58622 research outputs found
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Convenient Production of Photothermal Recycling Phosphorescent Materials from Cellulose and Lignin
Get PDFDeveloping recyclable room-temperature phosphorescent (RTP) films using ultrafast fabrication techniques remains a critical yet challenging objective. With this research, we developed an RTP film (Cell-Lig) through ethanol-induced phase transition, achieving solid film formation within 1 s from ionic liquid (1-butyl-3-methylimidazolium chloride, [Bmim]Cl) solutions of cellulose and lignin. The phase transition also generated a confined rigid environment for Cell-Lig, activating thickness- and temperature-dependent green RTP emission from the incorporated lignin. Furthermore, red afterglow emission using an energy transfer mechanism was realized by incorporating rhodamine B (RhB). The inherent photothermal activity of lignin endowed Cell-Lig with easy recyclability using light-controlled phase transitions. Under irradiation, photothermal evaporation of residual ethanol triggered liquefaction (solid-to-liquid transition), while ethanol reintroduction facilitated instantaneous hardening. Remarkably, the initial RTP performance was maintained over six recycling cycles. Capitalizing on these attributes, Cell-Lig was successfully used for advanced coating and security applications.</p
Alkali-resistant and aging-tolerant NO<sub>x</sub> reduction over self-regulated anti-poisoning catalysts for biodiesel vehicle exhaust purification
Get PDFMaintaining the ammonia selective catalytic reduction efficiency of catalysts in the co-presence of alkaline metals and high-temperature water vapor among biodiesel vehicle exhaust purification remains a great challenge at present. Here, alkali-resistant and aging-tolerant NOx reduction over self-regulated anti-poisoning catalysts for biodiesel vehicle exhaust purification had been innovatively demonstrated. TiO2 pillared natural montmorillonite clays with adequate alkaline metal trapping sites and thermal-stable layered silicate framework was applied to support CeO2 and WO3 to obtain a novel NH3-SCR catalyst that demonstrated outstanding alkaline resistance even under the superimposed effects of hydrothermal aging. It was revealed that Si-O-Si sites among the montmorillonite support could effectively trap the alkaline metal poisons into the layered framework of montmorillonite clays, which can prevent the active component from being damaged and preserve the distinctive layered structure in the presence of high-temperature steam, thus exhibiting remarkable alkaline metal resistance and stronger hydrothermal stability than commercial V2O5-WO3/TiO2 catalysts. This work paves a way for the development of low temperature and high efficiency denitrification catalysts with alkaline metal resistance and hydrothermal aging tolerance for biodiesel vehicle exhaust purification.</p
Desired and Feared Identities and Their Role in Occupational Identity Regulation
Get PDFThis paper extends theory by showing how occupational identity regulation operates jointly through both desired and feared identities which, in combination, enforce normative control. Taking a narrative identity perspective and drawing on an ethnographic and interview-based study of veterinarians, we make three principal contributions to our understanding of identity regulation. First, we explain how, in high surveillance contexts, occupational members construct not just positively valenced desired identities but also negatively valenced feared identities, and how feared identities are antagonistic foils to desired ones that enhance their appeal. Second, we analyse how self-discipline is exerted through dual processes of self-examination: prideful talk that affirms desired identities and guilt-ridden talk which casts doubt on their attainment and spurs auto-correction. Third, we demonstrate how conformist identity work which (re)produces occupational identities through desire and fear reduces people's scope for resistance. This research highlights identity work that is non-supportive of the (desired) self and how an appreciation of feared in addition to desired identities is vital to understand fully the tensional nature of occupational selves.</p
Numerical evaluation of the Kirchhoff--Helmholtz integral outside a sphere
Get PDFA method is presented for the fast evaluation of the transient acoustic field generated outside a spherical surface using surface data on the sphere. The method employs Lebedev quadratures, which are optimal integration on the sphere, and Lagrange interpolation and differentiation in an advanced time algorithm for the evaluation of the transient field. Numerical testing demonstrates that the approach gives near machine-precision accuracy and a speed-up in evaluation time, which depends on the order of quadrature rule employed but breaks even with direct evaluation at a number of field points about 1.15 times the number of surface quadrature nodes, thus making the method an efficient means of evaluating the field generated by a large number of sources.</p
Synergistic catalytic removal of NO<sub>x</sub> and chlorinated aromatics via atomically dispersed asymmetric Mn-O-Ce sites on montmorillonite
Get PDFThe synergistic catalytic removal of nitrogen oxides (NOx) and chlorinated volatile organic compounds (CVOC) is in significant demand from both ecological and economic perspectives. Breaking the trade-off between synergistic catalytic activity and selectivity is a big challenge. In this study, we developed a catalyst named MnCeOx/MMT-Ti, which features an atomically dispersed MnCeOx supported on montmorillonite. It exhibited superior performance from 260 to 330 °C, achieving over 80 % conversion of NOx and chlorobenzene (CB), as well as over 80 % selectivity for N2 and CO2. Atomically dispersed asymmetric Mn-O-Ce sites were constructed and evidenced. The isolated asymmetric Mn-O-Ce sites in MnCeOx/MMT-Ti stimulated exceptional O2 adsorption and activation, facilitating CB oxidation through a variant Mars-van Krevelen mechanism while improving the N2 selectivity of NOx reduction. In addition, the abundant Brønsted acid sites from montmorillonite ensured the Cl-resistance and high stability of the catalyst. This study presents a novel approach for the synergistic removal of NOx and VOCs via tailoring atomically dispersed active sites of synergistic catalysts composed of complex oxides.</p
Investigating the Impact of Deformable, Movable, and Rigid Surfaces on Force-Input Interactions
Get PDFThe force modality fundamentally transforms the interaction space of traditional touch input. When paired with compliant devices, which deform under force and provide immediate haptic feedback, there is potential to enhance user interactions significantly. However, the effects of compliance on force-input remain under-explored, with limited understanding of their full potential. This article presents the first systematic investigation of the impact of deformable, movable, and rigid surfaces on user performance and experience through three rigorous studies (each N = 28). The results reveal previously unreported effects, including (1) higher maximum comfortable forces on deformable surfaces, (2) user preference for soft and deformable surfaces over rigid surfaces, and (3) improved ability to maintain force input on softer surfaces. These results highlight the benefits of compliant surfaces, contrasting with the dominant use of force-input on rigid devices. These findings guide researchers and designers in optimizing user experience and performance of force-input interactions.</p
Portable electrochemical detection of salivary cortisol in self-driven microfluidic chip designed for trace liquid mixing
Get PDFThe real-time detection of cortisol in saliva is of great significance for the early non-invasive diagnosis of related diseases. In this work, a segmented micro-liquid mixing structure was fabricated using various passive valves, which can achieve the mixing of different liquids ranging from 0.3 to 0.5 μL, enabling efficient binding between cortisol antigens and antibodies. Moreover, by incorporating a capillary pump, self-driven liquid mixing can be accomplished without an external power supply. Electrochemical sensors for IgG and cortisol were prepared using the immunological sandwich method. Through the antibody-antigen-antibody sandwich structure, highly specific detection of IgG and cortisol within the range of 0.1–200 ng/mL was achieved, and the corresponding portable DPV detection circuit was designed and manufactured. By integrating the microfluidic chip, the sensor, and the miniaturized detection circuit into a POCT device, automatic detection of saliva cortisol can be achieved within 40–50 min. By adjusting the antibody modification in the sensor, the application of this physiological fluid POCT device can be expanded, and it may provide some inspiration for the development of portable non-invasive health management devices.</p
High-Order Mode Harmonic Investigation in Electromagnetic Noise Analysis of Outer-Rotor In-Wheel Motors Using Multiple Basic Slot/Pole Combinations
Get PDFElectromagnetic (EM) noise radiated by the rotor is a key point in the analysis of outer-rotor (OR) in-wheel motors (IWMs). Previous research only focused on the EM forces while lacking enough insight into the harmonic characteristics of mode shapes. This paper highlights the impact of the high-order mode harmonics of OR-IWMs caused by the use of multiple basic slot/pole combinations. Focusing on a 72-slot/80-pole OR-IWM, the coupled-field finite element analysis (FEA), consisting of a 2-dimensional EM model and a 3-dimensional structural model of the rotor assembly, is built to predict the main EM noises. It is found that identifying the primary EM forces causing the noises is challenging because the existing force modulation theory oversimplifies the spatial characteristics of modes. An analytical model is proposed to analyze the mode shapes of OR-IWMs in terms of mode harmonics. The investigation reveals that the unsymmetric OR structure can generate high-order mode harmonics within modes that are traditionally considered to be low-order. Furthermore, the equivalent radiated power levels generated by the high-order mode harmonics are assessed, and the primary contributing force harmonics are determined. The prototype of the studied IWM is manufactured, and sound pressure is measured for validation.</p
Biochemical and structural insights into GMHpaB:A thermostable 4-Hydroxyphenylacetate-3-monooxygenase with dual cofactor versatility
Get PDF4-Hydroxyphenylacetate-3-monooxygenase from the thermophilic bacterium Geobacillus mahadii Geo-05 catalyzes the hydroxylation of 4-hydroxyphenylacetate (4-HPA) to 3,4-dihydroxyphenylacetate (3,4-DHPA), marking the initial step of the 4-HPA degradation pathway. This enzyme comprises of two components: an oxygenase and reductase. In this study, the gene encoding the oxygenase component, GMHpaB was successfully cloned, overexpressed in Escherichia coli BL21 (DE3) and purified to homogeneity. Purified GMHpaB was shown to bind reduced chromogenic cofactors, evidenced by maximal absorbance peaks at 375 nm. GMHpaB is optimally active at 55 °C and demonstrates thermostability, retaining 96 % of its catalytic activity after 30 min of incubation at its optimum temperature. Furthermore, GMHpaB displays versatility, showing high enzymatic activity with both FMN and FAD as cofactors, with relative activity increases by 250 % and 383 %, respectively, compared to the cofactor-free control. The overall fold classifies GMHpaB as group D flavin-dependent monooxygenase, but distinct loop conformations set it apart from homologs within the group. Notably, residue Glu212, positioned on the substrate binding loop of GMHpaB plays a critical role in anchoring and stabilizing the flavin binding loop, potentially contributing to the enzymes dual cofactor compatibility. These biochemical and structural insights lay the groundwork for future applications, particularly in high-temperature biocatalysis.</p
Revalorization of Swedish Iron Ore Mine Tailings as Supplementary Cementitious Material through Mechanochemical Activation
Get PDFThe mining industry plays a crucial role in the economic development of many nations, but it also generates substantial waste, mainly in the form of mine tailings, which are commonly stored in dams, causing often environmental concerns. To address this issue, innovative methods are being explored for reprocessing and reutilizing these side streams. This study focuses on applying mechanochemical activation (MCA) to treat iron ore mine tailings from Kiruna, Sweden, transforming them into supplementary cementitious materials (SCMs). The MCA process resulted in extensive amorphization of the main crystalline mineral phases such as phlogopite, feldspars, apatite, and hematite. The enhanced pozzolanic activity after MCA treatment was confirmed through the strength activity index (SAI), Frattini test and R3 method. This case study highlights the significant potential of mechanochemical treatment in revalorizing iron ore mine tailings, contributing to their sustainable utilization and mitigating the negative environmental impact associated with these waste materials.</p
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