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We investigate the convergence of chemical reaction networks (CRNs), aiming to establish an upper bound on their reaction rates. The nonlinear characteristics and discrete composition of CRNs pose significant challenges in this endeavor. To circumvent these complexities, we adopt an information geometric perspective, utilizing the natural gradient to formulate a nonlinear system. This system effectively determines an upper bound for the dynamics of CRNs. We corroborate our methodology through numerical simulations, which reveal that our constructed system converges more rapidly than CRNs within a particular class of reactions. This class is defined by the count of chemicals, the highest stoichiometric coefficients in the reactions, and the total number of reactions involved. Further, we juxtapose our approach with traditional methods, illustrating that the latter falls short in providing an upper bound for CRN reaction rates. Although our investigation centers on CRNs, the widespread presence of hypergraphs across various disciplines, ranging from natural sciences to engineering, indicates potential wider applications of our method, including in the realm of information science.

Thiol-click reactions are widely used in the preparation of thermosets. The network build-up process follows step-wise polymerization behavior, which is commonly analyzed assuming ideal step-wise behavior using well- known expressions such as the Flory-Stockmayer equation for the prediction of the gel point conversion. However, a number of factors contributing to departures from the expected ideal behavior can be identified: a) impurity of the reagents, b) complexity of the reaction mechanism and c) internal cyclization processes. In order to maximize the accuracy of predictions about the expected crosslinking behavior and therefore fine-tune the design of thermosets designed as dual-curing systems or covalent adaptable networks (CANs), it is necessary to take into consideration all these sources of non-ideality. In this work, we aim to describe the effects of such factors on the network build-up process of thiol-click thermosets, making use of the recursive methodology of Miller and Macosko. The contribution of each factor is analyzed separately and their overall combined effect is discussed in relation with real data reported in the literature and experimental results., This work was funded by the Spanish Ministry of Science and Inno- vation (MCIN/AEI/10.13039/501100011033) through R&D projects PID2020-115102RB-C21 and PID2020-115102RB-C22, and also by Generalitat de Catalunya (2021-SGR-154). X. Fernández-Francos and O. Konuray acknowledge the Serra-Húnter programme (Generalitat de Catalunya)., Postprint (published version)

While important for many industrial applications, chemical reactions responsible for the charging of solids in water are often poorly understood. We theoretically investigate the charging kinetics of solid-liquid interfaces and find that the time-dependent equilibration of surface charge contains key information not only on the reaction mechanism, but also on the valency of the reacting ions. We construct a nonlinear differential equation describing surface charging by combining chemical Langmuir kinetics and electrostatic Poisson-Boltzmann theory. Our results reveal a clear distinction between late-time (near-equilibrium) and short-time (far-from-equilibrium) relaxation rates, the ratio of which contains information on the charge valency and ad- or desorption mechanism of the charging process. Similarly, we find that single-ion reactions can be distinguished from two-ion reactions, as the latter show an inflection point during equilibration. Interestingly, such inflection points are characteristic of autocatalytic reactions, and we conclude that the Coulombic ion-surface interaction is an autocatalytic feedback mechanism.

The mobile phone industry, one of the fastest advancing sectors in production over the last few decades, has been associated with a high e-waste generation rate. Simultaneously, a high demand for the production of new electronic equipment has led to the scarcity of certain metals. In this context, many recent studies have focused on recovering certain metals from e-waste through the use of bioprocesses. Such recovery processes are based on the action of microorganisms that produce Fe(III) as an oxidant, in order to leach the copper contained in printed circuit boards. During the oxidation-reduction reaction between Fe(III) and metallic Cu, the color of the solution evolves from an initial reddish color, due to Fe(III), to a bluish-green color, due to the oxidized Cu. In this work, a hardware-software prototype is developed, through which the concentrations of the key analytes—Fe(III) and Cu(II)—can be determined in real time by monitoring the color of the solution. This is achieved through the use of a non-invasive system, taking into account the aggressiveness of the solutions used for the bioprocessing of electronic components. In the work presented herein, the evolution of the solution color during the bioprocessing of two different types of waste (i.e., electric cable and mobile phones) is analyzed and then compared with the results obtained for pure metallic copper. The results are validated through comparison of the predicted results with the outcomes of conventional procedures, including offline sampling and analysis of Cu(II) and Fe(III) through atomic absorption and UV-VIS spectroscopy, respectively. The developed monitoring system allows an algorithm to be designed that can fit the evolution of analyte concentrations without the need for sampling or the use of complex, tedious, and expensive analytic techniques. It is also worth noting that the monitoring system is not in direct contact with the solution (which is highly aggressive for the processing of el, This work was supported by the Spanish Agencia Estatal de Investigación Project Ref PID2020-117520RA-I00/AEI/10.13039/501100011033., Peer Reviewed, Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables, Postprint (published version)

Hydratisierte Metallionen spielen eine wichtige Rolle in Fachgebieten wie Chemie, Biologie, Geochemie und Chemieingenieurwesen. Studien an Clustern von mikrohydratisierten Metallionen in der Gasphase stellen ein Modellsystem dar, um deren Lösungsverhalten und chemische Reaktionen, wie Wasserstoffproduktion oder Korrosionsmechanismen, auf molekularer Ebene zu verstehen. Magnesium und Zink sind beides häufig vorkommende Elemente der Erdkruste und gehören zu den am meisten genutzten Materialien. Beide Elemente sind unentbehrlich für lebende Organismen. Magnesium spielt eine Schlüsselrolle in der photosynthetischen Funktion von Chlorophyll in Pflanzen. Zink findet häufige Verwendung als Schutz gegen Korrosion. Photodissoziationsexperimente an hydratisierten Magnesiumkationen [Mg(H_2O)_n ]^+, in einem Größenbereich von n=20–70, wurden unter Verwendung von UV/Vis Photodissoziationsspektroskopie, bei der es zu elektronischer Anregung kommt, für Photonenenergien zwischen 1,0–5,0 eV, durchgeführt. Hydratisierte Zinkmonomerkationen [Zn(H_2O)_n ]^+, für n=2–35 und hydratisierte Zinkdimerkationen [Zn_2 (H_2O)_n ]^+, für n=1-20, wurden unter Verwendung von Infrarot-Multiphotonendissoziations-spektoskopie untersucht, wobei die Region der O–H Streckschwingung in einem Wellenlängenbereich zwischen 2250–4000 cm^(-1) angeregt wurde. In beiden Fällen wurden die Experimente mit quantenchemischen Rechnungen begleitet und verglichen, welche mit Hilfe von Dichtefunktionaltheorie durchgeführt wurden., Hydrated metal ions play an important role in fields such as chemistry, biology, geochemistry and chemical engineering. Gas phase studies on microhydrated metal ion clusters provide a model system to understand solvation behavior and chemical reactions, like hydrogen production or corrosion mechanisms, on the molecular level. Magnesium and zinc are both abundant elements in the Earth's crust and are amongst the most used materials. Both are essential for live. Magnesium plays a key role in the photosynthetic function of chlorophyll in plants. Zinc is widely used as a protection against corrosion. Photodissociation experiments on hydrated magnesium cations [Mg(H_2O)_n ]^+, in a size range of n=20–70, have been performed by the use of UV/Vis photodissociation spectroscopy, involving electronic excitation, for photon energies between 1.0–5.0 eV. Hydrated zinc monomer cations [Zn(H_2O)_n ]^+, from n=2–35 and hydrated zinc dimer cations [Zn_2 (H_2O)_n ]^+, from n=1-20, were studied using infrared multiple photon dissociation spectroscopy, addressing the stretching region of the O–H vibration, in a wavelength range of 2250–4000 cm^(-1). In both cases experiments were accompanied by and compared with quantum chemical calculations, utilizing density functional theory., Thomas Johann Taxer, Kurzfassung in deutscher Sprache, Kumulative Dissertation aus drei Artikeln, In den Artikeln sind 2, n tiefgestellt, + ist hochgestellt, Dissertation Universität Innsbruck 2023

This paper is concerned with the problem of regularization by noise of systems of reaction–diffusion equations with mass control. It is known that strong solutions to such systems of PDEs may blow-up in finite time. Moreover, for many systems of practical interest, establishing whether the blow-up occurs or not is an open question. Here we prove that a suitable multiplicative noise of transport type has a regularizing effect. More precisely, for both a sufficiently noise intensity and a high spectrum, the blow-up of strong solutions is delayed up to an arbitrary large time. Global existence is shown for the case of exponentially decreasing mass. The proofs combine and extend recent developments in regularization by noise and in the Lp(Lq) -approach to stochastic PDEs, highlighting new connections between the two areas., Analysis

Among phenol-derived electrophiles, aryl sulfamates are attractive substrates since they can be employed as directing groups for C–H functionalization prior to catalysis. However, their use in C–N coupling is limited only to Ni catalysis. Here, we describe a Pd-based catalyst with a broad scope for the amination of aryl sulfamates. We show that the N-methyl-2-aminobiphenyl palladacycle supported by the PCyp2ArXyl2 ligand (Cyp = cyclopentyl; ArXyl2 = 2,6-bis(2,6-dimethylphenyl)phenyl) efficiently catalyzes the C–N coupling of aryl sulfamates with a variety of nitrogen nucleophiles, including anilines, primary and secondary alkyl amines, heteroaryl amines, N-heterocycles, and primary amides. DFT calculations support that the oxidative addition of the aryl sulfamate is the rate-determining step. The C–N coupling takes place through a cationic pathway in the polar protic medium.

Aquest treball té per objectiu general descriure els mètodes actuals de revaloració de plàstics per mitjà del reciclatge químic. Després d'un fonament teòric on s'exposen els conceptes bàsics sobre els plàstics i polímers, s'avança cap a l'estat de la qüestió. Aquest apartat emmarca la situació dins d'Espanya, realitzant primer una anàlisi crítica de la Llei 7/2022 sobre residus i sòls contaminats per a una economia circular, per avançar després cap a la descripció de l'estat d'aquesta tecnologia al país, enumerant les diferents empreses que actualment en disposen, així com els seus projectes futurs. A l'estat de la ciència i la tecnologia és on es desenvolupen els continguts plantejats en l'objectiu general del treball. Es desenvolupen tres processos principals: piròlisi (piròlisi tèrmica, piròlisi catalítica i co-piròlisi), solvolisi i gasificació. Es veuran processos on les matèries primeres són deixalles plàstiques de PP, LDPE, HDPE, PET, PLA i PC. Aquest apartat finalitza amb una introducció a l'avaluació del cicle de vida del reciclatge químic, per poder demostrar els beneficis mediambientals., El presente trabajo tiene por objetivo general describir los métodos actuales de revalorización de plásticos por medio del reciclaje químico. Luego de un fundamento teórico donde se exponen los conceptos básicos sobre los plásticos y los polímeros, se avanza hacia el estado de la cuestión. Este apartado enmarca la situación dentro de España, realizando primero un análisis crítico de la Ley 7/2022 sobre residuos y suelos contaminados para una economía circular, para luego avanzar hacia la descripción del estado de esta tecnología en el país, enumerando las diferentes empresas que actualmente disponen de la misma, así como sus proyectos futuros. En el estado de la ciencia y la tecnología es donde se desarrollan los contenidos planteados en el objetivo general del trabajo. Se desarrollan tres procesos principales: pirólisis (pirólisis térmica, pirólisis catalítica y co-pirólisis), solvolisis y gasificación. Se verán procesos donde las materias primas son desechos plásticos de PP, LDPE, HDPE, PET, PLA y PC. Este apartado se finaliza con una introducción a la evaluación del ciclo de vida del reciclaje químico, para poder demostrar sus beneficios medioambientales, The general objective of this work is to describe the current methods of revalorizing plastics through chemical recycling. After a theoretical foundation where the basic concepts of plastics and polymers are presented, it moves on to the state of the matter. This section frames the situation within Spain, first carrying out a critical analysis of Law 7/2022 on waste and contaminated soils for a circular economy, and then moving towards the description of the state of this technology in the country, listing the different companies that currently have it, as well as their future projects. The state of science and technology is where the contents raised in the general objective of the work are developed. Three main processes are developed: pyrolysis (thermal pyrolysis, catalytic pyrolysis and co-pyrolysis), solvolysis and gasification. The processes to be seen will have plastic waste as raw materials, such as PP, LDPE, HDPE, PET, PLA and PC. This section ends with an introduction to the evaluation of the life cycle of chemical recycling, in order to demonstrate its environmental benefits

Pneumatic actuators are extensively studied in soft robotics as they are facile, low-cost, scalable, robust and exhibit compliance similar to many systems found in nature. The challenge is to harness, high energy density, chemical, and biochemical reactions to generate sufficient pneumatic pressure for controlled and biocompatible actuation of soft systems. This study identifies and proposes a variety of gas evolution reactions (GERs) and gas consumption reactions (GCRs) as reversible power sources for soft robotic actuators. It marks the first successful coupling of both GER and GCR in actuating pneumatic soft actuators while controlling actuation over reaction rates and final pressure for efficient oscillating actuation. Furthermore, the research introduces a catalytic FDM filament with embedded platinum nanopartocles (PtNPs) for enhanced soft pneumatic actuation, improving catalytic activity and reusability compared to commercial and synthesised dispersed nanopowders. The synthesis and characterisation of sub-3 nm PtNPs in a polymeric matrix achieve higher catalytic activity by optimising the surface-to-volume ratio of the nanoparticles. The fabrication of 3D structures with catalytic properties using additive manufacturing enables complex geometries for diverse soft robotic applications. Moreover, an in-depth investigation of the photoreduction mechanism and in-situ generation of PtNPs in a thermoplastic polyurethane (TPU) matrix is conducted, providing insights for further development of catalytic materials. Creating high surface area structures enhances catalytic properties using the direct ink writing (DIW) method, expanding potential applications in soft pneumatic actuators. TPU Ninjaflex 3D-printed bellow-type pneumatic soft actuators demonstrate chemical resistance and mechanical suitability for coupling with the evaluated GERs and GCRs. The thesis highlights significant progress in coupling GERs and GCRs, paving the way for innovative pow

We review a class of gradient systems with dissipation potentials of hyperbolic-cosine type. We show how such dissipation potentials emerge in large deviations of jump processes, multi-scale limits of diffusion processes, and more. We show how the exponential nature of the cosh derives from the exponential scaling of large deviations and arises implicitly in cell problems in multi-scale limits. We discuss in-depth the role of tilting of gradient systems. Certain classes of gradient systems are tilt-independent, which means that changing the driving functional does not lead to changes of the dissipation potential. Such tilt-independence separates the driving functional from the dissipation potential, guarantees a clear modelling interpretation, and gives rise to strong notions of gradient-system convergence. We show that although in general many gradient systems are tilt-independent, certain cosh-type systems are not. We also show that this is inevitable, by studying in detail the classical example of the Kramers high-activation-energy limit, in which a diffusion converges to a jump process and the Wasserstein gradient system converges to a cosh-type system. We show and explain how the tilt-independence of the pre-limit system is lost in the limit system. This same lack of independence can be recognized in classical theories of chemical reaction rates in the chemical-engineering literature. We illustrate a similar lack of tilt-independence in a discrete setting. For a class of ‘two-terminal’ fast subnetworks, we give a complete characterization of the dependence on the tilting, which strongly resembles the classical theory of equivalent electrical networks.

Developing catalytic chemical processes for a sustainable future is a constant challenge involving different knowledge áreas (Sakakura et al., 2007; Yang et al., 2013; Götz et al., 2016; Tian et al., 2023; Yu et al., 2023). It requires multidisciplinary actions that include economic sectors, industry, society, and the environment (Lee et al., 2006; Corma et al., 2007; Naik et al., 2010; Ferreira Mota et al., 2022; Tafete and Habtu, 2023). Furthermore, catalytic chemical processes require constant evaluation to achieve greater sustainability, mainly when applied in industries or on a domestic scale (Chheda et al., 2007; Khodakov et al., 2007; Oh et al., 2016; Deng et al., 2023). Indeed, chemical catalysis is inherent in developing a sustainable future (Kondratenko et al., 2013; Deng et al., 2023). Chemical reactions are inseparable from our subject since they are applied in different processes, such as the preparation of fuels, food, drugs, and energy (Arcadi, 2008; Lima et al., 2022; Moreira et al., 2022; Sales et al., 2022; de Sousa et al., 2023; Faizan and Song, 2023; Nogueira et al., 2023). In this context, we include scientific research to help make these processes more sustainable. Moreover, consequently, it reduce the negative impact on the environment (Wang et al., 2023a; Zhu et al., 2023). Regarding chemical catalysis, reducing the amount of energy involved in the processes is fundamental (Roy et al., 2010; Yang et al., 2023a; Nogueira et al., 2023). This has a positive impact on reducing the use of polluting energy sources so that these systems can happen, such as the use of petroleum-derived fuels (Torborg and Beller, 2009; Catumba et al., 2023; Jafarian et al., 2023; Park and Kim, 2023). Furthermore, the greater need to use high temperature and pressure conditions increases energy consumption and, consequently, the production of waste that pollutes the environment (Singh et al., 2018; Djandja et al., 2023). Thus, chemical catalysis must seek to reduce the

Este trabajo de investigación propone a partir de una sólida fundamentación teórica, la aplicación de la enseñanza problematizada para el tema de “Los cambios químicos” de 4º curso de ESO (Educación Secundaria Obligatoria). Los contenidos son los exigidos en el currículum de la asignatura de Física y Química de dicho curso en el boletín oficial del estado (BOE). Tiene como objetivo principal el presentar una secuencia de actividades pensadas para la comprensión por parte del alumnado de las reacciones químicas, y todo en su contenido está orientado a la justificación de esta secuencia., This research work proposes, with a solid theoretical foundation, the application of problem-based teaching for the subject of “Chemical changes” in the 4th ESO (Educación Secundaria Obligatoria). The contents are those required in the curriculum of the subject of Physics and Chemistry of this course in the official state bulletin (BOE). Its main objective is to present a sequence of activities designed for students’ understanding of chemical reactions, and all its content is oriented towards the justification of this sequence.

We report the dimerization and oligomerization of ethylene using bis(phosphino)boryl supported Ni(II) complexes as catalyst precursors. By using alkylaluminum(III) compounds or other Lewis acid additives, Ni(II) complexes of the type (RPBP)NiBr (R = tBu or Ph) show activity for the production of butenes and higher olefins. Optimized turnover frequencies of 640 molethylene·molNi-1·s-1 for the formation of butenes with 41(1)% selectivity for 1-butene using (PhPBP)NiBr, and 68 molethylene·molNi-1·s-1 for butenes production with 87.2(3)% selectivity for 1-butene using (tBuPBP)NiBr, have been demonstrated. With methylaluminoxane as a co-catalyst and (tBuPBP)NiBr as the precatalyst, ethylene oligomerization to form C4 through C20 products was achieved, while the use of (PhPBP)NiBr as the pre-catalyst retained selectivity for C4 products. Our studies suggest that the ethylene dimerization is not initiated by Ni hydride or alkyl intermediates. Rather, our studies point to a mechanism that involves a cooperative B/Ni activation of ethylene to form a key 6-membered borametallacycle intermediate. Thus, a cooperative activation of ethylene by the Ni-B unit of the (RPBP)Ni catalysts is proposed as a key element of the Ni catalysis.

Siloxanes and silanols containing Si–H units are important building blocks for the synthesis of functionalized siloxane materials, and their synthesis is a current challenge. Herein, we report the selective synthesis of hydrosilanols, hydrosiloxanes, and silanodiols depending on the nature of the catalysts and the silane used. Two neutral ({MCl[SiMe2(o-C6H4PPh2)]2}; M = Rh, Ir) and two cationic ({M[SiMe2(o-C6H4PPh2)]2(NCMe)}[BArF4]; M = Rh, Ir) have been synthesized and their catalytic behavior toward hydrolysis of secondary silanes has been described. Using the iridium complexes as precatalysts and diphenylsilane as a substrate, the product obtained is diphenylsilanediol. When rhodium complexes are used as precatalysts, it is possible to selectively obtain silanediol, hydrosilanol, and hydrosiloxane depending on the catalysts (neutral or cationic) and the silane substituents

An evolution of a synthetic route leading to a successful enantioselective total synthesis of monoterpenoid indole alkaloid (+)-alstonlarsine A is represented. The unique 9-azatricyclo[4.3.1.03,8]decane core was assembled through an efficient domino sequence comprising enamine formation in situ, followed by intramolecular dearomative inverse-electron-demand Diels Alder reaction. The preparation of the tricyclic dihydrocyclohepta[b]indole key intermediate via the intramolecular Horner–Wadsworth–Emmons reaction required a development of a new general method for the introduction of the phosphonoacetate moiety into the indole C-2 position, through copper-carbenoid insertion. The modular nature of the represented synthetic approach makes it suitable for the synthesis of analogues with different substituents’ patterns.

An evolution of a synthetic route leading to a successful enantioselective total synthesis of monoterpenoid indole alkaloid (+)-alstonlarsine A is represented. The unique 9-azatricyclo[4.3.1.03,8]decane core was assembled through an efficient domino sequence comprising enamine formation in situ, followed by intramolecular dearomative inverse-electron-demand Diels Alder reaction. The preparation of the tricyclic dihydrocyclohepta[b]indole key intermediate via the intramolecular Horner–Wadsworth–Emmons reaction required a development of a new general method for the introduction of the phosphonoacetate moiety into the indole C-2 position, through copper-carbenoid insertion. The modular nature of the represented synthetic approach makes it suitable for the synthesis of analogues with different substituents’ patterns.

Referencias bibliográficas: • Alonso, M. J.,Ortiz, Y.. (2005). Del cuaderno de equipo al método de proyectos. Cuadernos de Pedagogía. 345. 62 • Balocchi, E.,Modak, B.,Martínez-M., M.,Padilla, K.,Reyes-C, F.,Garritz, A.. (2005). Aprendizaje cooperativo del concepto ‘cantidad de sustancia’ con base en la teoría atómica de Dalton y la reacción química. Parte I. El aprendizaje cooperativo. Anexo: cuadernillo ‘La reacción química y su representación’. Educación Química. 16. 469 • Balocchi, E.,Modak, B.,Martínez-M., M.,Padilla, K.,Reyes-C, F.,Garritz, A.. (2005). Parte II: Concepciones alternativas de ‘reacción química’ Anexo: cuadernillo ‘Masas atómicas relativas de los elementos’. Educación Química. 16. 550 • Balocchi, E.,Modak, B.,Martínez-M., M.,Padilla, K.,Reyes-C, F.,Garritz, A.. (2006). Parte III: Concepciones acerca de la ‘cantidad de sustancia’ y su unidad ‘el mol’. Anexo: Cuadernillo ‘Cantidad de sustancia’. Educación Química. 17. 14-32 • Carbonell, F.,Furió, C.. (1987). Opiniones de los adolescentes respecto del cambio sustancial en las reacciones químicas. Enseñanza de las ciencias. 5. 3-9 • Cooper, M. M.. (1995). Cooperative Learning. An Approach for Large Enrolment Courses. Journal of Chemical Education. 72. 162 • De Prada, F. I.,Cañas, A.,Caamaño, A.. (2015). Física y Química. ESO. Savia. Grupo SM Educación. • Dávila, M. A.,Cañada, F.,Sánchez, J.,Mellado, V.. (2016). Las emociones en el aprendizaje de física y química en educación secundaria. Causas relacionadas con el estudiante. Educación Química. 27. 217 • Dávila, M. A.,Cañada, F.,Sánchez, J.. (2017). Aprendizaje cognitivo y emocional de las reacciones químicas. Alambique. Didáctica de las Ciencias Experimentales. 90. 27-36 • De Ita Cisneros, M. A.,González Vergara, E.. (2005). ¿H2O igual a agua?: Una experiencia de aprendizaje colaborativo en el aula o el laboratorio. Educación Química. 16. 39-43 • De Vos, W.,Verdonk, A. H.. (1985). A New Road to Reactions. Journal of Chemical Education. 62. 238 • Diaz, En el presente trabajo se propone una secuencia didáctica para la enseñanza de las reacciones químicas en educación secundaria, que incluye dos actividades diferentes de aprendizaje cooperativo. La primera, para trabajar la diferencia entre cambio físico y cambio químico y, la segunda, para consolidar la parte experimental que también se ha llevado a cabo en el laboratorio. Un total de 43 estudiantes valoraron la experiencia y la metodología empleada mediante un cuestionario. Los resultados muestran que aproximadamente un 80% están a favor de emplear el modelo de aprendizaje con grupos cooperativos. No obstante, un 30% de los estudiantes señalan que hay que asegurar que todos los miembros de los equipos participen y realicen el trabajo asignado. La metodología cooperativa se podría emplear en la enseñanza de las reacciones químicas., In this research, we propose a didactic sequence for teaching chemical reactions in secondary education, which includes two different cooperative learning activities. The first one aims to work the differences between physical change and chemical change, and the second activity intends to consolidate the experimental job that was carried out in the laboratory. A total of 43 students completed a questionnaire to assess the experience and the methodology used. Results show that around 80% of the participants are willing to learn in cooperative groups, nevertheless 30% of students pointed out that teachers should encourage that each team member equally participates and shares the workload. Cooperative strategies might be useful for teaching chemical reactions., Depto. de Didáctica de las Ciencias Experimentales , Sociales y Matemáticas, Fac. de Educación, TRUE, pub

Se presenta una investigación de tipo cuasiexperimental, con estudiantes de primero de bachillerato, basada en la metodología de resolución de problemas por investigación (MRPI) de corte indagativo. Las situaciones problemáticas planteadas se contextualizan en la unidad didáctica Reacciones químicas y biomasa diseñada al efecto. Los resultados obtenidos a partir de las producciones de los estudiantes indican niveles de resolución muy elevados para todas las dimensiones competenciales científicas analizadas, con diferencias estadísticamente significativas respecto al momento inicial. Además, se compara la eficacia para resolver problemas cerrados de los estudiantes con otros de un grupo control que han trabajado con una metodología centrada en el entrenamiento de este tipo de tareas., A quasi-experimental type of research is presented, with first-year high school students, based on the problem-solving methodology as an investigation (PSMI). The problematic situations raised are contextualized in the didactic unit Chemical Reactions and Biomass designed for this purpose. The results obtained from the students' productions indicate very high levels of resolution for all the scientific competence dimensions analyzed, with statistically significant differences with respect to the initial moment. In addition, the effectiveness of solving closed problems of the students is compared with that of others in a control group working with a methodology focused on training these types of tasks.

In this paper, a clean process based on the steam-mediated reactions for simultaneous HCl and KCl production using the potassium (K)-containing phosphorous rock as a precursor is proposed. Through hydrochloric acid (HCl) leaching, not only the generation of H3PO4and CaCl2 (via further precipitation) were realized but also the acid-insoluble residue [phosphorous-rock slag (PS)] rich in elements, that is, K, Al, Si, and so on, in the form of microcline (KAlSi3O8) and quartz (SiO2) was obtained and became readily available for further HCl and KCl generation. Over 95 % of the elements, that is, K, Al, and Si, come into the final products, and the overall acid consumption (based on HCl) is significantly reduced (90%) due to recovery of acids. The impacts of the key operational parameters such as temperature, duration, and reagent impregnate ratio were rigorously analyzed via a supervised machine learning approach, and the optimal conditions were determined [reaction temperature, X1, 850 °C; reaction duration, X2, 40 min; and impregnate ratio (PS over CaCl2), X3, 2.5] with approximately ± 10% uncertainties. Thermodynamic analysis indicates that the introduction of steam to PS + CaCl2not only enhances the chemical potential for the formation of HCl and KCl but also provides the transport advantage in continuously removing the generated products, that is, HCl and KCl, out of the system. Molecular simulation indicates that the presence of both steam and SiO2in the PS matrix plays critical roles in decomposing PS + CaCl2at high temperature. The shrinking core model shows that both the intrinsic kinetics and transport are influential with the activation energy being around 14.63 kJ/mol. The potential reaction pathway is postulated.

A plethora of 6-(hetero)aryl C-C and C-N bonded tacrine analogues has been made accessible by employing palladium mediated (Suzuki-Miyaura, Heck, Sonogashira, Stille and Buchwald) cross-coupling reactions, starting from either halogenated or borylated residues. The successful use of Pd(dppf)Cl2·CH2Cl2 as a common catalytic system in realizing all these otherwise challenging transformations is the highlight of our optimized protocols. The analogues thus synthesized allow the available chemical space around the C-6 of this biologically relevant tacrine core to be explored. The in silico docking studies of the synthesized compounds were carried out against the acetylcholinesterase (AChE) enzyme. The hepatotoxicity studies of these compounds were done against complexes of CYP1A2 and CYP3A4 proteins with known inhibitors like 7,8-benzoflavone and ketoconazole, respectively. © 2022 The Royal Society of Chemistry.

A convenient synthetic approach to asymmetrically functionalized 1,3-di(2-pyridyl)benzenes starting from 3-(3-bromophenyl)-1,2,4-triazines using sequential aza-Diels–Alder reactions and Stille cross-coupling is reported. Photophysical properties of the obtained compounds are studied. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

Here, we report that the reaction of enaminones, from a class of azole series, with sulfonyl azides leads to a difficult-to-separate mixture of two pairs of compounds: (1) 4-azoloyl-NH-1,2,3-triazoles with sulfonamides and (2) azolyl diazoketones with N-sulfonamidines, as a result of the implementation of two competing reactions. On one hand, the electron-donating methyl or methoxy group in the aryl para-position of arylsulfonyl azides favors the production of NH-1,2,3-triazoles together with sulfonamides. On the other hand, the use of highly electrophilic 4-nitrophenylsulfonyl azide promotes the formation of diazoketones and sulfonamidines. It is shown that the direction of each reaction is not only controlled by the nature of the initial enaminones and sulfonyl azides but also depends on the tested solvent. The problem of removing sulfonamides and amidines from the desired products was solved for the first time using new water-soluble enaminones. Based on the experimental and computational studies, the factors contributing to the selective course of alternative reactions were identified, and methods for the synthesis of azoloyl-NH-1,2,3-triazoles and azolyl diazoketones were developed. Density functional theory (DFT) results have shown that the 1,3-dipolar cycloaddition is totally driven toward one single regioisomer with a high asynchronous bond formation, and the introduction of an electron-deficient group in sulfonyl azides induces faster cycloaddition. Additionally, DFT calculations were used to gain further mechanistic insights on the reaction studied here. © 2022 American Chemical Society. All rights reserved.

We report on the formation of counterpropagating density gradients in poly([2-dimethylaminoethyl] methacrylate) (PDMAEMA) brushes featuring spatially varying quaternized and betainized units. Starting with PDMAEMA brushes with constant grafting density and degree of polymerization, we first generate a density gradient of quaternized units by directional vapor reaction involving methyl iodide. The unreacted DMAEMA units are then betainized through gaseous-phase betainization with 1,3-propanesultone. The gas reaction of PDMAEMA with 1,3-propanesultone eliminates the formation of byproducts present during the liquid-phase modification. We use the counterpropagating density gradients of quaternized and betainized PDMAEMA brushes in antibacterial and antifouling studies. Completely quaternized and betainized brushes exhibit antibacterial and antifouling behaviors. Samples containing 12% of quaternized and 85% of betainized units act simultaneously as antibacterial and antifouling surfaces.

Metallurgical converters such as the argon–oxygen decarburization (AOD) converter generally utilize gas blowing for the mixing and refinement of liquid steel. Due to the harsh environment of the complex and opaque system, it is common practice to study the stirring of the process through physical and numerical models. Effective mixing in the bath has an important role in refinement such as decarburization and has been vividly studied before. However, high-temperature chemical reactions that also play a major role are sparsely investigated. With the help of modeling, a computational fluid dynamics model coupled with chemical reactions is developed, allowing the study of both dynamic fluid transport and chemical reactions. Herein, the chemical reactions for a single gas bubble in the AOD are investigated. The study shows that a 60 mm oxygen gas bubble rapidly reacts with the melt and is saturated with carbon in 0.2–0.25 s at low-pressure levels. The saturation time is affected by the pressure and the composition of the injected gas bubble. The impact of ferrostatic pressure on the reactions is more significant at larger depth differences., QC 20230328

We report on the formation of counterpropagating density gradients in poly([2-dimethylaminoethyl] methacrylate) (PDMAEMA) brushes featuring spatially varying quaternized and betainized units. Starting with PDMAEMA brushes with constant grafting density and degree of polymerization, we first generate a density gradient of quaternized units by directional vapor reaction involving methyl iodide. The unreacted DMAEMA units are then betainized through gaseous-phase betainization with 1,3-propanesultone. The gas reaction of PDMAEMA with 1,3-propanesultone eliminates the formation of byproducts present during the liquid-phase modification. We use the counterpropagating density gradients of quaternized and betainized PDMAEMA brushes in antibacterial and antifouling studies. Completely quaternized and betainized brushes exhibit antibacterial and antifouling behaviors. Samples containing 12% of quaternized and 85% of betainized units act simultaneously as antibacterial and antifouling surfaces.

The development of catalysts relying on earth-abundant st-row transition metals is highly desirable. The unique electronic properties of 1st-row transition metal would give rise to more unexpected and surprising reactivities for homogeneous hydrogenation reactions. In addition, novel hydrogenation mechanisms distinguished from the classical “inner-sphere” and “outer-sphere” mechanisms are needed for the hydrogenation of some challenging substrates. In this thesis, we focus on the understanding of Co chemistry and the chemoselective issues related to the hydrogenation of C=C and C=O catalyzed by Co complexes (Chapters 2-5). Furthermore, we discussed two interesting examples of hydrogenation including (NHC)Cu(I)H-guanidine bifunctional catalysis for hydrogenation of esters (Chapter 6) and ionic hydrogenation of oxocarbenium ions (Chapter 7). Co(I), as one of the 1st-row transition metals with a d8 electron configuration, prefers 5-coordinated Co (I) complexes due to its relatively smaller d-p gap when compared to other heavier d8 transition metal centers. When Co(I) combines with a carbene ligand, it was found that trans-dihydride complexes could be stabilized, which are important intermediates frequently proposed in transition metal catalyzed hydrogenation reactions. Our theoretical studies indicate that via an “inner-sphere” mechanism, the Co(I) catalyst [Co(I)(H2)(PR3)] was able to selectively hydrogenate C=C but not C=O, while the Co(I)/tetraphosphine catalyst [(P4N2)Co(I)H] catalyzed selective reduction of C=O rather than the C=C via an “outer-sphere” mechanism. Besides the classical “inner-sphere” and “outer-sphere” mechanisms, novel hydrogenation mechanisms are interesting and can give surprising results and have the potential for the hydrogenation of challenging substrates. Related to this aspect, this thesis also covers two novel hydrogenation mechanisms: (1) a

A method for the use of vinyl epoxides in catalytic allylboration of alkynes is described. This transformation allows for the synthesis of bifunctional skipped dienes bearing both an allylic alcohol and an alkenylboronate from simple starting materials with high regio- and stereoselectivity. These two functionalities provide these products with highly versatile reactivity, as shown by their stereocontrolled conversion into cyclic boron compounds and polyenes

The equilibrium calculation of a reactive mixture under the phase-fraction specification, including saturation point calculation and phase envelope calculation, is desirable for the relevant process analysis and simulation. We developed the saturation RAND formulation and the corresponding algorithms for these phase-fraction specification problems. Two types of phase fraction were distinguished: the component-based one and the element-based one, which led to different constraint equations in the formulation. We further introduced element-based partition coefficients to cross the critical point of a reactive mixture in the phase envelope construction. In addition, the general formulation for reactive mixtures can be reduced and used for calculating simpler non-reactive mixtures. We illustrated the robustness and efficiency of our algorithms using four examples: Pxy diagrams for CO2-NaCl brine, a solid-liquid Tx diagram for MgCl2-water, a PT phase envelope for a reactive mixture with the alkene hydration reaction, and a PT phase envelope for a non-reactive hydrocarbon mixture.

In this paper, a clean process based on the steam-mediated reactions for simultaneous HCl and KCl production using the potassium (K)-containing phosphorous rock as a precursor is proposed. Through hydrochloric acid (HCl) leaching, not only the generation of H3PO4and CaCl2 (via further precipitation) were realized but also the acid-insoluble residue [phosphorous-rock slag (PS)] rich in elements, that is, K, Al, Si, and so on, in the form of microcline (KAlSi3O8) and quartz (SiO2) was obtained and became readily available for further HCl and KCl generation. Over 95 % of the elements, that is, K, Al, and Si, come into the final products, and the overall acid consumption (based on HCl) is significantly reduced (90%) due to recovery of acids. The impacts of the key operational parameters such as temperature, duration, and reagent impregnate ratio were rigorously analyzed via a supervised machine learning approach, and the optimal conditions were determined [reaction temperature, X1, 850 °C; reaction duration, X2, 40 min; and impregnate ratio (PS over CaCl2), X3, 2.5] with approximately ± 10% uncertainties. Thermodynamic analysis indicates that the introduction of steam to PS + CaCl2 not only enhances the chemical potential for the formation of HCl and KCl but also provides the transport advantage in continuously removing the generated products, that is, HCl and KCl, out of the system. Molecular simulation indicates that the presence of both steam and SiO2 in the PS matrix plays critical roles in decomposing PS + CaCl2 at high temperature. The shrinking core model shows that both the intrinsic kinetics and transport are influential with the activation energy being around 14.63 kJ/mol. The potential reaction pathway is postulated.

[Resumen] La robótica médica ha pasado de ser el futuro a estar entre nosotros en nuestro día a día. Existe una robótica médica más disruptiva, y con menos uso, por el momento, la microrrobótica. Existen multitud de aproximaciones a la hora de realizar un microrrobot. En este trabajo hemos realizado el modelo matemático inicial y el diseño de dos controladores para controlar la velocidad de un microrrobot autónomo movido por cabeceo con un flagelo pasivo acoplado. Mediante Simulink se han realizado estudios del modelo con distintos parámetros de entrada (simulando el empuje realizado mediante reacciones químicas) y el control de su velocidad. Se ha obtenido un modelo inicial que servirá de punto de partida para un modelo más completo. Además se realizó un prototipo funcional a escala., [Abstract] Medical robotics has gone from being the future to being part of our daily lives. There is a more disruptive medical robotics, and with less use, for the moment, microrobotics. There are a multitude of approaches when it comes to making a microrobot. In this work we have carried out the initial mathematical model and the design of two controllers to control the speed of an autonomous pitch-driven microrobot with a passive flagellum attached. Simulink has been used to study the model with different input parameters simulating the thrust produced by chemical reactions) and to control its speed. An initial model has been obtained that will serve as a starting point for a more complete model. In addition, a functional prototype was made to scale.

Random walk methods are particularly well suited for modeling (anomalous) transport processes in complex systems, from heterogeneous porous domains to fractured rocks. Taking full advantage of their multi-scale attributes, these methods can be integrated into multi-scale modeling strategies where they are used for (i) performing small-scale simulations with a high level of description of the heterogeneities, (ii) defining statistical functions that describe these heterogeneities at a larger scale, and (iii) providing upscaled descriptions of the processes while taking into account the impact of the small-scale heterogeneities. In this work, we define such a strategy considering (i) structural heterogeneities with heterogeneous porosity fields incorporated into fracture-matrix systems and (ii) the reactivity of the system with chemical reactions that are not restricted to linear first-order reactions as it is the case in existing upscaled formulations. To this end, we develop two new modeling methods: the Reactive-Time Domain Random Walk (R-TDRW) and Upscaled Reactive TDRW (UR-TDRW) approaches at small and large scale, respectively. The numerical methods and multi-scale strategy are presented with a general formulation and applied to single-species transport and reaction in fracture-matrix systems. We analyze the impact of different levels of structural heterogeneities, and the impact of the reactivity, on the breakthrough curves computed at both scales and on the statistical functions that are used in the multi-scale strategy. This strategy is validated by demonstrating the good agreement between the results obtained at different scales, showing promising applications for future work in large-scale fracture networks.

The need to understand chemistry through data-driven analysis from a comprehensive collection of reaction data has long been recognized, and the development of chemical reaction databases has been conducted for decades, including commercial databases such as Reaxys, Scifinder, or Web of Science and open-source database like the Open Reaction Database. As a result, exploiting information in this large-scale database could accelerate the process of addressing challenging chemistry problems. Recent developments in big data and machine learning have revolutionized approaches for analyzing chemical data, and successful applications of these techniques have significantly advanced the research in chemical reactions, including reaction classification, product prediction, yield estimation, and synthesis planning. In recent years, homogeneous nickel catalysis has been extensively studied in academia and industry. Remarkable advances have been made for many valuable reactions by using nickel as an effective catalyst, owing to its unique reactivity and cost efficiency. It would be beneficial to prepare a dataset to analyze this field from a fundamental point of view and provide more insight into the nickel-catalyzed reactions. We collected and analyzed a comprehensive dataset containing important papers in the field of C-O bond activation cross-coupling reactions and developed data mining tools to accelerate similar studies in the future.

Producción Científica, The modulus build-up and relative density evolution during the reactive foaming of four standard polyurethane formulations was monitored in-situ by Dynamic Mechanical Analysis (DMA) with a customised set-up in parallel plate geometry. The modulus increased from 0.01 MPa in the first minutes to over 1.2 MPa within 20 min. The set-up also enabled the recording of vitrification followed by curing times. These typically occur within 3 min of each other. The results of DMA are corroborated by measurements of the reaction kinetics with Infrared Spectroscopy. This goes to show that the modulus remains nearly unchanged during the stage of swiftest isocyanate conversion, while the point of gel conversion is accompanied by their increase., Junta de Castilla y León (grant VA202P20), Ministerio de Ciencia, Innovación y Universidades (grant RTI2018-098749-B-I00)

Direct C(sp2)-H functionalization of the endocyclic azomethine and aldonitrone moieties in non-aromatic azaheterocycles has established itself as a promising methodology over the last decade. Transition metal-catalyzed cross-coupling reactions, α-metalation-electrophile quenching protocols, and (metal-free) nucleophilic substitution of hydrogen reactions (SNH) are the major routes applied on cyclic imines and their derivatives. In this overview, we show the tangible progress made in this area during the period from 2008 to 2020. This journal is © The Royal Society of Chemistry.

A straightforward, user-friendly, efficient protocol for the one pot, ZnI2-catalyzed allenylation of terminal alkynes with pyrrolidine and ketones, toward trisubstituted allenes, is described. Trisubstituted allenes can be obtained under either conventional heating or microwave irradiation conditions, which significantly reduces the reaction time. A sustainable, widely available, and low-cost metal salt catalyst is employed, and the reactions are carried out under solvent-free conditions. Among others, synthetically valuable allenes bearing functionalities such as amide, hydroxyl, or phthalimide can be efficiently prepared. Mechanistic experiments, including kinetic isotope effect measurements and density functional theory (DFT) calculations, suggest a rate-determining [1,5]hydride transfer during the transformation of the intermediate propargylamine to the final allene.

Producción Científica, The modulus build-up and relative density evolution during the reactive foaming of four standard polyurethane formulations was monitored in-situ by Dynamic Mechanical Analysis (DMA) with a customised set-up in parallel plate geometry. The modulus increased from 0.01 MPa in the first minutes to over 1.2 MPa within 20 min. The set-up also enabled the recording of vitrification followed by curing times. These typically occur within 3 min of each other. The results of DMA are corroborated by measurements of the reaction kinetics with Infrared Spectroscopy. This goes to show that the modulus remains nearly unchanged during the stage of swiftest isocyanate conversion, while the point of gel conversion is accompanied by their increase., Junta de Castilla y León (grant VA202P20), Ministerio de Ciencia, Innovación y Universidades (grant RTI2018-098749-B-I00)

A straightforward, user-friendly, efficient protocol for the one pot, ZnI2-catalyzed allenylation of terminal alkynes with pyrrolidine and ketones, toward trisubstituted allenes, is described. Trisubstituted allenes can be obtained under either conventional heating or microwave irradiation conditions, which significantly reduces the reaction time. A sustainable, widely available, and low-cost metal salt catalyst is employed, and the reactions are carried out under solvent-free conditions. Among others, synthetically valuable allenes bearing functionalities such as amide, hydroxyl, or phthalimide can be efficiently prepared. Mechanistic experiments, including kinetic isotope effect measurements and density functional theory (DFT) calculations, suggest a rate-determining [1,5]hydride transfer during the transformation of the intermediate propargylamine to the final allene.

The Jahn–Teller (JT) theorem constitutes one of the most fundamental concepts in chemistry. In transition-element chemistry, the 3d4 and 3d9 configurations in octahedral complexes are particularly illustrative, where a distortion in local geometry is associated with a reduction of the electronic energy. However, there has been a lasting debate about the fact that the octahedra are found to exclusively elongate. In contrast, for Na9Bi5Os3O24, the octahedron around Os6+(5d2) is heavily compressed, lifting the degeneracy of the t2g set of 5d orbitals such that in the sense of a JT compression a diamagnetic ground state results. This effect is not forced by structural constraints, the structure offers sufficient space for osmium to shift the apical oxygen atoms to a standard distance. The relevance of these findings is far reaching, since they provide new insights in the hierarchy of perturbations defining ground states of open shell electronic systems. © 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.

Producción Científica, The modulus build-up and relative density evolution during the reactive foaming of four standard polyurethane formulations was monitored in-situ by Dynamic Mechanical Analysis (DMA) with a customised set-up in parallel plate geometry. The modulus increased from 0.01 MPa in the first minutes to over 1.2 MPa within 20 min. The set-up also enabled the recording of vitrification followed by curing times. These typically occur within 3 min of each other. The results of DMA are corroborated by measurements of the reaction kinetics with Infrared Spectroscopy. This goes to show that the modulus remains nearly unchanged during the stage of swiftest isocyanate conversion, while the point of gel conversion is accompanied by their increase., Junta de Castilla y León (grant VA202P20), Ministerio de Ciencia, Innovación y Universidades (grant RTI2018-098749-B-I00)

Detta examensarbete syftar till att utveckla ett nytt sätt att använda betong för inredningsändamål. Betong har alltid använts i större byggnader, infrastruktur och andra kategorier. Nyligen började den moderna inredningen använda betong inomhus, till exempel som bänkskiva eller som en hylla. Arbetet fokuserar på en huvudfråga: Är betong ett bra materialval för inredning? För att besvara denna fråga bestämdes några punkter för att komma till huvudfrågan. Följande punkter behövde testat och analyserad för att komma till svaren: - Beräkna och testa betongens hållfasthet - Testa slagtålighet - Analysera hur betong reagerar med kemikalier med olika pH-värde - Förhållandet mellan miljö och betong - Studera produktionen av betong Laborationstest, litteraturskällor och fältstudier användes som metoder för att få ett resultat av ovan nämnda punkter. Resultaten visar att betong kan användas som inredningsändamål och kan användas i större utsträckning än vad som är fallet idag. Sammanfattningsvis är betong ett bra material som används för inredningsändamål och den framtida tekniken kommer att minska koldioxidutsläppen som följer med produktionen av betongen. Det kommer att göra betong ännu bättre som material att använda i framtiden., The following thesis aims to develop a new way to use concrete as interior material. Concrete has always been used in larger scale buildings, infrastructure and in other categories. Recently the modern interior design started to use concrete indoors for example as countertop or as a shelf. This thesis focuses on one main question: is concrete a good material choice for interior use. To answer that question, we decided to have sub questions to help to get to the main question. The following questions needed test and analysis methods to get to the answers: - Calculate and test the strength of concrete - Test impact resistance - Analyze how concrete reacts with chemicals with different PH-values - Study the production of concrete - Relation between environment and concrete Lab tests, literature sources, and field studies was used as methods to answer those questions. The results shows that concrete can be utilized as interior material and can be used to a greater extent than is the case today. In conclusion concrete is a good material as used for interior purposes and the future technology will decrease carbon dioxide emissions that comes with production of the concrete. That will make concrete even better as material to use in the future.

In this paper, we compare the most popular Atom-to-Atom Mapping (AAM) tools: ChemAxon,([1]) Indigo,([2]) RDTool,([3]) NameRXN (NextMove),([4]) and RXNMapper([5]) which implement different AAM algorithms. An open-source RDTool program was optimized, and its modified version ("new RDTool") was considered together with several consensus mapping strategies. The Condensed Graph of Reaction approach was used to calculate chemical distances and develop the "AAM fixer" algorithm for an automatized correction of erroneous mapping. The benchmarking calculations were performed on a Golden dataset containing 1851 manually mapped and curated reactions. The best performing RXNMapper program together with the AMM Fixer was applied to map the USPTO database. The Golden dataset, mapped USPTO and optimized RDTool are available in the GitHub repository https://github.com/Laboratoire-de-Chemoinformatique.

Currently, herbs recognition system has become a promising method to identify herbs species. Misuse of herbal medicine can cause serious health problems due to toxicological effects of phytochemical. As a result, a system that able to distinguish the types of herbs is needed. Most herbs recognition systems available in the market are dependent on experts. In this research, the concern is to identify the herbs compounds within the same group species where the physical appearance and aroma are similar. The work mainly focuses on herbs recognition systems that intended for researchers and medical practitioners use without the need for experts. The study is mainly based on chemical and physical properties as well as the combination of both. Hence, three feature extraction methods for herbs recognition system based on chemical and physical properties of herbs are presented. Electronic Nose (E-Nose) devices have been used extensively to differentiate and characterize the herb species based on their unique odor. Electrical signal generated from the gas sensor array is one of the physical properties studied. Then, a Gas Chromatography-Mass Spectrometry (GCMS) device is utilized to extract the chemical compound of herbs. The first feature extraction technique in this research is Principal Component Analysis (PCA) and selected feature based on electrical signal, however it is an unsupervised learning. Thus, Multiple Discriminant Analysis (MDA) is proposed as the second feature extraction technique. MDA is one of the supervised learning techniques to replace PCA. The third feature extraction technique is proposed to develop an automated GCMS system that differentiates the herbs species from the major volatile compounds. The Weighted Histogram Analysis Method (WHAM) is proposed to make use of both major and minor volatile compounds in GCMS herbs recognition system. Fusion techniques have been extensively studied on multisensory environments. Comparison between system with and w

Manganese complexes have been considered as a cheap and readily available alternative to commonly used precious metal catalysts in C–C bond coupling reactions. Although high-valent Mn aryl intermediates have been proposed in such reactions, a mechanistic understanding of possible organometallic intermediates in Mn-mediated C–C coupling is still lacking due to their high reactivity. We report the synthesis of stable, isolable Mn(III) aryl complexes obtained by oxidative addition of aryl bromide or aryl chloride. These complexes react with a range of organometallic alkylating or arylating reagents (alkyl and aryl Grignard reagents, MeLi, ZnMe2) to undergo C(sp2)–C(sp3) or C(sp2)–C(sp2) bond coupling, and a preliminary catalytic system could be demonstrated. The reagent scope and yield of the C(sp2)–C(sp3) coupled product can further be increased by addition of TEMPO as an oxidant, generating alkyl radicals., source:https://pubs.acs.org/doi/10.1021/acs.organomet.1c00047

In this article, we consider cross-validation of the quantitative structure-property relationship models for reactions and show that the conventional k-fold cross-validation (CV) procedure gives an `optimistically' biased assessment of prediction performance. To address this issue, we suggest two strategies of model cross-validation, `transformation-out' CV, and `solvent-out' CV. Unlike the conventional k-fold cross-validation approach that does not consider the nature of objects, the proposed procedures provide an unbiased estimation of the predictive performance of the models for novel types of structural transformations in chemical reactions and reactions going under new conditions. Both the suggested strategies have been applied to predict the rate constants of bimolecular elimination and nucleophilic substitution reactions, and Diels-Alder cycloaddition. All suggested cross-validation methodologies and tutorial are implemented in the open-source software package CIMtools (https://github.com/cimm-kzn/CIMtools).

Producción Científica, The modulus build-up and relative density evolution during the reactive foaming of four standard polyurethane formulations was monitored in-situ by Dynamic Mechanical Analysis (DMA) with a customised set-up in parallel plate geometry. The modulus increased from 0.01 MPa in the first minutes to over 1.2 MPa within 20 min. The set-up also enabled the recording of vitrification followed by curing times. These typically occur within 3 min of each other. The results of DMA are corroborated by measurements of the reaction kinetics with Infrared Spectroscopy. This goes to show that the modulus remains nearly unchanged during the stage of swiftest isocyanate conversion, while the point of gel conversion is accompanied by their increase., Junta de Castilla y León (grant VA202P20), Ministerio de Ciencia, Innovación y Universidades (grant RTI2018-098749-B-I00)

Detta examensarbete syftar till att utveckla ett nytt sätt att använda betong för inredningsändamål. Betong har alltid använts i större byggnader, infrastruktur och andra kategorier. Nyligen började den moderna inredningen använda betong inomhus, till exempel som bänkskiva eller som en hylla. Arbetet fokuserar på en huvudfråga: Är betong ett bra materialval för inredning? För att besvara denna fråga bestämdes några punkter för att komma till huvudfrågan. Följande punkter behövde testat och analyserad för att komma till svaren: - Beräkna och testa betongens hållfasthet - Testa slagtålighet - Analysera hur betong reagerar med kemikalier med olika pH-värde - Förhållandet mellan miljö och betong - Studera produktionen av betong Laborationstest, litteraturskällor och fältstudier användes som metoder för att få ett resultat av ovan nämnda punkter. Resultaten visar att betong kan användas som inredningsändamål och kan användas i större utsträckning än vad som är fallet idag. Sammanfattningsvis är betong ett bra material som används för inredningsändamål och den framtida tekniken kommer att minska koldioxidutsläppen som följer med produktionen av betongen. Det kommer att göra betong ännu bättre som material att använda i framtiden., The following thesis aims to develop a new way to use concrete as interior material. Concrete has always been used in larger scale buildings, infrastructure and in other categories. Recently the modern interior design started to use concrete indoors for example as countertop or as a shelf. This thesis focuses on one main question: is concrete a good material choice for interior use. To answer that question, we decided to have sub questions to help to get to the main question. The following questions needed test and analysis methods to get to the answers: - Calculate and test the strength of concrete - Test impact resistance - Analyze how concrete reacts with chemicals with different PH-values - Study the production of concrete - Relation between environment and concrete Lab tests, literature sources, and field studies was used as methods to answer those questions. The results shows that concrete can be utilized as interior material and can be used to a greater extent than is the case today. In conclusion concrete is a good material as used for interior purposes and the future technology will decrease carbon dioxide emissions that comes with production of the concrete. That will make concrete even better as material to use in the future.