Impact matrices

Erosion/Deposition Impact Matrix and Map. Methods applied in this semi-quantitative assessment involved mapping depositional features using high and low altitude imagery, numerical ranking of land use activity impacts and construction of problem matrixes. The information generated in these first steps were applied to the Universal Soil Loss Equation (15-16),... 

Results. Using the information generated in the analysis, an erosion/deposition impact matrix was developed as shown in Table 3 (14,15). The horizontal axis... 

The impacts resulting from each scenario and the advantages and disadvantages of each measure (alternative) have to be estimated by computing tlie values the indicators take for each alternative. The estimation is done using tlie model calibrated during the previous step. At the end of this step an impact matrix is produced whose elements are the indicator values for each scenario and alternative (see Figure 4.2.4). This serves evaluation and comparison of results. 

Given the impact matrix, the goal of this step is to detennine the value that each sector assigns to each alternative. A number of evaluation techniques exist which can assist file analyst in reaching this goal (e.g. multi-attribute value theory and analytic hierarchy process see Soncini-Sessa et al., 2007a, 2007b). 

Fig. 6.7 Environmental Impact Matrix for a Phosphate Mining Lease.

Fig. 3 Refraction values of both (0°+ 90°) fiber directions with respect to impact energy per layer. The fiber/matrix debonding of CFRP laminates correlates significantly to the impact energy per volume (energy density).

The transition matrix T(b)f is therefore the probability of scattering particles with impact parameter b. B2.2.6.4 DIFFERENTIAL CROSS SECTIONS... 

Impact polystyrene contains polybutadiene added to reduce brittleness. The polybutadiene is usually dispersed as a discrete phase in a continuous polystyrene matrix. Polystyrene can be grafted onto rubber particles, which assures good adhesion between the phases. 

The impact of the fast atoms on the solution surface results in desorption of secondaries (positive ions, negative ions, and neutrals) into the low-pressure gas-phase region above the matrix surface. 

The impact of a primary beam of fast atoms or ions on a target matrix (substrate and solvent) causes desorption of molecular or quasi-molecular ions characteristic of the substrate. The process is called FAB for atom bombardment or LSIMS for ion bombardment. 

Mechanical Properties. Properties of typical grades of PBT, either as unfiUed neat resin, glass-fiber fiUed, and FR-grades, are set out in Table 8. This table also includes impact-modified grades which incorporate dispersions of elastomeric particles inside the semicrystalHne polyester matrix. These dispersions act as effective toughening agents which greatly improve impact properties. The mechanisms are not fiiUy understood in all cases. The subject has been discussed in detail (171) and the particular case of impact-modified polyesters such as PBT has also been discussed (172,173). 

There is extensive Hterature on PC blends with ABS, and blends of PC with related materials such as SAN, methacrylate-butadiene—styrene (MBS) emulsion-made core-shell mbber modifiers (297—299), and other impact modifiers. One report reviews some of these approaches and compares PC blends based on emulsion vs bulk ABS (229). In PC—ABS blends, no additional compatihili er is used, because of the near-miscihility of the SAN matrix of ABS and PC. 

Mechanical and Chemical Properties. Colorants, especially pigments, can affect the tensile, compressive, elongation, stress, and impact properties of a polymer (5). The colorants can act as an interstitial medium and cause microcracks to form in the polymer colorant matrix. This then leads to degradation of the physical properties of the system. Certain chemicals can attack colorants and there can be a loss of physical properties as well as a loss of the chromatic attributes of the colorant. Colorants should always be evaluated in the resin in which they will be used to check for loss of properties that ate needed for the particular appHcations. 

Poly(phenylene sulfide) (PPS) is another semicrystalline polymer used in the composites industry. PPS-based composites are generally processed at 330°C and subsequently cooled rapidly in order to avoid excessive crystallisation and reduced toughness. The superior fire-retardant characteristics of PPS-based composites result in appHcations where fire resistance is an important design consideration. Laminated composites based on this material have shown poor resistance to transverse impact as a result of the poor adhesion of the fibers to the semicrystalline matrix. A PPS material more recently developed by Phillips Petroleum, AVTEL, has improved fiber—matrix interfacial properties, and promises, therefore, an enhanced resistance to transverse impact (see PoLYAffiRS containing sulfur). 

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