Thermoplastic coating of carbon fibers

A continuous powder coating system was developed for coating carbon fiber with LaRC-TPI (Langley Research Center-Thermoplastic Polyimide), a high-temperature thermoplastic polymide invented by NASA-Langley. The coating line developed used a pneumatic fiber spreader to separate the individual fibers. The polymer was applied within a recirculating powder coating chamber then melted using a combination of direct electrical resistance and convective heating to make it adhere to the fiber tow. The tension and speed of the line were controlled with a dancer arm and an electrically driven fiber wind-up and wind-off. The effects of heating during the coating process on the flexibility of the prepreg produced were investigated. The uniformity with which the fiber tow could be coated with polymer also was examined. Composite specimens were fabricated from the prepreg and tested to determine optimum process conditions. The study showed that a very uniform and flexible prepeg with up to 50 percent by volume polymer could be produced with this powder coating system. The coating line minimized powder loss and produced prepeg in lengths of up to 300 m. The fiber spreading was found to have a major effect on the coating uniformity and flexibility. Though test results showed low composite tensile strengths, analysis of fracture surfaces under scanning electron microscope indicated that fiber/matrix adhesion was adequate

Microscopic features of moving traffic jams

Empirical and numerical microscopic features of moving traffic jams are presented. Based on a single vehicle data analysis, it is found that within wide moving jams, i.e., between the upstream and downstream jam fronts there is a complex microscopic spatiotemporal structure. This jam structure consists of alternations of regions in which traffic flow is interrupted and flow states of low speeds associated with "moving blanks" within the jam. Empirical features of the moving blanks are found. Based on microscopic models in the context of three-phase traffic theory, physical reasons for moving blanks emergence within wide moving jams are disclosed. Structure of moving jam fronts is studied based in microscopic traffic simulations. Non-linear effects associated with moving jam propagation are numerically investigated and compared with empirical results.Comment: 19 pages, 12 figure

Pengaruh Laju Pengadukan dalam Pembuatan Bioetanol dari Limbah Serabut Buah Sawit Menggunakan Saccharomyces Cerevisiae

The development of new and renewable energy resources of government's strategies to reduce CO2 emission from industry waste and declining for national dependence of oil fuel. One of alternative energy that use to substitute a fuel oil is bioethanol. Palm fruit fibre waste is the one of potential source because of the biggest feedstock in Indonesia and the less uses that waste well. Some of type process used to convert bioethanol from industry waste, such as fermentation. The purpose of this experiment is decide the effect of fermentation in bioethanol production from palm fruit fibre waste to get an optimum bioethanol product. This experiment had pretreatments like delignification with ash extract palm fruit bunch and purification with H2O2 3% that were used to remove lignin in palm fruit fibre waste compound to get a lot of cellulose compound. The fermentation that use in this experiment is Separate Hydrolysis Fermentation (SHF) which is hydrolysis and fermentation done separately. Hydrolysis process using H2SO4 2 M for convert cellulose become glucose then will be done by anaerob fermentation by Saccharomyces cerevisiae. The variation of agitation speed (100, 150, 200, and 250 rpm) while fermentation learned to get an optimum bioethanol percentage. The result of experiment showed that in agitation speed at 200 rpm while 96 hours can convert a bioethanol 5 % (v/v) 39,465 g/L

Fluid Flow In Porous Media: NMR Imaging And Numerical Simulation

We use nuclear magnetic resonance (NMR) imaging to obtain a three-dimensional image of the pore structure in a limestone core, 4.5 mm in diameter and 10 mm in length, with a resolution of 40 μm. This image is converted into boundary conditions for simulation of fluid flow through the rock using the lattice gas method. The computed permeability is several orders of magnitude lower than the laboratory measured permeability, most likely a result of the image resolution being too coarse to resolve the smaller pore throats, which are believed to be significant for flow in this sample.Saudi AramcoMassachusetts Institute of Technology. Borehole Acoustics and Logging ConsortiumMassachusetts Institute of Technology. Earth Resources Laboratory. Reservoir Delineation Consortiu

The Effect Of Image Resolution On Fluid Flow Simulations In Porous Media

Realistic simulations of flow in porous media are dependent upon having a three-dimensional, high resolution image of pore structure which is difficult to obtain. So, we ask the question, "How fine a resolution is necessary to adequately model flow in porous media?" To find the answer, we take a 7.5 p,m resolution image and coarsen it to five different resolutions. Lattice gas simulations are performed on each image. From the simulation results, we observe changes in permeability and velocity fields as the resolution is altered. The results show permeability varies by a factor of 5 over the resolution range. Flow paths change as the resolution is changed. We also find that the image processing has a large impact on the outcome of the simulations.Massachusetts Institute of Technology. Borehole Acoustics and Logging ConsortiumMassachusetts Institute of Technology. Earth Resources Laboratory. Reservoir Delineation Consortiu

Unconventional Oil and Gas Development: Evaluation of selected hydrocarbons in the ambient air of three basins in the United States by means of diffusive sampling measurements

The impact of emissions associated with the extraction of crude oil and natural gas upon air quality in the United States (US) is widely recognised to have an impact on climate change, human health and ground-level ozone formation. A number of measurement approaches are being applied to evaluate the environmental impact of the oil and gas (O&G) sector, including satellite, airborne and ground-based platforms. Measurement based studies, in particular those that estimate flux rates, are critical for the validation of emission inventories that often under-report actual emissions of methane and volatile organic compounds (VOC) from the O&G sector. On-going research projects in the US are investigating the consistency of emission rates from O&G emission sources associated with extraction, transmission and distribution activities. The leakage rates of methane, as related to production levels, in the US for O&G developments varies from less than 1% (e.g. Upper Green River Basin, Wyoming) to over 6% (Uintah Basin, Utah). European research and policy approaches can learn from efforts in the US that are improving the accuracy of reporting emissions from O&G sources, enhancing our understanding of air quality impacts, and reducing emissions through regulatory controls. The Joint Research Centre (JRC) of the European Commission performed a diffusive sampling project, with the collaboration of the University of Wyoming, in conjunction with the SONGNEX (Studying the Atmospheric Effects of Changing Energy Use in the US at the Nexus of Air Quality and Climate Change) project led by the US National Oceanic and Atmospheric Administration. The SONGNEX project is an airborne measurement campaign supported by a number of associated ground based studies. The applicability of the Pocket Diffusive (PoD) sampler, for measurement of VOC (C4-C10), heavy hydrocarbons and volatile polycyclic aromatic hydrocarbons (PAHs) in areas heavily influenced by O&G development, is evaluated. Three sampling surveys were performed to assess three basins (Upper Green River, Uintah and North Platte) characterised by different management regimes, meteorology and hydrocarbon products. This first extensive field deployment of the PoD sampler demonstrates the effectiveness of the sampler for time-integrated measurements of targeted pollutants over wide spatial areas. The ambient air at these basins reveal different compositional profiles of hydrocarbons (C4-C10). Analysis of aromatics supports a finding of relatively elevated levels in the Pinedale Anticline (Upper Green River). From an evaluation of the behaviour of alkanes, it is evident that there is a relatively high leakage rate in the Uintah Basin. Heavy hydrocarbons (C11-C22) and PAHs are measured at relatively low levels. Despite low concentrations, analysis of these compounds improves the accuracy of source identification. A comparison of ground based PoD data and airborne SONGNEX data showed good agreement for commonly reported VOCs. The utility of the PoD sampler for analysis of emission sources was enhanced with reporting of a wide range of compounds. Spatial Positive Matrix Factorization analysis showed the possibility of using PoD samplers for differentiating emission sources, characterizing different areas and estimating the relative contribution of different emission sources.JRC.C.5-Air and Climat

Aphasia Treatment over the Internet: A Randomized Placebo-Controlled Clinical Trial

We report results of a randomized placebo-controlled clinical trial evaluating an aphasia treatment provided over the internet. Thirty-two persons with aphasia were randomized to receive 6 weeks of practice with Oral Reading for Language in Aphasia (ORLA) (N=19) or a commercial computer game (N=13). Results indicated significant changes on WAB-R subtests (AQ, reading and writing) with web-based ORLA; changes were maintained for six weeks. There was no significant difference between ORLA versus the placebo computer program.  Findings support the feasibility and efficacy of providing ORLA over the internet. Reasons for improvements with the commercial computer program are discussed

Home Endotoxin Exposure and Wheeze in Infants: Correction for Bias Due to Exposure Measurement Error

Exposure to elevated levels of endotoxin in family-room dust was previously observed to be significantly associated with increased wheeze in the first year of life among a cohort of 404 children in the Boston, Massachusetts, metropolitan area. However, it is likely that family-room dust endotoxin was a surrogate for airborne endotoxin exposure. Therefore, a related substudy characterized the relationship between levels of airborne household endotoxin and the level of endotoxin present in house dust, in addition to identifying other significant predictors of airborne endotoxin in the home. We now reexamine the relationship between endotoxin exposure and wheeze under the assumption that the level of airborne endotoxin in the home is the exposure of interest and that the amount of endotoxin in household dust is a surrogate for this exposure. We applied a measurement error correction technique, using all available data to estimate the effect of endotoxin exposure in terms of airborne concentration and accounting for the measurement error induced by using house-dust endotoxin as a surrogate measure in the portion of the data in which airborne endotoxin could not be directly measured. After adjusting for confounding by lower respiratory infection status and race/ethnicity, endotoxin exposure was found to be significantly associated with a nearly 6-fold increase in prevalence of wheeze for a one interquartile range increase in airborne endotoxin (95% confidence interval, 1.2–26) among the 360 children in households with dust endotoxin levels between the 5th and 95th percentiles

Preemptive and reactive spending in U.S. House races

This paper examines the spending behavior of candidates for the U.S. House of Representatives. Particular attention is paid to the timing of receipts and expenditures over the complete 2-year election cycle. Incumbents raise and spend large amounts of money very early in the race, and this preemptive spending may have a great impact on the selection of challengers and therefore on electoral outcomes. In addition, a model of reactive spending is tested for the general election period. Incumbents' expenditures are a function of the underlying partisan division in the district, the strength of the challenge, and candidates' feelings of vulnerability. Incumbents are strategic actors who attempt to maximize their chances of reelection. Early in the term, they spend preemptively in an effort to influence the selection of their challengers. Later in the term, they spend in reaction to the strength of their challengers' campaign. The role of money in congressional campaigns is neither simple nor direct. More attention needs to be given to the strategic uses of money in the period leading up to the general election campaign as well as to the dynamics of receipts and expenditures over an entire election cycle.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45496/1/11109_2004_Article_BF00987590.pd