• Steel and Composite Structures
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• 제24권2호
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• pp.141-149
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• 2017

In this study, vibration analysis of fluid conveying microbeams under non-ideal boundary conditions (BCs) is performed. The objective of the present paper is to describe the effects of non-ideal BCs on linear vibrations of fluid conveying microbeams. Non-ideal BCs are modeled as a linear combination of ideal clamped and ideal simply supported boundary conditions by using the weighting factor (k). Non-ideal clamped and non-ideal simply supported beams are both considered to show the effects of BCs. Equations of motion of the beam under the effect of moving fluid are obtained by using Hamilton principle. Method of multiple scales which is one of the perturbation techniques is applied to the governing linear equation of motion. Approximate solutions of the linear equation are obtained and the effects of system parameters and non-ideal BCs on natural frequencies are presented. Results indicate that, natural frequencies of fluid conveying microbeam changed significantly by varying the weighting factor k. This change is more remarkable for clamped microbeams rather than simply supported ones.

• Journal of electromagnetic engineering and science
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• 제11권2호
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• pp.71-75
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• 2011

The sum-rate maximization rule can find an optimal user set that maximizes the sum capacity in multiple input multiple output (MIMO) broadcast channels (BCs), but the search space for finding the optimal user set becomes prohibitively large as the number of users increases. The proposed algorithm selects a user set of the largest effective channel norms based on statistical channel state information (CSI) for reducing the computational complexity, and uses Tomlinson-Harashima precoding (THP) for minimizing the interference between selected users in time-varying MIMO BCs.

• Asian-Australasian Journal of Animal Sciences
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• 제28권3호
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• pp.360-368
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• 2015

The present study evaluated the effect of controlled ryegrass-white clover herbage availability from day 128 until day 142 of pregnancy in comparison to unrestricted availability, on the performance of twin-bearing ewes of varying body condition score (BCS; 2.0, 2.5, or 3.0) and their lambs. It was hypothesised that under conditions of controlled herbage availability, the performance of lambs born to ewes with a greater BCS would be greater than those born to ewes with a lower BCS. During the period that the nutritional regimens were imposed, the pre- and post-grazing herbage masses of the Control regimen ($1,070{\pm}69$ and $801{\pm}30$ kg dry matter [DM]/ha) were lower than the ad libitum regimen ($1,784{\pm}69$ and $1,333{\pm}33kg\;DM/ha$; p<0.05). The average herbage masses during lactation were $1,410{\pm}31kg\;DM/ha$. Nutritional regimen had no effect on ewe live weight, BCS and back fat depth or on lamb live weight, indices of colostrum uptake, maximal heat production, total litter weight weaned or survival to weaning (p>0.05). The difference in ewe BCSs and back fats observed among body condition groups was maintained throughout pregnancy (p<0.05). At weaning, ewes from the BCS2.0 group had lower BCS and live weight ($2.4{\pm}0.2$, $74.3{\pm}2.6kg$) than both the BCS2.5 ($2.6{\pm}0.2$, $78.6{\pm}2.4kg$) and BCS3.0 ewes ($2.7{\pm}0.2$, $79.0{\pm}2.6kg$; p<0.05), which did not differ (p>0.05). Ewe BCS group had no effect on lamb live weight at birth or weaning or on maximal heat production (p>0.05). Serum gamma glutamyl transferase concentrations of lambs born to BCS3.0 ewes were higher within 36 hours of birth than lambs born to BCS2.0 ewes and BCS2.5 ewes ($51.8{\pm}1.9$ vs $46.5{\pm}1.9$ and $45.6{\pm}1.9IU/mL$, respectively [p<0.05]). There was, however, no effect of ewe body condition on lamb plasma glucose concentration (p>0.05). Lamb survival was the only lamb parameter that showed an interaction between ewe nutritional regimen and ewe BCS whereby survival of lambs born to BCS2.5 and BCS3.0 ewes differed but only within the Control nutritional regimen ewes (p<0.05). These results indicate farmers can provide twin-bearing ewes with pre- and post-grazing ryegrass-white clover herbage covers of approximately 1,100 and 800 kg DM/ha in late pregnancy, provided that herbage covers are 1400 in lactation, without affecting lamb performance to weaning. The present results also indicate that under these grazing conditions, there is little difference in ewe performance within the BCS range of 2.0 to 3.0 and therefore they do not need to be managed separately.

• 한국수정란이식학회지
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• 제20권3호
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• pp.279-287
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• 2005

본 연구는 젖소에 있어서 분만후 난소 활동의 재개 및 분만후 40일째 BCS가 $PGE_2a+PGE_2a+CIDR$ (PPC) program 적용에 미치는 영향을 구명하기 위하여 2002년부터 2003년까지 2년간에 걸쳐 축산연구소 및 천안 소재 전문 경영체 젖소농 장에서 사육중인 홀스타인 착유우를 대상으로 분만 후 난소 활동의 재개를 조사하기 위한 착유우21두 및 분만후 40일째 BCS가 PPC program 적용에 미치는 영향을 구명하기 위한 착유우 40두를 공시하여 수행한 결과 다음과 같은 성적을 얻었다. 1 분만후 처음으로 유즙중의 progesterone농도가 1.0ng/mL 이상을 나타내는 비율은 10${\~}$30일이 $42.9\%$, 31${\~}$50일이 $19.1\%$였고 분만 후 50일까지 1.0ng/mL 이상을 나타내지 않은 경우가 $38.1\%$였다. 2. 분만후 40일째부터 PPC program을 투입한 결과 1차 및 2차 $PGF_2a$ 처리에 대한 발정반응은 각각 $47.5\%$ 및 $52.4\%$였고, $PGF_2a+PGF_2a$ (PP) program투입에 의해 40두중 30두($75\%$)가 발정 반응을 나타내었다. PP program 투입에 의해 발정 반응을 나타내지 않은 10두에 대한 CIDR 처리의 발정 반응은 $50\%$를 나타내었다. 분만후 40일째에 PPC program 을 적용한 결과 40두중 35두가 발정 반응 ($87.5\%$)을 나타내었다. 3. 1차 및 2차 $PGF_2a$ 처리에 따른 발정 반응은 BCS 2.50 이하의 경우 13두중 8두($61.5\%$), BCS 2.75${\~}$3.50의 경우 27두중 22두($81.5\%$)로 2.75${\~}$3.50의 경우가 2.50 이하의 경우에 비하여 높은 발정반응을 나타내었다. 4. 2차 $PGF_2a$ 처리후 발정 반응을 나타내지 않은 개체에 대하여 CIDR을 처리한 결과, BCS 2.50이하의 경우 5두중 2두에서 발정 반응($40.0\%$)을 나타내었고 BCS 2.75${\~}$3.50의 경우 5 두중 4두에서 발정 반응($80\%$)을 나타내었다. 5. 분만후 40일째부터 PPC program을 적용하여 발정 반응을 검토한 결과 BCS 2.50 이하의 경우 13두중 10두가 발정 반응($76.9\%$)을 나타내었고 BCS 2.75${\~}$3.5의 경우 27두중 26두가 발정 반응($96.3\%$)을 나타내어 2.75${\~}$3.5의 경우가 2.50 이하의 경우에 비하여 높은 발정반응을 나타내었다.

• 대기
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• 제25권4호
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• pp.639-657
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• 2015

There is an increasing need to improve the air quality over South Korea to protect public health from local and remote anthropogenic pollutant emissions that are in an increasing trend. Here, we evaluate the performance of the WRF-Chem (Weather Research and Forecasting-Chemistry) model in simulating near-surface air quality of major Korean cities, and investigate the impacts of time-varying chemical initial and lateral boundary conditions (IC/BCs) on the air quality simulation using a chemical downscaling technique. The model domain was configured over the East Asian region and anthropogenic MICS-Asia 2010 emissions and biogenic MEGAN-2 emissions were applied with RACM gaseous chemistry and MADE/SORGAM aerosol mechanism. Two simulations were conducted for a 30-days period on April 2010 with chemical IC/BCs from the WRF-Chem default chemical species profiles ('WRF experiment') and the MOZART-4 (Model for OZone And Related chemical Tracers version 4) ('WRF_MOZART experiment'), respectively. The WRF_MOZART experiment has showed a better performance to predict near-surface CO, $NO_2$, $SO_2$, and $O_3$ mixing ratios at 7 major Korean cities than the WRF experiment, showing lower mean bias error (MBE) and higher index of agreement (IOA). The quantitative impacts of the chemical IC/BCs have depended on atmospheric residence time of the pollutants as well as the relative difference of chemical mixing ratios between the WRF and WRF_MOZART experiments at the lateral boundaries. Specifically, the WRF_MOZART experiment has reduced MBE in CO and O3 mixing ratios by 60~80 ppb and 5~10 ppb over South Korea than those in the WRF-Chem default simulation, while it has a marginal impact on $NO_2$ and $SO_2$ mixing ratios. Without using MOZART-4 chemical IC, the WRF simulation has required approximately 6-days chemical spin-up time for the East Asian model domain. Overall, the results indicate that realistic chemical IC/BCs are prerequisite in the WRF-Chem simulation to improve a forecast skill of local air quality over South Korea, even in case the model domain is sufficiently large to represent anthropogenic emissions from China, Japan, and South Korea.

• Parasites, Hosts and Diseases
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• 제49권4호
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• pp.437-440
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• 2011

Babesia spp. were detected from 4 asymptomatic pukus captured on a game ranch in central Zambia in October 2008. Blood smears were examined in 4 species of aymptomatic free-ranging antelopes, namely the puku (Kobus vordanii), reedbuck (Redunca arundinum), bushbuck (Tragelaphus sylvaticus), and kudu (Tragelaphus strepsiceros), and showed the presence of Babesia parasites only in the puku. In the puku, the prevalence of babesiosis was estimated at 33.3% (n=12), while the overall prevalence in all examined animals was 8.5% (n=47). The parasites showed morphological characteristics of paired ring-like stages with the length varying between $1.61{\mu}m$ and $3.02{\mu}m$ ($mean=2.12{\mu}m$, n=27; $SD=0.76{\mu}m$). Both the infected and non-infected pukus showed good body condition scores (BCS), while the dominant tick species detected from all animals were Rhipicephalus appendiculatus, Rhipicephalus spp., and Boophilus spp. To our knowledge this is the first report of Babesia spp. infection in pukus in Zambia. These findings suggest that wildlife could play an important role in the epidemiology of babesiosis in Zambia.

• Advances in nano research
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• 제7권6호
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• pp.431-442
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• 2019

Vibration analysis of carbon nanotubes (CNTs) is very essential field owing to their many promising applications in tiny instruments. In current study, the Eringen's nonlocal elasticity theory with clamped-clamped and clamped-free end conditions is utilized for the vibration analysis of armchair and zigzag SWCNTs. The Fourier method is utilized to solve the ordinary differential equation. The motion equation for this system is developed using a novel wave propagation method. Complex exponential functions have been used and the axial model depends on BCs that has been described at the edges of CNTs. The behavior of different nonlocal parameters is considered to find the vibrational frequency of SWCNTs. It is exhibited that the effect of frequencies against aspect ratio by varying the bending rigidity. It has been investigated that by increasing the nonlocal parameter decreases the frequencies and on increasing the aspect ratio increases the frequencies for both the tubes. To generate the fundamental natural frequencies of SWCNTs, computer software MATLAB engaged. The numerical results are validated with existing open text. Since the percentage of error is negligible, the model has been concluded as valid.