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This paper presents an analysis of the problem of reorientation of a riser pipe from an initially horizontal configuration during subsurface tow to the vertical position for installation. Front and rear barges support the pipe through cables. The orientation into a vertical configuration is accomplished by paying out the front cable. The pipe is treated as a Bernoulli-Euler beam with significant tension undergoing large angle deflections. A finite element procedure used state transfer matrices and successive linearization and the results show that the stress critical phase occurs when the pipe is going through the 60-deg angle to the horizontal direction.

Abstract Microorganisms used in syngas fermentation require nutrients to grow and convert syngas (CO, H2 and CO2) into various products. Many of the essential nutrients can be provided by biochar. Poultry litter biochar (PLBC) contains minerals and trace metals and has a high pH buffering capacity, making it suitable as a nutrient supplement. The effects of PLBC loadings from 1 to 20 g L−1 on syngas fermentation were determined in 250 ml bottle assays. Results showed that 10 and 20 g L−1 PLBC significantly increased ethanol production compared to standard yeast extract (YE) medium. Fermentations in a 3L continuous stirred tank reactor (CSTR) with 10 g L−1 PLBC with and without 4-morpholineethanesulfonic acid (MES) showed 64% and 36% more ethanol production, respectively, than standard medium. The acetic acid accumulated at the beginning of fermentation was completely converted to ethanol in all media tested in the CSTR. These results demonstrate the feasibility of using PLBC medium without costly MES in the CSTR to enhance ethanol production from syngas for potential use at commercial scale.

Energy is consumed at every stage of the cycle of water production, distribution, end use, and recycled water treatment. Understanding the nexus of energy and water may help to minimize energy and water consumption and reduce environmental emissions. However, the interlinkages between water and energy have not received adequate attention. To address this gap, this paper disaggregates and quantifies the energy consumption of the entire water cycle process in Beijing. The results of this study show that total energy consumption by water production, treatment and distribution, end use, and recycled water reuse amounts to 55.6 billion kWh of electricity in 2015, or about 33% of the total urban energy usage. While water supply amount increased by only 10% from 2005 to 2015, the related energy consumption increased by 215% due to water supply structural change. The Beijing municipal government plans to implement many water saving measures in the area from 2016 to 2020, however, these policies will increase energy consumption by 74 million kWh in Beijing. This study responds to the urgent need for research on the synergies between energy and water. In order to achieve the goal of low-energy water utilization in the future, water and energy should be integrated in planning and management.

Electrical submersible pumps (ESPs) are widely used in upstream oil production. The presence of a low concentration solid phase, particle-laden flow, in the production fluid may cause severe damage in the internal sections of the pump which reduces its operating lifetime. To better understand the ESP pump's endurance, two different designs of commonly used mixed flow ESPs were studied numerically to determine the pump's flow behavior at its best efficiency point. Computational fluid dynamics (CFD) analysis was conducted on two stages of one design type of pump's primary flow path employing Eulerian–Granular scheme in ANSYS FLUENT. The key parameters affecting the erosion phenomena within the pump such as turbulence kinetic energy, local sand concentration, and near wall relative sand velocity were identified. The predictive erosion model applicable to pumps was developed by correlating the erosion key parameters with available experimental results. It is concluded that the use of an erosion model on the second design of ESP proves the model's versatility to predict the erosion on different designs of ESPs.

A promising route to transition wastewater treatment facilities (WWTFs) from energy-consuming to net energy-positive is to retrofit existing facilities with process modifications, residual biosolid upcycling, and effluent thermal energy recovery. This study assesses the economics and life cycle environmental impacts of three proposed retrofits of WWTFs that consider thermochemical conversion technologies, namely, hydrothermal liquefaction, slow pyrolysis, and fast pyrolysis, along with advanced bioreactors. The results are in turn compared to the reference design, showing the retrofitting design with hydrothermal liquefaction, and an up-flow anaerobic sludge blanket has the highest net present value (NPV) of $177.36MM over a 20-year plant lifetime despite 15% higher annual production costs than the reference design. According to the ReCiPe method, chlorination is identified as the major contributor for most impact categories in all cases. There are several uncertainties embedded in the techno-economic analysis and life cycle assessment, including the discount rate, capital investment, sewer rate, and prices of main products; among which, the price of biochar presents the widest variation from $50 to $1900/t. Sensitivity analyses reveal that the variation of discount rates causes the most significant changes in NPVs. The impact of the biochar price is more pronounced in the slow pyrolysis-based pathway compared to the fast pyrolysis since biochar is the main product of slow pyrolysis.

Common to the Committee on Statistics of Drilling District 12 area are the recent exploration activities associated with the Central North American rift system or Mid-Continent geophysical anomaly (MGA), a major feature that runs from the Lake Superior area south into Kansas. For the last several years, much preliminary geologic and geophysical work has been undertaken, which usually proceeds a major play. The primary purpose is to test the Cambrian and Precambrian sediments know to have oil seeps in Wisconsin and Michigan. In 1984, Texaco USA drilled the first deep test, which was in Kansas. Although the well was apparently a dry hole, Texaco's findings have not been released. Kansas had a very active year with 7,451 completions, 45 more than those reported in 1983. The success rate of all wells drilled for oil or gas (7,307) was 57.5%, down slightly from 59.3% in 1983. Drilling for oil continued to predominate with 3,783 oil wells and 419 gas wells completed. Total footage was 22,486,535, up 4% from 1983. The average depth of a test drilled for oil or gas was 3,026 ft. In Missouri, the number of wells drilled for oil or gas declined 17% from 1983 levels. Most drilling continued to be in the western part of the state. A deep test in Vernon County penetrated 2,080 ft of Precambrian rocks. In Nebraska, 12 new discoveries were made in the western part of the state. Seven found new oil reserves, and 5 were tight holes; all were classified as new-field wildcats. The average depth was 5,465 ft in the 7 discoveries where the operator reported the total depth. In Mills County, Iowa, 4 wildcats were drilled to the Cambrian with depths from 3,000 to 3,300 ft. All were located approximately 35 mi north of the Tarkio field in northwestern Missouri. It is estimated that 2,000,000 ac are leased in Iowa along the MGA. In Minnesota, 400,000 ac were leased during 1984. The leases were concentrated mainly along the MGA from Duluth to the Iowa border. About 1,000 mi of Vibroseis was run across this feature. In Wisconsin, regional geophysical surveys along the MGA have been run. Companies are now doing more detailed seismic work. Acreage leased from October 1983 to January 1985 was estimated at 214,000 ac. A dry hole was drilled 1,000 ft into quartzite in Barron County.

We utilize a variety of climate datasets to examine impacts of two mechanisms on precipitation in the Greater Horn of Africa (GHA) during northern-hemisphere summer. First, surface-pressure gradients draw moist air toward the GHA from the tropical Atlantic Ocean and Congo Basin. Variability of the strength of these gradients strongly influences GHA precipitation totals and accounts for important phenomena such as the 1960s–1980s rainfall decline and devastating 1984 drought. Following the 1980s, precipitation variability became increasingly influenced by the southern tropical Indian Ocean (STIO) region. Within this region, increases in sea-surface temperature, evaporation, and precipitation are linked with increased exports of dry mid-tropospheric air from the STIO region toward the GHA. Convergence of dry air above the GHA reduces local convection and precipitation. It also produces a clockwise circulation response near the ground that reduces moisture transports from the Congo Basin. Because precipitation originating in the Congo Basin has a unique isotopic signature, records of moisture transports from the Congo Basin may be preserved in the isotopic composition of annual tree rings in the Ethiopian Highlands. A negative trend in tree-ring oxygen-18 during the past half century suggests a decline in the proportion of precipitation originating from the Congo Basin. This trend may not be part of a natural cycle that will soon rebound because climate models characterize Indian Ocean warming as a principal signature of greenhouse-gas induced climate change. We therefore expect surface warming in the STIO region to continue to negatively impact GHA precipitation during northern-hemisphere summer.

Abstract The Oil and Gas industry is becoming more adept in reducing its impact on the environment and in showing optimal use of resources. This approach to environmentally friendly drilling offers the two-fold advantage of the reduction of the footprint of drilling operations while realizing savings by reducing waste treatment, hauling and remediation costs. The Harold Vance Department of Petroleum Engineering at Texas A&M University has incorporated an Environmentally Friendly Drilling System (EFD) design into its PE 661 graduate drilling class. The "661 Team Challenge" semester project was assigned to the students to "design a well on paper" using low impact drilling technology. A systems engineering optimization protocol approach was utilized to incorporate a number of current and emerging EFD technologies into a single clean drilling system with no or very limited environmental impact. A web-based decision optimization tool was developed to follow the systems approach technology evaluation procedure and select an optimal system. The resulting well designs were judged as to their suitability for implementation in a protected wetland on the Texas Gulf Coast. Introduction The Harold Vance Department of Petroleum Engineering at Texas A&M University offers a series of five graduate courses designed to introduce Petroleum Engineering to new graduate students with a limited Petroleum Engineering Background. One of these courses is PETE 661 Drilling Engineering where we teach "drilling for non-drillers". Although this course is designed for non-drillers, there are a number of students with considerable experience in drilling who take the course as a refresher or for exposure to an alternate view of Drilling Engineering.

Reoxidation and mobilization of previously reduced and immobilized uranium by dissolved-phase oxidants poses a significant challenge for remediating uranium-contaminated groundwater. Preferential oxidation of reduced sulfur-bearing species, as opposed to reduced uranium-bearing species, has been demonstrated to limit the mobility of uranium at the laboratory scale yet field-scale investigations are lacking. In this study, the mobility of uranium in the presence of nitrate oxidant was investigated in a shallow groundwater system after establishing conditions conducive to uranium reduction and the formation of reduced sulfur-bearing species. A series of three injections of groundwater (200 L) containing U(VI) (5 μM) and amended with ethanol (40 mM) and sulfate (20 mM) were conducted in ten test wells in order to stimulate microbial-mediated reduction of uranium and the formation of reduced sulfur-bearing species. Simultaneous push-pull tests were then conducted in triplicate well clusters to investigate the mobility of U(VI) under three conditions: 1) high nitrate (120 mM), 2) high nitrate (120 mM) with ethanol (30 mM), and 3) low nitrate (2 mM) with ethanol (30 mM). Dilution-adjusted breakthrough curves of ethanol, nitrate, nitrite, sulfate, and U(VI) suggested that nitrate reduction was predominantly coupled to the oxidation of reduced-sulfur bearing species, as opposed to the reoxidation of U(IV), under all three conditions for the duration of the 36-day tests. The amount of sulfate, but not U(VI), recovered during the push-pull tests was substantially more than injected, relative to bromide tracer, under all three conditions and further suggested that reduced sulfur-bearing species were preferentially oxidized under nitrate-reducing conditions. However, some reoxidation of U(IV) was observed under nitrate-reducing conditions and in the absence of detectable nitrate and/or nitrite. This suggested that reduced sulfur-bearing species may not be fully effective at limiting the mobility of uranium in the presence of dissolved and/or solid-phase oxidants. The results of this field study confirmed those of previous laboratory studies which suggested that reoxidation of uranium under nitrate-reducing conditions can be substantially limited by preferential oxidation of reduced sulfur-bearing species.