Successive Reduction Research Articles

The Concept of Optimal Dynamic Pedalling Rate and Its Application to Power Output and Fatigue in Track Cycling Sprinters-A Case Study.

Sprint races in track cycling are characterised by maximal power requirements and high-power output over 15 to 75 s. As competition rules limit the athlete to a single gear, the choice of gear ratio has considerable impact on performance. Traditionally, a gear favouring short start times and rapid acceleration, i.e., lower transmission ratios, was chosen. In recent years, track cyclists tended to choose higher gear ratios instead. Based on a review of the relevant literature, we aimed to provide an explanation for that increase in the gear ratio chosen and apply this to a 1000 m time trial. Race data with continuous measurements of crank force and velocity of an elite track cyclist were analysed retrospectively regarding the influence of the selected gear on power, cadence and resulting speed. For this purpose, time-dependent maximal force-velocity (F/v) profiles were used to describe changes in performance with increasing fatigue. By applying these profiles to a physical model of track cycling, theoretical power output, cadence and resulting speed were calculated for different scenarios. Based on previous research results, we assume a systematic and predictable decline in optimal cadence with increasing fatigue. The choice of higher gear ratios seems to be explained physiologically by the successive reduction in optimal cadence as fatigue sets in. Our approach indicates that average power output can be significantly increased by selecting a gear ratio that minimises the difference between the realised cadence and the time-dependent dynamic optimum. In view of the additional effects of the gear selection on acceleration and speed, gear selection should optimally meet the various requirements of the respective sprint event.

СПРОБА ІСТОРИКО-ПСИХОЛОГІЧНОЇ РЕКОНСТРУКЦІЇ ОСОБЛИВОСТЕЙ ЕТНОНАЦІОНАЛЬНОГО САМОУСВІДОМЛЕННЯ УКРАЇНСЬКОЇ МОЛОДІ В ДРУГІЙ ПОЛОВИНІ XIX – НА ПОЧАТКУ XX СТ.

Based on the method of historical and psychological reconstruction, an attempt was made to reveal the social and psychological features of Ukrainian youth's ethno-national self-awareness in the second half of the 19th and early 20th centuries. According to the reviewed artistic and journalistic literature of that period, 195 fragments were selected which had reflected various aspects of the ethno-national consciousness of the Ukrainians at that time. The psychological and historical content of these fragments was assessed by experts – 35 psychology scientists and 116 history teachers. As a result of successive reduction of the number of fragments to 15 and factor analysis, five aspects were determined that reflected the researched process: enlightenment, activity, traditions, unity and involvement. The obtained indicators were projected on the current state of Ukrainian youth's ethno-national self-consciousness. The online survey covered 2,202 students from 35 universities in different regions of Ukraine. Students evaluated the fragments from the point of view of their reflection of Ukrainian youth's ethno-national self-awareness in the second half of the 19th and early 20th centuries, the importance of their content for the respondents themselves and for modern Ukrainian youth in general. The applied procedure provided grounds for determining the following social and psychological features of Ukrainian youth's ethno-national self-awareness in the second half of the 19th and early 20th centuries: understanding the importance of enlightenment, joint organizational activity, psychosocial empowerment with traditions, unity with the people around, involvement in the space of collective existence.

Features of obtaining metallurgical products in the solid-state hydride synthesis conditions

A scientific substantiation of solid-phase feedstock choice and preparation has been carried out, and the thermodynamic and kinetic aspects of solid-state hydride synthesis (SHS) of metal products have been analyzed using the nickel dichloride reduction as an example. The preliminary dehydration modes and methods for controlling the complete removal of crystalline water from chloride raw materials and Olenegorsk superconcentrate, which is natural oxide raw material, are described. Conditions, including initial solid chloride particle sizes, are established under which diffusion complications of reduction to metal in methyldichlorosilane vapor are minimized. Thermodynamic estimates of nickel chlorides and oxides reduction possibility, iron and copper with ammonia and methane at temperatures of 400-1000 K in equilibrium conditions have been carried out. It has been shown that the stoichiometric coefficients of the nickel dichloride in ammonia overall reduction reaction calculated by thermodynamic modeling are in agreement with experimental data. In contrast to the copper dichloride reduction, for nickel dichloride the formation of metal monochloride at the intermediate stage is uncharacteristic, which is associated with a higher thermal stability of nickel dichloride. The main kinetic regularities of the reduction of nickel, copper, and iron to metal under SHS conditions in ammonia, monosilane, and methane, as well as the nickel dichloride with methyldichlorosilane vapor and methane successive reduction, are considered. Approximation of experimental data by topochemical equations in a linear form showed that for reduction degrees a up to 0.7-0.8, these data are satisfactorily described by the Roginsky – Schultz equation. For a > 0,8 the “shrinking sphere” model works better, which confirms the localization of the solid-state reduction reaction at the interface, moves deep into the crystal with the formation of a of interlocked metal germs. The importance and prospects of the results obtained for the theory development of metallurgical processes, deep complex processing of natural iron oxide raw materials, metal products and new generation materials production, including superhydrophobic ones, are discussed. The relevance of the study from the point of view of applying the method of physical and chemical analysis to the study of complex heterogeneous metallurgical processes is noted.

The Shockley–Queisser limit and the conversion efficiency of silicon-based solar cells

According to some estimates, every hour, Sun provides planet Earth with more energy than humankind consumes in a whole year. Part of this energy has been essential to ensure living conditions (warmth and food production, for instance) and, more recently, to generate electricity by means of atmospheric (aeolian) and/or geographical (hydropower) sources. In addition to these, the direct (photovoltaic PV) conversion of solar radiation into electricity represents a very elegant method of power generation that causes minimum (or no) environmental disturbance. As a result, numerous efforts have been dedicated to further advance the achievement of clean and sustainable electricity, as supplied by the PV science and technology. Within this scenario, the association of PV with the silicon (Si) semiconductor industry played a crucial role–either by introducing new scientific insights or by promoting successive costs reductions in the field of renewable energy conversion. Yet, the performance of these so-called (either crystalline or amorphous) Si-based solar cells was always a matter of concern. In fact, the subject gained attention with the seminal work by Walter Shockley and Hans Queisser that, in 1961, proposed a model according to which the maximum efficiency of a solar cell is determined by both the solar spectrum and the properties of the semiconductor material. Since then, the work by Shockley and Queisser (also known as the Shockley–Queisser limit) has experienced some improvements and became a reference in the field. Motivated by these facts, along with the main scientific–technological achievements they provided, the Shockley–Queisser limit and the conversion efficiency of the Si-based solar cells along the last 60 years form the basis of this paper.

A Modified Technique for Induced Gingival Growth Around Compromised Teeth Prior to Implant Placement: A Report of Two Cases

Regenerative and reconstructive periodontal plastic surgery are important options for treating marginal tissue recession and can be indicated for root coverage or periodontal procedures prior to implant placement. Among the available procedures, periodontal flaps with subepithelial connective tissue graft (CTG) is the most common treatment option to achieve proper tissue manipulation. The present study proposes a modification of a previous technique for inducing spontaneous gingival growth around teeth that will be extracted prior to implant placement, through successive reduction of the buccal root surface. This successive reduction of root surfaces is performed with diamond burs, and such reductions create space for the gingival tissue to grow coronally by reducing root convexity and, consequently, stimulating the healing process with the formation of granulation tissue that will then differentiate into keratinized tissue. The presented technique is suggested to improve the esthetic outcomes for cases involving tooth extraction, implant placement in the extraction socket, and immediate loading with interim restoration and CTG.

Phylogeny of the amphibamiform temnospondyls: the relationship of taxa known by adults, larvae and neotenes

The Amphibamiformes, small temnospondyls from late Palaeozoic rocks, have been increasingly considered as the stem-group of some or all extant amphibians (Lissamphibia). Their relationships have become intensely studied after the discovery of new taxa and the revision of poorly known ones, but understanding is hampered by the fact that amphibamiforms fall into two very distinct groups: (a) terrestrial taxa known by adults only (Amphibamidae, Micropholidae) and (b) aquatic taxa known by larvae and neotenic adults (Branchiosauridae). The Branchiosauridae were recognized as a clade supported by a suite of larval synapomorphies, but the unknown larval morphology of the terrestrial clades leaves the question open to whether some branchiosaurid apomorphies might have been more widely distributed. Recently, some branchiosaurid specimens from Nýřany (Czech Republic) were proposed to be larvae of olsoniforms and amphibamids, and together with a revision of ancient branchiosaurid-like taxa from the United States and France prompt a re-analysis of this issue. In a phylogenetic analysis of 48 taxa and 113 characters, the Branchiosauridae were found to be monophyletic and nest in an unresolved trichotomy with Amphibamidae and the putative relatives of Lissamphibia. The present analysis finds the hypothesized olsoniform larvae from Nýřany to be adults of Branchiosaurus salamandroides, whereas some of the larvae from Mazon Creek (Illinois, USA) are not branchiosaurids, but immature specimens of the amphibamid Amphibamus grandiceps. Within branchiosaurids, four clades have been identified: (a) the Carboniferous Anthracobamus clade (Anthracobamus, Montceaubatrachus), (b) the mostly Carboniferous Branchiosaurinae (Branchiosaurus, Milnererpeton) and two largely Permian clades, the newly defined Apateoninae (genus Apateon) and Leptorophinae (Melanerpeton, Leptorophus, Schoenfelderpeton) clade. Branchiosaurid evolution involved a trend towards an enhanced paedomorphosis, a modification of branchial teeth, and successive reduction of bone in the scales and pectoral girdle.

Gold Raspberry Shell Grown onto Nonspherical Lithium Niobate Nanoparticles for Second Harmonic Generation and Photothermal Applications

AbstractNanoparticles (NPs) containing a lithium niobate (LiNbO3) core and a gold shell are prepared using a combination of seeded‐growth and layer‐by‐layer approaches. The method includes first the surface charge reversal of lithium niobate with branched polyethyleimine, second, the electrostatic binding of gold seeds, and third, successive reduction steps of gold chloride onto the gold‐seeded LiNbO3 NPs for the progressive and surface‐directed growth of the gold shell. The influence of three synthesis parameters, namely, pH, initial density of gold seeds covering the lithium niobate core, and gold chloride concentration, on the NPs’ characteristics (structural properties, plasmon band, surface charge, hydrodynamic diameter) is studied. The progress of the gold shell growth is investigated by X‐ray photoelectron spectroscopy and time‐of‐flight secondary ion mass spectrometry. In addition, it is shown that LN@Au core–shell NPs can emit a second harmonic generation signal when excited by a femtosecond laser. Finally, photothermal properties are studied, showing an increase of temperature of 8.6 °C upon infrared excitation, with an estimated light‐to‐heat conversion efficiency of 40% and a specific absorption rate of 8000 W g−1.

Active Control System Applied to Vibration Level Control in High-Speed Elevators

This work presents an active control system applied to vibration level reduction in high-performance vertical transport, aiming at improving the passengers’ comfort in high-speed elevators. The control system design includes the use of a Proportional Integral Derivative (PID) control. Three strategies were proposed in order to achieve a 90% reduction in the vibration amplitudes: (I) the consecutive reduction of 90% of the displacements, (II) the consecutive reduction of 90% of the velocity, and (III) the consecutive reduction of 90% of the acceleration. The presentation of these three proposals allows their application for the use of different sensors. The performance of each strategy was evaluated through mathematical modeling and numerical simulations of a vertical transport with 4 degrees of freedom, submitted to excitations arising from rail deformations. Vibration and comfort levels in the cabin were numerically analyzed, taking into account ISO 2631 and BS 6841 standards for elevator lateral acceleration level and comfort level felt by passengers. Numerical simulations showed that the force required to reduce the vibration levels is practically the same for the three proposed strategies. However, strategy (III) – the successive reduction of 90% of acceleration – proved to be more efficient at improving passengers’ comfort level when compared to the other two strategies.

Diagenetic processes and nutrients diffusive fluxes at the sediment-water interface in the Bizerte Lagoon (North Tunisia)

Diagenetic reactions occurring in the sediments of Bizerte Lagoon along with their seasonal variation were assessed through examining the concentration profiles of nutrients and dissolved Fe and Mn in the supernatant water and pore waters, as well as the profiles of total organic carbon, carbonates, Fe and Mn contents in the particulate phase. The results indicate that these diagenetic reactions followed the classical sequence of oxidant reduction following the degradation of organic matter with a successive reduction of NO3−, MnO2, Fe (OH)3 and SO42−. In particular, a delay was observed in the winter sequence which occurred at greater depth due to higher Eh in surface layer. Generally, NO3−, NH4+ and PO43− seem to originate from sediments as reflected by their measured flux from sediments to the water column while the reverse was quoted for SO42− as reported from other Mediterranean environments. In addition, oxygenation of the water column reduces the diffusive fluxes of (NO3−, NH4+, PO43−) released into the pore water during mineralization of organic matter.

Periodically kicked feedforward chains of simple excitable FitzHugh–Nagumo neurons

This article communicates results on regular depolarization cascades in periodically kicked feedforward chains of excitable two-dimensional FitzHugh–Nagumo systems driven by sufficiently strong excitatory forcing at the front node. The study documents a parameter exploration by way of changes to the forcing period, upon which the dynamics undergoes a transition from simple depolarization to more complex behavior, including the emergence of mixed-mode oscillations. Both rigorous studies and careful numerical observations are presented. In particular, we provide rigorous proofs for existence and stability of periodic traveling waves of depolarization, as well as the existence and propagation of a simple mixed-mode oscillation that features depolarization and refraction in alternating fashion. Detailed numerical investigation reveals a mechanism for the emergence of complex mixed-mode oscillations featuring a potentially high number of large amplitude voltage spikes interspersed by an occasional small amplitude reset that fails to cross threshold. Further careful numerical investigation provides insights into the propagation of this complex phenomenology in the downstream, where we see an effective filtration property of the network; the latter amounts to a successive reduction in the complexity of mixed-mode oscillations down the chain.

A near-infrared absorbing ring-fused quinoid-bisboron pyrrole dye with double BF2 chelation

Ring-fused quinoid-bisboron pyrrole dyes with double BF2 chelation (QBBP) were prepared for the first time. According to X-ray crystallographic analysis, the centrosymmetric structure of QBBP was confirmed. The core of the central quinone moiety and two ring-fused pyrroles is almost planar, and the arrangement of aggregates involve J-type packing. Bisboron dye QBBP underwent two successive one-electron reduction and two successive one-electron oxidation processes. QBBP absorbs in the near-infrared (NIR) with a high molar extinction coefficient. Although QBBP shows no fluorescence and low intersystem crossing (ISC) efficiency, it has considerable photothermal conversion efficiency and is desirable for a photothermal-photodynamic therapy agent.

Redox-manipulated RhOx nanoclusters uniformly anchored on Sr2Fe1.45Rh0.05Mo0.5O6–δ perovskite for CO2 electrolysis

The sluggish reaction kinetics of CO2 electroreduction in perovskite-based cathodes severely limits the efficiency of solid oxide electrolysis cells (SOECs). The construction of the high-density active sites on the perovskite surface is crucial for promoting CO2 electrolysis in SOEC. In this study, we explore a redox-induced redispersion strategy to produce RhOx nanoclusters uniformly anchored on a Sr2Fe1.45Rh0.05Mo0.5O6–δ (SFRhM) perovskite surface with a high density of 36,000 µm−2. Compared with non-uniformly distributed RhOx nanoparticles on Sr2Fe1.5Mo0.5O6–δ (RhOx/SFM) prepared by a conventional impregnation process, the successive reduction and oxidation treatment first exsolves the highly dispersed RhFe alloy nanoparticles on SFRhM and then selectively dissolves the iron species in the RhFe alloy nanoparticles into the bulk of SFRhM, resulting in fully exposed RhOx nanoclusters uniformly anchored on the SFRhM surface (RhOx@SFRhM). Electrochemical measurements and density functional theory calculations indicate that the high-density RhOx@SFRhM interfaces promote CO2 adsorption and activation during CO2 electrolysis, thus leading to improved electrocatalytic activity and stability compared to that of its SFRhM and RhOx/SFM counterparts.

Salt reduction in potato chips using microparticulated salt and spices: A sensory study with consumers

AbstractThis study aimed at reducing the amount of salt added to potato chips by decreasing the size of salt particles. First, a selected panel (n = 15 assessors) evaluated the saltiness of potato chips added with refined and microparticulated salt using the magnitude estimation. The amount of 1.6% of refined salt, previously determined as just‐about‐right in potato chips, was equivalent to 1.2% of microparticulated salt. Afterward, an acceptance test (n = 115 consumers) was performed with six samples of potato chips added with microparticulated salt, with successive reductions from 1.2% to 0%, combined with a seasoning made of powdered parsley and onion. Results showed that it is possible to reduce salt by up to 65% without a significant decrease (p > .05) in acceptance. In conclusion, microparticulated salt associated with the flavor‐enhancing power of traditional seasonings proved to be a valuable strategy to reduce sodium in snacks.Practical ApplicationsPrevious studies have proposed strategies to reduce salt added topically to snacks without combining sodium chloride (NaCl) with additives such as potassium chloride (KCl) and monosodium glutamate (MSG). This study demonstrated, using a trained panel on magnitude scale, that decreasing the size of salt particles by a simple sieving process made it possible to reduce 25% of the salt added to potato chips. Further reduction was possible by combining microparticulated salt with powdered onion and parsley without a significant (p > .05) drop in consumer's acceptance (N = 115). The strategy not only makes snacks healthier but also improves flavor and keeps the product's clean label, which is a demand of the consumer.

Abstract 5424: Selection of RP3D of xevinapant in combination with CRT in patients with LA SCCHN

Abstract Xevinapant, an antagonist of Inhibitor of Apoptosis Proteins (IAPs) showed significant improvement in locoregional control at 18 months (LRC18; primary endpoint), overall survival (OS) and progression-free survival (PFS) at an oral dose of 200 mg/day given on days 1-14 every 3 weeks in combination with CRT versus CRT with placebo in a phase II trial in patients with high-risk LA SCCHN (NCT02022098). In the dose escalation (DE) part of NCT02022098, 200 mg/day was the maximum tolerated dose and a trend of dose-response for efficacy in the 100-300 mg/day dose range was observed. The phase III TrilynX study of xevinapant plus CRT in patients with LA SCCHN is currently enrolling (NCT04459715). Here we present the integrated rationale for the recommended phase III dose (RP3D) of xevinapant 200 mg/day based on all available clinical and preclinical data and modeling and simulation (M&S). At the RP3D, ~95% of the patients are projected to have free trough concentrations above in vitro IC50 for cIAP1 degradation (a pharmacodynamic [PD] marker), based on a population (pop) PK M&S. In patients, average free concentration over the dosing interval at RP3D is similar to that associated with maximal efficacy in preclinical SCCHN models. Pop PK/PD M&S suggests that maximal cIAP1 degradation is maintained in PBMCs with 100-200 mg/day doses during the 14-day dosing period, with a trend of dose-response for the partial cIAP1 degradation at the end of the 3-week cycle. Exposure response (E-R) analyses were conducted based on the pooled datasets of DE and randomized parts of study NCT02022098 (n=62 treated with xevinapant). Logistic regressions showed that probabilities of LRC18, overall response, complete response, and the composite safety endpoint of “mucositis and/or dysphagia” increase with increasing exposure (p<0.05). Statistically significant E-R relationships were not discernible for any other evaluated safety endpoints or for PFS, OS, or duration of LRC. However, patients in higher exposure subgroups showed a longer duration of LRC. In summary, integration of preclinical pharmacology, clinical efficacy and safety profiles, clinical PK/PD, popPK, and E-R analyses support the RP3D selection of xevinapant at 200 mg/day administered on days 1-14 every 3 weeks with concomitant CRT, allowing for successive dose reductions to 150 mg and 100 mg for management of toxicities. Citation Format: Yulia Vugmeyster, Abhigyan Ravula, Elisabeth Rouits, Paul M. Diderichsen, Huub J. Kleijn, Kosalaram Goteti, Andreas Schroeder, Karthik Venkatakrishnan. Selection of RP3D of xevinapant in combination with CRT in patients with LA SCCHN [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5424.

A Distinctive Pattern for Substituent Effects on Transition Metal Centers: Enhanced Electron-Donating Capacity of Cationic Palladium Species

A Distinctive Pattern for Substituent Effects on Transition Metal Centers: Enhanced Electron-Donating Capacity of Cationic Palladium Species

Nanostructured regulation of the surface properties and hydrophobicity of nickel and iron by solid-state reduction and modifying methods

metal samples obtained by solid-state hydride synthesis (SHS) of metals and layering of different-sized molecules (LDM) of ammonium and organosilicon compounds has been carried out. It was found that the dispersed metal products of SHS are significantly more hydrophobic (on average, by an order of magnitude) compared to metals modified in vapors of industrial water repellents. It has been established that among the metal products of SHS based on nickel, copper, and iron with a carbosiloxane nanofilm on the surface, the samples based on iron are the most hydrophobic and heat-resistant in air. The most hydrophilic and chemically active samples were nickel-based, which had a fairly developed surface (about 50 m2/g). The revealed patterns of regulation of the surface properties and hydrophobicity of metal synthesis products are associated with the strongest interatomic metal-silicon chemical interaction in the surface layer of iron-based samples, confirmed by XPS spectroscopy. When a metal product is obtained by successive reduction of the initial solid- phase raw material (ore) in methyldichlorosilane (MDCS) vapor and in a methane stream, MDCS performs the functions of a reducing agent and modifier of the metal surface. The metal at the time of appearance, being in a reducing medium, has a reactive surface and actively interacts with MDCS molecules containing chemically stable Si-C groups, with the formation of a strong chemisorption bond between the metal and the protective carbosiloxane film formed during synthesis, no more than 4–5 nm. Such a mechanism of the process under SHS conditions makes it possible to carry out the reduction and useful modification of the metal within the framework of a single technological process and in one reactor.This research paper was recommended for publication by the organizing committee of the International Conference on Nanophysics and Nanomaterials, 24-25 November 2021, Saint Petersburg, Mining University.

Improving the efficiency of emergency control systems for future-oriented connection of sources of distributed generation

Improvement of energy-intensive technological processes of industrial enterprises requires increasing the reliability and efficiency of power supply of consumers. In this regard, one of the priority areas associated with introduction of the sources of distributed generation is mainstreamed in energy industry. This trend has both beneficial and negative impacts. It makes difficult to control normal, emergency, and post-emergency modes of power supply systems of enterprises of ferrous metallurgy. When new sources of distributed generation are introduced under the conditions of complex closed-loop power supply system, it is necessary to assess the level of short-circuit currents to check the electrical equipment and residual voltages across the busbars of the consumers of ferrous metallurgy. Also, it is necessary to determine the critical time of generators dropping and evaluate the stability in case of isolated operation. An algorithm has been developed for automated search of a dividing point in case of an emergency and isolated operation depending on the power balance to maintain stability. It is based on a combination of the method of successive network reduction and step-by-step method. To improve the reliability of essential consumers, the authors have developed an algorithm for automatic search for the dividing point during operation of emergency control system depending on the power balance to maintain stability. The authors have developed proprietary software to assess the effectiveness of emergency automation equipment of multi-level complex closed-loop power supply system of metallurgical enterprise. Performed calculations and analysis of emergency and post-emergency modes are designed to develop a comprehensive approach of a set of measures to ensure the reliability and stability of essential consumers in the mode of automatic search.

(Electro)chemical and antimicrobial characterization of novel Ru(II) bipyridine complexes with acetylpyridine analogs

Three ruthenium-bipyridine complexes (1–3) carrying acetylpyridine ligand unit were synthesized in methanol via the reaction of [RuCl2(bpy)2] with corresponding acetylpyridine (2-, 3-, and 4-acpy). Obtained complexes were characterized by (1H and 13C) NMR and IR spectroscopy, MS spectrometry, UV‒vis spectrophotometry, and cyclic voltammetry. Their structural characterization revealed bidentate coordination mode for 2-acpy while 3- and 4-acpy acted as monodentate ligands. The electrochemical profile of newly synthesized compounds was investigated by cyclic voltammetry which confirmed their electrochemical activity. Voltammetric responses within the −1.20 < Ep < 1.50 V range of potentials were summarized in two major events: Ru(II)→Ru(III) oxidation spotted at app. ΔEp = 0.65 V and successive reductions of bpy units located from ‒0.79 V to 0.47 V (vs. Ag/AgCl (3 M) electrode). The DNA-binding activity of the complexes was evaluated by both UV‒vis spectrophotometry and cyclic voltammetry indicating DNA-intercalation with a slight contribution of electrostatic interactions. Furthermore, antimicrobial activity was tested against bacterial and fungal strains, for which moderate activity was observed. Assessment of in vitro toxicity against freshly hatched nauplii of Artemia salina as well as radical scavenging capacity was evaluated. The test compounds showed neither toxicity nor antioxidant activity.

Electrochemical conversion of CO2 to C2 oxygenates on Pb(II)-salen catalysts-coated graphite electrodes: Role of salen ligand and appended ligand-substituents to the production

• Three Pb(II)-salen complexes synthesized by metalation reaction in presence of Et 3 N. • Pb-salen complexes showed better CO 2 conversion efficiency than pure PbO. • –NH 2 in Pb(II)-salen ligand increased availability of CO 2 /CO for multiple products. • FE of 57% and 36% achieved for ethanol and acetic acid for Complex 2 and Complex 3. Electrochemical reduction of CO 2 (ERC) generates higher-value and higher-energy density multicarbon C 1+ products that serve as alternatives to fossil fuels and feedstocks for the chemical industries. Herein, we uncover three Pb(II)-salen complexes ( 1 = [Pb II (L H )] 0 , 2 = [Pb II (L NO 2 )] 0 , and 3 = [Pb II (L NH 2 )] 0 ) as the catalysts that were deposited onto graphite electrodes to fabricate working electrodes. In complex 1 , no functional groups were incorporated in the parent H 2 L H ligand backbone, while, a –NO 2 and an –NH 2 functional groups were present in the ligand frameworks in complex 2 and complex 3 , respectively. The ERC by complex 1 -coated graphite electrode generated only C 1 products, formic acid (HCOOH, FE = 7%; SE = 41%), and methanol (CH 3 OH, FE = 28%; SE = 59%) at −1.80 V vs . Ag/AgCl, at pH ∼ 7.0. However, ERC under the same condition employing complex 2 and complex 3 as electrocatalysts, C 2 products formation predominated. While, ethanol (CH 3 CH 2 OH) was formed as the major C 2 product with FE = 57%, SE = 66% and TON (TOF) = 31680 (8.8 s −1 ) in the presence of complex 2 , mainly acetic acid (CH 3 COOH, FE = 36%; SE = 54%) with overall product FE = 67% was realized using complex 3 as the electrocatalyst. Thus, the presence of functional groups facilitated C–C coupling between the pertinent intermediates. The role of the ligand frameworks was to modify the substrate and/or proton concentrations over the electrode surfaces for the successive reduction of CO 2 to oxygenates.

Low velocity impact resistance of thin and toughened carbon fibre reinforced epoxy

This study investigates the effect of core-shell rubber nanoparticle and block copolymer matrix modifications on the low velocity impact resistance of thin (∼1.6 mm), multi-axial carbon fibre reinforced epoxy laminates. The results demonstrate a strongly enhanced damage resistance predominantly to impact energies of 9 J and 13 J. Lower impact energies do not sufficiently activate the energy dissipating capabilities of the applied toughening agents. In the case of 9 J impacts, it is found that the damage resistance increases with increasing modifier concentration by a successive reduction of the indentation depth. Once the impact causes large-scale fibre fracture (13 J), the damage mode changes and an increasing matrix toughness leads to a strong reduction of the damage area. However, a proper bonding between matrix and the embedded fibres is a mandatory precondition to take advantage of a core-shell rubber and block copolymer toughened matrix.