Instrument Model

As shown in Sect. 4.2 the instrument model is comprised of a sequence of semiindependent modules. In this section the different modules are described and the connections between them shown. 

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All S FG spectra were obtained by averaging 50 400 pulses per data point and were normalized against the intensity of the visible and infrared inputs, which were simultaneously monitored by a power meter (Oriel instruments. Model 70833 and 70811) and Si photodiode, respectively. 

Valeo Instruments, Model EL6W six-port with electronic actuator... 

Noncondensable gases leaving the condensation vessels were depressurized (by means of an electronic back-pressure, Brooks Instrument model 5866), totalized (by means of an on-line flow gas meter, Ritter model TG05-5), and periodically analyzed with an on-line GC (Hewlett-Packard model 6890) equipped with three columns and two detectors for the analysis of Cj-C10 hydrocarbons (A1203 plot capillary column connected to a flame ionization detector), H2, CH4,... 

Thermal Analysis. The DuPont Instruments Model 9900, computer controlled thermal analyzer and Model 951 TGA module were used in the experiments, using a gas flow rate of 100 cc/min. Experiments were performed in dynamic and isothermal mode using air and argon. 

Molecular weights were determined using a Waters high-pressure GPC instrument (Model 6000 A pymp, a series of five p-Styragel columns (10s, 10s, 10, 103, 500 A), Differential Refractometer 2401 and UV Absorbance Detector Model (440) and a calibration curve made by well fractionated polyisobutylene standards. 

General. Toluene, chlorobenzene, and o-dichlorobenzene were distilled from calcium hydride prior to use. 4-Dimethylaminopyridine (Aldrich Chemical Co) was recrystalled (EtOAc), and the other 4-dialkylaminopyridines were distilled prior to use. PEG S, PEGM s, PVP s, and crown ethers were obtained from Aldrich Chemical Co., and were used without purification. BuJ r and BU. PBr were recrystallized (toluene). A Varian 3700 VrC interfaced with a Spectraphysics SP-4000 data system was used for VPC analyses. A Dupont Instruments Model 850 HPLC (also interfaced with the SP-4000) was used for LC analyses. All products of nucleophilic aromatic substitution were identified by comparison to authentic material prepared from reaction in DMF or DMAc. Alkali phenolates or thiol ates were pre-formed via reaction of aqueous NaOH or KOH and the requisite phenol or thiophenol in water under nitrogen, followed by azeotropic removal of water with toluene. The salts were transferred to jars under nitrogen, and were dried at 120 under vacuum for 20 hr, and were stored and handled in a nitrogen dry box. 

FIGURE 4 Comparison of voltage—current behavior between two different instrument models. Neutral capillary, 50 mm i.d. T 20°C, Electrolyte HS a-CD 2% (w/v), 18 crown 6 ether lOmM, methanol 5% (v/v), H3PO4 l5mM, instruments Beckman Coulter P/ACE MDQ and Agilent 3D CE (unpublished). 

A comparability study using two Beckman CE instrument models (MDQ vs. PA 800) was performed to assess instrumental comparability. In this study, p7 values were determined for an antibody using each model. As shown in Table 8, the two instruments produced comparable pi values and comparable % corrected areas for each group of peaks. 

Estimation of Molecular Weight Distribution of Polyamide Blocks. The molecular weight distribution of the polyamide blocks was estimated by gel permeation chromatography (GPC) using two instruments, model HLC-802R (Toyo Soda Industry Co., Ltd.) and model GPC-2i U (Waters Associates, Inc.). Polystyrene and nylon oligomer were used as standards. 

The instrument models available differ both in hardware and softv/are equipment the simplest unit, the XTM/2, is purely a measuring or display device that cannot control vacuum coating. 

The proton magnetic resonance spectrum of indinavir sulfate shown in Figure 12 was obtained using a Bruker Instruments model AMX-400 NMR spectrometer operating at a frequency of 399.87 MHz as an approximate 4.16 % w/v solution in deuterium oxide. The HOD reference (chemical shift equal to 4.8 ppm) was used as the reference. Signal assignments are tabulated Table 7, following the numbered structural formula below [11]. 

From each batch the crushing strength of 10 tablets was measured using a Schleuniger instrument (model 4M, Dr.K. Schleuniger, CH-Zurich). 

A differential scanning calorimeter (DSC), Dupont Instrument, Model DSC2910, was used to determine the glass transition temperatures. Thermo-gravimetric analyses were carried on a thermogravimetric analyzer (TGA), TA Instruments, Model Hi-Res TGA 2950. 

Accuracy and precision vary with instrument model and total, initial, sample size, and sample preparation. A 0.05% accuracy and a precision of 0.1 /xg can be achieved with a electrobalance [6]. Reproducibility between runs, except in relatively pure materials, is usually significantly poorer (see Notes section). 

The optimized parameters, which affect the signal quality, change from instrument model to instrument model and from brand to brand. Examples are source... 

Figure 12.9—OpticaI scheme of a spectrofluorimeter having two detectors, one of which is used to control the intensity of the light source. A fraction of the incident beam is reflected by the beam splitter and monitored by a photodiode to control the intensity of the incident beam. Comparison of the signals obtained from both detectors allows the elimination of any drift in the light source. This procedure, for single beam instruments, gives approximately the same stability as with double beam instruments. (Model F4500 reproduced by permission of Shimadzu.)...

Figure 13.11—Scanning electron microscopy (SEM) accompanied by X-ray fluorescence analysis. Secondary electron image of a cross-section of a supraconducting polycrystalline ceramic with oriented grains of oxide BiPbiSriCaiCurO, (Philips instrument, model XL30FEG). Energy emission spectra corresponding to the matrix and to a 5 pm-long inclusion (bottom). It should be noted that it is possible with this technique to obtain the composition at a precise point on the sample (Link-Oxford analyser) (study by V. Rouessac, reproduced by permission of CRISMAT. University of Caen).

FT-Infrared spectroscopy was accomplished employing KBr pellets, using a Galaxy Series FT-IR 4020, Mattson Inst., Madison, WI. Thermal analysis was done employing a Dupont Thermal Instrument Model 990 employing a heating rate of 20 °C/min and a gas flow rate of 0.1 1/min. 

Recent results obtained during analysis of the VX hydrolysate produced at the Chemical Agent Munitions Disposal System for the planned SCWO EST indicate that the hexane extraction method can repeatably achieve a detection limit of less than 20 ppb (NIVA Consultants et al., 1999). However, this method not only requires approximately six hours to complete under optimum conditions, it also appears to be sensitive to both the technician performing the analysis and the laboratory (e.g., instrumentation model) where the analysis is carried out. These limitations suggest that further specification and validation will be necessary to achieve reliable results for routine use. 

Fj, F2, Brooks Instruments Model No. 5812 mass flow sensor and... 

The type of instrument, (model, serial no., etc.) should be recorded on the field observation sheet. Ideally, all instruments used in this survey should be calibrated. This may be done before or after the FOREGS field sampling. Ameeting will be arranged in a country where there are calibration pads. 

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