Thermal Decomposition of Energetic Materials 26. Simultaneous Temperature Measurements of the Condensed Phase and Rapid-Scan FT-IR Spectroscopy of the Gas Phase at High Heating Rates

1987 ◽  
Vol 41 (7) ◽  
pp. 1147-1151 ◽  
Author(s):  
J. T. Cronin ◽  
T. B. Brill
Keyword(s):  
Real Time ◽  
Condensed Phase ◽  
Energetic Materials ◽  
Buffer Gas ◽  
Heating Rates ◽  
Decomposition Products ◽  
Gaseous Products ◽  
Rapid Scan ◽  
Ft Ir ◽  
Better Than

Rapid-scan infrared spectroscopy (RSFT-IR) with better than 100-ms temporal resolution has been used to quantify the gas decomposition products of energetic materials in real time at various heating rates up to 800°C/s and under buffer gas pressures of 1 to 1000 psi. A new method is described that permits simultaneous real-time recording of the temperature of the condensed phase and of the IR spectra of the gaseous products under the above conditions. Endothermic and exothermic events in the condensed phase can now be correlated with the evolved gases under conditions approaching those of combustion. The design and procedure for using the cell are given and are applied to the thermolysis of 1,7-diazido-2,4,6-trinitro-2,4,6-triazaheptane (DATH) and pentaery-thrityltetrammonium nitrate (PTTN).

Thermal Decomposition of Energetic Materials 33: The Thermolysis Pathway of the Azidodinitromethyl Group

1989 ◽  
Vol 43 (4) ◽  
pp. 650-653 ◽  
Author(s):  
J. T. Cronin ◽  
T. B. Brill
Keyword(s):  
Thermal Decomposition ◽  
Energetic Materials ◽  
Functional Group ◽  
The Other ◽  
Nitrate Ester ◽  
Ir Studies ◽  
Rapid Scan ◽  
Gas Products ◽  
Ft Ir ◽  
Ar Gas

Rapid-scan FT-IR studies are reported for the thermal decomposition of R (CH2)3C(NO2)2N3 ( R = CH3OC(O)-, HO-, -OC(O)O-, and O2NO-) at a heating rate of 70°C/s or higher. The thermolysis is initiated by the -C(NO2)2N, group. At 15 psi Ar, a sharp exotherm occurs at about 180°C. Except when R = O2NO-, the gas products are NO2, N2 (inferred), and R(CH2)3CN, making the rapid thermal decomposition one of the most straightforward yet observed for an energetic functional group. At an Ar gas pressure of 500 psi, the products are altered only to the extent that partial oxidation of the organonitrile occurs. The exotherm remains at about 180°C but is greatly accentuated. When R = O2NO-, the thermolysis temperature profile is very similar to the other compounds, but an organonitrile is not detected. Instead, at 15 psi Ar, a mixture of gas products resulting from the reaction of NO, with the backbone is detected, indicating that the nitrate ester also reacts. At 500 psi Ar, the products and thermal profile of this compound are characteristic of an explosion.

COMBUSTION OF ENERGETIC MATERIALS GOVERNED BY REACTIONS IN THE CONDENSED PHASE

2010 ◽  
Vol 9 (2) ◽  
pp. 147-192 ◽  
Author(s):  
Valery P. Sinditskii ◽  
Viacheslav Yu. Egorshev ◽  
Valery V. Serushkin ◽  
Anton I. Levshenkov ◽  
Maxim V. Berezin ◽  
...  
Keyword(s):  
Condensed Phase ◽  
Energetic Materials

scholarly journals An Improved Multipath Mitigation Method and Its Application in Real-Time Bridge Deformation Monitoring

2021 ◽  
Vol 13 (12) ◽  
pp. 2259
Author(s):  
Ruicheng Zhang ◽  
Chengfa Gao ◽  
Qing Zhao ◽  
Zihan Peng ◽  
Rui Shang
Keyword(s):  
Real Time ◽  
Sampling Rate ◽  
Threshold Value ◽  
Deformation Monitoring ◽  
Success Rates ◽  
Multipath Mitigation ◽  
Mode Decomposition ◽  
Observation Noise ◽  
Original Observation ◽  
Better Than

A multipath is a major error source in bridge deformation monitoring and the key to achieving millimeter-level monitoring. Although the traditional MHM (multipath hemispherical map) algorithm can be applied to multipath mitigation in real-time scenarios, accuracy needs to be further improved due to the influence of observation noise and the multipath differences between different satellites. Aiming at the insufficiency of MHM in dealing with the adverse impact of observation noise, we proposed the MHM_V model, based on Variational Mode Decomposition (VMD) and the MHM algorithm. Utilizing the VMD algorithm to extract the multipath from single-difference (SD) residuals, and according to the principle of the closest elevation and azimuth, the original observation of carrier phase in the few days following the implementation are corrected to mitigate the influence of the multipath. The MHM_V model proposed in this paper is verified and compared with the traditional MHM algorithm by using the observed data of the Forth Road Bridge with a seven day and 10 s sampling rate. The results show that the correlation coefficient of the multipath on two adjacent days was increased by about 10% after residual denoising with the VMD algorithm; the standard deviations of residual error in the L1/L2 frequencies were improved by 37.8% and 40.7%, respectively, which were better than the scores of 26.1% and 31.0% for the MHM algorithm. Taking a ratio equal to three as the threshold value, the fixed success rates of ambiguity were 88.0% without multipath mitigation and 99.4% after mitigating the multipath with MHM_V. The MHM_V algorithm can effectively improve the success rate, reliability, and convergence rate of ambiguity resolution in a bridge multipath environment and perform better than the MHM algorithm.

scholarly journals Pyrolysis and Oxidation of PAN in Dry Air. Thermoanalytical Methods

1970 ◽  
Vol 17 (1) ◽  
pp. 38-42
Author(s):  
Anna BIEDUNKIEWICZ ◽  
Pawel FIGIEL ◽  
Marta SABARA
Keyword(s):  
Temperature Increase ◽  
Heating Rates ◽  
Linear Change ◽  
Dry Air ◽  
Isothermal Conditions ◽  
Gaseous Products ◽  
Heterogeneous Processes ◽  
Temperature Ranges ◽  
Higher Temperature ◽  
Kinetics Of

The results of investigations on pyrolysis and oxidation of pure polyacrylonitrile (PAN) and its mixture with N,N-dimethylformamide (DMF) under non-isothermal conditions at linear change of samples temperature in time are presented. In each case process proceeded in different way. During pyrolysis of pure PAN the material containing mainly the product after PAN cyclization was obtained, while pyrolysis of PAN+DMF mixture gave the product after cyclization and stabilization. Under conditions of measurements, in both temperature ranges, series of gaseous products were formed.For the PAN-DMF system measurements at different samples heating rates were performed. The obtained results were in accordance with the kinetics of heterogeneous processes theory. The process rates in stages increased along with the temperature increase, and TG, DTG and HF function curves were shifted into higher temperature range. This means that the process of pyrolysis and oxidation of PAN in dry air can be carried out in a controlled way.http://dx.doi.org/10.5755/j01.ms.17.1.246

Detection of individual atoms in helium buffer gas and observation of their real-time motion

1980 ◽  
Vol 5 (11) ◽  
pp. 459 ◽  
Author(s):  
C. L. Pan ◽  
J. V. Prodan ◽  
W. M. Fairbank ◽  
C. Y. She
Keyword(s):  
Real Time ◽  
Buffer Gas ◽  
Time Motion

scholarly journals Evaluation of IMERG Level-3 Products in Depicting the July to October Rainfall over Taiwan: Typhoon Versus Non-Typhoon

2021 ◽  
Vol 13 (4) ◽  
pp. 622
Author(s):  
Wan-Ru Huang ◽  
Pin-Yi Liu ◽  
Ya-Hui Chang ◽  
Cheng-An Lee
Keyword(s):  
Real Time ◽  
Tropical Rainfall Measuring Mission ◽  
Temporal Variations ◽  
Rain Gauge ◽  
Advantages And Disadvantages ◽  
Level 3 ◽  
Spatio Temporal ◽  
Typhoon Season ◽  
Early Late ◽  
Better Than

This study assesses the performance of satellite precipitation products (SPPs) from the latest version, V06B, Integrated Multi-satellitE Retrievals for Global Precipitation Mission (IMERG) Level-3 (including early, late, and final runs), in depicting the characteristics of typhoon season (July to October) rainfall over Taiwan within the period of 2000–2018. The early and late runs are near-real-time SPPs, while final run is post-real-time SPP adjusted by monthly rain gauge data. The latency of early, late, and final runs is approximately 4 h, 14 h, and 3.5 months, respectively, after the observation. Analyses focus on the seasonal mean, daily variation, and interannual variation of typhoon-related (TC) and non-typhoon-related (non-TC) rainfall. Using local rain-gauge observations as a reference for evaluation, our results show that all IMERG products capture the spatio-temporal variations of TC rainfall better than those of non-TC rainfall. Among SPPs, the final run performs better than the late run, which is slightly better than the early run for most of the features assessed for both TC and non-TC rainfall. Despite these differences, all IMERG products outperform the frequently used Tropical Rainfall Measuring Mission 3B42 v7 (TRMM7) for the illustration of the spatio-temporal characteristics of TC rainfall in Taiwan. In contrast, for the non-TC rainfall, the final run performs notably better relative to TRMM7, while the early and late runs showed only slight improvement. These findings highlight the advantages and disadvantages of using IMERG products for studying or monitoring typhoon season rainfall in Taiwan.

Maximum heating rates for producing undistorted glassy carbon ware determined by wedge-shaped samples

1996 ◽  
Vol 11 (9) ◽  
pp. 2368-2375 ◽  
Author(s):  
Hossein Maleki ◽  
Lawrence R. Holland ◽  
Gwyn M. Jenkins ◽  
R. L. Zimmerman ◽  
Wally Porter
Keyword(s):  
Heating Rate ◽  
Treatment Process ◽  
Gaseous Product ◽  
Pyrolysis Mass Spectrometry ◽  
Heating Rates ◽  
Gaseous Products ◽  
Volatile Products ◽  
Solid Bodies ◽  
Polymeric Carbon ◽  
Maximum Heating

Polymeric carbon artifacts are particularly difficult to make in thick section. Heating rate, temperature, and sample thickness determine the outcome of carbonization of resin leading to a glassy polymeric carbon ware. Using wedge-shaped samples, we found the maximum thickness for various heating rates during gelling (300 K–360 K), curing (360 K–400 K), postcuring (400 K–500 K), and precarbonization (500 K–875 K). Excessive heating rate causes failure. In postcuring the critical heating rate varies inversely as the fifth power of thickness; in precarbonization this varies inversely as the third power of thickness. From thermogravimetric evidence we attribute such failure to low rates of diffusion of gaseous products of reactions occurring within the solid during pyrolysis. Mass spectrometry shows the main gaseous product is water vapor; some carboniferous gases are also evolved during precarbonization. We discuss a diffusion model applicable to any heat-treatment process in which volatile products are removed from solid bodies.

Study on Modified Rapeseed Oil/Montmorillonite Nanocomposites

2010 ◽  
Vol 123-125 ◽  
pp. 1291-1294 ◽  
Author(s):  
Bin Lü ◽  
Jian Zhong Ma ◽  
Dang Ge Gao ◽  
Lei Hong
Keyword(s):  
Rapeseed Oil ◽  
Fourier Transforms ◽  
Raw Materials ◽  
Infrared Spectrometry ◽  
Emulsifying Properties ◽  
X Ray Diffraction ◽  
Layer Spacing ◽  
Transmission Electron ◽  
Ft Ir ◽  
Better Than

Modified rapeseed oil(MRO) was prepared by using rapeseed oil, ethylene diamine and acrylic acid as the raw materials. Modified rapeseed oil/montmorillonite(MRO/MMT) nanocomposite was prepared by using modified rapeseed oil and montmorillonite. The emulsifying properties of MRO and MRO/MMT were determined respectively. Fourier transforms infrared spectrometry (FT-IR) and Transmission Electron microscope (TEM) results showed that MRO/MMT was prepared successfully. X-ray diffraction (XRD) results showed that modified rapeseed oil could smoothly enter the interlayer of montmorillonite, and modified the montmorillonite; with an increase in the amount of montmorillonite, the layer spacing of montmorillonite in the MRO/MMT lower after the first increase. The results of emulsifying properties indicated that emulsifying properties of MRO/MMT was better than MRO.

A Comparison of FT-IR/PA and FT-IR/PBD Spectra of Powders

1986 ◽  
Vol 40 (5) ◽  
pp. 636-641 ◽  
Author(s):  
P. G. Varlashkin ◽  
M. J. D. Low ◽  
G. A. Parodi ◽  
C. Morterra
Keyword(s):  
Probe Beam ◽  
Beam Deflection ◽  
Signal To Noise ◽  
Absorption Bands ◽  
Ir Radiation ◽  
Laser Probe ◽  
Ft Ir ◽  
Better Than

FT-IR photoacoustic (PA) and also photothermal beam deflection (PBD) spectra were recorded with the same particulate samples (graphite, charcoal, aspirin, and silica) under the same conditions in order to compare the quality of the spectra obtainable with the two techniques. A PA cell fitted with windows for the PBD laser probe beam was used, and PA and PBD spectra of each sample were recorded at 8 cm−1 resolution at each of the four different interferometer scan velocities. Although the overall aspects of FT-IR/PA and FT-IR/PBD spectra are the same, the signal-to-noise ratios of PA spectra are appreciably better than those of PBD spectra because PBD detection is more prone to disturbance by vibration than is PA detection. Absorption bands appear at the same wavenumbers in PA and PBD spectra. However, the relative intensities of bands of PBD spectra depend on the absorptive properties of the powdered solids; with weak absorbers, some bands may not be detected at all. PAS can be used with all powders. PBDS is of little or no use for the examination of weakly absorbing powders unless they scatter IR radiation extensively.

Analysis of Noise for Rapid-Scan and Step-Scan Methods of FT-IR Difference Spectroscopy

2001 ◽  
Vol 55 (9) ◽  
pp. 1161-1165 ◽  
Author(s):  
Steven S. Andrews ◽  
Steven G. Boxer
Keyword(s):  
Difference Spectroscopy ◽  
Rapid Scan ◽  
Ft Ir
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