619 research outputs found
Flame retardant coating on cotton fabric with phosphorus containing polymeric film by admicellar polymerization
In this study, 2-methacryloyloxyethyl phosphorylcholine monomer has been polymerized using azobis-isobutyronitrileinitiator on the surface of cotton fabric by admicellar polymerization with the assistance of anionic surfactant(dodecylbenzenesulphonic acid sodium salt) along with NaCl as electrolyte. The polymeric film formed on cotton surfacehas been characterized by FTIR and SEM. FTIR spectrum shows additional bands at 1720 cm-1 (C=O str.), 1258 cm-1(P=O str.) and 1078 cm-1 (P ̶ O ̶ C str.) of phosphorus based polymer formed on cotton fabric. Thermal behaviour innitrogen atmosphere is also studied which shows that onset temperature of degradation of treated cotton fabric decreases by37 ÂșC and char yield increases by 21.7% at 600 ÂșC. The burning behaviour of treated cotton fabric is investigated by 45Âș autoflammability and limiting oxygen index tests. The pure cotton fabric burns the entire length of 15 cm sample in 11.8 s buttreated cotton fabric self-extinguishes in auto flammability test. The durability of treated cotton fabric has also been studiedup to two home launderings
Magnetic moments of the low-lying , resonances within the framework of the chiral quark model
The magnetic moments of the low-lying spin-parity ,
resonances, like, for example, ,
, as well as their transition magnetic moments, are
calculated using the chiral quark model. The results found are compared with
those obtained from the nonrelativistic quark model and those of unitary chiral
theories, where some of these states are generated through the dynamics of two
hadron coupled channels and their unitarization
Elastomer-based touch sensor: Visualization of tactile pressure distribution
© Springer Nature Switzerland AG 2019. This paper presents an elastomer-based tactile sensor that can sense the tactile information in the form of pressure distribution. Our proposed sensor uses a piece of coated elastomer with thin conical pins underneath as the touch medium. The elastomer consists of 91 pins arranged in a honeycomb pattern, each pin can be regarded as a tactile sensing element. They are spaced at 1.5 mm in x and y direction. Each tactile element transfers the applied pressure value into a circular image pattern which can be captured by a camera placed at the end of the sensor structure. The applied pressure over the sensing array can be computed by processing the area of each sensing element. MATLAB is used to process the received images relating the applied pressure to the activated pixels in each circular pattern of the tactile element, and further visualizing the pressure distribution on a reconstructed surface of the sensor. This paper presents the development principle and fabrication process of the proposed sensor. The experimental results have proven the viability of the sensing concept; the prototype sensor can effectively detect single-point touch caused by objects with different dimensions and multi-point touch interactions with a spacing of more than 2.5 mm
Fingerprint-enhanced capacitive-piezoelectric flexible sensing skin to discriminate static and dynamic tactile stimuli
nspired by the structure and functions of the human skin, a highly sensitive capacitiveâpiezoelectric flexible sensing skin with fingerprintâlike patterns to detect and discriminate between spatiotemporal tactile stimuli including static and dynamic pressures and textures is presented. The capacitiveâpiezoelectric tandem sensing structure is embedded in the phalange of a 3Dâprinted robotic hand, and a tempotron classifier system is used for tactile exploration. The dynamic tactile sensor, interfaced with an extended gate configuration to a common source metal oxide semiconductor field effect transistor (MOSFET), exhibits a sensitivity of 2.28âkPaâ1. The capacitive sensing structure has nonlinear characteristics with sensitivity varying from 0.25âkPaâ1 in the lowâpressure range (<100âPa) to 0.002âkPaâ1 in high pressure (â2.5âkPa). The output from the presented sensor under a closedâloop tactile scan, carried out with an industrial robotic arm, is used as latencyâcoded spike trains in a spiking neural network (SNN) tempotron classifier system. With the capability of performing a realâtime binary naturalistic texture classification with a maximum accuracy of 99.45%, the presented bioinspired skin finds applications in robotics, prosthesis, wearable sensors, and medical devices
Magnetic moments of the low-lying {1/2}^- octet baryon resonances
The magnetic moments of the negative parity octet resonances with spin {1/2}:
(1535), (1650), (1620), and (1690) have been
calculated within the framework of the chiral constituent quark model. In this
approach, the presence of the polarized pairs (or the meson cloud,
in other words) is considered by using the Lagrangian for Goldstone boson
emission from the constituent quarks. Further, the explicit contributions
coming from the spin and orbital angular momentum, including the effects of the
configurations mixing between the states with different spins, are obtained.
The motivation for these calculations comes from the recent interest in
experimental measurement of the magnetic moment of the
resonance and of similar calculations being done within lattice quantum
chromodynamics approaches. Our results can be compared with those expected to
come from these sources.Comment: 17 pages, 2 table
Octet magnetic moments and the Coleman-Glashow sum rule violation in the chiral quark model
Baryon octet magnetic moments when calculated within the chiral quark model,
incorporating the orbital angular momentum as well as the quark sea
contribution through the Cheng-Li mechanism, not only show improvement over the
non relativistic quark model results but also gives a non zero value for the
right hand side of Coleman-Glashow sum rule. When effects due to spin-spin
forces between constituent quarks as well as `mass adjustments' due to
confinement are added, it leads to an excellent fit for the case of p,
\Sigma^+, \Xi^o and violation of Coleman-Glashow sum rule, whereas in almost
all the other cases the results are within 5% of the data.Comment: 5 RevTeX pages, accepted for publication in PRD(Rapid Communication
SU(4) Chiral Quark Model with Configuration Mixing
Chiral quark model with configuration mixing and broken SU(3)\times U(1)
symmetry has been extended to include the contribution from c\bar c
fluctuations by considering broken SU(4) instead of SU(3). The implications of
such a model have been studied for quark flavor and spin distribution functions
corresponding to E866 and the NMC data. The predicted parameters regarding the
charm spin distribution functions, for example, \Delta c, \frac{\Delta
c}{{\Delta \Sigma}}, \frac{\Delta c}{c} as well as the charm quark distribution
functions, for example, \bar c, \frac{2\bar c}{(\bar u+\bar d)}, \frac{2 \bar
c}{(u+d)} and \frac{(c+ \bar c)}{\sum (q+\bar q)} are in agreement with other
similar calculations. Specifically, we find \Delta c=-0.009, \frac{\Delta
c}{{\Delta \Sigma}}=-0.02, \bar c=0.03 and \frac{(c+ \bar c)}{\sum (q+\bar
q)}=0.02 for the \chiQM parameters a=0.1, \alpha=0.4, \beta=0.7,
\zeta_{E866}=-1-2 \beta, \zeta_{NMC}=-2-2 \beta and \gamma=0.3, the latter
appears due to the extension of SU(3) to SU(4).Comment: 10 RevTeX pages. Accepted for publication in Phys. Rev.
dependence of the quark distribution functions in the CQM
Chiral constituent quark model with configuration mixing (\chiCQM_{{\rm
config}}) is known to provide a satisfactory explanation of the ``proton spin
problem'' and related issues. In order to enlarge the scope of \chiCQM_{{\rm
config}}, we have attempted to phenomenologically incorporate x-dependence in
the quark distribution functions. In particular, apart from calculating valence
and sea quark distributions q_{{\rm val}}(x) and \bar q(x), we have carried out
a detailed analysis to estimate the sea quark asymmetries \bar d(x)-\bar u(x),
\bar d(x)/\bar u(x) and \frac{\bar d(x)-\bar u(x)}{u(x)-d(x)} as well as spin
independent structure functions F_2^p(x)-F_2^n(x) and as
functions of . We are able to achieve a satisfactory fit for all the above
mentioned quantities simultaneously. The inclusion of effects due to
configuration mixing have also been examined in the case F_2^p(x)-F_2^n(x) and
F_2^n(x)/F_2^p(x) where the valence quark distributions dominate and it is
found that it leads to considerable improvement in the results. Further, the
valence quark structure has also be tested by extrapolating the predictions of
our model in the limit x \to 1 where data is not available.Comment: 20 pages, 7 figures. To appear in Eur. Phys. J.
Mechanism of single-spin asymmetries generation in the inclusive hadron processes
We discuss a nonperturbative mechanism for generation of the single-spin
asymmetries in hadron interactions. It is based on the chiral quark model
combined with unitarity and impact parameter picture and provides explanation
for the experimental regularities observed under the measurements of the spin
asymmetries.Comment: 20 pages, 7 figure
Ävrsta disperzija meloksikama: faktorijalno dizajnirani dozirani pripravak za gerijatrijsku populaciju
The objective of the present work was to improve the dissolution properties of the poorly water-soluble drug meloxicam by preparing solid dispersions with hydroxyethylcellulose (HEC), mannitol and polyethylene glycol (PEG) 4000 and to develop a dosage form for geriatric population. Differential scanning calorimetry, Xâray diffractometry, Fourier transform infrared spectroscopy and scanning electron microscopy were used to investigate the solid-state physical structure of the prepared solid dispersions. Higher in vitro dissolution of solid dispersions was recorded compared to their corresponding physical mixtures and the pure drug. PEG 4000 in 1:9 drug to carrier ratio exhibited the highest drug release (100.2%), followed by mannitol (98.2%) and HEC (89.5%) in the same ratio. Meloxicam-PEG 4000 solid dispersion was formulated into suspension and optimization was carried out by 23 factorial design. Formulations containing higher levels of methyl cellulose and higher levels of either sodium citrate or Tween 80 exhibited the highest drug release.Cilj rada bio je poboljĆĄati topljivost meloksikama u vodi pripravom Ävrstih disperzija s hidroksietilcelulozom (HEC), manitolom i polietilen glikolom 4000 (PEG 4000) te razviti dozirani pripravaka za gerijatrijsku populaciju. Za ispitivanje fiziÄke strukture pripravljenih Ävrstih disperzija koriĆĄtene su diferencijalna pretraĆŸna kalorimetrija, difraktometrija rentgentskim zrakama, FTIR i pretraĆŸna elektronska mikroskopija. Ävrste disperzije su u in vitro uvjetima pokazale bolju topljivost u odnosu na fiziÄku smjesu i Äistu ljekovitu tvar. Najbolje oslobaÄanje lijeka (100,2%). postignuto je iz disperzija s PEG 4000 (omjer ljekovite tvari i nosaÄa 1:9). Slijede manitol (98,2%) i HEC (89,5%) (isti omjer meloksikama i polimera). Ävrsta disperzija meloksikama s PEG 4000 prevedena je u suspenziju te optimirana 23 faktorijalnim dizajnom. Najbolje oslobaÄanje ljekovite tvari postignuto je iz pripravaka koji sadrĆŸe veÄi udio etilceluloze i natrijevog citrata, odnosno Tween 80
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