A New Phenomenon: Sub-Tg, Solid-State, Plasticity-Induced Bonding in Polymers

Polymer self-adhesion due to the interdiffusion of macromolecules has been an active area of research for several decades [70, 43, 62, 42, 72, 73, 41]. Here, we report a new phenomenon of sub-Tg, solid-state, plasticity-induced bonding; where amorphous polymeric films were bonded together in a period of time on the order of a second in the solid-state at ambient temperatures nearly 60 K below their glass transition temperature (Tg) by subjecting them to active plastic deformation. Despite the glassy regime, the bulk plastic deformation triggered the requisite molecular mobility of the polymer chains, causing interpenetration across the interfaces held in contact. Quantitative levels of adhesion and the morphologies of the fractured interfaces validated the sub-Tg, plasticity-induced, molecular mobilization causing bonding. No-bonding outcomes (i) during the compression of films in a near hydrostatic setting (which inhibited plastic flow) and (ii) between an 'elastic' and a 'plastic' film further established the explicit role of plastic deformation in this newly reported sub-Tg solid-state bonding

Emission Spectra of Isomeric Trifluorotoluidines

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The use of reflectance measurements in the determination of diffusion of reactive dyes into cellulosic fiber

Reactive dye fixation and color yield of a dyed cellulosic fiber significantly depend on the dye diffusion into the fiber polymer system. In case of pad-dyeing processes, dye diffusion exerts a more significant influence on dye fixation and hence color yield. This article proposes a new method for determining the extent of diffusion of reactive dyes into the fiber in pad dyeings using Kubelka-Munk equation. The K/S values are used as in an equation, %D (extent of dye diffusion) = 100 - [(K/S diffusion index)/ (K/S reference) × 100]. The article introduces and explains how to determine the new K/S variables used in this equation. The new method is simple, nondestructive, relatively faster, and applicable to industrial dyehouses, and was validated by a microscopic analysis of dyed fiber cross-section carried out in this work and to the dye manufacturer's recommendations for dyebath-ingredient concentrations

Mifepristone versus intracervical prostaglandin E2 gel for cervical ripening in primigravid patients at term

Background: The cervix has to play dual role in human reproduction. During pregnancy, it should remain firm and closed allowing the fetus to grow in utero until functional maturity is attained while during labour it should soften and dilate, allowing the fetus to pass through the birth canal. Objective of present study was to know and compare the effect of oral Mifepristone with intracervical dinoprostone gel for cervical priming prior to induction of labour at term in an unfavorable cervix of primigravida.Methods: This was prospective randomized comparative study. 100 primigravid patients were included, 50 were placed in each group A and B. Tablet Mifepristone 200mg orally was given in group A patients and intracervical dinoprostone gel induction was done in group B patients. Pre induction Bishop’s score was noted at beginning to compare improvement in Bishop’s score after induction. Mode of delivery and induction to delivery interval in both the groups were studied.Results: After induction with Mifepristone 76% women had successful cervical ripening as compared to 56% with dinoprostone. Rate of vaginal delivery was 70% with Mifepristone and 58% with dinoprostone. There was no significant difference in induction to delivery interval between the groups. Ten percent and 2% belonging to mifepristone and dinoprostone group respectively, required NICU admissions.Conclusions: Mifepristone is more effective than dinoprostone for preinduction cervical ripening as it has high success rate of achieving cervical ripening, however there is no significant difference in the vaginal delivery rate and other maternal and fetal outcome

Enhancing the Performance of the T-Peel Test for Thin and Flexible Adhered Laminates

Symmetrically bonded thin and flexible T-peel specimens, when tested on vertical travel machines, can be subject to significant gravitational loading; with the associated asymmetry and mixed-mode failure during peeling. This can cause erroneously high experimental peel forces to be recorded which leads to uncertainty in estimating interfacial fracture toughness and failure mode. To overcome these issues, a mechanical test fixture has been designed for use with vertical test machines, that supports the unpeeled portion of the test specimen and suppresses parasitic loads due to gravity from affecting the peel test. The mechanism, driven by the test machine cross-head, moves at one-half of the velocity of the cross-head such that the unpeeled portion always lies in the plane of the instantaneous center of motion. Several specimens such as bonded polymeric films, laminates, and commercial tapes were tested with and without the fixture, and the importance of the proposed T-peel procedure has been demonstrated

Quantum illumination using polarization-path entangled single photons for low reflectivity object detection in noisy background

Detecting object with low reflectivity embedded within a noisy background is a challenging task. Quantum correlations between pairs of quantum states of light, though are highly sensitive to background noise and losses, offer advantages over traditional illumination methods. Instead of using correlated photon pairs which are sensitive, we experimentally demonstrate the advantage of using heralded single-photons entangled in polarization and path degree of freedom for quantum illumination. In the study, the object of different reflectivity is placed along the path of the signal in a variable thermal background before taking the joint measurements and calculating the quantum correlations. We show the significant advantage of using non-interferometric measurements along the multiple paths for single photon to isolate the signal from the background noise and outperform in detecting and ranging the low reflectivity objects even when the signal-to-noise ratio is as low as 0.03. Decrease in visibility of polarization along the signal path also results in similar observations. This will have direct relevance to the development of single-photon based quantum LiDAR and quantum imaging.Comment: 8 pages and 6 figure

Second-order correlations and purity of unheralded single photons from spontaneous parametric down-conversion

Various quantum technology applications require high-purity single photons with high generation rate. Although different methods are employed to generate such photons, heralded single photons from spontaneous parametric down-conversion (SPDC) is the most commonly used approach. Photon generation rate from the heralded single-photon sources are limited by the efficiency of the detectors to record coincidence detection of the photon pairs which are lower than the single-photon counts recorded separately on each detector. In this paper we present a revised expression to calculate second-order temporal correlation function, $g^{(2)}$ for any fixed time window (bin) and report the experimental characterization of purity of unheralded and heralded single photons from the SPDC process. With an appropriate choice of time bin for a given pump power, without heralding we show that higher rate of single photons with $g^{(2)}(0) = 0$ can be generated with very high probability.Comment: 7 pages, 6 figure