Preparation of Specimens

The specimens for measurements of the flexural moduli were prepared by injection molding using a Sumitomo NESTAL injection molding machine (0.5 ounce).1 

A Toyo Boldwin Tensilon UTM-4-200 machine was used for these measurements. Determinations were performed according to ASTM D790 by using injection molded specimens with a thickness of 1/32 in. 

1 An ounce is a unit used to represent the capacity of an injection molding machine, showing the polystyrene equivalent weight of polymer for one shot . 

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Aluminium is widely applied for decorative and protective requirements, while cadmium , zinc and titanium have been applied to ferrous materials chiefly for their protective value. The method finds particular application in the plating of high-tensile steels used in aviation and rocketry, car fittings and lamp reflectors, and gramophone record master discs, as well as in the preparation of specimens for electron microscopy and in rendering insulated surfaces electrically conducting, e.g. metallising of capacitors and resistors. 

A convenient size for a circular coupon is 3 8 cm dia., a thickness of 0 - 32 cm and a central hole of 1 1 cm. Although inherent in the philosophy of corrosion testing, the use of coupons with surfaces that simulate those in service has been found to be unsatisfactory owing to irreproducibility, and the standard procedure normally adopted is to abrade down to 120-grit. ASTM Method G4 1984 gives details of preparation of specimens, evaluation of replicate exposures and the application of statistical methods. 

It is that simple. Understanding penetration is vital to seeing why the preparation of specimens sometimes (often) turns out other than what we expect or desire. Penetration of all other fluids after the fixative also must be considered. One of the purported consequences of fixation is to make the tissue more... 

Finally, photomicrography is the culmination of the preparation of specimens for optical microscopy. This is a very technical area requiring proper illumination (41-43), focusing, choice of films, as well as exposure and appropriate film development. This critical area of microscopy should see continued technological innovations as much of photomicrography is being computerized (44,45). This effort is witnessing the concomitant... 

While concepts like hue and purity easily lend themselves to verbal description, major difficulties arise in any attempt to discuss color depth or depth of shade. The only way to deal with this concept (as with other aspects of color) is to create specimens having the properties discussed. For this reason, a collection of samples equal in color depth was prepared around 1935 so that the fastnesses of various dyes could be meaningfully tested [7]. Studies by Raabe and Koch [5] and by Schmelzer [6] suggest that equal difference (or distance) from white is an essential criterion in selecting specimens of equal color depth. Some color-depth levels are set apart as standard depths of shade (SD) [6]. These find use particularly in the preparation of specimens for fastness testing they permit a consistent way for the presentation of different colorants and describing their effectiveness under various service conditions. 

Particular techniques and instruments may, of course, be required for special purposes for instance the preparation of specimens for specific examination (for example, metallographic examination) and tests of their polishing, cutting, drawing, rolling, etc. 

Jenkins, R., D.K. Smith, and V.E Bull ike A Practical Guide for the Preparation of Specimens prX-Rav Fluorescence and X-Ray Diffraction Analysis. John Wiley Sons, Inc., New York. NY, 1997. 

NOTE Preparation of specimens requires that dimensions be measured precisely. It is assumed that the dimensions of the compressed specimen are small with respect to the dimensions of the contacting surfaces (plates) to ensure that the sample remains in contact with the plates. Occasionally, it is desirable to compress a sample in its natural state (i.e., no specimen cutting). 

Figure 1. Sample geometry used in the preparation of specimens for interfacial analysis.

Preparation of Specimens for Mechanical Measurements. The specimens for mechanical testing were obtained by blending the powdered polymer with 1.5 phr of Ba-Cd stabilizer, 5 phr of CaC03, and 0.5 phr or lubricant (stearic acid). The dry blend was processed in a roll mill at 200°C for 5 minutes. The 1-mm sheets obtained were preheated in an oven at 200°C for 5 minutes and molded in a molding press at a pressure of 80-100 kg/cm2. The specimens were obtained by milling with suitable equipment. 

See preparation of specimens for mechanical measurements in text. c See Table I. 

The most common densification method is the gas-pressure sintering which guarantees better reproducibility and improved properties by only moderate increase in production costs compared to pressureless sintering. The first dense Si3N4 ceramics were produced by hot pressing [13]. Nowadays it is used for the preparation of specimens in materials development or for some applications where components of simple geometries and low quantities are required. 

Perret, D., Leppard, G.G., Muller, M., Belzile, N., De Vitre, R.R. and Buffle, J. (1991) Electron microscopy of aquatic colloids non-perturbing preparation of specimens in the field. Water Res., 25, 1333-1343. 

In electron microscopy as in any field of optics the overall contrast is due to differential absorption of photons or particles (amplitude contrast) or diffraction phenomena (phase contrast). The method provides identification of phases and structural information on crystals, direct images of surfaces and elemental composition and distribution (see Section H below). Routine applications, however, may be hampered by complexities of image interpretation and by constraints on the type and preparation of specimens and on the environment within the microscope. 

F. Preparation of Specimens. For observation by SEM, tissue and cell samples. must be carefully dried under conditions which preserve the cell surface features. This Is generally accomplished by fixing, dehydrating, and critical point drying the specimens. 

Buhrke, V.E., Creasy, L.E., Croke, J.F., Feret, F., Jenkins, R., Kanare, H.M. Kocman, V. (1998) Specimen preparation in X-ray fluorescence. In Practical Guide for Preparation of Specimens for X-ray Fluorescence and X-ray Diffraction Analysis. New York Wiley-VCH, pp. 59-122. 

ISO 9227 [1] does not specify in detail many necessary parameters and does not determine the precision of such a test method. The precision and accuracy of corrosion determination are influenced by many factors preparation of specimens, conditioning, removal of corrosion products, cleaning, drying, etc. In literature on the corrosion tests we failed to find any information concerning the quality of corrosion tests results. The aim of this paper is to call attention to the problems in the corrosion measurement data quality and the necessity to evaluate the uncertainty for measurement results. We attempted to show the main components of uncertainty of the result in such a measurement on the basis of the experimental evaluation of the corrosivity of the spray test corrosion cabinet by means of reference specimens. 

Kim et al. [44] reported results from a similar study of the decompositions of Mg(OH)2 and MgCOj in the TEM. They were able to determine in detail the product/reactant orientation relationships, by careful preparation of specimens, using ion-beam milling where necessary. They detected no intermediate phase in either decomposition. The decomposition of Mg(OH)2 produces MgO with a single orientation relationship to the substrate, while the decomposition of MgCOj yields MgO in two principal orientations. These topotactic relationships are explained in terms of the orientations of oxygen octahedra in the reactants and product. 

Preparation of specimens often is the most tedious step in TEM examination. To be electronically transparent, the material thickness is limited. We have to prepare a specimen with at least part of its thickness at about 100 nm, depending on the atomic weight of specimen materials. For higher atomic weight material, the specimen should be thinner. A common procedure for TEM specimen preparation is described as follows. 

We thank Fine Science Tools Inc (Vancouver, Fax 415-349-3729) for providing us with precision forceps used for the preparation of specimens. We thank Faulding Imaging for providing us with an Olympus Provis Research Microscope system at a reduced price... 

Fig. 4 SFM images of dried aqueous solutions of PLLx-fc-PAspy at different pH preparation of specimens not specified. Reprinted with permission from [24], copyright (2005) American Chemical Society...

Not all failure analysis concerns devices that have been completed, but this Is often the case. At the very least, tests which Indicate a failure are often several steps downstream from what would be the optimum point for AES analysis. This means that preparation of specimens Is often crucial to efficient and unambiguous analysis. Specimen handling for AES usually requires more care than ts required for other analytical techniques ( 34 ). 

A.J. Morgan, Preparation of Specimens Changes in Chemical Integrity, in X-ray Microanalysis in Biology (ed. M. A. Hayat), University Park Press, Baltimore, 1980, pp. 65-165. 

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