Threshold feedback control for a collective flashing ratchet: threshold dependence

We study the threshold control protocol for a collective flashing ratchet. In particular, we analyze the dependence of the current on the values of the thresholds. We have found analytical expressions for the small threshold dependence both for the few and for the many particle case. For few particles the current is a decreasing function of the thresholds, thus, the maximum current is reached for zero thresholds. In contrast, for many particles the optimal thresholds have a nonzero finite value. We have numerically checked the relation that allows to obtain the optimal thresholds for an infinite number of particles from the optimal period of the periodic protocol. These optimal thresholds for an infinite number of particles give good results for many particles. In addition, they also give good results for few particles due to the smooth dependence of the current up to these threshold values.Comment: LaTeX, 10 pages, 7 figures, improved version to appear in Phys. Rev.

Gender roles and intimate partner violence among female university students in Spain: A cross-sectional study

Background Traditional gender roles (GRs) have a considerable influence on relationships among couples. These can lead to negative health effects in women; however, their impact on intimate partner violence (IPV) has been less explored, especially among younger women. Objective To explore the association between traditional GRs and several indicators of IPV on a sample of Spanish female university students involved in heterosexual dating relationships. Methods A cross-sectional study involving female university students (n = 1, 005) pursuing ten degrees (four Health Science degrees and six Social Sciences degrees). Data were collected using two validated scales: 1) the Questionnaire on the Gender Determinants of Contraception (COGANT), used to examine four traditional GRs (submissive, blind, and passive attitudes of female students, and male dominance), and 2) the Dating Violence Questionnaire-R (DVQ-R) scale, used to measure five types of IPV-behaviors (coercion, detachment, humiliation, sexual violence, and physical violence), perceived fear, entrapment, and abuse. Logistic and linear regressions were conducted to study the association between GR and a series of IPV indicators in dating relationships. Results Traditional GRs were highly prevalent (57.0% submissive, 52.0% blind attitude, 75.7% passive, and 31.7% identified their boyfriend as being dominant). Up to 66.3% experienced some type of violent behavior. All GRs were significantly associated with IPV indicators. A submissive attitude in female students was the GR that was most strongly associated to total IPV-behavior (adjusted odd ratio [OR] = 3.18; 95% confidence interval [CI]: 2.29-4.42), followed by male dominance (OR = 2.79: 95% CI:1.71: 4.54). Both GRs were also highly associated with perceived fear, entrapment, and abuse. Conclusions A high presence of traditional GRs was found in the relationships held by female university students, which was significantly associated with IPV indicators. Universities must adopt policies for gender equality and raise awareness on dating violence. Copyright: © 2021 Llano-Suárez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Analysis of the Machinability of Carbon Fiber Composite Materials in Function of Tool Wear and Cutting Parameters Using the Artificial Neural Network Approach

[EN] Local delamination is the most undesirable damage associated with drilling carbon fiber reinforced composite materials (CFRPs). This defect reduces the structural integrity of the material, which affects the residual strength of the assembled components. A positive correlation between delamination extension and thrust force during the drilling process is reported in literature. The abrasive effect of the carbon fibers modifies the geometry of the fresh tool, which increases the thrust force and, in consequence, the induced damage in the workpiece. Using a control system based on an artificial neural network (ANN), an analysis of the influence of the tool wear in the thrust force during the drilling of CFRP laminate to reduce the damage is developed. The spindle speed, feed rate, and drill point angle are also included as input parameters of the study. The training and testing of the ANN model are carried out with experimental drilling tests using uncoated carbide helicoidal tools. The data were trained using error-back propagation-training algorithm (EBPTA). The use of the neural network rapidly provides results of the thrust force evolution in function of the tool wear and cutting parameters. The obtained results can be used by the industry as a guide to control the impact of the wear of the tool in the quality of the finished workpiece.The Ministry of Economy and Competitiveness of Spain, projects DPI2017-89197-C2-1-R and DPI2017-89197-C2-2-R] and the Ministry of Science, Innovation and Universities, grant number [FJCI-2017-34910], funded this research.Feito-Sánchez, N.; Muñoz-Sánchez, A.; Diaz-Alvarez, A.; Loya, J. (2019). Analysis of the Machinability of Carbon Fiber Composite Materials in Function of Tool Wear and Cutting Parameters Using the Artificial Neural Network Approach. Materials. 12(17):1-13. https://doi.org/10.3390/ma12172747S1131217Huang, X. (2009). Fabrication and Properties of Carbon Fibers. Materials, 2(4), 2369-2403. doi:10.3390/ma2042369Yang, Y., Jiang, Y., Liang, H., Yin, X., & Huang, Y. (2019). Study on Tensile Properties of CFRP Plates under Elevated Temperature Exposure. Materials, 12(12), 1995. doi:10.3390/ma12121995Liu, D., Tang, Y., & Cong, W. L. (2012). A review of mechanical drilling for composite laminates. Composite Structures, 94(4), 1265-1279. doi:10.1016/j.compstruct.2011.11.024Hocheng, H., & Tsao, C. . (2003). Comprehensive analysis of delamination in drilling of composite materials with various drill bits. Journal of Materials Processing Technology, 140(1-3), 335-339. doi:10.1016/s0924-0136(03)00749-0Hocheng, H., & Tsao, C. C. (2006). Effects of special drill bits on drilling-induced delamination of composite materials. International Journal of Machine Tools and Manufacture, 46(12-13), 1403-1416. doi:10.1016/j.ijmachtools.2005.10.004Hocheng, H., & Tsao, C. C. (2005). The path towards delamination-free drilling of composite materials. Journal of Materials Processing Technology, 167(2-3), 251-264. doi:10.1016/j.jmatprotec.2005.06.039Davim, J. ., & Reis, P. (2003). Study of delamination in drilling carbon fiber reinforced plastics (CFRP) using design experiments. Composite Structures, 59(4), 481-487. doi:10.1016/s0263-8223(02)00257-xSardiñas, R. Q., Reis, P., & Davim, J. P. (2006). Multi-objective optimization of cutting parameters for drilling laminate composite materials by using genetic algorithms. Composites Science and Technology, 66(15), 3083-3088. doi:10.1016/j.compscitech.2006.05.003Fernandes, M., & Cook, C. (2006). Drilling of carbon composites using a one shot drill bit. Part I: Five stage representation of drilling and factors affecting maximum force and torque. International Journal of Machine Tools and Manufacture, 46(1), 70-75. doi:10.1016/j.ijmachtools.2005.03.015Fernandes, M., & Cook, C. (2006). Drilling of carbon composites using a one shot drill bit. Part II: empirical modeling of maximum thrust force. International Journal of Machine Tools and Manufacture, 46(1), 76-79. doi:10.1016/j.ijmachtools.2005.03.016Feito, N., Diaz-Álvarez, A., Cantero, J. L., Rodríguez-Millán, M., & Miguélez, H. (2015). Experimental analysis of special tool geometries when drilling woven and multidirectional CFRPs. Journal of Reinforced Plastics and Composites, 35(1), 33-55. doi:10.1177/0731684415612931Feito, N., Díaz-Álvarez, J., Díaz-Álvarez, A., Cantero, J., & Miguélez, M. (2014). Experimental Analysis of the Influence of Drill Point Angle and Wear on the Drilling of Woven CFRPs. Materials, 7(6), 4258-4271. doi:10.3390/ma7064258Iliescu, D., Gehin, D., Gutierrez, M. E., & Girot, F. (2010). Modeling and tool wear in drilling of CFRP. International Journal of Machine Tools and Manufacture, 50(2), 204-213. doi:10.1016/j.ijmachtools.2009.10.004Abrão, A. M., Rubio, J. C. C., Faria, P. E., & Davim, J. P. (2008). The effect of cutting tool geometry on thrust force and delamination when drilling glass fibre reinforced plastic composite. Materials & Design, 29(2), 508-513. doi:10.1016/j.matdes.2007.01.016Rawat, S., & Attia, H. (2009). Wear mechanisms and tool life management of WC–Co drills during dry high speed drilling of woven carbon fibre composites. Wear, 267(5-8), 1022-1030. doi:10.1016/j.wear.2009.01.031Fernández-Pérez, J., Cantero, J. L., Díaz-Álvarez, J., & Miguélez, M. H. (2017). Influence of cutting parameters on tool wear and hole quality in composite aerospace components drilling. Composite Structures, 178, 157-161. doi:10.1016/j.compstruct.2017.06.043Tsao, C. C., & Hocheng, H. (2007). Effect of tool wear on delamination in drilling composite materials. International Journal of Mechanical Sciences, 49(8), 983-988. doi:10.1016/j.ijmecsci.2007.01.001Chen, W.-C. (1997). Some experimental investigations in the drilling of carbon fiber-reinforced plastic (CFRP) composite laminates. International Journal of Machine Tools and Manufacture, 37(8), 1097-1108. doi:10.1016/s0890-6955(96)00095-8Murphy, C., Byrne, G., & Gilchrist, M. D. (2002). The performance of coated tungsten carbide drills when machining carbon fibre-reinforced epoxy composite materials. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 216(2), 143-152. doi:10.1243/0954405021519735Fernández-Pérez, J., Cantero, J., Díaz-Álvarez, J., & Miguélez, M. (2019). Hybrid Composite-Metal Stack Drilling with Different Minimum Quantity Lubrication Levels. Materials, 12(3), 448. doi:10.3390/ma12030448Tsao, C. ., & Hocheng, H. (2004). Taguchi analysis of delamination associated with various drill bits in drilling of composite material. International Journal of Machine Tools and Manufacture, 44(10), 1085-1090. doi:10.1016/j.ijmachtools.2004.02.019Palanikumar, K., Prakash, S., & Shanmugam, K. (2008). Evaluation of Delamination in Drilling GFRP Composites. Materials and Manufacturing Processes, 23(8), 858-864. doi:10.1080/10426910802385026Mohan, N. S., Kulkarni, S. M., & Ramachandra, A. (2007). Delamination analysis in drilling process of glass fiber reinforced plastic (GFRP) composite materials. Journal of Materials Processing Technology, 186(1-3), 265-271. doi:10.1016/j.jmatprotec.2006.12.043Srinivasa Rao, B., Rudramoorthy, R., Srinivas, S., & Nageswara Rao, B. (2008). Effect of drilling induced damage on notched tensile and pin bearing strengths of woven GFR-epoxy composites. Materials Science and Engineering: A, 472(1-2), 347-352. doi:10.1016/j.msea.2007.03.023Enemuoh, E. U., El-Gizawy, A. S., & Chukwujekwu Okafor, A. (2001). An approach for development of damage-free drilling of carbon fiber reinforced thermosets. International Journal of Machine Tools and Manufacture, 41(12), 1795-1814. doi:10.1016/s0890-6955(01)00035-9Saravanan, M., Ramalingam, D., Manikandan, G., & Kaarthikeyen, R. R. (2012). Multi Objective Optimization of Drilling Parameters Using Genetic Algorithm. Procedia Engineering, 38, 197-207. doi:10.1016/j.proeng.2012.06.027Feito, N., Milani, A. S., & Muñoz-Sánchez, A. (2015). Drilling optimization of woven CFRP laminates under different tool wear conditions: a multi-objective design of experiments approach. Structural and Multidisciplinary Optimization, 53(2), 239-251. doi:10.1007/s00158-015-1324-yKrishnaraj, V., Prabukarthi, A., Ramanathan, A., Elanghovan, N., Senthil Kumar, M., Zitoune, R., & Davim, J. P. (2012). Optimization of machining parameters at high speed drilling of carbon fiber reinforced plastic (CFRP) laminates. Composites Part B: Engineering, 43(4), 1791-1799. doi:10.1016/j.compositesb.2012.01.007Krishnamoorthy, A., Rajendra Boopathy, S., Palanikumar, K., & Paulo Davim, J. (2012). Application of grey fuzzy logic for the optimization of drilling parameters for CFRP composites with multiple performance characteristics. Measurement, 45(5), 1286-1296. doi:10.1016/j.measurement.2012.01.008Abhishek, K., Datta, S., & Mahapatra, S. S. (2014). Optimization of thrust, torque, entry, and exist delamination factor during drilling of CFRP composites. The International Journal of Advanced Manufacturing Technology, 76(1-4), 401-416. doi:10.1007/s00170-014-6199-3El Kadi, H. (2006). Modeling the mechanical behavior of fiber-reinforced polymeric composite materials using artificial neural networks—A review. Composite Structures, 73(1), 1-23. doi:10.1016/j.compstruct.2005.01.020Altinkok, N., & Koker, R. (2004). Neural network approach to prediction of bending strength and hardening behaviour of particulate reinforced (Al–Si–Mg)-aluminium matrix composites. Materials & Design, 25(7), 595-602. doi:10.1016/j.matdes.2004.02.014Karnik, S. R., Gaitonde, V. N., Rubio, J. C., Correia, A. E., Abrão, A. M., & Davim, J. P. (2008). Delamination analysis in high speed drilling of carbon fiber reinforced plastics (CFRP) using artificial neural network model. Materials & Design, 29(9), 1768-1776. doi:10.1016/j.matdes.2008.03.014Altinkok, N., & Koker, R. (2006). Modelling of the prediction of tensile and density properties in particle reinforced metal matrix composites by using neural networks. Materials & Design, 27(8), 625-631. doi:10.1016/j.matdes.2005.01.005Stone, R., & Krishnamurthy, K. (1996). A neural network thrust force controller to minimize delamination during drilling of graphite-epoxy laminates. International Journal of Machine Tools and Manufacture, 36(9), 985-1003. doi:10.1016/0890-6955(96)00013-2Kuo, C.-F. J., Chang, C.-D., Su, T.-L., & Fu, C.-T. (2008). Optimization of the Dyeing Process and Prediction of Quality Characteristics on Elastic Fiber Blending Fabrics. Polymer-Plastics Technology and Engineering, 47(7), 678-687. doi:10.1080/03602550802129569Chen, W.-C., Fu, G.-L., Tai, P.-H., & Deng, W.-J. (2009). Process parameter optimization for MIMO plastic injection molding via soft computing. Expert Systems with Applications, 36(2), 1114-1122. doi:10.1016/j.eswa.2007.10.020Ko, Y.-D., Moon, P., Kim, C. E., Ham, M.-H., Myoung, J.-M., & Yun, I. (2009). Modeling and optimization of the growth rate for ZnO thin films using neural networks and genetic algorithms. Expert Systems with Applications, 36(2), 4061-4066. doi:10.1016/j.eswa.2008.03.010Faraz, A., Biermann, D., & Weinert, K. (2009). Cutting edge rounding: An innovative tool wear criterion in drilling CFRP composite laminates. International Journal of Machine Tools and Manufacture, 49(15), 1185-1196. doi:10.1016/j.ijmachtools.2009.08.002Ashrafi, H. R., Jalal, M., & Garmsiri, K. (2010). Prediction of load–displacement curve of concrete reinforced by composite fibers (steel and polymeric) using artificial neural network. Expert Systems with Applications, 37(12), 7663-7668. doi:10.1016/j.eswa.2010.04.076Levenberg, K. (1944). A method for the solution of certain non-linear problems in least squares. Quarterly of Applied Mathematics, 2(2), 164-168. doi:10.1090/qam/10666Khashaba, U. A., El-Sonbaty, I. A., Selmy, A. I., & Megahed, A. A. (2010). Machinability analysis in drilling woven GFR/epoxy composites: Part II – Effect of drill wear. Composites Part A: Applied Science and Manufacturing, 41(9), 1130-1137. doi:10.1016/j.compositesa.2010.04.011Heisel, U., & Pfeifroth, T. (2012). Influence of Point Angle on Drill Hole Quality and Machining Forces When Drilling CFRP. Procedia CIRP, 1, 471-476. doi:10.1016/j.procir.2012.04.084Díaz-Álvarez, A., Díaz-Álvarez, J., Santiuste, C., & Miguélez, M. H. (2019). Experimental and numerical analysis of the influence of drill point angle when drilling biocomposites. Composite Structures, 209, 700-709. doi:10.1016/j.compstruct.2018.11.01

A proposed testbed for detector tomography

Measurement is the only part of a general quantum system that has yet to be characterized experimentally in a complete manner. Detector tomography provides a procedure for doing just this; an arbitrary measurement device can be fully characterized, and thus calibrated, in a systematic way without access to its components or its design. The result is a reconstructed POVM containing the measurement operators associated with each measurement outcome. We consider two detectors, a single-photon detector and a photon-number counter, and propose an easily realized experimental apparatus to perform detector tomography on them. We also present a method of visualizing the resulting measurement operators.Comment: 9 pages, 4 figure

Numerical Modelling of Ballistic Impact Response at Low Velocity in Aramid Fabrics

[EN] In this study, the effect of the impact angle of a projectile during low-velocity impact on Kevlar fabrics has been investigated using a simplified numerical model. The implementation of mesoscale models is complex and usually involves long computation time, in contrast to the practical industry needs to obtain accurate results rapidly. In addition, when the simulation includes more than one layer of composite ply, the computational time increases even in the case of hybrid models. With the goal of providing useful and rapid prediction tools to the industry, a simplified model has been developed in this work. The model offers an advantage in the reduced computational time compared to a full 3D model (around a 90% faster). The proposed model has been validated against equivalent experimental and numerical results reported in the literature with acceptable deviations and accuracies for design requirements. The proposed numerical model allows the study of the influence of the geometry on the impact response of the composite. Finally, after a parametric study related to the number of layers and angle of impact, using a response surface methodology, a mechanistic model and a surface diagram have been presented in order to help with the calculation of the ballistic limit.This research was funded by the Ministry of Economy and Competitiveness from Spain, grant number BES-2012-055162 and the international collaborations subprogram under the reference EEBB-I-2016-11586.Feito-Sánchez, N.; Loya, J.; Muñoz-Sánchez, A.; Das, R. (2019). Numerical Modelling of Ballistic Impact Response at Low Velocity in Aramid Fabrics. Materials. 12(13):1-15. https://doi.org/10.3390/ma121320871151213Tabiei, A., & Nilakantan, G. (2008). Ballistic Impact of Dry Woven Fabric Composites: A Review. Applied Mechanics Reviews, 61(1). doi:10.1115/1.2821711Lim, C. ., Tan, V. B. ., & Cheong, C. . (2002). Perforation of high-strength double-ply fabric system by varying shaped projectiles. International Journal of Impact Engineering, 27(6), 577-591. doi:10.1016/s0734-743x(02)00004-0Tan, V. B. ., Lim, C. ., & Cheong, C. . (2003). Perforation of high-strength fabric by projectiles of different geometry. International Journal of Impact Engineering, 28(2), 207-222. doi:10.1016/s0734-743x(02)00055-6Shim, V. P. W., Tan, V. B. C., & Tay, T. E. (1995). Modelling deformation and damage characteristics of woven fabric under small projectile impact. International Journal of Impact Engineering, 16(4), 585-605. doi:10.1016/0734-743x(94)00063-3Park, Y., Kim, Y., Baluch, A. H., & Kim, C.-G. (2014). Empirical study of the high velocity impact energy absorption characteristics of shear thickening fluid (STF) impregnated Kevlar fabric. International Journal of Impact Engineering, 72, 67-74. doi:10.1016/j.ijimpeng.2014.05.007Taraghi, I., Fereidoon, A., & Taheri-Behrooz, F. (2014). Low-velocity impact response of woven Kevlar/epoxy laminated composites reinforced with multi-walled carbon nanotubes at ambient and low temperatures. Materials & Design, 53, 152-158. doi:10.1016/j.matdes.2013.06.051Nilakantan, G., Merrill, R. L., Keefe, M., Gillespie, J. W., & Wetzel, E. D. (2015). Experimental investigation of the role of frictional yarn pull-out and windowing on the probabilistic impact response of kevlar fabrics. Composites Part B: Engineering, 68, 215-229. doi:10.1016/j.compositesb.2014.08.033López-Gálvez, H., Rodriguez-Millán, M., Feito, N., & Miguelez, H. (2016). A method for inter-yarn friction coefficient calculation for plain wave of aramid fibers. Mechanics Research Communications, 74, 52-56. doi:10.1016/j.mechrescom.2016.04.004Duan, Y., Keefe, M., Bogetti, T. A., Cheeseman, B. A., & Powers, B. (2006). A numerical investigation of the influence of friction on energy absorption by a high-strength fabric subjected to ballistic impact. International Journal of Impact Engineering, 32(8), 1299-1312. doi:10.1016/j.ijimpeng.2004.11.005Cunniff, P. M. (1992). An Analysis of the System Effects in Woven Fabrics under Ballistic Impact. Textile Research Journal, 62(9), 495-509. doi:10.1177/004051759206200902Pan, N., Lin, Y., Wang, X., & Postle, R. (2000). An Oblique Fiber Bundle Test and Analysis. Textile Research Journal, 70(8), 671-674. doi:10.1177/004051750007000803Ha-Minh, C., Imad, A., Boussu, F., & Kanit, T. (2016). Experimental and numerical investigation of a 3D woven fabric subjected to a ballistic impact. International Journal of Impact Engineering, 88, 91-101. doi:10.1016/j.ijimpeng.2015.08.011Chocron Benloulo, I. S., Rodríguez, J., Martínez, M. A., & Sánchez Gálvez, V. (1997). Dynamic tensile testing of aramid and polyethylene fiber composites. International Journal of Impact Engineering, 19(2), 135-146. doi:10.1016/s0734-743x(96)00017-6Cheeseman, B. A., & Bogetti, T. A. (2003). Ballistic impact into fabric and compliant composite laminates. Composite Structures, 61(1-2), 161-173. doi:10.1016/s0263-8223(03)00029-1Rodriguez, J., Chocron, I. S., Martinez, M. A., & Sánchez-Gálvez, V. (1996). High strain rate properties of aramid and polyethylene woven fabric composites. Composites Part B: Engineering, 27(2), 147-154. doi:10.1016/1359-8368(95)00036-4Garcia, C., Trendafilova, I., & Zucchelli, A. (2018). The Effect of Polycaprolactone Nanofibers on the Dynamic and Impact Behavior of Glass Fibre Reinforced Polymer Composites. Journal of Composites Science, 2(3), 43. doi:10.3390/jcs2030043Garcia, C., & Trendafilova, I. (2019). Triboelectric sensor as a dual system for impact monitoring and prediction of the damage in composite structures. Nano Energy, 60, 527-535. doi:10.1016/j.nanoen.2019.03.070ARUNIIT, A., KERS, J., GOLJANDIN, D., SAARNA, M., TALL, K., MAJAK, J., & HERRANEN, H. (2011). Particulate Filled Composite Plastic Materials from Recycled Glass Fibre Reinforced Plastics. Materials Science, 17(3). doi:10.5755/j01.ms.17.3.593Ramaiah, G. B., Chennaiah, R. Y., & Satyanarayanarao, G. K. (2010). Investigation and modeling on protective textiles using artificial neural networks for defense applications. Materials Science and Engineering: B, 168(1-3), 100-105. doi:10.1016/j.mseb.2009.12.029Lopes, C. S., Seresta, O., Coquet, Y., Gürdal, Z., Camanho, P. P., & Thuis, B. (2009). Low-velocity impact damage on dispersed stacking sequence laminates. Part I: Experiments. Composites Science and Technology, 69(7-8), 926-936. doi:10.1016/j.compscitech.2009.02.009Duan, Y., Keefe, M., Bogetti, T. A., & Cheeseman, B. A. (2005). Modeling the role of friction during ballistic impact of a high-strength plain-weave fabric. Composite Structures, 68(3), 331-337. doi:10.1016/j.compstruct.2004.03.026Rao, M. P., Duan, Y., Keefe, M., Powers, B. M., & Bogetti, T. A. (2009). Modeling the effects of yarn material properties and friction on the ballistic impact of a plain-weave fabric. Composite Structures, 89(4), 556-566. doi:10.1016/j.compstruct.2008.11.012Nilakantan, G., Keefe, M., Wetzel, E. D., Bogetti, T. A., & Gillespie, J. W. (2011). Computational modeling of the probabilistic impact response of flexible fabrics. Composite Structures, 93(12), 3163-3174. doi:10.1016/j.compstruct.2011.06.013Nilakantan, G., & Gillespie, J. W. (2012). Ballistic impact modeling of woven fabrics considering yarn strength, friction, projectile impact location, and fabric boundary condition effects. Composite Structures, 94(12), 3624-3634. doi:10.1016/j.compstruct.2012.05.030Nilakantan, G., Wetzel, E. D., Bogetti, T. A., & Gillespie, J. W. (2012). Finite element analysis of projectile size and shape effects on the probabilistic penetration response of high strength fabrics. Composite Structures, 94(5), 1846-1854. doi:10.1016/j.compstruct.2011.12.028Nilakantan, G., Wetzel, E. D., Bogetti, T. A., & Gillespie, J. W. (2013). A deterministic finite element analysis of the effects of projectile characteristics on the impact response of fully clamped flexible woven fabrics. Composite Structures, 95, 191-201. doi:10.1016/j.compstruct.2012.07.023Nilakantan, G., & Nutt, S. (2014). Effects of fabric target shape and size on the V50 ballistic impact response of soft body armor. Composite Structures, 116, 661-669. doi:10.1016/j.compstruct.2014.06.002Grujicic, M., Bell, W. C., Arakere, G., He, T., & Cheeseman, B. A. (2009). A meso-scale unit-cell based material model for the single-ply flexible-fabric armor. Materials & Design, 30(9), 3690-3704. doi:10.1016/j.matdes.2009.02.008Grujicic, M., Arakere, G., He, T., Bell, W. C., Glomski, P. S., & Cheeseman, B. A. (2009). Multi-scale ballistic material modeling of cross-plied compliant composites. Composites Part B: Engineering, 40(6), 468-482. doi:10.1016/j.compositesb.2009.02.002Barauskas, R., & Abraitienė, A. (2007). Computational analysis of impact of a bullet against the multilayer fabrics in LS-DYNA. International Journal of Impact Engineering, 34(7), 1286-1305. doi:10.1016/j.ijimpeng.2006.06.002Ha-Minh, C., Boussu, F., Kanit, T., Crépin, D., & Imad, A. (2011). Analysis on failure mechanisms of an interlock woven fabric under ballistic impact. Engineering Failure Analysis, 18(8), 2179-2187. doi:10.1016/j.engfailanal.2011.07.011Ha-Minh, C., Imad, A., Kanit, T., & Boussu, F. (2013). Numerical analysis of a ballistic impact on textile fabric. International Journal of Mechanical Sciences, 69, 32-39. doi:10.1016/j.ijmecsci.2013.01.014Park, Y., Kim, Y., Baluch, A. H., & Kim, C.-G. (2015). Numerical simulation and empirical comparison of the high velocity impact of STF impregnated Kevlar fabric using friction effects. Composite Structures, 125, 520-529. doi:10.1016/j.compstruct.2015.02.041Chu, T.-L., Ha-Minh, C., & Imad, A. (2016). A numerical investigation of the influence of yarn mechanical and physical properties on the ballistic impact behavior of a Kevlar KM2 ® woven fabric. Composites Part B: Engineering, 95, 144-154. doi:10.1016/j.compositesb.2016.03.018Das, S., Jagan, S., Shaw, A., & Pal, A. (2015). Determination of inter-yarn friction and its effect on ballistic response of para-aramid woven fabric under low velocity impact. Composite Structures, 120, 129-140. doi:10.1016/j.compstruct.2014.09.063Nilakantan, G., & Gillespie, J. W. (2013). Yarn pull-out behavior of plain woven Kevlar fabrics: Effect of yarn sizing, pullout rate, and fabric pre-tension. Composite Structures, 101, 215-224. doi:10.1016/j.compstruct.2013.02.018Nilakantan, G., & Nutt, S. (2014). Effects of clamping design on the ballistic impact response of soft body armor. Composite Structures, 108, 137-150. doi:10.1016/j.compstruct.2013.09.017Rao, M. P., Nilakantan, G., Keefe, M., Powers, B. M., & Bogetti, T. A. (2009). Global/Local Modeling of Ballistic Impact onto Woven Fabrics. Journal of Composite Materials, 43(5), 445-467. doi:10.1177/0021998308097684Nilakantan, G., Keefe, M., Bogetti, T. A., Adkinson, R., & Gillespie, J. W. (2010). On the finite element analysis of woven fabric impact using multiscale modeling techniques. International Journal of Solids and Structures, 47(17), 2300-2315. doi:10.1016/j.ijsolstr.2010.04.029Nilakantan, G., Keefe, M., Bogetti, T. A., & Gillespie, J. W. (2010). Multiscale modeling of the impact of textile fabrics based on hybrid element analysis. International Journal of Impact Engineering, 37(10), 1056-1071. doi:10.1016/j.ijimpeng.2010.04.007Ha-Minh, C., Kanit, T., Boussu, F., & Imad, A. (2011). Numerical multi-scale modeling for textile woven fabric against ballistic impact. Computational Materials Science, 50(7), 2172-2184. doi:10.1016/j.commatsci.2011.02.029Lozano-Mínguez, E., Palomar, M., Infante-García, D., Rupérez, M. J., & Giner, E. (2018). Assessment of mechanical properties of human head tissues for trauma modelling. International Journal for Numerical Methods in Biomedical Engineering, 34(5), e2962. doi:10.1002/cnm.2962Palomar, M., Lozano-Mínguez, E., Rodríguez-Millán, M., Miguélez, M. H., & Giner, E. (2018). Relevant factors in the design of composite ballistic helmets. Composite Structures, 201, 49-61. doi:10.1016/j.compstruct.2018.05.076Moure, M. M., Feito, N., Aranda-Ruiz, J., Loya, J. A., & Rodriguez-Millan, M. (2019). On the characterization and modelling of high-performance para-aramid fabrics. Composite Structures, 212, 326-337. doi:10.1016/j.compstruct.2019.01.049Abtew, M. A., Boussu, F., Bruniaux, P., Loghin, C., & Cristian, I. (2019). Ballistic impact mechanisms – A review on textiles and fibre-reinforced composites impact responses. Composite Structures, 223, 110966. doi:10.1016/j.compstruct.2019.11096

Effect of ActiGraph\u27s Low Frequency Extension for Estimating Steps and Physical Activity Intensity

This study examined the effects of the ActiGraph’s (AG) low-frequency extension (LFE) filter on steps and physical activity classification in the free-living environment. Thirty-four African-American women (age, 24.5±5.2 years; BMI, 24.9±4.5 kg/m2) had daily activity measured simultaneously with an AG-GT3X+ accelerometer and a New Lifestyles NL-800 pedometer for seven days. Steps per day (steps/day) and time (minutes/day) spent in sedentary, light, and moderate-to-vigorous physical activity (MVPA) were examined with and without the LFE filter (AG-LFE and AG-N, respectively). The AG-LFE recorded more total steps (13,723±4,983 steps/day) compared to AG-N and NL-800 (6,172±2,838 and 5,817±3,037 steps/day, respectively; p\u3c0.001). Compared to the AG-N, the AG-LFE estimated less time in sedentary behaviors (518.7±92.1 vs. 504.2±105.4 min/day, respectively; p\u3c0.001), and more time in light (247.7±70.4 vs. 279.1±74.7 min/day, respectively; p\u3c0.001) and MVPA (18.9±16.9 vs. 21.5±18.2 min/day, respectively; p\u3c0.001), respectively. These data suggest that steps and physical activity classifications will be affected when using the ActiGraph with and without the LFE filter. Future research should investigate the accuracy of these measures using the LFE filter

Measuring Measurement: Theory and Practice

Recent efforts have applied quantum tomography techniques to the calibration and characterization of complex quantum detectors using minimal assumptions. In this work we provide detail and insight concerning the formalism, the experimental and theoretical challenges and the scope of these tomographical tools. Our focus is on the detection of photons with avalanche photodiodes and photon number resolving detectors and our approach is to fully characterize the quantum operators describing these detectors with a minimal set of well specified assumptions. The formalism is completely general and can be applied to a wide range of detectorsComment: 22 pages, 27 figure

Contributions of nursing students during their clinical practice in primary care: Adaptation and validation of a scale

Aim: To adapt the 'Nursing Student Contributions to Clinical Settings' scale (CEEEC, Spanish acronym), designed for specialized care and to evaluate the validity and reliability of a measure in the primary health care setting. Additionally, a description of the contributions of nursing students to primary health care in Spain is presented, based on the perception of preceptor nurses. Methods: A multicenter cross-sectional study was conducted in Spain, involving a committee of nursing experts who participated in a Delphi panel (n = 5) and cognitive interviews (n = 5) and a sample of nursing preceptors (n = 300) from 57 primary health care centers (2019-2020). The CEEEC was reviewed by experts for the conceptual semantic adequacy of the 24 items for its application in primary health care. Nurse preceptors' responses to the CEEEC scale were used to study the validity and reliability of the measure, including factor analysis, convergent validity with the Health Sciences-Evidence Based Practice scale and a matched test-retest over a three-week interval. Results: According to the consensus of experts, the CEEEC scale is valid for primary health care with minimal modifications (change "patient" to "user"). Based on the analysis of responses to the scale, the corrected item-total correlations of the 24 items were ≥ 0.40 and were grouped into a single factor, explaining 46.3% of the variance. The Cronbach's alpha value was 0.95. Regarding convergent validity, there was a positive correlation between the CEEEC scale and the score of the Health Sciences-Evidence Based Practice scale (Pearson's coefficient= 0.33; p < 0.001). The overall intraclass correlation coefficient was 0.91. Finally, the mean CEEEC score was 61.9 points (range 0-96). The two most positive contributions were 'Nursing students enable nursing professionals to perform their teaching role' and 'Nursing students become future professionals who know the healthcare facility'. Conclusions: The CEEEC scale provides a valid and reliable measure of nursing students' contributions to primary health care. Nursing students' contributions to Spanish primary health care were positive, especially towards the nursing profession and healthcare organizations.This work was supported by grants by Instituto de Salud Carlos III, Spanish State Secretary of R+D+I, Fondo Europeo de Desarrollo Regional (FEDER) and Fondo Social Europeo (FSE) [grant number PI18/00086] and Instituto de Investigación Sanitaria del Principado de Asturias (ISPA). The study funders had no role in the study design and in the collection, analysis, and interpretation of data, and the authors have sole responsibility for the manuscript content.S

Entanglement quantification from incomplete measurements: Applications using photon-number-resolving weak homodyne detectors

The certificate of success for a number of important quantum information processing protocols, such as entanglement distillation, is based on the difference in the entanglement content of the quantum states before and after the protocol. In such cases, effective bounds need to be placed on the entanglement of non-local states consistent with statistics obtained from local measurements. In this work, we study numerically the ability of a novel type of homodyne detector which combines phase sensitivity and photon-number resolution to set accurate bounds on the entanglement content of two-mode quadrature squeezed states without the need for full state tomography. We show that it is possible to set tight lower bounds on the entanglement of a family of two-mode degaussified states using only a few measurements. This presents a significant improvement over the resource requirements for the experimental demonstration of continuous-variable entanglement distillation, which traditionally relies on full quantum state tomography.Comment: 18 pages, 6 figure

On the experimental feasibility of continuous-variable optical entanglement distillation

Entanglement distillation aims at preparing highly entangled states out of a supply of weakly entangled pairs, using local devices and classical communication only. In this note we discuss the experimentally feasible schemes for optical continuous-variable entanglement distillation that have been presented in [D.E. Browne, J. Eisert, S. Scheel, and M.B. Plenio, Phys. Rev. A 67, 062320 (2003)] and [J. Eisert, D.E. Browne, S. Scheel, and M.B. Plenio, Annals of Physics (NY) 311, 431 (2004)]. We emphasize their versatility in particular with regards to the detection process and discuss the merits of the two proposed detection schemes, namely photo-detection and homodyne detection, in the light of experimental realizations of this idea becoming more and more feasible.Comment: 5 pages, 5 figures, contribution to conference proceeding