Background: Push-up are effective exercises for shoulder stability. Previous studies have documented the effects of support plane and hand position and width on muscle activities during a push-up.
Objects: This study aimed to investigate the changes in muscle activities in the upper extremity when performing the standard and the knee-flexed push-up with different hand shapes.
Methods: A total of twenty-six healthy males participated in this study. Three different hand shapes (finger abduction, finger adduction, and fists) and two types of push-up posture (standard and knee-flexed push-up) were set as the independent variables. Electrograms were used to measure the muscle activity of the upper trapezius (UT), triceps brachii (TB), pectoralis major (PM), and serratus anterior (SA). Each participant performed the randomly assigned push-up to the sound of the metronome. The mixed-effect linear regression model was used to detect the changes in muscle activities after changing the hand shape and push-up posture. Statistical significance was set at α = 0.05.
Results: The UT muscle activity was statistically significantly higher when performing push-up with fists than finger abduction (p = 0.035) or finger adduction (p = 0.044). During the standard push-up, the muscle activity in all muscles was that the push-up with fists showed the highest muscle activity compared to the finger abduction (p < 0.01) and finger adduction (p < 0.01). Regardless of the shape of the hand, UT had the lowest muscle activity compared to other muscles (p < 0.001). In contrast, the SA muscle had the highest muscle activity among four muscles during the standard push-up.
Conclusion: Based on the results of this study, we suggest hand shape is related to the difficulty level of push-up either in the standard or the knee-flexed push-up, especially in the push-up with fists. In addition, knee push-up can be recommended as shoulder musclestrengthening exercises for individuals with low shoulder muscle strength.
본 연구는 서울시 중학교에 재학 중인 학생 252명을 조사하여 남녀별로 국물음식을 통한 나트륨 섭취량의 차이를 조사하였으며, 실제로 배식받은 양과 섭취 형태에 따른 나트륨 섭취량을 계산하였다
본 연구에서 얻어진 결과를 요약하면 다음과 같다
1. 조사 대상자들의 성별은 남자 116명, 여자 136명, 학년 별로 1학년 86명, 2학년 77명, 3학년 89명이었다.
2. ‘국 없는 날’의 인식 여부에서 ‘국 없는 날’을 알고 있는 학생은 남자 58.6%. 여자 75.7%로 ‘국 없는 날’의 운영 횟수 질문의 응답으로는 1달에 1번으로 정확하게 알고 있는 학생은 남자는 55.2%, 여자는 62.5%로 나타났고, ‘국 없는 날’의 운영 이유로 ‘나트륨을 줄이기 위해서’라고 정확하게 답한 학생은 남자 61.2%, 여자 77.2%로 나타났다. ‘국 없는 날’의 인식 여부는 성별간의 유의한 차이가 있는 것으로 나타났으며, 여자가 남자보다 더 많이 알고 있는 것으로 나타났다. 학교 급식에서 저감화 나트륨 계획으로 운영되고 있는 ‘국 없는 날’을 정확히 알고 있는 경우는 59.1%의 학생만이 알고 있는 것으로 나타났다.
3. 나트륨 줄이기 교육을 받은 적이 있는 학생은 50명, 나트륨을 줄이기 위한 노력 여부는 노력한 적이 있는 학생도 53 명으로 나타나 전체 252명에서 채 20%를 넘지 않는 것으로 나타났다. ‘국 없는 날’의 운영도 나트륨 줄이기 교육의 일부임에도 불구하고, 나트륨 줄이기 교육 여부에서 남자 17.2%, 여자 22.1%만이 교육을 받았다고 답해 이에 관한 관심이 없는 것으로 나타났다. 이러한 인식실태는 ‘국 없는 날’의 운영만으로 나트륨 저감화 교육이 제대로 이루어지지 않는다는 것을 보여준다.
4. 학교 급식에서 제공된 국물음식의 섭취 형태에서 부대찌개는 건더기와 국물을 모두 섭취하는 인원이 71.8%로 가장 높았고, 그 다음으로는 설렁탕 69.8%로 나타났다. 우동은 건더기만 섭취하는 인원이 25.0%로 가장 높은 비율을 나타냈으며, 그 다음으로는 조랭이떡국 22.2%로 나타났다. 국물만 섭취한 경우에는 동태찌개 25.4%, 미소국 25.0% 순으로 나타났다. 북어국은 아예 국물음식을 섭취하지 않음이 36.1%로 가장 높아 선호하지 않는 것으로 나타났다.
5. 학교 점심급식에서 제공된 국물음식에 의하여 섭취하는 나트륨량은 국물음식 섭취행태를 고려한 경우 점심식사 한끼 국물음식 평균 379.6±183.9 mg, 고려하지 않은 경우는 556.8±190.6 mg으로 나타났으며, 메밀소바, 부대찌개, 우동순으로 높게 나타났다. 38가지의 모든 국물음식에서 나트륨 섭취량이 국물 섭취 행태에 따라 유의한 차이가 나타났다. 국물 섭취 행태를 고려한 경우와 고려하지 않은 경우에 나트륨 섭취량이 97.7~411.8 mg의 차이를 보이고 있었고, 평균 차이는 177.2 mg으로 나타났다. 몇 개의 음식에서는 차이가 있었지만 학교에서 제공된 전체 국물음식을 통한 평균 나트륨섭취량은 행태를 고려하던 하지 않던 남녀의 차이가 나타나지 않았다. 결론적으로 국물음식을 섭취 행태에 따라 섭취하는 나트륨 함량이 다르게 나타난 결과를 바탕으로 국물과 건더기, 국물만, 건더기만의 각각의 나트륨 데이터베이스를 이용하여 나트륨 섭취량을 분석하는 것이 필요하다.
The annoyance potential for odor sources can be evaluated by separation distances. A separation distance between a standard pig farm and a residential area was investigated by the AERMOD model. The studied area comprised four sites in Korea. The study sites were Paju, Yangpyeong, Suwon, and Icheon, respectively. The separation distances criteria of the three reference Odor Impact Criteria (OIC) were used to evaluate the separation distance. Results show that separation distances for the four sites were calculated 20 m from the fence in the existing pig farm criteria case [exceedance probability P (%) = 2.0% and concentration = 6 OU] in Ireland. In the case of the new pig farm criteria [(exceedance probability P (%) = 2.0% and concentration = 3 OU) of Ireland, results show that the separation distances of the four locations were between 120 m and 145 m from the fence. These values were about 3.0~4.5 times larger than those of the existing pig farm criteria case. In the case of a concentration of 1 OU and the exceedance probability P (%) of a 2.0% criteria, the separation distances of the four sites ranged from 250 m to 290 m.
Odor dispersion from road emissions were investigated using CFD (Computational Fluid Dynamics). The Shear Stress Transport k-ω model in FLUENT CFD code was used to simulate odor dispersion around the road. The two road configurations used in the study were at-grade and fill road. Experimental data from the wind tunnel obtained in a previous study was used to validate the numerical result of the road dispersion. Five validation metrics are used to obtain an overall and quantitative evaluation of the performance of Shear Stress Transport k-ω models: the fractional bias (FB), the geometric mean bias (MG), the normalized mean square error (NMSE), the geometric variance (VG), and the fraction of predictions within a factor of two of observations (FAC2). The results of the vertical concentration profile for neutral atmospheric show reasonable performance for all five metrics. Six atmospheric stability conditions were used to evaluate the stability effect of road emission dispersion. It was found that the stability category D case of at-grade decreased the non-dimensional surface odor concentration smaller 0.78~0.93 times than those of stability category A case, and that F case decreased 0.39~0.56 times smaller than those of stability category A case. It was also found that stability category D case of filled road decreased 0.84~0.92 times the non-dimensional surface odor concentration of category A case and stability category F case decreased 0.45~0.58 times compared with stability category A case.
Air pollution dispersion from rooftop emissions around hexahedron buildings was investigated using computational fluid dynamics (referred to hereafter as CFD). The Shear Stress Transport (referred to hereafter as SST) k-ω model in FLUENT CFD code was used to simulate the flow and pollution dispersion around the hexahedron buildings. The two buildings used in the study had the dimensions of H: L: W (where H = height, L = length, and W = width) with the ratios of 1:1:1 and 1:1:2. Experimental data from the wind tunnel obtained by a previous study was used to validate the numerical result of the hexahedron building. Five validation metrics are used to obtain an overall and quantitative evaluation of the performance of SST k-ω models: the fractional bias (FB), the geometric mean bias (MG), the normalized mean square errors (NMSE), the geometric variance (VG), and the factor of 2 of the observations (FAC2). The results of vertical concentration profile and longitudinal surface concentration of the 1:1:2 building illustrate the reasonable performance for all five metrics. However, the lateral concentration profile at X = 3H (where X is the distance from the source) shows poor performance for all of the metrics with the exception of NMSE, and the lateral concentration profile at X = 10H shows poor performance for FB and MG.
This paper presents the results of a human health effect for H2S emission standard of incinerators in Seoul, Korea. The four selected incinerators of Gangnam, Mapo, Nowon and Yangcheon were chosen as the domains of study. Air dispersion modelling (AERMOD) was used to predict the ground level concentration within 3 km distance of the emission source. The emissions at the incinerators studied ranged from 0.0721 (Yangcheon) to 0.3007 g/s (Gangnam). These values were about three orders of magnitude smaller than that of Canadian geothermal power plants. Based on the health risk assessment, different health risks were identified for short-term and long-term dispersion of the studied areas. The short-term hazard quotient (HQ) for H2S of Gangnam and Nowon incinerators were greater than the acceptable limit (i.e., 1.0) in some locations. However the long-term HQ for H2S of all incinerators were lower than the acceptable limit.
This study was undertaken to examine the knowledge about food culture and intakes of traditional food in Korean and Japanese elementary school students. In 2012 and 2013, a total of 265 students were surveyed, consisting of 73 Korean fifth graders and 192 Japanese sixth graders. The questionnaire comprised of queries on general items, the recognition and sampling of traditional and celebration foods, the knowledge about the partner country's food culture, and the frequency of consuming the partner country's foods. As a result of this study, the frequency of consuming their own country's traditional foods for Korean children (3.1 out of 5.0 points) and Japanese children (3.2 out of 5.0 points) was similar to each other. Japanese children reported to eat Korean foods (2.9 points) more frequently than those of Korean children to eat Japanese foods (2.4 out of 5.0 points) (p<0.001). However, the Korean children reported to have more experience on given typical Japanese foods than Japanese children reported about Korean foods. Further studies are needed for the perception on traditional foods in Korean and Japanese children. The results of this study can be used as a basic data to succeed and develop traditional food cultures.
This paper presents the performance of a CFD model for the near field dispersion of odor from rooftop emissions. The FLUENT Shear-Stress Transport (SST hereinafter) k-ω turbulence model was used to simulate odor dispersion from a rooftop odor vent. The results were compared with a wind tunnel experiment and the calculated results of ASHRAE 2003 and 2007. The FLUENT SST k-ω turbulence model provided good results for making reasonable predictions about the building rooftop surface normalized dilution. It was found that increasing the vent height (from 1 m to 7 m) reduces rooftop surface normalized dilution. ASHRAE 2003 and ASHRAE 2007 performance measures are generally not as good as FLUENT SST k-ω turbulence model performance measures, with larger MG (the geometric mean bias, VG (the geometric variance), NMSE (the normalized mean square error), FB (Fractional bias), and smaller FAC2 (the fraction of predictions within a factor of two of observations).
In this study we investigated odor (hydrogen sulfide) dispersion around a cubic building by using commercial FLUENT CFD code. The FLUENT Shear-Stress Transport (hereafter SST) k-ω turbulence model was used to simulate odor dispersion from an odor source. The results were compared with a wind tunnel experiment and other simulation results. SST k-ω turbulence model provided good grounds for making reasonable predictions about the building surface concentrations and concentration profiles of selected leeward positions of the cubic building. It was found that a vent, which was positioned 7 m above the top of the square building center, decreased the plume length lower by 0.73 and increased the plume height by 1.43 compared to roof top vents. It was also found that by increasing the vent height there a corresponding decrease in the maximum dimensionless concentration around the roof surface.
Atmospheric stability is an important parameter which effects pollutant dispersion in the atmospheric boundary layer.The objective of this paper was to verify the effect of stability conditions on odor dispersion downwind from anarea source using computational fluid dynamic (CFD) modeling. The FLUENT Realizable k-ε model was used tosimulate odor dispersion as released by an odor source. A total of 3 simulations demonstrated the effects of unstable,neutral, and stable atmospheric conditions. Unstable atmospheric stability conditions produced a shorter odor plumelength compared with neutral and stable conditions because of stronger convective effects. Like other studies,unstable atmospheric condition produced higher plume height compared with neutral and stable conditions.
우리나라에서 악취 규제는 배출원의 부지경계선과 배출구에서 농도 규제치를 사용한다. 그러므로 수용체에서 정확한 체감악취의 유무를 쉽게 판단하기는 곤란하다. 비록 개개인의 악취에 대한 응답을 결정하는 변수는 다양하고 응답 종류도 광범위하게 나타나지만, 일반적으로 악취에 대한 규제는 다양한 변수를 고려하여 구성되며, 이들 변수에는 악취 발생빈도, 강도, 기간, 불쾌도, 지역 변수 등이 있다. 본 연구에서는 매사추세츠(미국), 뉴질랜드, 덴마크, 네덜란드, 호주 서부, 타이완 등 6개 지역의 악취 규제를 사용하여 소각장 주변에서 악취 영향 거리를 비교하였다. 악취 영향 거리를 평가하기 위하여 이들 6개 지역 규제는 악취 농도와 허용 빈도를 고려하고 있다. 연구 결과에 의하면 악취에 의한 영향 거리는 0.5~1.4 km의 범위로 나타났다. 악취 농도를 고정하고 허용 빈도를 변경하는 경우 허용 빈도가 높을수록 영향 거리는 크게 나타났다. 허용 빈도를 고정하고 농도를 변화시키는 경우 농도가 높으면 영향거리가 줄어들었다. 결론적으로 악취 영향 범위는 악취 농도뿐 아니라 허용 빈도에 따라 변화하였다.
In this paper, a comparative cold weather concrete member test was conducted with gang form and euro form, which are generally used as forms for construction in Korea. Three members were fabricated for the comparative test: the member with the general gang form and euro form, the member with the existing insulation gang form on the outside and the general form on the inside, and the member with the existing insulation gang form on the outside and the newly developed insulation euro form on the inside. In this test, ready-mixed concrete with a nominal strength of 24 MPa that met a certain standard was cast in the cold weather concrete condition at a temperature of 0℃ (5℃ ～–5℃), which is lower than the cold weather concrete management standard temperature in Korea 4℃ mean daily temperature. The standard water curing compressive strength, core compressive strength and temperature history were measured and comparatively examined for the general gang form-general euro form and insulation gang form-general euro form members that were cured at a certain inside temperature, and for the insulation gang form-insulation euro form member that was cured without additional temperature control.
Ultra high performance concrete which has recently been studied was developed to complement the brittle behaviour and dynamic uppermost limit of high strength concrete. Fiber reinforced concrete which mixed steel fiber is receiving attention as an alternative about this and is being developed to complement the disadvantages of high strength concrete including lower toughness coefficients and crack resistance and spalling in fires. Review about fiber reinforced ultra high strength concrete that this study tries to treat includes reduction of self shrinkage generated by high cement content per unit volume of concrete, evaluation of compression and tension strength to lower internal and external spalling resistance and fragility factors of member of framework, and flow characteristics of concrete which doesn't harden according to steel fiber amounts and used materials. As the result, the more fiber reinforcement increases, the more compression and tensile strength increase and deformation control of cement matrix and improvement of energy absorption ability showed the great effect in shrinkage reduction.
Aluminum oxide 지지체를 사용하여 루테늄 촉매가 개발되었고, 이 루테늄 촉매는 수중에서 일차 아민또는 니트릴을 기질로 하여 일차 아미드 합성에 적용되었다. 방향족, 비활성화 된 지방족, 환 모양의 헤테로 원자 등의 다양한 기질들의 아민 또는 니트릴이 최종 생산물인 일차 아미드로 높은 수율을 보이며전환되었다. 그리고 이 반응들에서 산 또는 염기와 같은 첨가물이나 일반적인 산화제 등의 도움없이 반응이 수중에서 진행되었다. 사용된 촉매는불균일 촉매임이 분명하였고, 그 촉매는 단순여과에 의해metal-leaching 없이 회수되었으며, 회수된 촉매는 촉매 성능의 변화없이 여러 번 재사용되었다.
In this study we investigated the air pollutants dispersion around depressed road using commercial FLUENT CFD code. In order to find optimal turbulence model which simulates air pollution dispersion around. depressed road, we used the realizable k-ε model, the RNG k-ε model, and the Shear-Stress Transport k-⍵turbulence model in FLUENT CFD code. The results were compared with the wind tunnel experiments. Realizable k-ε turbulence model provided the best prediction for the surface concentrations and concentration profiles of selected downwind positions of the depressed road. It was found that a noise barrier, which positioned around the depressed road, decrease the horizontal impact distance lower 0.46~0.81 times and change the vertical air pollution impact distance larger 0.95~1.47 times than those of no barrier case. It was also found that two or three noise barriers increase 1.33-1.42 times the vertical air pollution impact distance. It contributes the decrease of horizontal air pollution impact distance 0.44~0.60 times compare with no barrier case.
This paper intends to review possible application in the high strength area through compressive strength estimation of the simulated high strength concrete member using Rock Test Hammer and suggest it as a reference data for the strength estimation technique of the ultra high strength concrete in the future. From the results of test, in the low strength area less than 15MPa and normal strength area in 15∼60MPa, as shown on the existing studies, it is indicated that P Type Schmidt Hammer in the low strength area and N Type Schmidt Hammer in the normal strength area have high correlation of rebound-compressive strength. As the Rock Test Hammer indicated more or less reduced accuracy in the low strength area and the normal strength area but high correlation on the high strength area (50∼100MPa) defined on this test, it is determined that it would be possible to make the fastest and simplest compressive strength estimation on the site where the high strength concrete is applied. As was resulted above the experiments, on the basis of the result of Rebound Hardness Method and Compressive Strength on the high strength area which is over 50MPa, the conclusion is drawn which is Fc=4.409e0.059R through regression analizing the relations of Compressive Strength which is based on Rebound Hardness Method.
In this study, expedite curing period at curing temperature being 40, 60, 80℃ similar to strength of standard 28days curing temperature to confirm methods and applicability of early estimation of strength by warm water curing. Also, checked the effect related to different conditions such as using various kinds of material, differentiating quantity of material, with or without fiber mixing at same rate of water-bonding material. Existing method proposed by KS and JIS to estimate strength of 28 days standard curing temperature curing for 7days at 40℃ is not relevant because it takes so long to estimate strength. Already known method of estimating strength of 28days standard curing temperature curing for 3days in 60℃ warm water, too, is not relevant to apply 3day cycle of super high-rise. It also had the problem which didn’t consider fiber mixed concrete. According to the result of experiment, traits and rate of strength revelation were different relating to the kinds and quantity of bonding material. Strength value of mix without fiber was higher than that of mix with fiber, but without any relation to that, over 96% of similar confidence level with strength of 28 days standard curing temperature was shown in 7 days at 40℃, 3 days at 60℃, 2days at 80℃. Confidence level of estimation method of 2 days at 80℃ was similar to those of estimation methods of 4 days at 40℃, 3 days at 60℃, so it(2 days at 80℃) is regarded as the most relevant method because it’s possible to estimate strength fastly. As a result it can be said that early quality control of recently increasing super high-rise may be possible through estimation method of 2 days at 80℃.
The dispersion of air pollution in complex situations such as the cases of the filled road is a significant problem for the public safety and living quality. Application of computational fluid dynamics (CFD) helps to build the model calculation in order to estimate the dispersion of air pollutants. In order to assess its accuracy, this study used the Realizable k-ε model, the RNG k-ε model, and the Shear-Stress Transport k-ω turbulence model in FLUENT CFD code. The results were compared with the wind tunnel experiments. The Realizable k-ε turbulence model provided the best prediction for the surface concentration and concentration profiles of selected downwind positions of the filled road. It was found that a noise barrier, which positioned on the filled road, increases the vertical air pollution impact distance larger 1.75~1.92 times and decrease the horizontal impact distance lower 0.46~0.54 times than those of no barrier case. It was also found that two or three noise barriers increase 1.63~1.79 times the vertical air pollution impact distance. It contributes the decrease of horizontal air pollution impact distance 0.49~0.63 times compare with no barrier case.
This study investigated impact of odors from industrial areas using the FIDOL concept. The studied region was the Seobu industrial complex in Korea. The USEPA dispersion model, AERMOD, was used to calculate odor concentration. The results show that the size of the impact areas of lower regulation compliance frequency is smaller than that of the areas of higher regulation compliance frequency. The results also showed that increasing the concentration of odor unit (OU) decreased the size of the impact area and the maximum impact distance. Calculated odor impact area, using Massachusetts (USA) regulations, had the smallest impact area among selected locations such as Massachusetts (USA), New Zealand, Denmark, and the Netherlands. Denmark’s regulations had the largest impact area.
Noise barriers along the road do not only block the traffic noise but also prevent traversing the car exhausts. These barriers may affect air pollution dispersion, leading to increase vertical mixing due to the upwind deflection of air flow caused by the noise barriers. In this study we investigated the air pollution dispersion around multi-noise barriers using commercial software FLUENT. Investigated cases were 8 cases which had from zero to three noise barriers and two emission sources. Simulated results show noise barriers increase the vertical air pollution impact distance larger 1.7~2.1 times than that of no barrier case. It was also found that noise barriers decrease the horizontal air pollution impact distance lower 0.6~0.8 times than that of no barrier case.