Terpenes such as d-limonene, α-pinene and p-cymene are considered green solvents that have no harmful effects on human health and the environment. These solvents represent promising alternatives for many recently-classified harmful solvents such as n-hexane, the typical solvent used for the extraction of vegetable oils. Although terpenes show high solvation power for the different oil constituents, their recovery by conventional evaporation stands as a barrier for their large-scale utilisation as they have significant higher boiling points than n-hexane. In this work, the transport of terpenes through a composite PDMS/PAN membrane is investigated at different experimental conditions. A nonlinear increase in the solvent flux was observed with increasing transmembrane pressure which could be explained by the solution-diffusion model in a highly swollen membrane. The highest fluxes were observed with d-limonene followed by p-cymene then α-pinene. The sorption equilibria and diffusion coefficient of the terpenes in free-standing PDMS films were also studied and this data used to successfully model the permeation data. The performance of the PDMS/PAN membranes was stable after storage in the solvents for one year. The results obtained from this study indicate potential utilisation of solvent resistant nanofiltration for the recovery of terpenes with minimal energy consumption.

The presence of condensable aromatic hydrocarbons in raw natural gas streams creates a significant challenge for acid gas removal through membrane separation. In this work, the impact of toluene and xylene on the gas separation performance of cellulose triacetate (CTA) membranes was studied. When operating at low CO 2 partial pressures (0.75 Bar), both toluene and xylene reduced the permeation of CO 2 at low vapour activities, due to competitive sorption and the pore-filling or anti-plasticisation effect. Conversely, at vapour activities greater than 0.5, toluene caused membrane plasticisation, possibly coupled with a decrease in crystallinity. On the other hand, when operating at 7.5 Bar CO 2 pressure, plasticisation was observed at a lower vapour activity of 0.3 for both toluene and xylene. This study shows that two penetrants can influence the plasticisation behaviour in a cooperative manner that cannot be described by a simple additive model. The study also shows that the permeabilities of toluene and xylene are comparable with that of methane.

Bio-derived solvents such as ρ-cymene, d-limonene and α-pinene represent feasible alternatives to nhexane for the extraction of vegetable oils. However, the large-scale utilization of these solvents is still limited mainly owing to their high boiling points and latent heats of vaporization. In this work, the performance of composite polydimethylsiloxane/polyacrylonitrile (PDMS/PAN) organic solvent nanofiltration membranes in the recovery of these solvents from their binary mixtures with canola oil is investigated. The sorption isotherms of the mixtures were first studied using free-standing PDMS films and the multicomponent Flory-Huggins model used to determine the resulting interaction parameters. The partial solvent uptake decreased with increasing oil concentration in the mixture. On the other hand, the partial oil uptake in the solvent mixture was higher than that of the pure oil which was attributed to the swelling effects induced by solvents. The effects of feed concentration (10-30 wt. % oil), feed temperature (25-40 °C), transmembrane pressure (5-30 bar), and cross-flow velocity (18-52 cm s -1 ) on the membrane performance were then studied in a cross-flow membrane setup.Maxwell-Stefan formulations were combined with the ternary Flory-Huggins solubility model to successfully describe these flux data.

Vegetable oils derived from rapeseed and its genetic variant canola, are conventionally extracted from oilseeds by means of an organic solvent, typically hexane. Concerns regarding the toxicity of hexane have meant safer and more environmentally friendly solvents such as terpenes are becoming attractive. In this research, the degumming of canola oil/terpene mixtures using ultrafiltration is considered as a critical step in such an extraction process. Polysulfone (PSF) and polyethersulfone (PES) membranes were found to be ineffective in this application, as the oil appeared to cause swelling of the membrane structure. This meant that the original flux could not be restored after cleaning. Conversely, a ceramic membrane (MWCO 5 kDa) provided stable behaviour over several cycles of operation when cleaned with pure solvent at high cross velocity at 40 °C. This membrane showed high phospholipid retention (95±2 %), although some oil was also retained (16±3%). Cymene emerged as the most attractive of the three terpenes tested, with higher permeate flux and phospholipid rejection than limonene or pinene. Industrial Relevance: While hexane has been traditionally used for oilseed extraction, toxicity concerns are likely to restrict its industrial use in the future. This article provides information to engineers and food scientists on the use of terpenes as an alternative solvent. In particular, the potential for ultrafiltration to be used in degumming of canola oil/terpene mixture is assessed. Our research shows that polymeric membranes are unlikely to be useful at scale in this application, as they are not readily cleaned for reuse. Conversely, a ceramic membrane of 5 kDa pore size provides the necessary rejection of phospholipids. There is some oil retention, that might require a downstream recovery step. The best results were obtained with cymene, suggesting this is a good target for industrial use.

Time-lapse fluorescence microscopy is a valuable technology in cell biology, but it suffers from the inherent problem of intensity inhomogeneity due to uneven illumination or camera nonlinearity, known as shading artefacts. This will lead to inaccurate estimates of single-cell features such as average and total intensity. Numerous shading correction methods have been proposed to remove this effect. In order to compare the performance of different methods, many quantitative performance measures have been developed. However, there is little discussion about which performance measure should be generally applied for evaluation on real data, where the ground truth is absent. In this paper, the state-of-the-art shading correction methods and performance evaluation methods are reviewed. We implement 10 popular shading correction methods on two artificial datasets and four real ones. In order to make an objective comparison between those methods, we employ a number of quantitative performance measures. Extensive validation demonstrates that the coefficient of joint variation (CJV) is the most applicable measure in time-lapse fluorescence images. Based on this measure, we have proposed a novel shading correction method that performs better compared to well-established methods for a range of real data tested.