Increasingly, with the data collected at the LHC we are confronted with the possible existence of flow in pp collisions. In this work, we show that PYTHIA 8 produces flowlike effects in events with ...multiple hard subcollisions due to color string formations between final partons from independent hard scatterings, the so-called color reconnection. We present studies of different identified hadron observables in pp collisions at 7 TeV. Studies have been done both for minimum bias and multiplicity intervals in events with and without color reconnection to isolate the flowlike effect.
The study and understanding of the details of proton-proton collisions is important since they are the benchmark for the comparison with heavy ion results. In the present work we have studied the ...ΔηΔφ correlations as a function of the event multiplicity and transverse sphericity in pp collisions at 7 TeV using the PYTHIA 8.180 generator. The results show large variation in the shape of the correlation as function of the sphericity and multiplicity indicating the importance of slicing the data in bins of both observables to better understand the complexity of the interactions. Motivated by the flow like patterns originated by color reconnection (CR), results with and without CR together with dihadron correlations are discussed.
The study and understanding of the details of proton-proton collisions is important since they are the benchmark for the comparison with heavy ion results. In the present work we have studied the ...Delta eta Delta varphi correlations as a function of the event multiplicity and transverse sphericity in pp collisions at radicals = 7 TeV using the PYTHIA 8.180 generator. The results show large variation in the shape of the correlation as function of the sphericity and multiplicity indicating the importance of slicing the data in bins of both observables to better understand the complexity of the interactions. Motivated by the flow like patterns originated by color reconnection (CR), results with and without CR together with dihadron correlations are discussed.
The use of phase change materials (PCMs) is one of the pathways for the storage of temporarily excessive energy from natural sources (solar) and industry for use at a more suitable later time. One of ...the materials with a high energy storage density is sodium acetate trihydrate (SAT), on which several studies were conducted in order to solve phase segregation and supercooling problems, e.g. by adding polymers and nucleating agents. Here we investigate the effectiveness of adding a polymer blend of carboxymethyl cellulose (CMC) and silica gel to avoid phase segregation, and silver nanoparticles (AgNPs) as nucleating agent. The synthesis of silver nanoparticles was carried out by a green method in CMC as a way to ensure compatibility with SAT. The addition of AgNPs in higher concentrations to 0.5% reduces supercooling, and mixing silica gel with CMC to avoid segregation phase, yields an increment in the stability of the phase change behavior, during heating and cooling cycles. The latent heat release upon crystallization of the PCM was optimum for the mixture with 0.5% AgNPs, and for the highest amounts of CMC with respect to silica gel, with nearly 95% of latent heat recovery compared to pure SAT.
•The addition of silver nanoparticles reduced the supercooling of PCM.•Thermal properties of the PCM are improved with a blend of polymers.•The latent heat recovery of the PCM is higher with silver nanoparticles.•The combination of Polymers and silver nanoparticles reduces the segregation phase.
Chaotic oscillators have been implemented with a wide variety of discrete electronic devices and quite few realizations using integrated circuit technology. This article describes the synchronization ...of two chaotic oscillators already fabricated with complementary metal-oxide-semiconductor (CMOS) integrated circuit technology of 0.5um and generating 3- and 5-scrolls. In order to attain the synchronization, we use a master-slave topology with unidirectional coupling. Within this context, a system parameter iterates until the correlation coefficient computed between the chaotic signals generated by the master and slave systems approximates to unity. For the following parameter, its value depends on the standard deviations from the individual signals contrary to previous one. By combining those statistical relationships according to the number of system parameters, we can synchronize integrated chaotic oscillators. Theoretical model simulations of two chaotic oscillators generating 3- and 5-scrolls, and experimental results for two integrated 3-scroll chaotic oscillators validate this approach. Stability and error analysis are also included.
Los osciladores caóticos se han implementado con una variedad amplia de dispositivos electrónicos discretos y muy pocos con tecnología de circuitos integrados. Este artículo describe la sincronización de dos osciladores caóticos fabricados con tecnología de circuitos integrados CMOS de 0.5um que generan 3- y 5-enrollamientos. Se utiliza la configuración maestro-esclavo para obtener la sincronización. A partir de esta configuración, se itera un parámetro del sistema hasta que el coeficiente de correlación entre las señales caóticas del maestro y el esclavo respectivamente, se aproxima a la unidad. Posteriormente, se calcula la razón de las desviaciones estándar para obtener el valor del siguiente parámetro, esto de forma inversa a la determinación del primero. Es posible sincronizar osciladores caóticos integrados al combinar estas medidas estadísticas en relación al número de parámetros del sistema. Simulaciones del modelo teórico de dos osciladores caóticos exhibiendo tres y cinco enrollamientos, además de resultados experimentales para tres enrollamientos confirman el método propuesto. Son incluidos los análisis de error y estabilidad.
This paper proposes a new chaotic cryptosystem for the encryption of very high-resolution digital images based on the design of a digital chaos generator by using arbitrary precision arithmetic. This ...can be taken as an alternative to reduce the dynamic degradation that chaotic models present when they are implemented in digital devices and to increase the security of the cryptosystems. The obtained results show that when using high-precision arithmetic, the generated sequences provide good randomness and security during a greater number of iterations of the implemented chaotic maps in comparison with the generated sequences by using the standard of simple precision or double precision according to the IEEE 754 standard for floating-point arithmetic. The proposed method does not require high-cost hardware for increasing the numerical accuracy and security. As an advantage versus other recent works, using high precision, in relation to the methods that use simple precision or double precision, it awards an exponential increase in the key space. In this manner, it is demonstrated that using multiple-precision arithmetic, a key space of
2
33
,
268
or higher can be obtained, depending on the level of high precision configured. The security analysis confirms that the proposed chaotic cryptosystem is secure and robust against several known attacks, as well as statistical tests of NIST and TestU01, proving that high-precision arithmetic helps to enhance the security of the cryptosystems.
Multiscroll chaotic attractors generated by irregular saturated nonlinear functions with optimized positive Lyapunov exponent are designed and implemented. The saturated nonlinear functions are ...designed in an irregular way by modifying their parameters such as slopes, delays between slopes, and breakpoints. Then, the positive Lyapunov exponent is optimized using the differential evolution algorithm to obtain chaotic attractors with 2 to 5 scrolls. We observed that the resulting chaotic attractors present more complex dynamics when different patterns of irregular saturated nonlinear functions are considered. After that, the optimized chaotic oscillators are physically implemented with an analog discrete circuit to validate the use of proposed irregular saturated functions. Experimental results are consistent with MATLAB™ and SPICE circuit simulator. Finally, the synchronization between optimized and nonoptimized chaotic oscillators is demonstrated.
In this work, the impulsive stimulated scattering technique, in a heterodyne diffraction detection configuration (ISS-HD), was used to study the dependence of the speed of sound and the thermal ...diffusivity on the concentration of silver nanoparticles in water, to which also
d
-glucose and carboxymethyl cellulose were added, in order to reduce sedimentation. The ISS-HD results, which show a slight increase of thermal diffusivity with increasing concentration, were cross-validated with results obtained by the inverse photopyroelectric method and the hot ball technique.
► A multiscroll chaotic oscillator is fabricated with integrated circuit technology. ► The oscillator is based on a V–I comparator designed with FGMOS transistors. ► The advantage of the tested ...circuit is the elimination of external DC references. ► Experimental observation of 3- and 5-scroll attractors is provided. ► Experimental results are in good agreement with theoretical ones.
This paper introduces the experimental realization of the first integrated circuit of a multi-scroll continuous chaotic oscillator showing 3- and 5-scroll attractors. It is based on a variant of the Chua’s system. The most relevant issue is the implementation of a saw-tooth-like nonlinear function, which is designed by using floating gate MOS (FGMOS) transistors. Therefore, the realization of a voltage-to-current nonlinear cell by a piecewise-linear approach allows us to have only two external control inputs instead of numerous external voltage references, as usually done in current circuit realizations. Experimental results of the proposed integrated multi-scroll oscillator along with its corner analysis are provided.
PDF
