Conversion of low BMEP 4-cylinder to high BMEP 2-cylinder large bore natural gas engine

Includes bibliographical references.2016 Summer.There are more than 6,000 integral compressor engines in use on US natural gas pipelines, operating 24 hours a day, 365 days a year. Many of these engines have operated continuously for more than 50 years, with little to no modifications. Due to recent emission regulations at the local, state and federal levels much of the aging infrastructure requires retrofit technology to remain within compliance. The Engines and Energy Conversion Laboratory was founded to test these retrofit technologies on its large bore engine testbed (LBET). The LBET is a low brake mean effective pressure (BMEP) Cooper Bessemer GMVTF-4. Newer GMV models, constructed in 1980’s, utilize turbocharging to increase the output power, achieving BMEP’s nearly double that of the LBET. To expand the lab’s testing capability and to reduce the LBET’s running cost: material testing, in-depth modeling, and on engine testing was completed to evaluate the feasibility of uprating the LBET to a high BMEP two cylinder engine. Due to the LBET’s age, the crankcase material properties were not known. Material samples were removed from engine to conduct an in-depth material analysis. It was found that the crankcase was cast out of a specific grade of gray iron, class 25 meehanite. A complete three dimensional model of the LBET’s crankcase and power cylinders was created. Using historical engine data, the force inputs were created for a finite element analysis model of the LBET, to determine the regions of high stress. The areas of high stress were instrumented with strain gauges to iterate and validate the model’s findings. Several test cases were run at the high and intermediate BMEP engine conditions. The model found, at high BMEP conditions the LBET would operate at the fatigue limit of the class 25 meehanite, operating with no factor of safety but the intermediate case were deemed acceptable

Network Poetics: Studies in Early Modern Literary Collaboration

Literature scholars often consider the seventeenth century to be the period in which the role of the individual author as we know it today was consolidated, strengthened, or even invented. Scholars of collaboration, most notably Jeffrey Masten in his book Textual Intercourse, tend to treat the phenomenon of joint literary work as limited to coauthorship and either to specific genres (usually drama) or specific periods in time (usually 1590 to 1620). In this model, collaborative environments give way to authorial ones, particularly in Restoration England as the position of the professional author was strengthened by changes in publishing practices. However scholars of book history from Donald McKenzie to Harold Love to Lisa Jardine have shown that exchange, association, and relationality were the rule rather than the exception throughout the period. I extend these principles outside print and manuscript practices as I show that the many social communities an author engages with affect the creative work that they produce, and I make a case that the techniques of network analysis provide an important perspective on the collectivity of literary production. In so doing I argue that early modern literary production is driven by sets of relationships which give character to literary works, and I discuss social relations and modes of collaboration that have identifiable and distinct effects on literary forms in different genres and historical periods

Transport of multiple tracers in variably saturated humid region structured soils and semi-arid region laminated sediments

The processes governing physical nonequilibrium (PNE)—coupled preferential flow and matrix diffusion—are diverse between humid and semi-arid regions, and are directly related to climate and rock/sediment type, and indirectly related to subsequent soil profile development. The fate and transport of contaminants in these variably saturated undisturbed media is largely a function of the influence of PNE processes. Large cores of laminated silts and sands were collected from the US Department of Energy Pacific Northwest National Laboratory (PNNL) in semi-arid south central Washington. Additional cores of weathered, fractured interbedded limestone and shale saprolite were collected from the Oak Ridge National Laboratory (ORNL) in humid eastern Tennessee. PNNL cores were collected parallel (FBP) and perpendicular (FXB) to bedding, and the ORNL core was 30° to bedding. Saturated and unsaturated transport experiments were performed using multiple nonreactive tracers that had different diffusion coefficients (Br−, PFBA, and PIPES), in order to identify the influence of PNE on the fate and transport of solutes. In the ORNL structured saprolite, solute transport was governed by coupled preferential flow and matrix diffusion, as evidenced by tracer separation and highly asymmetric breakthrough curves (BTC). BTCs became more symmetric as preferential flowpaths became inactive during drainage. Tracer separation persisted during unsaturated flow suggesting the continued importance of nonequilibrium mass transfer between flowpaths and the immobile water that was held in the soil matrix. No evidence of PNE was observed under near-saturated conditions in the semi-arid region (PNNL) laminated silts and sands. Unsaturated flow in cores with discontinuous layering resulted in preferential flow and the development of perched, immobile water as evidenced by early breakthrough and separation of tracers. Conversely, transport parallel to laterally continuous beds did not result in preferential flow, the development of perched water, or tracer separation regardless of water content. These observations suggested that desaturation had two effects: (1) grain size variations between individual beds resulted in different antecedent water contents, and (2) the exchange of water and solutes between individual sedimentary beds was subsequently inhibited. Under unsaturated conditions, these effects may promote either stable lateral flow, or unstable vertical finger flow coupled with the development of perched, immobile water

High Reliability Pistons for Reciprocating Compressors with Validated Performance Modelling

LecturePiston ring leakage on reciprocating compressors is predictable due to defined leakage paths at the end gaps of piston rings. A new engineering approach quantifies the slippage and determines the dynamic pressure difference on each ring. With this approach the expected discharge gas temperature increase, expected capacity losses and the risks of rider bands activation due to piston ring slippage can be quantified. The piston design and ring styles can be iterated to find an optimized piston layout for a given application. 30% of the reciprocating compressors in the process gas industry show high sensitivity to piston ring leakage and subsequent performance related issues. This paper suggests quantifying piston performance as a standard when evaluating compressor reliability and efficiency. The industry managed to reduce compressor valve related problems due to more sophisticated modelling tools and smart design changes on valves. It is time to go that next step on pistons

The 40 and 50 GHz propagation experiments at the Rutherford Appleton Laboratory, UK, using the ITALSAT beacons

This paper describes the current experimental program and future plans for the reception of transmissions from the 18.7, 39.6, and 49.5 GHz beacons from the ITALSAT satellite by the Radio Communications Research Unit at Rutherford Appleton Laboratory, UK. The Radio Communications Research Unit, which has had considerable experience in developing experimental millimetric equipment for propagation studies, has initiated the development of a single-channel receiver and a triple-channel receiver to measure propagation effects at 49.5 GHz and 39.6 GHz respectively. The initial location of the receivers will be at Chilbolton, Hampshire, UK

Spin decay and quantum parallelism

We study the time evolution of a single spin coupled inhomogeneously to a spin environment. Such a system is realized by a single electron spin bound in a semiconductor nanostructure and interacting with surrounding nuclear spins. We find striking dependencies on the type of the initial state of the nuclear spin system. Simple product states show a profoundly different behavior than randomly correlated states whose time evolution provides an illustrative example of quantum parallelism and entanglement in a decoherence phenomenon.Comment: 6 pages, 4 figures included, version to appear in Phys. Rev.

Rebirth of a Radio Show Website Leads to New Roles and New Publicity for Librarians

Background: Health Sciences librarians worked with producers of YOUR HEALTH® Radio, a weekly consumer health radio show, to create a new, interactive blog/website providing consumer health information and incorporating social media. Librarians incorporate searching and indexing features, and provide links to high-­‐quality consumer health information on show topics. Purpose: The physician hosts, clinicians in the UNC Department of Family Medicine, recently requested that the librarians develop a way to share their role and contributions with the show’s audience