Coupling effect on the thermal hazard assessment of hazardous chemical materials via calorimetric technologies and simulation approaches

The coupling effect of heat absorption and release exists in the thermal decomposition of a few chemical materials.However,the impact of the above coupling on thermal hazard assessment is not considered in the literature studies.In this work,nitroguanidine(NQ)and 1,3,5-trinitro-1,3,5-triazine(RDX)are selected as representative materials to explore the influence of the coupling effect on the thermal hazard assessment of chemical materials.The linear heating experiments of NQ and RDX are carried out by a microcalorimeter and synchronous thermal analyser.The thermal decomposition curves are decoupled by advanced thermokinetics software.The thermal decomposition and kinetic parameters before and after decoupling are calculated.The results of TG experiment show that both NQ and RDX began to lose mass during the endothermic stage.The endothermic melting and exothermic decomposition of NQ and RDX are coupled within this stage.The coupling effect has different degrees of influence on its initial decomposition temperature and safety parameters.Compared with the parameters in the coupling state,the initial decomposition temperature and adiabatic induction period after decoupling decrease.The self-accelerating decomposition temperature increases,and internal thermal runaway time decreases.In the thermal hazard assessment of chemical materials with coupling effects,the calculated parameters after decoupling should be taken as an important safety index。

Some problerns in adsorption and calorimetric studies of the steps of catalytic processes

Principal side factors as well as technical and procedural peculiarities capable of distorting the results of measurements of adsorbed and desorbed amounts, of falsifying the nature of the processes proceeding in the systems under study, and of promoting artifacts in calorimetric and other studies of gas chemisorption on powders are considered. Modified techniques and procedures allowing the elimination of sources of side phenomena and artifacts and freeing traditional glass static adsorption apparatuses and experimental procedures from undesirable factors and peculiarities are proposed. Some available chemisorption and calorimetric data representing artifacts and also some data that are not artifacts but, due to imperfections of chemisorption techniques, show up as artifacts are presented and discussed. Several applications of the improved techniques and procedures to calorimetric and adsorption studies of the steps of catalytic processes proceeding on the basis of natural gas and of products of its processing are presented and discussed.

Calorimetric Determination of Enthalpy of Formation of Natural Gas Hydrates

This paper reports the measurements of enthalpies of natural gas hydrates in typical natural gas mixture containing methane, ethane, propane and iso-butane at pressure in the vicinity of 2000 kPa (300 psi) and 6900 kPa(1000psi). The measurements were made in a multi-cell differential scanning calorimeter using modified high pressure cells. The enthalpy of water and the enthalpy of dissociation of the gas hydrate were determined from the calorimeter response during slow temperature scanning at constant pressure. The amount of gas released from the dissociation of hydrate was determined from the pumped volume of the high pressure pump. The occupation ratio (mole ratio) of the water to gas and the enthalpy of hydrate formation are subject to uncertainty of 1.5%.The results show that the enthalpy of hydrate formation and the occupation ratio are essentially independent of pressure.

Calorimetric Measurements of CuAlNi Alloys

The martensitic transformation of CuAlNi single crystals is measured by DSC (differential scanning calorimeter). An isothermal single interface DO3-->2H transformation arises when the specimen is quenched at a slow rate, but 2H-->DO3 transformation always proceeds with multiple interfaces due to the existence of stored elastic energy inside martensite. The elastic energy is essentially stored on the martensitic interfaces and results in A(s)-->M(f), which brings a separate spectrum of heat flow on the measured curve. The size of stored elastic energy affects the hysteresis.

CALORIMETRIC STUDY OF COLD AND THERMAL DENATURATION OF BOVINE β-LACTOGLOBULIN B

The denaturational behaviour of bovine β-lactoglobulin B has been studied in solutions containing guanidine hydrochloride by differential scanning calorimetry. The experiments have shown that complete peaks of cold denaturation can be recorded also in high concentration of protein solutions. The cold denaturation and the renaturation of the protein are reproducible, but the thermal denaturation is irreversible. The activation energy of thermal denaturation calculated is about 285 kJ/mol.

Calorimetric power measurements in the EAST ECRH system

In this paper, the measurement method of calorimetric power for an electron cyclotron resonance heating（ECRH） system for EAST is presented. This method requires measurements of the water flow through the cooling circuits and the input and output water temperatures in each cooling circuit. Usually, the inlet water temperature stability is controlled to obtain more accurate results.The influence of the inlet water temperature change on the measurement results is analyzed for the first time in this paper. Also, a novel temperature calibration method is proposed. This kind of calibration method is accurate and effective, and can be easily implemented.

A Calorimetric Study Assisted with First Principle Calculations of Specific Heat for Si-Ge Alloys within a Broad Temperature Range

Calorimetric measurements are performed to determine the specific heat of Si-xat.% Ge(where x = 0, 10, 30,50, 70, 90 and 100) alloys within a broad temperature range from 123 to 823 K. The measured specific heat increases dramatically at low temperatures, and the composition dependence of specific heat is evaluated from the experimental results. Meanwhile, the specific heat at constant volume, the thermal expansion, and the bulk modulus of Si and Ge are investigated by the first principle calculations combined with the quasiharmonic approximation. The negative thermal expansion is observed for both Si and Ge. Furthermore, the isobaric specific heat of Si and Ge is calculated correspondingly from OK to their melting points, which is verified by the measured results and accounts for the temperature dependence in a still boarder range.

CALORIMETRIC AND RAMAN SPECTROSCOPIC STUDIES ON THE INTERACTION OF LANTHANOID IONS WITH DIPALMITOYLPHOSPHATIDYLCHOLINE BILAYER

The interactions of lanthanoid ions with dipalmitoylphosphatidylcholine bilayer were studied by DSC and Raman spectroscopy.The results show that the addition of lanthanoid ions causes a considerable increase of the gel to liquid crystalline transition temperature of phospholipid and a reduction of order of lateral packing and conformation of acyl chains in SUVs.

4-28 Calorimetric Measurement of Deposited Energy by Heavy Ion Beams Impact on Diamond Target

Highly charged ions (HCIs) carrying amount of potential energy will produce some new physical phenomenabecause the potential energy will be deposited into a very small volume within a very short time. We wouldapply the calorimetric method to study the energy deposition of HCIs [1;2]. Herein we introduce the new setup forcalorimetric measurement for the potential energy deposition of highly charged ions at 320 kV Highly Charged IonsPhysics Experimental Platform.The setup was constructed by 3 parts: the Dewar, the electrical temperature controller and the main part. Thediamond target was connected to the LN2 cooled heat sink by 4 copper wires and a Platinum temperature sensorwas glued to the rear side of the target. As shown in Fig. 1.

An applicable calorimetric method for measuring AC losses of 2G HTS wire using optical FBG

We present a new calorimetric method for measuring alternative current(AC)losses of high-temperature superconducting(HTS)tapes by optical fiber Bragg grating(FBG),which is particularly well suited for the AC loss measurement of Re BCO wires,so-called the second generation(2G)HTS wires.Compared with conventional calorimetric methods,the suggested method is both free of electromagnetic disturbance,magnetic field,and fast as well as simple.Self-field AC losses are measured by the optical FBG method and the conventional lock-in-amplifier(LIA)technique,respectively.The results show that the measured AC loss is in good agreement with those measured by the electric method,thus the presented calorimetric method would be available for measuring the AC loss of 2G wire and is expected to be generalized for the measurement of AC loss or thermal performances of HTS bulk.

Calorimetric study on adsorption of hydrogen on zinc oxide

The adsorption of hydrogen on zinc oxide has been a very interesting topic. A. L.Dent and R. J. Kokes studied the kinetics and mechanism by IR, H2-D2 exchange and BETmeasurements. They found that there are two types of hydrogen adsorption, in whichtype Ⅰ is rapid and reversible whilst trpe Ⅱ is slow and irreversible. B. Fubini et al.

Novel and Simple Calorimetric Methods for Quantifying Losses in Magnetic Core and GaN Transistor in a High Frequency Boost Converter

In design and implementation of a boost converter,information on loss characteristics of switching devices and magnetic materials is a prerequisite,especially in high frequency applications.To gather such information,testing and accurate loss quantification is needed.Previous methods for measuring magnetic core loss are either only suitable for sinusoidal wave excitations or cannot separate winding loss from inductor loss.In addition,existing loss measurement approaches on the newly introduced GaN transistors are not satisfactory.In this paper,we present a new method to distinguish winding loss from inductor loss under practical excitations.This method utilizes a converter to generate the actual excitation waveforms and uses a calorimetric setup to quantify the losses.By splitting up the inductor in a converter into an air-core inductor and a magnetic-core inductor,both equipped with exactly the same winding structure,the air-core inductor loss can be used as the reference of the magnetic-core inductor winding loss.In this way,losses in the magnetic core can be determined in the actual operating condition of a converter in which the inductor is to be used.Moreover,a simple calorimetric approach for obtaining loss information of GaN transistors are is also presented.Both methods require simple setup and are easy and convenient to execute.The methods work well in assessing different high frequency magnetic core materials and measuring losses in GaN transistors at 1MHz.

Hydration Heat Evolution of Cement and Its Relation With Setting Time

In order to veritably measure the first peak of hydration heat evolution that has been illustrated important in indicating cement behavior in early hydration, an improved way of water addition into cement in isothermally calorimetric experiment is put forward. The experimental results indicated that: the magnitude of first peak of heat evolution varies from sample to sample, correlation between heat evolution during first peak of heat evolution and initial (as well as final) setting time is unsatisfactory when samples are not classified; while groups of sample classified based on strength grade represent satisfactory correlations, which indicating the existence of close relation between hydration heat evolution in much earlier hydration age and setting property of cement in rather later age. Importance of first peak in hydration heat evolution for understanding cement setting property and reasons for sample classification are also discussed in this paper.

Anisotropic Thermal Diffusivity Measurements in High-Thermal-Conductive Carbon-Fiber-Reinforced Plastic Composites

This paper presents the temperature dependence of in-plane thermal diffusivity and anisotropy distribution for pitch-based carbon-fiber-reinforced polymers (CFRPs). The measurement was performed using the laser-spot periodic heating method. The samples were unidirectional (UD) and crossply (CP) CFRPs. All carbon fibers of the UD samples ran in one direction, while those of the CP samples ran in two directions. In both UD and CP CFRPs, from -80°C to +80°C, temperature dependence of thermal diffusivity values increased as temperature decreased. In this temperature range, the anisotropic ratio between the fiber direction and its perpendicular direction of the UD CFRP was 106 - 124. During the anisotropy distribution measurement, it was found that thermal anisotropy can be visualized by scanning the laser in a circle on the sample. The thermal diffusivity of the UD CFRP in the fiber direction was 17 times larger than that in the 15°direction, and the thermal diffusivity in the other directions was lower than that in the 15°direction. The anisotropy distribution for the CP CFRP reflected its inhomogeneous structure.

IMPROVEMENT OF THE O－P THERMODYNAMIC MODEL OF THERMOELASTIC MARTENSITIC TRANSFORMATION

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几种化妆品的毒性检测

几种化妆品的毒性检测乌尼尔，尹幸念，安秀伟内蒙古自治区防疫站毒理科（呼和浩特０１００２０）我市由于使用化妆品而引起皮肤疾患的人为数不少。为了解一些化妆品的性能，于１９９１年３月至１１月对市售三种染发剂、六种洗发香波、三种防晒霜及一种美容霜进行了毒性试...

Analysis and Calculation of AC Losses Test of EAST PF Model Coil

The poloidal field model coil （PFMC） of EAST was a large NbTi superconducting coil. The PFMC was designed and constructed by Institute of Plasma Physics, CAS, and it was tested during 2003 at our institute. One of the most important performance testing items was the AC （Alternating Current） loss. It was able to measure the AC losses by the calorimetric method. The results will be useful for the evaluation of the AC losses of the poloidal coil and provide meaningful data for future operation of the EAST device.

Effects of C60 on the Glass Transition Temperature of Carbazole-based Photorefractive Polyphosphazenes

The bi-functional carbazole-based photorefractive polyphosphazenes with different content of C_（60）-doped were fabricated. The glass transition temperature（T_g） of these polymer composite materials was determined using a differential scanning calorimetric（DSC） method. According to the DSC measurement results with different heating rates, the variation of T_g and the active energy of glass transition（E_g） were analyzed in detail. The analysis results indicate that the transition region shifts to higher temperatures with increasing heating rate, and C_（60） content（below 1.0 wt%） can influence the T_g of photorefractive polyphosphazenes. The T_g first increases and then decreases with the C_（60） content（below 1.0 wt%）. The probable causes of the influence of C_（60） on T_g was proposed.

Thermochemical Parameters of 3-Chloroaniline Complexes of Certain Bivalent Transition Metal Bromides

Complexes of general formula [MBr2(3-clan)n] (where M is Fe, Ni, Cu or Zn;3-clan = m-chloroaniline;n is 1.5 or 2) were prepared and their characteristic properties, such as capillary MP;C, H, N, Br and metal contents;TG/DTG and DSC curves;and IR and electronic spectra were determined. By calorimetric measurements in solution, the values of some thermodynamic parameters of the complexes were determined. From these values, the standard enthalpies of the metal-nitrogen coordinated bonds were calculated, and the standard enthalpies of the formation of the gaseous phase complexes were estimated.

Polymer-Based Micro Flow Sensor with Alternative Electronic Signal Interfaces for Low and High Flow Rates

The qualitative and quantitative assessment of gas flow has become increasingly relevant in the use of everyday systems. The micro flow sensor, developed by Innovative Sensor Technology AG （Switzerland）, is by principle a calorimetric flow sensor produced as a micro system on a glass substrate by means of photolithography and glass etching technology. These structures are arranged as a platinum micro heater and sensor in a Wheatstone bridge. The subsequent etching process produces an exposed area of polyimide membrane that is only a few microns thick and includes the resistive sensor structure as the active area. In addition, the RTD （resistance temperature detector） technology included on the sensor allows for the implementation of a variety of electronic biasing and signal processing modes. Since the sensor can be powered and the bridge can be measured in both CTA （constant temperature anemometer） and calorimetric mode, new possibilities are presented for both low and high flow rates with regard to temperature compensation, self-calibration and self-monitoring.