The field of heterogeneous photocatalysis has expanded rapidly in the last four decades, having undergone various evolutionary phases related to energy and the environment. The two most significant ...applications of photocatalysis are geared toward solar water splitting and the purification of air and water. Notably, the interdisciplinary nature of the field has increased significantly, incorporating semiconductor physics, surface sciences, photo and physical chemistry, materials science, and chemical engineering. Whereas this forms the basis on which the field continues to grow, adequate bridging of multidisciplinary knowledge remains essential. By recalling some of the classical fundamentals of photocatalysis, this Perspective provides contemporary views on heterogeneous photochemical conversion, encompassing charge transport characteristics, radical chemistry and organic degradation mechanisms, photocatalyst design, and photoreactor engineering.
Bioinspired nanotopography artificially fabricated on titanium surfaces offers a solution for the rising issue of postoperative infections within orthopedics. On a small scale, hydrothermal etching ...has proven to deliver an effective antimicrobial nanospike surface. However, translation to an industrial setting is limited by the elevated synthesis temperature (150 °C) and associated equipment requirements. Here, for the first time, we fabricate surface nanostructures using comparatively milder synthesis temperatures (75 °C), which deliver physicochemical properties and antimicrobial capability comparable to the high-temperature surface. Using a KOH etchant, the simultaneous formation of titania and titanate crystals at both temperatures produces a one-dimensional nanostructure array. Analysis indicated that the formation mechanism comprises dissolution and reprecipitation processes, identifying the deposited titanates as hydrated layered tetra-titanates (K2Ti4O9·nH2O). A proposed nanospike formation mechanism was confirmed through the identification of a core and outer shell for individual nanostructures, primarily comprised of titanates and titania, respectively. Etching conditions dictated crystalline formation, favoring a thicker titanate core for nanorods under higher synthesis temperatures and etchant concentrations. A bactericidal investigation showed the efficacy against Gram-negative bacteria for a representative low-temperature nanosurface (34.4 ± 14.4%) was comparable to the higher temperature nanosurface (34.0 ± 17.0%), illustrating the potential of low-temperature hydrothermal synthesis. Our results provide valuable insight into the applicability of low-temperature etching protocols that are more favorable in large-scale manufacturing settings.
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•Alloyed NiCo catalysts outperform monometallic Ni and Co in activity and stability.•Ni is more selective than Co towards CH4 cracking and CO2 activation.•Co is more selective than Ni ...toward the Boudouard Reaction.
Nickel and cobalt-based catalysts are very promising candidates for the dry reforming of methane, but their role in regulating catalyst selectivity has thus far been overlooked. Here we report the significant impact that catalyst selectivity has on the performance of Ni and Co catalysts for the dry reforming of methane. The role of Ni and Co in defining catalyst selectivity was examined via in-depth investigations into the tendency of catalysts towards the Boudouard, methane cracking and reverse water gas shift side reactions. Decoupling the side reactions demonstrated that Co deposits have a high affinity for the removal of carbon species via oxidation, while Ni is more active towards CH4 decomposition. Thereby superior catalytic performance is accessed via a combination of the high activity of Ni towards CH4 with the stabilising effect and carbon-resistance of Co. Characterisation of the materials illustrated the formation of well-dispersed NiCo alloys on the FSP-alumina, with the resulting strong bimetallic interactions fuelling enhanced catalytic performance via suppression of catalyst selectivity of Co towards the Boudouard reaction and Ni towards methane cracking.
Recent advances in traffic monitoring systems have made real-time traffic velocity data ubiquitously accessible for drivers. This paper develops a traffic data-enabled predictive energy management ...framework for a power-split plug-in hybrid electric vehicle (PHEV). Compared with conventional model predictive control (MPC), an additional supervisory state of charge (SoC) planning level is constructed based on real-time traffic data. A power balance-based PHEV model is developed for this upper level to rapidly generate battery SoC trajectories that are utilized as final-state constraints in the MPC level. This PHEV energy management framework is evaluated under three different scenarios: 1) without traffic flow information; 2) with static traffic flow information; and 3) with dynamic traffic flow information. Numerical results using real-world traffic data illustrate that the proposed strategy successfully incorporates dynamic traffic flow data into the PHEV energy management algorithm to achieve enhanced fuel economy.
Optical filters can be used to increase solar conversion efficiency in hybrid photovoltaic/thermal (PV/T) collectors by partitioning incident light into two spectra: one desirable for direct ...electrical conversion and one for thermal collection. This article is the first to present both modeled and experimental results for a spectrally-tailorable, multi-particle nanofluid filter positioned between a concentrated light source and a silicon cell. The nanofluid is composed of suspended core–shell silver-silica (Ag–SiO2) nanodiscs and carbon nanotubes (CNTs) in water. The core–shell particles were specifically synthesized and designed to absorb the majority of the visible spectrum, while transmitting the light which corresponds to the PV cell. The silver nanodiscs strongly absorb visible light with minimal scattering, whereas the silica shell maintains the shape and absorption spectrum of the silver cores. Alternatively, low-concentration carbon nanotube (CNT) solutions were used to enhance absorption (particularly of ultra-violet light) and to provide a comparison for selective filters versus broadband absorbers. Varying dilutions of the Ag–SiO2 nanofluid are compared to solutions diluted with dispersed CNTs. The CNTs enhance the heating rate of the nanofluid with the caveat of non-selective light absorption, which reduces the electrical output. Ag–SiO2 nanofluids (0.026wt%) increased combined efficiencies by 30% compared to the base fluid filter alone. For a small additional cost of <$1/L of nanofluid, the developed system represents a highly efficient hybrid generator which can be dynamically tailored to meet variable thermal energy and electricity prices.
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•Selectively absorbing nanofluids were fabricated for hybrid PV/thermal collectors.•Core–shell silver-silica nanodiscs and carbon nanotubes were suspended in water.•Temperature and photocurrent were measured for fluid filters and silicon PV.•A merit function was used to evaluate the combined power output for nanofluids.•Optical efficiencies of up to 58% can be achieved for <$1/L of nanofluid.
This article examines how class, consumerism, and employment influence beliefs of an idealized digital world in marginalized communities. I recount 24 months of ethnographic and institutional ...observation in a non-governmental organization that promoted the concept of “utopia digital” (digital utopia in Portuguese) in Rio de Janeiro’s favelas (shantytowns). This corporate-funded non-governmental organization employed members of Brazil’s traditional middle class and promoted the liberating potentials of digital inclusion to members of a “New Middle Class” made up of 35 million “previously poor” Brazilians. Interviews with middle-class employees reveal how ideas of digital utopia act as a code for corporate efforts to encourage consumerism among the New Middle Class and bolster employment opportunities for members of Brazil’s traditional middle class. Reflecting on informal conversations, I also highlight a middle-class “crime talk” that frames the favela as an inherently violent place and, in contrast to their inclusionary work related to digital utopia, encourages non-governmental organization workers to physically avoid favela space. I use Zygmunt Bauman’s discussion of an “active” or “hunter” utopia as an ethnographic lens to discuss the practical and everyday experiences of technological inclusion in classed settings. By describing digital utopias as actively shaped by everyday understandings of urban exclusion and privilege, this article provides an ethnographic framework for decoding the socially reproductive nature of class-inflected consumer interventions in marginalized communities.
This paper presents a new battery state-of-charge (SOC) estimation method for lithium-ion batteries (LIBs) based on a nonlinear fractional model with incommensurate differentiation orders. A ...continuous frequency distributed model is used to describe the incommensurate fractional system. A Luenberger-type observer is designed for battery SOCestimation. The observer gain that can stabilize the zero equilibrium of the estimation error system is derived by Lyapunov's direct method. The proposed SOC observer is examined using the real-time experimental data of LIBs. The robustness of the observer under different test conditions, including different aging levels, different driving cycles, and different cells, is also presented.
This paper examines the problem of optimally splitting driver power demand among the different actuators (i.e., the engine and electric machines) in a plug-in hybrid electric vehicle (PHEV). Existing ...studies focus mostly on optimizing PHEV power management for fuel economy, subject to charge sustenance constraints, over individual drive cycles. This paper adds three original contributions to this literature. First, it uses stochastic dynamic programming to optimize PHEV power management over a distribution of drive cycles, rather than a single cycle. Second, it explicitly trades off fuel and electricity usage in a PHEV, thereby systematically exploring the potential benefits of controlled charge depletion over aggressive charge depletion followed by charge sustenance. Finally, it examines the impact of variations in relative fuel-to-electricity pricing on optimal PHEV power management. The paper focuses on a single-mode power-split PHEV configuration for mid-size sedans, but its approach is extendible to other configurations and sizes as well.
Colletotrichum tanaceti is an emerging foliar fungal pathogen of commercially grown pyrethrum (Tanacetum cinerariifolium). Despite being reported consistently from field surveys in Australia, the ...molecular basis of pathogenicity of C. tanaceti on pyrethrum is unknown. Herein, the genome of C. tanaceti (isolate BRIP57314) was assembled de novo and annotated using transcriptomic evidence. The inferred putative pathogenicity gene suite of C. tanaceti comprised a large array of genes encoding secreted effectors, proteases, CAZymes and secondary metabolites. Comparative analysis of its putative pathogenicity gene profiles with those of closely related species suggested that C. tanaceti likely has additional hosts to pyrethrum. The genome of C. tanaceti had a high repeat content and repetitive elements were located significantly closer to genes inferred to influence pathogenicity than other genes. These repeats are likely to have accelerated mutational and transposition rates in the genome, resulting in a rapid evolution of certain CAZyme families in this species. The C. tanaceti genome showed strong signals of Repeat Induced Point (RIP) mutation which likely caused its bipartite nature consisting of distinct gene-sparse, repeat and A-T rich regions. Pathogenicity genes within these RIP affected regions were likely to have a higher evolutionary rate than the rest of the genome. This "two-speed" genome phenomenon in certain Colletotrichum spp. was hypothesized to have caused the clustering of species based on the pathogenicity genes, to deviate from taxonomic relationships. The large repertoire of pathogenicity factors that potentially evolve rapidly due to the plasticity of the genome, indicated that C. tanaceti has a high evolutionary potential. Therefore, C. tanaceti poses a high-risk to the pyrethrum industry. Knowledge of the evolution and diversity of the putative pathogenicity genes will facilitate future research in disease management of C. tanaceti and other Colletotrichum spp.
Unique CO2 methanation catalysts comprising bimetallic Ni–Rh nanoalloy/3DOM LaAlO3 have been successfully prepared via a poly(methyl methacrylate) microsphere colloidal crystal-templating route, ...followed by the in situ growth of Ni nanoparticles (NPs). Here, we show that unlike traditional Ni particles deposited on a perovskite support, the exsolution of Ni occurs on both the external and internal surface of the porous perovskite substrate, leading to a strong metal–support interaction. Owing to the exsolution of Ni and the formation of Ni–Rh nanoalloys, a 52% enhancement in the methanation turnover frequency was obtained over the Ni–Rh/3DOM LaAlO3 13.9 mol/(mol h) compared to Rh/3DOM LaNi0.08Al0.92O3 9.16 mol/(mol h) before reduction treatment. The results show that the low-temperature reducibility, rich surface adsorbed oxygen species, and basic sites of the catalyst greatly improve its activity toward CO2 methanation. The hierarchically porous structure of the perovskite support provides a high dispersion of bimetallic Ni–Rh NPs.
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