Commentary: Roles,opportunities, and challenges—science museums engaging the public in emerging science and technology

Even a cursory reading of the public engagement in science (PES) literature over the past decade reveals that public engagement is becoming part of the “orthodoxy of 21st century science policy” (Stilgoe, Nanodialogues: experiments in public engagement with science, 2007, p 16), Moving forward, there appears to be strong consensus that (1) public engagement is an essential component for shaping sound science policies, research agendas, and governance structures; (2) more opportunities for accessible and successful PES need to be developed and implemented to have meaningful impact; and (3) a broader and more diverse range of publics need to be reached through PES activities. This article explores the role that U.S. science museums and centers could play in creating and delivering PES programming focusing on current science and technology developments and issues, with particular attention to nanoscience and nanotechnology. Also addressed will be some of the factors that support increased PES involvement by museums, some of the challenges museums need to overcome to sustain ongoing PES, and several recommendations to achieve broader PES impact through science museum participation.     

Hydroxyl radical imaging at kHz rates using a frequency-quadrupled Nd:YLF laser

Laser-induced fluorescence imaging of hydroxyl radicals has been an important tool in combustion research for more than twenty years. More recently, high frame rate imaging of hydroxyl radicals has been demonstrated using Nd:YAG-pumped dye laser systems. This work describes how a high repetition rate frequency-quadrupled Nd:YLF laser emitting at 263 nm can be used for laser-induced fluorescence imaging of hydroxyl radicals with less complexity. Hydroxyl radicals are excited in the A–X (2,0) band and redshifted fluorescence emission is detected with an image intensified CMOS camera at kHz frame rates. Furthermore, a strategy for high-speed temperature imaging is described.     

Simultaneous flow field and fuel concentration imaging at 4.8 kHz in an operating engine

High-speed particle image velocimetry (PIV) and planar laser induced fluorescence (PLIF) techniques are combined to acquire flow field and fuel concentration in a spray-guided spark-ignited direct-injection (SG-SIDI) engine under motored and fired operation. This is a crucial step to enable studies that seek correlations between marginal engine operation (misfires or partial burns) and local, instantaneous mixture and flow conditions. Correlated flow and fuel data are extracted from a 4 mm×4 mm sub-region directly downstream the spark plug to characterize the in-cylinder conditions next to the spark plug during the spray and ignition event. Values of equivalence ratio, velocity magnitude, shear strain rate, and vorticity all increase during the spray event and decrease an order of magnitude during the duration of the spark event.     

Squarks and gluinos at a TeV e + e − collider: testing the identity of Yukawa and gauge couplings in SUSY-QCD

Supersymmetry predicts the identity of Yukawa and gauge couplings in the QCD sector: . We examine whether the  Yukawa coupling can be determined, by methods complementary to LHC, by analyzing squark–gluino final states at a TeV e ⁺ e ⁻ collider.     

Laser-induced-forward-transfer: a rapid prototyping tool for fabrication of photonic devices

We propose a rapid prototyping method for the fabrication of optical waveguides based on the direct laser-printing method of ultrafast Laser-Induced Forward Transfer (LIFT) followed by further processing. The method was implemented for the fabrication of titanium in-diffused lithium niobate channel waveguides and X-couplers by LIFT-depositing titanium metal followed by diffusion. Propagation loss as low as 0.8 dB/cm was measured in preliminary experiments.     

Diffraction and correlations at the LHC: definitions and observables

We note that the definition of diffractive events is a matter of convention. We discuss two possible “definitions”: one based on unitarity and the other on Large Rapidity Gaps (LRG) or Pomeron exchange. LRG can also arise from fluctuations and we quantify this effect and some of the related uncertainties. We find care must be taken in extracting the Pomeron contribution from LRG events. We show that long-range correlations in multiplicities can arise from the same multi-Pomeron diagrams that are responsible for LRG events, and we explain how early LHC data can illuminate our understanding of ‘soft’ interactions.     

Production of microstructures in wide-band-gap and organic materials using pulsed laser ablation at 157 nm wavelength

New results on three-dimensional microstructuring of fused silica, sapphire, calcium fluoride, magnesium fluoride, and PTFE using pulsed laser ablation at 157 nm wavelength are presented. A largely automated high-precision fluorine laser micromachining station was used for the investigations.     

Energy band and electron-vibration coupling in organic thin films: photoelectron spectroscopy as a powerful tool for studying the charge transport

This article describes the origins of the width of the highest occupied molecular orbital (HOMO) state observed in the ultraviolet photoemission spectra (UPS) of thin organic semiconductor films. Although much research has been performed on the electrical properties of organic devices, a lot of crucial problems still remain. Among these problems, the charge mobility in organic semiconductor systems is one the most important subjects to be elucidated. In order to discuss the mobility, it is essential to understand both the intermolecular interaction and the electron-molecular vibration coupling. Experimental measurements of the energy band dispersion give information about the intermolecular interaction, and experimental detection of the HOMO hole-vibration coupling is indispensable to comprehend impacts of the electron-vibration coupling on the hole transport. Since most of the information is hidden behind the finite bandwidth of the HOMO, only careful UPS measurements can provide information on these important phenomena related to charge carrier dynamics. In this article, we summarize our recent challenges on UPS measurements of organic thin films, which give the band dispersion of the HOMO and the HOMO hole-vibration coupling, and discuss the origins of the UPS bandwidth that relates to the charge carrier dynamics.     

Optical characterization of photopolymers materials: theoretical and experimental examination of primary radical generation

Several studies of the time varying photon absorption effects, which occur during the photo-initiation process in photopolymer materials, have been presented. Three primary mechanisms have been identified: (i) the dye absorption, (ii) recovery, and (iii) bleaching. Based on an analysis of these mechanisms, the production of primary radicals can be physically described and modelled. In free radical photo-polymerization systems, the excited dye molecules induce the production of the primary radicals, R ^?, which is a key factor in determining how much monomer is polymerized. This, in turn, is closely related to the refractive index modulation formed during holographic recording. In this article, by modifying the composition of a polyvinylalcohol/acrylamide based photopolymer material, i.e. excluding any co-initiator, the photo-kinetic behaviour of the material is greatly simplified. In this way, the rate constant of intersystem crossing, k _st, in going from the excited singlet state dye to the excited triple state dye can be determined. k _st is then available to be applied in a full model of the photo-initiation process making it possible to accurately predict the time varying concentration of primary radicals generated during exposure.     

Nonlinear Effect and Atomic Entanglement in a Coupled-Cavity Array

By introducing the nonlinear effects that arise from Kerr medium, we theoretically study the nonlinear effect and the entanglement between two atoms in two coupled cavities. We give out the process of dynamic stability and solve the eigen problem of the system under high-intensive fields. The dynamics of the two coupled cavity with high-intensity fields inside is also studied numerically, the effects of atom-field coupling on the self-trapping as well as on the entanglement are also analyzed and discussed. In vacuum and high-intensity fields we calculate the concurrence of the two atoms in both theoretical and realistic situation, and discuss the nonlinear effect on the atomic entanglement. The result shows that the nonlinear interaction can play a controlling role in entangling two atoms.     

Proposal for the Simultaneous Measurement of the Neutron–Neutron and Neutron–Proton Quasi-Free Scattering Cross Section via the Neutron–Deuteron Breakup Reaction at E n = 19 MeV

In order to confirm or refute the present discrepancy between data and calculation for the neutron–neutron quasi-free scattering cross section in the neutron–deuteron breakup reaction, we describe a new experimental approach currently being pursued at TUNL.     

IR thermometry: a new tool for contactless in situ investigations of metal–insulator transition

In the present work, we focus on an original study of metal–insulator transition in LaNiO₃ (LNO) compound by IR camera mounted on a pulsed laser deposition chamber. IR thermometry is based on the measurement of the radiated energy that is a function of the surface temperature and the emissivity (ε) of a material. Thus, at a fixed high temperature in an oxygen equilibrium state and by fixing arbitrary an emissivity value, we can follow the evolution of the “measured temperature” linked to the change of the real emissivity value during a reduction/reoxygenation treatment. The variation of emissivity is correlated to the change in optical constants, e.g. to the conductivity measured simultaneously by an in situ spectroscopic ellipsometry. The combination of both techniques offers a convenient way to observe in situ and contactless changes from metallic to insulator behavior and vice versa.     

Dispersion and Collapse in Stochastic Velocity Fields on a Cylinder

The dynamics of fluid particles on cylindrical manifolds is investigated. The velocity field is obtained by generalizing the isotropic Kraichnan ensemble, and is therefore Gaussian and decorrelated in time. The degree of compressibility is such that when the radius of the cylinder tends to infinity the fluid particles separate in an explosive way. Nevertheless, when the radius is finite the transition probability of the two-particle separation converges to an invariant measure. This behavior is due to the large-scale compressibility generated by the compactification of one dimension of the space.     

Incoherent dark spatial solitons and guiding white light in photosensitive polymeric materials

The planar dark spatial soliton supported by the photo-induced isomerization and reorientation of azo-dye Disperse Red 13 was generated in bulk Disperse Red 13 doped poly (methyl methacrylate) using incoherent red light from a continuous-wave He–Ne laser. The guiding of white light by such incoherent dark solitons was investigated for the first time.     

Precise predictions for Higgs production in association with a W-boson pair at ILC

Higgs-boson production in association with a W-boson pair at e ⁺ e ⁻ linear colliders is one of the important processes in probing the coupling between the Higgs boson and vector gauge bosons and discovering the signature of new physics. We describe the impact of the complete electroweak (EW) radiative corrections of to this process in the standard model (SM) at the International Linear Collider (ILC), and investigate the dependence of the lowest-order (LO) and EW next-to-leading order (NLO) corrected cross sections on the colliding energy and the Higgs-boson mass. The LO and NLO EW corrected distributions of the invariant mass of the W-boson pair and the transverse momenta of the final W-boson and Higgs boson are presented. Our numerical results show that the relative EW radiative correction (δ _ew) varies from −19.4% to 0.2% when m _H=120 GeV and grows from 300 GeV to 1.2 TeV.     

The Transformation Properties at the Quantum Level in Field Theories for a Gauge-Invariant System with a Higher-Order Lagrangian

Based on the configuration-space generating functional of the Green functions for the gauge-invariant system in higher-order derivatives theories, the equations of the transformation properties at the quantum level have been derived. It follows that the sufficient conditions are found which implies that there exists the conservation laws and the expressions of the quantal conserved laws are also given. Applying the results to the non-Abelian Chern-Simons higher-order derivatives theories, the quantal BRST conserved charge and other conserved charges are found, the transformation properties of the conformal transformation at the quantum level is discussed, the quantal conserved angular momentum is derived, it is pointed out that fractional spin in this system may be also preserved in quantum theories. But the connection between the symmetries and conservation laws in classical theories are not always preserved in quantum theories.     

Temperature distribution in deep tissue phantom during laser irradiation at 1,064 nm measured by thermocouples and thermal imaging technique

Abstract  

Moxibustion generates heat stimulation which expands blood vessels and promotes blood circulation. Furthermore, moxibustion provokes the release of diffuse noxious inhibitory controls (DNIC) to treat and prevent diseases. However, inherent drawbacks, such as pain, burn scars, smoke and bad smells, limit its use. A novel noncontact-type laser therapy device having effect similar to that of commercial moxibustion is being developed using a 1,064-nm infrared (IR) diode-pumped solid state (DPSS) laser. The therapy device allows direct interaction of laser light with the skin rendering temperature distribution both on the skin surface and deep under the skin. We devised a sample holder containing a tissue phantom to measure the three-dimensional temperature distribution with thermocouples inserted deep inside the phantom. Agar gel of 2.5% concentration was used as the tissue phantom in our experiments. Our results revealed that the maximum temperature occurred far below the surface of the tissue phantom, which was heated by laser irradiation at 1,064 nm. This occurrence was also confirmed by a thermal imaging method. In contrast, temperature gradually decreased through the depth of the tissue phantom heated with commercial moxibustion. Simple analytical models were constructed to explain the underlying heat-transfer mechanisms involved in moxibustion and laser irradiation.     

Particle resonance in the Dirac equation in the presence of a delta interaction and a perturbative hyperbolic potential

We show that the energy spectrum of the one-dimensional Dirac equation, in the presence of an attractive vectorial delta potential, exhibits a resonant behavior when one includes an asymptotically spatially vanishing weak electric field associated with a hyperbolic tangent potential. We solve the Dirac equation in terms of Gauss hyper-geometric functions and show explicitly how the resonant behavior depends on the strength of the electric field evaluated at the support of the point interaction. We derive an approximate expression for the value of the resonances and compare the results calculated for the hyperbolic potential with those obtained for a linear perturbative potential. Finally, we characterize the resonances with the help of the phase shift and the Wigner delay time.     

Search for top quark FCNC couplings in Z′ models at the LHC and CLIC

The top quark is the heaviest particle to date discovered, with a mass close to the electroweak symmetry breaking scale. It is expected that the top quark would be sensitive to the new physics at the TeV scale. One of the most important aspects of the top quark physics can be the investigation of the possible anomalous couplings. Here, we study the top quark flavor changing neutral current (FCNC) couplings via the extra gauge boson Z′ at the Large Hadron Collider (LHC) and the Compact Linear Collider (CLIC) energies. We calculate the total cross sections for the signal and the corresponding Standard Model (SM) background processes. For an FCNC mixing parameter x=0.2 and the sequential Z′ mass of 1 TeV, we find the single top quark FCNC production cross sections 0.38(1.76) fb at the LHC with $\sqrt{s_{pp}}=7(14)$ TeV, respectively. For the resonance production of sequential Z′ boson and decays to single top quark at the Compact Linear Collider (CLIC) energies, including the initial state radiation and beamstrahlung effects, we find the cross section to be 27.96(0.91) fb at $\sqrt{s_{e^{+}e^{-}}}=1(3)$ TeV, respectively. We make the analysis to investigate the parameter space (mixing-mass) through various Z′ models. It is shown that the results benefit from the flavor tagging.