A Formaldehyde Exposure Assessment Tool for Occupants of FEMA Temporary Housing Units

The report outlines the methodology used to develop a web-based tool to assess the formaldehyde exposure of the occupants of Federal Emergency Management Administration (FEMA) temporary housing units (THUs) after Hurricanes Katrina and Rita in 2005. Linear regression models were built using available data to retrospectively estimate the indoor temperature and relative humidity, formaldehyde emission factors and concentration, and hence the formaldehyde exposures. The interactive web-tool allows the user to define the inputs to the model to evaluate formaldehyde exposures for different scenarios

Extracting Information from Adaptive Control Experiments

Optical control of chemical reactivity is achieved through the use of photonic reagents, that is, “shaped” ultrafast optical pulses created using a pulse shaper. It has been demonstrated in a number of molecular systems that these pulses can effectively guide the system into a desired final state. Effective pulses are often found through an experimental search involving thousands of individual measurements. An examination of the pulses tested in these experiments can reveal the pulse features responsible for control and also the underlying molecular dynamics. In this article we review attempts to extract information from optical control experiments using adaptive learning algorithms to search the available parameter space, and we discuss how these kinds of experiments can be used to achieve and understand multiphoton optical control.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91361/1/397_ftp.pd

Optical properties of metal nanoparticles with no center of inversion symmetry: observation of volume plasmons

We present theoretical and experimental studies of the optical response of L-shaped silver nanoparticles. The scattering spectrum exhibits several plasmon resonances that depend sensitively on the polarization of the incident electromagnetic field. The physical origin of the resonances is traced to different plasmon phenomena. In particular, a high energy band with unusual properties is interpreted in terms of volume plasmon oscillations arising from the asymmetry of a nanoparticle.Comment: 14 pages, 5 figures. Physical Review B, 2007, accepte

Clinical characteristics of mephedrone toxicity reported to the UK National Poisons Information Service

Objective To describe the patterns and clinical features of toxicity related to recreational use of mephedrone and other cathinones in the UK using data collected by the National Poisons Information Service (NPIS). Methods The number of accesses to TOXBASE, the NPIS online poisons information database, details of consecutive cases uploaded onto TOXBASE and the number and details of telephone enquiries made to the NPIS by health professionals in the UK were collected for the period March 2009 to February 2010. Results Over the year of study there were 2901 TOXBASE accesses and 188 telephone enquiries relating to cathinones, the majority relating to mephedrone (TOXBASE 1664, telephone 157), with a month-on-month increase in numbers. In 131 telephone enquiries concerning mephedrone, alone or in combination with alcohol, common clinical features reported included agitation or aggression (n=32, 24%, 95% CI 18% to 33%), tachycardia (n=29, 22%, 95% CI 16% to 30%), confusion or psychosis (n=18, 14%, 95% CI 9% to 21%), chest pain (n=17, 13%, 95% CI 8% to 20%), nausea (n=15, 11%, 95% CI 7% to 18%), palpitations (n=14, 11%, 95% CI 6% to 18%), peripheral vasoconstriction (n=10, 8%, 95% CI 4% to 14%) and headache (n=7, 5%, 95% CI 2% to 11%). Convulsions were reported in four cases (3%, 95% CI 1% to 8%). One exposed person died following cardiac arrest (1%, 95% CI 0% to 4%), although subsequent investigation suggested that mephedrone was not responsible. Conclusions Toxicity associated with recreational mephedrone use is increasingly common in the UK. Sympathomimetic adverse effects are common and severe effects are also reported. Structured data collected by the NPIS may be of use in identifying trends in poisoning and in establishing toxidromes for new drugs of abuse

Quantifying Robotic Swarm Coverage

In the field of swarm robotics, the design and implementation of spatial density control laws has received much attention, with less emphasis being placed on performance evaluation. This work fills that gap by introducing an error metric that provides a quantitative measure of coverage for use with any control scheme. The proposed error metric is continuously sensitive to changes in the swarm distribution, unlike commonly used discretization methods. We analyze the theoretical and computational properties of the error metric and propose two benchmarks to which error metric values can be compared. The first uses the realizable extrema of the error metric to compute the relative error of an observed swarm distribution. We also show that the error metric extrema can be used to help choose the swarm size and effective radius of each robot required to achieve a desired level of coverage. The second benchmark compares the observed distribution of error metric values to the probability density function of the error metric when robot positions are randomly sampled from the target distribution. We demonstrate the utility of this benchmark in assessing the performance of stochastic control algorithms. We prove that the error metric obeys a central limit theorem, develop a streamlined method for performing computations, and place the standard statistical tests used here on a firm theoretical footing. We provide rigorous theoretical development, computational methodologies, numerical examples, and MATLAB code for both benchmarks.Comment: To appear in Springer series Lecture Notes in Electrical Engineering (LNEE). This book contribution is an extension of our ICINCO 2018 conference paper arXiv:1806.02488. 27 pages, 8 figures, 2 table

Lattice-matched epitaxial GaInAsSb/GaSb thermophotovoltaic devices

The materials development of Ga{sub 1{minus}x}In{sub x}As{sub y}Sb{sub 1{minus}y} alloys for lattice-matched thermophotovoltaic (TPV) devices is reported. Epilayers with cutoff wavelength 2--2.4 {micro}m at room temperature and lattice-matched to GaSb substrates were grown by both low-pressure organometallic vapor phase epitaxy and molecular beam epitaxy. These layers exhibit high optical and structural quality. For demonstrating lattice-matched thermophotovoltaic devices, p- and n-type doping studies were performed. Several TPV device structures were investigated, with variations in the base/emitter thicknesses and the incorporation of a high bandgap GaSb or AlGaAsSb window layer. Significant improvement in the external quantum efficiency is observed for devices with an AlGaAsSb window layer compared to those without one

High Order Multistep Methods with Improved Phase-Lag Characteristics for the Integration of the Schr\"odinger Equation

In this work we introduce a new family of twelve-step linear multistep methods for the integration of the Schr\"odinger equation. The new methods are constructed by adopting a new methodology which improves the phase lag characteristics by vanishing both the phase lag function and its first derivatives at a specific frequency. This results in decreasing the sensitivity of the integration method on the estimated frequency of the problem. The efficiency of the new family of methods is proved via error analysis and numerical applications.Comment: 36 pages, 6 figure

Unified concepts for understanding and modelling turnover of dissolved organic matter from freshwaters to the ocean: the UniDOM model

The transport of dissolved organic matter (DOM) across the land-ocean-aquatic continuum (LOAC), from freshwater to the ocean, is an important yet poorly understood component of the global carbon budget. Exploring and quantifying this flux is a significant challenge given the complexities of DOM cycling across these contrasting environments. We developed a new model, UniDOM, that unifies concepts, state variables and parameterisations of DOM turnover across the LOAC. Terrigenous DOM is divided into two pools, T1 (strongly-UV-absorbing) and T2 (non- or weakly-UV-absorbing), that exhibit contrasting responses to microbial consumption, photooxidation and flocculation. Data are presented to show that these pools are amenable to routine measurement based on specific UV absorbance (SUVA). In addition, an autochtonous DOM pool is defined to account for aquatic DOM production. A novel aspect of UniDOM is that rates of photooxidation and microbial turnover are parameterised as an inverse function of DOM age. Model results, which indicate that ~5% of the DOM originating in streams may penetrate into the open ocean, are sensitive to this parameterisation, as well as rates assigned to turnover of freshly produced DOM. The predicted contribution of flocculation to DOM turnover is remarkably low, although a mechanistic representation of this process in UniDOM was considered unachievable because of the complexities involved. Our work highlights the need for ongoing research into the mechanistic understanding and rates of photooxidation, microbial consumption and flocculation of DOM across the different environments of the LOAC, along with the development of models based on unified concepts and parameterisations