WAXS method

Casting by the lost wax method entails initially creating a core of clay covered with a layer of beeswax, and modeling the outer layer of the wax in the exact pattern of the desired cast. Once the wax pattern is made, the sequence of operations listed below is generally followed (Feinberg 1983 Ammen 1979) ... 

The molten wax method requires that the properties of a simulant are very close to those of the liquid of interest. Thus, the choice of suitable materials is limited. The method also suffers from some practical problems in preheating the wax and errors incurred by changes in physical properties of the wax during cooling after leaving the injector. Since the properties of the wax (notably surface tension and viscosity) critically influence the process of droplet formation, it may not be accurately reproduced due to the changes in these properties with temperature. Therefore, it may be required that the air in the near-nozzle region, where the key process of droplet formation occurs, be heated to the same temperature as that of the molten wax. 

A technique for the characterization of polymer crystallinity as a bulk material or around the stiff fibers/particulates in composites is based on WAXS. The WAXS method is actually more of a bulk analytical tool than a surface technique, but it has been developed mainly for monitoring crystallinity in thermoplastics and fiber composites made therefrom. 

WAX METHOD. Joyce (1Z, 2Z) has simulated a spray by using molten wax. The solid particles formed on cooling of the spray can be sieved for size-concentration analysis. 

Joyce (29) developed the wax method of spray-particle-size measurement to a high degree of perfection during 1942 to 1946. His technique is based upon the observation that paraffin wax, when heated to a suitable temperature level above its melting point, corresponds closely, in the significant characteristics of viscosity and surface tension, with jet fuel. 

The frozen-drop and the wax methods eliminate the tedious and time-consuming operations of microscopic counting of the larger droplets, and sampling errors are less likely because all of a large increment of spray can be collected and handled by employing screens and gravimetric methods of analysis. The chief limitation is that screens are not available to obtain data on particles smaller than 75 microns. Some form of microscopic count or air elutriation procedure is necessary for the smaller droplets. 

Besides royal gold jewelry, they made artistic brass weights, spoons, and boxes. They also worked copper, zinc, tin, lead, and nickel. They cast objects in brass by the lost wax method. In this process, shapes were carved in wax, then encased in clay and baked. The hot wax was poured out, leaving a ceramic mold. 

Hasson, D., and Mizrahi, J., The Drop Size of Fan Spray Nozzle, Measurements by the Solidifying Wax Method Compared with Those Obtained by Other Sizing Techniques, Trans. Inst. Chem. Eng., Vol. 39, No. 6, 1961, pp. 415-422. 

D4943-95 Standard T est Method for Shrinkage Factors of Soils by the Wax Method... 

Agarwal, U.P., Reiner, R.R., and Ralph, SA. (2013) Estimation of cellulose crystallinity of lignocelluloses using near-IR FT-Raman spectroscopy and comparison of the Raman and Segal-WAXS methods. J. Agric. Food Chertu, 61 (1), 103-113. 

Copolymers with one block of ladder-typ>e and another of conventional stmcture were investigated.Thermal properties and supermolecular stmctme were investigated by differential scanning calorimetry (DSC), small-angle X-ray scattering (SAKS), and wide angle X-ray scattering (WAXS) methods. 

The WAX method therefore appears to be a poor one for quantifying the level of exfoliation. It has, however, the utility of confirming a lack of exfoliation or the presence of intercalated tactoids. This can be enhanced by the method of sample preparation utilized. In the melt, smectite clays have a strong tendency to orient parallel to flow lines. If the X-ray... 

Although the density and WAXS methods of determining the degree of crystallinity of semi-crystalline polymers are widely used techniques several others have been employed with varying degrees of success. One techni-... 

WAXS method is considered as a simple and convenient method for determining the size of the crystallites without their isolation from cellulose. The X-ray measurement method of average size of small crystallites is based on Scherrer s equation ... 

To determine the actual sizes of crystallites, an improved WAXS method should be used taking into consideration the contribution both of instrumental factor (h] and also of paracrystalline distortions (A] in the experimental width [5] of the peak ... 

To study the structure of NCD hy WAXS method, samples of amorphized cellulose are required. These samples can be prepared by ball-milling, saponification of cellulose acetate in non-water alkali solutions, etc. (Jeffries, 1968). The typical X-ray diffractogram of amorphous cellulose has a wide peak with maximum at 20 = 20-20.5° (Fig. 7.9). Using the modified Scherrer s equation for amorphous pol5miers with the shape factor K = 1.8, an average size of partially ordered mesomorphous clusters of NCD can be estimated = 1.8-1.9 nm. Average Bra s... 

Relatively simple WAXS method for estimating the MFA is a measurement the maximum intensity of the (200]-peak [/y], when the fiber is oriented vertically and minimum intensity of the peak [/jj], when the fiber is oriented horizontally. From the intensity measurements an orientation index F = 1 - (/h//v3 is found, and then average MFA of the fibers is calculated by the following equation ... 

Equations [7.33] to [7.36] are the base for the determination of the degrees of amorphicity and crystallinity of cellulose from results of water vapor sorption. The values of Y and X calculated from results of water vapors sorption were close to these structural characteristics obtained by the WAXS method. 

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