Transient thermal analysis of a data centre cooling system under fault conditions

Data centres housing the IT infrastructure of large organisations constitute a considerable technical challenge to ensure 100% operational availability for mission critical IT systems. Specifying plant cooling systems to maintain suitable temperature levels and dissipate the heat generated can be carried out using industry standard design methods. However, accounting for perturbations in cooling due to failure of plant and restart of backup systems requires for faster thermal transients to be addressed than would normally be encountered in building system analysis. It is in this context that this paper describes the modelling and analysis of a 5 MW chilled water cooling system used for the cooling of a recently constructed UK data centre. The model has been developed using the TRNSYS software and includes a full model of the energy transfers for the data centre including chillers, hydraulic network, valve models and each of the 70 Room Air Conditioning Units. The coupling between the data centre air temperature levels and the cooler system has enabled a full assessment of the cooling system design in response to system perturbations. A number of scenarios are examined involving the failure of the chillers and how the inherent thermal inertia of the system plus additional inertia achieved through buffer vessels allowed a suitable design to be achieved. The detailed transient analysis model allowed the sizing of these vessels effectively and to gain a better understanding of the chilled water plant operation, both in normal conditions and in the case of failure

Understanding Organizational Creativity: Relationships among Cross-level Variables and Creativity in Research and Development Organizations

We examined the association of creativity with creative personality, domain expertise, non-controlling supervision, and organizational learning culture, as well as cross-level interactions in R&D organizations. Using HLM, domain expertise and non-controlling supervision were found to be positively associated with creativity. Practical implications and recommendations for further research are provide

Quality appraisal as a part of the systematic review: a review of current methods

Systematic reviews frequently underpin national and international practice guidelines. Different approaches to the systematic review process, in particular quality appraisal, have been advocated. This paper discusses these approaches and highlights possible limitations which might impact upon the validity of the conclusions drawn. Practical alternatives are offered upon which systematic reviews may be appraised and conducted

Recreation of the terminal events in physiological integrin activation.

Increased affinity of integrins for the extracellular matrix (activation) regulates cell adhesion and migration, extracellular matrix assembly, and mechanotransduction. Major uncertainties concern the sufficiency of talin for activation, whether conformational change without clustering leads to activation, and whether mechanical force is required for molecular extension. Here, we reconstructed physiological integrin activation in vitro and used cellular, biochemical, biophysical, and ultrastructural analyses to show that talin binding is sufficient to activate integrin alphaIIbbeta3. Furthermore, we synthesized nanodiscs, each bearing a single lipid-embedded integrin, and used them to show that talin activates unclustered integrins leading to molecular extension in the absence of force or other membrane proteins. Thus, we provide the first proof that talin binding is sufficient to activate and extend membrane-embedded integrin alphaIIbbeta3, thereby resolving numerous controversies and enabling molecular analysis of reconstructed integrin signaling

The Clergy in English-Canadian Fiction

The stress in the study of the clergy in Canadian fiction is on the clergyman's position in both the Church and society. The early novels, those written before 1920, are divided into two categories according to their common traits. The novels in the first category, the "evangelical romance," which is discussed in the first chapter, are found to have a surprisingly large number of common traits. Of these evangelical romances those of Ralph Connor were immensely popular when they were first written and until well on into the 1930's. Various factors in the novels account for the popularity. Although many of these features are no longer popular, Connor's novels ae still valuable for what they reveal of life in the early Canadian West and especially of the importance and nature of its religious life and its clergyman. Of the seven evangelical romances studies, Ernest Seton's The Preacher of Cedar Mountain is judged to be the best by modern standards. In the second chapter, seven "ecclesiastical" novels ae discussed. These novels have a number of features which clearly distinguish them from the evangelical romances. The seven are subdivided into two major groups. The first four novels discussed, The Lone Furrow, Committed to His Charge, Sunshine Sketches, and Arcadian Adventure's are all fairly objective in point of view and critical of laity and clergy. The miniters in the remaining three ecclesiastical novels are more like those in the evangelical novels, as are the laymen. The majority of clergymen and laymen in modern Canadian fection, which is discussed is chapter three, follow in the tradition of the first four ecclesiastical novels. The clergymen are discussed in two groups: six "prêtres manqué's" and three successful hypocrites. Ministers like those in the evangelical romances seem to have vanished from Canadian fiction, as do the devout churchmen of the second group of ecclesiastical novels. The peculiar nature of most of the clergymen in modern Canadian fiction reflects a decline in the importance of the church in society in general.Master of Arts (MA

Application of Dynamic System Identification to Timber Beams - part I

In this first part of a two-part paper, development of a method of dynamic system identification for timber beams is presented with an analytical verification of the method using a finite-element model. A method of global nondestructive evaluation for identifying local damage and decay in timber beams is investigated in this paper. Experimental modal analysis is used in conjunction with a previously developed damage localization algorithm. The damage localization algorithm utilizes changes in modal strain energy between the mode shapes of a calibrated model, representing the undamaged state of the beam of interest, and the experimentally obtained mode shapes for a timber beam. Analytical evaluations were performed to demonstrate and verify the use of this method of global nondestructive evaluation for the localization of damage or decay in timber beams. In a companion paper, experimental laboratory tests are presented that verify the use of dynamic system identification to locate damage within timber beams

A T8.5 Brown Dwarf Member of the Xi Ursae Majoris System

The Wide-field Infrared Survey Explorer has revealed a T8.5 brown dwarf (WISE J111838.70+312537.9) that exhibits common proper motion with a solar-neighborhood (8 pc) quadruple star system - Xi Ursae Majoris. The angular separation is 8.5 arc-min, and the projected physical separation is about 4000 AU. The sub-solar metallicity and low chromospheric activity of Xi UMa A argue that the system has an age of at least 2 Gyr. The infrared luminosity and color of the brown dwarf suggests the mass of this companion ranges between 14 and 38 Jupiter masses for system ages of 2 and 8 Gyr respectively.Comment: AJ in press, 12 pages LaTeX with 6 figures. More astrometric data and a laser guide star adaptive optics image adde

A Study of the Diverse T Dwarf Population Revealed by WISE

We report the discovery of 87 new T dwarfs uncovered with the Wide-field Infrared Survey Explorer (WISE) and three brown dwarfs with extremely red near-infrared colors that exhibit characteristics of both L and T dwarfs. Two of the new T dwarfs are likely binaries with L7+/-1 primaries and mid-type T secondaries. In addition, our follow-up program has confirmed 10 previously identified T dwarfs and four photometrically-selected L and T dwarf candidates in the literature. This sample, along with the previous WISE discoveries, triples the number of known brown dwarfs with spectral types later than T5. Using the WISE All-Sky Source Catalog we present updated color-color and color-type diagrams for all the WISE-discovered T and Y dwarfs. Near-infrared spectra of the new discoveries are presented, along with spectral classifications. To accommodate later T dwarfs we have modified the integrated flux method of determining spectral indices to instead use the median flux. Furthermore, a newly defined J-narrow index differentiates the early-type Y dwarfs from late-type T dwarfs based on the J-band continuum slope. The K/J indices for this expanded sample show that 32% of late-type T dwarfs have suppressed K-band flux and are blue relative to the spectral standards, while only 11% are redder than the standards. Comparison of the Y/J and K/J index to models suggests diverse atmospheric conditions and supports the possible re-emergence of clouds after the L/T transition. We also discuss peculiar brown dwarfs and candidates that were found not to be substellar, including two Young Stellar Objects and two Active Galactic Nuclei. The coolest WISE-discovered brown dwarfs are the closest of their type and will remain the only sample of their kind for many years to come.Comment: Accepted to ApJS on 15 January 2013; 99 pages in preprint format, 30 figures, 12 table

Traditional healers, faith healers and medical practitioners: the contribution of medical pluralism to bottlenecks along the cascade of care for HIV/AIDS in Eastern and Southern Africa.

OBJECTIVES: There are concerns that medical pluralism may delay patients' progression through the HIV cascade-of-care. However, the pathways of impact through which medical pluralism influence the care of people living with HIV (PLHIV) in African settings remain unclear. We sought to establish the manifestation of medical pluralism among PLHIV, and explore mechanisms through which medical pluralism contributes bottlenecks along the HIV care cascade. METHODS: We conducted a multicountry exploratory qualitative study in seven health and demographic surveillance sites in six eastern and southern African countries: Uganda, Kenya, Tanzania, Malawi, Zimbabwe and South Africa. We interviewed 258 PLHIV at different stages of the HIV cascade-of-care, 48 family members of deceased PLHIV and 53 HIV healthcare workers. Interviews were conducted using shared standardised topic guides, and data managed through NVIVO 8/10/11. We conducted a thematic analysis of healthcare pathways and bottlenecks related to medical pluralism. RESULTS: Medical pluralism, manifesting across traditional, faith-based and biomedical health-worlds, contributed to the care cascade bottlenecks for PLHIV through three pathways of impact. First, access to HIV treatment was delayed through the nature of health-related beliefs, knowledge and patient journeys. Second, HIV treatment was interrupted by availability of alternative options, perceived failed treatment and exploitation of PLHIV by opportunistic traders and healers. Lastly, the mixing of biomedical healthcare providers and treatment with traditional and faith-based options fuelled tensions driven by fear of drug-to-drug interactions and mistrust between providers operating in different health-worlds. CONCLUSION: Medical pluralism contributes to delays and interruptions of care along the HIV cascade, and mistrust between health providers. Region-wide interventions and policies are urgently needed in sub-Saharan Africa to minimise potential harm and consequences of medical pluralism for PLHIV. The role of sociocultural beliefs in mediating bottlenecks necessitate adoption of culture-sensitive approaches intervention designs and policy reforms appropriate to the context of sub-Saharan Africa