Loads 468 INDEX

Welding loads and load wear index at 5 wt% concentration (as the extreme pressure performances) are improved compared to those of the original non-phosphosulfurized substrate (Delfort et al., 1998). The welding load (daN), wear load index (daN) and wear scar diameters (mm) under a load 60 daN behavior are... 

Figure 6-3 Classification of Pollution Load Index (PLI) After...

Systematic data on the relation between chemical structure or reactivity of chlorine compounds and lubricant additive performance are sparse. Table 11-11 gives some four-ball test data obtained by Mould, Silver and Syrett [35], with the additives listed in order of increasing effectiveness in terms of the wear/load index. The results show numerous departures from expectations based on chemical structure. For example, there is practically as much difference between the wear/load indices for the two primary chlorides, n-hexadecyl (16.2 kg) and n-hexyl (30.4 kg), as for n-hexyl chloride and t-butyl chloride (46.1 kg). A large difference would be expected on the basis of chemical reactivity between the additive effectiveness of primary and tertiary alkyl chlorides, but only a small difference for the two primary aliphatic chlorides. The overall trends are what would be expected in general, primary and aromatic chlorides are less efficacious than secondary chlorides, which in turn... 

Additive Wear/load index, kg (a) Wear scar diameter, mm (b)... 

Forbes and Silver [40] published data directly comparing the alkyl ester tri-n-butyl phosphate and the aryl ester tricresyl phosphate. Table 11-13 shows the details of this comparison as well as wear data for the acid ester di-n-butyl phosphate. The wear/load index and the initial seizure load show substantially no discrimination between tributyl phosphate and tricresyl phosphate and very little advantage of the compounded oil over the base oil. The low-load wear test distinctly shows better performance with tricresyl phosphate. The data for di-n-butyl phosphate are at variance with the hypothesis that hydrolytic degradation to the acid ester is the first step in the antiwear action of neutral phosphate esters. On the other hand, Bieber, Klaus and Tewksbury [41] separated acidic constituents from commercial tricresyl phosphate by preparative chromatography, and on blending these constituents back into the original tricresyl phosphate at various concentrations they observed enhancement of antiwear action in the four-ball test, as shown in Fig. 11-7. It should be noted that Bieber et at. worked with only 0.051% phosphorus in the lubricant, which may explain the sensitivity they observed to acid impurities. 

The work of Forbes and Battersby [46] is an integrated study of the relations among the chemical structures of the dialkyl phosphites, their adsorption on and reaction with iron, and their behavior in four-ball bench testing of lubricant additive effectiveness. The four-ball data in Table 11-17 for solutions of additive in white oil show that both the wear/load index (mean Hertz load) and the initial seizure load are critically responsive to concentration, with a strong effect when the concentration increases from 0.01 to 0.04 molal (0.031% to 0.124% P). The initial seizure load is an uncomplicated criterion with a straightforward interpretation, whereas the wear/load index is contrived, both in concept and performance. The low-load 50 minute wear data show inconsistencies in the influence of additives that have not been explained. 

The influence of the metal ion is seen in Fig. 11-12, which shows low-load four-ball wear data by Allum and Forbes [58]. The results fall into three broad groups low wear levels associated with the ions Zn, Cd" , Ni, Fe " and Ag" " intermediate wear with Pb" , Sn" , and Sb" " " high wear with Bi . Where direct comparison for the effect of alkyl groups are available, they show the ester of the secondary alcohol 4-methylpentanol-2 has a stronger antiwear function than the ester of n-hexanol, except for the nickel salts. No consistent trend on which to base an acceptable explanation for the additive action of these phos-phorodithioates was observed in the data for the wear/load index (mean Hertz load). 

Figure 11-14. Cooperative additive action of t-octyl chloride and di-t-octyl disulfide. Four-ball test 10 seconds at 1750 rpm. Additives in white oil and wear/load index A. 9.1% Di-t-octyl disulfide, 2.08% S 48.0 kg. B. 8.52% t-Octyl chloride, 2.05% Cl 51.9 kg. C. 4.55% Di-t-octyl disulfide + 4.53% t-octyl chloride, 1.06% S, 1.00% Cl 81.0 kg. D. 9.1% Di-t-octyl disulfide + 8.52% t-octyl chloride, 2.1% S, 2.0% Cl 112.1 kg. Data by A. Dorinson [38].

Additive (conc.S or Cl) (a) Wear/load index, kg Intitial seizure load, kg... 

Second, to check the workload manipulation the participants were asked to complete the NASA-Task Load Index (TLX Hart Staveland, 1988). The TLX is a subjective measure of workload composed of six rating scales that address the contributions of various sources of workload. Prinzel et al. (in press) had their participants complete the TLX after each 16-minute period. 

Hart, S. G., Staveland, L. E. (1988). Development of NASA-TLX (Task Load Index) Results of empirical and theoretical research. In P A. Hancock N. Meshkati (Eds.X Human mental workload (pp. 139-183). Amsterdam North-Holland. 

TABLE 14.2 European Tyre and Rim Technical Organization (ETRTO) Load Index Numerical CodeforTire Load-Carrying Capability [European Tyre and Rim Technical Organization, 2004]... 

TABLE II European Tire and Rim Technical Organization ETRTO Load Index Numerical Code for ... 

To achieve reproducible control over the amount of shear stress produced, we have built a mechanical device (Fig. 2A) that eliminates individual operator variability. Using this device, one can clearly demonstrate the relationship between loading efficiency (loading index), number of strokes, and stroke pressure (Fig. 2B). The use of this device to load FDxLys and IgG is illustrated in Fig. 3. We are presently investigating syringe loading as a cell transfection technique (Fig. 3C). 

Rock type Dry density (g/cmh Effective porosity (%) Uniaxial compressive strength (MPa) Point load index (MPa) P-wave velocity (m/s)... 

One of the most common accepted methods of investigating empirical relationships between rock properties such as durability and physical and mechanical properties is simple and multiple regression analyses. In this study, we have used the multiple regression analyses for assessing the samples durabihty using porosity, uniaxial compressive strength, point load index and P-wave... 

Dry Weight Loss, DWL Effective Porosity, n Uniaxial compressive strength, UCS Point load index, IS(50) P-Wave velocity, Vp. 

Figure 4. Measured DWL versus Estimated DWL from Eq. (1) using porosity and Point load index.

The statistical models for estimating the stones durability against salt crystallization using both the porosity and mechanical properties were proposed. These models were developed by multiple regression analysis and the statistically checked. The application of the models is that a physical properties (prosity) and mechanical properties measurement (uniaxial compressive strength, point load index and P-wave velocity) of the stone can used for... 

Anisotropy category Strength index lo Velocity index 1., Point load index 1 ... 

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