Effects of mixing strategy on catalyst‐assisted reactive blending of polycarbonate and polyethylene terephthalate

Reactive melt mixing of polycarbonate (PC) and polyethylene terephthalate (PET) blends with constant composition of 80:20 in the presence of a freshly added catalyst was conducted through a two‐step method. At first, PC and PET underwent premixing and melt mixed in the absence of a fresh catalyst. Then, mixing continued with catalyst addition under the same previous condition. The effects of varied premixing times from 1 to 5 min and mixing intensity at rotor speeds of 30 and 50 rev/min (rpm) were separately evaluated in transesterification reaction. The results of solubility analysis showed that the longer premixing time and the higher mixing rate enhanced the rate and extension of reaction. Fourier transform infrared (FTIR) spectroscopy and thermal analysis by differential scanning calorimetry were conducted on specimens on the basis of solubility separations. The height ratio of carbonyl group peaks of PC and PET phases were calculated for their corresponding FTIR spectra. The height ratio for PET showed a good correlation with solubility data. Moreover, crystallinity of PET phase was influenced by the reaction which was analyzed by solubility parameters. J. VINYL ADDIT. TECHNOL., 25:127–133, 2019. © 2018 Society of Plastics Engineers     

Correlation,Kalman filter and adaptive fast mean shift based heuristic approach for robust visual tracking

Correlation tracker is computation intensive (if the search space or the template is large), has template drift problem, and may fail in case of fast maneuvering target, rapid changes in its appearance, occlusion suffered by it and clutter in the scene. Kalman filter can predict the target coordinates in the next frame, if the measurement vector is supplied to it by a correlation tracker. Thus, a relatively small search space can be determined where the probability of finding the target in the next frame is high. This way, the tracker can become fast and reject the clutter, which is outside the search space in the scene. However, if the tracker provides wrong measurement vector due to the clutter or the occlusion inside the search region, the efficacy of the filter is significantly deteriorated. Mean-shift tracker is fast and has shown good tracking results in the literature, but it may fail when the histograms of the target and the candidate region in the scene are similar (even when their appearance is different). In order to make the overall visual tracking framework robust to the mentioned problems, we propose to combine the three approaches heuristically, so that they may support each other for better tracking results. Furthermore, we present novel method for (1) appearance model updating which adapts the template according to rate of appearance change of target, (2) adaptive threshold for similarity measure which uses the variable threshold for each forthcoming image frame based on current frame peak similarity value, and (3) adaptive kernel size for fast mean-shift algorithm based on varying size of the target. Comparison with nine state-of-the-art tracking algorithms on eleven publically available standard dataset shows that the proposed algorithm outperforms the other algorithms in most of the cases.     

Petri Net modelling approach for analysing the behaviour of Wnt/ β ‐catenin and Wnt/ Ca2+ signalling pathways in arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart muscle disease that may result in arrhythmia, heart failure and sudden death. The hallmark pathological findings are progressive myocyte loss and fibro fatty replacement, with a predilection for the right ventricle. This study focuses on the adipose tissue formation in cardiomyocyte by considering the signal transduction pathways including Wnt/ β ‐catenin and Wnt/Ca²⁺ regulation system. These pathways are modelled and analysed using stochastic petri nets (SPN) in order to increase our comprehension of ARVC and in turn its treatment regimen. The Wnt/ β ‐catenin model predicts that the dysregulation or absence of Wnt signalling, inhibition of dishevelled and elevation of glycogen synthase kinase 3 along with casein kinase I are key cytotoxic events resulting in apoptosis. Moreover, the Wnt/Ca²⁺ SPN model demonstrates that the Bcl2 gene inhibited by c‐Jun N‐terminal kinase protein in the event of endoplasmic reticulum stress due to action potential and increased amount of intracellular Ca²⁺ which recovers the Ca²⁺ homeostasis by phospholipase C, this event positively regulates the Bcl2 to suppress the mitochondrial apoptosis which causes ARVC.Inspec keywords: molecular biophysics, enzymes, cancer, muscle, Petri nets, cellular biophysics, bioelectric potentials, biomembranes, tumours, cardiology, genetics, biochemistry, calciumOther keywords: heart failure, sudden death, hallmark pathological findings, progressive myocyte loss, fibro fatty replacement, adipose tissue formation, signal transduction pathways, Ca²⁺ regulation system, stochastic petri nets, ARVC, $β‐catenin model, Wnt signalling, glycogen synthase kinase 3, Bcl2 gene, c‐Jun N‐terminal kinase protein, petri Net modelling approach, Ca²⁺ signalling pathways, arrhythmogenic right ventricular cardiomyopathy, inherited heart muscle disease, Ca²⁺ SPN model, Ca     

Surface and bulk investigation of ZSM5 and Al-MCM-41 using synchrotron XPS, XANES, and hexane cracking

We present a comparative study of ZSM5 and Al-MCM-41 catalysts using spectroscopic and chemical techniques. The analysis of conventional and synchrotron XPS spectra of these catalysts reveals the presence of a topmost surface-related Si peak in addition to the bulk peak. XANES results suggest structural modification upon heating Al-MCM-41 at 500 °C. Depth-resolved XPS data show Al depletion from the surface of Al-MCM-41 in contrast to surface enrichment of Al in ZSM5. These surface modifications could be one of the reasons for the weak acidity of Al-MCM-41 in chemical reactions such as hexane cracking at different temperatures.     

In vitro antibacterial activity of ceftazidime,unlike ciprofloxacin,improves in the presence of ZnO nanofluids under acidic conditions

The development of antibiotic resistance among hospital pathogens has provided a great need for new antimicrobial agents. Zinc oxide nanoparticles (ZnO NPs) in combination with various antibiotics can act as a reducing agent for antibiotic resistance. The aim of this study was to investigate the influence and the mechanism of ZnO NPs on the antimicrobial activity of ciprofloxacin (CP) and ceftazidime (CAZ) against Enterococcus faecalis (E. faecalis) and Acinetobacter baumannii (A. baumannii) bacteria in acidic conditions (pH 5.5). ZnO NPs were synthesised using the solvothermal method and characterised. The MIC90 value of ZnO NPs against A. baumannii was 0.25 mg ml⁻¹ and its highest growth‐inhibitory activity was observed at 0.125 mg ml⁻¹ for E. faecalis. The Fourier transform infrared spectroscopy spectra of ZnO NPs treated with antibiotics showed the interaction between ZnO NPs and each of the two antibiotics. ZnO NPs at a sub‐inhibitory concentration had no effect on the antibacterial activity of CP and CAZ against E. faecalis and CP against A. baumannii. The action mechanism of ZnO NPs for enhancing the antibacterial efficacy of CAZ against A. baumannii was evaluated. ZnO NPs caused to increase in the antibacterial activity of CAZ against A. baumannii, possibly through the release of Zn²⁺ and increasing of membrane permeability.Inspec keywords: nanofluidics, antibacterial activity, drugs, nanoparticles, nanomedicine, microorganisms, pH, zinc compounds, II‐VI semiconductors, wide band gap semiconductors, semiconductor growth, X‐ray diffraction, light scattering, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, ultraviolet spectra, visible spectra, DNA, molecular biophysics, biochemistry, atomic absorption spectroscopy, membranes, permeability, nanofabricationOther keywords: in vitro antibacterial activity, ceftazidime, nanofluids, acidic conditions, antibiotic resistance, hospital pathogens, antimicrobial agents, zinc oxide nanoparticles, reducing agent, antimicrobial activity, ciprofloxacin, Enterococcus faecalis bacteria, Acinetobacter baumannii bacteria, pH, solvothermal method, X‐ray diffraction, dynamic light scattering, ultraviolet‐visible spectrum, scanning electron microscopy, transmission electron microscopy, MIC90 value, growth‐inhibitory activity, Fourier transform infrared spectroscopy, subinhibitory concentration, reactive oxygen species measurement, DNA fragmentation, atomic absorption spectroscopy, SEM, membrane permeability, glycerol‐ammonium citrate. mixture, ZnO     

Reliability evaluation of a natural circulation system

This paper discusses a reliability study performed with reference to a passive thermohydraulic natural circulation (NC) system, named TTL-1. A methodology based on probabilistic techniques has been applied with the main purpose to optimize the system design. The obtained results have been adopted to estimate the thermal-hydraulic reliability (TH-R) of the same system.A total of 29 relevant parameters (including nominal values and plausible ranges of variations) affecting the design and the NC performance of the TTL-1 loop are identified and a probability of occurrence is assigned for each value based on expert judgment. Following procedures established for the uncertainty evaluation of thermal-hydraulic system codes results, 137 system configurations have been selected and each configuration has been analyzed via the Relap5 best-estimate code. The reference system configuration and the failure criteria derived from the “mission” of the passive system are adopted for the evaluation of the system TH-R.Four different definitions of a less-than-unity “reliability-values” (where unity represents the maximum achievable reliability) are proposed for the performance of the selected passive system. This is normally considered fully reliable, i.e. reliability-value equal one, in typical Probabilistic Safety Assessment (PSA) applications in nuclear reactor safety. The two ‘point’ TH-R values for the considered NC system were found equal to 0.70 and 0.85, i.e. values comparable with the reliability of a pump installed in an “equivalent” forced circulation (active) system having the same “mission.” The design optimization study was completed by a regression analysis addressing the output of the 137 calculations: heat losses, undetected leakage, loop length, riser diameter, and equivalent diameter of the test section have been found as the most important parameters bringing to the optimal system design and affecting the TH-R.As added values for this work, the comparison has been made between results from this study and results from a previous analysis where the same methodology was adopted for the evaluation of the TH-R of a different passive system named Isolation Condenser (IC). The comparison shows that the current single-phase NC system is ‘more reliable’ than the two-phase IC system. This constitutes a proof of qualification and of consistency for the adopted methodology.     

Nonkinetic changes in heat-treated glasslike carbons part I: Pore size and bulk dimensions

Small-angle X-ray scattering measurements have been used to characterize the radius of gyration R_g of the pores in a glasslike carbon heat treated between 1000 and 2800°C for periods up to 150 hours. Measurements were also made of the irreversible bulk dimensional changes Δl. In both cases, a nonkinetic increase occurs when the heat treatment temperature is increased stepwise to a higher value. The relative changes ΔR_g/R_g and Δl/l exhibit a similar three-region behavior: an initial increase with the annealing temperature up to 1600°C, a plateau up to about 2200°C, and thereafter an increase again. However, the maximum dilatation Δl/l is scarcely 3% whereas the increase in ΔR_g/R_g is twofold. The first region is attributed to a gas pressure mechanism, and the highest-temperature region results from strain relief due to the mismatch of the thermal expansion coefficients in the directions perpendicular and parallel to the layers in graphitic materials. The intermediate region is explained by a combination of both mechanisms.     

CF4和惰性气体混合物的输运性质的计算

The present work is concerned with determining the viscosity, diffusion, thermal diffusion factor and thermal conductivity of five equimolar binary gas mixtures including: CF4-He, CF4-Ne, CF4-Ar, CF4-Kr, CF4-Xe from the principle of corresponding states of viscosity by the inversion technique. The Lennard-Jones (12-6) model potential is used as the initial model potential. The calculated interaction potential energies obtained from the inversion procedure is employed to reproduce the viscosities, diffusions, thermal diffusion factors, and thermal conductivities. The accuracies of the calculated viscosity and diffusion coefficients were 1% and 4%, respectively.     

Nanoscopic volume trapping and transportation using a PANDA ring resonator for drug delivery

A novel design of nanoscopic volume transmitter and receiver for drug delivery system using a PANDA ring resonator is proposed. By controlling some suitable parameters, the optical vortices (gradient optical fields/wells) can be generated and used to form the trapping tools in the same way as the optical tweezers. By using the intense optical vortices generated within the PANDA ring resonator, the nanoscopic volumes (drug) can be trapped and moved (transport) dynamically within the wavelength router or network. In principle, the trapping force is formed by the combination between the gradient field and scattering photons, which is reviewed. The advantage of the proposed system is that a transmitter and receiver can be formed within the same system (device), which is called a transceiver, which is available for nanoscopic volume (drug volume) trapping and transportation (delivery).