Lubricant degradation, transport and the effect of extended oil drain intervals on piston assembly tribology

There are ever increasing demands on lubricant manufacturers to meet governmental legislation and customer needs by improving fuel economy, engine durability and exhaust system compatibility as shown by the introduction of GF4 and move towards GF5 specification oils. This has created an ever increasing need to understand how oil degrades in an engine and how this degraded oil affects piston assembly tribology. This review conference paper will give an overview of a collaborative project that has been undertaken to further enhance the understanding of how lubricant degrades in an operating engine, its transport through the engine and effect upon piston assembly tribology

Extraction and tribological investigation of top piston ring zone oil from a gasoline engine

With tightening emission regulations, increased expected fuel economy, and longer drain intervals impacting on lubricant formulation, greater understanding of how oil degrades in an automotive engine is becoming ever more important. Equally significant is the effect that this degraded lubricant has on the tribological operation of the engine, particularly its overall internal friction and component wear. In a previous paper, four tests to degrade oil in a single cylinder engine were reported [1]. These tests were set up such that the lubricating oil was degraded in the ring pack before returning to the sump, where it was sampled and chemical and rheological analysis undertaken. This paper reports the extension of this work using the same Hydra engine and describes how oil has additionally been extracted from the rear of the top piston ring during engine operation. This extracted oil has then been subjected to similar analysis as the sump oil samples in the previous tests, along with additional analysis to look at the tribological properties of the oil using tribometers. The results clearly show significant differences in the rheological, tribological, and chemical properties of the fresh oil and used sump oil samples when compared with the top ring zone (TRZ) oil samples, particularly the effect of load on the levels of volatiles present in the TRZ samples and their effect on traction and friction coefficient values during tribological testing

The Presence of Cross Education within the Body- An Evaluation of Contralateral Grip Strength

Please enjoy Volume 5, Issue 1 of the JSMAHS. In this issue you will find Professional and under graduate research abstracts, case reports, and critically appraised topics. Thank you for viewing this 5th Annual OATA Special Edition

The Role of Helicity in Magnetic Reconnection: 3D Numerical Simulations

We demonstrate that conservation of global helicity plays only a minor role in determining the nature and consequences of magnetic reconnection in the solar atmosphere. First, we show that observations of the solar coronal magnetic field are in direct conflict with Taylor's theory. Next, we present results from three-dimensional MHD simulations of the shearing of bipolar and multi-polar coronal magnetic fields by photospheric footpoint motions, and discuss the implications of these results for Taylor's theory and for models of solar activity. The key conclusion of this work is that significant magnetic reconnection occurs only at very specific locations and, hence, the Sun's magnetic field cannot relax completely down to the minimum energy state predicted by conservation of global helicity.Comment: AGU LaTeX manuscript, 17 pages, 2 b-w figures, 4 color plate

Seasonality of microbial genetic functions in the Arctic Ocean revealed by autonomous sampling

The functional diversity of microbes along the seasonal extremes in the Arctic Ocean including the Polar Night are virtually unknown. Here, using PacBio long-read metagenomes derived from automated samplers over an annual cycle, we elucidate functional microbial seasonality in the Fram Strait in the context of a high-resolution amplicon time-series. In the ice-free West Spitsbergen Current, the transition from the phototrophy-dominated spring and summer ecosystem states to the dark winter was evident in bacterial genomes. Proteorhodopsin- and DMSP-utilizing genes peaked in late summer, marking a transition phase. Winter mixing of the water column covaried with microbial taxa encoding ammonia- and urea-metabolizing genes, with probable implications for nitrogen recycling and the following phytoplankton bloom. In the ice-covered East Greenland Current, functional diversity varied with the extent of ice cover and polar water masses. During intermittent low-ice conditions in winter, the metagenomic repertoire resembled that during summer, indicating rapidly (i.e. within weeks) shifting ecosystem states with ice cover. Overall, we provide a baseline to understand ecological and biogeochemical processes in a region severely affected by climate change, with implications for the present and future Arctic Ocean

Formation and Primary Heating of The Solar Corona - Theory and Simulation

An integrated Magneto-Fluid model, that accords full treatment to the Velocity fields associated with the directed plasma motion, is developed to investigate the dynamics of coronal structures. It is suggested that the interaction of the fluid and the magnetic aspects of plasma may be a crucial element in creating so much diversity in the solar atmosphere. It is shown that the structures which comprise the solar corona can be created by particle (plasma) flows observed near the Sun's surface - the primary heating of these structures is caused by the viscous dissipation of the flow kinetic energy.Comment: 46 pages including 7 pages of figures, Submitted to Phys.Plasma

Star-planet magnetic interaction and activity in late-type stars with close-in planets

Late-type stars interact with their close-in planets through their coronal magnetic fields. We introduce a theory for the interaction between the stellar and planetary fields focussing on the processes that release magnetic energy in the stellar coronae. We consider the energy dissipated by the reconnection between the stellar and planetary magnetic fields as well as that made available by the modulation of the magnetic helicity of the coronal field produced by the orbital motion of the planet. We estimate the powers released by both processes in the case of axisymmetric and non-axisymmetric, linear and non-linear force-free coronal fields finding that they scale as v_r (B_s)^(4/3) (B_p)^(2/3) (R_p)^2, where v_r is the relative velocity between the stellar and planetary fields, B_s the mean stellar surface field, B_p the planetary field at the poles, and R_p the radius of the planet. A chromospheric hot spot or a flaring activity phased to the orbital motion of the planet are found only when the stellar field is axisymmetric. In the case of a non-axisymmetric field, the time modulation of the energy release is multiperiodic and can be easily confused with the intrinsic stellar variability. We apply our theory to the systems with some reported evidence of star-planet magnetic interaction finding a dissipated power at least one order of magnitude smaller than that emitted by the chromospheric hot spots. The phase lags between the planets and the hot spots are reproduced by our models in all the cases except for upsilon And. In conclusion, the chromospheric hot spots rotating in phase with the planets cannot be explained by the energy dissipation produced by the interaction between stellar and planetary fields as considered by our models and require a different mechanism.Comment: 16 pages, 3 figures, accepted by Astronomy and Astrophysic

An Analysis of Best Practices for Sustainable Events and Venues in Columbus

Course Code: ENR 4567Experience Columbus is seeking ways to make the events and conferences industry of Columbus more sustainable. Events such as conferences, conventions, and other large gatherings are the targeted space behind our research. The City of Columbus has set a progressive goal to be carbon neutral by 2050. With that goal as our guiding principle, this report details ways in which the events industry can help reach that goal and implement sustainable practices. We analyzed three established frameworks of sustainability and used four case study examples to explore the many innovative ways event organizers can host sustainable events and conferences. We also met the Professional Convention Management Association (PCMA) to gain insight on how their team organizes sustainable events and learn more about their framework of evaluation. Using all of the research and information gathered from in depth literature reviews, we brought together many ideas and practices from the various frameworks and case studies into a synthesized list of six categories of best practices. Our six categories are energy, supply chain, waste reduction, transportation, water usage, and infrastructure. Detailed under each category are what we found to be the most effective ways to reduce the carbon footprint of events and conferences. This paper concludes with our recommendations on how to implement the various best practices described in the report as well as going into detail about the expected limitations and challenges of implementation.Experience ColumbusAcademic Major: Environment, Economy, Development, and Sustainabilit

The Flare-energy Distributions Generated by Kink-unstable Ensembles of Zero-net-current Coronal Loops

It has been proposed that the million degree temperature of the corona is due to the combined effect of barely-detectable energy releases, so called nanoflares, that occur throughout the solar atmosphere. Alas, the nanoflare density and brightness implied by this hypothesis means that conclusive verification is beyond present observational abilities. Nevertheless, we investigate the plausibility of the nanoflare hypothesis by constructing a magnetohydrodynamic (MHD) model that can derive the energy of a nanoflare from the nature of an ideal kink instability. The set of energy-releasing instabilities is captured by an instability threshold for linear kink modes. Each point on the threshold is associated with a unique energy release and so we can predict a distribution of nanoflare energies. When the linear instability threshold is crossed, the instability enters a nonlinear phase as it is driven by current sheet reconnection. As the ensuing flare erupts and declines, the field transitions to a lower energy state, which is modelled by relaxation theory, i.e., helicity is conserved and the ratio of current to field becomes invariant within the loop. We apply the model so that all the loops within an ensemble achieve instability followed by energy-releasing relaxation. The result is a nanoflare energy distribution. Furthermore, we produce different distributions by varying the loop aspect ratio, the nature of the path to instability taken by each loop and also the level of radial expansion that may accompany loop relaxation. The heating rate obtained is just sufficient for coronal heating. In addition, we also show that kink instability cannot be associated with a critical magnetic twist value for every point along the instability threshold

A Nanoflare Distribution Generated by Repeated Relaxations Triggered by Kink Instability

Context: It is thought likely that vast numbers of nanoflares are responsible for the corona having a temperature of millions of degrees. Current observational technologies lack the resolving power to confirm the nanoflare hypothesis. An alternative approach is to construct a magnetohydrodynamic coronal loop model that has the ability to predict nanoflare energy distributions. Aims: This paper presents the initial results generated by such a model. It predicts heating events with a range of sizes, depending on where the instability threshold for linear kink modes is encountered. The aims are to calculate the distribution of event energies and to investigate whether kink instability can be predicted from a single parameter. Methods: The loop is represented as a straight line-tied cylinder. The twisting caused by random photospheric motions is captured by two parameters, representing the ratio of current density to field strength for specific regions of the loop. Dissipation of the loop's magnetic energy begins during the nonlinear stage of the instability, which develops as a consequence of current sheet reconnection. After flaring, the loop evolves to the state of lowest energy where, in accordance with relaxation theory, the ratio of current to field is constant throughout the loop and helicity is conserved. Results: The results suggest that instability cannot be predicted by any simple twist-derived property reaching a critical value. The model is applied such that the loop undergoes repeated episodes of instability followed by energy-releasing relaxation. Hence, an energy distribution of the nanoflares produced is collated. Conclusions: The final energy distribution features two nanoflare populations that follow different power laws. The power law index for the higher energy population is more than sufficient for coronal heating.Comment: 13 pages, 18 figure