• Advances in concrete construction
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• 제10권3호
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• pp.221-236
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• 2020

To reduce the CO₂ emissions associated with the manufacture of portland cement (PC), an efficient alternative like an alkali-activated binder (AAB) is the requirement of the industry. To promote the use of AAB in construction activities, a practically implementable mix proportion is required. Owing to the several raw ingredients of AAB concrete and their associated uncertainties, partial replacement of PC by AAB may be adopted instead of complete replacement as per industrial requirements. Hence, the present study aims to determine an optimal proportion for partial replacement of PC with AAB and recommend a technique for it based on site conditions. Three modes of partial replacement are followed: combining all the dry ingredients for AAB and PC followed by the addition of the requisite liquids (PAM); combining the PC and the AAB concrete in two horizontal layers (PAH); and two vertical layers (PAV). 28-day old specimens are exposed to 10% v/v solutions of HCl, H₂SO₄, and HNO₃ to evaluate changes in mechanical, physical, and microstructural characteristics through compressive strength, corrosion depth, and microscopy. Based on deterioration in strength and integrity, PAH or PAV can be adopted in absence of acid attack, whereas PAM is recommended in presence of acid attack.

• Steel and Composite Structures
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• 제31권3호
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• pp.233-242
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• 2019

Early detection of damage bonding state such as insufficient bonding strength and interface partial contact defect for the explosive clad pipe is crucial in order to avoid sudden failure and even catastrophic accidents. A generalized and efficient model of the explosive clad pipe can reveal the relationship between bonding state and vibration characteristics, and provide foundations and priory knowledge for bonding state detection by signal processing technique. In this paper, the slender explosive clad pipe is regarded as two parallel elastic beams continuously joined by an elastic layer, and the elastic layer is capable to describe the non-uniform bonding state. By taking the characteristic beam modal functions as the admissible functions, the Rayleigh-Ritz method is employed to derive the dynamic model which enables one to consider inhomogeneous system and any boundary conditions. Then, the proposed model is validated by both numerical results and experiment. Parametric studies are carried out to investigate the effects of bonding strength and the length of partial contact defect on the natural frequency and forced response of the explosive clad pipe. A potential method for identifying the bonding quality of the explosive clad pipe is also discussed in this paper.

• Advances in concrete construction
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• 제13권 2호
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• pp.191-198
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• 2022

FIB is introduced as the sole guideline for the design purpose that results in a practical relationship for the torsional capacity of concrete beams strengthened with carbon fiber-reinforced polymer (CFRP). This study applies first-order reliability method to assess the reliability evaluation of the torsional capacity of CFRP-strengthened beams on the basis of FIB guidelines. In terms of steel reinforcement losses, this study applies a corrosion model to investigate the ceaseless deterioration of the existing structure. Hence, the average of reliability indices varies between 2.68 and 2.80, indicating the reliability viewpoint of the design methodologies. The average values are somehow low compared to the target values of reliability (3.0 or 3.5) applied in the calibration stage of the FIB guideline. In this way, the partial safety factors may change in the forthcoming guideline revisions. For this aim, the reliability of strengthening ratio was applied to assess the variation in the average value of the reliability index with different partial safety factors. The performance of parametric study for the factor proved that minimum values of 1.60 and 2.32 are required for target values of reliability (3.0 and 3.5), respectively.

• International Journal of Advanced Culture Technology
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• 제11권2호
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• pp.256-266
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• 2023

The purpose of this study is to investigate the relationship between stress and school life adaptation according to the degree of participation in physical education class and perception of middle school students. In order to achieve this research objective, the subjects of this study were sampled using cluster random sampling from male and female students attending middle schools in Gwangju Metropolitan City and Jeollanam-do in 2020. 150 males and 150 females, a total of 300 people were sampled. The statistical analysis used for data analysis was frequency analysis, exploratory factor analysis, reliability analysis, and multiple regression analysis using SPSS Windows 21.0 Version. The conclusions obtained in this study through data analysis by such methods and procedures are as follows. First, it was found that middle school students' participation in physical education classes and perceptions had a partial effect on stress. Second, it was found that the degree of participation and awareness of middle school students' physical education class had a partial effect on their adaptation to school life. Third, middle school students' stress was found to have a partial effect on school life adaptation.

• 대한통합의학회지
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• 제2권4호
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• pp.69-81
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• 2014

Purpose : The purpose of this study was to evaluate the effects of early muscle strengthening exercise on pain, shoulder function and sleep quality for rotator cuff tear patients. Method : The subjects of this study, partial tear of the rotator cuff diagnosed patients, four patients were picked up, who were agreed with this research. This experiment is comprised two experimental groups, with two control groups. The experimental groups recieved early muscle strengthening exercise for 6 weeks, which consisted of 4 times per week, 40 min of supervised exercise program. The control groups received a general movement treatment of 6 weeks which consisted of 4 times per week, 40 min, Pain, shoulder function and sleep quality measured by VAS, PPT and ROM, CMS, SST and PSQI. Result : In comparison of VAS, PPT and CMS, SST and PSQI was the experimental group showed a more improved. Conclusion : Therefore, early muscle strengthening exercise is useful to improve the pain, shoulder function and sleep quality for rotator cuff tear patients.

• Asian-Australasian Journal of Animal Sciences
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• 제19권5호
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• pp.690-694
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• 2006

There is limited information on the relationship between defoliation and root and rhizome development of kura clover (Trifolium ambiguum M. Bieb.). To determine the effects of defoliation severity on root and rhizome growth of young kura clover plant (seedling about 8 wk old), this research was conducted in 2002 (Experiment 1) and 2003 (Experiment 2) in a glasshouse at the University of Wisconsin-Madison. Four kura clover entries were used in this experiment: two were started from seed materials (ARS-2678 and 'Rhizo') and two were clones from mature, field-grown Rhizo kura clover plant. Three defoliation frequencies (2-, 4- and 6-wk intervals) and two defoliation intensities (complete and partial defoliation) were imposed on each of the four kura clover entries. Root, rhizome, and leaf dry matter (DM) generally increased with less frequent defoliation, however, the increase in rhizome DM was not significant between 4- or 6-wk defoliation periods. The root and leaf DM under complete defoliation (CD) were significantly lower than under partial defoliation (PD). In Exp. 1, rhizome DM was not significantly different between CD and PD; it was significantly lower under CD in Exp. 2. ARS-2678 showed excellent root development characteristics, however, its rhizome DM was significantly lower than Rhizo clones. The rhizome development from Rhizo clones was greater than that from seed materials. If maximum root and rhizome growth are expected from young kura clover plant, the intensity and frequency of defoliation should be minimized or defoliation should be avoided.

• Asian-Australasian Journal of Animal Sciences
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• 제6권4호
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• pp.597-600
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• 1993

An experiment was conducted using 160 Arbor Acres broiler strain of chickens to evaluate the effects of partial replacement of soyabean meal with feather meal on the diets of broiler chickens raised from day old to 8 weeks of age. Feathers, obtained from a local poultry processing plant, were boiled in water for 30 minutes, sun-dried and ground using a 2 mm sieve for inclusion into the experimental diets at 0, 1.5, 3.0 and 4.5% levels at the expense of soyabean meal. The feather meal was assayed and found to contain 86.5% crude protein and to be low in lysine, methionine and histidine amino acids. The inclusion of such processed feather meal up to 3% in the diet did not (p>0.05) affect growth or feed conversion ratio. However, the highest level of inclusion of feather meal in the diet, 4.5%, significantly reduced both growth rate and feed conversion ratio of the birds. The results of this experiment showed that up to 3% of water-boiled feather meal, which represents 12% of dietary protein, the equivalent of 6% level of use of soyabean meal in the diet, can be successfully included as a protein source in the diets of broiler chickens.

• 대한치과보철학회지
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• 제38권1호
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• pp.59-72
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• 2000

This study was performed to investigate the effects of tooth mobility and design of the direct retainer on the stress of supporting tissues in distal extension removable partial denture. Tooth mobility was simulated and four different types of direct retainer such as Alters clasp, I-bar clasp, wrought wire clasp, and Dalbo attachment were designed and stress on the support-ing tissues were measured and analyzed with straingauge method. The following conclusions were drawn from this study. 1. The stress revealed at the lingual side of alveolar bone of the abutment tooth in edentulous area was the largest. 2. The stress at the lingual side of alveolar bone of the abutment tooth in edentulous area was increased according to the increase of tooth mobility in I-bar clasp and Dalbo attachment. 3. The stress at the residual ridge crest was the great in Dalbo attachment on mobility 0, in I-bar clasp on mobility 1, and in wrought wire clasp on mobility 2. 4. There was little changes of stress according to the increase of tooth mobility at buccal and lingual side of the residual ridge crest and around the abutment teeth in dentulous area.

• 한국세라믹학회지
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• 제37권2호
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• pp.168-173
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• 2000

YMnO3 thin films were prepared on Pt/Ti/SiO2/Si substrate by chemical solution deposition method. The films were crystallized by heat-treatment at 85$0^{\circ}C$ for 1 hour. Effects of an annealing atmosphere(O2, Ar, vacuum) on the crystallization behavior and electridcal properties were investigated. YMnO3 thin films annealed under Ar atmosphere showed a superior crystallinity and a very strong c-aix preferred-orientation which was a polar axis. Leakage current density of the films decreased with lowering oxygen partial pressure of the annealing atmosphere. C-V and P-E ferroelectric hysteresis were observed only in the thin film heat-treated under Ar atmosphere.In order to prepare YMnO3 thin films having both low leakage current and ferroelectricity, the annealing atmsphere should be kept under a proper oxygen partial pressure which was about 1 Pa in this work. Leakage current density at 1 volt, dielectric constant($\varepsilon$r), remanent polarization(Pr), and coercive field(Ec) were 1.7$\times$10-8 A/$\textrm{cm}^2$, 25, 1.08$\mu$C/$\textrm{cm}^2$, and 100 kV/cm, respectively.

• Computers and Concrete
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• 제20권5호
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• pp.573-582
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• 2017

Chloride-induced cover cracking will aggravate the performance deterioration for RC structures under the chlorideladen environment, which may endanger the safety of structures and occupants. Traditional design method cannot ensure that a definite performance is satisfied. To overcome the defects, a study on the performance-based design method was carried out in this paper. Firstly, the limit state functions were established for the corrosion initiation and cover cracking. Thereafter, the uncertainty analysis was performed to study the effects of random factors on the time-dependent performances. Partial factor formulae were deduced through the first-order reliability method for performance verification. Finally, an illustrative example was presented and the sensitivity of cover depth to other parameters was carried out. It is found that the uncertainties of the random variables have great effects on the required cover depth. It is demonstrated that the performance-based design method can ensure that the target performance can be satisfied and support to formulate a rational maintenance and repair strategy for RC structures under the chloride environment.