished contact pressure between the sealant strip and the tunnel segment. This paper authenticates utilization of a finite element model for a prefabricated tunnel fault-crossing founded on ABAQUS software. In addition, material parameter selection, contact setting and boundary condition are reviewed. Analyzed under normal fault action are: the influence of fault displacement; buried depth; soil friction coefficient, and angle of crossing at the fault plane. In addition, distribution characteristics of the utility tunnel structure for vertical and longitudinal/horizontal relative displacement at segmented interface for the top and bottom slab are analyzed. It is found that the effect of increase in fault displacement on the splice joint deformation is significant, whereas the effects of changes in burial depth, pipe-soil friction coefficient and fault-crossing angle on the overall tunnel and joint deformations were not so significant.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.3_4 s.141
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• pp.470-477
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• 2005

This study was carried out to evaluate the biodegradability of viscose rayon and lyocell fibers, employing soil burial test, activated sludge test and enzymatic hydrolysis. Using X-ray analysis, crystallinity and morphology change was investigated. External changes after degradation were also observed by SEM and digital photographs. Vscose rayon fibers exhibited higher biodegadation than lyocell fibers, indicating that lower crystallinity favored the biodegradation. Among the biodegradability of lyocell fibers there was a tendency that fibers with lower crystallinity and higher moisture regain had higher values. When external changes after degradation being observed, it was shown that there were microorganisms growing on the surfaces of samples accompanying lading and weakening. From these results it was concluded that biodegradability of the specimens was most closely correlated to the moisture regain and crystallinity of fibers which reflects hydrophilicity and internal structure.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.267-275
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• 2020

Purpose: In this study, GPR exploration equipment, spray vehicles and flow meters, core drill, borehole image processing system(BIPS), 3D cavity imagery equipment, and cavity formatting equipment were used to identify this cavity growth process. Method: A certain amount of water was injected in proportion to the mass of the cavity, and the cavity was observed to expand as the injected water was drained out. The cavity rating change was evaluated by quantitatively evaluating the expansion factors and the speed of growth. Results: According to the results of examining the volume change through injection time - injection flow rate - volume increase for the four experimenters, the volume increase decreased as the injection time increased, and there was no further increase in volume if injected for one hour or so. Conclusion: In addition, the injection test analyzed the volumetric variation to determine whether the cause of the cavity occurrence was the effect of the underground burial in the vicinity of the cavity. Therefore, it was found that the cavity expansion is caused by the repetition of the relaxation soil collapse due to the groundwater flow and the loss of the collapsed soil below the cavity.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.1
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• pp.173-182
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• 2001

The physical properties and biodegradability of cellulose fabrics, such as cotton and rayon, are expected to vary with textile care. In this study cotton and rayon fabrics were washed repeatedly with detergents, bleaches, or softeners. The changes of physical properties were investigated by measuring retention of breaking strength, shrinkage, handle, and the fiber surface was observed by SEM. The biodegradability of fabrics was also estimated by soil burial test. The results were as follows. Cotton fabrics laundered repeatedly by detergents and bleaches lost virtually no strength. The breaking strength of the rayon fabrics decreased by about 17%∼25% after repeated launderings. Shrinkage in weft direction was much larger than that in warp direction. Bending rigidities of both fabrics decreased remarkably within 10 wash cycles. Shear rigidity in cotton fabrics increased continuously with repeated washing cycles, however, that in rayon fabrics did not show any change as washing went on. Friction coefficient increased in both fabrics after 10 wash cycles, and this is thought to be attributed to the wrinkle, interlocking of hairs, surface damage resulted from repeated washings. In cotton fabrics made of staple yarns, short hairs on the yarn surface entangled together with repeated launderings. This resulted in the continuous increase in % shrinkage, shear rigidity, friction coefficient. Rayon fabrics made of filament yarns, however, did not show this phenomenon. Softener treated fabrics showed the lowest values in bending rigidity, shear rigidity and friction coefficient because the cationic surfactants adsorbed on the fiber surface behaved like lubricants. The biodegradability of fabrics was noticeably affected by the composition of washing solutions. The fabrics washed with detergents and bleaches were decomposed faster than those washed with the others were and the cotton fabrics washed with detergents and softeners hardly degraded. The fabrics soiled with milk were decomposed almost completely and those soiled with Palmitic acid did not degrade greatly.

• Journal of the Society of Disaster Information
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• v.16 no.1
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• pp.60-69
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• 2020

Purpose: Cavity growth process monitoring is to periodically monitor changes in common size and topography for general and observational grades to predict the rate of common growth. The purpose of this study is to establish a systematic cavity management plan by evaluating the general and observational class community in a non-destructive method. Method: Using GPR exploration equipment, the acquired surface image and the surrounding status image are analyzed in the GPR probe radargram in depth, profile, and cross section of the location. The exact location is selected using the distance and surrounding markings shown on the road surface of the initial detection cavity, and the test cavity is analyzed by calling the radar at the corresponding location. Result: As a result of monitoring tests conducted at a cavity 30 sites of general and observation grade, nine sites have been recovered. Changes in scale were seen in 21 cavity locations, and changes in size and grade occurred in 13 locations. Conclusion: The under road cavity is caused by various causes such as damage to the burial site, poor construction, soil leakage caused by groundwater leakage, waste and ground vibration. Among them, indirect factors could infer the effects of groundwater and localized rainfall.