This article proposes a novel multiagent deep reinforcement learning method for the energy management of distributed electric vehicle charging stations with a solar photovoltaic system and energy ...storage system. In the literature, the conventional method is to calculate the optimal electric vehicle charging schedule in a centralized manner. However, in general, the centralized approach is not realistic under certain environments where the system operators for multiple electric vehicle charging stations handle dynamically varying data, such as the status of the energy storage system and electric vehicle-related information. Therefore, this article proposes a method that can compute the scheduling solutions of multiple electric vehicle charging stations in a distributed manner while handling run-time time-varying dynamic data. As shown in the data-intensive performance evaluation, it can be observed that the proposed method achieves a desirable performance in terms of reducing the operation costs of electric vehicle charging stations.
•We fabricated a sensor with high sensitivity toward H2.•It was prepared by drop-casting MoS2 solution and functionalization with Pd nanodots.•Upon H2 exposure, Pd was converted to Pd-hydride with ...lower work function than MoS2.•Pristine MoS2 showed no change when exposed to a 1% hydrogen-containing gas.•However, functionalized MoS2 showed a 35.3% resistance change.
A facile, scalable and low-cost strategy for fabricating hydrogen sensors with few-layered Pd-functionalized MoS2 according to a simple solution process is reported. The sensors were prepared by drop-casting a MoS2-containing solution onto a SiO2 substrate and functionalizing the surface of the MoS2 with Pd using evaporation. Patterned deposition of Cr/Au on top of the MoS2-coated SiO2 substrate was then performed using evaporation through a shadow mask to place the micro electrodes on the substrate. The fabricated Pd-MoS2 sensors successfully detected hydrogen gas diluted by air at room temperature. With exposure to hydrogen gas, the Pd was converted to palladium hydride, which has a lower work function than MoS2, resulting in the transfer of electrons from palladium hydride to MoS2, thereby decreasing the resistance of the sensor. The functionalized MoS2 showed a 35.3% resistance change when exposed to a 1% hydrogen-containing gas, while the pristine MoS2 showed no reaction. The lower limit of detection of the resulting functionalized MoS2 sensor was 50ppm.
Abstract
For steady electroconversion to value-added chemical products with high efficiency, electrocatalyst reconstruction during electrochemical reactions is a critical issue in catalyst design ...strategies. Here, we report a reconstruction-immunized catalyst system in which Cu nanoparticles are protected by a quasi-graphitic C shell. This C shell epitaxially grew on Cu with quasi-graphitic bonding via a gas–solid reaction governed by the CO (g) - CO
2
(g) - C (s) equilibrium. The quasi-graphitic C shell-coated Cu was stable during the CO
2
reduction reaction and provided a platform for rational material design. C
2+
product selectivity could be additionally improved by doping
p
-block elements. These elements modulated the electronic structure of the Cu surface and its binding properties, which can affect the intermediate binding and CO dimerization barrier. B-modified Cu attained a 68.1% Faradaic efficiency for C
2
H
4
at −0.55 V (vs RHE) and a C
2
H
4
cathodic power conversion efficiency of 44.0%. In the case of N-modified Cu, an improved C
2+
selectivity of 82.3% at a partial current density of 329.2 mA/cm
2
was acquired. Quasi-graphitic C shells, which enable surface stabilization and inner element doping, can realize stable CO
2
-to-C
2
H
4
conversion over 180 h and allow practical application of electrocatalysts for renewable energy conversion.
Algae and bacteria have coexisted ever since the early stages of evolution. This coevolution has revolutionized life on earth in many aspects. Algae and bacteria together influence ecosystems as ...varied as deep seas to lichens and represent all conceivable modes of interactions — from mutualism to parasitism. Several studies have shown that algae and bacteria synergistically affect each other's physiology and metabolism, a classic case being algae–roseobacter interaction. These interactions are ubiquitous and define the primary productivity in most ecosystems. In recent years, algae have received much attention for industrial exploitation but their interaction with bacteria is often considered a contamination during commercialization. A few recent studies have shown that bacteria not only enhance algal growth but also help in flocculation, both essential processes in algal biotechnology. Hence, there is a need to understand these interactions from an evolutionary and ecological standpoint, and integrate this understanding for industrial use. Here we reflect on the diversity of such relationships and their associated mechanisms, as well as the habitats that they mutually influence. This review also outlines the role of these interactions in key evolutionary events such as endosymbiosis, besides their ecological role in biogeochemical cycles. Finally, we focus on extending such studies on algal–bacterial interactions to various environmental and bio-technological applications.
Summary Background Compared with open resection, laparoscopic resection of rectal cancers is associated with improved short-term outcomes, but high-level evidence showing similar long-term outcomes ...is scarce. We aimed to compare survival outcomes of laparoscopic surgery with open surgery for patients with mid-rectal or low-rectal cancer. Methods The Comparison of Open versus laparoscopic surgery for mid or low REctal cancer After Neoadjuvant chemoradiotherapy (COREAN) trial was an open-label, non-inferiority, randomised controlled trial done between April 4, 2006, and Aug 26, 2009, at three centres in Korea. Patients (aged 18–80 years) with cT3N0–2M0 mid-rectal or low-rectal cancer who had received preoperative chemoradiotherapy were randomly assigned (1:1) to receive either open or laparoscopic surgery. Randomisation was stratified by sex and preoperative chemotherapy regimen. Investigators were masked to the randomisation sequence; patients and clinicians were not masked to the treatment assignments. The primary endpoint was 3 year disease-free survival, with a non-inferiority margin of 15%. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov , number NCT00470951. Findings We randomly assigned 340 patients to receive either open surgery (n=170) or laparoscopic surgery (n=170). 3 year disease-free survival was 72·5% (95% CI 65·0–78·6) for the open surgery group and 79·2% (72·3–84·6) for the laparoscopic surgery group, with a difference that was lower than the prespecified non-inferiority margin (–6·7%, 95% CI −15·8 to 2·4; p<0·0001). 25 (15%) patients died in the open group and 20 (12%) died in the laparoscopic group. No deaths were treatment related. Interpretation Our results show that laparoscopic resection for locally advanced rectal cancer after preoperative chemoradiotherapy provides similar outcomes for disease-free survival as open resection, thus justifying its use. Funding National Cancer Center, South Korea.
Disposal of saline effluent from desalination plants, agricultural drainage water, and other industries is an increasing problem worldwide. Saline effluent has long been considered waste brine and ...traditional approaches to its disposal have included evaporation ponds, deep wells, and coastal discharge. However, such effluent is now being considered as a saline resource; therefore, alternative approaches have been developed to extract available salts and to recover purified water. In this study, techniques to dispose of rejected brine were investigated and alternative salt recovery methods that have been developed and widely employed were reviewed. Evaporation and cooling to extract salts from retentate has been widely used worldwide, but use of the membrane separation technique has been increasing rapidly owing to the development of cheaper and higher performance membranes. Electrodialysis, ion-exchange, eutectic freezing, and chemical processing can also be used to recover salts from retentate. Currently, hybrid systems that combine two or more techniques, such as the nanofiltration (pretreatment)–reverse osmosis (concentration)–thermal processes (crystallization), are being developed and used actively to increase the amount of extracted salt and reduce the final volume of rejected brine. Economic analysis of concentrate utilization in comparison with disposal was performed in this study. Based on the cost of producing salts, the multi-stage flash (MSF) distillation and electrodialysis and Dow chemical process were relatively expensive when compared to nanofiltration and membrane crystallization, evaporation, and ion-exchange techniques. However, technical developments for increasing the performance efficiency must be further investigated to reduce the cost of desalting processes.
► Desalting process techniques and economic analysis of salt recovery were reviewed. ► Economic analysis of disposal cost of saline feed to processes was performed. ► Disposal costs of the suggested techniques are relatively high. ► The alternative saline effluent treatments are viable by commercializing salts.
An advanced driver-assistance system (ADAS), based on lane detection technology, detects dangerous situations through various sensors and either warns the driver or takes over direct control of the ...vehicle. At present, cameras are commonly used for lane detection; however, their performance varies widely depending on the lighting conditions. Consequently, many studies have focused on using radar for lane detection. However, when using radar, it is difficult to distinguish between the plain road surface and painted lane markers, necessitating the use of radar reflectors for guidance. Previous studies have used long-range radars which may receive interference signals from various objects, including other vehicles, pedestrians, and buildings, thereby hampering lane detection. Therefore, we propose a lane detection method that uses an impulse radio ultra-wideband radar with high-range resolution and metal lane markers installed at regular intervals on the road. Lane detection and departure is realized upon using the periodically reflected signals as well as vehicle speed data as inputs. For verification, a field test was conducted by attaching radar to a vehicle and installing metal lane markers on the road. Experimental scenarios were established by varying the position and movement of the vehicle, and it was demonstrated that the proposed method enables lane detection based on the data measured.
Abstract
Electrocatalysis, whose reaction venue locates at the catalyst–electrolyte interface, is controlled by the electron transfer across the electric double layer, envisaging a mechanistic link ...between the electron transfer rate and the electric double layer structure. A fine example is in the CO
2
reduction reaction, of which rate shows a strong dependence on the alkali metal cation (M
+
) identity, but there is yet to be a unified molecular picture for that. Using quantum-mechanics-based atom-scale simulation, we herein scrutinize the M
+
-coupling capability to possible intermediates, and establish H
+
- and M
+
-associated ET mechanisms for CH
4
and CO/C
2
H
4
formations, respectively. These theoretical scenarios are successfully underpinned by Nernstian shifts of polarization curves with the H
+
or M
+
concentrations and the first-order kinetics of CO/C
2
H
4
formation on the electrode surface charge density. Our finding further rationalizes the merit of using Nafion-coated electrode for enhanced C2 production in terms of enhanced surface charge density.
Angiogenesis induction into damaged sites has long been an unresolved issue. Local treatment with pro-angiogenic molecules has been the most common approach. However, this approach has critical side ...effects including inflammatory coupling, tumorous vascular activation, and off-target circulation. Here, the concept that a structure can guide desirable biological function is applied to physically engineer three-dimensional channel networks in implant sites, without any therapeutic treatment. Microchannel networks are generated in a gelatin hydrogel to overcome the diffusion limit of nutrients and oxygen three-dimensionally. Hydrogel implantation in mouse and porcine models of hindlimb ischemia rescues severely damaged tissues by the ingrowth of neighboring host vessels with microchannel perfusion. This effect is guided by microchannel size-specific regenerative macrophage polarization with the consequent functional recovery of endothelial cells. Multiple-site implantation reveals hypoxia and neighboring vessels as major causative factors of the beneficial function. This technique may contribute to the development of therapeutics for hypoxia/inflammatory-related diseases.
Tracheal resection has limited applicability. Although various tracheal replacement strategies were performed using artificial prosthesis, synthetic stents and tissue transplantation, the best method ...in tracheal reconstruction remains to be identified. Recent advances in tissue engineering enabled 3D bioprinting using various biocompatible materials including living cells, thereby making the product clinically applicable. Moreover, clinical interest in mesenchymal stem cell has dramatically increased. Here, rabbit bone marrow-derived mesenchymal stem cells (bMSC) and rabbit respiratory epithelial cells were cultured. The chondrogenic differentiation level of bMSC cultured in regular media (MSC) and that in chondrogenic media (d-MSC) were compared. Dual cell-containing artificial trachea were manufactured using a 3D bioprinting method with epithelial cells and undifferentiated bMSC (MSC group,
= 6) or with epithelial cells and chondrogenic-differentiated bMSC (d-MSC group,
= 6). d-MSC showed a relatively higher level of glycosaminoglycan (GAG) accumulation and chondrogenic marker gene expression than MSC in vitro. Neo-epithelialization and neo-vascularization were observed in all groups in vivo but neo-cartilage formation was only noted in d-MSC. The epithelial cells in the 3D bioprinted artificial trachea were effective in respiratory epithelium regeneration. Chondrogenic-differentiated bMSC had more neo-cartilage formation potential in a short period. Nevertheless, the cartilage formation was observed only in a localized area.
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