Experimental and modeling studies of formation of products of incomplete combustion and chlorocarbon incineration

The two-stage combustor facility was used to investigate the process of chlorocarbon incineration and formation of products of incomplete combustion. For this purpose methylene chloride was used as a chlorine-containing compound. The propose of this research was to obtain a better understanding of the incineration process of chlorocarbons, such as methylene chloride, especially regarding its destruction efficiency and formation of products of incomplete combustion. For measuring near-real time very low concentrations of benzene and methylene chloride, on-line microtrap gas chromatography system was used. The experimental system was validated using a known combustion reaction mechanism from literature. Modeling of combustion process has shown different pathways of benzene formation for first (perfectly stirred) and the second (plug flow) zones of the combustor with residence time 0.007 and 0.029 sec respectively. Destruction efficiency of methylene chloride was investigated under different equivalence ratio and inlet concentration. Influence of methylene chloride on formation of products of incomplete combustion such as methane, ethylene, ethane, and acetylene was investigated. Combustion process was simulated using a reactor model and the reaction mechanism. Rate-of production analysis based on modeling results showed that there are different pathways for destruction of methylene chloride under fuel-lean and fuel-rich conditions. As shown by experimental results, destruction efficiency is lower at its lower concentrations. Simulations of experimental results on destruction of methylene chloride, methyl chloride, and benzene, has shown that significance of various radicals and destruction channels varies with combustion conditions and concentrations of organics, and that atoms and fragments of destroyed molecules play important role in further destruction of parent species. In order to describe the effect of additional radicals and fragments on the total rate of destruction additional rate function was derived and calculated for methylene chloride combustion cases

A multipronged approach unravels unprecedented protein-protein interactions in the human 2-oxoglutarate dehydrogenase multienzyme complex

The human 2-oxoglutaric acid dehydrogenase complex (hOGDHc) plays a pivotal role in the tricarboxylic acid (TCA) cycle, and its diminished activity is associated with neurodegenerative diseases. The hOGDHc comprises three components, hE1o, hE2o, and hE3, and we recently reported functionally active E1o and E2o components, enabling studies on their assembly. No atomic-resolution structure for the hE2o component is currently available, so here we first studied the interactions in the binary subcomplexes (hE1o-hE2o, hE1o-hE3, and hE2o-hE3) to gain insight into the strength of their interactions and to identify the interaction loci in them. We carried out multiple physico-chemical studies, including fluorescence, hydrogen-deuterium exchange MS (HDX-MS), and chemical cross-linking MS (CL-MS). Our fluorescence studies suggested a strong interaction for the hE1o-hE2o subcomplex, but a much weaker interaction in the hE1o-hE3 subcomplex, and failed to identify any interaction in the hE2o-hE3 subcomplex. The HDX-MS studies gave evidence for interactions in the hE1o-hE2o and hE1o-hE3 subcomplexes comprising full-length components, identifying: (i) the N-terminal region of hE1o, in particular the two peptides 18YVEEM22 and 27ENPKSVHKSWDIF39 as constituting the binding region responsible for the assembly of the hE1o with both the hE2o and hE3 components into hOGDHc, an hE1 region absent in available X-ray structures; and (ii) a novel hE2o region comprising residues from both a linker region and from the catalytic domain as being a critical region interacting with hE1o. The CL-MS identified the loci in the hE1o and hE2o components interacting with each other

Thermal Conductivity of Carbon Nanotubes and their Polymer Nanocomposites: A Review

Thermally conductive polymer composites offer new possibilities for replacing metal parts in several applications, including power electronics, electric motors and generators, heat exchangers, etc., thanks to the polymer advantages such as light weight, corrosion resistance and ease of processing. Current interest to improve the thermal conductivity of polymers is focused on the selective addition of nanofillers with high thermal conductivity. Unusually high thermal conductivity makes carbon nanotube (CNT) the best promising candidate material for thermally conductive composites. However, the thermal conductivities of polymer/CNT nanocomposites are relatively low compared with expectations from the intrinsic thermal conductivity of CNTs. The challenge primarily comes from the large interfacial thermal resistance between the CNT and the surrounding polymer matrix, which hinders the transfer of phonon dominating heat conduction in polymer and CNT. This article reviews the status of worldwide research in the thermal conductivity of CNTs and their polymer nanocomposites. The dependence of thermal conductivity of nanotubes on the atomic structure, the tube size, the morphology, the defect and the purification is reviewed. The roles of particle/polymer and particle/particle interfaces on the thermal conductivity of polymer/CNT nanocomposites are discussed in detail, as well as the relationship between the thermal conductivity and the micro- and nano-structure of the composite