Alkaline treatment effect on the properties of in‐situ synthesised ZnO nanoparticles on cotton fabric

In this study, an in‐situ approach was used to synthesise zinc oxide nanoparticles on the surface of cotton fabric. The effect of alkaline pre‐ and after‐treatment and Zn²⁺ concentration was studied on the morphological, structural, thermal, photocatalytic, and antibacterial properties of loaded cotton fabrics. Scanning electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray diffractometer, thermogravimetric analysis, and attenuated total reflection Fourier transform infrared spectrometer were used to characterise the properties of loaded cotton fabrics. Alkaline after‐treatment of cotton fabric presented more dispersed zinc oxide nanoparticles, and an increase in Zn²⁺ concentration led to form agglomerated nanoparticles on the surface of cotton fibres. The loaded cotton fabrics with zinc oxide nanoparticles presented an inhibition zone against Staphylococcus aureus and Escherichia coli. In addition, the stain of methylene blue on the surface of loaded samples was degraded after irradiated under visible light.Inspec keywords: nanofabrication, zinc compounds, II‐VI semiconductors, nanoparticles, nanomedicine, antibacterial activity, catalysis, photochemistry, cotton fabrics, scanning electron microscopy, X‐ray chemical analysis, X‐ray diffraction, thermal analysis, attenuated total reflection, Fourier transform infrared spectroscopy, microorganisms, materials preparationOther keywords: alkaline treatment effect, in‐situ synthesised ZnO nanoparticles, alkaline pretreatment, alkaline after‐treatment, Zn²⁺ concentration, morphological property, structural property, thermal property, photocatalytic property, antibacterial property, loaded cotton fabrics, scanning electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray diffractometer, thermogravimetric analysis, attenuated total reflection Fourier transform infrared spectrometer, agglomerated nanoparticles, zinc oxide nanoparticles, inhibition zone, Staphylococcus aureus, Escherichia coli, methylene blue, visible light, ZnO     

Dual Growth Factor Delivery Using Biocompatible Core–Shell Microcapsules for Angiogenesis

An optimized electrodropping system produces homogeneous core–shell microcapsules (C‐S MCs) by using poly(L ‐lactic‐co‐glycolic acid) (PLGA) and alginate. Fluorescence imaging clearly shows the C‐S domain in the MC. For release control, the use of high‐molecular‐weight PLGA (HMW 270 000) restrains the initial burst release of protein compared to that of low‐MW PLGA (LMW 40 000). Layer‐by‐layer (LBL) assembly of chitosan and alginate on MCs is also useful in controlling the release profile of biomolecules. LBL (7‐layer) treatment is effective in suppressing the initial burst release of protein compared to no LBL (0‐layer). The difference of cumulative albumin release between HMW (7‐layer LBL) and LMW (0‐layer LBL) PLGA is determined to be more than 40% on day 5. When dual angiogenic growth factors (GFs), such as platelet‐derived GF (PDGF) and vascular endothelial GF (VEGF), are encapsulated separately in the core and shell domains, respectively, the VEGF release rate is much greater than that of PDGF, and the difference of the cumulative release percentage between the two GFs is about 30% on day 7 with LMW core PLGA and more than 45% with HMW core PLGA. As for the angiogenic potential of MC GFs with human umbilical vein endothelial cells (HUVECs), the fluorescence signal of CD31+ suggests that the angiogenic sprout of ECs is more active in MC‐mediated GF delivery than conventional GF delivery, and this difference is significant, based on the number of capillary branches in the unit area. This study demonstrates that the fabrication of biocompatible C‐S MCs is possible, and that the release control of biomolecules is adjustable. Furthermore, MC‐mediated GFs remain in an active form and can upregulate the angiogenic activity of ECs.     

Improvement of Near-Dry Machining and Its Effect on Tool Wear in Turning of AISI 4142

In this study, improvement of near-dry machining (NDM) and its effect on tool wear in turning of AISI 4142 by carbide tool (DNMG 150608-PM) is investigated. First, the preparation of experimental setup was carried out, and then, some experiments to study the process were performed. Surface roughness was used as the criterion of finding the optimal conditions of fluid flow rate and frequency, and position and angle of nozzle. After optimization of the process, some experiments were performed to study tool life. Machining force, roughness, and tool wear were chosen as the criteria to determine the tool life. Obtained results show that the tool life in NDM is longer than that in dry machining.     

Inactivation of Escherichia coli K-12 in Apple Juice Using Combination of High-Pressure Homogenization and Chitosan

ABSTRACT:  Apple juice and apple cider were inoculated with Escherichia coli K-12 and processed using a high-pressure homogenizer to study bacterial inactivation. Seven levels of pressure ranging from 50 to 350 MPa were used in the high-pressure homogenizer. Two types of chitosan (regular and water soluble) with 2 levels of concentration 0.01% and 0.1% were investigated for synergistic effect with high-pressure homogenization for the bacterial inactivation. E. coli K-12 inactivation was evaluated as a function of homogenizing pressure at different concentration of 2 types of chitosan in apple juice and cider. High-pressure homogenization (HPH) induced significant inactivation in the range of 100 to 200 MPa, while thermal inactivation was the primary factor for the bacterial inactivation above 250 MPa. Significant ( P < 0.05) 2-way interactions involving pressure and type of substrate or pressure and chitosan concentration were observed during the study. The homogenization pressure and the incremental quantity of chitosan (both types) acted synergistically with the pressure to give higher inactivation. Significantly ( P < 0.05) higher inactivation was observed in apple juice than apple cider at same homogenizing pressure. No effect of type of chitosan was observed on the bacterial inactivation.     

Rotational Stiffness and Damping Coefficients of Fluid Film in a Finite Cylindrical Bearing

The dynamic behavior of flexible rotors supported on fluid-film bearings are studied including the rotational stiffness and damping coefficients of the oil film. The rotational stiffness and damping coefficients have been evaluated for a finite cylindrical fluid-film bearing by solving the appropriate Reynolds equation for the oil film, using finite difference method. The resulting critical speeds and the unbalance response for a single-disk flexible-rotor system modelled by finite element method are compared with those which were obtained using a short bearing approximation.     

A morphological study on direct polymer cast micro-textured hydrophobic surfaces

The surface microstructures that contribute to the lotus leaf's superhydrophobicity are replicated onto a polymer surface using a two-stage (negative-positive) direct casting method and the replicates' surface morphology is investigated in this study. Vinyl polysiloxane (VPS), polydimethylsiloxane (PDMS) and polymethylmethacrylate (PMMA) are used for the replication and the replicates obtained are investigated using confocal microscopy, scanning electron microscopy (SEM), and contact angle measurements. Geometric texture parameters such as peak height, peak/valley base width and inter-spacing between adjacent peak/valleys are measured for the lotus leaf and its replicates. Of the six combinations of positive and negative replicates attempted, VPS-PMMA and PDMS-PMMA replicates display shorter peak heights and larger base widths. These replicates have contact angles of 132.1° and 129.2° respectively, which are closest to the contact angle of the lotus leaf, 152.9°. Statistical two sample t-test revealed that VPS-PMMA's surface morphological parameters are closest to that of the lotus leaf. Also, theoretical calculations, based on two different methods from literature, using the measured geometric texture parameters show that polymer replicates satisfy criteria for a stable Cassie-Baxter wetting regime.     

A Novel Hybrid Optimization for Cluster‐Based Routing Protocol in Information-Centric Wireless Sensor Networks for IoT Based Mobile Edge Computing

Wireless Personal Communications - In present days, the utilization of mobile edge computing (MEC) and Internet of Things (IoT) in mobile networks offers a bottleneck in the evolving technological...     

A 3-D computational fluid dynamics model for forced air cooling of eggs placed in trays

Freshly laid shell eggs must be cooled quickly for controlling Salmonella Enteritidis (SE) growth. To fulfill a research need identified by Food Safety and Inspection Service (FSIS), a 3-D computational fluid dynamics (CFD) model was developed to predict the temperature of eggs placed on a tray (6 rows × 5 columns) under forced air cooling. The continuity, momentum, and energy equations were solved along with standard k − ε turbulence model using PHOENICS software. The model was validated by conducting experiments in a wind tunnel at various air temperatures (7-11 °C) and velocities (0.3-0.7 m/s). Root mean square error for predicting yolk temperatures was within 1 °C. Finally, the CFD model was integrated with a microbial growth model to estimate the risk of SE growth during cooling. This model can be incorporated into the FSIS risk assessment model for more accurate estimation of SE risk in shell eggs.     

Application of a weakly compressible smoothed particle hydrodynamics multi-phase model to non-cohesive embankment breaching due to flow overtopping

The subject of present study is the application of mesh free Lagrangian two-dimensional non-cohesive sediment transport model applied to a two-phase flow over an initially trapezoidal-shaped sediment embankment. The governing equations of the present model are the Navier-Stocks equations solved using Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) method. To simulate the movement of sediment particles, the model considers a powerful two-part technique; when the sediment phase has rigid behavior, only the force term due to shear stress in the Navier-Stokes equations is used for simulation of sediment particles’ movement. Otherwise, all the Navier-Stokes force terms are used for transport simulation of sediment particles. In the present model, the interactions between different phases are calculated automatically, even with considerable difference between the density and viscosity of phases. Validation of the model is performed using simulation of available laboratory experiments, and the comparison between computational results and experimental data shows that the model generally predicts well the flow propagation over movable beds, the induced sediment transport and bed changes, and temporal evolution of embankment breaching.     

Summation and routing on a partitioned optical passive stars network with large group size

In a partitioned optical passive stars (POPS) network, n=dg processors are divided into g groups of d processors each, and such a POPS network is denoted by POPS(d,g). There is an optical passive star (OPS) coupler between every pair of groups. Hence, a POPS(d,g) requires g/sup 2/ couplers. It is likely that, in a practical system, the number of couplers will be less than the number of processors, i.e., d>/spl radic/n>g and the number of groups will be smaller than the number of processors in a group. Hence, it is important to design fast algorithms for basic operations on such POPS networks with large group size. We present fast algorithms for data sum, prefix sum, and permutation routing on a POPS(d,g) such that d>/spl radic/n>g. Our data sum and prefix sum algorithms improve upon the best known algorithms for these problems designed by Sahni (2000). Permutation routing can be solved on a POPS network by simulating a hypercube sorting algorithm. Our algorithm for permutation routing is more efficient compared to this simulated hypercube sorting algorithm.