CH3-Terminated Carbon Chains in the GOTHAM Survey of TMC-1: Evidence of Interstellar CH3C7N

We report a systematic study of all known methyl carbon chains toward TMC-1 using the second data release of the GOTHAM survey, as well as a search for larger species. Using Markov Chain Monte Carlo simulations and spectral line stacking of over 30 rotational transitions, we report statistically significant emission from methylcyanotriacetylene (CH3C7N) at a confidence level of 4.6σ, and use it to derive a column density of ∼1011 cm−2. We also searched for the related species, methyltetraacetylene (CH3C8H), and place upper limits on the column density of this molecule. By carrying out the above statistical analyses for all other previously detected methyl-terminated carbon chains that have emission lines in our survey, we assess the abundances, excitation conditions, and formation chemistry of methylpolyynes (CH3C2n H) and methylcyanopolyynes (CH3C2n-1N) in TMC-1, and compare those with predictions from a chemical model. Based on our observed trends in column density and relative populations of the A and E nuclear spin isomers, we find that the methylpolyyne and methylcyanopolyyne families exhibit stark differences from one another, pointing to separate interstellar formation pathways, which is confirmed through gas–grain chemical modeling with nautilus.

Functionalization and Hydrogenation of Carbon Chains Derived from CO

Selective reactions that combine H2, CO and organic electrophiles (aldehyde, ketones, isocyanide) to form hydrogenated C3 and C4 carbon chains are reported. These reactions proceed by CO homologation mediated by [W(CO)6] and an aluminum(I) reductant, followed by functionalization and hydrogenation of the chain ends. A combination of kinetics (rates, KIEs) and DFT calculations has been used to gain insight into a key step which involves hydrogenation of a metallocarbene intermediate. These findings expand the extremely small scope of systems that combine H2 and CO to make well-defined products with complete control over chain length and functionality.

Influence Mechanism of Magnetized Modified Kerosene on Flotation Behavior of Molybdenite

The effects and mechanism of magnetized kerosene on the flotation behaviors of molybdenite were studied by micro-flotation, ultraviolet spectrum, infrared spectrum, surface tension, and liquid viscosity. According to the results of micro-flotation, magnetized kerosene improved the flotation recovery of molybdenite, and the improvements were more obvious with smaller molybdenite particles. Spectral analysis showed that the magnetization did not change the chemical composition of kerosene, but transformed the linear aliphatic hydrocarbons in kerosene into linear isomers and reduced the lengths of the carbon chains. Moreover, the magnetization reduced the viscosity of kerosene and oil/water interfacial tension, and improved the dispersion of kerosene in the pulp. The external magnetic field transformed the disorder of the additional magnetic moment in the kerosene molecules into order, and reduced the compactness of the kerosene molecules. The experimental results provided a theoretical explanation for the role of magnetization in mineral flotation.

Spin thermoelectric effects of new-style one-dimensional carbon-based nanomaterials

Based on first-principles methods, the authors of this paper investigate spin thermoelectric effects of one-dimensional spin-based devices consisting of zigzag-edged graphene nanoribbons (ZGNRs), carbon chains and graphene nanoflake. It is found that the spin-down transmission function is suppressed to zero, while the spin-up transmission function is about 0.25. Therefore, an ideal half-metallic property is achieved. In addition, the phonon thermal conductance is obviously smaller than the electronic thermal conductance. Meantime, the spin Seebeck effects are obviously enhanced at the low-temperature regime (about 80K), resulting in the fact that spin thermoelectric figure of merit can reach about 40. Moreover, the spin thermoelectric figure of merit is always larger than the corresponding charge thermoelectric figure of merit. Therefore, the study shows that they can be used to prepare the ideal thermospin devices.

Biosurfactant and chemical surfactant effectiveness test for oil spills treatment in a saline environment

Toxic and persistent nature of hydrocarbon and its products make it a significant concern for treating oil spills. In addition, hydrocarbons such as crude oil have long and complex carbon chains, making them challenging to remove directly. Emergency response for oil spills generally conducted by spraying dispersant agent into spillage surface. However, the use of chemical dispersants is reported to have a negative impact on the environment. Therefore, an environmentally friendly method for treating oil spills, utilizing biological agents such as biosurfactant or bioemulsifier, is needed. This research focuses on performance tests of more environmentally friendly surfactants as substitute for chemical surfactant which causes toxic effect when used. Surfactant performance was evaluated through three indicators: emulsifying index, dispersion effectiveness, and germination index (G.I.). Performance test was carried out for three types of surfactants: sophorolipid biosurfactant, methyl ester sulfonate (MES), and tween-80. Dispersion effectiveness test showed sophorolipid, MES, and tween-80 enhanced hydrocarbons dispersion in saline water up to 26.59, 38.65, and 48.19%, respectively. Germination index test showed the average G.I. for oil dispersed by sophorolipid, MES, and tween-80 are 153.16%, 143.94%, and 6.69 %, respectively. Research result suggests sophorolipid and MES have the properties to enhance oil dispersion under-examined laboratory conditions.

Development of nano-activated carbon and apply it for dyes removal from water

The present study investigates the production of nano-activated carbon from banana peels mixed with nylon 6.6 and polyethene. The carbonization process was carried out by mixing accurate percentages of the banana peels with different ratios of nylon 66 and a suitable amount of potassium hydroxide. The fusion carbonization, without solvents, was used in this paper to decompose the nylon mixture, releasing amino and carboxylate roots that can easily react with the carbon chains. The prepared nano-activated carbon was characterized using different technologies, including SEM, AFM, FT-IR, and EDX technologies. The results showed the produced carbon has spherical particles with a pore size of 1.21 nm and a surface area of 1,071.7 m2/gm. Additionally, it was noticed, from the FT-IR spectrum, the prepared carbon does not contain any active groups, which means it is an inert material. X-ray analysis showed the new carbon is made from carbon (78.57%) and oxygen (21.43%). After optimizing the wavelength, the prepared carbon was used to adsorb methylene blue and Eirochrom black T dyes from solutions. The results showed the best equilibrium time, dose of carbon and concentration of dyes was 40–50 minutes, 0.04 g and 20 ppm, respectively.