Energetic Reactions Research Articles

Drug Delivery Methods, Applications and A New Horizon of Conjugated Drugs

Diseases and drugs are an inevitable part of our lives. People use several techniques to make the drug efficient. Biological molecules are chiral molecules; such as proteins, sugar, fat, hormones etc. Most of the market available drugs are chiral drugs. It can be either isomer or in enantiomeric form. Pure enantiomers are hard to produce. Now molecular techniques are more efficient to deliver drugs in proper places. Every cellular mechanism is energy driven. Phosphorylation helps with energetic reactions. During epigenetic changes methylation and acetylation takes place. New cancer or Alzheimer’s drug target this acetylation or methylation sites. Peptides can be attached with drugs for better penetration in cells or for the stability. Polyarginine is an efficient amino acid that helps with penetration. Amino acid Arginine helps with cell penetration. Peptide drug attached with nano particle taking attention recently. Dendrimers (branched polymer), chitin, dextrose has used for drug delivery purposes. PEGylation helps the drug to get into the blood for long time. It is biodegradable. siRNA or miRNA is now widely used to silence genes. Hydrophilic double stranded siRNA is negatively charged, and it can be packaged with positively charged nano‐particles. Quantum dot technology is used very often in nanotechnology. Now it’s application has started for drug delivery purposes. Some plant viruses are ineffective in human, and it is a good cargo for drugs. DNA and in situ hybridization is an effective technique for target‐specific drugs. Nano particle like gold, mesoporous silica nanoparticles carry positive surface charge get attached with negatively charged DNA very tightly, and helps to deliver deep inside the cell. Novel metals are good molecular cargo. Chitosan is a polycationic polymer and dissolves easily in an acidic environment. It has capability to release drug slowly and that makes it a good vehicle for drug delivery. miRNA are microRNAs, people have started using those RNAs to silence disease‐specific genes. Quantum dots are gaining popularity due to its less toxicity, surfactant‐free attachment and target specific delivery. New emerging drug delivery method started using fullerene (C60) and its dendrimers. The carbon atoms of fullerene do not attach with surrounding carbon atoms; these characteristics make it a good vehicle for drugs. Carbon‐hydrogen (C‐H) bond breaks down much faster than carbon‐carbon (C‐C) bonds. This property holds the fullerene structure intact.Polyethyleneimine can be tagged with nucleic acid or nano particle. DNA wrapped with magnetic nano particles and several natural polymers are getting importance for efficient drug delivery purposes. RNA, peptidoglycan, carbohydrate, fullerene, hydrogel is some of the examples. Artificially synthesized peptides can be a good source of drug.Enzymes and metabolic biosynthetic pathway go through a reduced and oxidized state and carry cellular electricity. Various protein complex takes part in it. Quorum sensing and biofilm formation is related to microbial biomolecule secretion. Highly reduced state creates atomic oxygen which eventually perturbs protein stoichiometry and agglutination and electron transport.Support or Funding InformationFormer Funding and Institutional Affiliation ASU, NIH/NIDDK, BSU, BMC, Advanced Laboratory, DaryGold, DARPA.

Design and performance considerations for dual-sided microstructured semiconductor neutron detectors

Thin-film-coated solid-state thermal neutron detectors were replaced in recent decades with the Microstructured Semiconductor Neutron Detector (MSND) technology. The basic device structure of the MSND involves micro-sized trenches that are etched into a vertically-oriented pvn-junction diode that are backfilled with a neutron converting material. Neutrons absorbed within the converting material induce fission of the parent nucleus, producing a pair of energetic charged-particle reaction products that can be counted by the diode. The deep-etched microstructures of the MSND yield good neutron-absorption efficiency and reaction-product counting efficiency, resulting in a 6-10x improvement in intrinsic thermal-neutron detection efficiency over thin-film-coated devices. Performance of present-day MSNDs are reaching an efficiency plateau; streaming paths between the conversion-material backfilled trenches, allow a considerable fraction of neutrons to pass through the device undetected. Dual-Sided Microstructured Semiconductor Neutron Detectors (DS-MSNDs) have been developed that utilize a complementary second set of trenches on the back-side of the device to capture streaming neutrons. This work investigates several of the fundamental design structures that can be etched into the semiconductor material, including repeated front-side and back-side patterns and inverse microfeature patterns. Results from MCNP6 simulations of DS-MSNDs show that intrinsic thermal-neutron detection efficiencies are often double that of their MSND counterparts and greater than 80% intrinsic thermal-neutron detection efficiency is theoretically possible with a 1.5-mm thick device.

Lithiophilic V2O5 nanobelt arrays decorated 3D framework hosts for highly stable composite lithium metal anodes

The lithium metal anode has been considered to be an optimal anode material for high-energy-density battery system due to its ultrahigh specific capacity. However, the sharp dendrite growth and infinite volume expansion have significantly impeded its commercial application. Herein, we propose that V2O5 as the lithiophilic substance can be decorated onto 3D stable frameworks to fabricate dendrite-suppressed composite Li metal anodes via a molten Li infusion method. It is demonstrated that the energetic chemical reaction between V2O5 and molten Li together with the capillary effect based on the nanostructure of interconnected V2O5 nanobelt arrays contributes synergistically to the great Li affinity of the V2O5-Ni foam (V2O5-NF) host and facilitate the efficient and uniform intake of molten Li into the 3D framework. Benefitting from the homogeneous Li distribution in the framework, the decreased local current density of the electrode and the stable property of the host, dendrite-free Li stripping/plating behavior and alleviated volume fluctuation have been achieved for the Li-V2O5-NF composite anode. Compared with the bare Li anode, the as-obtained Li-V2O5-NF composite anode exhibits much stable stripping/plating profiles with low overpotential (~18 mV) for ultralong lifespan (1600 h) at a current density of 1 mA cm−2 in symmetric Li/Li cell. Furthermore, outstanding rate capability and long-term cycling performance (78.8% capacity retention after 500 cycles under 2 C) are obtained in full cells when coupled with Li4Ti5O12 (LTO) cathodes, indicating a promising potential for practical application. Moreover, this work demonstrates that using a new lithiophilic material, V2O5, should be an effective method to construct high stable 3D Li metal anode for Li metal battery.

Fibrous bimetallic silver palladium and ruthenium palladium nanocrystals exhibit an exceptionally high active catalytic process in acetone hydrogenation

Highly dynamic catalytic reaction requires synergetic process of active adsorption and desorption of reactants on the catalyst's surface. This can be measured from the product yield and the catalyst's lifetime during the catalysis process. In this study, we discovered that bimetallization of the well-known Pd catalyst with Ag or Ru atoms modifies its crystal growth orientation and catalytic properties, leading to the generation of large area (due to fibrous structure) and unusual surface physicochemical properties for a highly energetic catalytic reaction in a model of a catalytic reaction, that is, acetone hydrogenation to produce isopropanol. In typical process, the kinetic rate of the reaction can be up to as high as 5.5 × 10−2 and 6 × 10−3 for AgPd and RuPd nanocatalysts, respectively, which are equivalent to the turnover frequency as high as of 2.3 × 102 s−1 and 1.4 × 102 s−1 for AgPd and RuPd nanocatalysts, respectively. This performance is much higher than the pristine Pd nanocatalyst and other nanocatalysts reported recently. The synthesis and the mechanism of catalytic properties enhancement will be discussed.

Characterization of the Laser Surface Nitriding of Ti-6Al-4V Alloys in Nitric Acid Solution and Nitrogen Gas Atmosphere

Laser nitriding is a surface engineering technique that is being used on titanium alloys to improve their surface hardness and wear resistance. It is an attractive process because of its simplicity and the possibility of producing hard layers of substantial depth with minimum effect to the bulk of the material. The current study characterized and compared laser surface nitriding of Ti-6Al-4V alloys in a nitric acid solution and in a nitrogen gas atmosphere. The melt pool shape, microstructure, hardness, and cracking susceptibility of the nitride layers processed at various nitrogen concentrations were investigated over a wide range of processing variables. The results show that the hardness of the laser nitrided layer increases with increases in both the concentration of nitrogen and the energy density of the laser. The hardness levels and hardened areas were significantly different because nitrogen has a different diffusivity in the nitric acid solution compared to a nitrogen gas atmosphere. When nitriding in a nitrogen atmosphere, the more energetic thermal reaction and accelerated surface vaporization cause rougher nitrided surfaces. The laser surface nitrided in a nitric acid solution significantly enhanced the hardening efficiency and hardness level without process-induced cracks. The results of this study will be useful in process design for the laser nitriding of Ti-6Al-4V alloy, which significantly enhances the surface performance of laser-processed parts. Key words: laser surface nitriding, Ti-6Al-4V alloy, nitric acid, nitrogen, hardness, roughness

Alternative outlets for sustaining photosynthetic electron transport during dark-to-light transitions

Environmental stresses dramatically impact the balance between the production of photosynthetically derived energetic electrons and Calvin-Benson-Bassham cycle (CBBC) activity; an imbalance promotes accumulation of reactive oxygen species and causes cell damage. Hence, photosynthetic organisms have developed several strategies to route electrons toward alternative outlets that allow for storage or harmless dissipation of their energy. In this work, we explore the activities of three essential outlets associated with Chlamydomonas reinhardtii photosynthetic electron transport: (i) reduction of O2 to H2O through flavodiiron proteins (FLVs) and (ii) plastid terminal oxidases (PTOX) and (iii) the synthesis of starch. Real-time measurements of O2 exchange have demonstrated that FLVs immediately engage during dark-to-light transitions, allowing electron transport when the CBBC is not fully activated. Under these conditions, we quantified maximal FLV activity and its overall capacity to direct photosynthetic electrons toward O2 reduction. However, when starch synthesis is compromised, a greater proportion of the electrons is directed toward O2 reduction through both the FLVs and PTOX, suggesting an important role for starch synthesis in priming/regulating CBBC and electron transport. Moreover, partitioning energized electrons between sustainable (starch; energetic electrons are recaptured) and nonsustainable (H2O; energetic electrons are not recaptured) outlets is part of the energy management strategy of photosynthetic organisms that allows them to cope with the fluctuating conditions encountered in nature. Finally, unmasking the repertoire and control of such energetic reactions offers new directions for rational redesign and optimization of photosynthesis to satisfy global demands for food and other resources.

O sincretismo na arte sacra das Missões Jesuíticas dos guarani: Índio Santo e Santo Índio

As Missões Jesuíticas foram espaços coloniais muito peculiares, cuja interação entre os europeus e indígenas foram orientadas pela catequização e evangelização das comunidades, em um ambiente de ordem, trabalho e oração. A Companhia de Jesus, em sua tarefa missionária, levava consigo conceitos importantes de desenvolvimento, como a arquitetura, a escultura, a marcenaria e a música, o que proporcionou um rico cenário material no período do apogeu das Missões. Nesta sinergia entre o cristianismo católico apostólico e o imaginário guarani, a arte sacra desenvolvida durante os séculos XVII e XVIII nestes espaços encontra um significado diferenciado, pois dotada de enorme sincretismo e fusão de elementos locais – especialmente os fenotípicos, que ressignificaram a expressão estética até então vigente para a representação das imagens sagradas de Jesus, Maria e dos santos católicos. Importante salientar que as peças eram feitas pelos guarani, cujas técnicas de escultura, estatuária e policromia lhes foram ensinadas pelos padres jesuítas, de maneira que tais representações lhes aproximaram da nova religião que lhes fora transmitida. O período coincide com a Contrarreforma católica e com a ascensão do movimento Barroco na arte, a reação enérgica da Igreja à Reforma Protestante, que, além de multiplicar o número de fiéis ao redor do mundo, com a conversão – imposta ou aceita - de grande parte da América em territórios cristãos, ainda alterou de forma significativa os padrões estéticos da arte no novo continente em redefinição. Assim, do estudo destas formas de representação do sagrado por parte dos indígenas ditos ‘missioneiros’ resulta o presente artigo, versando sobre a representação sincrética na arte sacra das Missões.

Synergistic Effects of Imidazolium-Functionalization on fac-Mn(CO)3 Bipyridine Catalyst Platforms for Electrocatalytic Carbon Dioxide Reduction.

The electrocatalytic reduction of carbon dioxide (CO2) could be a powerful tool for generating chemical fuels and feedstock molecules relevant to the chemical industry. One of the major challenges for molecular catalysts remains the necessity of high overpotentials, which can be overcome by identifying novel routes that improve the energetic reaction trajectory of critical intermediates during catalysis. In this combined experimental and computational study, we show that imidazolium functionalization of molecular fac-Mn(CO)3 bipyridine complexes results in CO2 reduction at mild electrochemical potentials in the presence of H2O. Importantly, our studies suggest that imidazolium groups in the secondary coordination sphere promote the formation of a local hydration shell that facilitates the protonation of CO2 reduction intermediates. As such, we propose a synergistic relationship between the functionalized catalyst and H2O, which stands in contrast to other systems in which the presence of H2O frequently has detrimental effects on catalysis.

Ultrashort-pulse laser-induced breakdown spectroscopy for detecting airborne metals during energetic reactions.

Ultrashort-pulse laser-induced breakdown spectroscopy (LIBS), specifically using a femtosecond laser, has certain advantages over longer-pulse, nanosecond-duration lasers, in that they typically have kilohertz repetition rates and reduced background noise along with little-to-no laser-plasma interaction, all of which lead to a better chance of detecting LIBS signals from trace particles. In this work, femtosecond-LIBS is investigated for the detection of metallic particles in the hot flame zone of solid propellant strands burning in the atmosphere. The metallic particles doped into the solid propellants were aluminum (Al), copper, lead, lead stearate, and mercury chloride, which are all either typically found in energetic formulations as additives or impurities. Using an 80-fs-pulse-duration, amplified Ti:Sapphire laser operating at 1000 Hz, single-shot concentration measurement experiments were performed. The femtosecond-LIBS apparatus could detect all metallic additives, whereas a previous nanosecond-LIBS scheme with comparable conditions was able to detect only higher concentrations of Al. The single-shot concentration study, conducted with the Al-doped propellants, indicated that there is a linear relationship between the percentage of laser shots detecting a LIBS signal and the mass percentage of Al initially present in the strands. The present results illustrate the advantages of using a femtosecond laser over a nanosecond laser for LIBS detection during energetics material reactions.

A redox reaction model for self-heating and aging prediction of Al/CuO multilayers

Sputter-deposited Al/CuO multilayers capable of highly energetic reactions have been the subject of intense studies for tunable initiation and actuation. Designing high performance Al/CuO-based initiator devices definitively requires reliable prediction of their ignition and reaction kinetics including self-heating or ageing as a function of heating rate and environmental conditions. The paper proposes a heterogeneous reaction model integrating an ensemble of basic mechanisms (oxygen diffusion, structural transformations, polymorphic phase changes) that have been collected from recent experimental investigations. The reaction model assumes that the rate of reaction is limited by the transport of oxygen across the growing layer of Al2O3 separating Al and CuO. Importantly, we show that the model predicts reasonably all exotherms through a wide range of temperature (ambient – 1000°C), all resulting from a pure diffusion process as experimentally observed for such Al/CuO multilayers. The model shows how the temperature ramp affects the structure of the multilayer and especially the growth of alumina-based interfacial regions. It highlights the importance of the interfacial chemistry evolution such as the native mixture of AlxCuyOz transformation into a thin amorphous alumina, and the polymorphic phase transformation of this latter. The first one occurring at ∼350°C results in a loss of continuity of the interface leading to the accelerated redox reaction whereas the second one occurring between 500 and 600°C produces a denser barrier to oxygen diffusion leading to the stop of redox reaction. We finally use the model to simulate thermal annealing as usually performed in accelerated ageing experiments. We theoretically observe and experimentally validate that a two weeks exposure of the multilayers at 200°C starts degrading the multilayers thermal properties whereas when the temperature remains below 200°C, the material keeps its entire integrity.

Run-Away Energetic Reactions in the Exhaust of Deposition Reactors

A model is developed to simulate the processes that may cause run-away exothermic reactions in the downstream of typical deposition reactors used in semiconductor manufacturing. This process model takes into account various modes of mass and heat transport as well as chemical reactions and provides insight into the key mechanisms that trigger the uncontrolled energetic reactions and cause the formation of potentially damaging hotspots. Using the developed model, a parametric study was conducted to analyze the effects of various system and operating conditions. In particular, the effects of the gaseous reactants concentrations and incoming temperature, the extent of accumulation of deposits, and the gas flow rate, and the reactions activation energy and heat of reaction are analyzed and the location and time of hot spot formation for each case are determined. The results are useful in developing strategies for mitigating the occurrence of the damaging energetic events.

Covalent vaccination with Trypanosoma cruzi Tc24 induces catalytic antibody production.

Trypanosoma cruzi 24 (Tc24) is a recently described B-cell superantigen (BC-SAg) expressed by all developmental stages of T.cruzi, the causative agent of Chagas disease. BC-SAgs are immunoevasins that interfere with the catalytic response available to a subset of natural antibodies comprising the preimmune (innate) repertoire. Electrophilic modifications of BC-SAgs facilitate the formation of highly energetic covalent reactions favouring B-cell differentiation instead of B-cell downregulation. Therefore, the aim of this study was to convert the inhibitory signals delivered to B-cells with specificity for Tc24 into activating signals after conjugating electrophilic phosphonate groups to recombinant Tc24 (eTc24). Covalent immunization with eTc24 increased the binding affinity between eTc24 and naturally nucleophilic immunoglobulins with specificity for this BC-SAg. Flow cytometric analyses demonstrated that eTc24 but not Tc24 or other electrophilically modified control proteins bound Tc24-specific IgM+ B-cells covalently. In addition, immunization of mice with eTc24 adjuvanted with ISA720 induced the production of catalytic responses specific for Tc24 compared to the abrogation of this response in mice immunized with Tc24/ISA720. eTc24-immunized mice also produced IgMs that bound recombinant Tc24 compared to the binding observed for IgMs purified from non eTc24-immunized controls. These data suggest that eTc24 immunization overrides the immunosuppressive properties of this BC-SAg.

Polska niepodległość w poezji „nowochłopskiej” (Nikołaj Klujew i Siergiej Jesienin)

The achievement of independence by Poland was preceded by WWI. The Kingdom of Poland was subjected to games between empires, which, in turn, contributed to the dissolution of our country executed by Prussia, Austria and Russia. This situation triggered an energetic reaction from Nikolai Klyuev and Sergei Yesenin. Among their oeuvre we may find poems about Poland in which Slavophilistic and pan-Slavist views are visible. Analysis of these poems perfectly suits postcolonial discourse.

Silicon quantum dots for energetic material applications

In its history as an energetic material, porous silicon has demonstrated flame speeds in excess of 3 km s−1, tunable combustion behavior, and high energy output, which in theory makes it a very attractive energetic system. In practice, its application within the field is limited by porous silicon's typical substrate-adhered form and caustic chemical processing requirements that limit how and when porous silicon is made. In this work, we have relieved porous silicon of these constraints by creating reactive silicon quantum dots from free-standing porous silicon films. The resulting material is composed of crystalline silicon nanoparticles with diameters as small as 2 nm that retain the chemical properties of the original films including the SiH2 termination layer. The fabricated silicon particles were characterized using FTIR Spectroscopy, TEM, and EDS for determining the size and the chemical composition. For testing as an energetic material fuel, porous silicon was mixed with an oft used oxidizer, sodium perchlorate. During open-channel combustion tests, silicon quantum dots mixed with sodium perchlorate demonstrated flame speeds over 2.5 km s−1, while bomb calorimetry tests showed an average heat of combustion of 7.4 kJ g−1. These results demonstrate the ability to retain the porous silicon material properties that allow for highly energetic material reactions to occur, despite the additional processing steps to create silicon quantum dots. This opens the door for the use of porous silicon in the bulk of the energetic material application space, much of which was previously limited due to the substrate-attached nature of typical porous silicon.

Vegard's-law-like dependence of the activation energy of blistering on the x composition in hydrogenated a-SixGe1-x

Surface quality is a key issue in semiconductor structures for device applications. Typical surface defects are blisters. Here we investigate on the relationship between the activation energy of blistering and the composition x in hydrogenated amorphous a-SixGe1-x by employing layers deposited by Radio Frequency sputtering. To this aim the blistering activation energy was determined by means of Arrhenius plots in several samples with different compositions, including x = 0 and x = 1. Each sample was submitted to heat treatment up to the temperature where the onset of blistering was observed by change of the surface reflectivity. It is found that a linear dependence of the activation energy on x similar to the Vegard's law holds. The experimental result is supported by reaction kinetics modeling. It is suggested that the key step for the formation of blisters is the scission of the SiH and GeH bonds. The related energetic reaction leading to the formation of H2 molecules in a-SixGe1-x follows a linear law as a function of the x composition similarly to the activation energy.

Electrochemical detection of dihydronicotinamide adenine dinucleotide using Al2O3-GO nanocomposite modified electrode

NADH plays a vital role in the electron transfer processes between metabolites in the cellular energetic reactions. Therefore, there is a crucial need to develop analytical techniques for detecting NADH levels with the metabolism of glucose. In the present study, a nanocomposite of alumina (Al2O3) nanoparticles confined graphene oxide (GO) sheet acts as a modifier for carbon paste electrode (CPE) for a sensitive detection of NADH level in a mediator-less detection scheme. Our findings after optimization of experimental conditions reveal that, there is a remarkable enhancement in the direct electron transfer through the Al2O3-GO nanocomposite surface with high electrocatalytic activity towards NADH oxidation. Results show that, there is a linear increase in NADH detection from 30 µM to 330 µM, together with linear regression coefficient of 0.98 and LOD 4.5 µM. These results confirm that, the developed Al2O3-GO based CPE electrode is a promising electrode for real NADH level detection in practical enzymatic applicability.

Double-Layered Composite Methods Extrapolating to Complete Basis-Set Limit for the Systems Involving More than Ten Heavy Atoms: Application to the Reaction of Heptafluoroisobutyronitrile with Hydroxyl Radical.

Two versions of the double-layered composite methods, including the restricted open-shell model chemistry based on the complete basis set quadratic mode (DL-ROCBS-Q) and the extrapolated CBS limit of electronic energy on the basis of the coupled cluster with single, double, and noniterative triple excitations with the hierarchical sequence of the correlation-consistent basis sets (DL-RCCSD(T)/CBS), were developed to calculate the energetic reaction routes for the systems involving 13/14 heavy atoms with good balance between efficiency and accuracy. Both models have been employed to investigate the oxidation reactions of heptafluoroisobutyronitrile ((CF3)2CFCN) with hydroxyl radical. The (CF3)2CFCN + OH reaction is dominated by the C-O addition/elimination routes as bifurcated into trans- and cis-conformations. Although the formation of isocyanic acid or hydrogen fluoride is highly exothermic, the major nascent product was predicted to be the less exoergic cyanic acid. Preference of the product channels could be tuned by the single water molecule in the presence of the H2O-HO complex. The production of amide compound was found to be the most significant route accompanied by the OH regeneration. Moreover, the OH radical could be an efficient catalyst for the hydrolysis of (CF3)2CFCN. Implication of the current theoretical results in the chemistry of (CF3)2CFCN for both atmospheric sink and potential dielectric replacement gas was discussed.

Excited state properties of 2′-hydroxychalcone analogues functionalized with a diene moiety studied by steady state and laser flash photolysis

2′-Hydroxychalcone (HC) analogues 1 and 2 having a diene part tethering the phenyl and naphthyl chromophores, respectively, were prepared, and their photochemical and photophysical properties were studied. Fluorescence from these compounds was absent in solution and the solid state. Based on the results obtained upon steady state and laser flash photolyses, compound 2 was found to be substantially stable on photoirradiation without undergoing intersystem crossing to the triplet state whereas compounds 1 showed transient absorption due to the triplet tautomer. The deactivation processes in the excited states were discussed by considering energetic reaction diagrams for the corresponding tautomers and isomers.

Investigations of excited-state relaxation processes in 2′- hydroxychalcone analogues having pyrrole and indole moieties based on emission and transient absorption measurements

Abstract Excited-state relaxation processes of five types of 2′-hydroxychalcone (HC) analogues having naphthol, pyrrole and indole chromophores were studied based on emission and transient absorption measurements. Fluorescence with large Stokes-shifts was observed from these compounds in solution and the solid state, indicating occurrence of excited-state intramolecular hydrogen atom transfer (ESIHT) as observed for HC in solution. These fluorescent species, were, therefore, considered to be the corresponding tautomer (cis-keto form) in the excited singlet (S1) states formed via ESIHT. The fluorescence quantum yields were larger by the magnitude of one order than that of HC. Upon 400 nm laser pulsing in benzene solution of these HC analogues, no transient absorption spectra were obtained for the analogues having the phenolic moiety (Ph@Py and Ph@Ind) whereas rise and decay profiles of transient spectra were recorded independently of the amount of the dissolved oxygen for HC analogues substituted with the naphthol moiety (Np@Py, Np@Ind and Np@Np). On the analogy of the deactivation processes of HC, the obtained transient species were suggested to be the corresponding isomer of the tautomer (trans-keto form) in the ground state due to the isomerization of the excited state cis-keto form. The deactivation processes in the excited states of these compounds were discussed by considering energetic reaction diagrams for the tautomers and isomers. Replacement of the phenol moiety of HC with the naphthol was demonstrated to affect the excited state properties of the tautomer.

Combustion of aluminum nanoparticles and exfoliated 2D molybdenum trioxide composites

Exfoliated two-dimensional (2D) molybdenum trioxide (MoO3) of approximately 3-4 monolayers in thickness was produced from sonicating bulk MoO3 powder, and then mixed with 80 nm diameter Al nanoparticles to prepare nanoenergetic composites with high interfacial contacts between the fuel and oxidizer. Combustion measurements demonstrated peak pressures as high as 42.05 ± 1.86 MPa, pressurization rates up to 3.49 ± 0.31 MPa/µs, and linear combustion rates up to 1,730 ± 98.1 m/s, the highest values reported to date for Al/MoO3 composites. TGA/DSC measurements indicate energetic reactions between the Al and 2D MoO3 sheets occur prior to the melting temperature of Al. SEM and TEM analysis of the composites prior to combustion suggests high interfacial contact area between the Al and MoO3. After reaction, we observe that the 2D MoO3 sheets are converted to extended alumina flakes during reaction in a process attributed to Al adsorption and diffusion processes. These alumina features act as a physical barrier against Al NP sintering while also provide separation for reaction gases to flow and preheat unreacted materials.