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Depositional and diagenetic evolution of the Lower Eocene homoclinic-ramp carbonates (a paradigm from the Salt Range, Pakistan) : sequence stratigraphic, petrographical, diagenetic, and geochemical attributes
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Dynamics of nitrergic system activation in the rat brain provoked by experimentally induced seizures
Get PDFLimiting the aging process of spinel-based Li-ion cells by cathode sulfur doping
No full textThe degradation of stoichiometric lithium-manganese spinel is a critical concern in the longevity and efficiency of eco-friendly, cheap lithium-ion batteries. The complex mechanisms of degradation, involving Jahn-Teller distortion of , as well as dissolution, are well-known to be accelerated by reactive species like HF. This study explores sulfur substitution into the LMO’s oxygen sublattice as a targeted approach to mitigate these aging factors. The properties and stability in the electrochemical cell of the S-doped LMO were investigated and compared to unmodified LMO using electrothermal atomic absorption spectrometry, X-ray photoelectron spectroscopy, X-ray powder diffraction, scanning and transmission electron microscopy as well as galvanostatic charge/discharge tests and electrochemical impedance spectroscopy. The sulfur doping was found to significantly increase the structural stability of the spinel and enhance the performance of the cells. These improvements were found to be caused by sulfur, which limited passive manganese dissolution and stretched the spinel structure diminishing diffusion constraints and reducing the susceptibility to mechanical strains. Furthermore, the S-doping was found to enhance both the passivation layer stability and PVDF binder durability. Although a full understanding of sulfur’s role in the sipenl-based cell aging process remains intricate, the findings affirm its role in limiting the degradation of the , especially under severe working conditions. These insights into sulfur doping open new avenues for developing more robust and environmentally friendly LMO-based materials for large-scale battery systems
Comparison of greenness and whiteness of selected mechanochemical and solution-based reactions using a new RGBsynt model
Get PDFIn analytical chemistry, the idea of assessing the “whiteness” of a method, which refers to the RGB model used in colour coding, has gained significant popularity in recent years. Whiteness represents the overall evaluation, which includes greenness (environmental impact) and functional features, represented by redness (analytical efficiency), and blueness (practicality). This work presents the first whiteness assessment model dedicated to chemical synthesis, called “RGBsynt”, inspired by the metrics used in analytics. The assessment may be applied to a set of 2–10 methods, described by parameters such as yield, product purity, E-factor, ChlorTox, time-efficiency and energy demand, which refer to the three primary colours. The model is implemented in an easy-to-use Excel spreadsheet where users input the values of the mentioned parameters, and then data analysis, evaluation and results visualization are carried out fully automatically. The RGBsynt model was employed to compare 17 solution-based procedures for O- and N-alkylation, nucleophilic aromatic substitution, and N-sulfonylation of amines with their corresponding 17 mechanochemical alternatives. The selection of synthesis processes was preceded by a thorough literature review to ensure representative examples and reliable comparison of methods. The evaluation results clearly indicate the superiority of mechanochemistry, both in reducing environmental impact (greenness), and in overall potential (whiteness). The RGBsynt model might be considered as a simple and useful tool for evaluating synthesis methods, allowing comparison of various reactions based on empirical data
Multi-stage evolution of the lithospheric mantle beneath the Hessian Depression (Germany) : peridotite xenoliths from Stöpfling
Get PDFPolicy as normative influence? : on the relationship between parental leave policy and social norms in gender division of childcare across 48 countries
No full textIn the present work, we addressed the relationship between parental leave policies and social norms. Using a pre‐registered, cross‐national approach, we examined the relationship between parental leave policies and the perception of social norms for the gender division of childcare. In this study, 19,259 students (11,924 women) from 48 countries indicated the degree to which they believe childcare is (descriptive norm) and should be (prescriptive norm) equally divided among mothers and fathers. Policies were primarily operationalized as the existence of parental leave options in the respective country. The descriptive and prescriptive norms of equal division of childcare were stronger when parental leave was available in a country – also when controlling for potential confounding variables. Moreover, analyses of time since policy change suggested that policy change may initially affect prescriptive norms and then descriptive norms at a later point. However, due to the cross‐sectional nature of the data, drawing causal inferences is difficult
