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In recent times, the complexity of food styles and meal content has increased, leading to significant variations in macronutrient composition between meals. This phenomenon has coincided with a rise in obesity rates. We aimed to determine whether a large variation in macronutrient composition between meals results in reduced fat oxidation. A cross-over study was conducted with 13 healthy young men, using whole-body indirect calorimetry to test 24-h energy metabolic responses under three conditions: regular meals (R), high-carbohydrate breakfast (CB), or high-fat breakfast (FB), each with different macronutrient contents. The R condition included three meals daily with the same macronutrient composition. The CB condition included a high-carbohydrate meal at breakfast, high-fat meal at lunch, and high-carbohydrate meal at dinner. The FB condition included a high-fat meal at breakfast, high-carbohydrate meal at lunch, and high-carbohydrate meal at dinner. The daily macronutrient compositions were similar across the three conditions, except that CB and FB had larger variations in carbohydrate–fat balance between meals than R. The participants were tested in random order. During the dietary intervention, we compared 24-h whole-body metabolic parameters, including substrate oxidation (e.g., 24 h respiratory quotient [RQ]). No significant differences were observed in the measures of energy expenditure among the three conditions. However, after adjusting for the sleeping RQ on a preceding day, the estimated 24hRQ was lower under the FB condition (0.845) than under the R (0.854, P = 0.0077 vs. FB) and CB conditions (0.853, P = 0.016 vs. FB). No difference was observed in the magnitude of the 5-h RQ change from lunch to dinner under the CB condition and in the magnitude of change from breakfast to lunch under the FB condition. A large variation in the carbohydrate–fat balance between meals does not decrease daily fat oxidation. An FB may increase daily fat oxidation compared to a CB when the daily food quotient is constant, but this increase may not be owing to the upregulation of fat burning on a daily basis. [ABSTRACT FROM AUTHOR]

In this study, we design a differential power amplifier using a 110-nm RF CMOS process. To improve amplifier gain, we propose an active balun as a driver stage of the power amplifier. The passive input balun is removed to minimize the substrate loss. In the proposed power amplifier structure, the active balun converts a single-ended signal into a differential signal and at the same time provides sufficient gain as the driver stage of the power stage. To verify the feasibility of the proposed power amplifier structure, we designed a typical and the proposed power amplifier using identical processes and with the same design parameters, except for the driver stage and the input transformer of the typical power amplifier. The measured improvement of the gain of the proposed power amplifier is approximately 4.2 dB compared to that of the typical power amplifier. From the measured results, we successfully prove the feasibility of the proposed power amplifier. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the types and structures of small green spaces (SGs) that effectively reduce air temperature in urban blocks. Six highly developed blocks in Seoul, South Korea served as the research sites for this study. Air temperature was measured at the street level with mobile loggers on clear summer days from August to September in 2012. The measurements were repeated three times a day for three days. By analyzing the spatial characteristics, SGs within the six blocks were categorized into the four major types: polygonal, linear, single, and mixed. The result revealed that the polygonal and mixed types of SGs showed simple linear regression at a significant level ( p < 0.01 ). It indicated that the blocks’ urban heat island (UHI) mitigation ( ΔT Rmn ) increased in a linear fashion when the area and volume of these two types of green spaces increased. The area and volume of a polygonal SG with mixed vegetation, over 300 m 2 and 2300 m 3 , respectively, lowered the ΔT Rmn by 1 °C; SG with an area and volume of larger than 650 m 2 and 5000 m 3 , respectively, lowered the ΔT Rmn by 2 °C. The results of this study will be useful to urban planners and designers for determine the types and structures of urban green spaces to optimize the cooling effect, as well as how such green spaces should be designed and distributed. [ABSTRACT FROM AUTHOR]

In this study, we investigate the stability problems induced by undesired coupling between input feed lines and an output transformer for a linear CMOS power amplifier using a distributed active transformer (DAT) as an output balun. We extracted the losses of the input and output transformer, the undesired coupling, and the gains of the driver and the power stages to calculate the closed-loop gain. To determine the possibility of oscillation according to the location of the driver stage related to the undesired coupling and the closed-loop gain, we investigated the stability factor and stability circle. We show that the location of the driver stage of the power amplifier can be used to manage the value of the closed-loop gain. From the analyzed results, the driver stage of the linear power amplifier should be located outside the DAT to mitigate the stability issues. [ABSTRACT FROM AUTHOR]

Abstract: A wireless type of chip-to-chip communication (WCC) technology is proposed as the next generation of 3D semiconductor technology. To demonstrate the feasibility of this technology, we designed a coil, transmitter and receiver for wireless chip-to-chip communication using a 50-nm digital CMOS process. The coil is designed using inductive coupling with design parameters that include the number of turns, the metal width, and the space between adjacent metal lines. A differential transceiver structure is proposed for the WCC technology. The transmitter of the transceiver acts as a termination and bias circuit for the receiver while the transceiver is operating as a receiver. The receiver is designed with a typical differential amplifier and a latch to recover the transmitted original digital signal. The proposed transceiver and coil for the proposed WCC technology is implemented using commercial 50-nm digital CMOS technology. Experimental results successfully demonstrate the feasibility of the WCC technology. [Copyright &y& Elsevier]

Abstract: For autonomous manipulation in water, an underwater vehicle-manipulator system (UVMS) should be able to generate trajectori9es for the vehicle and manipulators and track the planned trajectories accurately. In this paper, for trajectory generation, we suggest a performance index for redundancy resolution. This index is designed to minimize the restoring moments of the UVMS during manipulation, and it is optimized without impeding the performance of a given task. As a result, the restoring moments of the UVMS are decreased, and control efforts are also reduced. For tracking control of the UVMS, a nonlinear optimal control with disturbance observer is proposed. This control is robust against parameter uncertainties, external disturbances, and actuator nonlinearities. Numerical simulations are presented to demonstrate the performance of the proposed coordinated motion control of the UVMS. The results show that control inputs for tracking are reduced, and the UVMS can successfully track generated trajectories. [Copyright &y& Elsevier]

The effects of urban heat islands (UHIs) comprise one of the most challenging issues in mitigating excessive heat. Existing studies have reported cooling effects from small greenspaces (SGs) and building-shaded spaces (BSs). However, more empirical studies are necessary to fully investigate the role of SGs in heat reduction as a cooling solution for urban microclimatic design and planning. In addition, only a few previous studies have used field studies to examine the cooling effects of SGs and compare them to those of BSs. The purpose of this study was to assess the cooling degrees of SGs and BSs and compare them at the urban block level. Six urban blocks located in Seoul, South Korea were selected as the study area. Based on block size, the selected urban blocks were divided into three pairs featuring different sizes of greenspace. Air temperature was measured via a transect survey on six clear, hot summer days. Datapoints were then classified into three landcover types: SGs, BSs, and paved spaces (PSs) exposed to solar radiation. To measure the cooling effects and compare the air temperatures of each cooling factor, a series of T-tests and ANOVA tests were conducted, after performing a spatial analysis of each block. The result show that the cooling effects of SGs surpassed those of BSs. The SGs' cooling effects on blocks with larger greenspace were greater than those with small greenspace. In blocks with larger greenspace, SG's cooling benefits outweighed those of BSs. It is also notable that block size was a decisive factor affecting the magnitude of cooling degrees; SG brought the greatest microclimatic benefits for the largest blocks. Our findings will contribute to optimal cooling designs using SGs and BSs by illustrating where SGs should be included to facilitate cost-effective cooling. [ABSTRACT FROM AUTHOR]

Groundwater is the sole water supply source on Jeju volcanic island in Korea and increasing levels of nitrate contamination have raised serious public concerns. This study was objected to understand the nitrate contamination mechanisms of the coastal groundwater overlain by a low-permeability layer in the western part of the island. The 2-yrs of quarterly groundwater monitoring from Sep. 2016 to Oct. 2018 revealed that NO 3 -N concentrations of 60.7% of sampled wells exceeded 10 mg/L, and those of 17.8% in the range of 3–10 mg/L, indicating those wells are already contaminated or under influence of potential sources. The spatio-temporal variation of groundwater chemistry and stable isotopic signatures suggested that nitrate originated mainly from chemical fertilizers due to agricultural activities and in part from liquefied manure affected by local livestock industries. Two transport processes appeared to be responsible for the nitrate in the confined coastal aquifer: 1) the direct penetration from the land surface through the wellbore leakage at incompletely grouted wells, and 2) the addition of nitrate-contaminated groundwater from upgradient areas where the confining layer is pinched out. Presently the potential nitrate sources are distributed up to 600 m above mean sea level(amsl), and the isotopic signatures implies that the provenance of coastal groundwater could be upland areas of up to 1280 m amsl. Subsequently, nitrate sources at upland areas could be picked up and carried down to the coastal groundwater under the confined condition of the basaltic aquifer that the regional groundwater recharge occurs. Consequently, groundwater contamination in the coastal aquifer should be considered in the big picture of groundwater system accommodating both regional and local flows. Nitrate transport along regional groundwater flows through a highly conductive basaltic aquifer in a volcanic island, South Korea. Unlabelled Image • About 60% of coastal groundwater is contaminated by nitrate in western Jeju Island. • Groundwater nitrate originates from chemical fertilizers and manure. • Confined aquifer is contaminated through borehole leakage and lateral transport. • Regional groundwater from mid-mountain areas transports nitrate to coastal aquifer. • Nitrate in coastal groundwater should be managed in a regional scale. [ABSTRACT FROM AUTHOR]

This study proposed an effective structure for the cathode of SOFC to reduce resistance, the honeycomb structure with dual porosity (micro and macro pores). A Sm 0.5 Sr 0.5 CoO 3−δ (SSC)–Sm 0.2 Ce 0.8 O 2−δ (SDC) composite cathode for solid oxide fuel cells, with a noble honeycomb structure comprising of nano and micro-sized pores, was fabricated by electrostatic slurry spray deposition (ESSD). The macro-pores distribute in the whole film with size range of 5–20 μm and micro-pores were formed throughout the skeleton with the size under 1 μm. This dual porosity composite cathode from interface to surface of the electrode was deposited by electrostatic slurry spray deposition (ESSD). Its electrochemical property was evaluated using electrochemical impedance spectroscopy and turned out to be enhanced compared to a conventional porous structure of cathode. The polarization resistances were significantly decreased with increasing measurement temperature. [ABSTRACT FROM AUTHOR]