Effect of microstructure and temperature on the erosion rates and mechanisms of modified EB PVD TBCs

Thermal barrier coatings (TBCs) have now been used in gas turbine engines for a number of decades and are now considered to be an accepted technology. As there is a constant drive to increase the turbine entry temperature, in order to increase engine efficiency, the coatings operate in increasingly hostile environments. Thus there is a constant drive to both increase the temperature capabilities of TBCs while at the same time reducing their thermal conductivities. The thermal conductivity of standard 7 wt% yttria stabilized zirconia (7YSZ) electron beam (EB) physical vapour deposited (PVD) TBCs can be reduced in two ways: the first by modification of the microstructure of the TBC and the second by addition of ternary oxides. By modifying the microstructure of the TBC such that there are more fine pores, more photon scattering centres are introduced into the coatings, which reduce the heat transfer by radiation. While ternary oxides will introduce lattice defects into the coating, which increases the phonon scattering, thus reducing the thermal conductivity via lattice vibrations. Unfortunately, both of these methods can have a negative effect on the erosion resistance of EB PVD TBCs. This paper compares the relative erosion rates of ten different EB PVD TBCs tested at 90à ° impact at room temperature and at high temperature and discusses the results in term of microstructural and temperature effects. It was found that by modifying the coating deposition, such that a low density coating with a highly â  featheredâ  microstructure formed, generally resulted in an increase in the erosion rate at room temperature. When there was a significant change between the room temperature and the high temperature erosion mechanism it was accompanied by a significant decrease in the erosion rate, while additions of dopents was found to significantly increase the erosion rate at room and high temperature. However, all the modified coatings still had a lower erosion rate than a plasma sprayed coatings. So, although, relative to a standard 7YSZ coating, the modified coatings have a lower erosion resistance, they still perform better than PS TBCs and their lower thermal conductivities could make them viable alternatives to 7YSZ for use in gas turbine en

Educational Materials and Brief Counseling Improve Diabetes Knowledge and Self-Efficacy

Purpose: The purpose of this study was to see if education and counseling of the Appalachian individual with diabetes and a family member/friend would improve knowledge of the disease and self-efficacy of the patient in regard to their diabetes care. Setting: The setting was one of eight primary care offices of Our Lady of Bellefonte Hospital, Bon Secours, located in the Ashland, Kentucky. Design: A pilot study of descriptive, comparative design was used. Subjects: Data were collected from a convenience sample of patients with type 2 diabetes (n=15) that were established at the primary care office and their family members/friends (n=15). Measurements: The Diabetes Knowledge Tests (DKT), the Diabetes Empowerment Tests (DES-SF) and the Thai Family Function Tests were used to assess the subjective variables of interest. A chart review of the standard office visit was reviewed and objective metabolic outcomes, such as weight, blood pressure (systolic and diastolic), lipids (total cholesterol and triglycerides), pulse, and glycohemoglobin were extracted and recorded. All measurements were evaluated pre-education and post-education. Demographic and clinical characteristics were obtained from all participants. Results: Thirty participants, consisting of patients with type 2 diabetes (n=15) and family members/friends (n=15), completed the study with pre-education and three month post-education results. Increases in diabetes knowledge, improvement in self-efficacy and increased family function were noted; however, there was no indication that a higher family function score would relate to a higher level of diabetes knowledge, a greater improvement of self-efficacy or improvement in metabolic outcomes. Although the test regarding self-efficacy (p=0.188) was not statistically significant p-value \u3e0.05, it was clinically significant as evidenced by the results of the metabolic testing. The family function score (p=0.016) and diabetes knowledge (p=0.035) were statistically significant p-value Conclusions: Results of the pilot study indicated positive changes in diabetes knowledge, self-efficacy and family function, as well as the majority of metabolic outcomes. Families with higher family functioning scores did not appear to have higher scores measuring diabetes knowledge or self-efficacy at the initiation of the study. Those families with higher family functioning scores showed no greater improvement in diabetes knowledge or self-efficacy scores than those families with lower family functioning scores at the conclusion of the study. This pilot study did not support inclusion of family in the educational process or disease management, but will support the use of a structured diabetes educational plan in the family practice setting to promote patient collaboration and outcomes. This study offers patients and their family members/friends education on maintenance and preventive measures, encouraging them to lead a healthy lifestyle, maintain their current health and prevent expensive complications, therefore reducing healthcare costs

THE BIG GARDEN PROJECT: Omaha Community Foundation

This executive summary of the final report documents the major findings of interviews and site visits conducted during the summer and fall of 2009 with representatives of BIG Garden and other community gardens in Omaha. The purpose of the study is to gather qualitative information for staff and sponsors on current gardening activities and other factors, relating to effective management and the implementation of best practices

Oxidative stress and antioxidant defense mechanisms linked to exercise during cardiopulmonary and metabolic disorders

Oxidative stress has been implicated in the pathophysiology of multiple human diseases, in addition to the aging process. Although various stimuli exist, acute exercise is known to induce a transient increase in reactive oxygen and nitrogen species (RONS), evident by several reports of increased oxidative damage following acute bouts of aerobic and anaerobic exercise. Although the results are somewhat mixed and appear disease dependent, individuals with chronic disease experience an exacerbation in oxidative stress following acute exercise when compared to healthy individuals. However, this increased oxidant stress may serve as a necessary “signal” for the upregulation in antioxidant defenses, thereby providing protection against subsequent exposure to prooxidant environments within susceptible individuals. Here we present studies related to both acute exercise-induced oxidative stress in those with disease, in addition to studies focused on adaptations resulting from increased RONS exposure associated with chronic exercise training in persons with disease

Structural changes of thermal sprayed graphene nano platelets film into amorphous carbon under sliding wear

© 2020 The Authors Graphene has become a promising candidate to protect surfaces against friction due to its strength and lubricating ability. In this study, graphene nano platelets (GNP) thin films have been deposited onto stainless steel substrates by axially injecting GNP suspension through high velocity oxy fuel thermal spray gun. The tribological performance of the films under dry sliding wear was investigated through unlubricated ball on disc sliding wear test against a sintered alumina counter body ball under 5 N load. The understanding of the behaviour of the GNPs under sliding wear will be useful for improving the performance of graphene-based coatings which are in demand for wear resistant applications. A film was deposited showing significant improvements in friction with coefficient of friction value reduced by 7 times compared to uncoated stainless steel, even for a discontinuous film. A morphological analysis shows sliding wear led to change in particle shape from angular flakes into randomly oriented circles. Interatomic bonding and structural analysis performed reveals oxidation defect formations during wear test. Structural degradation and oxidation of GNPs during the process led to formation of amorphous carbon from graphene. Amorphous carbon formation reduces the lubricating ability and strength of the film, leading to failure

Price Prediction in a Trading Agent Competition

The 2002 Trading Agent Competition (TAC) presented a challenging market game in the domain of travel shopping. One of the pivotal issues in this domain is uncertainty about hotel prices, which have a significant influence on the relative cost of alternative trip schedules. Thus, virtually all participants employ some method for predicting hotel prices. We survey approaches employed in the tournament, finding that agents apply an interesting diversity of techniques, taking into account differing sources of evidence bearing on prices. Based on data provided by entrants on their agents' actual predictions in the TAC-02 finals and semifinals, we analyze the relative efficacy of these approaches. The results show that taking into account game-specific information about flight prices is a major distinguishing factor. Machine learning methods effectively induce the relationship between flight and hotel prices from game data, and a purely analytical approach based on competitive equilibrium analysis achieves equal accuracy with no historical data. Employing a new measure of prediction quality, we relate absolute accuracy to bottom-line performance in the game

Where Does the Buck Stop? A Framework Analysis of Systematic Barriers and Supports to Effective Literacy Instructional Practices

Many claim that elementary school teachers fail to teach children to adequately read, but few ask teachers why this problem persists. This study illuminates the voices of the teachers as they shared their perceptions of which factors supported or hindered their best practices in literacy instruction. Forty-four elementary school teachers across the United States responded to an open-ended questionnaire detailing the people, structures, political, and fiscal supports and barriers to what they perceived as a comprehensive approach to literacy instruction. Using diagnostic and prognostic frames to structure teachers\u27 responses, findings from this study provide direct implications for administration at the school, district, and state levels as to where teachers perceive financial and personnel concentration should be to provide the best results in literacy instruction