scholarly journals Effect of Mixture Concentration Inhomogeneity on Detonation Properties in Pressure Gain Combustors

2018 ◽  
Author(s):  
Domenic Santavicca
Keyword(s):  
Detonation Properties ◽  
Mixture Concentration ◽  
Concentration Inhomogeneity

Kinetic Adsorption of Humic Acids Mixture Obtained from Microalgae on Exfoliated Graphite Nanoplatelets

2018 ◽  
Vol 69 (1) ◽  
pp. 191-195
Author(s):  
Elena Radu ◽  
Elena Emilia Oprescu ◽  
Cristina Emanuela Enascuta ◽  
Catalina Calin ◽  
Rusandica Stoica ◽  
...  
Keyword(s):  
Humic Acid ◽  
Humic Acids ◽  
Alkali Treatment ◽  
Exfoliated Graphite ◽  
Acid Mixture ◽  
Acidic Ph ◽  
Graphite Nanoplatelets ◽  
Mixture Concentration ◽  
Ft Ir ◽  
Exfoliated Graphite Nanoplatelets

The dehydration of polysaccharides fraction in the presence of acid catalysts, is a chemical process in which results as secondary product humic matter. In our work, the humic acid mixture was for the first time based on our knowledge extracted from defatted microalgae biomass rich in polysaccharides by standard alkali treatment, followed by precipitation at acidic pH. The dried humic acid mixture has been characterized using infrared spectroscopic measurements (FT-IR). Exfoliated graphite nanoplatelets (xGnP) were used as new adsorbents for this type of humic acids mixture, their adsorption being investigated. The effect of several parameters such as: contact time, concentration of humic acid mixture, concentration of xGnP, temperature and pH of the solutions were studied. The process of adsorption took place with good results, in the following conditions: at a concentration of humic acid mixture of 18.6 mg L-1, an xGnP amount of 0.01 mg in 25 mL of solution, at a temperature of 25 �� and at acidic pH values, in aqueous solution.

scholarly journals Environmentally Relevant Mixture of Pesticides Affect Mobility and DNA Integrity of Early Life Stages of Rainbow Trout (Oncorhynchus mykiss)

Toxics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 174
Author(s):  
Shannon Weeks Santos ◽  
Jérôme Cachot ◽  
Bettie Cormier ◽  
Nicolas Mazzella ◽  
Pierre-Yves Gourves ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Protein Carbonyl ◽  
Swimming Activity ◽  
Mitochondrial Metabolism ◽  
Pesticide Mixture ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Mixture Concentration

The aim of this study was to analyze the impact of three concentrations of a pesticide mixture on the first development stages of rainbow trout (Oncorhynchus mykiss). The mixture was made up of three commonly used pesticides in viticulture: glyphosate (GLY), chlorpyrifos (CPF) and copper sulfate (Cu). Eyed stage embryos were exposed for 3 weeks to three concentrations of the pesticide mixture. Lethal and sub-lethal effects were assessed through a number of phenotypic and molecular endpoints including survival, hatching delay, hatching success, biometry, swimming activity, DNA damage (Comet assay), lipid peroxidation (TBARS), protein carbonyl content and gene expression. Ten target genes involved in antioxidant defenses, DNA repair, mitochondrial metabolism and apoptosis were analyzed using real-time RT-qPCR. No significant increase of mortality, half-hatch, growth defects, TBARS and protein carbonyl contents were observed whatever the pesticide mixture concentration. In contrast, DNA damage and swimming activity were significantly more elevated at the highest pesticide mixture concentration. Gene transcription was up-regulated for genes involved in detoxification (gst and mt1), DNA repair (ogg1), mitochondrial metabolism (cox1 and 12S), and cholinergic system (ache). This study highlighted the induction of adaptive molecular and behavioral responses of rainbow trout larvae when exposed to environmentally realistic concentrations of a mixture of pesticides.

scholarly journals Gas-phase detonation propagation in mixture composition gradients

2012 ◽  
Vol 370 (1960) ◽  
pp. 567-596 ◽  
Author(s):  
D. A. Kessler ◽  
V. N. Gamezo ◽  
E. S. Oran
Keyword(s):  
Activation Energy ◽  
Reaction Model ◽  
Single Step ◽  
Mixture Composition ◽  
Composition Gradient ◽  
Detonation Properties ◽  
High Activation ◽  
Zone Structure ◽  
Detonation Cell ◽  
High Activation Energy

The propagation of detonations through several fuel–air mixtures with spatially varying fuel concentrations is examined numerically. The detonations propagate through two-dimensional channels, inside of which the gradient of mixture composition is oriented normal to the direction of propagation. The simulations are performed using a two-component, single-step reaction model calibrated so that one-dimensional detonation properties of model low- and high-activation-energy mixtures are similar to those observed in a typical hydrocarbon–air mixture. In the low-activation-energy mixture, the reaction zone structure is complex, consisting of curved fuel-lean and fuel-rich detonations near the line of stoichiometry that transition to decoupled shocks and turbulent deflagrations near the channel walls where the mixture is extremely fuel-lean or fuel-rich. Reactants that are not consumed by the leading detonation combine downstream and burn in a diffusion flame. Detonation cells produced by the unstable reaction front vary in size across the channel, growing larger away from the line of stoichiometry. As the size of the channel decreases relative to the size of a detonation cell, the effect of the mixture composition gradient is lessened and cells of similar sizes form. In the high-activation-energy mixture, detonations propagate more slowly as the magnitude of the mixture composition gradient is increased and can be quenched in a large enough gradient.

High-performing and thermally stable energetic 3,7-diamino-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazole derivatives

2017 ◽  
Vol 5 (13) ◽  
pp. 6100-6105 ◽  
Author(s):  
Yongxing Tang ◽  
Chunlin He ◽  
Gregory H. Imler ◽  
Damon A. Parrish ◽  
Jean'ne M. Shreeve
Keyword(s):  
Detonation Properties ◽  
Thermally Stable ◽  
Triazole Derivatives ◽  
High Performing

A family of 3,7-diamino-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazole derivatives is reported and some show promising detonation properties.

Two energetic complexes incorporating 3,5-dinitrobenzoic acid and azole ligands: microwave-assisted synthesis, favorable detonation properties, insensitivity and effects on the thermal decomposition of RDX

2016 ◽  
Vol 40 (9) ◽  
pp. 7779-7786 ◽  
Author(s):  
Qi Yang ◽  
Jing Ge ◽  
Qibing Gong ◽  
Xiaxia Song ◽  
Jinwen Zhao ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Microwave Assisted Synthesis ◽  
Detonation Properties ◽  
Microwave Assisted ◽  
Green Propellants

The two energetic complexes reported may act as attractive candidates for green propellants.

Molecular design on a new family of azaoxaadamantane cage compounds as potential high-energy density compounds

2019 ◽  
Vol 97 (2) ◽  
pp. 86-93 ◽  
Author(s):  
Yong Pan ◽  
Weihua Zhu ◽  
Heming Xiao
Keyword(s):  
Thermal Stability ◽  
Density Functional ◽  
Parent Compound ◽  
High Energy ◽  
High Energy Density ◽  
Lower Sensitivity ◽  
Detonation Properties ◽  
Detonation Pressure ◽  
Cage Compounds ◽  
New Family

A new family of azaoxaadamantane cage compounds were firstly designed by introducing the oxygen atom into hexanitrohexaazaoxaadmantane (HNHAA) to replace the N–NO2 group. Their properties including heats of formation (HOFs), detonation properties, strain energies, thermal stability, and sensitivity were extensively studied by using density functional theory. All of the title compounds exhibit surprisingly high density (ρ > 2.01 g/cm3) and excellent detonation properties (detonation velocity (D) > 9.29 km/s and detonation pressure (P) > 40.80 GPa). In particular, B (4,8,9,10-tetraazadioxaadamantane) and C (6,8,9,10-tetraazadioxaadamantane) have a remarkably high D and P values (9.70 km/s and 44.45 GPa, respectively), which are higher than that of HNHAA or CL-20. All of the title compound have higher thermal stability and lower sensitivity (h50 > 19.58 cm) compared with the parent compound HNHAA. Three triazatrioxaadamantane cage compounds, D (6,8,9-triazatrioxaadamantane), E (6,8,10-triazatrioxaadamantane), and F (8,9,10-triazatrioxaadamantane), are expected to be relatively insensitive explosives. All of the title compounds exhibit a combination of high denotation properties, good thermal stability, and low insensitivity.

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