On steady compressible flows with compact vorticity; the compressible Stuart vortex

Numerical and analytical solutions to the steady compressible Euler equations corresponding to a compressible analogue of the linear Stuart vortex array are presented. These correspond to a homentropic continuation, to finite Mach number, of the Stuart solution describing a linear vortex array in an incompressible fluid. The appropriate partial differential equations describing the flow correspond to the compressible homentropic Euler equations in two dimensions, with a prescribed vorticity–density–streamfunction relationship. In order to construct a well-posed problem for this continuation, it was found, unexpectedly, to be necessary to introduce an eigenvalue into the vorticity–density–streamfunction equation. In the Rayleigh–Janzen expansion of solutions in even powers of the free-stream Mach number M[infty infinity], this eigenvalue is determined by a solvability condition. Accurate numerical solution by both finite-difference and spectral methods are presented for the compressible Stuart vortex, over a range of M[infty infinity], and of a parameter corresponding to a confined mass-flow rate. These also confirm the nonlinear eigenvalue character of the governing equations. All solution branches followed numerically were found to terminate when the maximum local Mach number just exceeded unity. For one such branch we present evidence for the existence of a very small range of M[infty infinity] over which smooth transonic shock-free flow can occur

Cultural Approach to Reduced Traffic Accident in Bali

Safety on traveling is needed by all travelers. Safety on traveling is determined bymany factors such as the drivers, vehicles, road, environment and it relation each other.Balinese culture which influence by Hinduism, believe that traffics accidents occurred asa result of not harmonize the relation between human as a driver to vehicle or car, humanto the god and human to the environment. So in Balinese daily of life there is an effort toharmonize the relation of all components using cultural approach. In doing that manyactivities such as doing an offering to the new or after reparation of car, to offer sajen inthe car everyday during traveler, every 210 days during “ tumpek landep day” aftercleaning the car offer sajen, ring the bell or offer sajen during passing the sacral place ortemple, offer sajen and look after during night where the accident were happen, offersajen (mlaspas) the new road, forbidden to travel during wedding ceremony or get familydied. These activities mean to making the tools more humane so that the tools harmonizeto the user, forgive to the magic spirit around the road. By practicing the culturalapproach the traffic accident at many places can be reduced. One taxi company shownthat annually maintenance cost lower compared than the same company in Java

A note on the improvement ambiguity of the stress tensor and the critical limits of correlation functions

I study various properties of the critical limits of correlators containing insertions of conserved and anomalous currents. In particular, I show that the improvement term of the stress tensor can be fixed unambiguously, studying the RG interpolation between the UV and IR limits. The removal of the improvement ambiguity is encoded in a variational principle, which makes use of sum rules for the trace anomalies a and a'. Compatible results follow from the analysis of the RG equations. I perform a number of self-consistency checks and discuss the issues in a large set of theories.Comment: 15 page

Steady compressible vortex flows: the hollow-core vortex array

We examine the effects of compressiblity on the structure of a single row of hollowcore, constant-pressure vortices. The problem is formulated and solved in the hodograph plane. The transformation from the physical plane to the hodograph plane results in a linear problem that is solved numerically. The numerical solution is checked via a Rayleigh-Janzen expansion. It is observed that for an appropriate choice of the parameters M[infty infinity] = q[infty infinity]/c[infty infinity], and the speed ratio, a = q[infty infinity]/qv, where qv is the speed on the vortex boundary, transonic shock-free flow exists. Also, for a given fixed speed ratio, a, the vortices shrink in size and get closer as the Mach number at infinity, M[infty infinity], is increased. In the limit of an evacuated vortex core, we find that all such solutions exhibit cuspidal behaviour corresponding to the onset of limit lines

Comparison Study in Using Plough, Tractor and Cultivator for Rice Field\u27 Land Preparation

Land preparation of the rice field is one of the most important steps for paddyplantation. Formerly plough is one of the main tools for land preparation, but now thefarmer used tractor or cultivator. From the farmer experience who are used that tools forland preparation there had advantages and disadvantages. The used of plough for landpreparation for long time ago the deep of rice field soil is constant because the ploughblade can be adjusted up and down. The plough can be turn to the right or left side so thatall part of rice field except the corner can be cultivate. But for pulling the plough must bedifficult to find two cows. While if using tractor or cultivator the right or left side and thecorner of the rice field can\u27t be cultivate. Deep of rice filed soil become shallow so thefertility of soil reduced. Beside that using tractor or cultivator for land preparation needmore fuel. The plough were easy to carry out, but tractor and cultivator difficult to carryout because the weight more that 200 kg

Vacancy-Impurity Nanoclusters in Solid Solutions 3He−4He^3He - ^4He

The existence of vacancy--impurity clusters due to quantum properties of vacancies in phase separated solid solutions of 4He in 3He is analyzed and discussed. Additional mechanism called vacancy assisted nucleation is proposed. According to this assumption the vacancy-impurity clusters should have b.c.c. structure.Comment: 5 pages, 1 figure, Late

Time Modulation of K-electron Capture Decay of Hydrogen-Like Ions with Multiphoton Resonance Transitions

The multiphoton resonance transitions between ground hyperfine states are used for the time modulation of the electron capture decay of hydrogen like ions with the Gamow-Teller transition $1^+\to 0^+$. The proposed mechanism offers a time oscillating decay with the frequency up to 0.1 Hz. The experiment to observe the modulation is proposed for ions stored in a Penning trap. An attempt to understand the GSI anomaly with multiple photon transitions is made.Comment: 5 pages, REVTeX. Added text and a reference