489 research outputs found

    Bayesian Optimization for Probabilistic Programs

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    We present the first general purpose framework for marginal maximum a posteriori estimation of probabilistic program variables. By using a series of code transformations, the evidence of any probabilistic program, and therefore of any graphical model, can be optimized with respect to an arbitrary subset of its sampled variables. To carry out this optimization, we develop the first Bayesian optimization package to directly exploit the source code of its target, leading to innovations in problem-independent hyperpriors, unbounded optimization, and implicit constraint satisfaction; delivering significant performance improvements over prominent existing packages. We present applications of our method to a number of tasks including engineering design and parameter optimization

    9-[(2-Hy­droxy­benzyl­idene)amino]-11-(2-hy­droxy­phen­yl)-10,13-diphenyl-8-oxa-12-azoniatricyclo­[7.3.1.02,7]trideca-2(7),3,5-triene acetate ethanol disolvate

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    The title compound, C36H31N2O3 +,C2H3O2 −·2C2H5OH, the product of a domino condensation of dibenzyl ketone with salicylic aldehyde and ammonium acetate, crystallized as the ethanol disolvate. The cation of the salt comprises a fused tricyclic system containing three six-membered rings (piperidine, dihydro-2H-pyran and benzene). The piperidine ring has the usual chair conformation, while the dihydro­pyran ring adopts a slightly distorted sofa conformation. In the crystal, there are six (one intra- and five inter­molecular) independent hydrogen-bonding inter­actions: the inter­molecular hydrogen bonds link the cations and anions and ethanol solvent mol­ecules into ribbons along [001]. The ribbons are stacked along the a axis

    Flocculation of Reactive Blue 19 (RB19) using Alum and the Effects of Catalysts Addition

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    There are a variety of primary coagulants which can be used in a water treatment plant. One of the earliest, and still the most extensively used, is aluminum sulfate, also known as alum. Aluminum Sulfate (Alum) is one of the most commonly used flocculent in waste water treatment processes. Effectiveness of Alum in flocculation process is determined by many factors such as the effluents pH, flocculent dose as well as the use of catalyst to improve efficiency rate of flocculation. Hence special attention to these factors especially the use of catalyst has been brought about by this study. Experiments were carried out using Reactive Blue 19 Dye as the contaminant of waste water and two catalysts namely Calcium Hydroxide (CaOH2) and Poly Aluminum Chloride (PACl) were evaluated. The results obtained proved that indeed after addition of catalysts, removal efficiency rates of Alum can be increased up to 25% using Calcium Hydroxide and up to 35% using Poly Aluminum Chloride compared to Alum alone. The optimum conditions for this study were at pH 5.5 ~7.5, 300 mg/L of Alum 30seconds of rapid mixing time with 300 rpm , 30rpm of mixing rate for 5 minutes and 30 minutes of settling time. Moreover, Alum showed the highest performance under these conditions and using 50 mg/L PACl as catalyst with 98.52% of COD reduction and 90.60% of color reduction. In conclusion, Alum with the support of PACl as catalyst is an effective coagulant, which can reduce the level of COD and Dye Color in Reactive Blue 19 contaminated wastewater

    (2E,25E)-11,14,17,33,36,39,42-Hepta­oxa­penta­cyclo­[41.4.0.05,10.018,23.027,32]hepta­tetra­conta-1(43),2,5(10),6,8,18,20,22,25,27,29,31,44,46-tetra­decaene-4,24-dione

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    The title compound, C40H40O9, is a product of the double crotonic condensation of bis­(2-acetyl­phen­oxy)-3-oxapentane with bis­(2-formyl­phen­oxy)-3,6-dioxaoctane. The title macromolecule includes the 31-crown-7-ether skeletal unit and adopts a saddle-like conformation. The two ethyl­ene fragments have E configurations. The volume of the inter­nal cavity of the macrocycle is approximately 125 Å3. In the crystal, the mol­ecules are arranged at van der Waals distances

    The thermal properties of single walled carbon nanotubes

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    Carbon Nanotubes (CNTs) are extremely versatile and robust with their high electrical and thermal conductivity and mechanical strengths. They might be metallic and/or semiconducting depending on their chirality. This study focuses mainly on thermal properties of Single Walled Carbon Nanotubes (SWCNTs), which can be characterized by the shape of their edges, armchair, zigzag or chiral type. Thermal conductivity and heat flux autocorrelation function are obtained using Green- Kubo formalism. The formalism is a statistical and computational solution of phonon transport equation. The Nose Hoover thermostat and the Tersoff potential are incorporated in the simulator. Three open source codes have been used in this investigation. These include: Visual Molecular Dynamics (VMD), Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), and Dynamical matrix code. The numerical computation for the thermal conductivity is based on equilibrium molecular dynamics (EMD) technique. Ball State Beowulf Cluster and Wolfram Mathematica serves as a platform on which all results are obtained.Department of Physics and AstronomySWCNTs' structural geometries -- Theoretical methods for thermal conductivity calculation -- ResultsThesis (M.S.
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