Quantifying oil filtration effects on bearing life

Rolling-element bearing life is influenced by the number, size, and material properties of particles entering the Hertzian contact of the rolling element and raceway. In general, rolling-element bearing life increases with increasing level of oil filtration. Based upon test results, two equations are presented which allow for the adjustment of bearing L(sub 10) or catalog life based upon oil filter rating. It is recommended that where no oil filtration is used catalog life be reduced by 50 percent

RECREATIONAL SWIMMING BENEFITS OF NEW HAMPSHIRE LAKE WATER QUALITY POLICIES: AN APPLICATION OF A REPEATED DISCRETE CHOICE MODEL

Water pollution control policies generally direct sources (i.e., industry, agriculture) to reduce loadings of certain pollutants. Thus, evaluating the relative net recreation benefits of policies to improve water quality requires establishing a linkage between the sources, the resultant water quality degradation at the affected water bodies, and, ultimately, the effect on recreation behavior. This linkage is rarely present in the empirical literature which is, thus, deficient for water pollution control policy assessment purposes. In this paper, we estimate the relative recreational swimming benefits that may result from controlling point and nonpoint sources of pollution, respectively, in New Hampshire's lakes. We use a repeated discrete choice framework to model swimming behavior as a function of each lake's level of eutrophication, bacteria, and oil and grease. For each pollutant, at each affected lake, we identify which source is responsible for the pollution, and we conduct scenarios controlling each pollution source independently, and then, taken together. Seasonal benefit estimates are presented for each scenario. Coupled with information on the most cost effective means of generating the scenarios, these estimates provide a useful starting point for a quantitative assessment of the net recreation benefits of policies to improve the quality of New Hampshire lakes.Environmental Economics and Policy,

Effects of Ultra-Clean and centrifugal filtration on rolling-element bearing life

Fatigue tests were conducted on groups of 65-millimeter bore diameter deep-groove ball bearings in a MIL-L-23699 lubricant under two levels of filtration. In one test series, the oil cleanliness was maintained at an exceptionally high level (better than a class "000" per NAS 1638) with a 3 micron absolute barrier filter. These tests were intended to determine the "upper limit" in bearing life under the strictest possible lubricant cleanliness conditions. In the tests using a centrifugal oil filter, contaminants of the type found in aircraft engine filters were injected into the filters' supply line at 125 milligrams per bearing-hour. "Ultra-clean" lubrication produced bearing fatigue lives that were approximately twice that obtained in previous tests with contaminated oil using 3 micron absolute filtration and approximately three times that obtained with 49 micron filtration. It was also observed that the centrifugal oil filter had approximately the same effectiveness as a 30 micron absolute filter in preventing bearing surface damage

Recalibrated Equations for Determining Effect of Oil Filtration on Rolling Bearing Life

In 1991, Needelman and Zaretsky presented a set of empirically derived equations for bearing fatigue life (adjustment) factors (LFs) as a function of oil filter ratings. These equations for life factors were incorporated into the reference book, "STLE Life Factors for Rolling Bearings." These equations were normalized (LF = 1) to a 10-micrometer filter rating at Beta(sub x) = 200 (normal cleanliness) as it was then defined. Over the past 20 years, these life factors based on oil filtration have been used in conjunction with ANSI/ABMA standards and bearing computer codes to predict rolling bearing life. Also, additional experimental studies have been made by other investigators into the relationship between rolling bearing life and the size, number, and type of particle contamination. During this time period filter ratings have also been revised and improved, and they now use particle counting calibrated to a new National Institute of Standards and Technology (NIST) reference material, NIST SRM 2806, 1997. This paper reviews the relevant bearing life studies and describes the new filter ratings. New filter ratings, Beta(sub x(c)) = 200 and Beta(sub x(c)) = 1000, are benchmarked to old filter ratings, Beta(sub x) = 200, and vice versa. Two separate sets of filter LF values were derived based on the new filter ratings for roller bearings and ball bearings, respectively. Filter LFs can be calculated for the new filter ratings

Wind Turbine Tribology

Wind power is of increasing interest in society due to its prospects as an environmentally friendly source of renewable energy. The use of wind turbines to extract electrical energy from wind can be dated back to the late-1800s, with the 12 kW windmill generator by Charles Brush, as well as the mid-1900s, with the 1250 kW Smith-Putnam wind turbine. Developments in the wind industry were encouraged by the oil crisis in 1973

“So it is… I don’t think that was racism either, but it was just a kind of ignorance.” : Providers’ Perceptions on Race, Racism and Addressing Racism through School-based Mental Health Services

Abstract Faculty: Faculty of Social Sciences Degree programme: Master’s Programme in Contemporary Societies Study track: Sociology Author: Ona Needelman Title: “So it is… I don’t think that was racism either, but it was just a kind of ignorance.” – Providers’ perceptions on race, racism and addressing racism through School-based mental health support Level: Master’s Degree Month and year: December, 2021 Number of pages: 76 Keywords: Racism, white supremacy, mental health, education, critical race theory, anti-racism, critical discourse analysis Supervisor or supervisors: Elina Paju Where deposited: University of Helsinki Additional information: Abstract: This study explores how mental health providers at schools recognize, conceptualize and address racism and its impact on persons of colour (POC) students’ mental health. The aim was to produce knowledge on what kinds of challenges “white” structures of school-based mental health present for practicing and understanding anti-racism. The main research questions were: 1) How do mental health professionals in schools view the influence racism has on mental health and well-being of POC pupils? 2) How do school mental health professionals make sense of, and deal with, issues of racism faced by POC students and which challenges do they face in doing so? 3) How do school mental health professionals conceptualize anti-racism as part of their professional roles? The main goal for this thesis was to draw attention to and heighten awareness around the new ways in which both organizations and employees must develop and approach anti-racist student welfare services in schools. Knowledge on racism and mental health from Finland produced by POC writers and activists was utilized, as academic research of this topic in Finland is limited. Academic research on racism in Finnish society and schools, and on racism’s impacts on mental health from other countries are introduced in the literature review. The main theory used throughout the research process was critical race theory (CRT), including critical whiteness studies. Eight voluntary in-depth qualitative interviews were conducted, with five school psychologists and four social workers all working in basic education in the metropolitan area. Three main discourses emerged from conducting critical discourse analysis, which I labelled as follows: Equality and tolerance, personal awareness and belonging. Key findings were that colorblind ideology perpetuates white supremacy, anti-racism mainly relies on individuals’ awareness of racism, and reactive strategies surpassed proactive anti-racist practices Based on the findings, colorblind ideology and reliance on individual awakenings make anti-racism targeting both prejudice and structural racism vulnerable. Recognizing racism challenges all adults with power in schools. Anti-racism will require more activism and collective action within organizations to commit professionals practicing in the field to address racism through their work

The Use of a Timeout Intervention With and Without Escape Extinction for Treatment of Escape-Maintained Noncompliance in a Classroom Setting

The present study investigated the effectiveness of two time-out (TO) procedures in reducing escape-maintained noncompliance of four children in a classroom setting. Participants were screened to assess that compliance with teacher-presented instructions was low and noncompliance was escape-maintained. Teachers were then trained to use two TO procedures, one without escape extinction (EE) and one with escape extinction following TO release. Two nonconcurrent multiple baseline across participants designs with a crossover element were used to compare levels of compliance across baseline, TO, and TO-EE phases. Increases in compliance were seen from baseline to the first intervention phase, and these increases were maintained in the second intervention phase regardless of the order of the phases. Small increases in compliance or decreases in variability were seen for some participants from the first to second intervention phase. Results indicate that TO with or without escape extinction may be an effective treatment for escape-maintained noncompliance. These results are discussed within the context of previous research on the use of TO with escape-maintained noncompliance

The Additive Effects of Components of an Intervention Package Targeting Compliance in Children With Hearing Impairments in a Classroom Setting

The present study investigated the sequential introduction of a compliance training package based on the Compliance Training for Children (CTC) Model developed in the School Psychology Program at The University of Southern Mississippi. Participants were three deaf students in the classroom setting who were referred by their teachers for exhibiting noncompliance. The teachers in this study were also deaf. A nonconcurrent multiple baseline across participants design was used to assess the effectiveness of Effective Instruction Delivery (EID), EID with contingent praise for compliance, and EID with contingent praise for compliance and time-out contingent on noncompliance. One participant reached 100% compliance with the introduction of EID alone. The other two participants reached 100% compliance with the introduction of EID plus contingent praise and time-out, although time-out was never implemented. Findings indicate that the use of these compliance training procedures may be applied to individuals with hearing impairments or deafness to increase compliance. Potential limi tations and directions for future research are discussed

The ecology of methane in streams and rivers: patterns, controls, and global significance

Streams and rivers can substantially modify organic carbon (OC) inputs from terrestrial landscapes, and much of this processing is the result of microbial respiration. While carbon dioxide (CO₂) is the major end‐product of ecosystem respiration, methane (CH₄) is also present in many fluvial environments even though methanogenesis typically requires anoxic conditions that may be scarce in these systems. Given recent recognition of the pervasiveness of this greenhouse gas in streams and rivers, we synthesized existing research and data to identify patterns and drivers of CH₄, knowledge gaps, and research opportunities. This included examining the history of lotic CH4 research, creating a database of concentrations and fluxes (MethDB) to generate a global‐scale estimate of fluvial CH₄ efflux, and developing a conceptual framework and using this framework to consider how human activities may modify fluvial CH₄ dynamics. Current understanding of CH₄ in streams and rivers has been strongly influenced by goals of understanding OC processing and quantifying the contribution of CH₄ to ecosystem C fluxes. Less effort has been directed towards investigating processes that dictate in situ CH₄ production and loss. CH₄ makes a meager contribution to watershed or landscape C budgets, but streams and rivers are often significant CH₄ sources to the atmosphere across these same spatial extents. Most fluvial systems are supersaturated with CH₄ and we estimate an annual global emission of 26.8 Tg CH₄, equivalent to ~15‐40% of wetland and lake effluxes, respectively. Less clear is the role of CH₄ oxidation, methanogenesis, and total anaerobic respiration to whole ecosystem production and respiration. Controls on CH₄ generation and persistence can be viewed in terms of proximate controls that influence methanogenesis (organic matter, temperature, alternative electron acceptors, nutrients) and distal geomorphic and hydrologic drivers. Multiple controls combined with its extreme redox status and low solubility result in high spatial and temporal variance of CH₄ in fluvial environments, which presents a substantial challenge for understanding its larger‐scale dynamics. Further understanding of CH₄ production and consumption, anaerobic metabolism, and ecosystem energetics in streams and rivers can be achieved through more directed studies and comparison with knowledge from terrestrial, wetland, and aquatic disciplines."Support for this paper was provided by funding from the North Temperate Lakes LTER program, NSF DEB‐0822700."https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/15-102