1,081 research outputs found
First Order Actions: a New View
We analyse systems described by first order actions using the Hamilton-Jacobi
(HJ) formalism for singular systems. In this study we verify that generalized
brackets appear in a natural way in HJ approach, showing us the existence of a
symplectic structure in the phase spaces of this formalism
Deformation induced martensite characterization in Fe-30%Ni-5%Cu alloy
Deformation induced martensite properties were examined according to existing martensite morphology, crystallography and formation temperatures for different prior austenite homogenization conditions in Fe-30%Ni-5%Cu alloy. Scanning electron microscope (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques were employed to investigation. Scanning electron microscope observations showed elongated deformation induced martensite morphology in the austenite phase of alloy. As well, after deformation martensite start temperatures (Ms) were determined as -101°C and -105°C from DSC measurements for different homogenization conditions. In addition, X-ray diffraction analysis revealed the face centred cubic (fcc) of austenite phases and body centred cubic (bcc) deformation induced martensite phases for all studied samples
Hamilton - Jacobi treatment of front-form Schwinger model
The Hamilton-Jacobi formalism was applied to quantize the front-form
Schwinger model. The importance of the surface term is discussed in detail. The
BRST-anti-BRST symmetry was analyzed within Hamilton-Jacobi formalism.Comment: 11 pages, to be published in Int. Journ. Mod. Phys.
Geometry Optimization Calculations for the Elasticity of Gold at High Pressure
We present embedded atom method based geometry optimization aspects of pressure effect on some elastic and mechanical properties of gold. During study, we determined the pressure dependency of equilibrium volume, typical cubic elastic constants, bulk modulus, shear modulus, young modulus, and elastic wave velocities of the considered metal with varying pressure between 0 GPa and 1000 GPa. Finally, we carried out a benchmark between our results and other available theoretical calculations and experimental data. The results of the study mutually agree with the previous findings and provide a deeper outlook for high pressure behavior of the studied metal
Hamilton-Jacobi quantization of singular Lagrangians with linear velocities
In this paper, constrained Hamiltonian systems with linear velocities are
investigated by using the Hamilton-Jacobi method. We shall consider the
integrablity conditions on the equations of motion and the action function as
well in order to obtain the path integral quantization of singular Lagrangians
with linear velocities.Comment: late
Opportunities in utilization of agricultural residues in bio-composite production: Corn stalk (Zea mays indurata Sturt) and oak wood (Quercus Robur L.) fiber in medium density fiberboard
In this paper, corn stalk as an agricultural residue was mixed with oak wood fiber to produce medium density fiberboards (MDF). Urea formaldehyde resin was used as binder. Hygroscopic and mechanical properties were evaluated according to the commercial standards in MDF production. Partial substitution of wood fiber with corn stalks fiber negatively affected all board properties. However, the mechanical properties fulfill the minimum requirements of the relevant standards such as TS-EN 310, 1999 and TS-EN 319, 1999. In some cases, they exceeded the standards, even with partial blending of corn stalk fibers.Key words: Corn stalks, Quercus robur, medium density fiberboard, physical and mechanical properties
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Rod photoreceptors drive circadian photoentrainment across a wide range of light intensities.
In mammals, synchronization of the circadian pacemaker in the hypothalamus is achieved through direct input from the eyes conveyed by intrinsically photosensitive retinal ganglion cells (ipRGCs). Circadian photoentrainment can be maintained by rod and cone photoreceptors, but their functional contributions and their retinal circuits that impinge on ipRGCs are not well understood. Using mice that lack functional rods or in which rods are the only functional photoreceptors, we found that rods were solely responsible for photoentrainment at scotopic light intensities. Rods were also capable of driving circadian photoentrainment at photopic intensities at which they were incapable of supporting a visually guided behavior. Using mice in which cone photoreceptors were ablated, we found that rods signal through cones at high light intensities, but not at low light intensities. Thus, rods use two distinct retinal circuits to drive ipRGC function to support circadian photoentrainment across a wide range of light intensities
Multi Hamilton-Jacobi quantization of O(3) nonlinear sigma model
The O(3) non-linear sigma model is investigated using multi Hamilton-Jacobi
formalism. The integrability conditions are investigated and the results are in
agreement with those obtained by Dirac's method. By choosing an adequate
extension of phase space we describe the transformed system by a set of three
Hamilton-Jacobi equations and calculate the corresponding action.Comment: 10 pages, LaTeX, to be published in Mod. Phys. Lett.
Effective Strategies for Protecting Human Rights: A Conference Engaging the International Community
Human rights protection needs teeth. And those who work in the disparate field of human rights need to see the system more comprehensively and strategically. Far too often, political issues interfere with enforcement of human rights laws and allow violators to hide behind the unwillingness of national governments to take action to enforce existing laws against human rights violators. Lack of commitment to human rights enforcement or timely preventative or intervention actions have led to violators being left unpunished for torture, rape and genocide. This failure of governments means that there is a lack of deterent power sufficient to inhibit potential human rights violators who know they will not be legally pursued after a conflict has ended
Performance and health of dairy calves fed limited amounts of acidified milk replacer
To compare growth performance of Brown Swiss calves fed acidified milk replacer (AMR) at 8% of birth weight, 20 newborn calves were reared under a new calf-feeding programme. Body weights, total weight gains and gains in body measurements, feed intake and feed efficiency values determined at different stages of growth of AMR-fed calves were comparable to those of calves fed sweet milk replacer (SMR). Faecal consistency scores and percent days with diarrhoea of calves offered AMR from four to 35 days of age were respectively 0.4 and 19.1% lower than those fed SMR. Most of the behavioural parameters studied were not unfavourably influenced by acidification of the replacer. In conclusion, growth, feed intake and feed efficiency characteristics of Brown Swiss calves fed AMR or SMR were not different from each other. However, incidence of diarrhoea of the young calves was decreased and health status of the calves was improved with the feeding of acidified milk. South African Journal of Animal Science Vol. 36(3) 2006: 149-15
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