This study presents a novel process and manufacturing system for the fabrication of Electric Double-Layer Capacitors (EDLCs) as energy storage devices. It shows an approach for printing multilayer EDLC components using 3D printing technology. This process allows layers of activated carbon (AC) slurry, gel electrolyte, and composite solid filaments to be printed with high precision. The study describes the detailed process of deposition of the AC and gel electrolyte using the dual nozzle system. The performance of the flexible EDLCs manufactured by 3D printing in a rectilinear infill pattern has been investigated. It describes the energy storage performance of the printed supercapacitors in relation to the differences in thickness of the AC printed layers and the differences in density of gel electrolyte. A supercapacitor based on printed AC and composite materials displays a specific capacitance of 38.5 mF g⁻¹ when measured at a potential rate change of 20 mV s⁻¹ and a current density of 0.136 A g⁻¹. The highest energy density value for the flexible EDLC was 0.019 Wh kg⁻¹ and power density of 165.0 W kg⁻¹ in 1.6 M H₂SO₄/PVA gel electrolyte.

With the growing implementation of smart city projects and the significance of the research problem related to effective design thinking, the opinion of the ordinary citizens have become very relevant and contemporary. The current paper presents a quantitative empirical study focused on the attitudes towards and the readiness to accept smart cities in the specific context of Qatar. The study employs a survey questionnaire as a data collection tool. The survey is distributed online among a sample of 40 respondents from Qatar, including both residents and non-residents of smart cities in the country. Even though the sample is not representative of the Qatari population, the present study provides preliminary findings and fundamental insights into this novel topic in a specific socio-economic context. The major findings of the study uncovered that the respondents show quite positive attitudes toward diverse aspects related to smart economy, smart people, smart governance, smart mobility, smart environment, and smart living, as well as significant readiness to accept this lifestyle. However, the respondents demonstrate concerns related to the privacy and security of the people living in smart cities. The superiority of fundamental aspects of life like housing and healthcare in smart cities compared to conventional ones are also questioned by the respondents.

In this work, a novel wire-shaped supercapacitor based on nylon yarn with a high specific capacitance and energy density was developed by designing an asymmetric configuration and integrating pseudocapacitive materials for both electrodes. The nylon/Ag/MnO₂ yarn was prepared as a positive electrode by electrochemically depositing MnO₂ on a silver-paste-coated nylon yarn. Additionally, PPy was prepared on nylon/Ag yarn by chemical polymerization firstly to enlarge the surface roughness of nylon/Ag, and then the PPy could be easily coated on the chemically polymerized nylon/Ag/PPy by electrochemical polymerization to obtain a nylon/Ag/PPy yarn-shaped negative electrode. The wire-shaped asymmetric supercapacitor (WASC) was fabricated by assembling the nylon/Ag/MnO₂ electrode, nylon/Ag/PPy electrode and PAANa/Na₂SO₄ gel electrolyte. This WASC showed a wide potential window of 1.6 V and a high energy density varying from 13.9 to 4.2 μWh cm⁻² with the corresponding power density changing from 290 to 2902 μW cm⁻². Meanwhile, because of the high flexibility of the nylon substrate and superior adhesion of active materials, the WASC showed a good electrochemical performance stability under different bending conditions, suggesting its good flexibility. The promising performance of this novel WASC is of great potential for wearable/portable devices in the future.