Increasing the aqueous solubility of acetaminophen in the presence of polyvinylpyrrolidone and investigation of the mechanisms involved

It was shown that the aqueous solubility of acetaminophen in the presence of polyvinylpyrrolidone (PVP) increased. The solubility at 25°C increased from 14.3 mg mL^-1 in the absence of PVP, to 19.7 mg mL^-1 in the presence of 4% w/v PVP, and to 26.7 mg mL^-1 in the presence of 8% w/v PVP. Dialysis studies indicated that there is a potential of binding between PVP and acetaminophen in their aqueous solutions. Dialysis studies also revealed that the nature of interaction between PVP and acetaminophen is physical and reversible, and there was no strong binding between PVP and acetaminophen in their solutions. Infrared spectroscopy of acetaminophen/PVP solid dispersion indicated that the mechanism of interaction between PVP and acetaminophen is via hydrogen bonding. Therefore, the increase in solubility of acetaminophen in the presence of PVP is probably attributed to its ability to form a water-soluble complex with PVP.     

A 0.2-W Heterostructure Barrier Varactor Frequency Tripler at 113 GHz

We present a high-power InAlAs/InGaAs/InP heterostructure barrier varactor (HBV) frequency tripler. The HBV device topology was designed for efficient thermal dissipation and high efficiency. To verify simulations, the device was flip-chip soldered onto embedding microstrip circuitry on an aluminum nitride substrate. This hybrid circuit was then mounted in a waveguide block without any movable tuners. From the resulting RF measurements, the maximum output power was 195 mW at 113 GHz, with a conversion efficiency of 15%. The measured 3-dB bandwidth was 1.5%     

Nanoelectromechanical Chip (NELMEC) Combination of Nanoelectronics and Microfluidics to Diagnose Epithelial and Mesenchymal Circulating Tumor Cells from Leukocytes

An integrated nano‐electromechanical chip (NELMEC) has been developed for the label‐free distinguishing of both epithelial and mesenchymal circulating tumor cells (ECTCs and MCTCs, respectively) from white blood cells (WBCs). This nanoelectronic microfluidic chip fabricated by silicon micromachining can trap large single cells (>12 µm) at the opening of the analysis microchannel arrays. The nature of the captured cells is detected using silicon nanograss (SiNG) electrodes patterned at the entrance of the channels. There is an observable difference between the membrane capacitance of the ECTCs and MCTCs and that of WBCs (measured using SiNG electrodes), which is the key indication for our diagnosis. The NELMEC chip not only solves the problem of the size overlap between CTCs and WBCs but also detects MCTCs without the need for any markers or tagging processes, which has been an important problem in previously reported CTC detection systems. The great conductivity of the gold‐coated SiNG nanocontacts as well as their safe penetration into the membrane of captured cells, facilitate a precise and direct signal extraction to distinguish the type of captured cell. The results achieved from epithelial (MCF‐7) and mesenchymal (MDA‐MB231) breast cancer cells circulated in unprocessed blood suggest the significant applications for these diagnostic abilities of NELMEC.     

Organometallic Bonding in an Ullmann‐Type On‐Surface Chemical Reaction Studied by High‐Resolution Atomic Force Microscopy

The on‐surface Ullmann‐type chemical reaction synthesizes polymers by linking carbons of adjacent molecules on solid surfaces. Although an organometallic compound is recently identified as the reaction intermediate, little is known about the detailed structure of the bonded organometallic species and its influence on the molecule and the reaction. Herein atomic force microscopy at low temperature is used to study the reaction with 3,9‐diiododinaphtho[2,3‐b:2′,3′‐d]thiophene (I‐DNT‐VW), which is polymerized on Ag(111) in vacuum. Thermally sublimated I‐DNT‐VW picks up a Ag surface atom, forming a C? Ag bond at one end after removing an iodine. The C? Ag bond is usually short‐lived, and a C? Ag? C organometallic bond immediately forms with an adjacent molecule. The existence of the bonded Ag atoms strongly affects the bending angle and adsorption height of the molecular unit. Density functional theory calculations reveal the bending mechanism, which reveals that charge from the terminus of the molecule is transferred via the Ag atom into the organometallic bond and strengths the local adsorption to the substrate. Such deformations vanish when the Ag atoms are removed by annealing and C? C bonds are established.     

Fault detection and diagnosis in synchronous motors using hidden Markov model-based semi-nonparametric approach

Early detection and diagnosis of faults in industrial machines would reduce the maintenance cost and also increase the overall equipment effectiveness by increasing the availability of the machinery systems. In this paper, a semi-nonparametric approach based on hidden Markov model is introduced for fault detection and diagnosis in synchronous motors. In this approach, after training the hidden Markov model classifiers (parametric stage), two matrices named probabilistic transition frequency profile and average probabilistic emission are computed based on the hidden Markov models for each signature (nonparametric stage) using probabilistic inference. These matrices are later used in forming a similarity scoring function, which is the basis of the classification in this approach. Moreover, a preprocessing method, named squeezing and stretching is proposed which rectifies the difficulty of dealing with various operating speeds in the classification process. Finally, the experimental results are provided and compared. Further investigations are carried out, providing sensitivity analysis on the length of signatures, the number of hidden state values, as well as statistical performance evaluation and comparison with conventional hidden Markov model-based fault diagnosis approach. Results indicate that implementation of the proposed preprocessing, which unifies the signatures from various operating speeds, increases the classification accuracy by nearly 21% and moreover utilization of the proposed semi-nonparametric approach improves the accuracy further by nearly 6%.     

Three-dimensional numerical investigation of film boiling by the lattice Boltzmann method

A three-dimensional lattice Boltzmann model is presented to simulate the film-boiling phenomenon. Single- and multimode film boilings are investigated. The flow and temperature fields around the vapor phase are obtained for various Jakob numbers. Furthermore, the effects of Jakob number on the Nusselt number and vapor tip velocity are investigated. The results show that on increasing the Jakob number, the bubble tip velocity increases while the Nusselt number decreases. Furthermore, it is found that in multimode film boiling, the peak and trough values of the local Nusselt number happen at the bubble position and the gap valleys between adjacent bubbles, respectively.     

Investigation on minimum quantity lubricant-MQL grinding of 100Cr6 hardened steel using different abrasive and coolant–lubricant types

Large quantities of coolant–lubricants are still widely used in the metal working industry, generating high consumption and discard costs and impacting the environment. Alternatives to current practices are getting more serious consideration in response to environmental and operational cost pressures. In the grinding process, promising alternatives to conventional dry and fluid coolant applications are minimum quantity lubrication (MQL) or near dry grinding process. Despite several researches, there have been a few investigations about the influence of different types of coolant–lubricants and grinding wheels on the process results. The current study aims to show the effects of the above parameters on grinding performance such as grinding forces and surface quality. The tests have been performed in presence of fluid, air jet and eleven types of coolant–lubricants, as well as, in dry condition. The grinding wheels employed in this study were vitrified bond corundum, resin bond corundum and vitrified bond SG wheels. The results indicate that SG wheels and MQL oils have potential for the development of the MQL process in comparison to vitrified and resin bond corundums and water miscible oils. Also, the lowest thermal damages, material side flow on the ground surface and wheel loading were generated by using the SG grinding wheel in MQL grinding process.     

Color image segmentation with genetic algorithm in a raisin sorting system based on machine vision in variable conditions

This study was undertaken to develop machine vision-based raisin detection technology for various lighting conditions. Supervised color image segmentation using a permutation-coded genetic algorithm (GA) identifying regions in hue–saturation–intensity (HSI) color space (GAHSI) for desired and undesired raisin detection in various conditions was successfully implemented. Images from two extreme intensity lighting and dense conditions: under weak lighting and high-density product and under suitable lighting and low-density product, were mosaicked to explore the possibility of using GAHSI to locate desired raisin and undesired raisin regions in color space when these two extremes were presented simultaneously. The GAHSI results provided evidence for the existence and separability of such regions. In the experiment, GAHSI performance was measured by comparing the GAHSI-segmented image with a corresponding hand-segmented reference image. When compared with cluster analysis-based segmentation results, the GAHSI method showed no significant difference.     

Nachgiebiger Elektrodenträger für Cochlea-Implantate mit fluidischer Aktuierung

The cochlear implant, consisting of a compliant electrode carrier (ET) and embedded electrodes with contact wires, is an auditory neuroprosthesis, which is surgically inserted into the inner ear (cochlea) in order to create an auditory impression in the hearing-impaired patients. For simplification of the insertion, a fluidically actuated electrode carrier with a changeable curvature is presented. The deformation of the ET is specifically manipulated by applying pressure to its interior and also by a non-stretchable thin fibre or stripe embedded in its wall. An analytical examination of scaling properties allows to use scaled structures for models and measurements. In order to determine the geometry of the ET, a model-based synthesis – FE method combined with analytical modelling – is carried out. The synthesis resulted in a conical shape of the ET with a cylindrical cavity closed at one end and a fiber running parallel to the cavity. Experimental studies on a measuring geometry show a maximum deviation of 0,6 bar at a maximum internal pressure of 6 bar. The investigations show that the proposed synthesis method is suitable for the development of surgical instruments with adjustable curvature.