Search results for "force"

Strength and Ductility of Hollow Circular Steel Columns Filled with Fibre Reinforced Concrete

1999

Publisher Summary This chapter investigates the behavior of hollow circular steel cross-sections filled with Fiber Reinforced Concrete (FRC), subjected to monotonic loads. The casting of different types of composite members—steel columns, steel columns filled with Normal Strength Concrete (NSC), and steel columns filled with Fiber Reinforced Concrete (FRC) was employed. The columns were tested in uniaxial compression utilizing a universal testing machine operating in displacement control. The maximum strength of composite members filled with FRC was 20% higher than that recorded for steel pipes filled with FRC. After the peak load was reached, failure was due to the crushing of concrete and…

Casimir-Polder interaction energy between two atoms in uniformly accelerated motion

2013

Casimir Polder forces between two accelerating atoms and the Unruh effect

2010

The Casimir-Polder force between two atoms with equal uniform acceleration and separated by a constant distance R is considered. We show that, in the low-acceleration limit, while the near-zone R-6 behavior of the interatomic interaction energy is not changed by the acceleration of the atoms, the far-zone interaction energy decreases as R-5 instead of the well-known R-7 behavior for inertial atoms. Possibility of an indirect detection of the Unruh effect through measurements of the Casimir-Polder force between the two accelerating atoms is also suggested. We also consider a heuristic model for calculating the Casimir-Polder potential energy between the two atoms in the high-acceleration lim…

Study with surface electromyography, borg scale and rom upper trapezius, deltoid of the three portions (clavicular, acromial, spinal) and the latissi…

2017

The pathologies located at shoulder can be caused by misuse or continued implementation of a sporting practice or physical activity. These pathologies are second position in the ranking of Traumatologics and Orthopedic Clinicals (Windt, Koes, De Jong & Bouter, 1995). Shoulder’s muscle injuries can occur when the arm is in a position that exceeds normal, this fact is repeated in sport, may be the repetition of the hand signal of the inductor problem (Kapandji, 2006). Given the importance of muscle function of the shoulder joint, along the existing boom of new techniques in the specific muscle activation has been carried out an experimental study using a " Test neuro proprioceptive response "…

Nexus of Electrospun Nanofibers and Additive Processing—Overview of Wearable Tactical Gears for CBRNE Defense

2021

Due to complex nature of twenty-first century battlefield, soldiers must perform multiple tasks to protect nations while maintaining their own safety. Advances in technological innovations are critical to support such functionalities to enhance safety and security. Using nexus of electrospinning and additive processing, we present how recent developments can be used to produce new generation of protective fabrics with integrative force protection, sensing/detection of chemical, biological, radiological, nuclear, and high yield explosives (CBRNE), and biomedical functionalities. Although electrospinning has been in use for some time, the special blends and configurations of nanofibers, as de…

Die Dissoziationskonstanten von 2,2?-Dihydroxydiphenylmethanderivaten

1973

The pK-values of the first and second degree of dissociation of 2.2′-dihydroxy-5-methyl-3′.5′-dinitro-diphenylmethane, 2.2′-dihydroxy-5-methyl-5′-nitro-diphenylmethane and 2.2′-dihydroxy-5.5′-dimethyl-3′-nitro-diphenylmethane were determined in aqueous solution at 25°C spectrophotometrically. Comparing the observed pK-values with those of 2-methyl-4.6-dinitrophenol, 2-methyl-4-nitrophenol, 2.4-dimethyl-6-nitro-phenol and 2.4-dimethylphenol, we found a decrease of the values of pK1 and an increase of pK2. We explain this by the formation of an intramolecular hydrogen bridge which stabilizes the anion of the half dissociated form. This assumption is supported by the UV spectra.

Convective Roll Instabilities of Vertical Throughflow with Viscous Dissipation in a Horizontal Porous Layer

2009

Published version of an article from the journal: Transport in Porous Media. The original publication is available at Spingerlink. http://dx.doi.org/10.1007/s11242-009-9417-y The vertical throughflow with viscous dissipation in a horizontal porous layer is studied. The horizontal plane boundaries are assumed to be isothermal with unequal temperatures and bottom heating. A basic stationary solution of the governing equations with a uniform vertical velocity field (throughflow) is determined. The temperature field in the basic solution depends only on the vertical coordinate. Departures from the linear heat conduction profile are displayed by the temperature distribution due to the forced con…

Linear instability of mixed convection of cold water in a porous layer induced by viscous dissipation

2009

Accepted version of an article published in the journal: International Journal of Thermal Sciences, Elsevier Published version available on Science Direct: http://dx.doi.org/10.1016/j.ijthermalsci.2008.06.012 An analysis of linear stability of the stationary laminar Darcy flow in a horizontal porous layer is performed. The porous layer is saturated with cold water. The upper plane boundary is assumed to be subject to heat transfer with finite conductance to an environment at the temperature of maximum density of cold water. The lower plane boundary is adiabatic. Convective instabilities are caused by flow viscous dissipation, inducing a basic temperature distribution that decreases in the u…

Spatial correlations of vacuum fluctuations and the Casimir-Polder potential

2003

We calculate the Casimir-Polder intermolecular potential using an effective Hamiltonian recently introduced. We show that the potential can be expressed in terms of the dynamical polarizabilities of the two atoms and the equal-time spatial correlation of the electric field in the vacuum state. This gives support to an interesting physical model recently proposed in the literature, where the potential is obtained from the classical interaction between the instantaneous atomic dipoles induced and correlated by the vacuum fluctuations. Also, the results obtained suggest a more general validity of this intuitive model, for example when external boundaries or thermal fields are present.

Mixed‐valence trinuclear manganese clusters : Influence of the electronic transfer on the magnetic properties

1990

The magnetic behavior of mixed‐valence trinuclear clusters d4‐d4‐d5 is discussed on the basis of a model which takes into account valence delocalization and Heisenberg exchange. This model considers the competing effect between the electronic transfer and the localization of the extra electron due to an asymmetry of the triangular entity. The magnetic properties of the mixed‐valence oxo‐centered Mn(II)‐Mn(III)‐Mn(III) complexes formulated as Mn3O(O2CR)6L3 (R=Me, L=pyridine) are discussed on the basis of the developed model, supporting a significant intramolecular electron transfer. A comparison of these results to those previously reported by assuming a valence‐trapped model is given. Carlo…