后新冠肺炎疫情时代城市的加速智能化

Governments, developers and big-tech companies have become enamoured with the possibility of the smart city: an efficient, convenient (and profitable) “smart” metropolis to help accommodate and optimize rapid urban growth. While it is tempting to wash renders of future cities with the typical smart city visions of drones, segways, and shiny reflective glass towers—the reality is that good (smart) cities incorporate a bottom-up messiness and urban vitality which is fundamental to the overall thriving of the city. In Hassell’s competition winning scheme for the Xinqiao District in Shenzhen—the design team explored the ideas that a smart and innovative city that first and foremost uphold—a place which fosters inclusivity, diversity, collaboration, and resilience. Now through times of ongoing uncertainty in the COVID-19 era, Hassell’s design team expects an even greater adoption of smart cities rhetoric as a form of necessary urban surveillance and to manage and support communities and the containment of the COVID-19—building urban resilience against big disaster events, enabling adaptive environments that can re-calibrate, reorganize, and evolve in real-time as needed. Can urban designers go beyond resilience to imagine cities which thrive and grow out of disaster events?     

High pressure–treated sorghum flour as a functional ingredient in the production of sorghum bread

In this study, the application of high-pressure processing of sorghum batters was investigated in order to evaluate the potential of pressure-treated sorghum as a gluten replacement in the production of sorghum breads. For this purpose, sorghum batters were treated at pressures from 200 to 600 MPa at 20 °C, and the microstructure was investigated using scanning electron microscopy. Furthermore, the rheological properties of the control and pressure-treated batters were determined. The results revealed weakening of the batter structure at pressures ≤300 MPa. Addition of a blocker of free thiol groups indicated that protein depolymerization played a role in this strength decrease. At pressures >300 MPa, the batter consistency increased, mainly due to pressure-induced gelatinization of starch. Furthermore, freeze-dried sorghum batters treated at 200 MPa (weakest batter) and at 600 MPa (strongest batter) were added to a sorghum bread recipe, replacing 2 and 10% of untreated sorghum flour. The results showed a delayed staling for breads containing 2% of sorghum treated at 600 MPa. However, adding 10% resulted in a low specific volume and poor bread quality. The quality of breads containing different amounts of sorghum treated at 200 MPa was not significantly different from the control bread.     

Tantalum Capacitor Separation from Waste Printed Circuit Boards with Molten Salt or Metal

Tantalum is the crucial metal of surface-mounted (SMD) tantalum capacitors. Some 50 % of the tantalum mined is consumed in its manufacture, making waste printed circuit boards (WPCBs) an excellent source of secondary tantalum. Yet, its recycling rate is less than 1 %. This paper proposes liberating SMD capacitors from WPCBs by treating them with molten metal or salt. For both processes, the epoxy encapsulation of the capacitors did not disengage from the tantalum core. Furthermore, the molten metal process appears superior to the molten salt one. The tantalum capacitors exit the pyrolysis chamber without salt adhering to them.     

3D Printing of Multifunctional Conductive Polymer Composite Hydrogels

Functional conductive hydrogels are widely used in various application scenarios, such as artificial skin, cell scaffolds, and implantable bioelectronics. However, their novel designs and technological innovations are severely hampered by traditional manufacturing approaches. Direct ink writing (DIW) is considered a viable industrial-production 3D-printing technology for the custom production of hydrogels according to the intended applications. Unfortunately, creating functional conductive hydrogels by DIW has long been plagued by complicated ink formulation and printing processes. In this study, a highly 3D printable poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)-based ink made from fully commercially accessible raw materials is demonstrated. It is shown that complex structures can be directly printed with this ink and then precisely converted into high-performance hydrogels via a post-printing freeze–thawing treatment. The 3D-printed hydrogel exhibits high electrical conductivity of ≈2000 S m⁻¹, outstanding elasticity, high stability and durability in water, electromagnetic interference shielding, and sensing capabilities. Moreover, the hydrogel is biocompatible, showing great potential for implantable and tissue engineering applications. With significant advantages, the fabrication strategy is expected to open up a new route to create multifunctional hydrogels with custom features, and can bring new opportunities to broaden the applications of hydrogel materials.     

Comparison of UV-Cl and UV-H2O2 advanced oxidation processes in the degradation of contaminants from water and wastewater: A review

Applications of advanced oxidation processes (AOPs) in water and wastewater treatment have been the subject of growing interest throughout the last decade. Although UV/hydrogen peroxide (UV-H₂O₂) is the most established technology among the UV-AOPs, UV-chlorine (UV-Cl) is emerging as a reliable and potentially more cost-effective alternative. Recent studies have indicated that UV-Cl processes may be more efficient and economically favourable for the degradation of some chemicals of emerging concern from contaminated water. Moreover, in terms of the formation of disinfection by-products (DBPs), UV-H₂O₂ seems to have no superiority over UV-Cl. This said, more investigation in the assessment of genotoxicity and cytotoxicity of DBPs is required. Additionally, more pilot-scale and full-scale studies are required to establish UV-Cl as a reliable alternative to UV- H₂O₂. This paper compares UV-Cl and UV-H₂O₂ AOPs for the degradation of intractable chemicals from water and wastewater based on the practical considerations of efficiency, cost, DBP formation, kinetics and sensitivity to water matrix variability. Finally, various modelling approaches to UV-Cl have been reviewed. This review showed that UV-Cl is superior to UV-H₂O₂ in terms of degradation efficiency and cost effectiveness and can be a robust alternative in many UV-AOPs applications.     

Looking Outside the Square: The Growth,Structure, and Resilient Two-Dimensional Surface Electron Gas of Square SnO2 Nanotubes

Nanotechnology has delivered an amazing range of new materials such as nanowires, tubes, ribbons, belts, cages, flowers, and sheets. However, these are usually circular, cylindrical, or hexagonal in nature, while nanostructures with square geometries are comparatively rare. Here, a highly scalable method is reported for producing vertically aligned Sb-doped SnO₂ nanotubes with perfectly-square geometries on Au nanoparticle covered m-plane sapphire using mist chemical vapor deposition. Their inclination can be varied using r- and a-plane sapphire, while unaligned square nanotubes of the same high structural quality can be grown on silicon and quartz. X-ray diffraction measurements and transmission electron microscopy show that they adopt the rutile structure growing in the [001] direction with (110) sidewalls, while synchrotron X-ray photoelectron spectroscopy reveals the presence of an unusually strong and thermally resilient 2D surface electron gas. This is created by donor-like states produced by the hydroxylation of the surface and is sustained at temperatures above 400 °C by the formation of in-plane oxygen vacancies. This persistent high surface electron density is expected to prove useful in gas sensing and catalytic applications of these remarkable structures. To illustrate their device potential, square SnO₂ nanotube Schottky diodes and field effect transistors with excellent performance characteristics are fabricated.     

Optimized massively parallel solving of N-Queens on GPGPUs

Continuous evolution and improvement of GPGPUs has significantly broadened areas of application. The massively parallel platform they offer, paired with the high efficiency of performing certain operations, opens many questions on the development of suitable techniques and algorithms. In this work, we present a novel algorithm and create a massively parallel, GPGPU-based solver for enumerating solutions of the N-Queens problem. We discuss two implementations of our algorithm for GPGPUs and provide insights on the optimizations we applied. We also evaluate the performance of our approach and compare our work to existing literature, showing a clear reduction in computational time.