Design and manufacturing of femoral stems for the Indian population

Several researchers have stressed the need for a proper implant-patient match in hip joint replacements, in particular, for cementless femoral stems. Some of the complications of mismatch are aseptic loosening, improper load distribution, and discomfort. In this study, the differences in dimensions between femurs of elderly Indians and those of populations from other regions are compared in order to solve the problem of a possible geometric mismatch between a selected implant and the femurs of an Indian patients are concerned. This paper also describes a methodology for implant designing from measured anthropometric data, fit evaluation, finite element (FE) stress analysis and subsequently implant manufacturing using the CAM (Computer Aided Manufacturing) technique. The machining of the Titanium alloy femoral stem is usually performed on a 5 Axis CNC (Computer Numerical Control) machining center. However, in this study the machining of the femoral stem was effectively performed on a 3 Axis CNC machining center to emphasize on economical benefits for low cost manufacturing strategy.     

Enhancing viability of biofuel-based decentralized power projects for rural electrification in India

Decentralized power generation, using locally available biofuels from non-edible oilseeds, is an option for rural electrification in many developing countries. However, due to prevailing high price of non-edible oilseeds, such as Jatropha curcas, the cost of electricity generation is very high. This paper provides detailed financial analysis of straight vegetable oil (SVO)-based decentralized power project and proposes an innovative model for enhancing their financial viability. While for implementing agency operational cost recovery is the key for viability, affordable tariff is crucial for end-users. The paper attempts to estimate minimum desired price of electricity from the stakeholders' (producer and users) perspective using data gathered from selected operational SVO-based power generation projects in India. Analysis carried out in this paper indicates that operating the decentralized power plant at higher capacity utilization factor, by introduction of productive load, and differentiated tariffs for commercial and domestic consumers may not alone be sufficient to achieve the financial viability. The paper proposes an innovative integrated model of using biogas, obtained from the by-product de-oiled cake of non-edible oilseeds, as a feedstock for power generation, instead of using the SVO in engines. This reduces the fuel cost of power generation, thereby helping to bring down the tariff within the paying capacity of rural consumers. The main produce, viz. extracted non-edible oil, which was otherwise used as fuel for generating power, can be sold in local market for earning revenue, thereby enhancing the project’s economic viability. This paper sets forth the proposed integrated model as a viable biofuel-based decentralized power project for sustainable rural development in areas with adequate availability of oilseeds.     

Analytical prediction of stepped feature generation in multi-pass single point incremental forming

Single point incremental forming (SPIF) is a new sheet metal forming process characterized by higher formability, product independent tooling and greater process flexibility. The inability of conventional single pass SPIF to form vertical walls without failure is overcome by forming multiple intermediate shapes before forming the final component, i.e., multi-pass single point incremental forming (MSPIF). A major issue with MSPIF is significant geometric inaccuracy of the formed component, due to the generation of stepped features on the base. This work proposes analytical formulations that are shown to accurately and quantitatively predict the stepped feature formation in MSPIF. Additionally, a relationship is derived among the material constants used in these analytical equations, the yield stress and thickness of the blank material, such that the computational effort required for the calibration of these constants can be minimized. Finally, the physical effects of yield stress and sheet thickness on the rigid body translation are further discussed.     

Toxicity of various anions associated with methoxyethyl methyl imidazolium-based ionic liquids on Clostridium sp

We investigated the effects on the growth of the anaerobic bacterium, Clostridium sp., of the ionic liquid, 1-methoxyethyl-3-methyl imidazolium [MOEMIM]⁺, derived from imidazolium cation and paired with one of a variety of counter-ions, viz., tetrafluoroborate [BF₄]^-, hexafluorophosphate [PF₆]^-_, trifluoroacetate [CF₃COO]^-, bis(trifluoromethane)sulfonamide [Tf₂N]^-, methane sulfonate [OMS], and 1-butyl-3-methyl imidazolium tetrafluoroborate [BMIM][BF₄]. These anions, in association with [MOEMIM]⁺ lowered the growth rate of the bacterium, showing the following trend: [Tf₂N]^- ≧ [PF₆]^- > [BF₄]^- > [CF₃COO]^- > [OMS]⁻. Anions incorporating fluorine were more toxic than those without it, and their toxicity rose with an increase in the number of fluorine atoms. Also, [MOEMIM]⁺[BF₄]^- was less toxic than [BMIM]⁺[BF₄]^-, probably due to the presence of a methoxyethyl functional group integrated in the cation side chain.     

Coping with the ‘Indian summer’: unique nesting cycle and nest architecture of the paper wasp,Polistes wattii

The Science of Nature - Leaf-cutting ants are highly successful herbivores in the Neotropics. They forage large amounts of fresh plant material to nourish a symbiotic fungus that sustains the...     

Toxicity of imidazolium- and pyridinium-based ionic liquids and the co-metabolic degradation of N-ethylpyridinium tetrafluoroborate

We examined the effects of the ionic liquids (ILs), 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF₆], N-ethylpyridinium tetrafluoroborate [EtPy][BF₄], and N-ethylpyridinium trifluoroacetate [EtPy][CF₃COO] on Pseudomonas fluorescens, a ubiquitous soil bacterium. In the presence of 0.5- and 1% of [BMIM][PF₆] or [EtPy][CF₃COO] the growth of bacteria was inhibited, whereas exposing them to 1% [EtPy][BF₄] increased the lag period wherein bacteria adapt to growth conditions before continuing to grow. However, at higher concentrations (5% and 10%), no growth was observed. The inhibitory effects were evident by a decrease in the optical density of the culture, a decline in the consumption of the carbon source, citric acid, and a change in the size of the bacterium. At concentrations below 1%, [EtPy][BF₄] was metabolized by P. fluorescens in the presence of citric acid. Oxidation of the side alkyl-chain of [EtPy][BF₄] caused the accumulation of N-hydroxylethylpyridinium and pyridinium as major degradation products.     

Laccase-mediated delignification and detoxification of lignocellulosic biomass: removing obstacles in energy generation

Environmental Science and Pollution Research - The rising global population and worldwide industrialization have led to unprecedented energy demand that is causing fast depletion of fossil...     

Characterization of value-added chemicals derived from the thermal hydrolysis and wet oxidation of sewage sludge

• Hydrothermal treatment can greatly improve resource recovery from sewage sludge. • tCOD removal during WO was ~55% compared with ~23% after TH. • TOC solubilization during hydrothermal treatment followed first-order kinetics. • Solids and carbon balance confirmed loss of organics during thermal hydrolysis. • Reaction pathways for thermal hydrolysis and wet oxidation are proposed. We evaluated the effect of hydrothermal pretreatments, i.e., thermal hydrolysis (TH) and wet oxidation (WO) on sewage sludge to promote resource recovery. The hydrothermal processes were performed under mild temperature conditions (140°C–180°C) in a high pressure reactor. The reaction in acidic environment (pH= 3.3) suppressed the formation of the color imparting undesirable Maillard’s compounds. The oxidative conditions resulted in higher volatile suspended solids (VSS) reduction (~90%) and chemical oxygen demand (COD) removal (~55%) whereas TH caused VSS and COD removals of ~65% and ~27%, respectively at a temperature of 180°C. During TH, the concentrations of carbohydrates and proteins in treated sludge were 400–1000 mg/L and 1500–2500 mg/L, respectively. Whereas, WO resulted in solids solubilization followed by oxidative degradation of organics into smaller molecular weight carboxylic acids such as acetic acid (~400–500 mg/L). Based on sludge transformation products generated during the hydrothermal pretreatments, simplified reaction pathways are predicted. Finally, the application of macromolecules (such as proteins), VFAs and nutrients present in the treated sludge are also discussed. The future study should focus on the development of economic recovery methods for various value-added compounds.     

Borderline microscopic organism and lockdown impacted across the borders—global shakers

Environmental Science and Pollution Research - Viruses are the potential cause of several diseases including novel corona virus-19, flu, small pox, chicken pox, acquired immunodeficiency syndrome,...