Gas chromatograph/isotope dilution mass spectrometric analysis of airborne benzo

A critical evaluation has been made of the gas chromatography/isotope dilution mass spectrometry (GC/IDMS) analysis of airborne benzo[a]pyrene (B[a]p) using 2H-(deuterium, D) and 13C-labeled benzo[a]pyrene and a low resolution mass spectrometer. Laboratory quality control and field samples were used to determine the suitability of these two isotopically labeled B[a]p as surrogates for GC/IDMS B[a]p analysis. With method spike QC samples, recovery of the B[a]p was compared with the recoveries of D- and 13C-labeled B[a]p to validate the assumption that these two isotopically labeled B[a]p analogs could be used as method surrogates for IDMS B[a]p analyses. Two collocated Anderson Hi-Vol samplers were used to carry out a field study in which total B[a]p loadings from one sampler were correlated to the second sampler, before and after correcting the total B[a]p loadings against the recovery of the D- and 13C-labeled B[a]p. It is shown that a low-resolution mass spectrometer can be used in GC/IDMS B[a]p analysis to achieve results of high precision and accuracy. Depending on data quality objectives, D-labeled B[a]p could be used for IDMS B[a]p analysis, but is not recommended.     

Elucidating the Effect of Planar Graphitic Layers and Cylindrical Pores on the Storage and Diffusion of Li,Na, and K in Carbon Materials

Hard carbons are among the most promising materials for alkali‐ion metal anodes. These materials have a highly complex structure and understanding the metal storage and migration within these structures is of utmost importance for the development of next‐generation battery technologies. The effect of different carbon structural motifs on Li, Na, and K storage and diffusion are probed using density functional theory based on experimental characterizations of hard carbon samples. Two carbon structural models—the planar graphitic layer model and the cylindrical pore model—are constructed guided by small‐angle X‐ray scattering and transmission electron microscopy characterization. The planar graphitic layers with interlayer distance <6.5 Å are beneficial for metal storage, but do not have significant contribution to rapid metal diffusion. Fast diffusion is shown to take place in planar graphitic layers with interlayer distance >6.5 Å, when the graphitic layer separation becomes so wide that there is negligible interaction between the two graphitic layers. The cylindrical pore model, reflecting the curved morphology, does not increase metal storage, but significantly lowers the metal migration barriers. Hence, the curved carbon morphologies are shown to have great importance for battery cycling. These findings provide an atomic‐scale picture of the metal storage and diffusion in these materials.     

Challenges and implemented technologies used in autonomous drone racing

Intelligent Service Robotics - Autonomous drone racing (ADR) is a challenge for autonomous drones to navigate a cluttered indoor environment without relying on any external sensing in which all the...     

CH4/CD4 isotope effects in the carbon dioxide reforming of methane to syngas over SiO2-supported nickel catalysts

By performing the CH₄ + CO₂ and CD₄ + CO₂ reactions alternately over SiO₂-supported nickel catalysts in a pulse micro-reactor, normal deuterium isotope effects on both the methane conversion reaction and on the CO formation reaction have been observed in the process of CO₂ reforming of methane. Based on the observed CH₄/CD₄ isotope effects, the pathways for the formation of CO are discussed.     

Sol–Gel-Generated La2NiO4 for CH4/CO2 Reforming

A stable La₂NiO₄ catalyst active in CH₄/CO₂ reforming has been prepared by a sol–gel method. The catalyst was characterized by techniques such as XRD, BET, TPR and TG/DTG. The results show that the conversions of CH₄ and CO₂ in CH₄/CO₂ reforming over this catalyst are significantly higher than those over a Ni/La₂O₃ catalyst prepared by wet impregnation and those over a La₂NiO₄/-Al₂O₃ catalyst. The TG/DTG outcome confirmed that the amount of carbon deposition observed in the former case was less than that observed in the latter two cases, a phenomenon attributable to the uniform dispersion of nanoscale Ni particles in the sol–gel-generated La₂NiO₄ catalyst.     

Molybdenum nitride for the direct decomposition of NO

The physico-chemical properties of passivated -Mo₂N have been investigated. The material showed high activities for NO direct decomposition: nearly 100% NO conversion and 95% N₂ selectivity were achieved at 450C. The amount of O₂ taken up by -Mo₂N increased with temperature rise and reached 3133.9 molg^–1 at 450C; we conclude that there formation of Mo₂O_xN_y occurred. This oxygen-saturated -Mo₂N material was catalytically active: NO conversion and N₂ selectivity were 89 and 92% at 450C. We found that by means of H₂ reduction at 450C, Mo₂O_xN_y could be reduced back to -Mo₂N and the oxidation/reduction cycle is repeatable; such a behaviour and the high oxygen capacity (3133.9 molg^–1) of -Mo₂N suggest that -Mo₂N is a promising catalytic material for automobile exhaust purification.     

The effect of added fullness and ventilation holes in T-shirt design on thermal comfort

This paper reports on an experimental investigation on the effect of added fullness and ventilation holes in T-shirt design on clothing comfort measured in terms of thermal insulation and moisture vapour resistance. Four T-shirts in four different sizes (S, M, L, XL) were cut under the traditional sizing method while another (F-1) was cut with specially added fullness to create a 'flared' drape. A thermal manikin 'Walter' was used to measure the thermal insulation and moisture vapour resistance of the T-shirts in a chamber with controlled temperature, relative humidity and air velocity. The tests included four conditions: manikin standing still in the no-wind and windy conditions and walking in the no-wind and windy condition. It was found that adding fullness in the T-shirt design (F-1) to create the 'flared' drape can significantly reduce the T-shirt's thermal insulation and moisture vapour resistance under walking or windy conditions. Heat and moisture transmission through the T-shirt can be further enhanced by creating small apertures on the front and back of the T-shirt with specially added fullness. STATEMENT OF RELEVANCE: The thermal comfort of the human body is one of the key issues in the study of ergonomics. When doing exercise, a human body will generate heat, which will eventually result in sweating. If heat and moisture are not released effectively from the body, heat stress may occur and the person's performance will be negatively affected. Therefore, contemporary athletic T-shirts are designed to improve the heat and moisture transfer from the wearer. Through special cutting, such athletic T-shirts can be designed to improve the ventilation of the wearer.     

Supply chain workflow modelling using XML-formatted modular petri nets

This paper presents a modelling methodology of a workflow system of operations in a supply chain (SC) aimed to improve, from the traditional method, the consistency and integrity of the workflow data being exchanged amongst business partners. In this research, an XML-supported modular petri net-based modelling technique is adopted for the representation of the local and global workflow of "practitioners" in a SC. After constructing a petri net, the model of workflow systems can be constructed, understood and analysed more easily. A modular compositional modelling method is adopted to fulfill the particular functional requirements of a collaborative modelling of dispersed business partners in an up-to-date globalised SC environment. Finally, the use of a widely adopted XML schema for data representation and standard interface and interconnection mechanisms development in a workflow model can further improve the model's overall flexibility and integrity.