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

Silicon micromachined mass filter for a low power, low cost quadrupole mass spectrometer

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Replicators, lineages, and interactors

AbstractThe target article argues that whole groups can act as interactors in an evolutionary process. We believe that Smaldino's discussion would be advanced by a more thorough analysis of the appropriate replicators and lineages for this model. We show that cultural evolution is necessarily a separate process from cultural group selection, and we also illustrate that the two processes may influence each other as demonstrated by an agent-based model of communicating food-processing skills.</jats:p

Electronic transport and vibrational modes in the smallest molecular bridge: H2 in Pt nanocontacts

We present a state-of-the-art first-principles analysis of electronic transport in a Pt nanocontact in the presence of H2 which has been recently reported by Smit et al. in Nature 419, 906 (2002). Our results indicate that at the last stages of the breaking of the Pt nanocontact two basic forms of bridge involving H can appear. Our claim is, in contrast to Smit et al.'s, that the main conductance histogram peak at G approx 2e^2/h is not due to molecular H2, but to a complex Pt2H2 where the H2 molecule dissociates. A first-principles vibrational analysis that compares favorably with the experimental one also supports our claim .Comment: 5 pages, 3 figure

Do actions occur inside the body?

The paper offers a critical examination of Jennifer Hornsby's view that actions are internal to the body. It focuses on three of Hornsby's central claims: (P) many actions are bodily movements (in a special sense of the word “movement”) (Q) all actions are tryings; and (R) all actions occur inside the body. It is argued, contra Hornsby, that we may accept (P) and (Q) without accepting also the implausible (R). Two arguments are first offered in favour of the thesis (Contrary-R): that no actions occur inside the body. Three of Hornsby's arguments in favour of R are then examined. It is argued that we need to make a distinction between the causes and the causings of bodily movements (in the ordinary sense of the word “movement”) and that actions ought to be identified with the latter rather than the former. This distinction is then used to show how Hornsby's arguments for (R) may be resisted

Vacuum production of OTFTs by vapour jet deposition of dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) on a lauryl acrylate functionalised dielectric surface

Roll-to-roll (R2R) production of organic transistors and circuits require patterned deposition of organic layers at high deposition rate. Here we demonstrate a vapour-jet process for the rapid deposition of the organic semiconductor dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT). The deposition rate achieved, equivalent to ~200 nm/s onto a stationary substrate, was several orders of magnitude faster than ordinary thermal evaporation. Nevertheless, transistor yield was 100% with an average mobility of 0.4 cm2/Vs in a single pass deposition onto a substrate moving at 0.15 m/min. We also demonstrate a vacuum, high rate R2R-compatible process for surfacefunctionalising a gate dielectric layer with lauryl acrylate which enabled an all-vacuum route to the fabrication of a five-stage ring oscillator

Improved Nearside-Farside Decomposition of Elastic Scattering Amplitudes

A simple technique is described, that provides improved nearside-farside (NF) decompositions of elastic scattering amplitudes. The technique, involving the resummation of a Legendre partial wave series, reduces the importance of unphysical contributions to NF subamplitudes, which can arise in more conventional NF decompositions. Applications are made to a strong absorption model and to a $^{16}$O + $^{12}$C optical potential at $E_{\text{lab}} = 132$ MeV.Comment: 5 pages, 2 figure

Stable organic static random access memory from a roll-to-roll compatible vacuum evaporation process

An organic Static Random Access Memory (SRAM) based on p-type, six-transistor cells is demonstrated. The bottom-gate top-contact thin film transistors composing the memory were fabricated on flexible polyethylene naphthalate substrates. All metallization layers and the p-type semiconductor dinaphtho[2,3-b:2',3'-f] thieno[3,2-b]thiophene were deposited by thermal evaporation. The gate dielectric was deposited in a vacuum roll-to-roll environment at a web speed of 25 m/min by flash-evaporation and subsequent plasma polymerisation of tripropyleneglycol diacrylate (TPGDA). Buffering the TPGDA with a polystyrene layer yields hysteresis-free transistor characteristics with turn-on voltage close to zero. The static transfer characteristic of diode-connected load inverters were also hysteresis-free with maximum gain &gt;2 and noise margin ∼2.5 V. When incorporated into SRAM cells the time-constant for writing data into individual SRAM cells was less than 0.4 ms. Little change occurred in the magnitude of the stored voltages, when the SRAM was powered continuously from a −40 V rail for over 27 h testifying to the electrical stability of the threshold voltage of the individual transistors. Unencapsulated SRAM cells measured two months after fabrication showed no significant degradation after storage in a clear plastic container in normal laboratory ambient

Organic Digital Logic and Analog Circuits Fabricated in a Roll-to-Roll Compatible Vacuum-Evaporation Process

We report the fabrication of a range of organic circuits produced by a high-yielding, vacuum-based process compatible with roll-to-roll production. The circuits include inverters, NAND and NOR logic gates, a simple memory element (set-reset latch), and a modified Wilson current mirror circuit. The measured circuit responses are presented together with simulated responses based on a previously reported transistor model of organic transistors produced using our fabrication process. Circuit simulations replicated all the key features of the experimentally observed circuit performance. The logic gates were capable of operating at frequencies in excess of 1 kHz while the current mirror circuit produced currents up to 18 μA