Bayesian Sequential Estimation of a Drift of Fractional Brownian Motion

Abstract

We solve explicitly a Bayesian sequential estimation problem for the drift parameter μ of a fractional Brownian motion under the assumptions that a prior density of μ is Gaussian and that a penalty function is quadratic or Dirac-delta. The optimal stopping time for this case is deterministic.     

Stability of the δ-TeO2 phase in the binary and ternary TeO2 glasses

The stability of δ-TeO₂ phase was studied in binary TeO₂–WO₃, TeO₂–CdO and ternary TeO₂–WO₃–CdO glasses. The samples were prepared by heating high purity powder mixtures of TeO₂, WO₃ and/or CdO to 800 °C in a platinum crucible with a closed lid, holding for 30 min and quenching in water bath. Differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used to characterize the thermal, phase and microstructural properties of the δ-TeO₂ phase. The addition of CdO into the tellurite glasses increased the stability range of the δ-TeO₂ phase up to higher temperature values and expanded the compositional δ-TeO₂ formation range. The formation of δ-TeO₂ phase in the binary systems was observed for samples containing 5–10 mol% WO₃ and 5–15 mol% CdO. However, for the ternary TeO₂–WO₃–CdO system the formation of δ-TeO₂ phase was determined in a wider compositional range.     

PMMA‐multigraft copolymers derived from linseed oil,soybean oil,and linoleic acid: Protein adsorption and bacterial adherence

Synthesis of Poly(methyl methacrylate), PMMA‐multigraft copolymers derived from linseed oil, soybean oil, and linoleic acid PMMA‐g‐polymeric oil/oily acid‐g‐poly(3‐hydroxy alkanoate) (PHA), and their protein adsorption and bacterial adherence have been described. Polymeric oil/oily acid peroxides [polymeric soybean oil peroxide (PSB), polymeric linseed oil peroxide (PLO), and polymeric linoleic acid peroxide (PLina)] initiated the copolymerization of MMA and unsaturated PHA‐soya to yield PMMA–PLO–PHA, PMMA–PSB–PHA, and PMMA–PLina–PHA multigraft copolymers. PMMA–PLina–PHA multigraft copolymers were completely soluble while PMMA–PSB–PHA and PMMA–PLO–PHA multigraft copolymers were partially crosslinked. Crosslinked parts of the PLO‐ and PSB‐multigraft copolymers were isolated by the sol gel analysis and characterized by swelling measurements in CHCl₃. Soluble part of the PLO‐ and PSB‐multigraft copolymers and completely soluble PLina‐multigraft copolymers were obtained and characterized by spectroscopic, thermal, gel permeation chromatography (GPC), and scanning electron microscopy (SEM) techniques. In the mechanical properties of the PHA–PLina–PMMA, the elongation at break is reduced up to ～ 9%, more or less preserving the high stress values at its break point (48%) when compared to PLina‐g‐PMMA. The solvent casting film surfaces were studied by means of adsorption of blood proteins and bacterial adhesion. Insertion of the PHA into the multigraft copolymers caused the dramatic increase in bacterial adhesion on the polymer surfaces. PHA insertion into the graft copolymers also increased the protein adsorption. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

An example to renovation–revitalization works in historical city centres: Kunduracılar Street/Trabzon-Turkey

Trabzon lies in the northeast of Turkey and its past goes as back as to the antique age. It is a multicultural city which hosted many civilizations throughout its history. Kundurac?lar Street is in the centre of the city of Trabzon and is a historical and important commercial axis and pedestrian-shopping centre. The buildings in this street contain a variety of building types which reflect the identity of the city. In a sense, these buildings are a mirror reflecting the multicultural structure that the city has had throughout its history. However, the cultural–historical entirety of this street has been under the effect of urban sprawl and visual pollution in recent years. By the time, the street loses its characteristics. This study is an attempt to solve such problems and aims at protecting the street through renovation–revitalization works, and to bring it back to the city and to the people of the city by improving the present conditions. This study is the first example of its kind in the region with its area along work of 1 km and with the wide participant model that it proposed. A renovation–revitalization work was carried out in the street under such titles as building façades, street ground, lighting, city furniture, green, etc., and the street was put in the use of the city and its people by improving its qualities. This study also planned and realized a new process for the city of Trabzon (a process of participation, sharing, and conscioussness).     

Seismic microzonation of the historic peninsula of İstanbul

In this study, the geological and geotechnical conditions of old Istanbul (Fatih and Eminönü provinces) were investigated in detail and a seismic microzonation study was undertaken for this historical peninsula, which is the site of many ancient structures. Dynamic site response, liquefaction potential and slope stability analyses were carried out, based on field and laboratory tests and earthquake time histories computed with respect to probabilities of exceedance of 10 and 40% in 50 years. The output data obtained from the analyses were evaluated by GIS techniques, and ground shaking, liquefaction susceptibility and landslide hazard maps were prepared.     

Synthesis and film properties of epoxy esters modified with amino resins from glycolysis products of postconsumer PET bottles

Glycolysis of waste polyethylene terephthalate (PET) flakes obtained from grinding postconsumer bottles was carried out at 225–250°C and molar ratios of PET/ethylene glycol were taken as 1/1, 1/1.5, 1/5, and 1/10. Reaction product was extracted by hot water for three times and water‐soluble crystallizable fraction and water‐insoluble fraction were obtained. These fractions were characterized by acid and hydroxyl value determinations, differential scanning calorimeter analysis, and ¹H‐NMR analysis. Glycolysis product was used for synthesis of PET‐based epoxy resin. This epoxy resin was used to prepare epoxy ester resins having 40% and 50% oil content. Epoxy ester resin having 40% oil content was modified with urea‐formaldehyde and melamine‐formaldehyde resins for synthesis of epoxy ester–amino resin. Physical and chemical film properties of epoxy ester and modified epoxy ester resins were investigated. All the epoxy ester and modified epoxy ester films were having excellent adhesion, water, and salt water resistance properties. Modification of PET‐based epoxy ester resins with amino resin has significantly improved hardness, impact resistance, and alkaline and acid resistance of resin films. As a result, PET oligomers obtained from glycolysis of postconsumer PET bottles are suitable for manufacturing of amino‐resin‐modified epoxy ester resins that have improved physical and chemical surface coating properties. POLYM. ENG. SCI., 55:2519–2525, 2015. © 2015 Society of Plastics Engineers     

Synthesis and characterization of a Zr‐containing silicate‐based epoxy‐functional polymer nanocomposite system

As a continuation of efforts to explore the potential of certain types of polymer nanocomposites to be successful candidates as dental restoration/adhesion materials, a Zr‐containing and organically modified silicate‐based material system with epoxy functionality was prepared by use of a sol–gel synthesis method, and UV light‐ and visible light (VL)‐curing processes. Comparative influences of the synthesis and processing parameters on the mechanical, thermal, and microstructural/nanostructural properties of the system were detailed. Zr‐containing species proved to more effectively catalyze the epoxy polymerization/crosslinking reactions than those containing Ti. Incorporation of Zr into the nanocomposite network led to significantly advanced mechanical properties. An elastic (Young's) modulus value of 23 MPa was achieved. The system with relatively high Zr content was successfully obtained, which also had higher thermal stability. Overall observations and results suggested that Zr content, and the UV light‐ or VL‐curing process could be capitalized on to modify the structure, and to improve the final properties of these material systems, which indicated a prospective opportunity for this material system to be utilized in dental restoration/adhesion applications. POLYM. ENG. SCI., 55:792–798, 2015. © 2014 Society of Plastics Engineers