Fiber Optic Detection of Ammonia Gas

Bathochromic shifts accompanying the formation of several bivalent metallic complexes containing 5-(4’-dimethylaminophenylimino) quinolin-8-one (L1), and 7-chlore-5(4’-diethylamino-2-methylphenylimino) quinolin-8-one (L2) ligands in ethanol solutions were evaluated by VIS-NIR spectroscopy. The [L1-Cu-L1] sulphide complex was selected as a reagent for further tests on optical fibres. Samples of multimode siloxane-clad fused-silica fibre were sensitized by diffusing an ethanol/chloroform solution of the dye into the cladding polymer, and tested by VIS-NIR optical spectroscopy (12 cm long fibre sections), and optical time domain reflectometry (OTDR; 20 ns laser pulses, wavelength 850 nm, 120 m long fibre sensitized within the interval 104–110 m). A well-resolved absorption band of the reagent could be identified in the absorption spectra of the fibres. After exposure to dry ammonia/nitrogen gas with increasing ammonia concentration (0–4000 ppm), the short fibre samples showed subsequent decay of NIR optical absorption; saturation was observed for higher ammonia levels. The concentration resolution r ? 50 ppm and forward response time t90 ? 30 sec were obtained within the interval 0–1000 ppm. The OTDR courses showed an enhancement of the back-scattered light intensity coming from the sensitized region after diffusion of the initial reagent, and decay after exposure to concentrated ammonia/nitrogen gas (10000 ppm)

PES fabric modification with a corona discharge

Paper presents results of experiments with polyethylene terephtalate (PET) focused on the applicability of atmospheric corona discharge for polyester fabric (PES) modification, mainly on the relation between corona discharge input power and the fabric’s hydrophobicity and modification efficiency. Modification effect strongly grew according to the discharge input power, but the growth was limited by the corona discharge conversion into the spark discharge. Modification effect aging expressed in the feathering spot size time changes sharply diminished in time. Results of corona discharge modification were compared with those of the RF discharge modificationВ роботі подаються результати експериментів з поліетилен-терфталатом (РЕТ), метою яких було виявлення можливості вживання атмосферного коронного розряду для модифікації поліефірного матеріалів (PES), головним чином, залежності гідрофобності матеріалів та ефективності їх модифікації від споживаної потужності коронного розряду. Ефект модифікації помітно зростав з споживаною потужністю, проте цей зріст обмежувався переходом коронного розряду в іскровий. Результати модифікації коронним розрядом порівнюються з результатами, які були одержані з застосуванням ВЧ розряду.В работе представлены результаты экспериментов с полиэтилен-терфталатом (РЕТ), целью которых было выяснение возможности применения атмосферного коронного разряда для модификации полиэфирного материалов (PES), главным образом, зависимости гидрофобности материалов и эффективности их модификации от потребляемой мощности коронного разряда. Эффект модификации заметно возрастал с потребляемой мощностью, но это возрастание ограничивалось переходом коронного разряда в искровой разряд. Результаты модификации коронным разрядом сравниваются с результатами, полученными при использовании ВЧ разряда

Discrete breathers in nonlinear lattices: Experimental detection in a Josephson array

We present an experimental study of discrete breathers in an underdamped Josephson-junction array. Breathers exist under a range of dc current biases and temperatures, and are detected by measuring dc voltages. We find the maximum allowable bias current for the breather is proportional to the array depinning current while the minimum current seems to be related to a junction retrapping mechanism. We have observed that this latter instability leads to the formation of multi-site breather states in the array. We have also studied the domain of existence of the breather at different values of the array parameters by varying the temperature.Comment: 5 pages, 5 figures, submitted to Physical Revie

Consistency tests of AMPCALCULATOR and chiral amplitudes in SU(3) Chiral Perturbation Theory: A tutorial based approach

Ampcalculator is a Mathematica based program that was made publicly available some time ago by Unterdorfer and Ecker. It enables the user to compute several processes at one-loop (upto $O(p^4)$) in SU(3) chiral perturbation theory. They include computing matrix elements and form factors for strong and non-leptonic weak processes with at most six external states. It was used to compute some novel processes and was tested against well-known results by the original authors. Here we present the results of several thorough checks of the package. Exhaustive checks performed by the original authors are not publicly available, and hence the present effort. Some new results are obtained from the software especially in the kaon odd-intrinsic parity non-leptonic decay sector involving the coupling $G_{27}$. Another illustrative set of amplitudes at tree level we provide is in the context of $\tau$-decays with several mesons including quark mass effects, of use to the BELLE experiment. All eight meson-meson scattering amplitudes have been checked. Kaon-Compton amplitude has been checked and a minor error in published results has been pointed out. This exercise is a tutorial based one, wherein several input and output notebooks are also being made available as ancillary files on the arXiv. Some of the additional notebooks we provide contain explicit expressions that we have used for comparison with established results. The purpose is to encourage users to apply the software to suit their specific needs. An automatic amplitude generator of this type can provide error-free outputs that could be used as inputs for further simplification, and used in varied scenarios such as applications of chiral perturbation theory at finite temperature, density and volume. This can also be used by students as a learning aid in low-energy hadron dynamics.Comment: 25 pages, plain latex, corresponds to version to appear in EPJA, additional ancillary files adde

tau-->eta(eta')2pi nu, 3pi nu and WZW anomaly

The effects of the anomalous contact terms are taken into account in tau to eta(eta')2pi nu decay. tau to 3pi nu is computed. Theoretical result agrees with data. It is the first time the anomalous vertex eta aa is tested. An a_{1} resonance is predicted in the final state. The decay rate of tau to eta'3pi nu is predicted.Comment: 15 pages, one latex file for the paper and one p-script file for the figur

Transcription Inhibition by DRB Potentiates Recombinational Repair of UV Lesions in Mammalian Cells

Homologous recombination (HR) is intricately associated with replication, transcription and DNA repair in all organisms studied. However, the interplay between all these processes occurring simultaneously on the same DNA molecule is still poorly understood. Here, we study the interplay between transcription and HR during ultraviolet light (UV)-induced DNA damage in mammalian cells. Our results show that inhibition of transcription with 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) increases the number of UV-induced DNA lesions (γH2AX, 53BP1 foci formation), which correlates with a decrease in the survival of wild type or nucleotide excision repair defective cells. Furthermore, we observe an increase in RAD51 foci formation, suggesting HR is triggered in response to an increase in UV-induced DSBs, while inhibiting transcription. Unexpectedly, we observe that DRB fails to sensitise HR defective cells to UV treatment. Thus, increased RAD51 foci formation correlates with increased cell death, suggesting the existence of a futile HR repair of UV-induced DSBs which is linked to transcription inhibition

Probing Lepton-number/flavour-violation in Semileptonic Tau Decays into Two Mesons

The evaluation, systematic analysis and numerical study of the semileptonic $\tau$-lepton decays with two mesons in the final state has been made in the frame of the standard model extended by right handed neutrinos. In the analysis, heavy-neutrino nondecoupling effects, finite quark masses, quark and meson mixings, finite widths of vector mesons, chiral symmetry breakings in vector-meson--pseudoscalar-meson vertices and effective Higgs-boson--pseudoscalar-meson couplings have been included. Numerical estimates reveal that the decays $\tau^-\to e^-\pi^-\pi^+$, $\tau^-\to e^-K^-K^+$ and $\tau^-\to e^-K^0\bar{K}^0$ have branching ratios of the order of $10^{-6}$, close to present-day experimental sensitivities.Comment: 33 pages, LaTeX, 6 Postscript figures. To appearin Phys. Rev.