Search

Hydrogen production, which is in the spotlight as a promising eco-friendly fuel, and the need for inexpensive and accurate electronic devices in the biochemistry field are important emerging technologies. However, the use of electrocatalytic devices based on expensive noble metal catalysts limits commercial applications. In recent years, to improve performance and reduce cost, electrocatalysts based on cheaper copper or nickel materials have been investigated for the non-enzymatic glucose oxidation reaction (GOR) and hydrogen evolution reaction (HER). In this study, we demonstrate a facile and easy electrochemical method of forming a cheap nickel copper double hydroxide (NiCu-DH) electrocatalyst deposited onto a three-dimensional (3D) CuNi current collector, which can effectively handle two different reactions due to its high activity for both the GOR and the HER. The as-prepared electrode has a structure comprising abundant 3D-interconnected porous dendritic walls for easy access of the electrolyte ions and highly conductive networks for fast electron transfer; additionally, it provides numerous electroactive sites. The synergistic combination of the dendritic 3D-CuNi with its abundant active sites and the self-made NiCu-DH with its excellent electrocatalytic activity toward the oxidation of glucose and HER enables use of the catalyst for both reactions. The as-prepared electrode as a glucose sensor exhibits an outstanding glucose detection limit value (0.4 μM) and a wide detection range (from 0.4 μM to 1.4 mM) with an excellent sensitivity of 1452.5 μA/cm

Rapid economic growth and industrialization have brought material abundance and convenience, but also social and environmental problems such as global warming, climate change, and ozone depletion. For this reason, the public and governments have continued to make efforts to reduce carbon oxide emissions worldwide over the past few decades. To achieve this mission, cap-and-trade regulations have been introduced as one of the most effective market-based mechanisms to control carbon emissions. Accordingly, sustainability efforts, including the development of green products and innovating manufacturing technologies, are being made by companies in supply chains to reduce their carbon emissions. In the context of sustainability innovations and carbon emission constraints, this article investigates pricing decisions, the degree of sustainability efforts, and carbon caps under two different supply chain contracts—in this case, wholesale price contract and cost-sharing contract. This article establishes a Stackelberg game model under each of the supply chain contract types and presents the equilibrium decisions made by players of the game. Major findings of this article reveal that (i) the performance of the supply chain is considerably affected by the presence of a carbon cap; (ii) the higher the carbon cap set by a government is, the more sustainability innovation efforts the supply chain makes; and (iii) the supply chain can improve its profitability and its sustainability under a cost-sharing contract.

Rapid economic growth and industrialization have brought us material abundance and greater convenience, while also causing socio-environmental problems such as the rapid depletion of resources, unexpected natural disasters, and environmental destruction. For these reasons, environmental issues have attracted public and governmental attention around the world over the past few decades. As a result, environmental sustainability has become a critical indicator for evaluating the success and efficiency of supply chain management schemes. For a sustainable supply chain, many governments are employing subsidy policies to encourage consumers to purchase environment-friendly (green) products. This article considers a supply chain composed of two competing manufacturers and two retailers. The first manufacturer produces a green product, while the second manufacturer produces a nongreen product. Each of the two retailers can sell only a green product, only a nongreen product, or both green and nongreen products. In the market, consumers purchasing the first manufacturer’s green products can receive certain subsidies from the government. The amounts of the government subsidies that a consumer receives depend on the greenness degree of the product. Using a three-stage Stackelberg game framework, this article discusses equilibrium decisions on pricing and greenness for four different distribution channel structures. Major findings of this study reveal that (i) the government subsidy has a positive impact on the greenness degree and the demand for green products; (ii) the government subsidy level depends on the manufacturers’ distribution channel strategy types; and (iii) the greater the environmentally negative impact of a green product, the lower the level of the government subsidy paid for purchasing green products. Based on these findings, this article suggests that policymakers focus on establishing the policies that encourage the purchase of green products for the sustainability of a society and a supply chain.

An efficient reduction method to obtain high-quality graphene sheets from mass-producible graphene oxide is highly desirable for practical applications. Here, we report an in situ deoxidation and graphitization mechanism for graphene oxide that allows for high-quality reduced graphene oxide sheets under the low temperature condition (

This study was designed to identify the suppression characteristics and mechanisms of flow-induced vibration occurring in a test cylinder installed on an elastic support by placing a control cylinder with a smaller diameter behind the test cylinder. To identify the effects of this installation, the diameter and location of the control cylinder were varied systematically to examine the characteristics of flowinduced vibration occurring in the test cylinder. Furthermore, the fluctuating streamwise velocity of the wake flow of the test cylinder was examined as it varied with the installation of the control cylinder. Subsequently, the peripheral flow of the test cylinder installed in front of the control cylinder was examined via a flow visualization test that used a water channel. Results obtained from the experiments are summarized as follows. i) Flow-induced vibrations in the test cylinder, which occur and are varied by the installation of the control cylinder behind the test cylinder, have four types that change according to the different diameters and locations of the control cylinder. ii) The domain of the positions of the control cylinder, which can suppress flow-induced vibration in the test cylinder, increases in proportion with the diameter of the control cylinder. iii) Flow-induced vibration that will be generated in the test cylinder is predicted by examining the distribution of the flow velocity of the wake flow and the intensity of the fluctuating streamwise velocity at the lower flow velocity level before it reaches a flow velocity that can create flow-induced vibration in the test cylinder.

Yoon, J.C. and Song, D.S., 2018. Preliminary Study for Detecting of Ocean Wave Parameters using CCD Images. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1371–1375. Coconut Creek (Florida), ISSN 0749-0208. Recently, researchers have been developed the technology for monitoring in the coastal zone using a remote sensing to manage and analyze the beach processes. Many of these approaches translate the data model of beach process as a queue of avoidance of emergency situation in a beach, such as coastal erosion risk management. However, sensor-based approaches have a crucial limitation, which needs a high cost and has a worry about malfunction. To overcome these problems, a video-based beach monitoring system, which can analyze the wave periods and height, was introduced in this study. A CCD camera is one of best choice to monitor a movement of arbitra...

Utilizing the broad-band solar spectrum for sea water desalination is a promising method that can provide fresh water without sophisticated infrastructures. However, the solar-to-vapour efficiency has been limited due to the lack of a proper design for the evaporator to deal with either a large amount of heat loss or salt accumulation. Here, these issues are addressed via two cost-effective approaches: I) a rational design of a concave shaped supporter by 3D-printing that can promote the light harvesting capacity via multiple reflections on the surface; II) the use of a double layered photoabsorber composed of a hydrophilic bottom layer of a polydopamine (PDA) coated glass fiber (GF/C) and a hydrophobic upper layer of a carbonized poly(vinyl alcohol)/polyvinylpyrrolidone (PVA/PVP) hydrogel on the supporter, which provides competitive benefit for preventing deposition of salt while quickly pumping the water. The 3D-printed solar evaporator can efficiently utilize solar energy (99%) with an evaporation rate of 1.60 kg m-2 h-1 and efficiency of 89% under 1 sun irradiation. The underlying reason for the high efficiency obtained is supported by the heat transfer mechanism. The 3D-printed solar evaporator could provide cheap drinking water in remote areas, while maintaining stable performance for a long term.

In this paper, we propose a method for extracting humans in the foreground of video frames using color and depth information. To ensure real-time performance and to increase accuracy, we classify a video frame into two parts by degree of noise: head region with high noise level, and non-head region with low noise level. Then, we apply a high-computational geodesic matting algorithm to the noisy head region that includes hair, and a low-computational hole filling with smoothing method to other regions. Additionally, we modify the traditional color-based geodesic segmentation algorithm to consider additional depth information. Then, we apply temporal/spatial smoothing to the blended foreground mask in order to enhance the coherence between video frames. Experimental results show that the proposed method outperforms a previous approach by accuracy and performance.

We report a three-dimensional graphene network decorated with nickel nanoparticles as a current collector to achieve outstanding performance in Ni(OH)2-based supercapacitors with excellent energy density. A cost-efficient and single-step fabrication method creates nickel-particle decorated three-dimensional graphene networks (Ni–GNs) with an excellent electrical conductivity of 107 S m−1 and a surface area of 16.4 m2 g−1 that are superior to those of carbon alternatives and commercial 3D-Ni foam, respectively. The supercapacitor in which Ni(OH)2 active materials are deposited on Ni–GNs exhibited an outstanding capacitance value of 3179 F g−1 at 10 A g−1 in a three-electrode system and 90% of capacitance retention after 10 000 cycles. Furthermore, it showed an outstanding energy density of 197.5 W h kg−1 at a power density of 815.5 W kg−1 when tested in a two-electrode system. To the best of our knowledge, our device realized the world record value of energy density with a high rate capability and good cycle stability among Ni(OH)2-based supercapacitors. The excellent electrical properties of easily synthesized Ni–GNs as the ideal current collector clearly suggest a straightforward way to achieve great performance supercapacitors with both high energy density and power density.

Highlights The flexible 3D porous structure with a large surface area provides pathways for rapid ion/electron transport and ion diffusion as well as numerous electroactive sites.The wire-shaped supercapacitor exhibits a high energy density of 153.3 Wh kg−1 and a power density of 8810 W kg−1.The hybrid device demonstrates excellent durability under various mechanical deformations. Electronic supplementary material The online version of this article (10.1007/s40820-019-0356-z) contains supplementary material, which is available to authorized users., We report a wire-shaped three-dimensional (3D)-hybrid supercapacitor with high volumetric capacitance and high energy density due to an interconnected 3D-configuration of the electrode allowing for large number of electrochemical active sites, easy access of electrolyte ions, and facile charge transport for flexible wearable applications. The interconnected and compact electrode delivers a high volumetric capacitance (gravimetric capacitance) of 73 F cm−3 (2446 F g−1), excellent rate capability, and cycle stability. The 3D-nickel cobalt-layered double hydroxide onto 3D-nickel wire (NiCo LDH/3D-Ni)//the 3D-manganese oxide onto 3D-nickel wire (Mn3O4/3D-Ni) hybrid supercapacitor exhibits energy density of 153.3 Wh kg−1 and power density of 8810 W kg−1. The red light-emitting diode powered by the as-prepared hybrid supercapacitor can operate for 80 min after being charged for tens of seconds and exhibit excellent electrochemical stability under various deformation conditions. The results verify that such wire-shaped 3D-hybrid supercapacitors are promising alternatives for batteries with long charge–discharge times, for smart wearable and implantable devices. Electronic supplementary material The online version of this article (10.1007/s40820-019-0356-z) contains supplementary material, which is available to authorized users.

In this paper, we propose a three-dimensional (3D) convolutional neural network (CNN)-based method for predicting the degree of motion sickness induced by a 360° stereoscopic video. We consider the user's eye movement as a new feature, in addition to the motion velocity and depth features of a video used in previous work. For this purpose, we use saliency, optical flow, and disparity maps of an input video, which represent eye movement, velocity, and depth, respectively, as the input of the 3D CNN. To train our machine-learning model, we extend the dataset established in the previous work using two data augmentation techniques: frame shifting and pixel shifting. Consequently, our model can predict the degree of motion sickness more precisely than the previous method, and the results have a more similar correlation to the distribution of ground-truth sickness.