New Method of Measuring Permanent Viscosity Loss of Polymer-Containing Lubricants

An ultrahigh shear rate viscometer (USV) was used to measure the viscosity of polymer solutions. It was found that some polymer solutions in base oil, including those used as engine oil viscosity modifiers, show permanent viscosity loss when subjected to very high shear rates above 10⁶ s^?1. The USV was modified to automatically carry out a series of viscosity measurements on the same test lubricant sample. This enabled the accumulation of permanent viscosity loss to be measured over successive strain cycles.

As expected, permanent viscosity loss increased with both strain rate and molecular weight. When carried out at 5 × 10⁶ s^?1 and 100°C, the test was more severe than the Kurt Orbahn test because samples of lubricants subjected to the latter underwent further shear thinning in the USV.

The USV test appears to be a rapid and convenient way to quantify the permanent viscosity loss of polymer-containing lubricants for engine use, and a protocol to assess permanent viscosity loss (PVL) and permanent shear stability index (PSSI) based on viscosity measurements at 10⁶ s^?1 before and after shear thinning is outlined.

The study also shows that it is important to take into account possible permanent viscosity loss when measuring the viscosity of polymer solutions in very high shear rate viscometers such as the USV. This can be done by minimizing the amount of shear to which the lubricant is subjected or by taking successive measurements and subtracting the permanent viscosity loss taking place in each of the first few strain rate cycles.     

Adhesion-Induced Interactions between Micron-Sized Zirconia or Carbon Spheres and Melamine-Cross-Linked Polyester Surfaces

The thermodynamic work of adhesion between micron-sized zirconia or carbon spheres and polyester-melamine surfaces was determined using the Johnson-Kendall-Roberts (JKR) relationship, after first validating the JKR approach for this system. The calculated works of adhesion for both zirconia and carbon were similar for any given substrate composition and were found to be approximately 35 mJ/m² at low melamine concentrations, close to theoretical predictions. The apparent work of adhesion decreased with increasing melamine concentration, most likely due to the presence of a glassy melamine-rich surface layer, which is not representative of the bulk. The value found for low melamine concentration was assumed to be a true value for cocondensed polyester-melamine, and this was used to estimate surface modulus and the amount of excess melamine in the surface as a function of bulk composition.     

Characterisation of acid mine drainage in a high rainfall mountain environment, New Zealand

The Stockton coal mine lies at 700-1100 m above sea level in a mountainous orographic precipitation zone on the West Coast of the South Island of New Zealand. Rainfall exceeds 6000 mm/year and arrives with frequent flood events that can deliver > 200 mm/day. Streams vary in discharges by up to two orders of magnitude over a time scale of hours. Pyritic waste rock at the mine interacts chemically with even the most intense rainfall, and almost all runoff is acidic to some degree. In the most intense rain event recorded in this study (> 10 mm/hour), dilution of acid mine drainage (AMD) occurred and pH rose from 3 to > 5 over several hours, with stream discharge at a monitoring point rising from < 0.5 to > 100 cumecs. However, most rain events of similar magnitude are less intense, longer duration, and only raise AMD pH to ~ 4 with similar high discharges. Results presented here for Stockton confirm that it is the intensity of rain events on the hourly scale, rather than the total amount of rainwater delivered to the site, that governs the amount and composition of AMD generated during flood events. Stream discharge loads of dissolved iron and aluminium range from ~ 20 to 1000 kg/hour. Dissolved sulfate and acidity loads are typically ~ 500 kg/hour but can exceed 20 tonnes/hour in rain events.First flush effects observable elsewhere around the world involving peak metal loads following dry periods or seasonal changes are not obvious at Stockton due to the high and variable rainfall environment. Dissolved Fe concentrations may be limited in runoff waters by precipitation of jarosite and schwertmannite, especially when rainfall is sufficiently intense to raise pH to 4 or higher. These minerals are widespread in the exposed waste rock on site. Likewise, precipitation of alunite may occur as pH rises in rain events, but no field evidence for this has been observed.     

Ruins and Revival: Paris in the Aftermath of the Second World War

Although many devastated European cities have been studied, the bombing and reconstruction of key industrial sites and certain suburban residential zones in greater Paris have received little scholarly attention. Using archival sources, this article explores both destruction and reconstruction, and traces how homeless families shared apartments or endured years of 'temporary' accommodation in huts and other shelters. Post-war economic planning in France privileged the restoration of industrial and commercial sites; rebuilding of housing by the state, by housing co-operatives and by individual property owners received less support and progressed far more slowly. Today, the visual legacy of reconstruction is easily confused with that of completely new post-war apartments; however its origin, if not its architecture, is distinctively different and merits recognition in its own right.     

The existential psychotherapy of phobias.

Describes the existential psychotherapy of phobic patients. The failure of much contemporary psychotherapy is based in an insufficient psychology of the phobic process. The phobic mechanism is intentional and derives from the focused awareness patients have of their own vulnerability in a certain situation and an attempt to preempt the situation by the creation of a mythology that permits a degree of control and a concomitant loss of awareness of the experience to be avoided. The psychotherapy of phobic patients is comprised of 5 stages. Patients must be assured as to the correctness, integrity, and limited effect of their anxiety. They then come to see the intentionality and integrity in their phobic structures and subsequently recognize their power over the process should they be willing to restructure their way of being in the world. The 4th step occurs with the reclamation of the specific knowledge and feelings that patients have attempted to render unconscious. The final stage is the constant attentiveness to the interpersonal process and the suffering and survival of the primary difficulty. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Productivity Through Automation

Productivity improvements in systems development can be made through the adoption of computer-aided software engineering (CASE), data design, and prototyping tools. How much these tools contribute to increased productivity in systems design, however, relies mostly on careful evaluation and selection of these tools as well as an evaluation of their impact on the designer or analyst who will be using the tool and on the development methodology itself.     

Why CASE Is Not a Cure for Testing

Although systems development testing is a critical ingredient in the successful design of a system, it is often regarded as an unnecessary effort needed only to correct errors on poorly designed (or unlucky) systems. The author explains why testing is, in fact, the one constant element of systems development that must be performed more often and why computer-aided software engineering (CASE) does not eliminate the need for testing.     

Multiple Classification Analysis for Arbitrary Experimental Arrangements

Usually an experiment is designed so as to be as balanced as possible which, among other things, simplifies the analysis of the results. However, if an appreciable number of planned observations is missing, if the data are from a survey, or if historical data are being screened, the arrangement of observations may be quite disorganized. This paper presents a simple method for finding a set of independent normal equations when the arrangement of observations is completely arbitrary. From these normal equations and their solution one can determine estimates of the parameters of the general linear model being fitted to the data, which linear functions of parameters are estimable, which hypotheses are testable, sums of squares for testable hypotheses, and point estimates and confidence intervals for estimable functions. A numerical example is included to illustrate the method.     

Local temperature determination of optically excited nanoparticles and nanodots

A thin film of Al(0.94)Ga(0.06)N embedded with Er(3+) ions is used as an optical temperature sensor to image the temperature profile around optically excited gold nanostructures of 40 nm gold nanoparticles and lithographically prepared gold nanodots. The sensor is calibrated to give the local temperature of a hot nanostructure by comparing the measured temperature change of a spherical 40 nm gold NP to the theoretical temperature change calculated from the absorption cross section. The calibration allows us to measure the temperature where a lithographically prepared gold nanodot melts, in agreement with the bulk melting point of gold, and the size of the nanodot, in agreement with SEM and AFM results. Also, we measure an enhancement in the Er(3+) photoluminescence due to an interaction of the NP and Er(3+). We use this enhancement to determine the laser intensity that melts the NP and find that there is a positive discontinuous temperature of 833 K. We use this discontinuous temperature to obtain an interface conductance of ～10 MW/m(2)-K for the gold NP on our thermal sensor surface.