Simultaneous evaluation of multiple PEMS using an engine dynamometer emissions test cell

Portable emission measurement systems (PEMS) are taking center stage as in-use testing programs are getting underway. EPA-mandated manufacturer-run in-use testing programs require a PEMS, and currently there is one commercially available and widely used, the SEMTECH-D built by Sensors, Inc. The SEMTECH-D was first unveiled in 2002, and numerous software and hardware upgrades have given way to the SEMTECHDS. The manufacturer claims this system is fully compatible with all new Code of Federal Regulations (CFR) including part 1065 subpart J (which addresses field testing and PEMS). Yet, while West Virginia University (WVU) was using the SEMTECH-D during the summer of 2005, problems were encountered that prompted further insight into its performance. A ten month study ensued to study SEMTECH-D\u27s behavior compared to an EPA certified engine test cell on the campus of WVU at Morgantown, WV. After multiple test days, exhaust configurations, and comparisons to both the heavy-duty engine dynamometer laboratory (compliant with CFR40 Part 86 Subpart N) at WVU, and another PEMS, the SEMTECH-D was found to consistently exhibit high discrepancies. Over a twenty minute Federal Test Procedure (FTP) transient test the total NOX mass emitted error was as high as 25%, while the CO2 total mass emitted error was as high as 15% compared to the engine dynamometer laboratory

Identity and belonging in social learning groups : the importance of distinguishing social, operational and knowledge-related identity congruence

Collaborative learning has much to offer but not all learners participate fully and peer groups can be exclusive. The paper examines how belonging or 'congruence' in learning groups is related to identities of gender, age, ethnicity and socio-economic status. A study of student experiences of collaborative learning on three different blended learning courses illustrated how learners negotiate identity congruence with peer groups to belong and engage. An analytical framework that distinguishes social, operational and knowledge-related identity congruence has emerged. Contrary to received wisdom, the social aspect appears least important for learner engagement while knowledge-related identity congruence is fundamental. Some of the consequences of identity incongruence, particularly concerning gender and maturity, are discussed and the paper points towards the pedagogies which might enable identities of group members to shift so that collaborative learning can flourish

The Parkes Galactic Meridian Survey (PGMS): observations and CMB polarization foreground analysis

We present observations and CMB foreground analysis of the Parkes Galactic Meridian Survey (PGMS), an investigation of the Galactic latitude behaviour of the polarized synchrotron emission at 2.3 GHz with the Parkes Radio Telescope. The survey consists of a 5-deg wide strip along the Galactic meridian l=254-deg extending from Galactic plane to South Galactic pole. We identify three zones distinguished by polarized emission properties: the disc, the halo, and a transition region connecting them. The halo section lies at latitudes |b| > 40-deg and has weak and smooth polarized emission mostly at large scale with steep angular power spectra of median slope $\beta_{\rm med} \sim -2.6$. The disc region covers the latitudes |b|<20-deg and has a brighter, more complex emission dominated by the small scales with flatter spectra of median slope $\beta_{\rm med} = -1.8$. The transition region has steep spectra as in the halo, but the emission increases toward the Galactic plane from halo to disc levels. The change of slope and emission structure at b \sim -20\degr is sudden, indicating a sharp disc-halo transition. The whole halo section is just one environment extended over 50-deg with very low emission which, once scaled to 70GHz, is equivalent to the CMB B-Mode emission for a tensor-to-scalar perturbation power ratio r_halo = 3.3 +/- 0.4 x 10^{-3}. Applying a conservative cleaning procedure, we estimate an r detection limit of $\delta r \sim 2\times 10^{-3}$ at 70~GHz (3-sigma C.L.) and, assuming a dust polariztion fraction <12%, $\delta r \sim 1\times 10^{-2}$ at 150~GHz. The 150-GHz limit matches the goals of planned sub-orbital experiments, which can therefore be conducted at this high frequency. The 70-GHz limit is close to the goal of proposed next generation space missions, which thus might not strictly require space-based platforms.Comment: 23 pages, 22 Figures. Accepted for publication on MNRAS. Some figures have been reduced in resolution. Replaced with the accepted version, 3 figures, more details on instrument performances, and map of polarization spectral index adde

Quantifying the response of the ORAC aerosol optical depth retrieval for MSG SEVIRI to aerosol model assumptions

We test the response of the Oxford-RAL Aerosol and Cloud (ORAC) retrieval algorithm for MSG SEVIRI to changes in the aerosol properties used in the dust aerosol model, using data from the Dust Outflow and Deposition to the Ocean (DODO) flight campaign in August 2006. We find that using the observed DODO free tropospheric aerosol size distribution and refractive index increases simulated top of the atmosphere radiance at 0.55 µm assuming a fixed erosol optical depth of 0.5 by 10–15 %, reaching a maximum difference at low solar zenith angles. We test the sensitivity of the retrieval to the vertical distribution f the aerosol and find that this is unimportant in determining simulated radiance at 0.55 µm. We also test the ability of the ORAC retrieval when used to produce the GlobAerosol dataset to correctly identify continental aerosol outflow from the African continent and we find that it poorly constrains aerosol speciation. We develop spatially and temporally resolved prior distributions of aerosols to inform the retrieval which incorporates five aerosol models: desert dust, maritime, biomass burning, urban and continental. We use a Saharan Dust Index and the GEOS-Chem chemistry transport model to describe dust and biomass burning aerosol outflow, and compare AOD using our speciation against the GlobAerosol retrieval during January and July 2006. We find AOD discrepancies of 0.2–1 over regions of intense biomass burning outflow, where AOD from our aerosol speciation and GlobAerosol speciation can differ by as much as 50 - 70 %

Traffic, Susceptibility, and Childhood Asthma

Results from studies of traffic and childhood asthma have been inconsistent, but there has been little systematic evaluation of susceptible subgroups. In this study, we examined the relationship of local traffic-related exposure and asthma and wheeze in southern California school children (5–7 years of age). Lifetime history of doctor-diagnosed asthma and prevalent asthma and wheeze were evaluated by questionnaire. Parental history of asthma and child’s history of allergic symptoms, sex, and early-life exposure (residence at the same home since 2 years of age) were examined as susceptibility factors. Residential exposure was assessed by proximity to a major road and by modeling exposure to local traffic-related pollutants. Residence within 75 m of a major road was associated with an increased risk of lifetime asthma [odds ratio (OR) = 1.29; 95% confidence interval (CI), 1.01–1.86], prevalent asthma (OR = 1.50; 95% CI, 1.16–1.95), and wheeze (OR = 1.40; 95% CI, 1.09–1.78). Susceptibility increased in long-term residents with no parental history of asthma for lifetime asthma (OR = 1.85; 95% CI, 1.11–3.09), prevalent asthma (OR = 2.46; 95% CI, 0.48–4.09), and recent wheeze (OR = 2.74; 95% CI, 1.71–4.39). The higher risk of asthma near a major road decreased to background rates at 150–200 m from the road. In children with a parental history of asthma and in children moving to the residence after 2 years of age, there was no increased risk associated with exposure. Effect of residential proximity to roadways was also larger in girls. A similar pattern of effects was observed with traffic-modeled exposure. These results indicate that residence near a major road is associated with asthma. The reason for larger effects in those with no parental history of asthma merits further investigation

Beam test results for the FiberGLAST instrument

The FiberGLAST scintillating fiber telescope is a large-area instrument concept for NASA\u27s GLAST program. The detector is designed for high-energy gamma-ray astronomy, and uses plastic scintillating fibers to combine a photon pair tracking telescope and a calorimeter into a single instrument. A small prototype detector has been tested with high energy photons at the Thomas Jefferson National Accelerator Facility. We report on the result of this beam test, including scintillating fiber performance, photon track reconstruction, angular resolution, and detector efficiency

Estimation of GRB detection by FiberGLAST

FiberGLAST is one of several instrument concepts being developed for possible inclusion as the primary Gamma-ray Large Area Space Telescope (GLAST) instrument. The predicted FiberGLAST effective area is more than 12,000 cm2 for energies between 30 MeV and 300 GeV, with a field of view that is essentially flat from 0°–80°. The detector will achieve a sensitivity more than 10 times that of EGRET. We present results of simulations that illustrate the sensitivity of FiberGLAST for the detection of gamma-ray bursts

Development and testing of a fiber/multianode photomultiplier system for use on FiberGLAST

A scintillating fiber detector is currently being studied for the NASA Gamma-Ray Large Area Space Telescope (GLAST) mission. This detector utilizes modules composed of a thin converter sheet followed by an x, y plane of scintillating fibers to examine the shower of particles created by high energy gamma-rays interacting in the converter material. The detector is composed of a tracker with 90 such modular planes and a calorimeter with 36 planes. The two major component of this detector are the scintillating fibers and their associated photodetectors. Here we present current status of development and test result of both of these. The Hamamatsu R5900-00-M64 multianode photomultiplier tube (MAPMT) is the baseline readout device. A characterization of this device has been performed including noise, cross- talk, gain variation, vibration, and thermal/vacuum test. A prototype fiber/MAPMT system has been tested at the Center for Advanced Microstructures and Devices at Louisiana State University with a photon beam and preliminary results are presented

Current status of 5α-reductase inhibitors in the management of lower urinary tract symptoms and BPH

Benign prostatic hyperplasia (BPH) is a progressive disease that is commonly associated with bothersome lower urinary tract symptoms (LUTS) and might result in complications, such as acute urinary retention and BPH-related surgery. Therefore, the goals of therapy for BPH are not only to improve LUTS in terms of symptoms and urinary flow, but also to identify those patients at a risk of unfavorable disease progression and to optimize their management. This article reviews the current status of therapy with 5 alpha-reductase inhibitors (5ARIs), namely fiasteride and dutasteride, for men with LUTS and BPH. Data from key randomized controlled trials (Oxford level 1b) on the use of 5ARIs are analyzed. The efficacy of 5ARIs either as monotherapy or in combination with alpha(1)-adrenoceptor antagonists in the management of LUTS and the impact of monotherapy and combined therapy on BPH progression are discussed. Further promises, including the withdrawal of the alpha-blocker from the combined medical treatment and the potential clinical implications from the use of 5ARIs for prostate cancer chemoprevention in patients receiving 5ARIs for symptomatic BPH are highlighted. Current evidence shows that 5ARIs are effective in treating LUTS and preventing disease progression and represent a recommended option in treatment guidelines for men who have moderate to severe LUTS and enlarged prostates