Theories and analyses of functionally graded circular plates

This paper presents the governing equations and analytical solutions of the classical and shear deformation theories of functionally graded axisymmetric circular plates. The classical, first-order, and third-order shear deformation theories are presented, accounting for through-thickness variation of two-constituent functionally graded material, modified couple stress effect, and the von Kármán nonlinearity. Analytical solutions for bending of the linear theories, some of which are not readily available in the literature, are included to show the influence of the material variation, boundary conditions, and loads

Resonator-based detection in nanorods

In this paper the axial vibrational behaviour of nanorods with an attached point-mass is studied, using the modified strain energy theory. The natural frequencies of the nanorod with the concentrated mass are obtained for different boundary conditions. The effects of the concentrated mass intensity, mass location, as well as the value of scale parameters have been analysed. For the case of small intensity of the concentrated mass, the natural frequencies of the nanorod can be estimated using a first order perturbative solution. These approximate results are compared with those corresponding to the exact solution. For this case, from the properties of the eigenvalue perturbative theory, the identification of single point mass in uniform nanorods (mass intensity and position) is addressed. The results obtained encourage the use of axial vibrations of nanorods as a very precise sensing technique

Solar neutrino detection sensitivity in DARWIN via electron scattering

We detail the sensitivity of the proposed liquid xenon DARWIN observatory to solar neutrinos via elastic electron scattering. We find that DARWIN will have the potential to measure the fluxes of five solar neutrino components: pp, 7Be, 13N, 15O and pep. The precision of the13N, 15O and pep components is hindered by the doublebeta decay of 136Xe and, thus, would benefit from a depleted target. A high-statistics observation of pp neutrinos would allow us to infer the values of the electroweak mixing angle,sin2 θw, and the electron-type neutrino survival probability, Pee, in the electron recoil energy region from a few keV up to 200keV for the first time, with relative precision of 5% and 4%, respectively, with 10 live years of data and a 30 tonne fiducial volume. An observation of pp and 7Be neutrinos would constrain the neutrino-inferred solar luminosity down to 0.2%. A combination of all flux measurements would distinguish between the high- (GS98) and low-metallicity (AGS09) solar models with 2.1–2.5σ significance, independent of external measurements from other experiments or a measurement of8B neutrinos through coherent elastic neutrino-nucleus scattering in DARWIN. Finally, we demonstrate that with a depleted target DARWIN may be sensitive to the neutrino capture process of 131Xe

Improving the light collection efficiency of silicon photomultipliers through the use of metalenses

Metalenses are optical devices that implement nanostructures as phase shifters to focus incident light. Their compactness and simple fabrication make them a potential cost-effective solution for increasing light collection efficiency in particle detectors with limited photosensitive area coverage. Here we report on the characterization and performance of metalenses in increasing the light collection efficiency of silicon photomultipliers (SiPM) of various sizes using an LED of 630 nm, and find a six to seven-fold increase in signal for a 1.3×1.3 mm² SiPM when coupled with a 10-mm-diameter metalens manufactured using deep ultraviolet stepper lithography. Such improvements could be valuable for future generations of particle detectors, particularly those employed in rare-event searches such as dark matter and neutrinoless double beta decay

Numerical analysis for design of bioinspired ceramic modular armors for ballistic protections

[EN] The exigent requirements for personal protections in terms of energy absorption and ergonomics have led to increasing interest in bioinspired protections. This work focuses on the numerical analysis of ballistic behavior of different bioinspired geometries under impact loadings. Ceramic armors based on ganoid fish scales (the type exhibited by gars, bichirs and reedfishes), placoid fish scales (characterizing sharks and rays) and armadillo natural protection have been considered. Different impact conditions are studied, including perpendicular and oblique impacts to surface protection, different yaw angle, and multiple impacts. Main conclusion is related to the improved efficiency of modular armors against multiple shots exhibiting more localized damage and crack arrest properties. Moreover, its potential ergonomic is a promising characteristic justifying a deeper study.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work has been carried out within the framework of the research program Juan de la Cierva Incorporacion 2015, and research projects DPI2017-88166-R, and RTC-2015-3887-8 of FEDER program financed by the Ministerio de Economia, Industria y Competitividad of Spain. The support of the Generalitat Valenciana, Programme PROMETEO 2016/007 is also acknowledged.González Albuixech, VF.; Rodríguez-Millán, M.; Ito, T.; Loya, JA.; Miguélez, MH. (2019). Numerical analysis for design of bioinspired ceramic modular armors for ballistic protections. International Journal of Damage Mechanics. 28(6):815-837. https://doi.org/10.1177/1056789518795203S815837286Chen, I. H., Kiang, J. H., Correa, V., Lopez, M. I., Chen, P.-Y., McKittrick, J., & Meyers, M. A. (2011). Armadillo armor: Mechanical testing and micro-structural evaluation. Journal of the Mechanical Behavior of Biomedical Materials, 4(5), 713-722. doi:10.1016/j.jmbbm.2010.12.013Chintapalli, R. K., Mirkhalaf, M., Dastjerdi, A. K., & Barthelat, F. (2014). Fabrication, testing and modeling of a new flexible armor inspired from natural fish scales and osteoderms. Bioinspiration & Biomimetics, 9(3), 036005. doi:10.1088/1748-3182/9/3/036005Deka, L. J., Bartus, S. D., & Vaidya, U. K. (2009). Multi-site impact response of S2-glass/epoxy composite laminates. Composites Science and Technology, 69(6), 725-735. doi:10.1016/j.compscitech.2008.03.002Duro-Royo, J., Zolotovsky, K., Mogas-Soldevila, L., Varshney, S., Oxman, N., Boyce, M. C., & Ortiz, C. (2015). MetaMesh: A hierarchical computational model for design and fabrication of biomimetic armored surfaces. Computer-Aided Design, 60, 14-27. doi:10.1016/j.cad.2014.05.005Flores-Johnson, E. A., Shen, L., Guiamatsia, I., & Nguyen, G. D. (2014). Numerical investigation of the impact behaviour of bioinspired nacre-like aluminium composite plates. Composites Science and Technology, 96, 13-22. doi:10.1016/j.compscitech.2014.03.001Grujicic, M., Pandurangan, B., & Coutris, N. (2011). A Computational Investigation of the Multi-Hit Ballistic-Protection Performance of Laminated Transparent-armor Systems. Journal of Materials Engineering and Performance, 21(6), 837-848. doi:10.1007/s11665-011-0004-3Grunenfelder, L. K., Suksangpanya, N., Salinas, C., Milliron, G., Yaraghi, N., Herrera, S., … Kisailus, D. (2014). Bio-inspired impact-resistant composites. Acta Biomaterialia, 10(9), 3997-4008. doi:10.1016/j.actbio.2014.03.022Klasztorny, M., & Świerczewski, M. (2015). NUMERICAL MODELLING AND VALIDATION OF 12.7 MM FSP IMPACT INTO ALFC SHIELD – ARMOX 500T STEEL PLATE SYSTEM. Journal of KONES. Powertrain and Transport, 19(4), 291-299. doi:10.5604/12314005.1138463Liu, P., Zhu, D., Yao, Y., Wang, J., & Bui, T. Q. (2016). Numerical simulation of ballistic impact behavior of bio-inspired scale-like protection system. Materials & Design, 99, 201-210. doi:10.1016/j.matdes.2016.03.040Morka, A., & Nowak, J. (2015). NUMERICAL ANALYSES OF CERAMIC/METAL BALLISTIC PANELS SUBJECTED TO PROJECTILE IMPACT. Journal of KONES. Powertrain and Transport, 19(4), 465-472. doi:10.5604/12314005.1138618Pandya, K., Kumar, C. V. S., Nair, N., Patil, P., & Naik, N. (2014). Analytical and experimental studies on ballistic impact behavior of 2D woven fabric composites. International Journal of Damage Mechanics, 24(4), 471-511. doi:10.1177/1056789514531440Poniżnik, Z., Nowak, Z., & Basista, M. (2015). Numerical modeling of deformation and fracture of reinforcing fibers in ceramic–metal composites. International Journal of Damage Mechanics, 26(5), 711-734. doi:10.1177/1056789515611945Porter, M. M., Ravikumar, N., Barthelat, F., & Martini, R. (2017). 3D-printing and mechanics of bio-inspired articulated and multi-material structures. Journal of the Mechanical Behavior of Biomedical Materials, 73, 114-126. doi:10.1016/j.jmbbm.2016.12.016Reaugh, J. E., Holt, A. C., Welkins, M. L., Cunningham, B. J., Hord, B. L., & Kusubov, A. S. (1999). Impact studies of five ceramic materials and pyrex. International Journal of Impact Engineering, 23(1), 771-782. doi:10.1016/s0734-743x(99)00121-9Rostamiyan, Y., & Ferasat, A. (2016). High-speed impact and mechanical strength of ZrO2/polycarbonate nanocomposite. International Journal of Damage Mechanics, 26(7), 989-1002. doi:10.1177/1056789516644312Russell, B. P. (2014). Multi-hit ballistic damage characterisation of 304 stainless steel plates with finite elements. Materials & Design, 58, 252-264. doi:10.1016/j.matdes.2014.01.074Serjouei, A., Chi, R., Sridhar, I., & Tan, G. E. B. (2015). Empirical Ballistic Limit Velocity Model for Bi-Layer Ceramic–Metal Armor. International Journal of Protective Structures, 6(3), 509-527. doi:10.1260/2041-4196.6.3.509Shaktivesh, Nair, N., & Naik, N. (2014). Ballistic impact behavior of 2D plain weave fabric targets with multiple layers: Analytical formulation. International Journal of Damage Mechanics, 24(1), 116-150. doi:10.1177/1056789514524074Yang, W., Chen, I. H., Gludovatz, B., Zimmermann, E. A., Ritchie, R. O., & Meyers, M. A. (2012). Natural Flexible Dermal Armor. Advanced Materials, 25(1), 31-48. doi:10.1002/adma.20120271

Functional Determinants in Quantum Field Theory

Functional determinants of differential operators play a prominent role in theoretical and mathematical physics, and in particular in quantum field theory. They are, however, difficult to compute in non-trivial cases. For one dimensional problems, a classical result of Gel'fand and Yaglom dramatically simplifies the problem so that the functional determinant can be computed without computing the spectrum of eigenvalues. Here I report recent progress in extending this approach to higher dimensions (i.e., functional determinants of partial differential operators), with applications in quantum field theory.Comment: Plenary talk at QTS5 (Quantum Theory and Symmetries); 16 pp, 2 fig

Soft–bottom sipunculans from San Pedro del Pinatar (Western Mediterranean): influence of anthropogenic impacts and sediment characteristics on their distribution

We analysed the distribution of soft bottom sipunculans from San Pedro del Pinatar (Western Mediterranean). This study was carried out from December 2005 to June 2010, sampling with biannual periodicity (June and December). Physical and chemical parameters of the sediment were analysed (granulometry, organic matter content, pH, bottom salinity and shelter availability). Nine different species and subspecies were identified, belonging to five families. Aspidosiphon muelleri muelleri was the dominant species, accumulating 89.06% of the total abundance of sipunculans. Higher sipunculan abundances were correlated with stations of higher percentage of coarse sand, empty mollusc shells and empty tubes of the serpulid polychaete Ditrupa arietina, where some of the recorded species live. Sediment characteristics played the main role controlling the sipunculans distribution. Anthropogenic impacts could be indirectly affecting their distribution, changing the sediment characteristics. Key words: Sipuncula, Aspidosiphon muelleri, Mediterranean, Anthropogenic impact, Soft–bottom.Se analizó la distribución de los sipuncúlidos de fondos blandos de San Pedro del Pinatar (Mediterráneo occidental). Este estudio se llevó a cabo entre diciembre de 2005 y junio de 2010, muestreando con periodicidad semestral (junio y diciembre). Se analizaron parámetros físicos y químicos del sedimento (granulometría, contenido de materia orgánica, pH, salinidad de fondo y disponibilidad de refugio). Nueve especies y subespecies diferentes fueron identificadas, pertenecientes a cinco familias. Aspidosiphon muelleri muelleri fue la especie dominante, acumulando el 89,06% de la abundancia total de sipuncúlidos. Las mayores abundancias de sipuncúlidos se correlacionaron con las estaciones con mayores porcentajes de arena gruesa, conchas de moluscos vacías y tubos vacíos del poliqueto serpúlido Ditrupa arietina, donde viven algunas de las especies registradas. Las características del sedimento jugaron el papel principal en el control de la distribución de sipuncúlidos. Los impactos antropogénicos podrían estar afectando indirectamente su distribución, cambiando las características del sedimento. Palabras clave: Sipuncúlidos, Aspidosiphon muelleri, Mediterráneo, Impacto antropogénico, Fondos blandos.We analysed the distribution of soft bottom sipunculans from San Pedro del Pinatar (Western Mediterranean). This study was carried out from December 2005 to June 2010, sampling with biannual periodicity (June and December). Physical and chemical parameters of the sediment were analysed (granulometry, organic matter content, pH, bottom salinity and shelter availability). Nine different species and subspecies were identified, belonging to five families. Aspidosiphon muelleri muelleri was the dominant species, accumulating 89.06% of the total abundance of sipunculans. Higher sipunculan abundances were correlated with stations of higher percentage of coarse sand, empty mollusc shells and empty tubes of the serpulid polychaete Ditrupa arietina, where some of the recorded species live. Sediment characteristics played the main role controlling the sipunculans distribution. Anthropogenic impacts could be indirectly affecting their distribution, changing the sediment characteristics. Key words: Sipuncula, Aspidosiphon muelleri, Mediterranean, Anthropogenic impact, Soft–bottom

The ubiquitous ζ\zeta-function and some of its "usual" and "unusual" meromorphic properties

In this contribution we announce a complete classification and new exotic phenomena of the meromorphic structure of \z-functions associated to conic manifolds proved in \cite{KLP1}. In particular, we show that the meromorphic extensions of these \z-functions have, in general, countably many logarithmic branch cuts on the nonpositive real axis and unusual locations of poles with arbitrarily large multiplicity. Moreover, we give a precise algebraic-combinatorial formula to compute the coefficients of the leading order terms of the singularities.Comment: Paper presented at the 8th Workshop on Quantum Field Theory under the Influence of External Conditions (Leipzig, Germany, 16-21 September, 2007

Vacuum Expectation Value of the Spinor Massive field in the Cosmic String Space-Time

We found the contribution to the vacuum expectation value of the energy-momentum tensor of a massive Dirac field due to the conical geometry of the cosmic string space-time. The heat kernel and heat kernel expansion for the squared Dirac operator in this background are also considered and the first three coefficients were found in an explicity form.Comment: 9 pages, 1 figure (2 ref added) (enlarged version