Roughness effects in turbulent forced convection

We conducted direct numerical simulations (DNSs) of turbulent flow over three-dimensional sinusoidal roughness in a channel. A passive scalar is present in the flow with Prandtl number $Pr=0.7$, to study heat transfer by forced convection over this rough surface. The minimal channel is used to circumvent the high cost of simulating high Reynolds number flows, which enables a range of rough surfaces to be efficiently simulated. The near-wall temperature profile in the minimal channel agrees well with that of the conventional full-span channel, indicating it can be readily used for heat-transfer studies at a much reduced cost compared to conventional DNS. As the roughness Reynolds number, $k^+$, is increased, the Hama roughness function, $\Delta U^+$, increases in the transitionally rough regime before tending towards the fully rough asymptote of $\kappa_m^{-1}\log(k^+)+C$, where $C$ is a constant that depends on the particular roughness geometry and $\kappa_m\approx0.4$ is the von K\'arm\'an constant. In this fully rough regime, the skin-friction coefficient is constant with bulk Reynolds number, $Re_b$. Meanwhile, the temperature difference between smooth- and rough-wall flows, $\Delta\Theta^+$, appears to tend towards a constant value, $\Delta\Theta^+_{FR}$. This corresponds to the Stanton number (the temperature analogue of the skin-friction coefficient) monotonically decreasing with $Re_b$ in the fully rough regime. Using shifted logarithmic velocity and temperature profiles, the heat transfer law as described by the Stanton number in the fully rough regime can be derived once both the equivalent sand-grain roughness $k_s/k$ and the temperature difference $\Delta \Theta^+_{FR}$ are known. In meteorology, this corresponds to the ratio of momentum and heat transfer roughness lengths, $z_{0m}/z_{0h}$, being linearly proportional to $z_{0m}^+$, the momentum roughness length [continued]...Comment: Accepted (In press) in the Journal of Fluid Mechanic

Fish culture in British East Africa

Volume: I

Theoretical analysis of the philosophy and practice of disciplined inquiry

2015 Spring.Includes bibliographical references.This dissertation theoretically examined the process of disciplined inquiry in the social sciences from its philosophical foundations to its extensions into practice. Key to conceptualization of disciplined inquiry were two regulative ideals: the commitment to the concepts that define the possibility of experience and the commitment to processes for combining the concepts of experience. The paradigm theory of Lincoln, Lynham, and Guba (e.g., Lincoln & Lynham, 2011; Lincoln, Lynham, & Guba, 2011) provided a sophisticated explanation of the possibility of experience that inquirers can commit to when engaging in disciplined inquires. Review of literature revealed an inadequacy in the state of theoretical understanding of processes for combining the concepts of experience. To develop a theoretical agenda of research for disciplined inquiry, the literature on paradigm theory and theory building was analyzed. A historical analysis of paradigm theory revealed milestones in more than 40 years of inquiry focused on conceptualization of the theory. A reverse engineering analysis theoretically examined paradigm theory and its milestones identified from the historical analysis for key features of the theoretical process. A revised conceptualization of disciplined inquiry was presented and a theoretical agenda for developing the underlying theoretical framework for the processes of combining the concepts of experience was outlined

Return to the Conservative View of Security Agreements in Commercial Transactions

The purpose of this comment is to explore judicial interpretation of what constitutes a security agreement, to delineate the arguments available to an attorney confronted with a deficient security agreement and to advocate a return to the conservative single document approach. Attorneys should also recognize that continued reliance on formal security agreements is advisable

A New Approach To Teaching Business Writing: Writing Across The Core -A Document Based Curriculum

This paper describes the transition that the Anisfield School of Business of Ramapo College of New Jersey made from a conventional Writing Across the Curriculum approach to a Writing Across the Business Core approach. The impetus for the change is explained as well as the creation and design of the program. The document driven program is analyzed, with special emphasis on faculty buy in. The rationale for the documents chosen is provided as is the logic behind the course sequence. The paper concludes with the results of the first assessment of the program

Risk Sharing, Crew Quality, Labor Shares and Wages in the Nineteenth Century American Whaling Industry

This paper examines 36.640 labor contracts signed between whalemen and the agents who organized 1,258 whaling voyages that departed from New Bedford, Massachusetts between January I. 1840 and December 31, 1858 and between January I and December 31, 1866. The contracts contain information on the whaleman's station (occupation) and on his lay (the fraction of output of the voyage that he was entitled to receive upon completion). The paper investigates the benefits associated with this unique contract. examines the occupational and spatial distribution of lays. and compares wages in whaling with those available in the merchant marine and those earned in shore based pursuits. It also attempts to assess the efficiency of this early labor market and to explore the relationship between the labor contract, crew quality. technical change. and productivity.

Design of a Multi-Color Plenoptic Camera for Snapshot Hyperspectral Imaging

The design of a custom camera lens including: a two-lens optical system, filter array, and iris has been developed enabling a greyscale plenoptic camera to acquire full field-of-view, 2D, instantaneous hyperspectral measurements. This work focuses on the use of 7 discrete color filters and their effect on the image quality. It was determined that the placement of the filters inside the aperture plane of the camera was paramount to mitigating image artifacts. In addition, design rules were developed such that the optimal optical parameters (image distance, working distance, and focal length) can be easily determined from a few charts

The impacts of urbanisation and climate change on urban flooding and urban water quality: a review of the evidence concerning the United Kingdom

Study region: United Kingdom (UK). Study focus: Climate change and urbanization pose significant threats for flooding and water quality in urban areas. This paper reviews the evidence concerning the combined impacts of urbanisation and climate on the urban water environment of inland catchments of the United Kingdom and assesses the degree of confidence in reported directions of change and response. It also assesses the utility of the evidence for setting environmental legislation and managing the urban water environment in the future and identifies knowledge gaps that limit effective and management interventions. New hydrological insights: There is a lack of nationally research focused on the dual impacts of climate change and urbanisation on flooding and water quality in UK urban areas. This is despite there being a clear acceptance that flood risk is increasing, water quality is generally not meeting desirable levels, and that combined population and climate change projections pose a pressing challenge. The available evidence has been found to be of medium-high confidence that both pressures will result in (i) an increase in pluvial and fluvial flood risk, and (ii) further reduction in water quality caused by point source pollution and altered flow regimes. Evidence concerning urban groundwater flooding, diffuse pollution and water temperature was found to be more sparse and was ascribed a low-medium confidence that both pressures will further exacerbate existing issues. The confidence ascribed to evidence was also found to reflect the utility of current science for setting policy and urban planning. Recurring factors that limit the utility of evidence for managing the urban environment includes: (i) climate change projection uncertainty and suitability, (ii) lack of sub-daily projections for storm rainfall, (iii) the complexity of managing and modelling the urban environment, and (iv) lack of probable national-scale future urban landuse projections. Suitable climate products are increasingly being developed and their application in applied urban research is critical in the wake of a series of extreme flooding events across the UK and timely for providing state-of-the-art evidence on which to base possible future water quality legislation in a post Brexit-WFD era

Turbulent flow over a long flat plate with uniform roughness

For turbulent boundary-layer flow under a uniform freestream speed U∞ over a plate of length L, covered with uniform roughness of nominal sand-grain scale k_s, the physical behaviors underlying two distinguished limits at large Re_L≡U∞L/ν are explored: the fully rough wall flow where k_s/L is fixed and the long-plate limit where Re_k≡U∞k_s/ν is fixed. For the fully rough limit it is shown that not only is the drag coefficient C_D independent of Re_L but that a universal skin-friction coefficient C_f and normalized boundary-layer thickness δ/k_s can be found that depends only on ks_/x, where x is the downstream distance. In the long-plate limit, it is shown that the flow becomes asymptotically smooth at huge Re_L at a rate that depends on Re_k. Comparisons with wind-tunnel and field data are made

Indiana Consortium for Innovation in Biomedical Imaging

poster abstractThe Indiana Consortium for Innovation in Biomedical Imaging (Indiana-CIBI) has been established to leverage the biomedical imaging strengths of several major academic institutions throughout Indiana. This initiative provides the environment, infrastructure, and resources necessary for establishing one of the premier translational, research and educational imaging networks in the United States. The Indiana-CIBI will facilitate the identification of crucial clinical problems and unmet research needs; stimulate the development of innovative solutions; and help translate optimized patient care services into practice at partner health-care delivery facilities. The objectives of the Indiana-CIBI include: Providing national leadership in translation from concept to practice. Encouraging targeted problem-driven technology development. Nurturing innovation and progress through facile access to advanced resources. Focusing Indiana state-wide interdisciplinary partnerships in the development of new, innovative imaging technologies and the utilization of imaging resources. Cultivating investigator engagement and channeling intrinsic motivation. The stated objectives of the Indiana-CIBI define the operational model for the consortium. Key steps in the innovation-focused process include: 1) Identification of critical clinical or biomedical research needs by physician or biomedical investigator(s); 2) Creation of innovative solutions through innovation incubator teams, imaging innovation marathons, and crowdsourcing solicitations; 3) Translation to practice through a large medical physics/radiology network; and 4) Translation to advanced core services through the Indiana-CTSI core resource network. Critical success factors for the Indiana-CIBI include tight integration within academic health care facilities, consolidation of fragmented resources, and expansion of critical support resources, eliminating the need to duplicate some types of services across multiple sites in Indiana. For further information regarding the Indiana Consortium for Innovation in Biomedical Imaging and its programs please contact Mark Holland or Gary Hutchins at [email protected]. The Indiana-CIBI is supported, in part, by contributions from the IUPUI Office of the Vice Chancellor for Research