Boric Ester-Type Molten Salt via Dehydrocoupling Reaction

Novel boric ester-type molten salt was prepared using 1-(2-hydroxyethyl)-3-methylimidazolium chloride as a key starting material. After an ion exchange reaction of 1-(2-hydroxyethyl)-3-methylimidazolium chloride with lithium (bis-(trifluoromethanesulfonyl) imide) (LiNTf₂), the resulting 1-(2-hydroxyethyl)-3-methylimidazolium NTf₂ was reacted with 9-borabicyclo[3.3.1]nonane (9-BBN) to give the desired boric ester-type molten salt in a moderate yield. The structure of the boric ester-type molten salt was supported by ¹H-, ¹³C-, ¹¹B- and ¹⁹F-NMR spectra. In the presence of two different kinds of lithium salts, the matrices showed an ionic conductivity in the range of 1.1 × 10⁻⁴–1.6 × 10⁻⁵ S cm⁻¹ at 51 °C. This was higher than other organoboron molten salts ever reported.     

Nanocrystalline diamond microspikes increase the efficiency of ultrasonic cell lysis in a microfluidic lab-on-a-chip

This research demonstrates that use of Nanocrystalline Diamond (NCD) microspikes in a microfluidic chamber increases the efficiency of mechanical cell lysis, as compared to a standard microfluidic surface such as glass. Microspikes made of nanocrystalline diamond were fabricated using standard MEMS techniques, and were incorporated in microfluidic chamber developed as part of a lab on a chip system. Mechanical cell lysis was performed on B16-F10 (ATCC CRL-6475) murine melanoma cells using ultrasonic vibration and the efficiency of cell lysis was determined. The microspikes puncture the cell membranes on collision greatly increasing the efficiency of cell lysis (about 400% as per fluorescence measurements) as compared to a non-textured glass surface. The effect of using cell disruption glass beads during ultrasonic lyses was also explored. This methodology of cell disruption could potentially make mechanical cell lysis a viable and preferred lysis option for lab-on-a-chip applications.     

Hydrodynamics of churn turbulent bubble columns: gas–liquid recirculation and mechanistic modeling

A phenomenological (mechanistic) model has been developed for describing the gas and liquid/slurry phase mixing in churn turbulent bubble columns. The gas and liquid phase recirculation rates in the reactor, which are needed as inputs to the mechanistic reactor model are estimated via a sub-model which uses the two-fluid approach in solving the Navier–Stokes equations. This sub-model estimates the effective bubble diameter in the reactor cross-section and provides a consistent basis for the estimation of the volumetric mass transfer coefficients. The strategy for the numerical solution of the sub-model equations is presented along with the simulation results for a few cases. The overall reactor model has been tested against experimental data from radioactive gas tracer experiments conducted at the Alternate Fuels Development Unit (AFDU), La Porte, TX under conditions of methanol synthesis.     

Mathematical modeling for the design of a generic custom-engineered form mill

This paper presents a mathematical model for the geometric design of a custom-engineered form milling (CEFM) cutter and develops an accurate 3D surface-based generic definition of the form mill. The proposed geometric definition of the CEFM cutter is developed in terms of biparametric surface patches using newly defined 3D rotational angles rather than the conventional 2D angles. The non-uniform rational B-spline curve fairing and sweep surface approaches are used to design the cutting edge and flank surface, respectively, of the cutter. To validate the methodology, an interface is developed that converts the proposed 3D parametric definition of the cutter into an intermediate neutral CAD format and then renders the cutter model in any CAD modeling environment. The accuracy of the mathematical model is verified by evaluating the deviation plot between the surfaces of the proposed cutter model and the surfaces developed using digitized data of an existing actual CEFM cutter. The satisfactory comparison verifies the shape design methodology for custom cutters presented in this paper. The method described here offers a simple and intuitive way of generating shape design of custom cutters for possible use in machining process simulations, finite element analysis, and other applications.     

Study of Carbon Nanotubes in Cu-Cr Metal Matrix Composites

A novel metal matrix composite (MMC), Cu-Cr-MWCNT (copper-chromium-multiwalled carbon nanotube), was manufactured using a powder metallurgy technique. Cu-Cr alloy is widely adopted for contacts in vacuum circuit breakers. MWCNT was incorporated in an effort to enhance electrical conductivity and decrease the usage of Cr as strategic metal. Optimized milling conditions and sintering profiles were utilized to minimize any significant damage to the MWCNTs but yet provide homogeneous distribution of all constituents. Raman spectroscopy, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were used to determine the crystal structure orientation, microstructure, and morphology, respectively, of the composite. Raman peak shift and intensity ratios assessed the stresses induced and the degree of disorder of MWCNTs in the composite. TEM indicated carbide and oxide formations in the composite. SEM images revealed the presence of MWCNTs within the metal matrix. The corrosion resistances of the composite with and without MWCNTs was determined by cyclic potentiodynamic polarization (ASTM F 2129-08) in phosphate buffer saline solution at 37 °C.     

Influence of sunflower oil based nanoemulsion (AUSN-4) on the shelf life and quality of Indo-Pacific king mackerel (Scomberomorus guttatus) steaks stored at 20 °C

The influence of nanoemulsion (AUSN-4) on the microbiological, proximal, chemical, and sensory qualities of Indo-Pacific king mackerel (Scomberomorus guttatus) steaks stored at 20 °C was studied for a time period of 72 h. AUSN-4 treatment showed initial reduction (P > 0.05) in the heterotrophic, H₂S and lactic acid bacterial populations in 12 h, followed by a gradual increase in their respective populations. Irrespective of treatments, reduction in total carbohydrate, protein, and fat contents were observed in all samples with an increase in storage time (h), with AUSN-4 treated steaks having the lowest reduction. AUSN-4 treatment significantly (P < 0.05) decreased the values of chemical indicators of spoilage throughout the storage period. Organoleptic evaluation revealed that AUSN-4 treated steaks showed an extension of shelf life of 48 h, when compared with control and antibiotic treated samples, respectively. Based on the results obtained in our present study we conclude that sunflower oil based nanoemulsion preservative technique is able to extend the shelf life and maintain the quality of S. guttatus steaks during storage.     

Hyperparameter search based convolution neural network with Bi-LSTM model for intrusion detection system in multimedia big data environment

Multimedia Tools and Applications - In recent years, there is an exponential increase in the growth of the multimedia data, which is being generated from zettabyte to petabyte scale. At the same...     

A method for monitoring head media spacing change in a hard disk drive using an embedded contact sensor

Growth in the demand for higher capacity hard disk drives has pushed the requirement for head-media spacing to sub-nanometer levels. The drop in operational clearance makes a head-disk interface more susceptible to potential head-wear and contamination related issues. Such degradation processes are often accompanied by a noticeable shift in the head-disk clearance. Hence monitoring an interface for a spacing change can be helpful in early detection of its imminent failure. In this paper, we present a method to detect the change in head-disk spacing using an embedded contact sensor (ECS). This technique involves the analysis of ECS dynamic response for an interface that is subjected to heater induced spacing modulations. As the head moves closer to the disk surface, the magnitude of the ECS frequency components can be used to determine the ‘characteristic spacing’ which can be used as a metric to detect any physical change for a given interface.

     

Enhancement of Process Capabilities and Numerical Prediction of Geometric Profiles and Global Springback in Incrementally Formed AA 1050 Sheets

In single point incremental forming (SPIF) process, parts suffer from dimensional inaccuracy and limited formability, mainly, due to occurrence of springback and abrupt fracture, respectively. Orientation imaging microscopy of the original AA1050 sheet revealed dislocated and distorted microstructure and texture in comparison to the same sheet preheated at different temperatures. The objective of this work is to investigate formability and geometrical accuracy due to variations in microstructure and texture of the sheet and to propose a methodology, which can predict the geometric profiles and springback effect at different preheating temperatures. The work reports enhanced formability and geometrical accuracy of parts formed by SPIF, owing to the reformation of grain structure due to preheating. However, preheating at higher temperatures, i.e., 330 and 500 °C deteriorated the surface quality, as homogenization of grain orientation led to orange peel effect. The proposed methodology, based on reverse engineering and numerical formulation, is capable of predicting two-dimensional cone and pyramid profiles as well as global spring back values associated with different preheating temperatures. The results predicted by proposed method were validated by experiments and could be implemented to enhance the accuracy of SPIF process.     

Transient Dynamic Response of Clamped-Free Hybrid Composite Circular Cylindrical Shells

Dynamic response of multilayer circular cylindrical shells composed of hybrid composite materials subjected to lateral impulse load is studied in this paper. The boundary conditions (B.C.s) are considered to be clamped-free. Both isotropic (metal) and orthotropic (composite) layers are used simultaneously in the hybrid lamination. There is no limitation for fibre orientation. First order shear deformation theory (FSDT) and Love’s first approximation theory are utilized in the shell’s equilibrium equations. Equilibrium equations for free and forced vibration problems of the shell are solved using Galerkin method. Finally, time response of displacement components of Fibre-Metal Laminate (FML) cylindrical shells is derived using mode superposition method. The effect of lay up, material properties, fibre orientation and volume fraction of metal layers on the dynamic response of the shell are investigated. New interesting results are obtained and discussed providing a helpful insight for aircraft structure’s designers.