Customizing the Appearance of Sparks with Binary Metal Alloys.

Long-flying sparks are an essential part of several pyrotechnic effects. Unfortunately, and in contrast to colored flames, the color space of sparks is basically limited to the black body curve. With low-boiling-point metals, vapor-phase combustion and bright colorful flashes are achievable.

Intramolecular Phosphine-Promoted Knoevenagel Based Redox-Reaction.

A Knoevenagel based redox-reaction promoted by intramolecular phosphine sources is presented for the first time. The influence of different diketones, aldehydes, bases and acids was investigated. The effects of different substituents were evaluated based on their electronical influence on the diketone structure.

Square-Wave Electrogravimetry Combined with Voltammetry Reveals Reversible Submonolayer Adsorption of Redox-Active Ions.

Square-wave voltammetry on electrolytes containing reversible redox pairs in solution was complemented by acoustic microgravimetry, where multifrequency lock-in amplification provides for a time resolution of 2.5 ms and a frequency resolution after accumulation of 12 mHz. The instrument operates similar to a quartz crystal microbalance with dissipation monitoring (QCM-D).

Reversible functionalization and exfoliation of graphite by a Diels-Alder reaction with furfuryl amine.

Furfuryl amine-functionalized few-layered graphene was prepared a mechanochemical process by a [4 + 2] cycloaddition under solvent-free conditions. By employing ball milling, active sites are merged mostly at the edge of the graphene sheets which makes them prone to Diels-Alder click reactions (D-A) in the presence of a diene precursor. Consequently, one-pot grafting with furfuryl amine onto the graphene sheets, exfoliates pristine graphite resulting in functionalized few-layered graphene which is soluble in organic solvents.

Thiocyanatoarylation of Methyl Vinyl Ketone under Meerwein Conditions for the Synthesis of 2-Aminothiazole-Based Heterocyclic Systems.

4-Aryl-3-thiocyanatobutan-2-ones were prepared by Meerwein reactions from methyl vinyl ketone and aryldiazonium salts under copper(II) catalysis in 35-75% yields. α-Thiocyanato ketones regioselectively react with 1-methyl-3-aminopyrazole forming -(3-pyrazolyl)-substituted 2-aminothiazoles in 80-91% yields. An ester group in position 3 of the pyrazole induced a regioselective ring-closure reaction followed by an intramolecular cyclization, which gave first representatives of a new heterocyclic system, pyrazolo[4,3-]thiazolo[3,2-]pyrimidine, in 74-93% yields.

Selective Laser Melting of CuSn10: Simulation of Mechanical Properties, Microstructure, and Residual Stresses.

In this study, the evolution of mechanical properties, microstructure, and residual stresses during selective laser melting of CuSn10 components was studied. To provide a proper material model for the simulations, various CuSn10 parts were manufactured using selective laser melting and examined. The manufactured parts were also used to validate the developed model.

Influence of Foam Morphology on Flow and Heat Transport in a Random Packed Bed with Metallic Foam Pellets-An Investigation Using CFD.

Open-cell metallic foams used as catalyst supports exhibit excellent transport properties. In this work, a unique application of metallic foam, as pelletized catalyst in a packed bed reactor, is examined. By using a wall-segment Computational Fluid Dynamics (CFD) setup, parametric analyses are carried out to investigate the influence of foam morphologies (cell size ϕ=0.

Machine Learning Approach for Predictive Maintenance of the Electrical Submersible Pumps (ESPs).

Electrical submersible pumps (ESPs) are considered the second-most widely used artificial lift method in the petroleum industry. As with any pumping artificial lift method, ESPs exhibit failures. The maintenance of ESPs expends a lot of resources, and manpower and is usually triggered and accompanied by the reactive process monitoring of multivariate sensor data.

Chemistry of polyhalogenated nitrobutadienes, 17: Efficient synthesis of persubstituted chloroquinolinyl-1-pyrazoles and evaluation of their antimalarial, anti-SARS-CoV-2, antibacterial, and cytotoxic activities.

A series of 26 novel 1-(7-chloroquinolin-4-yl)-4-nitro-1-pyrazoles bearing a dichloromethyl and an amino or thio moiety at C3 and C5 has been prepared in yields up to 72% from the reaction of 1,1-bisazolyl-, 1-azolyl-1-amino-, and 1-thioperchloro-2-nitrobuta-1,3-dienes with 7-chloro-4-hydrazinylquinoline. A new way for the formation of a pyrazole cycle from 3-methyl-2-(2,3,3-trichloro-1-nitroallylidene)oxazolidine () is also described. In addition, the antimalarial activity of the synthesized compounds has been evaluated in vitro against the protozoan malaria parasite .

Zn detection of a benzimidazole 8-aminoquinoline fluorescent sensor by inhibited tautomerization.

A new fluorescent chemosensor based on 8-aminoquinoline L1 bearing a benzimidazole moiety was synthesized, which exists as two predominant tautomers L1A and L1B in diluted DMSO-d solution. Among various metal ions, L1 showed a highly selective and sensitive turn-on fluorescence response to the presence of Zn ions in methanol. The detection limit for Zn by L1 was calculated to be 1.

Model-Based Product Temperature and Endpoint Determination in Primary Drying of Lyophilization Processes.

Lyophilization process design still relies mainly on empirical studies with high experimental loads. In the regulatory demanded Quality by Design approach, process modeling is a key aspect. It allows process design, optimization and process control to ensure a safe process and product quality.

-Block metal complexes with bis(pyrazol-1-yl)acetato ligands.

The hetereoscorpionate ligands bis(pyrazol-1-yl)acetic acid (Hbpza) and bis(3,5-dimethylpyrazol-1-yl)acetic acid (Hbdmpza) are reacted with [Sn(OAc)] or [Sn(acac)] to yield the corresponding Sn(II) complexes. A single crystal X-ray determination for the in solution monomeric complex [Sn(bpza)] (1a) revealed a dinuclear molecular structure [Sn(bpza)] (1b), with κ-N,N,O-coordinated bpza ligands at each of the Sn(II) and two bpza ligands μ-bridging between the Sn(II) centres. The molecular structure of [Sn(bdmpza)] (2) exhibits a homoleptic bisligand complex with both ligands displaced by the free electron pair, which is proven by DFT calculations.

Recovery Observations from Alkali, Nanoparticles and Polymer Flooding as Combined Processes.

We have studied wettability alterations through imbibition/flooding and their synergy with interfacial tension (IFT) for alkalis, nanoparticles and polymers. Thus, the total acid number (TAN) of oil may determine the wetting-state of the reservoir and influence recovery and IFT. Data obtained demonstrate how the oil TAN number (low and high), chemical agent and reservoir mineralogy influence fluid-fluid and rock-fluid interactions.

Biting the bullet: When self-efficacy mediates the stressful effects of COVID-19 beliefs.

The impact that COVID-19 had on individuals globally has been immense. Our study aims to determine if the various COVID-19 related beliefs (information seeking; invulnerability; disruption; health importance and response effectiveness) are predictors of perceived stress and if self-efficacy acts as a mediator in reducing perceived COVID-19 related stress. From a large sample of 23,629, data were assessed using validated multi-item measures for seven COVID-19 related beliefs, self-efficacy and perceived stress.

Dipolar Interactions and Protein Hydration in Highly Concentrated Antibody Formulations.

Molecular interaction mechanisms in high-concentrated protein systems are of fundamental importance for the rational development of biopharmaceuticals such as monoclonal antibody (mAb) formulations. In such high-concentrated protein systems, the intermolecular distances between mAb molecules are reduced to the size of the protein diameter (approx. 10 nm).

Expert-enhanced machine learning for cardiac arrhythmia classification.

We propose a new method for the classification task of distinguishing atrial fibrillation (AFib) from regular atrial tachycardias including atrial flutter (AFlu) based on a surface electrocardiogram (ECG). Recently, many approaches for an automatic classification of cardiac arrhythmia were proposed and to our knowledge none of them can distinguish between these two. We discuss reasons why deep learning may not yield satisfactory results for this task.

Surface Tuning of Wood via Covalent Modification of Its Lignocellulosic Biopolymers with Substituted Benzoates-A Study on Reactivity, Efficiency, and Durability.

Chemical modification of wood applying benzotriazolyl-activated carboxylic acids has proven to be a versatile method for the durable functionalization of its lignocellulosic biopolymers. Through this process, the material properties of wood can be influenced and specifically optimized. To check the scope and limitations of this modification method, various benzamide derivatives with electron-withdrawing (EWG) or electron-donating (EDG) functional groups in different positions of the aromatic ring were synthesized and applied for covalent modification of Scots pine ( L.

Buchwald-Hartwig Amination of Aryl Halides with Heterocyclic Amines in the Synthesis of Highly Fluorescent Benzodifuran-Based Star-Shaped Organic Semiconductors.

The study of palladium-catalyzed amination of bromobenzene with aromatic and heterocyclic amines, widely used in the synthesis of organic semiconductors, was performed. The best conditions for the coupling of aryl bromides with carbazole, diphenylamine, phenoxazine, phenothiazine, 9,9-dimethyl-9,10-dihydroacridine, and their derivatives have been developed. Based on the results, nine new star-shaped organic semiconductors, exhibiting up to 100% fluorescent quantum yield in the 400-550 nm range, have been synthesized in good yields.

Implementing the Circular Economy by Tracing the Sustainable Impact.

Sustainability is one of the most critical issues today. Thus, the unsustainable consumption of resources, such as raw materials, CO emissions, and the needs to be changed. One framework for a more sustainable economy is the .

Determination of the through-plane profile of vanadium species in hydrated Nafion studied with micro X-ray absorption near-edge structure spectroscopy - proof of concept.

Vanadium-ion transport through the polymer membrane results in a significant decrease in the capacity of vanadium redox flow batteries. It is assumed that five vanadium species are involved in this process. Micro X-ray absorption near-edge structure spectroscopy (micro-XANES) is a potent method to study chemical reactions during vanadium transport inside the membrane.

Quantifying the Impact of Parametric Uncertainty on Automatic Mechanism Generation for CO Hydrogenation on Ni(111).

Automatic mechanism generation is used to determine mechanisms for the CO hydrogenation on Ni(111) in a two-stage process while considering the correlated uncertainty in DFT-based energetic parameters systematically. In a coarse stage, all the possible chemistry is explored with gas-phase products down to the ppb level, while a refined stage discovers the core methanation submechanism. Five thousand unique mechanisms were generated, which contain minor perturbations in all parameters.

Corrigendum: Trust Dynamics and Verbal Assurances in Human Robot Physical Collaboration.

[This corrects the article DOI: 10.3389/frai.2021.

Improvement of the froth flotation of LiAlO and melilite solid solution via pre-functionalization.

In this work froth flotation studies with LiAlO (lithium-containing phase) and Melilite solid solution (gangue phase) are presented. The system was optimized with standard collectors and with compounds so far not applied as collectors. Furthermore, the principle of self-assembled monolayers was introduced to a froth flotation process for the first time resulting in excellent yields and selectivities.

Phosphine-Catalyzed Aryne Oligomerization: Direct Access to α,ω-Bisfunctionalized Oligo(-arylenes).

A phosphine-catalyzed oligomerization of arynes using selenocyanates was developed. The use of JohnPhos as a bulky phosphine is the key to accessing α,ω-bisfunctionalized oligo(-arylenes) with RSe as the substituent at one terminus and CN as the substituent at the other. The formation of RPSeR' cations, serving as sterically encumbered electrophiles, hinders the immediate reaction that affords the 1,2-bisfunctionalization product and instead opens a competitive pathway leading to oligomerization.

Interaction of Reactive Gases with Platinum Aerosol Particles at Room Temperature: Effects on Morphology and Surface Properties.

Nanoparticles produced in technical aerosol processes exhibit often dendritic structures, composed of primary particles. Surprisingly, a small but consistent discrepancy was observed between the results of common aggregation models and in situ measurements of structural parameters, such as fractal dimension or mass-mobility exponent. A phenomenon which has received little attention so far is the interaction of agglomerates with admixed gases, which might be responsible for this discrepancy.