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Search for an exotic decay of the Higgs boson to a pair of light pseudoscalars in the final state with two muons and two b quarks in pp collisions at 13 TeV
No full textA search for exotic decays of the Higgs boson to a pair of light pseudoscalar particles a(1) is performed under the hypothesis that one of the pseudoscalars decays to a pair of opposite sign muons and the other decays to b (b) over bar. Such signatures are predicted in a number of extensions of the standard model (SM), including next-to-minimal supersymmetry and two-Higgs-doublet models with an additional scalar singlet. The results are based on a data set of proton-proton collisions corresponding to an integrated luminosity of 35.9 fb(-1), accumulated with the CMS experiment at the CERN LHC in 2016 at a centre-of-mass energy of 13 TeV. No statistically significant excess is observed with respect to the SM backgrounds in the search region for pseudoscalar masses from 20 GeV to half of the Higgs boson mass. Upper limits at 95% confidence level are set on the product of the production cross section and branching fraction, sigma B-h(h -> a(1)a(1) -> mu (+)mu(-) b (b) over bar), ranging from 5 to 33 fb, depending on the pseudoscalar mass. Corresponding limits on the branching fraction, assuming the SM prediction for sigma(h), are (1-7) x 10(-4)
Spatially resolved solid-phase temperature characterization in a sillimanite tube furnace using a broadband two-color ratio pyrometry
No full textTube furnaces are heating devices used for the synthesis of inorganic and organic compounds. It is essential to predict the spatially resolved temperature of solid substances placed inside tube furnaces in contact with its walls for a fixed steady temperature of the furnace walls. This enables efficient study of transport phenomena and control of the fabrication process in the furnace. In this work, the two-color ratio pyrometry (TCRP) using a digital single lens reflex camera has been used for the temperature characterization of a stainless steel metal sheet placed at the center of a 1000 mm long tube furnace. Temperature was measured for furnace walls set between 1000 K and 1426 K. The TCRP technique accounted for intensity from the heated target over the broadband visible region. The camera was calibrated and tested for signal linearity in its color channels for a fixed source illumination. The technique yields a mean sheet temperature of 979.5 K +/- similar to 24% (attributed to camera noise and uncertainties in gray level intensity, calibration lamp output, and monochromator and photodetector efficiency) and 1391 K +/- 6.7% for a furnace wall temperature of 1000 K and 1426 K, respectively. Experiments showed that the effect of distance between the target and the camera on temperature measurement was negligible. Emission spectroscopy in the vis-near-infrared region (650-1100 nm) was also performed to predict sheet temperature. It yields results within 4.5% of TCRP at low furnace temperature but deviates by about 8.6% for temperatures above 1150 K, most likely due to experimental errors in spectroscopy. Analytical heat balance on the sheet, IR imaging, and numerical simulations yield temperatures within 5% of TCRP. This work shows that the TCRP technique can be used for spatially resolved temperature measurements of metals in tube furnaces and can readily be extended to ceramics or other class of solid materials whose emissivity can be shown to be invariant with wavelength in the visible region
Role of spin mixing conductance in determining thermal spin pumping near the ferromagnetic phase transition in EuO1-x and La2NiMnO6
No full textWe present a comprehensive study of the temperature (T) dependence of the longitudinal spin Seebeck effect (LSSE) in Pt/EuO1-x and Pt/La2NiMnO6 (LNMO) hybrid structures across their Curie temperatures (T-c). Both systems host ferromagnetic interaction below T-c, and hence present optimal conditions for testing magnon spin current based theories against ferrimagnetic yttrium iron garnet. Notably, we observe an anomalous Nernst effect generated voltage in bare EuO1-x, however, we find LSSE predominates the thermal signals in the bilayers with Pt. The T dependence of the LSSE in small T range near T-c could be fitted to a power law of the form (T-c- T)(p). The derived critical exponent P was verified for different methods of LSSE representation and sample crystallinity. The results are explained based on the magnon-driven thermal spin pumping mechanism that relates the T dependence of LSSE to the spin mixing conductance (G(mix)) at the heavy metal/ferromagnet interface, which in turn is known to vary inaccordance with the square of the spontaneous magnetization (M-s). Additionally, the T dependence of the real part of G(mix) derived from spin Hall magnetoresistance measurements at different temperatures for the Pt/LNMO structure further establishes the interdependence
A numerical study of the indentation mechanics of shape memory alloys in different temperature regimes
No full textInstrumented indentation is a versatile technique to quantify not only the mechanical properties but also the phase transformation and recovery characteristics of shape memory alloys (SMAs). The objective of this work is to investigate the effect of temperature on the mechanics of spherical indentation of SMAs as manifested through stress induced martensite transformation (SIMT) and plastic yielding. To this end, finite element simulations of spherical indentation response of Ni-Ti based SMAs are carried out using a constitutive model that incorporates the combined effects of superelasticity and plasticity. A range of temperatures from well below to above the austenite finish temperature A(f) is considered. It is found that while SIMT is the governing deformation mode during indentation at temperatures below A(f), plastic yielding becomes significant at temperatures close to and above A(f). The load and mean contact pressure increase with temperature above A(f) at a given indentation depth. Also, the remnant depth ratio for a given load is lowest close to A(f). SIMT and plastic deformation influence the stress distribution differently depending on the temperature
Homo and hetero-bridged dinuclear copper(II) complex: Synthesis, X-ray structure and catalytic N-arylation
No full textTwo new dinuclear Cu(II) Schiff base compounds were synthesized, structurally characterized and their catalytic efficacy in N-arylation reaction was studied. Reaction of CuCl2 with two different polydentate Schiff base ligands viz. H(2)L1 (H(2)L1 = 1-(N-ortho-hydroxyacetophenimine)-ethane-2-ol) and H2L2 (H2L2 = 2-methoxy-6-(2-hydroxyethylimino)methyl]phenol) has afforded two new very different in structure complexes Cu-2(HL1)(2)(mu-Cl)(2)]center dot(H2O)(3) (1) and Cu2L2(HL2)(mu-Cl)Cl](2)center dot(H2O) (2). Complexes 1 and 2 were characterized by single crystal X-ray diffraction, FT-IR, elemental analysis, UV/Vis spectroscopic and TG/DTA studies. Complex 1 featured a simple dichloro-bridged dinuclear moiety, whereas 2 a hetero-bridged (chloro and phenolic oxygen) dinuclear compound. Catalytic efficacy towards N-arylation reactions between aryl iodide with aryl amine catalyzed by complexes 1 and 2 under homogeneous condition had been studied. Both the catalysts exhibited excellent catalytic efficacy in DMSO medium
MAXIMAL CLOSED SUBROOT SYSTEMS OF REAL AFFINE ROOT SYSTEMS
No full textWe completely classify and give explicit descriptions of all maximal closed subroot systems of real affine root systems. As an application, we describe a procedure to get the classification of all regular subalgebras of affine Kac-Moody algebras in terms of their root systems
Force sensing technologies for catheter ablation procedures
No full textCardiac Arrhythmia, a condition of abnormal activation and conduction of electrical impulses in the heart is observed in a large proportion of the world population. Radio frequency (RF) ablation catheters have revolutionized the treatment of cardiac arrhythmias. Over the years, researchers have been extensively working towards developing a more promising catheter technology that ensures definitive treatment. Since RF energy is based on the principle of resistive heating, to optimize effective lesion formation, a catheter to adequately sense tissue contact force becomes vital. The review focuses on state-of-the-art advancement in force sensors, design specification and their need for interfacing with cardiac catheters. Minimally invasive medical procedures for cardiac ablation followed by various controlling methods used for providing quality lesion have been overviewed. Several design prototypes and variants of force sensors that can potentially be integrated with ablation catheters are reviewed with their sensing principles and implementation
Beadex, a homologue of the vertebrate LIM domain only protein, is a novel regulator of crystal cell development in Drosophila melanogaster
No full textHaematopoiesis is a complex process in which the regulatory mechanisms of several implicated transcription factors remain uncertain. Drosophila melanogaster is an excellent model to resolve the unanswered questions about the blood cell development. This study describes the role of Beadex, a Drosophila homologue of LIM domain only 2 (LMO2), in haematopoiesis. Mutants of Beadex were analysed for blood cell abnormalities. Crystal cells, a subset of haemocytes, were significantly more in Beadex hypermorphic flies. Similarly, Beadex misexpression in prohemocytes altered the crystal cell numbers. Stage-specific misexpression analyses demonstrated that Beadex functions after the prohemocytes enter the crystal cell lineage. We also discovered that Pannier-U-shaped complex is a negative regulator of the crystal cell differentiation and is possibly negatively regulated by Beadex through its interaction with Pannier. We, therefore, suggest the mechanism of two novel regulators of crystal cell specification-Beadex and Pannier-during Drosophila haematopoiesis
An experimental study on performance of jute-polyester composite tubes under axial and transverse impact loading
No full textThe efficacy of woven jute-polyester (JP) composite tubes as structural energy-absorbing countermeasures has been explored in the current study. In this connection, the behaviors of 3-ply and 4-ply JP composite tubes of square and double-hat shaped sections subjected to axial quasi-static and impact loads are considered, and compared with 4-ply glass-polyester (GP) tubes of similar geometric configurations. Initially, basic mechanical characterization of JP laminates is carried out using a Universal Testing Machine, which is followed up with axial quasi-static and drop-weight impact testing of JP tubes, along with similar tests carried out on GP tubes. A thorough comparison is made between the performances including failure patterns of JP and GP components under axial loading using metrics such as peak load, mean crush load, absorbed energy, and specific energy absorption (SEA). As many structural applications involve dynamic bending loads, a comparative study is carried out between double-hat JP and GP components subjected to transverse impact loading. Based on the competitive values of mean load and SEA yielded by jute-composite tubes in the present study for axial impact loading, and high mean load and moderate energy absorption till failure recorded by similar components under three-point impact bending, it can be concluded that JP tubes can be capable of supporting impact loads under both axial and bending modes
Solenodon genome reveals convergent evolution of venom in eulipotyphlan mammals
No full textVenom systems are key adaptations that have evolved throughout the tree of life and typically facilitate predation or defense. Despite venoms being model systems for studying a variety of evolutionary and physiological processes, many taxonomic groups remain understudied, including venomous mammals. Within the order Eulipotyphla, multiple shrew species and solenodons have oral venom systems. Despite morphological variation of their delivery systems, it remains unclear whether venom represents the ancestral state in this group or is the result of multiple independent origins. We investigated the origin and evolution of venom in eulipotyphlans by characterizing the venom system of the endangered Hispaniolan solenodon (Solenodon paradoxus). We constructed a genome to underpin proteomic identifications of solenodon venom toxins, before undertaking evolutionary analyses of those constituents, and functional assessments of the secreted venom. Our findings show that solenodon venom consists of multiple paralogous kallikrein 1 (KLK1) serine proteases, which cause hypotensive effects in vivo, and seem likely to have evolved to facilitate vertebrate prey capture. Comparative analyses provide convincing evidence that the oral venom systems of solenodons and shrews have evolved convergently, with the 4 independent origins of venom in eulipotyphlans outnumbering all other venom origins in mammals. We find that KLK1s have been independently coopted into the venom of shrews and solenodons following their divergence during the late Cretaceous, suggesting that evolutionary constraints may be acting on these genes. Consequently, our findings represent a striking example of convergent molecular evolution and demonstrate that distinct structural backgrounds can yield equivalent functions