Investigation of FEM Simulation of Machining of Titanium Alloy Using Microgroove Cutting Insert

In this paper, FEM simulation of machining of titanium alloy using microgroove cutting insert has been carried out using DEFORM-3D software. The cutting insert with microgroove has been made with Solidworks software. The 3D machining simulations of all the different types of microgroove patterns in cutting inserts were done at constant cutting variable, i.e. cutting speed of 125.6 m/min, feed of 0.23 mm/rev and depth of cut of 2 mm respectively. The simulation results were partially validated with experiments. There was good agreement between experiment and simulation. The cutting temperature, effective stress, tool wear rate and temperature at the chip/tool interface has been determined. There was an improvement in the machinability criteria using cutting tool with microgroove pattern.     

Embedded metal nanoparticles as localized heat sources: An alternative processing approach for complex polymeric materials

Metal nanoparticles were utilized as heating elements within nanofibers to demonstrate an alternative approach to thermally process nanostructured polymeric materials. In the photothermal process, resonant light excites the surface plasmon of the nanoparticle and the absorbed energy is converted into heat due to electron-phonon collisions. This heating is efficient and strongly localized, generated from the nanometer-sized metal particles embedded within the polymer. Composite polyethylene oxide (PEO) nanofibers, containing differing concentrations and types of nanoparticles, were fabricated by electrospinning and irradiated by a low intensity laser tuned specifically to the metal nanoparticle surface plasmon absorbance; aggregation of fibers, loss of fibrous structure, and ultimately, complete melting were observed. The photothermal response to irradiation increased with nanoparticle concentration as long as particle aggregation was avoided. Pure PEO nanofibers, or those containing metal nanoparticles possessing a non-resonant surface plasmon, were also irradiated but no melting occurred, demonstrating the controllable specificity of this approach.     

Chiral macrocyclic salen Mn(III) complexes catalyzed enantioselective epoxidation of non-functionalized alkenes using NaOCl and urea H2O2 as oxidants

Two new chiral Mn(III) macrocyclic salen complexes 1a and 1b were prepared for the enantioselective epoxidation of non-functionalized alkenes. A 5 mol% loading of these catalysts in the presence of pyridine N-oxide as an axial base and sodium hypochlorite or urea hydrogen peroxide adduct as oxidant worked well to give respective epoxides in high yields and ee (up to >95% in selected cases). The catalyst 1b with urea hydrogen peroxide adduct as an oxidant was recovered by precipitation with hexane and was reused up to four times with retention of enantioselectivity.     

Symmetric electric double-layer capacitor containing imidazolium ionic liquid-based solid polymer electrolyte: Effect of TiO2 and ZnO nanoparticles on electrochemical behavior

Poly(vinylidene fluoride-co-hexafluoropropene) (PVDF–HFP)-based polymer electrolytes embedded with 1-ethyl-3-methylimidazolium tetrafluoroborate ioniliquid have been synthesized to improve the ionic conductivity. Electric double-layer capacitors (EDLC) have been prepared using the synthesized polymer electrolytes. Inorganic oxide fillers (5 wt %) such as titanium dioxide (TiO₂) and zinc oxide (ZnO) nanoparticles have been added to polymer electrolytes to compare the electrochemical behavior of the fabricated EDLC. The intrinsic dielectric constant of nanoparticles contributes in ionic dissociation which enhances ionic conductivity of electrolytes and also controls the specific capacitance of the EDLC fabricated with these electrolytes. Physicochemical properties of polymer nanocomposites have been investigated using X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared analysis, which confirms decrease of crystalline phase in host polymer PVDF–HFP. The maximum voltage stability is obtained for TiO₂-based polymer electrolyte. The high specific capacitance as well as high energy density is obtained for the EDLC cell with TiO₂-based polymer electrolyte compared to EDLC with ZnO nanoparticles-based electrolyte. EDLC cells show specific capacitance of 76.4 and 44.51% of initial specific capacitance value at 2000th cycle for ZnO and TiO₂-based polymer electrolytes, respectively. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48757.     

TiO2–ZrO2 mixed oxide as a support for hydrotreating catalyst

Pure TiO₂, ZrO₂ and TiO₂–ZrO₂ mixed oxides are prepared by urea hydrolysis. Hydrotreating catalysts containing 12 wt% molybdenum are prepared using these oxides and characterized by BET surface area, pore volume, XRD and oxygen chemisorption. It is observed that oxides produced by the method of urea hydrolysis have higher surface area as compared to those available commercially. With increasing zirconia content in the mixed oxide, the surface area increases and a maximum value is obtained for a mixed oxide having Ti and Zr molar ratio of 65/35. XRD results indicate that mixed oxides are poorly crystalline in nature. Thiophene hydrodesulfurization, cyclohexene hydrogenation and tetrahydrofuran hydrodeoxygenation are taken as model reactions for evaluating catalytic activities. It is found that both O₂ uptake and catalytic activities increase with increasing zirconia content in mixed oxide and reach maximum values for the 12 wt% Mo/TiO₂–ZrO₂ (65/35) catalyst. With further increases in zirconia content, O₂ uptake and catalytic activities decrease and the lowest values are observed for the pure ZrO₂ supported catalyst.     

Stearic acid as coupling agent in fly ash reinforced recycled polypropylene matrix composites: Structural,mechanical, and thermal characterizations

Two industrial wastes, fly ash (FA) and recycled polypropylene (RPP) were used to prepare a value‐added, sustainable, low cost composite material. Improving the interfacial interaction between the hydrophobic RPP matrix and the hydrophilic FA particles is important to get a good combination of properties. In order to tailor the interface, stearic acid was used as the coupling agent. The FA particles were coated with a saturated fatty acid, stearic acid (SA), in different weight % like 1, 2, 3, and 5. The SA coated fly ash particles were incorporated as filler in RPP matrix composites by melt mixing in 1 : 1 weight ratio. The composites were tested for their flexural properties, impact behavior, dynamic mechanical properties, fracture surface analysis, X‐ray diffraction (XRD) study, and differential scanning calorimetry (DSC). An increase in flexural modulus and impact strength was observed in the stearic acid coated FA/RPP composites. In 1 wt % SA treated FA/RPP (RFASA1) composites, a significant increase in glass transition temperature was observed along with an increase in crystallinity. A green, renewable, inexpensive chemical like stearic acid was thus found to be an effective coupling agent in fabrication of a composite with 50 wt % filler loading. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1996–2004, 2013     

Effect of blending technique on the properties of polyurethane and epichlorohydrin blends (sulfur cure)

Two elastomers having reactive functional groups may react with each other. Considering this, the blends of PU and EPH elastomers have been prepared where better performance properties can be tailored and optimized through the interchain crosslinking reaction. It is evident from the IR spectral analysis of the thin film of PU/EPH blend without curatives that an interchain crosslinking reaction occurs between the two elastomeric phases. Preheating of the preblends before addition of curatives enhances the properties of the blends. Thermal study revealed the delayed degradation with retardation in weight loss for the preheated, preblended samples. Preheating also restricted the extractability of the phases, by solvent, due to interchain crosslinking. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1367–1376, 2000     

Evaluation on Effectiveness of CVD and PVD Coated Tools during Dry Machining of Incoloy 825

With wide applications of nickel-based superalloys in strategic fields, it has become increasingly necessary to evaluate the performance of different advanced cutting tools for machining such alloys. With a view to recommend a suitable cutting tool, the present work investigated various machinability characteristics of Incoloy 825 using an uncoated tool, chemical vapor deposition (CVD) of a bilayer of TiCN/Al₂O₃, and physical vapor deposition (PVD) of alternate layers of TiAlN/TiN-coated tools under varying machining conditions. The influence of cutting speed (51, 84, and 124 m/min) as well as feed (0.08, 0.14, and 0.2 mm/rev) was comparatively evaluated on surface roughness, cutting temperature, cutting force, coefficient of friction, chip thickness, and tool wear using different cutting tools. Although the CVD-coated tool was not useful in decreasing surface roughness and temperature, a significant reduction in cutting force and tool wear could be achieved with the same coated tool under a high cutting speed of 124 m/min. On the other hand, the PVD-coated tool outperformed the other tools in terms of machinability characteristics. This might be attributed to the excellent antifriction and antisticking property of TiN and good toughness due to the multilayer configuration in combination with a thermally resistant TiAlN phase. Adhesion, abrasion, edge chipping, and nose wear were the prominent wear mechanisms of the uncoated tool, followed by the CVD-coated tool. However, remarkable resistance to such wear was evident with the PVD TiAlN/TiN multilayer-coated tool.