sCO2 Compression

TutorialSupercritical Carbon Dioxide (sCO2) power cycles are a transformational technology for the energy industry, providing higher thermal efficiency compared to traditional heat-source energy conversion including conventional fossil and alternative energy sources. The novel cycle significantly reduces capital costs due to smaller equipment footprints and design modularity. In addition, it allows for rapid cyclic load and source following to balance solar and wind energy power swings. Compressing CO2 is not novel, but mostly at lower vapor pressures, and at higher pressure and lower temperatures as a liquid. Compression near the dome (near critical pressure and temperature) is a new interest that has many advantages and challenges. The key advantage is the low head requirement when compressing near the CO2 dome (95oF [35oC] and 1,233 psi [8.5 MPa]). To pressurize from 1,233 psi (target inlet pressure of power cycles) to 3,916 psi (27.0 MPa), only a single high-speed compressor stage is required. This low head requirement means less power is required to compress and leads to an increase in thermal efficiency of these cycles. High-efficiency compression technology can reduce the power of Enhanced Oil Recovery (EOR) and Carbon Capture and Sequestration (CCS) applications. This type of compression also brings many challenges. A compressor for this application pushes many current technology limits, including but not limited to: pressure rise per stage, bearing technologies, sealing technologies, damping, rotordynamics, compact machinery packaging, and high-density, high-speed compression. In addition, when compressing near the CO2 dome, there are large swings in density for slight changes in temperature. This is a unique challenge not observed when CO2 is pumped as a liquid or compressed as a vapor. Due to these large changes in density, range extension is required to maintain high compression efficiency and controlled mass flow over a range of operating temperatures. Recent testing finished on a state-of-the-art sCO2 compressor operating near the dome that was designed, manufactured, and tested by Southwest Research Institute (SwRI) and General Electric Global Research (GE-GRC). This tutorial will highlight many of the unique aspects of the design, especially those challenges and decisions that were focused on high pressure ratio compression stages, high-density and high-speed flow, special rotordynamic considerations, and the overall challenges of compact high-pressure turbomachinery. It will then cover how the design and analysis translated to testing with a real gas that experiences rapid changes in fluid properties for minimal fluctuations in temperature. In addition, due to its need for compact, high-power, and high-speed machinery, the development of sCO2 machinery aids in the development of many advanced components and hardware that can also be used in other applications. This includes high-pressure and high-temperature end seals, zero- to low-emission seals, hermetically sealed systems with gas or magnetic bearings, high-pressure single stage compressors, range extension technologies like variable Inlet Guide Vanes (IGVs), and high-density and high-critical speed ratio operation

Maternal protein-energy malnutrition during early pregnancy in sheep impacts the fetal ornithine cycle to reduce fetal kidney microvascular development

This paper identifies a common nutritional pathway relating maternal through to fetal protein-energy malnutrition (PEM) and compromised fetal kidney development. Thirty-one twin-bearing sheep were fed either a control (n=15) or low-protein diet (n=16, 17 vs. 8.7 g crude protein/MJ metabolizable energy) from d 0 to 65 gestation (term, ∼ 145 d). Effects on the maternal and fetal nutritional environment were characterized by sampling blood and amniotic fluid. Kidney development was characterized by histology, immunohistochemistry, vascular corrosion casts, and molecular biology. PEM had little measureable effect on maternal and fetal macronutrient balance (glucose, total protein, total amino acids, and lactate were unaffected) or on fetal growth. PEM decreased maternal and fetal urea concentration, which blunted fetal ornithine availability and affected fetal hepatic polyamine production. For the first time in a large animal model, we associated these nutritional effects with reduced micro- but not macrovascular development in the fetal kidney. Maternal PEM specifically impacts the fetal ornithine cycle, affecting cellular polyamine metabolism and microvascular development of the fetal kidney, effects that likely underpin programming of kidney development and function by a maternal low protein diet

Cenozoic Antarctic DiatomWare/BugCam: An aid for research and teaching

Cenozoic Antarctic DiatomWare/BugCam© is an interactive, icon-driven digital-imagedatabase/software package that displays over 500 illustrated Cenozoic Antarctic diatom taxa along with original descriptions (including over 100 generic and 20 family-group descriptions). This digital catalog is designed primarily for use by micropaleontologists working in the field (at sea or on the Antarctic continent) where hard-copy literature resources are limited. This new package will also be useful for classroom/lab teaching as well as for any paleontologists making or refining taxonomic identifications at the microscope. The database (Cenozoic Antarctic DiatomWare) is displayed via a custom software program (BugCam) written in Visual Basic for use on PCs running Windows 95 or later operating systems. BugCam is a flexible image display program that utilizes an intuitive thumbnail “tree” structure for navigation through the database. The data are stored on Micrsosoft EXCEL spread sheets, hence no separate relational database program is necessary to run the package

Generation of the first BAC-based physical map of the common carp genome

<p>Abstract</p> <p>Background</p> <p>Common carp (<it>Cyprinus carpio</it>), a member of Cyprinidae, is the third most important aquaculture species in the world with an annual global production of 3.4 million metric tons, accounting for nearly 14% of the all freshwater aquaculture production in the world. Apparently genomic resources are needed for this species in order to study its performance and production traits. In spite of much progress, no physical maps have been available for common carp. The objective of this project was to generate a BAC-based physical map using fluorescent restriction fingerprinting.</p> <p>Result</p> <p>The first generation of common carp physical map was constructed using four- color High Information Content Fingerprinting (HICF). A total of 72,158 BAC clones were analyzed that generated 67,493 valid fingerprints (5.5 × genome coverage). These BAC clones were assembled into 3,696 contigs with the average length of 476 kb and a N50 length of 688 kb, representing approximately 1.76 Gb of the common carp genome. The largest contig contained 171 BAC clones with the physical length of 3.12 Mb. There are 761 contigs longer than the N50, and these contigs should be the most useful resource for future integrations with linkage map and whole genome sequence assembly. The common carp physical map is available at <url>http://genomics.cafs.ac.cn/fpc/WebAGCoL/Carp/WebFPC/</url>.</p> <p>Conclusion</p> <p>The reported common carp physical map is the first physical map of the common carp genome. It should be a valuable genome resource facilitating whole genome sequence assembly and characterization of position-based genes important for aquaculture traits.</p

A large West Antarctic Ice Sheet explains early Neogene sea-level amplitude

Early to Middle Miocene sea-level oscillations of approximately 40-60 m estimated from far-field records1-3 are interpreted to reflect the loss of virtually all East Antarctic ice during peak warmth2. This contrasts with ice-sheet model experiments suggesting most terrestrial ice in East Antarctica was retained even during the warmest intervals of the Middle Miocene4,5. Data and model outputs can be reconciled if a large West Antarctic Ice Sheet (WAIS) existed and expanded across most of the outer continental shelf during the Early Miocene, accounting for maximum ice-sheet volumes. Here we provide the earliest geological evidence proving large WAIS expansions occurred during the Early Miocene (~17.72-17.40 Ma). Geochemical and petrographic data show glacimarine sediments recovered at International Ocean Discovery Program (IODP) Site U1521 in the central Ross Sea derive from West Antarctica, requiring the presence of a WAIS covering most of the Ross Sea continental shelf. Seismic, lithological and palynological data reveal the intermittent proximity of grounded ice to Site U1521. The erosion rate calculated from this sediment package greatly exceeds the long-term mean, implying rapid erosion of West Antarctica. This interval therefore captures a key step in the genesis of a marine-based WAIS and a tipping point in Antarctic ice-sheet evolution