85 research outputs found

    “Blue” Hydrogen & Helium From Flare Gas Of The Bakken Formation Of The Williston Basin, North Dakota: A Novel Process

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    Is it possible to curtail flaring in the Williston basin while simultaneously sequestering carbon dioxide, harvesting economic quantities of natural gas liquids, helium and other valuable products? Utilizing a novel approach described here, diatomic hydrogen and elemental helium, as well as other products, can be profitably extracted from the gas streams produced from horizontal, hydraulically-fractured Middle Bakken Member wells, in the Devonian-Mississippian Bakken Formation of the Williston Basin, North Dakota, USA.However, there are two vastly different methods employed to extract these gasses. Hydrogen is harvested from the gas stream by physically reforming methane (CH4) through the application of one or another of two-stage processes: “Autothermal Reformation + Water Gas Shift (WGS) reaction”, known as ATR; or “Steam Methane Reforming”, SMR. Both yield H2, plus CO (carbon monoxide) in the first phase, and CO2 (carbon dioxide) after the second. Elemental diatomic hydrogen (H2) can be used in fuel cells to generate electricity or directly in certain internal combustion engines; primarily turbines, as primary fuel. The produced CO2 can be captured (CCUS: Carbon Capture, Utilization and Sequestration) and injected downhole for both reservoir energy enhancement and CO2 sequestration, or sold for industrial use because of its purity. Helium, on the other hand, is inert and therefore it is unnecessary to expend the amount of energy required to reformat methane to liberate hydrogen. There are several methods commercially available to economically extract 99.995% pure helium from gas streams where the helium concentration can be as low as 0.010%. The extraction of crude helium from natural gas requires three processing steps. The first step removes impurities through deamination, glycol absorption, nitrogen rejection, and desiccant adsorption, which remove CO2, H2O, N2, and H2S; a typical gas pre-treatment process. The second step removes high-molecular weight hydrocarbons (Natural Gas Liquids), if desired, while the third step is via cryogenics, which removes the final methane. The result is 75-90% pure helium. Final purification, before liquefaction, is accomplished via activated charcoal absorbers at liquid-nitrogen temperatures and high pressure, or pressure-swing adsorption (PSA) processes. Low-temperature adsorption can yield helium purities of 99.99 percent, while PSA processes recover helium at better than 99.9999 percent purity. However, with the advent of selective zeolite or organometallic membranes, the cryogenic extraction of He from the CH4 stream step can be eliminated. Heating the gas stream and passing it through selective semi-permeable membranes allow for the helium, with its much smaller size, and higher energy, pass while excluding the relatively massive CH4 molecule. The helium can be isolated and purified via pressure swing adsorption (PSA) methods to achieve 99.999% purity. The heated methane can then be directly ported to a Steam Methane Reformer unit for extraction of hydrogen. Both H2 and He extraction procedures eliminate the need for gas flaring, as both yield salable products such as LNG and NGLs, and the opportunity to capture and sequester carbon dioxide (CO2) from the produced gas stream. This extracted so-called “Blue Hydrogen” is slated for use in transportation via fuel cells or use in internal combustion engines and sells for approximately 3.00/MCF,dependingonthecostofthefeedstocknaturalgas.MetallurgicalheliumorGradeAHelium(i.e.,3˘e99.99993.00/MCF, depending on the cost of the feedstock natural gas. “Metallurgical helium” or “Grade-A Helium” (i.e., \u3e 99.9999% pure), with myriad industrial and scientific uses, brings ~US498/MCF (02-2023). The cost of hydrogen vs. helium extraction is difficult to compare. Hydrogen production depends on the cost of natural gas as a feedstock, which is particularly variable. The cost of helium extraction depends on the volume of gas being processed, as most helium extraction units could handle 10-12 Bakken wells simultaneously. However, as a straight-up market product, helium revenue exceeds hydrogen by a factor of 100. Doing both coincidental from the same gas stream will enhance the revenue of each

    Global Invader Impact Network (GIIN): toward standardized evaluation of the ecological impacts of invasive plants

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    Terrestrial invasive plants are a global problem and are becoming ubiquitous components of most ecosystems. They are implicated in altering disturbance regimes, reducing biodiversity, and changing ecosystem function, sometimes in profound and irreversible ways. However, the ecological impacts of most invasive plants have not been studied experimentally, and most research to date focuses on few types of impacts, which can vary greatly among studies. Thus, our knowledge of existing ecological impacts ascribed to invasive plants is surprisingly limited in both breadth and depth. Our aim was to propose a standard methodology for quantifying baseline ecological impact that, in theory, is scalable to any terrestrial plant invader (e.g., annual grasses to trees) and any invaded system (e.g., grassland to forest). The Global Invader Impact Network (GIIN) is a coordinated distributed experiment composed of an observational and manipulative methodology. The protocol consists of a series of plots located in (1) an invaded area; (2) an adjacent removal treatment within the invaded area; and (3) a spatially separate uninvaded area thought to be similar to pre-invasion conditions of the invaded area. A standardized and inexpensive suite of community, soil, and ecosystem metrics are collected allowing broad comparisons among measurements, populations, and species. The method allows for one-time comparisons and for long-term monitoring enabling one to derive information about change due to invasion over time. Invader removal plots will also allow for quantification of legacy effects and their return rates, which will be monitored for several years. GIIN uses a nested hierarchical scale approach encompassing multiple sites, regions, and continents. Currently, GIIN has network members in six countries, with new members encouraged. To date, study species include representatives of annual and perennial grasses; annual and perennial forbs; shrubs; and trees. The goal of the GIIN framework is to create a standard yet flexible platform for understanding the ecological impacts of invasive plants, allowing both individual and synthetic analyses across a range of taxa and ecosystems. If broadly adopted, this standard approach will offer unique insight into the ecological impacts of invasive plants at local, regional, and global scales.Fil: Barney, Jacob N. Virginia Tech. Department of Plant Pathology, Physiology, and Weed Science; Estados UnidosFil: Tekiela, Daniel R. Virginia Tech. Department of Plant Pathology, Physiology, and Weed Science; Estados UnidosFil: Barrios Garcia Moar, Maria Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. CENAC-APN; ArgentinaFil: Dimarco, Romina Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas-Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo de Ecología de Poblaciones de Insectos; ArgentinaFil: Hufbauer, Ruth A. Colorado State University. Department of Bioagricultural Sciences and Pest Management and Graduate Degree Program in Ecology; Estados UnidosFil: Leipzig-Scott, Peter. Colorado State University. Department of Bioagricultural Sciences and Pest Management and Graduate Degree Program in Ecology; Estados UnidosFil: Nuñez, Martin A. Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad del Comahue. INIBIOMA. Laboratorio de Ecotono; ArgentinaFil: Pauchard, Anibal. Universidad de Concepción. Facultad de Ciencias Forestales. Laboratorio de Invasiones Biolóogicas; Chile. Institute of Ecology and Biodiversity (IEB); ChileFil: Pysek, Petr. The Czech Academy of Sciences. Institute of Botany. Department of Invasion Ecology; República Checa. Charles University in Prague. Faculty of Science. Department of Ecology; República ChecaFil: Viıtkov, Michaela. The Czech Academy of Sciences. Institute of Botany. Department of Invasion Ecology; República ChecaFil: Maxwell, Bruce D. Montana State University. Department of Land Resources and Environmental Sciences; Estados Unido

    Assessing the Permeability of Engineered Capillary Networks in a 3D Culture

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    Many pathologies are characterized by poor blood vessel growth and reduced nutrient delivery to the surrounding tissue, introducing a need for tissue engineered blood vessels. Our lab has developed a 3D co-culture method to grow interconnected networks of pericyte-invested capillaries, which can anastamose with host vasculature following implantation to restore blood flow to ischemic tissues. However, if the engineered vessels contain endothelial cells (ECs) that are misaligned or contain wide junctional gaps, they may function improperly and behave more like the pathologic vessels that nourish tumors. The purpose of this study was to test the resistance to permeability of these networks in vitro, grown with different stromal cell types, as a metric of vessel functionality. A fluorescent dextran tracer was used to visualize transport across the endothelium and the pixel intensity was quantified using a customized MATLAB algorithm. In fibroblast-EC co-cultures, the dextran tracer easily penetrated through the vessel wall and permeability was high through the first 5 days of culture, indicative of vessel immaturity. Beyond day 5, dextran accumulated at the periphery of the vessel, with very little transported across the endothelium. Quantitatively, permeability dropped from initial levels of 61% to 39% after 7 days, and to 7% after 2 weeks. When ECs were co-cultured with bone marrow-derived mesenchymal stem cells (MSCs) or adipose-derived stem cells (AdSCs), much tighter control of permeability was achieved. Relative to the EC-fibroblast co-cultures, permeabilities were reduced 41% for the EC-MSC co-cultures and 50% for the EC-AdSC co-cultures after 3 days of culture. By day 14, these permeabilities decreased by 68% and 77% over the EC-fibroblast cultures. Co-cultures containing stem cells exhibit elevated VE-cadherin levels and more prominent EC-EC junctional complexes when compared to cultures containing fibroblasts. These data suggest the stromal cell identity influences the functionality and physiologic relevance of engineered capillary networks

    Potential drug interactions and duplicate prescriptions among ambulatory cancer patients: a prevalence study using an advanced screening method

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    <p>Abstract</p> <p>Background</p> <p>The pharmacotherapeutic treatment of patients with cancer is generally associated with multiple side-effects. Drug interactions and duplicate prescriptions between anti-cancer drugs or interactions with medication to treat comorbidity can reinforce or intensify side-effects.</p> <p>The aim of the present study is to gain more insight into the prevalence of drug interactions and duplicate prescriptions among patients being treated in the outpatient day care departments for oncology and hematological illnesses. For the first time the prevalence of drug interactions with OTC-drugs in cancer patients will be studied. Possible risk factors for the occurrence of these drug-related problems will also be studied.</p> <p>Methods/Design</p> <p>A multicenter cross-sectional observational study of the epidemiology of drug interactions and duplicate prescriptions is performed among all oncology and hemato-oncology patients treated with systemic anti-cancer drugs at the oncology and hematology outpatient day care department of the VU University medical center and the Zaans Medical Center.</p> <p>Discussion</p> <p>In this article the prevalence of potential drug interactions in outpatient day-care patients treated with anti-cancer agents is studied using a novel more extensive screening method. If this study shows a high prevalence of drug interactions clinical pharmacists and oncologists must collaborate to develop a pharmaceutical screening programme, including an automated electronic warning system, to support drug prescribing for ambulatory cancer patient. This programme could minimize the occurrence of drug related problems such as drug interactions and duplicate prescriptions, thereby increasing quality of life.</p> <p>Trial registration</p> <p>This study is registered, number NTR2238.</p

    The economics of debt clearing mechanisms

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    We examine the evolution of decentralized clearinghouse mechanisms from the 13th to the 18th century; in particular, we explore the clearing of non- or limitedtradable debts like bills of exchange. We construct a theoretical model of these clearinghouse mechanisms, similar to the models in the theoretical matching literature, and show that specific decentralized multilateral clearing algorithms known as rescontre, skontrieren or virement des parties used by merchants were efficient in specific historical contexts. We can explain both the evolutionary self-organizing emergence of late medieval and early modern fairs, and its robustness during the 17th and 18th century

    Effiziente Transportketten in Ensorgungsnetzwerken modular und umweltgerecht gestaltet Abschlussbericht

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    SIGLEAvailable from TIB Hannover: F04B1567 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman
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