• Journal of The Korean Society of Integrative Medicine
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• v.11 no.4
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• pp.51-60
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• 2023

Purpose : The purpose of this study was to determine the effect of pelvic floor muscle exercise (PFME) on an unstable support surface on maximal inspiratory pressure (MIP), maximum expiratory pressure (MEP), and abdominal muscle thickness as a method for effective PFME. Methods : This study was performed on 22 subjects. They were matched and divided into two groups based on body mass index; the experimental group (EG) performed PFME on a foam roller (n= 11), the control group (CG) performed PFME on a stable support surface (n= 11). Kegel exercise was performed with 10 seconds of contraction, 10 seconds of relaxation, and 4 sets of 10 reps per set. Both of group executed the exercise 3 times a week for 2 weeks. MIP and MEP was measured using a spirometer. Abdominal muscle thickness was measured using ultrasound. The paired t-test was used to compare difference on each group and the comparison between groups was analyzed using the independent t-test. A significance level of α= .05 was used to verify statistical significance. Results : The EG showed a significant increase in the MEP (p<.05). The CG showed a significant increase in the MEP (p<.05). There was no significant difference in the two groups (p>.05). The EG showed a significant increase in the external oblique, internal oblique and transverse abdominis (p<.05). The CG showed a significant increase in the internal oblique (p<.05). There was no significant difference in the two groups (p>.05). Conclusion : Based on the results of this study, additional research should be conducted to correct the limitations of this study to confirm that PFME performed on a foam roller has a positive effect on respiratory muscle strength and abdominal muscle thickness.

• Journal of the Korean Society of Safety
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• v.2 no.1
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• pp.31-41
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• 1987

The surface rolling method which is one of the plastic deformation processes increases the surface roughness with reduction of diameter and hardness. In this study, three NACHI 6000 ZZ bearing were used for surface rolling tool on a mild steel. The following results have been obtained with the mild steel. 1) The load is major factor in getting fine surface roughness of roller fininshing after grinding. The optimal surface roughness of SS40 steel can be obtained at the contact pressure of $210kgf/cm^2$. But, Better surface roughness can not be expected, Due to flaking phenomena at more than 300 kgf/cm of contact pressure. 2) At the contact pressure range of $200kgf/cm^2{\sim}210kgf/cm^2$ for optimal surface roughness, The surface hardness increased to Hv 200~Hv 240 from Hv 125 before surface rolling. 3) Within the diameter variation of $13{\mu}m$ the surface roughness and the surface hardness were increased, but out of variation of $14{\mu}m$. The surface roughness become worse and the surface hardness was increased.

• Textile Coloration and Finishing
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• v.23 no.2
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• pp.131-139
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• 2011

This study surveyed on the synthesis of one-step type hydrophilic non-porous PU resin and the physical property of the coated fabric for the garment. Three kinds of chain extender such as MEG, 1,4-BD and NPG were used for the preparation of one-step type hydrophilic non-porous PU resin in order to examine the effect of chain extender on the physical properties of PU-coated fabric. And the effects of isocyanate on the physical properties of PU coated fabric were surveyed by mixing with various TDI and MDI ratios. In addition, the physical properties of the coated fabric treated with one-step type hydrophilic non-porous PU resin were examined according to the pre-treatment conditions such as cire finishing. Finally, the washing durability of the coated fabrics was assessed. The coated fabrics treated with PU resin synthesized with PEG1000, MEG and TDI/MDI (6/4) showed the best physical properties. Considering the pre-treatment conditions, best performance of hydraulic pressure, water vapor permeability, and water repellency were obtained with top roller rotation ratio of 150% under 50 ton pressure at $170^{\circ}C$.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.435-440
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• 2000

It is important to pay careful attention to construction backfill for the structural integrity of concrete box culvert. The stability of the surrounding soil is important to the structural performance of most culverts. Good compaction by the dynamic compaction roller with big capacity is as effective as good backfill materials to increase the structural integrity of culvert. However structural distress of the culvert could be occur due to the excessive earth pressure by dynamic compaction load. In this study, 16 box culverts were constructed with various compaction materials and construction methods. Three types of on-site soils such as subbase, subgrade and roadbed materials were used as backfill materials in the test program. Compaction methods were adapted based on the site conditions. In most cases, dynamic compaction rollers with 10 to 16 ton weights were used and vibration speed were applied from 2400 to 2500 rpm for the great compaction energy. Some backfill compactions with good quality soils were carried out to examine the effect of EPS(Expanded Polystyrene) panels with changes of compaction thickness. This paper presents the main results of the research conducted to access the engineering performance of the backfill materials. The characteristics of earth pressures are discussed. It is observed that subgrade and roadbed materials are needed more careful compaction than subbase materials. It is shown that EPS panels are effective to mitigate dynamic lateral earth pressure on the culverts. It is also obtained that the dynamic pressure depends on the soil properties. In addition, the coefficient of dynamic earth pressure (K$\sub$dyn/=ΔP$\sub$H/ ΔP$\sub$V/) during compaction is discussed.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.10
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• pp.1131-1140
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• 2011

A new rotary gravure-offset printing unit is constructed by paralleling a gravure plate cylinder, a blanket cylinder and a impression roller. A Muti-Unit Gravure-Offset Printing Press(MUGOP) equipped with a series of the 3 printing units is utilized for roll-to-roll fine printing. Its core technology is precise over-piling printing of fine patterns. The severe problems of 'slurring' and 'doubling' in typical offset printing are unavoidable, which can be eliminated by applying a soft pad-type blanket cylinder and the unique 'true rolling' technique. Nip pressure between the blanket cylinder and the plate cylinder is measured by the constant pressure control system which equipped with load cells attached on the cylinders' axes. The running circumference of the blanket cylinder is increased to reach the same circumference of the plate cylinder as the pressure increasing, so that the specifications of the blanket cylinder is determined by the relationships of its shore hardness, diameter and nip pressure. When a softer blanket is used, a blanket cylinder of smaller diameter could give higher nip pressure. Realization of the true rolling technique on the MUGOP makes multilayer printing possible as well as fine printing in printed electronics.

• Journal of Biosystems Engineering
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• v.1 no.1
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• pp.15-15
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• 1976

In analyzing the operational characteristics of a rice whitening machine, the internal radial pressure of the machine was measured using strain gage equipment. Changes in cylinder and feed screw configurations, screen type, cylinder speed and counter-pressure levels were examined to determine their impact on the quality and quantity of milled rice and the performance of the machine. The results are summarized as follows: 1. The internal radial pressure in the whitening chamber varied with the surface condition of the grain being processed. During the first or second pass through the machine, pressure was relatively low, reached a maximum after two to three passes with combinations I and II, three to six with combination III and then began to fall. 2. The pitch of the feed screw and the size of the feed gate opening which determine the rate of entry of grain into the whitening chamber, appeared to be the most important factor aff-::cting the degree of radial pressure, quality and quantity of milled rice and the efficiency of the machine. Using a feed screw with a wide pitch (4.8cm), radial pressure was relatively high and head rice recovery ratio \vere quite low. In this case capacity and machine effic?iency were much higher than obtained when using a feed screw with a narrow pitch (2.3cm). Very significant responses in radial pressure, head rice recovery rates and machine capacity were observed with changes in cylinder speed and counter-pressure levels when using the wide pitch feed screw. 3. The characteristics of the screen which surrounds the whitening chamber had an important effect on whitening efficiency. The existence of small protuberances on the original screen resulted in significant increases in both machine capacity and efficiency but without a significant decrease in head rice recovery or development of excessive radial pressure. Further work is required to determine the effects of screen surface conditions and the shape of the cylinderical steel roller on the rate of bran removal, machine efficiency and recovery rates. The size of the slotted perforations 0:1 the screen affects total milled rice recovery. The opening size on the original screen was fabricated to accommodate the round shape of Japonica rice varieties but was not suitable for the more slender Indica type. Milling Indica varieties with this screen resulted in a reduction in total milled rice recovery. 4. An increase in cylinder speed from 380 to 820 rpm produced a positive effect on head rice recovery for all machine combinations at every level of counter-pressure used in the tests. Head rice recovery was considerably lower at 380rpm using a wide screw pitch when compared to the results obtained at speeds from 600 to 820 r.p.m. The effects of cylinder speed On radial pressure, capacity and machine efficiency showed contrasting results, depending on the width of the feed screw pitch. With a narrow feed screw pitch (2.3cm), a direct proportional relationship was observed bet?ween cylinder speed and both radial pressure and machine efficiency. In contrast, using a 4.8 centimeter pitch feed roller produced a series of inverse relationships between the above variables. Based on the results of this study it is recommended when milling Indica type long grain rice varieties that the cylinder speed of the original machine be increased from 500-600 rmp up to a minimum of 800 rpm to obtain a greater abrasive effect between the grain and the screen. The pitch of the feed screw should be also reduced to decr?ease the level of internal radial pressure and to obtain higher machine efficiency and increased quality of milled rice with increased cylinder speeds. Further study on the interaction between cylinder speed and feed screw pitch is recommended. 5. An increase in the counter pressure level produced a negative effect On the head rice recovery with an increase in radial pressure, capacity, and machine efficiency over all combinations and at every level of cylinder speed. 6. Head rice recovery rates were conditioned primarily by the pressure inside the whitening chamber. According to the empirical cha racteristics curve developed in this study, the relationships of head rice recovery ($Y_h$) and machine capacity ($Y_c$/TEX>) to internal radial pressure ($X_p$) followed an inverse quadratic function and a linear function respectively: $$Y_h^\Delta=\frac{1}{{1.4383-0.2951X_p^\ast+0.1425X_p^{\ast\ast}}^2} , (R^2=0.98)$$$$Y_c^\Delta=-305.83+374.37X_p^{\ast\ast}, (R^2=0.88)$$The correlation between capacity and power consumption per unit of brown rice expressed in the following exponential function: $$Y_c^\Delta=1.63Y_c^{-0.7786^\{\ast\ast}, (R^2=0.94)$$These relationships indicate that when radial pressure increases above a certain range (1. 6 to 2.0 kg/$cm^2$ based On the results of the experiment) head ricerecovery decrea?ses in a quadratic relation with a inear increase in capacity but without any decrease in power consump tion per unit of brown rice. On the other hand, if radial pressure is below the range shown above, power consumption increases dramatically with a lin?ear decrease in capacity but without significant increases in head rice recovery. During the operation of a given whitening machine, the optimum radial pressure range or the correct capacity range should be selected by controlling the feed rate and/or counter-pressure keeping in mind the condition of the grain, particulary the hardness. It was observed that the total number of passes is related to radial pessure level, feed rate and counter-pressure level. The higher theradial pressure the fewer num?ber of pass required but with decreased head rice recovery. In particular, when using high feed rates, the total number of passes should be increased to more than three by reducing the counter-pressure level to avoid decreaseases in head rice recovery (less than 65 percent head rice recovery on the basis of brown rice) at every cylinder speed. 7. A rapid rise in grain temperature seemed to have a close relationship with the pressure generated inside the whitening chamber and, subsequently with head rice reco?very rates. The higher the rate of increase, the lower were the resulting head rice recoveries.

• Journal of Biosystems Engineering
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• v.1 no.1
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• pp.17-48
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• 1976

In analyzing the operational characteristics of a rice whitening machine, the internal radial pressure of the machine was measured using strain gage equipment. Changes in cylinder and feed screw configurations, screen type, cylinder speed and counter-pressure levels were examined to determine their impact on the quality and quantity of milled rice and the performance of the machine. The results are summarized as follows: 1. The internal radial pressure in the whitening chamber varied with the surface condition of the grain being processed. During the first or second pass through the machine, pressure was relatively low, reached a maximum after two to three passes with combinations I and II, three to six with combination III and then began to fall. 2. The pitch of the feed screw and the size of the feed gate opening which determine the rate of entry of grain into the whitening chamber, appeared to be the most important factor aff-::cting the degree of radial pressure, quality and quantity of milled rice and the efficiency of the machine. Using a feed screw with a wide pitch (4.8cm), radial pressure was relatively high and head rice recovery ratio \vere quite low. In this case capacity and machine effic\ulcorneriency were much higher than obtained when using a feed screw with a narrow pitch (2.3cm). Very significant responses in radial pressure, head rice recovery rates and machine capacity were observed with changes in cylinder speed and counter-pressure levels when using the wide pitch feed screw. 3. The characteristics of the screen which surrounds the whitening chamber had an important effect on whitening efficiency. The existence of small protuberances on the original screen resulted in significant increases in both machine capacity and efficiency but without a significant decrease in head rice recovery or development of excessive radial pressure. Further work is required to determine the effects of screen surface conditions and the shape of the cylinderical steel roller on the rate of bran removal, machine efficiency and recovery rates. The size of the slotted perforations 0:1 the screen affects total milled rice recovery. The opening size on the original screen was fabricated to accommodate the round shape of Japonica rice varieties but was not suitable for the more slender Indica type. Milling Indica varieties with this screen resulted in a reduction in total milled rice recovery. 4. An increase in cylinder speed from 380 to 820 rpm produced a positive effect on head rice recovery for all machine combinations at every level of counter-pressure used in the tests. Head rice recovery was considerably lower at 380rpm using a wide screw pitch when compared to the results obtained at speeds from 600 to 820 r.p.m. The effects of cylinder speed On radial pressure, capacity and machine efficiency showed contrasting results, depending on the width of the feed screw pitch. With a narrow feed screw pitch (2.3cm), a direct proportional relationship was observed bet\ulcornerween cylinder speed and both radial pressure and machine efficiency. In contrast, using a 4.8 centimeter pitch feed roller produced a series of inverse relationships between the above variables. Based on the results of this study it is recommended when milling Indica type long grain rice varieties that the cylinder speed of the original machine be increased from 500-600 rmp up to a minimum of 800 rpm to obtain a greater abrasive effect between the grain and the screen. The pitch of the feed screw should be also reduced to decr\ulcornerease the level of internal radial pressure and to obtain higher machine efficiency and increased quality of milled rice with increased cylinder speeds. Further study on the interaction between cylinder speed and feed screw pitch is recommended. 5. An increase in the counter pressure level produced a negative effect On the head rice recovery with an increase in radial pressure, capacity, and machine efficiency over all combinations and at every level of cylinder speed. 6. Head rice recovery rates were conditioned primarily by the pressure inside the whitening chamber. According to the empirical cha racteristics curve developed in this study, the relationships of head rice recovery ($Y_h$) and machine capacity ($Y_c$/TEX>) to internal radial pressure ($X_p$) followed an inverse quadratic function and a linear function respectively: $$Y_h^\Delta=\frac{1}{{1.4383-0.2951X_p^\ast+0.1425X_p^{\ast\ast}}^2} , (R^2=0.98)$$ $$Y_c^\Delta=-305.83+374.37X_p^{\ast\ast}, (R^2=0.88)$$ The correlation between capacity and power consumption per unit of brown rice expressed in the following exponential function: $$Y_c^\Delta=1.63Y_c^{-0.7786^\{\ast\ast}, (R^2=0.94)$$ These relationships indicate that when radial pressure increases above a certain range (1. 6 to 2.0 kg/$cm^2$ based On the results of the experiment) head ricerecovery decrea\ulcornerses in a quadratic relation with a inear increase in capacity but without any decrease in power consump tion per unit of brown rice. On the other hand, if radial pressure is below the range shown above, power consumption increases dramatically with a lin\ulcornerear decrease in capacity but without significant increases in head rice recovery. During the operation of a given whitening machine, the optimum radial pressure range or the correct capacity range should be selected by controlling the feed rate and/or counter-pressure keeping in mind the condition of the grain, particulary the hardness. It was observed that the total number of passes is related to radial pessure level, feed rate and counter-pressure level. The higher theradial pressure the fewer num\ulcornerber of pass required but with decreased head rice recovery. In particular, when using high feed rates, the total number of passes should be increased to more than three by reducing the counter-pressure level to avoid decreaseases in head rice recovery (less than 65 percent head rice recovery on the basis of brown rice) at every cylinder speed. 7. A rapid rise in grain temperature seemed to have a close relationship with the pressure generated inside the whitening chamber and, subsequently with head rice reco\ulcornervery rates. The higher the rate of increase, the lower were the resulting head rice recoveries.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.162-169
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• 2000

This study was carried out to develop a continuously variable-speed transmission(CVT) for agricultural tractor. A full-toroidal CVT mechanism with four discs and six rollers was selected as a device for changing speed ratio continuously. In the step of system layout design, the sizes of roller cylinders and end-load cylinder, which were critical factors for controlling the variator, were designed. Also the control pressure range was designed to limit the contact pressure of variator. In order to make the maximum speed of vehicle as 30km/h, the planetary gear and the six pairs of gears were designed. Also the hydraulic clutch, silent chain, hydraulic manifold and electronic controller were designed. After the design, a prototype with CVT controller was developed and tested. The speed of vehicle was changed continuously to the speed set by driver and the settling time was about 0.52 second at the step-response test (reduction ratio of variator 2.0 to 1.0), which was acceptable as a response time for working with tractor.

• Journal of Chest Surgery
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• v.23 no.5
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• pp.864-870
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• 1990

This study was undertaken to evaluate current technique of extracorporeal circulation by analyzing the results in 73 cases. We performed standard cardiopulmonary bypass using Polystan roller pump, bubble[Polystan] and membrane[Cobe] oxygenator. There were 42 males and 31 females. We studied the changes of hemoglobin. hemodynamics, speed of cooling and warming, methods of cannulation and ACT. Arterial cannula was inserted on ascending aorta except for 7 cases of femoral cannulation. Preoperative hemoglobin was 13.2 gm% and this value dropped to 7.5 gm% during perfusion. Blood pressure of 113 mmHg in systolic dropped 57mmHg in 10 minutes of perfusion and became 98 mmHg at the end of perfusion. Initial drop of blood pressure was marked in pediatric patient. Mean cooling time was 19.4 min[0.54 Q /min] and warming time was 34 minutes[0.25 Q /min]. During perfusion, ACT was maintained above 600 sec and 44 patient did not need additional Heparin.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.11
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• pp.885-890
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• 2015

Nanomaterials possess unique mechanical, physical, and chemical properties. They are small, and have an ultrahigh surface area, making them suitable for air filter applications. Electrospinning has been recognized as an efficient technique for fabricating polymer nanofibers. In order to determine the optimum manufacturing conditions, the effects of several electrospinning process parameters on the diameter, orientation, and distribution of polyacrylonitrile (PAN) nanofiber are analyzed. To improve interlaminar fracture toughness and suppress delamination in the form of laminated non-woven fibers by using a heat roller, the performances of filter efficiency and pressure drop achieved with PAN nanofiber air filter are evaluated experimentally.