Degradation of Para-Phenylenediamine in Aqueous Solution by Photo-Fenton Oxidation Processes

In this research Photo-Fenton Oxidation of Para-Phenylenediamine (PPD) in aqueous solution by UV/Fenton’s reagent (Fe2+ and H2O2) was investigated. Experiments were conducted in a batch reactor, at pH 3.5 and at 25°C with a source of UV-C light. The effects of different reaction parameters such as initial PPD concentration, pH of the solution, ferrous concentration, Hydrogen peroxide concentration, on the oxidative degradation of PPD were measured. Final concentration of PPD and COD of the solution after treatment were determined to know degree of degradation of the compound. Iron source used for photo-Fenton’s oxidation were Ferrous Sulphate (FeSO4.7H2O).The optimum conditions established by Fenton’s oxidation without UV, were considered for this investigation. Only the maximum removal conditions were tried with the UV for reaction time of 3 hours. The results showed that under optimum experimental conditions, the pH 3.5, 50 mg/L H2O2, 3 mg/L Fe2+and UV reaction time of 3 hours, the initial concentration 10 mg/L of PPD was reduced by 71.20% with 65.89% COD removal. Likewise the removal efficiencies for PPD concentration of 20, 30, 40 and 50 mg/L keeping the same proportion of H2O2and Fe2+dosage (with ratios of PPD:Fe2+:H2O2::10:1:16.7) were investigated and the results showed, PPD removal were 65.10, 61.23, 58.34 and 54.26% and COD removal was 61, 54, 52 and 50.32% respectively. From the results obtained it can be concluded that Fenton’s reagent favours the lower concentration of Phenylenediamines and UV-C assisted photo-Fenton showed that the photo-Fenton process was very effective than the normal Fenton process.Keywords: Para-Phenylenediamine; COD; UV-C light; Fenton’s reagent; Oxidatio

Tomograms of Spinning Black Holes

The classical internal structure of spinning black holes is vastly different from that of static black holes. We consider spinning BTZ black holes, and probe their interior from the gauge theory. Utilizing the simplicity of the geometry and reverse engineering from the geodesics, we propose a thermal correlator construction which can be interpreted as arising from two entangled CFTs. By analytic continuation of these correlators, we can probe the Cauchy horizon. Correlators that capture the Cauchy horizon in our work have a structure closely related to those that capture the singularity in a non-rotating BTZ. As expected, the regions beyond the Cauchy horizon are not probed in this picture, protecting cosmic censorship.Comment: 41 pages, 7 figure

Holographic Coulomb Branch Flows with N=1 Supersymmetry

We obtain a large, new class of N=1 supersymmetric holographic flow backgrounds with U(1)^3 symmetry. These solutions correspond to flows toward the Coulomb branch of the non-trivial N=1 supersymmetric fixed point. The massless (complex) chiral fields are allowed to develop vevs that are independent of their two phase angles, and this corresponds to allowing the brane to spread with arbitrary, U(1)^2 invariant, radial distributions in each of these directions. Our solutions are "almost Calabi-Yau:" The metric is hermitian with respect to an integrable complex structure, but is not Kahler. The "modulus squared" of the holomorphic (3,0)-form is the volume form, and the complete solution is characterized by a function that must satisfy a single partial differential equation that is closely related to the Calabi-Yau condition. The deformation from a standard Calabi-Yau background is driven by a non-trivial, non-normalizable 3-form flux dual to a fermion mass that reduces the supersymmetry to N=1. This flux also induces dielectric polarization of the D3-branes into D5-branes.Comment: 22 pages; harvmac. Typos corrected;small improvements in presentatio

Comparison of the efficacy of sitagliptin with pioglitazone on dexamethasone-induced hepatic steatosis, dyslipidemia, and hyperglycemia in albino rats

Background: Sitagliptin is a dipeptidyl peptidase type 4 inhibitor. This study was done to assess the insulin-sensitizing effect of sitagliptin on Wistar albino rats by means of surrogate measures.Methods: There were four groups of six rats each. First group received dexamethasone alone in a dose of 8 mg/kg intraperitoneally for 6 days to induce metabolic changes and considered as dexamethasone control. Second group received sitagliptin 100 mg/kg orally 6 days before dexamethasone and 6 days during dexamethasone administration. Third group received pioglitazone 45 mg/kg orally 6 days before dexamethasone and 6 days during dexamethasone administration. Fourth group did not receive any medication and was considered as normal control. Fasting blood sugar, lipid profile, blood sugar 2 hrs after glucose load (postprandial blood sugar), liver weight, liver volume, and histopathological analysis were done.Results: The effects of sitagliptin were compared with that of pioglitazone. Dexamethasone caused hepatomegaly, dyslipidemia, and hyperglycemia. Both pioglitazone and sitagliptin significantly reduced hepatomegaly, dyslipidemia, and hyperglycemia (p<0.01). Reduction of blood sugar levels after glucose load was significant with pioglitazone in comparison to sitagliptin (p<0.01).Conclusions: Sitagliptin has comparable efficacy to pioglitazone in dexamethasone-induced hepatomegaly, dyslipidemia, and fasting hyperglycemia

Type IIB Holographic Superfluid Flows

We construct fully backreacted holographic superfluid flow solutions in a five-dimensional theory that arises as a consistent truncation of low energy type IIB string theory. We construct a black hole with scalar and vector hair in this theory, and study the phase diagram. As expected, the superfluid phase ceases to exist for high enough superfluid velocity, but we show that the phase transition between normal and superfluid phases is always second order. We also analyze the zero temperature limit of these solutions. Interestingly, we find evidence that the emergent IR conformal symmetry of the zero-temperature domain wall is broken at high enough velocity.Comment: v3: Published version. Figures 5 and 6 corrected. 24 pages, 7 figure

Symplectic potentials and resolved Ricci-flat ACG metrics

We pursue the symplectic description of toric Kahler manifolds. There exists a general local classification of metrics on toric Kahler manifolds equipped with Hamiltonian two-forms due to Apostolov, Calderbank and Gauduchon(ACG). We derive the symplectic potential for these metrics. Using a method due to Abreu, we relate the symplectic potential to the canonical potential written by Guillemin. This enables us to recover the moment polytope associated with metrics and we thus obtain global information about the metric. We illustrate these general considerations by focusing on six-dimensional Ricci flat metrics and obtain Ricci flat metrics associated with real cones over L^{pqr} and Y^{pq} manifolds. The metrics associated with cones over Y^{pq} manifolds turn out to be partially resolved with two blowup parameters taking special (non-zero)values. For a fixed Y^{pq} manifold, we find explicit metrics for several inequivalent blow-ups parametrised by a natural number k in the range 0<k<p. We also show that all known examples of resolved metrics such as the resolved conifold and the resolution of C^3/Z_3 also fit the ACG classification.Comment: LaTeX, 34 pages, 4 figures (v2)presentation improved, typos corrected and references added (v3)matches published versio

Cascading Quivers from Decaying D-branes

We use an argument analogous to that of Kachru, Pearson and Verlinde to argue that cascades in L^{a,b,c} quiver gauge theories always preserve the form of the quiver, and that all gauge groups drop at each step by the number M of fractional branes. In particular, we demonstrate that an NS5-brane that sweeps out the S^3 of the base of L^{a,b,c} destroys M D3-branes.Comment: 11 pages, 1 figure; v2: references adde

Can Quantum de Sitter Space Have Finite Entropy?

If one tries to view de Sitter as a true (as opposed to a meta-stable) vacuum, there is a tension between the finiteness of its entropy and the infinite-dimensionality of its Hilbert space. We invetsigate the viability of one proposal to reconcile this tension using $q$-deformation. After defining a differential geometry on the quantum de Sitter space, we try to constrain the value of the deformation parameter by imposing the condition that in the undeformed limit, we want the real form of the (inherently complex) quantum group to reduce to the usual SO(4,1) of de Sitter. We find that this forces $q$ to be a real number. Since it is known that quantum groups have finite-dimensional representations only for $q=$ root of unity, this suggests that standard $q$-deformations cannot give rise to finite dimensional Hilbert spaces, ruling out finite entropy for q-deformed de Sitter.Comment: 10 pages, v2: references added, v3: minor corrections, abstract and title made more in-line with the result, v4: published versio