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Introduction With similar prevalence to injuries from fires, stings, and natural disasters, soft tissue injuries may occur from fireworks, industrial accidents, or other explosives. Surgeons are less familiar with treating high-velocity penetration from small debris, which may increase the chance of infection and subsequent fatality. Penetration risk curves have been developed to predict V50, the velocity with 50% probability of penetration, for various sized projectiles. However, there has been limited research using nonmetallic materials to achieve lower density projectiles less than 1 g cm−2, such as sand or rocks. Material and Methods To emulate the size and density of these energized particles, 14 ball bearings of stainless steel, silicon nitride, or Delrin acetal plastic ranging from 1.59 mm (1/16") to 9.53 mm (3/8") with sectional densities between 0.3 g cm−2 and 5  g cm−2 were launched toward porcine legs at a range of velocities to determine the penetration thresholds. High-speed videography was captured laterally at 40 kHz and impact velocity was captured using a physics-based tracking software. A generalized linear model with repeated measures and a logit link function was used to predict probability of penetration for each projectile. A total of 600 impacts were conducted to achieve at least 15 penetrating impacts for each projectile over a range of velocities. Results Higher impact velocities were required to penetrate the skin as sectional density of the projectile decreased, and the relationship between velocity and sectional density exhibited an exponential relationship (V 50, |$ = 184.6*S{D^{ - 0.385}}$|⁠ , R 2 = 0.95) with substantial change for nonlinearity in sectional densities ranging from 0.3 g cm−2 to 1  g cm−2. Compared to previous studies, the empirical relationship was consistent in the linear region (2-5  g cm−2), and novel experimentation filled in the gaps for sectional densities less than 1  g cm−2, which expressed more nonlinearity than previously estimated. For low-density projectiles with diameters of 1.59 (1/16") or 3.18 (1/8"), 32 impacts were lodged into the epidermis but did not penetrate through the dermis; however, penetration was defined as displacement into or through the dermis. Conclusions These experimental results may be used to develop and validate finite element simulations of low-density projectile impacts to address complex, multivariate loading conditions for the development of protective clothing to reduce wounding and subsequent infection rates. [ABSTRACT FROM AUTHOR]

The solutions of a nonlinear Schrödinger equation containing the nonlinear interaction b| ϕ|2 ϕ and center potential are found using the new method of separation of functions, in which the two wave functions satisfy the soluble and different equations, respectively. Its solution is still a soliton, which possesses both corpuscle and wave feature, its eigenenergy is still determinant and quantized, but its size of eigenenergy is depressed about A0′2 b/2 relative to that in linear case. This means that the localized nature of the particles described by the nonlinear Schrödinger equation with a center potential is enhanced due to the nonlinear interaction. This is first time to obtain the soliton solution of the nonlinear Schrödinger equation, which has an important significance and application in the nonlinear science, physics, chemistry, biology and engineering. [ABSTRACT FROM AUTHOR]

The unparticle field operator can be expanded in terms of creation and destruction operators corresponding to particles with a continuous mass spectrum. Hence, when the four-momentum of an unparticle is measured, then the unparticle manifests as an ordinary particle with a definite (but arbitrary) mass. [ABSTRACT FROM AUTHOR]

The effects of small vibrations on particle motion in a viscous fluid cell have been investigated experimentally and theoretically. A steel particle was suspended by a thin wire at the center of a fluid cell, and the cell was vibrated horizontally using an electro-magnetic actuator and an air bearing stage. The vibration-induced particle amplitude measurements were performed for different fluid viscosities (58.0 cP and 945 cP), and cell vibration amplitudes and frequencies. A viscous fluid model was also developed to predict the vibration-induced particle motion. This model shows the effect of fluid viscosity compared to the inviscid model, which was presented earlier by Hassan et al. (2004, "The Effects of Vibrations on Particle Motion in an Infinite Fluid Cell," ASME J. Appl. Mech., 73(1), pp. 72-78) and validated using data obtained for water. The viscous model with modified drag coefficients is shown to predict well the particle amplitude data for the fluid viscosities of 58.5 cP and 945 cP. While there is a resonance frequency corresponding to the particle peak amplitude for oil (58.0 cP), this phenomenon disappeared for glycerol (945 cP). This disappearance of resonance phenomenon is explained by referring to the theory of mechanical vibrations of a mass-spring-damper system. For the sinusoidal particle motion in a viscous fluid, the effective drag force has been obtained, which includes the virtual mass force, drag force proportional to the velocity, and the Basset or history force terms. [ABSTRACT FROM AUTHOR]

A common understanding of quantum mechanics (QM) among students and practical users is often plagued by a number of “myths”, that is, widely accepted claims on which there is not really a general consensus among experts in foundations of QM. These myths include wave-particle duality, time-energy uncertainty relation, fundamental randomness, the absence of measurement-independent reality, locality of QM, nonlocality of QM, the existence of well-defined relativistic QM, the claims that quantum field theory (QFT) solves the problems of relativistic QM or that QFT is a theory of particles, as well as myths on black-hole entropy. The fact is that the existence of various theoretical and interpretational ambiguities underlying these myths does not yet allow us to accept them as proven facts. I review the main arguments and counterarguments lying behind these myths and conclude that QM is still a not-yet-completely-understood theory open to further fundamental research. [ABSTRACT FROM AUTHOR]

Abstract: This study focuses on spherical microparticles made of cross-linked alginate gel and microcapsules composed of an oil-in-water emulsion where the continuous aqueous phase is cross-linked into an alginate gel matrix. We have investigated the use of these easily manufactured microbeads as contrast agents for the study of the flow properties of fluids using nuclear magnetic resonance imaging. Results demonstrate that combined spin–spin (T 2) relaxation and diffusion contrast in proton NMR imaging can be used to distinguish among rigid polymer particles, plain alginate beads, and alginate emulsion beads. Multi-echo CPMG spin-echo imaging indicates that the average spin–lattice (T 1) and spin–spin (T 2) relaxation times of the plain alginate and alginate emulsion beads are comparable. Meanwhile, diffusion-weighted imaging produces sharp contrast between the two types of alginate beads, due to restricted diffusion inside the embedded oil droplets of the alginate emulsion beads. While the signal obtained from most materials is severely attenuated under applied diffusion gradients, the alginate emulsion beads maintain signal strength. The alginate emulsion beads were added to a suspension and imaged in an abrupt, annular expansion flow. The emulsion beads could be clearly distinguished from the surrounding suspending fluid and rigid polystyrene particles, through either T 2 relaxation or diffusion contrast. Such a capability allows future use of the alginate emulsion beads as tracer particles and as one particle type among many in a multimodal suspension where detailed concentration profiles or particle size separation must be quantified during flow. [Copyright &y& Elsevier]

Why do photons and speeding electrons have both wave features and particle features when common sense tells us that they should be either particle or wave and not an amalgam of both? Part I of this paper deals with photons and argues that there are flaws in the assumptions we have made regarding their particle nature. The argument depends upon distinguishing between two identities of the photon, namely unstored energy and its stored (relativistic) mass. Part II extends these arguments to the case of the speeding electron and argues that current ontological assumptions made about projectiles have exacerbated our confusion about the nature of moving electrons. When regarded ontologically, projectile motion is not as simple as has been assumed by both classical and modern physics. [See also the author's www.einsteinsmethod.com.] [ABSTRACT FROM AUTHOR]

The adhesion of spheroidal particles to spherical drops is calculated and discussed in terms of an equilibrium-penetration index. The present study emphasizes the case of particles that are sufficiently large to affect the drop volume upon penetration. It is shown that the more elongated the particles, the steeper the dependence of the penetration index on the contact angle. The effect of line tension on nanoscale particles is considered. Positive line tensions increase the steepness of the dependence of penetration index on contact angle whereas negative line tensions decrease this dependence. In addition, the energy barrier caused by positive line tensions is presented and discussed. [ABSTRACT FROM AUTHOR]