Complete Coalescence, Partial Bounce and Rebound: Different Regimes Resulting from the Interaction of a Free Falling Drop with a Target Fluid

The interaction of a falling drop(diluted aqueous solution of ink in various concentrations)with a target fluid(partially degassed tap water)has been tracked by means of high-resolution video recording and photography.The experimental setup has carefully been prepared in order to preserve the axial symmetry of initial conditions.Three regimes of interaction have been identified accordingly(depending on the drop velocity as controlled by the distance of fall):rapid droplet coalescence,rebound with the conservation of the drop volume and shape,and partial coalescence.Previous findings are recovered and confirmed,and enriched with heretofore unseen observations of complex partial coalescence.An extensive set of data is reported to support understanding of the observed dynamics and their repeatability and reproducibility.The overall study has been carried out with the express intent to spur the future development of detailed mathematical models and numerical methods suited for this kind of problems.

Optimization design method of contact bounce and breakaway initial velocity for aerospace electromagnetic relay

Aerospace electromagnetic relay is an electric component that has been widely used in aerospace industry.Contact bounce and contact breakaway for initial velocity are the key parameters that have strong influence on reliability and electric life of the relay.Generally,it is difficult to optimize these two parameters simultaneously.In this paper,according to kinetics theory and structural mechanics,a dynamic reaction calculation model of the relay that describes contact bounce and breakaway for initial velocity is proposed.Under the constraints of contact gap and contact force,the optimal combination of debugging parameters is obtained by the application of orthogonal design.It considers the reduction of contact bounce and the augmentation of breakaway for initial velocity as the optimization objectives,and takes the debugging parameters as the optimization variables.All these above ensure the increase of contact breakaway for initial velocity and the decrease of contact bounce simultaneously,and contact arc erosion is also reduced.

Modified Ceiling Bounce Model for Computing Path Loss and Delay Spread in Indoor Optical Wireless Systems

This paper proposes modifications to the tradional Ceiling Bounce Model and uses it to characterize diffuse indoor optical wireless channel by analyzing the effect of transceiver position on signal propagation properties. The modified approach uses a combination of the tradional ceiling bounce method and a statistical approach. The effects of different transmitter-receiver separations and height of the ceiling on path loss and delay spread are studied in detail.

Some Tools to Model Ground or Supply Bounces Induced in and out of Heterogeneous Integrated Circuits

Electrical ground looks simple on a schematic; unfortunately, the actual performance of a circuit is dictated by its layout （and by its printed-circuit-board）. When the ground node moves, system performance suffers and the system radiates electromagnetic interferences. But the understanding of the physics of ground noise can provide an intuitive sense for reducing the problem. Ground bounce can produce transients with amplitudes of volts; most often changing magnetic flux is the cause; in this work, the authors use a Finite-Difference Time-Domain to begin to understand such phenomena. Additionally, predicting substrate cross-talks in mixed-signal circuits has become a critical issue to preserve signal integrity in future integrated systems. Phenomena that involve parasitic signal propagation into the substrate are discussed. A simple methodology to predict the substrate cross-talk and some associated tools are presented. Finally, the authors indicate a stochastic method which could grasp both outer or inner RF （Radio-Frequency） radiations and substrate parasites.

Cosmology with Bounce by Flat Space-Time Theory of Gravitation and a New Interpretation

General relativity predicts a singularity in the beginning of the universe being called big bang. Recent developments in loop quantum cosmology avoid the singularity and the big bang is replaced by a big bounce. A classical theory of gravitation in flat space-time also avoids the singularity under natural conditions on the density parameters. The universe contracts to a positive minimum and then it expands during all times. It is not symmetric with regard to its minimum implying a finite age measured with proper time of the universe. The space of the universe is flat and the total energy is conserved. Under the assumption that the sum of the density parameters is a little bit bigger than one the universe is very hot in early times. Later on, the cosmological model agrees with the one of general relativity. A new interpretation of a non-expanding universe may be given by virtue of flat space-time theory of gravitation.

Predicting the Curvature of the Cosmos, and Point of Volume Contraction in a Big Bounce Scenario

Based on the latest Planck surveys, the universe is close to being remarkably flat, and yet, within observational error, there is still room for a slight curvature. If the curvature is positive, then this would lead to a closed universe, as well as allow for a big bounce scenario. Working within these assumptions, and using a simple model, we predict that the cosmos may have a positive curvature in the amount, Ω0=1.001802, a value within current observational bounds. For the scaling laws associated with the density parameters in Friedmann’s equations, we will assume a susceptibility model for space, where, , equals the smeared cosmic susceptibility. If we allow the to decrease with increasing cosmic scale parameter, “a”, then we can predict a maximum Hubble volume, with minimum CMB temperature for the voids, before contraction begins, as well as a minimum volume, with maximum CMB temperature, when expansion starts. A specific heat engine model for the cosmos is also entertained for this model of a closed universe.

Gedanken Experiment for Energy, and Scale Factor, Based upon the Assumption of Quintessence and Idea of Quantum Bounce in Order to Isolate Admissible Frequency for Gravitational Waves in the Beginning of Cosmological Evolution

We initially look at a non-singular universe representation of time, and of comparing a general formula of a cosmological Potential energy as given by Padmanbhan, with Weinberg’s Quintessence Potential energy. Isolating a given time component which may serve as an introduction. We then compare this to when , and seeing what the time component then allows as far as available initial energy, the scale factor a(t) and ø, then finally admissible frequency, for Pre Planckian process generated Gravitational waves.

Electromagnetic scattering and imaging simulation of extremely large-scale sea-ship scene based on GPU parallel technology

Aiming to solve the bottleneck problem of electromagnetic scattering simulation in the scenes of extremely large-scale seas and ships,a high-frequency method by using graphics processing unit(GPU)parallel acceleration technique is proposed.For the implementation of different electromagnetic methods of physical optics(PO),shooting and bouncing ray(SBR),and physical theory of diffraction(PTD),a parallel computing scheme based on the CPU-GPU parallel computing scheme is realized to balance computing tasks.Finally,a multi-GPU framework is further proposed to solve the computational difficulty caused by the massive number of ray tubes in the ray tracing process.By using the established simulation platform,signals of ships at different seas are simulated and their images are achieved as well.It is shown that the higher sea states degrade the averaged peak signal-to-noise ratio(PSNR)of radar image.

单人Bounce荷载下楼盖结构加速度反应谱设计

Bounce指双脚不离地的人体上下往复运动,是一种常见的有节奏人致激励。采用先进的无线测力鞋垫技术收集了175条bounce荷载曲线,计算每条荷载曲线的单自由系统加速度反应谱,在此基础上提出了设计反应谱分段表达式,主要分为三段：对应bounce一阶主频范围2～3.5 Hz的第一平台段、对应二阶主频范围4～7 Hz的第二平台段以及对应高阶频率的下降段,由试验数据分析给出了两个平台段的不同保证率下的代表值以及下降段参数。文中给出了设计反应谱的详细使用步骤,并通过大跨楼盖试验模型验证了方法的准确性。

单人Bounce荷载的实验建模研究

Bounce指音乐会或体育比赛中常见的观众双脚不离地的身体有节奏的上下往复运动。利用测力板以及无线测力鞋垫,开展了单人在不同频率下的Bounce荷载的测试试验,共得到了109人次822条有效单人Bounce荷载记录。在此基础上,建立了Bounce荷载的傅里叶级数模型,给出了四阶动载因子和相位角的建议值,并与国外已有模型进行了对比分析。本文模型所模拟的Bounce荷载与实测荷载的时域特性相同,所引起的结构响应幅值一致,可供工程设计参考使用。

多人Bounce荷载下结构动力响应折减系数研究

体育比赛、演唱会中观众原地身体上下往复式的欢庆动作会引起Bounce荷载,是典型的有节奏人致动力荷载。该研究将考虑和不考虑人群协同性所计算出的结构响应的比值,定义为Bounce荷载下的结构动力响应折减系数,利用小组人群同步Bounce荷载的实测数据,研究了折减系数随人数、结构频率和阻尼比的变化规律,并提出了对应的设计曲线及表达式。应用于实际结构响应计算时,首先由反应谱法计算单人Bounce荷载下结构的动力响应,将其乘以总体重并考虑振型值影响后,再乘以对应的折减系数,即可实现考虑协同性的人群Bounce荷载下结构动力响应的快速计算,算例分析表明了上述步骤及所建议的折减系数的合理性。

Matter Bounce宇宙模型研究

通过描述宇宙学的发展历史和现状,指出大爆炸理论和暴涨理论虽然有许多优点,可以解释许多现象,但它们并不是完美无缺,无懈可击,仍然有一些无法解释的问题。而matter bounce宇宙模型是一个可以取代前两种理论的模型,可以得到与宇宙观测相吻合的结论,因此研究这个模型是非常有意义的。

Exploration of petrographic,elemental,and material properties of dynamic failure-prone coals

The purpose of this study is to explore how the geochemical and petrographic components of coal may impact its physical properties and how these correlate with a history of reportable dynamic failure in coal mines.Dynamic failure events,also termed bumps,bounces,or bursts,are the explosive failures of rock in a mining environment.These events occur suddenly and often with no warning,resulting in worker injury up to and including fatality in greater than 60%of reportable cases through the Mine Safety and Health Administration(MSHA).A database of variables was compiled using publicly available datasets,which includes compositional geographic,strength,and Hardgrove grindability index(HGI)data.Results indicated that bumping coals were less mature,lower in carbon,higher in oxygen,softer,and less well cleated than coals that did not bump.High liptinite content was found to correlate with higher average uniaxial compressive strength(UCS)values.However,no clear and direct correlation between UCS and dynamic failure status was observed.The findings of this study established that differences existed between coals that had versus had not experienced reportable dynamic failure accidents.These differences were inherent to the coal itself and were independent of mining-induced risk factors.Results further illuminated how compositional attribute of coal influenced physical properties and began to clarify potential links between geochemistry and dynamic failure status.Only through the better understanding of risk can more effective mitigating strategies be enacted.

A hybrid method of solving near-zone composite eletromagnetic scattering from targets and underlying rough surface

For composite electromagnetic(EM)scattering from rough surface and target above it in near-field condition,modified shooting and bouncing ray(SBR)method and integral equation method(IEM),which are analytic methods combined with two-scale model for rough surface,are proposed to solve the composite near-field scattering problems.And the modified method is verified in effectiveness and accuracy by comparing the simulation results with measured results.Finally,the composite near-fielding scattering characteristics of a slanted plane and rough water surface below are obtained by using the proposed methods,and the dynamic tendency of composite scattering characteristics versus near-fielding distance is analyzed,which may have practical contribution to engineering programs in need of radar targets near-field characteristics under extra-low-altitude conditions.

Multi-Bounce ATR-FTIR结合Gram-Schmidt正交化法计算烟用香精相似度

采集2种不同风格特征烟用香精的Multi-Bounce Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy(Multi-Bounce ATR-FTIR)指纹图谱,运用主成分分析法各筛选出30条光谱,结合Gram-Schmidt正交化方法,分别建立了2类不同风格特征烟用香精的相似度鉴别模型。使用鉴别模型对未知样品进行相似度计算,并评价使用效果。结果显示,当相似度高于90%时,可以判定属于同一类香精,且相似度越高,风格特征越接近;当相似度低于90%时,可以判定不属于同一类香精,且相似度越低,风格特征的差异越显著。

New hybridization of PO, SBR, and MoM for scattering by large complex conducting objects

As a marked extension of the traditional MoM-PO （method of moment-physical optics） hybrid method, a new hybridization of PO, SBR, and MoM （MoM-SBR/PO） is presented to calculate the multireflection contribution in the PO region efficiently by introducing the method of SBR based on RDN notion, which avoids the time-consuming iterative procedure and the choice of proper Green＇s function. As compared with the traditional MoM-PO hybrid method, the calculation efficiency of the proposed method is greatly improved, and its validity is verified by numerical results.

Multiverse Version of Penrose CCC Cosmology, and Enhanced Quantization Compared

We reduplicate the Book “Dark Energy” by M. Li, X.-D. Li, and Y. Wang, zero-point energy calculation with an unexpected “length” added to the “width” of a graviton wavefunction just prior to the entrance of “gravitons” to a small region of space-time prior to a nonsingular start to the universe. We compare this to a solution which worked out using Klauder Enhanced quantization, for the same given problem. The solution of the first Cosmological Constant problem relies upon the geometry of the multiverse generalization of CCC cosmology which is explained in this paper. The second solution used involves Klauder enhanced quantization. We look at energy given by our methods and compare and contrast it with the negative energy of the Rosen model for a mini sub-universe and estimate GW frequencies.

Constraints on Deceleration Parameter of a 5D Bounce Cosmological Model from Recent Cosmic Observations

We study the constraint on deceleration parameter q from the recent SNela Gold dataset and observational Hubble data by using a model-independent deceleration parameter q（z） = 1/2 - a/（1 ＋ z）^b under the flve-dimensional bounce cosmological model. For the cases of SNeIa Gold dataset, Hubble data, and their combination, the present results show that the constraints on transition redshift ZT are 0.35-0.07^＋0.14,0.68-0.58^＋1.47,and 0.55-0.09^＋0.18 with 1σ errors,respectively.

Landau damping of electrons with bouncing motion in a radio-frequency plasma

One-dimensional particle simulations have been conducted to study the interaction between a radio-frequency electrostatic wave and electrons with bouncing motion.It is shown that bounce resonance heating can occur at the first few harmonics of the bounce frequency(nω_(b),n=1,2,3,...).In the parameter regimes in which bounce resonance overlaps with Landau resonance,the higher harmonic bounce resonance may accelerate electrons at the velocity much lower than the wave phase velocity to Landau resonance region,enhancing Landau damping of the wave.Meanwhile,Landau resonance can increase the number of electrons in the lower harmonic bounce resonance region.Thus electrons can be efficiently heated.The result might be applicable for collisionless electron heating in low-temperature plasma discharges.

Observational constraints on the accelerating universe in the framework of a 5D bounce cosmological model

In the framework of a five-dimensional （5D） bounce cosmological model, a useful function f（z） is obtained by giving a concrete expression of deceleration parameter q（z） = q1 ＋q2/1＋1n（1＋z） Then using the obtained Hubble parameter H（z） according to the function f（z）, we constrain the accelerating universe from recent cosmic observations： the 192 ESSENCE SNe Ia and the 9 observational H（z） data. The best fitting values of transition redshift zT and current deceleration parameter q0 are given as zT =0.65-0.12^＋0.25 and q0=-0.76-0.15^＋0.15（1σ）. Furthermore, in the 5D bounce model it can be seen that the evolution of equation of state （EOS） for dark energy Wde can cross over -1 at about z = 0.23 and the current value W0de ： =-1.15 〈 -1. On the other hand, by giving a concrete expression of model-independent EOS of dark energy Wde, in the 5D bounce model we obtain the best fitting values zT = 0 .66-0.08^＋0.11 and q0=-0.69-0.10^＋0.10（1σ） from the recently observed data： the 192 ESSENCE SNe Ia, the observational H（z） data, the 3-year Wilkinson Microwave Anisotropy Probe （WMAP）, the Sloan Digital Sky Survey （SDSS） baryon acoustic peak and the x-ray gas mass fraction in clusters.