• Title/Summary/Keyword: Relaxation Procedures

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Evaluation of Thermal and Shrinkage Stresses in Hardening Concrete Considering Early-Age Creep Effect (초기재령 콘크리트의 크리프를 고려한 온도 및 수축응력 해석)

  • 차수원;오병환;이형준
    • Journal of the Korea Concrete Institute
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    • v.14 no.3
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    • pp.382-391
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    • 2002
  • This study is devoted to the problems of thermal and shrinkage stresses in order to avoid cracking at early ages. The early-age damage induced by volume change has great influence on the long-term structural performance of the concrete structures such as its durability and serviceability To solve this complex problem, the computer programs for analysis of thermal and shrinkage stresses were developed. In these procedures, numerous material models are needed and the realistic numerical models have been developed and validated by comparison with relevant experimental results in order to solve practical problems. A framework has been established for formulation of material models and analysis with 3-D finite element method. After the analysis of the temperature, moisture and degree of hydration field in hardening concrete structure, the stress development is determined by incremental structural formulation derived from the principle of virtual work. In this study, the stress development is related to thermal and shrinkage deformation, and resulting stress relaxation due to the effect of early-age creep. From the experimental and numerical results it is found that the early-age creep p)ays important role in evaluating the accurate stress state. The developed analysis program can be efficiently utilized as a useful tool to evaluate the thermal and shrinkage stresses and to find measures for avoiding detrimental cracking of concrete structures at early ages.

Anesthetic and Cardiopulmonary Effects of Butorphanol-Tiletamine-Zolazepam-Medetomidine and Tramadol-Tiletamine-Zolazepam-Medetomidine in Dogs (개에서 Butorphanol-Tiletamine-Zolazepam-Medetomidine과 Tramadol-Tiletamine-Zolazepam-Medetomidine 합제의 마취효과 및 심폐에 미치는 영향)

  • Nam, Seung-Wan;Shin, Beom-Jun;Jeong, Seong Mok
    • Journal of Veterinary Clinics
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    • v.30 no.6
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    • pp.421-427
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    • 2013
  • There are many intramuscularly injectable drugs commonly used for anesthesia in dogs and combination of drugs were used for decrease the side effects. The objective of this study was to evaluate the anesthetic and cardiopulmonary effects of butorphanol-tiletamine-zolazepam-medetomidine and tramadol-tiletamine-zolazepam-medetomidine in dogs. Ten healthy beagle dogs (intact male; mean body weight : $9.5{\pm}1.60$ kg) were used in the study. Experimental animals were divided into two groups (n=5, each) and received 0.2 mg/kg of butorphanol (BZM) and 2 mg/kg of tramadol (TZM) according to the group after injection of $Zoletil^{(R)}$ (5 mg/kg) and medetomidine (10 ug/kg). All drugs were administered intramuscularly. Anesthesia and recovery, sedation and analgesia score, cardiovascular and respiratory parameters were measured. Induction and recovery time were not significantly different between the groups. Anesthesia time was $117.4{\pm}25.64$ minute and $81.2{\pm}12.50$ minute in BZM and TZM groups, respectively. Sedation and analgesia were satisfied in both groups. In both groups, common side effects related to the medetomidine, significant bradycardia and hypertension were not observed. There were no significant changes in respiratory data. In conclusion, tiletamine-zolazepam-medetomidine in combination with either butorphanol or tramadol can be suitable anesthetic protocol for minor procedures in dogs. They produced adequate anesthesia characterized by rapid induction, adequate analgesia and muscle relaxation without remarkable side effects.