Infrared spectrometer thermal

The pyrolysis of wood, oxygen chemisorption and oxidation of wood chars were carried out in a computerized coupled TG-FTIR system containing Cahn-R-100 electric balance, DuPont Model 990 thermal analyzer and Nicolet MX-1 Fourier transform infrared spectrometer. All of these sequential processes are carried out within the thermal balance without interruption. 

D Commercial COTS controlled by external computer Hybrid systems such as automated dissolution workstation with high-performance liquid chromatography (HPLC) or ultraviolet-visible (UV-Vis) interface Liquid chromatographs, gas chromatographs, UV/Vis spectrophotometers, Fourier transform infrared (FTIR) spectrophotometers, near-infrared (NIR) spectrophotometers, mass spectrometers, atomic absorption spectrometers, thermal gravimetric analyzers, COTS automation workstations... 

NMR spectra were taken in deuteriochloroform solution, using a Varian HA100 spectrometer. Thermal measurements were made with a Perkin-Elmer DSC IB differential scanning calorimeter at 40°C/min. Near-infrared spectra were measured in carbon disulfide solution with a Beckman DK 2A spectrophotometer. Gas-chromatographic analyses of reaction mixtures were carried out after conversion of the phenols to trimethylsilyl ethers by reaction with bis (trimethylsilyl) acetamide. 

Powder X-ray diffraction (XRD) patterns of the samples were carried out on a Rigaku RTP300-RC X-ray diffractometer with Cu Ka ( =1.541 SA) radiation. Infrared spectra (IR) were recorded by the KBr method on a Perkin-Elmer 1600 Series FTIR infrared spectrometer. Thermogravimetric (TG) and differential thermal analysis (DTA) curves were obtained at a heating rate of 10°C/min in air on a Seiko SSC5200 thermal analyzer. Scanning electron microscopy (SEM) was performed on a Hitachi S-530 scanning electron microscope. 

L Tb - elements of a spectrometer receive radiation from several radiators, including the spectrometer itself, while simultaneously acting as radiators. Thus, the balance of thermal radiation of any element in a spectrometer can be calculated, for example that of the sources, samples and detectors of near-, middle, and far-infrared spectrometers. 

Measurements of the gaseous sulfur dioxide released were obtained with the Total Ozone Mapping Spectrometer (TOMS Krueger, 1983) and with the Solar Backscatter Ultraviolet Spectrometer (SBUV Heath et d., 1983), both carried on the Nimbus 7 satellite. Three instruments on board the Solar Mesosphere Explorer (SME) also revealed features of the cloud the Infrared Radiometer measured the thermal emission from the aerosols, while the Visible and Near Infrared Spectrometers measured the backscat-tered solar radiation. The three instruments are limbscanning and view the atmosphere along the track of the sunsynchronous polar orbit (Barth et d., 1983 Thomas et d., 1983). Ground based and airborne spectro-photometric measurements of sulfur dioxide have also been carried out (Evans and Kerr, 1983). 

This paper reports a study to verify the relationship between functional group distribution and thermal decomposition behavior. A Fourier transform infrared spectrometer (FTIR) has been employed to obtain quantitative infrared spectra of the coals, chars, and tars produced in the devolatilization experiments. The spectra have been deconvoluted by using a computerized spectral synthesis routine to obtain functional group distributions, which are compared to the model parameters. 

Fig. 1.5. Experimental setup of the high-frequency laser vaporization cluster ion source driven by a 100-Hz Nd Yag laser for the production of ion clusters, ion optics with a quadrupole deflector, and quadrupole mass Alter for size-selection and deposition the analysis chamber with a mass spectrometer for thermal desorption spectroscopy (TDS), a Fourier transform infrared spectrometer, a spherical electron energy analyzer for Auger electron spectroscopy (AES) for in situ characterization of the clusters [73]...

The crystal structure of as prepared samples was identified by using a powder X-ray diffractometer equipped with CuKa radiation (30kV, 20mA) and a monochromator. An infrared spectrometer was used for the chemical structure analysis. Chemical composition of samples was determined by EDX analysis. To determine the content of organic species in the composites, thermal gravimetric (TG) analysis was carried out at a heating rate of 10 °C/min in air. The BET surface area was determined by measuring N2 adsorption isotherms at 77 K. The microstructure of samples was observed by FE-SEM. Diffuse reflectance spectra were recorded with a UV-vis spectrometer. 

A technique which has proven useful for our studies is that of cylindrical internal reflectance (CIR), coupled with a Fourier transform infrared spectrometer. In this study, an IBM-85 FTIR equipped with either a DTGS (deuterated triglycine sulfate) or MCT (mercury-cadmium-tellurium) detector was used. The infrared radiation is focused by concave mirrors onto the 45° conical ends of a transmitting crystal (Figure 1). The crystal may be made of any material which is optically transparent, has a high mechanical strength and high index of refraction, and is resistant to thermal shock and chemical attack. Suitable materials include ZnS, ZnSe,... 

The next component part in the infrared spectrometer is the detector. The most important types of detectors used in infrared spectroscopy are the thermal detectors. In this type of detector, radiation energy is first absorbed and then converted into heat energy. The actual measured value is an electrical voltage, which is produced or changed by the heating. Despite their higher sensitivity, photo electric detectors have a lower popularity due to the limits they have of the ana-lyzable wavelength area. 

Two types of infrared spectroscopic analysis have been applied. The first is to follow the changes in the evolved gas product infrared spectra during heating. The precursor polymer is heated in a thermal gravimetric analyzer (TGA) and the evolved gases are directed into a gas cell in the infrared spectrometer. This TGA-IR method enables us to characterize the composition of the species evolved during the thermal elimination reaction. 

The gaseous products evolved during a TG measurement are a rich source of information and these gases are readily analysed by coupling an appropriate instrument to the TG apparatus. This form of thermal analysis is often referred to as evolved gas analysis (EGA), and is discussed in Section 6.1. Mass spectrometers (TG-MS), Fourier transform infrared spectrometers (TG-FTIR) and gas chromatographs (TG-GC) may be coupled for simultaneous TG-EGA. 

Infrared spectrometers may also be combined with thermal analysis instrumentation. Thermal analysis methods provide information about the temperature-dependent physical properties of materials. However, it is not always possible to gain information about the chemical changes associated with changes in temperature by using standard thermal analysis equipment. It is possible to combine thermal analysis apparatus with an infrared spectrometer in order to obtain a complete picture of the chemical and physical changes occurring in various thermal processes [11, 12]. 

Thermogravimetric analysis enables one to continuously monitor the mass of a sample as a function of temperature and/or time. Unfortunately, the instrument cannot identify the volatile products that are evolving as temperature is increased unless it is coupled to another analytical tool such as a mass spectrometer (MS) or Fourier transform infrared spectrometer (FTIR), as discussed in Section 3.2.5. For standalone TGA it is important to gather as much information as possible about a sample from prior work, from the suppher, or from the open literature. In some instances, a more complete characterization of a sample may be possible using complementary experiments, including other thermal or analytical techniques. 

Modem PyFTlR equipment allows thermal evolution, vaporisation and pyrolysis directly in the FTTR. In direct PyFTIR the sample is located <3 mm below the beam [833,834]. Washall et al. [833] have described a cylindrical interface equipped with KBr windows, for connection of a ribbon filament pyrolyser to FTIR. Also sample cells with ZnSe windows are available for insertion into the light path of a Fourier transform infrared spectrometer for direct FTTR measurement of intricate solids. 

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