Gliding swifts attain laminar flow over rough wings.

Directory of Open Access Journals (Sweden)

David Lentink

Full Text Available Swifts are among the most aerodynamically refined gliding birds. However, the overlapping vanes and protruding shafts of their primary feathers make swift wings remarkably rough for their size. Wing roughness height is 1-2% of chord length on the upper surface--10,000 times rougher than sailplane wings. Sailplanes depend on extreme wing smoothness to increase the area of laminar flow on the wing surface and minimize drag for extended glides. To understand why the swift does not rely on smooth wings, we used a stethoscope to map laminar flow over preserved wings in a low-turbulence wind tunnel. By combining laminar area, lift, and drag measurements, we show that average area of laminar flow on swift wings is 69% (n = 3; std 13% of their total area during glides that maximize flight distance and duration--similar to high-performance sailplanes. Our aerodynamic analysis indicates that swifts attain laminar flow over their rough wings because their wing size is comparable to the distance the air travels (after a roughness-induced perturbation before it transitions from laminar to turbulent. To interpret the function of swift wing roughness, we simulated its effect on smooth model wings using physical models. This manipulation shows that laminar flow is reduced and drag increased at high speeds. At the speeds at which swifts cruise, however, swift-like roughness prolongs laminar flow and reduces drag. This feature gives small birds with rudimentary wings an edge during the evolution of glide performance.

Bone augmentation of the osteo-odonto alveolar lamina in MOOKP--will it delay laminar resorption?

Science.gov (United States)

Iyer, Geetha; Srinivasan, Bhaskar; Agarwal, Shweta; Rishi, Ekta; Rishi, Pukhraj; Rajan, Gunaseelan; Shanmugasundaram, Shanmugasundaram

2015-07-01

We aimed to describe a new technique and analyse the early outcomes of augmenting the canine tooth using a mandibular bone graft in an attempt to delay or retard the process of laminar resorption following the modified osteo odonto keratoprosthesis (MOOKP) procedure. This was a retrospective case series. Eyes that underwent the bone augmentation procedure between December 2012 and February 2014 were retrospectively analysed. The procedure, performed by the oromaxillofacial surgeon, involved securing a mandibular bone graft beneath the periosteum on the labial aspect of the canine tooth chosen to be harvested for the MOOKP procedure. This procedure was performed simultaneously with the Stage 1 A of the MOOKP. Three months later, the tooth was harvested and fashioned into the osteo-odonto alveolar lamina similar to the method described in the Rome-Vienna Protocol. The bone augmentation procedure was performed in 11 eyes (five SJS/ six chemical injuries). The mean follow-up after Stage 2 of MOOKP procedure in these eyes was 7.45 months (2 to 20 months). Complications noted were peripheral laminar exposure (three eyes-SJS) and bone graft exposure and necrosis in the mouth (nine-SJS). No evidence of clinical laminar resorption was noted in any of the eyes. Laminar resorption in MOOKP can lead to vision and globe threatening complications due to the consequent cylinder instability and chances of extrusion. Augmenting the bone on the labial aspect of the canine tooth might have a role to play in delaying or preventing laminar resorption.

Long-term pavement performance ancillary information management system (AIMS) reference guide.

Science.gov (United States)

2012-11-01

This document provides information on the Long-Term Pavement Performance (LTPP) program ancillary information. : Ancillary information includes data, images, reference materials, resource documents, and other information that : support and extend the...

New developments in segment ancillary logic for FASTBUS

International Nuclear Information System (INIS)

Walz, H.V.; Bertolucci, B.

1983-01-01

Segment Ancillary Logic hardware for FASTBUS systems provides logical functions required in common by all devices attached to a segment. It controls the execution of arbitration cycles, and geographical address cycles, and generates the system handshake responses for broadcast operations. The mandatory requirements for Segment Ancillary Logic in the FASTBUS specifications are reviewed. A detailed implementation based on ECL logic is described, and the hardware to be used on an ECL cable segment for an experimental FASTBUS system at SLAC is shown

Review of Standby and Ancillary Services in the Context of Behind-the-Meter Photovoltaics

Energy Technology Data Exchange (ETDEWEB)

Gagnon, Pieter J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Holm, Alison [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-04-25

The New Mexico Public Regulatory Commission (NMPRC) requested information on the following topics: Overview of ancillary and standby services. Examples of how ancillary and standby services are defined, used, and analyzed in other jurisdictions. Considerations regarding how ancillary and standby services may be economically valued. Background information on how ancillary and standby services differ from fixed costs to serve owners of behind-the-meter solar photovoltaic (BTM PV) systems.

Evaluation of Contribution for Voltage Control Ancillary Services Based on Social Surplus

Science.gov (United States)

Ueki, Yuji; Hara, Ryoichi; Kita, Hiroyuki; Hasegawa, Jun

Reactive power supply plays an important role in active power supply with adequate system voltages. Various pricing mechanism for reactive power supply have been developed and some of them are adopted in some power systems, however they are in a trial stage. The authors also focus on development of a pricing method for reactive power ancillary services. This problem involves two technical issues: rational estimation of the cost associated with reactive power supply and fair and transparent allocation of the estimated cost among the market participants. This paper proposes methods for evaluating the contribution of generators and demands.

Creating competitive markets for ancillary services

Energy Technology Data Exchange (ETDEWEB)

Hirst, E.; Kirby, B.

1997-10-01

This report describes the structure of, and results from, a spreadsheet model. The model simulates markets for seven services: losses, regulation, spinning reserve, supplemental reserve,load following, energy imbalance, and voltage support. For completeness, the model also calculates costs for system control, although this service will continue to be provided solely the the system operator under cost-based prices. This computer model demonstrated the likely complexity of markets for energy and ancillary services. This complexity arises because these markets are highly interdependent. Because these markets are interactive, the costs and therefore the prices of these services will vary considerably as functions of system load and the current spot price of energy. The price of ancillary services in aggregate is highly correlated with the price of energy. A base-case utility was developed for use with the model and included in the report.

Fully developed laminar flow of non-Newtonian liquids through annuli: comparison of numerical calculations with experiments

Energy Technology Data Exchange (ETDEWEB)

Escudier, M.P.; Smith, S. [Department of Engineering, Mechanical Engineering, University of Liverpool, Brownlow Hill, Liverpool L69 3GH (United Kingdom); Oliveira, P.J. [Departamento de Engenharia Electromecanica, Universidade da Beira Interior, Rua Marques D' Avila e Boloma, 6200 Covilha (Portugal); Pinho, F.T. [Centro de Estudos de Fenomenos de Transporte, DEMEGI, Faculdade de Engenharia, Universidade do Porto, Rua Roberto Frias, 4200-465 Porto (Portugal)

2002-07-01

Experimental data are reported for fully developed laminar flow of a shear-thinning liquid through both a concentric and an 80% eccentric annulus with and without centrebody rotation. The working fluid was an aqueous solution of 0.1% xanthan gum and 0.1% carboxymethylcellulose for which the flow curve is well represented by the Cross model. Comparisons are reported between numerical calculations and the flow data, as well as with other laminar annular-flow data for a variety of shear-thinning liquids previously reported in the literature. In general, the calculations are in good quantitative agreement with the experimental data, even in situations where viscoelastic effects, neglected in the calculations, would be expected to play a role. (orig.)

An analysis of ongoing trends in airline ancillary revenues

OpenAIRE

Warnock-Smith, David; O'Connell, John F.; Maleki, Mahnaz

2017-01-01

This paper examines the performance of the two core classifications of airline ancillary revenues, which are unbundled products and commission based income. It also investigates the willingness of passengers to pay (WTP) for these services together with what type of ancillary items are acceptable at a particular price point. The study found that passengers value a narrow range of perceived ‘necessity’ products and services such as food and drink, checked baggage and seat assignment as opposed...

Ancillary Services Provided from DER

Energy Technology Data Exchange (ETDEWEB)

Campbell, J.B.

2005-12-21

Distributed energy resources (DER) are quickly making their way to industry primarily as backup generation. They are effective at starting and then producing full-load power within a few seconds. The distribution system is aging and transmission system development has not kept up with the growth in load and generation. The nation's transmission system is stressed with heavy power flows over long distances, and many areas are experiencing problems in providing the power quality needed to satisfy customers. Thus, a new market for DER is beginning to emerge. DER can alleviate the burden on the distribution system by providing ancillary services while providing a cost adjustment for the DER owner. This report describes 10 types of ancillary services that distributed generation (DG) can provide to the distribution system. Of these 10 services the feasibility, control strategy, effectiveness, and cost benefits are all analyzed as in the context of a future utility-power market. In this market, services will be provided at a local level that will benefit the customer, the distribution utility, and the transmission company.

Aerodynamics and Percolation: Unfolding Laminar Separation Bubble on Airfoils

Science.gov (United States)

Traphan, Dominik; Wester, Tom T. B.; Gülker, Gerd; Peinke, Joachim; Lind, Pedro G.

2018-04-01

As a fundamental phenomenon of fluid mechanics, recent studies suggested laminar-turbulent transition belonging to the universality class of directed percolation. Here, the onset of a laminar separation bubble on an airfoil is analyzed in terms of the directed percolation model using particle image velocimetry data. Our findings indicate a clear significance of percolation models in a general flow situation beyond fundamental ones. We show that our results are robust against fluctuations of the parameter, namely, the threshold of turbulence intensity, that maps velocimetry data into binary cells (turbulent or laminar). In particular, this percolation approach enables the precise determination of the transition point of the laminar separation bubble, an important problem in aerodynamics.

Optimization of recirculating laminar air flow in operating room air conditioning systems

Directory of Open Access Journals (Sweden)

Enver Yalcin

2016-04-01

Full Text Available The laminar flow air-conditioning system with 100% fresh air is used in almost all operating rooms without discrimination in Turkey. The laminar flow device which is working with 100% fresh air should be absolutely used in Type 1A operating rooms. However, there is not mandatory to use of 100% fresh air for Type 1B defined as places performed simpler operation. Compared with recirculating laminar flow, energy needs of the laminar flow with 100 % fresh air has been emerged about 40% more than re-circulated air flow. Therefore, when a recirculating laminar flow device is operated instead of laminar flow system with 100% fresh air in the Type 1B operating room, annual energy consumption will be reduced. In this study, in an operating room with recirculating laminar flow, optimal conditions have been investigated in order to obtain laminar flow form by analyzing velocity distributions at various supply velocities by using computational fluid dynamics method (CFD.

Colombian ancillary services and international connections: Current weaknesses and policy challenges

International Nuclear Information System (INIS)

Carvajal, S.X.; Serrano, J.; Arango, S.

2013-01-01

Ancillary services are required to maintain the unity, stability, and quality of power systems. In Colombia these services are required to operate the national power system and the international connections with the neighboring countries. The system is influenced by factors ranging from system's topology to social and political aspects, such as the large number of terrorist attacks. In light of these particularities, we consider Colombia as a learning lab for ancillary services in the region. Colombia's power system relies on three ancillary services for its operation, namely frequency regulation, voltage control, and blackstart service. From 2010 Special Protection Systems were also added. In this paper we first analyze the technical aspects, operational restrictions, financial management, and the most relevant regulatory conditions of these ancillary services of the SIN. We also take into consideration the main regulatory characteristics and statistical data related to energy exchanges that have taken place between Colombia and Venezuela and Ecuador. Thereafter, we depict the main weaknesses and policy challenges that Colombia must address in order to increase the effectiveness and coverage of ancillary services in both the SIN and in the international interconnections. Finally, we propose new market oriented regulations to encourage investments and new tools for international connections. - Highlights: ► Blackout of 2007 forces Colombian regulator to improve security of power system. ► Four ancillary services are currently used for secure operation of Colombian system. ► Special Protection Systems service added in 2010. ► Frequency control is the only remunerated service in Colombia. ► Legislation should exist for remuneration of voltage control and black start services.

Exploiting ancillary services from distributed generation - perspectives for the Danish power system

DEFF Research Database (Denmark)

Nyeng, Preben; Pedersen, Knud Ole Helgesen; Østergaard, Jacob

2007-01-01

The share of the electric power production originating from distributed energy resources has rapidly increased during the recent past. However when it comes to ancillary services necessary to ensure the stability and appropriate operation of the power system, the distributed energy resources take...... a very passive role. This paper outlines suggestions on how to activate the potential of ancillary services from distributed energy resources, thereby exploiting their ability to contribute to power system operation. Furthermore, methods for integrating the ancillary service delivery into a deregulated...

Heat transfer of laminar mixed convection of liquid

CERN Document Server

Shang, De-Yi

2016-01-01

This book presents a new algorithm to calculate fluid flow and heat transfer of laminar mixed convection. It provides step-by-step tutorial help to learn quickly how to set up the theoretical and numerical models of laminar mixed convection, to consider the variable physical properties of fluids, to obtain the system of numerical solutions, to create a series of formalization equations for the convection heat transfer by using a curve-fitting approach combined with theoretical analysis and derivation. It presents the governing ordinary differential equations of laminar mixed convection, equivalently transformed by an innovative similarity transformation with the description of the related transformation process. A system of numerical calculations of the governing ordinary differential equations is presented for the water laminar mixed convection. A polynomial model is induced for convenient and reliable treatment of variable physical properties of liquids. The developed formalization equations of mixed convec...

Chemical kinetic model uncertainty minimization through laminar flame speed measurements

Science.gov (United States)

Park, Okjoo; Veloo, Peter S.; Sheen, David A.; Tao, Yujie; Egolfopoulos, Fokion N.; Wang, Hai

2016-01-01

Laminar flame speed measurements were carried for mixture of air with eight C3-4 hydrocarbons (propene, propane, 1,3-butadiene, 1-butene, 2-butene, iso-butene, n-butane, and iso-butane) at the room temperature and ambient pressure. Along with C1-2 hydrocarbon data reported in a recent study, the entire dataset was used to demonstrate how laminar flame speed data can be utilized to explore and minimize the uncertainties in a reaction model for foundation fuels. The USC Mech II kinetic model was chosen as a case study. The method of uncertainty minimization using polynomial chaos expansions (MUM-PCE) (D.A. Sheen and H. Wang, Combust. Flame 2011, 158, 2358–2374) was employed to constrain the model uncertainty for laminar flame speed predictions. Results demonstrate that a reaction model constrained only by the laminar flame speed values of methane/air flames notably reduces the uncertainty in the predictions of the laminar flame speeds of C3 and C4 alkanes, because the key chemical pathways of all of these flames are similar to each other. The uncertainty in model predictions for flames of unsaturated C3-4 hydrocarbons remain significant without considering fuel specific laminar flames speeds in the constraining target data set, because the secondary rate controlling reaction steps are different from those in the saturated alkanes. It is shown that the constraints provided by the laminar flame speeds of the foundation fuels could reduce notably the uncertainties in the predictions of laminar flame speeds of C4 alcohol/air mixtures. Furthermore, it is demonstrated that an accurate prediction of the laminar flame speed of a particular C4 alcohol/air mixture is better achieved through measurements for key molecular intermediates formed during the pyrolysis and oxidation of the parent fuel. PMID:27890938

Computational Analysis of the G-III Laminar Flow Glove

Science.gov (United States)

Malik, Mujeeb R.; Liao, Wei; Lee-Rausch, Elizabeth M.; Li, Fei; Choudhari, Meelan M.; Chang, Chau-Lyan

2011-01-01

Under NASA's Environmentally Responsible Aviation Project, flight experiments are planned with the primary objective of demonstrating the Discrete Roughness Elements (DRE) technology for passive laminar flow control at chord Reynolds numbers relevant to transport aircraft. In this paper, we present a preliminary computational assessment of the Gulfstream-III (G-III) aircraft wing-glove designed to attain natural laminar flow for the leading-edge sweep angle of 34.6deg. Analysis for a flight Mach number of 0.75 shows that it should be possible to achieve natural laminar flow for twice the transition Reynolds number ever achieved at this sweep angle. However, the wing-glove needs to be redesigned to effectively demonstrate passive laminar flow control using DREs. As a by-product of the computational assessment, effect of surface curvature on stationary crossflow disturbances is found to be strongly stabilizing for the current design, and it is suggested that convex surface curvature could be used as a control parameter for natural laminar flow design, provided transition occurs via stationary crossflow disturbances.

Loads Providing Ancillary Services: Review of International Experience

Energy Technology Data Exchange (ETDEWEB)

Heffner, Grayson; Goldman, Charles; Kintner-Meyer, Michael

2007-05-01

In this study, we examine the arrangements for and experiences of end-use loads providing ancillary services (AS) in five electricity markets: Australia, the United Kingdom (UK), the Nordic market, and the ERCOT and PJM markets in the United States. Our objective in undertaking this review of international experience was to identify specific approaches or market designs that have enabled customer loads to effectively deliver various ancillary services (AS) products. We hope that this report will contribute to the ongoing discussion in the U.S. and elsewhere regarding what institutional and technical developments are needed to ensure that customer loads can meaningfully participate in all wholesale electricity markets.

The Nordic approach to market-based provision of ancillary services

International Nuclear Information System (INIS)

Kristiansen, Tarjei

2007-01-01

This paper presents an overview of the markets for ancillary services, which are regulated and traded differently within and across borders in the Nordic countries. We describe the services provided and their characteristics in terms of definition, participation, contracting approach and duration, selection of offers, and dispatch criteria. Further, we assess the costs, specify the payments, and discuss cost allocation, and we conclude with a policy discussion of ancillary services in the Nordic countries. (author)

Applications of Laminar Weak-Link Mechanisms for Ultraprecision Synchrotron Radiation Instruments

International Nuclear Information System (INIS)

Shu, D.; Toellner, T. S.; Alp, E. E.; Maser, J.; Ilavsky, J.; Shastri, S. D.; Lee, P. L.; Narayanan, S.; Long, G. G.

2007-01-01

Unlike traditional kinematic flexure mechanisms, laminar overconstrained weak-link mechanisms provide much higher structure stiffness and stability. Using a laminar structure configured and manufactured by chemical etching and lithography techniques, we are able to design and build linear and rotary weak-link mechanisms with ultrahigh positioning sensitivity and stability for synchrotron radiation applications. Applications of laminar rotary weak-link mechanism include: high-energy-resolution monochromators for inelastic x-ray scattering and x-ray analyzers for ultra-small-angle scattering and powder-diffraction experiments. Applications of laminar linear weak-link mechanism include high-stiffness piezo-driven stages with subnanometer resolution for an x-ray microscope. In this paper, we summarize the recent designs and applications of the laminar weak-link mechanisms at the Advanced Photon Source

77 FR 40413 - Third-Party Provision of Ancillary Services; Accounting and Financial Reporting for New Electric...

Science.gov (United States)

2012-07-09

... Ancillary Services; Accounting and Financial Reporting for New Electric Storage Technologies AGENCY: Federal... Ancillary Services; Accounting and Financial Reporting for New Electric Storage Technologies, 135 FERC ] 61... Commission 18 CFR Parts 35, 37, and 101 Third-Party Provision of Ancillary Services; Accounting and Financial...

Soot Formation in Freely-Propagating Laminar Premixed Flames

Science.gov (United States)

Lin, K.-C.; Hassan, M. I.; Faeth, G. M.

1997-01-01

Soot formation within hydrocarbon-fueled flames is an important unresolved problem of combustion science. Thus, the present study is considering soot formation in freely-propagating laminar premixed flames, exploiting the microgravity environment to simplify measurements at the high-pressure conditions of interest for many practical applications. The findings of the investigation are relevant to reducing emissions of soot and continuum radiation from combustion processes, to improving terrestrial and spacecraft fire safety, and to developing methods of computational combustion, among others. Laminar premixed flames are attractive for studying soot formation because they are simple one-dimensional flows that are computationally tractable for detailed numerical simulations. Nevertheless, studying soot-containing burner-stabilized laminar premixed flames is problematical: spatial resolution and residence times are limited at the pressures of interest for practical applications, flame structure is sensitive to minor burner construction details so that experimental reproducibility is not very good, consistent burner behavior over the lengthy test programs needed to measure soot formation properties is hard to achieve, and burners have poor durability. Fortunately, many of these problems are mitigated for soot-containing, freely-propagating laminar premixed flames. The present investigation seeks to extend work in this laboratory for various soot processes in flames by observing soot formation in freely-propagating laminar premixed flames. Measurements are being made at both Normal Gravity (NG) and MicroGravity (MG), using a short-drop free-fall facility to provide MG conditions.

Use of Ancillary Tests When Determining Brain Death in Pediatric Patients in the United States.

Science.gov (United States)

Lewis, Ariane; Adams, Nellie; Chopra, Arun; Kirschen, Matthew P

2017-10-01

Although pediatric brain death guidelines stipulate when ancillary testing should be used during brain death determination, little is known about the way these recommendations are implemented in clinical practice. We conducted a survey of pediatric intensivists and neurologists in the United States on the use of ancillary testing. Although most respondents noted they only performed an ancillary test if the clinical examination and apnea test could not be completed, 20% of 195 respondents performed an ancillary test for other reasons, including (1) to convince a family that objected to the brain death determination that a patient is truly dead (n = 21), (2) personal preference (n = 14), and (3) institutional requirement (n = 5). Our findings suggest that pediatricians use ancillary tests for a variety of reasons during brain death determination. Medical societies and governmental regulatory bodies must reinforce the need for homogeneity in practice.

Laminar turbulent transition in heated free jet

International Nuclear Information System (INIS)

Krejci, L.; Marsik, F.; Nenicka, V.

1998-01-01

The evolution of heat and mass transfer in the initial region of a transitional plasma plume is investigated and discussed. The results show that these transport processes are controlled and limited by the plume shear layer instability. The process of laminar-turbulent transition is consecutively controlled by the plume core shear layer instability where interrelation of the effective thickness of the shear temperature and density layers play decisive role. When the absolute instability occurs the resonances in the jet and arc chamber must be taken into account. These processes are manifested in three events. Between the first and second phase, there is a maximum of arc heater exit average enthalpy. The other two thresholds occur at maximum and minimum stagnation heat flux from the plume core. It seems that these processes also influence the thermal energy production in the arc chamber cavity. (author)

Quality improvement of melt extruded laminar systems using mixture design.

Science.gov (United States)

Hasa, D; Perissutti, B; Campisi, B; Grassi, M; Grabnar, I; Golob, S; Mian, M; Voinovich, D

2015-07-30

This study investigates the application of melt extrusion for the development of an oral retard formulation with a precise drug release over time. Since adjusting the formulation appears to be of the utmost importance in achieving the desired drug release patterns, different formulations of laminar extrudates were prepared according to the principles of Experimental Design, using a design for mixtures to assess the influence of formulation composition on the in vitro drug release from the extrudates after 1h and after 8h. The effect of each component on the two response variables was also studied. Ternary mixtures of theophylline (model drug), monohydrate lactose and microcrystalline wax (as thermoplastic binder) were extruded in a lab scale vertical ram extruder in absence of solvents at a temperature below the melting point of the binder (so that the crystalline state of the drug could be maintained), through a rectangular die to obtain suitable laminar systems. Thanks to the desirability approach and a reliability study for ensuring the quality of the formulation, a very restricted optimal zone was defined within the experimental domain. Among the mixture components, the variation of microcrystalline wax content played the most significant role in overall influence on the in vitro drug release. The formulation theophylline:lactose:wax, 57:14:29 (by weight), selected based on the desirability zone, was subsequently used for in vivo studies. The plasma profile, obtained after oral administration of the laminar extruded system in hard gelatine capsules, revealed the typical trend of an oral retard formulation. The application of the mixture experimental design associated to a desirability function permitted to optimize the extruded system and to determine the composition space that ensures final product quality. Copyright © 2015 Elsevier B.V. All rights reserved.

Cigarette smoke extract counteracts atheroprotective effects of high laminar flow on endothelial function

Directory of Open Access Journals (Sweden)

Sindy Giebe

2017-08-01

Full Text Available Tobacco smoking and hemodynamic forces are key stimuli in the development of endothelial dysfunction and atherosclerosis. High laminar flow has an atheroprotective effect on the endothelium and leads to a reduced response of endothelial cells to cardiovascular risk factors compared to regions with disturbed or low laminar flow. We hypothesize that the atheroprotective effect of high laminar flow could delay the development of endothelial dysfunction caused by cigarette smoking. Primary human endothelial cells were stimulated with increasing dosages of aqueous cigarette smoke extract (CSEaq. CSEaq reduced cell viability in a dose-dependent manner. The main mediator of cellular adaption to oxidative stress, nuclear factor erythroid 2-related factor 2 (NRF2 and its target genes heme oxygenase (decycling 1 (HMOX1 or NAD(PH quinone dehydrogenase 1 (NQO1 were strongly increased by CSEaq in a dose-dependent manner. High laminar flow induced elongation of endothelial cells in the direction of flow, activated the AKT/eNOS pathway, increased eNOS expression, phosphorylation and NO release. These increases were inhibited by CSEaq. Pro-inflammatory adhesion molecules intercellular adhesion molecule-1 (ICAM1, vascular cell adhesion molecule-1 (VCAM1, selectin E (SELE and chemokine (C-C motif ligand 2 (CCL2/MCP-1 were increased by CSEaq. Low laminar flow induced VCAM1 and SELE compared to high laminar flow. High laminar flow improved endothelial wound healing. This protective effect was inhibited by CSEaq in a dose-dependent manner through the AKT/eNOS pathway. Low as well as high laminar flow decreased adhesion of monocytes to endothelial cells. Whereas, monocyte adhesion was increased by CSEaq under low laminar flow, this was not evident under high laminar flow.This study shows the activation of major atherosclerotic key parameters by CSEaq. Within this process, high laminar flow is likely to reduce the harmful effects of CSEaq to a certain degree. The

Ancillary benefits of climate policy in a small open economy: The case of Sweden

International Nuclear Information System (INIS)

Krook Riekkola, Anna; Ahlgren, Erik O.; Soederholm, Patrik

2011-01-01

It is increasingly recognised that GHG reduction policies can have important ancillary benefits in the form of positive local and regional environmental impacts. The purpose of this paper is to estimate the domestic ancillary pollution benefits of climate policy in Sweden, and investigate how these are affected by different climate policy designs. The latter differ primarily in terms of how the country chooses to meet a specific target and where the necessary emission reductions take place. The analysis relies on simulations within the energy system optimisation model TIMES-Sweden, and focuses on four non-GHG pollutants: Nitrogen Oxides (NO X ), Non Methane Volatile Organic Compounds (NMVOC), inhalable particles (PM 2.5 ), and Sulphur dioxide (SO 2 ). The simulations permit detailed assessments of the respective technology and fuel choices that underlie any net changes in the estimated ancillary effects. The results indicate that the ancillary benefits constitute a far from insignificant share of total system costs, and this share appears to be highest in the scenarios that entail the largest emission reductions domestically. This result reflects the fact that carbon dioxide emission reductions abroad also implies a lost opportunity of achieving substantial domestic welfare gain from the reductions of regional and local environmental pollutants. - Highlights: → We estimate the domestic ancillary pollution benefits of climate policy in Sweden. → These constitute a sizeable share of total system costs. → The ancillary benefits are highest in the policy scenarios that entail the largest emission reductions domestically.

75 FR 14342 - Market-Based Rates for Wholesale Sales of Electric Energy, Capacity and Ancillary Services by...

Science.gov (United States)

2010-03-25

...; Order No. 697-D] Market-Based Rates for Wholesale Sales of Electric Energy, Capacity and Ancillary... affiliates.\\3\\ \\1\\ Market-Based Rates for Wholesale Sales of Electric Energy, Capacity and Ancillary Services...\\ Market-Based Rates for Wholesale Sales of Electric Energy, Capacity and Ancillary Services by Public...

Ancillary obligations as an additional obligation of a limited liability company's member

Directory of Open Access Journals (Sweden)

Marjanski Vladimir Ž.

2016-01-01

Full Text Available Ancillary obligation can be defined as an obligation of a limited liability company's member undertaken through the instrument of incorporation, which can take the form of monetary or non-monetary obligation (usually it is an obligation of a non-monetary character, which has a certain financial value and can be the object of a legally valid obligation. Ancillary obligations, as a contribution to activities of the company, are not regulated in the Law on Companies. The legal nature of this obligation is different from the obligation to make a contribution in money or in kind to a company's assets, to make additional pay-ins or from the landing of funds to the company. Ancillary obligation is an optional and additional obligation of a limited liability company's member and the obligation itself and its contents is defined in the instrument of incorporation. When a limited liability company's member undertakes an ancillary obligation this creates a distinctive relationship between the member and the company, concerning their respective obligations and the legal status of the company, as well as certain consequences derived from those obligations.

A note on high Schmidt number laminar buoyant jets discharged horizontally

International Nuclear Information System (INIS)

Dewan, A.; Arakeri, J.H.; Srinivasan, J.

1992-01-01

This paper reports on a new model, developed for the integral analysis of high Schmidt number (or equivalently high Prandtl number) laminar buoyant jets discharged horizontally. This model assumes top-hat density profile across the inner core of jet and Gaussian velocity profile. Entrainment coefficient corresponding to pure laminar jet has been taken in the analysis. The prediction of the jet trajectory agree well with experimental data in the regions where the jet remains laminar

Morphodynamic modeling of erodible laminar channels.

Science.gov (United States)

Devauchelle, Olivier; Josserand, Christophe; Lagrée, Pierre-Yves; Zaleski, Stéphane

2007-11-01

A two-dimensional model for the erosion generated by viscous free-surface flows, based on the shallow-water equations and the lubrication approximation, is presented. It has a family of self-similar solutions for straight erodible channels, with an aspect ratio that increases in time. It is also shown, through a simplified stability analysis, that a laminar river can generate various bar instabilities very similar to those observed in natural rivers. This theoretical similarity reflects the meandering and braiding tendencies of laminar rivers indicated by F. Métivier and P. Meunier [J. Hydrol. 27, 22 (2003)]. Finally, we propose a simple scenario for the transition between patterns observed in experimental erodible channels.

VOLTTRON-Based System for Providing Ancillary Services with Residential Building Loads

Energy Technology Data Exchange (ETDEWEB)

Jin, Xin

2016-07-01

Ancillary services entail controlled modulation of building equipment to maintain a stable balance of generation and load in the power system. Ancillary services include frequency regulation and contingency reserves, whose acting time ranges from several seconds to several minutes. Many pilot studies have been implemented to use industrial loads to provide ancillary services, and some have explored services from commercial building loads or electric vehicle charging loads. Residential loads, such as space conditioning and water heating, represent a largely untapped resource for providing ancillary services. The residential building sector accounts for a significant fraction of the total electricity use in the United States. Many loads in residential buildings are flexible and could potentially be curtailed or shifted at the request of the grid. However, there are many barriers that prevent residential loads being widely used for ancillary services. One of the major technical barriers is the lack of communication capabilities between end-use devices and the grid. End-use devices need to be able to receive the automatic generation control (AGC) signal from the grid operator and supply certain types of telemetry to verify response. With the advance of consumer electronics, communication-enabled, or 'connected,' residential equipment has emerged to overcome the communication barrier. However, these end-use devices have introduced a new interoperability challenge due to the existence of numerous standards and communication protocols among different end devices. In this paper, we present a VOLTTRON-based system that overcomes these technical challenges and provides ancillary services with residential loads. VOLTTRON is an open-source control and sensing platform for building energy management, facilitating interoperability solutions for end devices. We have developed drivers to communicate and control different types of end devices through standard

Estructuras laminares en España

Directory of Open Access Journals (Sweden)

Coello de Portugal, Fray

1968-02-01

Full Text Available This article deals with three interesting thin shell structures that serve as roofs for churches in various parts of Spain. The excellent functional properties of these shells is worth noting as well as their spectacular aspect and relatively low cost, especially if their complex geometry and striking structural effectiveness are taken into account. The Portuguese architect Fray Coello provided the general pattern of the designs, and the firm Construcciones Laminares, S. L., was responsible for the supervision of the construction, the calculations, plans, details and the actual construction. This paper was submited to lASS, 1967, in Mexico.Se exponen aquí tres interesantes cubiertas laminares para respectivas iglesias situadas en diferentes puntos de la geografía hispana. Se han de resaltar sus magníficos resultados y comportamiento, así como la gran espectacularidad conseguida y su bajo costo relativo, sobre todo a la vista de la plasticidad formal y el dramatismo estructural de las soluciones adoptadas. El arquitecto Fray Coello de Portugal aportó las ideas generales de diseño, encargándose el proyecto, supervisión, cálculo, planos, detalles, e incluso la construcción en algunos casos, a Construcciones Laminares, S. L. Este trabajo fue presentado en la IASS-1967 de México.

Conceptual design for a laminar-flying-wing aircraft

Science.gov (United States)

Saeed, T. I.

The laminar-flying-wing aircraft appears to be an attractive long-term prospect for reducing the environmental impact of commercial aviation. In assessing its potential, a relatively straightforward initial step is the conceptual design of a version with restricted sweep angle. Such a design is the topic of this thesis. Subject to constraints, this research aims to; provide insight into the parameters affecting practical laminar-flow-control suction power requirements; identify a viable basic design specification; and, on the basis of this, an assessment of the fuel efficiency through a detailed conceptual design study. It is shown that there is a minimum power requirement independent of the suction system design, associated with the stagnation pressure loss in the boundary layer. This requirement increases with aerofoil section thickness, but depends only weakly on Mach number and (for a thick, lightly-loaded laminar flying wing) lift coefficient. Deviation from the optimal suction distribution, due to a practical chamber-based architecture, is found to have very little effect on the overall suction coefficient. In the spanwise direction, through suitable choice of chamber depth, the pressure drop due to frictional and inertial effects may be rendered negligible. Finally, it is found that the pressure drop from the aerofoil surface to the pump collector ducts determines the power penalty. To identify the viable basic design specification, a high-level exploration of the laminar flying wing design space is performed. The characteristics of the design are assessed as a function of three parameters: thickness-to-chord ratio, wingspan, and unit Reynolds number. A feasible specification, with 20% thickness-to-chord, 80 m span and a unit Reynolds number of 8 x 106 m-1, is identified; it corresponds to a 187 tonne aircraft which cruises at Mach 0.67 and altitude 22,500 ft, with lift coefficient 0.14. On the basis of this specification, a detailed conceptual design is

Application of laminar flow control to high-bypass-ratio turbofan engine nacelles

Science.gov (United States)

Wie, Y. S.; Collier, F. S., Jr.; Wagner, R. D.

1991-01-01

Recently, the concept of the application of hybrid laminar flow to modern commercial transport aircraft was successfully flight tested on a Boeing 757 aircraft. In this limited demonstration, in which only part of the upper surface of the swept wing was designed for the attainment of laminar flow, significant local drag reduction was measured. This paper addresses the potential application of this technology to laminarize the external surface of large, modern turbofan engine nacelles which may comprise as much as 5-10 percent of the total wetted area of future commercial transports. A hybrid-laminar-flow-control (HLFC) pressure distribution is specified and the corresponding nacelle geometry is computed utilizing a predictor/corrector design method. Linear stability calculations are conducted to provide predictions of the extent of the laminar boundary layer. Performance studies are presented to determine potential benefits in terms of reduced fuel consumption.

Mapping Cortical Laminar Structure in the 3D BigBrain.

Science.gov (United States)

Wagstyl, Konrad; Lepage, Claude; Bludau, Sebastian; Zilles, Karl; Fletcher, Paul C; Amunts, Katrin; Evans, Alan C

2018-07-01

Histological sections offer high spatial resolution to examine laminar architecture of the human cerebral cortex; however, they are restricted by being 2D, hence only regions with sufficiently optimal cutting planes can be analyzed. Conversely, noninvasive neuroimaging approaches are whole brain but have relatively low resolution. Consequently, correct 3D cross-cortical patterns of laminar architecture have never been mapped in histological sections. We developed an automated technique to identify and analyze laminar structure within the high-resolution 3D histological BigBrain. We extracted white matter and pial surfaces, from which we derived histologically verified surfaces at the layer I/II boundary and within layer IV. Layer IV depth was strongly predicted by cortical curvature but varied between areas. This fully automated 3D laminar analysis is an important requirement for bridging high-resolution 2D cytoarchitecture and in vivo 3D neuroimaging. It lays the foundation for in-depth, whole-brain analyses of cortical layering.

Non-laminar flow model for the impedance of a rod-pinch diode

International Nuclear Information System (INIS)

Ottinger, Paul F.; Schumer, Joseph W.; Strasburg, Sean D.; Swanekamp, Stephen B.; Oliver, Bryan V.

2002-01-01

A previous laminar flow model for the rod-pinch diode is extended to include a transverse pressure term to study the effects of non-laminar flow. The non-laminar nature of the flow has a significant impact on the diode impedance. Results show that the introduction of the transverse pressure decreases the diode impedance predicted by the model bringing it into better agreement with experimental data

Exogam with Vamos, Tiara and other ancillary detectors

International Nuclear Information System (INIS)

Lewitowicz, M.; Olivier, L.; Savajols, H.; Catford, W.; Raine, B.; Oliveira, F. de; Perru, O.; Podolyak, Z.; Redon, N.; Bouchez, E.; Simenel, C.; Stanoiu, M.; Lemmon, R.; Rubio, B.; Obertelli, A.; Cederwall, B.; Chapman, R.; Korten, W.; Rubio Barroso, B.

2003-01-01

The aim of this workshop was to discuss the status of experiments at GANIL facility using Exogam with Vamos, Tiara and other ancillary detectors. This document gathers most of the slides that were presented at the workshop, it concerns 8 presentations: 1) the status of Spiral and Spiral-II, 2) the status of Tiara (Tiara array is used for the study of nuclear transfer reactions with radioactive beams in inverse kinematics), 3) data acquisition for the ancillary detectors, 4) the identification of gamma-ray in nuclei around Sm 130 : probing the maximally deformed light rare earth region, 5) the Coulomb excitation of radioactive krypton beams (Kr 76 , Kr 74 ), 6) the influence of weakly bound neutrons on fusion around the Coulomb barrier, 7) single particle transfer on doubly-magic Ni 56 , and 8) the study of N=16 for neutron rich nuclei with Ne 26 (d,p)Ne 27 transfer reaction

Laminar Flame Velocity and Temperature Exponent of Diluted DME-Air Mixture

Science.gov (United States)

Naseer Mohammed, Abdul; Anwar, Muzammil; Juhany, Khalid A.; Mohammad, Akram

2017-03-01

In this paper, the laminar flame velocity and temperature exponent diluted dimethyl ether (DME) air mixtures are reported. Laminar premixed mixture of DME-air with volumetric dilutions of carbon dioxides (CO2) and nitrogen (N2) are considered. Experiments were conducted using a preheated mesoscale high aspect-ratio diverging channel with inlet dimensions of 25 mm × 2 mm. In this method, flame velocities are extracted from planar flames that were stabilized near adiabatic conditions inside the channel. The flame velocities are then plotted against the ratio of mixture temperature and the initial reference temperature. A non-linear power law regression is observed suitable. This regression analysis gives the laminar flame velocity at the initial reference temperature and temperature exponent. Decrease in the laminar flame velocity and increase in temperature exponent is observed for CO2 and N2 diluted mixtures. The addition of CO2 has profound influence when compared to N2 addition on both flame velocity and temperature exponent. Numerical prediction of the similar mixture using a detailed reaction mechanism is obtained. The computational mechanism predicts higher magnitudes for laminar flame velocity and smaller magnitudes of temperature exponent compared to experimental data.

Power system studies of new ancillary services

DEFF Research Database (Denmark)

Hansen, Anca Daniela; Altin, Müfit

The objective of this report is to illustrate and analyse, by means of simulation test cases, the impact of wind power advanced ancillary services, like inertial response (IR), power oscillation damping (POD) and synchronising power (SP) on the power system. Generic models for wind turbine, wind...... power plant and power system are used in the investigation....

Aerodynamic study of a small wind turbine with emphasis on laminar and transition flows

Science.gov (United States)

Niculescu, M. L.; Cojocaru, M. G.; Crunteanu, D. E.

2016-06-01

The wind energy is huge but unfortunately, wind turbines capture only a little part of this enormous green energy. Furthermore, it is impossible to put multi megawatt wind turbines in the cities because they generate a lot of noise and discomfort. Instead, it is possible to install small Darrieus and horizontal-axis wind turbines with low tip speed ratios in order to mitigate the noise as much as possible. Unfortunately, the flow around this wind turbine is quite complex because the run at low Reynolds numbers. Therefore, this flow is usually a mixture of laminar, transition and laminar regimes with bubble laminar separation that is very difficult to simulate from the numerical point of view. Usually, transition and laminar regimes with bubble laminar separation are ignored. For this reason, this paper deals with laminar and transition flows in order to provide some brightness in this field.

Optimal generator bidding strategies for power and ancillary services

Science.gov (United States)

Morinec, Allen G.

As the electric power industry transitions to a deregulated market, power transactions are made upon price rather than cost. Generator companies are interested in maximizing their profits rather than overall system efficiency. A method to equitably compensate generation providers for real power, and ancillary services such as reactive power and spinning reserve, will ensure a competitive market with an adequate number of suppliers. Optimizing the generation product mix during bidding is necessary to maximize a generator company's profits. The objective of this research work is to determine and formulate appropriate optimal bidding strategies for a generation company in both the energy and ancillary services markets. These strategies should incorporate the capability curves of their generators as constraints to define the optimal product mix and price offered in the day-ahead and real time spot markets. In order to achieve such a goal, a two-player model was composed to simulate market auctions for power generation. A dynamic game methodology was developed to identify Nash Equilibria and Mixed-Strategy Nash Equilibria solutions as optimal generation bidding strategies for two-player non-cooperative variable-sum matrix games with incomplete information. These games integrated the generation product mix of real power, reactive power, and spinning reserve with the generators's capability curves as constraints. The research includes simulations of market auctions, where strategies were tested for generators with different unit constraints, costs, types of competitors, strategies, and demand levels. Studies on the capability of large hydrogen cooled synchronous generators were utilized to derive useful equations that define the exact shape of the capability curve from the intersections of the arcs defined by the centers and radial vectors of the rotor, stator, and steady-state stability limits. The available reactive reserve and spinning reserve were calculated given a

Laminar and Turbulent Flow Calculations for the Hifire-5B Flight Test

Science.gov (United States)

2017-11-01

STATES AIR FORCE AFRL-RQ-WP-TP-2017-0172 LAMINAR AND TURBULENT FLOW CALCULATIONS FOR THE HIFIRE-5B FLIGHT TEST Roger L. Kimmel Hypersonic Sciences...stationary instabilities of the three-dimensional flow as the grid becomes finer. It may not be possible to obtain a strictly laminar basic state on a very...fine grid. A basic state solution was desired for the laminar flow calculations, and the oscillations observed in Fig. 3 were judged to be undesirable

Experimental study of transition from laminar to turbulent flow in vertical narrow channel

International Nuclear Information System (INIS)

Wang Chang; Gao Puzhen; Wang Zhanwei; Tan Sichao

2012-01-01

Highlights: ► The effect of wall heating on the laminar to turbulent transition is experimentally studied. ► The flow characteristic demonstrates that heating leads to the delay of transition from laminar to turbulent regimes. ► The heat transfer characteristics also indicates that heating leads to the delay of flow regime transition. - Abstract: Experimental investigation of flow and heat transfer characteristics of a vertical narrow channel with uniform heat flux condition are conducted to analysis the effect of wall heating on the laminar to turbulent transition. The friction factor in the heating condition is compared with that in the adiabatic condition and the results show that wall heating leads to the delay of laminar to turbulent transition. In addition, the heat transfer characteristic indicates that the critical Reynolds number at the point of laminar flow breakdown increases with the increase of fluid temperature difference, and the local Nusselt number at the point of laminar breakdown increases with the increase of the inlet Reynolds number. The analyses of the flow and heat transfer characteristics both indicate that the heating has a stabilizing effect on the water flow at present experimental scale.

Laminar iridium coating produced by pulse current electrodeposition from chloride molten salt

Energy Technology Data Exchange (ETDEWEB)

Zhu, Li’an, E-mail: mr_zla@163.com; Bai, Shuxin; Zhang, Hong; Ye, Yicong

2013-10-01

Due to the unique physical and chemical properties, Iridium (Ir) is one of the most promising oxidation-resistant coatings for refractory materials above 1800 °C in aerospace field. However, the Ir coatings prepared by traditional methods are composed of columnar grains throughout the coating thickness. The columnar structure of the coating is considered to do harm to its oxidation resistance. The laminar Ir coating is expected to have a better high-temperature oxidation resistance than the columnar Ir coating does. The pulse current electrodeposition, with three independent parameters: average current density (J{sub m}), duty cycle (R) and pulse frequency (f), is considered to be a promising method to fabricate layered Ir coating. In this study, laminar Ir coatings were prepared by pulse current electrodeposition in chloride molten salt. The morphology, roughness and texture of the coatings were determined by scanning electron microscope (SEM), profilometer and X-ray diffraction (XRD), respectively. The results showed that the laminar Ir coatings were composed of a nucleation layer with columnar structure and a growth layer with laminar structure. The top surfaces of the laminar Ir coatings consisted of cauliflower-like aggregates containing many fine grains, which were separated by deep grooves. The laminar Ir coating produced at the deposition condition of 20 mA/cm{sup 2} (J{sub m}), 10% (R) and 6 Hz (f) was quite smooth (R{sub a} 1.01 ± 0.09 μm) with extremely high degree of preferred orientation of 〈1 1 1〉, and its laminar structure was well developed with clear boundaries and uniform thickness of sub-layers.

Optimization of the THz radiation from superconductor at non-laminar regime

Energy Technology Data Exchange (ETDEWEB)

Hosseini, Mehdi, E-mail: hosseini@sutech.ac.ir

2016-10-15

Highlights: • The terahertz radiation of a mesa structure at non laminar regime is considered here. • The non-laminarity of this media is modeled. • The equation of vortex motion and electromagnetic field is solved. • The radiated power is obtained and the parameter optimization for maximize the radiated power is done. - Abstract: The THz radiation due to the flux flow in a superconductor slab at non-laminar regime has been investigated and the radiated power spectrum has been calculated. The parameter (τ) is defined to show amount of non-laminarity. The results reveal that for small values of τ, the system radiated at the harmonics of famous washboard frequency. However, for large values of τ, the radiation spectrum will be changed and for extreme values of τ, the peaks will be flat. Therefore the washboard picture is not valid anymore. The results show that the radiation power is optimum for the special value of τ. Also, the results compared with other theoretical and experimental data.

Capabilities and costs for ancillary services provision by wind power plants. Deliverable D 3.1

DEFF Research Database (Denmark)

Faiella, Mariano; Hennig, Tobias; Cutululis, Nicolaos Antonio

This report is the deliverable of the third work package of the REserviceS project and describes the technical options and related costs for the provision of ancillary services specifically from wind energy technologies. It is focused on the set of ancillary services defined in the previous work...

Technical and economic aspects of ancillary services markets in the electric power industry: an international comparison

International Nuclear Information System (INIS)

Raineri, R.; Rios, S.; Schiele, D.

2006-01-01

We present a comparative analysis of technical and economic aspects of ancillary services on the markets of England and Wales, Nordic Countries, California, Argentina, Australia and Spain, comparing the services of voltage control, frequency regulation and system restoration. All the analyzed markets rely on the existence of an administrator of ancillary services, function that leads to the figure of the system operator. Among the services analyzed, the mandatory nature of voltage control and primary frequency regulation stands out, being both the ancillary services with the higher market price and the shortest period of time requirements. In general, the recognized costs of the services correspond to investments operation, maintenance, and opportunity costs. In the provision of these ancillary services, there are no clear preferences for a particular resource allocation mechanism, where mandatory provision, auctions, competitive offers and different time length bilateral contracts are combined

Formation of free round jets with long laminar regions at large Reynolds numbers

Science.gov (United States)

Zayko, Julia; Teplovodskii, Sergey; Chicherina, Anastasia; Vedeneev, Vasily; Reshmin, Alexander

2018-04-01

The paper describes a new, simple method for the formation of free round jets with long laminar regions by a jet-forming device of ˜1.5 jet diameters in size. Submerged jets of 0.12 m diameter at Reynolds numbers of 2000-12 560 are experimentally studied. It is shown that for the optimal regime, the laminar region length reaches 5.5 diameters for Reynolds number ˜10 000 which is not achievable for other methods of laminar jet formation. To explain the existence of the optimal regime, a steady flow calculation in the forming unit and a stability analysis of outcoming jet velocity profiles are conducted. The shortening of the laminar regions, compared with the optimal regime, is explained by the higher incoming turbulence level for lower velocities and by the increase of perturbation growth rates for larger velocities. The initial laminar regions of free jets can be used for organising air curtains for the protection of objects in medicine and technologies by creating the air field with desired properties not mixed with ambient air. Free jets with long laminar regions can also be used for detailed studies of perturbation growth and transition to turbulence in round jets.

Flight tests of a supersonic natural laminar flow airfoil

International Nuclear Information System (INIS)

Frederick, M A; Banks, D W; Garzon, G A; Matisheck, J R

2015-01-01

A flight test campaign of a supersonic natural laminar flow airfoil has been recently completed. The test surface was an 80 inch (203 cm) chord and 40 inch (102 cm) span article mounted on the centerline store location of an F-15B airplane. The test article was designed with a leading edge sweep of effectively 0° to minimize boundary layer crossflow. The test article surface was coated with an insulating material to avoid significant heat transfer to and from the test article structure to maintain a quasi-adiabatic wall. An aircraft-mounted infrared camera system was used to determine boundary layer transition and the extent of laminar flow. The tests were flown up to Mach 2.0 and chord Reynolds numbers in excess of 30 million. The objectives of the tests were to determine the extent of laminar flow at high Reynolds numbers and to determine the sensitivity of the flow to disturbances. Both discrete (trip dots) and 2D disturbances (forward-facing steps) were tested. A series of oblique shocks, of yet unknown origin, appeared on the surface, which generated sufficient crossflow to affect transition. Despite the unwanted crossflow, the airfoil performed well. The results indicate that the sensitivity of the flow to the disturbances, which can translate into manufacturing tolerances, was similar to that of subsonic natural laminar flow wings. (paper)

Application of microgrids in providing ancillary services to the utility grid

International Nuclear Information System (INIS)

Majzoobi, Alireza; Khodaei, Amin

2017-01-01

A microgrid optimal scheduling model is developed in this paper to demonstrate microgrid's capability in offering ancillary services to the utility grid. The application of localized ancillary services is of significant importance to grid operators as the growing proliferation of distributed renewable energy resources, mainly solar generation, is causing major technical challenges in supply-load balance. The proposed microgrid optimal scheduling model coordinates the microgrid net load with the aggregated consumers/prosumers net load in its connected distribution feeder to capture both inter-hour and intra-hour net load variations. In particular, net load variations for three various time resolutions are considered, including hourly ramping, 10-min based load following, and 1-min based frequency regulation. Numerical simulations on a test distribution feeder with one microgrid and several consumers/prosumers indicate the effectiveness of the proposed model and the viability of the microgrid application in supporting grid operation. - Highlights: • Microgrid optimal scheduling for providing ancillary services to the utility grid. • Local management and mitigation of distribution net load variations. • Offering various support services: ramping, load following, frequency regulation. • Proven effectiveness and accuracy in capturing net load variations.

History of Suction-Type Laminar-Flow Control with Emphasis on Flight Resrearch: Monographs in Aerospace History Number 13

Science.gov (United States)

Braslow, A. L.

1999-01-01

The paper contains the following sections: Foreword; Preface; Laminar-Flow Control Concepts and Scope of Monograph; Early Research on Suction-Type Laminar-Flow Control (Research from the 1930s through the War Years; Research from after World War II to the Mid-1960s); Post X-21 Research on Suction-Type Laminar-Flow Control; Status of Laminar-Flow Control Technology in the Mid-1990s; Glossary; Document 1-Aeronautics Panel, AACB, R&D Review, Report of the Subpanel on Aeronautic Energy Conservation/Fuels; Document 2-Report of Review Group on X-21A Laminar Flow Control Program; Document 3-Langley Research Center Announcement, Establishment of Laminar Flow Control Working Group; Document 4-Intercenter Agreement for Laminar Flow Control Leading Edge Glove Flights, LaRC and DFRC; Document 5-Flight Report NLF-144, of AFTIF-111 Aircraft with the TACT Wing Modified by a Natural Laminar Flow Glove; Document 6-Flight Record, F-16XL Supersonic Laminar Flow Control Aircraft; Index; and About the Author.

78 FR 46177 - Third-Party Provision of Ancillary Services; Accounting and Financial Reporting for New Electric...

Science.gov (United States)

2013-07-30

...-Party Provision of Ancillary Services; Accounting and Financial Reporting for New Electric Storage... Financial Reporting for New Electric Storage Technologies, Notice of Proposed Rulemaking, FERC Stats. & Regs... Commission 18 CFR Parts 35 and 101 Third-Party Provision of Ancillary Services; Accounting and Financial...

Cortical laminar necrosis in brain infarcts: chronological changes on MRI

Energy Technology Data Exchange (ETDEWEB)

Komiyama, M. [Department of Neurosurgery, Osaka City General Hospital, 2-13-22, Miyakojima-Hondouri, Miyakojima, Osaka 534 (Japan); Nishikawa, M. [Department of Neurosurgery, Osaka City General Hospital, 2-13-22, Miyakojima-Hondouri, Miyakojima, Osaka 534 (Japan); Yasui, T. [Department of Neurosurgery, Osaka City General Hospital, 2-13-22, Miyakojima-Hondouri, Miyakojima, Osaka 534 (Japan)

1997-07-10

We studied the MRI characteristics of cortical laminar necrosis in ischaemic stroke. We reviewed 13 patients with cortical laminar high signal on T1-weighted images to analyse the chronological changes in signal intensity and contrast enhancement. High-density cortical lesions began to appear on T1-weighted images about 2 weeks after the ictus. At 1-2 months they were prominent. They began to fade from 3 months but could be seen up to 11 months. These cortical lesions showed isointensity or high intensity on T2-weighted images and did not show low intensity at any stage. Contrast enhancement of the laminar lesions was prominent at 1-2 months and became less apparent from 3 months, but could be seen up to 8 months. (orig.). With 6 figs., 1 tab.

Reduced risks and improved economic operation of ancillary services

NARCIS (Netherlands)

Bosch, van den P.P.J.; Jokic, A.; Hermans, R.M.; Frunt, J.; Kling, W.L.; Nobel, Frank; Boonekamp, P.; Boer, de W.W.

2010-01-01

Present arrangements and regulation for ancillary services for power balance in power systems cannot cope with future developments in power systems as the participants do not receive proper incentives for required behaviour. This paper analyzes the consequences of current arrangements for system

Axisymmetric thermoviscoelastoplastic state of branched laminar shells, taking account of transverse-shear and torsional deformation

International Nuclear Information System (INIS)

Galishin, A.Z.

1995-01-01

The nonaxisymmetric thermoelastic stress-strain state (SSS) of branched laminar orthotropic shells was considered; the axisymmetric thermoviscoelastic SSS of branched laminar orthotropic shells was considered; and the axisymmetric thermoviscoelastoplastic SSS of branched laminar isotropic shells was considered, taking into account of the transverse-shear deformation. In the present work, in contrast, the axisymmetric thermoviscoelastoplastic SSS of branched laminar isotropic shells is considered, taking account of transverse-shear and torsional deformation. Layers that are made from orthotropic materials and deform in the elastic region may be present

Regulatory issues associated with closure of the Hanford AX Tank Farm ancillary equipment

International Nuclear Information System (INIS)

Becker, D.L.

1998-01-01

Liquid mixed, high-level radioactive waste has been stored in underground single-shell tanks at the US Department of Energy's (DOE's) Hanford Site. After retrieval of the waste from the single-shell tanks, the DOE will proceed with closure of the tank farm. The 241-AX Tank Farm includes four one-million gallon single-shell tanks in addition to sluice lines, transfer lines, ventilation headers, risers, pits, cribs, catch tanks, buildings, well and associated buried piping. This equipment is classified as ancillary equipment. This document addresses the requirements for regulatory close of the ancillary equipment in the Hanford Site 241-AX Tank Farm. The options identified for physical closure of the ancillary equipment include disposal in place, disposal in place after treatment, excavation and disposal on site in an empty single-shell tank, and excavation and disposal outside the AX Tank Farm. The document addresses the background of the Hanford Site and ancillary equipment in the AX Tank Farm, regulations for decontamination and decommissioning of radioactively contaminated equipment, requirements for the cleanup and disposal of radioactive wastes, cleanup and disposal requirements governing hazardous and mixed waste, and regulatory requirements and issues associated with each of the four physical closure options. This investigation was conducted by the Sandia National Laboratories, Albuquerque, New Mexico, during Fiscal Year 1998 for the Hanford Tanks Initiative Project

MRI of laminar heterotopic grey matter

International Nuclear Information System (INIS)

Vahldiek, G.; Terwey, B.; Hanefeld, F.; Sperner, J.

1990-01-01

In one baby and 2 infants who presented with psychomotor retardation and epilepsy laminar heterotopic grey matter was demonstrated via magnetic resonance imaging. Laminar heterotopia is a rare migrational disorder with bilateral symmetric ribbons of grey matter within the centrum semiovale, separated from ventricular walls and from obviously normal-sized cortex by broad layers of white matter. The heterotopic grey matter has a signal intensity which is isointense compared with that of normal cortex irrespective of image weighting. On account of this signal behaviour differentiation against other white matter diseases is easy. The knowledge of these pathognomonic findings facilitates correct diagnosis, especially during the first and the second year of life, when signal intensities of white and grey matter differ from normal findings because of the occasionally delayed myelination process. Therefore, further diagnostic procedures can be avoided and early counseling of parents is possible. (orig.) [de

Mixed integer non-linear programming and Artificial Neural Network based approach to ancillary services dispatch in competitive electricity markets

International Nuclear Information System (INIS)

Canizes, Bruno; Soares, João; Faria, Pedro; Vale, Zita

2013-01-01

Highlights: • Ancillary services market management. • Ancillary services requirements forecast based on Artificial Neural Network. • Ancillary services clearing mechanisms without complex bids and with complex bids. - Abstract: Ancillary services represent a good business opportunity that must be considered by market players. This paper presents a new methodology for ancillary services market dispatch. The method considers the bids submitted to the market and includes a market clearing mechanism based on deterministic optimization. An Artificial Neural Network is used for day-ahead prediction of Regulation Down, regulation-up, Spin Reserve and Non-Spin Reserve requirements. Two test cases based on California Independent System Operator data concerning dispatch of Regulation Down, Regulation Up, Spin Reserve and Non-Spin Reserve services are included in this paper to illustrate the application of the proposed method: (1) dispatch considering simple bids; (2) dispatch considering complex bids

Accounting for Laminar Run & Trip Drag in Supersonic Cruise Performance Testing

Science.gov (United States)

Goodsell, Aga M.; Kennelly, Robert A.

1999-01-01

An improved laminar run and trip drag correction methodology for supersonic cruise performance testing was derived. This method required more careful analysis of the flow visualization images which revealed delayed transition particularly on the inboard upper surface, even for the largest trip disks. In addition, a new code was developed to estimate the laminar run correction. Once the data were corrected for laminar run, the correct approach to the analysis of the trip drag became evident. Although the data originally appeared confusing, the corrected data are consistent with previous results. Furthermore, the modified approach, which was described in this presentation, extends prior historical work by taking into account the delayed transition caused by the blunt leading edges.

Industrial Demand Management Providing Ancillary Services to the Distribution Grid

DEFF Research Database (Denmark)

Rahnama, Samira; Green, Torben; Lyhne, Casper

2017-01-01

A prominent feature of the future smart grid is the active participation of the consumer side in ancillary service provision. Grid operators procure ancillary services, including regulating power, voltage control, frequency control, and so on, to ensure safe, reliable, and high-quality electricity...... delivery. Consumers' involvement requires new entities and infrastructure. A so-called aggregator has been introduced as a new player to manage the services that are offered by the consumption units. This paper describes an industrial scale experimental setup for evaluating a particular type of aggregator....... The aggregator aims to provide a distribution grid service from industrial thermal loads through a direct control policy. Our specific case studies are a supermarket refrigeration system and an HVac chiller in conjunction with an ice storage, which are virtually connected to the aggregator. Practical results...

Loads Providing Ancillary Services: Review of InternationalExperience-- Technical Appendix: Market Descriptions

Energy Technology Data Exchange (ETDEWEB)

Grayson Heffner, Charles Goldman, Kintner-Meyer, M; Kirby, Brendan

2007-05-01

In this study, we examine the arrangements for andexperiences of end-use loads providing ancillary services (AS) in fiveelectricity markets: Australia, the United Kingdom (UK), the Nordicmarket, and the ERCOT and PJM markets in the United States. Our objectivein undertaking this review of international experience was to identifyspecific approaches or market designs that have enabled customer loads toeffectively deliver various ancillary services (AS) products. We hopethat this report will contribute to the ongoing discussion in the U.S.and elsewhere regarding what institutional and technical developments areneeded to ensure that customer loads can meaningfully participate in allwholesale electricity markets.

Laminar burning velocities of acetone in air at room and elevated temperatures

NARCIS (Netherlands)

Nilsson, E.J.K.; Goey, de L.P.H.; Konnov, A.

2013-01-01

Laminar burning velocities of acetone + air mixtures at initial gas mixture temperatures of 298, 318, 338 and 358 K are reported. Non-stretched flames were stabilized on a perforated plate burner at 1 atm, and laminar burning velocities were determined using the heat flux method, at conditions where

MicroRNA-101 mediates the suppressive effect of laminar shear stress on mTOR expression in vascular endothelial cells

Energy Technology Data Exchange (ETDEWEB)

Chen, Kui; Fan, Wendong; Wang, Xing; Ke, Xiao [Division of Cardiology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080 (China); Wu, Guifu, E-mail: eecpchina@yahoo.com.cn [Key Laboratory on Assisted Circulation, Ministry of Health, Guangzhou 510080 (China); Hu, Chengheng, E-mail: huchenghengpci@yahoo.com.cn [Division of Cardiology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080 (China)

2012-10-12

Highlights: Black-Right-Pointing-Pointer Laminar shear stress upregulates miR-101 expression in vascular endothelial cells. Black-Right-Pointing-Pointer miR-101 represses mTOR expression through a specific 3 Prime UTR binding site. Black-Right-Pointing-Pointer Overexpression of miR-101 inhibits G1/S transition and endothelial cell proliferation. Black-Right-Pointing-Pointer Blockade of miR-101 attenuates the suppressive effect of laminar flow on mTOR expression. -- Abstract: Shear stress associated with blood flow plays an important role in regulating gene expression and cell function in endothelial cells (ECs). MicroRNAs (miRNAs) are highly conserved, small non-coding RNAs that negatively regulate the expression of target genes by binding to the mRNA 3 Prime -untranslated region (3 Prime UTR) at the posttranscriptional level involved in diverse cellular processes. This study demonstrates that microRNA-101 in response to laminar shear stress (LSS) is involved in the flow regulation of gene expression in ECs. qRT-PCR analysis showed that miR-101 expression was significantly upregulated in human umbilical vein endothelial cells (HUVECs) exposed to 12 dyn/cm{sup 2} laminar shear stress for 12 h. We found that transfection of miR-101 significantly decreased the luciferase activity of plasmid reporter containing the 3 Prime UTR of mammalian target of rapamycin (mTOR) gene. Western analysis revealed that the protein level of mTOR was significantly reduced in ECs transfected with miR-101. Furthermore, miR-101 overexpression induced cell cycle arrest at the G1/S transition and suppressed endothelial cell proliferation. Finally, transfection of miR-101 inhibitors attenuated the suppressive effects of LSS on mTOR expression, which identified the efficacy of loss-of-function of miR-101 in laminar flow-treated ECs. In conclusion, we have demonstrated that upregulation of miR-101 in response to LSS contributes to the suppressive effects of LSS on mTOR expression and EC

Measurements of the laminar burning velocity of hydrogen-air premixed flames

Energy Technology Data Exchange (ETDEWEB)

Pareja, Jhon; Burbano, Hugo J. [Science and Technology of Gases and Rational Use of Energy Group, Faculty of Engineering, University of Antioquia, Calle 67 N 53, 108 Bloque 20, 447 Medellin (Colombia); Ogami, Yasuhiro [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan)

2010-02-15

Experimental and numerical studies on laminar burning velocities of hydrogen-air mixtures were performed at standard pressure and room temperature varying the equivalence ratio from 0.8 to 3.0. The flames were generated using a contoured slot-type nozzle burner (4 mm x 10 mm). Measurements of laminar burning velocity were conducted using particle tracking velocimetry (PTV) combined with Schlieren photography. This technique provides the information of instantaneous local burning velocities in the whole region of the flame front, and laminar burning velocities were determined using the mean value of local burning velocities in the region of non-stretch. Additionally, average laminar burning velocities were determined using the angle method and compared with the data obtained with the PTV method. Numerical calculations were also conducted using detailed reaction mechanisms and transport properties. The experimental results from the PTV method are in good agreement with the numerical results at every equivalence ratio of the range of study. Differences between the results obtained with the angle method and those with the PTV method are reasonably small when the effects of flame stretch and curvature are reduced by using a contoured slot-type nozzle. (author)

DRE-Enhanced Swept-Wing Natural Laminar Flow at High Reynolds Numbers

Science.gov (United States)

Malik, Mujeeb; Liao, Wei; Li, Fe; Choudhari, Meelan

2013-01-01

Nonlinear parabolized stability equations and secondary instability analyses are used to provide a computational assessment of the potential use of the discrete roughness elements (DRE) technology for extending swept-wing natural laminar flow at chord Reynolds numbers relevant to transport aircraft. Computations performed for the boundary layer on a natural laminar flow airfoil with a leading-edge sweep angle of 34.6deg, free-stream Mach number of 0.75 and chord Reynolds numbers of 17 x 10(exp 6), 24 x 10(exp 6) and 30 x 10(exp 6) suggest that DRE could delay laminar-turbulent transition by about 20% when transition is caused by stationary crossflow disturbances. Computations show that the introduction of small wavelength stationary crossflow disturbances (i.e., DRE) also suppresses the growth of most amplified traveling crossflow disturbances.

Ictiosis congénita tipo laminar, reporte de un caso.

OpenAIRE

Joaquín Saavedra D.; María José Sierralta S.; Cristian Saavedra D; Vanesa Rivera C; Francisco Cerda C.

2014-01-01

RESUMEN INTRODUCCIÓN: La ictiosis tipo laminar es una enfermedad dermatológica infrecuente perteneciente al grupo de las llamadas genodermatosis. Es una forma de ictiosis congénita que es evidente desde el nacimiento. PRESENTACIÓN DEL CASO: Recién nacido por cesárea, sexo masculino, de 36 semanas de gestación, adecuado para la edad gestacional y con APGAR 8. Antecedentes familiares: padres no consanguíneos y hermano con ictiosis tipo laminar. Luego de nacer es hospital...

Entropy Generation in Steady Laminar Boundary Layers with Pressure Gradients

Directory of Open Access Journals (Sweden)

Donald M. McEligot

2014-07-01

Full Text Available In an earlier paper in Entropy [1] we hypothesized that the entropy generation rate is the driving force for boundary layer transition from laminar to turbulent flow. Subsequently, with our colleagues we have examined the prediction of entropy generation during such transitions [2,3]. We found that reasonable predictions for engineering purposes could be obtained for flows with negligible streamwise pressure gradients by adapting the linear combination model of Emmons [4]. A question then arises—will the Emmons approach be useful for boundary layer transition with significant streamwise pressure gradients as by Nolan and Zaki [5]. In our implementation the intermittency is calculated by comparison to skin friction correlations for laminar and turbulent boundary layers and is then applied with comparable correlations for the energy dissipation coefficient (i.e., non-dimensional integral entropy generation rate. In the case of negligible pressure gradients the Blasius theory provides the necessary laminar correlations.

Transactive Control and Coordination of Distributed Assets for Ancillary Services

Energy Technology Data Exchange (ETDEWEB)

Subbarao, Krishnappa [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fuller, Jason C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kalsi, Karanjit [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Somani, Abhishek [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pratt, Robert G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Widergren, Steven E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chassin, David P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2013-09-18

The need to diversify energy supplies, the need to mitigate energy-related environmental impact, and the entry of electric vehicles in large numbers present challenges and opportunities to power system professionals. Wind and solar power provide many benefits, and to reap the benefits the resulting increased variability—forecasted as well as unforecasted—should be addressed. A majority of states and the District of Columbia, representing over half of the total load, have passed renewable portfolio standards. California’s plans call for 33% renewable energy by 2020. For grid balancing and for meeting reliability standards, ancillary services are needed. The needs for these services are poised to increase significantly. Demand resources are receiving increasing attention as one means of providing the ancillary services. Control and coordination of a large number (~millions) of distributed smart grid assets requires innovative approaches. One such approach is transactive control and coordination (TC2)—a distributed, hierarchical, agent-based incentive and control system. The TC2 paradigm is to create a market-like control system in which participation is voluntary and the participant sets the price for participation. For transactions that are frequent, automation of bids and responses is necessary. Such an approach has been developed and demonstrated at the Pacific Northwest National Laboratory. The devices, typically thermostatically controlled heating, ventilating, and air conditioning (HVAC) loads, send their bids—the quantity of energy they need and, based on the consumer preferences encoded in a simple user interface, the price they are willing to pay. The typical bid period is 5 minutes. By aggregating all the bids, a demand curve is generated by the aggregating entity, and matched with a supply curve or supply constraint. The aggregator transmits the clearing price to the devices. The winning devices proceed to consume the energy they bid for and won

Subcortical laminar heterotopia and lissencephaly in two families: a single X linked dominant gene.

Science.gov (United States)

Pinard, J M; Motte, J; Chiron, C; Brian, R; Andermann, E; Dulac, O

1994-01-01

Neuronal migration disorders can now be recognised by MRI. This paper reports two families in which the mothers had subcortical laminar heterotopia and four of their children had either similar heterotopia (two girls) or severe pachygyria or lissencephaly (two boys). Laminar heterotopia was more evident on MRI T2 weighted images. The patients had mild to severe epilepsy and mental retardation depending on the extent of cortical abnormalities. In these families, subcortical laminar heterotopia, pachygyria, and lissencephaly seem to share the same X linked or autosomal dominant gene. No chromosomal abnormalities, especially of chromosome 17, could be identified. For appropriate genetic counselling of the family of a child with lissencephaly or subcortical laminar heterotopia, MRI should be performed in parents or siblings with mental retardation or epilepsy. Images PMID:8057113

Exploring the ancillary benefits of the Kyoto Protocol for air pollution in Europe

International Nuclear Information System (INIS)

Vuuren, D.P. van; Cofala, J.; Eerens, H.E.; Oostenrijk, R.; Heyes, C.; Klimont, Z.; Elzen, M.G.J. den; Amann, M.

2006-01-01

An integrated approach to climate change and regional air pollution can harvest considerable ancillary benefits in terms of environmental impacts and costs. This is because both problems are caused to a large extent by the same activity (fossil fuel combustion). Substantial ancillary benefits were found for regional air pollution (SO 2 , NO x , VOC and particulate matter) of implementing the Kyoto Protocol (intended to control greenhouse gas emissions) in Europe. For instance, while three different scenarios on Kyoto implementation were found to reduce European CO 2 emissions by 4-7%, they also reduced European emissions of SO 2 by 5-14% compared with a no Kyoto policies case. The magnitude of ancillary benefits depends on how flexible mechanisms and surplus emission allowances are used in meeting the Kyoto targets. The total cost savings for implementing current policies for regional air pollution of the Kyoto Protocol are of an order of 2.5-7 billion Euro. In all cases, this is in the order of half the costs of the climate policy (4-12 billion Euro). Using flexible mechanisms reduces emissions of air pollutants for Europe as a whole even further than domestic implementation (e.g. 10-14% versus 5% for SO 2 emissions), but the reductions are shifted from Western Europe to Central and Eastern Europe and Russia. The use of surplus emission allowances to achieve the Kyoto targets decreases the ancillary benefits, in particular for the latter group of countries (e.g. unprotected area against acidification increases from 1.3 to 1.7 million ha)

Computational Optimization of a Natural Laminar Flow Experimental Wing Glove

Science.gov (United States)

Hartshom, Fletcher

2012-01-01

Computational optimization of a natural laminar flow experimental wing glove that is mounted on a business jet is presented and discussed. The process of designing a laminar flow wing glove starts with creating a two-dimensional optimized airfoil and then lofting it into a three-dimensional wing glove section. The airfoil design process does not consider the three dimensional flow effects such as cross flow due wing sweep as well as engine and body interference. Therefore, once an initial glove geometry is created from the airfoil, the three dimensional wing glove has to be optimized to ensure that the desired extent of laminar flow is maintained over the entire glove. TRANAIR, a non-linear full potential solver with a coupled boundary layer code was used as the main tool in the design and optimization process of the three-dimensional glove shape. The optimization process uses the Class-Shape-Transformation method to perturb the geometry with geometric constraints that allow for a 2-in clearance from the main wing. The three-dimensional glove shape was optimized with the objective of having a spanwise uniform pressure distribution that matches the optimized two-dimensional pressure distribution as closely as possible. Results show that with the appropriate inputs, the optimizer is able to match the two dimensional pressure distributions practically across the entire span of the wing glove. This allows for the experiment to have a much higher probability of having a large extent of natural laminar flow in flight.

Operating Room Environment Control. Part A: a Valve Cannister System for Anesthetic Gas Adsorption. Part B: a State-of-the-art Survey of Laminar Flow Operating Rooms. Part C: Three Laminar Flow Experiments

Science.gov (United States)

Meyer, J. S.; Kosovich, J.

1973-01-01

An anesthetic gas flow pop-off valve canister is described that is airtight and permits the patient to breath freely. Once its release mechanism is activated, the exhaust gases are collected at a hose adapter and passed through activated coal for adsorption. A survey of laminar air flow clean rooms is presented and the installation of laminar cross flow air systems in operating rooms is recommended. Laminar flow ventilation experiments determine drying period evaporation rates for chicken intestines, sponges, and sections of pig stomach.

Diseño de un sistema de generación de chorro de agua de flujo laminar iluminado//Designing a system to generate water jet illuminated laminar flow

Directory of Open Access Journals (Sweden)

Néstor A. Ulloa-Auqui

2015-09-01

Full Text Available Se diseñó y fabricó exitosamente un Sistema de Generación de Chorro de Agua de Flujo Laminar Iluminado, el mismo tiene como finalidad desarrollar destrezas y capacidades en el laboratorio de fluidos cuando se realicen prácticas de variación de caudal para obtener diferentes alturas, alcances y observar como viajan las partículas de agua en un flujo laminar, fenómeno que se produce gracias a la iluminación de todo el chorro con la tecnología de la fibra óptica y un potenciador led RGB.  Los resultados obtenidos permiten realizar proyectos en el área de ornamentación que pueden ser utilizados de manera creativa en parques, hoteles, piscinas y piletas.  El estudio inicia con la determinación de las ecuaciones de cantidad de movimiento, balance de energía y movimiento parabólico que sirvieron para el cálculo hidráulico y selección de la bomba de caudal y boquilla del dispositivo. Palabras clave: flujo laminar, chorro de agua, fibra óptica, boquilla._____________________________________________________________________________AbstractA system to generate water jet illuminated laminar flow was successfully designed and fabricated, the same aims to develop skills and capabilities in the laboratory practices fluids when flow variation for different heights and ranges are made and watch the water particles traveling in laminar flow, phenomenon which occurs by lighting the whole jet technology with fiber optics and a RGB led enhancer.  The results obtained allow perform projects in the area of ornamentation, the same that can be used creatively in parks, hotels, swimming pools and fountains.  The study begins with the determination of the equations of momentum, energy balance and parabolic movement that served to the hydraulic calculation and selection of the pump flow and nozzle device. Key words: flow, laminar, waterjet, optical fiber, nozzle.

Measurement of laminar burning velocities and Markstein lengths of diluted hydrogen-enriched natural gas

Energy Technology Data Exchange (ETDEWEB)

Miao, Haiyan; Jiao, Qi; Huang, Zuohua; Jiang, Deming [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Eng., Xi' an Jiaotong University (China)

2009-01-15

The laminar flame characteristics of natural gas-hydrogen-air-diluent gas (nitrogen/CO{sub 2}) mixtures were studied in a constant volume combustion bomb at various diluent ratios, hydrogen fractions and equivalence ratios. Both unstretched laminar burning velocity and Markstein length were obtained. The results showed that hydrogen fraction, diluent ratio and equivalence ratio have combined influence on laminar burning velocity and flame instability. The unstretched laminar burning velocity is reduced at a rate that is increased with the increase of the diluent ratio. The reduction effect of CO{sub 2} diluent gas is stronger than that of nitrogen diluent gas. Hydrogen-enriched natural gas with high hydrogen fraction can tolerate more diluent gas than that with low hydrogen fraction. Markstein length can either increase or decrease with the increase of the diluent ratio, depending on the hydrogen fraction of the fuel. (author)

An assessment of market and policy barriers for demand response providing ancillary services in U.S. electricity markets

International Nuclear Information System (INIS)

Cappers, Peter; MacDonald, Jason; Goldman, Charles; Ma, Ookie

2013-01-01

An impact of increased variable renewable generation is the need for balancing authorities to procure more ancillary services. While demand response resources are technically capable of providing these services, current experience across the U.S. illustrates they are relatively minor players in most regions. Accessing demand response resources for ancillary services may require a number of changes to policies and common practices at multiple levels. Regional reliability councils must first define ancillary services such that demand response resources may provide them. Once the opportunity exists, balancing authorities define and promulgate rules that set the infrastructure investments and performance attributes of a resource wishing to provide such services. These rules also dictate expected revenue streams which reveal the cost effectiveness of these resources. The regulatory compact between utility and state regulators, along with other statutes and decisions by state policymakers, may impact the interest of demand response program providers to pursue these resources as ancillary service providers. This paper identifies within these broad categories specific market and policy barriers to demand response providing ancillary services in different wholesale and retail environments, with emphasis on smaller customers who must be aggregated through a program provider to meet minimum size requirements for wholesale transactions. - Highlights: • We identify barriers keeping demand response from providing ancillary services. • Institutional, financial and program provider business model barriers exist. • Product definitions and rules do not always accommodate demand response well. • Expected revenues are uncertain and may not exceed required investments costs. • Regulatory compact and state statutes limit opportunities for program providers

Ancillary services provided by PV power plants

Directory of Open Access Journals (Sweden)

Antonio PIERNO

2016-07-01

Full Text Available Renewable energy sources are widely utilized in distributed generation systems, and, recently, they are also considered for providing ancillary services. The paper is focused on PV plants, a survey of the most interesting papers published in the literature in the last decade is reported and the main characteristics of the technical proposals, with their advantages and limits, are evidenced. The results are schematically shown in a table that immediately gives the opportunity to be aware of what was already done, representing a reference tool.

Characteristics of laminar MHD fluid hammer in pipe

International Nuclear Information System (INIS)

Huang, Z.Y.; Liu, Y.J.

2016-01-01

As gradually wide applications of MHD fluid, transportation as well as control with pumps and valves is unavoidable, which induces MHD fluid hammer. The paper attempts to combine MHD effect and fluid hammer effect and to investigate the characteristics of laminar MHD fluid hammer. A non-dimensional fluid hammer model, based on Navier–Stocks equations, coupling with Lorentz force is numerically solved in a reservoir–pipe–valve system with uniform external magnetic field. The MHD effect is represented by the interaction number which associates with the conductivity of the MHD fluid as well as the external magnetic field and can be interpreted as the ratio of Lorentz force to Joukowsky force. The transient numerical results of pressure head, average velocity, wall shear stress, velocity profiles and shear stress profiles are provided. The additional MHD effect hinders fluid motion, weakens wave front and homogenizes velocity profiles, contributing to obvious attenuation of oscillation, strengthened line packing and weakened Richardson annular effect. Studying the characteristics of MHD laminar fluid hammer theoretically supplements the gap of knowledge of rapid-transient MHD flow and technically provides beneficial information for MHD pipeline system designers to better devise MHD systems. - Highlights: • Characteristics of laminar MHD fluid hammer are discussed by simulation. • MHD effect has significant influence on attenuation of wave. • MHD effect strengthens line packing. • MHD effect inhibits Richardson annular effect.

30 CFR 250.207 - What ancillary activities may I conduct?

Science.gov (United States)

2010-07-01

... surveys; or (c) Studies that model potential oil and hazardous substance spills, drilling muds and... 30 Mineral Resources 2 2010-07-01 2010-07-01 false What ancillary activities may I conduct? 250.207 Section 250.207 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR OFFSHORE...

The Turbulent-Laminar Transition on the Rocket Surface During the Injection

Directory of Open Access Journals (Sweden)

I. I. Yurchenko

2014-01-01

Full Text Available The variety of turbulent-laminar transition criteria in such environments as the launch vehicle injection points to the essential influence of spherical nose roughness, which is included in one form or another in the critical Reynolds numbers for a lot of explorers of blunt bodies. Some of researchers of the reentry bodies have founded the correlation functions between the momentum thickness Reynolds number and Max number as the transition criteria.In this article we have considered results of flight tests carried out using launch vehicles to define boundary layer regime on the payload fairing surface. The measurements were carried out using specially designed complex of gages consisted of calorimeters, surface temperature gages, and pressure gages. The turbulent-laminar transition was defined in accordance with the sharp change of calorimeter readings and flow separation pressure gages indication.The universal criterion of turbulent-laminar transition has been identified for blunted payload fairings i.e. Reynolds number Reek based on the boundary layer edge parameters in the sonic point of the payload fairing spherical nose and surface roughness height k, which gives the best correlation of all data of flight experiment conducted to define turbulent-laminar transition in boundary layer. The criterion allows defining time margins when boundary layer regime is turbulent at Reek=20±14 existing on space head surfaces and at Reek=6±5 the boundary layer regime is totally laminar.It was defined that under conditions when there are jointly high background disturbances of free stream flux at operation of main launch vehicle engines and influence of the surface roughness the critical value of Reynolds number is an order-diminished value as compared to the values obtained in wind tunnels and in free flight.It was found that with decreasing of roughness influence in growing boundary layer the flow disturbances evolution wide apart the payload fairing

An investigation of the effects of the propeller slipstream of a laminar wing boundary layer

Science.gov (United States)

Howard, R. M.; Miley, S. J.; Holmes, B. J.

1985-01-01

A research program is in progress to study the effects of the propeller slipstream on natural laminar flow. Flight and wind tunnel measurements of the wing boundary layer have been made using hot-film velocity sensor probes. The results show the boundary layer, at any given point, to alternate between laminar and turbulent states. This cyclic behavior is due to periodic external flow turbulence originating from the viscous wake of the propeller blades. Analytic studies show the cyclic laminar/turbulent boundary layer to result in a significantly lower wing section drag than a fully turbulent boundary layer. The application of natural laminar flow design philosophy yields drag reduction benefits in the slipstream affected regions of the airframe, as well as the unaffected regions.

Analysis of the Impact of Wind Power Participating in Both Energy and Ancillary Services Markets – The Danish Case

DEFF Research Database (Denmark)

Soares, Tiago; Morais, Hugo; Pinson, Pierre

2014-01-01

The impact of a high penetration of wind power generation in power systems motivates need for an assessment of its inte raction with electricity markets. With the continuous evolution of wind turbines technology, wind farms have today the ability to provide certain ancillary services...... with appropriate levels of security and reliability . The participation of wind f arms i n ancillary service market s ought to rely on market designs and offering strategies that satisfy power system needs, as well as their operating characteristics . Here we evaluate the system impact of different offering...... strategies that wind farms employ on ene rgy and ancillary service market. A lready proposed Proportional Wind Reserve Strategy (PWRS) and a Continuo us Wind Reserve Strategy (CWRS) are used to determine the amount of available power for ancillary services. A case study based on real and recent dat...

29 CFR 2550.408b-6 - Statutory exemption for ancillary services by a bank or similar financial institution.

Science.gov (United States)

2010-07-01

....408b-6 Statutory exemption for ancillary services by a bank or similar financial institution. (a) In... service is consistent with sound banking and financial practice, as determined by Federal or State... 29 Labor 9 2010-07-01 2010-07-01 false Statutory exemption for ancillary services by a bank or...

Impact of laminar flow velocity of different acids on enamel calcium loss.

Science.gov (United States)

Attin, T; Becker, K; Wiegand, A; Tauböck, T T; Wegehaupt, F J

2013-03-01

The aim of the study was to evaluate the impact of flow velocity under laminar flow conditions of different acidic solutions on enamel erosion. A total of 240 bovine enamel specimens were prepared and allocated to 30 groups (n = 8 each). Samples of 18 groups were superfused in a flow chamber system with laminar flow behavior using 1 ml of citric acid or hydrochloric acid (HCl) of pH 2.0, 2.6 or 3.0. Flow rates in the sample chamber were adjusted to 10, 60 or 100 μl/min. To simulate turbulent flow behavior, samples of six groups were immersed in 1 ml of the respective solution, which was vortexed (15 min, 600 rpm). For simulating non-agitated conditions, specimens of the remaining six groups were immersed in 1 ml of the respective solution without stirring. Calcium in the solutions, released from the enamel samples, was determined using Arsenazo III method. For acidic solutions of pH 2.6 and 3.0, erosive potential of citric acid was equivalent to that of HCl at a flow of 100 μl/min. The same observation was made for the samples subjected to turbulent conditions at pH 3. At all other conditions, citric acid induced a significantly higher calcium loss than HCl. It is concluded that under slow laminar flow conditions, flow rate variations lead to higher erosive impact of citric acid compared to hydrochloric acid at pH 2.0, but not at pH ≥ 2.6 and increasing laminar flow or turbulent conditions. Erosive enamel dissolution under laminar flow conditions is a complex issue influenced by flow rate and acidic substrate.

Posterior cervical spine arthrodesis with laminar screws. A report of two cases

International Nuclear Information System (INIS)

Nakanishi, Kazuo; Tanaka, Masato; Sugimoto, Yoshihisa; Ozaki, Toshifumi

2007-01-01

We performed fixation using laminar screws in 2 patients in whom lateral mass screws, pedicle screws or transarticular screws could not be inserted. One was a 56-year-old woman who had anterior atlantoaxial subluxation (AAS). When a guide wire was inserted using an imaging guide, the hole bled massively. We thought the re-insertion of a guide wire or screw would thus increase the risk of vascular injury, so we used laminar screws. The other case was an 18-year-old man who had a hangman fracture. Preoperative magnetic resonance angiography showed occlusion of the left vertebral artery. A laminar screw was inserted into the patent side (i.e., the right side of C2). Cervical pedicle screws are the most biomechanically stable screws. However, their use carries a high risk of neurovascular complications during screw insertion, because the cervical pedicle is small and is adjacent laterally to the vertebral artery, medially to the spinal cord, and vertically to the nerve roots. Lateral mass screws are also reported to involve a risk of neurovascular injuries. The laminar screw method was thus thought to be useful, since arterial injuries could thus be avoided and it could also be used as a salvage modality for the previous misinsertion. (author)

Crisis in our hospital kitchens: ancillary staffing levels during an outbreak of food poisoning in a long stay hospital.

Science.gov (United States)

Pollock, A M; Whitty, P M

1990-02-10

An investigation into an outbreak of food poisoning caused by Clostridium perfringens showed evidence of poor food handling by catering staff. The reasons behind this were explored by interviewing catering staff, analysing shifts and rotas, and looking at staff vacancies. Morale was low because of staff shortages resulting from a long term recruitment problem. In consequence staff were working double shifts and often for weeks on end without a day off. The reasons for the recruitment problem included the difficulty of recruiting semiskilled labour from a middle class area, low wages, lack of management support, and the poor image of the hospital as a place of work. Similar factors affect the recruitment and retention of ancillary staff nationally. The NHS has a poor record as an employer of ancillary staff, paying lower wages than other organisations for equivalent posts. Competitive tendering has further worsened the position of ancillary staff, with the result that good quality of care and service has often not been achieved. The NHS Review, with its emphasis on quality of care, makes no mention of ancillary staff. Yet high standards of ancillary provision are essential if further outbreaks of food poisoning in hospitals are to be prevented.

Ocean Surface Topography Mission (OSTM) /Jason-2: Ancillary Files (NODC Accession 0044982)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains the data descriptions for the OSTM/Jason-2 Ancillary data files, which is served through the NOAA/NESDIS Comprehensive Large Array-data...

Transport coefficients for laminar and turbulent flow through a four-cusp channel

International Nuclear Information System (INIS)

Souza Dutra, A. de; Parise, J.A.R.; Souza Mendes, P.R. de.

1986-01-01

The heat transfer coefficients for laminar and turbulent flow in a four-cusp channel were determined. A numerical solution was developed for laminar flow an and experimental study for turbulent flow was carried out. Systematic variations of the Reynolds number were done in the range 900-30000. The results show that the heat transfer coefficients for the four-cusp channel are much lower than the coefficients for the circular tube. (author) [pt

Laminar shear stress inhibits endothelial cell metabolism via KLF2-mediated repression of PFKFB3

NARCIS (Netherlands)

Doddaballapur, Anuradha; Michalik, Katharina M.; Manavski, Yosif; Lucas, Tina; Houtkooper, Riekelt H.; You, Xintian; Chen, Wei; Zeiher, Andreas M.; Potente, Michael; Dimmeler, Stefanie; Boon, Reinier A.

2015-01-01

Cellular metabolism was recently shown to regulate endothelial cell phenotype profoundly. Whether the atheroprotective biomechanical stimulus elicited by laminar shear stress modulates endothelial cell metabolism is not known. Here, we show that laminar flow exposure reduced glucose uptake and

Ancillary Frequency Control of Direct Drive Full-Scale Converter Based Wind Power Plants

DEFF Research Database (Denmark)

Hu, Weihao; Su, Chi; Fang, Jiakun

2013-01-01

This paper presents a simulation model of a wind power plant based on a MW-level variable speed wind turbine with a full-scale back-to-back power converter developed in the simulation tool of DIgSILENT Power Factory. Three different kinds of ancillary frequency control strategies, namely inertia...... control strategies are effective means for providing ancillary frequency control of variable speed wind turbines with full-scale back-to-back power converters....... emulation, primary frequency control and secondary frequency control, are proposed in order to improve the frequency stability of power systems. The modified IEEE 39-bus test system with a large-scale wind power penetration is chosen as the studied power system. Simulation results show that the proposed...

Ancillary services and optimal household energy management with photovoltaic production

International Nuclear Information System (INIS)

Clastres, C.; Ha Pham, T.T.; Wurtz, F.; Bacha, S.

2010-01-01

This article presents a project designed to increase the monetary value of photovoltaic (PV) solar production for residential applications. To contribute to developing new functionalities for this type of PV system and an efficient control system for optimising its operation, this article explains how the proposed system could contract to provide ancillary services, particularly the supply of active power services. This provision of service by a PV-based system for domestic applications, not currently available, has prompted a market design proposal related to the distribution system. The mathematical model for calculating the system's optimal operation (sources, load and exchanges of power with the grid) results in a linear mix integer optimisation problem in which the objective is to maximise the profits achieved by taking part in the electricity market. Our approach is illustrated in a case study. PV producers could gain by taking part in the markets for balancing power or ancillary services despite the negative impact on profit of several types of uncertainty, notably the intermittent nature of the PV source.

Study on laminar burning velocity of syngas-air premixed flames in various mixing conditions

International Nuclear Information System (INIS)

Lee, Kee Man; Jeong, Byeong Gyu; Lee, Seung Ro

2015-01-01

The laminar burning velocity of syngas-air premixed flames was measured with various equivalence ratios from 0.5 to 5.0 and a mole fraction of H 2 from 0.05 to 0.75. The laminar burning velocity was experimentally determined using a Bunsen flame according to the cone angle and surface area methods. A premixed code with a USC-II detailed reaction mechanism was used for the numerical calculations to predict the laminar burning velocity and to examine the relationship between the burning velocity enhancement and the hydrogen-related reactions. The results indicate that an appropriate method for the measurement of laminar burning velocity is necessary in the H 2 /CO/air syngas premixed flame. In addition, the burning velocity linearly increased with the increase of the H 2 mole fraction in the syngas mixture, although the burning velocity of H 2 was 10 times larger than that of CO. This result is attributed to the rapid production of H-radicals at the early stage of combustion. Furthermore, the predicted mole fractions of H and OH radicals increased with the increase of H 2 mole fraction for a lean syngas mixture. However, the mole fraction of OH radicals, an indicator of heat release rate, decreased for rich syngas mixture, resulting in a reduction of the laminar burning velocity, even with an increase of the H 2 mole fraction.

Theoretical research on laminar friction resistance in tubes in rolling motion

International Nuclear Information System (INIS)

Yan Binghuo; Yu Lei; Yang Yanhua

2010-01-01

The model of laminar flow in tubes in rolling motion is established. The dimensionless correlation of velocity is derived, and the correlation of frictional resistance coefficient is also obtained. Of all the additional forces, only the tangential force effects on the flow. The effect of centrifugal and Coriolis forces on the flow is counteracted. The correlation of average frictional resistance coefficient is the same with that of no rolling motion. The effect of rolling motion on frictional resistance coefficient of laminar flow diminishes with the increase of Reynolds number. (authors)

Laminar flow and convective transport processes scaling principles and asymptotic analysis

CERN Document Server

Brenner, Howard

1992-01-01

Laminar Flow and Convective Transport Processes: Scaling Principles and Asymptotic Analysis presents analytic methods for the solution of fluid mechanics and convective transport processes, all in the laminar flow regime. This book brings together the results of almost 30 years of research on the use of nondimensionalization, scaling principles, and asymptotic analysis into a comprehensive form suitable for presentation in a core graduate-level course on fluid mechanics and the convective transport of heat. A considerable amount of material on viscous-dominated flows is covered.A unique feat

Impact of advanced wind power ancillary services on power system

DEFF Research Database (Denmark)

Hansen, Anca Daniela; Altin, Müfit

The objective of this report is to illustrate and analyse, by means of simulation test cases, the impact of wind power advanced ancillary services, like inertial response (IR), power oscillation damping (POD) and synchronising power (SP) on the power system. Generic models for wind turbine, wind...... power plant and power system are used in the investigation....

Forced underwater laminar flows with active magnetohydrodynamic metamaterials

Science.gov (United States)

Culver, Dean; Urzhumov, Yaroslav

2017-12-01

Theory and practical implementations for wake-free propulsion systems are proposed and proven with computational fluid dynamic modeling. Introduced earlier, the concept of active hydrodynamic metamaterials is advanced by introducing magnetohydrodynamic metamaterials, structures with custom-designed volumetric distribution of Lorentz forces acting on a conducting fluid. Distributions of volume forces leading to wake-free, laminar flows are designed using multivariate optimization. Theoretical indications are presented that such flows can be sustained at arbitrarily high Reynolds numbers. Moreover, it is shown that in the limit Re ≫102 , a fixed volume force distribution may lead to a forced laminar flow across a wide range of Re numbers, without the need to reconfigure the force-generating metamaterial. Power requirements for such a device are studied as a function of the fluid conductivity. Implications to the design of distributed propulsion systems underwater and in space are discussed.

Surface Runoff in Watershed Modeling—Turbulent or Laminar Flows?

Directory of Open Access Journals (Sweden)

Mark E. Grismer

2016-05-01

Full Text Available Determination of overland sheet flow depths, velocities and celerities across the hillslope in watershed modeling is important towards estimation of surface storage, travel times to streams and soil detachment rates. It requires careful characterization of the flow processes. Similarly, determination of the temporal variation of hillslope-riparian-stream hydrologic connectivity requires estimation of the shallow subsurface soil hydraulic conductivity and soil-water retention (i.e., drainable porosities parameters. Field rainfall and runoff simulation studies provide considerable information and insight into these processes; in particular, that sheet flows are likely laminar and that shallow hydraulic conductivities and storage can be determined from the plot studies. Here, using a 1 m by 2 m long runoff simulation flume, we found that for overland flow rates per unit width of roughly 30–60 mm2/s and bedslopes of 10%–66% with varying sand roughness depths that all flow depths were predicted by laminar flow equations alone and that equivalent Manning’s n values were depth dependent and quite small relative to those used in watershed modeling studies. Even for overland flow rates greater than those typically measured or modeled and using Manning’s n values of 0.30–0.35, often assumed in physical watershed model applications for relatively smooth surface conditions, the laminar flow velocities were 4–5 times greater, while the laminar flow depths were 4–5 times smaller. This observation suggests that travel times, surface storage volumes and surface shear stresses associated with erosion across the landscape would be poorly predicted using turbulent flow assumptions. Filling the flume with fine sand and conducting runoff studies, we were unable to produce sheet flow, but found that subsurface flows were onflow rate, soil depth and slope dependent and drainable porosities were only soil depth and slope dependent. Moreover, both the sand

Provision of enhanced ancillary services from wind power plants - Examples and challenges

DEFF Research Database (Denmark)

Hansen, Anca Daniela; Altin, Müfit; Iov, Florin

2016-01-01

Emphasis in this article is on the power system impact of wind power plants capability to provide enhanced ancillary services, i.e. temporary frequency response (TFR) and power oscillation damping (POD). The main objective of the article is to analyze and justify the challenges in the use of TFR...... and POD from wind power plants (WPPs). The study is conducted with an aggregated wind power plant model which is integrated into a generic power system model, specifically designed to assess the targeted ancillary services in a relatively simple, but still relevant environment. Various case studies...... with different wind power penetration levels are considered. The study shows that WPPs can provide additional control features such as TFR and POD to enhance the stability of power systems with large share of wind power. Nevertheless, the results illustrate that the power system stability can be potentially...

The TIGRESS Integrated Plunger ancillary systems for electromagnetic transition rate studies at TRIUMF

International Nuclear Information System (INIS)

Voss, P.; Henderson, R.; Andreoiu, C.; Ashley, R.; Austin, R.A.E.; Ball, G.C.; Bender, P.C.; Bey, A.; Cheeseman, A.; Chester, A.; Cross, D.S.; Drake, T.E.; Garnsworthy, A.B.; Hackman, G.; Holland, R.; Ketelhut, S.; Kowalski, P.; Krücken, R.; Laffoley, A.T.; Leach, K.G.

2014-01-01

The TIGRESS Integrated Plunger device is a new experimental tool for nuclear structure investigations via gamma-ray spectroscopy with post-accelerated beams from the ISAC-II facility at TRIUMF. Several ancillary detection systems integral to the device's capabilities for charged-particle tagging and light-ion identification following a variety of nuclear reaction mechanisms have been constructed and characterized. In particular, a silicon PIN diode wall, an annular silicon segmented detector, and a CsI(Tl) scintillator wall have together enabled particle-gamma correlations for reaction channel selectivity and precision kinematic reconstruction in recent measurements. We highlight the construction, characteristics, and implementation of the device's ancillary detectors as they enable a rich set of electromagnetic transition rate measurements via Doppler-shift lifetime techniques and low-energy Coulomb excitation

Energy fluxes and spectra for turbulent and laminar flows

KAUST Repository

Verma, Mahendra K.

2017-05-14

Two well-known turbulence models to describe the inertial and dissipative ranges simultaneously are by Pao~[Phys. Fluids {\\\\bf 8}, 1063 (1965)] and Pope~[{\\\\em Turbulent Flows.} Cambridge University Press, 2000]. In this paper, we compute energy spectrum $E(k)$ and energy flux $\\\\Pi(k)$ using spectral simulations on grids up to $4096^3$, and show consistency between the numerical results and predictions by the aforementioned models. We also construct a model for laminar flows that predicts $E(k)$ and $\\\\Pi(k)$ to be of the form $\\\\exp(-k)$, and verify the model predictions using numerical simulations. The shell-to-shell energy transfers for the turbulent flows are {\\\\em forward and local} for both inertial and dissipative range, but those for the laminar flows are {\\\\em forward and nonlocal}.

Study on laminar burning velocity of syngas-air premixed flames in various mixing conditions

Energy Technology Data Exchange (ETDEWEB)

Lee, Kee Man; Jeong, Byeong Gyu [Sunchon National University, Suncheon (Korea, Republic of); Lee, Seung Ro [Chonbuk National University, Jeonju (Korea, Republic of)

2015-07-15

The laminar burning velocity of syngas-air premixed flames was measured with various equivalence ratios from 0.5 to 5.0 and a mole fraction of H{sub 2} from 0.05 to 0.75. The laminar burning velocity was experimentally determined using a Bunsen flame according to the cone angle and surface area methods. A premixed code with a USC-II detailed reaction mechanism was used for the numerical calculations to predict the laminar burning velocity and to examine the relationship between the burning velocity enhancement and the hydrogen-related reactions. The results indicate that an appropriate method for the measurement of laminar burning velocity is necessary in the H{sub 2}/CO/air syngas premixed flame. In addition, the burning velocity linearly increased with the increase of the H{sub 2} mole fraction in the syngas mixture, although the burning velocity of H{sub 2} was 10 times larger than that of CO. This result is attributed to the rapid production of H-radicals at the early stage of combustion. Furthermore, the predicted mole fractions of H and OH radicals increased with the increase of H{sub 2} mole fraction for a lean syngas mixture. However, the mole fraction of OH radicals, an indicator of heat release rate, decreased for rich syngas mixture, resulting in a reduction of the laminar burning velocity, even with an increase of the H{sub 2} mole fraction.

An examination of ongoing trends in airline ancillary revenues

OpenAIRE

Warnock-Smith, David; O'Connell, John Frankie; Maleki, Mahnaz

2015-01-01

The airline industry seems permanently embedded in producing thin margins and continuously combatting downward pressure on yields. To perpetuate the problem, the industry remains eclipsed with high cost structures and low barriers to entry. However, a new sizzling concept continues to counterbalance these effects in the form of ancillary revenues. Globally, these revenues have increased by 121% from 2010 to 2014 – and the trend is set to continue as carriers are quickly implementing structura...

Mobile bank conditions for laminar microrivers

OpenAIRE

Devauchelle , Olivier; Josserand , Christophe; Lagrée , Pierre-Yves; Zaleski , Stéphane

2008-01-01

International audience; The present study aims to establish a simple mechanistic model for river bank erosion. Recent experiments demonstrate that small-scale laminar flumes can develop erosion structures similar to those encountered in Nature. From the Saint-Venant Equations, a classical sediment transport law and a simple avalanche model, it is shown that bank failure caused by flow erosion can be represented through simple boundary conditions. These conditions are able to deal with the wat...

CO{sub 2} mitigation costs and ancillary benefits in the Nordic countries, the UK and Ireland: A survey

Energy Technology Data Exchange (ETDEWEB)

Kverndokk, Snorre; Rosendahl, Knut Einar

2000-07-01

This paper provides a survey of top-down modelling studies on mitigation costs and ancillary benefits in the Nordic countries, the UK and Ireland. Special emphasis is put on results concerning revenue recycling, double dividend, distributional effects and ancillary benefits. According to the papers surveyed, modest emissions restrictions as those given by the Kyoto Protocol, can be met without substantial costs for the countries studied. (Author)

Discrete-Roughness-Element-Enhanced Swept-Wing Natural Laminar Flow at High Reynolds Numbers

Science.gov (United States)

Malik, Mujeeb; Liao, Wei; Li, Fei; Choudhari, Meelan

2015-01-01

Nonlinear parabolized stability equations and secondary-instability analyses are used to provide a computational assessment of the potential use of the discrete-roughness-element technology for extending swept-wing natural laminar flow at chord Reynolds numbers relevant to transport aircraft. Computations performed for the boundary layer on a natural-laminar-flow airfoil with a leading-edge sweep angle of 34.6 deg, freestream Mach number of 0.75, and chord Reynolds numbers of 17 × 10(exp 6), 24 × 10(exp 6), and 30 × 10(exp 6) suggest that discrete roughness elements could delay laminar-turbulent transition by about 20% when transition is caused by stationary crossflow disturbances. Computations show that the introduction of small-wavelength stationary crossflow disturbances (i.e., discrete roughness element) also suppresses the growth of most amplified traveling crossflow disturbances.

An integrated pan-European ancillary services market for frequency control

International Nuclear Information System (INIS)

Scherer, Marc; Zima, Marek; Andersson, Göran

2013-01-01

Real-time balancing of mismatches between consumption and production is one of the key elements for the secure operation of power systems. This takes place within the framework of ancillary services managed by respective national transmission system operating companies. The objective of this paper is to investigate the option of one integrated pan-European ancillary services market. Our contribution is twofold: quantifying the potential benefit of such an option and outlining a possible approach to such an option highlighting its positive properties as well as risks and challenges. In several recently published considerations of pan-European electricity supply models this topic has not been adequately addressed, but we believe it is one of the crucial subjects in shaping the future electricity supply in Europe. -- Author-Highlights: •We investigated the option of a one-area market for frequency control in Continental Europe. •For the current situation a centralised approach may lead to a significant reduction of control reserves. •In the long run it is a possibility to avoid a tremendous increase of needed control reserves. •The implementation of an integrated market is not to be underestimated

Survey of U.S. Ancillary Services Markets

Energy Technology Data Exchange (ETDEWEB)

Zhou, Zhi; Levin, Todd; Conzelmann, Guenter

2016-06-01

In addition to providing energy to end-consumers, power system operators are also responsible for ensuring system reliability. To this end, power markets maintain an array of ancillary services to ensure that it is always possible to balance the supply and demand for energy in real-time. A subset of these ancillary services are commonly procured through market-based mechanisms: namely, Regulation, Spinning, and Non-spinning Reserves. Regulation Reserves are maintained to respond to supply/demand imbalances over short time frames, typically on the order of several seconds to one minute. Resources that provide Regulation Reserves adjust their generation or load levels in response to automatic generation control (AGC) signals provided by the system operator. Contingency reserves are maintained to provide additional generation capacity in the event that load increases substantially or supply side resources reduce their output or are taken offline. The reserves are typically segmented into two categories, 1) Spinning or Synchronized Reserves that are provided by generation units that are actively generating and have the ability to increase or decrease their output, 2) Non-spinning or Non-synchronized Reserves that are provided by generation resources that are not actively generating, but are able to start up and provide generation within a specified timeframe. Contingency reserves typically have response times on the order of ten to 30 minutes and can also be provided by demand-side resources that are capable of reducing their load. There are seven distinct power markets in the United States, each operated by a Regional Transmission Operator (RTO) or Independent System Operator (ISO) that operates the transmission system in its territory, operates markets for energy and ancillary services, and maintains system reliability. Each power market offers its own set of ancillary services, and precise definitions, requirements, and market mechanisms differ between markets

Influence of Wind Plant Ancillary Voltage Control on System Small Signal Stability

DEFF Research Database (Denmark)

Su, Chi; Chen, Zhe

2012-01-01

As a common tendency, large-scale wind farms are increasingly connected to the transmission system of modern power grids. This introduces some new challenges to the connected power systems, and the transmission system operators (TSOs) have to put some new requirements as part of the grid codes...... on the integration of wind farms. One common requirement to wind farms is the function of system voltage control which can be implemented in the grid-side convertor controller of a variable speed wind turbine. This ancillary voltage control provided by wind farms could have some influence on the system small signal...... stability. This paper implements an ancillary voltage control strategy on a direct-drive-full-convertor-based wind farm and studies its influence on the damping ratio values of the dominant oscillation mode within the connected power system. All the calculations and simulations are conducted in DIg...

Simulated annealing to handle energy and ancillary services joint management considering electric vehicles

DEFF Research Database (Denmark)

Sousa, Tiago M; Soares, Tiago; Morais, Hugo

2016-01-01

The massive use of distributed generation and electric vehicles will lead to a more complex management of the power system, requiring new approaches to be used in the optimal resource scheduling field. Electric vehicles with vehicle-to-grid capability can be useful for the aggregator players...... in the mitigation of renewable sources intermittency and in the ancillary services procurement. In this paper, an energy and ancillary services joint management model is proposed. A simulated annealing approach is used to solve the joint management for the following day, considering the minimization...... of the aggregator total operation costs. The case study considers a distribution network with 33-bus, 66 distributed generation and 2000 electric vehicles. The proposed simulated annealing is matched with a deterministic approach allowing an effective and efficient comparison. The simulated annealing presents...

Coordinated Control Scheme for Ancillary Services from Offshore Wind Power Plants to AC and DC Grids

DEFF Research Database (Denmark)

Sakamuri, Jayachandra N.; Altin, Müfit; Hansen, Anca Daniela

2016-01-01

This paper proposes a new approach of providing ancillary services to AC and DC grids from offshore wind power plants (OWPPs), connected through multi-terminal HVDC network. A coordinated control scheme where OWPP’s AC grid frequency modulated according to DC grid voltage variations is used...... to detect and provide the ancillary service requirements of both AC and DC grids, is proposed in this paper. In particular, control strategies for onshore frequency control, fault ridethrough support in the onshore grid, and DC grid voltage control are considered. The proposed control scheme involves only...

EX1606 Dive05 Ancillary Data Collection including reports, kmls, spreadsheets, and data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1606: CAPSTONE Wake Island...

EX1606 Dive04 Ancillary Data Collection including reports, kmls, spreadsheets, and data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1606: CAPSTONE Wake Island...

EX1606 Dive13 Ancillary Data Collection including reports, kmls, spreadsheets, and data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1606: CAPSTONE Wake Island...

EX1606 Dive09 Ancillary Data Collection including reports, kmls, spreadsheets, and data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1606: CAPSTONE Wake Island...

EX1606 Dive10 Ancillary Data Collection including reports, kmls, spreadsheets, and data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1606: CAPSTONE Wake Island...

77 FR 25105 - Reporting of Ancillary Airline Passenger Revenues

Science.gov (United States)

2012-04-27

...This document announces a public meeting on a Notice of Proposed Rulemaking (NPRM) issued on July 15, 2011. The NPRM proposed changes regarding reporting of airline ancillary passenger revenues, computation of mishandled baggage rates, and collection of separate statistics for mishandled wheelchairs and scooters used by passengers with disabilities. During the public meeting, DOT staff will provide a summary of the proposals in the NPRM and seek input on costs and benefits associated with the implementation of the proposals.

Passive Flap Actuation by Reversing Flow in Laminar Boundary Layer Separation

Science.gov (United States)

Parsons, Chase; Lang, Amy; Santos, Leo; Bonacci, Andrew

2017-11-01

Reducing the flow separation is of great interest in the field of fluid mechanics in order to reduce drag and improve the overall efficiency of aircraft. This project seeks to investigate passive flow control using shark inspired microflaps in laminar boundary layer separation. This study aims to show that whether a flow is laminar or turbulent, laminar and 2D or turbulent and 3D, microflaps actuated by reversing flow is a robust means of controlling flow separation. In order to generate a controlled adverse pressure gradient, a rotating cylinder induces separation at a chosen location on a flat plate boundary layer with Re above 10000. Within this thick boundary layer, digital particle image velocimetry is used to map the flow. This research can be used in the future to better understand the nature of the bristling shark scales and its ability to passively control separation. Results show that microflaps successfully actuated due to backflow and that this altered the formation of flow separation. I would like to thank the NSF for REU Grant EEC 1659710 and the Army Research Office for funding this project.

Towards a unified theory of neocortex: laminar cortical circuits for vision and cognition.

Science.gov (United States)

Grossberg, Stephen

2007-01-01

A key goal of computational neuroscience is to link brain mechanisms to behavioral functions. The present article describes recent progress towards explaining how laminar neocortical circuits give rise to biological intelligence. These circuits embody two new and revolutionary computational paradigms: Complementary Computing and Laminar Computing. Circuit properties include a novel synthesis of feedforward and feedback processing, of digital and analog processing, and of preattentive and attentive processing. This synthesis clarifies the appeal of Bayesian approaches but has a far greater predictive range that naturally extends to self-organizing processes. Examples from vision and cognition are summarized. A LAMINART architecture unifies properties of visual development, learning, perceptual grouping, attention, and 3D vision. A key modeling theme is that the mechanisms which enable development and learning to occur in a stable way imply properties of adult behavior. It is noted how higher-order attentional constraints can influence multiple cortical regions, and how spatial and object attention work together to learn view-invariant object categories. In particular, a form-fitting spatial attentional shroud can allow an emerging view-invariant object category to remain active while multiple view categories are associated with it during sequences of saccadic eye movements. Finally, the chapter summarizes recent work on the LIST PARSE model of cognitive information processing by the laminar circuits of prefrontal cortex. LIST PARSE models the short-term storage of event sequences in working memory, their unitization through learning into sequence, or list, chunks, and their read-out in planned sequential performance that is under volitional control. LIST PARSE provides a laminar embodiment of Item and Order working memories, also called Competitive Queuing models, that have been supported by both psychophysical and neurobiological data. These examples show how

Effects of hydrogen addition and nitrogen dilution on the laminar flame characteristics of premixed methane-air flames

Energy Technology Data Exchange (ETDEWEB)

Tahtouh, T.; Halter, F.; Mounaim-Rousselle, C. [Institut PRISME, Universite d' Orleans, 8 rue Leonard de Vinci-45072, Orleans Cedex 2 (France); Samson, E. [PSA Peugeot Citroen (France)

2009-10-15

The effect of hydrogen addition and nitrogen dilution on laminar flame characteristics was investigated. The spherical expanding flame technique, in a constant volume bomb, was employed to extract laminar flame characteristics. The mole fraction of hydrogen in the methane-hydrogen mixture was varied from 0 to 1 and the mole fraction of nitrogen in the total mixture (methane-hydrogen-air-diluent) from 0 to 0.35. Measurements were performed at an initial pressure of 0.1 MPa and an initial temperature of 300 K. The mixtures investigated were under stoichiometric conditions. Based on experimental measurements, a new correlation for calculating the laminar burning velocity of methane-hydrogen-air-nitrogen mixtures is proposed. The laminar burning velocity was found to increase linearly with hydrogen mass fraction for all dilution ratios while the burned gas Markstein length decreases with the increase in hydrogen amount in the mixture except for high hydrogen mole fractions (>0.6). Nitrogen dilution has a nonlinear reducing effect on the laminar burning velocity and an increasing effect on the burned gas Markstein length. The experimental results and the proposed correlation obtained are in good agreement with literature values. (author)

Trace Metal and Ancillary Data in Puget Sound, 1980 - 1986 (NODC Accession 9100153)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — In first of three data reports on the trace metal and ancillary data in Puget Sound and its watershed (Paulson et al., 1991a), all water column, sediment, and...

Energy fluxes and spectra for turbulent and laminar flows

KAUST Repository

Verma, Mahendra K.; Kumar, Abhishek; Kumar, Praveen; Barman, Satyajit; Chatterjee, Anando G.; Samtaney, Ravi

2017-01-01

spectrum $E(k)$ and energy flux $\\Pi(k)$ using spectral simulations on grids up to $4096^3$, and show consistency between the numerical results and predictions by the aforementioned models. We also construct a model for laminar flows that predicts $E(k

A Laminar Organization for Selective Cortico-Cortical Communication

Directory of Open Access Journals (Sweden)

Rinaldo D. D’Souza

2017-08-01

Full Text Available The neocortex is central to mammalian cognitive ability, playing critical roles in sensory perception, motor skills and executive function. This thin, layered structure comprises distinct, functionally specialized areas that communicate with each other through the axons of pyramidal neurons. For the hundreds of such cortico-cortical pathways to underlie diverse functions, their cellular and synaptic architectures must differ so that they result in distinct computations at the target projection neurons. In what ways do these pathways differ? By originating and terminating in different laminae, and by selectively targeting specific populations of excitatory and inhibitory neurons, these “interareal” pathways can differentially control the timing and strength of synaptic inputs onto individual neurons, resulting in layer-specific computations. Due to the rapid development in transgenic techniques, the mouse has emerged as a powerful mammalian model for understanding the rules by which cortical circuits organize and function. Here we review our understanding of how cortical lamination constrains long-range communication in the mammalian brain, with an emphasis on the mouse visual cortical network. We discuss the laminar architecture underlying interareal communication, the role of neocortical layers in organizing the balance of excitatory and inhibitory actions, and highlight the structure and function of layer 1 in mouse visual cortex.

Electro-Magnetic Flow Control to Enable Natural Laminar Flow Wings

Data.gov (United States)

National Aeronautics and Space Administration — This research team has developed a solid-state electromagnetic device that, when embedded along the leading edge of an aircraft wing, can disrupt laminar air flow on...

Evaluation of three ancillary treatments in the management of equine grass sickness.

Science.gov (United States)

Fintl, C; McGorum, B C

2002-09-28

Brotizolam, acetylcysteine and aloe vera gel were evaluated as ancillary treatments for 29 cases of equine grass sickness. None of the treatments had any significant beneficial effect on the survival of the horses. However, 11 of 13 horses with mild chronic grass sickness survived solely with intensive nursing care.

Response to acoustic forcing of laminar coflow jet diffusion flames

KAUST Repository

Chrystie, Robin; Chung, Suk-Ho

2014-01-01

Toward the goal of understanding and controlling instability in combustion systems, we present a fundamental characterization of the interaction of the buoyancy-induced instability in flickering flames with forced excitation of fuel supply. Laminar

Ancillary Services 4.0: A Top-To-Bottom Control-Based Approach for Solving Ancillary Services Problems in Smart Grids

DEFF Research Database (Denmark)

De Zotti, Giulia; Pourmousavi, S. Ali; Madsen, Henrik

2018-01-01

of AS are not able to benefit from the flexible energy resources. They also cannot cope with the new level of stochasticity, non-linearity, and dynamics of generation and flexibility. To overcome such issues and exploit the potential of flexibility resources, a new strategy is required. In this paper......Power systems are experiencing a large amount of renewable generation with highly stochastic and partly unpredictable characteristics. This change in energy production implies significant consequences related to the provision of ancillary services (AS). Current markets dedicated to the provision......, by capitalizing on flexibility resources' potential, AS 4.0 approach is proposed, which offers a comprehensive solution for the AS provision in the smart grid era....

Measurements of velocity-fields and temperature-fields in laminar and turbulent free convection boundary layers

International Nuclear Information System (INIS)

Fieg, G.

1975-02-01

This work deals with the hydrodynamics of laminar and turbulent free convection boundary layers on a vertical flat isothermal plate. Both for the laminar and turbulent region there is a good agreement with previous experimental and theoretical investigations. From these experiments one can draw important conclusions to the growth of instabilities in the transition region which lead to turbulence. (orig.) [de

Parametric Study on the Characteristics of Multiphase Laminar Flow with Density Difference in Various Microchannels

International Nuclear Information System (INIS)

Paek, Seung Ho; Kim, Dong Sung; Choi, Young Ki

2009-01-01

In this paper, we have performed a parametric study on the characteristics of multiphase laminar flow with density difference in various microchannels. The interface between multiphase fluids is rotated by the gravitational forces induced by density difference. The numerical simulations were carried out via commercial CFD package to study the characteristics of multiphase laminar flow. The results of the numerical simulations in this study were verified by comparing with the previously reported experimental results in the literature. We have also proposed a new dimensionless relationship between dimensionless rotation angle of interface and dimensionless parameters are proposed for square microchannels with various aspect ratios. The dimensionless relationship could be widely applied to the reliable design of various microfluidic devices dealing with multiphase laminar flow

Arc Voltage Fluctuation in DC Laminar and Turbulent Plasma Jets Generation

International Nuclear Information System (INIS)

Pan Wenxia; Meng Xian; Wu Chengkang

2006-01-01

Arc voltage fluctuations in a direct current (DC) non-transferred arc plasma generator are experimentally studied, in generating a jet in the laminar, transitional and turbulent regimes. The study is with a view toward elucidating the mechanism of the fluctuations and their relationship with the generating parameters, arc root movement and flow regimes. Results indicate that the existence of a 300 Hz alternating current (AC) component in the power supply ripples does not cause the transition of the laminar plasma jet into a turbulent state. There exists a high frequency fluctuation at 4 kHz in the turbulent jet regime. It may be related to the rapid movement of the anode attachment point of the arc

Management of Ovarian Cysts by Laparoscopic Extracorporeal Approach Using Single Ancillary Trocar

Directory of Open Access Journals (Sweden)

Metin Capar

2009-12-01

Conclusion: This technique does not require the use of two or more ancillary trocars or widening of the trocar incision. The duration of surgery can be shortened considerably and complete excision of the cystic capsule can be performed. Homeostasis was achieved using 3-0 polyglactin sutures. No electrocoagulation was required.

Ethics of Ancillary Care in Clinical Trials in Low Income Countries: A ...

African Journals Online (AJOL)

AJRH Managing Editor

income countries where HIV incidence is high, but the benefits of research are ... provision of ancillary care – medical care provided to clinical trial participants during a ... to or use of quality delivery services is an issue of ... with drastically reduced costs, questions arise over .... The 'partial entrustment' model differentiates.

The SPICE concept - An approach to providing geometric and other ancillary information needed for interpretation of data returned from space science instruments

Science.gov (United States)

Acton, Charles H., Jr.

1990-01-01

The Navigation Ancillary Information Facility (NAIF), acting under the direction of NASA's Office of Space Science and Applications, and with substantial participation of the planetary science community, is designing and implementing an ancillary data system - called SPICE - to assist scientists in planning and interpreting scientific observations taken from spaceborne instruments. The principal objective of the implemented SPICE system is that it will hold the essential geometric and related ancillary information needed to recover the full value of science instrument data, and that it will facilitate correlations of individual instrument datasets with data obtained from other instruments on the same or other spacecraft.

The impact of communication barriers on diagnostic confidence and ancillary testing in the emergency department.

Science.gov (United States)

Garra, Gregory; Albino, Hiram; Chapman, Heather; Singer, Adam J; Thode, Henry C

2010-06-01

Communication barriers (CBs) compromise the diagnostic power of the medical interview and may result in increased reliance on diagnostic tests or incorrect test ordering. The prevalence and degree to which these barriers affect diagnosis, testing, and treatment are unknown. To quantify and characterize CBs encountered in the Emergency Department (ED), and assess the effect of CBs on initial diagnosis and perceived reliance on ancillary testing. This was a prospective survey completed by emergency physicians after initial adult patient encounters. CB severity, diagnostic confidence, and reliance on ancillary testing were quantified on a 100-mm Visual Analog Scale (VAS) from least (0) to most (100). Data were collected on 417 ED patient encounters. CBs were reported in 46%; with a mean severity of 50 mm on a 100-mm VAS with endpoints of "perfect communication and "no communication." Language was the most commonly reported form of CB (28%). More than one CB was identified in 6%. The 100-mm VAS rating of diagnostic confidence was lower in patients with perceived CBs (64 mm) vs. those without CBs (80 mm), p Communication barriers in our ED setting were common, and resulted in lower diagnostic confidence and increased perception that ancillary tests are needed to narrow the diagnosis. Copyright 2010 Elsevier Inc. All rights reserved.

A combined PHREEQC-2/parallel fracture model for the simulation of laminar/non-laminar flow and contaminant transport with reactions

Science.gov (United States)

Masciopinto, Costantino; Volpe, Angela; Palmiotta, Domenico; Cherubini, Claudia

2010-09-01

A combination of a parallel fracture model with the PHREEQC-2 geochemical model was developed to simulate sequential flow and chemical transport with reactions in fractured media where both laminar and turbulent flows occur. The integration of non-laminar flow resistances in one model produced relevant effects on water flow velocities, thus improving model prediction capabilities on contaminant transport. The proposed conceptual model consists of 3D rock-blocks, separated by horizontal bedding plane fractures with variable apertures. Particle tracking solved the transport equations for conservative compounds and provided input for PHREEQC-2. For each cluster of contaminant pathways, PHREEQC-2 determined the concentration for mass-transfer, sorption/desorption, ion exchange, mineral dissolution/precipitation and biodegradation, under kinetically controlled reactive processes of equilibrated chemical species. Field tests have been performed for the code verification. As an example, the combined model has been applied to a contaminated fractured aquifer of southern Italy in order to simulate the phenol transport. The code correctly fitted the field available data and also predicted a possible rapid depletion of phenols as a result of an increased biodegradation rate induced by a simulated artificial injection of nitrates, upgradient to the sources.

A laminar flow unit for the care of critically ill newborn infants

Directory of Open Access Journals (Sweden)

Perez JM

2013-10-01

Full Text Available Jose MR Perez,1 Sergio G Golombek,2 Carlos Fajardo,3 Augusto Sola41Stella Maris Hospital, International Neurodevelopment Neonatal Center (CINN, Sao Paulo, Brazil; 2M Fareri Children’s Hospital, Westchester Medical Center, New York Medical College, Valhalla, NY, USA; 3University of Calgary, Calgary, Canada; 4St Jude Hospital, Fullerton, California, CA, USAIntroduction: Medical and nursing care of newborns is predicated on the delicate control and balance of several vital parameters. Closed incubators and open radiant warmers are the most widely used devices for the care of neonates in intensive care; however, several well-known limitations of these devises have not been resolved. The use of laminar flow is widely used in many fields of medicine, and may have applications in neonatal care.Objective: To describe the neonatal laminar flow unit, a new equipment we designed for care of ill newborns.Methods: The idea, design, and development of this device was completed in Sao Paulo, Brazil. The unit is an open mobile bed designed with the objective of maintaining the advantages of the incubator and radiant warmer, while overcoming some of their inherent shortcomings; these shortcomings include noise, magnetic fields and acrylic barriers in incubators, and lack of isolation and water loss through skin in radiant warmers. The unit has a pump that aspirates environmental air which is warmed by electrical resistance and decontaminated with High Efficiency Particulate Air Filter (HEPA filters (laminar flow. The flow is directed by an air flow directioner. The unit has an embedded humidifier to increase humidity in the infant’s microenvironment and a servo control mechanism for regulation of skin temperature.Results: The laminar flow unit is open and facilitates access of care providers and family, which is not the case in incubators. It provides warming by convection at an air velocity of 0.45 m/s, much faster than an incubator (0.1 m/s. The system

Modified laminar flow biological safety cabinet.

Science.gov (United States)

McGarrity, G J; Coriell, L L

1974-10-01

Tests are reported on a modified laminar flow biological safety cabinet in which the return air plenum that conducts air from the work area to the high efficiency particulate air filters is under negative pressure. Freon gas released inside the cabinet could not be detected outside by a freon gas detection method capable of detecting 10(-6) cc/s. When T3 bacteriophage was aerosolized 5 cm outside the front opening in 11 tests, no phage could be detected inside the cabinet with the motor-filter unit in operation. An average of 2.8 x 10(5) plaque-forming units (PFU)/ft(3) (ca. 0.028 m(3)) were detected with the motor-filter unit not in operation, a penetration of 0.0%. Aerosolization 5 cm inside the cabinet yielded an average of 10 PFU/ft(3) outside the cabinet with the motor-filter unit in operation and an average of 4.1 x 10(5) PFU/ft(3) with the motor-filter unit not in operation, a penetration of 0.002%. These values are the same order of effectiveness as the positive-pressure laminar flow biological safety cabinets previously tested. The advantages of the negative-pressure return plenum design include: (i) assurance that if cracks or leaks develop in the plenum it will not lead to discharge of contaminated air into the laboratory; and (ii) the price is lower due to reduced manufacturing costs.

Laminar burning velocities at elevated pressures for gasoline and gasoline surrogates associated with RON

KAUST Repository

Mannaa, Ossama

2015-06-01

The development and validation of a new gasoline surrogate using laminar flame speed as a target parameter is presented. Laminar burning velocities were measured using a constant-volume spherical vessel with ignition at the center of the vessel. Tested fuels included iso-octane, n-heptane, toluene, various mixtures of primary reference fuels (PRFs) and toluene reference fuels (TRFs) and three gasoline fuels of 70, 85 and 95 RON (FACE J, C and F) at the initial temperature of 358K and pressures up to 0.6MPa in the equivalence ratio ranging from 0.8 to 1.6. Normalized laminar burning velocity data were mapped into a tri-component mixture space at different experimental conditions to allocate different gasoline surrogates for different gasoline fuels, having RON of 70, 85 and 95. The surrogates of TRF-70-4 (17.94% iso-C8H18 +42.06% n-C7H16 +40% C7H8), TRF-85-1 (77.4% iso-C8H18 +17.6% n-C7H16 +5% C7H8), and TRF-95-1 (88.47% iso-C8H18 +6.53% n-C7H16 +5% C7H8) of RON 70, 85 and 95, respectively, are shown to successfully emulate the burning rate characteristics of the gasoline fuels associated with these RONs under the various experimental conditions investigated. An empirical correlation was derived to obtain laminar burning velocities at pressures that are experimentally unattainable as high as 3.0MPa. Laminar burning velocities were comparable to the simulated values for lean and stoichiometric flames but they were relatively higher than the simulated values for rich flames. A flame instability assessment was conducted by determining Markstein length, critical Pecklet number, and critical Karlovitz number at the onset of flame instability.

Analytical solution of laminar-laminar stratified two-phase flows with curved interfaces

International Nuclear Information System (INIS)

Brauner, N.; Rovinsky, J.; Maron, D.M.

1995-01-01

The present study represents a complete analytical solution for laminar two-phase flows with curved interfaces. The solution of the Navier-Stokes equations for the two-phases in bipolar coordinates provides the 'flow monograms' describe the relation between the interface curvature and the insitu flow geometry when given the phases flow rates and viscosity ratios. Energy considerations are employed to construct the 'interface monograms', whereby the characteristic interfacial curvature is determined in terms of the phases insitu holdup, pipe diameter, surface tension, fluids/wall adhesion and gravitation. The two monograms are then combined to construct the system 'operational monogram'. The 'operational monogram' enables the determination of the interface configuration, the local flow characteristics, such as velocity profiles, wall and interfacial shear stresses distribution as well as the integral characteristics of the two-phase flow: phases insitu holdup and pressure drop

Analytical solution of laminar-laminar stratified two-phase flows with curved interfaces

Energy Technology Data Exchange (ETDEWEB)

Brauner, N.; Rovinsky, J.; Maron, D.M. [Tel-Aviv Univ. (Israel)

1995-09-01

The present study represents a complete analytical solution for laminar two-phase flows with curved interfaces. The solution of the Navier-Stokes equations for the two-phases in bipolar coordinates provides the `flow monograms` describe the relation between the interface curvature and the insitu flow geometry when given the phases flow rates and viscosity ratios. Energy considerations are employed to construct the `interface monograms`, whereby the characteristic interfacial curvature is determined in terms of the phases insitu holdup, pipe diameter, surface tension, fluids/wall adhesion and gravitation. The two monograms are then combined to construct the system `operational monogram`. The `operational monogram` enables the determination of the interface configuration, the local flow characteristics, such as velocity profiles, wall and interfacial shear stresses distribution as well as the integral characteristics of the two-phase flow: phases insitu holdup and pressure drop.

An Experimental Measurement on Laminar Burning Velocities and Markstein Length of Iso-Butane-Air Mixtures at Ambient Conditions

Directory of Open Access Journals (Sweden)

Yousif Alaeldeen Altag

2016-01-01

Full Text Available In the present work, experimental investigation on laminar combustion of iso-butane-air mixtures was conducted in constant volume explosion vessel. The experiments were conducted at wide range of equivalence ratios ranging between Ф = 0.6 and 1.4 and atmospheric pressure of 0.1 MPa and ambient temperature of 303K. Using spherically expanding flame method, flame parameters including stretched, unstretched flame propagation speeds, laminar burning velocities and Markstein length were calculated. For laminar burning velocities the method of error bars of 95% confidence level was applied. In addition, values of Markstein lengths were measured in wide range of equivalence ratios to study the influence of stretch rate on flame instability and burning velocity. It was found that the stretched flame speed and laminar burning velocities increased with equivalence ratios and the peak value was obtained at equivalence ratio of Ф = 1.1. The Markstein length decreased with the increases in equivalence ratios, which indicates that the diffusion thermal flame instability increased at high equivalence ratios in richer mixture side. However, the total deviations in the laminar burning velocities have discrepancies of 1.2-2.9% for all investigated mixtures.

Mobile Bank Conditions for Laminar Micro-Rivers

OpenAIRE

Devauchelle, Olivier; Josserand, Christophe; Lagrée, Pierre-Yves; Zaleski, Stéphane

2008-01-01

International audience; The present study aims to establish a simple mechanistic model for river bank erosion. Recent experiments demonstrate that small-scale laminar flumes can develop erosion structures similar to those encountered in Nature. From Saint-Venant's Equations, a classical sediment transport law and a simple avalanche model, it is shown that bank failure caused by flow erosion can be represented through simple boundary conditions. These conditions are able to deal with the water...

Taylor dispersion in premixed combustion: Questions from turbulent combustion answered for laminar flames

Science.gov (United States)

Daou, Joel; Pearce, Philip; Al-Malki, Faisal

2018-02-01

We present a study of Taylor dispersion in premixed combustion and use it to clarify fundamental issues related to flame propagation in a flow field. In particular, simple analytical formulas are derived for variable density laminar flames with arbitrary Lewis number Le providing clear answers to important questions arising in turbulent combustion, when these questions are posed for the case of one-scale laminar parallel flows. Exploiting, in the context of a laminar Poiseuille flow model, a thick flame distinguished asymptotic limit for which the flow amplitude is large with the Reynolds number Re fixed, three main contributions are made. First, a link is established between Taylor dispersion [G. Taylor, Proc. R. Soc. London Ser. A 219, 186 (1953), 10.1098/rspa.1953.0139] and Damköhler's second hypothesis [G. Damköhler, Ber. Bunsen. Phys. Chem. 46, 601 (1940)] by describing analytically the enhancement of the effective propagation speed UT due to small flow scales. More precisely, it is shown that Damköhler's hypothesis is only partially correct for one-scale parallel laminar flows. Specifically, while the increase in UT due to the flow is shown to be directly associated with the increase in the effective diffusivity as suggested by Damköhler, our results imply that UT˜Re (for Re≫1 ) rather than UT˜√{Re} , as implied by Damköhler's hypothesis. Second, it is demonstrated analytically and confirmed numerically that, when UT is plotted versus the flow amplitude for fixed values of Re, the curve levels off to a constant value depending on Re. We may refer to this effect as the laminar bending effect as it mimics a similar bending effect known in turbulent combustion. Third, somewhat surprising implications associated with the dependence of UT and of the effective Lewis number Leeff on the flow are reported. For example, Leeff is found to vary from Le to Le-1 as Re varies from small to large values. Also, UT is found to be a monotonically increasing function

Experimental-theoretical analysis of laminar internal forced convection with nanofluids

Energy Technology Data Exchange (ETDEWEB)

Cerqueira, Ivana G.; Cotta, Renato M. [Lab. of Transmission and Technology of Heat-LTTC. Mechanical Eng. Dept. - POLI and COPPE/UFRJ, Rio de Janeiro, RJ (Brazil)], E-mail: cotta@mecanica.coppe.ufrj.br; Mota, Carlos Alberto A. [Conselho Nacional de Pesquisas - CNPq, Brasilia, DF (Brazil)], e-mail: carlosal@cnpq.br; Nunes, Jeziel S. [INPI, Rio de Janeiro, RJ (Brazil)], e-mail: jeziel@inpi.gov.br

2010-07-01

This work reports fundamental experimental-theoretical research related to heat transfer enhancement in laminar channel flow with nanofluids, which are essentially modifications of the base fluid with the dispersion of metal oxide nanoparticles. The theoretical work was performed by making use of mixed symbolic-numerical computation (Mathematica 7.0 platform) and a hybrid numerical-analytical methodology (Generalized Integral Transform Technique - GITT) in accurately handling the governing partial differential equations for the heat and fluid flow problem formulation with temperature dependency in all the thermophysical properties. Experimental work was also undertaken based on a thermohydraulic circuit built for this purpose, and sample results are presented to verify the proposed model. The aim is to illustrate detailed modeling and robust simulation attempting to reach an explanation of the controversial heat transfer enhancement observed in laminar forced convection with nanofluids. (author)

Resource and revenue potential of California residential load participation in ancillary services

International Nuclear Information System (INIS)

Mathieu, Johanna L.; Dyson, Mark E.H.; Callaway, Duncan S.

2015-01-01

Increasing penetrations of intermittent renewable energy resources will require additional power system services. California recently adopted an energy storage mandate to support its renewable portfolio standard, which requires 33% of delivered energy from renewables by 2020. The objective of this paper is to estimate the amount of energy storage that could be provided by residential thermostatically controlled loads, such as refrigerators and air conditioners, and the amount of revenue that could be earned by loads participating in ancillary services markets. We model load aggregations as virtual energy storage, and use simple dynamical system models and publicly available data to generate our resource and revenue estimates. We find that the resource potential is large: 10–40 GW/8–12 GWh, which is significantly more than that required by the mandate. We also find that regulation and spinning/non-spinning reserve revenues vary significantly depending upon type of load and, for heat pumps and air conditioners, climate zone. For example, mean regulation revenues for refrigerators are $11/year, for electric water heaters are $24/year, for air conditioners are $0-32/year, and for heat pumps are $22–56/year. Both consumer choices, such as appliance settings, and policy, such as the design of ancillary service compensation and appliance standards, could increase revenue potentials. - Highlights: • California's energy storage mandate requires 1.325 GW of energy storage by 2020. • Residential loads such as refrigerators have thermal energy storage. • California's residential loads could provide 10-40 GW/8-12 GWh of storage. • Loads participating in ancillary services markets could earn up to $56/load/year. • Consumer choices and policy mechanisms could increase revenue potentials

Use of laminar chromatographic methods for determination of separation conditions in column extraction chromatography

International Nuclear Information System (INIS)

Ghersini, G.; Cerrai, E.

1978-01-01

Possibilities of using laminar chromatographic methods (paper and thin-layer chromatography) to determine optimal separation conditions in column extraction chromatography are analysed. Most of the given laminar methods are presented as Rf-spectra, i.e. as dependences of Rf found experimentally on eluating solution component concentration. Interrelation between Rf and distribution coefficients of corresponding liquid extraction systems and retention volumes of chromatographic columns is considered. Literature data on extraction paper and thin-layer chromatography of elements with various immovable phases are presented

Simulation of laminar and turbulent concentric pipe flows with the isogeometric variational multiscale method

KAUST Repository

Ghaffari Motlagh, Yousef; Ahn, Hyungtaek; Hughes, Thomas Jr R; Calo, Victor M.

2013-01-01

We present an application of the residual-based variational multiscale modeling methodology to the computation of laminar and turbulent concentric annular pipe flows. Isogeometric analysis is utilized for higher-order approximation of the solution using Non-Uniform Rational B-Splines (NURBS). The ability of NURBS to exactly represent curved geometries makes NURBS-based isogeometric analysis attractive for the application to the flow through annular channels. We demonstrate the applicability of the methodology to both laminar and turbulent flow regimes. © 2012 Elsevier Ltd.

Water purification from cesium-137 and strontium-90 using natural and activated laminar and laminar-band silicates

International Nuclear Information System (INIS)

Kornilovich, B.Yu.; Pshinko, G.N.; Kosorukov, A.A.; Mas'ko, A.N.; Spasenova, L.N.; Dregval', T.N.

1991-01-01

Cesium-137 and strontium-90 radionuclides are studied for the process of their sorption from natural waters by basic representatives of disperse silicates: kaolinites of Glukhovetskoe and Glukhovskoe deposits (Ukraine), montmorillonites of the Cherkassy (Ukraine) and Oglanlin (Turkmenia) deposits, palygorskite and natural mixture of montmorillonite and palygorskite of the Cherkassy deposit. The best sorption properties are revealed for laminated silicates with a swelling structure (montmorillonites) and high-dispersive laminar-band silicates (palygorskite). It proved possible to improve sorption properties of silicate minerals for radionuclides by means of their mechanochemical activation

Soot Formation in Laminar Premixed Methane/Oxygen Flames at Atmospheric Pressure

Science.gov (United States)

Xu, F.; Lin, K.-C.; Faeth, G. M.

1998-01-01

Flame structure and soot formation were studied within soot-containing laminar premixed mc1hane/oxygen flames at atmospheric pressure. The following measurements were made: soot volume fractions by laser extinction, soot temperatures by multiline emission, gas temperatures (where soot was absent) by corrected fine-wire thermocouples, soot structure by thermophoretic sampling and transmission electron microscope (TEM), major gas species concentrations by sampling and gas chromatography, and gas velocities by laser velocimetry. Present measurements of gas species concentrations were in reasonably good agreement with earlier measurements due to Ramer et al. as well as predictions based on the detailed mechanisms of Frenklach and co-workers and Leung and Lindstedt: the predictions also suggest that H atom concentrations are in local thermodynamic equilibrium throughout the soot formation region. Using this information, it was found that measured soot surface growth rates could be correlated successfully by predictions based on the hydrogen-abstraction/carbon-addition (HACA) mechanisms of both Frenklach and co-workers and Colket and Hall, extending an earlier assessment of these mechanisms for premixed ethylene/air flames to conditions having larger H/C ratios and acetylene concentrations. Measured primary soot particle nucleation rates were somewhat lower than the earlier observations for laminar premixed ethylene/air flames and were significantly lower than corresponding rates in laminar diffusion flames. for reasons that still must be explained.

Laminar Boundary-Layer Instabilities on Hypersonic Cones: Computations for Benchmark Experiments

National Research Council Canada - National Science Library

Robarge, Tyler W; Schneider, Steven P

2005-01-01

.... The STABL code package and its PSE-Chem stability solver are used to compute first and second mode instabilities for both sharp and blunt cones at wind tunnel conditions, with laminar mean flows...

Laminar flow heat transfer studies in a twisted square duct for ...

Indian Academy of Sciences (India)

Department of Mechanical Engineering, Indian Institute of Technology,. Bombay 400 ... boundary conditions using commercially available software. ... Chang et al (1988) used numerical method to study laminar flow in a twisted elliptic tube for.

Measurements of laminar burning velocities and flame stability analysis for dissociated methanol-air-diluent mixtures at elevated temperatures and pressures

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xuan; Huang, Zuohua; Zhang, Zhiyuan; Zheng, Jianjun; Yu, Wu; Jiang, Deming [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

2009-06-15

The laminar burning velocities and Markstein lengths for the dissociated methanol-air-diluent mixtures were measured at different equivalence ratios, initial temperatures and pressures, diluents (N{sub 2} and CO{sub 2}) and dilution ratios by using the spherically outward expanding flame. The influences of these parameters on the laminar burning velocity and Markstein length were analyzed. The results show that the laminar burning velocity of dissociated methanol-air mixture increases with an increase in initial temperature and decreases with an increase in initial pressure. The peak laminar burning velocity occurs at equivalence ratio of 1.8. The Markstein length decreases with an increase in initial temperature and initial pressure. Cellular flame structures are presented at early flame propagation stage with the decrease of equivalence ratio or dilution ratio. The transition positions can be observed in the curve of flame propagation speed to stretch rate, indicating the occurrence of cellular structure at flame fronts. Mixture diluents (N{sub 2} and CO{sub 2}) will decrease the laminar burning velocities of mixtures and increase the sensitivity of flame front to flame stretch rate. Markstein length increases with an increase in dilution ratio except for very lean mixture (equivalence ratio less than 0.8). CO{sub 2} dilution has a greater impact on laminar flame speed and flame front stability compared to N{sub 2}. It is also demonstrated that the normalized unstretched laminar burning velocity is only related to dilution ratio and is not influenced by equivalence ratio. (author)

Accuracy of tracer stimulus response experiments in laminar flows

Czech Academy of Sciences Publication Activity Database

Chlup, Hynek; Novotný, Pavel; Žitný, R.

2012-01-01

Roč. 55, 23-24 (2012), s. 6458-6462 ISSN 0017-9310 Institutional research plan: CEZ:AV0Z20760514 Keywords : residence time distribution * tracer injection * laminar convective dominated flow Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 2.315, year: 2012 http://www.sciencedirect.com/science/article/pii/S001793101200470X

Investigations of Sooting Laminar Coflow Diffusion Flames at Elevated Pressures

KAUST Repository

Steinmetz, Scott

2016-01-01

diameters are successfully measured in nitrogen-diluted ethylene-air laminar coflow flames at pressures of 4, 8, 12, and 16 atm. An increase in particle size with pressure is found up to 12 atm, where particle sizes plateau. Particle size in the annulus

An Investigation of Parallel Post-Laminar Flow through Coarse Granular Porous Media with the Wilkins Equation

Directory of Open Access Journals (Sweden)

Ashes Banerjee

2018-02-01

Full Text Available Behaviour of flow resistance with velocity is still undefined for post-laminar flow through coarse granular media. This can cause considerable errors during flow measurements in situations like rock fill dams, water filters, pumping wells, oil and gas exploration, and so on. Keeping the non-deviating nature of Wilkins coefficients with the hydraulic radius of media in mind, the present study further explores their behaviour to independently varying media size and porosity, subjected to parallel post-laminar flow through granular media. Furthermore, an attempt is made to simulate the post-laminar flow conditions with the help of a Computational Fluid Dynamic (CFD Model in ANSYS FLUENT, since conducting large-scale experiments are often costly and time-consuming. The model output and the experimental results are found to be in good agreement. Percentage deviations between the experimental and numerical results are found to be in the considerable range. Furthermore, the simulation results are statistically validated with the experimental results using the standard ‘Z-test’. The output from the model advocates the importance and applicability of CFD modelling in understanding post-laminar flow through granular media.

Allocation of reactive power support, active loss balancing and demand interruption ancillary services in MicroGrids

Energy Technology Data Exchange (ETDEWEB)

Gomes, Mario Helder [Departamento de Engenharia Electrotecnica, Instituto Politecnico de Tomar, Quinta do Contador, Estrada da Serra, 2300 Tomar (Portugal); Saraiva, Joao Tome [INESC Porto and Faculdade de Engenharia da Universidade do Porto, Campus da FEUP, Rua Dr. Roberto Frias, 4200 - 465 Porto (Portugal)

2010-10-15

MicroGrids represent a new paradigm for the operation of distribution systems and there are several advantages as well as challenges regarding their development. One of the advantages is related with the participation of MicroGrid agents in electricity markets and in the provision of ancillary services. This paper describes two optimization models to allocate three ancillary services among MicroGrid agents - reactive power/voltage control, active loss balancing and demand interruption. These models assume that MicroGrid agents participate in the day-ahead market sending their bids to the MicroGrid Central Controller, MGCC, that acts as an interface with the Market Operator. Once the Market Operator returns the economic dispatch of the MicroGrid agents, the MGCC checks its technical feasibility (namely voltage magnitude and branch flow limits) and activates an adjustment market to change the initial schedule and to allocate these three ancillary services. One of the models has crisp nature considering that voltage and branch flow limits are rigid while the second one admits that voltage and branch flow limits are modeled in a soft way using Fuzzy Set concepts. Finally, the paper illustrates the application of these models with a Case Study using a 55 node MV/LV network. (author)

Formation of coherent structures in 3D laminar mixing flows

NARCIS (Netherlands)

Speetjens, M.F.M.; Clercx, H.J.H.

2009-01-01

Mixing under laminar flow conditions is key to a wide variety of industrial systems of size extending from microns to meters. Examples range from the traditional (and still very relevant) mixing of viscous fluids via compact processing equipment down to emerging micro-fluidics applications. Profound

EXPERIMENTAL AND MODELING STUDY OF PREMIXED LAMINAR FLAMES OF ETHANOL AND METHANE.

Science.gov (United States)

Tran, Luc-Sy; Glaude, Pierre-Alexandre; Fournet, René; Battin-Leclerc, Frédérique

2013-04-18

To better understand the chemistry of the combustion of ethanol, the structure of five low pressure laminar premixed flames has been investigated: a pure methane flame (φ=1), three pure ethanol flames (φ=0.7, 1.0, and 1.3), and an ethanol/methane mixture flames (φ=1). The flames have been stabilized on a burner at a pressure of 6.7 kPa using argon as dilutant, with a gas velocity at the burner of 64.3 cm/s at 333 K. The results consist of mole fraction profiles of 20 species measured as a function of the height above the burner by probe sampling followed by online gas chromatography analyses. A mechanism for the oxidation of ethanol was proposed. The reactions of ethanol and acetaldehyde were updated and include recent theoretical calculations while that of ethenol, dimethyl ether, acetone, and propanal were added in the mechanism. This mechanism was also tested against experimental results available in the literature for laminar burning velocities and laminar premixed flame where ethenol was detected. The main reaction pathways of consumption of ethanol are analyzed. The effect of the branching ratios of reaction C 2 H 5 OH+OH→Products+H 2 O is also discussed.

Experimental Study of Cavitation in Laminar Flow

OpenAIRE

Croci , Kilian; Ravelet , Florent; ROBINET , Jean-Christophe; Danlos , Amélie

2017-01-01

An experimental setup has been especially developed in order to observe cavitation in laminar flows. Experiments have been carried out with a silicon oil of viscosity υ = 100cSt passing through a Venturi-type geometry with 18°/8° convergent/divergent angles respectively. The range of Reynolds numbers at the inlet section is between 350 and 1000. Two dynamic regimes are identified. They are characterized by two critical Reynolds numbers, induced by major hydrodynamic changes in the flow, in ad...

Laminar flow assisted anisotropic bacteria absorption for chemotaxis delivery of bacteria-attached microparticle

Science.gov (United States)

Huh, Keon; Oh, Darong; Son, Seok Young; Yoo, Hyung Jung; Song, Byeonghwa; Cho, Dong-il Dan; Seo, Jong-Mo; Kim, Sung Jae

2016-12-01

The concepts of microrobots has been drawn significant attentions recently since its unprecedented applicability in nanotechnology and biomedical field. Bacteria attached microparticles presented in this work are one of pioneering microrobot technology for self-propulsion or producing kinetic energy from ambient for their motions. Microfluidic device, especially utilizing laminar flow characteristics, were employed for anisotropic attachment of Salmonella typhimurium flagellated chemotactic bacteria to 30 um × 30 um and 50 um × 50 um microparticles that made of biodegradable polymer. Any toxic chemicals or harmful treatments were excluded during the attachment process and it finished within 100 s for the anisotropic attachment. The attachments were directly confirmed by fluorescent intensity changes and SEM visualization. Chemotaxis motions were tracked using aspartate and the maximum velocity of the bacteria-attached microrobot was measured to be 5 um/s which is comparable to prior state of art technologies. This reusable and scalable method could play a key role in chemotaxis delivery of functional microparticles such as drug delivery system.

MR microscopy of articular cartilage at 1.5 T: orientation and site dependence of laminar structures

International Nuclear Information System (INIS)

Yoshioka, Hiroshi; Anno, Izumi; Echigo, Junko; Itai, Yuji; Haishi, Tomoyuki; Uematsu, Takaaki; Matsuda, Yoshimasa; Kose, Katsumi; Lang, Philipp

2002-01-01

Abstract Objective. To evaluate MR microscopic images of normal-appearing porcine hyaline cartilage (n=15) in vitro obtained with an MR microscope using an independent console system (MRMICS) at 1.5 T.Design and results. The MRMICS is a portable imaging system consisting of a radiofrequency system, gradient power supplies and a personal computer. The images from the MRMICS showed a laminar structure of porcine cartilage similar to the structure demonstrated with other MR imaging techniques. The laminar structures of the articular cartilage, were, however heterogeneous in respect of signal intensity and thickness, which varied according to the site resected. The MR laminar appearance was most comparable to the staining with Masson's trichrome for collagen.Conclusion. MRMICS is a useful add-on system for obtaining microscopic MR images of articular cartilage in vitro. (orig.)

Effect of Brinkman number and magnetic field on laminar convection ...

African Journals Online (AJOL)

The effect of Brinkman number and magnetic field on laminar convection in a vertical plate channel with uniform and asymmetric temperatures has been studied. The dimensionless form of momentum and energy balanced equations has been solved using one term perturbation series solution. The solution of the ...

Ancillary procedure for early diagnosis of brain damage in children

International Nuclear Information System (INIS)

Sumi, Masatoshi; Sha, Tenei; Ryo, Fukko; Kagawa, Kotaro.

1979-01-01

CT scan of the head was performed on 14 patients with cerebral palsy, 16 with central coordination disorders, and 16 controls, and findings showing cerebral atrophy and enlargement of the cerebral ventricle were obtained in cases both of cerebral palsy and of central coordination disorders. To objectify these findings, 10 items were selected and evaluated according to 4 grades (0 - 3) and were compared. As a result, it was concluded that CT scan is an excellent ancillary procedure for early diagnosis of brain damages. (Tsunoda, M.)

EX1605L3 Dive05 Ancillary Data Collection including reports, kmls, spreadsheets, and data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1605L3: CAPSTONE CNMI &...

EX1605L3 Dive02 Ancillary Data Collection including reports, kmls, spreadsheets, and data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1605L3: CAPSTONE CNMI &...

EX1605L3 Dive07 Ancillary Data Collection including reports, kmls, spreadsheets, and data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1605L3: CAPSTONE CNMI &...

EX1605L3 Dive19 Ancillary Data Collection including reports, kmls, spreadsheets, and data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1605L3: CAPSTONE CNMI &...

EX1605L3 Dive12 Ancillary Data Collection including reports, kmls, spreadsheets, and data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1605L3: CAPSTONE CNMI &...

EX1605L3 Dive01 Ancillary Data Collection including reports, kmls, spreadsheets, and data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1605L3: CAPSTONE CNMI &...

EX1605L3 Dive13 Ancillary Data Collection including reports, kmls, spreadsheets, and data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1605L3: CAPSTONE CNMI &...

EX1605L3 Dive20 Ancillary Data Collection including reports, kmls, spreadsheets, and data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1605L3: CAPSTONE CNMI &...

Tensile behavior of unnotched and notched tungsten--copper laminar composites

International Nuclear Information System (INIS)

Hoffman, C.A.

1976-06-01

Relations were studied between the tensile strengths of unnotched and of notched, and elastic moduli of unnotched laminar sheet or foil composites and the amounts of reinforcement. Tungsten was used as the reinforcement and copper as the matrix, and the tests were run at room temperature. Three thicknesses of tungsten (i.e., 0.00254, 0.0127, and 0.0254 cm (0.001, 0.005, and 0.010 in) were used, and the nominal volume fraction of tungsten was varied from about 0.05 to 0.95. It was found that the tensile strength of the unnotched specimens could be related to the amount of reinforcement, as could the elastic moduli, and that these values could be predicted by use of the rule of mixtures. The tensile strengths of the notched laminar composites could be predicted by use of the rule of mixtures using strengths for notched constituents, provided notch effects did not predominate. (Author)

Features of the laminar-turbulent transition in supersonic axisymmetric microjets

Science.gov (United States)

Maslov, A. A.; Aniskin, V. M.; Mironov, S. G.

2016-10-01

In this paper, a supersonic core length of microjets is studied in terms of laminar-turbulent transition in the microjet mixing layer. Previously, it was discovered that this transition has a determining influence on the supersonic core length. A possibility of simulation of microjet flows is estimated through the use of Reynolds number computed by the nozzle diameter and the nozzle exit gas parameters. These experimental data were obtained using Pitot tube when the jets escaping from the nozzle of 0.6 mm into the low-pressure space. This experiment made it possible to achieve a large jet pressure ratio when the Reynolds number values were low which specify the microjets' behavior. The supersonic core length, phase of the laminar-turbulent transition and flow characteristics in the space are obtained. Such an approach provides simulation of the characteristics of microjets and macrojets, and also explains preliminary proposition and some data obtained for microjets.

Laminar and turbulent nozzle-jet flows and their acoustic near-field

International Nuclear Information System (INIS)

Bühler, Stefan; Obrist, Dominik; Kleiser, Leonhard

2014-01-01

We investigate numerically the effects of nozzle-exit flow conditions on the jet-flow development and the near-field sound at a diameter-based Reynolds number of Re D = 18 100 and Mach number Ma = 0.9. Our computational setup features the inclusion of a cylindrical nozzle which allows to establish a physical nozzle-exit flow and therefore well-defined initial jet-flow conditions. Within the nozzle, the flow is modeled by a potential flow core and a laminar, transitional, or developing turbulent boundary layer. The goal is to document and to compare the effects of the different jet inflows on the jet flow development and the sound radiation. For laminar and transitional boundary layers, transition to turbulence in the jet shear layer is governed by the development of Kelvin-Helmholtz instabilities. With the turbulent nozzle boundary layer, the jet flow development is characterized by a rapid changeover to a turbulent free shear layer within about one nozzle diameter. Sound pressure levels are strongly enhanced for laminar and transitional exit conditions compared to the turbulent case. However, a frequency and frequency-wavenumber analysis of the near-field pressure indicates that the dominant sound radiation characteristics remain largely unaffected. By applying a recently developed scaling procedure, we obtain a close match of the scaled near-field sound spectra for all nozzle-exit turbulence levels and also a reasonable agreement with experimental far-field data

High-Fidelity Aerodynamic Shape Optimization for Natural Laminar Flow

Science.gov (United States)

Rashad, Ramy

To ensure the long-term sustainability of aviation, serious effort is underway to mitigate the escalating economic, environmental, and social concerns of the industry. Significant improvement to the energy efficiency of air transportation is required through the research and development of advanced and unconventional airframe and engine technologies. In the quest to reduce airframe drag, this thesis is concerned with the development and demonstration of an effective design tool for improving the aerodynamic efficiency of subsonic and transonic airfoils. The objective is to advance the state-of-the-art in high-fidelity aerodynamic shape optimization by incorporating and exploiting the phenomenon of laminar-turbulent transition in an efficient manner. A framework for the design and optimization of Natural Laminar Flow (NLF) airfoils is developed and demonstrated with transition prediction capable of accounting for the effects of Reynolds number, freestream turbulence intensity, Mach number, and pressure gradients. First, a two-dimensional Reynolds-averaged Navier-Stokes (RANS) flow solver has been extended to incorporate an iterative laminar-turbulent transition prediction methodology. The natural transition locations due to Tollmien-Schlichting instabilities are predicted using the simplified eN envelope method of Drela and Giles or, alternatively, the compressible form of the Arnal-Habiballah-Delcourt criterion. The boundary-layer properties are obtained directly from the Navier-Stokes flow solution, and the transition to turbulent flow is modeled using an intermittency function in conjunction with the Spalart-Allmaras turbulence model. The RANS solver is subsequently employed in a gradient-based sequential quadratic programming shape optimization framework. The laminar-turbulent transition criteria are tightly coupled into the objective and gradient evaluations. The gradients are obtained using a new augmented discrete-adjoint formulation for non-local transition

Laminar motion of the incompressible fluids in self-acting thrust bearings with spiral grooves.

Science.gov (United States)

Velescu, Cornel; Popa, Nicolae Calin

2014-01-01

We analyze the laminar motion of incompressible fluids in self-acting thrust bearings with spiral grooves with inner or external pumping. The purpose of the study is to find some mathematical relations useful to approach the theoretical functionality of these bearings having magnetic controllable fluids as incompressible fluids, in the presence of a controllable magnetic field. This theoretical study approaches the permanent motion regime. To validate the theoretical results, we compare them to some experimental results presented in previous papers. The laminar motion of incompressible fluids in bearings is described by the fundamental equations of fluid dynamics. We developed and particularized these equations by taking into consideration the geometrical and functional characteristics of these hydrodynamic bearings. Through the integration of the differential equation, we determined the pressure and speed distributions in bearings with length in the "pumping" direction. These pressure and speed distributions offer important information, both quantitative (concerning the bearing performances) and qualitative (evidence of the viscous-inertial effects, the fluid compressibility, etc.), for the laminar and permanent motion regime.

Laminar Motion of the Incompressible Fluids in Self-Acting Thrust Bearings with Spiral Grooves

Directory of Open Access Journals (Sweden)

Cornel Velescu

2014-01-01

Full Text Available We analyze the laminar motion of incompressible fluids in self-acting thrust bearings with spiral grooves with inner or external pumping. The purpose of the study is to find some mathematical relations useful to approach the theoretical functionality of these bearings having magnetic controllable fluids as incompressible fluids, in the presence of a controllable magnetic field. This theoretical study approaches the permanent motion regime. To validate the theoretical results, we compare them to some experimental results presented in previous papers. The laminar motion of incompressible fluids in bearings is described by the fundamental equations of fluid dynamics. We developed and particularized these equations by taking into consideration the geometrical and functional characteristics of these hydrodynamic bearings. Through the integration of the differential equation, we determined the pressure and speed distributions in bearings with length in the “pumping” direction. These pressure and speed distributions offer important information, both quantitative (concerning the bearing performances and qualitative (evidence of the viscous-inertial effects, the fluid compressibility, etc., for the laminar and permanent motion regime.

Biomimetic structures for fluid drag reduction in laminar and turbulent flows

International Nuclear Information System (INIS)

Jung, Yong Chae; Bhushan, Bharat

2010-01-01

Biomimetics allows one to mimic nature to develop materials and devices of commercial interest for engineers. Drag reduction in fluid flow is one of the examples found in nature. In this study, nano, micro, and hierarchical structures found in lotus plant surfaces, as well as shark skin replica and a rib patterned surface to simulate shark skin structure were fabricated. Drag reduction efficiency studies on the surfaces were systematically carried out using water flow. An experimental flow channel was used to measure the pressure drop in laminar and turbulent flows, and the trends were explained in terms of the measured and predicted values by using fluid dynamics models. The slip length for various surfaces in laminar flow was also investigated based on the measured pressure drop. For comparison, the pressure drop for various surfaces was also measured using air flow.

MR microscopy of articular cartilage at 1.5 T: orientation and site dependence of laminar structures

Energy Technology Data Exchange (ETDEWEB)

Yoshioka, Hiroshi; Anno, Izumi; Echigo, Junko; Itai, Yuji [Department of Radiology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575 (Japan); Haishi, Tomoyuki; Uematsu, Takaaki; Matsuda, Yoshimasa; Kose, Katsumi [Institute of Applied Physics, University of Tsukuba, Tsukuba (Japan); Lang, Philipp [Department of Radiology, Brigham and Women' s Hospital, Boston, Massachusetts (United States)

2002-09-01

Abstract Objective. To evaluate MR microscopic images of normal-appearing porcine hyaline cartilage (n=15) in vitro obtained with an MR microscope using an independent console system (MRMICS) at 1.5 T.Design and results. The MRMICS is a portable imaging system consisting of a radiofrequency system, gradient power supplies and a personal computer. The images from the MRMICS showed a laminar structure of porcine cartilage similar to the structure demonstrated with other MR imaging techniques. The laminar structures of the articular cartilage, were, however heterogeneous in respect of signal intensity and thickness, which varied according to the site resected. The MR laminar appearance was most comparable to the staining with Masson's trichrome for collagen.Conclusion. MRMICS is a useful add-on system for obtaining microscopic MR images of articular cartilage in vitro. (orig.)

Market and policy barriers for demand response providing ancillary services in U.S. markets

Energy Technology Data Exchange (ETDEWEB)

Cappers, Peter [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); MacDonald, Jason [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Goldman, Charles [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

2013-03-01

This study provides an examination of various market and policy barriers to demand response providing ancillary services in both ISO/RTO and non-ISO/RTO regions, especially at the program provider level. It is useful to classify barriers in order to create a holistic understanding and identify parties that could be responsible for their removal. This study develops a typology of barriers focusing on smaller customers that must rely on a program provider (i.e., electric investor owned utility or IOU, ARC) to create an aggregated DR resource in order to bring ancillary services to the balancing authority. The barriers were identified through examinations of regulatory structures, market environments, and product offerings; and discussions with industry stakeholders and regulators. In order to help illustrate the differences in barriers among various wholesale market designs and their constituent retail environments, four regions were chosen to use as case studies: Colorado, Texas, Wisconsin, and New Jersey.

Separation-induced boundary layer transition: Modeling with a non-linear eddy-viscosity model coupled with the laminar kinetic energy equation

International Nuclear Information System (INIS)

Vlahostergios, Z.; Yakinthos, K.; Goulas, A.

2009-01-01

We present an effort to model the separation-induced transition on a flat plate with a semi-circular leading edge, using a cubic non-linear eddy-viscosity model combined with the laminar kinetic energy. A non-linear model, compared to a linear one, has the advantage to resolve the anisotropic behavior of the Reynolds-stresses in the near-wall region and it provides a more accurate expression for the generation of turbulence in the transport equation of the turbulence kinetic energy. Although in its original formulation the model is not able to accurately predict the separation-induced transition, the inclusion of the laminar kinetic energy increases its accuracy. The adoption of the laminar kinetic energy by the non-linear model is presented in detail, together with some additional modifications required for the adaption of the laminar kinetic energy into the basic concepts of the non-linear eddy-viscosity model. The computational results using the proposed combined model are shown together with the ones obtained using an isotropic linear eddy-viscosity model, which adopts also the laminar kinetic energy concept and in comparison with the existing experimental data.

Experimental test on aluminium rod submitted to a laminar water flow

International Nuclear Information System (INIS)

Britto Aghina, L.O. de; Cruz, J.R.B.

1986-06-01

The result obtained from a experiment with an aluminium rod submitted to a laminar water flow is compared to the result predicted by empirical correlations used in the vibration analysis of the RPR reactor fuel rods. (L.C.J.A.)

A generalized relationship for swirl decay in laminar pipe flow

Indian Academy of Sciences (India)

Swirling flow is of great importance in heat and mass transfer enhancements and in flow measurements. In this study, laminar swirling flow in a straight pipe was considered. Steady three-dimensional axisymmetric Navier–Stokes equations were solved numerically using a control volume approach. The swirl number ...

A generalized relationship for swirl decay in laminar pipe flow

Indian Academy of Sciences (India)

MS received 24 July 2008; revised 28 January 2010; accepted 1 February 2010. Abstract. Swirling flow is of great importance in heat and mass transfer enhance- ments and in flow measurements. In this study, laminar swirling flow in a straight pipe was considered. Steady three-dimensional axisymmetric Navier–Stokes ...

Development of Advanced High Lift Leading Edge Technology for Laminar Flow Wings

Science.gov (United States)

Bright, Michelle M.; Korntheuer, Andrea; Komadina, Steve; Lin, John C.

2013-01-01

This paper describes the Advanced High Lift Leading Edge (AHLLE) task performed by Northrop Grumman Systems Corporation, Aerospace Systems (NGAS) for the NASA Subsonic Fixed Wing project in an effort to develop enabling high-lift technology for laminar flow wings. Based on a known laminar cruise airfoil that incorporated an NGAS-developed integrated slot design, this effort involved using Computational Fluid Dynamics (CFD) analysis and quality function deployment (QFD) analysis on several leading edge concepts, and subsequently down-selected to two blown leading-edge concepts for testing. A 7-foot-span AHLLE airfoil model was designed and fabricated at NGAS and then tested at the NGAS 7 x 10 Low Speed Wind Tunnel in Hawthorne, CA. The model configurations tested included: baseline, deflected trailing edge, blown deflected trailing edge, blown leading edge, morphed leading edge, and blown/morphed leading edge. A successful demonstration of high lift leading edge technology was achieved, and the target goals for improved lift were exceeded by 30% with a maximum section lift coefficient (Cl) of 5.2. Maximum incremental section lift coefficients ( Cl) of 3.5 and 3.1 were achieved for a blown drooped (morphed) leading edge concept and a non-drooped leading edge blowing concept, respectively. The most effective AHLLE design yielded an estimated 94% lift improvement over the conventional high lift Krueger flap configurations while providing laminar flow capability on the cruise configuration.

Problems of making the laminar construction of the nuclear reactor safety hausing

International Nuclear Information System (INIS)

Ablewicz, Z.

1980-01-01

General specifications and operating conditions of a safety housing are followed by a characteristics of constructional materials and a description of basic problems connected with making the laminar structure of this housing. (author)

Bifurcation in a buoyant horizontal laminar jet

Science.gov (United States)

Arakeri, Jaywant H.; Das, Debopam; Srinivasan, J.

2000-06-01

The trajectory of a laminar buoyant jet discharged horizontally has been studied. The experimental observations were based on the injection of pure water into a brine solution. Under certain conditions the jet has been found to undergo bifurcation. The bifurcation of the jet occurs in a limited domain of Grashof number and Reynolds number. The regions in which the bifurcation occurs has been mapped in the Reynolds number Grashof number plane. There are three regions where bifurcation does not occur. The various mechanisms that prevent bifurcation have been proposed.

Experimental study of laminar mixed convection in a rod bundle with mixing vane spacer grids

Energy Technology Data Exchange (ETDEWEB)

Mohanta, Lokanath, E-mail: lxm971@psu.edu [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Cheung, Fan-Bill [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Bajorek, Stephen M.; Tien, Kirk; Hoxie, Chris L. [Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001 (United States)

2017-02-15

Highlights: • Investigated the heat transfer during mixed laminar convection in a rod bundle with linearly varying heat flux. • The Nusselt number increases downstream of the inlet with increasing Richardson number. • Developed an enhancement factor to account for the effects of mixed convection over the forced laminar heat transfer. - Abstract: Heat transfer by mixed convection in a rod bundle occurs when convection is affected by both the buoyancy and inertial forces. Mixed convection can be assumed when the Richardson number (Ri = Gr/Re{sup 2}) is on the order of unity, indicating that both forced and natural convection are important contributors to heat transfer. In the present study, data obtained from the Rod Bundle Heat Transfer (RBHT) facility was used to determine the heat transfer coefficient in the mixed convection regime, which was found to be significantly larger than those expected assuming purely forced convection based on the inlet flow rate. The inlet Reynolds (Re) number for the tests ranged from 500 to 1300, while the Grashof (Gr) number varied from 1.5 × 10{sup 5} to 3.8 × 10{sup 6} yielding 0.25 < Ri < 4.3. Using results from RBHT test along with the correlation from the FLECHT-SEASET test program for laminar forced convection, a new correlation ​is proposed for mixed convection in a rod bundle. The new correlation accounts for the enhancement of heat transfer relative to laminar forced convection.

Breaking through the hydrogen cost barrier by using electrolysis loads to access ancillary services and demand response programs

International Nuclear Information System (INIS)

Wilson, D.; McGillivray, R.

2009-01-01

This presentation described the use of hydrogen electrolysis as a load resource for handling grid instability resulting from the increased penetration of intermittent renewable power. In particular, it focused on Hydrogenics, the leading global supplier of industrial scale electrolysis equipment and fuel cells. The presentation included an overview of the current incentive and market value of ancillary services provided by the company and demand responses in a number of grids around the world. There is a link between the amount of ancillary services required by the grid and the penetration level of renewable energy power such as wind and solar. The ability of hydrogen generation from electrolysis to satisfy all the requirements of ancillary services markets was also demonstrated. The economic analysis of hydrogen generation was discussed with particular reference to the cost of hydrogen fully loading all capital, energy and operating costs. The resulting reduction in the cost of hydrogen was compared to the existing markets for hydrogen, including use of hydrogen as a fuel for municipal bus fleets relative to the existing cost of fossil fuel fleets. Current industrial hydrogen merchant and bulk market prices were also compared

Autoignited laminar lifted flames of methane/hydrogen mixtures in heated coflow air

KAUST Repository

Choi, Byungchul; Chung, Suk-Ho

2012-01-01

Autoignited lifted flame behavior in laminar jets of methane/hydrogen mixture fuels has been investigated experimentally in heated coflow air. Three regimes of autoignited lifted flames were identified depending on initial temperature and hydrogen

Correlation of Water Frost Porosity in Laminar Flow over Flat Surfaces

Science.gov (United States)

Kandula, Max

2011-01-01

A dimensionless correlation has been proposed for water frost porosity expressing its dependence on frost surface temperature and Reynolds number for laminar forced flow over a flat surface. The correlation is presented in terms of a dimensionless frost surface temperature scaled with the cold plate temperature, and the freezing temperature. The flow Reynolds number is scaled with reference to the critical Reynolds number for laminar-turbulent transition. The proposed correlation agrees satisfactorily with the simultaneous measurements of frost density and frost surface temperature covering a range of plate temperature, ambient air velocity, humidity, and temperature. It is revealed that the frost porosity depends primarily on the frost surface and the plate temperatures and the flow Reynolds number, and is only weakly dependent on the relative humidity. The results also point out the general character of frost porosity displaying a decrease with an increase in flow Reynolds number.

Fabrication of free-standing replicas of fragile, laminar, chitinous biotemplates

Energy Technology Data Exchange (ETDEWEB)

Lakhtakia, Akhlesh; Motyka, Michael A [Materials Research Institute and Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802 (United States); MartIn-Palma, Raul J; Pantano, Carlo G [Materials Research Institute and Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States)], E-mail: akhlesh@psu.edu

2009-09-01

The conformal-evaporated-film-by-rotation technique, followed by the dissolution of chitin in an aqueous solution of orthophosphoric acid, can be used to fabricate free-standing replicas of fragile, laminar, chitinous biotemplates. This novel approach was demonstrated using butterfly wings as biotemplates and GeSeSb chalcogenide glass for replicas. (communication)

Fabrication of free-standing replicas of fragile, laminar, chitinous biotemplates

International Nuclear Information System (INIS)

Lakhtakia, Akhlesh; Motyka, Michael A; MartIn-Palma, Raul J; Pantano, Carlo G

2009-01-01

The conformal-evaporated-film-by-rotation technique, followed by the dissolution of chitin in an aqueous solution of orthophosphoric acid, can be used to fabricate free-standing replicas of fragile, laminar, chitinous biotemplates. This novel approach was demonstrated using butterfly wings as biotemplates and GeSeSb chalcogenide glass for replicas. (communication)

Short-Term Output Variations in Wind Farms--Implications for Ancillary Services in the United States: Preprint

Energy Technology Data Exchange (ETDEWEB)

Cadogan, J. [U.S. Department of Energy (US); Milligan, M. [National Renewable Energy Laboratory (US); Wan, Y. [National Renewable Energy Laboratory (US); Kirby, B. [Oak Ridge National Laboratory (US)

2001-09-21

With the advent of competition in the electric power marketplace, this paper reviews changes that affect wind and other renewable energy technologies, and discusses the role of federal and state policies in the recent wind installations in the United States. In particular, it reviews the implications of ancillary service requirements on a wind farm and presents initial operating results of monitoring one Midwest wind farm. Under federal energy policy, each generator must purchase, or otherwise provide for, ancillary services, such as dispatch, regulation, operation reserve, voltage regulation, and scheduling required to move power to load. As a renewable technology that depends on the forces of nature, short-term output variations are inherently greater for a wind farm than for a gas-fired combined cycle or a supercritical coal-fired unit.

Dispersion of swimming algae in laminar and turbulent channel flows: consequences for photobioreactors.

Science.gov (United States)

Croze, Ottavio A; Sardina, Gaetano; Ahmed, Mansoor; Bees, Martin A; Brandt, Luca

2013-04-06

Shear flow significantly affects the transport of swimming algae in suspension. For example, viscous and gravitational torques bias bottom-heavy cells to swim towards regions of downwelling fluid (gyrotaxis). It is necessary to understand how such biases affect algal dispersion in natural and industrial flows, especially in view of growing interest in algal photobioreactors. Motivated by this, we here study the dispersion of gyrotactic algae in laminar and turbulent channel flows using direct numerical simulation (DNS) and a previously published analytical swimming dispersion theory. Time-resolved dispersion measures are evaluated as functions of the Péclet and Reynolds numbers in upwelling and downwelling flows. For laminar flows, DNS results are compared with theory using competing descriptions of biased swimming cells in shear flow. Excellent agreement is found for predictions that employ generalized Taylor dispersion. The results highlight peculiarities of gyrotactic swimmer dispersion relative to passive tracers. In laminar downwelling flow the cell distribution drifts in excess of the mean flow, increasing in magnitude with Péclet number. The cell effective axial diffusivity increases and decreases with Péclet number (for tracers it merely increases). In turbulent flows, gyrotactic effects are weaker, but discernable and manifested as non-zero drift. These results should have a significant impact on photobioreactor design.

Laminar shear stress modulates endothelial luminal surface stiffness in a tissue-specific manner.

Science.gov (United States)

Merna, Nick; Wong, Andrew K; Barahona, Victor; Llanos, Pierre; Kunar, Balvir; Palikuqi, Brisa; Ginsberg, Michael; Rafii, Shahin; Rabbany, Sina Y

2018-04-17

Endothelial cells form vascular beds in all organs and are exposed to a range of mechanical forces that regulate cellular phenotype. We sought to determine the role of endothelial luminal surface stiffness in tissue-specific mechanotransduction of laminar shear stress in microvascular mouse cells and the role of arachidonic acid in mediating this response. Microvascular mouse endothelial cells were subjected to laminar shear stress at 4 dynes/cm 2 for 12 hours in parallel plate flow chambers that enabled real-time optical microscopy and atomic force microscopy measurements of cell stiffness. Lung endothelial cells aligned parallel to flow, while cardiac endothelial cells did not. This rapid alignment was accompanied by increased cell stiffness. The addition of arachidonic acid to cardiac endothelial cells increased alignment and stiffness in response to shear stress. Inhibition of arachidonic acid in lung endothelial cells and embryonic stem cell-derived endothelial cells prevented cellular alignment and decreased cell stiffness. Our findings suggest that increased endothelial luminal surface stiffness in microvascular cells may facilitate mechanotransduction and alignment in response to laminar shear stress. Furthermore, the arachidonic acid pathway may mediate this tissue-specific process. An improved understanding of this response will aid in the treatment of organ-specific vascular disease. © 2018 John Wiley & Sons Ltd.

Predictions of laminar natural convection in heated cavities

International Nuclear Information System (INIS)

Winters, K.H.

1982-06-01

Several examples of laminar, natural convection in heated cavities are discussed with illustrative calculations. These include convection in a square cavity at high Rayleigh number; in a narrow cavity at moderate aspect ratio; in a rectangular cavity heated from below; in a trapezoidal cavity, and in a rectangular cavity containing a conducting obstruction. The steady equations for the velocity, pressure and temperature are solved in the Boussinesq approximation, using a standard Galerkin formulation of the finite-element method. (author)

Cold laminar galvanizing: a new anti-corrosion concept

International Nuclear Information System (INIS)

Bagnulo, L.H.

1984-01-01

Cold laminar galvanizing, a recent anticorrosion technology, now combines the most positive characteristics of the hot galvanizing protective systems. This patented technology has a zinc laminated foil (obtained by processing 99.9% pure zinc ingots) that is homogeneous and isotropic, with a standard thickness of 80-100μm. This foil is backed with an electro-conductive, selfadhesive glue prepared under an original formula. The zinc laminated foil offers excellent anchorage and elevated resistance to the main atmospheric agents

Nanocomposites transparentes multifuncionales de hidróxido doble laminares

OpenAIRE

Fernández Vilaber, Antonio

2017-01-01

Este trabajo trata sobre obtener una serie de materiales nanocompuestos en forma de película para usarlos como plásticos de invernadero. Para ello se sintetizarán hidróxidos dobles laminares modificados con un agente blanqueante óptico que mejorará las propiedades ópticas del material Escuela Técnica Superior de Ingeniería Industrial Universidad Politécnica de Cartagena

Temperature decline thermography for laminar-turbulent transition detection in aerodynamics

Science.gov (United States)

von Hoesslin, Stefan; Stadlbauer, Martin; Gruendmayer, Juergen; Kähler, Christian J.

2017-09-01

Detailed knowledge about laminar-turbulent transition and heat transfer distribution of flows around complex aerodynamic components are crucial to achieve highest efficiencies in modern aerodynamical systems. Several measurement techniques have been developed to determine those parameters either quantitatively or qualitatively. Most of them require extensive instrumentation or give unreliable results as the boundary conditions are often not known with the required precision. This work introduces the simple and robust temperature decline method to qualitatively detect the laminar-turbulent transition and the respective heat transfer coefficients on a surface exposed to an air flow, according to patent application Stadlbauer et al. (Patentnr. WO2014198251 A1, 2014). This method provides results which are less sensitive to control parameters such as the heat conduction into the blade material and temperature inhomogeneities in the flow or blade. This method was applied to measurements with NACA0018 airfoils exposed to the flow of a calibration-free jet at various Reynolds numbers and angles of attack. For data analysis, a post-processing method was developed and qualified to determine a quantity proportional to the heat transfer coefficient into the flow. By plotting this quantity for each pixel of the surface, a qualitative, two-dimensional heat transfer map was obtained. The results clearly depicted the areas of onset and end of transition over the full span of the model and agreed with the expected behavior based on the respective flow condition. To validate the approach, surface hotfilm measurements were conducted simultaneously on the same NACA profile. Both techniques showed excellent agreement. The temperature decline method allows to visualize laminar-turbulent transitions on static or moving parts and can be applied on a very broad range of scales—from tiny airfoils up to large airplane wings.

Electrostatic quadrupole focused particle accelerating assembly with laminar flow beam

International Nuclear Information System (INIS)

Maschke, A. W.

1985-01-01

A charged particle accelerating assembly provided with a predetermined ratio of parametric structural characteristics and with related operating voltages applied to each of its linearly spaced focusing and accelerating quadrupoles, thereby to maintain a particle beam traversing the electrostatic fields of the quadrupoles in the assembly in an essentially laminar flow throughout the assembly

Uncertainty quantification-based robust aerodynamic optimization of laminar flow nacelle

Science.gov (United States)

Xiong, Neng; Tao, Yang; Liu, Zhiyong; Lin, Jun

2018-05-01

The aerodynamic performance of laminar flow nacelle is highly sensitive to uncertain working conditions, especially the surface roughness. An efficient robust aerodynamic optimization method on the basis of non-deterministic computational fluid dynamic (CFD) simulation and Efficient Global Optimization (EGO)algorithm was employed. A non-intrusive polynomial chaos method is used in conjunction with an existing well-verified CFD module to quantify the uncertainty propagation in the flow field. This paper investigates the roughness modeling behavior with the γ-Ret shear stress transport model including modeling flow transition and surface roughness effects. The roughness effects are modeled to simulate sand grain roughness. A Class-Shape Transformation-based parametrical description of the nacelle contour as part of an automatic design evaluation process is presented. A Design-of-Experiments (DoE) was performed and surrogate model by Kriging method was built. The new design nacelle process demonstrates that significant improvements of both mean and variance of the efficiency are achieved and the proposed method can be applied to laminar flow nacelle design successfully.

Fabrication of MgAl2O4 spinel/niobium laminar composites by plasma spraying

International Nuclear Information System (INIS)

Boncoeur, M.; Lochet, N.; Miomandre, F.; Schnedecker, G.

1994-01-01

The feasibility of plasma spray manufacturing of laminar ceramic matrix composites made of alternate thin layers of a ceramic oxide and a metal is demonstrated with a composite made of 7 layers, each 0.2 mm thick, of MgAl 2 O 4 spinel and niobium. Microstructure and mechanical characteristics have been studied with both as-sprayed and heat-treated under vacuum at 1400 C conditions. It is shown that the as-sprayed composite is brittle but becomes pseudo-plastic after heat treatment. These laminar composites are very attractive for the manufacturing of large surface, few millimeter thick components. (from authors). 4 figs., 4 refs

Convective heat transfer from rough surfaces with two-dimensional ribs - transitional and laminar flow

International Nuclear Information System (INIS)

Dalle Donne, M.; Meyer, L.

1978-01-01

Measurements of friction factor and heat transfer coefficients for two rods of 18.9 mm 0.D. with two-dimensional roughness, each in two different outer smooth tubes have been performed in turbulent and laminar flow. The turbulent flow results indicate that the flow was not thermally fully established, the isothermal data however agree reasonably well with our previously obtained general correlation. Laminar flow results can be correlated best when the Reynolds and Greatz numbers are evaluated at the temperature average between the temperature of the inner rod surface and of the outer smooth surface of the annulus, the average being weighted over the two surfaces. (orig.) [de

EX1504L2 Dive09 Ancillary Data Collection including reports, kmls, spreadsheets, images and data

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National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1504L2: Campaign to Address...

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National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1504L4: Campaign to Address...

EX1504L4 Dive01 Ancillary Data Collection including reports, kmls, spreadsheets, images and data

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National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1504L4: Campaign to Address...

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National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1504L2: Campaign to Address...

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National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1504L4: Campaign to Address...

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National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1504L2: Campaign to Address...

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National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1504L4: Campaign to Address...

EX1504L2 Dive10 Ancillary Data Collection including reports, kmls, spreadsheets, images and data

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National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1504L2: Campaign to Address...

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National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1504L4: Campaign to Address...

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National Oceanic and Atmospheric Administration, Department of Commerce — Standard suite of ancillary data files generated through a scripting process following an ROV dive on NOAA Ship Okeanos Explorer during EX1504L3: CAPSTONE Leg III:...

Unsteady Characteristics of Laminar Separation Bubbles; An Experimental and Numerical Investigation

NARCIS (Netherlands)

Baragona, M.

2004-01-01

Laminar separation bubbles may occur in a wide range of engineering applications such as turbomachinery flows, wind turbines, hydrofoils etc. Much attention has been given to their effect on the flow over airfoils because of the importance for an accurate prediction of lift, drag and heat transfer.

Histopathological diagnostic discrepancies in soft tissue tumours referred to a specialist centre: reassessment in the era of ancillary molecular diagnosis.

Science.gov (United States)

Thway, Khin; Wang, Jayson; Mubako, Taka; Fisher, Cyril

2014-01-01

Introduction. Soft tissue tumour pathology is a highly specialised area of surgical pathology, but soft tissue neoplasms can occur at virtually all sites and are therefore encountered by a wide population of surgical pathologists. Potential sarcomas require referral to specialist centres for review by pathologists who see a large number of soft tissue lesions and where appropriate ancillary investigations can be performed. We have previously assessed the types of diagnostic discrepancies between referring and final diagnosis for soft tissue lesions referred to our tertiary centre. We now reaudit this 6 years later, assessing changes in discrepancy patterns, particularly in relation to the now widespread use of ancillary molecular diagnostic techniques which were not prevalent in our original study. Materials and Methods. We compared the sarcoma unit's histopathology reports with referring reports on 348 specimens from 286 patients with suspected or proven soft tissue tumours in a one-year period. Results. Diagnostic agreement was seen in 250 cases (71.8%), with 57 (16.4%) major and 41 (11.8%) minor discrepancies. There were 23 cases of benign/malignant discrepancies (23.5% of all discrepancies). 50 ancillary molecular tests were performed, 33 for aiding diagnosis and 17 mutational analyses for gastrointestinal stromal tumour to guide therapy. Findings from ancillary techniques contributed to 3 major and 4 minor discrepancies. While the results were broadly similar to those of the previous study, there was an increase in frequency of major discrepancies. Conclusion. Six years following our previous study and notably now in an era of widespread ancillary molecular diagnosis, the overall discrepancy rate between referral and tertiary centre diagnosis remains similar, but there is an increase in frequency of major discrepancies likely to alter patient management. A possible reason for the increase in major discrepancies is the increasing lack of exposure to soft tissue

Laminar/transition sweeping flow-mixing model for wire-wrapped LMFBR assemblies

International Nuclear Information System (INIS)

Burns, K.F.; Rohsenow, W.M.; Todreas, N.E.

1980-07-01

Recent interest in analyzing the thermal hydraulic characteristics of LMFBR assemblies operating in the mixed convection regime motivates the extension of the aforementioned turbulent sweeping flow model to low Reynolds number flows. The accuracy to which knowledge of the mixing parameters is required has not been well determined, due to the increased influence of conduction and buoyancy effects with respect to energy transport at low Reynolds numbers. This study represents a best estimate attempt to correlate the existing low Reynolds number sweeping flow data. The laminar/transition model which is presented is expected to be useful in anayzing mixed convection conditions. However, the justification for making additional improvemements is contingent upon two factors. First, the ability of the proposed laminar/transition model to predict additional low Reynolds number sweeping flow data for other geometries needs to be investigated. Secondly, the sensitivity of temperature predictions to uncertainties in the values of the sweeping flow parameters should be quantified

Prevalence of influenza vaccination among nurses and ancillary workers in Italy: systematic review and meta analysis.

Science.gov (United States)

La Torre, Giuseppe; Mannocci, Alice; Ursillo, Paolo; Bontempi, Claudio; Firenze, Alberto; Panico, Maria Grazia; Sferrazza, Antonella; Ronga, Chiara; D'Anna, Adele; Amodio, Emanuele; Romano, Nino; Boccia, Antonio

2011-07-01

Italian Ministry of Health, recommends vaccination for seasonal influenza to all healthcare workers (HCW), particularly to nurses who have an important interaction with patients. The aim of this study is to conduct a systematic review in order to estimate the pooled prevalence of influenza vaccinations among nurses and ancillary workers in Italy and analyse the enhancing and hindering factors. The review was performed using 15 articles, six containing the prevalence of vaccination for nurses and ancillary workers, while the others qualitative analysis. In all the selected articles the score calculation has been carried out by using a protocol for observational studies. The nurses and ancillary workers pooled proportion of influenza vaccination was respectively 13.47% (95%CI 9.58-17.90%) and 12.52% (95%CI 9.97-15.31%). The Italian mean of influenza vaccination prevalence appear low if compared to other European countries, ranging from 15% to 29% in Countries such as UK, Germany, France. This situation of weakness should be seen as an opportunity to improve the vaccination rate for seasonal influenza significantly This should be done by intervening on the category which affirms caring less. In fact, this category has a priority to receive vaccination, due to their numbers and closer contact to patients. Research was conducted using medical database Scopus, PubMed, the search engine Google Scholar and ISI web of knowledge, and was concluded February 1st 2011.

Removal Action Work Plan for 105-DR and 105-F Building Interim Safe Storage Projects and Ancillary Buildings

International Nuclear Information System (INIS)

Morton, M.R.

2000-01-01

This document contains the removal action work plan for the 105-DR and 105-F Reactor buildings and ancillary facilities. These buildings and facilities are located in the 100-D/DR and 100-F Areas of the Hanford Site, which is owned and operated by the US Department of Energy (DOE), in Benton County, Washington. The 100 Areas (including the 100-D/DR and 100-F Areas) of the Hanford Site were placed on the US Environmental Protection Agency's (EPA's) National Priorities List under the ''Comprehensive Environmental Response, Compensation, and Liability Act of 1980'' (CERCLA). The DOE has determined that hazardous substances in the 105-DR and 105-F Reactor buildings and four ancillary facilities present a potential threat to human health or the environment. The DOE has also determined that a non-time critical removal action is warranted at these facilities. Alternatives for conducting a non-time critical removal action were evaluated in the ''Engineering Evaluation/Cost Analysis for the 105-DR and 105-F Reactor Facilities and Ancillary Facilities'' (DOE-RL 1998a). The engineering evaluation/cost analysis (EE/CA) resulted in the recommendation to decontaminate and demolish the contaminated reactor buildings (except for the reactor blocks) and the ancillary facilities and to construct a safe storage enclosure (SSE) over the reactor blocks. The recommendation was approved in an action memorandum (Ecology et al. 1998) signed by the Washington State Department of Ecology (Ecology), EPA, and DOE. The DOE is the agency responsible for implementing the removal actions in the 105-D/DR and 105-F Areas. Ecology is the lead regulatory agency for facilities in the 100-D/DR Area, and EPA is the lead regulatory agency for facilities in the 100-F Area. The term ''lead regulator agency'' hereinafter, refers to these authorities. This removal action work plan supports implementation of the non-time critical removal action

Impact of prenatal care provider on the use of ancillary health services during pregnancy

Science.gov (United States)

2013-01-01

Background Recent declines in the provision of prenatal care by family physicians and the integration of midwives into the Canadian health care system have led to a shift in the pattern of prenatal care provision; however it is unknown if this also impacts use of other health services during pregnancy. This study aimed to assess the impact of the type of prenatal care provider on the self-reported use of ancillary services during pregnancy. Methods Data for this study was obtained from the All Our Babies study, a community-based prospective cohort study of women’s experiences during pregnancy and the post-partum period. Chi-square tests and logistic regression were used to assess the association between type of prenatal care provider and use of ancillary health services in pregnancy. Results During pregnancy, 85.8% of women reported accessing ancillary health services. Compared to women who received prenatal care from a family physician, women who saw a midwife were less likely to call a nurse telephone advice line (OR = 0.30, 95% CI: 0.18-0.50) and visit the emergency department (OR = 0.47, 95% CI: 0.24-0.89), but were more likely receive chiropractic care (OR = 4.07, 95% CI: 2.49-6.67). Women who received their prenatal care from an obstetrician were more likely to visit a walk-in clinic (OR = 1.51, 95% CI: 1.11-2.05) than those who were cared for by a family physician. Conclusions Prenatal care is a complex entity and referral pathways between care providers and services are not always clear. This can lead to the provision of fragmented care and create opportunities for errors and loss of information. All types of care providers have a role in addressing the full range of health needs that pregnant women experience. PMID:23497179

Market and Policy Barriers for Demand Response Providing Ancillary Services in U.S. Markets

Energy Technology Data Exchange (ETDEWEB)

Cappers, Peter [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); MacDonald, Jason [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Goldman, Charles [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2013-03-01

In this study, we attempt to provide a comprehensive examination of various market and policy barriers to demand response providing ancillary services in both ISO/RTO and non-ISO/RTO regions, especially at the program provider level. It is useful to classify barriers in order to create a holistic understanding and identify parties that could be responsible for their removal. This study develops a typology of barriers focusing on smaller customers that must rely on a program provider (i.e., electric investor owned utility or IOU, ARC) to create an aggregated DR resource in order to bring ancillary services to the balancing authority.ii The barriers were identified through examinations of regulatory structures, market environments, and product offerings; and discussions with industry stakeholders and regulators. In order to help illustrate the differences in barriers among various wholesale market designs and their constituent retail environments, four regions were chosen to use as case studies: Colorado, Texas, Wisconsin, and New Jersey. We highlight the experience in each area as it relates to the identified barriers.

New alternatives for reference evapotranspiration estimation in West Africa using limited weather data and ancillary data supply strategies.

Science.gov (United States)

Landeras, Gorka; Bekoe, Emmanuel; Ampofo, Joseph; Logah, Frederick; Diop, Mbaye; Cisse, Madiama; Shiri, Jalal

2018-05-01

Accurate estimation of reference evapotranspiration ( ET 0 ) is essential for the computation of crop water requirements, irrigation scheduling, and water resources management. In this context, having a battery of alternative local calibrated ET 0 estimation methods is of great interest for any irrigation advisory service. The development of irrigation advisory services will be a major breakthrough for West African agriculture. In the case of many West African countries, the high number of meteorological inputs required by the Penman-Monteith equation has been indicated as constraining. The present paper investigates for the first time in Ghana, the estimation ability of artificial intelligence-based models (Artificial Neural Networks (ANNs) and Gene Expression Programing (GEPs)), and ancillary/external approaches for modeling reference evapotranspiration ( ET 0 ) using limited weather data. According to the results of this study, GEPs have emerged as a very interesting alternative for ET 0 estimation at all the locations of Ghana which have been evaluated in this study under different scenarios of meteorological data availability. The adoption of ancillary/external approaches has been also successful, moreover in the southern locations. The interesting results obtained in this study using GEPs and some ancillary approaches could be a reference for future studies about ET 0 estimation in West Africa.

Flow instability in laminar jet flames driven by alternating current electric fields

KAUST Repository

Kim, Gyeong Taek; Park, Daegeun; Cha, Min; Park, Jeong; Chung, Suk-Ho

2016-01-01

The effect of electric fields on the instability of laminar nonpremixed jet flames was investigated experimentally by applying the alternating current (AC) to a jet nozzle. We aimed to elucidate the origin of the occurrence of twin-lifted jet flames

Scanning PIV investigation of the laminar separation bubble on a SD7003 airfoil

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wei [Technische Universitaet Braunschweig, Institut fuer Stroemungsmechanik, Braunschweig (Germany); Iowa State University, Department of Aerospace Engineering, Ames, IA (United States); Hain, Rainer [Technische Universitaet Braunschweig, Institut fuer Stroemungsmechanik, Braunschweig (Germany); Institut fuer Aerodynamik und Stroemungstechnik, Deutsches Zentrum fuer Luft- und Raumfahrt e.V. (DLR), Braunschweig (Germany); Kaehler, Christian J. [Technische Universitaet Braunschweig, Institut fuer Stroemungsmechanik, Braunschweig (Germany); Universitaet der Bundeswehr Muenchen, Institut fuer Stroemungsmechanik und Aerodynamik, Neubiberg (Germany)

2008-10-15

A laminar separation bubble occurs on the suction side of the SD7003 airfoil at an angle of attack {alpha}=4-8 and a low Reynolds number less than 100,000, which brings about a significant adverse aerodynamic effect. The spatial and temporal structure of the laminar separation bubble was studied using the scanning PIV method at {alpha}=4 and Re=60,000 and 20,000. Of particular interest are the dynamic vortex behavior in transition process and the subsequent vortex evolution in the turbulent boundary layer. The flow was continuously sampled in a stack of parallel illuminated planes from two orthogonal views with a frequency of hundreds Hz, and PIV cross-correlation was performed to obtain the 2D velocity field in each plane. Results of both the single-sliced and the volumetric presentations of the laminar separation bubble reveal vortex shedding in transition near the reattachment region at Re=60,000. In a relatively long distance vortices characterized by paired wall-normal vorticity packets retain their identities in the reattached turbulent boundary layer, though vortices interact through tearing, stretching and tilting. Compared with the restricted LSB at Re=60,000, the flow at Re=20,000 presents an earlier separation and a significantly increased reversed flow region followed by ''huge'' vortical structures. (orig.)

Pricing Energy and Ancillary Services in a Day-Ahead Market for a Price-Taker Hydro Generating Company Using a Risk-Constrained Approach

Directory of Open Access Journals (Sweden)

Perica Ilak

2014-04-01

Full Text Available This paper analyzes a price-taker hydro generating company which participates simultaneously in day-ahead energy and ancillary services markets. An approach for deriving marginal cost curves for energy and ancillary services is proposed, taking into consideration price uncertainty and opportunity cost of water, which can later be used to determine hourly bid curves. The proposed approach combines an hourly conditional value-at-risk, probability of occurrence of automatic generation control states and an opportunity cost of water to determine energy and ancillary services marginal cost curves. The proposed approach is in a linear constraint form and is easy to implement in optimization problems. A stochastic model of the hydro-economic river basin is presented, based on the actual Vinodol hydropower system in Croatia, with a complex three-dimensional relationship between the power produced, the discharged water, and the head of associated reservoir.

Cortical laminar necrosis in dengue encephalitis-a case report.

Science.gov (United States)

Garg, Ravindra Kumar; Rizvi, Imran; Ingole, Rajan; Jain, Amita; Malhotra, Hardeep Singh; Kumar, Neeraj; Batra, Dhruv

2017-04-20

Dengue encephalitis is a rare neurological manifestation of dengue fever. Its clinical presentation is similar to other viral encephalitides and encephalopathy. No single specific finding on magnetic resonance imaging of dengue encephalitis has yet been documented. They are highly variable and atypical. A 15-year boy presented with fever, the headache and altered sensorium of 12-day duration. On neurological examination, his Glasgow Coma Scale score was 10 (E3M4V3). There was no focal neurological deficit. Laboratory evaluation revealed leukopenia and marked thrombocytopenia. Dengue virus IgM antibody was positive both in serum and cerebrospinal fluid. Magnetic resonance imaging of the brain revealed signal changes in bilateral parietooccipital and left frontal regions (left hemisphere more involved than the right hemisphere). There was gyriform enhancement bilateral parietooccipital regions consistent with cortical laminar necrosis. Bilaterally diffuse subcortical white matter was also involved and subtle T2 hyperintensity involving both basal ganglia was noted. Gradient echo sequence revealed presence of hemorrhage in the subcortical white matter. Patient was treated conservatively and received platelet transfusion. Patient became fully conscious after 7 days. In a patient with highly suggestive dengue e\\ephalitis, we describe an unusual magnetic resonance imaging finding. This report is possibly the first instance of cortical laminar necrosis in such a setting.

47 CFR 25.149 - Application requirements for ancillary terrestrial components in the mobile-satellite service...

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Application requirements for ancillary terrestrial components in the mobile-satellite service networks operating in the 1.5./1.6 GHz, 1.6/2.4 GHz and 2 GHz mobile-satellite service. 25.149 Section 25.149 Telecommunication FEDERAL COMMUNICATIONS...

Abnormal fetal cerebral laminar organization in cobblestone complex as seen on post-mortem MRI and DTI

International Nuclear Information System (INIS)

Widjaja, Elysa; Geibprasert, Sasikhan; Blaser, Susan; Rayner, Tammy; Shannon, Patrick

2009-01-01

We report a unique case of cobblestone complex using post-mortem MR and diffusion tensor imaging to assess the laminar organization of the fetal cerebrum. The imaging findings were correlated with autopsy findings. Abnormal cortical development in cobblestone complex resulted in disruption of normal laminar organization of the fetal brain, which was seen as interruption and nodularity of the high-signal T1 cortical band with increased anisotropy and medium diffusivity extending beyond the cortical band into the cerebral mantle on post-mortem MR and diffusion tensor imaging. (orig.)

Abnormal fetal cerebral laminar organization in cobblestone complex as seen on post-mortem MRI and DTI

Energy Technology Data Exchange (ETDEWEB)

Widjaja, Elysa; Geibprasert, Sasikhan; Blaser, Susan; Rayner, Tammy [Hospital for Sick Children, Department of Diagnostic Imaging, Toronto (Canada); Shannon, Patrick [University of Toronto, Department of Pathology, Mount Sinai Hospital, Toronto (Canada)

2009-08-15

We report a unique case of cobblestone complex using post-mortem MR and diffusion tensor imaging to assess the laminar organization of the fetal cerebrum. The imaging findings were correlated with autopsy findings. Abnormal cortical development in cobblestone complex resulted in disruption of normal laminar organization of the fetal brain, which was seen as interruption and nodularity of the high-signal T1 cortical band with increased anisotropy and medium diffusivity extending beyond the cortical band into the cerebral mantle on post-mortem MR and diffusion tensor imaging. (orig.)

Laminar Flame Speeds of Gasoline Surrogates Measured with the Flat Flame Method

KAUST Repository

Liao, Y.-H.; Roberts, William L.

2016-01-01

© 2016 American Chemical Society. The adiabatic, laminar flame speeds of gasoline surrogates at atmospheric pressure over a range of equivalence ratios of = 0.8-1.3 and unburned gas temperatures of 298-400 K are measured with the flat flame method

Optimal Sizing and Allocation of Residential Photovoltaic Panels in a Distribution Network for Ancillary Services Application

DEFF Research Database (Denmark)

Kordheili, Reza Ahmadi; Pourmousavi, Ali; Pillai, Jayakrishnan Radhakrishna

2014-01-01

requirements, such as voltage and current limits. This paper proposes an optimization method for determining the number of photovoltaic (PV) panels together with their arrangement in the grid in order to maximize ancillary service, without violating grid operation limits. The proposed optimization method...

Effect of aspect ratio on the laminar-to-turbulent transition in rectangular channel

International Nuclear Information System (INIS)

Wang Chang; Gao Puzhen; Tan Sichao; Xu Chao

2012-01-01

Highlights: ► Effect of aspect ratio on the transition Reynolds number in rectangular channel is studied. ► Prediction correlation for transition Reynolds number is proposed. ► The initiation location of flow transition is studied. - Abstract: The critical Reynolds number of the laminar-to-turbulent transition in the rectangular channel is investigated based on the energy gradient method. The results show that the critical Reynolds number decreases with the increasing aspect ratio. However, the relative location of laminar breakdown does not migrate significantly with the variation of the aspect ratio. In addition, a theoretical correlation as a function of the aspect ratio is proposed to calculate the transition Reynolds number, and the predicted values are in good agreement with the experimental data obtained in the published literatures.

Histopathological hoof laminar changes in horses with Pituitary Pars Intermedia Adenoma: cases report

Directory of Open Access Journals (Sweden)

L. M. Laskoski

2015-10-01

Full Text Available ABSTRACTLaminitis in horses is often associated with endocrine disorders, especially the pituitary pars intermedia dysfunction (PPID in older animals. Morphologic exams of the laminar tissue of the hoof were performed in two horses with suspected PPID, with no clinical signs of laminitis. Changes compatible with laminitis of endocrine origin were observed, such as rounding of the nuclei of the basal cells, thinning and stretching of the secondary epidermal laminae and tissue proliferation. PPID horses with no clinical signs of laminitis may be affected by lesions of the laminar tissue of the hoof that compromise the integrity of the dermal-epidermal junction and may develop clinical symptoms of the disease. It has been suggested that the development stage of endocrine laminitis is longer, but further studies should be conducted to confirm it.

Autoignited laminar lifted flames of methane/hydrogen mixtures in heated coflow air

KAUST Repository

Choi, Byungchul

2012-04-01

Autoignited lifted flame behavior in laminar jets of methane/hydrogen mixture fuels has been investigated experimentally in heated coflow air. Three regimes of autoignited lifted flames were identified depending on initial temperature and hydrogen to methane ratio. At relatively high initial temperature, addition of a small amount of hydrogen to methane improved ignition appreciably such that the liftoff height decreased significantly. In this hydrogen-assisted autoignition regime, the liftoff height increased with jet velocity, and the characteristic flow time - defined as the ratio of liftoff height to jet velocity - correlated well with the square of the adiabatic ignition delay time. At lower temperature, the autoignited lifted flame demonstrated a unique feature in that the liftoff height decreased with increasing jet velocity. Such behavior has never been observed in lifted laminar and turbulent jet flames. A transition regime existed between these two regimes at intermediate temperature. © 2011 The Combustion Institute.

Laminar pattern of cholinergic and adrenergic receptors in rat visual cortex using quantitative receptor autoradiography

International Nuclear Information System (INIS)

Schliebs, R.; Walch, C.

1989-01-01

The laminar distribution of muscarinic acetylcholine receptors, including the M1-receptor subtype, of beta-adrenergic receptors, and noradrenaline uptake sites, was studied in the adult rat visual, frontal, somatosensory and motor cortex, using quantitative receptor autoradiography. In the visual cortex, the highest density of muscarinic acetylcholine receptors was found in layer I. From layer II/III to layer V binding decreases continueously reaching a constant binding level in layers V and VI. This laminar pattern of muscarinic receptor density differs somewhat from that observed in the non-visual cortical regions examined: layer II/III contained the highest receptor density followed by layer I and IV: lowest density was found in layer V and VI. The binding profile of the muscarinic cholinergic M1-subtype through the visual cortex shows a peak in cortical layer II and in the upper part of layer VI, whereas in the non-visual cortical regions cited the binding level was high in layer II/III, moderate in layer I and IV, and low in layer VI. Layers I to IV of the visual cortex contained the highest beta-adrenergic receptor densities, whereas only low binding levels were observed in the deeper layers. A similar laminar distribution was found also in the frontal, somatosensory and motor cortex. The density of noradrenaline uptake sites was high in all layers of the cortical regions studied, but with noradrenaline uptake sites somewhat more concentrated in the superficial layers than in deeper ones. The distinct laminar pattern of cholinergic and noradrenergic receptor sites indicates a different role for acetylcholine and noradrenaline in the functional anatomy of the cerebral cortex, and in particular, the visual cortex. (author)

Laminar pattern of cholinergic and adrenergic receptors in rat visual cortex using quantitative receptor autoradiography

Energy Technology Data Exchange (ETDEWEB)

Schliebs, R; Walch, C [Leipzig Univ. (German Democratic Republic). Bereich Medizin; Stewart, M G [Open Univ., Milton Keynes (UK)

1989-01-01

The laminar distribution of muscarinic acetylcholine receptors, including the M1-receptor subtype, of beta-adrenergic receptors, and noradrenaline uptake sites, was studied in the adult rat visual, frontal, somatosensory and motor cortex, using quantitative receptor autoradiography. In the visual cortex, the highest density of muscarinic acetylcholine receptors was found in layer I. From layer II/III to layer V binding decreases continueously reaching a constant binding level in layers V and VI. This laminar pattern of muscarinic receptor density differs somewhat from that observed in the non-visual cortical regions examined: layer II/III contained the highest receptor density followed by layer I and IV: lowest density was found in layer V and VI. The binding profile of the muscarinic cholinergic M1-subtype through the visual cortex shows a peak in cortical layer II and in the upper part of layer VI, whereas in the non-visual cortical regions cited the binding level was high in layer II/III, moderate in layer I and IV, and low in layer VI. Layers I to IV of the visual cortex contained the highest beta-adrenergic receptor densities, whereas only low binding levels were observed in the deeper layers. A similar laminar distribution was found also in the frontal, somatosensory and motor cortex. The density of noradrenaline uptake sites was high in all layers of the cortical regions studied, but with noradrenaline uptake sites somewhat more concentrated in the superficial layers than in deeper ones. The distinct laminar pattern of cholinergic and noradrenergic receptor sites indicates a different role for acetylcholine and noradrenaline in the functional anatomy of the cerebral cortex, and in particular, the visual cortex. (author).

Extinction of counterflow premixed laminar flames

International Nuclear Information System (INIS)

Smooke, M.D.; Giovangigli, V.

1987-01-01

Problems in combustion and heat and mass transfer often depend upon one or more physical/chemical parameters. In many cases the combustion scientist is interested in knowing how the solution will behave if one or more of these parameters is varied. For some parameter regimes the governing equations can produce multiple solutions and the branches of the solution curve are linked via singular points. It is at these singular points, however that the system exhibits special behavior. To be able to predict the solution structure in the neighborhood of these points, the authors employ a phase-space, pseudo arclength, continuation method that utilizes Newton-like iterations and adaptive gridding techniques. The authors apply the method in the solution of counterflow premixed laminar flames

Utilização de hidrocortisona em eqüinos submetidos a isquemia e reperfusão no jejuno e suas conseqüências sobre o cório laminar Hydrocortisone in horses submitted to jejunal isquemia and reperfusion and its effects in the laminar corium

Directory of Open Access Journals (Sweden)

J.J.M. Rio Tinto

2004-06-01

Full Text Available Estudou-se o efeito da administração de succinato sódico de hidrocortisona (SSH no desenvolvimento de lesões no cório laminar de eqüinos. Doze animais foram submetidos à laparotomia sob anestesia geral e à isquemia total em dois segmentos do jejuno, enquanto três foram usados como controle. Após uma hora de isquemia, seis animais receberam 4,0mg/kg de SSH por via intravenosa (grupo T e seis receberam placebo (grupo NT. Após duas horas de isquemia foi restabelecido o fluxo de sangue local e, decorridas duas horas de reperfusão, foi realizada a laparorrafia e permitiu-se a recuperação anestésica. Após 12 horas do início da reperfusão, os animais foram sacrificados e deles colhidas amostras de tecido laminar para avaliação histomorfológica. As alterações avaliadas ao microscópio óptico foram quantificadas por escores que variaram de 0 a 3. Os escores para lesão no tecido laminar foram semelhantes nos animais dos grupos T (0,41 e NT (0,54, permitindo concluir que a hidrocortisona não acentuou as lesões produzidas no tecido laminar após a isquemia e reperfusão no jejuno.To evaluate whether hydrocortisone sodium succinate (HSS aggravates lesions in the laminar tissue secondary to intestinal ischemia and reperfusion (IR, two segments of the jejunum were isolated in 12 halothane-anesthetized horses, and total ischemia was induced on them. Three other horses were used as controls. One hour after the onset of the ischemia, HSS (4.0mg/kg was administered intravenously to six animals (T group and saline to the others (NT group. After two hours of ischemia and two hours of reperfusion the abdomen was closed and the horses were allowed to recover from anesthesia. After 12 hours of reperfusion the horses were euthanatized and biopsy specimens were taken from the laminar tissue and the lesions were evaluated and scored. No significant differences between T (0.41 and NT (0.54 groups for laminar lesion scores were observed. The

Laminar recordings in frontal cortex suggest distinct layers for maintenance and control of working memory.

Science.gov (United States)

Bastos, André M; Loonis, Roman; Kornblith, Simon; Lundqvist, Mikael; Miller, Earl K

2018-01-30

All of the cerebral cortex has some degree of laminar organization. These different layers are composed of neurons with distinct connectivity patterns, embryonic origins, and molecular profiles. There are little data on the laminar specificity of cognitive functions in the frontal cortex, however. We recorded neuronal spiking/local field potentials (LFPs) using laminar probes in the frontal cortex (PMd, 8A, 8B, SMA/ACC, DLPFC, and VLPFC) of monkeys performing working memory (WM) tasks. LFP power in the gamma band (50-250 Hz) was strongest in superficial layers, and LFP power in the alpha/beta band (4-22 Hz) was strongest in deep layers. Memory delay activity, including spiking and stimulus-specific gamma bursting, was predominately in superficial layers. LFPs from superficial and deep layers were synchronized in the alpha/beta bands. This was primarily unidirectional, with alpha/beta bands in deep layers driving superficial layer activity. The phase of deep layer alpha/beta modulated superficial gamma bursting associated with WM encoding. Thus, alpha/beta rhythms in deep layers may regulate the superficial layer gamma bands and hence maintenance of the contents of WM. Copyright © 2018 the Author(s). Published by PNAS.

DNS of Laminar-Turbulent Transition in Swept-Wing Boundary Layers

Science.gov (United States)

Duan, L.; Choudhari, M.; Li, F.

2014-01-01

Direct numerical simulation (DNS) is performed to examine laminar to turbulent transition due to high-frequency secondary instability of stationary crossflow vortices in a subsonic swept-wing boundary layer for a realistic natural-laminar-flow airfoil configuration. The secondary instability is introduced via inflow forcing and the mode selected for forcing corresponds to the most amplified secondary instability mode that, in this case, derives a majority of its growth from energy production mechanisms associated with the wall-normal shear of the stationary basic state. An inlet boundary condition is carefully designed to allow for accurate injection of instability wave modes and minimize acoustic reflections at numerical boundaries. Nonlinear parabolized stability equation (PSE) predictions compare well with the DNS in terms of modal amplitudes and modal shape during the strongly nonlinear phase of the secondary instability mode. During the transition process, the skin friction coefficient rises rather rapidly and the wall-shear distribution shows a sawtooth pattern that is analogous to the previously documented surface flow visualizations of transition due to stationary crossflow instability. Fully turbulent features are observed in the downstream region of the flow.

Experimental and computational study of scalar modes in a periodic laminar flow

NARCIS (Netherlands)

Baskan, O.; Speetjens, M.F.M.; Metcalfe, G.; Clercx, H.J.H.

2015-01-01

Scalar fields can evolve complex coherent structures under the action of periodic laminar flows. This comes about from the competition between chaotic advection working to create structure at ever finer length scales and diffusion working to eliminate fine-scale structure. Recently analysis of this

76 FR 36400 - Third-Party Provision of Ancillary Services; Accounting and Financial Reporting for New Electric...

Science.gov (United States)

2011-06-22

...-000 and AD10-13-000] Third-Party Provision of Ancillary Services; Accounting and Financial Reporting... Commission's accounting and financial reporting requirements currently do not contain specific accounting \\12... financial reporting requirements \\41\\ for public utilities \\42\\ are designed to provide information about a...

[Direct repair of adolescent lumbar spondylolysis using a pedicle screw-laminar hook system by paramedian approach].

Science.gov (United States)

Wang, Bin; Tang, Yong-hua; Tang, Hong-chao; Jin, Cai-yi

2011-08-01

To discuss the indication and clinical effect of direct repair of adolescent lumbar spondylolysis by screw-laminar hook system. From August 2003 to December 2008, 28 patients (13 males and 15 females,ranging in age from 15 and 26 years, averaged 21.6 years) with lumbar spondylolysis were treated with isthmic bone grafting and internal fixation with a pedicle screw-laminar hook system. Three patients had spondylolysis at L3, L4; 5 patients had spondylolysis at L4, L5; 8 patients had spondylolysis at L4; and 12 patients had spondylolysis at L5. All the patients had low back pain and lasted over 6 months. According to preoperative and postoperative plain radiograph, CT scan and Macnab criteria, the fusion rate and clinical effect of this technique were evaluated. All the patients were followed up with a mean period of 14.9 months, ranging from 9 to 24 months. All the patients had bony union according to the X-rays and CT scan. According to the calculation results of Macnab criteria, 22 patients got an excellent result, 5 good and 1 fair. The direct repair of adolescent lumbar spondylolysis with pedicle screw-laminar hook system can shorten length of operation,decrease blood loss, preserve more posterior structures of spine and avoid iatrogenic instability of spine. The postoperative immediate stability of vertebral segment is acquired and the mobility of adjacent intervertebral discs is reserved. The screw-laminar hook system for the treatment of adolescent spondylolisthesis can get satisfactory clinical results.

Simulation of hypersonic shock wave - laminar boundary layer interactions

Science.gov (United States)

Kianvashrad, N.; Knight, D.

2017-06-01

The capability of the Navier-Stokes equations with a perfect gas model for simulation of hypersonic shock wave - laminar boundary layer interactions is assessed. The configuration is a hollow cylinder flare. The experimental data were obtained by Calspan-University of Buffalo (CUBRC) for total enthalpies ranging from 5.07 to 21.85 MJ/kg. Comparison of the computed and experimental surface pressure and heat transfer is performed and the computed §ow¦eld structure is analyzed.

Magnus effect on laminar flow around a rotating cylinder

International Nuclear Information System (INIS)

Amarante, J.C.A.

1989-01-01

The laminar flow around a rotating cylinder is studied, through the numerical solution of the full Navier-Stokes equations, for Reynolds number, based on cylinder radius, varying between 0.5 and 25 and for non-dimensional tangential velocities of the body surface between zero and 8. The Taylor and Hughes method is employed in the theoretical investigation. The Magnus lift coefficient and the drag coefficient are obtained and the presure and vorticity distribution are calculated. (author)

INCOMPRESSIBLE LAMINAR BOUNDARY LAYER CONTROL BY BLOWING AND SUCTION

OpenAIRE

AZZEDINE NAHOUI; LAKHDAR BAHI

2013-01-01

A two-dimensional incompressible laminar boundary layer and its control using blowing and suction over a flat plate and around the NACA 0012 and 661012 profiles, is studied numerically. The study is based on the Prandtl boundary layer model using the finite differences method and the Crank-Nicolson scheme. The velocity distribution, the boundary layer thickness and the friction coefficient, are determined and presented with and without control. The application of the control technique, has de...

Experimental analysis of colloid capture by a cylindrical collector in laminar overland flow.

Science.gov (United States)

Wu, Lei; Gao, Bin; Muñoz-Carpena, Rafael

2011-09-15

Although colloid-facilitated contaminant transport in water flow is a well-known contamination process, little research has been conducted to investigate the transport of colloidal particles through emergent vegetation in overland flow. In this work, a series of laboratory experiments were conducted to measure the single-collector contact efficiency (η(0)) of colloid capture by a simulated plant stem in laminar lateral flow. Fluorescent microspheres of various sizes were used as experimental colloids. The colloid suspensions were applied to a glass cylinder installed in a small size flow chamber at different flow rates. Two cylinder sizes were tested in the experiment and silicone grease was applied to the cylinder surface to make it favorable for colloid deposition. Our results showed that increases in flow rate and collector size reduced the value of η(0) and a minimum value of η(0) might exist for a colloid size. The experimental data were compared to theoretical predictions of different single-collector contact efficiency models. The results indicated that existing single-collector contact efficiency models underestimated the η(0) of colloid capture by the cylinders in laminar overland flow. A regression equation of η(0) as a function of collector Reynolds number (Re(c)) and Peclet number (N(Pe)) was developed and fit the experimental data very well (R(2) > 0.98). This regression equation can be used to help construct and refine mathematical models of colloid transport and filtration in laminar overland flow on vegetated surfaces.

Enhancing the Role of Electric Vehicles in the Power Grid: Field Validation of Multiple Ancillary Services

DEFF Research Database (Denmark)

Knezovic, Katarina; Martinenas, Sergejus; Andersen, Peter Bach

2016-01-01

essentially means it is applicable to any EV complying with IEC 61851 and SAE J1772 standards. The field test validation is conducted in a real Danish distribution grid with a Nissan Leaf providing three ancillary services through unidirectional AC charging, namely congestion management, local voltage support...

Pipe stress analysis on HCCR-TBS ancillary systems in conceptual design

International Nuclear Information System (INIS)

Ahn, Mu-Young; Cho, Seungyon; Lee, Eo Hwak; Park, Yi-Hyun; Lee, Youngmin

2016-01-01

Highlights: • Pipe stress is performed on Korean HCCR-TBS for the load combinations including seismic events. • The resultant stress meets the requirement of the design code & standard except one position where modification is needed. • The results gives useful information for the design evolution in the next desgin phase. - Abstract: Korean Helium Cooled Ceramic Reflector (HCCR) Test Blanket System (TBS) will be tested in ITER to demonstrate feasibility of the breeding blanket concept. The HCCR-TBS comprises Test Blanket Module (TBM) with associated shield, and ancillary systems located in various positions of ITER building. Currently, conceptual design for the HCCR-TBS is in progress. This paper presents pipe stress analysis results for the HCCR-TBS ancillary systems. The pipe stress analysis was performed in accordance with ASME B31.3 for major pipes of the Helium Cooling System (HCS) and the Coolant Purification System (CPS), which are operated in high pressure and temperature. The pipe stress for various load cases and load combinations were calculated. Operational pressure and temperature during plasma operation are applied as pressure load and thermal load, respectively. In addition seismic events were combined to investigate the code compliance for sustained load case and occasional load case. It was confirmed that the resultant stress meets the requirements of ASME B31.3 except one position in which it needs modification. These results give useful information for the next design phase, for example, nozzle loads for the component selection, the support design parameters, etc.

Pipe stress analysis on HCCR-TBS ancillary systems in conceptual design

Energy Technology Data Exchange (ETDEWEB)

Ahn, Mu-Young, E-mail: myahn74@nfri.re.kr [National Fusion Research Institute, Daejeon (Korea, Republic of); Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of); Lee, Eo Hwak [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Yi-Hyun; Lee, Youngmin [National Fusion Research Institute, Daejeon (Korea, Republic of)

2016-11-01

Highlights: • Pipe stress is performed on Korean HCCR-TBS for the load combinations including seismic events. • The resultant stress meets the requirement of the design code & standard except one position where modification is needed. • The results gives useful information for the design evolution in the next desgin phase. - Abstract: Korean Helium Cooled Ceramic Reflector (HCCR) Test Blanket System (TBS) will be tested in ITER to demonstrate feasibility of the breeding blanket concept. The HCCR-TBS comprises Test Blanket Module (TBM) with associated shield, and ancillary systems located in various positions of ITER building. Currently, conceptual design for the HCCR-TBS is in progress. This paper presents pipe stress analysis results for the HCCR-TBS ancillary systems. The pipe stress analysis was performed in accordance with ASME B31.3 for major pipes of the Helium Cooling System (HCS) and the Coolant Purification System (CPS), which are operated in high pressure and temperature. The pipe stress for various load cases and load combinations were calculated. Operational pressure and temperature during plasma operation are applied as pressure load and thermal load, respectively. In addition seismic events were combined to investigate the code compliance for sustained load case and occasional load case. It was confirmed that the resultant stress meets the requirements of ASME B31.3 except one position in which it needs modification. These results give useful information for the next design phase, for example, nozzle loads for the component selection, the support design parameters, etc.

Heat transfer of pulsating laminar flow in pipes with wall thermal inertia

International Nuclear Information System (INIS)

Yuan, Hongsheng; Tan, Sichao; Wen, Jing; Zhuang, Nailiang

2016-01-01

The effects of wall thermal inertia on heat transfer of pulsating laminar flow with constant power density within the pipe wall are investigated theoretically. The energy equation of the fully developed flow and heat transfer is solved by separation of variables and Green's function. The effects of the pulsation amplitude and frequency, the Prandtl number and the wall heat capacity on heat transfer features characterized by temperature, heat flux and Nusselt number are analyzed. The results show that the oscillation of wall heat flux increases along with the wall thermal inertia, while the oscillation of temperature and Nusselt number is suppressed by the wall thermal inertia. The influence of pulsation on the average Nusselt number is also obtained. The pulsating laminar flow can reduce the average Nusselt number. The Nusselt number reduction of pipe flow are a little more remarkable than that of flow between parallel plates, which is mainly caused by differences in hydraulic and thermal performances of the channels. (authors)

Ancillary care in public health intervention research in low-resource settings: researchers' practices and decision-making.

Science.gov (United States)

Taylor, Holly A; Merritt, Maria W; Mullany, Luke C

2011-09-01

Little is known about researchers' practices regarding the provision of ancillary care (AC) in public health intervention studies they have conducted and the factors that influence their decisions about whether to provide ancillary care in low-resource settings. We conducted 52 in-person in-depth interviews with public health researchers. Data analysis was iterative and led to the identification of themes and patterns among themes. We found that researchers who conduct their research in the community setting are more likely to identify and plan for the AC needs of potential research subjects before a study begins, whereas those affiliated with a permanent facility are more likely to deliver AC to research subjects on an ad hoc basis. Our findings suggest that on the whole, at least for public health intervention research in low-resource settings, researchers conducting research in the community setting confront more complex ethical and operational challenges in their decision-making about AC than do researchers conducting facility-based studies.

A framework for cost-based pricing of transmission and ancillary services in competitive electric power markets

International Nuclear Information System (INIS)

Zobian, A.; Ilic, M.D.

1995-01-01

In this paper the authors propose a framework for accurate cost determination and pricing of transmission and ancillary services in competitive electric power markets. The proposed framework is based on their anticipation of the evolving environment and industry structure. They envision the future as a competitive energy market with a centralized control entity that coordinates system activities, prices transmission and ancillary services and controls various system resources. This control entity has control over a certain (pre-defined) geographical area. It is proposed that the system operation and control be kept as they are currently done in control centers, no major change in these functions is required for the proposed pricing strategy. The pricing strategy is divided into two main classes based on time scale separation and firmness, short and long term, firm and interruptible contracts. The approach is based on superposition of different transaction on the network, and a three-part tariff design. The charges are directly related to the impact of each transaction on the system

Numerical Investigation of Laminar Diffusion Flames Established on a Horizontal Flat Plate in a Parallel Air Stream

Directory of Open Access Journals (Sweden)

E. D. Gopalakrishnan

2011-06-01

Full Text Available Numerical investigation of laminar diffusion flames established on a flat plate in a parallel air stream is presented. A numerical model with a multi-step chemical kinetics mechanism, variable thermo-physical properties, multi-component species diffusion and a radiation sub-model is employed for this purpose. Both upward and downward injection of fuel has been considered in a normal gravity environment. The thermal and aerodynamic structure of the flame has been explained with the help of temperature and species contours, net reaction rate of fuel and streamlines. Flame characteristics and stability aspects for several air and fuel velocity combinations have been studied. An important characteristic of a laminar boundary layer diffusion flame with upward injection of fuel is the velocity overshoot that occurs near the flame zone. This is not observed when the fuel is injected in the downward direction. The flame standoff distance is slightly higher for the downward injection of fuel due to increase in displacement thickness of boundary layer. Influence of an obstacle, namely the backward facing step, on the flame characteristics and stability aspects is also investigated. Effects of air and fuel velocities, size and location of the step are studied in detail. Based on the air and fuel velocities, different types of flames are predicted. The use of a backward-facing step as a flame holding mechanism for upward injection of fuel, results in increased stability limits due to the formation of a recirculation zone behind the step. The predicted stability limits match with experimentally observed limits. The step location is seen to play a more important role as compared to the step height in influencing the stability aspects of flames.

Combustion and radiation modeling of laminar premixed flames using OpenFOAM: A numerical investigation of radiative heat transfer in the RADIADE project

DEFF Research Database (Denmark)

Haider, Sajjad; Pang, Kar Mun; Ivarsson, Anders

2013-01-01

This paper presents the computational fluid dynamics modelling of a laminar premixed flame. A specific solver named ’rareLTSFoam’ is developed using OpenFOAM ® code. The solver is used to simulate experimental stoichiometric and rich laminar premixed flames. The modelling is carried out for thermal...

Laminar-Turbulent transition on Wind Turbines

DEFF Research Database (Denmark)

Martinez Hernandez, Gabriel Gerardo

The present thesis deals with the study of the rotational effects on the laminar-turbulent transition on wind turbine blades. Linear stability theory is used to formulate the stability equations that include the effect of rotation. The mean flow required as an input to stability computations...... parametrized and adapted to an wind turbine rotor geometry. The blade is resolved in radial sections along which calculations are performed. The obtained mean flow is classified according to the parameters used on the rotating configuration, geometry and operational conditions. The stability diagrams have been...... to define the resultant wave magnitude and direction. The propagation of disturbances in the boundary layers in three dimensional flows is relatively a complicated phenomena. The report discusses the available methods and techniques used to predict the transition location. Some common wind turbine airfoils...

Stress and vascular responses: atheroprotective effect of laminar fluid shear stress in endothelial cells: possible role of mitogen-activated protein kinases.

Science.gov (United States)

Yoshizumi, Masanori; Abe, Jun-Ichi; Tsuchiya, Koichiro; Berk, Bradford C; Tamaki, Toshiaki

2003-03-01

Atherosclerosis preferentially occurs in areas of turbulent blood flow and low fluid shear stress, whereas laminar blood flow and high shear stress are atheroprotective. Inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha), stimulate expression of endothelial cell (EC) genes that may promote atherosclerosis. Recent findings suggest a steady laminar blood flow decreases EC apoptosis and inhibits TNF-mediated EC activation. EC apoptosis or activation is suggested to be involved in plaque erosion, which may lead to platelet aggregation. TNF-alpha regulates gene expression in ECs, in part, by stimulating mitogen-activated protein (MAP) kinases, which phosphorylate transcription factors. We hypothesized that steady laminar flow inhibits cytokine-mediated activation of MAP kinases in ECs. To test this hypothesis, we determined the effects of steady laminar flow (shear stress = 12 dynes/cm(2)) on TNF-alpha-stimulated activity of three MAP kinases in human umbilical vein ECs (HUVEC): extracellular signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK), and p38. TNF-alpha activated ERK1/2, JNK, and p38 maximally at 15 min in HUVEC. Pre-exposing HUVEC for 10 min to flow inhibited TNF-alpha activation of JNK, but showed no significant effect on ERK1/2 or p38 activation. Incubation of HUVEC with PD98059, a specific ERK1/2 inhibitor, blocked the flow-mediated inhibition of TNF activation of JNK. Transfection studies with dominant-negative constructs of the protein kinase MEK5 suggested an important role for big mitogen-activated protein kinase 1 (BMK1) in flow-mediated regulation of EC activation by TNF-alpha. Understanding the mechanisms by which steady laminar flow regulates JNK activation by cytokines may provide insight into the atheroprotective mechanisms induced by laminar blood flow.

Vertical Keiretsu and International Market Entry: The Case of the Japanese Automobile Ancillary Industry

OpenAIRE

Kunal Banerji; Rakesh B Sambharya

1996-01-01

This study investigated whether small Japanese automobile ancillary firms followed the major Japanese automakers in setting up production facilities in the United States. Based on Dunning's eclectic theory of foreign direct investment and resource dependence theory, hypotheses were generated to explain the determinants of foreign investment of Japanese suppliers. It was hypothesized that mutual dependencies between the major Japanese automobile firms and their suppliers, firm-specific ownersh...

Proposal for the study of laminar relativistic electron beam generation by a foilless diode

International Nuclear Information System (INIS)

Jones, M.E.; Thode, L.E.

1979-02-01

The continuation of an analytical and numerical study of intense relativistic electron beam generation by foilless diodes is proposed. The investigation is aimed at optimizing the diode design to produce a laminar flow

Exogam with its ancillary detectors

International Nuclear Information System (INIS)

Theisen, Ch.

2004-01-01

The goal of the meeting was to discuss the status of experiments using Exogam and its ancillary detectors. Presentations include details of experiments already run and those in preparation. This document gathers most of the slides presented at the meeting. The results of 7 experiments are described. There are 9 contributions as it follows: 1) presentation of the Vamos spectrometer p.1-15, 2) the Clara (detector) and Prisma (spectrometer) setup: status and perspectives p.16-33, 3) experiment E344aS: shape coexistence near the N=Z line and collective properties of Kr isotopes investigated by low-energy Coulomb excitation p.34-56, 4) experiment E389: study of effective charges at Sm 100 via the nuclear lifetime measurements in Pd 96 and Cd 98 p.57-68, 5) experiment E375: spectroscopy of trans-fermium nuclei p.69-91, 6) experiment E408S: He 8 on Pb 208 and Bi 209 p.92-102, 7) experiment E462: very neutron rich calcium isotopes at N=32, structure of magic Ca 54 studied by gamma-spectroscopy with deep inelastic reactions p.103-115, 8) experiment E451: searching for T=D pairing and a new coupling scheme in Pd 92 and Ru 88 p.116-141, and 9) experiment E404aS: identification of gamma rays in nuclei around the drip-line nucleus Sm 130 , probing the maximally deformed light rare earth region

Full-thickness thoracic laminar erosion after posterior spinal fusion associated with late-presenting infection.

Science.gov (United States)

Tribus, Clifford B; Garvey, Kathleen E

2003-05-15

A case report describes unilateral complete laminar erosion of the caudal thoracic spine and late-presenting infection in a patient 10 years after anteroposterior reconstruction for scoliosis. To present an unusual but significant complication that may occur after implantation of spinal instrumentation. The reported patient presented with a deep infection and persistent back pain 10 years after successful anteroposterior reconstruction for adult idiopathic scoliosis. Delayed onset infections after implantation of spinal instrumentation are infrequent, yet when present, often require hardware removal. The case of a 51-year-old woman who underwent irrigation and debridement for a late-presenting infection and removal of posterior hardware 10 years after her index procedure is presented. Interoperatively, it was noted that full-thickness laminar erosion was present from T4 to T12. The patient was taken to the operating room for wound irrigation, debridement, and hardware removal. It was discovered that a Cotrel-Dubousset rod placed on the convexity of the curve had completely eroded through the lamina of T7-T12. Infectious material was found along the entire length of both the convex and concave Cotrel-Dubousset rods. Intraoperative cultures grew Staphylococcus epidermidis and Propionibacterium acnes. Intravenous and oral antibiotics were administered, resulting in resolution of the infection and preoperative pain. The exact role of late-presenting infection with regard to the laminar erosion and rod migration seen in this case remains to be elucidated. However, the authors believe the primary cause of bony erosion was mechanical in origin. Regardless, most spine surgeons will treat many patients who have had posterior spinal implants and will perform hardware removal on a significant number of these patients during their careers. A full-thickness laminar erosion exposes the spinal cord to traumatic injury during hardware removal and debridement. This case is

MR imaging diagnosis of posterior cruciate ligament injury: importance of ancillary findings

International Nuclear Information System (INIS)

Hwang, Kang Ik; Lee, Jong Hwa; Kim, Young Sun; Lee, Jung Hwoi; Ki, Tae Sung; Park, Jong Oag

1997-01-01

To evaluate the importance of two ancillary findings of anterior tibial plateau bruise/fracture and popliteus muscle strain on MR diagnosis of posterior cruicate ligament injury. We retrospectively evaluated 48 patients with confirmed posterior cruciate ligament tear. We studied the incidence of anterior tibial plateau injury and popliteus muscle strain, and the specificity of popliteus muscle strain with or without bony injury. A complete tear of the posterior cruciate ligament was noted in 37 cases, a partial tear in 11. Anterior tibial plateau lesion was found in 21 of 48 cases (44%); This total was made up of 17/37 PCL complete tears (46%) and 4/11 partial tears (36%). The difference in the incidence of complete and partial tears is not statistically significant. Popliteus muscle injury was found in 20 of 48 cases (42%), the total consisted of 19/37 PCL complete tears (51%) and 1/11 partial tears (10%). The incidence of 42% is relatively high, approximating that of bony injury. The difference in the incidence of complete and partial tears is statistically significant (p < 0.006). Specificity for posterior cruciate ligament tear is 69%(20/29), and when concomitant with anterior tibial plateau injury is 94%(16/17). As in the case of anterior cruciate ligament injury, these documented ancillary findings of anterior tibial plateau and popliteus muscle injuries are very helpful when MR diagnosis of posterior cruciate ligament injury itself and differentiation of partial and complete rupture are doubtful

Open Automated Demand Response Communications in Demand Response for Wholesale Ancillary Services

Energy Technology Data Exchange (ETDEWEB)

Kiliccote, Sila; Piette, Mary Ann; Ghatikar, Girish; Koch, Ed; Hennage, Dan; Hernandez, John; Chiu, Albert; Sezgen, Osman; Goodin, John

2009-11-06

The Pacific Gas and Electric Company (PG&E) is conducting a pilot program to investigate the technical feasibility of bidding certain demand response (DR) resources into the California Independent System Operator's (CAISO) day-ahead market for ancillary services nonspinning reserve. Three facilities, a retail store, a local government office building, and a bakery, are recruited into the pilot program. For each facility, hourly demand, and load curtailment potential are forecasted two days ahead and submitted to the CAISO the day before the operation as an available resource. These DR resources are optimized against all other generation resources in the CAISO ancillary service. Each facility is equipped with four-second real time telemetry equipment to ensure resource accountability and visibility to CAISO operators. When CAISO requests DR resources, PG&E's OpenADR (Open Automated DR) communications infrastructure is utilized to deliver DR signals to the facilities energy management and control systems (EMCS). The pre-programmed DR strategies are triggered without a human in the loop. This paper describes the automated system architecture and the flow of information to trigger and monitor the performance of the DR events. We outline the DR strategies at each of the participating facilities. At one site a real time electric measurement feedback loop is implemented to assure the delivery of CAISO dispatched demand reductions. Finally, we present results from each of the facilities and discuss findings.

Modeling of confined and unconfined laminar premixed flames on slit and tube burners

NARCIS (Netherlands)

Mallens, R.M.M.; Lange, de H.C.; Ven, van de C.J.H.; Goey, de L.P.H.

1995-01-01

A model is presented for laminar premixed Bunsen flames on slit and cylindrical burners burning in a surrounding atmosphere. A comparison between modeling and experimental results shows that the model can reproduce the experimental results within 10% accuracy. The influence of a surrounding

Mapeamento do potencial de erosão laminar na bacia do rio Japaratuba, SE, via SIG Mapping the laminar erosion potential for the Japaratuba river basin, SE via GIS

Directory of Open Access Journals (Sweden)

Ricardo de Aragão

2011-07-01

Full Text Available A erosão do solo é a principal causa do empobrecimento precoce de terras produtivas e dentre as suas formas está a erosão laminar. Esta se caracteriza não apenas pela remoção de uma camada relativamente uniforme da superfície, mas também por seus nutrientes, sendo intensificada, portanto, pelas ações antrópicas. Para evitar ou reduzir seus impactos, fazem-se necessárias diretrizes para a adequação do uso e da ocupação às condições de cobertura vegetal, tipo de solo e topografia, através de mapas do potencial erosivo laminar da região de interesse, obtidos via sistemas de informações geográficas (SIG. Neste trabalho foi desenvolvido o mapeamento do potencial erosivo laminar da bacia do rio Japaratuba, SE (1685 km²; trata-se de uma região sujeita a intensa atividade agrícola, pecuária e de mineração, onde só restam 6% da vegetação nativa. Os resultados mostram que 48,71% da área da bacia ficam nas classes de médio e alto potencial erosivo, indicando que a bacia está bastante impactada devido aos usos inadequados para as condições de solo e declividades.Soil erosion is a natural phenomenon that reduces soil fertility and causes a great impact on agricultural areas. Laminar erosion is characterized by the removal of the top soil fairly uniformly as well as its nutrients, which is accelerated by human activities. To minimize the impacts it is necessary to adopt an adequate soil management that takes into account the type of the soil, relief, and vegetation cover. The soil management can be aided by mapping the erosive potential of a region using GIS tools. In this work, the technique that was used for mapping the erosive potential in the Japaratuba River Basin (1685 km² located in the State of Sergipe is presented. The results show that 48.71% of the basin area lie within medium and high erosive potentials zones, suggesting the inadequate land use for the soil types and relief within the basin.

Numerical Heat Transfer Prediction for Laminar Flow in a Circular Pipe with a 90° Bend

Science.gov (United States)

Patro, Pandaba; Rout, Ani; Barik, Ashok

2018-06-01

Laminar air flow in a 90° bend has been studied numerically to investigate convective heat transfer, which is of practical relevance to electronic systems and refrigeration piping layout. CFD simulations are performed for Reynolds number in the range 200 to 1000 at different bend radius ratios (5, 10 and 20). The heat transfer characteristics are found to be enhanced in the curved pipe compared to a straight pipe, which are subjected to the same flow rate. The curvature and buoyancy effectively increase heat transfer in viscous laminar flows. The correlation between the flow structure and the heat transfer is found to be strong.

Use of laminar flow patterning for miniaturised biochemical assays

DEFF Research Database (Denmark)

Regenberg, Birgitte; Krühne, Ulrich; Beyer, M.

2004-01-01

Laminar flow in microfluidic chambers was used to construct low (one dimensional) density arrays suitable for miniaturized biochemical assays. By varying the ratio of flows of two guiding streams flanking a sample stream, precise focusing and positioning of the latter was achieved, and reactive s...... species carried in the sample stream were deposited on functionalized chip surfaces as discrete 50 mm wide lanes. Using different model systems we have confirmed the method's suitability for qualitative screening and quantification tasks in receptor-ligand assays, recording biotin...

Psychosocial Factors in the Relationship between Socioeconomic Status and Cardiometabolic Risk: the HCHS/SOL Sociocultural Ancillary Study.

Science.gov (United States)

McCurley, Jessica L; Penedo, Frank; Roesch, Scott C; Isasi, Carmen R; Carnethon, Mercedes; Sotres-Alvarez, Daniela; Schneiderman, Neil; Gonzalez, Patricia; Chirinos, Diana A; Camacho, Alvaro; Teng, Yanping; Gallo, Linda C

2017-08-01

U.S. Hispanics/Latinos display a high prevalence of metabolic syndrome (MetSyn), a group of co-occurring cardiometabolic risk factors (abdominal obesity, impaired fasting glucose, dyslipidemia, elevated blood pressure) associated with higher cardiovascular disease and mortality risk. Low socioeconomic status (SES) is associated with higher risk for MetSyn in Hispanics/Latinos, and psychosocial factors may play a role in this relationship. This cross-sectional study examined psychosocial factors in the association of SES and MetSyn components in 4,996 Hispanic/Latino adults from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) Sociocultural Ancillary Study. MetSyn components were measured at the baseline examination. Participants completed interviews to determine psychosocial risks (e.g., depression) and resources (e.g., social support) within 9 months of baseline (psychosocial indicators, and three factors for MetSyn [blood pressure, lipids, metabolic factors]. SEMs showed that lower SES was related to MetSyn factors indirectly through higher psychosocial risk/lower resources (Y-Bχ 2 (df = 420) = 4412.90, p psychosocial risk/resource variables (Mackinnon's 95% asymmetric CI = -0.13 to -0.02). SES is related to metabolic variables indirectly through psychosocial factors in U.S. Hispanics/Latinos of diverse ancestries.

Mathematical modeling for laminar flow of power law fluid in porous media

Energy Technology Data Exchange (ETDEWEB)

Silva, Renato A.; Mesquita, Maximilian S. [Universidade Federal do Espirito Santo (UFES), Sao Mateus, ES (Brazil). Centro Universitario Norte do Espirito Santo. Dept. de Engenharias e Computacao

2010-07-01

In this paper, the macroscopic equations for laminar power-law fluid flow is obtained for a porous medium starting from traditional equations (Navier-Stokes). Then, the volume averaging is applied in traditional transport equations with the power-law fluid model. This procedure leads to macroscopic transport equations set for non-Newtonian fluid. (author)

Removal Action Workplan for the 105-DR and 105-F Building Interim Safe Storage Projects and Ancillary Buildings

International Nuclear Information System (INIS)

Rodovsky, T. J.

1999-01-01

This document is the removal action workplan (RAW) for the 105-DR and 105-F Reactor Buildings and ancillary facilities. These buildings and facilities are located in the 100-D/DR and 100-F Areas of the Hanford Site in Benton County, Washington, which is owned and operated by the U.S. Department of Energy (DOE). The 100 Areas (including 100-D/DR and 100-F Areas) of the Hanford Site were placed on the U.S. Environmental Protection Agency's (EPA) National Priorities List under the Comprehensive Environmental Response, Compensation,and Liability Act of 1980 (CERCLA). DOE has determined that hazardous substances in the 105-DR and 105-F Reactor Buildings and four ancillary facilities present a potential threat to human health or the environment DOE has also determined that a non-time critical removal action is warranted at these facilities

Modelling Aṣṭādhyāyī: An Approach Based on the Methodology of Ancillary Disciplines (Vedāṅga)

Science.gov (United States)

Mishra, Anand

This article proposes a general model based on the common methodological approach of the ancillary disciplines (Vedāṅga) associated with the Vedas taking examples from Śikṣā, Chandas, Vyākaraṇa and Prātiśā khya texts. It develops and elaborates this model further to represent the contents and processes of Aṣṭādhyāyī. Certain key features are added to my earlier modelling of Pāṇinian system of Sanskrit grammar. This includes broader coverage of the Pāṇinian meta-language, mechanism for automatic application of rules and positioning the grammatical system within the procedural complexes of ancillary disciplines.

Analytical solutions of heat transfer for laminar flow in rectangular channels

Directory of Open Access Journals (Sweden)

Rybiński Witold

2014-12-01

Full Text Available The paper presents two analytical solutions namely for Fanning friction factor and for Nusselt number of fully developed laminar fluid flow in straight mini channels with rectangular cross-section. This type of channels is common in mini- and microchannel heat exchangers. Analytical formulae, both for velocity and temperature profiles, were obtained in the explicit form of two terms. The first term is an asymptotic solution of laminar flow between parallel plates. The second one is a rapidly convergent series. This series becomes zero as the cross-section aspect ratio goes to infinity. This clear mathematical form is also inherited by the formulae for friction factor and Nusselt number. As the boundary conditions for velocity and temperature profiles no-slip and peripherally constant temperature with axially constant heat flux were assumed (H1 type. The velocity profile is assumed to be independent of the temperature profile. The assumption of constant temperature at the channel’s perimeter is related to the asymptotic case of channel’s wall thermal resistance: infinite in the axial direction and zero in the peripheral one. It represents typical conditions in a minichannel heat exchanger made of metal.

Spalart–Allmaras model apparent transition and RANS simulations of laminar separation bubbles on airfoils

International Nuclear Information System (INIS)

Crivellini, Andrea; D’Alessandro, Valerio

2014-01-01

Highlights: • RANS simulation of laminar separation bubbles. • Spalart–Allamaras unexpected capability. • Straightforward implementation of our SA modifications. • Applications of a high order DG incompressible solver. - Abstract: The present paper deals with the Reynolds Averaged Navier–Stokes (RANS) simulation of Laminar Separation Bubble (LSB). This phenomenon is of large interest in several engineering fields, such as the study of wind turbines, unmanned aerial vehicles (UAV) and micro-air vehicles (MAV) characterized by a low operating Reynolds number. In such contexts a laminar boundary layer separation followed by a turbulent transition and afterwards by a turbulent reattachment may appear in the flow-field. The main novelty of this work is that an almost standard Spalart–Allmaras (SA) model, without additional equations for transition modeling, was successfully employed. The result achieved is very surprising being the model not developed for this purpose, but for fully-turbulent flows or for cases with imposed transition location. This result is of large interest, since the SA model is widely used in commercial, open-source and research codes. However, our approach cannot be advocated to predict natural transition within an attached boundary layer, indeed it is only able to deal with transitions triggered by a separated flow. The reliability and accuracy of our approach are here proved computing, by means of a high-order Discontinuous Galerkin (DG) incompressible solver, the flow-field over two airfoils at different flow regimes showing the formation of a LSB

A hybrid PSO technique for procuring VAR ancillary service in the deregulated electricity markets

Energy Technology Data Exchange (ETDEWEB)

El-Araby, E.E. [Department of Electrical Engineering, Suez Canal University (Egypt); Yorino, Naoto [Department of Artificial Complex Systems Engineering, Hiroshima University (Japan)

2010-07-15

This paper develops a new market-based technique for acquiring VAR ancillary service in the electricity market. The main objective of the developed market is to enable transmission operator ''TO'' to procure VAR service in a long term contract from the critical VAR providers that satisfy minimum VAR service payment while maintaining system security. Reactive power control problem for voltage stability is introduced into the VAR market problem in an explicit manner for normal and emergency states. An integration of particle swarm optimization ''PSO'' is presented with successive linear programming ''SLP'' for dealing with the VAR ancillary service problem. The problem is formulated as a large-scale nonlinear constrained optimization problem with a non-differentiable objective function representing VAR payment and operational costs. This type of problem is hard to be treated straightforwardly by the classical optimization methods. Therefore, we propose here a two-layer hybrid PSO/SLP approach, which is suited for carrying out the difficulties associated with non-differentiable and discontinuous objective functions. The proposed method has been examined on the standard IEEE 57 bus-system and compared with GA/SLP method to demonstrate its capability. (author)

Laminar Flame Speeds of Gasoline Surrogates Measured with the Flat Flame Method

KAUST Repository

Liao, Y.-H.

2016-01-27

© 2016 American Chemical Society. The adiabatic, laminar flame speeds of gasoline surrogates at atmospheric pressure over a range of equivalence ratios of = 0.8-1.3 and unburned gas temperatures of 298-400 K are measured with the flat flame method, which produces a one-dimensional flat flame free of stretch. Surrogates used in the current work are the primary reference fuels (PRFs, mixtures of n-heptane and isooctane), the toluene reference fuels (TRFs, mixtures of toluene and PRFs), and the ethanol reference fuels (ERFs, mixtures of ethanol and PRFs). In general, there is good agreement between the present work and the literature data for single-component fuel and PRF mixtures. Surrogates of TRF mixtures are found to exhibit comparable flame speeds to a real gasoline, while there is discrepancy observed between isooctane and gasoline. Moreover, the laminar flame speeds of TRF mixtures with similar fractions of n-heptane are found to be insensitive to the quantity of toluene in the mixture. Mixtures of ERFs exhibit comparable flame speeds to those of TRFs with similar mole fractions of n-heptane and isooctane.

Suppression of endothelial t-PA expression by prolonged high laminar shear stress

International Nuclear Information System (INIS)

Ulfhammer, Erik; Carlstroem, Maria; Bergh, Niklas; Larsson, Pia; Karlsson, Lena; Jern, Sverker

2009-01-01

Primary hypertension is associated with an impaired capacity for acute release of endothelial tissue-type plasminogen activator (t-PA), which is an important local protective response to prevent thrombus extension. As hypertensive vascular remodeling potentially results in increased vascular wall shear stress, we investigated the impact of shear on regulation of t-PA. Cultured human endothelial cells were exposed to low (≤1.5 dyn/cm 2 ) or high (25 dyn/cm 2 ) laminar shear stress for up to 48 h in two different experimental models. Using real-time RT-PCR and ELISA, shear stress was observed to time and magnitude-dependently suppress t-PA transcript and protein secretion to approximately 30% of basal levels. Mechanistic experiments revealed reduced nuclear protein binding to the t-PA specific CRE element (EMSA) and an almost completely abrogated shear response with pharmacologic JNK inhibition. We conclude that prolonged high laminar shear stress suppresses endothelial t-PA expression and may therefore contribute to the enhanced risk of arterial thrombosis in hypertensive disease.

Effective thermal conductivity of superfluid helium: laminar, turbulent and ballistic regimes

Directory of Open Access Journals (Sweden)

Sciacca Michele

2016-06-01

Full Text Available In this paper we extend previous results on the effective thermal conductivity of liquid helium II in cylindrical channels to rectangular channels with high aspect ratio. The aim is to compare the results in the laminar regime, the turbulent regime and the ballistic regime, all of them obtained within a single mesoscopic formalism of heat transport, with heat flux as an independent variable.

Measurements and Experimental Database Review for Laminar Flame Speed Premixed Ch4/Air Flames

Science.gov (United States)

Zubrilin, I. A.; Matveev, S. S.; Matveev, S. G.; Idrisov, D. V.

2018-01-01

Laminar flame speed (SL ) of CH4 was determined at atmospheric pressure and initial gas temperatures in range from 298 to 358 K. The heat flux method was employed to measure the flame speed in non-stretched flames. The kinetic mechanism GRI 3.0 [1] were used to simulate SL . The measurements were compared with available literature results. The data determined with the heat flux method agree with some previous burner measurements and disagree with the data from some vessel closed method and counterflow method. The GRI 3.0 mechanism was able to reproduce the present experiments. Laminar flame speed was determined at pressures range from of 1 to 20 atmospheres through mechanism GRI 3.0. Based on experimental data and calculations was obtained SL dependence on pressure and temperature. The resulting of dependence recommended use during the numerical simulation of methane combustion.

New method for the determination of precipitation kinetics using a laminar jet reactor

NARCIS (Netherlands)

Al Tarazi, M.Y.M.; Heesink, Albertus B.M.; Versteeg, Geert

2005-01-01

In this paper a new experimental method for determining the kinetics of fast precipitation reactions is introduced. Use is made of a laminar jet reactor, which is also frequently applied to determine the kinetics of homogeneous gas–liquid reactions. The liquid containing one or more of the

New method for the determination of precipitation kinetics using a laminar jet reactor

NARCIS (Netherlands)

Al-Tarazi, Mousa; Heesink, A. Bert M.; Versteeg, Geert F.

2005-01-01

In this paper a new experimental method for determining the kinetics of fast precipitation reactions is introduced. Use is made of a laminar jet reactor, which is also frequently applied to determine the kinetics of homogeneous gas-liquid reactions. The liquid containing one or more of the

Laminar phase flow for an exponentially tapered Josephson oscillator

DEFF Research Database (Denmark)

Benabdallah, A.; Caputo, J. G.; Scott, Alwyn C.

2000-01-01

Exponential tapering and inhomogeneous current feed were recently proposed as means to improve the performance of a Josephson flux flow oscillator. Extensive numerical results backed up by analysis are presented here that support this claim and demonstrate that exponential tapering reduces...... the small current instability region and leads to a laminar flow regime where the voltage wave form is periodic giving the oscillator minimal spectral width. Tapering also leads to an increased output power. Since exponential tapering is not expected to increase the difficulty of fabricating a flux flow...

Transient convective heat transfer to laminar flow from a flat plate with constant heat capacity

International Nuclear Information System (INIS)

Hanawa, Juichi

1980-01-01

Most basic transient heat transfer problem is the transient response characteristics of forced convection heat transfer in the flow along a flat plate or in a tube. In case of the laminar flow along a flat plate, the profile method using steady temperature distribution has been mostly adopted, but its propriety has not been clarified yet. About the unsteady heat transfer in the laminar flow along a flat plate, the analysis or experiment evaluating the heat capacity of the flat plate exactly was never carried out. The purpose of this study is to determine by numerical calculation the unsteady characteristics of the boundary layer in laminar flow and to confirm them by experiment concerning the unsteady heat transfer when a flat plate with a certain heat capacity is placed in parallel in uniform flow and given a certain quantity of heat generation suddenly. The basic equation and the solution are given, and the method of numerical calculation and the result are explained. The experimental setup and method, and the experimental results are shown. Both results were in good agreement, and the response of wall temperature, the response of Nusselt number and the change of temperature distribution in course of time were able to be determined by applying Laplace transformation and numerical Laplace inverse transformation to the equation. (Kako, I.)

An experimental investigation of laminar free convection from a vertical flat plate at general boundary condition

International Nuclear Information System (INIS)

Aharon, J.; Lahav, C.; Kalman, H.; Shai, I.

1996-01-01

The present work deals with natural convection on a vertical flat plate, where one side of the plate is exposed to an environment of constant temperature - T a , with which heat is exchanged at an effective heat transfer coefficient, Glen. The other side of the plate is exposed to a fluid at a different temperature -T ∞ . The temperature gradient induces a natural convection in the fluid. The present investigation treats the heat transfer problem in the laminar cone in air (P r =1). An experimental apparatus has been constructed to confirm the heat transfer features predicted analytically in previous work. The local experimental Nusselt number was correlated with the modified Rayleigh number, for the laminar range. (authors)

LAMINAR FLOW THROUGH A TUBE WITH AN EASILY PENETRABLE ROUGHNESS NEAR AXIS

Directory of Open Access Journals (Sweden)

Є.О. Гаєв

2012-12-01

Full Text Available  Mathematical model has been suggested and investigation carried out of laminar flow through a round tube with a porous insertion (easily penetrable roughness, EPR in its middle along the axis. Velocity and shear fields have been found analytically for stable flow region, as well as hydraulic resistance as functions of EPR density and its height.

Laminar differences in response to simple and spectro-temporally complex sounds in the primary auditory cortex of ketamine-anesthetized gerbils.

Directory of Open Access Journals (Sweden)

Markus K Schaefer

Full Text Available In mammals, acoustic communication plays an important role during social behaviors. Despite their ethological relevance, the mechanisms by which the auditory cortex represents different communication call properties remain elusive. Recent studies have pointed out that communication-sound encoding could be based on discharge patterns of neuronal populations. Following this idea, we investigated whether the activity of local neuronal networks, such as those occurring within individual cortical columns, is sufficient for distinguishing between sounds that differed in their spectro-temporal properties. To accomplish this aim, we analyzed simple pure-tone and complex communication call elicited multi-unit activity (MUA as well as local field potentials (LFP, and current source density (CSD waveforms at the single-layer and columnar level from the primary auditory cortex of anesthetized Mongolian gerbils. Multi-dimensional scaling analysis was used to evaluate the degree of "call-specificity" in the evoked activity. The results showed that whole laminar profiles segregated 1.8-2.6 times better across calls than single-layer activity. Also, laminar LFP and CSD profiles segregated better than MUA profiles. Significant differences between CSD profiles evoked by different sounds were more pronounced at mid and late latencies in the granular and infragranular layers and these differences were based on the absence and/or presence of current sinks and on sink timing. The stimulus-specific activity patterns observed within cortical columns suggests that the joint activity of local cortical populations (as local as single columns could indeed be important for encoding sounds that differ in their acoustic attributes.

The construction of a laminar-flow cell for neutron reflection studies

International Nuclear Information System (INIS)

Haemers, S.; Efimova, Y.M.; Well, A.A. van

2005-01-01

The characteristic time scale of adsorption has an important contribution to the history of adsorbed protein layers. Control over this time scale is achieved by designing a measuring cell with well-defined laminar liquid flow in parallel plate geometry to be used on a neutron reflectometer. Results obtained from adsorption experiments with lysozyme clearly show that there is an effect of adsorption time scales on the properties of adsorbed layers

Utilization of Ancillary Data Sets for Conceptual SMAP Mission Algorithm Development and Product Generation

Science.gov (United States)

O'Neill, P.; Podest, E.

2011-01-01

The planned Soil Moisture Active Passive (SMAP) mission is one of the first Earth observation satellites being developed by NASA in response to the National Research Council's Decadal Survey, Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond [1]. Scheduled to launch late in 2014, the proposed SMAP mission would provide high resolution and frequent revisit global mapping of soil moisture and freeze/thaw state, utilizing enhanced Radio Frequency Interference (RFI) mitigation approaches to collect new measurements of the hydrological condition of the Earth's surface. The SMAP instrument design incorporates an L-band radar (3 km) and an L band radiometer (40 km) sharing a single 6-meter rotating mesh antenna to provide measurements of soil moisture and landscape freeze/thaw state [2]. These observations would (1) improve our understanding of linkages between the Earth's water, energy, and carbon cycles, (2) benefit many application areas including numerical weather and climate prediction, flood and drought monitoring, agricultural productivity, human health, and national security, (3) help to address priority questions on climate change, and (4) potentially provide continuity with brightness temperature and soil moisture measurements from ESA's SMOS (Soil Moisture Ocean Salinity) and NASA's Aquarius missions. In the planned SMAP mission prelaunch time frame, baseline algorithms are being developed for generating (1) soil moisture products both from radiometer measurements on a 36 km grid and from combined radar/radiometer measurements on a 9 km grid, and (2) freeze/thaw products from radar measurements on a 3 km grid. These retrieval algorithms need a variety of global ancillary data, both static and dynamic, to run the retrieval models, constrain the retrievals, and provide flags for indicating retrieval quality. The choice of which ancillary dataset to use for a particular SMAP product would be based on a number of factors

A Three-Part Electricity Price Mechanism for Photovoltaic-Battery Energy Storage Power Plants Considering the Power Quality and Ancillary Service

Directory of Open Access Journals (Sweden)

Yajing Gao

2017-08-01

Full Text Available To solve the problem of solar abandoning, which is accompanied by the rapid development of photovoltaic (PV power generation, a demonstration of a photovoltaic-battery energy storage system (PV-BESS power plant has been constructed in Qinghai province in China. However, it is difficult for the PV-BESS power plant to survive and develop with the current electricity price mechanism and subsidy policy. In this paper, a three-part electricity price mechanism is proposed based on a deep analysis of the construction and operation costs and economic income. The on-grid electricity price is divided into three parts: the capacity price, graded electricity price, and ancillary service price. First, to ensure that the investment of the PV-BESS power plant would achieve the industry benchmark income, the capacity price and benchmark electricity price are calculated using the discounted cash flow method. Then, the graded electricity price is calculated according to the grade of the quality of grid-connected power. Finally, the ancillary service price is calculated based on the graded electricity price and ancillary service compensation. The case studies verify the validity of the three-part electricity price mechanism. The verification shows that the three-part electricity price mechanism can help PV-BESS power plants to obtain good economic returns, which can promote the development of PV-BESS power plants.

Analysis of the flamelet concept in the numerical simulation of laminar partially premixed flames

Energy Technology Data Exchange (ETDEWEB)

Consul, R.; Oliva, A.; Perez-Segarra, C.D.; Carbonell, D. [Centre Tecnologic de Transferencia de Calor (CTTC), Universitat Politecnica de Catalunya (UPC), Colom 11, E-08222, Terrassa, Barcelona (Spain); de Goey, L.P.H. [Eindhoven University of Technology, Department of Mechanical Engineering, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

2008-04-15

The aim of this work is to analyze the application of flamelet models based on the mixture fraction variable and its dissipation rate to the numerical simulation of partially premixed flames. Although the main application of these models is the computation of turbulent flames, this work focuses on the performance of flamelet concept in laminar flame simulations removing, in this way, turbulence closure interactions. A well-known coflow methane/air laminar flame is selected. Five levels of premixing are taken into account from an equivalence ratio {phi}={infinity} (nonpremixed) to {phi}=2.464. Results obtained using the flamelet approaches are compared to data obtained from the detailed solution of the complete transport equations using primitive variables. Numerical simulations of a counterflow flame are also presented to support the discussion of the results. Special emphasis is given to the analysis of the scalar dissipation rate modeling. (author)

Electric fields effect on liftoff and blowoff of nonpremixed laminar jet flames in a coflow

KAUST Repository

Kim, Minkuk; Ryu, Seol; Won, Sanghee; Chung, Suk-Ho

2010-01-01

The stabilization characteristics of liftoff and blowoff in nonpremixed laminar jet flames in a coflow have been investigated experimentally for propane fuel by applying AC and DC electric fields to the fuel nozzle with a single

A short remark on Stewart 1962 variational principle for laminar flow in a uniform duct

Directory of Open Access Journals (Sweden)

Liu Hong-Yan

2016-01-01

Full Text Available This paper concludes that Stewart 1962 variational principle for laminar flow in a uniform duct is for a differential-difference. Some generalized variational principles are elucidated with or without Stewart’s discrete treatment.

Determination of the critical Shields number for particle erosion in laminar flow

OpenAIRE

Ouriemi , Malika; Aussillous , Pascale; Medale , Marc; Peysson , Yannick; Guazzelli , Élisabeth

2007-01-01

International audience; We present reproducible experimental measurements for the onset of grain motion in laminar flow and find a constant critical Shields number for particle erosion, i.e., c = 0.12± 0.03, over a large range of small particle Reynolds number: 1.5 10 −5 Re p 0.76. Comparison with previous studies found in the literature is provided.

Surgical clothing systems in laminar airflow operating room: a numerical assessment.

Science.gov (United States)

Sadrizadeh, Sasan; Holmberg, Sture

2014-01-01

This study compared two different laminar airflow distribution strategies - horizontal and vertical - and investigated the effectiveness of both ventilation systems in terms of reducing the sedimentation and distribution of bacteria-carrying particles. Three different staff clothing systems, which resulted in source strengths of 1.5, 4 and 5 CFU/s per person, were considered. The exploration was conducted numerically using a computational fluid dynamics technique. Active and passive air sampling methods were simulated in addition to recovery tests, and the results were compared. Model validation was performed through comparisons with measurement data from the published literature. The recovery test yielded a value of 8.1 min for the horizontal ventilation scenario and 11.9 min for the vertical ventilation system. Fewer particles were captured by the slit sampler and in sedimentation areas with the horizontal ventilation system. The simulated results revealed that under identical conditions in the examined operating room, the horizontal laminar ventilation system performed better than the vertical option. The internal constellation of lamps, the surgical team and objects could have a serious effect on the movement of infectious particles and therefore on postoperative surgical site infections. Copyright © 2014 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

Prevention of airborne contamination and cross-contamination in germ-free mice by laminar flow

NARCIS (Netherlands)

Waaij, D. van der; Andres, A.H.

1971-01-01

The efficacy of horizontal and vertical laminar flow units (equipped with high-efficiency air filters) in the prevention of cross-contamination between cages and of contamination from outside has been demonstrated. With germ-free mice and using germ-free standard techniques for sterilization and for

Planck intermediate results XXIII. Galactic plane emission components derived from Planck with ancillary data

DEFF Research Database (Denmark)

Ade, P. A. R.; Aghanim, N.; Arnaud, M.

2015-01-01

Planck data when combined with ancillary data provide a unique opportunity to separate the diuse emission components of the inner Galaxy.The purpose of the paper is to elucidate the morphology of the various emission components in the strong star-formation region lying inside thesolar radius and ...

Sensitivity analysis of time-dependent laminar flows

International Nuclear Information System (INIS)

Hristova, H.; Etienne, S.; Pelletier, D.; Borggaard, J.

2004-01-01

This paper presents a general sensitivity equation method (SEM) for time dependent incompressible laminar flows. The SEM accounts for complex parameter dependence and is suitable for a wide range of problems. The formulation is verified on a problem with a closed form solution obtained by the method of manufactured solution. Systematic grid convergence studies confirm the theoretical rates of convergence in both space and time. The methodology is then applied to pulsatile flow around a square cylinder. Computations show that the flow starts with symmetrical vortex shedding followed by a transition to the traditional Von Karman street (alternate vortex shedding). Simulations show that the transition phase manifests itself earlier in the sensitivity fields than in the flow field itself. Sensitivities are then demonstrated for fast evaluation of nearby flows and uncertainty analysis. (author)

A uniform laminar air plasma plume with large volume excited by an alternating current voltage

Science.gov (United States)

Li, Xuechen; Bao, Wenting; Chu, Jingdi; Zhang, Panpan; Jia, Pengying

2015-12-01

Using a plasma jet composed of two needle electrodes, a laminar plasma plume with large volume is generated in air through an alternating current voltage excitation. Based on high-speed photography, a train of filaments is observed to propagate periodically away from their birth place along the gas flow. The laminar plume is in fact a temporal superposition of the arched filament train. The filament consists of a negative glow near the real time cathode, a positive column near the real time anode, and a Faraday dark space between them. It has been found that the propagation velocity of the filament increases with increasing the gas flow rate. Furthermore, the filament lifetime tends to follow a normal distribution (Gaussian distribution). The most probable lifetime decreases with increasing the gas flow rate or decreasing the averaged peak voltage. Results also indicate that the real time peak current decreases and the real time peak voltage increases with the propagation of the filament along the gas flow. The voltage-current curve indicates that, in every discharge cycle, the filament evolves from a Townsend discharge to a glow one and then the discharge quenches. Characteristic regions including a negative glow, a Faraday dark space, and a positive column can be discerned from the discharge filament. Furthermore, the plasma parameters such as the electron density, the vibrational temperature and the gas temperature are investigated based on the optical spectrum emitted from the laminar plume.

A numerical investigation of laminar forced convection in a solar collector with non-circular duct

Directory of Open Access Journals (Sweden)

Teleszewski Tomasz Janusz

2017-01-01

Full Text Available This paper presents a two-dimensional numerical study to investigate laminar flow in a flat plate solar collector with non-circular duct (regular polygonal, elliptical, and Cassini oval shape featuring forced convection with constant axial wall heat flux and constant peripheral wall temperature (H1 condition. Applying the velocity profile obtained for the duct laminar flow, the energy equation was solved exactly for the constant wall heat flux using the Boundary Element Method (BEM. Poiseuille and Nusselt numbers were obtained for flows having a different number of geometrical factors. The results are presented and discussed in the form of tables and graphs. The area goodness factor and volume goodness factor are calculated. The predicted correlations for Poiseuille and Nusselt numbers may be a very useful resource for the design and optimization of solar collectors with non-circular ducts.

Investigation on the properties of a laminar grating as a soft x-ray beam splitter

International Nuclear Information System (INIS)

Liu Ying; Fuchs, Hans-Joerg; Liu Zhengkun; Chen Huoyao; He Shengnan; Fu Shaojun; Kley, Ernst-Bernhard; Tuennermann, Andreas

2010-01-01

Laminar-type gratings as soft x-ray beam splitters for interferometry are presented. Gold-coated grating beam splitters with 1000 lines/mm are designed for grazing incidence operation at 13.9nm. They are routinely fabricated using electron beam lithography and ion etching techniques. The laminar grating is measured to have almost equal absolute efficiencies of about 20% in the zeroth and -1st orders, which enables a fringe visibility up to 0.99 in the interferometer. The discrepancy of the grating profiles between the optimized theoretical and the experimental results is analyzed according to the comparison of the optimized simulation results and the measurement realization of the grating efficiencies. By a precise control of the grating profile, the grating efficiency in the -1st order and the fringe visibility could be improved to 25% and 1, respectively.

A numerical investigation of laminar forced convection in a solar collector with non-circular duct

Science.gov (United States)

Janusz Teleszewski, Tomasz

2017-11-01

This paper presents a two-dimensional numerical study to investigate laminar flow in a flat plate solar collector with non-circular duct (regular polygonal, elliptical, and Cassini oval shape) featuring forced convection with constant axial wall heat flux and constant peripheral wall temperature (H1 condition). Applying the velocity profile obtained for the duct laminar flow, the energy equation was solved exactly for the constant wall heat flux using the Boundary Element Method (BEM). Poiseuille and Nusselt numbers were obtained for flows having a different number of geometrical factors. The results are presented and discussed in the form of tables and graphs. The area goodness factor and volume goodness factor are calculated. The predicted correlations for Poiseuille and Nusselt numbers may be a very useful resource for the design and optimization of solar collectors with non-circular ducts.

DRAG REDUCTION IN LAMINAR FLOW BY LUBRICATION OF GROOVED WALLS

OpenAIRE

JULIO RAUL SIERRA VASQUEZ

2009-01-01

Objetivo: Uma parte significativa das reservas mundiais de petróleo é encontrada na forma de óleos pesados. Estes óleos pesados possuem alta viscosidade de 100 - 10000 cP, que torna seu transporte altamente complexo e custoso. Vários métodos foram desenvolvidos para reduzir a perda de carga de escoamentos laminares de óleos de alta viscosidade. Entre os mais utilizados, pode-se citar o bombeio de um fluido de baixa viscosidade perto da parede do tubo com o óleo viscoso sendo...

Laminar flow resistance in short microtubes

Energy Technology Data Exchange (ETDEWEB)

Phares, D.J. [Texas A and M University, College Station, TX (United States). Dept. of Mechanical Engineering; Smedley, G.T.; Zhou, J. [Glaukos Corp., Laguna Hills, CA (United States). Dept. of Research and Development

2005-06-01

We have measured the pressure drop for the flow of liquid through a series of short microtubes ranging from 80 to 150 {mu}m in diameter with aspect ratios between L/D = 2 and L/D = 5. These dimensions were selected to resemble lumens of implantable microstents that are under consideration for the treatment of glaucoma. For physiologically relevant pressure drops and flow rates, we have determined that a fully-developed laminar pipe flow may be assumed throughout the microtube when (L/D) > 0.20Re, where Re is the Reynolds number based on the diameter, D, and L is the length of the tube. We have examined flow rates between 0.1 and 10 {mu}L/s, corresponding to Reynolds numbers between 1 and 150. For smooth microtubes, no difference from macroscopic flow is observed for the tube sizes considered. However, flow resistance is found to be sensitive to the relative surface roughness of the tube walls. (author)

Laminar nanofluid flow in microheat-sinks

Energy Technology Data Exchange (ETDEWEB)

Koo, J.; Kleinstreuer, C. [North Carolina State University, Raleigh, NC (United States). Dept. of Mechanical and Aerospace Engineering

2005-06-01

In response to the ever increasing demand for smaller and lighter high-performance cooling devices, steady laminar liquid nanofluid flow in microchannels is simulated and analyzed. Considering two types of nanofluids, i.e., copper-oxide nanospheres at low volume concentrations in water or ethylene glycol, the conjugated heat transfer problem for microheat-sinks has been numerically solved. Employing new models for the effective thermal conductivity and dynamic viscosity of nanofluids, the impact of nanoparticle concentrations in these two mixture flows on the microchannel pressure gradients, temperature profiles and Nusselt numbers are computed, in light of aspect ratio, viscous dissipation, and enhanced temperature effects. Based on these results, the following can be recommended for microheat-sink performance improvements: Use of large high-Prandtl number carrier fluids, nanoparticles at high volume concentrations of about 4% with elevated thermal conductivities and dielectric constants very close to that of the carrier fluid, microchannels with high aspect ratios, and treated channel walls to avoid nanoparticle accumulation. (Author)

Steady laminar flow of fractal fluids

Energy Technology Data Exchange (ETDEWEB)

Balankin, Alexander S., E-mail: abalankin@ipn.mx [Grupo Mecánica Fractal, ESIME, Instituto Politécnico Nacional, México D.F., 07738 (Mexico); Mena, Baltasar [Laboratorio de Ingeniería y Procesos Costeros, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Sisal, Yucatán, 97355 (Mexico); Susarrey, Orlando; Samayoa, Didier [Grupo Mecánica Fractal, ESIME, Instituto Politécnico Nacional, México D.F., 07738 (Mexico)

2017-02-12

We study laminar flow of a fractal fluid in a cylindrical tube. A flow of the fractal fluid is mapped into a homogeneous flow in a fractional dimensional space with metric induced by the fractal topology. The equations of motion for an incompressible Stokes flow of the Newtonian fractal fluid are derived. It is found that the radial distribution for the velocity in a steady Poiseuille flow of a fractal fluid is governed by the fractal metric of the flow, whereas the pressure distribution along the flow direction depends on the fractal topology of flow, as well as on the fractal metric. The radial distribution of the fractal fluid velocity in a steady Couette flow between two concentric cylinders is also derived. - Highlights: • Equations of Stokes flow of Newtonian fractal fluid are derived. • Pressure distribution in the Newtonian fractal fluid is derived. • Velocity distribution in Poiseuille flow of fractal fluid is found. • Velocity distribution in a steady Couette flow is established.

Subcortical laminar heterotopia in two sisters and their mother : MRI, clinical findings and pathogenesis

NARCIS (Netherlands)

van der Valk, PHM; Snoeck, [No Value; Meiners, LC; des Portes, [No Value; Chelly, J; Pinard, JM; Ippel, PF; van Nieuwenhuizen, O

MR imaging, clinical data and underlying pathogenesis of subcortical laminar heterotopia (SCLH), also known as band heterotopia, in two sisters and their mother are presented. On MR imaging a different degree of SCLH was found in all three affected family-members. The inversion recovery sequence was

A Laminar Flow-Based Microfluidic Tesla Pump via Lithography Enabled 3D Printing

Directory of Open Access Journals (Sweden)

Mohammed-Baker Habhab

2016-11-01

Full Text Available Tesla turbine and its applications in power generation and fluid flow were demonstrated by Nicholas Tesla in 1913. However, its real-world implementations were limited by the difficulty to maintain laminar flow between rotor disks, transient efficiencies during rotor acceleration, and the lack of other applications that fully utilize the continuous flow outputs. All of the aforementioned limits of Tesla turbines can be addressed by scaling to the microfluidic flow regime. Demonstrated here is a microscale Tesla pump designed and fabricated using a Digital Light Processing (DLP based 3D printer with 43 µm lateral and 30 µm thickness resolutions. The miniaturized pump is characterized by low Reynolds number of 1000 and a flow rate of up to 12.6 mL/min at 1200 rpm, unloaded. It is capable of driving a mixer network to generate microfluidic gradient. The continuous, laminar flow from Tesla turbines is well-suited to the needs of flow-sensitive microfluidics, where the integrated pump will enable numerous compact lab-on-a-chip applications.

Buoyancy effects laminar slot jet impinging on a surface with constant heat flux

International Nuclear Information System (INIS)

Shokouhmand, H.; Esfahanian, V.; Masoodi, R.

2004-01-01

The two-dimensional laminar air jet issuing from a nozzle of half which terminates at height above a flat plate normal to the jet is numerically on the flow and thermal structure of the region near impingement. The impinging surface is maintained at a constant heat flux condition. The full Navier-Stocks and energy equations are solved by a finite difference method to evaluate the velocity profiles and temperature distribution. The governing parameters and their ranges are: Reynolds number Re, 10-50, Grashof number Gr, 0-50, Richardson number Ri=Gr/ Re 2 , Non dimensional nozzle height H,2-3. Results of the free streamline, local friction factor and heat transfer coefficient are graphically presented. It is found that enhancement of the heat transfer rate is substantial for high Richardson number conditions. Although the laminar jet impingement for isothermal condition has been already studied, however the constant heat flux has not been studied enough. the present paper will analyze a low velocity air jet, Which can be used for cooling of a simulated electronics package

Calculation of laminar incompressible fluid flow and heat transfer during spherical annulus filling

International Nuclear Information System (INIS)

Tuft, D.B.

1979-04-01

A method of computing laminar incompressible fluid-flow and heat transfer during the filling of a spherical annulus is presented. Transient fluid temperatures and heat flux rates in the spherical annulus are calculated for an insulated outer sphere and a constant temperature inner sphere with heated water filling the annulus from the bottom. To achieve a solution, laminar axially symmetric flow is assumed and the Marker-and-Cell (MAC) free surface computational method is applied to this problem in spherical coordinates. Changes in the standard MAC treatment are incorporated and special methods for handling the free surface are introduced. A variable mesh is used to improve resolution near the inner sphere where temperature and velocity gradients are steep and the governing equations are derived for variable fluid properties to allow an eddy viscosity turbulence model to be applied later. Calculations of velocity, temperature, and inner sphere heat flux in a spherical annulus of 139.7 mm inner radius, and 168.3 mm outer radius within an inlet tube diameter of 38.1 mm are presented

In situ analysis of dynamic laminar flow extraction using surface-enhanced Raman spectroscopy

Science.gov (United States)

Wang, Fei; Wang, Hua-Lin; Qiu, Yang; Chang, Yu-Long; Long, Yi-Tao

2015-12-01

In this study, we performed micro-scale dynamic laminar flow extraction and site-specific in situ chloride concentration measurements. Surface-enhanced Raman spectroscopy was utilized to investigate the diffusion process of chloride ions from an oil phase to a water phase under laminar flow. In contrast to common logic, we used SERS intensity gradients of Rhodamine 6G to quantitatively calculate the concentration of chloride ions at specific positions on a microfluidic chip. By varying the fluid flow rates, we achieved different extraction times and therefore different chloride concentrations at specific positions along the microchannel. SERS spectra from the water phase were recorded at these different positions, and the spatial distribution of the SERS signals was used to map the degree of nanoparticle aggregation. The concentration of chloride ions in the channel could therefore be obtained. We conclude that this method can be used to explore the extraction behaviour and efficiency of some ions or molecules that enhance the SERS intensity in water or oil by inducing nanoparticle aggregation.

A Laminar Flow-Based Microfluidic Tesla Pump via Lithography Enabled 3D Printing.

Science.gov (United States)

Habhab, Mohammed-Baker; Ismail, Tania; Lo, Joe Fujiou

2016-11-23

Tesla turbine and its applications in power generation and fluid flow were demonstrated by Nicholas Tesla in 1913. However, its real-world implementations were limited by the difficulty to maintain laminar flow between rotor disks, transient efficiencies during rotor acceleration, and the lack of other applications that fully utilize the continuous flow outputs. All of the aforementioned limits of Tesla turbines can be addressed by scaling to the microfluidic flow regime. Demonstrated here is a microscale Tesla pump designed and fabricated using a Digital Light Processing (DLP) based 3D printer with 43 µm lateral and 30 µm thickness resolutions. The miniaturized pump is characterized by low Reynolds number of 1000 and a flow rate of up to 12.6 mL/min at 1200 rpm, unloaded. It is capable of driving a mixer network to generate microfluidic gradient. The continuous, laminar flow from Tesla turbines is well-suited to the needs of flow-sensitive microfluidics, where the integrated pump will enable numerous compact lab-on-a-chip applications.

Laminar and Temporal Expression Dynamics of Coding and Noncoding RNAs in the Mouse Neocortex

Directory of Open Access Journals (Sweden)

Sofia Fertuzinhos

2014-03-01

Full Text Available The hallmark of the cerebral neocortex is its organization into six layers, each containing a characteristic set of cell types and synaptic connections. The transcriptional events involved in laminar development and function still remain elusive. Here, we employed deep sequencing of mRNA and small RNA species to gain insights into transcriptional differences among layers and their temporal dynamics during postnatal development of the mouse primary somatosensory neocortex. We identify a number of coding and noncoding transcripts with specific spatiotemporal expression and splicing patterns. We also identify signature trajectories and gene coexpression networks associated with distinct biological processes and transcriptional overlap between these processes. Finally, we provide data that allow the study of potential miRNA and mRNA interactions. Overall, this study provides an integrated view of the laminar and temporal expression dynamics of coding and noncoding transcripts in the mouse neocortex and a resource for studies of neurodevelopment and transcriptome.

Propagation of atmospheric pressure helium plasma jet into ambient air at laminar gas flow

Science.gov (United States)

Pinchuk, M.; Stepanova, O.; Kurakina, N.; Spodobin, V.

2017-05-01

The formation of an atmospheric pressure plasma jet (APPJ) in a gas flow passing through the discharge gap depends on both gas-dynamic properties and electrophysical parameters of the plasma jet generator. The paper presents the results of experimental and numerical study of the propagation of the APPJ in a laminar flow of helium. A dielectric-barrier discharge (DBD) generated inside a quartz tube equipped with a coaxial electrode system, which provided gas passing through it, served as a plasma source. The transition of the laminar regime of gas flow into turbulent one was controlled by the photography of a formed plasma jet. The corresponding gas outlet velocity and Reynolds numbers were revealed experimentally and were used to simulate gas dynamics with OpenFOAM software. The data of the numerical simulation suggest that the length of plasma jet at the unvarying electrophysical parameters of DBD strongly depends on the mole fraction of ambient air in a helium flow, which is established along the direction of gas flow.

Analytic solutions to linear, time-dependent fission product deposition models for isothermal laminar, slug, or multiregion flow conditions

International Nuclear Information System (INIS)

Durkee, J.W. Jr.

1983-01-01

The time-dependent convective-diffusion equation with radioactive decay is solved analytically in axisymmetric cylindrical geometry for laminar and slug velocity profiles under isothermal conditions. Concentration dependent diffusion is neglected. The laminar flow solution is derived using the method of separation of variables and Frobenius' technique for constructing a series expansion about a regular singular point. The slug flow multiregion solution is obtained using the method of separation of variables. The Davidon Variable Metric Minimization algorithm is used to compute the coupling coefficients. These solutions, which describe the transport of fission products in a flowing stream, are then used to determine the concentration of radioactive material deposited on a conduit wall using a standard mass transfer model. Fission product deposition measurements for five diffusion tubes in a Fort St. Vrain High-Temperature Gas-Cooled reactor plateout probe are analyzed. Using single region slug and laminar models, the wall mass transfer coefficients, diffusion coefficients, and inlet concentrations are determined using least squares analysis. The diffusion coefficients and inlet concentrations are consistent between tubes. The derived diffusion coefficients and wall mass transfer coefficients are in relative agreement with known literature values

International Society of Gynecological Pathologists (ISGyP) Endometrial Cancer Project: Guidelines From the Special Techniques and Ancillary Studies Group.

Science.gov (United States)

Cho, Kathleen R; Cooper, Kumarasen; Croce, Sabrina; Djordevic, Bojana; Herrington, Simon; Howitt, Brooke; Hui, Pei; Ip, Philip; Koebel, Martin; Lax, Sigurd; Quade, Bradley J; Shaw, Patricia; Vidal, August; Yemelyanova, Anna; Clarke, Blaise; Hedrick Ellenson, Lora; Longacre, Teri A; Shih, Ie-Ming; McCluggage, W Glenn; Malpica, Anais; Oliva, Esther; Parkash, Vinita; Matias-Guiu, Xavier

2018-04-11

The aim of this article is to propose guidelines and recommendations in problematic areas in pathologic reporting of endometrial carcinoma (EC) regarding special techniques and ancillary studies. An organizing committee designed a comprehensive survey with different questions related to pathologic features, diagnosis, and prognosis of EC that was sent to all members of the International Society of Gynecological Pathologists. The special techniques/ancillary studies group received 4 different questions to be addressed. Five members of the group reviewed the literature and came up with recommendations and an accompanying text which were discussed and agreed upon by all members of the group. Twelve different recommendations are made. They address the value of immunohistochemistry, ploidy, and molecular analysis for assessing prognosis in EC, the value of steroid hormone receptor analysis to predict response to hormone therapy, and parameters regarding applying immunohistochemistry and molecular tests for assessing mismatch deficiency in EC.

Simulations and experiments of laminar heat transfer for Therminol heat transfer fluids in a rifled tube

International Nuclear Information System (INIS)

Xu, Weiguo; Ren, Depeng; Ye, Qing; Liu, Guodong; Lu, Huilin; Wang, Shuai

2016-01-01

Graphical abstract: Predicted laminar Nusselt number using regression correlation of Therminol-55 heat transfer fluid is in agreement with experiments in the rifled tube. - Highlights: • Heat transfer coefficient and friction factor are measured and predicted in the rifled tube. • Correlations for Nusselt number and friction factor are proposed. • The roughness height of 0.425 mm in transition SST model is suggested as an input parameter. • k–kl–ω transition and transition SST models are recommended for laminar–turbulent transition. • Thermal enhancement factor and synergy angle are predicted in the rifled tube. - Abstract: Simulations and experiments of flow and heat transfer behavior of Therminol-55 heat transfer fluid have been conducted in a horizontal rifled tube with outer diameter and inner diameter 25.0 and 20.0 mm, pitch and rib height of 12.0 and 1.0 mm, respectively. Numerical simulations of three-dimensional flow behavior of Therminol-55 heat transfer fluid are carried out using FLUENT code in the rifled tube. Experimental results show that the heat transfer and thermal performance of Therminol-55 heat transfer fluid in the rifled tube are considerably improved compared to those of the smooth tube. The Nusselt number increases with the increase of Reynolds number, and is from 3.5 to 5.1 times over the smooth tube. Also, the pressure drop results reveal that the average friction factor of the ribbed tube is in a range of 2.2 and 4.2 times over the smooth tube. Predictive Nusselt number and friction factor correlations have been presented. The numerical results show that the laminar flow model is valid only at lower Reynolds number in the developed laminar flow of rifled tube. The k–kl–ω transition model and transition SST model with roughness of 0.425 mm are recommended for the predictions of transition process from laminar to turbulent flow in the rifled tube.

Island operation capability in the Colombian electrical market: a promising ancillary service of distributed energy resources

DEFF Research Database (Denmark)

Marín-Jiménez, Juan D.; Carvajal-Quintero, Sandra; Guerrero, Josep M.

2018-01-01

is presented. Subsequently, an existing electrical distribution system with small hydropower plants is considered as a study case in order to identify the technical requirements set out for both, the distribution system and the generation source. Finally, taking into account the current Law and regulations......, a proposal is outlined for the implementation of the island operation capability ancillary service in the Colombian electrical system....

Effect of laminar airflow ventilation on surgical site infections: a systematic review and meta-analysis.

Science.gov (United States)

Bischoff, Peter; Kubilay, N Zeynep; Allegranzi, Benedetta; Egger, Matthias; Gastmeier, Petra

2017-05-01

The role of the operating room's ventilation system in the prevention of surgical site infections (SSIs) is widely discussed, and existing guidelines do not reflect current evidence. In this context, laminar airflow ventilation was compared with conventional ventilation to assess their effectiveness in reducing the risk of SSIs. We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and WHO regional medical databases from Jan 1, 1990, to Jan 31, 2014. We updated the search for MEDLINE for the period between Feb 1, 2014, and May 25, 2016. We included studies most relevant to our predefined question: is the use of laminar airflow in the operating room associated with the reduction of overall or deep SSI as outcomes in patients of any age undergoing surgical operations? We excluded studies not relevant to the study question, studies not in the selected languages, studies published before Jan 1, 1990, or after May 25, 2016, meeting or conference abstracts, and studies of which the full text was not available. Data were extracted by two independent investigators, with disagreements resolved through further discussion. Authors were contacted if the full-text article was not available, or if important data or information on the paper's content was absent. Studies were assessed for publication bias. Grading of recommendations assessment, development, and evaluation was used to assess the quality of the identified evidence. Meta-analyses were done with RevMan (version 5.3). We identified 1947 records of which 12 observational studies were comparing laminar airflow ventilation with conventional turbulent ventilation in orthopaedic, abdominal, and vascular surgery. The meta-analysis of eight cohort studies showed no difference in risk for deep SSIs following total hip arthroplasty (330 146 procedures, odds ratio [OR] 1·29, 95% CI 0·98-1·71; p=0·07, I 2 =83%). For total knee arthroplasty, the meta-analysis of six cohort studies showed no difference

Energy and ancillary service dispatch through dynamic optimal power flow

International Nuclear Information System (INIS)

Costa, A.L.; Costa, A. Simoes

2007-01-01

This paper presents an approach based on dynamic optimal power flow (DOPF) to clear both energy and spinning reserve day-ahead markets. A competitive environment is assumed, where agents can offer active power for both demand supply and ancillary services. The DOPF jointly determines the optimal solutions for both energy dispatch and reserve allocation. A non-linear representation for the electrical network is employed, which is able to take transmission losses and power flow limits into account. An attractive feature of the proposed approach is that the final optimal solution will automatically meet physical constraints such as generating limits and ramp rate restrictions. In addition, the proposed framework allows the definition of multiple zones in the network for each time interval, in order to ensure a more adequate distribution of reserves throughout the power system. (author)

47 CFR 25.254 - Special requirements for ancillary terrestrial components operating in the 1610-1626.5 MHz/2483.5...

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Special requirements for ancillary terrestrial components operating in the 1610-1626.5 MHz/2483.5-2500 MHz bands. 25.254 Section 25.254 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Technical...

Conjugated heat transfer in laminar flow between parallel-plates channel

International Nuclear Information System (INIS)

Guedes, R.O.C.; Cotta, R.M.; Brum, N.C.L.

1989-01-01

An analysis is made of conjugated convective-conductive heat transfer in laminar flow of a newtonian fluid between parallel-plates channel, taking into account the longitudinal conduction along the duct walls only, by neglecting the transversal temperature gradients in the solid. This extended Graetz-type problem is then analytically handled through the generalized integral transform technique, providing accurate numerical results for quantities of practical interest sucyh as bulk and wall temperatures, and Nusselt numbers. The effects of a conjugation parameter and Biot number on heat transfer behavior are then investigated. (author)

Effects of preheated combustion air on laminar coflow diffusion flames under normal and microgravity conditions

Science.gov (United States)

Ghaderi Yeganeh, Mohammad

Global energy consumption has been increasing around the world, owing to the rapid growth of industrialization and improvements in the standard of living. As a result, more carbon dioxide and nitrogen oxide are being released into the environment. Therefore, techniques for achieving combustion at reduced carbon dioxide and nitric oxide emission levels have drawn increased attention. Combustion with a highly preheated air and low-oxygen concentration has been shown to provide significant energy savings, reduce pollution and equipment size, and uniform thermal characteristics within the combustion chamber. However, the fundamental understanding of this technique is limited. The motivation of the present study is to identify the effects of preheated combustion air on laminar coflow diffusion flames. Combustion characteristics of laminar coflow diffusion flames are evaluated for the effects of preheated combustion air temperature under normal and low-gravity conditions. Experimental measurements are conducted using direct flame photography, particle image velocimetry (PIV) and optical emission spectroscopy diagnostics. Laminar coflow diffusion flames are examined under four experimental conditions: normal-temperature/normal-gravity (case I), preheated-temperature/normal gravity (case II), normal-temperature/low-gravity (case III), and preheated-temperature/low-gravity (case IV). Comparisons between these four cases yield significant insights. In our studies, increasing the combustion air temperature by 400 K (from 300 K to 700 K), causes a 37.1% reduction in the flame length and about a 25% increase in peak flame temperature. The results also show that a 400 K increase in the preheated air temperature increases CH concentration of the flame by about 83.3% (CH is a marker for the rate of chemical reaction), and also increases the C2 concentration by about 60% (C2 is a marker for the soot precursor). It can therefore be concluded that preheating the combustion air

Direct numerical simulation of laminar-turbulent flow over a flat plate at hypersonic flow speeds

Science.gov (United States)

Egorov, I. V.; Novikov, A. V.

2016-06-01

A method for direct numerical simulation of a laminar-turbulent flow around bodies at hypersonic flow speeds is proposed. The simulation is performed by solving the full three-dimensional unsteady Navier-Stokes equations. The method of calculation is oriented to application of supercomputers and is based on implicit monotonic approximation schemes and a modified Newton-Raphson method for solving nonlinear difference equations. By this method, the development of three-dimensional perturbations in the boundary layer over a flat plate and in a near-wall flow in a compression corner is studied at the Mach numbers of the free-stream of M = 5.37. In addition to pulsation characteristic, distributions of the mean coefficients of the viscous flow in the transient section of the streamlined surface are obtained, which enables one to determine the beginning of the laminar-turbulent transition and estimate the characteristics of the turbulent flow in the boundary layer.

Autoignition characteristics of laminar lifted jet flames of pre-vaporized iso-octane in heated coflow air

KAUST Repository

Al-Noman, Saeed M.; Choi, Sang Kyu; Chung, Suk-Ho

2015-01-01

The stabilization characteristics of laminar non-premixed jet flames of pre-vaporized iso-octane, one of the primary reference fuels for octane rating, have been studied experimentally in heated coflow air. Non-autoignited and autoignited lifted

Linear Stability Analysis of Laminar Premixed Fuel-Rich Double-Spray Flames

Directory of Open Access Journals (Sweden)

Noam Weinberg

2014-03-01

Full Text Available This paper considers the stability of a double-spray premixed flame formed when both fuel and oxidizer are initially present in the form of sprays of evaporating liquid droplets. To simplify the inherent complexity that characterizes the analytic solution of multi-phase combustion processes, the analysis is restricted to fuel-rich laminar premixed double-spray flames, and assumes a single-step global chemical reaction mechanism. Steady-state solutions are obtained and the sensitivity of the flame temperature and the flame propagating velocity to the initial liquid fuel and/or oxidizer loads are established. The stability analysis revealed an increased proneness to cellular instability induced by the presence of the two sprays, and for the fuel-rich case considered here the influence of the liquid oxidizer was found to be more pronounced than that of the liquid fuel. Similar effects were noted for the neutral pulsating stability boundaries. The impact of unequal latent heats of vaporization is also investigated and found to be in keeping with the destabilizing influence of heat loss due to droplet evaporation. It should be noted that as far as the authors are aware no experimental evidence is available for (at least validation of the predictions. However, they do concur in a general and reasonable fashion with independent experimental evidence in the literature of the behavior of single fuel spray laminar premixed flames.

INCOMPRESSIBLE LAMINAR BOUNDARY LAYER CONTROL BY BLOWING AND SUCTION

Directory of Open Access Journals (Sweden)

AZZEDINE NAHOUI

2013-12-01

Full Text Available A two-dimensional incompressible laminar boundary layer and its control using blowing and suction over a flat plate and around the NACA 0012 and 661012 profiles, is studied numerically. The study is based on the Prandtl boundary layer model using the finite differences method and the Crank-Nicolson scheme. The velocity distribution, the boundary layer thickness and the friction coefficient, are determined and presented with and without control. The application of the control technique, has demonstrated its positive effect on the transition point and the friction coefficient. Both control procedures are compared for different lengths, speeds and angles of blowing and suction.

Urology Group Compensation and Ancillary Service Models in an Era of Value-based Care.

Science.gov (United States)

Shore, Neal D; Jacoby, Dana

2016-01-01

Changes involving the health care economic landscape have affected physicians' workflow, productivity, compensation structures, and culture. Ongoing Federal legislation regarding regulatory documentation and imminent payment-changing methodologies have encouraged physician consolidation into larger practices, creating affiliations with hospitals, multidisciplinary medical specialties, and integrated delivery networks. As subspecialization and evolution of care models have accelerated, independent medical groups have broadened ancillary service lines by investing in enterprises that compete with hospital-based (academic and nonacademic) entities, as well as non-physician- owned multispecialty enterprises, for both outpatient and inpatient services. The looming and dramatic shift from volume- to value-based health care compensation will assuredly affect urology group compensation arrangements and productivity formulae. For groups that can implement change rapidly, efficiently, and harmoniously, there will be opportunities to achieve the Triple Aim goals of the Patient Protection and Affordable Care Act, while maintaining a successful medical-financial practice. In summary, implementing new payment algorithms alongside comprehensive care coordination will assist urology groups in addressing the health economic cost and quality challenges that have been historically encountered with fee-for-service systems. Urology group leadership and stakeholders will need to adjust internal processes, methods of care coordination, cultural dependency, and organizational structures in order to create better systems of care and management. In response, ancillary services and patient throughput will need to evolve in order to adequately align quality measurement and reporting systems across provider footprints and patient populations.

Characteristics of autoignited laminar lifted flames in heated coflow jets of carbon monoxide/hydrogen mixtures

KAUST Repository

Choi, Byungchul; Chung, Suk-Ho

2012-01-01

and then increased as the jet velocity increased. Based on the mechanism in which the autoignited laminar lifted flame is stabilized by ignition delay time, the liftoff height can be influenced not only by the heat loss, but also by the preferential diffusion between

Indeterminacy of drag exerted on an arrow in free flight: arrow attitude and laminar-turbulent transition

Science.gov (United States)

Miyazaki, T.; Matsumoto, T.; Ando, R.; Ortiz, J.; Sugiura, H.

2017-11-01

The aerodynamic properties of an arrow (A/C/E; Easton) were investigated in an extension of our previous work, in which the laminar-turbulent transition of the boundary layer on the arrow shaft was found to take place in the Re number range of 1.2 × 104 aligned with the flow, the boundary layer remains laminar for Re < 1.5 × 104, and the drag coefficient is approximately 1.5 for 1.0 × 104 < Re < 1.5 × 104. If the arrow has an angle of attack of 0.75 ° with the flow, the transition to turbulence takes place at approximately Re = 1.1 × 104, and the drag coefficient increases to approximately 3.1. In addition, free flight experiments are performed. The arrow’s velocity and angular velocity are recorded using five high-speed video cameras. By analysing the recorded images, we obtain the initial and final velocities from which the drag coefficient is determined. The trajectory and attitude of the arrow in free flight are computed numerically by integrating the equations of motion for a rigid body using the initial data obtained from the video images. The laminar-turbulent transition of the boundary layer is shown to take place, if the maximum angle of attack exceeds about 0.4° at Re = 1.75 × 104. The crucial influence of the initial angular velocity on the angle of attack is also examined.

Combustion and radiation modeling of laminar premixed flames using OpenFOAM: A numerical investigation of radiative heat transfer in the RADIADE project

OpenAIRE

Haider, Sajjad; Pang, Kar Mun; Ivarsson, Anders; Schramm, Jesper

2013-01-01

This paper presents the computational fluid dynamics modelling of a laminar premixed flame. A specific solver named ’rareLTSFoam’ is developed using OpenFOAM ® code. The solver is used to simulate experimental stoichiometric and rich laminar premixed flames. The modelling is carried out for thermal flow and combusting flow cases. The results show that without including radiation modelling, the predicted flame temperature is higher than the measured values. P1 radiation Model is used with sub-...

A realistic neural mass model of the cortex with laminar-specific connections and synaptic plasticity - evaluation with auditory habituation.

Directory of Open Access Journals (Sweden)

Peng Wang

Full Text Available In this work we propose a biologically realistic local cortical circuit model (LCCM, based on neural masses, that incorporates important aspects of the functional organization of the brain that have not been covered by previous models: (1 activity dependent plasticity of excitatory synaptic couplings via depleting and recycling of neurotransmitters and (2 realistic inter-laminar dynamics via laminar-specific distribution of and connections between neural populations. The potential of the LCCM was demonstrated by accounting for the process of auditory habituation. The model parameters were specified using Bayesian inference. It was found that: (1 besides the major serial excitatory information pathway (layer 4 to layer 2/3 to layer 5/6, there exists a parallel "short-cut" pathway (layer 4 to layer 5/6, (2 the excitatory signal flow from the pyramidal cells to the inhibitory interneurons seems to be more intra-laminar while, in contrast, the inhibitory signal flow from inhibitory interneurons to the pyramidal cells seems to be both intra- and inter-laminar, and (3 the habituation rates of the connections are unsymmetrical: forward connections (from layer 4 to layer 2/3 are more strongly habituated than backward connections (from Layer 5/6 to layer 4. Our evaluation demonstrates that the novel features of the LCCM are of crucial importance for mechanistic explanations of brain function. The incorporation of these features into a mass model makes them applicable to modeling based on macroscopic data (like EEG or MEG, which are usually available in human experiments. Our LCCM is therefore a valuable building block for future realistic models of human cognitive function.

Effects of optical diagnostic techniques on the accuracy of laminar flame speeds measured from Bunsen flames: OH* chemiluminescence, OH-PLIF and acetone/kerosene-PLIF

Science.gov (United States)

Wu, Yi; Modica, Vincent; Yu, Xilong; Li, Fei; Grisch, Frédéric

2018-01-01

The effects of optical diagnostic techniques on the accuracy of laminar flame speed measured from Bunsen flames were investigated. Laminar flame speed measurements were conducted for different fuel/air mixtures including CH4/air, acetone/air and kerosene (Jet A-1)/air in applying different optical diagnostic techniques, i.e. OH* chemiluminescence, OH-PLIF and acetone/kerosene-PLIF. It is found that the OH* chemiluminescence imaging technique cannot directly derive the location of the outer edge of the fresh gases and it is necessary to correct the position of the OH* peak to guarantee the accuracy of the measurements. OH-PLIF and acetone/kerosene-PLIF respectively are able to measure the disappearance of the fresh gas contour and the appearance of the reaction zone. It shows that the aromatic-PLIF technique gives similar laminar flame speed values when compared with those obtained from corrected OH* chemiluminescence images. However, discrepancies were observed between the OH-PLIF and the aromatic-PLIF techniques, in that OH-PLIF slightly underestimates laminar flame speeds by up to 5%. The difference between the flame contours obtained from different optical techniques are further analysed and illustrated with 1D flame structure simulation using detailed kinetic mechanisms.

Hydrodynamics of piston-driven laminar pulsating flow: Part 2. Fully developed flow

International Nuclear Information System (INIS)

Aygun, Cemalettin; Aydin, Orhan

2014-01-01

Highlights: • The piston-driven laminar pulsating flow in a pipe is studied. • Fully developed flow is examined analytically, numerically and experimentally. • An increase in F results an increase in the amplitude of the centerline velocity. • The characters of the radial velocity profiles critically depend on both the frequency and the phase angle. • The near/off-wall flow reversals are observed for F = 105, 226 and 402. - Abstract: Piston-driven pulsating flow is a specific type of pressure-driven pulsating flows. In this study, piston-driven laminar pulsating flow in a pipe is studied. This study mainly exists of two parts: developing flow and fully developed flow. In this part, hydrodynamically fully developed flow is examined analytically, numerically and experimentally. A constant value of the time-averaged Reynolds number is considered, Re = 1000. In the theoretical studies, both analytical and numerical, an inlet velocity profile representing the experimental case, i.e., the piston driven flow, is assumed. In the experiments, in the hydrodynamically fully developed region, radial velocity distribution and pressure drop are obtained using hot-wire anemometer and pressure transmitter, respectively. The effect pulsation frequency on the friction coefficient as well as velocity profiles are obtained. A good agreement is observed among analytical, numerical and experimental results

Morphology combined with ancillary techniques: An algorithm approach for thyroid nodules.

Science.gov (United States)

Rossi, E D; Martini, M; Capodimonti, S; Cenci, T; Bilotta, M; Pierconti, F; Pontecorvi, A; Lombardi, C P; Fadda, G; Larocca, L M

2018-04-23

Several authors have underlined the limits of morphological analysis mostly in the diagnosis of follicular neoplasms (FN). The application of ancillary techniques, including immunocytochemistry (ICC) and molecular testing, contributes to a better definition of the risk of malignancy (ROM) and management of FN. According to literature, the application of models, including the evaluation of ICC, somatic mutations (ie, BRAF V 600E ), micro RNA analysis is proposed for FNs. This study discusses the validation of a diagnostic algorithm in FN with a special focus on the role of morphology then followed by ancillary techniques. From June 2014 to January 2016, we enrolled 37 FNs with histological follow-up. In the same reference period, 20 benign nodules and 20 positive for malignancy were selected as control. ICC, BRAF V 600E mutation and miR-375 were carried out on LBC. The 37 FNs included 14 atypia of undetermined significance/follicular lesion of undetermined significance and 23 FN. Specifically, atypia of undetermined significance/follicular lesion of undetermined significance resulted in three goitres, 10 follicular adenomas and one NIFTP whereas FN/suspicious for FN by seven follicular adenomas and 16 malignancies (nine non-invasive follicular thyroid neoplasms with papillary-like nuclear features, two invasive follicular variant of papillary thyroid carcinoma [PTC] and five PTC). The 20 positive for malignancy samples included two invasive follicular variant of PTC, 16 PTCs and two medullary carcinomas. The morphological features of BRAF V 600E mutation (nuclear features of PTC and moderate/abundant eosinophilic cytoplasms) were associated with 100% ROM. In the wild type cases, ROM was 83.3% in presence of a concordant positive ICC panel whilst significantly lower (10.5%) in a negative concordant ICC. High expression values of MirR-375 provided 100% ROM. The adoption of an algorithm might represent the best choice for the correct diagnosis of FNs. The morphological

Boundary layer control by a fish: Unsteady laminar boundary layers of rainbow trout swimming in turbulent flows.

Science.gov (United States)

Yanase, Kazutaka; Saarenrinne, Pentti

2016-12-15

The boundary layers of rainbow trout, Oncorhynchus mykiss [0.231±0.016 m total body length (L) (mean±s.d.); N=6], swimming at 1.6±0.09 L s -1 (N=6) in an experimental flow channel (Reynolds number, Re=4×10 5 ) with medium turbulence (5.6% intensity) were examined using the particle image velocimetry technique. The tangential flow velocity distributions in the pectoral and pelvic surface regions (arc length from the rostrum, l x =71±8 mm, N=3, and l x =110±13 mm, N=4, respectively) were approximated by a laminar boundary layer model, the Falkner-Skan equation. The flow regime over the pectoral and pelvic surfaces was regarded as a laminar flow, which could create less skin-friction drag than would be the case with turbulent flow. Flow separation was postponed until vortex shedding occurred over the posterior surface (l x =163±22 mm, N=3). The ratio of the body-wave velocity to the swimming speed was in the order of 1.2. This was consistent with the condition of the boundary layer laminarization that had been confirmed earlier using a mechanical model. These findings suggest an energy-efficient swimming strategy for rainbow trout in a turbulent environment. © 2016. Published by The Company of Biologists Ltd.

Acoustic detection of momentum transfer during the abrupt transition from a laminar to a turbulent atmospheric boundary layer1

International Nuclear Information System (INIS)

Schubert, J.F.

1977-01-01

Acoustic sounder measurements of a vertical profile of the abrupt transition from a laminar to a turbulent atmospheric boundary layer were compared with meteorological measurements made at 10 and 137 m on an instrumented tower. Sounder data show that conditions necessary for the onset of the momentum burst phenomenon exist sometime during a clear afternoon when heat flux changes sign and the planetary surface cools. Under these conditions, the lowest part of the atmospheric boundary layer becomes stable. Prior to this situation, the entire boundary layer is in turbulent motion from surface heating. The boundary layer is then an effective barrier for all fluxes, and as the maximum flux Richardson number is reached at some height close to but above the surface, turbulence is dampened and a laminar layer forms. The profile of this layer is recorded by the sounder. Surface temperature drops, a strong wind shear develops, and the Richardson number decreases below its critical value (Ri/sub cr/<0.25). Subsequently, the laminar layer is eroded by turbulence from above, and with a burst of momentum and heat, it eventually reaches the ground

Compilation, quality control, analysis, and summary of discrete suspended-sediment and ancillary data in the United States, 1901-2010

Science.gov (United States)

Lee, Casey J.; Glysson, G. Douglas

2013-01-01

Human-induced and natural changes to the transport of sediment and sediment-associated constituents can degrade aquatic ecosystems and limit human uses of streams and rivers. The lack of a dedicated, easily accessible, quality-controlled database of sediment and ancillary data has made it difficult to identify sediment-related water-quality impairments and has limited understanding of how human actions affect suspended-sediment concentrations and transport. The purpose of this report is to describe the creation of a quality-controlled U.S. Geological Survey suspended-sediment database, provide guidance for its use, and summarize characteristics of suspended-sediment data through 2010. The database is provided as an online application at http://cida.usgs.gov/sediment to allow users to view, filter, and retrieve available suspended-sediment and ancillary data. A data recovery, filtration, and quality-control process was performed to expand the availability, representativeness, and utility of existing suspended-sediment data collected by the U.S. Geological Survey in the United States before January 1, 2011. Information on streamflow condition, sediment grain size, and upstream landscape condition were matched to sediment data and sediment-sampling sites to place data in context with factors that may influence sediment transport. Suspended-sediment and selected ancillary data are presented from across the United States with respect to time, streamflow, and landscape condition. Examples of potential uses of this database for identifying sediment-related impairments, assessing trends, and designing new data collection activities are provided. This report and database can support local and national-level decision making, project planning, and data mining activities related to the transport of suspended-sediment and sediment-associated constituents.

Comparison between mixed and laminar airflow systems in operating rooms and the influence of human factors: experiences from a Swedish orthopedic center.

Science.gov (United States)

Erichsen Andersson, Annette; Petzold, Max; Bergh, Ingrid; Karlsson, Jón; Eriksson, Bengt I; Nilsson, Kerstin

2014-06-01

The importance of laminar airflow systems in operating rooms as protection from surgical site infections has been questioned. The aim of our study was to explore the differences in air contamination rates between displacement ventilation and laminar airflow systems during planned and acute orthopedic implant surgery. A second aim was to compare the influence of the number of people present, the reasons for traffic flow, and the door-opening rates between the 2 systems. Active air sampling and observations were made during 63 orthopedic implant operations. The laminar airflow system resulted in a reduction of 89% in colony forming units in comparison with the displacement system (P operating rooms offer high-quality air during surgery, with very low levels of colony forming units close to the surgical wound. The continuous maintenance of laminar air flow and other technical systems are crucial, because minor failures in complex systems like those in operating rooms can result in a detrimental effect on air quality and jeopardize the safety of patients. The technical ventilation solutions are important, but they do not guarantee clean air, because many other factors, such as the organization of the work and staff behavior, influence air cleanliness. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Coupling of conduction with laminar free convection from a vertical flat plate - an experimental study

International Nuclear Information System (INIS)

Aharon, J.; Lahav, C.; Kalman, H.; Shai, I.

1996-01-01

The present work deals with natural convection on a vertical flat plate, where one side of the plate is maintained at a uniform temperature - T a , and the other side of the plate is exposed to an environment of constant temperature -T∞. The plate is consisted of several layers of conductive and non-conductive materials such that the series thermal resistance can be expressed as an equivalent heat transfer coefficient h eq 1/Σ(k i /d i ). It is also assumed a negligible axial conduction, which can be neglected. The present investigation treats the heat transfer problem in the laminar zone in air (P r ∼1). The wall effective heat transfer coefficient is in the range of 4.3 to 11.5 W/m 2 - deg C. An experimental apparatus was constructed to confirm the heat transfer features predicted analytically in a previous work. The local experimental Nusselt number was correlated with the modified Rayleigh number, for the laminar range (authors)

Assessment of CFD Capability for Hypersonic Shock Wave Laminar Boundary Layer Interactions

OpenAIRE

Mehrnaz Rouhi Youssefi; Doyle Knight

2017-01-01

The goal of this study is to assess CFD capability for the prediction of shock wave laminar boundary layer interactions at hypersonic velocities. More specifically, the flow field over a double-cone configuration is simulated using both perfect gas and non-equilibrium Navier–Stokes models. Computations are compared with recent experimental data obtained from measurements conducted in the LENS XX (Large Energy National Shock Expansion Tunnel Version 2) at the Calspan University of Buffalo Rese...

Analogy of convective heat transfer between developing laminar secondary flows in pipes

OpenAIRE

Ishigaki, Hiroshi; 石垣　博

1998-01-01

Analogy of convective heat transfer between developing laminar flows in curved pipes and orthogonally rotating pipes is described through similarity arguments and numerical computation. Governing parameters and a dimensionless axial distance are properly used for the respective flows. When the second parameter is large in each flow, it is shown that the temperature profiles and the Nusselt numbers of the two flows are approximately similar for the same values of the governing parameter, Prand...

Preliminary Results of Ancillary Safety Analyses Supporting TREAT LEU Conversion Activities

Energy Technology Data Exchange (ETDEWEB)

Brunett, A. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Fei, T. [Argonne National Lab. (ANL), Argonne, IL (United States); Strons, P. S. [Argonne National Lab. (ANL), Argonne, IL (United States); Papadias, D. D. [Argonne National Lab. (ANL), Argonne, IL (United States); Hoffman, E. A. [Argonne National Lab. (ANL), Argonne, IL (United States); Kontogeorgakos, D. C. [Argonne National Lab. (ANL), Argonne, IL (United States); Connaway, H. M. [Argonne National Lab. (ANL), Argonne, IL (United States); Wright, A. E. [Argonne National Lab. (ANL), Argonne, IL (United States)

2015-10-01

The Transient Reactor Test Facility (TREAT), located at Idaho National Laboratory (INL), is a test facility designed to evaluate the performance of reactor fuels and materials under transient accident conditions. The facility, an air-cooled, graphite-moderated reactor designed to utilize fuel containing high-enriched uranium (HEU), has been in non-operational standby status since 1994. Currently, in support of the missions of the Department of Energy (DOE) National Nuclear Security Administration (NNSA) Material Management and Minimization (M3) Reactor Conversion Program, a new core design is being developed for TREAT that will utilize low-enriched uranium (LEU). The primary objective of this conversion effort is to design an LEU core that is capable of meeting the performance characteristics of the existing HEU core. Minimal, if any, changes are anticipated for the supporting systems (e.g. reactor trip system, filtration/cooling system, etc.); therefore, the LEU core must also be able to function with the existing supporting systems, and must also satisfy acceptable safety limits. In support of the LEU conversion effort, a range of ancillary safety analyses are required to evaluate the LEU core operation relative to that of the existing facility. These analyses cover neutronics, shielding, and thermal hydraulic topics that have been identified as having the potential to have reduced safety margins due to conversion to LEU fuel, or are required to support the required safety analyses documentation. The majority of these ancillary tasks have been identified in [1] and [2]. The purpose of this report is to document the ancillary safety analyses that have been performed at Argonne National Laboratory during the early stages of the LEU design effort, and to describe ongoing and anticipated analyses. For all analyses presented in this report, methodologies are utilized that are consistent with, or improved from, those used in analyses for the HEU Final Safety Analysis

Propagation of atmospheric pressure helium plasma jet into ambient air at laminar gas flow

International Nuclear Information System (INIS)

Pinchuk, M; Kurakina, N; Spodobin, V; Stepanova, O

2017-01-01

The formation of an atmospheric pressure plasma jet (APPJ) in a gas flow passing through the discharge gap depends on both gas-dynamic properties and electrophysical parameters of the plasma jet generator. The paper presents the results of experimental and numerical study of the propagation of the APPJ in a laminar flow of helium. A dielectric-barrier discharge (DBD) generated inside a quartz tube equipped with a coaxial electrode system, which provided gas passing through it, served as a plasma source. The transition of the laminar regime of gas flow into turbulent one was controlled by the photography of a formed plasma jet. The corresponding gas outlet velocity and Reynolds numbers were revealed experimentally and were used to simulate gas dynamics with OpenFOAM software. The data of the numerical simulation suggest that the length of plasma jet at the unvarying electrophysical parameters of DBD strongly depends on the mole fraction of ambient air in a helium flow, which is established along the direction of gas flow. (paper)

A New Approach to Laminar Flowmeters

Directory of Open Access Journals (Sweden)

Alvaro Deibe

2010-11-01

Full Text Available After studying the performance and characteristics of actual laminar flowmeters a new disposition for this type of sensors is proposed in such a way that the measurement errors introduced by the intrinsic nature of the device can be minimized. The preliminary study shows that the developing entry region introduces non-linearity effects in all these devices. These effects bring about not only errors, but also a change in the slope of the linear calibration respect of the Poiseuille relation. After a subsequent analysis on how these non-linearity errors can be reduced, a new disposition of this type of flowmeters is introduced. This device makes used of flow elements having pressure taps at three locations along its length and connected to three isolated chambers. In this way, the static pressure can be measured at three locations and contributed to by the pressure taps at the level of each chamber. Thus the linearization error is reduced with an additional advantage of producing a reduced pressure drop.

Acute hepatic encephalopathy presenting as cortical laminar necrosis: Case report

International Nuclear Information System (INIS)

Choi, Jong Mun; Kim, Yoon Hee; Roh, Sook Young

2013-01-01

We report on a 55-year-old man with alcoholic liver cirrhosis who presented with status epilepticus. Laboratory analysis showed markedly elevated blood ammonia. Brain magnetic resonance imaging (MRI) showed widespread cortical signal changes with restricted diffusion, involving both temporo-fronto-parietal cortex, while the perirolandic regions and occipital cortex were uniquely spared. A follow-up brain MRI demonstrated diffuse cortical atrophy with increased signals on T1-weighted images in both the basal ganglia and temporal lobe cortex, representing cortical laminar necrosis. We suggest that the brain lesions, in our case, represent a consequence of toxic effect of ammonia.

Acute hepatic encephalopathy presenting as cortical laminar necrosis: Case report

Energy Technology Data Exchange (ETDEWEB)

Choi, Jong Mun; Kim, Yoon Hee; Roh, Sook Young [Bundang Jesaeng General Hospital, Daejin Medical Center, Seongnam (Korea, Republic of)

2013-04-15

We report on a 55-year-old man with alcoholic liver cirrhosis who presented with status epilepticus. Laboratory analysis showed markedly elevated blood ammonia. Brain magnetic resonance imaging (MRI) showed widespread cortical signal changes with restricted diffusion, involving both temporo-fronto-parietal cortex, while the perirolandic regions and occipital cortex were uniquely spared. A follow-up brain MRI demonstrated diffuse cortical atrophy with increased signals on T1-weighted images in both the basal ganglia and temporal lobe cortex, representing cortical laminar necrosis. We suggest that the brain lesions, in our case, represent a consequence of toxic effect of ammonia.

Feasibility Demonstration of Exciplex Fluorescence Measurements in Evaporating Laminar Sprays of Diesel Fuel

Science.gov (United States)

2011-05-15

code) 1 FEASIBILITY DEMONSTRATION OF EXCIPLEX FLUORESCENCE MEASUREMENTS IN EVAPORATING LAMINAR SPRAYS OF DIESEL FUEL Final Technical Report Grant...fluorescence is found to increase with temperature up to 538 K and then declines. Fluorescence from the liquid phase, i.e. the exciplex (Naphthalene+TMPD...to have as well characterized a description of the spray environment and assess conclusively the potential of the exciplex approach for more

Laminar dispersion in parallel plate sections of flowing systems used in analytical chemistry and chemical engineering

NARCIS (Netherlands)

Kolev, S.D.; Kolev, Spas D.; van der Linden, W.E.

1991-01-01

An exact solution of the convective-diffusion equation for fully developed parallel plate laminar flow was obtained. It allows the derivation of theoretical relationships for calculating the Peclet number in the axially dispersed plug flow model and the concentration distribution perpendicular to

Serial MR observation of cortical laminar necrosis caused by brain infarction

Energy Technology Data Exchange (ETDEWEB)

Komiyama, M.; Nakajima, H.; Nishikawa, M.; Yasui, T. [Department of Neurosurgery, Osaka City General Hospital (Japan)

1998-12-01

To examine the chronological changes characteristic of cortical laminar necrosis caused by brain infarction, 16 patients were repeatedly examined using T1-, T2-weighted spin-echo, T2{sup *}-weighted gradient echo, fluid attenuated inversion recovery (FLAIR) images, and contrast enhanced T1-weighted images at 1.0 or 1.5 T. High intensity cortical lesions were visible on the T1-weighted images from 2 weeks after ictus and became prominent at 1 to 3 months, then became less apparent, but occasionally remained at high intensity for 2 years. High intensity cortical lesions on FLAIR images became prominent from 1 month, and then became less prominent from 1 year, but occasionally remained at high intensity for 2 years. Subcortical lesions did not display high intensity on T1-weighted images at any stage. On FLAIR images, subcortical lesions initially showed slightly high intensity and then low intensity from 6 months due to encephalomalacia. Cortical lesions showed prominent contrast enhancement from 2 weeks to 3 months, but subcortical lesions were prominent from 2 weeks only up to 1 month. T2*-weighted images disclosed haemosiderin in 3 of 7 patients, but there was no correlation with cortical short T1 lesions. Cortical laminar necrosis showed characteristic chronological signal changes on T1-weighted images and FLAIR images. Cortical short T1 lesions were found not to be caused by haemorrhagic infarction. (orig.) With 5 figs., 1 tab., 9 refs.

Laminar and dorsoventral molecular organization of the medial entorhinal cortex revealed by large-scale anatomical analysis of gene expression.

Directory of Open Access Journals (Sweden)

Helen L Ramsden

2015-01-01

Full Text Available Neural circuits in the medial entorhinal cortex (MEC encode an animal's position and orientation in space. Within the MEC spatial representations, including grid and directional firing fields, have a laminar and dorsoventral organization that corresponds to a similar topography of neuronal connectivity and cellular properties. Yet, in part due to the challenges of integrating anatomical data at the resolution of cortical layers and borders, we know little about the molecular components underlying this organization. To address this we develop a new computational pipeline for high-throughput analysis and comparison of in situ hybridization (ISH images at laminar resolution. We apply this pipeline to ISH data for over 16,000 genes in the Allen Brain Atlas and validate our analysis with RNA sequencing of MEC tissue from adult mice. We find that differential gene expression delineates the borders of the MEC with neighboring brain structures and reveals its laminar and dorsoventral organization. We propose a new molecular basis for distinguishing the deep layers of the MEC and show that their similarity to corresponding layers of neocortex is greater than that of superficial layers. Our analysis identifies ion channel-, cell adhesion- and synapse-related genes as candidates for functional differentiation of MEC layers and for encoding of spatial information at different scales along the dorsoventral axis of the MEC. We also reveal laminar organization of genes related to disease pathology and suggest that a high metabolic demand predisposes layer II to neurodegenerative pathology. In principle, our computational pipeline can be applied to high-throughput analysis of many forms of neuroanatomical data. Our results support the hypothesis that differences in gene expression contribute to functional specialization of superficial layers of the MEC and dorsoventral organization of the scale of spatial representations.

Vehicle Ancillary Load Reduction Project Close-Out Report: An Overview of the Task and a Compilation of the Research Results

Energy Technology Data Exchange (ETDEWEB)

Rugh, J.; Farrington, R.

2008-01-01

The amount of fuel used for climate control in U.S. vehicles reduces the fuel economy of more than 200 million light-duty conventional vehicles and thus affects U.S. energy security. Researchers at the DOE National Renewable Energy Laboratory estimated that the United States consumes about 7 billion gallons of fuel per year for air-conditioning (A/C) light-duty vehicles. Using a variety of tools, NREL researchers developed innovative techniques and technologies to reduce the amount of fuel needed for these vehicles' ancillary loads. For example, they found that the A/C cooling capacity of 5.7 kW in a Cadillac STS could be reduced by 30% while maintaining a cooldown performance of 30 minutes. A simulation showed that reducing the A/C load by 30% decreased A/C fuel consumption by 26%. Other simulations supported the great potential for improving fuel economy by using new technologies and techniques developed to reduce ancillary loads.

Cubierta laminar prefabricada, Suiza

Directory of Open Access Journals (Sweden)

Hossdorf, Heinz

1964-04-01

Full Text Available The roof constructed recently near Olten, in Switzerland, consists of a series of cylindrical shell surfaces, with skylights between the successive shells. It covers an area of 13.500 m2, and the building is to be used as a storehouse and servicing installation for the Federation of Consumer Goods Society. The general nature of the design made it logical, from the outset, to construct the roof as a number of similar prefabricated units. This method had evident economic advantages. The repetition of similar cylindrical roof sections made it possible to reiterate also the particular constructive process which was adopted in this case. The prefabricated shell units have been reinforced with lateral ribs, which make them sufficiently stiff to be handled at the working site. Each unit is 25.20 m long and spans a width of 1.40 ms. The roof is made up of 18 such elements. A feature of this roof is that it has been subjected to a prestressing process, applied by cables, running along the extrados of the cylindrical surface of each unit. This improves the stability and strength of the shells, and induces favourable stresses which counteract noticeably the effects of the shear forces and bending moments. The edges of these shells have been reinforced by increasing the thickness of the ribs, thereby improving the end anchorage. In order to check the theoretical calculations for this structure, several tests were carried out on scale models.La cubierta recientemente construida en las cercanías de Olten (Suiza, de tipo laminar, especial, curvada, constituida por una serie de superficies cilíndricas sucesivas y con lucernario en las soluciones de continuidad que cada par de superficies parciales cilíndricas motiva, tiene por principal objeto cubrir una superficie de 13.500 m2 edificados con destino a los servicios y explotación de un almacén de la Federación de Sociedades de Consumo. Debido a las ideas generales básicas del proyecto se impuso, desde un

Engineering Evaluation/Cost Analysis for the 100-N Area Ancillary Facilities and Integration Plan

International Nuclear Information System (INIS)

Mukherjee, B.

1997-09-01

This document presents the results of an engineering evaluation/cost analysis (EE/CA) that was conducted to evaluate alternatives for addressing final disposition of contaminated buildings and structures in the 100-N Area of the Hanford Site. The Hanford Site is located in southeastern Washington State and is owned by the U.S. Government and operated by the U.S. Department of Energy, Richland Operations Office (RL). In November 1989, the 100 Area of the Hanford Site (as well as the 200, 300, and 1100 Areas) was placed on the U.S. Environmental Protection Agency's National Priorities List (NPL) under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980. The 100 Area NPL includes the 100-N Area, which is in various stages of the remediation process. It has been determined by RL that hazardous substances in the 100-N Area ancillary facilities may present a potential threat to human health or the environment, and that a non-time critical removal action at these facilities is warranted. To help determine the most appropriate action, RL, in cooperation with the Washington State Department of Ecology (Ecology) and the EPA, has prepared this EE/CA. The scope of the evaluation includes the inactive contaminated ancillary facilities in the 100-N Area, the facilities residing in the buffer zone, and the Hanford Generating Plant (HGP) and the solid waste management units (SWMUs) inside HGP support facilities. The 105-N Reactor and 109-N Heat Exchange facilities are excluded from this EE/CA evaluation

Development of modified rational buyer auction for procurement of ancillary services utilizing participation matrix

International Nuclear Information System (INIS)

Jamalzadeh, R.; Ardehali, M.M.; Rashidinejad, M.

2008-01-01

The rational buyer auction is based on a simultaneous auction that is the redesigned auction mechanism for ancillary services by the California independent system operator (CAISO). The incentive for the rational buyer auction is CAISO's intent to adopt a common sense rule of substituting higher-quality lower-cost services for lower-quality higher-cost services, when it results in reduced total procurement cost. For the purposes of designing a desirable auction where the minimum cost for the objective function as well as prevention of price reversal are achieved, either the payment cost in marginal pricing auction must be lowered or price reversal in rational buyer auction must be avoided. The objectives of this study are (a) to develop a newly proposed 'modified rational buyer' auction that does not allow price reversal and (b) to propose and validate a solution procedure that is based on participation matrix and discrete programming. The validation of the proposed solution procedure is accomplished through examination of two case studies available in the literature. Based on the first case study data, it is shown that the newly developed modified rational buyer auction avoids price reversal occurrence, while the total payment of ISO is increased by 5.8%, as compared with rational buyer auction. Also in comparison with marginal pricing auction, the ISO payment is lowered by 38.8%, when the newly developed modified rational buyer auction is utilized. For future work, it is recommended that the application of the modified rational buyer auction to joint dispatch of energy and ancillary services is investigated

Laminar thickness alterations in the fronto-parietal cortical mantle of patients with attention-deficit/hyperactivity disorder.

Directory of Open Access Journals (Sweden)

Elseline Hoekzema

Full Text Available Although Attention-Deficit/Hyperactivity Disorder (ADHD was initially regarded as a disorder exclusive to childhood, nowadays its prevalence in adulthood is well established. The development of novel techniques for quantifying the thickness of the cerebral mantle allows the further exploration of the neuroanatomical profiles underlying the child and adult form of the disorder. To examine the cortical mantle in children and adults with ADHD, we applied a vertex-wise analysis of cortical thickness to anatomical brain MRI scans acquired from children with (n = 43 and without ADHD (n = 41, as well as a group of adult neurotypical individuals (n = 31, adult patients with a history of stimulant treatment (n = 31 and medication-naïve adults with ADHD (n = 24. We observed several clusters of reduced laminar cortical thickness in ADHD patients in comparison to neurotypical individuals. These differences were primarily located in the dorsal attention network, including the bilateral inferior and superior parietal cortex and a section of the frontal cortex (centered on the superior frontal and precentral gyrus bilaterally. Further laminar thickness deficits were observed in the bilateral orbitofrontal cortex and medial occipital cortex. The deficits in the cortical surface were especially pronounced in the child sample, while adult patients showed a more typical laminar thickness across the cerebral mantle. These findings show that the neuroanatomical profile of ADHD, especially the childhood form of the disorder, involves robust alterations in the cortical mantle, which are most prominent in brain regions subserving attentional processing.

Effects of laminar separation bubbles and turbulent separation on airfoil stall

Energy Technology Data Exchange (ETDEWEB)

Dini, P. [Carleton College, Northfield, MN (United States); Coiro, D.P. [Universita di Napoli (Italy)

1997-12-31

An existing two-dimensional, interactive, stall prediction program is extended by improving its laminar separation bubble model. The program now accounts correctly for the effects of the bubble on airfoil performance characteristics when it forms at the mid-chord and on the leading edge. Furthermore, the model can now predict bubble bursting on very sharp leading edges at high angles of attack. The details of the model are discussed in depth. Comparisons of the predicted stall and post-stall pressure distributions show excellent agreement with experimental measurements for several different airfoils at different Reynolds numbers.

Ancillary services and the integration of substantial quantities of wind power

DEFF Research Database (Denmark)

Østergaard, Poul Alberg

2006-01-01

. Ballerup: Elkraft System; 2004]. At the same time, Denmark has other forms of distributed generation, e.g., extensive cogeneration of heat and power (CHP) plants for district heating or for covering industrial heat demands. This results in a high fuel-efficiency but also in a technically complex energy......Denmark has the World’s highest penetration of grid connected wind power in electricity generation with a share of 15.0% of total domestic demand in 2002 [Danish Energy Authority. Rapport fra arbejdsgruppen om kraftvarme- og VE-elektricitet. Bilagsrapport. Copenhagen: Danish Energy Authority; 2001...... as the potential impact of heat pumps used for district heating and installed for integration purposes. The analyses are made with particular focus on grid stability and delivery of ancillary services (required to control voltage and frequency) and demonstrate that it is possible to accommodate 50% or more wind...

On combining multi-normalization and ancillary measures for the optimal score level fusion of fingerprint and voice biometrics

Science.gov (United States)

Mohammed Anzar, Sharafudeen Thaha; Sathidevi, Puthumangalathu Savithri

2014-12-01

In this paper, we have considered the utility of multi-normalization and ancillary measures, for the optimal score level fusion of fingerprint and voice biometrics. An efficient matching score preprocessing technique based on multi-normalization is employed for improving the performance of the multimodal system, under various noise conditions. Ancillary measures derived from the feature space and the score space are used in addition to the matching score vectors, for weighing the modalities, based on their relative degradation. Reliability (dispersion) and the separability (inter-/intra-class distance and d-prime statistics) measures under various noise conditions are estimated from the individual modalities, during the training/validation stage. The `best integration weights' are then computed by algebraically combining these measures using the weighted sum rule. The computed integration weights are then optimized against the recognition accuracy using techniques such as grid search, genetic algorithm and particle swarm optimization. The experimental results show that, the proposed biometric solution leads to considerable improvement in the recognition performance even under low signal-to-noise ratio (SNR) conditions and reduces the false acceptance rate (FAR) and false rejection rate (FRR), making the system useful for security as well as forensic applications.

Estimation of electrode location in a rat motor cortex by laminar analysis of electrophysiology and intracortical electrical stimulation

Science.gov (United States)

Yazdan-Shahmorad, A.; Lehmkuhle, M. J.; Gage, G. J.; Marzullo, T. C.; Parikh, H.; Miriani, R. M.; Kipke, D. R.

2011-08-01

While the development of microelectrode arrays has enabled access to disparate regions of a cortex for neurorehabilitation, neuroprosthetic and basic neuroscience research, accurate interpretation of the signals and manipulation of the cortical neurons depend upon the anatomical placement of the electrode arrays in a layered cortex. Toward this end, this report compares two in vivo methods for identifying the placement of electrodes in a linear array spaced 100 µm apart based on in situ laminar analysis of (1) ketamine-xylazine-induced field potential oscillations in a rat motor cortex and (2) an intracortical electrical stimulation-induced movement threshold. The first method is based on finding the polarity reversal in laminar oscillations which is reported to appear at the transition between layers IV and V in laminar 'high voltage spindles' of the rat cortical column. Analysis of histological images in our dataset indicates that polarity reversal is detected 150.1 ± 104.2 µm below the start of layer V. The second method compares the intracortical microstimulation currents that elicit a physical movement for anodic versus cathodic stimulation. It is based on the hypothesis that neural elements perpendicular to the electrode surface are preferentially excited by anodic stimulation while cathodic stimulation excites those with a direction component parallel to its surface. With this method, we expect to see a change in the stimulation currents that elicits a movement at the beginning of layer V when comparing anodic versus cathodic stimulation as the upper cortical layers contain neuronal structures that are primarily parallel to the cortical surface and lower layers contain structures that are primarily perpendicular. Using this method, there was a 78.7 ± 68 µm offset in the estimate of the depth of the start of layer V. The polarity reversal method estimates the beginning of layer V within ±90 µm with 95% confidence and the intracortical stimulation

Photocatalytic Conversion of CO2 to CO using Rhenium Bipyridine Platforms Containing Ancillary Phenyl or BODIPY Moieties

Science.gov (United States)

Andrade, Gabriel A.; Pistner, Allen J.; Yap, Glenn P.A.; Lutterman, Daniel A.; Rosenthal, Joel

2013-01-01

Harnessing of solar energy to drive the reduction of carbon dioxide to fuels requires the development of efficient catalysts that absorb sunlight. In this work, we detail the synthesis, electrochemistry and photophysical properties of a set of homologous fac-ReI(CO)3 complexes containing either an ancillary phenyl (8) or BODIPY (12) substituent. These studies demonstrate that both the electronic properties of the rhenium center and BODIPY chromophore are maintained for these complexes. Photolysis studies demonstrate that both assemblies 8 and 12 are competent catalysts for the photochemical reduction of CO2 to CO in DMF using triethanolamine (TEOA) as a sacrificial reductant. Both compounds 8 and 12 display TOFs for photocatalytic CO production upon irradiation with light (λex ≥ 400 nm) of ~5 hr−1 with TON values of approximately 20. Although structural and photophysical measurements demonstrate that electronic coupling between the BODIPY and fac-ReI(CO)3 units is limited for complex 12, this work clearly shows that the photoactive BODIPY moiety is tolerated during catalysis and does not interfere with the observed photochemistry. When taken together, these results provide a clear roadmap for the development of advanced rhenium bipyridine complexes bearing ancillary BODIPY groups for the efficient photocatalytic reduction of CO2 using visible light. PMID:24015374

Leading edge effect in laminar boundary layer excitation by sound

International Nuclear Information System (INIS)

Leehey, P.; Shapiro, P.

1980-01-01

Essentially plane pure tone sound waves were directed downstream over a heavily damped smooth flat plate installed in a low turbulence (0.04%) subsonic wind tunnel. Laminar boundary layer disturbance growth rates were measured with and without sound excitation and compared with numerical results from spatial stability theory. The data indicate that the sound field and Tollmien-Schlichting (T-S) waves coexist with comparable amplitudes when the latter are damped; moreover, the response is linear. Higher early growth rates occur for excitation by sound than by stream turbulence. Theoretical considerations indicate that the boundary layer is receptive to sound excitation primarily at the test plate leading edge. (orig.)

Comparative in-flight and wind tunnel investigation of the development of natural and controlled disturbances in the laminar boundary layer of an airfoil

Energy Technology Data Exchange (ETDEWEB)

Peltzer, Inken [Technical University of Berlin, Institute for Aeronautics and Astronautics, Berlin (Germany)

2008-06-15

This paper describes in-flight and wind tunnel research into laminar-turbulent transition. Measurements were carried out with a laminar wing glove for a glider (Twin II Grob G103), which could also be used in the large laminar wind tunnel at the Institute for Aerodynamics and Gasdynamics in Stuttgart. The central aspect of the investigation was the survey of the temporal-spatial development and propagation of natural as well as controlled generated waves. For the experiments performed, varied sensor arrays were used which allowed the two-dimensional acquisition of flow information on the glove (surface hot-wire and piezo foil sensors). Thus the amplification and the spatial distribution of the disturbances could be measured and compared in flight as well as in the wind tunnel, beginning with the very early linear amplification stage to the early non-linear stage of transition. For the investigation of controlled transition, multiple spanwise adjacent harmonic point sources were used which were operated independently. (orig.)

Membraneless laminar flow cell for electrocatalytic CO2 reduction with liquid product separation

International Nuclear Information System (INIS)

Monroe, Morgan M; Lobaccaro, Peter; Lum, Yanwei; Ager, Joel W

2017-01-01

The production of liquid fuel products via electrochemical reduction of CO 2 is a potential path to produce sustainable fuels. However, to be practical, a separation strategy is required to isolate the fuel-containing electrolyte produced at the cathode from the anode and also prevent the oxidation products (i.e. O 2 ) from reaching the cathode. Ion-conducting membranes have been applied in CO 2 reduction reactors to achieve this separation, but they represent an efficiency loss and can be permeable to some product species. An alternative membraneless approach is developed here to maintain product separation through the use of a laminar flow cell. Computational modelling shows that near-unity separation efficiencies are possible at current densities achievable now with metal cathodes via optimization of the spacing between the electrodes and the electrolyte flow rate. Laminar flow reactor prototypes were fabricated with a range of channel widths by 3D printing. CO 2 reduction to formic acid on Sn electrodes was used as the liquid product forming reaction, and the separation efficiency for the dissolved product was evaluated with high performance liquid chromatography. Trends in product separation efficiency with channel width and flow rate were in qualitative agreement with the model, but the separation efficiency was lower, with a maximum value of 90% achieved. (paper)

Osborne Reynolds pipe flow: direct numerical simulation from laminar to fully-developed turbulence

Science.gov (United States)

Adrian, R. J.; Wu, X.; Moin, P.; Baltzer, J. R.

2014-11-01

Osborne Reynolds' pipe experiment marked the onset of modern viscous flow research, yet the detailed mechanism carrying the laminar state to fully-developed turbulence has been quite elusive, despite notable progress related to dynamic edge-state theory. Here, we continue our direct numerical simulation study on this problem using a 250R long, spatially-developing pipe configuration with various Reynolds numbers, inflow disturbances, and inlet base flow states. For the inlet base flow, both fully-developed laminar profile and the uniform plug profile are considered. Inlet disturbances consist of rings of turbulence of different width and radial location. In all the six cases examined so far, energy norms show exponential growth with axial distance until transition after an initial decay near the inlet. Skin-friction overshoots the Moody's correlation in most, but not all, the cases. Another common theme is that lambda vortices amplified out of susceptible elements in the inlet disturbances trigger rapidly growing hairpin packets at random locations and times, after which infant turbulent spots appear. Mature turbulent spots in the pipe transition are actually tight concentrations of hairpin packets looking like a hairpin forest. The plug flow inlet profile requires much stronger disturbances to transition than the parabolic profile.

Effect of mobile laminar airflow units on airborne bacterial contamination during neurosurgical procedures.

Science.gov (United States)

von Vogelsang, A-C; Förander, P; Arvidsson, M; Löwenhielm, P

2018-03-24

Surgical site infections (SSIs) after neurosurgery are potentially life-threatening and entail great costs. SSIs may occur from airborne bacteria in the operating room, and ultraclean air is desired during infection-prone cleaning procedures. Door openings and the number of persons present in the operating room affect the air quality. Mobile laminar airflow (MLAF) units, with horizontal laminar airflow, have previously been shown to reduce airborne bacterial contamination. To assess the effect of MLAF units on airborne bacterial contamination during neurosurgical procedures. In a quasi-experimental design, bacteria-carrying particles (colony-forming units: cfu) during neurosurgical procedures were measured with active air-sampling in operating rooms with conventional turbulent ventilation, and with additional MLAF units. The MLAF units were shifted between operating rooms monthly. Colony-forming unit count and bacterial species detection were conducted after incubation. Data was collected for a period of 18 months. A total of 233 samples were collected during 45 neurosurgical procedures. The use of MLAF units significantly reduced the numbers of cfu in the surgical site area (P neurosurgery to ultraclean air levels. MLAF units are valuable when the main operating room ventilation system is unable to produce ultraclean air in infection-prone clean neurosurgery. Copyright © 2018 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Computer simulations of magnetic fluids in laminar pipe flows

International Nuclear Information System (INIS)

Ramos, D.M.; Cunha, F.R.; Sobral, Y.D.; Fontoura Rodrigues, J.L.A.

2005-01-01

Finite volume method is adapted to simulate momentum and magnetic coupled equations of a laminar magnetic fluid flow. An evolution equation is used to calculate the fluid magnetization. Pressure-driven flow under steady and oscillatory magnetic field is investigated. The magnetostatic limit of the Maxwell's equations is treated in terms of a Poisson equation numerically integrated. The SIMPLE algorithm is used to calculate the pressure-velocity coupling when the pressure field is not prescribed. Suitable boundary conditions for velocity, magnetization and field intensity on the pipe wall are described. Results are obtained for velocity and pressure response under several conditions of the identified physical parameters of the flow. The simulations are verified by comparing numerical results and asymptotic theory, and they show a very good agreement

Laminar forced convection in a cylindrical collinear ohmic sterilizer

Directory of Open Access Journals (Sweden)

Pesso Tommaso

2017-01-01

Full Text Available The present work deals with a thermo-fluid analysis of a collinear cylindrical ohmic heater in laminar flow. The geometry of interest is a circular electrically insulated glass pipe with two electrodes at the pipe ends. For this application, since the electrical conductivity of a liquid food depends strongly on the temperature, the thermal analysis of an ohmic heater requires the simultaneous solution of the electric and thermal fields. In the present work the analysis involves decoupling the previous fields by means of an iterative procedure. The thermal field has been calculated using an analytical solution, which leads to fast calculations for the temperature distribution in the heater. Some considerations of practical interest for the design are also given.

Characteristics of autoignited laminar lifted flames in heated coflow jets of carbon monoxide/hydrogen mixtures

KAUST Repository

Choi, Byungchul

2012-06-01

The characteristics of autoignited lifted flames in laminar jets of carbon monoxide/hydrogen fuels have been investigated experimentally in heated coflow air. In result, as the jet velocity increased, the blowoff was directly occurred from the nozzle-attached flame without experiencing a stabilized lifted flame, in the non-autoignited regime. In the autoignited regime, the autoignited lifted flame of carbon monoxide diluted by nitrogen was affected by the water vapor content in the compressed air oxidizer, as evidenced by the variation of the ignition delay time estimated by numerical calculation. In particular, in the autoignition regime at low temperatures with added hydrogen, the liftoff height of the autoignited lifted flames decreased and then increased as the jet velocity increased. Based on the mechanism in which the autoignited laminar lifted flame is stabilized by ignition delay time, the liftoff height can be influenced not only by the heat loss, but also by the preferential diffusion between momentum and mass diffusion in fuel jets during the autoignition process. © 2012 The Korean Society of Mechanical Engineers.

Coupling of conduction with laminar free convection from a vertical flat plate - an experimental study

Energy Technology Data Exchange (ETDEWEB)

Aharon, J; Lahav, C [Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev; Kalman, H; Shai, I [Ben-Gurion Univ. of the Negev, Beersheba (Israel) Dept, of Mechanical engineering, Pearlstone Center for Aeronautical Engineering Studies

1996-12-01

The present work deals with natural convection on a vertical flat plate, where one side of the plate is maintained at a uniform temperature - T{sub a}, and the other side of the plate is exposed to an environment of constant temperature -T{infinity}. The plate is consisted of several layers of conductive and non-conductive materials such that the series thermal resistance can be expressed as an equivalent heat transfer coefficient h{sub eq} 1/{Sigma}(k{sub i}/d{sub i}). It is also assumed a negligible axial conduction, which can be neglected. The present investigation treats the heat transfer problem in the laminar zone in air (P{sub r}{approx}1). The wall effective heat transfer coefficient is in the range of 4.3 to 11.5 W/m{sup 2} - deg C. An experimental apparatus was constructed to confirm the heat transfer features predicted analytically in a previous work. The local experimental Nusselt number was correlated with the modified Rayleigh number, for the laminar range (authors).

Profile of Hashimoto's Thyroiditis in Sri Lankans: Is There an Increased Risk of Ancillary Pathologies in Hashimoto's Thyroiditis?

OpenAIRE

Siriweera, Eranga Himalee; Ratnatunga, Neelakanthi Vajira Illangakoon

2010-01-01

Hashimoto's thyroiditis has been reported to be associated with many neoplastic and nonneoplastic thyroid pathologies. This retrospective study aims to determine the demographic profile of Hashimoto's thyroiditis in Sri Lankans, document ancillary pathologies in Hashimoto's thyroiditis, and determine whether there is an increased risk of occurrence of malignancies, benign neoplasms, and nonneoplastic benign lesions in Hashimoto's thyroiditis by comparing with thyroids showing multinodular goi...

Numerical solution of inviscid and viscous laminar and turbulent flow around the airfoil

Directory of Open Access Journals (Sweden)

Slouka Martin

2016-01-01

Full Text Available This work deals with the 2D numerical solution of inviscid compressible flow and viscous compressible laminar and turbulent flow around the profile. In a case of turbulent flow algebraic Baldwin-Lomax model is used and compared with Wilcox k-omega model. Calculations are done for NACA 0012 and RAE 2822 airfoil profile for the different angles of upstream flow. Numerical results are compared and discussed with experimental data.

Development of advanced stability theory suction prediction techniques for laminar flow control. [on swept wings

Science.gov (United States)

Srokowski, A. J.

1978-01-01

The problem of obtaining accurate estimates of suction requirements on swept laminar flow control wings was discussed. A fast accurate computer code developed to predict suction requirements by integrating disturbance amplification rates was described. Assumptions and approximations used in the present computer code are examined in light of flow conditions on the swept wing which may limit their validity.

NUMERICAL STUDY OF DEVELOPING LAMINAR FORCED CONVECTION OF A NANOFLUID HEAT TRANSFER IN AN ANNULAR HORIZONTAL PIPE

Directory of Open Access Journals (Sweden)

M BENKHEDDA

2014-12-01

Full Text Available This study reports numerical simulation for 3D laminar forced convection of a nanofluid flow in horizontal annulus with constant heat flux at the outer cylinder will the inner cylinder is considered adiabatic. The numerical model is carried out by solving the governing equation of continuity, momentum and energy using take account for thee finite volume method, with the assistance of SIMPLER algorithm. The results shows that for the Reynolds numbers and Prandtl fixed, the dimensionless velocity profile for the laminar forced convection of a nanofluid consisting of water does not vary with the volume concentration of nanoparticles while the effect of the concentration of nanoparticles on the temperature of the mass is significant nanofluid. These results are consistent with those found in the literature. In general the use of nanofluid with a volume concentration of nanoparticles causes a increase in the coefficient of heat transfer by convection.

Ruthenium cluster-like chalcogenide as a methanol tolerant cathode catalyst in air-breathing laminar flow fuel cells

International Nuclear Information System (INIS)

Whipple, Devin T.; Jayashree, Ranga S.; Egas, Daniela; Alonso-Vante, Nicolas; Kenis, Paul J.A.

2009-01-01

This paper reports the incorporation of a cluster-like Ru x Se y as a methanol tolerant cathode catalyst in a laminar flow fuel cell. The effect on cell performance of several concentrations of methanol in the cathode stream was investigated for the Ru x Se y catalyst and compared to a conventional platinum catalyst. While the Pt catalyst exhibited up to ∼80% drop in power density, the Ru x Se y catalyst showed no decrease in performance when the cathode was exposed to methanol. At several methanol concentrations the Ru x Se y catalyst performed better than the Pt catalyst. This demonstration of a methanol tolerant catalyst in a laminar flow fuel cell opens up the way for further miniaturization of the cell design and simplification of its operation as the need for an electrolyte stream to prevent fuel crossover has been eliminated.

System design specification for the 1/4-scale tank and ancillary equipment

International Nuclear Information System (INIS)

Bamberger, J.A.; Bates, J.M.; Waters, E.D.; Heimberger, D.T.

1993-09-01

The Fluid Dynamic Test Facility (FDTF) is located in the 336 Building at the 300 Area of the Hanford Site. The FDTF will contain tanks that model the average internal diameter and height of a 3875 m 3 (1-million-gal) double-shell tank at both 1/12- and 1/4-scale, as well as ancillary equipment required to store, mix, and transport waste simulants. Experiments to be conducted in this facility will include investigations of sludge mobilization, slurry uniformity, aerosol generation, sludge washing, and instrumentation development to support start-up of the Hanford Waste Vitrification Project. This facility will also be used to model concepts and mitigating strategies to be used in the resolution of tank safety issues and the retrieval of waste from watch-list tanks

Laminar Burning Velocities of Fuels for Advanced Combustion Engines (FACE) Gasoline and Gasoline Surrogates with and without Ethanol Blending Associated with Octane Rating

KAUST Repository

Mannaa, Ossama

2016-05-04

Laminar burning velocities of fuels for advanced combustion engines (FACE) C gasoline and of several blends of surrogate toluene reference fuels (TRFs) (n-heptane, iso-octane, and toluene mixtures) of the same research octane number are presented. Effects of ethanol addition on laminar flame speed of FACE-C and its surrogate are addressed. Measurements were conducted using a constant volume spherical combustion vessel in the constant pressure, stable flame regime at an initial temperature of 358 K and initial pressures up to 0.6 MPa with the equivalence ratios ranging from 0.8 to 1.6. Comparable values in the laminar burning velocities were measured for the FACE-C gasoline and the proposed surrogate fuel (17.60% n-heptane + 77.40% iso-octane + 5% toluene) over the range of experimental conditions. Sensitivity of flame propagation to total stretch rate effects and thermo-diffusive instability was quantified by determining Markstein length. Two percentages of an oxygenated fuel of ethanol as an additive, namely, 60 vol% and 85 vol% were investigated. The addition of ethanol to FACE-C and its surrogate TRF-1 (17.60% n-heptane + 77.40% iso-octane + 5% toluene) resulted in a relatively similar increase in the laminar burning velocities. The high-pressure measured values of Markstein length for the studied fuels blended with ethanol showed minimal influence of ethanol addition on the flame’s response to stretch rate and thermo-diffusive instability. © 2016 Taylor & Francis.

Laminar Burning Velocities of Fuels for Advanced Combustion Engines (FACE) Gasoline and Gasoline Surrogates with and without Ethanol Blending Associated with Octane Rating

KAUST Repository

Mannaa, Ossama; Mansour, Morkous S.; Roberts, William L.; Chung, Suk-Ho

2016-01-01

Laminar burning velocities of fuels for advanced combustion engines (FACE) C gasoline and of several blends of surrogate toluene reference fuels (TRFs) (n-heptane, iso-octane, and toluene mixtures) of the same research octane number are presented. Effects of ethanol addition on laminar flame speed of FACE-C and its surrogate are addressed. Measurements were conducted using a constant volume spherical combustion vessel in the constant pressure, stable flame regime at an initial temperature of 358 K and initial pressures up to 0.6 MPa with the equivalence ratios ranging from 0.8 to 1.6. Comparable values in the laminar burning velocities were measured for the FACE-C gasoline and the proposed surrogate fuel (17.60% n-heptane + 77.40% iso-octane + 5% toluene) over the range of experimental conditions. Sensitivity of flame propagation to total stretch rate effects and thermo-diffusive instability was quantified by determining Markstein length. Two percentages of an oxygenated fuel of ethanol as an additive, namely, 60 vol% and 85 vol% were investigated. The addition of ethanol to FACE-C and its surrogate TRF-1 (17.60% n-heptane + 77.40% iso-octane + 5% toluene) resulted in a relatively similar increase in the laminar burning velocities. The high-pressure measured values of Markstein length for the studied fuels blended with ethanol showed minimal influence of ethanol addition on the flame’s response to stretch rate and thermo-diffusive instability. © 2016 Taylor & Francis.

Prediction of spatial soil property information from ancillary sensor data using ordinary linear regression: Model derivations, residual assumptions and model validation tests

Science.gov (United States)

Geospatial measurements of ancillary sensor data, such as bulk soil electrical conductivity or remotely sensed imagery data, are commonly used to characterize spatial variation in soil or crop properties. Geostatistical techniques like kriging with external drift or regression kriging are often use...

Cortical laminar necrosis in brain infarcts: serial MRI

Energy Technology Data Exchange (ETDEWEB)

Siskas, N.; Lefkopoulos, A.; Ioannidis, I.; Charitandi, A.; Dimitriadis, A.S. [Radiology Department, AHEPA University Hospital, Aristotele University of Thessaloniki (Greece)

2003-05-01

High-signal cortical lesions are observed on T1-weighted images in cases of brain infarct. Histological examination has demonstrated these to be ''cortical laminar necrosis'', without haemorrhage or calcification. We report serial MRI in this condition in 12 patients with brain infarcts. We looked at high-signal lesions on T1-weighted images, chronological changes in signal intensity and contrast enhancement. High-signal cortical lesions began to appear about 2 weeks after the ictus, were prominent at 1 - 2 months, then became less evident, but occasionally remained for up to 1.5 years. They gave high signal or were isointense on T2-weighted images and did not give low signal at any stage. Contrast enhancement of these lesions was prominent at 1 - 2 months, and less apparent from 3 months, but was seen up to 5 months. (orig.)

Flow instability in laminar jet flames driven by alternating current electric fields

KAUST Repository

Kim, Gyeong Taek

2016-10-13

The effect of electric fields on the instability of laminar nonpremixed jet flames was investigated experimentally by applying the alternating current (AC) to a jet nozzle. We aimed to elucidate the origin of the occurrence of twin-lifted jet flames in laminar jet flow configurations, which occurred when AC electric fields were applied. The results indicated that a twin-lifted jet flame originated from cold jet instability, caused by interactions between negative ions in the jet flow via electron attachment as O +e→O when AC electric fields were applied. This was confirmed by conducting systematic, parametric experiment, which included changing gaseous component in jets and applying different polarity of direct current (DC) to the nozzle. Using two deflection plates installed in parallel with the jet stream, we found that only negative DC on the nozzle could charge oxygen molecules negatively. Meanwhile, the cold jet instability occurred only for oxygen-containing jets. A shedding frequency of jet stream due to AC driven instability showed a good correlation with applied AC frequency exhibiting a frequency doubling. However, for the applied AC frequencies over 80Hz, the jet did not respond to the AC, indicating an existence of a minimum flow induction time in a dynamic response of negative ions to external AC fields. Detailed regime of the instability in terms of jet velocity, AC voltage and frequency was presented and discussed. Hypothesized mechanism to explain the instability was also proposed.

Laser-Doppler measurements of laminar and turbulent flow in a pipe bend

Energy Technology Data Exchange (ETDEWEB)

Enayet, M.M.; Gibson, M.M.; Taylor, A.M.K.P.; Yianneskis, M.

1982-12-01

Laser-Doppler measurements are reported for laminar and turbulent flow through a 90/sup 0/ bend of circular cross-section with mean radius of curvature equal to 2.8 times the diameter. The measurements were made in cross-stream planes 0.58 diameters upstream of the bend inlet plane, in 30, 60, and 75/sup 0/ planes in the bend and in planes one and six diameters downstream of the exit plane. Three sets of data were obtained: for laminar flow at Reynolds numbers of 500 and 1093 and for turbulent flow at the maximum obtainable Reynolds number of 43 000. The results show the development of strong pressure-driven secondary flows in the form of a pair of counter-rotating vortices in the streamwise direction. The strength and character of the secondary flows were found to depend on the thickness and nature of the inlet boundary layerd, conditions which could not be varied independently of Reynolds number. The quantitative anemometer measurements are supported by flow visualization studies. Refractive index matching at the fluid-wall interface was not used; the measurements consist, therefore, of streamwise components of mean and fluctuating velocities only, supplemented by wall pressure measurements for the turbulent flow. This displacement of the laser measurement volume due to refraction is allowed for in simple geometrical calculations. The results are intended for use as benchmark data for calibrating flow calculation methods.

F-16XL Ship #2 Laminar Flow Glove mounting

Science.gov (United States)

1995-01-01

NASA's two-seat F-16XL research aircraft is shown in the modification hangar at NASA's Dryden Flight Research Center, Edwards, California, during installation of a titanium 'glove' on the upper surface of its modified left wing. The aircraft subsequently carried out a 13-month-long, 45-flight research program which investigated drawing off a small part of the boundary-layer air in order to provide laminar--or smooth--flow over a major portion of a wing flying at supersonic speeds. A turbo-compressor in the aircraft's fuselage provided suction to draw air through more than 10 million tiny laser-drilled holes in the glove via a manifold system employing 20 valves. Data obtained during the program could assist designers of future aircraft in developing a more efficient high-speed civil transport.

Proportional feedback control of laminar flow over a hemisphere

Energy Technology Data Exchange (ETDEWEB)

Lee, Jung Il [Dept. of Mechanical Engineering, Ajou University, Suwon (Korea, Republic of); Son, Dong Gun [Severe Accident and PHWR Safety Research Division, Korea Atomic Energy Research Institute (KAERI), Daejeon (Korea, Republic of)

2016-08-15

In the present study, we perform a proportional feedback control of laminar flow over a hemisphere at Re = 300 to reduce its lift fluctuations by attenuating the strength of the vortex shedding. As a control input, blowing/suction is distributed on the surface of hemisphere before the separation, and its strength is linearly proportional to the transverse velocity at a sensing location in the centerline of the wake. The sensing location is determined based on a correlation function between the lift force and the time derivative of sensing velocity. The optimal proportional gains for the proportional control are obtained for the sensing locations considered. The present control successfully attenuates the velocity fluctuations at the sensing location and three dimensional vertical structures in the wake, resulting in the reduction of lift fluctuations of hemisphere.

Commercial Building Loads Providing Ancillary Services in PJM

Energy Technology Data Exchange (ETDEWEB)

MacDonald, Jason; Kiliccote, Sila; Boch, Jim; Chen, Jonathan; Nawy, Robert

2014-06-27

The adoption of low carbon energy technologies such as variable renewable energy and electric vehicles, coupled with the efficacy of energy efficiency to reduce traditional base load has increased the uncertainty inherent in the net load shape. Handling this variability with slower, traditional resources leads to inefficient system dispatch, and in some cases may compromise reliability. Grid operators are looking to future energy technologies, such as automated demand response (DR), to provide capacity-based reliability services as the need for these services increase. While DR resources are expected to have the flexibility characteristics operators are looking for, demonstrations are necessary to build confidence in their capabilities. Additionally, building owners are uncertain of the monetary value and operational burden of providing these services. To address this, the present study demonstrates the ability of demand response resources providing two ancillary services in the PJM territory, synchronous reserve and regulation, using an OpenADR 2.0b signaling architecture. The loads under control include HVAC and lighting at a big box retail store and variable frequency fan loads. The study examines performance characteristics of the resource: the speed of response, communications latencies in the architecture, and accuracy of response. It also examines the frequency and duration of events and the value in the marketplace which can be used to examine if the opportunity is sufficient to entice building owners to participate.

Computational thermal-fluid dynamics analysis of the laminar flow regime in the meander flow geometry characterizing the heat exchanger used in high temperature superconducting current leads

Energy Technology Data Exchange (ETDEWEB)

Rizzo, Enrico, E-mail: enrico.rizzo@kit.edu [Institute for Technical Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany); Heller, Reinhard [Institute for Technical Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany); Richard, Laura Savoldi; Zanino, Roberto [Dipartimento Energia, Politecnico di Torino, 10129 Torino (Italy)

2013-11-15

Highlights: • The laminar regime in the meander flow geometry has been analysed with a previously validated computational strategy. • Several meander flow geometries as well as flow conditions have been analysed. • A range for the Reynolds number has been defined in which the flow can be considered laminar. • Correlations for the pressure drop and the heat transfer coefficients in the laminar regime have been derived. • A comparison between the computed the experimental pressure drop of the W7-X HTS current lead prototype is presented. -- Abstract: The Karlsruhe Institute of Technology and the Politecnico di Torino have developed and validated a computational thermal-fluid dynamics (CtFD) strategy for the systematic analysis of the thermal-hydraulics inside the meander flow heat exchanger used in high-temperature superconducting current leads for fusion applications. In the recent past, the application of this CtFD technique has shown that some operating conditions occurring in these devices may not reach the turbulent regime region. With that motivation, the CtFD analysis of the helium thermal-fluid dynamics inside different meander flow geometries is extended here to the laminar flow regime. Our first aim is to clarify under which operative conditions the flow regime can be considered laminar and how the pressure drop as well as the heat transfer are related to the geometrical parameters and to the flow conditions. From the results of this analysis, correlations for the pressure drop and for the heat transfer coefficient in the meander flow geometry have been derived, which are applicable with good accuracy to the design of meander flow heat exchangers over a broad range of geometrical parameters.

Computational thermal-fluid dynamics analysis of the laminar flow regime in the meander flow geometry characterizing the heat exchanger used in high temperature superconducting current leads

International Nuclear Information System (INIS)

Rizzo, Enrico; Heller, Reinhard; Richard, Laura Savoldi; Zanino, Roberto

2013-01-01

Highlights: • The laminar regime in the meander flow geometry has been analysed with a previously validated computational strategy. • Several meander flow geometries as well as flow conditions have been analysed. • A range for the Reynolds number has been defined in which the flow can be considered laminar. • Correlations for the pressure drop and the heat transfer coefficients in the laminar regime have been derived. • A comparison between the computed the experimental pressure drop of the W7-X HTS current lead prototype is presented. -- Abstract: The Karlsruhe Institute of Technology and the Politecnico di Torino have developed and validated a computational thermal-fluid dynamics (CtFD) strategy for the systematic analysis of the thermal-hydraulics inside the meander flow heat exchanger used in high-temperature superconducting current leads for fusion applications. In the recent past, the application of this CtFD technique has shown that some operating conditions occurring in these devices may not reach the turbulent regime region. With that motivation, the CtFD analysis of the helium thermal-fluid dynamics inside different meander flow geometries is extended here to the laminar flow regime. Our first aim is to clarify under which operative conditions the flow regime can be considered laminar and how the pressure drop as well as the heat transfer are related to the geometrical parameters and to the flow conditions. From the results of this analysis, correlations for the pressure drop and for the heat transfer coefficient in the meander flow geometry have been derived, which are applicable with good accuracy to the design of meander flow heat exchangers over a broad range of geometrical parameters

From a bundled energy-capacity pricing model to an energy-capacity-ancillary services pricing model

International Nuclear Information System (INIS)

Raineri, Ricardo; Arce, Raul; Rios, Sebastian; Salamanca, Carlos

2008-01-01

In this paper, we extend the Chilean power generation pricing mechanism, with capacity and energy payments, to one where ancillary services (AS), as frequency regulation and voltage control, are explicitly recognized. Adequacy and security attributes of the electric system and the public good characteristics of AS are set within the payment structure to distribute the financing of AS among those who benefit from their provision. The contribution to finance the provision of AS is determined assessing the value assigned to the system security by each agent, following what's an efficient pricing mechanism in the presence of public goods

Opportunities for ice storage to provide ancillary services to power grids incorporating wind turbine generation

Science.gov (United States)

Finley, Christopher

Power generation using wind turbines increases the electrical system balancing, regulation and ramp rate requirements due to the minute to minute variability in wind speed and the difficulty in accurately forecasting wind speeds. The addition of thermal energy storage, such as ice storage, to a building's space cooling equipment increases the operational flexibility of the equipment by allowing the owner to choose when the chiller is run. The ability of the building owner to increase the power demand from the chiller (e.g. make ice) or to decrease the power demand (e.g. melt ice) to provide electrical system ancillary services was evaluated.

Review of hybrid laminar flow control systems

Science.gov (United States)

Krishnan, K. S. G.; Bertram, O.; Seibel, O.

2017-08-01

The aeronautic community always strived for fuel efficient aircraft and presently, the need for ecofriendly aircraft is even more, especially with the tremendous growth of air traffic and growing environmental concerns. Some of the important drivers for such interests include high fuel prices, less emissions requirements, need for more environment friendly aircraft to lessen the global warming effects. Hybrid laminar flow control (HLFC) technology is promising and offers possibility to achieve these goals. This technology was researched for decades for its application in transport aircraft, and it has achieved a new level of maturity towards integration and safety and maintenance aspects. This paper aims to give an overview of HLFC systems research and associated flight tests in the past years both in the US and in Europe. The review makes it possible to distinguish between the successful approaches and the less successful or outdated approaches in HLFC research. Furthermore, the technology status shall try to produce first estimations regarding the mass, power consumption and performance of HLFC systems as well as estimations regarding maintenance requirements and possible subsystem definitions.

On the optimal choice of the laminar medium substance for ultrarelativistic particle transition radiation detectors

International Nuclear Information System (INIS)

Avakian, A.L.; Garibian, G.M.; Yang, C.

1975-01-01

The dependence of the X-ray transition yield in the energy region 10-20keV produced by an ultrarelativistic charged particle in various laminar media on the substance of the plates is investigated in detail. It is shown that in this case beryllium is the most optimal substance. Other energy regions of transition radiation quanta are also considered. (Auth.)

Optimal bidding strategy for microgrids in joint energy and ancillary service markets considering flexible ramping products

International Nuclear Information System (INIS)

Wang, Jianxiao; Zhong, Haiwang; Tang, Wenyuan; Rajagopal, Ram; Xia, Qing; Kang, Chongqing; Wang, Yi

2017-01-01

Highlights: •Flexible ramping products are modelled in the framework of a microgrid. •Microgrids’ optimal bidding model is proposed in energy and ancillary service markets. •A hybrid stochastic and robust optimization approach is adopted. •The effectiveness of the proposed bidding model is verified based on real-world data. -- Abstract: Due to the volatile nature of wind and photovoltaic power, wind farms and solar stations are generally thought of as the consumers of ramping services. However, a microgrid (MG) is able to strategically integrate various distributed energy resources (DERs) to provide both energy and ancillary services (ASs) for the bulk power system. To evaluate the ramping capabilities of an MG in the joint energy and AS markets, an optimal bidding strategy is developed in this paper considering flexible ramping products (FRPs). By aggregating and coordinating various DERs, including wind turbines (WTs), photovoltaic systems (PVs), micro-turbines (MTs) and energy storage systems (ESSs), the MG is able to optimally allocate the capacities for energy, spinning reserve and ramping. Taking advantage of the synergy among DERs, the MG can maximize its revenues from different markets. Moreover, the flexibility of the MG for the bulk power system can be fully explored. To address the uncertainties introduced by renewable generation and market prices, a hybrid stochastic/robust optimization (RO) approach is adopted. Case studies based on a real-world MG with various DERs demonstrate the market behavior of the MG using the proposed bidding model.

Materiales composites micro- y nano-estructurados basados en hidróxidos dobles laminares de tipo hidrotalcita y silicatos de la familia de las arcillas.

OpenAIRE

Aranda, Pilar; Gómez Avilés, Almudena; Ruiz-Hitzky, Eduardo

2008-01-01

Materiales composites micro- y nano-estructurados basados en hidróxidos dobles laminares de tipo hidrotalcita y silicatos de la familia de las arcillas. La presente invención se refiere a materiales composites micro- o nano-estructurados basados en hidróxidos dobles laminares de tipo hidrotalcita y silicatos de la familia de las arcillas. La invención también se refiere al procedimiento de preparación de estos materiales así como a su uso en aplicaciones diversas tales...

AEROSOL NUCLEATION AND GROWTH DURING LAMINAR TUBE FLOW: MAXIMUM SATURATIONS AND NUCLEATION RATES. (R827354C008)

Science.gov (United States)

An approximate method of estimating the maximum saturation, the nucleation rate, and the total number nucleated per second during the laminar flow of a hot vapour–gas mixture along a tube with cold walls is described. The basis of the approach is that the temperature an...

Laminar burning velocities of near-flammability-limit H2-air-steam mixtures

International Nuclear Information System (INIS)

Loesel Sitar, J.V.; Chan, C.K.; Torchia, F.; Guerrero, A.

1995-01-01

Laminar burning velocities of lean H 2 -air-steam mixtures near the flammability limit were measured by using the pressure-time history of an expanding flame kernel. Although flames in these mixtures are inherently unstable, this difficulty was avoided by using the early pressure rise of the burn. A comparison of results from that method with burning velocities determined from schlieren photographs of the expanding flame kernel gave good agreement. Despite the difficulties, it is believed that the pressure trace method gives results that are useful in modelling reactor accident scenarios. 8 refs., 4 figs

Simulation of Low Velocity Impact Induced Inter- and Intra-Laminar Damage of Composite Beams Based on XFEM

Science.gov (United States)

Sun, Wei; Guan, Zhidong; Li, Zengshan

2017-12-01

In this paper, the Inter-Fiber Fracture (IFF) criterion of Puck failure theory based on the eXtended Finite Element Method (XFEM) was implemented in ABAQUS code to predict the intra-laminar crack initiation of unidirectional (UD) composite laminate. The transverse crack path in the matrix can be simulated accurately by the presented method. After the crack initiation, the propagation of the crack is simulated by Cohesive Zoom Model (CZM), in which the displacement discontinuities and stress concentration caused by matrix crack is introduced into the finite element (FE) model. Combined with the usage of the enriched element interface, which can be used to simulate the inter-laminar delamination crack, the Low Velocity Impact (LVI) induced damage of UD composite laminate beam with a typical stacking of composite laminates [05/903]S is studied. A complete crack initiation and propagation process was simulated and the numerical results obtained by the XFEM are consistent with the experimental results.

On play and playing.

Science.gov (United States)

Rudan, Dusko

2013-12-01

The paper offers a review of the development of the concept of play and playing. The true beginnings of the development of the theories of play are set as late as in the 19th century. It is difficult to define play as such; it may much more easily be defined through its antipode--work. In the beginning, play used to be connected with education; it was not before Freud's theory of psychoanalysis and Piaget's developmental psychology that the importance of play in a child's development began to be explained in more detail. The paper further tackles the role of play in the adult age. Detailed attention is paid to psychodynamic and psychoanalytic authors, in particular D. W. Winnicott and his understanding of playing in the intermediary (transitional) empirical or experiential space. In other words, playing occupies a space and time of its own. The neuroscientific concept of playing is also tackled, in the connection with development as well.

Identification of Conflicts between Transmission and Distribution System Operators when Acquiring Ancillary Services from Electric Vehicles

DEFF Research Database (Denmark)

Zecchino, Antonio; Knezovic, Katarina; Marinelli, Mattia

2017-01-01

ancillary services from flexible units. The investigation is carried out considering a 3-area power system which allows to take into account local constraints as well as system-wide needs. As outcome, this paper identifies the conflicts from both a theoretical and a practical point of view, by means...... products according to requests coming from both distribution and transmission system operators. The goal of this paper is to provide an identification procedure that is able to detect, identify and catalogue possible conflicts among the involved stakeholders that take place when requesting and/or acquiring...

Molecular Structure Laboratory. Fourier Transform Nuclear Magnetic Resonance (FTNMR) Spectrometer and Ancillary Instrumentation at SUNY Geneseo

Energy Technology Data Exchange (ETDEWEB)

Geiger, David K [State Univ. of New York (SUNY), Geneseo, NY (United States)

2015-12-31

An Agilent 400-MR nuclear magnetic resonance (NMR) spectrometer and ancillary equipment were purchased, which are being used for molecular structure elucidation.  The instrumentation is housed in a pre-existing facility designed specifically for its use. This instrument package is being used to expand the research and educational efforts of the faculty and students at SUNY-Geneseo and is made available to neighboring educational institutions and business concerns.  Funds were also used for training of College personnel, maintenance of the instrumentation, and installation of the equipment.

SU-F-I-72: Evaluation of the Ancillary Lead Shielding for Optimizing Radiation Protection in the Interventional Radiology Department

Energy Technology Data Exchange (ETDEWEB)

Tonkopi, E; Lightfoot, C [Dalhousie University, Queen Elizabeth II Health Sciences Ctr, Halifax, NS (Canada); LeBlanc, E [Queen Elizabeth II Health Sciences Ctr, Halifax, NS (Canada)

2016-06-15

Purpose: The rising complexity of interventional fluoroscopic procedures has resulted in an increase of occupational radiation exposures in the interventional radiology (IR) department. This study assessed the impact of ancillary shielding on optimizing radiation protection for the IR staff. Methods: Scattered radiation measurements were performed in two IR suites equipped with Axiom Artis systems (Siemens Healthcare, Erlangen, Germany) installed in 2006 and 2010. Both rooms had suspended ceiling-mounted lead-acrylic shields of 75×60 cm (Mavig, Munich, Germany) with lead equivalency of 0.5 mm, and under-table drapes of 70×116 cm and 65×70 cm in the newer and the older room respectively. The larger skirt can be wrapped around the table’s corner and in addition the newer suite had two upper shields of 25×55 cm and 25×35 cm. The patient was simulated by 30 cm of acrylic, air kerma rate (AKR) was measured with the 180cc ionization chamber (AccuPro Radcal Corporation, Monrovia, CA, USA) at different positions. The ancillary shields, x-ray tube, image detector, and table height were adjusted by the IR radiologist to simulate various clinical setups. The same exposure parameters were used for all acquisitions. AKR measurements were made at different positions relative to the operator. Results: The AKR measurements demonstrated 91–99% x-ray attenuation by the drapes in both suites. The smaller size of the under-table skirt and absence of the side-drapes in the older room resulted in a 20–50 fold increase of scattered radiation to the operator. The mobile suspended lead-acrylic shield reduced AKR by 90–94% measured at 150–170 cm height. The recommendations were made to replace the smaller under-table skirt and to use the ceiling-mounted shields for all IR procedures. Conclusion: The ancillary shielding may significantly affect radiation exposure to the IR staff. The use of suspended ceiling-mounted shields is especially important for reduction of

Numerical simulation of the laminar hydrogen flame in the presence of a quenching mesh

International Nuclear Information System (INIS)

Kudriakov, S.; Studer, E.; Bin, C.

2011-01-01

Recent studies of J.H. Song et al., and S.Y. Yang et al. have been concentrated on mitigation measures against hydrogen risk. The authors have proposed installation of quenching meshes between compartments or around the essential equipment in order to contain hydrogen flames. Preliminary tests were conducted which demonstrated the possibility of flame extinction using metallic meshes of specific size. Considerable amount of numerical and theoretical work on flame quenching phenomenon has been performed in the second half of the last century and several techniques and models have been proposed to predict the quenching phenomenon of the laminar flame system. Most of these models appreciated the importance of heat loss to the surroundings as a primary cause of extinguishment, in particular, the heat transfer by conduction to the containing wall. The supporting simulations predict flame-quenching structure either between parallel plates (quenching distance) or inside a tube of a certain diameter (quenching diameter). In the present study the flame quenching is investigated assuming the laminar hydrogen flame propagating towards a quenching mesh using two-dimensional configuration and the earlier developed models. It is shown that due to a heat loss to a metallic grid the flame can be quenched numerically. (authors)

Analysis of Low Speed Stall Aerodynamics of a Swept Wing with Laminar Flow Glove

Science.gov (United States)

Bui, Trong T.

2014-01-01

Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

Analysis of Low-Speed Stall Aerodynamics of a Swept Wing with Laminar-Flow Glove

Science.gov (United States)

Bui, Trong T.

2014-01-01

Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

Active flow control of the laminar separation bubble on a plunging airfoil near stall

Science.gov (United States)

Pande, Arth; Agate, Mark; Little, Jesse; Fasel, Hermann

2017-11-01

The effects of small amplitude (A/c = 0.048) high frequency (πfc/U∞ = 0.70) plunging motion on the X-56A airfoil are examined experimentally at Re = 200,000 for 12° angle of attack (CL,MAX = 12.25°) . The purpose of this research is to study the aerodynamic influence of structural motion when the wing is vibrating close to its eigenfrequency near static stall. Specific focus is placed on the laminar separation bubble (LSB) near the leading edge and its control via plasma actuation. In the baseline case, the leading edge bubble bursts during the oscillation cycle causing moment stall. A collaborative computational effort has shown that small amplitude forcing at a frequency that is most amplified by the primary instability of the LSB (FLSB+= 1, Fc+= 52) generates coherent spanwise vortices that entrain freestream momentum, thus reducing separation all while maintaining a laminar flow state. Results (PIV and surface pressure) indicate that a similar control mechanism is effective in the experiments. This is significant given the existence of freestream turbulence in the wind tunnel which has been shown to limit the efficacy of this active flow control technique in a model problem using Direct Numerical Simulation. The implications of these results are discussed.

The ignition delay, laminar flame speed and adiabatic temperature characteristics of n-pentane, n-hexane and n-heptane under O{sub 2}/CO{sub 2} atmosphere

Energy Technology Data Exchange (ETDEWEB)

Zhao, Ran [Huazhong Univ. of Science and Technology, Wuhan (China). State Key Lab. of Coal Combustion; Wuhan Textile Univ. (China). School of Environment and Urban Construction; Liu, Hao; Zhong, Xiaojiao; Wang, Zijian; Jin, Ziqin; Qiu, Jianrong [Huazhong Univ. of Science and Technology, Wuhan (China). State Key Lab. of Coal Combustion; Chen, Yingming [Wuhan Textile Univ. (China). School of Environment and Urban Construction

2013-07-01

Oxy-fuel (O{sub 2}/CO{sub 2}) combustion is one of the several promising new technologies which can realize the integrated control of CO{sub 2}, SO{sub 2}, NO{sub X} and other pollutants. However, when fuels are burned in the high CO{sub 2} concentration environment, the combustion characteristics can be very different from conventional air-fired combustion. Such changes imply that the high CO{sub 2} concentration atmosphere has impacts on the combustion processes. In this paper, the ignition time, laminar flame speed and adiabatic temperature property of C{sub 5} {proportional_to} C{sub 7} n-alkane fuels were studied under both ordinary air atmosphere and O{sub 2}/CO{sub 2} atmospheres over a wide range of CO{sub 2} concentration in the combustion systems. A new unified detailed chemical kinetic model was validated and used to simulate the three liquid hydrocarbon fuel's flame characteristics. Based on the verified model, the influences of various parameters (atmosphere, excess oxygen ratio, O{sub 2} concentration, CO{sub 2} concentration, and alkane type) on the C{sub 5} {proportional_to} C{sub 7} n-alkane's flame characteristics were systematically investigated. It can be concluded that high CO{sub 2} concentration atmosphere has negative effect on n-pentane, n-hexane and n-heptane flame's ignition, laminar flame speed and adiabatic temperature. Besides, this work confirms that high CO{sub 2} concentration atmosphere's chemical effects play a pronounced role on the flame characteristics, especially for the ignition time property.

Subchannel friction factors for rod bundles: laminar flow predictions and their application to turbulent flows

International Nuclear Information System (INIS)

Robinson, D.P.

1979-02-01

For the calculation of friction factors the use of correlations validated for smooth circular tubes along with the duct hydraulic diameter is known to be inappropriate for certain non-circular geometries. In order to test the validity and range of application of such correlations to the subchannels of rod bundles a computer programme has been written for the prediction of subchannel laminar velocity distributions and friction coefficients for fully developed flow. The theoretical basis and development of the programme is described along with comparisons between predictions and existing solutions for some simple geometries. Using the computer programme a wide range of calculations have been carried out for flow sections representing edge, corner and internal subchannels of rod bundles with particular emphasis on those of in-line pin bundle geometries. Where comparison can be made the predicted laminar coefficients are in excellent agreement with existing solutions. Although the approach adopted here could be used as the basis of a model for the subchannel axial friction factor, careful account should be taken of enhanced turbulent momentum transfer in situations where the flow is not unidirectional. (UK)

Potential of vehicle-to-grid ancillary services considering the uncertainties in plug-in electric vehicle availability and service/localization limitations in distribution grids

International Nuclear Information System (INIS)

Sarabi, Siyamak; Davigny, Arnaud; Courtecuisse, Vincent; Riffonneau, Yann; Robyns, Benoît

2016-01-01

Highlights: • The availability uncertainty of PEVs are modelled using Gaussian mixture model. • Interdependency of stochastic variables are modelled using copula function. • V2G bidding capacity is calculated using Free Pattern search optimization method. • Localization limitation is considered for V2G service potential assessment. • Competitive services for fleet of V2G-enabled PEVs are identified using fuzzy sets. - Abstract: The aim of the paper is to propose an approach for statistical assessment of the potential of plug-in electric vehicles (PEV) for vehicle-to-grid (V2G) ancillary services, where it focuses on PEVs doing daily home-work commuting. In this approach, the possible ancillary services (A/S) for each PEV fleet in terms of its available V2G power (AVP) and flexible intervals are identified. The flexible interval is calculated using a powerful stochastic global optimization technique so-called “Free Pattern Search” (FPS). A probabilistic method is also proposed to quantify the impacts of PEV’s availability uncertainty using the Gaussian mixture model (GMM), and interdependency of stochastic variables on AVP of each fleet thanks to a multivariate modeling with Copula function. Each fleet is analyzed based on its aggregated PEV numbers at different level of distribution grid, in order to satisfy the ancillary services localization limitation. A case study using the proposed approach evaluates the real potential in Niort, a city in west of France. In fact, by using the proposed approach an aggregator can analyze the V2G potential of PEVs under its contract.

Tratamento conservador dos hematomas extradurais laminares na infância

Directory of Open Access Journals (Sweden)

Orildo Ciquini Júnior

1992-12-01

Full Text Available Os autores relatam sua experiência com o tratamento conservador de 15 crianças com hematoma extradural (HED laminar traumático. Todas, por ocasião do diagnóstico, apresentavam-se neurologicamente estáveis e sem sinais de herniação intracraniana. Estes HED foram descobertos em períodos de 30 minutos e 5 dias depois do trauma, a maioria estando localizados na região parietal. OHED foi reabsorvido espontaneamente em todos os casos, num período que variou de 2 a 12 dias. Os critérios para seleção destes pacientes e os cuidados com essa modalidade de tratamento do HED são discutidos.

Heat transfer in laminar flow for a finned double - tube

International Nuclear Information System (INIS)

Colle, S.

1977-01-01

An analitical study of the steady-state heat transfer in laminar flow in finned double-tube heat exchangers is presented. The fins are plane, straight and continous, equally spaced and are fixed over the external surface of the inner tube. A constant peripheral temperature distribution is assumed to apply over the inner tube surface and each fin, and a constant peripheral heat flux is assumed to apply over the outer tube surface, while the overall heat flux is suposed to be uniform in the longitudinal direction of the duct. The prediction of the thermal performance of the finned double-tube is made by means of the relationship between the Nusselt number, the boundary conditions and the geometric characteristcs of the duct. (author) [pt

Intron retention in mRNA encoding ancillary subunit of insect voltage-gated sodium channel modulates channel expression, gating regulation and drug sensitivity.

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Céline M Bourdin

Full Text Available Insect voltage-gated sodium (Nav channels are formed by a well-known pore-forming α-subunit encoded by para-like gene and ancillary subunits related to TipE from the mutation "temperature-induced-paralysis locus E." The role of these ancillary subunits in the modulation of biophysical and pharmacological properties of Na(+ currents are not enough documented. The unique neuronal ancillary subunit TipE-homologous protein 1 of Drosophila melanogaster (DmTEH1 strongly enhances the expression of insect Nav channels when heterologously expressed in Xenopus oocytes. Here we report the cloning and functional expression of two neuronal DmTEH1-homologs of the cockroach, Periplaneta americana, PaTEH1A and PaTEH1B, encoded by a single bicistronic gene. In PaTEH1B, the second exon encoding the last 11-amino-acid residues of PaTEH1A is shifted to 3'UTR by the retention of a 96-bp intron-containing coding-message, thus generating a new C-terminal end. We investigated the gating and pharmacological properties of the Drosophila Nav channel variant (DmNav1-1 co-expressed with DmTEH1, PaTEH1A, PaTEH1B or a truncated mutant PaTEH1Δ(270-280 in Xenopus oocytes. PaTEH1B caused a 2.2-fold current density decrease, concomitant with an equivalent α-subunit incorporation decrease in the plasma membrane, compared to PaTEH1A and PaTEH1Δ(270-280. PaTEH1B positively shifted the voltage-dependences of activation and slow inactivation of DmNav1-1 channels to more positive potentials compared to PaTEH1A, suggesting that the C-terminal end of both proteins may influence the function of the voltage-sensor and the pore of Nav channel. Interestingly, our findings showed that the sensitivity of DmNav1-1 channels to lidocaine and to the pyrazoline-type insecticide metabolite DCJW depends on associated TEH1-like subunits. In conclusion, our work demonstrates for the first time that density, gating and pharmacological properties of Nav channels expressed in Xenopus oocytes can be

Approaches to Enable Demand Response by Industrial Loads for Ancillary Services Provision

Science.gov (United States)

Zhang, Xiao

Demand response has gained significant attention in recent years as it demonstrates potentials to enhance the power system's operational flexibility in a cost-effective way. Industrial loads such as aluminum smelters, steel manufacturers, and cement plants demonstrate advantages in supporting power system operation through demand response programs, because of their intensive power consumption, already existing advanced monitoring and control infrastructure, and the strong economic incentive due to the high energy costs. In this thesis, we study approaches to efficiently integrate each of these types of manufacturing processes as demand response resources. The aluminum smelting process is able to change its power consumption both accurately and quickly by controlling the pots' DC voltage, without affecting the production quality. Hence, an aluminum smelter has both the motivation and the ability to participate in demand response. First, we focus on determining the optimal regulation capacity that such a manufacturing plant should provide. Next, we focus on determining its optimal bidding strategy in the day-ahead energy and ancillary services markets. Electric arc furnaces (EAFs) in steel manufacturing consume a large amount of electric energy. However, a steel plant can take advantage of time-based electricity prices by optimally arranging energy-consuming activities to avoid peak hours. We first propose scheduling methods that incorporate the EAFs' flexibilities to reduce the electricity cost. We then propose methods to make the computations more tractable. Finally, we extend the scheduling formulations to enable the provision of spinning reserve. Cement plants are able to quickly adjust their power consumption rate by switching on/off the crushers. However, switching on/off the loading units only achieves discrete power changes, which restricts the load from offering valuable ancillary services such as regulation and load following, as continuous power changes

Friction factors referring to laminar flow through pipe bundles with longitudinal webs

Energy Technology Data Exchange (ETDEWEB)

Schenkel, G

1983-09-01

Pipe bundles with continuous webs or ribs between adjacent pipes, as well as between outer pipes and channel walls, are much more vibrational proof than web-free systems. In addition, the change-over from a multiple-connected web-free cross-section to a set of singly-connected cross-sections facilitates the calculation of friction factors. The investigation is concerned with isothermal steady fully-developed laminar flow of Newtonian fluids. In particularly, pipe bundles with squares and hexagonal arrays in respective channels are treated. Friction factors for the subchannels are taken from a former paper of the author.

Influence of thermal radiation on soot production in Laminar axisymmetric diffusion flames

International Nuclear Information System (INIS)

Demarco, R.; Nmira, F.; Consalvi, J.L.

2013-01-01

The aim of this paper is to study the effect of radiative heat transfer on soot production in laminar axisymmetric diffusion flames. Twenty-four C 1 –C 3 hydrocarbon–air flames, consisting of normal (NDF) and inverse (IDF) diffusion flames at both normal gravity (1 g) and microgravity (0 g), and covering a wide range of conditions affecting radiative heat transfer, were simulated. The numerical model is based on the Steady Laminar Flamelet (SLF) model, a semi-empirical two-equation acetylene/benzene based soot model and the Statistical Narrow Band Correlated K (SNBCK) model coupled to the Finite Volume Method (FVM) to compute thermal radiation. Predictions relative to velocity, temperature, soot volume fraction and radiative losses are on the whole in good agreement with the available experimental data. Model results show that, for all the flames considered, thermal radiation is a crucial process with a view to providing accurate predictions for temperatures and soot concentrations. It becomes increasingly significant from IDFs to NDFs and its influence is much greater as gravity is reduced. The radiative contribution of gas prevails in the weakly-sooting IDFs and in the methane and ethane NDFs, whereas soot radiation dominates in the other flames. However, both contributions are significant in all cases, with the exception of the 1 g IDFs investigated where soot radiation can be ignored. The optically-thin approximation (OTA) was also tested and found to be applicable as long as the optical thickness, based on flame radius and Planck mean absorption coefficient, is less than 0.05. The OTA is reasonable for the IDFs and for most of the 1 g NDFs, but it fails to predict the radiative heat transfer for the 0 g NDFs. The accuracy of radiative-property models was then assessed in the latter cases. Simulations show that the gray approximation can be applied to soot but not to combustion gases. Both the non-gray and gray soot versions of the Full Spectrum Correlated

Numerical analysis of a hypersonic turbulent and laminar flow using a commercial CFD solver

OpenAIRE

Pajčin Miroslav P.; Simonović Aleksandar M.; Ivanov Toni D.; Komarov Dragan M.; Stupar Slobodan N.

2017-01-01

Computational fluid dynamics computations for two hypersonic flow cases using the commercial ANSYS FLUENT 16.2 CFD software were done. In this paper, an internal and external hypersonic flow cases were considered and analysis of the hypersonic flow using different turbulence viscosity models available in ANSYS FLUENT 16.2 as well as the laminar viscosity model were done. The obtained results were after compared and commented upon. [Project of the Serbian Ministry of Education, Science and Tec...

Subchannel and bundle friction factors and flow split parameters for laminar transition and turbulent longitudinal flows in wire wrap spaced hexagonal arrays

International Nuclear Information System (INIS)

Hawley, J.T.; Chiu, C.; Todreas, N.E.; Rohsenow, W.M.

1980-01-01

Correlations are presented for subchannel and bundle friction factors and flowsplit parameters for laminar, transition and turbulent longitudinal flows in wire wrap spaced hexagonal arrays. These results are obtained from pressure drop models of flow in individual subchannels. For turbulent flow, an existing pressure drop model for flow in edge subchannels is extended, and the resulting edge subchannel friction factor is identified. Using the expressions for flowsplit parameters and the equal pressure drops assumption, the interior subchannel and bundle friction factors are obtained. For laminar flow, models are developed for pressure drops of individual subchannels. From these models, expressions for the subchannel friction factors are identified and expressions for the flowsplit parameters are derived

Subchannel and bundle friction factors and flowsplit parameters for laminar, transition, and turbulent longitudinal flows in wire-wrap spaced hexagonal arrays. [LMFBR

Energy Technology Data Exchange (ETDEWEB)

Hawley, J.T.; Chiu, C.; Rohsenow, W.M.; Todreas, N.E.

1980-08-01

Correlations are presented for subchannel and bundle friction factors and flowsplit parameters for laminar, transition and turbulent longitudinal flows in wire wrap spaced hexagonal arrays. These results are obtained from pressure drop models of flow in individual subchannels. For turbulent flow, an existing pressure drop model for flow in edge subchannels is extended, and the resulting edge subchannel friction factor is identified. Using the expressions for flowsplit parameters and the equal pressured drop assumption, the interior subchannel and bundle friction factors are obtained. For laminar flow, models are developed for pressure drops of individual subchannels. From these models, expressions for the subchannel friction factors are identified and expressions for the flowsplit parameters are derived.

Play, Playfulness, Creativity and Innovation

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Patrick Bateson

2014-05-01

Full Text Available Play, as defined by biologists and psychologists, is probably heterogeneous. On the other hand, playfulness may be a unitary motivational state. Playful play as opposed to activities that merge into aggression is characterized by positive mood, intrinsic motivation, occurring in a protected context and easily disrupted by stress. Playful play is a good measure of positive welfare. It can occupy a substantial part of the waking-life of a young mammal or bird. Numerous functions for play have been proposed and they are by no means mutually exclusive, but some evidence indicates that those individual animals that play most are most likely to survive and reproduce. The link of playful play to creativity and hence to innovation in humans is strong. Considerable evidence suggests that coming up with new ideas requires a different mindset from usefully implementing a new idea.

MRI of Retinal Free Radical Production With Laminar Resolution In Vivo

Science.gov (United States)

Berkowitz, Bruce A.; Lewin, Alfred S.; Biswal, Manas R.; Bredell, Bryce X.; Davis, Christopher; Roberts, Robin

2016-01-01

Purpose Recent studies have suggested the hypothesis that quench-assisted 1/T1 magnetic resonance imaging (MRI) measures free radical production with laminar resolution in vivo without the need of a contrast agent. Here, we test this hypothesis further by examining the spatial and detection sensitivity of quench-assisted 1/T1 MRI to strain, age, or retinal cell layer-specific genetic manipulations. Methods We studied: adult wild-type mice; mice at postnatal day 7 (P7); cre dependent retinal pigment epithelium (RPE)-specific MnSOD knockout mice; doxycycline-treated Sod2flox/flox mice lacking the cre transgene; and α-transducin knockout (Gnat1−/−) mice on a C57Bl/6 background. Transretinal 1/T1 profiles were mapped in vivo in the dark without or with antioxidant treatment, or followed by light exposure. We calibrated profiles spatially using optical coherence tomography. Results Dark-adapted RPE-specific MnSOD knockout mice had greater than normal 1/T1 in the RPE and outer nuclear layers that was corrected to wild-type levels by antioxidant treatment. Dark and light Gnat1−/− mice also had greater than normal outer retinal 1/T1 values. In adult wild-type mice, dark values of 1/T1 in the ellipsoid region and in the outer segment were suppressed by 13 minutes of light. By 29 minutes of light, 1/T1 reduction extended to the outer nuclear layer. Gnat1−/− mice demonstrated a faster light-evoked suppression of 1/T1 values in the outer retina. In P7 mice, transretinal 1/T1 profiles were the same in dark and light. Conclusions Quench-assisted MRI has the laminar resolution and detection sensitivity to evaluate normal and pathologic production of free radicals in vivo. PMID:26886890

Engineering evaluation/cost analysis for the 105-DR and 105-F Reactor facilities and ancillary facilities

International Nuclear Information System (INIS)

Coenenberg, E.T.

1998-01-01

This document presents the results of an engineering evaluation/cost analysis (EE/CA) that was conducted to evaluate alternatives to address final disposition of the 105-DR and 105-F Reactor Buildings (subsequently referred to as facilities), including the fuel storage basins (FSB) and below-grade portions of the reactors, excluding the reactor blocks. The reactor blocks will remain in a safe storage mode for up to 75 years as identified in the Record the Decision (ROD) (58 FR 48509) for the Environmental Impact Statement (EIS), Decommissioning of Eight Surplus Production Reactors at the Hanford Site, Richland, Washington (DOE 1992a). This EE/CA also addresses final disposition of four ancillary facilities: 116-D and 116-DR Exhaust Air Stacks, 117-DR Exhaust Filter Building, and 119-DR Exhaust Air Sample Building. The 105-DR and 105-F facilities are located in the 100-D and 100-F Areas of the Hanford Site. In November 1989, the 100 Area of the Hanford Site was placed on the U.S. Environmental Protection Agency's (EPA) National Priorities List (NPL) under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). The 100 Area NPL includes the 100-D Area (which includes the 100-DR site) and the 100-F Area, which are in various stages of the remediation process. It has been determined by DOE that hazardous substances in the 105-DR, 105-F, and the four ancillary facilities may present a potential threat to human health or the environment, and that a non-time critical removal action at these facilities is warranted. To help determine the most appropriate action, DOE, in cooperation with the Washington State Department of Ecology (Ecology) and the EPA, has prepared this EE/CA. The scope of the evaluation includes the 105-DR and 105-F facilities and the four ancillary facilities. The 116-DR and 117-DR facilities are located within the boundaries of the 105-DR Large Sodium Fire Facility Treatment, Storage, and Disposal (TSD) unit, which is

Calculation of pressure gradients from MR velocity data in a laminar flow model

International Nuclear Information System (INIS)

Adler, R.S.; Chenevert, T.L.; Fowlkes, J.B.; Pipe, J.G.; Rubin, J.M.

1990-01-01

This paper reports on the ability of current imaging modalities to provide velocity-distribution data that offers the possibility of noninvasive pressure-gradient determination from an appropriate rheologic model of flow. A simple laminar flow model is considered at low Reynolds number, RE calc = 0.59 + (1.13 x (dp/dz) meas ), R 2 = .994, in units of dyne/cm 2 /cm for the range of flows considered. The authors' results indicate the potential usefulness of noninvasive pressure-gradient determinations from quantitative analysis of imaging-derived velocity data

Selective in situ functionalization of biosensors on LOC devices using laminar co-flow

DEFF Research Database (Denmark)

Parra-Cabrera, C.; Sporer, C.; Rodriguez-Villareal, I.

2012-01-01

Many applications involving lab-on-a-chip (LOC) devices are prevented from entering the market because of difficulties to achieve mass production and impart suitable properties allowing long-term storage. To integrate biosensors on these microfluidic chips, one of the main restrictions...... is the fabrication and stability of the molecular modifications that must be performed on the surfaces of the sensors for a given application. The complexity of the problem increases exponentially when the LOC integrates several of these sensors. Here we present a system based on laminar co-flow to perform an on...

Effects of Burner Configurations on the Natural Oscillation Characteristics of Laminar Jet Diffusion Flames

Directory of Open Access Journals (Sweden)

K. R. V. Manikantachari

2015-09-01

Full Text Available In this work, effects of burner configurations on the natural oscillations of methane laminar diffusion flames under atmospheric pressure and normal gravity conditions have been studied experimentally. Three regimes of laminar diffusion flames, namely, steady, intermittent flickering and continuous flickering have been investigated. Burner configurations such as straight pipe, contoured nozzle and that having an orifice plate at the exit have been considered. All burners have the same area of cross section at the exit and same burner lip thickness. Flame height data has been extracted from direct flame video using MATLAB. Shadowgraph videos have been captured to analyze the plume width characteristics. Results show that, the oscillation characteristics of the orifice burner is significantly different from the other two burners; orifice burner produces a shorter flame and wider thermal plume width in the steady flame regime and the onset of the oscillation/flickering regimes for the orifice burner occurs at a higher fuel flow rate. In the natural flickering regime, the dominating frequency of flame flickering remains within a small range, 12.5 Hz to 15 Hz, for all the burners and for all fuel flow rates. The time-averaged flame length-scale parameters, such as the maximum and the minimum flame heights, increase with respect to the fuel flow rate, however, the difference in the maximum and the minimum flame heights remains almost constant.

Dynamic bioprocessing and microfluidic transport control with smart magnetic nanoparticles in laminar-flow devices.

Science.gov (United States)

Lai, James J; Nelson, Kjell E; Nash, Michael A; Hoffman, Allan S; Yager, Paul; Stayton, Patrick S

2009-07-21

In the absence of applied forces, the transport of molecules and particulate reagents across laminar flowstreams in microfluidic devices is dominated by the diffusivities of the transported species. While the differential diffusional properties between smaller and larger diagnostic targets and reagents have been exploited for bioseparation and assay applications, there are limitations to methods that depend on these intrinsic size differences. Here a new strategy is described for exploiting the sharply reversible change in size and magnetophoretic mobility of "smart" magnetic nanoparticles (mNPs) to perform bioseparation and target isolation under continuous flow processing conditions. The isolated 5 nm mNPs do not exhibit significant magnetophoretic velocities, but do exhibit high magnetophoretic velocities when aggregated by the action of a pH-responsive polymer coating. A simple external magnet is used to magnetophorese the aggregated mNPs that have captured a diagnostic target from a lower pH laminar flowstream (pH 7.3) to a second higher pH flowstream (pH 8.4) that induces rapid mNP disaggregation. In this second dis-aggregated state and flowstream, the mNPs continue to flow past the magnet rather than being immobilized at the channel surface near the magnet. This stimuli-responsive reagent system has been shown to transfer 81% of a model protein target from an input flowstream to a second flowstream in a continuous flow H-filter device.

Numerical and Experimental Investigation of Computed Tomography of Chemiluminescence for Hydrogen-Air Premixed Laminar Flames

Directory of Open Access Journals (Sweden)

Liang Lv

2016-01-01

Full Text Available Computed tomography of chemiluminescence (CTC is a promising technique for combustion diagnostics, providing instantaneous 3D information of flame structures, especially in harsh circumstance. This work focuses on assessing the feasibility of CTC and investigating structures of hydrogen-air premixed laminar flames using CTC. A numerical phantom study was performed to assess the accuracy of the reconstruction algorithm. A well-designed burner was used to generate stable hydrogen-air premixed laminar flames. The OH⁎ chemiluminescence intensity field reconstructed from 37 views using CTC was compared to the OH⁎ chemiluminescence distributions recorded directly by a single ICCD camera from the side view. The flame structures in different flow velocities and equivalence ratios were analyzed using the reconstructions. The results show that the CTC technique can effectively indicate real distributions of the flame chemiluminescence. The height of the flame becomes larger with increasing flow velocities, whereas it decreases with increasing equivalence ratios (no larger than 1. The increasing flow velocities gradually lift the flame reaction zones. A critical cone angle of 4.76 degrees is obtained to avoid blow-off. These results set up a foundation for next studies and the methods can be further developed to reconstruct 3D structures of flames.

The Role of Molecule Clustering by Hydrogen Bond in Hydrous Ethanol on Laminar Burning Velocity

Directory of Open Access Journals (Sweden)

I Made Suarta

2016-01-01

Full Text Available The role of hydrogen bond molecule clustering in laminar burning velocities was observed. The water in hydrous ethanol can change the interaction between water-ethanol molecules. A certain amount of water can become oxygenated which increases the burning velocity. The hydrogen bond interaction pattern of ethanol and water molecules was modeled. Based on the molecular model, azeotropic behavior emerges from ethanol-water hydrogen bond, which is at a 95.1%v composition. The interaction with water molecule causes the ethanol molecule to be clustered with centered oxygenated compound. So, it supplies extra oxygen and provides intermolecular empty spaces that are easily infiltrated by the air. In the azeotropic composition, the molecular bond chain is the shortest, so hypothetically the burning velocity is anticipated to increase. The laminar burning velocity of ethanol fuel was tested in a cylindrical explosion bomb in lean, stoichiometric, and rich mixtures. The experimental result showed that the maximum burning velocity occurred at hydrous ethanol of 95.5%v composition. This discrepancy is the result of the addition of energy from 7.7% free ethanol molecules that are not clustered. At the rich mixture, the burning velocity of this composition is higher than that of anhydrous ethanol.

Sequence of neuron origin and neocortical laminar fate: relation to cell cycle of origin in the developing murine cerebral wall

Science.gov (United States)

Takahashi, T.; Goto, T.; Miyama, S.; Nowakowski, R. S.; Caviness, V. S. Jr

1999-01-01

Neurons destined for each region of the neocortex are known to arise approximately in an "inside-to-outside" sequence from a pseudostratified ventricular epithelium (PVE). This sequence is initiated rostrolaterally and propagates caudomedially. Moreover, independently of location in the PVE, the neuronogenetic sequence in mouse is divisible into 11 cell cycles that occur over a 6 d period. Here we use a novel "birth hour" method that identifies small cohorts of neurons born during a single 2 hr period, i.e., 10-20% of a single cell cycle, which corresponds to approximately 1.5% of the 6 d neuronogenetic period. This method shows that neurons arising with the same cycle of the 11 cycle sequence in mouse have common laminar fates even if they arise from widely separated positions on the PVE (neurons of fields 1 and 40) and therefore arise at different embryonic times. Even at this high level of temporal resolution, simultaneously arising cells occupy more than one cortical layer, and there is substantial overlap in the distributions of cells arising with successive cycles. We demonstrate additionally that the laminar representation of cells arising with a given cycle is little if at all modified over the early postnatal interval of histogenetic cell death. We infer from these findings that cell cycle is a neuronogenetic counting mechanism and that this counting mechanism is integral to subsequent processes that determine cortical laminar fate.

Viscoelasticidad lineal de la fase líquido-cristalina laminar de un sistema tensioactivo no iónico/hidrocarburo/agua

Directory of Open Access Journals (Sweden)

Gallegos, C.

2000-08-01

Full Text Available A linear viscoelastic characterization by small amplitude oscillatory shear tests was carried out for heptane/polyoxyethylene glycol nonylphenyl ether (EOa=10/water system exhibiting a lamellar liquid crystalline structure. The influence of composition on the dynamic functions was considered. The lamellar liquid crystalline phase shows a small linear viscoelastic range. The relaxation spectrum of the lamellar liquid crystalline phase presents two regions: the transition region and the plateau region, characteristic of highly structured systems. The maximum values of the plateau modulus correspond to the systems of intermediate compositions within the realm of existence of the lamellar mesophase.En este estudio se ha caracterizado la respuesta viscoelástica lineal, en cizalla oscilatoria, de la fase líquido-cristalina laminar de sistemas alcohol polietoxilado/heptano/agua, estableciendo las influencias de los distintos componentes en la evolución de las funciones viscoelásticas dinámicas. De los resultados obtenidos puede concluirse que la fase líquido-cristalina laminar se caracteriza por presentar un pequeño intervalo viscoelástico lineal; su espectro de relajación muestra, fundamentalmente, dos regiones, la región de transición y la región plateau, siendo esta última característica de sistemas altamente estructurados; el módulo plateau presenta valores máximos para sistemas con concentraciones intermedias de tensioactivo y heptano dentro del intervalo de existencia de la fase laminar.

Analyzing dendritic growth in a population of immature neurons in the adult dentate gyrus using laminar quantification of disjointed dendrites

Directory of Open Access Journals (Sweden)

Shira eRosenzweig

2011-03-01

Full Text Available In the dentate gyrus of the hippocampus, new granule neurons are continuously produced throughout adult life. A prerequisite for the successful synaptic integration of these neurons is the sprouting and extension of dendrites into the molecular layer of the dentate gyrus. Thus, studies aimed at investigating the developmental stages of adult neurogenesis often use dendritic growth as an important indicator of neuronal health and maturity. Based on the known topography of the dentate gyrus, characterized by distinct laminar arrangement of granule neurons and their extensions, we have developed a new method for analysis of dendritic growth in immature adult-born granule neurons. The method is comprised of laminar quantification of cell bodies, primary, secondary and tertiary dendrites separately and independently from each other. In contrast to most existing methods, laminar quantification of dendrites does not require the use of exogenous markers and does not involve arbitrary selection of individual neurons. The new method relies on immonuhistochemical detection of endogenous markers such as doublecortin to perform a comprehensive analysis of a sub-population of immature neurons. Disjointed, orphan dendrites that often appear in the thin histological sections are taken into account. Using several experimental groups of rats and mice, we demonstrate here the suitable techniques for quantifying neurons and dendrites, and explain how the ratios between the quantified values can be used in a comparative analysis to indicate variations in dendritic growth and complexity.

An Experimental Study of Energy Consumption in Buildings Providing Ancillary Services

Energy Technology Data Exchange (ETDEWEB)

Lin, Yashen [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Afshari, Sina [University of Michigan; Wolfe, John [University of Michigan; Nazir, Md Salman [University of Michigan; Hiskens, Ian A. [University of Michigan; Johnson, Jeremiah X. [University of Michigan; Mathieu, Johanna L. [University of Michigan; Barnes, Arthur K. [Los Alamos National Laboratory; Geller, Drew A. [Los Alamos National Laboratory; Backhaus, Scott N. [Los Alamos National Laboratory

2017-10-03

Heating, ventilation, and air conditioning (HVAC) systems in commercial buildings can provide ancillary services (AS) to the power grid, but by providing AS their energy consumption may increase. This inefficiency is evaluated using round-trip efficiency (RTE), which is defined as the ratio between the decrease and the increase in the HVAC system's energy consumption compared to the baseline consumption as a result of providing AS. This paper evaluates the RTE of a 30,000 m2 commercial building providing AS. We propose two methods to estimate the HVAC system's settling time after an AS event based on temperature and the air flow measurements from the building. Experimental data gathered over a 4-month period are used to calculate the RTE for AS signals of various waveforms, magnitudes, durations, and polarities. The results indicate that the settling time estimation algorithm based on the air flow measurements obtains more accurate results compared to the temperature-based algorithm. Further, we study the impact of the AS signal shape parameters on the RTE and discuss the practical implications of our findings.

Disassembly of JT-60 tokamak device and ancillary facilities for JT-60 tokamak

International Nuclear Information System (INIS)

Okano, Fuminori; Ichige, Hisashi; Miyo, Yasuhiko; Kaminaga, Atsushi; Sasajima, Tadayuki; Nishiyama, Tomokazu; Yagyu, Jun-ichi; Ishige, Youichi; Suzuki, Hiroaki; Komuro, Kenichi; Sakasai, Akira; Ikeda, Yoshitaka

2014-03-01

The disassembly of JT-60 tokamak device and its peripheral equipments, where the total weight was about 5400 tons, started in 2009 and accomplished in October 2012. This disassembly was required process for JT-60SA project, which is the Satellite Tokamak project under Japan-EU international corroboration to modify the JT-60 to the superconducting tokamak. This work was the first experience of disassembling a large radioactive fusion device based on Radiation Hazard Prevention Act in Japan. The cutting was one of the main problems in this disassembly, such as to cut the welded parts together with toroidal field coils, and to cut the vacuum vessel into two. After solving these problems, the disassembly completed without disaster and accident. This report presents the outline of the JT-60 disassembly, especially tokamak device and ancillary facilities for tokamak device. (author)

Flamelet mathematical models for non-premixed laminar combustion

Energy Technology Data Exchange (ETDEWEB)

Carbonell, D.; Perez-Segarra, C.D.; Oliva, A. [Centre Tecnologic de Transferencia de Calor (CTTC), Universitat Politecnica de Catalunya (UPC), Colom 11, E-08222 Terrassa, Barcelona (Spain); Coelho, P.J. [Mechanical Engineering Department, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

2009-02-15

Detailed numerical calculations based on the solution of the full transport equations have been compared with flamelet calculations in order to analyse the flamelet concept for laminar diffusion flames. The goal of this work is to study the interactive (Lagrangian Flamelet Model and Interactive Steady Flamelet Model), and non-interactive (Steady Flamelet Model and Enthalpy Defect Flamelet Model) flamelet models considering both differential diffusion and non-differential diffusion situations, and adiabatic and non-adiabatic conditions. Moreover, a new procedure has been employed to obtain enthalpy defects in the flamelet library, the application of which has been found to be encouraging. The effect of using in-situ, local or stoichiometric scalar dissipation rate conditions, and also the effect of using local or stoichiometric conditions to evaluate the flamelet-like time has been analysed. To improve slow species predictions using the non-interactive models, their transport equations are solved with the reaction terms calculated from the flamelet library, also considering local or stoichiometric conditions in the so-called Extended Flamelet Models. (author)

Building a Practical Natural Laminar Flow Design Capability

Science.gov (United States)

Campbell, Richard L.; Lynde, Michelle N.

2017-01-01

A preliminary natural laminar flow (NLF) design method that has been developed and applied to supersonic and transonic wings with moderate-to-high leading-edge sweeps at flight Reynolds numbers is further extended and evaluated in this paper. The modular design approach uses a knowledge-based design module linked with different flow solvers and boundary layer stability analysis methods to provide a multifidelity capability for NLF analysis and design. An assessment of the effects of different options for stability analysis is included using pressures and geometry from an NLF wing designed for the Common Research Model (CRM). Several extensions to the design module are described, including multiple new approaches to design for controlling attachment line contamination and transition. Finally, a modification to the NLF design algorithm that allows independent control of Tollmien-Schlichting (TS) and cross flow (CF) modes is proposed. A preliminary evaluation of the TS-only option applied to the design of an NLF nacelle for the CRM is performed that includes the use of a low-fidelity stability analysis directly in the design module.

Engineering Task Plan for the Integrity Assessment Examination of Double-Contained Receiver Tanks (DCRT), Catch Tanks and Ancillary facilities

International Nuclear Information System (INIS)

BECKER, D.L.

2000-01-01

This Engineering Task Plan (ETP) presents the integrity assessment examination of three DCRTs, seven catch tanks, and two ancillary facilities located in the 200 East and West Areas of the Hanford Site. The integrity assessment examinations, as described in this ETP, will provide the necessary information to enable the independently qualified registered professional engineer (IQRPE) to assess the condition and integrity of these facilities. The plan is consistent with the Double-Shell Tank Waste Transfer Facilities Integrity Assessment Plan

Experimental investigation of laminar flow of viscous oil through a circular tube having integral axial corrugation roughness and fitted with twisted tapes with oblique teeth

Science.gov (United States)

Pal, Sagnik; Saha, Sujoy Kumar

2015-08-01

The experimental friction factor and Nusselt number data for laminar flow of viscous oil through a circular duct having integral axial corrugation roughness and fitted with twisted tapes with oblique teeth have been presented. Predictive friction factor and Nusselt number correlations have also been presented. The thermohydraulic performance has been evaluated. The major findings of this experimental investigation are that the twisted tapes with oblique teeth in combination with integral axial corrugation roughness perform significantly better than the individual enhancement technique acting alone for laminar flow through a circular duct up to a certain value of fin parameter.

Bryozoan filter feeding in laminar wall layers: flume experiments and computer simulation

DEFF Research Database (Denmark)

Larsen, Poul Scheel; Matlok, Simon; Riisgård, Hans Ulrik

1998-01-01

gradient (1-4 s-1). The laminar wall layer simulated viscous sublayers found in the field for smooth surfaces. Incurrents to lines of 3-10 zooids typically distort paths of particles approaching the colony at heights 1-2 mm above the level of lophophore inlets and theycapture particles from paths 0...... line colony to be about 16 times the frontal area of a simulated lophophore. Fluid particles were captured from paths about 1.3 mm above the sink. At twice the flowrate, the area cleared of particles reduced to about 7 times the frontal area while feeding rate increased by about 19%.KEY WORDS: ambient...

Fully developed laminar flow of two immiscible liquids through horizontal pipes: a variational approach

Energy Technology Data Exchange (ETDEWEB)

Kurban, Adib Paulo Abdalla [PETROBRAS, Rio de Janeiro (Brazil). Centro de Pesquisas; Bannwart, Antonio Carlos [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica

1990-12-31

The fully developed laminar flow of two immiscible liquids with both different viscosities and densities through a horizontal round pipe is studied. The interface between the fluids as well as their flow fields are determined by the use of a variational principle: the so called viscous dissipation principle: The results foreseen by this paper are in agreement with the physical observation (e.g. Southern and Ballman) that the more viscous fluid is total or partially encapsulated by the less viscous one. (author) 8 refs., 4 figs.

Fully developed laminar flow of two immiscible liquids through horizontal pipes: a variational approach

Energy Technology Data Exchange (ETDEWEB)

Kurban, Adib Paulo Abdalla [PETROBRAS, Rio de Janeiro (Brazil). Centro de Pesquisas; Bannwart, Antonio Carlos [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica

1991-12-31

The fully developed laminar flow of two immiscible liquids with both different viscosities and densities through a horizontal round pipe is studied. The interface between the fluids as well as their flow fields are determined by the use of a variational principle: the so called viscous dissipation principle: The results foreseen by this paper are in agreement with the physical observation (e.g. Southern and Ballman) that the more viscous fluid is total or partially encapsulated by the less viscous one. (author) 8 refs., 4 figs.

Numerical analysis of a hypersonic turbulent and laminar flow using a commercial CFD solver

Directory of Open Access Journals (Sweden)

Pajčin Miroslav P.

2017-01-01

Full Text Available Computational fluid dynamics computations for two hypersonic flow cases using the commercial ANSYS FLUENT 16.2 CFD software were done. In this paper, an internal and external hypersonic flow cases were considered and analysis of the hypersonic flow using different turbulence viscosity models available in ANSYS FLUENT 16.2 as well as the laminar viscosity model were done. The obtained results were after compared and commented upon. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 35035

How the Venetian Blind Percept Emergesfrom the Laminar Cortical Dynamics of 3D Vision

OpenAIRE

Stephen eGrossberg

2014-01-01

The 3D LAMINART model of 3D vision and figure-ground perception is used to explain and simulate a key example of the Venetian blind effect and show how it is related to other well-known perceptual phenomena such as Panum's limiting case. The model shows how identified neurons that interact in hierarchically organized laminar circuits of the visual cortex can simulate many properties of 3D vision percepts, notably consciously seen surface percepts, which are predicted to arise when filled-in s...

Stability enhancement of ozone-assisted laminar premixed Bunsen flames in nitrogen co-flow

KAUST Repository

Vu, Tran Manh

2014-04-01

Ozone (O3) is known as one of the strongest oxidizers and therefore is widely used in many applications. Typically in the combustion field, a combination of non-thermal plasma and combustion systems have been studied focusing on the effects of ozone on flame propagation speeds and ignition characteristics. Here, we experimentally investigated the effects of ozone on blowoff of premixed methane/air and propane/air flames over a full range of equivalence ratios at room temperature and atmospheric pressure by using a co-flow burner and a dielectric barrier discharge. The results with ozone showed that a nozzle exit jet velocity at the moment of flame blowoff (blowoff velocity) significantly increased, and flammability limits for both fuel-lean and rich mixtures were also extended. Ozone had stronger effects of percent enhancement in the blowoff velocity for off-stoichiometric mixtures, while minimum enhancements could be observed around stoichiometric conditions for both fuels showing linear positive dependence on a tested range of ozone concentration up to 3810ppm. Through chemical kinetic simulations, the experimentally observed trends of the enhancement in blowoff velocity were identified as a result of the modification of the laminar burning velocity. Two ozone decomposition pathways of O3+N2→O+O2+N2 and O3+H→O2+OH were identified as the most controlling steps. These reactions, coupled with fuel consumption characteristics of each fuel determined the degree of promotion in laminar burning velocities, supporting experimental observations on blowoff velocities with ozone addition. © 2013 The Combustion Institute.

Motion of cells sedimenting on a solid surface in a laminar shear flow.

Science.gov (United States)

Tissot, O; Pierres, A; Foa, C; Delaage, M; Bongrand, P

1992-01-01

Cell adhesion often occurs under dynamic conditions, as in flowing blood. A quantitative understanding of this process requires accurate knowledge of the topographical relationships between the cell membrane and potentially adhesive surfaces. This report describes an experimental study made on both the translational and rotational velocities of leukocytes sedimenting of a flat surface under laminar shear flow. The main conclusions are as follows: (a) Cells move close to the wall with constant velocity for several tens of seconds. (b) The numerical values of translational and rotational velocities are inconsistent with Goldman's model of a neutrally buoyant sphere in a laminar shear flow, unless a drag force corresponding to contact friction between cells and the chamber floor is added. The phenomenological friction coefficient was 7.4 millinewton.s/m. (c) Using a modified Goldman's theory, the width of the gap separating cells (6 microns radius) from the chamber floor was estimated at 1.4 micron. (d) It is shown that a high value of the cell-to-substrate gap may be accounted for by the presence of cell surface protrusions of a few micrometer length, in accordance with electron microscope observations performed on the same cell population. (e) In association with previously reported data (Tissot, O., C. Foa, C. Capo, H. Brailly, M. Delaage, and P. Bongrand. 1991. Biocolloids and Biosurfaces. In press), these results are consistent with the possibility that cell-substrate attachment be initiated by the formation of a single molecular bond, which might be considered as the rate limiting step.

Is the Magnetic Field in the Heliosheath Sector Region and in the Outer Heliosheath Laminar?

Science.gov (United States)

Opher, M.; Drake, J. F.; Swisdak, M. M.; Toth, G.

2010-12-01

All the current global models of the heliosphere are based on the assumption that the magnetic field in the outer heliosheath close to the heliopause is laminar. We argue that in the outer heliosheath the heliospheric magnetic field is not laminar but instead consists of nested magnetic islands. Recently, we proposed (Drake et al. 2009) that the annihilation of the ``sectored'' magnetic field within the heliosheath as it is compressed on its approach to the heliopause produces the anomalous cosmic rays (ACRs) and also energetic electrons. As a product of the annihilation of the sectored magnetic field, densly-packed magnetic islands are produced. These magnetic islands will be convected with the ambient flows as the sector boundary is carried to higher latitudes filling the outer heliosheath. We further argue that the magnetic islands will develop upstream (but still within the heliosheath) where collisionless reconnection is unfavorable -- large perturbations of the sector structure near the heliopause will cause compressions of the current sheet upstream, triggering reconnection. As a result, the magnetic field in the heliosheath sector region will be disordered well upstream of the heliopause. We present a 3D MHD simulation with unprecedent numerical resolution that captures the sector boundary. We show that due to the high pressure of the interstellar magnetic field the disordered sectored region fills a large portion of the northern part of the heliosphere with a smaller extension in the southern hemisphere. We test these ideas with observations of energetic electrons, which because of their high velocity are most sensitive to the structure of the magnetic field. We suggest that within our scenario we can explain two significant anomalies in the observations of energetic electrons in the outer heliosphere: the sudden decrease in the intensity of low energy electrons (0.02-1.5MeV) from the LECP instrument on Voyager 2 in 2008 (Decker 2010); and the dramatic

Dental imaging using laminar optical tomography and micro CT

Science.gov (United States)

Long, Feixiao; Ozturk, Mehmet S.; Intes, Xavier; Kotha, Shiva

2014-02-01

Dental lesions located in the pulp are quite difficult to identify based on anatomical contrast, and, hence, to diagnose using traditional imaging methods such as dental CT. However, such lesions could lead to functional and/or molecular optical contrast. Herein, we report on the preliminary investigation of using Laminar Optical Tomography (LOT) to image the pulp and root canals in teeth. LOT is a non-contact, high resolution, molecular and functional mesoscopic optical imaging modality. To investigate the potential of LOT for dental imaging, we injected an optical dye into ex vivo teeth samples and imaged them using LOT and micro-CT simultaneously. A rigid image registration between the LOT and micro-CT reconstruction was obtained, validating the potential of LOT to image molecular optical contrast deep in the teeth with accuracy, non-invasively. We demonstrate that LOT can retrieve the 3D bio-distribution of molecular probes at depths up to 2mm with a resolution of several hundred microns in teeth.

Postfragmentation density function for bacterial aggregates in laminar flow.

Science.gov (United States)

Byrne, Erin; Dzul, Steve; Solomon, Michael; Younger, John; Bortz, David M

2011-04-01

The postfragmentation probability density of daughter flocs is one of the least well-understood aspects of modeling flocculation. We use three-dimensional positional data of Klebsiella pneumoniae bacterial flocs in suspension and the knowledge of hydrodynamic properties of a laminar flow field to construct a probability density function of floc volumes after a fragmentation event. We provide computational results which predict that the primary fragmentation mechanism for large flocs is erosion. The postfragmentation probability density function has a strong dependence on the size of the original floc and indicates that most fragmentation events result in clumps of one to three bacteria eroding from the original floc. We also provide numerical evidence that exhaustive fragmentation yields a limiting density inconsistent with the log-normal density predicted in the literature, most likely due to the heterogeneous nature of K. pneumoniae flocs. To support our conclusions, artificial flocs were generated and display similar postfragmentation density and exhaustive fragmentation. ©2011 American Physical Society

Laminar burning velocities of near-flammability-limit H{sub 2}-air-steam mixtures

Energy Technology Data Exchange (ETDEWEB)

Loesel Sitar, J V; Chan, C K; Torchia, F; Guerrero, A

1996-12-31

Laminar burning velocities of lean H{sub 2}-air-steam mixtures near the flammability limit were measured by using the pressure-time history of an expanding flame kernel. Although flames in these mixtures are inherently unstable, this difficulty was avoided by using the early pressure rise of the burn. A comparison of results from that method with burning velocities determined from schlieren photographs of the expanding flame kernel gave good agreement. Despite the difficulties, it is believed that the pressure trace method gives results that are useful in modelling reactor accident scenarios. 8 refs., 4 figs.

Material utilizado en la construcción de estructuras laminares

Directory of Open Access Journals (Sweden)

Parsons, John K.

1979-09-01

Full Text Available This article deals with the materials used in the various types of laminated structures: spherical, cylindrical and hyperbolic. The work shows particularly the geometric and structural features of the «ENSPHERE» reticular spheric dome built with laminated timber and discusses its behaviour under various loads, the method followed in its structural analysis and the different tests performed.

Este articulo trata de los materiales empleados en las distintas formas de estructuras laminares: esféricas, cilíndricas e hiperbólicas. De una manera especial se ven las características, tanto geométricas como estructurales, de la bóveda reticulada esférica «ENSPHERE» construida con madera laminada, su comportamiento frente a las diversas cargas, el método seguido para su análisis estructural, así como los diversos ensayos realizados.

Laminar-turbulent transition tripped by step on transonic compressor profile

Science.gov (United States)

Flaszynski, Pawel; Doerffer, Piotr; Szwaba, Ryszard; Piotrowicz, Michal; Kaczynski, Piotr

2018-02-01

The shock wave boundary layer interaction on the suction side of transonic compressor blade is one of the main objectives of TFAST project (Transition Location Effect on Shock Wave Boundary Layer Interaction). The experimental and numerical results for the flow structure investigations are shown for the flow conditions as the existing ones on the suction side of the compressor profile. The two cases are investigated: without and with boundary layer tripping device. In the first case, boundary layer is laminar up to the shock wave, while in the second case the boundary layer is tripped by the step. Numerical results carried out by means of Fine/Turbo Numeca with Explicit Algebraic Reynolds Stress Model including transition modeling are compared with schlieren, Temperature Sensitive Paint and wake measurements. Boundary layer transition location is detected by Temperature Sensitive Paint.

Smart microgrid hierarchical frequency control ancillary service provision based on virtual inertia concept: An integrated demand response and droop controlled distributed generation framework

International Nuclear Information System (INIS)

Rezaei, Navid; Kalantar, Mohsen

2015-01-01

Highlights: • Detailed formulation of the microgrid static and dynamic securities based on droop control and virtual inertia concepts. • Constructing a novel objective function using frequency excursion and rate of change of frequency profiles. • Ensuring the microgrid security subject to the microgrid economic and environmental policies. • Coordinated management of demand response and droop controlled distributed generation resources. • Precise scheduling of day-ahead hierarchical frequency control ancillary services using a scenario based stochastic programming. - Abstract: Low inertia stack, high penetration levels of renewable energy source and great ratio of power deviations in a small power delivery system put microgrid frequency at risk of instability. On the basis of the close coupling between the microgrid frequency and system security requirements, procurement of adequate ancillary services from cost-effective and environmental friendly resources is a great challenge requests an efficient energy management system. Motivated by this need, this paper presents a novel energy management system that is aimed to coordinately manage the demand response and distributed generation resources. The proposed approach is carried out by constructing a hierarchical frequency control structure in which the frequency dependent control functions of the microgrid components are modeled comprehensively. On the basis of the derived modeling, both the static and dynamic frequency securities of an islanded microgrid are provided in primary and secondary control levels. Besides, to cope with the low inertia stack of islanded microgrids, novel virtual inertia concept is devised based on the precise modeling of droop controlled distributed generation resources. The proposed approach is applied to typical test microgrid. Energy and hierarchical reserve resource are scheduled precisely using a scenario-based stochastic programming methodology. Moreover, analyzing the

Strategies for carbon dioxide emissions reductions: Residential natural gas efficiency, economic, and ancillary health impacts in Maryland

International Nuclear Information System (INIS)

Ruth, Matthias; Blohm, Andrew; Mauer, Joanna; Gabriel, Steven A.; Kesana, Vijay G.; Chen Yihsu; Hobbs, Benjamin F.; Irani, Daraius

2010-01-01

As part of its commitments to the Regional Greenhouse Gas Initiative (RGGI), the State of Maryland, USA, auctions emission permits to electric utilities, creating revenue that can be used to benefit consumers and the environment. This paper explores the CO 2 emissions reductions that may be possible by allocating some of that revenue to foster efficiency improvements in the residential sector's use of natural gas. Since these improvements will require changes to the capital stock of houses and end use equipment, efficiency improvements may be accompanied by economic and ancillary health impacts, both of which are quantified in this paper.

Numerical study of laminar nonpremixed methane flames in coflow jets: Autoignited lifted flames with tribrachial edges and MILD combustion at elevated temperatures

KAUST Repository

M. Al-Noman, Saeed; Choi, Sang Kyu; Chung, Suk-Ho

2016-01-01

Autoignition characteristics of laminar nonpremixed methane jet flames in high-temperature coflow air are studied numerically. Several flame configurations are investigated by varying the initial temperature and fuel mole fraction. At a relatively

Chemical kinetic study of a novel lignocellulosic biofuel: Di-n-butyl ether oxidation in a laminar flow reactor and flames

KAUST Repository

Cai, Liming; Sudholt, Alena; Lee, Dongjoon; Egolfopoulos, Fokion N.; Pitsch, Heinz G.; Westbrook, Charles K.; Sarathy, Mani

2014-01-01

The combustion characteristics of promising alternative fuels have been studied extensively in the recent years. Nevertheless, the pyrolysis and oxidation kinetics for many oxygenated fuels are not well characterized compared to those of hydrocarbons. In the present investigation, the first chemical kinetic study of a long-chain linear symmetric ether, di-n-butyl ether (DBE), is presented and a detailed reaction model is developed. DBE has been identified recently as a candidate biofuel produced from lignocellulosic biomass. The model includes both high temperature and low temperature reaction pathways with reaction rates generated using appropriate rate rules. In addition, experimental studies on fundamental combustion characteristics, such as ignition delay times and laminar flame speeds have been performed. A laminar flow reactor was used to determine the ignition delay times of lean and stoichiometric DBE/air mixtures. The laminar flame speeds of DBE/air mixtures were measured in the stagnation flame configuration for a wide rage of equivalence ratios at atmospheric pressure and an unburned reactant temperature of 373. K. All experimental data were modeled using the present kinetic model. The agreement between measured and computed results is satisfactory, and the model was used to elucidate the oxidation pathways of DBE. The dissociation of keto-hydroperoxides, leading to radical chain branching was found to dominate the ignition of DBE in the low temperature regime. The results of the present numerical and experimental study of the oxidation of di-n-butyl ether provide a good basis for further investigation of long chain linear and branched ethers. © 2013 The Combustion Institute.

Chemical kinetic study of a novel lignocellulosic biofuel: Di-n-butyl ether oxidation in a laminar flow reactor and flames

KAUST Repository

Cai, Liming

2014-03-01

The combustion characteristics of promising alternative fuels have been studied extensively in the recent years. Nevertheless, the pyrolysis and oxidation kinetics for many oxygenated fuels are not well characterized compared to those of hydrocarbons. In the present investigation, the first chemical kinetic study of a long-chain linear symmetric ether, di-n-butyl ether (DBE), is presented and a detailed reaction model is developed. DBE has been identified recently as a candidate biofuel produced from lignocellulosic biomass. The model includes both high temperature and low temperature reaction pathways with reaction rates generated using appropriate rate rules. In addition, experimental studies on fundamental combustion characteristics, such as ignition delay times and laminar flame speeds have been performed. A laminar flow reactor was used to determine the ignition delay times of lean and stoichiometric DBE/air mixtures. The laminar flame speeds of DBE/air mixtures were measured in the stagnation flame configuration for a wide rage of equivalence ratios at atmospheric pressure and an unburned reactant temperature of 373. K. All experimental data were modeled using the present kinetic model. The agreement between measured and computed results is satisfactory, and the model was used to elucidate the oxidation pathways of DBE. The dissociation of keto-hydroperoxides, leading to radical chain branching was found to dominate the ignition of DBE in the low temperature regime. The results of the present numerical and experimental study of the oxidation of di-n-butyl ether provide a good basis for further investigation of long chain linear and branched ethers. © 2013 The Combustion Institute.

Critical Joints in Large Composite Primary Aircraft Structures. Volume 3: Ancillary Test Results

Science.gov (United States)

Bunin, Bruce L.; Sagui, R. L.

1985-01-01

A program was conducted to develop the technology for critical structural joints for composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. The results of a comprehensive ancillary test program are summarized, consisting of single-bolt composite joint specimens tested in a variety of configurations. These tests were conducted to characterize the strength and load deflection properties that are required for multirow joint analysis. The composite material was Toray 300 fiber and Ciba-Geigy 914 resin, in the form of 0.005 and 0.01 inch thick unidirectional tape. Tests were conducted in single and double shear for loaded and unloaded hole configurations under both tensile and compressive loading. Two different layup patterns were examined. All tests were conducted at room temperature. In addition, the results of NASA Standard Toughness Test (NASA RP 1092) are reported, which were conducted for several material systems.

Ancillary testing, diagnostic/classification criteria and severity grading in Behçet disease.

Science.gov (United States)

Okada, Annabelle A; Stanford, Miles; Tabbara, Khalid

2012-12-01

Since there is no pathognomonic clinical sign or laboratory test to distinguish Behçet disease from other uveitic entities, the diagnosis must be made based on characteristic ocular and systemic findings in the absence of evidence of other disease that can explain the findings. Ancillary tests, including ocular and brain imaging studies, are used to assess the severity of intraocular inflammation and systemic manifestations of Behçet disease, to identify latent infections and other medical conditions that might worsen with systemic treatment, and to monitor for adverse effects of drugs used. There are two diagnostic or classification criteria in general use by the uveitis community, one from Japan and one from an international group; both rely on a minimum number and/or combination of clinical findings to identify Behçet disease. Finally, several grading schemes have been proposed to assess severity of ocular disease and response to treatment.

Numerical investigation of Al2O3/water nanofluid laminar convective heat transfer through triangular ducts

Directory of Open Access Journals (Sweden)

Zeinali Heris Saeed

2011-01-01

Full Text Available Abstract In this article, laminar flow-forced convective heat transfer of Al2O3/water nanofluid in a triangular duct under constant wall temperature condition is investigated numerically. In this investigation, the effects of parameters, such as nanoparticles diameter, concentration, and Reynolds number on the enhancement of nanofluids heat transfer is studied. Besides, the comparison between nanofluid and pure fluid heat transfer is achieved in this article. Sometimes, because of pressure drop limitations, the need for non-circular ducts arises in many heat transfer applications. The low heat transfer rate of non-circular ducts is one the limitations of these systems, and utilization of nanofluid instead of pure fluid because of its potential to increase heat transfer of system can compensate this problem. In this article, for considering the presence of nanoparticl: es, the dispersion model is used. Numerical results represent an enhancement of heat transfer of fluid associated with changing to the suspension of nanometer-sized particles in the triangular duct. The results of the present model indicate that the nanofluid Nusselt number increases with increasing concentration of nanoparticles and decreasing diameter. Also, the enhancement of the fluid heat transfer becomes better at high Re in laminar flow with the addition of nanoparticles.

Play Practices and Play Moods

DEFF Research Database (Denmark)

Karoff, Helle Skovbjerg

2013-01-01

The aim of this article is to develop a view of play as a relation between play practices and play moods based on an empirical study of children's everyday life and by using Bateson's term of ‘framing’ [(1955/2001). In Steps to an ecology of mind (pp. 75–80). Chicago: University of Chicago Press......], Schmidt's notion of ‘commonness’ [(2005). Om respekten. København: Danmarks Pædagogiske Universitets Forlag; (2011). On respect. Copenhagen: Danish School of Education University Press] and Heidegger's term ‘mood’ [(1938/1996). Time and being. Cornwall: Wiley-Blackwell.]. Play mood is a state of being...... in which we are open and ready, both to others and their production of meaning and to new opportunities for producing meaning. This play mood is created when we engage with the world during play practices. The article points out four types of play moods – devotion, intensity, tension and euphorica – which...

Designing Out the Play: Accessibility and Playfulness in Inclusive Play.

Science.gov (United States)

Holt, Raymond; Beckett, Angharad

2017-01-01

Play is an important part of child development, yet disabled children are often excluded from the opportunity to play, either due to lack of accessible toys and games, or social pressures. This paper presents a case study reflecting on the development of Button Bash: a switch accessible game intended to encourage inclusive play between disabled and non-disabled children. In particular, the paper focuses on how changes intended to make the game more accessible tended to make it less playful, and reflects on the relationship between playfulness and accessibility.

Stochastic scheduling of aggregators of plug-in electric vehicles for participation in energy and ancillary service markets

International Nuclear Information System (INIS)

Alipour, Manijeh; Mohammadi-Ivatloo, Behnam; Moradi-Dalvand, Mohammad; Zare, Kazem

2017-01-01

Plug-in electric vehicles are expected to play a major role in the transportation system as the environmental problems and energy crisis are being more and more urgent recently. Implementing a large number of vehicles with proper control could bring an opportunity of large storage and flexibility for power systems. The plug-in electric vehicle aggregator is responsible for providing power and controlling the charging pattern of the plug-in electric vehicles under its contracted area. This paper deals with the problem of optimal scheduling problem of plug-in electric vehicle aggregators in electricity market considering the uncertainties of market prices, availability of vehicles and status of being called by the ISO in the reserve market. The impact of the market price and reserve market uncertainties on the electric vehicle scheduling problem is characterized through a stochastic programming framework. The objective of the aggregator is to maximize its profit by charging the plug-in electric vehicles on the low price time intervals as well as participating in ancillary service markets. The operational constraints of plug-in electric vehicles and constraints of vehicle to grid are modeled in the proposed framework. An illustrative example is provided to confirm the performance of the proposed model. - Highlights: • Optimal scheduling of vehicle aggregators in electricity market has been addressed. • The operational constraints of plug-in vehicle to grid are considered. • The uncertainties of calling status in reserve market and market prices are modeled. • Vehicles' driving patterns and availability uncertainty are modeled. • The effect of risk measure weight in the vehicle to grid model has been studied.

Assessment of CFD Capability for Hypersonic Shock Wave Laminar Boundary Layer Interactions

Directory of Open Access Journals (Sweden)

Mehrnaz Rouhi Youssefi

2017-04-01

Full Text Available The goal of this study is to assess CFD capability for the prediction of shock wave laminar boundary layer interactions at hypersonic velocities. More specifically, the flow field over a double-cone configuration is simulated using both perfect gas and non-equilibrium Navier–Stokes models. Computations are compared with recent experimental data obtained from measurements conducted in the LENS XX (Large Energy National Shock Expansion Tunnel Version 2 at the Calspan University of Buffalo Research Center (CUBRC. Four separate cases of freestream conditions are simulated to examine the models for a range of stagnation enthalpies from 5.44 MJ/kg to 21.77 MJ/kg and Mach numbers from 10.9 to 12.82.