759 research outputs found
An experimental documentation of a separated trailing-edge flow at a transonic Mach number
A detailed experiment on the separated flow field at a sharp trailing edge is described and documented. The separated flow is a result of sustained adverse pressure gradients. The experiment was conducted using an elongated airfoil-like model at a transonic Mach number and at a high Reynolds number of practical interest. Measurements made include surface pressures and detailed mean and turbulence flow quantities in the region just upstream of separation to downstream into the near-wake, following wake closure. The data obtained are presented mostly in tabular form. These data are of sufficient quality and detail to be useful as a test case for evaluating turbulence models and calculation methods
An experimental documentation of trailing-edge flows at high Reynolds number
Experiments documenting attached trailing-edge and near-wake flows at high Reynolds numbers are described. A long, airfoil-like model was tested at subsonic and low transonic Mach numbers, and both symmetrical and asymmetrical flows with pressure gradients upstream of the trailing edge were investigated. Model surface pressures and detailed mean and turbulence flow qualities were measured in the vicinity of the trailing edge and in the near-wake. The data obtained are of sufficient quality and detail to be useful as test cases in assessing turbulence models and calculation methods
Wire less Power Theft Monitoring Using GSM
Developing countries faces widespread theft of power from government owned power utilities. So the aim of this project is to display the power theft area of the distribution transformer and raise an alarm. Here for the practical purpose transformers, source energy meter, household load, energy meter are used for measuring real loads along with wired link.The power theft area of the distribution transformer at substation is obtained by calculating the real consuming power by the energy meter and the main power at the distribution transformer. That means the real consumption of all users must be equals to the total power delivered by the transformer. The difference must be analyzed by the controller by calculating both powers. If the difference is within 2 to 3% variation (transmission losses are concerned) the system raises no error otherwise it will generates error with an alarm and sends message along with transformer location information to the authority through GSM modem and displays in the corresponding substation along with alarm
The resistance of randomly grown trees
Copyright @ 2011 IOP Publishing Ltd. This is a preprint version of the published article which can be accessed from the link below.An electrical network with the structure of a random tree is considered: starting from a root vertex, in one iteration each leaf (a vertex with zero or one adjacent edges) of the tree is extended by either a single edge with probability p or two edges with probability 1 − p. With each edge having a resistance equal to 1 omega, the total resistance Rn between the root vertex and a busbar connecting all the vertices at the nth level is considered. A dynamical system is presented which approximates Rn, it is shown that the mean value (Rn) for this system approaches (1 + p)/(1 − p) as n → ∞, the distribution of Rn at large n is also examined. Additionally, a random sequence construction akin to a random Fibonacci sequence is used to approximate Rn; this sequence is shown to be related to the Legendre polynomials and its mean is shown to converge with |(Rn) − (1 + p)/(1 − p)| ∼ n−1/2.Engineering and Physical Sciences Research Council (EPSRC
A surgical study of serological markers such as C-reactive protein and interleukin 6 in response to postoperative infection in patients with open fractures in a tertiary care hospital
To study the response of C-reactive protein (CRP) and interleukin-6 (IL-6) to postoperative infection in patients with open fractures. Thirty patients with open fractures of extremities within 12 hours of injury were included in study. Blood samples were collected for Postoperative infection is a devastating complication of open fractures. The ideal investigation for early diagnosis of infection should be done before surgery and should be accurate, convenient to patient, cause minimal morbidity. Test such as CRP and IL-6 estimation is utilized in this study. CRP and IL 6 estimation on admission, second and fourth post-op day. All patients underwent surgery and reports evaluated. It was observed that CRP peak on post-op day 4 and IL 6 on postoperative day 2 in patients with infection before clinical evidence of infection. This prospective study includes 30 cases, followed up in ward for a week. Various factors regarding clinical presentation, findings of various investigations, operative treatment had been analyzed. The sensitivity of CRP in our study was 100%, and specificity was 42%. The persistent rise of CRP value seen within the infected group was statistically significant (p<0.05). The present clinical study of estimation of CRP and IL 6 to detect postoperative infection in patients after open fractures is an excellent diagnostic test for early detection and management of infection
Structural Properties and Catalytic Behaviour of CrOx/TiO2 Systems
The present investigation comprises of an attempt to investigate the titania supported chromia catalysts using X-ray diffraction measurements (XRD), evolved gas analysis (EGA), FT infrared spectroscopy (FTIR)
and FT-Raman spectroscopic techniques with catalytic evaluation by dehydrogenation of cyclohexane. Evolved Gas Analysis shows a modified decomposition pattern than that of bulk chromia and presence of
surface heterogeneity owing to the modified surface anchored chromia species formed as a result of interaction between chromia and titania. Above 773 K, Cr6+ is not stable over TiO2 surface and the reduction of the Cr6+ to intermediate chemical states take place. XRD investigations illustrate the significance of X-ray source in examining supported chromia catalysts to study the morphological modifications of the active phase when crystalline supports are employed. FT Raman spectra reveals that on calcining the sample at 573 K, for 2 hours, the chromia phase assumes a monomerically anchored molecular state. Longer calcination time (6 hours) at the same temperature, leads to the diffusion of in situ formed Cr3+ ions into the anatase lattice. On calcination at 973 K for 6 hours, amorphous chromia phase is no more stable on TiO2 support resulting in agglomeration leading to the germination of microcrystalline α–Cr2O3. Evaluation of catalytic performance of above catalysts by dehydrogenation of cyclohexane confirms the fact that diffusion of part of Cr3+ species into the bulk of anatase phase occurs under reaction conditions
Dimer and N\'eel order-parameter fluctuations in the spin-fluid phase of the s=1/2 spin chain with first and second neighbor couplings
The dynamical properties at T=0 of the one-dimensional (1D) s=1/2
nearest-neighbor (nn) XXZ model with an additional isotropic
next-nearest-neighbor (nnn) coupling are investigated by means of the recursion
method in combination with techniques of continued-fraction analysis. The focus
is on the dynamic structure factors S_{zz}(q,\omega) and S_{DD}(q,\omega),
which describe (for q=\pi) the fluctuations of the N\'eel and dimer order
parameters, respectively. We calculate (via weak-coupling continued-fraction
analysis) the dependence on the exchange constants of the infrared exponent,
the renormalized bandwidth of spinon excitations, and the spectral-weight
distribution in S_{zz}(\pi,\omega) and S_{DD}(\pi,\omega), all in the
spin-fluid phase, which is realized for planar anisotropy and sufficiently
weak nnn coupling. For some parameter values we find a discrete branch of
excitations above the spinon continuum. They contribute to S_{zz}(q,\omega) but
not to S_{DD}(q,\omega).Comment: RevTex file (7 pages), 8 figures (uuencoded ps file) available from
author
The extended Malkus-Robbins dynamo as a perturbed Lorenz system
Recent investigations of some self-exciting Faraday-disk homopolar dynamo ([1-4]) have yielded the classic Lorenz equations as a special limit when one of the principal bifurcation parameters is zero. In this paper we focus upon one of those models [3] and illustrate what happens to some of the lowest order unstable periodic orbits as this parameter is increased from zero
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