595 research outputs found

    A Study on the Flexural Behavior of Profiled Composite Beams

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    An analytical study on the behavior of composite beams, which are composed of cold-formed steel sheeting and normal strength concrete, is described. An analytical method to trace the nonlinear behavior of a composite beam is developed to include the nonlinear material properties of steel sheeting, reinforcing steel bar and concrete. However, since the method is complex and tedious to use, two simple formulas for the nonlinear moment-curvature relation of the composite beam have been proposed. A simple power model, which has been originally used to predict the flexural capacity of the beam to column connections, is proposed as the first formula. The second formula is composed of two experimental set of functions to express separately, the moment-curvature relation in the elastic and the plastic range. Both formulas have been proven to be accurate and useful for the design of profiled composite beams. The load-deflection behavior of the beams has been simulated by the step-by-step numerical integration method and is compared to available test results. The effects of the concrete cube strength and the thickness and strength of the cold-formed steel section on the flexural strength of the composite beam have also been studied

    Optimal Voltage Control Using an Equivalent Model of a Low-Voltage Network Accommodating Inverter-Interfaced Distributed Generators

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    The penetration of inverter-based distributed generators (DGs), which can control their reactive power outputs, has increased for low-voltage (LV) systems. The power outputs of DGs affect the voltage and power flow of both LV and medium-voltage (MV) systems that are connected to the LV system. Therefore, the effects of DGs should be considered in the volt/var optimization (VVO) problem of LV and MV systems. However, it is inefficient to utilize a detailed LV system model in the VVO problem because the size of the VVO problem is increased owing to the detailed LV system models. Therefore, in order to formulate and solve the VVO problem in an efficient way, in this paper, a new equivalent model for an LV system including inverter-based DGs is proposed. The proposed model is developed based on an analytical approach rather than a heuristic-fitting one, and it therefore enables the VVO problem to be solved using a deterministic algorithm (e.g., interior point method). In addition, a method to utilize the proposed model for the VVO problem is presented. In the case study, the results verify that the computational burden to solve the VVO problem is significantly reduced without loss of accuracy by the proposed model.11Ysciescopu

    A Study on Software-based Sensing Technology for Multiple Object Control in AR Video

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    Researches on Augmented Reality (AR) have recently received attention. With these, the Machine-to-Machine (M2M) market has started to be active and there are numerous efforts to apply this to real life in all sectors of society. To date, the M2M market has applied the existing marker-based AR technology in entertainment, business and other industries. With the existing marker-based AR technology, a designated object can only be loaded on the screen from one marker and a marker has to be added to load on the screen the same object again. This situation creates a problem where the relevant marker’should be extracted and printed in screen so that loading of the multiple objects is enabled. However, since the distance between markers will not be measured in the process of detecting and copying markers, the markers can be overlapped and thus the objects would not be augmented. To solve this problem, a circle having the longest radius needs to be created from a focal point of a marker to be copied, so that no object is copied within the confines of the circle. In this paper, software-based sensing technology for multiple object detection and loading using PPHT has been developed and overlapping marker control according to multiple object control has been studied using the Bresenham and Mean Shift algorithms

    The Properties of Type Ia Supernova Host Galaxies from the Sloan Digital Sky Survey

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    We investigate the properties and environments of Type Ia Supernova (SN Ia) host galaxies in the Stripe 82 of the Sloan Digital Sky Survey-II Supernova Survey centered on the celestial equator. Host galaxies are defined as the galaxy nearest to the supernova (SN) in terms of angular distance whose velocity difference from the SN is less than 1000 km s^{-1}. Eighty seven SN Ia host galaxies are selected from the SDSS Main galaxy sample with the apparent r-band magnitude m_r < 17.77, and compared with the SDSS Main galaxies. The SN Ia rates for early and late-type galaxies are 0.81 +- 0.19 SN (100yr)^{-1} and 0.99 +- 0.21 SN (100yr)^{-1}, respectively. We find that the host galaxies have a color distribution consistent with that of the Main galaxies, regardless of their morphology. However, host galaxies are on average brighter than the Main galaxies by ~ 0.3 mag over the range of -18.3 > M_r > -21.3. But the brighter ends of their luminosity distributions are similar. The distribution of the distance to the nearest neighbor galaxy shows that SNe Ia are more likely to occur in isolated galaxies without close neighbors. We also find that the SN Ia host galaxies are preferentially located in a region close to massive galaxy clusters compared to the Main galaxies.Comment: 10 pages, 8 figures, accepted for publication on Ap

    The burden and characteristics of tuberculosis/human immunodeficiency virus (TB/HIV) in South Korea: a study from a population database and a survey

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    <p>Abstract</p> <p>Background</p> <p>Although, in South Korea, human immunodeficiency virus/acquired immunodeficiency syndrome(HIV/AIDS) keeps increasing and tuberculosis(TB) burden is still significant, there have been few reports on TB/HIV cases. In this study, we investigated the burden and characteristics of TB/HIV patients in South Korea, an area with intermediate burden of TB and a low prevalent area with HIV/AIDS.</p> <p>Methods</p> <p>We identified patients with TB and cases with HIV between January 1 2001 and December 31 2005, from nationwide reporting system (TBnet and HIV/AIDS registry) through an electronic record linkage method. A questionnaire survey was also conducted and determined the rate of diagnosis of HIV among TB cases in public health units in 2005.</p> <p>Results</p> <p>The number of cases with both HIV and TB was 137 (0.07% among 197,562 TB cases) and the newly detected TB/HIV cases per 100,000 population was increasing annually: 2001, 0.025; 2002, 0.031; 2003, 0.025; 2004, 0.071; 2005, 0.095. Males between 20 and 59 years of age accounted for 87.6% of TB/HIV patients. Compared with patients with TB alone, those with TB/HIV had a higher percentage of extrapulmonary TB (8.0% vs 19.0%; p < 0.0001). The standardized prevalence ratio (SPR) of HIV among patients with TB was 18.46 (95% CI, 15.50-21.83). SPR of HIV among male TB patients aged 20-59 and extrapulmonary TB cases was 39.64 (95% CI, 32.87-47.40) and 43.21 (95% CI, 28.22-63.31) respectively. Through a questionnaire survey of public health units, six patients (0.08%) were confirmed as having HIV among 7,871 TB patients in public health centers in 2005, which is similar to the result from the study through nationwide reporting systems.</p> <p>Conclusions</p> <p>The prevalence rate of TB/HIV patients is still low but increasing in South Korea. Physicians should consider performing HIV tests among TB patients, especially in higher-risk groups, such as young males with extrapulmonary TB in South Korea.</p

    Zinc-chelated Vitamin C Stimulates Adipogenesis of 3T3-L1 Cells

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    Adipose tissue development and function play a critical role in the regulation of energy balance, lipid metabolism, and the pathophysiology of metabolic syndromes. Although the effect of zinc ascorbate supplementation in diabetes or glycemic control is known in humans, the underlying mechanism is not well described. Here, we investigated the effect of a zinc-chelated vitamin C (ZnC) compound on the adipogenic differentiation of 3T3-L1 preadipocytes. Treatment with ZnC for 8 d significantly promoted adipogenesis, which was characterized by increased glycerol-3-phosphate dehydrogenase activity and intracellular lipid accumulation in 3T3-L1 cells. Meanwhile, ZnC induced a pronounced up-regulation of the expression of glucose transporter type 4 (GLUT4) and the adipocyte-specific gene adipocyte protein 2 (aP2). Analysis of mRNA and protein levels further showed that ZnC increased the sequential expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα), the key transcription factors of adipogenesis. These results indicate that ZnC could promote adipogenesis through PPARγ and C/EBPα, which act synergistically for the expression of aP2 and GLUT4, leading to the generation of insulin-responsive adipocytes and can thereby be useful as a novel therapeutic agent for the management of diabetes and related metabolic disorders

    Effect of alcohol dehydrogenase 1C (ADH1C) genotype on vitamin A restriction and marbling in Korean native steers

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    Objective This work was to find the correlation of alcohol dehydrogenase 1C (ADH1C) genotype with vitamin A reduction and carcass traits during the vitamin A restriction period. Methods In study 1, 60 Korean native steers were fed a diet (890 IU/kg) with 8,000 IU and 0 IU of supplemental premix vitamin A/kg of dry matter (DM) for control and treatment group, respectively. The levels of serum vitamin A were analyzed through high preparative performance liquid chromatography, and the ADH1C genotype was analyzed based on polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP; 78.1% TT type, 21.9% TC type); however, CC type was not found. Then, the interaction between ADH1C and carcass traits on the vitamin A restriction was investigated in study 2. A total of 136 Korean native steers were fed a diet that included 930 IU/kg vitamin A of DM. Results Serum vitamin A in treatment was reduced to 112.4 IU/dL in steers with TT type of ADH1C, while for steers with TC type the concentration of serum vitamin A was dropped to 79.5 IU/dL (p<0.1) in study 1. This showed that TC type had the potential to lower serum vitamin A concentration during vitamin A restriction compared to TT type. In study 2 we found that eye muscle area, marbling and carcass weight in Korean native steers with TC type were higher than in steers with TT type (p<0.05). Conclusion The interaction between vitamin A restriction and TC type of ADH1C gene could have the potential of increasing the marbling in Korean native steers. These results indicated that steers with TC type of the ADH1C gene were more sensitive to the change of serum vitamin A than TT types. Furthermore, this finding has the potential to enable a higher marbling score under the condition of vitamin A restriction in Korean native steers
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