• 근관절건강학회지
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• 제15권1호
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• pp.53-61
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• 2008

Purpose: The purpose of this study was to observe the changes of the pain, fatigue, perceived health status, disability in ADL, and depression after Tai Chi for arthritis. Method: The subjects were 19 osteoarthritis women enrolled at one primary health care post. They have agreed to participate in this study, and participated in the 12-week Tai Chi program from Dec. 2006 to Mar. 2007, and all the measurement processes in right after, 2 months later, and 4 months later after Tai Chi program. The measurement tools of this study were all self-reported questionnaires such as Numerical Rating Scale (0-100) for pain, fatigue, and perceived health status, Korean-WOMAC (Western Ontario and McMaster University Osteoarthritis) Index for joint stiffness, Korean Health Assessment Questionnaire, and CES-Depression scale. Results: The repeated measure ANOVA revealed the significant differences on pain among the right after, 2 months later, and 4 months later the program. Especially 2 months later after program, pain was significantly increased than right after by t-test. There were no significant differences on fatigue, perceived health status, disability in ADL, and depression. Conclusion: Pain was increased after Tai Chi for arthritis program, but fatigue, perceived health status, disability in ADL, and depression were not changed until 4 months after Tai Chi program.

• 한국식품조리과학회지
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• 제10권3호
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• pp.301-307
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• 1994

Benzo(a)pyrene [B(a)P], one of the polycyclic aromatic hydrocarbons(PAHs) is know as a potent careinogen. As consumption of lipid food and fried food increases recently, the toxic effect of overheated lipid foods has report increasingly. This study was undertaken to measure the contents of B(a)P and other PAHs of fried chicken and frying oil. At the same time, the rancidities of frying oil and descarded oil were determined. B(a)P and other PAHs contents of all samples were measured by HPLC/UV method. The results obtained were as follows; B(a)P contents of fresh chicken and soybean oil were 0.073 and 0.146 ${\mu}$g/kg, respectively. During fried chicken at 180${\pm}$5$^{\circ}C$ and 200${\pm}$5$^{\circ}C$, B(a)P and PAHs contens decreased or increased In 20 times fried chicken, PAHs contents except Pyr and DMBA increased at 180${\pm}$5$^{\circ}C$ and PAHs contents except DMBA, DBA, and 3-MC increased at 200${\pm}$5$^{\circ}C$. In frying oils fried chicken, PAHs contents increased in 10 and 15 times frying oil at 180${\pm}$5$^{\circ}C$ and grew more increase and more increase during frying at 200${\pm}$5$^{\circ}C$. The changing pattern of PAHs contents of frying oils was remotely related that of rancidities of frying oils. In fried chicken, frying oils, and discarded oils obtained from fried chicken house at market, PAHs contents of fried chickens were lower than those of fried chicken cooked at laboratory but those of frying oils and discarded oils were higher than those of frying oils cooked at laboratory.

• 한국표면공학회지
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• 제39권1호
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• pp.25-34
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• 2006

Al-Mg alloy, an open rack vaporizer(ORV) material was reported to be corroded in seawater environments though the ORV material was coupled to thermally sprayed Al-Zn alloy functioning a sacrificial anode. In addition, the corrosion behavior based on the calculated corrosion potential did not match the observed corrosion behavior. Hence, the goal of this study is to get better understanding on Al or Al-Mg alloy coupled to Al-Zn alloy and to provide the calculated corrosion potential representing the corrosion behavior of the ORV material by immersion test, electrochemical tests, and calculation of corrosion and galvanic potential. The corrosion potentials of Al and Al alloys also depended on alloying element as well as surface defects. The corrosion potentials of Al and Al-Mg alloy were changed with time. In the meantime, the corrosion potentials of Al-Zn alloys were not. The corrosion rates of Al-Zn alloys were exponentially increased with zinc contents. The phenomena were explained with the stability of passive film proved by passive current density depending on pH and confirmed by the model proposed by McCafferty. Dissimilar material crevice corrosion (DMCC) test shows that higher content of zinc caused Al-Mg alloy corroded more rapidly, which was due to the fact that higher corrosion rate of Al-Zn makes [$H^+$] and [$Cl^-$] more concentrated within pit solution to corrode Al-Mg alloy. Considering electrochemical reactions within pit as well as bulk in the calculation gives better prediction on the corrosion behavior of Al and Al-Mg alloy as well as the capability of Al-Zn alloy for corrosion protection.

• Advances in aircraft and spacecraft science
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• 제5권3호
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• pp.363-383
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• 2018

One-dimensional (1D) models of incompressible flows, can be of interest for many applications in which fast resolution times are demanded, such as fluid-structure interaction of flows in compliant pipes and hemodynamics. This work proposes a higher-order 1D theory for the flow-field analysis of incompressible, laminar, and viscous fluids in rigid pipes. This methodology is developed in the domain of the Carrera Unified Formulation (CUF), which was first employed in structural mechanics. In the framework of 1D modelling, CUF allows to express the primary variables (i.e., velocity and pressure fields in the case of incompressible flows) as arbitrary expansions of the generalized unknowns, which are functions of the 1D computational domain coordinate. As a consequence, the governing equations can be expressed in terms of fundamental nuclei, which are invariant of the theory approximation order. Several numerical examples are considered for validating this novel methodology, including simple Poiseuille flows in circular pipes and more complex velocity/pressure profiles of Stokes fluids into non-conventional computational domains. The attention is mainly focused on the use of hierarchical McLaurin polynomials as well as piece-wise nonlocal Lagrange expansions of the generalized unknowns across the pipe section. The preliminary results show the great advantages in terms of computational costs of the proposed method. Furthermore, they provide enough confidence for future extensions to more complex fluid-dynamics problems and fluid-structure interaction analysis.

• Advances in aircraft and spacecraft science
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• 제7권3호
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• pp.229-249
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• 2020

This paper is the logical follow-up of four papers by the author on the subject "aerodynamics in Mars atmosphere". The aim of the papers was to evaluate the influence of two Mars atmosphere models (NASA Glenn and GRAM-2001) on aerodynamics of a capsule (Pathfinder) entering the Mars atmosphere and also to verify the feasibility of evaluating experimentally the ambient density and the ambient pressure by means of the methods by McLaughlin and Cassanto respectively, therefore to correct the values provided by the models. The study was carried out computationally by means of: i) a code integrating the equations of dynamics of an entry capsule for the computation of the trajectories, ii) two Direct Simulation Monte Carlo (DSMC) codes for the solution of the 2-D, axial-symmetric and 3-D flow fields around the capsule in the altitude interval 50-100 km. The computations verified that the entry trajectories of Pathfinder from the two models, in terms of the Mach, Reynolds and Knudsen numbers, were very different. The aim of the present paper is to continue this study, considering other aerodynamic problems and then to provide a contribution to a long series of papers on the subject "aerodynamics in Mars atmosphere". More specifically, the present paper evaluated and quantified the effects from the two models of: i) chemical reactions on aerodynamic quantities in the shock layer, ii) surface temperature, therefore of the contribution of the re-emitted molecules, on local (pressure, skin friction, etc.) and on global (drag) quantities, iii) surface recombination reactions (catalyticity) on heat flux. The results verified that the models heavily influence the flow field (as per the shock wave structure) but, apart from the surface recombination reactions, the effects of the different conditions on aerodynamics of the capsule are negligible for both models and confirmed what already found in the previous paper that, because of the higher values of density from the NASA Glenn model, the effects on aerodynamics of a entry capsule are stronger than those computed by the GRAM-2001 model.

• Smart Structures and Systems
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• 제15권1호
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• pp.135-150
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• 2015

Large concrete structures are prone to cracks and damages over time from human usage, weathers, and other environmental attacks such as flood, earthquakes, and hurricanes. The health of the concrete structures should be monitored regularly to ensure safety. A reliable method of real time communications can facilitate more frequent structural health monitoring (SHM) updates from hard to reach positions, enabling crack detections of embedded concrete structures as they occur to avoid catastrophic failures. By implementing an unconventional mode of communication that utilizes guided stress waves traveling along the concrete structure itself, we may be able to free structural health monitoring from costly (re-)installation of communication wires. In stress-wave communications, piezoelectric transducers can act as actuators and sensors to send and receive modulated signals carrying concrete status information. The new generation of lead zirconate titanate (PZT) based smart aggregates cause multipath propagation in the homogeneous concrete channel, which presents both an opportunity and a challenge for multiple sensors communication. We propose a time reversal based pulse position modulation (TR-PPM) communication for stress wave communication within the concrete structure to combat multipath channel dispersion. Experimental results demonstrate successful transmission and recovery of TR-PPM using stress waves. Compared with PPM, we can achieve higher data rate and longer link distance via TR-PPM. Furthermore, TR-PPM remains effective under low signal-to-noise (SNR) ratio. This work also lays the foundation for implementing multiple-input multiple-output (MIMO) stress wave communication networks in concrete channels.

• Hip & pelvis
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• 제30권4호
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• pp.260-268
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• 2018

Purpose: This study was performed to assess the clinical and radiological outcomes following one-stage hip reconstruction, consisting of open reduction femoral shortening and pelvic osteotomy, for neglected developmental dislocation of the hip (DDH). Materials and Methods: This is a retrospective analysis of 77 hips in 65 patients (46 females and 19 males; 12 had bilateral dislocations), operated at a Ghurki Trust Teaching Hospital in Pakistan between 2013 and 2015. The average age at surgery was $11.02{\pm}3.43$ years. According to the Tonnis classification, there were 10, 14, 22, and 31 patients in grades 1, 2, 3, and 4, respectively. The pelvic procedure utilized in this study was triple osteotomy (47 hips) followed by double and Salter osteotomy (18 and 12 hips, respectively). Postoperative evaluations were conducted using the modified MacKay's scoring system (functional outcomes) and Severin's scoring method (radiological assessment). Results: Postoperatively, there were 38 (49.4%), 19 (24.7%), 14 (18.2%), and 6 (7.8%) hips in Severin grade I, II, III and IV, respectively. According to the modified McKay criteria, there were 22 hips (28.6%) in excellent condition, 44 (57.1%) in good condition, 9 (11.7%) in fair condition and 2 (2.6%) in poor condition. Both patients with poor outcomes had an unstable, painful hip with evidence of avascular necrosis of the femoral head. Conclusion: Based on the results presented here, we recommend the single stage procedure of open reduction, femoral shortening and pelvic osteotomy for treatment of DDH in older children with good to excellent functional and radiological outcomes.

• 한국농공학회논문집
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• 제61권2호
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• pp.41-50
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• 2019

Stiffness characteristic of subgrade is one of the most important aspects for the design and evaluation of pavement and railway. However, adequate field testing methods for evaluating the stiffness characteristics of the subgrade have not been developed yet. In this study, an in-situ dynamic stiffness analyzer (IDSA) is developed to evaluate the characteristics of subgrade stiffness along the depth, and its performance is evaluated in elastic materials and a compacted soil. The IDSA consists of a falling hammer system, a connecting rod, and a tip module. Four strain gauges and an accelerometer are installed at the tip of the rod to analyze the dynamic response of the tip generated by the drop of hammer. Based on the Boussinesq's method, the stiffness and Young's modulus of the specimens can be calculated. The performance of IDSA was tested on three elastic materials with different hardness and a compacted soil. For the repeatability of test performance, the dynamic signals for force and displacement of the tip are averaged from the hammer impact tests performed five times at the same drop height. The experimental results show that the peak force, peak displacement, and the duration depend on the hardness of the elastic materials. After calculating the stiffness and elastic modulus, it is revealed that as the drop height of hammer increases, the stiffness and elastic moduli of MC nylon and the compacted soil rapidly increase, while those of urethanes less increase.

• Physical Therapy Rehabilitation Science
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• 제8권1호
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• pp.22-31
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• 2019

Objective: For knee osteoarthritis (OA), there is a demand for alternative modalities in order to delay surgery and to avoid the side effects of medications. This study compared the effects of applying seaweed pack and mudpack for the treatment of knee OA. Design: Randomized controlled trial. Methods: Twenty-five patients with knee OA who satisfied the criteria were included. The patients were divided into two groups according to the treatment method: mudpack (n=12) and seaweed pack (n=13). The two groups were treated for 20 minutes, twice a day for five continuous days at the Ocean Healing Center at Wando Island, South Korea. Participants were assessed by clinical scores (Western Ontario and McMaster Universities Osteoarthritis Index, Hospital for Special Surgery Knee Score, Knee injury and Osteoarthritis Outcome Score and 36-Item Short Form Health Survey) and lab results (erythrocyte sedimentation rate, C-reactive protein, insulin-like growth factor-1 [IGF-1], tumor necrosis $factor-{\alpha}$ [$TNF-{\alpha}$]) during the follow-up period. Results: For the most part, clinical scores improved after therapy and maintained improvements for four weeks in both groups (p<0.05). In the seaweed group, $TNF-{\alpha}$ was significantly decreased at two weeks post-therapy (p<0.05). In both groups, IGF-1 was significantly increased immediately post-therapy (p<0.05). There were no statistically significant differences after therapy between the groups in clinical scores and labs. Conclusions: Seaweed packs and mudpacks had similar positive effects for knee OA. Additionally, the seaweed pack group showed decreased levels of $TNF-{\alpha}$ at two weeks post-treatment, which may explain the reduced inflammatory reaction. For rehabilitation therapy, use of seaweed packs may serve as an alternative modality for the treatment of knee OA.

• Korean journal of medical education
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• 제30권4호
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• pp.295-308
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• 2018

Purpose: Although medical curricula are now better structured for integration of biomedical sciences and clinical training, most teaching and learning activities still follow the older teacher-centric discipline-specific formats. A newer pedagogical approach, known as Collaborative Learning Cases (CLCs), was adopted in the medical school to facilitate integration and collaborative learning. Before incorporating CLCs into the curriculum of year 1 students, two pilot runs using the action research method was carried out to improve the design of CLCs. Methods: We employed the four-phase Kemmis and McTaggart's action research spiral in two cycles to improve the design of CLCs. A class of 300 first-year medical students (for both cycles), 11 tutors (first cycle), and 16 tutors (second cycle) were involved in this research. Data was collected using the 5-points Likert scale survey, open-ended questionnaire, and observation. Results: From the data collected, we learned that more effort was required to train the tutors to understand the principles of CLCs and their role in the CLCs sessions. Although action research enables the faculty to improve the design of CLCs, finding the right technology tools to support collaboration and enhance learning during the CLCs remains a challenge. Conclusion: The two cycles of action research was effective in helping us design a better learning environment during the CLCs by clarifying tutors' roles, improving group and time management, and meaningful use of technology.