• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.6
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• pp.713-725
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• 2004

The two-dimensional motion of a freely falling circular cylinder in an infinite fluid is investigated numerically using combined formulation. The effect of vortex shedding on the motion of a freely falling cylinder is clearly seen: as the streamwise velocity of the cylinder increases due to gravity, the periodic vortex shedding induces a periodic motion of the cylinder. This motion in turn affects the flow field, which is manifested by the generation of the angular velocity vector of the cylinder parallel to the cross product of the gravitational acceleration vector and the transverse velocity vector of the cylinder. A correlation of St-Re relationship for a freely falling circular cylinder is drawn from the present results. The Strouhal number for a freely falling circular cylinder is found to be smaller than that for a fixed circular cylinder when the two Reynolds numbers based on the streamwise terminal velocity of a freely failing circular cylinder and the free stream velocity of a fixed one are the same. From "thought experiments", it is shown that the transverse motion of the cylinder plays a crucial role in reducing the Strouhal number and has an effect of reducing the Reynolds number from the viewpoint of the pressure coefficient. The mechanism of this reduction in the Strouhal number is revealed by the fact that the freely falling cylinder experiences a smaller lift force than the fixed one due to the transverse motion resulting in the retardation of the vortex shedding.

• International Journal of Air-Conditioning and Refrigeration
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• v.8 no.2
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• pp.69-79
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• 2000

Falling film rectification involves simultaneous heat and mass transfer between vapor and solution film. In the present work, the adiabatic rectification process of ammonia-water vapor by the falling solution film on the vertical plate was investigated. The continuity momentum, energy and diffusion equations for the solution film and the vapor mixture were formulated in integral forms and solved numerically, The model could predict the film thickness, the pressure gradient, and the mass transfer rate. The effects of Reynolds number and ammonia concentration of solution and vapor mixture, rectifier length, and the enhancement of mass transfer coefficient in each phases were investigated. The stripping of water in vapor mixture occurred near the entrance of ammonia solution, which imposed the proper size of an adiabatic rectifier. Rectifier efficiency increased as film Reynolds number increased and as vapor mixture Reynolds number decreased. The improvement of rectifier efficiency was significant with the enhancement of mass transfer coefficient in falling film.

• Journal of Haehwa Medicine
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• v.21 no.2
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• pp.113-120
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• 2013

The object of this study was to investigate the relation between variables that is related to the general characteristics, fear of falling and falls efficacy. Data were collected from a convenience sample of 105 elders. Fear of falling and falls efficacy are measured structured questionnaires each. This study analyzed by SAS program. There was a significant difference of fear of falling according to education level(p=.003), body mass index(p=.016). There was a significant difference of falls efficacy according to gender(p<.001), education level(p=.047), body mass index(p=.019), number of chronic disease(p=.021). Fear of falling and age(r=0.23, p=.018) had significant positive correlations in the elders. Falls efficacy and number of chronic disease(r=-0.26, p=.010) had significant negative correlations in the elders. Fear of falling and falls efficacy are mutually contradictious concept. Also, both are important for the health of elderly. This result can be used for the elderly care and development of the program for the improvement of the falling efficacy.

• PNF and Movement
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• v.12 no.4
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• pp.259-266
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• 2014

Purpose: The purpose of this study is to describe the effects of proprioceptive neuromuscular facilitation (PNF) on gait speed and genu recurvatum episodes in stroke patients. Methods: The patient is a 58-year-old woman with left hemiplegia who presented with genu recurvatum while walking. Each week the patient received two sessions of PNF that each lasted 45 minutes. During a six-week interval the patient underwent therapeutic exercises and occupational therapy five times a week between the two PNF treatments. During each treatment a preand post-test (a 4 m walk test) was conducted, the patient described their fear of falling down (10-point visual analogue scale), and the number of genu recurvatum episodes was recorded. Results: After the first PNF treatment, the fear of falling down was decreased from 8 points to 7 points, and the number of genu recurvatum episodes decreased from 11 to 6. After the second PNF treatment, the fear of falling down decreased from 6 points to 5 points, and the number of genu recurvatum episodes decreased from 5 to 1. The 4 m walking test time also decreased from 30 seconds to 24 seconds. Conclusion: The PNF treatment is beneficial for reducing the fear of falling down, reducing the number of genu recurvatum episodes, and improving the gait speed of stroke patients.

• Journal of Korean Academy of Nursing
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• v.37 no.7
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• pp.1184-1192
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• 2007

Purpose: The purpose of this study was to examine the relationship among fear of falling, pain, anxiety and depression, and to identify influencing factors in elderly women patients with degenerative arthritis living in the community. Method: The subjects of this study were 297 elderly women patients with degenerative arthritis. Data was collected by personal interviews using questionnaires. Data was analyzed by the SPSS(version 12.0) computer program, and it included descriptive statistics, one-way ANOVA, Pearson correlation coefficient, and Stepwise multiple regression. Results: There was a significant difference (p= .000) in fear of falling according to the level of pain, anxiety, and depression. There was a significant positive correlation among fear of falling, pain, anxiety and depression. Depression, pain, number of medication, age, and anxiety showed significant predictors (43.5%) for fear of falling. Conclusion: This study suggested that thoroughly assessing predictors making an impact on fear of falling in the initial nursing assessment is the most important for falls prevention of elderly women patients with degenerative arthritis in the community.

• Korean Journal of Food Science and Technology
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• v.37 no.5
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• pp.763-767
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• 2005

Effect of ${\alpha}-amylase$ and various emulsifiers on characteristics of bread dough were examined. Fungal or bacterial ${\alpha}-amylase$ and various emulsifiers including monoglyceride (MG), sodium stearoyl-2-lactylate (SSL), and diacetyltartaric acid ester of mono- and diglycerides (DATEM) were added to bread dough both individually and as mixtures. Rheological characteristics of various bread doughs were examined through falling number, farinograph, alveograph, and rapid visco analysis. Results obtained showed falling number decreased via degradation of starch by ${\alpha}-amylase$. In farinogram, addition of ${\alpha}-amylase$ and emulsifiers in dough decreased consistency, water absorption, mechanical tolerance index, and dough development time. Farinogram characteristic was improved by adding SSL+MG to dough formula. Similar to farinogram addition of ${\alpha}-amylase$ and emulsifiers in alveogram of dough decreased overpressure, extensibility, swelling index, and deformation energy. Whereas addition of ${\alpha}-amylase$ did not affect pasting temperature, viscosity of dough tended to decrease.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.3
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• pp.414-421
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• 1999

Falling film rectification involves simultaneous heat and mass transfer between vapor and liquid interface. In the present work, the adiabatic rectification process of ammonia-water vapor on the vertical plate was investigated. The continuity, momentum, energy and diffusion equations for the solution film and vapor mixture were formulated in integral forms and solved numerically. The model could predict the film thickness, the pressure gradient, and the mass transfer rate. The effects of Reynolds number and ammonia concentration of solution and vapor mixture, rectifier length, and the enhancement of mass transfer in each phases were investigated. The stripping of water in vapor mixture occurred new the entrance of ammonia solution, which imposed the proper size of an adiabatic rectifier. Rectifier efficiency increased as film Reynolds number increased and as vapor mixture Reynolds number decreased. The improvement of rectifier efficiency was significant with the enhancement of mass transfer in falling film.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.4
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• pp.225-232
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• 2001

An experimental study is carried out to investigate the characteristics of heat transfer of outside helical tubes. The main heat exchanger consists of twelve curved columns with each 300mm diameter and the total length of 1.2m copper tube having an outer diameter of 19.05mm with 1.5mm thickness. Water flows down the outside of helical tube, where flow patterns are the vertical film falling flow, immerged flow, and mixed-flow which is the combination of film falling flow and immerged flow. Refrigerant 11 flow the inside of the tube countercurrently. The experimental range of inside flow rate is 1.7~3.2$\ell$/min and outside flow rate is 21-33$\ell$/min. The results are presented as Nusselt number with corresponding Reynolds number for variety of outside and inside flow rates. The heat transfer rates of the mixed flow are 8 to 56% higher than those of film falling flow or immerged flow only. Interpretation of the results is given on the basis of physical reasoning and the correlation equations.

• Journal of Mechanical Science and Technology
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• v.17 no.4
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• pp.581-589
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• 2003

Film absorption involves simultaneous heat and mass transfer in the gas-liquid system. While the non-absorbable gas does not participate directly In the absorption process. its pretence does affect the overall heat and mass transfer. An experimental study was performed to investigate the heat and mass transfer characteristics of LiBr-H$_2$O solution flow ing over 6-row horizontal tubes with the water vapor absorption in the pretence of non-absorbable gases. The volumetric concentration of non-absorbable gas, air, was varied from 0.17 to 10.0%. The combined effects of the solution flow rate and its concentration on the heat and mass transfer coefficients were also examined. The presence of 2％ volumetric concentration of air resulted in a 25% reduction in the Nusselt number and 41% reduction in the Sherwood number Optimum film Reynolds number was found to exist at which the heat and mass transfer reach their maximum value independent of air contents. Reduced Nusselt and Sherwood numbers. defined as the ratio of Nusselt and Sherwood numbers at given non-absorbable gas content to that with pure water vapor, were correlated to account for the reduction in the heat and mass transfer due to non-absorbable gases in a falling film absorption process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.1
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• pp.146-151
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• 2017

Quality characteristics (moisture, protein, ash, bulk density, falling number, damaged kernel, and foreign material) of 443 domestic wheat samples harvested between 2011 and 2013 were compared with those of 160 imported wheat samples from the United States, Australia, and Canada. Moisture content of domestic wheat (10.9~13.9%) was generally higher than that of imported wheat (8.0~12.6%). Large variation in protein content was found in domestic wheat compared to imported wheat even though variation in protein content of domestic wheat tended to decrease every year, implying quality control efforts for domestic wheat. A similar trend was observed in ash content, which was approximately 0.1% higher in domestic wheat kernels over 3 years. Imported wheat samples had a falling number of 300 or above. On the other hand, some domestic wheat samples had a falling number of 300, which meant low quality of wheat kernels. Generally, quality variations in domestic wheat kernels decreased over the years; however, it is necessary to maintain minimum requirements of moisture content and falling number for high and consistent quality domestic wheat.