Fiber orientation is a key parameter affecting the geometrical, hydraulic and mechanical properties of nonwoven materials. The effect of fiber orientation on the pore size has been experimentally investigated based on air-laid, parallel-laid, and cross-laid structures following through-air bonding. It was evident that there is a discernible difference between the mean flow and maximum pore sizes of these nonwoven materials. The influence on pore size was further elucidated by evaluating experimental and theoretical models based on sieving-percolation pore network theory including a model that incorporates directional parameter to account for the effect of fiber orientation. It was established that good agreement with experimental data can be obtained using such a model.

The method for fast fabrication of superhydrophobic surfaces was proposed to resist the formation of biofilm of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) for orthopedic and dental implants. Laser beam machining with nanosecond pulsed laser (Nd:YAG) was used to fabricate pit structure on Grade-5 Ti–6Al–4V alloy followed by annealing (at 300 °C with different time scales) in order to reduce the transition time from hydrophilic to superhydrophobic surface generation. Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) techniques were used to characterize the textured samples. The surface wettability of plain and textured samples was measured by the sessile drop method using goniometer. The biofilm formation was qualitatively and quantitatively evaluated by FE-SEM and crystal violet binding assay, respectively. The biofilm formation was observed on plain (hydrophilic) surface for both the types of bacteria, whereas significantly less biofilm formation was observed on the laser textured (superhydrophobic) surfaces. The proposed method helps in reducing the risk of infection associated with implants without using cytotoxic bactericidal agents.

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The present work is an attempt to model the components of specific grinding energy in a pragmatic manner. This work explores the contribution of specific energy constituents such as shearing, primary rubbing, secondary rubbing, and ploughing energy while grinding Inconel 718 (IN-718) superalloy. Specific shearing energy has been calculated using the dynamic yield strength of IN-718 as obtained by adopting the Johnson–Cook material model. Specific rubbing energy has been estimated using real contact length measured experimentally. Rubbing grit density has been estimated by considering grinding infeed, grit size, wheel structure, and work material hardness unlike the previous models, where it was mostly taken as a constant value. Single grit grinding experiments have been performed with 36 and 20 mesh size single alumina grits to obtain the insight of ductile flow in IN-718 grinding. These experiments have been conducted at grinding speeds of 5, 10, and 15 m/s using vacuum brazed single alumina grit shank fitted into aluminium make dummy grinding wheel. Specific ploughing energy has been estimated after suitably apportioning the tangential forces as obtained from single grit grinding. Two-dimensional study of the scratch profiles has been performed using a compound microscope to investigate plausible ploughing mechanisms of IN-718. The present studies indicate that at lower infeeds, micro-fracturing of alumina grits is more recurrent, whereas wear flattening is more common at higher infeed. The higher pile-up ratio at lower infeed signifies more ploughing resulting into inefficient cutting causing more energy consumption. The micro-fracturing of single alumina grit while scratching has also been observed. The present model for specific grinding energy is an improved version of earlier energy models as it incorporates variables which are much closer to the actual grinding conditions.

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