Radiation crosslinked polyvinyl alcohol/polyvinyl pyrrolidone/acrylic acid hydrogels: swelling,crosslinking and dye adsorption study

Iranian Polymer Journal - Hydrogels were produced from mixtures of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), and acrylic acid (AAc) using γ-radiation at doses of 3, 7, and...     

Approximate methods in Bayesian point process spatial models

A range of point process models which are commonly used in spatial epidemiology applications for the increased incidence of disease are compared. The models considered vary from approximate methods to an exact method. The approximate methods include the Poisson process model and methods that are based on discretization of the study window. The exact method includes a marked point process model, i.e., the conditional logistic model. Apart from analyzing a real dataset (Lancashire larynx cancer data), a small simulation study is also carried out to examine the ability of these methods to recover known parameter values. The main results are as follows. In estimating the distance effect of larynx cancer incidences from the incinerator, the conditional logistic model and the binomial model for the discretized window perform relatively well. In explaining the spatial heterogeneity, the Poisson model (or the log Gaussian Cox process model) for the discretized window produces the best estimate.     

Transfer between pose and illumination training in face recognition.

The relationship between pose and illumination learning in face recognition was examined in a yes–no recognition paradigm. The authors assessed whether pose training can transfer to a new illumination or vice versa. Results show that an extensive level of pose training through a face–name association task was able to generalize to a new illumination (Experiments 1 and 3), but an equal level of illumination training failed to generalize to a new pose (Experiment 2). The transfer of pose training was likely to depend on a relatively extensive level of training because the same faces with reduced level of exposure (Experiment 4) were unable to reproduce the transfer effect. The findings suggest that generalization of pose training may be extended to different types of image variation, whereas generalization of illumination training may be confined within the trained type of variation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Long-Term Structural Health Monitoring of the San Ysidro Bridge

As part of the Lifecycle Innovative Financing Evaluation initiative, the San Ysidro Bridge along U.S. Route 550 will be monitored throughout a 10?year warranty period to determine changes in deflection, stiffness, and load-carrying capacity. This paper discusses an initial live-load test on the San Ysidro Bridge as well as a subsequent load test on a full-scale single lane test bridge. The two load tests in conjunction with finite element modeling were used to determine the load rating for both shear and moment of the San Ysidro Bridge. This load rating was then compared with the load rating using the distribution factors from the American Association of State Highway and Transportation Officials (AASHTO) Standard and Load and Resistance Factor Design Specifications. According to both AASHTO specifications, the interior girder shear controlled the load rating of the San Ysidro Bridge. Using the finite element modeling scheme of frame and shell elements the interior girder moment was found to control the design. This load rating will be used as a baseline for comparison with future load ratings throughout the warranty period.     

Bioreduction of Hexavalent Chromium in Flow-Through Quartz Sand Columns

Hexavalent chromium (Cr(VI)) contamination of soil and groundwater is a major environmental concern for some industrial sites and most of the U.S. Department of Energy sites. Cr(VI) is toxic and fairly mobile in groundwater. Bioreduction of Cr(VI) to less toxic and less mobile Cr(III) is considered to be a feasible option. Among the Cr(VI) reducing bacteria, Shewanella oneidensis MR-1 (MR-1) has been shown to be effective in metal reduction under anaerobic conditions. Data on bioreduction of Cr(VI) by MR-1 in a flow-through soil column that better approximates the subsurface condition are not available. The objective of this research project was to study the bioreduction of Cr(VI) by MR-1 in a continuous-flow quartz sand column system. MR-1 was found to be very effective in reducing Cr(VI) to Cr(III) for concentrations ranging from 0.055 mM (2.85?mg/L) to 0.006 mM (0.31?mg/L). The amount of Cr(VI) reduced prior to its breakthrough was found to be inversely proportional to its concentration in the feed due to increased inhibition of microbial activity and a residual reduction of 20–45% of Cr(VI) was observed even after its breakthrough.     

Performance study of a falling-film absorber with a film-inverting configuration

This paper describes the development of a novel film-inverting design concept for falling-film absorbers. The solid surface of the absorber is segmented so that both surfaces of the falling-film are alternatively cooled in a periodic manner. A conventional tubular absorber is modified by introducing film-guiding fins between tubes to produce a film-inverting arrangement. A maximum increase in vapour absorption rate of about 100% is obtained with the film-inverting design compared to the tubular absorber. The numerical simulation indicates that the vapour absorption rate can be increased by using a large number of film-inverting segments in the absorber.     

Single-Mixture Audio Source Separation by Subspace Decomposition of Hilbert Spectrum

A novel technique is developed to separate the audio sources from a single mixture. The method is based on decomposing the Hilbert spectrum (HS) of the mixed signal into independent source subspaces. Hilbert transform combined with empirical mode decomposition (EMD) constitutes HS, which is a fine-resolution time-frequency representation of a nonstationary signal. The EMD represents any time-domain signal as the sum of a finite set of oscillatory components called intrinsic mode functions (IMFs). After computing the spectral projections between the mixed signal and the individual IMF components, the projection vectors are used to derive a set of spectral independent bases by applying principal component analysis (PCA) and independent component analysis (ICA). A k-means clustering algorithm based on Kulback-Leibler divergence (KLd) is introduced to group the independent basis vectors into the number of component sources inside the mixture. The HS of the mixed signal is projected onto the space spanned by each group of basis vectors yielding the independent source subspaces. The time-domain source signals are reconstructed by applying the inverse transformation. Experimental results show that the proposed algorithm performs separation of speech and interfering sound from a single mixture     

Robust forecasting of mortality and fertility rates: A functional data approach

A new method is proposed for forecasting age-specific mortality and fertility rates observed over time. This approach allows for smooth functions of age, is robust for outlying years due to wars and epidemics, and provides a modelling framework that is easily adapted to allow for constraints and other information. Ideas from functional data analysis, nonparametric smoothing and robust statistics are combined to form a methodology that is widely applicable to any functional time series data observed discretely and possibly with error. The model is a generalization of the Lee-Carter (LC) model commonly used in mortality and fertility forecasting. The methodology is applied to French mortality data and Australian fertility data, and the forecasts obtained are shown to be superior to those from the LC method and several of its variants.     

Synthesis of high purity Tl1212 superconductor with ultrafine grains from coprecipitated Tl-free precursor route

In this study, high purity and fine-grained Tl1212 superconductor samples were successfully synthesized from Tl_0.8Bi_0.2Sr₂Ca_0.8Y_0.2Cu₂O₇ starting composition by a two-step solid-state reaction method using Tl-free precursor powder prepared from coprecipitation method. XRD pattern of the sample, which was sintered at 1,000 °C for 6 min essentially showed formation of high purity 1212 phase. The sample’s zero resistance critical temperature, T _{c zero} was 91 K and bulk critical current density, J _c measured at 40 K in zero magnetic field was 11.2 A/cm². SEM investigation on the sample revealed ultrafine homogeneous grains that are randomly orientated with grain sizes of approximately 0.5–1 μm. Resintering the sample did not affect its superconducting properties but induced clustering of grains as observed by SEM. It is suggested that the sample be used in specialized measurement techniques such as in ultrasonic studies where high purity and ultrafine-grained samples are required.