Power densities maximum

Other possible applications of smart elastomers are in the area of polymer engine which can produce maximum power density (4 W/g) and output both in terms of electrical and mechanical power without any noise. These features are superior compared to conventional electrical generator, fuel cell, and conventional IC engine. Many DoD applications (e.g., robotics, MAV) require both mechanical and electrical (hybrid) power, and polymer engine can eliminate entire transducer steps and can also save engine parts, weight, and is more efficient. 

In contrast to this, the enzyme resin is stressed less by gas sparging than by stirring (see Fig. 18 and 20). The same activity losses were observed first with 1 to 8 times greater specific adiabatic compression power Pj/ V than the maximum power density necessary for stirring. As in the case of the smooth disc, the effects of power input are only weak. The type of gas sparger and therefore the gas exit velocity are of no recognisable importance. The behaviour of the enzyme resin particles is thus completely different from that of the clay min-eral/polymer floes and the oil/water/surfactant droplet system, which are particularly intensively stressed by gas sparging. 

As can be seen from Eq. (5), the maximum power density delivered to the load is ... 

The suitability of lanthanum nickelate as an SOFC cathode has been examined by Virkar s group [138], They showed that LN performed poorly as a single-phase cathode in an anode-supported YSZ cell. However, with an SDC/LN composite interlayer the performance of the LN cathode increased substantially and the maximum power density of the cell with a YSZ thin electrolyte (-8 pm) was -2.2 Wear2 at 800°C, considerably higher than 0.3 to 0.4 Wcm-2 of similar cells with only LN or SDC interlayer. The results are significant as it shows that the composite MIEC cathodes perform much better than single-phase MIEC in the case of LN despite its mixed ionic and electronic conductivity. 

For the probe system, whatever design of horn is used, a large maximum power density can be achieved at the radiating tip. This can be of the order several hundred W cm . The working frequencies are normally of the order 20 - 40 kHz. A number of probe devices are commercially available and, up to a few years ago (before the advent of sonochemistry) were referred to as cell disrupters. The majority operate at 20 kHz and utilise a wide range of different metal probes. The advantages of the probe method of energy input are threefold ... 

Figure 22. Maximum power density for a Cu-Ce02-YSZ anode SOFC as a function of the conversion of fuel entering the anode compartment. The data for preoxidation of 77-butane by ceria ( ) and 1 wt % Pd-ceria (a) are shown. The maximum power densities obtained when /7-butane was diluted with He to a concentration equivalent to that obtained by total oxidation are shown by (O). (Reprinted with permission from ref 177. Copyright 2003 The Electrochemical Society, Inc.)...

With the best electrocatalyst, that is, Pt-Sn (90 10)/XC72, the effect of temperature on the cell voltage E and power density P versus current density j characteristics is shovm in Figure 1.14. It appears clearly that increasing the temperature greatly increases the performance of the cell, from a maximum power density close to 5 mWcm at 50 ° C to 25 mW cm at 110 ° C, that is, five times higher. 

The highest maximum potver density examined at 30 °C tvas produced by the catalyst supported on P-CNF. Hotvever, the catalyst supported on thick H-CNF showed the highest maximum power density at 60 and 90 °C. The single cell... 

Table 3.1 Maximum power densities in single cell and average particle sizes of catalysts calculated by XRD.

CNF Average diameter (nm) BET surface area (m g ) Maximum power density (mW cm ) Particle size (nm)... 

Since high current density at the maximum power density and the cost of the noble metals are important parameters for the commercialization of DMECs, H-CNE-supported Pt-Ru alloys maybe classified among the most efficient and cost-effective anode catalysts. It is also worth mentioning that the CNF-supported catalysts feature superior catalytic activity at the high temperatures where the mass transfer of methanol and oxygen is more favorable due to the fibrous network of CNEs. 

The 1-Vcurves from single cell tests with the Pt-Ru 40 wt% catalysts supported on thick H-CNE and nanotunneled H-CNE (Pt 1.33, Ru 0.67 and CNE 3mgcm ) and with the Pt-Ru 60 wt% E-TEK catalyst (Pt 2, Ru 1 and C 2 mg cm ) (5 mg slurry hand-brushed on carbon paper) are shown in Eigure 3.6, and their maximum power densities are listed in Table 3.2. The maximum power densities produced by the E-TEK catalyst at 30 and 90 ° C were 41 and 140 mWcm , respectively. The maximum... 

Table 3.2 Maximum power densities in singie ceii and average particie sizes, caicuiated byXRD, of cataiysts supported on thick H-CNF, nanotunneied H-CNF and E-TEK.

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