• Title/Summary/Keyword: Physical Parameter

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Effect of Change in Degrees of Inclination during Treadmill Gait Training on EEG of Stroke Patients (경사도 각도에 따른 트레드밀 보행훈련 시 뇌졸중 환자의 뇌파에 미치는 영향)

  • Sun-Min Kim;Dong-Hoon Kim;Sang-Hun Jang
    • PNF and Movement
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    • v.22 no.1
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    • pp.139-149
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    • 2024
  • Purpose: This study aimed to investigate the effects of gradually increasing treadmill inclination on the electroencephalogram (EEG) of stroke patients during gait training. Methods: Three stroke patients who were diagnosed with stroke within six months and capable of walking on a treadmill were selected as subjects. EEG electrodes were attached at Fp1, Fp2, F3, F4, C3, C4, P3, and P4 positions of the cerebral hemispheres using the International 10-20 system. The intervention involved walking for 2 minutes each at 0 degrees, 15 degrees, and 30 degrees inclination on the treadmill while focusing on a target point located in front during the treadmill gait training. The EEG (Smartingmobi, Serbia) generated when the treadmill gradient gradually increased was measured. In addition, relative alpha and relative beta waves were visualized through the Brain mapping program in the TeleScan program to assess the changes in each brain region for the activity of the EEG. Results: The relative alpha wave value decreased as treadmill inclination increased, while the relative beta wave value increased. Conclusion: Gradually increasing the inclination during treadmill gait training appears to be a crucial parameter for increasing the brain activity levels of stroke patients.

Reactive Extraction of Organic Acid with Amine Extractant, I. (A Study on the Effects of Extractant and Solvent on the Degree of Extraction in Reactive Extraction of Organic Acid) (아민 추출제에 의한 유기산의 반응추출(I) (유기산의 반응추출시 추출도에 미치는 추출제 및 용매의 영향에 관한 연구))

  • Ryu, Oon-Hyung;Lee, Han-Seob;Yoo, Chul-Hwi;Kim, Yong-Yeul;Kang, An-Soo
    • Applied Chemistry for Engineering
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    • v.7 no.1
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    • pp.203-213
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    • 1996
  • In physical and reactive extraction system using equilibrium extraction equipment, the effects of extractants, concentration of extractant, and solvent on the degree of extraction were investigated. The organic acids used were acrylic acid and metacrylic acid. Extractants were n-octylamine(OA), di-n-octylamine(DOA), tri-n-octylamine(TOA) and tri-octylmetyl ammonium chloride(TOMAC ; Aliquat 336). We found that the degree of extraction for reactive extraction was 2~9 times than that for physical extraction and that effect of extractants on the degree of extraction of organic acid was the order of OA

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Effects of Neck and Shoulder Exercise Program on Spino-Pelvic Alignment in Subject with Forward Head Posture (목과 어깨근육 운동프로그램이 전방머리자세의 척추-골반 정렬 변화에 미치는 영향)

  • Kang, Hyojeong;Yang, Hoesong
    • Journal of The Korean Society of Integrative Medicine
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    • v.7 no.4
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    • pp.265-272
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    • 2019
  • Purpose : Excessive computer use frequently results in musculoskeletal disorders of the neck and shoulder such as forward head posture (FHP). The purpose of this study was to investigate effects of neck and shoulder exercise program on spino-pelvic alignment and the correlation between change in head and neck posture and spino-pelvic alignment in FHP. Methods : The study included 44 participants with FHP. The participants performed the exercise for correction of FHP 2-3 times a week for 4 weeks. We examined whole spine X-ray images in the lateral standing position with both arms crossed. We measured anterior head translation distance (AHT), craniovertebral angle (CVA), cervical lordosis (CL), thoracic kyphosis (TK), lumbosacral lordosis (LSL), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI) of the subjects. The association between change in AHT and each spino-pelvic parameter was also subjected to Pearson's correlation coefficient analysis. Results : There were statistically significant differences before and after exercise in the parameters of AHT, CVA, and SS (p<.05). Significant negative correlation was observed between the change in AHT and CVA (r=-.768, p<.001), and CL (r=-.388, p<.05). There was significant positive correlation between the change in AHT and SS (r=.328, p<.05), and PI (r=.333, p<.05). However, no significant correlation was observed in change in AHT with that of TK, LSL, and PT. Conclusion : Based on the above results, we conclude that there is a relationship between change in AHT, which is a parameter associated with forward displacement of the head, and that of CVA, CL, SS, and PI after exercise in cases of FHP.

A Study on the Application of the National CIS and Environmental Observation Data for Assessment of Regional Water Balance: A Case of the Catchment of Guryang Stream (지역 물수지 평가를 위한 NGIS와 환경 관측 자료의 활용에 관한 연구 -구량천 유역을 사례로-)

  • Park, Jong-Chul
    • Journal of the Korean Geographical Society
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    • v.44 no.4
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    • pp.557-576
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    • 2009
  • Physical based water balance model had better simulation results than conceptial model, however it is difficult to obtain input data for the model. This study suggests some methods to obtain parameter values of BROOK90 from meteorological data, soil map, land-use map. Comparing measured and simulated discharge proved the methods to be valid. For validation model($2001{\sim}2003$), comparing measured and simulated discharge a daily mean bias error, Nash-Sutcliffe's model efficiency coefficient, coefficient of determination equal to -0.517, 0.87 and 0.89 respectively. The results of this study would be helpful to the hydrological study using physical based hydrological model not only in super site but in other catchments.

Partitioning Behavior of Selected Printing Ink Solvents between Headspace and Chocolate Cookie Samples

  • An, Duek-Jun
    • Preventive Nutrition and Food Science
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    • v.16 no.3
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    • pp.267-271
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    • 2011
  • Static Headspace Gas Chromatographic analysis was used to study the partitioning behavior of five organic printing ink solvents between chocolate cookie/air systems. Three cookie sample formulations varied with respect to chocolate type and overall percentage of constituents. Major considerations involved differences in fat content and type and resulting variability in chemical and physical structure. Each of the solvents studied (ethyl acetate, hexane, isopropanol, methyl ethyl ketone, toluene) represents a general class of printing ink solvents based on predominate functional group. Values of the partitioning coefficient (Kp) were determined at equilibrium using measured quantities of both solvent and cookie sample in closed systems at temperature of 25, 35, and $45^{\circ}C$. In each of the three cookies at the three test temperatures, toluene always exhibited the greatest value of partitioning to cookie and hexane always exhibited the least. Results also showed that the partitioning behavior of solvents is generally inversely related to temperature and that solvent affinity, though constant for a particular cookie type over all test temperatures, varies significantly among the three cookie types. The preference of each of the five solvents for each cookie sample was also found to vary with temperature. No correlation was found between the extent of partitioning and cookie formulation or physical characteristic of solvent. The Hildebrand parameter, related to ${\Delta}Hmix$ (heat of mixing), may be used to describe differences in partitioning based on the overall potential of a solvent/cookie interaction to occur. The potential for interaction is dependent upon the chemical structure of the cookie sample and thus the availability of 'active-sites' required for a given solvent.

Evaluation of constitutive relations for concrete modeling based on an incremental theory of elastic strain-hardening plasticity

  • Kral, Petr;Hradil, Petr;Kala, Jiri
    • Computers and Concrete
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    • v.22 no.2
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    • pp.227-237
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    • 2018
  • Today, the modeling of concrete as a material within finite element simulations is predominantly done through nonlinear material models of concrete. In current sophisticated computational systems, there are a number of complex concrete material models which are based on theory of plasticity, damage mechanics, linear or nonlinear fracture mechanics or combinations of those theories. These models often include very complex constitutive relations which are suitable for the modeling of practically any continuum mechanics tasks. However, the usability of these models is very often limited by their parameters, whose values must be defined for the proper realization of appropriate constitutive relations. Determination of the material parameter values is very complicated in most material models. This is mainly due to the non-physical nature of most parameters, and also the large number of them that are frequently involved. In such cases, the designer cannot make practical use of the models without having to employ the complex inverse parameter identification process. In continuum mechanics, however, there are also constitutive relations that require the definition of a relatively small number of parameters which are predominantly of a physical nature and which describe the behavior of concrete very well within a particular task. This paper presents an example of such constitutive relations which have the potential for implementation and application in finite element systems. Specifically, constitutive relations for modeling the plane stress state of concrete are presented and subsequently tested and evaluated in this paper. The relations are based on the incremental theory of elastic strain-hardening plasticity in which a non-associated flow rule is used. The calculation result for the case of concrete under uniaxial compression is compared with the experimental data for the purpose of the validation of the constitutive relations used.

A Study on the Analysis of the Slope Stability Considering Clay Filling in Discontinuity (불연속면내 점토충전물을 고려한 사면 안정해석 연구)

  • Min, Kyong-Nam;Ahn, Tae-Bong;Yang, Seung-Jun;Baek, Seon-Gi;Lee, Tae-Sun
    • Tunnel and Underground Space
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    • v.17 no.3 s.68
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    • pp.175-185
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    • 2007
  • When filling material such as clay is included along the discontinuity, it may cause instability on a slope even if the direction of discontinuity works in a positive way. In the study area, slope sliding occurred at the boundary between a clay filling material and weathered soil because the physical properties differ across the boundary; and this is very similar to the situation where foliation in a rock works as a weak zone during a structural behavior, causing an inter-layer slip. In most analysis, if there exists a clay filling material, a single discontinuity is assumed to perform analysis. In those cases, the discontinuity is modeled as a slip surface within clay. Therefore, the characteristics of the boundary are not considered in the analysis, so that ultimately the physical property of clay usually prevails. The result of evaluating the slope stability affected by clay filling material shows the significant difference in the safety level due to the strength parameter depending on the failure type of the discontinuity by a filling material.

A Quantitative Physical Parameter for Detection of Ultimate Failure State of Soil Using CEL Method in Finite Element Analysis (CEL 기법을 이용한 유한 요소 해석에서 지반의 극한 파괴 상태 감지를 위한 정량적 물리량 기준)

  • Kim, Seongmin;Lee, Ju-Hyung;Jung, Young-Hoon
    • Journal of the Korean Geotechnical Society
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    • v.34 no.12
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    • pp.59-69
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    • 2018
  • In order to use the limit equilibrium theory, it is necessary to find a slip line under the ultimate failure condition. The strength reduction method using the Lagrangian finite element method defines the ultimate failure state at a time when the numerical solution cannot converge within the certain number of the iteration. When the coupled Eulerian-Lagrangian (CEL) method is used, however, such definition is inappropriate because the numerical solution of the CEL method can converge even under the ultimate failure condition. In this study, an objective condition designating the ultimate failure state in the finite element analysis adopting the CEL method was proposed. In the problem of the bearing capacity of the undrained soft ground subjected to the strip footing loading, we found that the rate of the plastic dissipated energy is highly sensitive at the load of the theoretical limit of the ultimate failure state.

A Correction Effect of Multiaxial Lower Extremity Orthosis in Patients with Genu Valgum (다 축면 하지 보조기가 외반슬 교정에 미주는 효과)

  • Chang In-Su;Bae Sung-Soo
    • The Journal of Korean Physical Therapy
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    • v.14 no.3
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    • pp.355-372
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    • 2002
  • The purpose of this study was to evaluate the effect of multiaxial lower extremity orthosis on correction of genu valgum. 20 volunteers among people visited department of Rehabilitation Medicine, chungnam national university hospital, who had been diagnosed as genu valgum without other musculoskeletal problems were included. 10 individuals(mean age: 9.gyrs) who had been taken multiaxial lower extremity orthosis at least 12month were included in experimental group and the other 10 individuals(mean age: 11.7yrs) refused taking this orthosis in the control group. We measured the Q-angle & femorotibial angle using plain roentgenogram images at visiting day and repeat same test after 1year follow up. Multiaxial lower extremity orthosis consist of proximal horizontal bar with both thigh cuff, central vertical bar and distal horizontal bar with both shoes. we narrowed inter-shoes distance from start to 6th month and inter-thigh cuff distance together with above correction for next 6month in the frontal plane and from 10th month, dorsiflexed both shoes in sagittal plane. Also, we rotate the both shoes externally and retract the proximal vertical bar every month. This orthosis have to be taken at least 4 hours during sleep. The result were as follows 1. There were no statistical significant difference in each parameter between the right and left Q-angle before multiaxial lower extremity orthosis. 2. The left Q angle reduced $-11^{\circ}$ between 1st day and after 1year follow up showed statistical significant difference between multiaxial lower extremity orthosis taking group and non-taking(p<0.001). 3. The right Q angle reduced $-13^{\circ}$ between 1st day and after 1year follow up showed statistical significant difference between multiaxial lower extremity orthosis taking group and non-taking(p<0.001). 4. There were no statistical significant difference in each parameter between the right and left femorotibial angle before multiaxial lower extremity orthosis. 5. The left femorotibial angle reduced $-10.1^{\circ}$ between 1st day and after lyear follow up showed statistical significant difference between multiaxial lower extremity orthosis taking group and non-taking(p<0.001). 6. The right femorotibial angle reduced $-11.2^{\circ}$ between 1st day and after 1year follow up showed statistical significant difference between multiaxial lower extremity orthosis taking group and non-taking(p<0.001).

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The Relationships among Gait Asymmetry, the Gait Velocity and Motor Function of Lower Extremity in Stroke Patients (뇌졸중 환자의 보행 비대칭성과 속도, 하지 운동 기능과의 상관관계)

  • Nam, Hyoung-Chun;Kim, Seong-Yeol;An, Seung-Heon
    • Journal of the Korean Society of Physical Medicine
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    • v.5 no.3
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    • pp.385-394
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    • 2010
  • Purpose : The present study was to examine the difference and severity of asymmetry in independently ambulating stroke survivors and to establish the association between gait asymmetry, velocity, and the motor function of lower extremity. Methods : The subjects used in this study were 43 subjects with hemiparesis being able to walk independently. Motor function of lower extremity was measured clinically with the Fugl Meyer-Lower /Extremity Assessment. Overground gait velocity and spatia-temporal parameters were collected by the GAITRite system. Results : Thirty(69.77%) patients showed statistically significant temporal asymmetry while 28(65.1%) exhibited statistically significant spatial asymmetry. One-way ANOVA results showed a main effect of temporal asymmetry group(normative, mild, severe) for gait velocity(F=74.129), FM-L/E(F=17.270), swing-stance symmetry(F=66.869, F=13.485, respectively), spatio-temporal asymmetry(F=13.166, F=31.800, respectively) 66, F=31.800, respectively). Gait velocity was negatively associated with temporal asymmetry(r=-.83), spatial asymmetry(r=-.60). Motor function of lower extremity was also associated with temporal asymmetry(r=-.58), and spatial asymmetry(r=-.50). Conclusion : The study attempted to establish the standard assessment of hemiparesis gait symmetry in light of the complex relationship with motor impairment and gait velocity. More future work will need to link the degree of gait asymmetry to clinically relevant outcomes to better establish the clinical significance of such observations.