cuIBM -- A GPU-accelerated Immersed Boundary Method

A projection-based immersed boundary method is dominated by sparse linear algebra routines. Using the open-source Cusp library, we observe a speedup (with respect to a single CPU core) which reflects the constraints of a bandwidth-dominated problem on the GPU. Nevertheless, GPUs offer the capacity to solve large problems on commodity hardware. This work includes validation and a convergence study of the GPU-accelerated IBM, and various optimizations.Comment: Extended paper post-conference, presented at the 23rd International Conference on Parallel Computational Fluid Dynamics (http://www.parcfd.org), ParCFD 2011, Barcelona (unpublished

Self-tuning of threshold for a two-state system

A two-state system (TSS) under time-periodic perturbations (to be regarded as input signals) is studied in connection with self-tuning (ST) of threshold and stochastic resonance (SR). By ST, we observe the improvement of signal-to-noise ratio (SNR) in a weak noise region. Analytic approach to a tuning equation reveals that SNR improvement is possible also for a large noise region and this is demonstrated by Monte Carlo simulations of hopping processes in a TSS. ST and SR are discussed from a little more physical point of energy transfer (dissipation) rate, which behaves in a similar way as SNR. Finally ST is considered briefly for a double-well potential system (DWPS), which is closely related to the TSS

Bank seasoned equity offers: do voluntary and involuntary offers differ?

Recent research has shown that for industrial and utilities’ seasoned equity offers (SEOs) the offer price discount is informative and has significant price effects. We examine whether the offer price discount for SEOs made by undercapitalized banks is different from those made by banks that were already overcapitalized prior to issue announcement. The former are labeled "involuntary" issues, and the latter "voluntary." Voluntary issues are likely made by opportunistic managers at times when their stock is overvalued. Prior research has argued and provided evidence suggesting that for involuntary issues, such timing discretion may be limited. However, we find no significant differences in the issue-date discount, and in issue-date abnormal returns between the two types of issues. We find that trading volume increases dramatically at the offer date, stays at abnormally high levels over a 60-day post–issue period, and is accompanied by a positive abnormal return in the post-offer period for both types of issues.Bank stocks

Offer-price discount of bank seasoned equity offers: do voluntary and involuntary offers convey different information?

Seasoned equity offers made by undercapitalized banks (labeled involuntary offers) could be different from other seasoned equity offers because the issuer is presumably under regulatory duress to make up the shortfall in required capital. For this reason, involuntary offers may exhibit limited managerial opportunism. When a firm issues seasoned equity, investment bankers gather information about the issuer in the period between the registration of the offer and its issue date. The information gathered during the book-building process gets reflected in the offer price discount on the issue date. We find that the offer price discount appears to convey more information to investors on the issue date for the voluntary issuers. However, we find that both types of issues show signs of market timing, and that investors react negatively to both types of issuance announcements. Our results are robust to several checks.Bank stocks

Containerless processing of amorphous ceramics

The absence of gravity allows containerless processing of materials which could not otherwise be processed. High melting point, hard materials such as borides, nitrides, and refractory metals are usually brittle in their crystalline form. The absence of dislocations in amorphous materials frequently endows them with flexibility and toughness. Systematic studies of the properties of many amorphous materials have not been carried out. The requirements for their production is that they can be processed in a controlled way without container interaction. Containerless processing in microgravity could permit the control necessary to produce amorphous forms of hard materials

Modeling the Human Kinetic Adjustment Factor for Inhaled Volatile Organic Chemicals: Whole Population Approach versus Distinct Subpopulation Approach

The objective of this study was to evaluate the impact of whole- and sub-population-related variabilities on the determination of the human kinetic adjustment factor (HKAF) used in risk assessment of inhaled volatile organic chemicals (VOCs). Monte Carlo simulations were applied to a steady-state algorithm to generate population distributions for blood concentrations (CAss) and rates of metabolism (RAMs) for inhalation exposures to benzene (BZ) and 1,4-dioxane (1,4-D). The simulated population consisted of various proportions of adults, elderly, children, neonates and pregnant women as per the Canadian demography. Subgroup-specific input parameters were obtained from the literature and P3M software. Under the “whole population” approach, the HKAF was computed as the ratio of the entire population's upper percentile value (99th, 95th) of dose metrics to the median value in either the entire population or the adult population. Under the “distinct subpopulation” approach, the upper percentile values in each subpopulation were considered, and the greatest resulting HKAF was retained. CAss-based HKAFs that considered the Canadian demography varied between 1.2 (BZ) and 2.8 (1,4-D). The “distinct subpopulation” CAss-based HKAF varied between 1.6 (BZ) and 8.5 (1,4-D). RAM-based HKAFs always remained below 1.6. Overall, this study evaluated for the first time the impact of underlying assumptions with respect to the interindividual variability considered (whole population or each subpopulation taken separately) when determining the HKAF

Using generalized PowerFlux methods to estimate the parameters of periodic gravitational waves

We investigate methods to estimate the parameters of the gravitational-wave signal from a spinning neutron star using Fourier transformed segments of the strain response from an interferometric detector. Estimating the parameters from the power, we find generalizations of the PowerFlux method. Using simulated elliptically polarized signals injected into Gaussian noise, we apply the generalized methods to estimate the squared amplitudes of the plus and cross polarizations (and, in the most general case, the polarization angle), and test the relative detection efficiencies of the various methods.Comment: 8 pages, presented at Amalid7, Sydney, Australia (July 2007), fixed minor typos and clarified discussion to match published CQG version; updated reference

Pathways towards reverse logistics adoption in Indian educational institutes: a challenging factors analysis

Reverse logistics (RL) has been proven to have a positive effect on addressing the issue of effectively utilizing resources. India has a population of over one billion people with most of it dominated by youth. Developing RL strategies and exposing it to students will encourage them to find ways to manage the limited resources available in our country. This study is focused on identifying the challenges of RL implementation in education institutes in India and finding the inter-relationship among them. The most crucial barrier to RL implementation in educational institutes is also sought in the process. We initially review the RL practices in the Indian sub-continent to examine the challenges of effectively implementing RL. We then identify the challenges of RL based on literature and discussions with experts from the education industry. The experts selected for this study include administrators from schools and universities in Kerala, India (South India). A survey was conducted in two phases. The Fuzzy-DEMATEL technique was applied to determine the inter-relationship between the challenges and obtain the causal diagram. Initially, 45 challenges were identified. Based on responses from experts from phase one of the survey, it was narrowed down to 29 crucial challenges. A pairwise comparison among the challenges was then done by experts in the education field. Finally, on the application of Fuzzy-DEMATEL, a causal diagram was generated to indicate the extent of influence of the RL challenges. Our findings indicate that educational institutions are faced with lack of awareness about reverse logistic, lack of responsibilities about environment, resistance to change, lack of supplies on supplier end, lack of knowledge, and no proper outlet for disposal in managing RL operations in educational institutes. The challenges identified in our study is unique to the Indian sub-continent and provides a result based on the current scenario of RL implementation in Indian educational institutes. The findings from our study indicate a unique perspective of RL implementation challenges. We analyzed 29 challenges to obtain our findings. Furthermore, we use Fuzzy-DEMATEL as our analysis tool to facilitate finding results. We present this as the uniqueness of our study from the available literature

Kinetics of Decomposition of Nitramine Propellant by Differential Scanning Calorimetry

The paper describes an experimental procedure for the determination of overall kinetic parameters for the exothermic decomposition reaction of nitramine propellant. The kinetic parameters can be obtained through the use of differential thermal analysis (DTA), differential scanning calorimetry (DSC) or thermogravimetric analysis (TGA) methods. The procedure is applicable to reactions whose behaviour can be described by the Arrhenius equation and the general rate law. In the present work, DSC technique has been used for the evaluation of Arrehenius activation parameters and specific rate constants for thermal decomposition of a typical nitramine propellant. The kinetic parameters were computed by Ozawa and Kissinger methods for comparison. The activation energy value obtained from the Ozawa method is refined by an iteration procedure using Doyle approximation for the Arrhenius temperature integral p(x)

Perceptions about quality of life in a school-based population of adolescents with menorrhagia: implications for adolescents with bleeding disorders

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73106/1/j.1365-2516.2008.01652.x.pd