662 research outputs found
Exterior Differentials in Superspace and Poisson Brackets
It is shown that two definitions for an exterior differential in superspace,
giving the same exterior calculus, yet lead to different results when applied
to the Poisson bracket. A prescription for the transition with the help of
these exterior differentials from the given Poisson bracket of definite
Grassmann parity to another bracket is introduced. It is also indicated that
the resulting bracket leads to generalization of the Schouten-Nijenhuis bracket
for the cases of superspace and brackets of diverse Grassmann parities. It is
shown that in the case of the Grassmann-odd exterior differential the resulting
bracket is the bracket given on exterior forms. The above-mentioned transition
with the use of the odd exterior differential applied to the linear even/odd
Poisson brackets, that correspond to semi-simple Lie groups, results,
respectively, in also linear odd/even brackets which are naturally connected
with the Lie superalgebra. The latter contains the BRST and anti-BRST charges
and can be used for calculation of the BRST operator cohomology.Comment: 12 pages, LATEX 2e, JHEP format. Correction of misprints. The titles
for some references are adde
Resource-efficient technology to produce 4-aminodiphenylamine
A critical analysis of the existing and emerging methods for preparation of 4-aminodiphenylamine has been conducted. It is noted that, in economic and environmental terms, the promising methods are based on condensation of aniline with nitrobenzene in an alkaline medium, followed by hydrogenation of the resulting intermediates. Using the above method for industrial production of 4-ADPA will help eliminate principal shortcomings inherent in the existing industrial methods: reduce unit operations of the process, use more accessible, inexpensive raw materials, increase product yield, eliminate formation of carcinogenic substances, significantly decrease the formation of waste products and, most importantly, decrease the volume of waste water. The most promising methods for industrial production are recent discoveries that use heterogeneous catalysts during condensation of aniline with nitrobenzene, e.g., zeolite ZSM-5 treated with tetramethylammonium hydroxide or highly basic anions which considerably simplify production technology and process control, lower costs and comply with strict environmental requirements
Spin Seebeck effect in Y-type hexagonal ferrite thin films
Spin Seebeck effect (SSE) has been investigated in thin films of two
Y-hexagonal ferrites BaZnFeO (Zn2Y) and
BaCoFeO (Co2Y) deposited by a spin-coating method on
SrTiO(111) substrate. The selected hexagonal ferrites are both
ferrimagnetic with similar magnetic moments at room temperature and both
exhibit easy magnetization plane normal to -axis. Despite that, SSE signal
was only observed for Zn2Y, whereas no significant SSE signal was detected for
Co2Y. We tentatively explain this different behavior by a presence of two
different magnetic ions in Co2Y, whose random distribution over octahedral
sites interferes the long range ordering and enhances the Gilbert damping
constant. The temperature dependence of SSE for Zn2Y was measured and analyzed
with regard to the heat flux and temperature gradient relevant to the SSE
signal.Comment: 7 pages, 9 figure
Resistance of crucifers to root maggot complex, Delia spp. (Diptera: Anthomyiidae)
Non-Peer ReviewedIn field tests conducted at Saskatoon, Melfort, Scott, and Shellbrook, crucifer species differed in their levels of damage from crucifer-feeding root maggots of the Delia species complex. Sinapis alba was less injured than B. carinata, B. rapa, B. juncea, or B. napus. Root diameter may play a part in this difference in susceptibility. Differences in root injury levels within species occurred frequently, but were less consistent than among species. Location and year strongly influenced maggot infestation and damage levels
Hodge Duality Operation And Its Physical Applications On Supermanifolds
An appropriate definition of the Hodge duality operation on any
arbitrary dimensional supermanifold has been a long-standing problem. We define
a working rule for the Hodge duality operation on the -dimensional supermanifold parametrized by a couple of even (bosonic)
spacetime variables and a couple of Grassmannian (odd)
variables and of the Grassmann algebra. The Minkowski
spacetime manifold, hidden in the supermanifold and parametrized by , is chosen to be a flat manifold on which a two -dimensional
(2D) free Abelian gauge theory, taken as a prototype field theoretical model,
is defined. We demonstrate the applications of the above definition (and its
further generalization) for the discussion of the (anti-)co-BRST symmetries
that exist for the field theoretical models of 2D- (and 4D) free Abelian gauge
theories considered on the four - (and six )-dimensional
supermanifolds, respectively.Comment: LaTeX file, 25 pages, Journal-versio
Математичне моделювання електропідсилювача керма транспортного засобу з черв’ячною передачею
The complexity and variety of requirements imposed on modern cars have led to a variety of designs of steering amplifiers, which are based on various physical phenomena and patterns (mechanical, pneumatic, hydraulic, electrical, etc.). Despite the difference in design and operating principles, steering amplifiers of domestic and foreign production are based on a large number of complex components and parts, which reduces their reliability. In addition, due to the constant impact of amplifiers on the controlled wheels, the driver does not feel changes in the behavior of the car on the road when disturbing influences occur, which reduces traffic safety and can lead to an accident. Therefore, increasing the sensitivity of the steering wheel to adverse factors acting on the wheels of the car while driving is one of the important tasks of improving power steering system.
Introduction of electric power steering systems for cargo and passenger vehicles with a load capacity of up to 20 tons. this is a very urgent problem. In contrast to power steering system, which is still used in the control systems of high-tonnage vehicles, electric power is much simpler in design, does not require much time and costs for operation and repair.
Electric power steering system with worm drive, which has a gear ratio significantly higher than those used in passenger cars, is considered. For this purpose, the formula for calculating the active moment of resistance due to the angle of transverse inclination of the pin and the corresponding system of differential equations characterizing the electric power steering system with worm drive are derived. Based on this, a functional diagram of the electric power steering control system has been developed, which is unified for worm drive steering systems and can serve as a base for modeling the steering system of cargo and passenger vehicles.Перераховані переваги електропідси-лювача в порівнянні з гідропідсилювачем керма. Наведено можливі компонування електропідсилювача керма. Виведена формула для розрахунку активного моменту опору, обумовленого кутом поперечного нахилу шворня. Дана система диференціальних рівнянь, що характеризують електропідсилювач керма з черв’ячною передачею. Зображена функціональна схема електро-підсилювача керма
Why mainstream parties change policy on migration: A UK case study - The Conservative Party, immigration and asylum, 1960-2010
Measurement of Muon Capture on the Proton to 1% Precision and Determination of the Pseudoscalar Coupling g_P
The MuCap experiment at the Paul Scherrer Institute has measured the rate L_S
of muon capture from the singlet state of the muonic hydrogen atom to a
precision of 1%. A muon beam was stopped in a time projection chamber filled
with 10-bar, ultra-pure hydrogen gas. Cylindrical wire chambers and a segmented
scintillator barrel detected electrons from muon decay. L_S is determined from
the difference between the mu- disappearance rate in hydrogen and the free muon
decay rate. The result is based on the analysis of 1.2 10^10 mu- decays, from
which we extract the capture rate L_S = (714.9 +- 5.4(stat) +- 5.1(syst)) s^-1
and derive the proton's pseudoscalar coupling g_P(q^2_0 = -0.88 m^2_mu) = 8.06
+- 0.55.Comment: Updated figure 1 and small changes in wording to match published
versio
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