Dual-mode colorimetric/fluorescent chemosensor for Cu2+/Zn2+ and fingerprint imaging based on rhodamine ethylenediamine bis(triazolyl silsesquioxane).

A novel dual functional and visual rhodamine ethylenediamine bis(triazolyl silsesquioxane) (RBS) chemosensor was successfully synthesized using "click" chemistry. The results have unambiguously demonstrated that RBS can act in fluorescent and colorimetric sensing of Cu2+ and Zn2+ by their respective coordination with triazole structures and, more importantly, it has also been found that triazole-amide of RBS could turn on chelation-enhanced fluorescence (CHEF) of Cu2+. Remarkably, the addition of Cu2+ triggered an enhanced fluorescent emission by 63.3-fold (ϕF = 0.41), while Zn2+ enhanced it 48.3-fold (ϕF = 0.29) relative to the original RBS (ϕF = 0.006) in acetonitrile (MeCN) solvent. The fluorescent limit of detection for Cu2+ and Zn2+ is similar and fall within 3.0 nM, while under colorimetric sensing the responses were 2.14 × 10-8 and 4.0 × 10-8 mol L-1, respectively. Moreover, the effective sensing profile of RBS and extended applications of RBS-Cu2+ and RBS-Zn2+ for fingerprinting detection and imaging were observed with adequate sensitivity, stability and legibility under the dual visual responses.

Data showing the effects of temperature and time variances on nano-additives treatment of mild steel during machining.

The effects of temperature and time variances on nano-additives treatment of mild steel during machining was presented in this study. Mild steel of 150 kg mass containing 0.56% carbon was charged into the furnace at melting and pouring temperature of 1539 and 1545 °C respectively. Also charged into the furnace with the mild steel were 0.05% max phosphorous and a bit of sulphur. Thereafter, the sample was cooled and annealed at a temperature of 900 °C for 9 h and then cooled to 300 °C of hardening, normalizing and tempering respectively. The treated samples were then soaked with pulverized in palm kernel shell and barium carbonate (20%) energizer at respective temperatures (800, 850, 900 and 950 °C) and time variances (60, 90 and 120 min) in a muffle furnace. The developed tool was tested on a lathe machine to evaluate its performance. The surface and core hardness, wear resistance and toughness were carried out using the hardness tester, Rotopol-V and impact tester respectively. This is essential for predicting the useful life of the tool in service.