• Tunnel and Underground Space
• /
• v.20 no.2
• /
• pp.82-91
• /
• 2010

Grouting technology is one of the ground improvement methods used in water controlling and reinforcement of rock mass in underground structure construction. It is necessarily required to find out the characteristics of grout flow through discontinuities in a rock mass for an adequate grout design and performance assessment. Laminar flow is not always applicable in simulating a grout flow in a rock mass, since the rock joints usually have apertures at a micro-scale and the flow through these joints is affected by the joint roughness and the velocity profile of the flow changes partially near the roughness. Thus, the influence of joint roughness and aperture on the grout flow in rough rock joint was numerically investigated in this study. The commercial computational fluid dynamics code, FLUENT, was applied for this purpose. The computed results by embedded Herschel-Bulkley model and VOF (volume of fluid) model, which are applicable to simulate grout flow in a narrow rock joint that is filled with air and water, were well compared with that of analytical results and previously published laboratory test for the verification. The injection pressure required to keep constant injection rate of grout was calculated in a variety of Joint Roughness Coefficient (JRC) and aperture conditions, and the effect of joint roughness and aperture on grout flow were quantified.

• Asian-Australasian Journal of Animal Sciences
• /
• v.21 no.8
• /
• pp.1196-1200
• /
• 2008

An experiment was conducted to evaluate the physiological changes of laying hens subjected to feed removal during induced molting while received probiotics in the drinking water. Post-molt performance and egg quality criteria were also studied. Ninety 78-week-old Hy-line W36 laying hens were divided into two treatment groups according to equal body weight and subjected to induced molting by continuous feed removal until around 30% BW reduction. The experiment lasted 12 wks consisting of 4-wk molting and 8-wk post-molt periods. Treatment 1 received no probiotics and was considered as the control. Treatment 2 was similar to the control except that hens received probiotics in the drinking water at 400 mg/L during feed deprivation. The results indicated that hens in both groups went out of production by Day 5. However, hens received probiotics reached 5 and 50% egg production sooner than the control (30 and 52 days vs. 31 and 54 days). Starvation during molting increased heterophil to lymphocyte (H/L) ratio, hematocrit and plasma T4 and $Na^+$ levels while plasma T3 and Cl- levels were decreased. Probiotics had no significant impact on BW reduction during molt. Post-molt egg production and egg mass were higher in hens which previously received probiotics, but these responses were not significant. However, feed conversion ratio was significantly better in hens which received probiotics. Hematocrit, plasma thyroid hormone concentrations (T3 and T4) and plasma $Na^+$, $K^+$ and Cl- levels during molting were not significantly influenced by supplementation of probiotics. However, H/L ratio showed a significant (p<0.05) reduction in birds which received probiotics suggesting beneficial effects of this product for feed-deprived laying hens. No significant difference was observed in post-molt egg quality criteria.

• Geomechanics and Engineering
• /
• v.19 no.1
• /
• pp.1-9
• /
• 2019

Shallow failures occur frequently in both engineered and natural slopes in expansive soils. Rainfall infiltration is the most predominant triggering factor that contributes to slope failures in both expansive soils and clayey soils. However, slope failures in expansive soils have some distinct characteristics in comparison to slopes in conventional clayey soils. They typically undergo shallow failures with gentle sliding retrogression characteristics. The shallow sliding mass near the slope surface is typically in a state of unsaturated condition and will exhibit significant volume changes with increasing water content during rainfall periods. Many other properties or characteristics change such as the shear strength, matric suction including stress distribution change with respect to depth and time. All these parameters have a significant contribution to the expansive soil slopes instability and are difficult to take into consideration in slope stability analysis using traditional slope stability analysis methods based on principles of saturated soil mechanics. In this paper, commercial software VADOSE/W that can account for climatic factors is used to predict variation of matric suction with respect to time for an expansive soil cut slope in China, which is reported in the literature. The variation of factor of safety with respect to time for this slope is computed using SLOPE/W by taking account of shear strength reduction associated with loss of matric suction extending state-of-the art understanding of the mechanics of unsaturated soils.

• Journal of Soil and Groundwater Environment
• /
• v.12 no.2
• /
• pp.9-19
• /
• 2007

This study investigated the interaction between groundwater and stream water systems, which is caused by the artificial weir on streambed, enforcing external stresses on the groundwater system. The study area is in Nami Natural Recreation Woods located in Chungcheongnam-do Geumsan-gun Nami-myeon Geoncheon-ri. In this study both of hydrophysical methods (hydraulic head) and hyrdochemical investigations (pH, EC, major ion analysis) were applied. In order to identify the relationship between each of study results, cross-correlation analysis is performed. From results of hydrophysical methods, water level fluctuation at BH-14, installed by the weir, shows the double-recession pattern much more frequently and much higher amplitudes than the fluctuation at each of other monitoring wells. Using the results by hydrochemical investigations, hydrochemical properties at BH-14 is similar to the hydrochemical characteristics in stream water. To analyze the interrelationships between the results from each of applied methods, cross-correlation analysis was applied. Results from the correlation analyses, water levels at BH-14 and stream weir showed the highest cross-correlation in hydrophysical aspects. On the other hand, the correlation between stream weir and bridge was the highest in hydrochemical aspects. The difference between the results from each of methods is due that the hydrophysical response at BH-14, such as water level, is induced by the pressure propagation-not with mass transfer, but the hydrochemical interaction, caused by mass transport, takes much more times. In conclusion impermeable artificial weir on streambed changes the interfacial condition between the stream and surrounding aquifers. The induced water flux into the groundwater system during flood period make water level at BH-14 increase instantly and groundwater quality higly similar to the quality of stream water. Referred similarities in both of water level and water quality at BH-14 become much higher when water level at weir grow higher.

• Korean Journal of Remote Sensing
• /
• v.33 no.5_3
• /
• pp.855-866
• /
• 2017

Several research cases using remote sensing methods to analyze changes of storage and dynamics of groundwater aquifer were reviewed in this paper. The status of groundwater storage, in an area with regional scale, could be qualitatively inferred from geological feature, surface water altimetry and topography, distribution of vegetation, and difference between precipitation and evapotranspiration. These qualitative indicators could be measured by geological lineament analysis, airborne magnetic survey, DEM analysis, LAI and NDVI calculation, and surface energy balance modeling. It is certain that GRACE and InSAR have received remarkable attentions as direct utilization from satellite data for quantification of groundwater storage and dynamics. GRACE, composed of twin satellites having acceleration sensors, could detect global or regional microgravity changes and transform them into mass changes of water on surface and inside of the Earth. Numerous studies in terms of groundwater storage using GRACE sensor data were performed with several merits such that (1) there is no requirement of sensor data, (2) auxiliary data for quantification of groundwater can be entirely obtained from another satellite sensors, and (3) algorithms for processing measured data have continuously progressed from designated data management center. The limitations of GRACE for groundwater storage measurement could be defined as follows: (1) In an area with small scale, mass change quantification of groundwater might be inaccurate due to detection limit of the acceleration sensor, and (2) the results would be overestimated in case of combination between sensor and field survey data. InSAR can quantify the dynamic characteristics of aquifer by measuring vertical micro displacement, using linear proportional relation between groundwater head and vertical surface movement. However, InSAR data might now constrain their application to arid or semi-arid area whose land cover appear to be simple, and are hard to apply to the area with the anticipation of loss of coherence with surface. Development of GRACE and InSAR sensor data preprocessing algorithms optimized to topography, geology, and natural conditions of Korea should be prioritized to regionally quantify the mass change and dynamics of the groundwater resources of Korea.

• Smart Structures and Systems
• /
• v.15 no.2
• /
• pp.335-353
• /
• 2015

Previous long-term measurements of the Uldolmok tidal current power plant showed that the structure's natural frequencies fluctuate with a constant cycle-i.e., twice a day with changes in tidal height and tidal current velocity. This study aims to improve structural health monitoring (SHM) techniques for offshore structures under a harsh tidal environment like the Uldolmok Strait. In this study, lab-scale experiments on a simplified offshore structure as a lab-scale test structure were conducted in a circulating water channel to thoroughly investigate the causes of fluctuation of the natural frequencies and to validate the displacement estimation method using multimetric data fusion. To this end, the numerical study was additionally carried out on the simplified offshore structure with damage scenarios, and the corresponding change in the natural frequency was analyzed to support the experimental results. In conclusion, (1) the damage that occurred at the foundation resulted in a more significant change in natural frequencies compared with the effect of added mass; moreover, the structural system became nonlinear when the damage was severe; (2) the proposed damage index was able to indicate an approximate level of damage and the nonlinearity of the lab-scale test structure; (3) displacement estimation using data fusion was valid compared with the reference displacement using the vision-based method.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.11
• /
• pp.4266-4272
• /
• 2010

The purpose of this study was to find the effects of physical activity program on obese young children's body composition and basic motor skills. The physical activity program was conducted with 16 participants whose Kaup Index were higher than 20 were divided into 2 groups(experimental group and control group) for 12 weeks three times a week. Results of the study are as following. First, the physical activity program was found to improve sub-factors of body composition(weight, body fat mass, % body fat, lean body mass and total body water) in the experimental group compared to the control group. There was statistically significant difference between two groups. Second, the physical activity program was found to improve locomotor and manipulation skills of basic motor skills in the experimental group compared to the control group. There was a statistically significant difference between two groups. Based on these results, the physical activity program have positive effects on the changes in obese young children's body composition and basic motor skills.

• Economic and Environmental Geology
• /
• v.34 no.2
• /
• pp.217-226
• /
• 2001

Stable isotope, paleoceanographic and sedimentological analyses were carried out along the core Ml5612 from the Mid-Atlantic Ridge. Distinct negative ${\delta}^{18}O anomalies punctuate the planktonic isotope records and correlate with the Heinrich-IRD cvents. The IRD layer in the corc contains varying amounts of quartz, K-feldspar, plagioclase, calcite, dolomite and mica, in which detrital carbonate contributes between I and 13% (except H3 and H6). Anomalies are strongest in the N. pachydenna (sin.) isotope record. Systematic changes in the ${\delta}^{18}O offset of G. hul/aides and G. inJlata signify variations in mid-latitude thermocline structure. In conjunction with negative benthic ${\delta}^{13}C anomalies, the data document a stronger contribution of a ${\delta}^{13}C depleted, nutrient-rich water mass during the IRD events. The ${\delta}^{13}C amplitude of > 1 $\textperthousand$ between 25 and 57 ka indicates changes between northern source (NADW) and southern source (AABW) water masses at this site. The IRD layers in the core Ml56l2 are correlative with those from the core S075-26KL and DSDP 609. The IRD layers from the Portuguese margin arc coeval with HI, H2 and H4 of the open North Atlantic. This similarity (and/or synchronicity in both regions may have been resulted from common changes in a North Atlantic thermohaline switch.

• Journal of Korean Medicine for Obesity Research
• /
• v.4 no.1
• /
• pp.1-11
• /
• 2004

Objectives: The effects of peroxisome proliferator-activated receptor ${\gamma}2\;(PPAR{\gamma}2)$ Pro12Ala (P12A) polymorphism on body mass index (BMI) and type 2 diabetes are well documented; however, until now, only a few studies have evaluated the effects of this polymorphism on body fat distribution. This study was conducted to elucidate the effects of this polymorphism on computed tomography (CT)-measured body fat distribution and other obesity-related parameters in Korean female subjects. Methods & Results: The frequencies of $PPAR{\gamma}2$ genotypes were: PP type, 93.0%; PA type, 6.8%; and AA type, 0.2%. The frequency of the A allele was 0.035. Body weight (P .012), BMI (P .012), and waist-to-hip ratio (WHR) (P .001) were significantly higher in subjects with PA/AA compared with subjects with PP. When body composition was analyzed by bioimpedance analysis, lean body mass and body water content were similar between the 2 groups. However, body fat mass (P .003) and body fat percent (P .025) were significantly higher in subjects with PA/AA compared with subjects with PP. Among overweight subjects with BMI of greater than 25, PA/AA was associated with significantly higher abdominal subcutaneous fat (P .000), abdominal visceral fat (P .031), and subcutaneous upper and lower thigh adipose tissue (P .010 and .013). However, among lean subjects with BMI of less than 25, no significant differences associated with $PPAR{\gamma}2$ genotype were found, suggesting that the fat-accumulating effects of the PA/AA genotype were evident only among overweight subjects, but not among lean subjects. When serum lipid profiles, glucose, and liver function indicators were compared among overweight subjects, no significant difference associated with $PPAR{\gamma}2$ genotype was found. Changes in body weight, BMI, WHR, and body fat mass were measured among overweight subjects who finished a 1-month weight lose program of a hypocaloric diet and exercise; no significant differences associated with $PPAR{\gamma}2$ genotype were found. Conclusions: The results of this study suggest that the $PPAR{\gamma}2$ PA/AA genotype is associated with increased subcutaneous and visceral fat areas in overweight Korean female subjects, but does not significantly affect serum biochemical parameters and outcomes of weight loss programs.

• Journal of Korean Society of Forest Science
• /
• v.113 no.2
• /
• pp.210-221
• /
• 2024

This study aimed to investigate the effects of forest walking based on an exercise prescription on body composition of older adults. Forty-four older adults (average age: 69.3 ± 3.1 years) participated in this study. The experimental group engaged in forest walking based on a prescribed exercise intensity considering the participants' respective health conditions. The participants walked three times a week for more than an hour each time for 8 weeks. By contrast, the participants in the control group spent their days according to their usual lifestyle. The analysis involved the following: ① a comparison of the measurements taken before and after the 8-week period of forest walking in the experimental group, ② a comparison between pre- and post-study measurements in the control group, and ③ a comparison of the changes (post-study minus pre-study values) between the experimental and control groups. The results were as follows: ① the experimental group showed significant decreases in weight, body fat mass, and body mass index; ② the control group exhibited significant decreases in muscle mass and ratio in right arm and left leg, muscle ratio in trunk, and body water mass in right arm; and ③ weight and body fat index decreased in the experimental group but increased in the control group. In conclusion, forest walking based on an exercise prescription had a positive impact on body composition of older adults.