Analytical and chemometric applications in the study of automotive and related lubricant degradation

Chemometric techniques have been utilised for the study of automotive lubricant oil degradation. The initial investigations were performed by analysis of data from top ring zone engine test datasets. Principal component analysis (peA) was used to explore the ring zone data. The difference in the performance of various lubricant formulations sampled from the ring zone region of operating Petter AA-I diesel and Petter W-1 petrol engines was established by the partial least squares discriminant model (PLS-DA). The results from the study of the test engine data provided optimised insight into the break down of the chemical/physical parameters of the lubricants during operative conditions. This work proceeded onto condition monitoring techniques. Over a hundred used oil samples were obtained from the sump of various petrol and diesel engine vehicles, in addition fresh oil samples were also collected. Series sets of used oil samples were acquired by periodic sampling from a Honda 1.8 L petrol engine, a Peugeot 1.9 L diesel engine and a diesel engine sump test. Following sample acquisition, each oil sample was analysed using FTIRIATR and conductimetric titrations were performed. These analytical equipments are used to monitor and assess the extent of degradation. A novel model was developed to enhance the IP 400 conductimetric titration method of measuring base number of new and used lubricants. This nonlinear least-squares model was integrated into the titration programme along with two linear least-squares curve fitting methods. The models were effectively used to estimate the titration endpoint which was subsequently used in base number calculation. The results demonstrated the robustness of the three endpoint estimation methods and indicate reliability of the titration equipment and programme. peA was used to analyse the FTIR spectra data of the oil samples. peA performed on different sets of pre-processed data uncovered objective information on the condition of the lubricants. peA models of the series set oil samples highlighted difference between samples as a result of progressive degradation. The effect of adding fresh oil (top-up) to the engine was apparent. This work has demonstrated the importance and efficiency of mathematical/statistical models in lubricant oil engine testing and condition monitoring

Occlusion of polymeric capsules in calcite single crystals for storage of active pharmaceutical ingredients

Developing a new drug storage system is imperative, especially for macromolecules with limited shelf-lives, pharmaceutical cures for unforeseeable epidemics, and drugs with short-lived therapeutic windows. In this work, calcite is proposed as a new system for drug storage. Since it is a single crystal, it is impenetrable by the primary agents of decay (oxygen, humidity and UV radiation). The system explored in this work achieved 20% occlusion in mass, which is 5% higher than the most excellent occlusion reported in the literature. This is the first evidence of a neutral capsule occluded inside of calcite, which breaks with the assumption that charge is a requisite for crystal-additive interactions. Using CLSM and FIB-SEM tomography, three-dimensional models are built of the occluded capsules in crystals. The occlusion patterns observed revolve around the third-order axis of symmetry. Size selectivity of around 1 µm has been calculated, although most of the occluded capsules observed are in the 100-300 nm range. We propose that this system be applied at the manufacturer scale and that the drugs stored in the crystals can later be processed into consumer-ready pharmaceuticals when needed. The pharmaceutical industry can apply this technology to control the spread of infectious diseases or simply profit from price fluctuations on synthetic precursors