610 research outputs found

    Clay/Biopolymer Composite and Electrorheological Properties

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    The combination of clays with polymers having different characteristics opens a way to new composite materials showing novel properties. Electrorheological (ER) fluids show phase transition from a liquid to a solid-like state between the electrodes of a rheometer due to the interactions of polarized particles. Composite systems comprising biodegradable chitosan (CS) and natural bentonite (BNT) are important in ER applications. In this study, BNT/CS composites were synthesized by the in situ method. The structure and morphology of the synthesized composites were characterized using X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), and scanning electron microscopy (SEM) techniques. Thermal stability was observed to increase with the presence of BNT clay. Conductivity of the composites was found the suitable range for ER measurements. According to ER results, BNT/CS composites were found to be sensitive to external electric field strength, exhibiting a typical shear thinning non-Newtonian viscoelastic behavior

    Dual Response of Materials under Electric and Magnetic Fields

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    The electrorheological (ER) effect is known as the change in the rheological behaviors of ER fluids under applied electric field E. When an E is imposed, ER fluids show phase transition from a liquid to a solid-like state due to the interactions of polarized particles. This solid-like behavior of particles is due to the increasing viscosity of suspensions. ER materials belong to a family of controllable fluids. ER fluids are dispersions of solid particles in a hydrophobic insulating dispersion medium. These solid particles play a very important role in the ER activity of dispersions. As the dispersed phase, diverse materials such as polymer blends, gels, biodegradable materials, clays, graphene oxide, hybrid nanocomposites, copolymers, ionic liquids, and conducting polymers have been proposed. In the magnetorheological fluids, this control is provided with magnetic field. Various magnetic particles such as carbonyl iron and iron oxides have been suggested as MR material. The combined effect of magnetic and electric field produces intensified rheological changes in the suspensions. This synergic effect is termed as electromagnetorheological effect (EMR). The EMR effect provides a new strategy to control the rheological properties of dispersions

    Capitalism, patriarchy and identity women and capitalist industrialisation in Turkey : textile workers in Manisa.

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    SIGLEAvailable from British Library Document Supply Centre-DSC:DX201009 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    Multiple Output Battery Charging Circuit for Bikers

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    Bikers want to charge their devices containing batteries (such as smart phones, bicycle headlight, head cameras), which they need in their daily lives, with the energy produced by their bicycles. A device capable of storing kinetic energy of bikers contributes to environment friendly electric power generation. This paper presents a multiple output battery charging circuit design for bikers. Proposed design consists of a dynamo capable of producing 12 V and it charges 2 × 4000 mAh storage batteries with a buck converter that produces an output voltage of 1.29 A 4.2 V. Li-ion batteries are the most suitable batteries for portable storage applications due to their compact size, light weight and long-life time features. 2 × 4000 mAh Li-ion batteries charge a 5 V 2000 mAh battery with a boost converter. Proposed method is simulated using MATLAB/Simulink. The simulation results are compared with the experimental results. The simulation and experimental results are in accordance with each other. A biker using the device suggested in the study will be able to ride an average of 2 hours a day and store the energy to fully charge the smart phone or bike headlight or head camera with 1 week of use

    Adjoint operator approach to shape design for internal incompressible flows

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    The problem of determining the profile of a channel or duct that provides the maximum static pressure rise is solved. Incompressible, laminar flow governed by the steady state Navier-Stokes equations is assumed. Recent advances in computational resources and algorithms have made it possible to solve the direct problem of determining such a flow through a body of known geometry. It is possible to obtain a set of adjoint equations, the solution to which permits the calculation of the direction and relative magnitude of change in the diffuser profile that leads to a higher pressure rise. The solution to the adjoint problem can be shown to represent an artificially constructed flow. This interpretation provides a means to construct numerical solutions to the adjoint equations that do not compromise the fully viscous nature of the problem. The algorithmic and computational aspects of solving the adjoint equations are addressed. The form of these set of equations is similar but not identical to the Navier-Stokes equations. In particular some issues related to boundary conditions and stability are discussed

    The effect of dietary inclusion of meat and bone meal on the performance of laying hens at old age

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    The effect of the inclusion of meat and bone meal (MBM) in the diet of old laying hens on their egg production and the quality of their eggs was investigated. Meat and bone meal containing a high concentration of ash and a low concentration of crude protein was included at levels of 2.0, 4.0 and 6.0% in the diets and fed for 20 weeks. Forced moulted 84-week old laying hens (Brown-Nick) were divided randomly into four treatment groups of 120 hens each. The inclusion of 2.0% MBM to the layer diet increased hen-day egg production significantly, whereas inclusion in excess of 2.0% MBM had no additional beneficial effect on egg production. However, the inclusion of dietary MBM at all three levels depressed egg weight. There were no significant effects of dietary treatments on egg weight, feed intake and feed conversion ratio of the hens. The specific gravity of the eggs from hens fed the control diet was significantly lower than from those receiving the diets containing 2.0 and 4.0% MBM. The Haugh Unit value of eggs in the 6.0% MBM treatment was significantly higher than the other treatments. There were no significant effects of MBM inclusion on yolk colour score, yolk height, eggshell thickness, eggshell weight and eggshell strength. However, MBM inclusion in a diet had a significant beneficial effect on eggshell quality. The eggshell ratios of the 2.0, 4.0 and 6.0% MBM treatments were significantly higher than in the control diet, while the cracked/broken egg ratio was significantly lower. In conclusion, inclusion of MBM containing a high ash and low crude protein content to conventional maize-soya bean diet improved egg production performance of laying hens. The dicalcium phosphate level in the diet could also be reduced without any adverse effects on egg production and egg quality. Key Words: Meat and bone meal, Egg production, Egg quality, Laying hens SA Jnl Animal Sci Vol.34(1) 2004: 31-3

    Verification of Possibilities of Prediction Financial Values Using Financial Models

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    Práce je zaměřena na ověření možností predikce finančních veličin pomocí finančních modelů. Tímto pojom myslíme ověření možnosti predikovat vývoj časových rád akciových indexů pomocí modelů ARIMA-GARCH a geometrické Brownova pohybu. Predikcí máme na mysli odhadnout budoucí vývoj směru pohybu cen. Práce je rozdělena na tři kapitoly, přičemž úvodní kapitola se zabývá základní charakteristikou finančních časových rád. Druhá kapitola se věnuje popisu finančních modelů a poslední kapitola konstrukci predikci.The work is focused on the verification of the possibility of prediction of financial variables using financial models. By this concept we mean to verify the possibility of predicting the development of stock indexes using ARIMA-GARCH models and geometric Brown motion. The prediction is to estimate the future development of price movements. The thesis is divided into three chapters, while the introductory chapter deals with the basic characteristics of financial time series. The second chapter deals with the description of financial models and the last chapter of the construction prediction.154 - Katedra financívýborn
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