Longterm performance

Filter media used in dust-collections systems is prone to damage and abrasive wear. Therefore, regular inspection and replacement is needed to ensure continuous, longterm performance. Any damaged, torn, or improperly sealed bags should be removed and replaced. 

This stability is important to plastics longterm performance. However, for some applications only short-term performance is desired before the product is discarded, as in the fast-food and packaging markets. In such cases it is considered advantageous for discarded plastic to degrade when exposed to microbes. There thus exists a requirement to develop or modify plastics possessing the properties required for their service life, but with the capability of degrading in a timely... 

Regarding longterm performance it is too early to draw any conclusions. ... 

On the other hand, the presence of these esters in the electrolyte solutions raised concern over the longterm performance at room temperatures, because EIS studies indicated that the resistance associated with the SEI film increased at a much higher rate for ester-based electrolytes as compared with the compositions that were merely based on carbonates. The authors attributed this rising cell impedance to the reactivity of these esters toward the electrode active material, which resulted in the continued growth of the SEI film in the long term and suggested that alkyl esters, especially those of acetic acid, might not be appropriate cosolvents for low-temperature application electrolytes. ... 

Longterm Performance of Exterior-Grade Tannin-Bonded Particleboard... 

Sasaki, K. et al., Ultra-low platinum content fuel cell anode electrocatalyst with a longterm performance stability, Electrochim. Acta, 49, 3873, 2004. 

Concrete is a composite material made of aggregates and the reaction product of the cement and the mixing water, i. e. the porous cement paste. The structure and composition of the cement paste determines the durability and the longterm performance of concrete. Concrete is normally reinforced with steel bars. The protection that concrete provides to the embedded steel and, more in general, its ability to withstand various types of degradation, also depends on its structure. This chapter illustrates the properties of the most utiHsed cements and the microstructure of hydrated cement pastes. Properties of concrete and its manufacturing are discussed in Chapter 12. 

Considering static fatigue of plastics, service failures are almost inevitably brittle, whereas failures from short-term tests at higher stresses arc often ductile. Extrapolations from tests giving ductile failures will result in an overestimate of longterm performance. At some point there will be a ductile brittle transition that may be seen as a "knee" in the lifetime curve, beyond which the decline in strength accelerates. The transition is shifted to lower times by... 

Penetration of chlorides from seawater with subsequent corrosion of embedded steel represents a serious problem and threat to the durability and long-term performance of many concrete structures in marine environments. Recent field investigations of relatively new concrete structures in Norwegian harbors have shown that chloride-induced corrosion may occur already after a service period of approximately 10 years [1-2]. In order to obtain a more controlled durability and longterm performance of concrete structures in marine environments, a proper durability design should be carried out [3]. As part of such design, surface hydrophobation of the most exposed parts of the structure may be one of several protective measures that should be considered. 

Schmittinger W and Vahidi A (2008), A review of the main parameters influencing longterm performance and durability of PEM fuel cells , Jowmu/qfFowr Sources, 180,1, 1-14. 

The new approach allows a great nnderstanding of onr nentron shielding longterm performance... 

Effective surface pretreatments are known to improve both the initial and longterm performance of many substrate/adhesive systems. Surface treatments may... 

In current performance assessments, radionuclide retardation in the geosphere is represented as a sorption process. Data acquired within the NSARP are used to support the representation of sorption within assessment models of the longterm performance of the repository. Sorption is generally quantified using a sorption coefficient, which is the ratio of the concentration of radionuclide sorbed on the solid (per unit mass) to the concentration in solution (per unit volume). It is assumed that sorption is linear (i.e. the sorption coefficient is independent of radionuclide concentration) and reversible. The assumption of linearity is considered reasonable for the expected range of concentrations predicted along possible flowpaths from the repository to the... 

Nowell, G. M., Pearson, D. G., Ottley, C. J., Schwieters, J., and DowaU, D., (2003) Longterm performance characteristics of a plasma ionisation multi-coUector mass spectrometer (PIMMS) the ThermoFinnigan Neptune. In Plasma Source Mass Spectrometry (eds G. Holland and S. D. Tanner), Royal Society of Chemistry Cambridge. 

There is some controversy regarding the relative importance of these two mechanisms. Resolving these aspects of the ageing process is not merely of academic interest, it is essential to clarify this question if composites of improved longterm performance are to be developed and used. In particular, should the effort be directed towards improvement of the fibres, or modification of the interface through the matrix composition In this section a critical review of this problem will be presented. 

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