Aluminium sampling

To find now the optimum excitation frequency, we calculate the first derivative of Equ. (3.1) to find the maximum value of the response field of cracks in different depths (Fig. 3,1). For example a crack (20 x 0.6 x 0,2 mm) in a depth of 9 mm in an aluminium sample (a = 20 MS/m) could be found with highest SNR when using a frequency of 260 Hz Here a double-D... 

Sample cells include Lindemann/capillary tubes (normally < 1 mm in diameter) and aluminium holders. In the latter, thin aluminium windows sandwich the sample in a cylindrical aluminium sample holder. The diffraction from the aluminium is observed in this case, and may be used as a calibration standard. For low-temperature materials, the aluminium window can be replaced by the polymer Kapton. Beryllium may also be used [14]. Sample volumes of between 50 and 100 pL are typically required. 

For example, suppose that traces of iron in an aluminium sample are to be determined. 59 Fe is characterised by 7 emission at 1.29 MeV. Aluminium under irradiation will yield 24Na, which is responsible for a 7 ray situated at 1.37 MeV via the reaction 27AI(n,a)24Na (r = 15h). Here, a time gap of several days between the end of radiation and measurement permits enough time for the aluminium to disappear. 

A method has been proposed for preconcentration of traces of the more volatile elements (e.g., Zn, Cd, Tl, In, Pb) by heating samples in quartz tubes to about 1,000 C in a stream of hydrogen. The sublimed metals are collected on a cold-finger. Many metal halides have been volatilized from aluminium samples by heating to 990 C [110]. Volatile acetylacetonates and other B-diketonates have also been utilized for the separation of metals [111]. 

L. Cecchetto, A. Denoyelle, D. Delahoughse, and J.-P. Petit, A silane pre-treatment for improving corrosion resistance performances of emeraldine hse-coated aluminium samples in neutral environment App/. Surf. Set, 254, 1736-1743 (2008). 

The results of the dilatometer runs for sample ID, 2A and 3A are shown in figure 8. They are representative for all the samples in the different groups. For sample 2A there is a sudden and large increase in length at 670°C which is due to the melting and nitridation of aluminium. Samples ID and 3A has a much smaller expansion and over a larger temperature range. 

Select a modulation period of 40-100 s. For most samples in standard crimped aluminium sample vessels 60 s is the recommended period of oscillation. Longer periods may be necessary for larger mass hermetic sample vessels. In the presence of a high thermal conductivity purge gas periods as short as 40 s can be used. Periods of 30 s or less are generally not recommended. 

Xanthan gum is an anionic polysaccharide secreted by certain bacteria which in the dry state does not exhibit a first-order phase transition. In the presence of a small amount of water a glass transition, cold crystallization, melting and a liquid crystal transition are observed. Figure 5.28A presents DSC heating curves of water-xanthan gum systems with various water contents. A 3 mg sample was hermetically sealed in an aluminium sample vessel, cooled from 320 to 150 K at 10 K/min and subsequently heated at 10 K/min. With reference to Section 5.1, the transition temperatures are defined as follows glass transition temperature and melting and crystallization temperatures 7p and, respectively. The... 

Topographic and fluorescence NSOM image for aluminium sample exposed to aqueous solutions with fluorescein. 

The application of the coatings by dipping the roughened aluminium samples in a diluted polymer solution seems to be suitable and effective to provide large aluminium sheets with superhydrophobic surface properties. Coating films to control the surface properties, e.g. the wetting behavior, and to prevent metal substrate... 

The aluminium samples modified by methacrylate copolymer films were investigated by XPS to obtain their chemical surface composition. Besides the elements of the copolymer film (carbon, fluorine) also the elements of the oxidic substrate material (aluminium and sulphur) were detected. The detection of alumiiuum indicates a very thin copolymer layer or a ruptured copolymer film, which did not fully cover the substrate material. Traces of sulphur (found as sulphate S04 ) were incorporated during the anodization process. Both layers contained oxygen, but it was less in the polymer film than in the oxide layer. To calculate the degree of coverage, 4> the relative atomic concentration (at%) of carbon (the key element of the polymer layer) was related to the sum of the relative atomic concentrations of carbon and aluminium (the key element of the substrate material) ... 

Of course, the molecular orientation and the properties of the polymer and copolymer films control the surface wettability by water. Additionally, it is noteworthy that XPS measurements on coated aluminium samples did not show any traces of silicon. This ensure that polysiloxanes were absent and did not prevent the wetting by water. In the case of polymer-coated siUcon wafers the absence of silicon signals also indicates that the coating films were closed and dense. 

Comparison In a galvanic couple (316/112 + 6063/114), the aluminium sample 6063/114 had more deposited scale on the coupled surface than did the stainless steel coupon 316/112 ... 

Since DSC measures heat capacity directly, rapidly, and accurately, it is an ideal technique for the determination of Tg. The calorimeter accepts polymers in any form (powder, pellet, or fibre), and only a few milligrams of sample are required. Samples are placed in a standard aluminium sample pan, crimped by a crimping press to ensure good thermal contact, placed in the sample holder, and scanned at an appropriate rate over the temperature range of interest. 

Examination by neutron and X-ray diffraction showed no detectable crystalline fraction. The recrystallisation temperature, as checked by differential thermoanalysis, is 640 K. The sample was hydrogenated by exposing it to 47.7 bar H2 gas at 373 K within the QNS aluminium sample holder, which was sealed after thermal equilibrium was reached. The resulting composition was Pdg Si2QH2 at 373 K and 130 20 2 9 according to pressure com-... 

The amorphous ribbons have been packed inside a flat Aluminium sample holder which is fitted inside heating and cooling loops whese temperature can be regulated between 77 K and 650 K within 1 K. The plane of the sample holder made an angle of 135 with respect to the incident beam. 

Core vault gas corrosion rig Recirculation of vault gas over in-core zirconium and aluminium samples... 

The first application is to detect grain boundaries in an aluminium sample. 

ISO 8007 1985. Carbonaceous materials used in the production of aluminium - sampling from cathodic blocks and prebaked anodes - General. 

Boron concentration (ng/g) in an aluminium sample that yields at the end of an irradiation (1 mA intensity, irradiation time = one half life) at the indicated energy an activity of 100 desintegrations/min... 

The procedure of Mortier et al. (32) for the determination of boron in aluminium and aluminium-magnesium alloy is as follows The sample is irradiated for 20 min with a 2 uA beam of 7 MeV deuterons, which are degraded to 5.3-5.7 MeV, and a surface layer is removed by chemical etching (2.3.1). To separate the sample is dissolved in an oxidizing mixture of phosphoric acid, sulphuric acid and potassium dichromate. The C02 released is absorbed in 0.5 M sodium hydroxide and the activity measured with a t-t coincidence set-up. A pure decay is obtained. The chemical yield was checked by comparing, in a separate experiment, the activity of an aluminium sample, doped with 5000 tig/g of boron, measured instrumentally and after chemical separation. The yield was 100 %. 

Accurate results were also obtained using the methylene blue method as described by Meier et al. (20). However, as it is the case for most of the photometric methods critical examination is required to avoid errors due to small alterations in the operational conditions (8). Also the correction for blanks can be a problem, especially when the method is used near its detection limit. This was demonstrated within the above BCR round robin a first result of (0.30 0.12) g/g was obtained for the same aluminium as above. When a purer aluminium sample, accurately characterized with charged particle activation analysis, was used to determine the blank, a value of (1.27 + 0.08) tig/g was obtained. 

An etched 0.5 g aluminium sample is spiked with a standard solution of boron enriched in B (1.202 10 at.B/g B = 88.06 at.%), and dissolved in 2 ml concentrated nitric acid (suprapur) at 70 C under addition of 1 ml hydrochloric acid (suprapur) every 10 to 15 minutes in order to prevent excessive foaming. After addition of 6 ml hydrochloric acid a clear solution is obtained. To this solution 10 g methanol (purified by distillation over a mixture of sodium hydroxide and mannite) is added, and boron is distilled at 95°C in the form of trimethyl borate. After dilution to 20 ml with water and addition of 2 Mg mannite, the solution is evaporated down to 0.5-1 ml at 60°C. 

Cu Al ratio =5 1 The aluminium sample is introduced into the molten... 

This phenomenon is especially observed if, for example, aluminium samples weighing more than 2 g are used, at a 5 1 bath metal to aluminium ratio, irrespective of whether the bath metal used is copper, platinum or palladium. As would be expected, the latter two metals have exhibited this effect particularly readily (Pp = 21.45 and Pp = 12). The larger the aluminium samples used, the more pronounced this problem is. It cannot be eliminated by taking larger melts for the bath, corresponding, say, to a bath/sample ratio of 9 1. 

It has been possible to overcome these difficulties in a very simple manner, by interposing a glass tube so as to raise, by about 30 cm, the device for introducing the samples, which is usually located immediately above the upper edge of the reaction furnace in the commercially available apparatus. This has the effect of causing the aluminium sample, as it falls into the copper bath, to penetrate more deeply into the latter, so that the layer formation described occurs either nor at all, or no longer to a harmful extent. This method made it possible to analyse 5 g samples (8 mm in diameter and 50 mm long) without any problems, in... 

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