MAT-759: PARTICLE SIZE ANALYSIS AS A MEANS TO BETTER UNDERSTAND THE INFLUENCE OF FLY ASH VARIABILITY IN CONCRETE

Fly ash is generated from thermal power stations as an industrial by-product of coal combustion materials. Its particles are generally glassy, spherical in shape, and typically range in size from 0.5-300 µm. Coal fly ash is widely used as a partial cementitious material in concrete, which not only offers economic and environmental benefits but also improves concrete performance. However, variability of the physical description and chemical composition of fly ash has been considered to be a major barrier to its increased use in cement and concrete. In this study the variability and properties of fly ash are characterized with an emphasis on particle size analysis as a means for fly ash producers to better understand material properties in relation to the process of production, classification, and potential modes of utilization. Fly ash samples were collected from different coal-fired power plants from certain Indian and Canadian sources. The particle size analysis results using Laser Diffraction Technique showed a wide variation between the particle size distributions of the studied sources. However, no correlation between the varied size distributions and chemical compositions of fly ash samples was found. Laboratory experiments on the selected fly ash samples are being undertaken to correlate fly ash characteristics and their effects on the performance of concrete mixtures with cementitious replacement level up to 50%

Proinflammatory Cytokines and Leptin Are Increased in Serum of Prepubertal Obese Children

It has not yet been shown in prepubertal children how cytokines, leptin, and body mass, as well as parameters of obesity are interrelated. The aim of this study was to explore the relation between circulating levels of some cytokines with leptin and body mass index. A case control study was carried out in obese children of both sexes. An obese group was carried out with 63 school prepubertal children and a control group comprised the same number of nonobese children paired by age and by sex. Mean serum leptin concentration was significantly higher in the obese children at 19.9 ± 7.4 ng/mL, than the control group (7.9 ± 5.1 ng/mL). Serum IL-1β, IL-6, and TNF-α levels were also significantly higher in the obese group than controls (33.0 ± 8.9, 45.2 ± 11.8, and 9.2 ± 2.3 pg/mL, versus 3.6 ± 1.0, 13.1 ± 3.9, and 3.9 ± 1.0 pg/mL, resp). In controversy, serum IL-2 level was diminished in the obese group as 0.4 ± 0.1 versus 0.9 ± 0.1 U/L. Obesity may be a low-grade systemic inflammatory disease. Obese prepubertal children have elevated serum levels of IL-1β, IL-6, and TNF-α which are known as markers of inflammation

Characterization of an embedded RF-MEMS switch

An RF-MEMS capacitive switch for mm-wave integrated circuits, embedded in the BEOL of 0.25μm BiCMOS process, has been characterized. First, a mechanical model based on Finite-Element-Method (FEM) was developed by taking the residual stress of the thin film membrane into account. The pull-in voltage and the capacitance values obtained with the mechanical model agree very well with the measured values. Moreover, S-parameters were extracted using Electromagnetic (EM) solver. The data observed in this way also agree well with the experimental ones measured up to 110GHz. The developed RF model was applied to a transmit/receive (T/R) antenna switch design. The results proved the feasibility of using the FEM model in circuit simulations for the development of RF-MEMS switch embedded, single-chip multi-band RF ICs

Silicon-Organic Hybrid (SOH) Mach-Zehnder Modulators for 100 Gbit/s On-Off Keying

Electro-optic modulators for high-speed on-off keying (OOK) are key components of short- and mediumreach interconnects in data-center networks. Besides small footprint and cost-efficient large-scale production, small drive voltages and ultra-low power consumption are of paramount importance for such devices. Here we demonstrate that the concept of silicon-organic hybrid (SOH) integration is perfectly suited for meeting these challenges. The approach combines the unique processing advantages of large-scale silicon photonics with unrivalled electro-optic (EO) coefficients obtained by molecular engineering of organic materials. In our proof-of-concept experiments, we demonstrate generation and transmission of OOK signals with line rates of up to 100 Gbit/s using a 1.1 mm-long SOH Mach-Zehnder modulator (MZM) which features a {\pi}-voltage of only 0.9 V. This experiment represents not only the first demonstration of 100 Gbit/s OOK on the silicon photonic platform, but also leads to the lowest drive voltage and energy consumption ever demonstrated at this data rate for a semiconductor-based device. We support our experimental results by a theoretical analysis and show that the nonlinear transfer characteristic of the MZM can be exploited to overcome bandwidth limitations of the modulator and of the electric driver circuitry. The devices are fabricated in a commercial silicon photonics line and can hence be combined with the full portfolio of standard silicon photonic devices. We expect that high-speed power-efficient SOH modulators may have transformative impact on short-reach optical networks, enabling compact transceivers with unprecedented energy efficiency that will be at the heart of future Ethernet interfaces at Tbit/s data rates

Coke–pitch interactions during anode preparation

The information on the interactions between coke and pitch is of great value for the aluminum industry. This information can help choose the suitable coke and pitch pairs as well as the appropriate mixing parameters to be used during the production of anodes. In this study, the interaction mechanisms of pitch and coke at the mixing stage were studied by a sessile-drop test using two coal-tar pitches as the liquid and three petroleum cokes as the substrate. The results showed that the coke–pitch interactions are related to both pitch and coke chemical compositions. The contact angle of different coke–pitch systems decreased with increasing time and temperature. At high temperatures, decreasing the pitch viscosity facilitated the spreading of pitch and its penetration into the coke bed. The chemical behavior of petroleum cokes and coal tar pitches were studied using the FT-IR spectroscopy and XPS. The results showed that the wettability behavior of cokes by pitches depends on their physical properties as well as the presence of surface functional groups of coke and pitch which can form chemical bonds

Dynamics investigation on motorcycle chassis based on Finite Element (FE) modelling and updating

Motorcycles built from multiple materials such as steel and aluminium that formed a welded of beams to construct the chassis. The frame is designed by combining the part-by-part saddle, handlebar and wheel that are attached together. In this study, the identification of structural dynamics study for motorcycle chassis was conducted to identify modal properties such as natural frequencies and mode shapes. This could be achieved by using two different analysis approaches; Finite Element Analysis (FEA) and Experimental Modal Analysis (EMA). For FEA analysis, 3D modeling of the chassis frame is needed and modelled using CAD software. Normal mode analysis was run on modelled structure to determine modal properties after meshing type and properties of materials declared. Impact hammer testing using roving accelerometer method was conducted for EMA study and comparison of modal properties with FEA is carried out. Discrepancies that appeared after correlation among two approaches attempted to be reduced by performing model updating procedure and it was successfully reduced the average percentage of error to be less than 10%. The results show that the model updating was an effective technique for improving the discrepancy that may exist due to modelling issue and material properties prediction in FEA. This study clearly shows that model updating technique is an effective way of reducing the discrepancies between EMA and FEA

Short-time dynamics and magnetic critical behavior of two-dimensional random-bond Potts model

The critical behavior in the short-time dynamics for the random-bond Potts ferromagnet in two-dimensions is investigated by short-time dynamic Monte Carlo simulations. The numerical calculations show that this dynamic approach can be applied efficiently to study the scaling characteristic, which is used to estimate the critical exponents theta, beta/nu and z for the quenched disorered systems from the power-law behavior of the kth moments of magnetizations.Comment: 10 pages, 4 figures Soft Condensed Matte

Modelling the bronchial barrier in pulmonary drug delivery: A human bronchial epithelial cell line supplemented with human tracheal mucus.

The airway epithelium together with the mucus layer coating it forms a protective system that efficiently filters and removes potentially harmful particles contained in inhaled air. The same mechanism, however, serves to entrap particulate drug carriers, precluding their interaction with their target. The mucus barrier is often neglected in in vitro testing setups employed for the assessment of pulmonary drug delivery strategies. Therefore, our aim was to more accurately model the bronchial barrier, by developing an in vitro system comprising a tight epithelial cell layer which may be optionally supplemented with a layer of human tracheal mucus. To form the epithelium in vitro, we used the cystic fibrosis cell line CFBE41o-, which can be grown as monolayers on Transwell® supports, expressing tight junctions as well as relevant transport proteins. In contrast to the cell line Calu-3, however, CFBE41o- does not produce mucus. Therefore, native human mucus, obtained from tracheal tubes of patients undergoing elective surgery, was used as a supplement. The compatibility of CFBE41o- cells with the human mucus was addressed with the MTT assay, and confirmed by fluorescein diacetate/propidium iodide live/dead staining. Moreover, the CFBE41o- cells retained their epithelial barrier properties after being supplemented with mucus, as evidenced by the high trans-epithelial electrical resistance values (∼1000Ωcm(2)) together with a continued low level of paracellular transport of sodium fluorescein. Fluorescently-labeled chitosan-coated PLGA nanoparticles (NP, ∼168nm) were used as a model drug delivery system to evaluate the suitability of this in vitro model for studying mucus permeation and cell uptake. Comparing CFBE41o- cell monolayers with and without mucus, resp., showed that the NP uptake was dramatically reduced in the presence of mucus. This model may therefore be used as a tool to study potential mucus interactions of aerosolized drugs, and more specifically NP-based drug delivery systems designed to exert their effect in the bronchial region

Silicon-organic hybrid (SOH) modulators for intensity-modulation / direct-detection links with line rates of up to 120 Gbit/s

High-speed interconnects in data-center and campus-area networks crucially rely on efficient and technically simple transmission techniques that use intensity modulation and direct detection (IM/DD) to bridge distances of up to a few kilometers. This requires electro-optic modulators that combine low operation voltages with large modulation bandwidth and that can be operated at high symbol rates using integrated drive circuits. Here we explore the potential of silicon-organic hybrid (SOH) Mach-Zehnder modulators (MZM) for generating high-speed IM/DD signals at line rates of up to 120 Gbit/s. Using a SiGe BiCMOS signal-conditioning chip, we demonstrate that intensity-modulated duobinary (IDB) signaling allows to efficiently use the electrical bandwidth, thereby enabling line rates of up to 100 Gbit/s at bit error ratios (BER) of 8.5 x 10(-5). This is the highest data rate achieved so far using a silicon-based MZM in combination with a dedicated signal-conditioning integrated circuit (IC). We further show four-level pulse-amplitude modulation (PAM4) at lines rates of up to 120 Gbit/s (BER = 3.2 x 10(-3)) using a high-speed arbitrary-waveform generator and a 0.5 mm long MZM. This is the highest data rate hitherto achieved with a sub-millimeter MZM on the silicon photonic platform. (C) 2017 Optical Society of Americ

Ising model on 3D random lattices: A Monte Carlo study

We report single-cluster Monte Carlo simulations of the Ising model on three-dimensional Poissonian random lattices with up to 128,000 approx. 503 sites which are linked together according to the Voronoi/Delaunay prescription. For each lattice size quenched averages are performed over 96 realizations. By using reweighting techniques and finite-size scaling analyses we investigate the critical properties of the model in the close vicinity of the phase transition point. Our random lattice data provide strong evidence that, for the available system sizes, the resulting effective critical exponents are indistinguishable from recent high-precision estimates obtained in Monte Carlo studies of the Ising model and \phi^4 field theory on three-dimensional regular cubic lattices.Comment: 35 pages, LaTex, 8 tables, 8 postscript figure