Thermal stability and compatibility of ammonium nitrate explosives on a small and large scale

1992 ◽  
Vol 212 ◽  
pp. 77-85 ◽  
Author(s):  
Jimmie C. Oxiey ◽  
Surender M. Kaushik ◽  
Nancy S. Gilson
Author(s):  
J. Liu ◽  
N. D. Theodore ◽  
D. Adams ◽  
S. Russell ◽  
T. L. Alford ◽  
...  

Copper-based metallization has recently attracted extensive research because of its potential application in ultra-large-scale integration (ULSI) of semiconductor devices. The feasibility of copper metallization is, however, limited due to its thermal stability issues. In order to utilize copper in metallization systems diffusion barriers such as titanium nitride and other refractory materials, have been employed to enhance the thermal stability of copper. Titanium nitride layers can be formed by annealing Cu(Ti) alloy film evaporated on thermally grown SiO2 substrates in an ammonia ambient. We report here the microstructural evolution of Cu(Ti)/SiO2 layers during annealing in NH3 flowing ambient.The Cu(Ti) films used in this experiment were prepared by electron beam evaporation onto thermally grown SiO2 substrates. The nominal composition of the Cu(Ti) alloy was Cu73Ti27. Thermal treatments were conducted in NH3 flowing ambient for 30 minutes at temperatures ranging from 450°C to 650°C. Cross-section TEM specimens were prepared by the standard procedure.


Author(s):  
Konstantin G. Gorbovskiy ◽  
Alena S. Ryzhova ◽  
Andrey M. Norov ◽  
Denis A. Pagaleshkin ◽  
Valentina N. Kalinina ◽  
...  

Complex mineral ammonium nitrate-based fertilizers are complex multicomponent salt systems possessing low thermal stability and prone to self-sustaining decomposition. This leads to the need to increase the requirements for fire and explosion safety in their manufacture, storage and transportation, caused by the fact that ammonium nitrate is a solid oxidant able to support a combustion, and its heating in confined space can lead to detonation. Components that make up such fertilizers can both reduce (phosphates and ammonium sulfate) and accelerate (chlorine compounds) decomposition of ammonium nitrate. Thus, the thermal stability of fertilizers based on ammonium nitrate largely depends on the ratio of the components that make up its composition or formed as a result of the chemical reaction. The simplest way to reduce the content of ammonium nitrate and increase the thermal stability of fertilizer without changing the content of essential nutrients is to increase the degree of phosphoric acid ammoniation. In this paper, the phase composition change of grade 22:11:11 nitrogen-phosphorus-potassium fertilizer obtained with different ammoniation degree in the process of thermal decomposition was studied by X-ray phase analysis. To obtain this fertilizer, wet-process phosphoric acid obtained sulfuric acid attack of the Khibin apatite concentrate by a hemihydrate method is used. It is shown that an increase in the ammoniation degree has a significant effect on the exothermic decomposition of ammonium nitrate and the amount of material that is released into the gas phase. The phases formed at each stage of the decomposition are determined.Forcitation:Gorbovskiy K.G., Ryzhova A.S., Norov A.M., Pagaleshkin D.A., Kalinina V.N., Mikhaylichenko A.I. Study of thermal decomposition products of nitrogen-phosphorus-potassium fertilizers based on ammonium nitrate by X-ray diffractuon. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 1. P. 72-77


Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1947
Author(s):  
Cunzhen Geng ◽  
Zhihui Zhao ◽  
Zhixin Xue ◽  
Peilong Xu ◽  
Yanzhi Xia

Cellulose, as one of the most abundant natural biopolymers, has been widely used in textile industry. However, owing to its drawbacks of flammability and ignitability, the large-scale commercial application of neat cellulose is limited. This study investigated some TEMPO-oxidized cellulose (TOC) which was prepared by selective TEMPO-mediated oxidation and ion exchange. The prepared TOC was characterized by Fourier transform infrared (FT-IR) spectroscopy and solid-state 13C-nuclear magnetic resonance (13C-NMR) spectroscopy. The thermal stability and combustion performance of TOC were investigated by thermogravimetry analysis (TG), microscale combustion calorimetry (MCC) and limiting oxygen index (LOI). The results demonstrated that the thermal stability of TOC was less than that of the pristine material cellulose, but the peak of heat release rate (pHHR) and the total heat release (THR) of all TOC were significantly reduced. Additionally, the LOI values of all TOC products were much higher 25%. In summary, the above results indicated that the modified cellulose with carboxyl groups and metal ions by selective oxidation and ion exchange endows efficient flame retardancy.


Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 1002 ◽  
Author(s):  
Chunmeng Xu ◽  
Lingjun Tang ◽  
Youxiang Liang ◽  
Song Jiao ◽  
Huimin Yu ◽  
...  

For large-scale bioproduction, thermal stability is a crucial property for most industrial enzymes. A new method to improve both the thermal stability and activity of enzymes is of great significance. In this work, the novel chaperones RrGroEL and RrGroES from Rhodococcus ruber, a nontypical actinomycete with high organic solvent tolerance, were evaluated and applied for thermal stability and activity enhancement of a model enzyme, nitrilase. Two expression strategies, namely, fusion expression and co-expression, were compared in two different hosts, E. coli and R. ruber. In the E. coli host, fusion expression of nitrilase with either RrGroES or RrGroEL significantly enhanced nitrilase thermal stability (4.8-fold and 10.6-fold, respectively) but at the expense of enzyme activity (32–47% reduction). The co-expression strategy was applied in R. ruber via either a plasmid-only or genome-plus-plasmid method. Through integration of the nitrilase gene into the R. ruber genome at the site of nitrile hydratase (NHase) gene via CRISPR/Cas9 technology and overexpression of RrGroES or RrGroEL with a plasmid, the engineered strains R. ruber TH3 dNHase::RrNit (pNV18.1-Pami-RrNit-Pami-RrGroES) and TH3 dNHase::RrNit (pNV18.1-Pami-RrNit-Pami-RrGroEL) were constructed and showed remarkably enhanced nitrilase activity and thermal stability. In particular, the RrGroEL and nitrilase co-expressing mutant showed the best performance, with nitrilase activity and thermal stability 1.3- and 8.4-fold greater than that of the control TH3 (pNV18.1-Pami-RrNit), respectively. These findings are of great value for production of diverse chemicals using free bacterial cells as biocatalysts.


2010 ◽  
Vol 1256 ◽  
Author(s):  
Girija Shankar Chaubey ◽  
Yuan Yao ◽  
Julien Pierre Amelie Makongo Mangan ◽  
Pranati Sahoo ◽  
Pierre F. P. Poudeu ◽  
...  

AbstractA simple method is reported for the synthesis of monodispersed HfO2 nanoparticles by the ammonia catalyzed hydrolysis and condensation of hafnium (IV) tert-butoxide in the presence of surfactants at room temperature. Transmission electron microscopy shows faceted nanoparticles with an average diameter of 3-4 nm. As-synthesized nanoparticles are amorphous in nature and crystallize upon moderate heat treatment. The HfO2 nanoparticles have a narrow size distribution, large specific surface area and good thermal stability. Specific surface area was about 239 m2/g on as-prepared nanoparticle samples while those annealed at 500 °C have specific surface area of 221 m2/g indicating that there was no significant increase in particle size. This result was further confirmed by TEM images of nanoparticles annealed at 300 °C and 500 °C. X-ray diffraction studies of the crystallized nanoparticles revealed that HfO2 nanoparticles were monoclinic in structure. The synthetic procedure used in this work can be readily modified for large scale production of monodispersed HfO2 nanoparticles.


2020 ◽  
Author(s):  
Gemma Torres Sallan ◽  
Eduard Borras ◽  
Martí Aliaguilla ◽  
Daniele Molognoni ◽  
Sonia Sanchis ◽  
...  

<p>Domestic wastewater (WW) is an important carrier of nutrients usually wasted away by current centralised sewage treatment plants. The Run4Life project proposes an alternative strategy for increasing circularity of WW treatment systems and improving nutrient recovery rates and material qualities. This is based on a decentralised treatment of segregated black water (BW), kitchen waste and grey water combining existing and innovative technologies.</p><p>Run4Life is currently improving innovative nutrient recovery technologies, these being: (i) an ultra-low flush vacuum toilet, which uses around 0.5L/flush, thus less water than conventional vacuum toilets, allowing concentration of BW compared to conventional toilets and vacuum toilets. (ii) Bio-electrochemical systems for nitrogen recovery, which recovers up to 12.8 g/m<sup>2</sup>*d of Nitrogen present in blackwater as liquid fertilizer (ammonium nitrate) iii) (Hyper-)thermophilic anaerobic digestion, which aims to recover the phosphorous and nitrogen in the hygienised effluent in a one-step treatment and ready for use as fertilisers.  </p><p>Nutrient recycling technologies from domestic WW are demonstrated at large scale in four demonstration sites where decentralised WW treatment systems are implemented: Ghent (Belgium, 430 houses), Helsingborg (Sweden, 320 apartments), Sneek (The Netherlands, 32 houses), and Vigo (Spain, 1 office building). This will result in solid and liquid NPK fertilizers being recovered in the form of struvite, ammonium nitrate, calcium phosphate, organic fertilizers and reclaimed water.</p><p>The environmental, economic and societal impact of the obtained fertilizers is being tested by means of ecotoxicology tests, pot experiments, field trials, and by a selection of key performance indicators based on European, national and regional legislation present in the four different countries. Life cycle assessments are being performed for each technology and demonstration site, and active measures such as knowledge brokerage activities are being developed as an engagement strategy to advocate the institutional, legal and social acceptance of the Run4Life nutrient recovery technologies and fertilizers produced.  In addition, new business models which can benefit from the Run4Life project are currently being assessed.</p><p>It is expected that, by the end of the project, more than 90% of the water will be reused, and that nutrient recovery rates will achieve 100%.</p>


ScienceRise ◽  
2020 ◽  
pp. 6-12
Author(s):  
Olena Han ◽  
Viktor Boiko ◽  
Viktor Kravets ◽  
Anatolii Han

Significant growth rates of construction require large areas prepared in advance. Given the complexity and large scale of construction on subsidence soils, an important issue remains their compaction. On the article, on the parameters of the explosion momentum of TNT-free explosive compositions based on ammonium nitrate (AN) and after ultrasonic treatment of ammonium nitrate were analytically investigated, and their comparison with ammonite №6 and igdanite was also compared. The principles of explosive pulse control by regulating the content and density of explosives due to ultrasonic radiation and foaming of low-density explosive mixtures have been developed and substantiated. Set the minimum value of the peak pressure at the interface "detonation product - environment" from time for foamed explosives after treatment with ultrasonic radiation. The object of research: Reclamation works and construction. Management of compaction of subsidence and flooded soils by directed action of explosive systems. Investigated problem: Taking into account that the method of compaction of subsiding loess soils with the energy of explosion is used in built-up areas, of particular importance is the control of the explosive pulse through the regulation of the content and density of explosives by ultrasonic radiation and foaming of low-density explosive mixtures this is done to ensure the required degree of compaction of the subsidence of the soil mass and to reduce the harmful seismic impact on the surrounding structures. The main scientific results: The dependence of the duration of the explosive pulse growth on the charge radius for different types of low-density explosives has been established, which indicates that the longest growth time of the explosive pulse is observed for charges based on foamed explosives, both conventional and ultrasonic treated. The dependences of the degree of soil compaction during the explosion of overhead charges of different types of explosives in the polymer housing on the specific costs of explosives are obtained. The research results allow to develop technological methods of controlling the parameters of the explosive pulse by using explosive density, which provides the opportunity to increase the efficiency of explosive energy to maintain the required degree of compaction of subsidence loess soils to a certain depth while seismic protection. The area of practical use of the research results: the use of this type of compaction of unstable soil is possible in the construction industry, in the mining industry and in the military. Innovative technological product: the methods of compaction of unstable soil with the energy of the explosion work when changing the parameters of the pulse, which will minimize the loss of energy in the blasting zone and increase the range of a single charge. Scope of the innovative technological product: the application of this method is possible: for compaction of unstable soil before construction, for soil compaction of runways at field airfields, for demining.


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