Laboratory characterisation

A laboratory characterisation was carried out, during which the performances of the optical fibre sensor were carefully verified and compared with those of the Tonocap. The results showed the capability of the optical fibre sensor to detect CO2 correctly even in the presence of rapid changes of the order of 1 minute. 

Dabron, G.R. and Rampling, T.W., 1988, A literature review of published research on refuse derived fuel and its components. Appendix A the laboratory characterisation of refuse derived fiiel. Report LR643 (MR), Warren Spring Laboratory. 

In addition to numerous mixed-cation manganese phosphate minerals, laboratory-characterised varieties include... 

Sophisticated models attempt to relate microbial yield to the rate of carbohydrate fermentation and rate of passage, the theoretical growth rate, the energy cost of bacterial maintenance and the form of nitrogen available to the rumen microorganisms. Many of the relationships involved in such calculations are based on laboratory characterisation of the food, and the value of the model will depend on the validity of the relationships between the laboratory determinations and the values used in the models. 

It is interesting to note one recent innovation in the industrial manufacture of HPAMs specifically for use in lOR Marathon has developed a polymer manufacturing process which is transportable to the site of the polymer flood (Milton et al, 1983). This gives considerable flexibility in terms of quality control of the product for this specific application. Laboratory characterisation of the polymer produced in this process is described by Milton et al (1983) and Argabright et al (1982). 

J. G. Baet2, Characterisation of Advanced Solid Pocket No ffe Materials (SAMSO-TR-75-301), Air Eorce Rocket Propulsion Laboratories, Edwards AEB, Calif., Dec. 1975. 

To carry out a spectroscopy, that is the structural and dynamical determination, of elementary processes in real time at a molecular level necessitates the application of laser pulses with durations of tens, or at most hundreds, of femtoseconds to resolve in time the molecular motions. Sub-100 fs laser pulses were realised for the first time from a colliding-pulse mode-locked dye laser in the early 1980s at AT T Bell Laboratories by Shank and coworkers by 1987 these researchers had succeeded in producing record-breaking pulses as short as 6fs by optical pulse compression of the output of mode-locked dye laser. In the decade since 1987 there has only been a slight improvement in the minimum possible pulse width, but there have been truly major developments in the ease of generating and characterising ultrashort laser pulses. 

All such animal procedures suffer from the obvious and basic problem that laboratory animals do not behave like humans and that humans cannot reliably interpret their reactions and behaviour. Thus we know that Parkinson s disease is caused by a degeneration of the dopaminergic nigrostriatal tract but its lesion in animals does not produce any condition which resembles human Parkinsonism, except in primates, even though there are functional tests (e.g. rotational movements) which readily establish that loss of dopamine function and also respond to its augmentation (Chapter 15). By contrast, there are many ways, e.g. electrical stimulation and the administration of certain chemicals, to induce convulsions in animals and a number of effective antiepileptic drugs have been introduced as a result of their ability to control such activity. Indeed there are some tests, as well as animals with varied spontaneous seizures, that are even predictive of particular forms of epilepsy. But then convulsions are a very basic form of activity common to most species and epileptic seizures that are characterised by behavioural rather than motor symptoms are more difficult to reproduce in animals. 

The characterisation of the toxicity associated with a specific chemical is invariably dependent on feeding the chemical to laboratory animals in statistically-based lifetime bioassay, guidelines for which have been agreed at the international level by the OECD (OECD, 1981) and the IPCS (IPCS, 1999), and which are undertaken strictly in compliance with the principles of good laboratory practice (GLP). The animals used in long-term bioassays are... 

The fine chemical industry has been characterised for decades by batch processes in laboratories as well as in production plants. Owing to the requirement of high flexibility (capacity,... 

Zn Mossbauer effect measurements are technically difficult to perform, and so far only few laboratories, mainly those in Munich [68-71] and St. Petersburg (see Sect. 7.2.2.4) have published significant contributions on the characterisation of zinc containing compounds and metallic materials with Zn Mossbauer spectroscopy. Selected work is briefly discussed in the following sections. 

GC-IMS-MS instruments are ideally suited for laboratory studies, as a complex mixture can be separated ionisation in relatively clean systems can take place and the identity of the ions can be studied and verified by mass spectrometry [315]. However, the cost of such systems is quite prohibitive, and their complexity confines their utilisation to the laboratory. In GC-IMS-MS, the gas chromatograph is used to preseparate the components of the sample, with the IMS used as its detector. The ions that constitute the mobility spectrum are then further characterised by MS. 

The first application of ANNs to pyrolysis mass spectra from biological samples was by Goodacre, Kell, and Bianchi.96,97 This study permitted the rapid and exquisitely sensitive assessment of the adulteration of extra-virgin olive oils with various seed oils, a task that previously was labor intensive and difficult. Since this study other laboratories have increasingly sought to apply ANNs to the deconvolution and interpretation of pyrolysis mass spectra, the aim being to expand the application of the PyMS technique from microbial characterisation to the rapid and quantitative analysis of the chemical constituents of microbial and other biological samples. 

Violent explosions which occurred at —100 to —180°C in ammonia synthesis gas units were traced to the formation of explosive addition products of dienes and oxides of nitrogen, produced from interaction of nitrogen oxide and oxygen. Laboratory experiments showed that the addition products from 1,3-butadiene or cyclopentadiene formed rapidly at about — 150°C, and ignited or exploded on warming to —35 to — 15°C. The unconjugated propadiene, and alkenes or acetylene reacted slowly and the products did not ignite until +30 to +50°C [1], This type of derivative ( pseudo-nitrosite ) was formerly used (Wallach) to characterise terpene hydrocarbons. Further comments were made later [2],... 

Figure 13 shows a full NMR spectrum of PET, in TCE solvent, acquired at 100°C. Resonances a and b are from the terephthalate and ethylene glycol derived protons, respectively. Resonances c and d arise from the protons in diethylene glycol (DEG), which is formed as a side reaction in the PET polymerisation process. An expansion of the ethylene glycol-based region of the spectrum is shown in Figure 14. Proton NMR techniques have been described for characterising end groups [42-44], the methodology below being that which is used in our laboratory.

A combination of NMR spectroscopy and MALDI-TOF MS is commonly employed in our laboratory for the characterisation of PPG polymers. Analysis of di-hydroxyl end-capped PPG (18) is initially described. The [H NMR spectrum [54] can be used to confirm the backbone structure of the polymer, as can be seen in Figure 22 (a and b are from the backbone of the polymer, with c from the methyl side chains). Peaks of low intensity, downfield of those from the backbone of the polymer, in the HNMR spectrum may be used to identify and quantify the allyl functionality in the polymer [55]. These resonances (d, e and f) are... 

UV/visible spectroscopy of organometallic transients has been extremely important for kinetic measurements on previously identified species, but the spectra are less valuable for structural identification since most spectra show broad and featureless bands. One way round this problem has been to utilise matrix IR spectroscopy for characterisation and to use the data obtained from the matrix UV/visible spectrum to monitor the room-temperature kinetics. A more satisfactory method is to record the IR spectra of transients directly and there has been much activity in both gas phase and solution organometallic chemistry this field has been recently reviewed ( 35). In our laboratory,... 

Center for Healthcare Technologies at Lawrence Livermore National Laboratory in Livermore, potentially capable to measure pH at or near the stroke site29. The probe is the distal end of a 125 pm fibre tapered up to a diameter of 50 pm. A fluorescent pH-indicator, seminaphthorhodamine-1-carboxylate, is embedded inside a silica sol-gel matrix which is fixed to the fibre tip. Excitation of the dye takes place at 533 nm and the emission in correspondence of the acid (580 nm) and basic (640 nm) bands are separately detected. The use of this ratiometric technique obviates worrying about source fluctuations, which have the same effects on the two detected signals. The pH sensor developed was first characterised in the laboratory, where it showed fast response time (of the order of tens of seconds) and an accuracy of 0.05 pH units, well below the limit of detection necessary for this clinical application (0.1 pH units). The pH sensor was also tested in vivo on rats, by placing the pH sensor in the brain of a Spraque-Dawley rat at a depth of approximately 5 mm30. 

Chromatographic procedures applied to the identification of proteinaceous paint binders tend to be rather detailed consisting of multiple analytical steps ranging from solvent extractions, chromatography clean up, hydrolysis, derivatisation reactions, and measurement to data analysis. Knowledge of the error introduced at each step is necessary to minimise cumulative uncertainty. Reliable results are consequently obtained when laboratory and field blanks are carefully characterised. Additionally, due to the small amounts of analyte and the high sensitivity of the analysis, the instrument itself must be routinely calibrated with amino acid standards along with measurements of certified reference proteins. All of these factors must be taken into account because many times there is only one chance to take the measurement. 

New chromatographic technologies are widespread in the scientific laboratories of museums and collections, so that there are increasing numbers of publications aimed at the characterisation of proteins in art. Table 9.4 lists some of the most recent applications in the field but it is not exhaustive as lots of works are presented at conferences and workshops. 

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