Chemical looping comparison

Cho, P., Mattisson, T., and Lyngfelt, A., Comparison of iron-, nickel-, copper- and manganese-based oxygen carriers for chemical-looping combustion, Fuel, 83(9), 1215,2004. 

Wolf, J Anheden, M. and Yan, J. (2005) Comparison of nickel- and iron-based oxygen carriers in chemical looping combustion for CO capture in power generation. Fuel, 84, 993-1006. 

Erlach, B., Schmidt, M. and Tsatsaronis, G. (2011) Comparison of carbon capture IGCC with pre-combustion decarbonisation and with chemical-looping combustion. Energy, 36, 3804-3815. 

Schwebel GL, Leion H, Kruinm W. Comparison of natural ibnenites as oxygen carriers in chemical-looping combustion and influence of water gas shift reaction on gas composition. Chem Eng Res Des 2012 90 1351. 

Saha C, Bhattacharya S. Comparison of CuO and NiO as oxygen carrier in chemical looping combustion of a Victorian brown coal, bit J Hydrog Energy 2011 36 12048. 

Fig. 12. A portion of the 500 MHz DEFT-NOESY spectrum of NPl-ImH, recorded at 30°C in 50 mM phosphate buffer, pH 7.0, D2O. Note the strong EXSY cross peak between the 3-Me signal at 24.9 ppm and a minor 3-Me signal at 26.4 ppm. This is not the other heme orientational isomer, as is evident by comparison of spectrum (a) of Fig. 11. This chemical exchange is also observed for many protein side chains, suggesting fluxionality of some loop, probably the A-B loop that passes close to the heme. In the text, the small peak is defined as species Y, and the large as species X. ...

Chemical modification and structural comparison studies implicate the extended loop and P region between residues 59 and 100 as the main responsible for neurotoxicity (Dufton and Hider 1983 Kini and Evans 1989 Yang 1997). However,... 

Figure 2 Structural comparison of GlyMetThrCysAlaAlaCys motif in a designed 18 residue metallopeptide model (a) and its corresponding loop in MerP protein (h). (Reprinted with permission from Ref. 35. 2000 the American Chemical Society)...

The process of continuous measurement and control is often referred to as a feedback system, and the cycle of measurement, comparison, and control is called a feedback loop. These ideas find wide application in biological and biomedical systems, mechanical systems, and electronics. From measuring and controlling the concentration of manganese in steel to maintaining the proper level of chlorine in a swimming pool, chemical analysis plays a central role in a broad range of systems. 

Figure 21.9 The two control procedures for on-line analysis. Taking a chemical reaction as an example, procedure (a) corresponds to an analyser situated after synthesis (closed loop feedback through comparison with a reference value). Alternatively, procedure (b) corresponds to an up-stream analyser (in an open loop with continuous adjustment of the reagents composition).

The AIChE (American Institute of Chemical Engineers) CCPS (Center for Chemical Process Safety) Process Equipment Reliability Database (PERD) initiative has rigorously identified and documented failure modes for instrument loops, which encompass control, indication, alarm, and automatic protection (Ref. 3). An excerpt from those lists shows a comparison of failure modes applicable to BPCS versus SIS (Figure 2-2). The ability of operations personnel to detect these failure modes is also quite different. 

Blazej, M., Annus, J., andMarkos, J. (2004a), Comparison of gassing-out and pressure-step dynamic methods for kja measurement in an airlift reactor with internal loop, Chemical Engineering Research and Design, 82(10) 1375-1382. 

The intrachain disulfide loops in each of the H chains are similar in their linear disposition to those in L chains. The presence of one disulfide loop for each 110 to 120 amino acid residues provided the first clue suggesting that there are internal homologies of sequence in the polypeptide chain (22). This was further demonstrated by a comparison of partial sequences in the two halves of the Fc fragment of rabbit IgG (61,71) the Fc fragment comprises two domains (Ch2 and Ch3). The degree of sequence homology between these domains is approximately 30%. In addition, there are many positions in which side chains with similar chemical properties (e.g., isoleucine and valine) are present in the two segments. 

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