Wear characteristics of ultra-hard cutting tools when machining austempered ductile iron

Nodularised Ductile Cast Iron, when subjected to heat treatment processes - austenitising and austempering produces Austempered Ductile Iron (ADI). The microstructure of ADI also known as "ausferrite" consists of ferrite, austenite and graphite nodules. Machining ADI using conventional techniques is often a problematic issue due to the microstructural phase transformation from austenite to martensite during machining. This paper evaluates the wear characteristics of ultra hard cutting tools when machining ADI and its effect on machinability. Machining trials consist of turning ADI (ASTMGrade3) using two sets of PCBN tools with 90% and 50% CBN content and two sets of ceramics tools; Aluminium Oxide Titanium Carbide and Silicon Carbide - whisker reinforced Ceramic. The cutting parameters chosen are categorized as roughing and finishing conditions; the roughing condition comprises of constant cutting speed (425 m/min) and depth of cut (2mm) combined with variable feed rates of 0.1, 0.2, 0.3 and 0.4mm/rev. The finishing condition comprises of constant cutting speed (700 m/min) and depth of cut (0.5mm) combined with variable feed rates of 0.1, 0.2, 0.3 and 0.4mm/rev. The benchmark condition to evaluate the performance of the cutting tools was tool wear evaluation, surface texture analysis and cutting force analysis. The paper analyses thermal softening of the workpiece by the tool and its effect on the shearing mechanism under rough and finish machining conditions in term of lower cutting forces and enhanced surface texture of the machined part.

Novel alginate-enclosed chitosan–calcium phosphate-loaded iron-saturated bovine lactoferrin nanocarriers for oral delivery in colon cancer therapy

Aim: To develop polymeric-ceramic nanocarriers (NCs) in order to achieve oral delivery of the anticancer neutraceutical iron-saturated bovine lactoferrin (Fe-bLf) protein.

Materials & methods: Fe-bLf or paclitaxel (Taxol®) were adsorbed onto calcium phosphate nanocores, enclosed in biodegradable polymers chitosan and alginate. The Fe-bLf or Taxol-loaded NCs indicated as AEC–CP–Fe-bLf or AEC–CP–Taxol NCs, respectively, were made by combination of ionic gelation and nanoprecipitation. Size distribution, morphology, internalization and release profiles of the NCs were studied along with evaluation of in vitro and in vivo anticancer activities and compared with paclitaxel.

Results: AEC–CP–Fe-bLf NCs obtained spherical morphology and showed enhanced endocytosis, transcytosis and anticancer activity in Caco-2 cells in vitro. AEC–CP–Fe-bLf NCs were supplemented in an AIN 93G diet and fed to mice in both prevention and treatment human xenograft colon cancer models. AEC–CP–Fe-bLf NCs were found to be highly significantly effective when given orally, as a pretreatment, 1 week before Caco-2 cell injections. None of the mice from the AEC–CP–Fe-bLf NC-fed group developed tumors or showed any signs of toxicity, while the mice fed the control AIN 93G diet showed normal tumor growth. Fe-bLf or Taxol, when given orally in a diet as nanoformulations post-tumor development, showed a significant regression in the tumor size with complete inhibition of tumor growth later, while intratumoral injection of Taxol just delayed the growth of tumors. The pharmacokinetic and bioavailability studies indicated that nanoformulated Fe-bLf was predominantly present on tumor cells compared to non-nanoformulated Fe-bLf. Fe-bLf-loaded NCs were found to help in absorption of iron and thus may have utility in enhancing the iron uptake during iron deficiency without interfering with the absorption of calcium.

Conclusion: With the promising results of our study, the future potential of NC-loaded Fe-bLf in chemoprevention and in the treatment of human colon cancer, deserves further investigation for translational research and preclinical studies of other malignancies.

Mild and cost-effective synthesis of iron fluoride-graphene nanocomposites for high-rate Li-ion battery cathodes

Exploring high performance cathode materials is essential to realize the adoption of Li-ion batteries for application in electric vehicles and hybrid electric vehicles. FeF3, as a typical iron-based fluoride, has been attracting considerable interest due to both the high electromotive force value of 2.7 V and the high theoretical capacity of 237 mA h g_1 (1e_ transfer). In this study, we report a facile lowtemperature solution phase approach for synthesis of uniform iron fluoride nanocrystals on reduced graphene sheets stably suspended in ethanol solution. The resulting hybrid of iron fluoride nanocrystals and graphene sheets showed high specific capacity and high rate performance for iron fluoride type cathode materials. High stable specific capacity of about 210 mA h g_1 at a current density of 0.2 C was achieved, which is much higher than that of LiFePO4 cathode material. Notably, these iron fluoride/ nanocomposite cathode materials demonstrated superior rate capability, with discharge capacities of 176, 145 and 113 mA h g_1 at 1, 2 and 5 C, respectively.