409 research outputs found

    Polynomial Realization of sâ„“q(2)s\ell_q(2) and Fusion Rules at Exceptional Values of qq

    Full text link
    Representations of the sâ„“q(2)s\ell_q(2) algebra are constructed in the space of polynomials of real (complex) variable for qN=1q^N=1. The spin addition rule based on eigenvalues of Casimir operator is illustrated on few simplest cases and conjecture for general case is formulated

    Towards the noise reduction of piezoelectrical-driven synthetic jet actuators

    Get PDF
    This paper details an experimental investigation aimed at reducing the noise output of piezoelectrical-driven synthetic jet actuators without compromising peak jet velocity. Specifically, the study considers double-chamber ('back-to-back') actuators for anti-phase noise suppression and corrugated-lobed orifices as a method to enhance turbulent mixing of the jets to suppress jet noise. The study involved the design, manufacture and bench test of interchangeable actuator hardware. Hot-wire anemometry and microphone recordings were employed to acquire velocity and noise measurements respectively for each chamber configuration and orifice plate across a range of excitation frequencies and for a fixed input voltage. The data analysis indicated a 32% noise reduction (20 dBA) from operating a singlechamber, circular orifice SJA to a double-chamber, corrugated-lobed orifice SJA at the Helmholtz resonant frequency. Results also showed there was a small reduction in peak jet velocity of 7% (~3 m/s) between these two cases based on orifices of the same discharge area. Finally, the electrical-to-fluidic power conversion efficiency of the double-chamber actuator was found to be 15% across all orifice designs at the resonant frequency; approximately double the efficiency of a single-chamber actuator. This work has thus demonstrated feasible gains in noise reduction and power efficiency through synthetic jet actuator design

    Higher Grading Conformal Affine Toda Teory and (Generalized) Sine-Gordon/Massive Thirring Duality

    Full text link
    Some properties of the higher grading integrable generalizations of the conformal affine Toda systems are studied. The fields associated to the non-zero grade generators are Dirac spinors. The effective action is written in terms of the Wess-Zumino-Novikov-Witten (WZNW) action associated to an affine Lie algebra, and an off-critical theory is obtained as the result of the spontaneous breakdown of the conformal symmetry. Moreover, the off-critical theory presents a remarkable equivalence between the Noether and topological currents of the model. Related to the off-critical model we define a real and local Lagrangian provided some reality conditions are imposed on the fields of the model. This real action model is expected to describe the soliton sector of the original model, and turns out to be the master action from which we uncover the weak-strong phases described by (generalized) massive Thirring and sine-Gordon type models, respectively. The case of any (untwisted) affine Lie algebra furnished with the principal gradation is studied in some detail. The example of sl^(n)(n=2,3)\hat{sl}(n) (n=2,3) is presented explicitly.Comment: 28 pages, JHEP styl

    Gene-based Interventions for Cancer Immunotherapy

    Get PDF
    Immunotherapy of cancer has deservedly gained much attention in the past few years and is likely to continue to advance and become a fundamental cancer treatment. While vaccines, chimeric antigen receptor (CAR) T cells and checkpoint blockade have received the lion’s share of the attention, an important direct role for gene transfer as an immunotherapy is emerging. For example, oncolytic viruses induce immunogenic cell death, thus liberating both antigens and the signals that are necessary for the activation of antigen-presenting cells, ensuring stimulation of an adaptive response. In another example, transfer of prodrug converting enzymes, such as the herpes simplex virus-thymidine kinase (HSV-tk) gene or the cytosine deaminase gene, has been shown to promote an immune response, thus functioning as immunotherapies. Alternatively, our own work involves the use of nonreplicating viral vectors for the simultaneous delivery of gene combinations that promote both cell death and an immune response. In fact, our gene transfer approach has been applied as a vaccine, immunotherapy or in situ gene therapy, resulting in immunogenic cell death and the induction of a protective immune response. Here, we highlight the development of these approaches both in terms of technical advances and clinical experience

    Soliton Spectrum of Integrable Models with Local Symmetries

    Full text link
    The soliton spectrum (massive and massless) of a family of integrable models with local U(1) and U(1)\otimes U(1) symmetries is studied. These models represent relevant integrable deformations of SL(2,R) \otimes U(1)^{n-1} - WZW and SL(2,R) \otimes SL(2,R)\otimes U(1)^{n-2} - WZW models. Their massless solitons appears as specific topological solutions of the U(1) (or U(1)\otimes U(1)) - CFTs. The nonconformal analog of the GKO-coset formula is derived and used in the construction of the composite massive solitons of the ungauged integrable models.Comment: 44 pages, Latex, 1 eps fig, few misprints corrected. to appear in JHE

    Dislocation-induced spin tunneling in Mn-12 acetate

    Full text link
    Comprehensive theory of quantum spin relaxation in Mn-12 acetate crystals is developed, that takes into account imperfections of the crystal structure and is based upon the generalization of the Landau-Zener effect for incoherent tunneling from excited energy levels. It is shown that linear dislocations at plausible concentrations provide the transverse anisotropy which is the main source of tunneling in Mn-12. Local rotations of the easy axis due to dislocations result in a transverse magnetic field generated by the field applied along the c-axis of the crystal, which explains the presence of odd tunneling resonances. Long-range deformations due to dislocations produce a broad distribution of tunnel splittings. The theory predicts that at subkelvin temperatures the relaxation curves for different tunneling resonances can be scaled onto a single master curve. The magnetic relaxation in the thermally activated regime follows the stretched-exponential law with the exponent depending on the field, temperature, and concentration of defects.Comment: 17 pages, 14 figures, 1 table, submitted to PR
    • …
    corecore