169 research outputs found

    Literature Review and Comparative Analysis of Existing Certification and Training Programs Applicable to Clean Water Project Operations and Maintenance

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    Stormwater runoff that carries sediments and nutrients is a primary pollutant entering surface waters in the State of Vermont. Phosphorus pollution is driving cyanobacteria blooms in many of our lakes including Lake Champlain, Lake Carmi, and Lake Memphremagog, especially in the warmer months. Warmer weather patterns and an increased frequency of extreme storms are predicted with climate change. As such, there is critical need to take action on the land to minimize and treat stormwater runoff on-site. The State adopted a Clean Water Act in 2015, which was swiftly followed by a Total Maximum Daily Load (TMDL) for Lakes Champlain and Memphremagog, and that was preceded by a TMDL for Lake Carmi. Each TMDL has an associated implementation and/or tactical basin plan that defines actions to address phosphorus transport in these watershed drainage areas. Other watersheds of the state also have land use practices guided by tactical basin plans. Green infrastructure practices are commonly recommended to address phosphorus pollution. Green infrastructure practices are nature-based solutions that clean and minimize stormwater runoff on-site. They include rain gardens and other types of bioretention basins, permeable pavers, green roofs, bioswales, and infiltration basins, among a variety of other systems that mimic nature to infiltrate, store and/or treat stormwater runoff to reduce its volume and clean it before it enters surface waters. While green infrastructure practices and other nature-based stormwater management solutions have become more and more commonplace in the state since the 1990s, understanding and awareness of the need for maintenance of these systems has grown overtime. Some installations have lost capacity to sustain their stormwater treatment and mitigation capabilities as a result of insufficient maintenance. In fact, long-term performance of green infrastructure practices is distinctly related to successful long-term maintenance. Act 76, Vermont’s Clean Water Service Delivery Act of 2019 sets forth requirements for the creation of an operation and maintenance (O&M) program for non-regulatory clean water projects funded through Clean Water Service Providers (CWSPs). The program will be complex, replete with new funding mechanisms, new policy and procedural guidelines, and a community of practice comprised of a myriad of stakeholders. In addition, it will include comprehensive training on the contents of a new Operations and Maintenance Standards Manual that was developed in 2020 by Hoyle, Tanner and Associates. This manual standardizes operations and maintenance procedures across land use types – from agriculture to developed lands and natural resources. This manual was nearing completion as this literature review and comparative analysis was conducted. The Operations and Maintenance Standards defined in the manual will need to be implemented by a capable and qualified suite of professionals who understand the general designs, functions, and required maintenance needs and timing for a variety of types of green infrastructure practices over time. These individuals will require training and both the individuals and the State may benefit if they are required to become certified to carry out maintenance on green infrastructure installations, as formalizing the training may add a level of quality assurance and control over the maintenance practices implemented by the contractors. As the program and its methods are being developed, it is helpful to ask: how do we engender quality maintenance practices? This paper looks at one possible tool: a certification program

    Extrapolation of Galactic Dust Emission at 100 Microns to CMBR Frequencies Using FIRAS

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    We present predicted full-sky maps of submillimeter and microwave emission from the diffuse interstellar dust in the Galaxy. These maps are extrapolated from the 100 micron emission and 100/240 micron flux ratio maps that Schlegel, Finkbeiner, & Davis (1998; SFD98) generated from IRAS and COBE/DIRBE data. Results are presented for a number of physically plausible emissivity models. We find that no power law emissivity function fits the FIRAS data from 200 - 2100 GHz. In this paper we provide a formalism for a multi-component model for the dust emission. A two-component model with a mixture of silicate and carbon-dominated grains (motivated by Pollack et al., 1994}) provides a fit to an accuracy of about 15% to all the FIRAS data over the entire high-latitude sky. Small systematic differences are found between the atomic and molecular phases of the ISM. Our predictions for the thermal (vibrational) emission from Galactic dust at \nu < 3000 GHz are available for general use. These full-sky predictions can be made at the DIRBE resolution of 40' or at the higher resolution of 6.1 arcmin from the SFD98 DIRBE-corrected IRAS maps.Comment: 48 pages, AAS LaTeX, 6 figures, ApJ (accepted). Data described in the text, as well as 4 additional figures, are available at http://astro.berkeley.edu/dus

    Optimal discrete slicing

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    International audienceSlicing is the procedure necessary to prepare a shape for layered manufacturing. There are degrees of freedom in this process, such as the starting point of the slicing sequence and the thickness of each slice. The choice of these parameters influences the manufacturing process and its result: The number of slices significantly affects the time needed for manufacturing, while their thickness affects the error. Assuming a discrete setting, we measure the error as the number of voxels that are incorrectly assigned due to slicing. We provide an algorithm that generates, for a given set of available slice heights and a shape, a slicing that is provably optimal. By optimal, we mean that the algorithm generates sequences with minimal error for any possible number of slices. The algorithm is fast and flexible, that is, it can accommodate a user driven importance modulation of the error function and allows the interactive exploration of the desired quality/time tradeoff. We demonstrate the practical importance of our optimization on several three-dimensional-printed results

    Studi Efisiensi Sistem Prasedimentasi Dan Free Water Surface Wetland Dalam Menurunkan Kadar Nitrat, Fosfat, Kekeruhan, Zat Organik Dan Total Coli

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    Boezem Wonorejo saat ini telah dikembangkan menjadi tempat wisata yaitu Ekowisata Mangrove. Sampai saat ini pihak pengelola boezem masih kesulitan dalam penyediaan air bersihnya Sungai Jagir yang mengalir di sekitar wilayah Ekowisata tersebut merupakan sumber air permukaan yang berpotensi sebagai pemenuhan kebutuhan tersebut secara kuantitatif. Agar dapat terpenuhi secara kualitatif, maka Perlu dilakukan penelitian awal untuk mengetahui efisiensi penurunan kadar Nitrat, Fosfat, Zat Organik, Kekeruhan maupun Total Coli. Dalam penelitian ini akan digunakan rangkaian suatu sistem pengolahan Prasedimentasi dan Free Water Surface wetland skala laboratoium, Dengan variabel ukuran media pasir (16-32 mesh dan lolos 32 mesh) dan umur mangrove (3 bulan dan 6 bulan) yang akan di analisis di laboratorium Teknik Lingkungan ITS. Dari hasil analisis didapat removal maksimum untuk kekeruhan pada prasedimentasi 46,5%, sedangkan pada wetland yaitu pada media pasir mesh 16-32 dan mangrove 6 bulan yaitu 94,8%. Presentase maksimum removal nitrat pada prasedimentasi yaitu 17,8%, removal maksimum pada wetland dengan mangrove 6 bulan dan media pasir lolos 32 mesh yaitu 53,6%. Pada mangrove sendiri removal makismum terdapat pada umur 6 bulan dengan besar removal 36,5%. Removal maksimum fosfat terbesar pada prasedimentasi yaitu 64,3%, untuk Reaktor Wetland yaitu pada wetland dengan mangrove 6 bulan dan media pasir lolos mesh 32 sebesar 90,5%. Untuk . Mangrovenya sendiri mampu meremoval maksimum pada umur 6 bulan dengan besar 53,8%. Presentase removal maksimum zat organik pada prasedimentasi sebesar 35,7%, pada reaktor wetland sebesar 21,8% dengan ukuran media pasir mesh 16-32 dan umur mangrove 3 bulan

    Blood-sampling collection prior to surgery may have a significant influence upon biomarker concentrations measured

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    Abstract Background Biomarkers can be subtle tools to aid the diagnosis, prognosis and monitoring of therapy and disease progression. The validation of biomarkers is a cumbersome process involving many steps. Serum samples from lung cancer patients were collected in the framework of a larger study for evaluation of biomarkers for early detection of lung cancer. The analysis of biomarker levels measured revealed a noticeable difference in certain biomarker values that exhibited a dependence of the time point and setting of the sampling. Biomarker concentrations differed significantly if taken before or after the induction of anesthesia and if sampled via venipuncture or arterial catheter. Methods To investigate this observation, blood samples from 13 patients were drawn 1–2 days prior to surgery (T1), on the same day by venipuncture (T2) and after induction of anesthesia via arterial catheter (T3). The biomarkers Squamous Cell Carcinoma antigen (CanAG SCC EIA, Fujirebio Diagnostics, Malvern, USA), Carcinoembrionic Antigen (CEA), and CYFRA 21-1 (Roche Diagnostics GmbH, Mannheim, Germany) were analyzed. Results SCC showed a very strong effect in relation to the sampling time and procedure. While the first two points in time (T1; T2) were highly comparable (median fold-change: 0.84; p = 0.7354; correlation ρ = 0.883), patients showed a significant increase (median fold-change: 4.96; p = 0.0017; correlation ρ = -0.036) in concentration when comparing T1 with the sample time subsequent to anesthesia induction (T3). A much weaker increase was found for CYFRA 21-1 at T3 (median fold-change: 1.40; p = 0.0479). The concentration of CEA showed a very small, but systematic decrease (median fold-change: 0.72; p = 0.0039). Conclusions In this study we show the unexpectedly marked influence of blood withdrawal timing (before vs. after anesthesia) and procedure (venous versus arterial vessel puncture) has on the concentration of the protein biomarker SCC and to a less extent upon CYFRA21-1. The potential causes for these effects remain to be elucidated in subsequent studies, however these findings highlight the importance of a standardized, controlled blood collection protocol for biomarker detection

    Limited diversity in natal origins of immature anadromous fish during ocean residency

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    Author Posting. © The Authors, 2009. This is the author's version of the work. It is posted here by permission of NRC Research Press for personal use, not for redistribution. The definitive version was published in Canadian Journal of Fisheries and Aquatic Sciences. 67 (2010): 1699-1707, doi:10.1139/F10-086.Variable migration patterns can play a significant role in promoting diverse life history traits among populations. However, population and stage specific movement patterns are generally unknown yet crucial aspects of life history strategies in many highly migratory species. We used a natural tag approach using geochemical signatures in otoliths to identify natal origins of one-year-old anadromous American shad (Alosa sapidissima) during ocean residency. Otolith signatures of migrants were compared to a database of baseline signatures from 20 source populations throughout their spawning range. Samples were dominated by fish from only two rivers, while all other potential source populations were nearly or completely absent. These data support the hypothesis that American shad exhibit diverse migratory behaviors and immature individuals from populations throughout the native range do not all mix on northern summer feeding grounds. Rather, our results suggest populations of anadromous fish are distributed heterogeneously at sea in the first year of life and thus may encounter different ocean conditions at a critical early life history stage.This work was funded by National Science Foundation grants OCE-0215905 and OCE-0134998 to SRT and by a WHOI Ocean Life Institute grant to BDW

    BLAST05: Power Spectra of Bright Galactic Cirrus at Submillimeter Wavelengths

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    We report multi-wavelength power spectra of diffuse Galactic dust emission from BLAST observations at 250, 350, and 500 microns in Galactic Plane fields in Cygnus X and Aquila. These submillimeter power spectra statistically quantify the self-similar structure observable over a broad range of scales and can be used to assess the cirrus noise which limits the detection of faint point sources. The advent of submillimeter surveys with the Herschel Space Observatory makes the wavelength dependence a matter of interest. We show that the observed relative amplitudes of the power spectra can be related through a spectral energy distribution (SED). Fitting a simple modified black body to this SED, we find the dust temperature in Cygnus X to be 19.9 +/- 1.3 K and in the Aquila region 16.9 +/- 0.7 K. Our empirical estimates provide important new insight into the substantial cirrus noise that will be encountered in forthcoming observations.Comment: Submitted to the Astrophysical Journal. Maps and other data are available at http://blastexperiment.info

    3D stochastic bicontinuous microstructures: Generation, topology and elasticity

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    Motivated by recent experimental investigations of the mechanical behavior of nanoporous metal we explore an efficient and robust method for generating 3D representative volume elements (RVEs) with strikingly similar behavior. Our approach adopts Cahn's method of generating a Gaussian random field by taking a superposition of standing sinusoidal waves of fixed wavelength but random in direction and phase. In its theory part, our study describes closed-form expressions for how the solid volume fraction affects the binarization level, mean structure size, specific surface area, averages of mean and Gaussian curvature, and the scaled topological genus. Based on numerical studies we report on criteria for achieving representative realizations of the structure by proper choice of the number of waves and element size. We also show that periodic structures are readily created. We analyze the mechanical properties considering linear and infinitesimal elasticity and evaluate the residual anisotropy (which can be made small) and the effective values of the Young's modulus and Poisson's ratio. The numerical results are in excellent agreement with experimental findings for the variation of stiffness with solid fraction of nanoporous gold made by dealloying. We propose scaling relations that achieve naturally a perfect agreement with the numerical and experimental data. The scaling relation for the stiffness accounts for a percolation-to-cluster transition in the random field microstructure at a finite solid fraction. We propose that this transition is the origin of the previously reported anomalous compliance of nanoporous gold

    Observations of Arp 220 using Herschel-SPIRE: An Unprecedented View of the Molecular Gas in an Extreme Star Formation Environment

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    We present Herschel SPIRE-FTS observations of Arp~220, a nearby ULIRG. The FTS continuously covers 190 -- 670 microns, providing a good measurement of the continuum and detection of several molecular and atomic species. We detect luminous CO (J = 4-3 to 13-12) and water ladders with comparable total luminosity; very high-J HCN absorption; OH+, H2O+, and HF in absorption; and CI and NII. Modeling of the continuum yields warm dust, with T = 66 K, and an unusually large optical depth of ~5 at 100 microns. Non-LTE modeling of the CO shows two temperature components: cold molecular gas at T ~ 50 K and warm molecular gas at T ~1350 K. The mass of the warm gas is 10% of the cold gas, but dominates the luminosity of the CO ladder. The temperature of the warm gas is in excellent agreement with H2 rotational lines. At 1350 K, H2 dominates the cooling (~20 L_sun/M_sun) in the ISM compared to CO (~0.4 L_sun/M_sun). We found that only a non-ionizing source such as the mechanical energy from supernovae and stellar winds can excite the warm gas and satisfy the energy budget of ~20 L_sun/M_sun. We detect a massive molecular outflow in Arp 220 from the analysis of strong P-Cygni line profiles observed in OH+, H2O+, and H2O. The outflow has a mass > 10^{7} M_sun and is bound to the nuclei with velocity < 250 km/s. The large column densities observed for these molecular ions strongly favor the existence of an X-ray luminous AGN (10^{44} ergs/s) in Arp 220.Comment: Accepted in ApJ on September 1, 201

    Diverse protostellar evolutionary states in the young cluster AFGL961

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    We present arcsecond resolution mid-infrared and millimeter observations of the center of the young stellar cluster AFGL961 in the Rosette molecular cloud. Within 0.2 pc of each other, we find an early B star embedded in a dense core, a neighboring star of similar luminosity with no millimeter counterpart, a protostar that has cleared out a cavity in the circumcluster envelope, and two massive, dense cores with no infrared counterparts. An outflow emanates from one of these cores, indicating a deeply embedded protostar, but the other is starless, bound, and appears to be collapsing. The diversity of states implies either that protostellar evolution is faster in clusters than in isolation or that clusters form via quasi-static rather than dynamic collapse. The existence of a pre-stellar core at the cluster center shows that that some star formation continues after and in close proximity to massive, ionizing stars.Comment: 22 pages, 7 figures, accepted for publication in Ap
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