Pressure-viscosity measurements for several lubricants to 5.5 x 10 to the 8th power Newtons per square meter (8 x 10 to the 4th psi) and 149 C (300 F)

A capillary viscometer was used to measure viscosity as a function of pressure, temperature, and shear stress for a number of lubricants. The conditions under which the measurements were made are specified. The results obtained for each material are analyzed. It was determined that all pressure-viscosity coefficients decreased with increasing temperature. Data from other techniques such as optical elastohydrodynamics, oscillating crystal, and low shear capillary viscometry were compared with the results obtained

Ferrographic analysis of wear particles from sliding elastohydrodynamic experiments

The Ferrograph was used to analyze wear debris generated in a sliding elastohydrodynamic contact. The amount of wear debris correlates well with the ratio of film thickness to composite surface roughness (A ratio). The general wear level parameter and the wear severity index yielded similar correlations with average A ratios. Essentially all the generated wear particles were of the normal rubbing wear type. The Ferrograph was more sensitive in detecting the wear debris than was the commonly used emission spectrograph

Ferrographic analysis of wear debris generated in a sliding elastohydrodynamic contact

The ferrograph was used to analyze wear debris generated in a sliding elastohydrodynamic contact. The amount of wear debris correlates well with the ratio of film thickness to composite surface roughness. Essentially all of the generated wear particles were of the normal rubbing wear type

Good Timing for Computational Models of Narrative Discourse

The temporal order in which story events are presented in discourse can greatly impact how readers experience narrative; however, it remains unclear how narrative systems can leverage temporal order to affect comprehension and experience. We define structural properties of discourse which provide a basis for computational narratologists to reason about good timing, such as when readers learn about event relationships

Addressing Common Concerns about Online Student Ratings of Instruction: A Research-Informed Approach

Concerns over the usefulness and validity of student ratings of instruction (SRI) have continued to grow with online processes. This paper presents seven common and persistent concerns identified and tested during the development and implementation of a revised SRI policy at a Canadian research-intensive university. These concerns include bias due to insufficient sample size, student academic performance, polarized student responses, disciplinary differences, class size, punishment of rigorous instructor standards, and timing of final exams. We analyzed SRI responses from two mandatory Likert scale questions related to the course and instructor, both of which were consistent over time and across all academic units at our institution. The results show that overall participation in online SRIs is representative of the student body, with academically stronger students responding at a higher rate, and the SRIs, themselves, providing evidence that may moderate worries about the concerns.   Avec les processus électroniques, les inquiétudes quant à l’utilité et à la validité des évaluations de l’enseignement par les étudiants (EEE) ne cessent de croître. Le présent document révèle sept problèmes communs et constants concernant l’utilité et la validité des évaluations électroniques de l’enseignement par les étudiants (EEE) en ligne qui ont été identifiés et testés dans une université canadienne centrée sur la recherche. Parmi ces problèmes, on compte une déformation des résultats attribuable à un échantillon de taille insuffisante, une faible performance scolaire des étudiants, une polarisation des réponses des étudiants, des différences disciplinaires, des classes de taille inégale, une perception négative face aux attentes élevées de certains chargés de cours et l’horaire des examens finaux. Nous avons analysé les réponses à deux questions obligatoires, selon une échelle de Likert, et liées au cours et à son chargé de cours. Les deux questions ont conservé leur cohérence au fil du temps et au sein de l’ensemble des unités d’enseignement de notre institution. Les résultats démontrent que la participation à l’EEE en ligne est généralement représentative du corps étudiant, bien que le taux de participation des étudiants plus performants au niveau académique s’est révélé plus élevé. Cela nous fournit un argument important pour répondre aux inquiétudes souvent émises au sujet des problèmes liés à l’EEE

Substantial Doubt Remains about the Efficacy of Anti-Amyloid Antibodies

Alzheimer's disease (AD) is a prevalent, progressive, and ultimately fatal neurodegenerative disorder that is defined pathologically by the accumulation of amyloid plaques and tau neurofibrillary tangles in the brain. There remains an unmet need for therapies that can halt or slow the course of AD. To address this need, the FDA has provided a mechanism, under its Accelerated Approval pathway, for potential therapeutics to be approved based in part on their ability to reduce brain amyloid. Through this pathway, two monoclonal anti-amyloid antibodies, aducanumab and lecanemab, have been approved for clinical use. More recently, another amyloid-lowering antibody, donanemab, generated a statistically significant outcome in a phase 3 clinical trial and will shortly come under FDA review. While these monoclonal antibodies are not yet routinely used in clinical practice, the series of recent positive clinical trials has fostered enthusiasm amongst some AD experts. Here, we discuss three key limitations regarding recent anti-amyloid clinical trials: (1) there is little to no evidence that amyloid reduction correlates with clinical outcome, (2) the reported efficacy of anti-amyloid therapies may be partly, or wholly, explained by functional unblinding, and (3) donanemab in its phase 3 trial had no effect on tau burden, the pathological hallmark more closely related to cognition. Taken together, these observations call into question the efficacy of anti-amyloid therapies.Comment: 11 pages, 2 figures; Update 11/18/2023: Added subheadings to manuscript to improve readability, added a new data point to Figure 1A and Figure 2 for the recently published A4 clinical tria

Reference Distorted Prices

I show that when consumers (mis)perceive prices relative to reference prices, budgets turn out to be soft, prices tend to be lower and the average quality of goods sold decreases. These observations provide explanations for decentralized purchase decisions, for people being happy with a purchase even when they have paid their evaluation, and for why trade might affect high quality local firms 'unfairly'

Investigations of lubricant rheology as applied to elastohydrodynamic lubrication

Traction prediction in sliding elastohydrodynamic (EHD) contacts was examined along with an elastohydrodynamic lubrication simulation of the effects of load and speed on temperatures in the EHD contact. An existing shear stress theory and lubricant rheological model were studied and evaluated by applying them to traction prediction. Results obtained using measured film thickness and surface temperature data, were compared with measured traction values. The infrared technique for measuring temperatures in an EHD contact was further developed and ball surface and fluid temperatures are reported for sliding speeds of 0.35 to 5.08 m/s at 0.52 to 2.03 GN/sq m maximum pressure and surface roughnesses of .011 to .381 micrometers c.1.a. The relationship between asperity interaction, as measured by relocation surface profilimetry and high frequency temperature measurements, and the ratio of film thickness to surface roughness was also studied