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Two-dimensional (2D) numerical experiments are performed to investigate the flow instabilities and mixing of different nonisothermal counterflowing jets in a passive-mixer. The fluid is modeled as a binary mixture with thermal and solutal buoyancy effects considered through the Boussinesq approximation. The streams are arranged in a thermal and solutal buoyancy aiding configuration. Computations are carried out for three different ratios of the upper jet bulk velocity to the lower jet bulk velocity (VR), namely, VR = 0.5, 1.0, and 2. Within the parametric domain of RiT and RiC defined by region (RiT + RiC) ≤ 3, the instability causing transition from steady to unsteady flow regime is observed for VR = 1 and 2, while no transition is found to occur at VR = 0.5. Using Landau theory, it is established that the transition from steady to unsteady flow regime is a supercritical Hopf bifurcation. A complete regime map identifying the steady and unsteady flow regimes, within the parametric space of this study, is obtained by plotting the neutral curves of RiC and RiT (obtained using Landau theory) for different values of VR. Proper orthogonal decomposition (POD) analysis of the unsteady flows at VR = 1 establishes the presence of standing waves. However, for VR = 2, the presence of degenerate pairs in the POD eigenspectrum ascertains the presence of traveling waves in the unsteady flows. The standing wave unsteady flow mode is found to yield the highest rate of mixing.

Nylons are one of the most successful commercialized polymers and can also be made to have ferroelectric properties. However, use of nylons in microelectronic devices like ferroelectric field-effect transistors has proven to be challenging due to the difficulty in achieving ferroelectric thin films by solution processing. In this work, we present ferroelectric field-effect transistor (FeFET) memory with a ferroelectric nylon-11 gate. Water quenching allows for the fabrication of ultra-smooth ferroelectric nylon-11 thin films. A bottom-gate top-contact (BGTC) FeFET is successfully demonstrated with a p-type semiconducting polymer, poly(triaryl amine) (PTAA), as a channel. The nylon-11 FeFET shows reliable memory functionality. The demonstration of nylon-11 based FeFETs makes nylons a promising material for applications in organic electronics, such as flexible devices, electronic textiles and biomedical devices.

Doping-free transfer of graphene produced by catalytic chemical vapor deposition (CVD) on copper foil, is still a technical challenge since unintentional doping of the transferred graphene layer yields an uncontrolled shift of Dirac point in graphene-based field-effect transistors (FETs). Typically, CVD graphene is released from the growth template by etching of the template, i.e. copper. During the etching process, ions adhere to the graphene layer resulting in unintentional doping. We demonstrate that washing a CVD graphene layer in an aqueous ammonia flow bath after etching copper, removes the majority of the unintentional dopants. FETs fabricated from graphene after washing in DI-water display a large scattering in Dirac bias with lowered mobility. In contrast, FETs from graphene that is washed in ammonia furnish better performance with high geometrically normalized mobility exceeding 2.4 × 104 cm2 V−1 s−1, balanced transport and a Dirac voltage near zero. We attribute the improved FET behavior to effective removal of the ions with a typical density of 4 × 1012 cm−2 from the graphene layer.

Numerical experiments performed for double diffusive impinging jets in a passive mixture with wall insulation to establish the effect of Reynolds number on their mixing. Value of Reynolds numbers considered are 100, 200 and 300. Thermal and concentration based Richardson numbers fixed at 1.0, whereas Prandtl number, Schmidt number to 0.7 and 0.8 respectively. Flow at Re = 100 is steady whereas for Re = 200 and 300, it is unsteady with vortex-shedding. Re = 100 and Re = 300 show better thermal mixing, whereas for Re = 300, better physical mixing is achieved. Re = 200 is least thermally and physically mixed.

Low power density of polymer piezoelectric nanogenerators is a major hurdle for their application as a potential mode of powering wearable and portable electronic devices. To increase the efficiency, here we suggest use of porous piezoelectric poly (vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE)) nanofibers. However, designing a process that allows introduction of pores in the nanometric fibers with a diameter of only several 100 nm, is highly challenging due to the intricate physics of polymer/solvent/anti-solvent interactions. Realization of the porous nanofibers would be a breakthrough in the field of piezoelectric nanogenerators. We presents an elegant approach based on the thermodynamics of polymer solutions to tailor porosity in P(VDF-TrFE) nanofibers. By adding a conscious amount of water, carefully chosen as non-solvent based on the ternary phase diagram of P(VDF-TrFE)/water/solvent, we intentionally induce liquid-phase demixing, which leads to formation of nanopores in the electrospun nanofiber. By calculating the mean composition trajectories, we predict and explain formation of the pores in the nanofibers, and show how little variations in initial water content substantially influences fiber porosity. Nanogenerators based on the porous electrospun P(VDF-TrFE) nanofibers show output power that systematically increases with porosity (with 500 times increase in output power for 45% porous fibers). The enhanced output is due to the reduced effective dielectric permittivity of the nanofibers. We unambiguously show that the voltage generation in nanofibers is of the same origin as in neat piezoelectric P(VDF-TrFE) films and is due to the relaxation of segments within the restricted amorphous phase. Understanding how to form nanopores, would have a major contribution to other fields, ranging from nanoporous membranes, as well as porous polymer structures for triboelectric nanogenerators.

Despite the realization of ferroelectricity in the δ-phase of poly(vinyleden difluoride) (PVDF) nearly four decades ago, the dynamics of polarization switching has not been studied yet. Here, we unravel the polarization switching mechanism as a one-dimensional process that is nucleated by a 90° rotation of a CH

Viruses cause a variety of diseases in humans and other organisms. The most important defense mechanism against viral infections is initiated when the viral genome is sensed by host proteins, and this results in interferon production and pro-inflammatory cytokine responses. The sensing of the viral genome or its replication intermediates within host cells is mediated by cytosolic proteins. For example, cGAS and IFI16 recognize non-self DNA, and RIG-I and MDA5 recognize non-self RNA. Once these sensors are activated, they trigger a cascade of reactions activating downstream molecules, which eventually results in the transcriptional activation of type I and III interferons, which play a critical role in suppressing viral propagation, either by directly limiting their replication or by inducing host cells to inhibit viral protein synthesis. The immune response against viruses relies solely upon sensing of viral genomes and their downstream signaling molecules. Although DNA and RNA viruses are sensed by distinct classes of receptor proteins, there is a possibility of overlap between the viral DNA and viral RNA sensing mechanisms. In this review, we focus on various host sensing molecules and discuss the associated signaling pathways that are activated in response to different viral infections. We further highlight the possibility of crosstalk between the cGAS-STING and the RIG-I-MAVS pathways to limit viral infections. This comprehensive review delineates the mechanisms by which different viruses evade host cellular responses to sustain within the host cells.

Polymeric nanocomposite thin films of magnetic nanoparticles blended with the ferroelectric polymer poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) are promising candidates for multiferroic applications. To date, only thick-film multiferroic nanocomposites have been reported. Fabrication of nanocomposite thin films along with the study of the ferroic properties with magnetic nanoparticle loading is crucial for the realization of functional devices. However, systematic studies, and in particular the dynamic of ferroelectric polarization switching and a solid understanding of the microstructure formation in thin films, are still missing. Here, we present solution-processed P(VDF-TrFE):magnetic nanoparticle thin films for multiferroic applications, wherein the ferroic properties, polarization switching dynamic, and the microstructure formation are studied as a function of nanoparticle loading. Our results demonstrate that as the nanoparticle loading increases, the ferroelectric polarization of t...

This work finds its motivation in heat exchanger design and flow control. Flow-induced vibration is studied numerically for combined vortex-induced vibrations and vortex-induced rotations of a horizontally positioned elliptic cylinder. The aspect ratio is taken as 2, and the value of reduced velocities ([Formula: see text]) considered for the present simulation is between 2 and 12. The body can have to and fro motions in a transverse (y) direction, in-line (x) direction as well as in azimuthal ([Formula: see text]) direction, which provides three degrees of freedom (DOF) to the body. It is found that for one-DOF (y-direction only) and two-DOF (y and x directions) cases, lock-in regions are the same while it is wider for the case of the three-DOF system. With the rotational DOF, y-directional motion is amplified and when it is compared with the one-DOF and two-DOF cases, difference in peak amplitude is about 30%. The rotational response reaches a maximum value within the synchronization regime, and the frequency behavior of rotational and transverse oscillations is showing the same characteristics. The phase difference is plotted to check their synchronization with respective forces and moments. For all DOFs and [Formula: see text], synchronized or desynchronized regions, 2S mode of vortex shedding was observed. For one-DOF and two-DOF cases, the transverse vibrational frequency ratio ([Formula: see text]) becomes equal to unity for the range [Formula: see text]. For three-DOF, [Formula: see text] and rotational frequency ratio ([Formula: see text] become close to the unity for [Formula: see text]. The three-DOF system shows smaller wake width and vortex formation length whereas the vortex strength is maximum.

We have developed a method to solution process strongly hydrogen-bonded odd nylons into ferroelectric thin films., Ferroelectricity, a bistable ordering of electrical dipoles in a material, is widely used in sensors, actuators, nonlinear optics, and data storage. Traditional ferroelectrics are ceramic based. Ferroelectric polymers are inexpensive lead-free materials that offer unique features such as the freedom of design enabled by chemistry, the facile solution-based low-temperature processing, and mechanical flexibility. Among engineering polymers, odd nylons are ferroelectric. Since the discovery of ferroelectricity in polymers, nearly half a century ago, a solution-processed ferroelectric nylon thin film has not been demonstrated because of the strong tendency of nylon chains to form hydrogen bonds. We show the solution processing of transparent ferroelectric thin film capacitors of odd nylons. The demonstration of ferroelectricity, as well as the way to obtain thin films, makes odd nylons attractive for applications in flexible devices, soft robotics, biomedical devices, and electronic textiles.

In this paper, a simple method is presented for measurement of power frequency deviations. A phase locked loop (PLL) is used to multiply the signal under test by a factor of 100. The number of pulses in this pulse train signal is counted over a stable known period, using decade driving assemblies (DDAs) and flip-flops. These signals are combined using logic gates and then passed through decade counters to give a unique combination of pulses or levels, which are further encoded. These pulses are equally suitable for both control applications and display units. The experimental circuit developed gives a resolution of 1 Hz within the measurement period of 20 ms. The proposed circuit is also simulated in Verilog Hardware Description Language (VHDL) and implemented using Field Programing Gate Arrays (FPGAs). A Mixed signal Oscilloscope (MSO) is used to observe the results of FPGA implementation. These results are compared with the results of the proposed circuit of discrete components. The proposed system is useful for frequency deviation measurement and control in power systems.

Electronic textiles and functional fabrics are among the key constituents envisioned for wearable electronics applications. For e‐textiles, the challenge is to process materials of desired electronic properties such as piezoelectricity into fibers to be integrated as wefts or wraps in the fabrics. Nylons, first introduced in the 1940s for stockings, are among the most widely used synthetic fibers in textiles. However, realization of nylon‐based e‐textiles has remained elusive due to the difficulty of achieving the piezoelectric phase in the nylon fibers. Here, piezoelectric nylon‐11 fibers are demonstrated and it is shown that the resulting fibers are viable for applications in energy harvesting from low frequency mechanical vibrations and in motion sensors. A simulation study is presented that elucidates on the sensitivity of the nylon‐11 fibers toward external mechanical stimuli. Moreover, a strategy is proposed and validated to significantly boost the electrical performance of the fibers. Since a large fraction of the textile industry is based on nylon fibers, the demonstration of piezoelectric nylon fibers will be a major step toward realization of electronic textiles for applications in apparels, health monitoring, sportswear, and portable energy generation. Alexander von Humboldt Foundation Max Planck Institute for Polymer Research National University of Science and Technology

In this study, experimental research is carried out on two different class of refrigerants at three varied ambient conditions viz. (30°C, 35ºC and 40ºC) and three different air velocities viz. (1.25, 1.00, 0.75 m/s) in air cooled and evaporative cooled condenser. The first class is of low temperature refrigerant (R-134a) and the second is of high temperature refrigerant (R-410a). The results described that COP of high temperature refrigerant is greater than that of low temperature refrigerant. The COP increased with increasing air speed in air cooled and evaporative cooled condenser and decreased with increasing the ambient temperatures. For a fixed ambient temperature and air velocity, the COP of R-410a turned out to be greater than the COP of R-134a.Thus proving that high temperature refrigerant is better in performance than low temperature refrigerant.

Since the introduction of the European Working Time Directive, specialist registrars arguably contribute less to clinical service. The purpose of this study was to broadly quantify the service contribution of specialist registrars across a range of specialties and their value to an NHS organisation. A questionnaire-based survey of the clinical activities of specialist registrars in a large NHS trust was undertaken. Simple costing analyses of this ­clinical activity were performed. Responses from 66 specialist registrars in 24 specialties showed an average of 51% overall clinical autonomy. Trainees attended an average of 2.7 outpatient clinics per week and spent 3.5 sessions a week doing ward work. Medical trainees took more referrals and attended more clinics. An analysis of costings suggested that surgical trainees might have generated around £700,000 income per year for the trust. Overall, specialist registrars make a substantial contribution to NHS clinical service and are cost-effective.

Organic bistable diodes based on phase-separated blends of ferroelectric and semiconducting polymers have emerged as promising candidates for non-volatile information storage for low-cost solution processable electronics. One of the bottlenecks impeding upscaling is stability and reliable operation of the array in air. Here, we present a memory array fabricated with an air-stable amine-based semiconducting polymer. Memory diode fabrication and full electrical characterizations were carried out in atmospheric conditions (23 °C and 45% relative humidity). The memory diodes showed on/off ratios greater than 100 and further exhibited robust and stable performance upon continuous write-read-erase-read cycles. Moreover, we demonstrate a 4-bit memory array that is free from cross-talk with a shelf-life of several months. Demonstration of the stability and reliable air operation further strengthens the feasibility of the resistance switching in ferroelectric memory diodes for low-cost applications.

Two -dimensional interactio n of two opposing jets/streams of different fluids in a channel is numerically investigated in the mixed convection regime. The buoyancy forces due to temperature difference (thermal buoyancy) as well as inherent differences in the densities of the two fl uid streams (intrinsic buoyancy) have been considered through Boussinesq approximation. In addition to the Prandtl (Pr) , Schmidt (Sc) and the Reynolds (Re) numbers, the two buoyancy forces (thermal and intrinsic) give rise to thermal and intrinsic Richard son numbers, Ri t and Ri c, respectively as the important dimensionless numbers governing the problem . As the two fluid streams are of inherently different densities, two configurations are considered: i) the upper stream comprising of heavier fluid at low er temperature and lower stream comprising of lighter fluid at higher temperature (aiding buoyancy forces) - Case I and ii) the upper stream comprising of lighter fluid at lower temperature and lower stream comprising of heavier fluid at higher temperature (opposing buoyancy forces) - Case II. For both the cases simulations have been carried out for three pairs of Richardson numbers (Ri t and Ri c), namely, (0.3, 0.2), (0.5, 0.2) and (0.2, 0.5) respectively. The values of Pr, Sc and Re is fixed at 0.7, 0.8 an d 200 respectively. In case I, global flow structure is not very sensitive to Richardson numbers within the range of Ri t, Ri c chosen in present study, while flow structure is very sensitive in case II. Symmetry is obtained for all combinations of Ri t, Ri c chosen in this study for case I, where as asymmetries are obtained is case II because of comparable values of Ri t, Ri c. Steady state for all simulations are attained. Pumping pressure for case I is lower than for case II for all values of Ri t, Ri c taken u p in the present study. Almost 90 % mixing is achieved in dimensionless length range of 40 -60. Mixing characteristic is more sensitive to configuration in central region rather than in whole channel.

Risk assessment and practicality of the process is always a challenging task as it requires a considerable time and effort to perform a quantitative risk assessment. Most of the risk assessment models in use requires a holistic approach and are not flexible to be applied at smallest of the operations and activities. Health risk register provides an opportunity to take the process a step ahead towards more practicality and flexibility. It takes the risk assessment to the grass root level of the operations.

Introduction and Objectives The Gene Xpert ® MTB/RIF test has been validated in sputum samples, facilitating rapid mycobacterium tuberculosis (MTB) diagnosis with improved sensitivity compared to smear alone. Its utility in bronchoalveolar lavage (BAL) samples, in a low prevalence setting, is unclear. Our objective was to examine the sensitivity of the Xpert ® test in BAL samples and evaluate its use as a rapid diagnostic test in non-productive or smear negative patients undergoing bronchoscopy. Methods We conducted a retrospective analysis of all culture-proven MTB samples acquired by BAL between 01.08.2009 and 01.06.2013, which were also sent for the Xpert ® test, n = 38. We assessed the proportion of Xpert ® MTB positive samples and compared these results with smear status and time to culture positivity. Results 26/38 of the culture-proven cases sent for analysis were MTB Xpert ® positive, giving a sensitivity (if culture is taken as the 9gold standard9) of 68%. 17/38 samples were smear positive. Of the 21 smear negative/culture positive samples, 43% were MTB Xpert ® positive. All smear positive cases were Xpert ® positive. The Xpert ® positive samples had a lower mean time to positivity: 11.2 days vs. 17.2 days for Xpert ® negative samples. There was one case of rifampicin resistance correctly identified by Gene Xpert®, giving a lead time of 28 days vs. culture sensitivity. Incidentally 4 additional Xpert ® positive samples were identified which were BAL culture negative, all in patients with clinically likely MTB, one of whom went on to culture MTB from sputum, and one of whom had necrotising granulomas on subsequent endobronchial ultrasound-guided transbronchial needle aspiration. Conclusions To our knowledge this is the largest series reported of MTB culture positive BAL samples analysed using the Xpert ® MTB/RIF assay. This data supports the use of Xpert ® in the diagnosis of pulmonary MTB in BAL fluid, with a sensitivity of 68% when compared to MTB culture, adding additional value to simple smear and early detection of rifampicin resistance. In fact, the true sensitivity may well be higher given the cases detected exclusively by Xpert®.

Complexes of homocystine, [-SCH2CH2CH(NH2)COOH]2, have been prepared with Cr(II), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) chlorides. They have been characterized by elemental analyses, diffuse reflectance spectra and magnetic susceptibility measurements. The elemental analyses indicates a 1:1 metal: ligand ratio. The divalent metal ions are coordinated through all the donor sites of the amino acid while trivalent iron seems to be coordinated only through nitrogen and oxygen with bridging chlorine atoms. The spectral and magnetic data suggest an octahedral metal environment in all these complexes except for Zn(II) and Cd(II).

A few transition metal complexes of 2-thiobarbituric acid (TBA) have been synthesized and characterized by chemical analyses, i.r.- and reflectance spectroscopic studies and magnetic susceptibility measurements. On the basis of these studies Cu(II), Cd(II) and Pd(II) complexes have been proposed to have square-planar geometry While those of Mn(II), Fe(III), Co(II), Ru(III), Rh(III), Ir(III) and Pt(IV) were found to be octahedral. Mn(II), Cu(II), Co(II) and Fe(III) complexes are magnetically subnormal. TBA has been found to act as a bidentate or quadridentate ligand. The sulphur atom in no case has been claimed as a coordination site. Metal ligand stretching frequencies occur in the range 175–270 cm−1 for first row transition metals and Cd(II), which follow the Irwing-Williams sequence of metal ions

The synthesis and characterization of two new ligands, potassium hydrotris (5-nitroindazolyl) borate (2) have been achieved. Complexes of (1) with the first row divalent transition metal ions chromium through copper, as well as with palladium and platinum have been prepared, while for (2) complexes with divalent nickel, palladium and tetravalent platinum have been synthesized. All these complexes were formed in 1:2 metal:ligand molar ratio excepting for nickel with ligand (2) which yields a 1:1 complex. These complexes were all non-electrolytes in DMF, the only solvent in which they were soluble. Magnetic susceptibility measurements and ligand field spectral studies indicate an octahedral geometry for all the complexes excepting those of platinum (II) and palladium (II) which have been shown to have a square planar geometry. Some ligand field parameters have been evaluated for a few of these complexes with the help of Tanabe-Sugano diagrams.

The potassium salts of the three new potential chelating ligands dihydrobis-, hydrotris- and tetrakis(6-nitro-indazoly1)borate anions have been synthesized by refluxing potassium borohydride and 6-nitroindazole in DMF in the appropriate molar ratio. These salts have been used to form complexes with the 3d transition metal ions vanadium through copper. The complexes of dihydrobis(6-nitroindazoly1)borate anion with V(III) and Fe(III) are octahedral, whereas Mn(II), Co(II), Ni(II) and Cu(II) complexes have tetrahedral geometry. The Cr(II) complex has been observed to be tetragonally distorted. The hydrotris(6-nitroindazoly1)borate anion gave rise to only octahedral complexes of the above metal ions except for Cr(II) and Cu(II) which gave rise to complexes with tetragonally distorted octahedral geometry. The tetrakis(6-nitroindazoly1)-borate anion is found to be a substituted variant of the hydrotris ligend.

The synthesis and characterization of a novel ligand, dihydrobis(5-nitroindazolyl) borate, and several of its complexes with transition metal ions have been carried out. It has been found that the ligand is uninegative, and forms octahedral complexes of the metal ions V(III), Fe(III), Pt(IV), Cr(II), Mn(II) and Co(II). The Ni(II), Cu(II) and Pd(II) ions form square-planar complexes whereas the Cu(I) ion yields a tetrahedral mixed ligand complex involving a dihydrobis(5-nitroindazolyl) borate and two 5-nitroindazolyl moieties. The Fe(III) complex has been found to undergo reduction when the solution is left to stand for about a month giving the Fe(II) complex in the form of a stable solid compound.