163 research outputs found

    Megawatt solar power systems for lunar surface operations

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    The work presented here shows that a solar power system can provide power on the order of one megawatt to a lunar base with a fairly high specific power. The main drawback to using solar power is still the high mass, and therefore, cost of supplying energy storage through the solar night. The use of cryogenic reactant storage in a fuel cell system, however, greatly reduces the total system mass over conventional energy storage schemes

    Applying experimental micro-tool wear measurement techniques to industrial environments

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    Productivity in micro-milling is hindered by premature fracture of tools and difficulty predicting wear. This work builds upon previous investigations into tool wear mechanisms and coatings for micro-mills.The technology readiness level of this work exceeds previous studies by investigating the micro-mills for practical applications and comparing this data. 0.5 mm micro end mills are tested with different coatings on CuZn38, and wear curves produced both in the case of simple straight slot testing and milling of complex parts representing industrial applications. The results show that curves produced using straight slots can be used to predict the behaviour of tools used to machine industrial parts. Due to interrupted cutting, tools used in straight slot tests reach the end of steady state wear after approximately 12 s of cutting as compared with 170 s in continuous milling. Typical cutting forces seen for the tools are in the order of 2–4 N. Catastrophic failure is seen towards the end of tool life for a TiAlN tool with a cutting force of over 30 N seen. For the first time a comparison has been made between fundamental tool wear studies and tool wear observed when producing test pieces representative to micro-industrial parts. This presents a novel perspective on tool wear and facilitates the integrating of existing micro-milling research into industr

    Seventy-Five Years (1940-2015) of Lehigh University\u27s Chemistry Department

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    The 75-years 1940 to 2015 have been exciting ones for the Department of Chemistry; new buildings, new programs, energetic young faculty, enhanced research image, and a far broader coverage of Chemistry than our ancestors ever presumed. Five chairs guided the department through its first 75-years but it took 11 chairs (with two of them serving twice) to manage the second 75-years. As one of the Lehigh founding departments in 1865 our first 75-years have already been covered. The reader is directed to a history written by Robert D. Billinger, A History of the Department of Chemistry and Chemical Engineering of Lehigh University, Bethlehem, Pennsylvania (1866-1941) which is available in original in the Lehigh Archives and as an on-line document. This sesquicentennial volume is also available in hardcopy with original illustrations in the archives or on-line

    An analysis of the quality of experimental design and reliability of results in tribology research

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    In recent years several high profile projects have questioned the repeatability and validity of scientific research in the fields of psychology and medicine. In general, these studies have shown or estimated that less than 50% of published research findings are true or replicable even when no breaches of ethics are made. This high percentage stems from widespread poor study design; either through the use of underpowered studies or designs that allow the introduction of bias into the results. In this work, we have aimed to assess, for the first time, the prevalence of good study design in the field of tribology. A set of simple criteria for factors such as randomisation, blinding, use of control and repeated tests has been made. These criteria have been used in a mass review of the output of five highly regarded tribology journals for the year 2017. In total 379 papers were reviewed by 26 reviewers, 28% of the total output of the journals selected for 2017. Our results show that the prevalence of these simple aspects of study design is poor. Out of 290 experimental studies, 2.2% used any form of blinding, 3.2% used randomisation of either the tests or the test samples, while none randomised both. 30% repeated experiments 3 or more times and 86% of those who repeated tests used single batches of test materials. 4.4% completed statistical tests on their data. Due to the low prevalence of repeated tests and statistical analysis it is impossible to give a realistic indication of the percentage of the published works that are likely to be false positives, however these results compare poorly to other more well studied fields. Finally, recommendations for improved study design for researchers and group design for research group leaders are given

    How PETE comes to matter in the performance of social justice education

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    Background: For over four decades there have been calls for physical education (PE) and physical education teacher education (PETE) to address social inequality and foster social justice. Yet, as numerous studies demonstrate, attempts to educate for social justice in PETE are infrequent and rarely comprehensive. This raises the question why it appears to be possible in some situations but not others, and for some students and not others.    Purpose: The purpose of this paper is to examine the multiple socio-political networks or assemblages in which PETE is embedded and explore how these shape the possibilities for students to engage with the concept of social justice and sociocultural issues when learning to teach PE. Two research questions guided this study: How does an orientation for social justice education within education policy affect the standards for enacting PETE programs? How is social justice education encouraged within PETE programs? Methodology: Methodology: Drawing from a broader study of over 70 key personnel in more than 40 PETE programs, we examined how faculty in PETE understand their professional world, identify their subjective meanings of their experiences, and address sociocultural issues (SCI) and social justice education (SJE) within PETE. Data sources included an initial survey, a semi-structured interview, and program artifacts. We analyze the ways that SJE/SCI was represented in three national settings (England, the United States, and New Zealand) and identified common themes. Results:  Examination of each national setting reveals ways that SJE and SCI were enabled and constrained across the national, programmatic, and individual level in each of the countries. The coherence of explicit National policy and curricula, PETE program philosophies, and the presence of multiple individual interests in social justice served to reify a sociocultural agenda. Conversely possibilities were nullified by narrow or general National Standards, programs that failed to acknowledge sociocultural interests, and the absence of a critical mass of actors with a socio-critical orientation. These differences in assemblage culminated in variations in curriculum time that served to restrict or enable the breadth, frequency, and consistency of the messages surrounding SCI in PETE Conclusion: These findings highlight the importance of acknowledging socio-political networks where PETE operates. The agency of PETEs to enact pedagogies that foreground sociocultural interests is contingent on congruity of the networks. The authors caution that although the ‘perfect storm’ of conditions have a profound influence of the possibility of transformational learning of SCI in PETE, this arrangement is always temporary, fluid, and subject to changes in any of the three network levels. Additionally, the success of PETE in enabling graduating PE teachers to recognize the inequities that may be reinforced through the ‘hidden curriculum’ and to problematize the subject area is contingent on the expectations of the schools in which they teach.   

    Reclaiming the humanity in personality Disorder.

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    This paper provides a commentary upon the nursing care of individuals diagnosed with personality disorder and associated education courses. The discussion focuses upon recent policy trends in the UK as a point of departure. This policy discourse is critical of mainstream mental health services in previously operating to exclude such individuals. One of the consequences has been a recent growth in interest in relevant training courses, many of which devote significant attention to staff attitudes regarding this client group. Various previous researchers and commentators have remarked upon the implications for practice of a perceived negative attitude among care staff. We reflect upon our own anecdotal experience of developing and delivering new university-based courses for practitioners working in the field of personality disorder to offer a particular critique of the UK context, in which this policy, training, and practice is framed. Social constructionist theories are drawn on to offer insights into public and practitioner discourse and the possible effects on therapeutic relationships. The available discourse constructs individuals with a diagnosis of personality disorder as essentially different from other people. We argue that staff training and practice development initiatives are likely to be more successful if such discourse is challenged, and attempts are made in therapeutic encounters to recognize shared characteristics and positive attributes as much as perceived difference and negative attributes. We refer to this as a re-engagement with common humanity. Despite the singular national context, the discursive themes explored are not necessarily restricted to the UK

    Promiscuous Binding in a Selective Protein: The Bacterial Na+/H+ Antiporter

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    The ability to discriminate between highly similar substrates is one of the remarkable properties of enzymes. For example, transporters and channels that selectively distinguish between various solutes enable living organisms to maintain and control their internal environment in the face of a constantly changing surrounding. Herein, we examine in detail the selectivity properties of one of the most important salt transporters: the bacterial Na/H antiporter. Selectivity can be achieved at either the substrate binding step or in subsequent antiporting. Surprisingly, using both computational and experimental analyses synergistically, we show that binding per se is not a sufficient determinant of selectively. All alkali ions from Li to Cs were able to competitively bind the antiporter's binding site, whether the protein was capable of pumping them or not. Hence, we propose that NhaA's binding site is relatively promiscuous and that the selectivity is determined at a later stage of the transport cycle

    Age-dependent effects of protein restriction on dopamine release

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    FUNDING AND DISCLOSURE This work was supported by the Biotechnology and Biological Sciences Research Council [grant # BB/M007391/1 to J.E.M.], the European Commission [grant # GA 631404 to J.E.M.], The Leverhulme Trust [grant # RPG-2017-417 to J.E.M.] and the Tromsø Research Foundation [grant # 19-SG-JMcC to J. E. M.). The authors declare no conflict of interest. ACKNOWLEDGEMENTS The authors would like to acknowledge the help and support from the staff of the Division of Biomedical Services, Preclinical Research Facility, University of Leicester, for technical support and the care of experimental animals.Peer reviewedPublisher PD
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