Search

Aims Garden cress (Lepidium sativum L.), a member of the Cruciferae family, is widely planted worldwide, especially in India, Europe, and the United States. One of the most common mosquito species that carries Plasmodium falciparum is the Anopheles gambiae sensu lato, which may be combated by sprinkling fields with Lepidium sativum seeds. This study aimed to test the Lepidium sativum Linn. seeds extract as an antimicrobial agent against food pathogens. Materials & Methods The active components were extracted from the powdered dry seeds using chloroform, ethyl acetate, methanol, and dichloromethane. The antibacterial activity of various doses of the extracts was evaluated using agar well diffusion. The MIC and MBC for the most effective extract were estimated using tube dilution and subculturing methods. Findings Staphylococcus aureus had an MIC of 1.56mg/ml and a minimum inhibitory concentration (MBC) of 6.52mg/ml, while Salmonella typhi had an MIC of 25mg/ml. At a concentration of 10% L. sativum, the half-life (KDT50) was determined to be 7.34 minutes. Conversely, the half-life of L. sativum oil was only 10.05 minutes when used at the same concentration. Compared to the L. sativum concentrations that resulted in the KDT50 (50 and 10%, respectively), the bendiocarb 0.1% impregnated filter paper performed poorly. Conclusion L. sativum essential oil effectively kills Anopheles gambiae. [ABSTRACT FROM AUTHOR]

Unconventional Shale Energy resources have become an increasingly significant source of oil and natural gas in the United States, Canada and China over the last decade. This rapid growth could not be achieved without research and development activities in this field. Moreover, revolution in unconventional hydrocarbon industries has triggered many research questions from highly engineering aspects to highly political issues in this area. In the current paper, we have attempted to shed a light on the frontier research of this growing knowledge domain. A number of 2489 papers were collected from Science Citation Index-Expanded (SCI-E) and the Social Sciences Citation Index (SSCI) databases. We applied bibliometric methods on collected publications and with the help of CiteSpace III software; co-citation networks of publications were mapped which revealed valuable information on research trends and knowledge gaps existing in this field. Three clusters of intellectual structure identified and analysed and future research opportunities recommended. [ABSTRACT FROM AUTHOR]

This paper investigates sensitivity of US natural gas price with crude oil price changes, using time-varying coefficient models. Identification of the range of variation of the sensitivity of natural gas price to oil price change allows more accurate assessment of upper and minimum risk levels that can be utilised in pricing natural gas derivatives such as gas futures and option contracts, and gas storage facility contracts. [ABSTRACT FROM AUTHOR]

Tremendous progress has been achieved in the last ten years with respect to modeling the combustion of solid propellants. The vastly increased performance of computing capabilities has allowed utilization of calculation approaches that were previously only conceptual. The paper will discuss three areas of emphasis: first, numerical modeling of premixed flames using detailed kinetic mechanisms; second, development of packing models to calculate a geometrical distribution of particles simulating a heterogeneous solid propellant; and finally, calculation of diffusion same effects that are critical in the combustion of AP/hydrocarbon solid propellants. The capability of modeling premixed combustion using detailed kinetic mechanisms has been evolving and successfully applied to solid propellant ingredients based on a one-dimensional approach. Much of the early work was performed at Novosibirsk. The approach allows calculating the burning rate as a function of pressure but also the temperature sensitivity and spatial distributions of temperature and species concentrations. Generalized mechanisms have been developed and applied to many ingredients such as HMX, GAP, RDX, NG, AP, etc. The gas-phase kinetic mechanisms seem to represent the chemistry of these monopropellants and pseudo-propellants consistently well. The burning rates of these monopropellants vary by almost an order of magnitude but are essentially independent of the flame temperature. Various model calculations agree reasonably well with available experimental data. Recent work in the USA has been aimed at describing the geometrical packing of a solid propellant. These models represent significant progress toward such a description. Combining the packing model with a realistic flame model is still a significant challenge. Preliminary results are encouraging, but obviously further work is needed. Also, fundamental calculation of two-dimensional diffusion flames, incorporating realistic kinetics has progressed significantly. Recent results show encouraging promise toward simulating the minute detail involved in determining the burning rates of AP containing propellants. [ABSTRACT FROM AUTHOR]

This paper investigates the basic stylised facts of natural gas price movements using data for the period that natural gas has been traded on an organised exchange and the methodology suggested by Kydland and Prescott (1990). Our results indicate that natural gas prices are procyclical and lag the cycle of industrial production. Moreover, natural gas prices are positively contemporaneously correlated with United States consumer prices and lead the cycle of consumer prices, raising the possibility that natural gas prices might be a useful guide for US monetary policy, like crude oil prices are, possibly serving as an important indicator variable. [ABSTRACT FROM AUTHOR]

Introduction: We used published literature from 2013–2016, to review data regarding the new all oral interferon and ribavirin free direct acting antiviral (DAA’s) treatment regimens. Areas covered: Specifically, this paper will address DAA’s clinical efficacy, their associated patient reported outcomes, their adherence to treatment, and their cost-effectiveness of treatment using studies from the United States. Expert commentary: The current data suggest that cure and elimination of HCV appears to be on the horizon; however, more research is needed to verify similar results from real world practices. Further, research is also needed to overcome the barriers to treatment (lack of education and awareness of HCV, inadequate diagnosis technology, and lack of access and link to care) in order for the elimination of HCV to be obtained. [ABSTRACT FROM PUBLISHER]

BACKGROUND: The International Agency for Research on Cancer (IARC) Monographs program assembles expert working groups who publish a critical review and evaluation of data on agents of interest. These comprehensive reviews provide a unique opportunity to identify research needs to address classification uncertainties. A multidisciplinary expert review and workshop held in 2009 identified research gaps and needs for 20 priority occupational chemicals, metals, dusts, and physical agents, with the goal of stimulating advances in epidemiological studies of cancer and carcinogen mechanisms. Overarching issues were also described. OBJECTIVES: In this commentary we review the current status of the evidence for the 20 priority agents identified in 2009. We examine whether identified Research Recommendations for each agent were addressed and their potential impact on resolving classification uncertainties. METHODS: We reviewed the IARC classifications of each of the 20 priority agents and identified major new epidemiological and human mechanistic studies published since the last evaluation. Information sources were either the published Monograph for agents that have been reevaluated or, for agents not yet reevaluated, Advisory Group reports and literature searches. Findings are described in view of recent methodological developments in Monographs evidence evaluation processes. DISCUSSION: The majority of the 20 priority agents were reevaluated by IARC since 2009. The overall carcinogen classifications of 9 agents advanced, and new cancer sites with either “sufficient” or “limited” evidence of carcinogenicity were also identified for 9 agents. Examination of published findings revealed whether evidence gaps and Research Recommendations have been addressed and highlighted remaining uncertainties. During the past decade, new research addressed a range of the 2009 recommendations and supported updated classifications for priority agents. This supports future efforts to systematically apply findings of Monograph reviews to identify research gaps and priorities relevant to evaluation criteria established in the updated IARC Monograph Preamble. [ABSTRACT FROM AUTHOR]

Objective This paper considers the evidence on whether outdoor secondhand smoke (SHS) is present in hospitality venues at high levels enough to potentially pose health risks, particularly among employees. Data sources Searches in PubMed and Web of Science included combinations of environmental tobacco smoke, secondhand smoke, or passive smoke AND outdoor, yielding 217 and 5,199 results, respectively through June, 2012. Study selection Sixteen studies were selected that reported measuring any outdoor SHS exposures ( particulate matter (PM) or other SHS indicators). Data extraction The SHS measurement methods were assessed for inclusion of extraneous variables that may affect levels or the corroboration of measurements with known standards. Data synthesis The magnitude of SHS exposure (PM2.5) depends on the number of smokers present, measurement proximity, outdoor enclosures, and wind. Annual excess PM2.5 exposure of full-time waitstaff at outdoor smoking environments could average 4.0 to 12.2 µg/m3 under variable smoking conditions. Conclusions Although highly transitory, outdoor SHS exposures could occasionally exceed annual ambient air quality exposure guidelines. Personal monitoring studies of waitstaff are warranted to corroborate these modeled estimates. [ABSTRACT FROM AUTHOR]

Production of carbon nanofibers and nanotubes (CNFs/CNTs) and their composite products is increasing globally. High volume production may increase the exposure risks for workers who handle these materials. Though health effects data for CNFs/CNTs are limited, some studies raise serious health concerns. Given the uncertainty about their potential hazards, there is an immediate need for toxicity data and field studies to assess exposure to CNFs/CNTs. An extensive study was conducted at a facility that manufactures and processes CNFs. Filter, sorbent, cascade impactor, bulk, and microscopy samples, combined with direct-reading instruments, provided complementary information on air contaminants. Samples were analyzed for organic carbon (OC) and elemental carbon (EC), metals, and polycyclic aromatic hydrocarbons (PAHs), with EC as a measure of CNFs. Transmission electron microscopy with energy-dispersive X-ray spectroscopy also was applied. Fine/ultrafine iron-rich soot, PAHs, and carbon monoxide were production byproducts. Direct-reading instrument results were reported previously [Evans DE et al. (Aerosol monitoring during carbon nanofiber production: mobile direct-reading sampling. Ann Occup Hyg 2010;54:514–31.)] Results for time-integrated samples are reported as companion papers in this Issue. OC and EC, metals, and microscopy results are reported here, in Part I, while results for PAHs are reported in Part II [Birch ME. (Exposure and Emissions Monitoring during Carbon Nanofiber Production—Part II: Polycyclic Aromatic Hydrocarbons. Ann. Occup. Hyg 2011; 55: 1037–47.)]. Respirable EC area concentrations inside the facility were about 6–68 times higher than outdoors, while personal breathing zone samples were up to 170 times higher. [ABSTRACT FROM PUBLISHER]

Copyright of CES Medicina Veterinaria & Zootecnica is the property of Universidad CES and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper discusses US participation in the global liquefied natural gas (LNG) market. Although recent US production of natural gas is up, Canadian production is decreasing and LNG imports by the United States have been on the rise. The current US portfolio of LNG importers is described and the future prospects for each of the current importers are discussed. Changing conditions in the global marketplace have resulted in higher prices and more recent declines in US importation of LNG. With temporary increases in US domestic supply and transportation costs rising, the United States will find it increasingly difficult to compete with other global consumers of LNG. Overcapacity of regasification and high prices are pushing the industry into increased integration. Under these conditions, it seems unlikely that consumers of LNG will experience price declines. In addition, because of global reserve distribution, increased reliance on LNG may jeopardise even further US energy security. [ABSTRACT FROM AUTHOR]

Fingerprinting of hydrocarbon products requires high resolution differentiation of individual hydrocarbon compounds in any mixture. This requires the applications of various measuring techniques. In this paper, we have chosen the heavy hydrocarbons in fuels, lubricants and paving material as examples to discuss the methods for chemical characterization and differentiation. In the category most frequently termed "semi-volatile hydrocarbons" with boiling points from about 500°F to 1200°F or higher, there are several families of hydrocarbons, both natural and refined that are not easily distinguished by conventional EPA tests. Among the groups which we will use as examples are asphalts, hydraulic fluid, transmission oil, motor lubricating oils, heating oils, crude oil and coal. These hydrocarbon families are best studied using combined gas chromatography-mass spectrometry in full scan mode and characterizing various homologous series of hydrocarbons at known fragment ions. The hydrocarbon series providing the best information are: (1) N -alkanes; (2) iso-alkanes; (3) steranes; (4) terpanes; (5) polynuclear aromatic hydrocarbons; (6) aromatic steranes; and (7) specific polycyclic compounds. [ABSTRACT FROM AUTHOR]

This paper covers issues of Russia's national security in the Arctic as viewed from the military perspective. It examines the trends in the development of a reliable defense system for this country. It postulates the importance of greater defense capacity in the Russian Arctic, as nATO relentlessly builds up its military forces next to Russian borders, and the US military infrastructure continues to develop. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a compilation of published mineralogic and trace element data from nine gas shales in the United States. Formations analyzed include the Antrim, Bakken, Barnett, Eagle Ford, Haynesville, Marcellus, New Albany, Utica and Woodford. These mineralogic and trace element data can be used to assess the potential for environmental impacts during hydraulic fracturing. Impacts addressed in this study include: 1) the potential for acid rock drainage generation during gas shale weathering, 2) the distribution of trace elements in gas shales and comparison with regulatory guidelines, and 3) the implications for environmental management of well cuttings. The use of the mineralogic data to assess the fracability of the gas shales is also considered. Compilations of the mineralogy and geochemistry of gas shales can be a valuable resource for managing real and perceived environmental problems associated with their exploitation. Comprehensive environmental assessment to fully address these issues, in addition to other potential environmental impacts, will require collection and collation of additional data on the mineralogy and trace element geochemistry of gas and other hydrocarbon producing shales. [Copyright &y& Elsevier]

Objective The Food and Drug Administration is considering regulation of menthol cigarettes. While persons with mental distress are known to smoke cigarettes at high rates, little is known about their use of menthol. The authors examined the association of psychological distress and menthol use in a national sample of adult smokers. Methods Data were from the 2008 and 2009 National Survey on Drug Use and Health. Past month smokers (N=24 157) were categorised for menthol or nonmenthol use. Psychological distress was categorised as none/mild, moderate or severe on the Kessler six-item scale. Results The prevalence of menthol use was higher among individuals with severe psychological distress, women, young adults, African-Americans, Native Hawaiians/Pacific Islanders, persons with fewer years of education and lower income, and the unmarried and uninsured. In a multivariate model controlling for sociodemographic factors, smoking intensity and time to first cigarette, smokers with severe (adjusted OR (AOR) 1.23, 95% CI 1.04 to 1.46, p=0.02) but not moderate (AOR 1.03, 95% CI 0.92 to 1.15, p=0.58) psychological distress were significantly more likely to smoke menthols compared with smokers with none/mild distress. Conclusion An elevated prevalence of menthol use was found among persons with severe psychological distress, suggesting another group that could potentially benefit from the regulation of menthol cigarettes. [ABSTRACT FROM AUTHOR]

Fire investigators may be occupationally exposed to many of the same compounds as the more widely studied fire suppression members of the fire service but are often tasked with working in a given exposure for longer periods ranging from hours to multiple days and may do so with limited personal protective equipment. In this study, we characterize the area air concentrations of contaminants during post-fire investigation of controlled residential fires with furnishings common to current bedroom, kitchen and living room fires in the United States. Area air sampling was conducted during different investigation phases including when investigations might be conducted immediately after fire suppression and extended out to 5 days after the fire. Airborne particulate over a wide range of dimensions, including sub-micron particles, were elevated to potentially unhealthy levels (based on air quality index) when averaged over a 60 min investigation period shortly after fire suppression with median PM2.5 levels over 100 µg/m3 (range 16–498 µg/m3) and median peak transient concentrations of 1,090 µg/m3 (range 200–23,700 µg/m3) during drywall removal or shoveling activities. Additionally, airborne aldehyde concentrations were elevated compared to volatile organic compounds with peak values of formaldehyde exceeding NIOSH ceiling limits during the earliest investigation periods (median 356 µg/m3, range: 140–775 µg/m3) and occasionally 1 day post-fire when the structure was boarded up before subsequent investigation activities. These results highlight the need to protect investigators' airways from particulates when fire investigation activities are conducted as well as during post-fire reconstruction activities. Additionally, vapor protection from formaldehyde should be strongly considered at least through investigations occurring 3 days after the fire and personal formaldehyde air monitoring is recommended during investigations. [ABSTRACT FROM AUTHOR]

Abstract: This paper considers some of the impacts of adopting hydrogen fuel cell powered electric automobiles in the US. The change will need significant adjustments to the electrical generation industry including additional capital and hydrocarbon fuel consumption as well as impacting anthropogenic greenhouse emissions. Examining the use of three fuels to generate hydrogen fuels, using three production methods, distributed in three geographic scenarios, we determine that while the change reduces anthropogenic greenhouse emissions with minimal additional electrical generation capital expenditures, it accelerates the use of natural gas. Electrolysis provides a sustainable, longer-term solution, but requires more capital investment in electrical generation and yields an increase in anthropogenic greenhouse emissions. [Copyright &y& Elsevier]

Abstract: This paper quantifies the theoretical limit of energy consumption for the removal of 20 representative organic contaminants (9 chlorinated alkyl hydrocarbons, 3 chlorinated alkenes, 3 brominated methanes, 5 aromatic hydrocarbons and their derivatives) in the United States Environmental Protection Agency (U.S. EPA) Priority Pollutant List by physical procedures. The general rules of the theoretical limit of energy consumption with different initial concentrations at 298.15K and 1.01325×105 Pa by NRTL, UNIQUAC and Wilson models are obtained from the thermodynamic analysis with our previously established method based on the thermodynamic first and second law. The results show that the waste treatment process needs a high energy consumption and the theoretical limit of energy consumption for organic contaminant removal increases with decreasing initial concentrations in aqueous solutions. The theoretical limit of energy consumption decreases with the more C–H bonds being replaced by C–Cl or C–Br bonds in chlorinated methanes, ethanes, ethenes or brominated methanes except for 1,1,2,2-tetrachloroethane, and the energy consumption for the removal of chlorinated methanes is higher than that of chlorinated ethanes with the same C–H bonds being replaced by C–Cl bonds. For the removal of chlorinated ethenes, brominated methanes and benzene and its derivatives studied, the energy consumption has corresponding relationship with solubility and the energy consumption is higher for the removal of organics with higher solubility. [ABSTRACT FROM AUTHOR]

Abstract: The continuing increases in oil prices have renewed the argument over the real culprits behind these movements. The growth in demand for oil in international markets, especially from the United States and China, is often identified as the main source of consumption pressure on prices, and thus the upward trend in oil prices. This paper uses unit root tests with two endogenous breaks to analyze the characteristics of oil prices, production, and consumption for several countries. By taking into account structural breaks, we find that many countries’ oil consumption and oil prices are stationary, while other countries are not. We also perform causality tests to determine the direction of any possible relationship between oil price and oil consumption and production. Our statistical analysis reveals that production variables cause oil prices, while oil prices tend to cause consumption. As a result, we claim that the blame for the recent fluctuations in oil prices is more appropriately associated with supply factors, not consumption influences. [ABSTRACT FROM AUTHOR]

Abstract: Next generation hydrocarbon biofuels have the potential to fulfill not only the biofuels production mandate of the Energy Independence and Security Act (EISA) of 2007, but also would not have to be exempted from the EISA-mandated increase in the corporate average fuel economy. Producing “green gasoline”, “green diesel” and “green jet fuel” from non-food lignocellulosic feedstocks such as forest waste and agricultural residue, and energy crops such as short rotation trees and perennial grasses grown on marginal or abandoned cropland will substantially lower greenhouse gas emissions and will not affect food prices. In this paper the development of the new paradigm of green gasoline from lignocellulose will be reviewed, the potential pathways to these infrastructure-compatible fuels will be discussed, and critical process design needs will be outlined. [Copyright &y& Elsevier]

In recent years, a number of refineries in western Canada and the United States have discovered the formation of scale or sludge in their distillation towers. The buildup of large amounts of sludge lowers the efficiency of refineries to the point where it must be removed. The process of removing sludge requires that the refinery shut down at a cost of USD millions in lost production to the refinery operators. Analysis of the sludge has revealed that it has an extraordinarily high phosphorus content (8 to 12%). Further investigation into the origin of the phosphorus in the sludge raised concerns that chemicals used in hydrocarbon-fracturing fluids, specifically volatile-phosphorus-containing hydrocarbon gellants, are responsible for the refinery fouling. This paper will discuss how the origin of the volatile-phosphorus in the hydrocarbon gellants has been determined and how a viable, ultralow volatile phosphorus solution for hydrocarbon gelling has been developed. [ABSTRACT FROM AUTHOR]

Abstract: The US Environmental Protection Agency (EPA) banned lead in motor gasoline in 1996. Aviation gasoline was not included in the ban but due to the environmental pollution, the industry is looking for unleaded replacement fuels with a high octane number. Catalytic cracking of renewable biomass-derived raw materials such as vegetable oils could convert them into valuable raw materials such as aromatic hydrocarbons which can be added to the motor and aviation gasoline fuels for the octane number enhancement. This paper distills the systematics of a large number of experimental yields data of canola oil catalytic cracking using HZSM-5 catalyst, for the production of renewable aromatic hydrocarbons obtained at University of Saskatchewan (USK), Canada. The products were mainly gases, organic liquid products (OLPs) and solid coke. The large body of data is organized using an analytical semi-empirical model (ASEM) developed at the University of Florida (UF) that provides a reasonable account using only a small number of adjusted parameters. The model fits very well with the experimental data in the temperature range of 200–600°C. The influence of catalyst types on the conversion of canola oil to aromatic hydrocarbons is also discussed. The analytical methodology should be useful for organizing catalytic cracking yields of other materials containing carbon, hydrogen and oxygen. [Copyright &y& Elsevier]

The Advanced Collaborative Emissions Study (ACES) program required the use of representative heavy-duty diesel engine activity. This need resulted in an engine test schedule creation program, and a schedule of engine modes representative of modern truck usage was developed based on data collected from engines in trucks operated through the heavy heavy-duty diesel truck (HHDDT) chassis schedule. The ACES test schedule included four active modes of truck operation including creep, transient, cruise, and high-speed cruise (HHDDT_S). This paper focuses on Phase 2 of the program, which was to validate and demonstrate the use of the ACES modes in a test cell. Preliminary testing was performed using a 1992 Detroit Diesel Corporation heavy heavy-duty diesel engine (HHDDE) on only the transient mode. On the basis of these results, each mode was modified slightly to suit implementation in a test cell. The locations of "closed throttle" points in the modes were determined through careful examination of the data. These closed throttle points were simulated during testing by adding negative set point torque values to the input file. After modification, all modes were tested during a final ACES modes demonstration period using a 2004 Cummins ISM HHDDE, obtaining three runs for each mode. During testing, carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOx), particulate matter (PM), and hydrocarbon (HC) emissions were measured, and engine control unit (ECU) data were recorded. The new ACES modes did not adopt the Federal Test Procedure (FTP) regression criteria. New regression criteria for acceptability of a run were determined for each mode using the data obtained during testing. [ABSTRACT FROM AUTHOR]

A considerable portion of the world's hydrocarbon endowment is in carbonate reservoirs. Carbonate reservoirs usually exhibit low porosity and may be fractured. These two characteristics along with oil- to mixed-wet rock properties usually result in lowered hydrocarbon-recovery rates. When enhanced-oil-recovery (EOR) strategies are pursued, the injected fluids will likely flow through the fracture network and bypass the oil in the rock matrix. The high permeability in the fracture network and the low equivalent porous volume result in early breakthrough of the injected fluids. Infill-drilling programs and well-conformance strategies--mostly gas and water shutoff--have effectively been used to mitigate the early breakthrough and to increase oil recovery. In most cases, however, 40 to 50% of the original oil in place (OOIP) is not produced. A large number of EOR field projects in carbonate reservoirs have been referenced in the literature since the early 1970s. These field projects demonstrate the technical feasibility of various EOR methods in carbonate reservoirs. However, because of a collapse in oil prices, most of the aforementioned project plans have been abandoned. This paper presents a comprehensive compilation of EOR (gas, chemical, and thermal methods) field experiences in carbonate reservoirs within the US, as an attempt to identify key variables and project design parameters for future evaluation and revitalization of mature carbonate reservoirs. Carbon dioxide (CO2) flooding [continuous or wateralternating gas (WAG)] is the dominant EOR process used in the US. This is because of the high availability of low-cost CO2. CO2 EOR in particular represents the logical first step toward viable geologic carbon storage and sequestration. EOR chemical methods in carbonate reservoirs, especially polymer flooding, have been widely tested in US carbonate reservoirs. However, EOR chemical methods have made a marginal contribution, relatively, in terms of total oil recovered. Our study includes a brief overview of current laboratory (e.g., wettability changes and novel chemical additives) and field (e.g., injectivity enhancement) experiences in EOR chemical methods in carbonate formations. A brief discussion surrounding the screening methods used to identify viable EOR opportunities in carbonate fields on the basis of past and present experiences is also included. [ABSTRACT FROM AUTHOR]

Bedded salt formations are located throughout the U.S., providing valuable storage capacity for natural gas and other hydrocarbons. To increase gas-storage capabilities and provide operators with improved geotechnical design and operating guidelines for these caverns, stability analyses of single-bedded salt caverns have been completed and are described in this paper. This work is a part of integrated efforts initiated and sponsored by the U.S. Department of Energy (DOE), the Gas Technology Institute (GTI), and Pipeline Research Council International, Inc. Numerical geomechanical models have been developed to investigate single-cavern deformation and bedding-plane slip for a variety of cavern configurations. A viscoplastic salt model has been developed based on an empirical creep law developed for the Waste Isolation Pilot Plant (WIPP) Program and combined with a Drucker-Prager model for damage and failure. The nonsalt materials are described with either a traditional Mohr-Coulomb model, or an elastic model, depending on layer properties. A baseline model with specified geometric dimensions is first selected and subjected to 1-year cyclic pressure operations. The amount of damage around the cavern wall and roof is evaluated and used as a comparison in the study. Then, the operations are extended to 15 years to study cavern stability for long-term gas storage and operations. In addition to the baseline model, parametric studies have been performed to investigate cavern damage as a function of salt roof thickness, overburden stiffness, interface properties, and cavern geometries. Each cavern simulation includes I year of pressure cycling with a minimum, mean, and maximum cavern pressure of 6.1 MPa (884.5 psi), 8.8 MPa (1.276 psi) and 14.9 MPa (2,160.5 psi), respectively. Different operation conditions (e.g., hydrostatic, cyclic, and direct-pressure draw-down) are compared and evaluated in terms of cavern stability. These analyses can be a basis to selecting the best salt cavern candidate for gas storage and operations as well as helping to assess critical cavern design parameters for thin-bedded salt formations. [ABSTRACT FROM AUTHOR]

Prince William Sound (PWS), Alaska has an extensive history of human and industrial activity that has produced a complex organic geochemistry record in subtidal sediments of embayments throughout the sound. In addition to contributions from recent oil spills and a regional background of natural petroleum hydrocarbons originating from active hydrocarbon systems in the northern Gulf of Alaska (GOA), pyrogenic and petrogenic PAH were, and continue to be introduced to subtidal sediments at numerous sites of past and present human activities. These sites include villages, fish hatcheries, fish camps and recreational campsites in addition to abandoned settlements, canneries, sawmills, and mines. A holistic approach is used to fingerprint and quantify hydrocarbon contributions from multiple sources in a sediment sample. It involves acquiring a comprehensive understanding of the history of the area to identify potential sources, collection of representative samples, and accurate quantitative analyses of the source and sediment samples for a suite of diagnostic PAH analytes and chemical biomarker compounds. Unlike the deepwater sediments of the sound and GOA, the TOC tool, described elsewhere, does not work as well in some restricted embayments due to their high contents of recent organic matter (ROM). The current study employs a constrained least-squares algorithm to allocate hydrocarbon sources contributing to subtidal sediments collected from PWS embayments in 1991, 1999 and 2000. Results show that sources contributing to the natural petrogenic background are present in the embayments, pyrogenic hydrocarbons including combustion products of diesel are important where human activity was high, and petroleum produced from the Monterey Formation (CA) is present locally. Oil and asphalt shipped from California were widely used for fuel and construction prior to development of the Cook Inlet and North Slope fields. In certain locations that were oiled in 1989, low levels of highly degraded Alaska North Slope crude oil residues attributable to the Exxon Valdez spill remain. [Copyright &y& Elsevier]

The recent formation of a powerful cartel controlling a large portion of the world's oil supply has heightened interest among the developed nations, especially in the United States, in the development of alternative sources of energy. Indeed, the provocation provided by the Organization of Petroleum Exporting Countries (OPEC) will surely hasten the day when much of the world's energy supply will no longer come from fossil fuels, such as coal, oil, and natural gas, but from nuclear power, the sun, and geothermal sources. However, until that day arrives, it is incumbent upon countries such as the United States to exploit efficiently what fossil fuel it has under its political control. Such considerations call attention to the way in which the United States manages its Outer Continental Shelf (OCS) hydrocarbon resources, in particular the hows and whys of U.S. leasing policy in the OCS. The principal questions revolve around the rate of lease offerings and the method of deciding which producer will be given the right to exploit a specific tract. This paper seeks to answer such questions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Higher risk of exposure to environmental health hazards near oil and gas wells has spurred interest in quantifying populations that live in proximity to oil and gas development. The available studies on this topic lack consistent methodology and ignore aspects of oil and gas development of value to public health--relevant assessment and decision-making. OBJECTIVES: We aim to present a methodological framework for oil and gas development proximity studies grounded in an understanding of hydrocarbon geology and development techniques. METHODS: We geospatially overlay locations of active oil and gas wells in the conterminous United States and Census data to estimate the population living in proximity to hydrocarbon development at the national and state levels. We compare our methods and findings with existing proximity studies. RESULTS: Nationally, we estimate that 17.6 million people live within 1,600 m (~1 mi) of at least one active oil and/or gas well. Three of the eight studies overestimate populations at risk from actively producing oil and gas wells by including wells without evidence of production or drilling completion and/or using inappropriate population allocation methods. The remaining five studies, by omitting conventional wells in regions dominated by historical conventional development, significantly underestimate populations at risk. CONCLUSIONS: The well inventory guidelines we present provide an improved methodology for hydrocarbon proximity studies by acknowledging the importance of both conventional and unconventional well counts as well as the relative exposure risks associated with different primary production categories (e.g., oil, wet gas, dry gas) and developmental stages of wells. [ABSTRACT FROM AUTHOR]

Emissions from flares constitute unburned hydrocarbons, carbon monoxide (CO), soot, and other partially burned and altered hydrocarbons along with carbon dioxide (CO2) and water. Soot or visible smoke is of particular concern for flare operators/regulatory agencies. The goal of the study is to develop a computational fluid dynamics (CFD) model capable of predicting flare combustion efficiency (CE) and soot emission. Since detailed combustion mechanisms are too complicated for (CFD) application, a 50-species reduced mechanism, LU 3.0.1, was developed. LU 3.0.1 is capable of handling C4hydrocarbons and soot precursor species (C2H2, C2H4, C6H6). The new reduced mechanism LU 3.0.1 was first validated against experimental performance indicators: laminar flame speed, adiabatic flame temperature, and ignition delay. Further, CFD simulations using LU 3.0.1 were run to predict soot emission and CE of air-assisted flare tests conducted in 2010 in Tulsa, Oklahoma, using ANSYS Fluent software. Results of non-premixed probability density function (PDF) model and eddy dissipation concept (EDC) model are discussed. It is also noteworthy that when used in conjunction with the EDC turbulence-chemistry model, LU 3.0.1 can reasonably predict volatile organic compound (VOC) emissions as well. Implications: A reduced combustion mechanism containing 50 C1–C4species and soot precursors has been developed and validated against experimental data. The combustion mechanism is then employed in the computational fluid dynamics (CFD) of modeling of soot emission and combustion efficiency (CE) of controlled flares for which experimental soot and CE data are available. The validated CFD modeling tools are useful for oil, gas, and chemical industries to comply with U.S. Environmental Protection Agency’s (EPA) mandate to achieve smokeless flaring with a high CE. [ABSTRACT FROM AUTHOR]

Background: The U.S. Food and Drug Administration can set standards for cigarettes that could include reducing their nicotine content. Such a standard should improve public health without causing unintended serious consequences for sub-populations. This study evaluates the effect of progressive nicotine reduction in cigarettes on smoking behavior, toxicant exposure, and psychiatric symptoms in smokers with comorbid mood and/or anxiety disorders using a two-site, two-arm, double-blind, parallel group, randomized controlled trial (RCT) in four phases over 34 weeks.Methods: Adult smokers (N = 200) of 5 or more cigarettes per day will be randomized across two sites (Penn State and Massachusetts General). Participants must have not had a quit attempt in the prior month, nor be planning to quit in the next 6 months, meet criteria for a current or lifetime unipolar mood and/or anxiety disorder based on the structured Mini-International Neuropsychiatric Interview, and must not have an unstable medical or psychiatric condition. After a week of smoking their own cigarettes, participants receive two weeks of Spectrum research cigarettes with usual nicotine content (11.6 mg). After this baseline period, participants will be randomly assigned to continue smoking Spectrum research cigarettes that contain either (a) Usual Nicotine Content (11.6 mg); or (b) Reduced Nicotine Content: the nicotine content per cigarette is progressively reduced from approximately 11.6 mg to 0.2 mg in five steps over 18 weeks. At the end of the randomization phase, participants will be offered the choice to either (a) quit smoking with assistance, (b) continue smoking free research cigarettes, or (c) return to purchasing their own cigarettes, for the final 12 weeks of the study. The primary outcome measure is blood cotinine; key secondary outcomes are: exhaled carbon monoxide, urinary total NNAL- 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and 1-hydroxypyrene, oxidative stress biomarkers including 8-isoprostanes, measures of psychiatric symptoms (e.g., depression, anxiety), smoking behavior and dependence (e.g., cigarette consumption, quit attempts), and health effects (e.g., blood pressure, respiratory symptoms).Discussion: Results from this study will inform FDA on the potential effects of regulating the nicotine content of cigarettes and help determine whether smokers with mood and/or anxiety disorders can safely transition to significantly reduced nicotine content cigarettes.Trial Registration: TRN: NCT01928758 , registered August 21, 2013. [ABSTRACT FROM AUTHOR]

BACKGROUND: The U.S. Environmental Protection Agency (EPA) completed a toxicological review of tetrachloroethylene (perchloroethylene, PCE) in February 2012 in support of the Integrated Risk Information System (IRIS). OBJECTIVES: We reviewed key findings and scientific issues regarding the human health effects of PCE described in the U.S. EPA's Toxicological Review of Tetrachloroethylene (Perchloroethylene). METHODS: The updated assessment of PCE synthesized and characterized a substantial database of epidemiological, experimental animal, and mechanistic studies. Key scientific issues were addressed through modeling of PCE toxicokinetics, synthesis of evidence from neurological studies, and analyses of toxicokinetic, mechanistic, and other factors (tumor latency, severity, and background rate) in interpreting experimental animal cancer findings. Considerations in evaluating epidemiological studies included the quality (e.g., specificity) of the exposure assessment methods and other essential design features, and the potential for alternative explanations for observed associations (e.g., bias or confounding). DISCUSSION: Toxicokinetic modeling aided in characterizing the complex metabolism and multiple metabolites that contribute to PCE toxicity. The exposure assessment approach--a key evaluation factor for epidemiological studies of bladder cancer, non-Hodgkin lymphoma, and multiple myeloma--provided suggestive evidence of carcinogenicity. Bioassay data provided conclusive evidence of carcinogenicity in experimental animals. Neurotoxicity was identified as a sensitive noncancer health effect, occurring at low exposures: a conclusion supported by multiple studies. Evidence was integrated from human, experimental animal, and mechanistic data sets in assessing adverse health effects of PCE. CONCLUSIONS: PCE is likely to be carcinogenic to humans. Neurotoxicity is a sensitive adverse health effect of PCE. [ABSTRACT FROM AUTHOR]

The potential benefits and limitations of deactivating two of four cylinders by cam switching to disable the intake and exhaust valve lift were investigated experimentally on a turbocharged four-cylinder common-rail direct-injection diesel engine. When running on two firing cylinders, at light engine loads (a brake mean effective pressure of 2 bar, based on four-cylinder operation), the brake specific fuel consumption at given engine-out nitrogen oxide levels is comparable with or marginally better than when the engine is running on four cylinders. Cylinder deactivation allowed higher fuel rail pressures to be used to reduce the soot emissions while maintaining the advantages of lower carbon monoxide emissions and lower hydrocarbon emissions. At engine loads with a brake mean effective pressure of up to 3 bar on four cylinders, cylinder deactivation lowered the carbon monoxide and hydrocarbon emissions and raised the exhaust gas temperature by around 120 °C but, at higher loads, the fuel economy deteriorated and the soot and nitrogen oxide emissions increased markedly. The benefits of cylinder deactivation are therefore limited to light-load operating conditions, where the fuel economy is improved, the hydrocarbon and carbon monoxide emissions are reduced and the exhaust gas temperature is raised. [ABSTRACT FROM PUBLISHER]

The discovery of shale oil and gas in North America (the United States and Canada) is considered a ‘game changer’ in the global petroleum industry. It provides an opportunity for the United States to achieve the energy self-reliance it has sought since the 1970s. It is also expected to allow the United States, the largest petroleum consumer and importer globally, to focus its attention on maximizing the economic benefits and comparative advantages of becoming a self-reliant energy state. It could also enable the United States to reprioritize its strategic interests, sharing responsibility for the security of the oil export routes in the Gulf with its European and Asian allies, rather than shouldering that task almost single-handedly, as is presently the case. However, realization of the advantages that North American shale oil and gas discoveries are purported to bring about will depend on whether the depletion rate can be slowed down and minimized and on whether the cost of production can remain competitive compared with that of conventional hydrocarbons. It will also depend on whether the United States will allow a large percentage of its shale petroleum to be exported, rather than be consumed domestically. [ABSTRACT FROM PUBLISHER]

Personal exposure monitoring for select polycyclic aromatic hydrocarbons (PAHs) was performed as part of the National Human Exposure Assessment Survey (NHEXAS) Pilot Study in Baltimore, MD and in four surrounding counties (NHEXAS-Maryland). An objective of this effort was to establish environmental exposure estimates for non-scripted subpopulations involved in their normal activities. Participants, children, and adults (ages 13-84) were randomly selected from urban, suburban, and rural areas near Baltimore. Twenty-four hour PM sample collections (∼5.8 m) were performed using personal environmental monitors. Monitoring was performed for 47 households and 6 sampling Cycles during 1995-1996. A total of 233 personal air samples were available from the participants with eight PAHs speciated (e.g., chrysene, benzo(a)pyrene) as well as an aggregate grouping (total carcinogenic PAHs). Results indicate that ∼50 % of the selected samples had detectable concentrations for 3 to 5 of the individual PAHs depending upon spatial setting. Noted differences were observed between exposure concentrations from individuals living in rural areas as compared to urban/suburban environments. Mean benzo(a)pyrene concentrations were observed to be 0.10 ng/m across the entire sampling population. This represented a value well below the World Health Organization's 1.0 ng/m ambient air guideline for this PAH. [ABSTRACT FROM AUTHOR]

Plastics are an integral part of our modern life and are used in almost all daily activities. Since plastics are synthesized from nonrenewable sources and are generally not biodegradable, waste plastics are the cause of many of the serious environmental problems the world faces today. However, waste plastics can become a source of enormous energy with the correct treatment. According to a recent study performed by the Environmental Protection Agency (EPA) approximately 48 million tons of waste plastic are generated in the USA alone, to be specific PETE-1 (10%), HDPE-2 (19%), PVC-3 (6%), LDPE-4 (23%), PP-5 (14%), PS-6 (9%) and Other-7 (19%). Statistics show that approximately 10% of this plastic is recycled, 25% is incinerated and the remaining 65% is dumped in landfills. Established technology can convert waste plastics into a renewable source of hydrocarbon fuel. This technology plans to acquire waste plastics from City / Local Municipalities and Recycling Facilities. For plastic fuel production purposes the plastics can be collected as commingled or separated into different categories. Another source of large amounts of waste plastic is floating on our oceans and seriously damaging the ecosystem and the environment. Recent studies show that approximately 100 million tons of waste plastic are floating on the Pacific Ocean, creating an island that stretches over an area twice the size of Texas. These waste plastics can be collected using collection vessels. The waste can then be converted into hydrocarbon fuel either in the collection vessel itself or in off-shore facilities, using established technology. [ABSTRACT FROM AUTHOR]

The Desert Research Institute conducted an on-road mobile source emission study at a traffic tunnel in Van Nuys, California, in August 2010 to measure fleet-averaged, fuel-based emission factors. The study also included remote sensing device (RSD) measurements by the University of Denver of 13,000 vehicles near the tunnel. The tunnel and RSD fleet-averaged emission factors were compared in blind fashion with the corresponding modeled factors calculated by ENVIRON International Corporation using U.S. Environmental Protection Agency's (EPA's) MOVES2010a (Motor Vehicle Emissions Simulator) and MOBILE6.2 mobile source emission models, and California Air Resources Board's (CARB's) EMFAC2007 (EMission FACtors) emission model. With some exceptions, the fleet-averaged tunnel, RSD, and modeled carbon monoxide (CO) and oxide of nitrogen (NOx) emission factors were in reasonable agreement (±25%). The nonmethane hydrocarbon (NMHC) emission factors (specifically the running evaporative emissions) predicted by MOVES were insensitive to ambient temperature as compared with the tunnel measurements and the MOBILE- and EMFAC-predicted emission factors, resulting in underestimation of the measured NMHC/NOxratios at higher ambient temperatures. Although predicted NMHC/NOxratios are in good agreement with the measured ratios during cooler sampling periods, the measured NMHC/NOxratios are 3.1, 1.7, and 1.4 times higher than those predicted by the MOVES, MOBILE, and EMFAC models, respectively, during high-temperature periods. Although the MOVES NOxemission factors were generally higher than the measured factors, most differences were not significant considering the variations in the modeled factors using alternative vehicle operating cycles to represent the driving conditions in the tunnel. The three models predicted large differences in NOxand particle emissions and in the relative contributions of diesel and gasoline vehicles to total NOxand particulate carbon (TC) emissions in the tunnel. [ABSTRACT FROM AUTHOR]

Copyright of Foro Internacional is the property of El Colegio de Mexico AC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hydrocarbon mixtures extracted from fecal pellets of drywood termites are species-specific and can be characterized to identify the termites responsible for damage, even when termites are no longer present or are unable to be recovered easily. In structures infested by drywood termites, it is common to find fecal pellets, but difficult to sample termites from the wood. When fecal pellets appear after remedial treatment of a structure, it is difficult to determine whether this indicates that termites in the structure are still alive and active or not. We examined the hydrocarbon composition of workers, alates, and soldiers of Incisitermes minor (Hagen) (family Kalotermitidae) and of fecal pellets of workers. Hydrocarbons were qualitatively similar among castes and pellets. Fecal pellets that were aged for periods of 0, 30, 90, and 365 days after collection were qualitatively similar across all time periods, however, the relative quantities of certain individual hydrocarbons changed over time, with 19 of the 73 hydrocarbon peaks relatively increasing or decreasing. When the sums of the positive and negative slopes of these 19 hydrocarbons were indexed, they produced a highly significant linear correlation ( R = 0.89). Consequently, the quantitative differences of these hydrocarbons peaks can be used to determine the age of worker fecal pellets, and thus help determine whether the colony that produced them is alive or dead. [ABSTRACT FROM AUTHOR]

Semipermeable membrane devices (SPMDs) were deployed in streams along a gradient of urban land-use intensity in and around six metropolitan areas: Atlanta, Georgia; Raleigh–Durham, North Carolina; and Denver–Fort Collins, Colorado, in 2003; and Dallas–Fort Worth, Texas; Milwaukee–Green Bay, Wisconsin; and Portland, Oregon, in 2004 to examine relations between percent urban land cover in watersheds and the occurrence, concentrations, and potential toxicity of hydrophobic compounds. Of the 142 endpoints measured in SPMD dialysates, 30 were significantly (alpha = 0.05) related to the percent of urban land cover in the watersheds in at least one metropolitan area. These 30 endpoints included the aggregated measures of the total number of compounds detected and relative toxicity (Microtox® and P450RGS assays), in addition to the concentrations of 27 individual hydrophobic compounds. The number of compounds detected, P450RGS assay values, and the concentrations of pyrogenic polycyclic aromatic hydrocarbons (PAHs) were significantly related to percent urban land cover in all six metropolitan areas. Pentachloroanisole, the most frequently detected compound, was significantly related to urban land cover in all metropolitan areas except Dallas–Fort Worth. Petrogenic PAHs and dibenzofurans were positively related to percent urban land cover in Atlanta, Raleigh–Durham, Denver, and Milwaukee–Green Bay. Results for other endpoints were much more variable. The number of endpoints significantly related to urban land cover ranged from 6 in Portland to 21 Raleigh–Durham. Based on differences in the number and suite of endpoints related to urban intensity, these results provide evidence of differences in factors governing source strength, transport, and/or fate of hydrophobic compounds in the six metropolitan areas studied. The most consistent and significant results were that bioavailable, aryl hydrocarbon receptor agonists increase in streams as basins become urbanized. Potential toxicity mediated by this metabolic pathway is indicated as an important factor in the response of aquatic biota to urbanization. [ABSTRACT FROM AUTHOR]

The article discusses the field studies on the unusual progression of petroleum degradation in the subsurface environment under the absence of oxygen by the U.S. Geological Survey (USGS). Researches determined that for the C10 petroleum fraction, degradation under methanogenic conditions uses up the longer chain normal alkenes, n-alkylcyclohexanes, and n-alkylbenzenes before the shorter homolog based on the results of the two field studies. In addition, the second discussion discussed the cummulative changes in the chemical composition of petroleum products that resulted from physical and biochemical weathering in subsurface environment.

For many years, fuel switching between natural gas and residual fuel oil kept natural gas prices closely aligned with those for crude oil. More recently, however, the number of U.S. facilities able to switch between natural gas and residual fuel oil has declined, and over the past seven years, U.S. natural gas prices have been on an upward trend with crude oil prices but with considerable independent movement. Natural gas market analysts generally emphasize weather and inventories as drivers of natural gas prices. Using an error-correction model, we show that when these and other additional factors are taken into account, movements in crude oil prices have a prominent role in shaping natural gas prices. Our findings imply a continuum of prices at which natural gas and petroleum products are substitutes. [ABSTRACT FROM AUTHOR]

Road traffic is one of the major anthropogenic emission sectors for NOx, CO and NMHCs (non-methane hydrocarbons). We applied ECHAM4/CBM, a general circulation model coupled to a chemistry module, which includes higher hydrocarbons, to investigate the global impact of 1990 road traffic emissions on the atmosphere. Improving over previous global modelling studies, which concentrated on road traffic NOx and CO emissions only, we assess the impact of NMHC emissions from road traffic. It is revealed that NMHC emissions from road traffic play a key role for the impact on ozone. They are responsible for (indirect) long-range transport of NOx from road traffic via the formation of PAN, which is not found in a simulation without NMHC emissions from road traffic. Long-range transport of NMHC-induced PAN impacts on the ozone distribution in Northern Hemisphere regions far away from the sources, especially in arctic and remote maritime regions. In July total road traffic emissions (NOx, CO and NMHCs) contribute to the zonally averaged ozone distribution by more than 12% near the surface in the Northern Hemisphere midlatitudes and arctic latitudes. In January road traffic emissions contribute near the surface in northern and southern extratropics more than 8%. Sensitivity studies for regional emission show that effective transport of road traffic emissions occurs mainly in the free troposphere. In tropical latitudes of America up to an altitude of 200 hPa, global road traffic emissions contribute about 8% to the ozone concentration. In arctic latitudes NMHC emissions from road transport are responsible for about 90% of PAN increase from road transport, leading to a contribution to ozone concentrations of up to 15%. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluates the content of mild-solvent extracted fraction of the polycyclic aromatic hydrocarbons in the rhizospheres of some selected plant species (Cucumis sativa, Daucus carota, Allium cepa, Cucurbita pepo, Petroselinum sativum, Cucurbita sp., Phaseolus vulgaris, Beta vulgaris, Apium graveolens, Allium porrum, Vicia faba). Ten compounds from the US EPA list (phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chryzene, benzo[b]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene oraz indeno[1,2,3-cd]pyrene) were chosen. The polycyclic aromatic hydrocarbon (PAH) content was determined using the HPLC method with UV detection after a preliminary sample treatment with ultrasonic techniques. On the basis of the PAH content, the organic carbon content and the value of log Koc, (equilibrium partitioning model) a soil pore water PAH fractions present in the rhizospheres of the plants studied were calculated too. The content of the fraction extracted with n-butanol within the total of 10 PAHs ranged from 55% to 90% (mean 74%). Similarly, as in the case of the total of the 10 PAHs, significant differences in the content of PAHs extracted with n-butanol were also noted for the individual compounds studied. The content of the total of the 10 PAHs as determined from equilibrium partitioning model in relation to plant species ranged from 0.03 to 0.18 µg/kg which constituted from 0.07% to 0.15% of the total content of these compounds. No clear relations between soil properties and the content or contribution of potentially bio-available PAH fractions have been observed. [ABSTRACT FROM AUTHOR]

Since the early 2000s the United States and the European Union have increasingly sought to develop hydrocarbon resources beneath the Caspian Sea in order to reduce their heavy dependency on supplies from the Middle East. The goal is to reduce the West's energy vulnerability and enhance its energy security. This essay seeks to examine the Caspian Sea states' oil and natural gas potential. Energy security is defined as sustainable and reliable supplies at reasonable prices. The argument is two‐fold. First, the Caspian Sea suffers from several drawbacks, particularly the lack of consensus on a legal status of the sea and the construction of pipelines. Second, these drawbacks aside, energy security should not be addressed as one supplier replacing another. The Caspian Sea states' production potential is limited in comparison with that of the Middle East. Thus, the Caspian Sea should be seen as a supplement, not a replacement, to the Middle East. Still, production from Central Asia would contribute to the diversity of oil and natural gas supplies and enhance global energy security. [ABSTRACT FROM AUTHOR]

Total Petroleum Hydrocarbons (TPH) is a non-specific parameter defined by EPA Method 418.1. The method is simple, inexpensive and straightforward. Freon 113 is used to extract petroleum from the matrix. The Montreal Protocol precludes the production and importation of Freon 113 into the United States. The search for a cost-effective replacement is underway. US EPA method 1664A Silica Gel Treated N-Hexane Extractable Material (SGT-HEM: Non-Polar Materials) has been considered as a replacement for Method 418.1 by some persons. No comparison data has been provided. The Tosco Corp. Bayway Refinery has a wastewater discharge permit for Petroleum Hydrocarbons (Oil & Grease) that specifies the use of Method 418.1. The intent of this study was to determine if Method 1664A could replace Method 418.1. Method 418.1 is a direct instrumental measurement of the dried extract. Method I664A is a gravimetric measurement that requires heating the extract to remove the solvent. Also, a key question to be answered is what carbon range petroleum hydrocarbons does heating the extracts lose? Several evaporation procedures and temperatures were studied. The study showed that the recovery of petroleum hydrocarbons by method 1664A is temperature dependent and that under the study conditions the method 1664A Silica Gel Treated N-Hexane Extractable Material (SGT-HEM; Non-Polar Materials) can be a replacement for method 418.1. [ABSTRACT FROM AUTHOR]

Reports on the U.S. Department of Energy/Petroleum Environmental Research Forum (PERF) vapor pathway workshop held in California on January 2004. Vapor pathwa issues for oil companies; Sampling techniques; Impact of background concentration on indoor air and source apportionment; Potential use of microbial techniques in understanding hydrocarbon degradation and methane production; Isotope fractionation techniques and source identification.

Nonmethane organic compounds (NMOCs) along with ozone as well as other trace gas and meteorological parameters were measured at eight rural sites located in the Southeast United States, as part of the Southern Oxidants Study. Fifty-four C[sub 2]–C[sub 10] NMOCs were collected from 1,200–1,300 local time, once every six days from September 1992 through October 1993 and intermittently during 1994. This study was undertaken to characterize the nonmethane hydrocarbons in the rural areas of Southeast United States with respect to their concentrations, reactivities, and relative importance of natural and anthropogenic abundances of NMOCs. Though the sites are well removed from large urban source regions, the observations show a clear anthropogenic influence on the hydrocarbon levels at these rural sites. The data for the sites show similar seasonal patterns for total NMOC with summer maxima (average concentrations of 198 ppbC at the Long Creek, South Carolina, site to 47 ppbC at the Candor, North Carolina site) and fall minima (average concentrations of 73 ppbC at the Long Creek site to 31 ppbC at the Centreville, Alabama site). A secondary maximum is observed during the winter. A seasonal trend was observed in the concentrations of light molecular weight C[sub 2]–C[sub 4] NMOCs (ethane, ethene, acetylene, propane, i-butane, and n-butane) with a winter maximum and a summer minimum. An analysis of changes in C[sub 2]–C[sub 4] hydrocarbon ratios over a period of one year indicates that the variation is most likely due to seasonal changes in OH concentrations. A seasonal trend was also observed for the biogenically emitted NMOC, isoprene, with summer maxima (average concentrations of 37 ppbC at the Long Creek, South Carolina, site to 8.6 ppbC at the Giles County, Tennessee and Metter, Georgia, sites) and winter minima with winter seasonal values below the level of detection. Isoprene was observed to be the most dominant NMOC at most sites during the summer. The ambient concentrations of isoprene measured during the summer were found to be dependent on the ambient temperature. The monoterpenes a-pinene, b-pinene, and d-limonene also peaked during the summer with averages ranging between 3.19 ppbC (Centreville, Alabama) and 6.38 ppbC (Oak Grove, Missouri), and a background concentration of 1.25 to 1.9 ppbC for all the sites during the winter. [ABSTRACT FROM AUTHOR]

In this study, we determined the biologic activity of dichloromethane-extracted particulate matter < 10 µm in aerodynamic diameter (PM[sub 10]) obtained from filters at three sites in the Paso del Norte airshed, which includes El Paso, Texas, USA; Juarez, Chihuahua, Mexico, and Sunland Park, New Mexico, USA. The extracts were rich in polycyclic aromatic hydrocarbons (PAHs) and had significant biologic activity, measured using two in vitro assay systems: ethoxyresorufin-O-deethylase (EROD) induction and the aryl hydrocarbon-receptor luciferase reporter system. In most cases, both EROD (5.25 pmol/min/mg protein) and luciferase activities (994 relative light units/mg) were highest in extracts from the Advance site located in an industrial neighborhood in Juarez. These values represented 58% and 55%, respectively, of induction associated with 1 µM β-naphthoflavone exposures. In contrast, little activity was observed at the Northeast Clinic site in El Paso, the reference site. In most cases, luciferase and EROD activity from extracts collected from the Tillman Health Center site, situated in downtown El Paso, fell between those observed at the other two sites. Overall, a statistically significant correlation existed between PM[sub 10] and EROD and luciferase activities. Chemical analysis of extracts collected from the Advance site demonstrated that concentrations of most PAHs were higher than those reported in most other metropolitan areas in the United States. Calculations made with these data suggest a cancer risk of 5-12 cases per 100,000 people. This risk estimate, as well as comparisons with the work of other investigators, raises concern regarding the potential for adverse health effects to the residents of this airshed. Further work is needed to understand the sources, exposure, and effects of PM[sub 10] and particulate organic material in the Paso del Norte airshed. [ABSTRACT FROM AUTHOR]

Partial least squares (PLS) techniques are used in the re-analysis of NOAA hydrocarbon data previously investigated in . New data have been provided for coal and oil signatures and these have been investigated further. The effects of zeros (less than the limit of detection) in the dataset can be overcome by addition of small values at approximately half of this limit; this then enables logarithms to be taken of the entire dataset which greatly improved the usefulness of principal component analysis (PCA). Source samples collected close to each other had different signatures, probably due to their environmental histories which was also seen when aliphatic hydrocarbons were included in the signatures. Key compounds describing each could be seen in Coomans'' Plots. Signatures developed from formation oils, riperian oils and coals from the eastern Gulf of Alaska (GoA) provided mean fits to subtidal samples within PWS of 22, 19 and 38% respectively. This suggests mixed and variable sources across the sampling area. The overall conclusion must be a question regarding the partitioning between oil and coal source materials as they look very similar in this particular location. [Copyright &y& Elsevier]

The successful application of forensic geology to contamination studies involving natural systems requires identification of appropriate endmembers and an understanding of the geologic setting and processes affecting the systems. Studies attempting to delineate the background, or natural, source for hydrocarbon contamination in Gulf of Alaska (GOA) benthic sediments have invoked a number of potential sources, including seep oils, source rocks, and coal. Oil seeps have subsequently been questioned as significant sources of hydrocarbons present in benthic sediments of the GOA in part because the pattern of relative polycyclic aromatic hydrocarbon (PAH) abundance characteristic of benthic GOA sediments is inconsistent with patterns typical of weathered seep oils. Likewise, native coal has been dismissed in part because ratios of labile hydrocarbons to total organic carbon (e.g. PAH:TOC) for Bering River coal field (BRCF) sources are too low—i.e. the coals are over mature—to be consistent with GOA sediments. We present evidence here that native coal may have been prematurely dismissed, because BRCF coals do not adequately represent the geochemical signatures of coals elsewhere in the Kulthieth Formation. Contrary to previous thought, Kulthieth Formation coals east of the BRCF have much higher PAH:TOC ratios, and the patterns of labile hydrocarbons in these low thermal maturity coals suggest a possible genetic relationship between Kulthieth Formation coals and nearby oil seeps on the Sullivan anticline. Analyses of low-maturity Kulthieth Formation coal indicate the low maturity coal is a significant source of PAH. Source apportionment models that neglect this source will underestimate the contribution of native coals to the regional background hydrocarbon signature. [Copyright &y& Elsevier]