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Thermochemistry - Science topic

Thermochemistry is the study of the energy and heat associated with chemical reactions and/or physical transformations.
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Publications related to Thermochemistry (8,407)
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Article
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There is an urgent demand for novel energetic materials with improved performance to serve as oxygen suppliers (oxidizers) and high-energy additives. Synthesis and characterization of compound that combines both of the above roles, bis-(2-difluoroamino-2,2-dinitroethyl)nitramine (1), is reported. 1 was synthesized by difluor-oamination of bis(2,2-d...
Conference Paper
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Se presenta un código termoquímico (en adelante Combustion Toolbox, CT) para el cálculo de problemas de combustión gaseosa con especies condensadas, choques reactivos y no reactivos, descomposición exotérmica de materiales energéticos y rendimiento teórico de cohetes. En particular, se exponen dos de los cuatro módulos que lo componen: CT-EXPLO y C...
Article
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The Ga-In-Te alloy is one of the promising thermoelectric materials and its eutectic compositions can be expected to show improved thermoelectric behavior. In order to find the possible eutectic compositions in the ternary system, the thermodynamic modeling approach was considered based on the Computer Coupling of Phase Diagrams and Thermochemistry...
Article
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Double-hybrid density functional theory (DHDFT) offers a pathway to accuracy approaching composite wavefunction approaches such as G4 theory. However, the Gorling−Levy second-order perturbation theory (GLPT2) term causes them to partially inherit the slow ∝L −3 (with L the maximum angular momentum) basis set convergence of correlated wavefunction m...
Preprint
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Dihydroisobenzofuran heterocycle is a structural motif found in a number of medications with antitumour, antidiabetic, and antibacterial activities. It's also found in a slew of natural substances, most notably fungus metabolites, which have been shown to possess credible radical scavenging activity. Density functional theory studies on three diffe...
Article
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The dynamic response of structural elements subjected to blast loading is a problem of growing interest in the field of defense and security. In this work, a novel computational tool for the rapid evaluation of the effects of explosions, hereafter referred \reved{to} as SimEx, is presented and discussed. The classical correlations for the reference...
Preprint
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The structure, stability, and intermolecular interactions in SO3-(H2O) n (n = 1 -7) clusters were investigated using density functional and wave functional methods. The putative global minimum shows the SO3molecule tends to be on the surface water clusters. The increase in the number of water molecules chalcogen bond distance between water molecule...
Research Proposal
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CEA develops the PLEIADES software environment in cooperation with EDF and Framatome to simulate fuel elements behavior under normal and off-normal conditions [1]. PLEIADES can be viewed as a fuel performance code based on a multidimensional and on a multiphysics approach. ALCYONE, the PLEIADES code dedicated to PWRs fuel elements, already provides...
Article
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In pursuit of high-energy density sodium insertion materials, polyanionic frameworks can be designed with tuneable high-voltage operation stemming from inductive effect. Alluaudite Na2Fe2(SO4)3 polysulfate forms one such earth-abundant compound registering the highest Fe³⁺/Fe²⁺ redox potential (ca. 3.8 V vs. Na/Na⁺). While this SO4-based system exh...
Article
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In light of reducing carbon emissions and the tension on non-renewable energy sources, heat pumps are being investigated as an alternative to fossil-fuel-dependent energy converters in heat demanding applications. On the basis of the impactful results the authors obtained in previous research around the potential of using reactive fluids–instead of...
Preprint
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Silicate vapors play a key role in planetary evolution, especially dominating early stages of rocky planet formation through outgassed magma ocean atmospheres. Our open-source thermodynamic modeling software "VapoRock" combines the MELTS liquid model (Ghiorso et al. 1995) with gas-species properties from multiple thermochemistry tables (e.g. Chase...
Article
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Molecular hydrogen (H2) is now considered among the most prominent substitute for fossil fuels. The environmental impacts of a hydrogen economy have received more attention in the last years, but still, the knowledge is relatively poor. In this work, the reaction of H2 with NO3 radical (the dominant night-time detergent of the atmosphere) is studie...
Article
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The structure, thermodynamic parameters, and the character of thermal motion in octamethylcyclotetrasiloxane (D4) were investigated using the combination of experimental (single-crystal X-ray diffraction, thermochemistry) and theoretical (density functional theory calculations, ab initio molecular dynamics and metadynamics) methods. Single crystals...
Conference Paper
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O Brasil está entre os quatro maiores produtores mundiais de coco verde ou coco de praia. Todavia, tal cenário contribui com o descarte inapropriado de cascas de coco, ocasionando riscos socioambientais, bem como a contaminação de solos, águas superficiais e subterrâneas. Paralelamente, salienta-se o cenário de algumas cidades litorâneas brasileira...
Preprint
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Volcanism is a major and long-term source of volatile elements such as C and H to Earth's atmosphere, likely has been to Venus's atmosphere, and may be for exoplanets. Models simulating volcanic growth of atmospheres often make one of two assumptions: either that atmospheric speciation is set by the high temperature equilibrium of volcanism; or, th...
Article
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The following article discusses the antioxidant properties of mandelic acid and its hydroxy and methoxy derivatives. The antioxidant capacity of these compounds is determined by DPPH, FRAP, CUPRAC and ABTS. The mechanisms underlying the antioxidant properties are described by BDE, IP, PDE, ETE and PA calculation method values and referenced to expe...
Article
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Decarbonylation reactions of acetyl metal carbonyls, in particular of organocobalt compounds, and of amides are discussed in view of stabilization/resonance energies. It is found that the archetypal acetylcobalt tetracarbonyl, CH3C(O)Co(CO)4, has ca. 25 kJ mol⁻¹ stabilization, while the corresponding phthalimido- and phenoxy-substituted species hav...
Article
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A comparison of computed 19F NMR chemical shifts and experiment provides evidence for large specific solvent effects for fluoride‐type anions interacting with the σ*(C−H) orbitals in organic solvents like MeCN or CH2Cl2. We show this for systems ranging from the fluoride ion and the bifluoride ion [FHF]− to polyhalogen anions [ClFx]−. Discrepancies...
Article
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Electrospray ionization mass spectrometry (ESI-MS) is a powerful label-free assay for detecting noncovalent biomolecular complexes in vitro and is increasingly used to quantify binding thermochemistry. A common assumption made in ESI-MS affinity measurements is that the relative ion signals of free and bound species quantitatively reflect their rel...
Preprint
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The RMG-database for chemical property prediction is presented. The RMG-database consists of curated datasets and estimators for accurately predicting parameters necessary for constructing a wide variety of chemical kinetic mechanisms, including thermodynamics, kinetics, solvation effects, and transport properties. For thermochemistry prediction, t...
Article
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With the rising level of atmospheric CO2 worsening climate change, a promising global movement toward carbon neutrality is forming urgently. Sustainable CO2 management based on carbon capture and utilization has garnered considerable interest due to its critical role in resolving emission‐control and energy‐supply challenges. Here we present a comp...
Experiment Findings
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Use Factsage, and DWSim in an innovative manner using fundamentals of thermochemistry.
Conference Paper
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The majority of atmospheric entry vehicles use heat shields made of thermal protection materials that ablate during the re-entry phase as a result of thermo-chemical processes caused by aerothermodynamic heating. Ablation of the protection material results in material consumption at the surface and surface topology changes of the heat shield. In th...
Article
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Historically, defects in semiconductors and ionic conductors have been studied using very different approaches. In the solid state ionics community, non-stoichiometry and defect thermochemistry are often probed directly through experiments. The dependency of defect concentrations on chemical conditions (typically oxygen pressure) are modeled using...
Conference Paper
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During atmospheric entry, capsules and space debris are exposed to a flow environment with complex fluid thermochemistry and gas-surface interactions (GSI) that may lead to mass loss and shape change. A promising approach for the numerical simulation of such challenging flows is the use of immersed boundary (IB) and adaptive mesh refinement (AMR) t...
Article
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Knowledge of the fusion enthalpy as a function of temperature is necessary when performing rigorous thermodynamic calculations involving crystal-liquid transition. The fusion enthalpy can be measured directly only at the melting point (Tm). Derivation of its temperature dependence according to Kirchhoff’s law of Thermochemistry requires measuring t...
Conference Paper
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View Video Presentation: https://doi.org/10.2514/6.2022-3276.vid During atmospheric entry, the flow environment around capsules or space debris is characterized by complex fluid thermochemistry and gas-surface interactions (GSI). Computational fluid dynamics (CFD) simulations of these conditions are crucial in the design process of such objects. A...
Article
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This study is very promising for providing a renewable enrgy (H2 gas fuel) under the elctro-chemical splitting of the wastwater (sewage water). This study has double bene-fits: hydrogen generation and contaminations removel. This study is carried out on sewage water, third stage treated, from Beni-Suef city, Egypt. Antimony tin oxide (ATO)/polyanil...
Article
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Influx of matter from impacting meteoroids and hydrothermal crater weathering are important factors modifying the rock and mineral inventory of young planets undergoing heavy bombardment. These processes may have influenced not only the geochemical environment of, e.g. , early Mars and other planets, but also the peculiar prebiotic chemistry on ear...
Article
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We refer to the fourth state of matter as plasma, indicating ionized, electrically quasi-neutral gas. Electrical discharge in a gas medium is a normal and easy way of turning the gas into plasma in a moderate pressure condition. The electron temperature, electron density, and gas temperature characterize a quality of plasma. Particularly in the dom...
Article
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Ernst Julius Cohen (1869-1944) was an outstanding Dutch chemist and historian of chemistry of the second half of the XIX century and the first half of the XX century. He contributed to the fields of polymorphism, thermochemistry, electrochemistry and piezochemistry. He also studied physical isomerism. His experimental studies on allotropy has been...
Article
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Spontaneous oxidation of compounds containing diverse X=Y moieties (e.g., sulfonamides, ketones, esters, sulfones) occurs readily in organic-solvent microdroplets. This surprising phenomenon is proposed to be driven by the generation of an intermediate species [M+H 2 O] +· : a covalent adduct of water radical cation (H 2 O +· ) with the reactant mo...
Article
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Acid-base molecular clusters are an important stage in atmospheric new particle formation. While such clusters are most likely multicomponent in nature, there are very few reports on clusters consisting of multiple acid molecules and multiple base molecules. By applying state-of-the-art quantum chemical methods, we herein study electrically neutral...
Conference Paper
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A elaboração de material didático é uma das alternativas para melhorar o ensino. As Sequências de Ensino-Aprendizagem (SEA) podem ser fortes aliadas na pesquisa, pois podem pesquisar tanto o ensino como a aprendizagem. Este trabalho apresenta a validação interna de uma SEA sobre Termoquímica baseada nas ideias de validação de Méheut e Artigue. Atra...
Conference Paper
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El presente trabajo analiza la influencia del pretratamiento con microondas (MW) en los productos de pirólisis rápida de Eucalyptus globulus (EG) y Pinus radiata (PR). Se utilizó micro-pirólisis acoplada a cromatografía de gases/espectrometría de masas (Py-GC/MS) para identificar los componentes resultantes de la descomposición termoquímica de las...
Article
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We examine the analytical theories of heat developed by Laplace, Poisson and Carnot, and the thermodynamic theories based on the energy conservation and the principle of the increase of entropy formulated by Clausius. We present an analysis of the approaches developed by Maxwell, Gibbs, Planck, Duhem, Nernst, and De Donder as well as the irreversib...
Article
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One of the fundamental challenges in reticular chemistry is the characterization of the complexity of the underlying molecular network, in which high complexity signifies low symmetry and high diversity. The entropy of a network is one such topological descriptor that serves to characterize the order/disorder structural complexity. In this paper, w...
Article
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Using two-dimensional (2D) thermal structure models and pseudo-2D chemical kinetics models, we explore how atmospheric temperatures and composition change as a function of altitude and longitude within the equatorial regions of close-in transiting Neptune-class exoplanets at different distances from their host stars. Our models predict that the day...
Article
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A bluff-body stabilised turbulent jet flame burning in a stratified mode of combustion for fuel-lean methane/air mixtures is investigated by a flame-resolved simulation. A tabulated chemistry approach based on premixed flamelet generated manifolds (PFGM) accounts for thermochemistry. The computations are performed for a grid-resolution of 100 µm, s...
Article
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Guided inquiry learning has improved scientific literacy skills in various studies. This fact, however, contradicts new findings from the 2015 PISA survey. The research aims to assess inquiry-based OE3C learning methodologies that incorporate local socioscientific issues (SSI) to improve students' scientific literacy. The research method used quant...
Article
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The antioxidative nature of chemicals is now routinely studied using computational quantum chemistry. Scientists are constantly proposing new approaches to investigate those methods, and the subject is evolving at a rapid pace. The goal of this review is to collect, consolidate, and present current trends in a clear, methodical, and reference-rich...
Article
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Here, we present an investigation of the thermochemistry of proton uptake in acetonitrile across three charge states of a polyoxovanadate-alkoxide (POV-alkoxide) cluster, [V6O7(OMe)12]n (n = 2-, 1-, and 0). The vanadium oxide assembly studied features bridging sites saturated by methoxide ligands, isolating protonation to terminal vanadyl moieties....
Chapter
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O transporte ferroviário é um processo que inclui a conversão de combustível em trabalho útil pela locomotiva quando esta puxa ou empurra a composição de vagões. Será visto a termoquímica dos combustíveis e os combustíveis alternativos para locomotivas.
Chapter
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Conceitos de termoquímica. Ar como oxidante. Combustíveis. Combustão. Entalpia. Lei de Hess. Entalpias de formação. Entalpia dos principais combustíveis. Cálculo do calor gerado pelos combustíveis. Equilíbrio químico. Poluentes atmosféricos. Composição de produtos de combustão.
Article
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To meet the well-known energy transition challenge, a rapid shift from fossil fuels to the broader exploitation of renewable energy sources is needed; solar energy represents the most abundant and readily available resource amongst the renewable energy sources. This vision paper aims at shedding light on the current knowledge and emerging pathways...
Article
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Measurements of multi-scalar field within a combustor are of particular interest for engine performance promotion and failure diagnosis. Due to the harsh operating conditions and extremely limited space, direct measurements of combustion state in a near-real conditioned engine combustor were rarely reported. Therefore, this paper reports spontaneou...
Article
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Sulfuric acid and ammonia are believed to account for a large fraction of new-particle formation in the atmosphere. However, it remains unclear how small clusters grow to larger sizes, eventually ending up as stable aerosol particles. Here we present the largest sulfuric acid-ammonia clusters studied to date using quantum chemical methods by calcul...
Article
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In chemoradiation therapy, dissociative electron attachment (DEA) may play an important role with respect to the efficiency of the radiosensitizers used. The rational tailoring of such radiosensitizers to be more susceptive to DEA may thus offer a path to increase their efficiency. Potentially, this may be achieved by tailoring rearrangement reacti...
Article
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RESUMO: Este trabalho mostra os resultados de uma validação interna e externa de uma sequência de ensino-aprendizagem (SEA) sobre o tema Termoquímica. A validação interna ocorreu por meio da comparação dos resultados do pré-teste com o pós-teste e análise de entrevistas, avaliando-se então, a eficácia da SEA. A validação externa ocorreu através da...
Article
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TiP 4 N 8 was obtained from the binary nitrides TiN and P 3 N 5 upon addition of NH 4 F as a mineralizer at 8 GPa and 1400 °C. An intricate interplay of disorder and polymorphism was elucidated by in situ temperature‐dependent single‐crystal X‐ray diffraction, STEM‐HAADF, and the investigation of annealed samples. This revealed two polymorphs, that...
Article
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The simulation of reactive flows is a very challenging task from the computational point of view, as in addition to taking into account all the complex aspects of fluid dynamics, it requires a detailed description of the chemical kinetics involved in the process. Thus, the use of strategies to reduce simulation time is essential. Among the existing...
Article
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Sludge is one of the main pollutants from sewage treatment and contains a high content of water and organic matter. The co-combustion of sludge and coal can bring about the energy conversion of sludge. However, the high moisture content in sludge and the inorganic pollutants generated by co-combustion have adverse effects on combustion and the envi...
Preprint
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For electrochemically driven solar fuel-forming reactions thermochemistry dictates that the rate of the reaction will scale linearly with the overpotential of the catalyst, and for a molecular catalyst, overpotential is related to the redox couple (or E½) of the molecule. Enhancements in catalytic rates therefore rely on optimization of kinet-ic fa...
Article
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Thermal stabilities of selected ternary phases of industrial interest in the Ag-Cu-S system have been studied by the calorimetric and electromotive force techniques. The ternary compounds Ag1.2Cu0.8S (mineral mackinstryite) and AgCuS (mineral stromeyerite) were equilibrated through high-temperature reaction of the pure Cu2S and Ag₂S in an inert atm...
Preprint
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Chemical reaction networks (CRNs) are powerful tools for obtaining mechanistic insight into complex reactive processes. However, they are limited in their applicability where reaction mechanisms are not well understood and products are unknown. Here we report new methods of CRN generation and analysis that overcome these limitations. By constructin...
Article
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High-level computational data for standard gas phase enthalpies of formation, entropies, and heat capacities are reported for 116 compounds of boron. A comparison of the results with extant experimental and...
Article
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This research aims to develop Higher Order Thinking Skill (HOTS)-based test instruments on thermochemistry in the form of a valid and reliable multiple-choice question. This research applied Research and Development (R&D) design by using the development model of Borg & Gall. The respondents of this research were 55 high school students which came f...
Preprint
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High-order simulations of supersonic combustion are presented to advance understanding of the complex chemically-reacting flow processes and identify unknown mechanisms of the high-speed combustion process. We have employed 11th-order accurate implicit large-eddy simulations in conjunction with thermochemistry models comprising 20 chemical reaction...
Preprint
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Chemical reaction networks (CRNs) are powerful tools for obtaining mechanistic insight into complex reactive processes. However, they are limited in their applicability where reaction mechanisms are unintuitive, and products are unknown. Here we report new methods of CRN generation and analysis that overcome these limitations. By constructing CRNs...
Preprint
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The re-regularized semilocal meta generalized gradient approximation (meta-GGA) exchange-correlation functional r2SCAN [J. W. Furness, A. D. Kaplan, J. Ning, J. P. Perdew, and J. Sun, J. Phys. Chem. Lett. 11, 8208–8215 (2020)] is used to create the three global hybrid functionals with varying admixtures of Hartree–Fock exact exchange (HFX). The res...