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• Author or Editor: R. Hu
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## Estimation of the critical temperature of thermal explosion for azido-acetic-acid-2-(2-azido-acetoxy)-ethylester using non-isothermal DSC

Journal of Thermal Analysis and Calorimetry
Authors:
H. Gao
,
F. Zhao
,
R. Hu
,
H. Zhao
, and
H. Zhang

## Abstract

A method for estimating the critical temperatures (T b) of thermal explosion for energetic materials is derived from Semenov’s thermal explosion theory and the non-isothermal kinetic equation dα/dt=A 0 T B f(α)e−E/RT using reasonable hypotheses. The final formula of calculating the value of T b is
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\left( {\frac{B} {{T_b }} + \frac{E} {{RT_b^2 }}} \right)$$ \end{document}
(T bT e0=1. The data needed for the method, E and T e0, can be obtained from analyses of the non-isothermal DSC curves. When B=0.5 the critical temperature (T b) of thermal explosion of azido-acetic-acid-2-(2-azido-acetoxy)-ethylester (EGBAA) is determined as 475.65 K.
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## Thermal Decomposition Characteristics of 1,7-Diazido-2,4,6-trinitrazaheptane and its Application in Propellants

Journal of Thermal Analysis and Calorimetry
Authors:
Z. Dang
,
F. Zhao
,
S. Li
,
C. Yin
, and
R. Hu

## Abstract

The thermal decomposition characteristics of1,7-diazido-2,4,6-trinitrazaheptane (DATH) and multi-component systems containing DATH were studied by using DSC, TG and DTG techniques. Three –NO2 groups in the DATH molecule break away first from the main chain when DATH is heated up to 200C. Following this process, the azido groups and the residual molecule decompose rapidly to release a great deal of heat within a short time. In the multi-component systems, DATH undergoes a strong interaction with the binder of the double-base propellant and a weak interaction with RDX. The burning rates of the two propellants were determined by using a Crawford bomb. The results showed that the burning rate rises by about 19–66% when 23.5%DATH is substituted for RDX in a minimum smoke propellant. Meanwhile, the N2 level in the combustion gases is enhanced, which is valuable for a reduction of the signal level of the solid propellant.

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## Thermochemistry of the complexes of chromium nitrate with l-a-amino acids

Journal of Thermal Analysis and Calorimetry
Authors:
S. Chen
,
X. Yang
,
Sh. Gao
,
R. Hu
, and
Q. Shi

## Abstract

The solid complexes of Cr(NO3)3 with L-α-amino acids (AA=Val, Leu, Thr, Arg, Phe and Try) have been prepared in 95% alcoholic, the compositions of which were identified as the general formula Cr(AA)2(NO3)32H2O by elemental and chemical analyses. The bonding characteristics of the title complexes were characterized by IR, indicating that nitrogen and oxygen atoms in the ligands coordinated to Cr3+ in a bidentate fashion. With the aid of TG-DTG and IR techniques, the complexes were subjected to thermal decomposition in an atmosphere of oxygen, presuming that the decompositions of the complexes consist of two steps and the complexes were decomposed into chromium hemitrioxide after undergoing dehydration and skeleton splitting of the complexes. The constant volume energies of combustion of the complexes were determined by a RBC-P type rotating-bomb calorimeter. According to Hess's law, the standard enthalpies of formation of the complexes were calculated as (-1831.404.40), (-2542.036.13), (-1723.813.99), (-2224.313.02), (-2911.616.53) and (-659.327.42) kJ mol-1, respectively.

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## Thermochemistry of the complexes of some microelements and histidine

Journal of Thermal Analysis and Calorimetry
Authors:
S. Chen
,
Sh Gao
,
X. Yang
,
R. Hu
, and
Q. Shi

## Abstract

Solid complexes of M(His)2Cl2 nH2O (M=Mn, Co, Ni, Cu) of MnCl26H2O, CoCl26H2O, NiCl26H2O, CuCl22H2O and L-α-histidine (His) have been prepared in 95% ethanol solution and characterized by elemental analyses, chemical analyses, IR and TG-DTG. The constant-volume combustion energies of the complexes have been determined by a rotating-bomb calorimeter. And the standard enthalpies of formation of the complexes have been calculated as well.

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## Thermal Behaviour of RE(His)(NO3)3⋅H2O

Journal of Thermal Analysis and Calorimetry
Authors:
M. Ji
,
J. Liu
,
S. Gao
,
R. Hu
, and
Q. Shi

## Abstract

The thermal decomposition behaviour of the complexes of rare earth metals with histidine: RE(His)(NO3)3 H2O (RE=La—Nd, Sm—Lu and Y; His=histidine) was investigated by means of TG-DTG techniques. The results indicated that the thermal decomposition processes of the complexes can be divided into three steps. The first step is the loss of crystal water molecules or part of the histidine molecules from the complexes. The second step is the formation of alkaline salts or mixtures of nitrates with alkaline salts after the histidine has been completely lost from the complexes. The third step is the formation of oxides or mixtures of oxides with alkaline salts. The results relating to the three steps indicate that the stabilities of the complexes increase from La to Lu.

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## Effect of high temperatures on the efficiency of sub-critical CO2 cycle

Pollack Periodica
Authors:
Aram Mohammed Ahmed
and
Attila R. Imre

## Abstract

Thermodynamic efficiency is a crucial factor of a power cycle. Most of the studies indicated that efficiency increases with increasing heat source temperature, regardless of heat source type. Although this assumption generally is right, when the heat source temperature is close to the critical temperature, increasing the heat source temperature can decrease efficiency. Therefore, in some cases, the increase in the source temperature, like using improved or more collectors for a solar heat source can have a double negative effect by decreasing efficiency while increasing the installation costs. In this paper, a comparison of the CO2 subcritical cycle and the Trilateral Flash Cycle will be presented to show the potential negative effect of heat source temperature increase.

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## Thermal behavior and thermal safety on 3,3-dinitroazetidinium salt of perchloric acid

Journal of Thermal Analysis and Calorimetry
Authors:
H. X. Ma
,
B. Yan
,
Y. H. Ren
,
Y. Hu
,
Y. L. Guan
,
F. Q. Zhao
,
J. R. Song
, and
R. Z. Hu

## Abstract

3,3-Dinitroazetidinium (DNAZ) salt of perchloric acid (DNAZ·HClO4) was prepared, it was characterized by the elemental analysis, IR, NMR, and a X-ray diffractometer. The thermal behavior and decomposition reaction kinetics of DNAZ·HClO4 were investigated under a non-isothermal condition by DSC and TG/DTG techniques. The results show that the thermal decomposition process of DNAZ·HClO4 has two mass loss stages. The kinetic model function in differential form, the value of apparent activation energy (E a) and pre-exponential factor (A) of the exothermic decomposition reaction of DNAZ·HClO4 are f(α) = (1 − α)−1/2, 156.47 kJ mol−1, and 1015.12 s−1, respectively. The critical temperature of thermal explosion is 188.5 °C. The values of ΔS , ΔH , and ΔG of this reaction are 42.26 J mol−1 K−1, 154.44 kJ mol−1, and 135.42 kJ mol−1, respectively. The specific heat capacity of DNAZ·HClO4 was determined with a continuous C p mode of microcalorimeter. Using the relationship between C p and T and the thermal decomposition parameters, the time of the thermal decomposition from initiation to thermal explosion (adiabatic time-to-explosion) was evaluated as 14.2 s.

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## Massive Goitre (Struma Parenchymatosa) in Geese

Acta Veterinaria Hungarica
Authors:
Éva Ivanics
,
P. Rudas
,
G. Sályi
, and
R. Glávits

In a goose flock consisting of 2300 birds of 6 months of age severe goitre was diagnosed. To the best of our knowledge this is the first report of naturally occurring goitre in geese, which is not related to the feeding of rapeseed meal. The major pathological findings included retarded growth and plumage development, significantly (300%) increased relative thyroid weight, fat accumulation in the mesenteric and abdominal region, and lipid infiltration of liver and kidney cells. Subsequent hormone analysis showed undetectable thyroxine (T4) levels and a dramatic drop in triiodothyronine (T3) plasma levels of the diseased geese. Thy- roidal histology displayed the typical signs of struma parenchymatosa. In order to get more information about the possible causes of the goitre, 10 geese from the affected farm were transferred into the laboratories of the Central Veterinary Institute. The geese were allotted into two groups. Group I received iodine supplementation for 55 days, while the other group served as sick control (Group S). Iodine treatment caused a dramatic improvement in the birds clinical condition except in plumage growth in Group I, while the clinical and main pathological signs of goitre remained unchanged or worsened in the untreated Group S. Contrary to this, the serum levels of thyroid hormones and responsiveness to thyrotropin releasing hormone (TRH) improved not only in Group I but also in Group S. Almost euthyroid biochemical parameters were found after 55 days of iodine treatment in Group I and, surprisingly, a considerable improvement (especially in serum T3 levels) occurred also in Group S. These findings confirm the diagnosis of goitre but also call attention to the fact that iodine deficiency was not the only factor eliciting the disorder. The underlying possible goitrogenic substance could not be traced down.

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## Pathogenicity of a bovine viral diarrhoea virus strain in pregnant sows: Short communication

Acta Veterinaria Hungarica
Authors:
G. Kulcsár
,
P. Soós
,
L. Kucsera
,
R. Glávits
, and
V. Pálfi

The biological properties of bovine viral diarrhoea virus (BVDV) strain Oregon C24V were studied after intranasal and subcutaneous infection of pregnant sows. This virus strain is widely used in Hungary for immunising cattle against bovine viral diarrhoea (BVD). Based upon the results of the clinical, gross pathological, histopathological and virological examinations it can be established that the given strain caused asymptomatic infection and serological conversion in sows that were in the second third of gestation. The virus caused clinically apparent disease in some of the piglets born at term, which indicates that it had crossed the placenta. More than half (57%) of the live-born piglets died within 60 days of birth. The sows and their progeny did not shed the virus. BVDV infection has great differential diagnostic importance in pigs, as classical swine fever (CSF) virus strains of reduced virulence cause similar clinical symptoms and gross and histopathological changes.

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## Addiciones y correcciones a la monografía rubiáceas de cuba

Acta Botanica Hungarica
Authors:
A. L. Borhidi
,
M. Fernández Zequeira
, and
R. Oviedo-Prieto

An important molecular-phylogenetic monography appeared about the Chiococceae tribe of the Caribbean region by Paudyal et al. (2018) proposing several new taxonomic modifying decisions concerning also to the monographic treatment of the recently (2017) published Rubiáceas de Cuba, as the confirmation and extension of the genus Solenandra revalidated by Borhidi (2002) and the separation of the new endemic Cuban genus Ramonadoxa Paudyal and Delprete from Chiococca. The molecular-phylogenetic studies did not verify the separation of Ceuthocarpus Aiello from Schmidtottia Urb. neither Phyllacanthus Hook. f. as independent genus from Catesbaea L.

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