BackgroundSynchrotron radiation experimental methods have unique advantages in studying the structure and physical properties of materials, but it is a challenge for many experimental methods to ...achieve synchrotron radiation in situ high temperature conditions, especially above 2 000 K. Laser heating methods can achieve rapid, micro-region extreme high temperature conditions, and have become an important tool for the study of high temperature physical properties.PurposeThis study aims to develop a portable laser heating device for Shanghai Synchrotron Radiation Facility (SSRF) in situ experiments in the field of extreme high temperature research, such as high entropy alloys, turbine blades, aviation materials, etc.MethodsA 100 W continuously tunable near-infrared fiber laser was used as the heating souce, the sample was heated up by laser through the focusing lens and generated thermal radiation. The radiation spectrum was collected through the spectral collection focusing lens and measured by spectrometers.
Deep-sea toxicology is essential for deep-sea environmental impact assessment. Yet most toxicology experiments are conducted solely in laboratory settings, overlooking the complexities of the ...deep-sea environment. Here we carried out metal exposure experiments in both the laboratory and in situ, to compare and evaluate the response patterns of Gigantidas platifrons to metal exposure (copper Cu or cadmium Cd at 100 μg/L for 48 h). Metal concentrations, traditional biochemical parameters, and fatty acid composition were assessed in deep-sea mussel gills. The results revealed significant metal accumulation in deep-sea mussel gills in both laboratory and in situ experiments. Metal exposure could induce oxidative stress, neurotoxicity, an immune response, altered energy metabolism, and changes to fatty acid composition in mussel gills. Interestingly, the metal accumulating capability, biochemical response patterns, and fatty acid composition each varied under differing experimental systems. In the laboratory setting, Cd-exposed mussels exhibited a higher value for integrated biomarker response (IBR) while in situ the Cu-exposed mussels instead displayed a higher IBR value. This study emphasizes the importance of performing deep-sea toxicology experiments in situ and contributes valuable data to a standardized workflow for deep-sea toxicology assessment.
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•Deep-sea mussels significantly accumulated metals from their surroundings.•Metal exposure affected conventional biochemical indexes in deep-sea mussels.•Metal exposure changed fatty acid composition of deep-sea mussel gills.•Deep-sea mussels responded differently under in situ and laboratory systems.•In situ exposure approach is important for deep-sea environmental assessment.
In situ straining experiments were carried out in pure tungsten in order to study the geometry and kinetics of glide of dislocations as a function of stress and temperature. For tensile axes ...different from , screw dislocations move by a combination of steady and jerky motion in planes which cannot be identified unambiguously. For a tensile axis close to , however, screw dislocations have a much jerkier motion with jumps over large distances, in {112} planes exactly but only in the twinning direction, and in {123} planes. This involves a strong violation of the Schmid law, in agreement with slip line observations reported in the 60's by different authors. Jerky {112} slip is combined with a more classical steady motion in planes close to {110}, but the proportion of steady motion decreases rapidly to zero at decreasing temperature, which leads to a gradual transition between the two mechanisms. These results account for the specific mechanical properties measured in case of a straining axis. They also bring new elements to understand the discrepancy between theoretical and experimental stress values at low temperatures. Indeed, like in Fe, local stress values as a function of temperature and dislocation velocity do not obey to the classical rules of thermodynamics, in agreement with possible quantum effects.
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•Diurnal and dynamic energy efficiency metrics of photovoltaic façade were developed.•Design of photovoltaic facade and PCM inserts were optimized and validated.•Regression models of ...metrics were made based on heating season in-situ experiments.•Energy balance in heating season for different climate conditions is presented.
High energy efficiency, energy autonomy, and improved living conditions are basic requirements of sustainable buildings. Advanced building envelope structures can provide these requirements. In the present paper, multipurpose façade structure designed as semi-transparent modular building-integrated photovoltaic façade with a forced ventilated cavity and enhanced heat storage capacity, using encapsulated phase change inserts installed on inner glass pane of photovoltaic module and on building envelope, is evaluated. The design of the façade structure, including simultaneous optimization of photovoltaic cell-packing factor, phase change material inserts properties, and heat transfer by convection in air gap, was based on transient modeling. A 60% photovoltaic cell-packing factor enables the highest overall energy efficiency, while phase change material inserts on the inner glass pane of photovoltaic module have no impact on diurnal photovoltaic cell efficiency. However, a phase change material layer installed on the envelope decreases the diurnal heat losses by half at solar radiation of 2200 Wh/m2 day. The energy performance of an optimized modular structure was determined via in-situ experiments; the data were used for developing dynamic approximation models of energy efficiency indicators. It was found that multiple regression models with interactions and past values can predict dynamic responses with sufficient accuracy. Depending on the heating season’s climate conditions, the developed semi-transparent modular building-integrated photovoltaic façade decreases the energy needs 40% to 55% in comparison to the reference façade with solar energy utilization efficiency in the range between 44% and 63%. This proves that such structures can contribute to fulfilling of requirements of sustainable buildings.
Developing efficient catalysts for catalytic oxidation of toluene at low temperatures is challenging. Herein, the OH groups and oxygen vacancies are introduced into CeO2 by methanol modification and ...applied in catalytic oxidation of toluene. CeO2-T-M, one of the modified CeO2, displays the greatest catalytic activity for toluene oxidation with T90 of 235 oC. In situ characterizations and theoretical calculations show that abundant OH groups and oxygen vacancies on the CeO2-T-M are well correlated with the catalytic activity. The OH groups facilitate the adsorption and activation of gaseous oxygen into adsorbed active oxygen species (O22-) and lattice oxygen (O2-) over oxygen vacancies. And the toluene and key intermediates (benzyl alcohol, benzaldehyde, benzoate, and maleic anhydride) are more easily adsorbed and oxidized on CeO2-T-M. Meanwhile, the consumed OH groups will be regenerated with activated lattice oxygen by dehydrogenation, thus the catalytic activity and stability for toluene oxidation are enhanced over modified CeO2.
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•Methanol, one of the VOCs in the exhaust gas is employed for modification over CeO2 catalysts and is simultaneously degraded.•The coexistence of OH groups and oxygen vacancies on modified CeO2 improves the catalytic oxidation performance of toluene.•The promotion effect of OH groups and oxygen vacancies are identified by multiple in situ spectroscopy and DFT calculations.
The RootProf computer program applies multivariate model‐free analysis to crystallographic data and to any x, y experimental data in general. It has been enhanced with several new features, including ...a graphical user interface, multithreading implementation and additional pre‐processing options. The program also includes novel qualitative analysis methods, such as semiquantitative estimates derived from principal component analysis (PCA) and restrained PCA to extract the diffraction signal from active atoms. Additional quantitative analysis methods have been included, involving the combination of different datasets or the application of the standard addition method as well as tools for crystallinity analysis, kinetic analysis and extraction of free crystal cell parameters from a pair distribution function profile. The ROOT data analysis framework supports the program and can be installed on the current major platforms such as Windows, Linux and Mac OSX with detailed user documentation included. Applications of the new developments are presented and discussed in the paper, and related command files are provided as supporting information.
New features of the RootProf program for model‐free analysis of unidimensional profiles are presented and discussed.
Nanostructured adhesive hairs on the feet of spiders are responsible for strong adhesion, enabling the animals to walk vertically and upside down. In article number 2002758, Clemens F. Schaber, ...Martin Müller, and co‐workers use scanning nanofocus X‐ray scattering under force control to elucidate the mechanism of alignment and consequently strong attachment of the nanostructures to a glass surface. The spider attachment system is a promising model for the development of powerful residue‐free dry adhesives.
The interplay between the diffusion-controlled dynamics of a solidification front and the trajectory of a grain boundary groove at the solid-liquid interface is studied by means of thin-sample ...directional solidification experiments of a transparent alloy, and by numerical simulations with the phase-field method in two dimensions. Here, we find that low-angle grain boundaries (subboundaries) with an anisotropic interfacial free energy grow tilted at an angle θt with respect to the temperature gradient axis. θt remains essentially equal to its value imposed at equilibrium as long as the solidification velocity V remains low. When V increases and approaches the cellular instability threshold, θt decreases, and eventually vanishes when a steady-state cellular morphology forms. The absence of mobility of the subboundary in the solid is key to this transition. These findings are in good agreement with a recent linear-stability analysis of the problem.
Electrocatalysis is at the heart of a broad range of physicochemical applications that play an important role in the present and future of a sustainable economy. Among the myriad of different ...electrocatalysts used in this field, nanomaterials are of ubiquitous importance. An increased surface area/volume ratio compared to bulk makes nanoscale catalysts the preferred choice to perform electrocatalytic reactions. Bragg coherent diffraction imaging (BCDI) was introduced in 2006 and since has been applied to obtain 3D images of crystalline nanomaterials. BCDI provides information about the displacement field, which is directly related to strain. Lattice strain in the catalysts impacts their electronic configuration and, consequently, their binding energy with reaction intermediates. Even though there have been significant improvements since its birth, the fact that the experiments can only be performed at synchrotron facilities and its relatively low resolution to date (∼10 nm spatial resolution) have prevented the popularization of this technique. Herein, we will briefly describe the fundamentals of the technique, including the electrocatalysis relevant information that we can extract from it. Subsequently, we review some of the computational experiments that complement the BCDI data for enhanced information extraction and improved understanding of the underlying nanoscale electrocatalytic processes. We next highlight success stories of BCDI applied to different electrochemical systems and in heterogeneous catalysis to show how the technique can contribute to future studies in electrocatalysis. Finally, we outline current challenges in spatiotemporal resolution limits of BCDI and provide our perspectives on recent developments in synchrotron facilities as well as the role of machine learning and artificial intelligence in addressing them.
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