Degraded functionality/performance

Too much, and the cell will flood too little, and the cell membrane will dehydrate. Both will severely degrade cell performance. The proper balance is achieved only by considering water production, evaporation, and humidification levels of the reactant gases. Achieving the proper level of humidification is also important. With too much humidification, the reactant gases will be diluted with a corresponding drop in performance. The required humidification level is a complex function of the cell temperature, pressure, reactant feed rates, and current density. Optimum PEFC performance is achieved with a fully saturated, yet unflooded membrane (47). 

When reactor capacity is limited by heat removal, an often-recommended control structure is to run with maximum coolant flow and manipulate feed flowrate to control reactor temperature (Tr F0 control). This control scheme has the potential to achieve the highest possible production rate. However, if the feed temperature is lower than the reactor temperature, the transfer function between temperature and feed flowrate contains a positive zero, which degrades dynamic performance, as we demonstrate quantitatively in this section. The choice of a control structure for this process presents an example of the often encountered conflict between steady-state economics and dynamic controllability. 

Stress degrades the performance of tasks involving creative thought. If a human being is to contribute effectively to a partnership with a computer, he or she should be allowed to function without handicaps. Therefore the causes of stress should be identified and, as far as possible, removed. Effective partnership with a supercomputer will require even higher levels of intellectual performance from the human. Therefore it will more-imperatively require the reduction of stress. 

The degradation functions quantitatively link skill performance to the level of a stressor. The degradation functions can be developed from any data source, including standard test batteries or actual human tasks. Through statistical analysis, one can build skill-degradation functions for each taxon. These functions map the performance decrement expected on a skill based on the parameters of the... 

Figure 17 An Example of the Performance Degradation Functions Associated with each of the Human Skills from the Taxonomy.

In building the task network model, one can build functions to degrade a specific task s performance through an arithmetic weighting of sldll-degradation multipliers that are derived from the degradation functions. For example, if the fatigue parameter was time since sleep and the value of that parameter was 36 hours since sleep, the task time performance multipliers would be as follows in the example above ... 

Inverted Device Structures The conventional device structure for PSCs is indium tin oxide (ITO)/PEDOT PSS/polymer blend/Al, where a conductive high-work-function PEDOTPSS layer is used for anode contact, and a low-work-function metal as the cathode. Both the PEDOTPSS layer and the low-work-function metal cathode can cause the degradation of PSCs [110-112]. The acidic PEDOTPSS was reported to etch the ITO and cause interface instability through indium diffusion into the polymer active layer. Low-work-fiinction metals, such as calcium and aluminum, are easily oxidized when exposed to air, increasing the series resistance at the metal/BHJ interface and degrading device performance. 

The performance of the human system is only at an optimum within certain environmental limits. As part of the price of its sensitivity and flexibility the human system is susceptible to the influence of a very large range of factors which can affect its performance. Unlike machines, human beings show a slow and often subtle degradation of performance over a wide range of environmental conditions, but arrive at a total breakdown only comparatively rarely. This means that individuals can maintain some sort of functioning long after they have passed the peak of their performance, but it also blurs the point at which they should stop in order to avoid errors. 

It is carried out after the design is completed, before released for production. It mainly focuses on potential failure associated with proposed function of the application. It also focuses on design deficiencies, possible failures, and degradation of performance of the product. 

The signal leakage through inadequate isolation devices to safely related circuitry could damage or seriously degrade the performance of Class IE components. In other causes, electrically-generated noise on the circuit may cause the isolation device to give a false output. All these may cause the functional failure of safety systems. 

---