• Title/Summary/Keyword: Two-Time-Scale System

Search Result 434, Processing Time 0.026 seconds

LARGE EDDY SIMULATION OF ORDINARY & EMERGENCY VENTILATION FLOW IN UNDERGROUND SUBWAY STATION (지하역사 승강장 및 대합실 평상시 비상시 급·배기 환기 Large Eddy Simulation)

  • Jang, Yong-Jun;Ryu, Ji-Min;Park, Duck-Shin
    • Journal of computational fluids engineering
    • /
    • v.18 no.3
    • /
    • pp.72-78
    • /
    • 2013
  • The turbulent flow behavior of air supply and exhaustion in the Shin-gum-ho subway station is analyzed for ordinary and emergency state. The depth of Shin-gum-ho station is 43.6m which consists of the island-type platform(8th floor in underground) and a two-story lobby (first & second floor in underground). An emergency stairway connects between the platform and the lobby. Ventilation operation mode for ordinary state is set up as a combination of air supply and exhaustion in the lobby and platform, while for emergency state it is set up as a full air supply in the lobby and a full exhaustion in the platform. The entire station is covered for simulation. The ventilation diffusers are modeled as 95 square shapes of $0.6m{\times}0.6m$ in the lobby and as 222 square shapes of $0.6m{\times}0.6m$ and 4 rectangular shapes of $1.2m{\times}0.8m$ in the platform. The total of 7.5million grids are generated and whole domain is divided to 22 blocks for MPI efficiency of calculation. Large eddy simulation(LES) is applied to solve the momentum equation and Smagorinsky model($C_s$=0.2) is used as SGS(subgrid scale) model. The time-averaged velocity fields are compared to experimental data and show a good agreement with it.

Characteristics of Liquid-Liquid Direct Contact Heat Exchanger for a Solar System (태양열 이용을 위한 직접접촉식 액-액 열교환기 특성)

  • 강인석;김종보;강용혁;곽희열
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.18 no.12
    • /
    • pp.3276-3286
    • /
    • 1994
  • In most direct contact liquid-liquid heat exchangers, oil or hydrocarbon with a density less than water is normally used as dispersed working fluid. The main difficulty that arises with this arrangement lies in the control of the interface at the top of the column. When it is connected with a solar collector which uses water as its working fluid, the main difficulties arise from the fact that the water can be frozen during winter time. In order to solve these problems and to demonstrate the technical feasibility of a direct contact liquid-liquid heat exchanger, liquids heavier than water with low freezing temperature has been utilized as dispersed phase liquids in a small laboratory scale model made of pyrex glass. In the present investigation, dimethyl phthalate(C/sub 6/H/sub 4/)COOCH/sub 3/)/sub 2/) and diethyl phthalate (C/sub 6/H/sub 4/(CO/sub 2/C/sub 2/H/sub 5/)/sub 2/) are utilized as heavy dispersed phase working fluids. The results of the present investigation the technical in the utilization of heavier dispersed working liquid in the spray-column liquid-liquid heat exchanger for a solar system. The overall average temperature difference along the column is found to be almost half of the initial temperature difference between the dispersed and the continuous phase. Despite the fact that the two phthalates tested in the experiment differ significantly in some of their physical properties, the volumetric heat transfer coefficients in terms of dispersed fluid superficial velocities were found to be similar for both phthalates tested.

The efficient data-driven solution to nonlinear continuum thermo-mechanics behavior of structural concrete panel reinforced by nanocomposites: Development of building construction in engineering

  • Hengbin Zheng;Wenjun Dai;Zeyu Wang;Adham E. Ragab
    • Advances in nano research
    • /
    • v.16 no.3
    • /
    • pp.231-249
    • /
    • 2024
  • When the amplitude of the vibrations is equivalent to that clearance, the vibrations for small amplitudes will really be significantly nonlinear. Nonlinearities will not be significant for amplitudes that are rather modest. Finally, nonlinearities will become crucial once again for big amplitudes. Therefore, the concrete panel system may experience a big amplitude in this work as a result of the high temperature. Based on the 3D modeling of the shell theory, the current work shows the influences of the von Kármán strain-displacement kinematic nonlinearity on the constitutive laws of the structure. The system's governing Equations in the nonlinear form are solved using Kronecker and Hadamard products, the discretization of Equations on the space domain, and Duffing-type Equations. Thermo-elasticity Equations. are used to represent the system's temperature. The harmonic solution technique for the displacement domain and the multiple-scale approach for the time domain are both covered in the section on solution procedures for solving nonlinear Equations. An effective data-driven solution is often utilized to predict how different systems would behave. The number of hidden layers and the learning rate are two hyperparameters for the network that are often chosen manually when required. Additionally, the data-driven method is offered for addressing the nonlinear vibration issue in order to reduce the computing cost of the current study. The conclusions of the present study may be validated by contrasting them with those of data-driven solutions and other published articles. The findings show that certain physical and geometrical characteristics have a significant effect on the existing concrete panel structure's susceptibility to temperature change and GPL weight fraction. For building construction industries, several useful recommendations for improving the thermo-mechanics' behavior of structural concrete panels are presented.

A Comparative Study on the Perception of the Impediment Factors between Mothers and Nurses in Nursery (모유수유 저해요인에 대한 산모와 신생아실 간호사간의 인식정도 비교 연구)

  • Lee, Mi-Ja
    • Women's Health Nursing
    • /
    • v.1 no.1
    • /
    • pp.138-152
    • /
    • 1995
  • The condition of nutrition during infancy will greatly affect infants' physical, emotional growth, especially breast feeding is important in their growth and development, and emotional stability, too. Despite such advantages of breast-feeding, its rate has continued to fall year after year in Korea : the 95% rate in 1960's has fallen to 25.4% in 1990. It is known that such a downfall of breast-feeding rate is associated with various factors. The purpose of the study is to examine mother's and nurses' in nursery perception of the impediment factors of breast-feeding : to compare those between of breast-feeding : to compare those between two groups : to provide fundamental data for developing strategies for increasing breast-feeding. The subjects were 45 new mothers from one hospital and the same number of nurses sampled from 3 university hospitals, in Seoul. The data were collected for 11 days from April 12 to April 23, 1994 and a questionnaire was developed based on the interview with 14 nurses and 10 mothers and the literature reviews. Liker's Five-Point Scale was used as measurement. The Data were analyzed using SPSS / PC and descriptive statistics, t-test, ANOVA. The results of study are as follows : 1) Most new mothers get the information about breast-feeding from their mothers, books or newspaper, and relatives in rank than professionals(nurses or doctors). 2) The impediment factors the breast-feeding are categorized as mothers, hospital system, medical personnels and social factors. The most frequently mentioned impediment factors from mothers are 'Difficulty by operational wounds'(3.13), 'Lack of will for breast-feeding'(3.47), 'Insufficient rest and sleep'(3.52) and 'Opposition from husband or his family members'(4.77)in rank. On the other hand those factors from nurses are 'Inadequate nipple condition'(2.37), 'Decreasing milk secretion given medicine after operation'(2.63), 'Mothers knowledge deficit by poorly prepared education'(2.79) and 'Mothers abhorance of breast-feeing'(3.87) in rank. 3) As for the hospital system, the highly perceived impediment factors by mothers are 'Seperation of baby from mother after birth'(2.78), 'Lack of space for breast-feeding in the hospital'(2.93), 'Lack of facility for informing the time for breast-feeding'(3.18) and 'Because of babys' preference artificial nipple by being accustomed to it in hospital(3.97), in rank. Meanwhile, those from nurses are "Seperation of baby from mother after birth",(1.92), "Inconsistency between hospital's nursing time and mother's breast secretion time" scretion time(2.97), "Lack of space for breast-feeding in the hospital"(3.39), and "Lack of facility for informing the time for breast-feeding"(3.74) 4) As for the medical personnels, the highestly perceived Impediment factor from mothers in "Lack of professional nurses for breast-feeding"(2.96), and the lowestly perceived one is "Doctors' reluctance"(4.75). Nurses perceived same as mothers, too. 5) As for the social factors, the highestly perceived impediment factor by mothers and nurses is "Inconvience of social activities"(2.83) and the lowestly ones are "The sense of self-sacrifice"(4.22) by mothers, and "The sense of old fashioned"(4.13) by nurses. 6) The difference of the perception of impediment factors between mothers and nurses is statistically significant only in mother factor.

  • PDF

A Study on the Optimal Operation and Policy of the Boryeong Dam Diverion Pipe Line Using the SWAT Model (SWAT 모형을 이용한 보령댐 도수로 운영 방안 및 정책 연구)

  • Park, Bumsoo;Yoon, Hyo Jik;Hong, Yong Seok;Kim, Sung Pyo
    • Journal of Korean Society on Water Environment
    • /
    • v.36 no.6
    • /
    • pp.546-558
    • /
    • 2020
  • While industrialization has provided in abundance, the pollution it creates has caused untold damage to the environment, increasing the frequency and severity of natural disasters through changes in global climate patterns. The World Risk Forum's (WEF) World Risk Report presented the results of a survey of experts from around the world detailing the most influential risk factors over the next decade. Notably, the failure to respond to climate change ranked first and the global water crisis third. The extreme drought in the western Chungnam province was unexpected in 2016. At the time, the water level of Boryeong Dam was drastically decreased due to receiving less than half the average recorded rainfall in the region that year. The Boryeong Dam diversion pipeline has the capacity to solve the water shortage problem between these two regions by providing water from Geumgang to the western part of Chungnam, including Boryeong City. Current weather trends suggest drought is likely to continue in western Chungnam, which uses the Boryeong Dam as an intake source. This makes it necessary to operate Boryeong Dam diversion pipeline in an efficient and effective manner. SWAT is a watershed scale model developed to predict the impact of land management practices on water. The SWAT model was used in this study to evaluate the adequacy of the Boryeong Dam diversion pipeline operational plan by comparing it to present Boryeong Dam diversion pipeline operation. By investigating the number of days required to reach each reservoir stage, we determined that the number of days required to reach the boundary stage was less than that of the current operation. This determination accounts for the caveats that the Boryeong Dam waterway was not operated and only one pump will be operated from October to May of next year. As our results suggest, the most stable operation scenario is to operate two pumps at all times. This can be accomplished by operating two pumps from the caution stage to increase the number of pumps whenever the stage is raised. In addition to the stable operation of the Boryeong Dam pipeline, policy considerations are required with regard to imposing a water use charge on users of the Boryeong Dam region.

Open Treatment of Anterior Impingement Syndrome of the Ankle in Elite Level Soccer Players (축구 선수에서 발생한 족관절 전방 충돌 증후군의 개방적 수술의 치료 결과)

  • Lee, Kyung-Tai;Young, Ki-Won;Kim, J-Young;Kim, Eung-Soo;Cha, Seung-Do
    • Journal of Korean Foot and Ankle Society
    • /
    • v.8 no.1
    • /
    • pp.76-80
    • /
    • 2004
  • Purpose: We assessed the results of open treatment of anterior impingement syndrome of the ankle in elite level soccer players and concomitant injuries were idenfied. Materials and Methods: We retrospectively reviewed twenty one elite level soccer players diagnosed with anterior impingement syndrome who underwent open debridement between January 1997 and January 2002. All were men and the mean age at the operation was 21 years (range 16 to 27). The mean follow-up duration was 31 months (13 to 71). Concomitant abnormalities were idenfied through physical examination, bone scan and MRI. On a preoperative lateral radiograph, patients were classified according to McDermott's stage. Anteromedial or anterolateral approach was used at the operation and osteophyte was removed with osteotome and rongeur. When chronic ankle instability was accompanying, we performed Modified Brostrom-Gould procedure and for osteochondral lesion, multiple drilling was applied. The Ogilvie-Harris scoring system was used as a clinical scale to evaluate pain, swelling, stiffness and limitation of activity. The results were scored as excellent (15 to 16 points), good (13 to 14) and otherwise unsatisfactory. The time to return to full activity including sports activity was determined. Results: Eighteen of twenty one patients had an excellent outcome. Three patients were graded unsatisfactory and two of them abandoned their career due to the persistence of residual pain. Concomitant abnormalities were found including twelve cases of chronic ankle instability, three cases of osteochondral lesion and two cases of flexor hallucis longus tendinitis. Conclusion: Open debridement was successfully applied to the elite level soccer player with anterior impingement syndrome of the ankle. Considerable coexistence of other abnormalities such as chronic ankle instability may encourage us to consider additional operative procedure.

  • PDF

Open Versus Arthroscopic Technique in the Traumatic Recurrent Anterior Dislocation of the Shoulder (견관절 전방 재발성 탈구에 대한 관혈적 술식과 관절경적 술식의 결과 비교)

  • Kyung, Hee-Soo;Jeon, In-Ho;Kim, Sung-Jung;Yeo, Jun-Young
    • Clinics in Shoulder and Elbow
    • /
    • v.5 no.2
    • /
    • pp.110-117
    • /
    • 2002
  • Purpose: We compared the results of open and arthroscopic Bankart repair in traumatic recurrent anterior dislocation ,3f the shoulder. Materials and methods: We analysed 7 cases underwent open Bankart repair (group I) and 13 cases underwent arthroscopic Bankart repair (group Ⅱ). The average follow-up period was 68.1 months (51-113 months) in group I and 41.1 months (16~57 months) in group Ⅱ. All patients in group I and Ⅱ were non-athletes. We analyzed statistically objective evaluation, such as the stability of shoulder joint, the range of motion, pain, impaired throwing, Bankart rating system by Rowe and subjective evaluation, visual analog scale (VAS) between two groups. Results: In terms of dominant and non-dominant shoulders, the age at initial episode of dislocation, the elapsed time from injury to surgery, the number of preoperative dislocations associated with susceptibility to apprehension. respectively, there was no statistically significant differences between two groups. In group I the average Rowe's scortls was 84.3 and 3 cases (43%) had excellent results,4 cases (S7cfo), good ones. In group H the average Rowe's scores was 87.3 and 7 cases (54%) had excellent results,6 cases, good ones. There was tendency to show more excellent results in group ll, but there was no statistically significant differences. The average VAS were 90.3 points in group I and 88 points in group Ⅱ, which showed also no statistically significant differences. Conclusion: Open and arthroscopic Bankart repairs had no significant difference and showed also good results in travinatic recurrent anterior dislocation of shoulder.

Effect on Oriental-Western Medicine Intergrative Care after Gynecology Surgery (부인과 수술 후 한양방 협진 치료의 효과 연구)

  • Lee, Seung-Hwan;Lee, In-Seon;Cho, Hye-Sook;Kim, Kyu-Kon
    • The Journal of Korean Obstetrics and Gynecology
    • /
    • v.24 no.3
    • /
    • pp.127-145
    • /
    • 2011
  • Purpose: The purpose of this study is to analyze the effect of oriental-western medicine integrative care after gynecology surgery by DSOM((Diagnosis System of Oriental Medicine) and improvement of major symptoms. Methods: 66 patients belonged to the experimental group and 47 patients belonged to the control group out of 113 patients taken gynecology surgery. We studied general characteristics and difference on DSOM results between the two groups. And we had patients answer questionnaires about major symptoms such as abdominal discomfort, headache, fatigue, urinary discomfort, constipation, lumbago, edema, tingling, digestive disorder, cough, pruritus, arthralgia, cold feeling by VAS (Visual Analogue Scale) in order to analyze improvement and difference between two groups. Results: Experimental group had significantly high score on deficiency of blood, blood stasis, dryness, spleen, kidney, phlegm and high frequency on deficiency of blood, dampness, kidney, phlegm pathogenesis in DSOM. It had significantly high intensity in symptoms of abdominal discomfort, headache, fatigue, urinary discomfort, constipation, lumbago at the first time, and headache at 1 month after western hospital discharge out of symptoms associated with surgery. And it had significantly high improvement in symptoms of abdominal discomfort, headache, urinary discomfort, constipation at oriental-western integrative hospital discharge, and headache, fatigue, urinary discomfort, constipation, lumbago at 1 month after western hospital discharge out of symptoms associated with surgery. Conclusion: We recognized that oriental-western medicine integrative care after gynecology surgery has significant effect.

The effect of electronic commerce on the economy - logistics industry perspective - (전자상거래가 경제에 미치는 효과 - 물류 정보화를 중심으로 -)

  • 김범환
    • Proceedings of the Technology Innovation Conference
    • /
    • 1999.12a
    • /
    • pp.281-295
    • /
    • 1999
  • This paper analyses the effects of the increase of logistics outsourcing on the economy which are largely classified into three parts. The firm level and industry level are two among them which will be summarized below. The another is consumers level. On the fm level, the logistics outsourcing of a manufacturing firm not only helps to increase the efficiency of itself and but also confront the competitive environments by weakening the entry barriers, i.e., the emergence of contestable market. The reasons why the efficiency of the firm enhances are also largely divided into two parts. One is due to the reduction of inventory cost by replacing it by the information cost resulting from internet use. The other is owing to reducing the life cycle of production process by the emergence of virtual enterprises which are located in one point in De process of supply chain management. The weakening of entry barriers is directly affected by the drastic increase of internet users in twofold reasons: one is based on the restricted competitive characteristics due to the long-term transaction relationship between logistics providers and the companies who offer logistics services and the other, due to the weakening of the restriction of space and time. The effect of industry level is due to the transition of traditional to virtual vertical integration system The firms corresponding to a connection point in the process of supply chain management would try to realize both the scale of economy and the scope of economy for strengthening the competitiveness. We indicated above the emergence of contestable market however, it is a short-term phenomenon and result in the oligopoly market due to the entry barriers in the long-run sense.

  • PDF

Identification of New Source of Resistance to Powdery Mildew of Indian Mustard and Studying Its Inheritance

  • Nanjundan, Joghee;Manjunatha, Channappa;Radhamani, Jalli;Thakur, Ajay Kumar;Yadav, Rashmi;Kumar, Arun;Meena, Mohan Lal;Tyagi, Rishi Kumar;Yadava, Devender Kumar;Singh, Dhiraj
    • The Plant Pathology Journal
    • /
    • v.36 no.2
    • /
    • pp.111-120
    • /
    • 2020
  • Powdery mildew of Indian mustard (Brassica juncea), caused by Erysiphe cruciferarum, is emerging as major problem in India. All the Indian mustard cultivars presently grown in India are highly susceptible to powdery mildew and so far no resistance source has been reported. In this study, with an aim to identify resistant source, 1,020 Indian mustard accessions were evaluated against E. cruciferarum PMN isolate, at Wellington, The Nilgiris, Tamil Nadu, India under natural hot spot conditions. The study identified one accession (RDV 29) with complete resistance against E. cruciferarum PMN isolate for the first time, which was consistent in five independent evaluations. Genetic analysis of F1, F2 and backcross populations obtained from the cross RSEJ 775 (highly susceptible) × RDV 29 (highly resistant) for two season revealed that the resistance is governed by two genes with semi-dominant and gene dosage effect. Further, a new disease rating system using six scales (0, 1, 2, 3, 4, and 5) has also been proposed in this study to score powdery mildew based on progress of fungal growth in different plant parts of the F2 population. The outcome of this study viz. newly identified powdery mildew-resistant Indian mustard accession (RDV 29), information on inheritance of resistance and the newly developed disease rating scale will provide the base for development of powdery mildew-resistant cultivars of Indian mustard.