Carbon monoxide radiation in an equilibrium plasma torch facility

International audienceWe present spectrally resolved measurements of CO 4th positive radiation down to 170 nm under equilibrium conditions. The emission is calibrated in absolute intensity by using an argon discharge calibrated to NIST standards. The measurements were undertaken to validate radiation models available in the literature. NASA EAST measurements had noted a discrepancy between radiation model predictions and their shock tube measurements. Our goal was to perform these measurements under equilibrium conditions and compare against model predictions. To that end, we selected several datasets for the electronic transition moment available in the literature. These were used to calculate state-specific Einstein coefficients for use with the radiation code SPECAIR. Three datasets were tested and two were found to give good agreement with the experimental results

Experimental analysis of the interaction of carbon and silicon ablation products with expanding hypersonic flows

Thermal protection is required for vehicles entering planetary atmospheres to protect against the severe heating loads experienced. Characterization of candidate materials is often done utilizing plasma or arc-jet facilities, which provide steady-state testing of the thermal environments experienced during hypersonic flight, but do not correctly simulate hypersonic flowfields. Conversely, impulse facilities can reproduce flight velocities and enthalpies but have extremely short test times, prohibiting testing of thermal response. To better understand how these materials interact with hypersonic flows, experiments were conducted at the X2 expansion tunnel at the University of Queensland. Preheated strips of carbon-carbon and silicon carbide-coated carbon-carbon were mounted in a two-dimensional compression wedge and tested in Earth entry flow, marking the first time silicon carbide has been investigated in this facility. Calibrated spectral measurements were obtained in the near-stagnation and expansion regions for surface temperatures from 1900 K to 2600 K. Cyanogen emissions dominated while atomic silicon and dicarbon were also observed. Emissions for both materials displayed a similar increase near the wall, while emissions for silicon carbide-coated samples displayed a distinct rise downstream of the shock, which suggests a higher concentration of ablative species resulting from a higher ablation rate

Perfumed the axe that laid it low: The endangerment of sandalwood in southern India

Between 1950 and 1970, on average over 480,000 Indian sandalwood (Santalum album) trees were harvested annually in the state of Karnataka in southern India. Then, in 1974, it was suddenly discovered that there were only approximately 350,000 standing trees left in the entire state. Overnight, India’s sandalwood industry ground to a halt. The species was on the brink of extinction. Harvesting and trade in Indian sandalwood, long considered the most precious wood in the world, was ineffectively banned. Smugglers could now make more money by felling sandal trees than by poaching elephants for ivory. This article uses the history of sandalwood to assess claims about the nature and impact of colonial and postcolonial forestry, arguing that at least when it came to Indian sandalwood, though European foresters did overexploit the species and also failed to conserve it, the real watershed moment for the species came not during the colonial period but rather in the independence period when industrialisation led to a major endangerment crisis for the tree