Energy Efficiency Analysis of MISO-OFDM Communication Systems Considering Power and Capacity Constraints

In this paper, the energy efficiency of multi-input single-output and orthogonal frequency division multiplexing (MISO-OFDM) communication systems with power and capacity constraints is investigated. By formulating the power allocation problem of MISO-OFDM communication systems, the minimum subchannel transmission power is analyzed with power and capacity constraints. Simulation results indicate that there exists a specific minimum subchannel capacity threshold. Moreover, the energy efficiency of MISO-OFDM communication systems starts to increase only when the minimum subchannel capacity exceeds the specific threshold.     

A systematic approach for model refinement considering blind and recognized uncertainties in engineered product development

In recent years, virtual testing has played an increasingly important role in the design and evaluation of engineered products. However, it is challenging to build the highly accurate computational models for virtual testing. Blind and recognized uncertainties are often unintentionally incorporated. These uncertainties consequently decrease the predictive capability of the models. To this end, this paper proposes a systematic approach for model refinement that minimizes the impact of unrecognized blind and recognized epistemic uncertainties in computational modeling. The approach consists of three steps: model invalidity analysis (MIA), development of an invalidity reasoning tree (IRT), and invalidity sensitivity analysis (ISA). First, in the MIA, possible causes that lead to discrepancies between the experimental and simulation responses are identified through brainstorming. Next, the IRT is built using the affinity diagram. It sequentially lists and screens potential candidate issues for model refinement at the stages of conceptual, mathematical, and computational modeling. Finally, the ISA quantifies the effect of incorporating updates in the model to address potential candidate issues with the goal of reducing the impact of the blind and recognized uncertainties. The most critical candidates are determined by using a weighted decision matrix. To demonstrate the effectiveness of the proposed approach, a case study examining a smartphone liquid crystal display fracture is presented.     

Grafting maleic anhydride onto EVA and effect on the physical and rheological properties of PETG/EVA-g-MAH blends

Maleic anhydride (MAH) was grafted onto ethylene vinyl acetate copolymer (EVA) in the internal mixer in the presence of dicumyl peroxide (DCP), and a prepared reactive compatibilizer, MAH-g-EVA, was blended with Poly (ethylene glycol-co-cyclohexane-1,4-dimethanol terephthalate) (PETG). The gel content determination and element analysis (EA) was performed to confirm the grafting reaction. It was found that grafting reaction of MAH on to EVA could compete with crosslinking reaction of DCP during the modification process. In addition, the introduction of small amount of MAH showed a great effect on reducing gel content by decreasing crosslink reaction. As MAH content increased, grafted MAH concentration increased, whereas the grafting yield decreased. It was also confirmed that MAH-g-EVA acted as a reactive compatibilizer in the blend with PETG, and enhanced compatibility by reacting with the hydroxyl end groups, OH, of PETG. Addition of EVA in the blend leads a plastic deformation of PETG, and MAH had a great effect on enhancing interfacial adhesion resulting in significant increasing of % strain; however, improved compatibility could not be changed much in low strain tensile strength and Young's modulus. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Improved analysis of sinigrin in Ethiopian mustard

An ion‐pair reversed‐phase high‐performance liquid chromatography (HPLC) method was developed for the analysis of sinigrin in Ethiopian mustard (Brassica carinata A. Braun) seed and seed fractions. Separation was compared on several RP‐HPLC columns (Inertsil^® ODS‐4 C₁₈ and ZORBAX^® Eclipse XDB‐C₁₈) with an isocratic eluent containing 100% aqueous (aq.) tetramethylammonium bromide (10 mm , pH 5.0). Sinigrin retention was affected by HPLC variables including the type of ion‐pair reagent, buffer strength and pH, acetonitrile concentration, column temperature and eluent flow rate. Partial validation demonstrated this optimised chromatographic condition to be linear, accurate and precise. Multistage extraction using 70% (v/v) aq. methanol was more efficient than 50% (v/v) aq. acetonitrile. In addition, the matrix effect and recovery rate as well as processing efficiency of the analytical protocol were determined. This method is suitable for high throughput analysis of sinigrin in Ethiopian mustard seed and seed fractions.     

Biodegradable polycaprolactone/cuttlebone scaffold composite using salt leaching process

We prepared biodegradable polycaprolactone/cuttlebone scaffold composite by salt leaching process. In the first step, a co-continuous blend of biodegradable materials, polycaprolactone (PCL) and cuttlebone (CB), and an amount of sodium chloride salt particles were mixed using a stirrer. Next, the extraction of mineral salts using de-ionized distilled water was performed using a biodegradable PCL/CB scaffold with fully interconnected pores. Finally, the durable morphology of the scaffolds was fabricated by freeze-drying process at ?53 °C for 24 hrs in a vacuum. In addition, the quadrilateral pres ranged from about 250 to 300 ??m in diameter. Scanning electron microscopy (SEM) and mercury intrusion porosimeter techniques were carried out to characterize the pore morphology. By increasing the CB and sodium chloride salt particle content, the number of interconnected pores, material properties, and pore morphology were dramatically changed. The average compressive strengths (load at 50% strain) of the different porous PCL/CB scaffolds were found to decrease from 133 to about 79 (load at 50% strain, gf) with an increase in porosity. The values of the porosity increased as the sodium chloride salt volume fraction increased     

High-frequency dual mode pulsed wave Doppler imaging for monitoring the functional regeneration of adult zebrafish hearts

Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 MHz high-frequency array ultrasound imaging system. Phantom studies show that the Doppler flow mode of the dual mode is capable of measuring the flow velocity from 0.1 to 15 cm s⁻¹ with high accuracy (p-value = 0.974 > 0.05). In the in vivo study of zebrafish, both TD and Doppler flow signals were simultaneously obtained from the zebrafish heart for the first time, and the synchronized valve motions with the blood flow signals were identified. In the longitudinal study on the zebrafish heart regeneration, the parameters for diagnosing the diastolic dysfunction, for example, E/Em < 10, E/A < 0.14 for wild-type zebrafish, were measured, and the type of diastolic dysfunction caused by the amputation was found to be similar to the restrictive filling. The diastolic function was fully recovered within four weeks post-amputation.     

Integrated study of experiment and first‐principles computation for the characterization of a corium type ZrO8 complex in a Zr‐doped fluorite UO2

We, for the first time, observe ZrO₈ complex in Zr‐doped UO₂, which is a corium structure, using experimental characterization integrated with first‐principle computational validation. Atomic level structure of U_1?yZr_yO₂ pellets (y = 0.01, 0.03, 0.05, and 0.1) is identified using Raman spectroscopy measurement and X‐ray diffraction pattern analysis. The lattice constants shrink with increasing Zr doping levels, which consistently represents in the positive shift of T_2g Raman vibration peak around 445 cm^?1. More interestingly, conventionally unknown new Raman peak appears around 598 cm^?1, which has not been observed in neither a pure ZrO₂ nor UO₂ doped with tetravalent elements other than Zr. We unveil that the new peak originates from ZrO₈‐type complex formed on the fluorite UO₂. Our study provides precise understanding on the formation mechanisms and material properties of the corium in the hypervalent oxide.     

Android application that provides information on the foot and mouth disease in Korea

The foot and mouth disease is one of the most infectious diseases among artiodactyla. This occurred in and caused great damage to Korea in 2010. The effect was spread all over the country since it was not dealt with effectively at the early stages of the outbreak. Thus, this study aims to develop an application with the menu items such as the outbreak areas, and symptoms, and prompt reports of the foot and mouth disease so that stock farmers can download it through Smartphone and tablet PC web markets. The developed application enables stock farmers to get realtime information on the foot and mouth disease anywhere anytime, and to cope with this disease promptly when it occurs around their farming areas. It is expected that this application will be of help in preventing the foot and mouth disease from spreading further.