Study on steady-state thermal conduction with singularities in multi-material composites

Increasing demand in material and mechanical properties has led to production of complex composite structures. The composite structures, made of different materials, possess a variety of properties derived from each material. This has brought challenges in both analytical and numerical studies in thermal conduction which is of significant importance for thermoelastic problems. Therefore, a unified and effective approach would be desirable. The present study makes a first attempt to determining the analytical symplectic eigen solution for steady-state thermal conduction problem of multi-material crack. Based on the obtained symplectic eigen solution (including higher order expanding eigen solution terms), a new symplectic analytical singular element (SASE) for numerical modeling is constructed. It is concluded that composite structures composed of multi-material with complex geometric shapes can be modeled by the developed method, and the generalized flux intensity factors (GFIFs) can be solved accurately and efficiently

A novel size independent symplectic analytical singular element for inclined crack terminating at bimaterial interface

Cracks often exist in composite structures, especially at the interface of two different materials. These cracks can significantly affect the load bearing capacity of the structure and lead to premature failure of the structure. In this paper, a novel element for modeling the singular stress state around the inclined interface crack which terminates at the interface is developed. This new singular element is derived based on the explicit form of the high order eigen solution which is, for the first time, determined by using a symplectic approach. The developed singular element is then applied in finite element analysis and the stress intensity factors (SIFs) for a number of crack configurations are derived. It has been concluded that composites with complex geometric configurations of inclined interface cracks can be accurately simulated by the developed method, according to comparison of the results against benchmarks. It has been found that the stiffness matrix of the proposed singular element is independent of the element size and the SIFs of the crack can be solved directly without any post-processing

Plasminogen activator levels are influenced by location and varicosity in greater saphenous vein

AbstractPurpose: The plasminogen system, which includes tissue type plasminogen activator (tPA), urokinase type plasminogen activator (uPA), and their main inhibitor, plasminogen activator inhibitor type 1 (PAI-1), plays a major role in both fibrinolysis and tissue remodeling. This study compares the levels of tPA, uPA, and PAI-1 at the groin and ankle in normal and varicose greater saphenous vein (GSV).Methods: GSV was collected from patients undergoing varicose vein (VV) removal and from normal vein (NV) from arterial bypass procedures. Portions of the GSV at the groin and the ankle were minced and placed in serum-free media for 48 hours. Assays of the supernatants were obtained for tPA, uPA, and PAI-1 protein by enzyme-linked immunosorbent assay. Cyclohexamide and actinomycin D were also added to the media of the VV tissue explant supernatants to inhibit protein and RNA synthesis, respectively.Results: Levels of tPA were significantly higher at the groin (11 ± 2) than the ankle (5 ± 1) in the VV ( p < 0.005), and this trend was also seen in the NV (groin 10 ± 2 and ankle 7 ± 3). Levels of uPA were significantly higher in the groin VV (14 ± 4.3) than in NV (3.0 ± 0.8, p < 0.05). This difference, although not statistically significant, applied to the ankle as well (VV 14.5 ± 6.3 and NV 5.3 ± 2.7). No significant difference was seen between NV and VV for PAI-1 (NV, groin 155 ± 73 and ankle 113 ± 53, VV, groin 161 ± 20 and ankle 142 ± 38) or tPA. Inhibitor studies revealed no significant difference among control, cyclohexamide, and actinomycin D supernatants for tPA, suggesting release of protein rather than active synthesis. In contrast, inhibitor supernatants were significantly lower for uPA and PAI-1 than control supernatants ( p < 0.05), suggesting that uPA and PAI-1 were actively synthesized.Conclusions: In the tissue explant supernatant model uPA and PAI-1 are actively synthesized, but tPA is not. Levels of PAI-1 were comparable in all four groups. Levels of uPA in the varicose GSV were higher than in NV, suggesting a role for uPA in the pathologic makeup of VV. Levels of tPA were higher at the groin versus the ankle position, potentially explaining the previously described increased fibrinolytic activity seen at the groin. (J Vasc Surg 1996;24:719-24.

Electron Electric Dipole Moment from Lepton Flavor Violation

The general Minimal Supersymmetric Standard Model introduces new sources for Lepton Flavor Violation (LFV) as well as CP-violation. In this paper, we show that when both sources are present, the electric dipole moment of the electron, $d_e$, receives a contribution from the phase of the trilinear $A$-term of staus, $\phi_{A_\tau}$. For $\phi_{A_\tau}=\pi/2$, the value of $d_e$, depending on the ratios of the LFV mass elements, can range between zero and three orders of magnitude above the present bound. We show that the present bound on $d_e$ rules out a large portion of the CP-violating and the LFV parameter space which is consistent with the bounds on the LFV rare decays. We show that studying the correlation between $d_e$ and the P-odd asymmetry in $\tau \to e\gamma$ helps us to derive a more conclusive bound on $\phi_{A_\tau}$ We also discuss the possibility of cancelation among the contributions of different CP-violating phases to $d_e$.Comment: 35 pages, 9 figure

Neutrino hierarchy from CP-blind observables with high density magnetized detectors

High density magnetized detectors are well suited to exploit the outstanding purity and intensities of novel neutrino sources like Neutrino Factories and Beta Beams. They can also provide independent measurements of leptonic mixing parameters through the observation of atmospheric muon-neutrinos. In this paper, we discuss the combination of these observables from a multi-kton iron detector and a high energy Beta Beam; in particular, we demonstrate that even with moderate detector granularities the neutrino mass hierarchy can be determined for $\theta_{13}$ values greater than 4$^\circ$.Comment: 16 pages, 7 figures. Added a new section discussing systematic errors (sec 5.2); sec.5.1 and 4 have been extended. Version to appear in EPJ

Tomonaga-Luttinger parameters for quantum wires

The low-energy properties of a homogeneous one-dimensional electron system are completely specified by two Tomonaga-Luttinger parameters $K_{\rho}$ and $v_{\sigma}$. In this paper we discuss microscopic estimates of the values of these parameters in semiconductor quantum wires that exploit their relationship to thermodynamic properties. Motivated by the recognized similarity between correlations in the ground state of a one-dimensional electron liquid and correlations in a Wigner crystal, we evaluate these thermodynamic quantities in a self-consistent Hartree-Fock approximation. According to our calculations, the Hartree-Fock approximation ground state is a Wigner crystal at all electron densities and has antiferromagnetic order that gradually evolves from spin-density-wave to localized in character as the density is lowered. Our results for $K_{\rho}$ are in good agreement with weak-coupling perturbative estimates $K_{\rho}^{pert}$ at high densities, but deviate strongly at low densities, especially when the electron-electron interaction is screened at long distances. $K_{\rho}^{pert}\sim n^{1/2}$ vanishes at small carrier density $n$ whereas we conjecture that $K_{\rho}\to 1/2$ when $n\to 0$, implying that $K_{\rho}$ should pass through a minimum at an intermediate density. Observation of such a non-monotonic dependence on particle density would allow to measure the range of the microscopic interaction. In the spin sector we find that the spin velocity decreases with increasing interaction strength or decreasing $n$. Strong correlation effects make it difficult to obtain fully consistent estimates of $v_{\sigma}$ from Hartree-Fock calculations. We conjecture that v_{\sigma}/\vf\propto n/V_0 in the limit $n\to 0$ where $V_0$ is the interaction strength.Comment: RevTeX, 23 pages, 8 figures include

Search for Third Generation Vector Leptoquarks in p anti-p Collisions at sqrt(s) = 1.96 TeV

We describe a search for a third generation vector leptoquark (VLQ3) that decays to a b quark and tau lepton using the CDF II detector and 322 pb^(-1) of integrated luminosity from the Fermilab Tevatron. Vector leptoquarks have been proposed in many extensions of the standard model (SM). Observing a number of events in agreement with SM expectations, assuming Yang-Mills (minimal) couplings, we obtain the most stringent upper limit on the VLQ3 pair production cross section of 344 fb (493 fb) and lower limit on the VLQ3 mass of 317 GeV/c^2 (251 GeV/c^2) at 95% C.L.Comment: 7 pages, 2 figures, submitted to PR

Signal of New Physics and Chemical Composition of Matter in Core Crossing Neutrinos

We consider non-standard matter effect in flavor conversion of neutrinos crossing the core of the Earth. We show that oscillation of core crossing neutrinos with E \gsim 0.5 GeV can be well described by a first order perturbation theory. We show that due to non-standard matter effect varying chemical composition in the Earth can modify the neutrino flavor conversion by 100%. Effects of CP violating phases in non-standard Neutral Current interactions are emphasized in particular.Comment: 10 pages, 4 figure