742 research outputs found

    A Fully Differential CMOS Potentiostat

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    A CMOS potentiostat for chemical sensing in a noisy environment is presented. The potentiostat measures bidirectional electrochemical redox currents proportional to the concentration of a chemical down to pico-ampere range. The fully differential architecture with differential recording electrodes suppresses the common mode interference. A 200ÎŒm×200ÎŒm prototype was fabricated in a standard 0.35ÎŒm standard CMOS technology and yields a 70dB dynamic range. The in-channel analog-to-digital converter (ADC) performs 16-bit current-tofrequency quantization. The integrated potentiostat functionality is validated in electrical and electrochemical experiments

    Fracture toughness of ultra high performance concrete

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    In this study, fracture properties of Ultra-High Performance Concrete (UHPC), and High Performance Concrete (HPC) are presented. The average compressive strengths of UHPC and HPC used in the tests were 141 MPa, and 55 MPa respectively. Formulation and processing of the mixes and test specimens are also presented. Size effect and the influence of compressive strength of concrete on fracture parameters were investigated using test methods recommended by ACI Committee 446. The fracture properties investigated included crack opening displacement (COD), fracture energy GF, fracture toughness KIC, and bilinear approximation of the softening curve, for two different sizes of UHPC and HPC

    Parallel simulation of particle dynamics with application to micropolar peridynamic lattice modeling of reinforced concrete Structures

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    As the first goal of this thesis, we will explain a general purpose parallel particle dynamics code (pdQ2). We describe the re-architecting of pdQ (the MD/PD code that was developed in [Sakhavand 2011]) as pdQ2. pdQ2 is completely non-domain-specific in that user files are clearly separated from non-user files and no #ifdefs exist in the code. Thus, it operates as a particle simulation engine that is capable of executing any parallel particle dynamics model. As in the original pdQ, users can customize their own physical models without having to deal with complexities such as parallelization, but the ease of extensibility has been significantly improved. It is shown that pdQ2 is about four times as fast as pdQ using parallel supercomputers. In the second part of the thesis, we will model reinforced concrete structures based on peridynamic theory [Silling 1998]. We discard the continuum mechanics paradigm completely, and model reinforced concrete by introducing the micropolar peridynamic lattice model (MPLM)\u27. The MPLM models a structure as a close-packed particle lattice. In the MPLM, rather than viewing the structure as collection of truss or beam elements (as with traditional lattice models), the model is viewed as collection of particle masses (as with peridynamic models). The MPLM uses a finite number of equally-spaced interacting particles of finite mass. Thus, it does not need any ad hoc discretization and it is more straightforward to implement computationally. Also, the MPLM is conceptually simpler than both the lattice and peridynamic models [Gerstle et al. 2012]. After defining the MPLM, its application to reinforced concrete structures is investigated through several examples using pdQ2.\u2

    Surveying Techniques for Cultural Problems of Children Comic Strips Translation

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    AbstractComic strips, as we know today, have been around for over one hundred years. As a global phenomenon, comics enjoy a prominent place in translation studies. However, it should be pointed out that different cultures produce different comic strips. Furthermore, cultural adaptation includes processes such as domestication, internationalization, censorship and cultural jokes. In this paper, the researchers have tried to investigate cultural problems of children comic strips translations. To this end, we have selected one of the most popular comic books namely, “The adventures of Tin Tin” by Herge. It has been translated by different translators in recent years. Hence, the researchers analyzed the following questions: what are the problems of translating cultural notions from English to Persian in “the adventures of Tin Tin”? What adaptations have the translator made in translating cultural notions? What adaptations can be proposed to make the strips more understandable regarding cultural notions? The researchers have compared the original texts with their translations to see the problems and have endeavored to come up with some solutions to remove these problems

    Bio-based Renewable Additives for Anti-icing Applications (Phase I)

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    The performance and impacts of several bio-based anti-icers along with a traditional chloride-based anti-icer (salt brine) were evaluated. A statistical design of experiments (uniform design) was employed for developing anti-icing liquids consisting of cost-competitive chemicals such as bio-based compounds (e.g., sugar beet extract and dandelion extract), rock salt, sodium metasilicate, and sodium formate. The following experimentally obtained parameters were examined as a function of the formulation design: ice-melting capacity and ice penetration at 25°F (−3.9°C) and 15°F (−9.4°C), compressive strength of Portland cement mortar samples after 10 freezethaw/deicer cycles, corrosion rate of C1010 carbon steel after 24-hour immersion, and impact on asphalt binder’s stiffness. One viable formula (“best performer”) was tested for freezing point depression phase diagram (ASTM D1177-88) and the friction coefficient of asphalt pavement treated by this anti-icing formulation (vs. 23 wt.% NaCl) at a certain temperature near 25°F or 30°F after being applied at 30 gallons per lane mile (1 hour after simulated trafficking and plowing). Laboratory data shed light on the selection and formulation of innovative bio-based snow and ice control chemicals that can significantly reduce the costs of winter maintenance operations. This exploratory investigation contributes to more systematic study of optimizing “greener” anti-icers using renewable resources
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