Optimization of process parameters in micro milling of Ti4Al4Mo2Sn using nano Al2O3 additives based minimum quantity cooling lubrication

ABSTRACT. Aerospace and automotive industries employ Ti4Al4Mo2Sn material in many applications due to its properties of better strength to weight ratio and high corrosion resistance. Ti4Al4Mo2Sn finds itself difficult to cut materials due to its physical and chemical properties and is prone to more heat generation during machining. The more generation of heat affects the machined material surface quality and other related properties. In this investigation, the thermal conductivity and stability of Al2O3/Water based nanofluids are studied to select the best composition of nanofluid for transferring heat. The thermal conductivity and stability of the nanofluid for a duration of 30 days are computed by employing the KD2 thermal property meter and pH meter, respectively. Thermal conductivity and stability of the Water/4.5 vol.% Al2O3 nanofluid are found to be better than other combination of nanofluids. In the present study, optimizing the micro milling process parameters on Ti4Al4Mo2Sn material with Minimum quantity cooling lubrication (MQL) is focused. The input parameters selected for this micro milling process are spindle speed, feed rate, depth of cut and Water/4.5vol.% Al2O3 nanofluid and the output parameters selected are cutting forces in X(Fx) and Y(Fy) directions, tool wear rate (TWR) and surface roughness (SR). The optimization is done with the help of grey relational analysis (GRA) by using L9 Orthogonal Array (OA) Taguchi design. The obtained sequence of influencing parameters are feed rate per tooth, Al2O3nanofluid, spindle speed and depth of cut. The percentage of grey relational grade (GRG) for prediction and experimental is 0.721 and 0.957. The percentage of improvement of GRG is 12.46.   KEY WORDS: Ti4Al4Mo2Sn, Al2O3, Thermal conductivity, Grey relational analysis, Grey relational grade   Bull. Chem. Soc. Ethiop. 2022, 36(2), 339-351.                                                                DOI: https://dx.doi.org/10.4314/bcse.v36i2.

Synthesis, Characterization and Electrochemical Analysis of V-Shaped Disubstituted Thiourea-Chlorophyll Thin Film as Active Layer in Organic Solar Cells

Conjugated thiourea system has attracted considerable attention as potential molecular framework to construct molecular components for molecular electronics. To date, thiourea systems are surprisingly unexplored although the well-known rigid π-systems enhance the development of molecular wire architecture to be applied as potential organic solar cell (OSC). Regarding to this matter, a study on the performance of conjugated V-shaped disubstituted thiourea compound systems to act as potential active layer in OSC was carried out prior to form photovoltaic thin film. The compound namely N 1 ,N 3 -bis(4-(octyloxy)phenyl)-N-(benzene-1,3-dicarbonyl) thiourea was spectroscopically and analytical characterized via Fourier Transform Infrared (FT-IR), UV-Visible Analysis (UV-Vis), CHNS elemental analysis, 1H and 13C Nuclear Magnetic Resonance (NMR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) as well as Cyclic Voltammetry (CV) analysis. In turn, it was fabricated on Indium Tin Oxide (ITO) substrate before its conductivity behaviour, efficiency and OSC parameter were evaluated by Four Point Probe. From the electrical conductivity study, it revealed that the layer of ITO/V-shaped thiourea thin film exhibits higher conductivity, 0.1377Scm-1 with the presence of chlorophyll (CHLO) under maximum light intensity of 100 Wm-2 .Therefore, further evaluation of this type of molecular framework featuring thiourea moiety should be taken to enhance the development in the area of microelectronic devices

Electronic, reactivity and third order nonlinear optical properties of thermally-stable push-pull chalcones for optoelectronic interest: experimental and DFT assessments

The present work highlighted the integration of quantum chemical approach and experimental results in attempts to elucidate the structural-property characteristics and behaviour of the fused-aromatic chalcones on the impact of their nonlinear attribute at the molecular level. Two push-pull chalcones namely 1-(anthracen-9-yl)-3(9-ethyl-carbazol-3-yl)prop-2-en-1-one (1AECP) and 3(9-ethyl-carbazol-3-yl)-1(pyren-1-yl)prop-2-en-1-one (3ECPP) were successfully designed, synthesised and analysed through FT-IR, UV–Vis, 1D NMR, TGA, DSC and third-order optical nonlinearities were performed via Z-scan measurement. Concurrently, density functional theory (DFT) analysis with basis set of B3LYP/6-31G (d,p) was computed to optimize the most stable molecular geometry configuration, HOMO-LUMO energy gap, global chemical reactivity descriptors (GCRD), molecular electrostatic potentials (MEP), natural bond orbital (NBO) analysis and hyperpolarizability analyses. The experimental optical gap (Egopt) of both compounds has demonstrated good agreement with corresponding calculated result and fall in the range of organic semiconducting materials with low range of HOMO-LUMO energy gap values, 2.98 and 2.74 eV respectively. The DFT result revealed that fused-aromatic reinforce intramolecular charge transfer (ICT), electronic dipole moment and improve polarizabilities on NLO properties of the material. The thermal stability analysis pinpointed that both of these materials are able to withstand high temperature up to 300 °C which unintentionally unveil their encouraging performance potentially. Additionally, Z-scan analysis discovered that both of the targeted compounds are indeed nonlinear refraction (NLR) active, manifesting self-defocusing effect with n2 value of −1.75 x 10−9 esu (1AECP) and −1.75 x 10−8 esu (3ECPP). In short, the theoretical output complement the experimental results fundamentally in the evaluation and prediction of their electronic nature which hence proved their prospect essentially in the optoelectronic-manufacturing development