Average cycling lifetime

When manufacturers publish the cycling lifetimes of their products (usually determined by measuring the degradation of capacity), they specify the cycling conditions apphed at 25 C (unless otherwise stated) and subjected to 1,000 cycles. A few examples are given in Table 6.14. 

C-LMO KOKAM polymer (C during discharge / C during charge) 100% DOD 12.5% capacity lost 80% DOD 2.5% capacity lost 20% DOD 1.7% capacity lost 

C-NMC SAMSUNG (0.5 C during charge / 1 C during discharge) 1000 cycles 22.2 % capacity lost 

The temperature also influences the number of cycles delivered. We have recorded impacts on lifetime when the temperature exceeds 40-45°C, but these impacts are more or less marked depending on the technology and the manufacturer (Table 6.15). 

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Batscap claims an average cycling lifetime of 1000 cycles (lifetime of 200000 km with an autonomy of over 200 km for a complete charge). 

Figure 15 shows how the average fatigue lifetime of PS depends on frequency for two different stress amplitudes. The variation appears to be a linear one on this log-log plot, with the number of cycles to fracture increasing with increase of frequency, and at essentially the same rate for both stress amplitudes. For the rubber modified HIPS the fatigue endurance is plotted as a function of frequency in Fig. 16. Here too the lifetime increases with increase of test frequency and again the variation is a linear one on a log-lot plot. The slope of these curves is also essentially independent of stress...

It can be seen that the asymptotic availability is given by the average component lifetime divided by a cycle consisting of the sum of the average lifetime... 

The field of translation initiation has focused on the initial round ofribosomal subunit recruitment to an mRNA. Presumably, these events are mirrored in the subsequent rounds of initiation necessary for polyribosome formation. Importantly, because mRNAs are typically present in large polyribosomes (averaging 9-13 ribosomes per mRNA), the initiation events that govern ribosome recruitment to preexisting polyribosomes constitute the majority of translation initiation cycles occurring in an mRNA s lifetime. Whether or not these initiation events mimic the first round of initiation is not yet known. Since eukaryotic cells divide ribosomes between two subcellular compartments, the cytosol and ER membrane, it is also important to know if the mechanism of translation initiation on ER-bound ribosomes is similar to that occurring on soluble ribosomes and, importantly, whether ER-bound ribosomes can direcdy (re) initiate translation on bound polyribosmes. 

To optimize resolution in lifetime-based assays, a comparison of relative estimates is always favorable. If the FLIM experiment is carried out in an environment where temperature cannot be tightly controlled, it is also convenient to cycle between different samples during the same experimental session, in order to average out thermal and other instrumental drifts. When applicable, this practice may be useful to suppress any nonrandom variation in the detection. 

Reaction 2-6 is sufficiently fast to be important in the atmosphere. For a carbon monoxide concentration of 5 ppm, the average lifetime of a hydroxyl radical is about 0.01 s (see Reaction 2-6 other reactions may decrease the lifetime even further). Reaction 2-7 is a three-body recombination and is known to be fast at atmospheric pressures. The rate constant for Reaction 2-8 is not well established, although several experimental studies support its occurrence. On the basis of the most recently reported value for the rate constant of Reaction 2-8, which is an indirect determination, the average lifetime of a hydroperoxy radical is about 2 s for a nitric oxide concentration of 0.05 ppm. Reaction 2-8 is the pivotal reaction for this cycle, and it deserves more direct experimental study. 

To achieve a fuel management scheme with the lowest fuel cycle cost consistent with the current thermal and material performance limits, the following parameters are selected (l)a fuel cycle incorporating uranium/thorium (2) a fuel lifetime of four years (3) an average power density of 8.4 W/cm3 and (4) a refueling frequency of once a year. 

We shall also estimate the numbers m.uh and mrot of the librational and rotational cycles performed on average by a librating or a rotating dipole during the lifetime t. 

The hydrogen bonds in liquid water have an average lifetime of less than 10"10 second as measured by dielectric relaxation times (4). But the hydrogen bonds between water and a polymer could exist for longer than 10"7 seconds. Such a structure would appear permanent at the frequencies used in the ultrasonic impedometer (107 cycles/sec. range), and should demonstrate a measurable shear stiffness at these frequencies. 

The average lifetimes of dust grains in the ISM of about 0.5 Gyr have to be compared with a turnaround time of about 2.5 Gyr for the matter cycle between stars and the ISM, which would result in a small depletion S 0.8 of the refractory elements in the ISM into dust, if depletion of the refractory elements in the returned mass from stars was strong and if no accretion of refractory elements onto dust occurred in the ISM. This clearly contradicts the high observed depletion in the ISM. Hence, most of the interstellar dust is formed in the ISM and is not stardust (Draine 1995 Zhukovska et al. 2008). The most likely place for dust growth in the ISM is in the dense molecular clouds (Draine 1990), but the processes responsible for growth are presently unknown. 

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