Abstract

This paper reports a synthesis strategy to develop Ni@yolk-meso-SiO2 by adopting the leaching and re-deposition of silica in mild alkaline solution with CTAB as stabilizer. It was compared to Ni@SiO2 core-shell catalyst and point out their difference in catalytic performance. The catalyst shows stable and near equilibrium conversion of methane and carbon dioxide for 50 hours. The increased in surface area and total pore volume contributed its high activity and stability.

Abstract

This article has presented the inlet port diameter-bore ratios (IPD/B) on engine performance and emission characteristics. For the first time, the effect of inlet port diameter-bore ratio on the residual gas, peak firing pressure rise and effective release energy were discussed. Through combined experimental and simulative methods the drawbacks of hardware optimization method were eliminated. The results of the research show that the IPD/B ratio has a significant effect on the residual gas, peak firing pressure rise and effective release energy. Following increased IPD/B ratio from 0.3 – 0.5. The residual gas ratio shows an uptrend from 0.11% to 0.14%. The effective release energy increases from 0.33 KJ to maximum value of 0.45 KJ after that decrease. At IPD/B ratio is 0.4 effective release energy achieved the maximum values. The HC and CO emission was decreased, but the NOx was increased until a maximum value was achieved after that, a subsequent decrease. At IPD/B ratio is 0.4 the NOx was maximum value of 0.66 g/kWh, the BSFC was minimum value of 849.5 g/kWh.

Abstract

High temperature heat transfer, mass transfer, and thermochemical storage performances of the solar driven CO2 reforming of methane are numerically investigated along reactor length. A pseudo-homogeneous mathematical model is developed to simulate the heat and mass transfer processes coupled with thermochemical reaction kinetics in photo-thermochemical reactor with radiative heat loss. Thus, the temperature profile at the surface of the solid phase and the temperature profile in the gas phase are obtained. In addition, the conversions of reactants of CH4 and CO2 are studied under different operating temperatures. On the other hand, the DFR of H2 and QChem are also evaluated at the operating temperature.

Abstract

Power-to-Fuel technologies are important for reducing fossil fuel consumption in the transport sector. Carbon dioxide (CO2) from biogas and hydrogen (H2) production from wind electrolysis provide convenient components for the synthesis of methanol. This study evaluates the environmental performance of a novel Power-to-Fuel (PTF) system, in which methanol is produced at a biogas production plant. A Life Cycle Assessment is carried out considering five feasible process routes in order to identify the one that delivers greater environmental benefits. The proposed system is also compared to a system of conventional methanol production. Results show improvements in most impact categories, which make it interesting from the environmental point of view.

Abstract

The exploration of efficient utilization of lignin is very important and necessary for the applied biomass energy and sustainable development. In this work, hydrolyzed lignin residue, contenting more than 70% lignin, obtained from acid hydrolysis of sorghum straw was reused to synthesized ultrahigh surface area and hierarchical porous activated carbon for the first time. As-prepared nanomaterial (HLAC-1) presented unusual features such as unique interconnected porous structure, ultrahigh surface area (ca.2927 m2 /g), large total volume (ca.1.65 cm3 /g) and a high graphitization degree. Furthermore, as the electrode material for supercapacitor, HLAC-1 also exhibited remarkably high capacitance (400 F/g at 0.5 A/g) and superior cycling stability (99.1％ capacity retention after 20,000 cycles at 5 A/g) in 6M KOH aqueous electrolyte. A high energy density of 9.53 Wh/kg at a powder density of 53.22 W/kg (6.96 Wh/kg at a powder density of 2532.39 Wh/kg) have been achieved in KOH aqueous supercapacitors, indicating that the conversion of hydrolyzed lignin residue from activated carbon is very attractive and promising for the application in supercapacitor.

Abstract

Aiming at the demand of comprehensive vulnerability assessment in shipboard power system security defense, the paper proposed a vulnerability status description model of shipboard power system. The structure and physical properties of shipboard power network were fully analyzed. The product space which was called shipboard power network comprehensive vulnerability index set was established by degrees, betweenness, maximum connection sub-diagram scale, reliability indexes. Secondly, the normalized index sets were compactness and thepnormon the compactness sets were continuous were proved in this paper. The norm of vulnerability index was vulnerability output equation of shipboard power system. Using the norm on the product space, multi-scale integrated shipboard power network vulnerability norm was proposed, and the comprehensive structure performance evaluation of the shipboard power system network was formed. The index describes the change tendency of the shipboard power network comprehensive vulnerability. Finally, the test on a certain type of shipboard power network demonstrates the validity of the model.

Abstract

The long‐term production of U.S. tight oil is forecast by using a composite model combining the Generalized Weng and Gompertz models. We show that U.S. tight oil production is likely to reach a peak within ten years, between 2019 and 2028, at a production rate between 7 and 13 million barrels per day (Mb/d), depending on the size of the ultimately recoverable resource (URR) estimate. Our most‐likely ‘medium‐case’ URR scenario suggests the peak year is probably around 2025, at a production rate of about 10 Mb/d. Comparing our results with those of the U.S. Energy Information Administration (EIA) suggests that the EIA is over‐optimistic in its long‐term production forecast of U.S. tight oil.

Abstract

Technologies are changing in both the mobility sector, with electric, autonomous, and demandresponsive service mobility vehicles, and the energy sector, with increasing usage of alternative energy sources, battery efficiency, and microgrids. In such a crucial time to achieve sustainable practices to ward off major climate change impacts, these changes across different systems need to be integrated globally. The objective of the study of mobility services and microgrids in the Sumida Ward of Tokyo, Japan is to find the optimal placement for an integrated space, referred to as Smart Hubs, for both vehicular charging and energy storage using MATSim simulation and EnergyPlus modeling methods. The findings could enlighten planners and public officials of the optimal placement of these new community spaces for both time and energy optimization of new mobility services and to change the way urban energy systems are managed and utilized.

Abstract

The simple and cost-effective method was adopted to prepare hollow 1D porous structure of g-C3N4 to generate hydrogen by photocatalysis. It plays a substantial role in efficient photocatalysis of water splitting. In general, the protonated melamine was calcined at high temperature to get 1D structure. It exhibits improvement in hydrogen evolution (2.54 mmol. g -1 .h-1 ) in contrast to bulk g-C3N4 (0.10 mmol. g-1 .h-1 ). Due to porous in nature, it has a high surface area (51.369 m2 g -1 ) in contrast to bulk sample (7.73 m2 g -1 ). Furthermore, 1D structure display low resistance against the charge transfer and have low recombination rate. These observations claiming that the hollow 1D porous structure play a crucial role to enhance photocatalytic activity.

Abstract

In addressing the challenge of climate change, smart cities are expected to play an important role in introducing renewable energy sources and improving energy efficiency while maintaining resilience against natural disasters as well as socio-economic disruptions. In this paper, we examine the innovation system of smart cities in the Greater Bay Area, with a particular attention to knowledge and technological domains, actors and their networks, and institutions surrounding the actors. The innovation system of smart cities in GBA in China mainly concerns health and medical care, transportation, logistics, agriculture, surveillance, and public safety and shows a disintegrated structure of functions provided by companies in the electric and electronic industry.