Tribological behavior of composite-steel on rolling/sliding contacts for various loads

Composites have replaced metals in the bearing industry for the exclusive performances from its properties were it can accommodate resins, fabrics and additives. Roll-slip is common behaviors in application were non-conformal contact exhibits like bearings, rollers and cams. Two elements control the tribological behavior of the material which is the rolling and the sliding element. Composite-steel contacts were tested using a twin-disc setup with open tribo-system to study the influence of load on the frictional behavior of the polymer composites. The contacts were tested with four different loads under 20% slip ratio for a regular interval of time. The curves from the friction force with respect to different loads follows a tendency of linear increase in friction force were the rolling resistance is the dominating mechanism. For the given condition the macro level investigations shows the absence of transfer layer on the steel counterparts. The tendency of the friction curve and the micrograph explicitly deliberates the involvement of abrasion and adhesion in the harder polymer from metal counterpart. The temperature variable is isolated in case of the above research. The examination of the contact surface reveals the formation of craters on the junction of polymer and textile

Implications of uniformly distributed, empirically informed priors for phylogeographical model selection: A reply to Hickerson et al

Establishing that a set of population-splitting events occurred at the same time can be a potentially persuasive argument that a common process affected the populations. Oaks et al. (2013) assessed the ability of an approximate-Bayesian method (msBayes) to estimate such a pattern of simultaneous divergence across taxa, to which Hickerson et al. (2014) responded. Both papers agree the method is sensitive to prior assumptions and often erroneously supports shared divergences; the papers differ about the explanation and solution. Oaks et al. (2013) suggested the method's behavior is caused by the strong weight of uniform priors on divergence times leading to smaller marginal likelihoods of models with more divergence-time parameters (Hypothesis 1); they proposed alternative priors to avoid strongly weighted posteriors. Hickerson et al. (2014) suggested numerical approximation error causes msBayes analyses to be biased toward models of clustered divergences (Hypothesis 2); they proposed using narrow, empirical uniform priors. Here, we demonstrate that the approach of Hickerson et al. (2014) does not mitigate the method's tendency to erroneously support models of clustered divergences, and often excludes the true parameter values. Our results also show that the tendency of msBayes analyses to support models of shared divergences is primarily due to Hypothesis 1. This series of papers demonstrate that if our prior assumptions place too much weight in unlikely regions of parameter space such that the exact posterior supports the wrong model of evolutionary history, no amount of computation can rescue our inference. Fortunately, more flexible distributions that accommodate prior uncertainty about parameters without placing excessive weight in vast regions of parameter space with low likelihood increase the method's robustness and power to detect temporal variation in divergences.Comment: 24 pages, 4 figures, 1 table, 14 pages of supporting information with 10 supporting figure

How to Influence People

One of the most important skills that you need to develop for success in life is to influence people. By influencing people you help people to do better and encourage them to see things from a different view point

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कृपया पूरा लेखा पढ

Successful Career and its Attributes

Career planning should be done regularly so as to move forward in our jobs and careers and hence you should start as early as possible. It should be taken as an enjoyable activity which is liberating and fulfilling and it helps you to achieve your goals in your career. It should be taken as a rewarding and positive experience. Career planning should be done annually. Block all distractions and focus on your career and think what you really want to get out of your career and life. When career planning is done annually, you feel more secure in career choice and you will be prepared for any uncertainties that lie ahead in your jobs and career. Once it is done, take time off to review and reflect on the path; whether it was the correct decision. Also think of the things that you could have done differently. Your attitudes, likes, dislikes, needs and wants might have changed and hence move on with the new passion. Even after the review and self-assessment, if you find that you wish to continue with the same decision, and then your choice was correct. Sometime your hobbies could be made to transform into a career which will give you dedication and success. Keep a record of accomplishments in work so that a powerful resume is always ready in hand. Identify the transferable skills in you which would be valuable for many other jobs. Information about trends in career and job is also important and vital for long-term success. Once you gain knowledge about career trends, you can concentrate on developing a unique set of accomplishments, skills and education. Exploring new education and training opportunities also leads to power and success. We should never miss an opportunity to learn and grow more as a person and hence always find new training opportunities

Music Therapy Interventions for End-of-Life Care: An Integrative Literature Review

Music therapy plays an integral role in end-of-life care, positively impacting emotional, social, physical, cognitive and spiritual health. The purpose of this integrative review was to collect and compile studies (N= 55) between 2000 and 2016 on the topic of music therapy interventions in end-of-life care, in order to provide both music therapy students and therapists access to the most recent and commonly used music therapy interventions and goals. Results of the integrative literature review indicate that the most common intervention for all age groups in end-of-life care is songwriting and composition, with the most common therapeutic goal being emotional expression and catharsis. Details of music therapy interventions, goals and song details are written in tables for readers to refer to as a guide. Further research is needed with each specific age group and setting, in order to provide refined results beyond what is revealed through this review. Additionally, evaluating therapeutic outcomes of the interventions and goals obtained through this integrative review is another step that can be taken for future research

Alkali treatment and its effect on tribological properties of naturally woven coconut sheath polyester composite

In the recent years natural fibres have drawn great interest for its bio-degradability, low cost and its availability in nature. Among different types of natural fibres, naturally woven coconut sheath fibres are one of the recently explored alternatives for synthetic fibres. These fibres are generally treated with alkali for enhancing mechanical properties and reinforcing characteristics. Tribological applications like gears, cams, bearings, etc. can be benefited from such composites. In most cases chemical treatment are done favouring the structural properties however, their influence on tribological properties are rather not considered. In the current research, hybrid composites (polyester resin with naturally woven coconut sheath (N) and glass fibres (G)) were tested against hardened steel counterface in a pin on disc configuration. Tests were performed at 40 N normal force and 3.5 m/s sliding velocity. From the results all hybrid combinations except (NNN) shows degrading wear properties with the alkaline treatment. The friction properties are modified by having low friction coefficients for all combinations except NGN and GGG hybrids. From the observed SEM images the surface morphology of NNN hybrid significantly differs from the rest of the combinations in both treated and untreated specimens. The partial removal of individual phase (resin) prevails in untreated specimen for which the fibres are highly visible. However, such phenomenon is not dominant in the alkali treated material showing better reinforcing behaviour complimenting low friction properties. The alkali treated specimen has reduced fibre size comparing the untreated specimen which results in low wear resistance. Compromise between friction and wear properties between each other the untreated fibres are best suited for tribological applications. Furthermore, investigations on treatment process and other treatments might have some influence in tribological behaviour