Selecting suitable enclosures for digitally printed materials

International Nuclear Information System (INIS)

Burge, D; Rima, L

2010-01-01

It cannot be assumed that storage enclosures considered safe for traditionally printed images and documents are suitable for modern, digitally printed materials. In this project, a large variety of digital print types were tested using a modified version of the ISO 18916 Imaging materials-Processed imaging materials-Photographic activity test for enclosure materials standard to assess the risk to digital prints by paper enclosures known to be inert or reactive with traditional photographic prints. The types of enclosures tested included buffered and non-buffered cotton papers, and groundwood paper. In addition, qualitative filter paper that had been wetted and dried with either an acidic or basic solution was also tested to determine the effects of enclosure pH on digitally printed materials. It was determined that, in general, digital prints tended to be less reactive with various enclosure types than traditional prints. Digital prints were most sensitive to paper that contained groundwood. The enclosure reactivity test results were then integrated with previous published work on the tendencies of various enclosure types to abrade, ferrotype, or block to digital prints in order to create a comprehensive set of recommendations for digital print storage enclosures.

Some comments on the hydrogen atom in a spherical enclosure

International Nuclear Information System (INIS)

Aguilera-Navarro, V.C.; Koo, E.L.; Zimerman, A.H.

1980-01-01

Some properties of the ground state energy solutions for the hydrogen atom in a spherical enclosure are discussed. The application of the many-point Pade approximants to this kind of systems inside a box is consider also. (Author) [pt

30 CFR 56.12068 - Locking transformer enclosures.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Locking transformer enclosures. 56.12068 Section 56.12068 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... § 56.12068 Locking transformer enclosures. Transformer enclosures shall be kept locked against...

30 CFR 57.12068 - Locking transformer enclosures.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Locking transformer enclosures. 57.12068 Section 57.12068 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Electricity Surface Only § 57.12068 Locking transformer enclosures. Transformer enclosures shall be kept...

Acoustic absorption of natural gas compression facility enclosures

Energy Technology Data Exchange (ETDEWEB)

Lassen, P.; Wong, G. [Noise Management Ltd., Calgary, AB (Canada)

2009-07-01

Noise sources at gas compressor facilities include the enclosure/building housing a gas engine and compressor, the ventilation openings, doors and windows for the enclosure, the engine air intake and exhaust, and a cooler. Accurate predictions of the noise levels inside the enclosure, the breakout noise from open windows and doors and ventilation, as well as the transmission through the walls, is necessary in order to determine cost effective noise mitigation for the facility. In order to accurately predict the sound breakout from these facilities it is necessary to know the acoustic absorption of the interior of these equipment enclosures. Although the acoustic absorption data of the wall systems may be available, the absorption attributable to the non-enclosure surfaces, the equipment and fittings, is not usually known and is difficult to predict. Since piping, instrumentation and mechanical equipment often take on a typical arrangement, shape, volumetric density and material composition, it is useful to know the typical acoustic absorption attributable to these items. In this study, reverberation time (RT) measurements were taken at 2 decommissioned gas compressor facilities in order to determine the absorption characteristics of the enclosure. The RT was measured according to ASTM C423-02a. The overall absorption coefficient of a compressor enclosure with a solid liner was found to be similar to that of steel decking. Fittings within the enclosure did not increase the high frequency absorption of the enclosure. It was concluded that room modes, structural vibrations, and fittings may serve to increase the effective absorption at frequencies below 630 Hz. Because of the small dimensions of the enclosure, low-frequency response of the room affected the reliability of the data below 160Hz. Structural vibration of the enclosure was investigated, and may considerably influence the noise breakout from the enclosure apart from the interior acoustical considerations. 4

Acoustic absorption of natural gas compression facility enclosures

International Nuclear Information System (INIS)

Lassen, P.; Wong, G.

2009-01-01

Noise sources at gas compressor facilities include the enclosure/building housing a gas engine and compressor, the ventilation openings, doors and windows for the enclosure, the engine air intake and exhaust, and a cooler. Accurate predictions of the noise levels inside the enclosure, the breakout noise from open windows and doors and ventilation, as well as the transmission through the walls, is necessary in order to determine cost effective noise mitigation for the facility. In order to accurately predict the sound breakout from these facilities it is necessary to know the acoustic absorption of the interior of these equipment enclosures. Although the acoustic absorption data of the wall systems may be available, the absorption attributable to the non-enclosure surfaces, the equipment and fittings, is not usually known and is difficult to predict. Since piping, instrumentation and mechanical equipment often take on a typical arrangement, shape, volumetric density and material composition, it is useful to know the typical acoustic absorption attributable to these items. In this study, reverberation time (RT) measurements were taken at 2 decommissioned gas compressor facilities in order to determine the absorption characteristics of the enclosure. The RT was measured according to ASTM C423-02a. The overall absorption coefficient of a compressor enclosure with a solid liner was found to be similar to that of steel decking. Fittings within the enclosure did not increase the high frequency absorption of the enclosure. It was concluded that room modes, structural vibrations, and fittings may serve to increase the effective absorption at frequencies below 630 Hz. Because of the small dimensions of the enclosure, low-frequency response of the room affected the reliability of the data below 160Hz. Structural vibration of the enclosure was investigated, and may considerably influence the noise breakout from the enclosure apart from the interior acoustical considerations. 4

AUTOMATIC REGISTRATION OF TERRESTRIAL LASER SCANNER POINT CLOUDS USING NATURAL PLANAR SURFACES

Directory of Open Access Journals (Sweden)

P. W. Theiler

2012-07-01

Full Text Available Terrestrial laser scanners have become a standard piece of surveying equipment, used in diverse fields like geomatics, manufacturing and medicine. However, the processing of today's large point clouds is time-consuming, cumbersome and not automated enough. A basic step of post-processing is the registration of scans from different viewpoints. At present this is still done using artificial targets or tie points, mostly by manual clicking. The aim of this registration step is a coarse alignment, which can then be improved with the existing algorithm for fine registration. The focus of this paper is to provide such a coarse registration in a fully automatic fashion, and without placing any target objects in the scene. The basic idea is to use virtual tie points generated by intersecting planar surfaces in the scene. Such planes are detected in the data with RANSAC and optimally fitted using least squares estimation. Due to the huge amount of recorded points, planes can be determined very accurately, resulting in well-defined tie points. Given two sets of potential tie points recovered in two different scans, registration is performed by searching for the assignment which preserves the geometric configuration of the largest possible subset of all tie points. Since exhaustive search over all possible assignments is intractable even for moderate numbers of points, the search is guided by matching individual pairs of tie points with the help of a novel descriptor based on the properties of a point's parent planes. Experiments show that the proposed method is able to successfully coarse register TLS point clouds without the need for artificial targets.

Automatic Registration of Terrestrial Laser Scanner Point Clouds Using Natural Planar Surfaces

Science.gov (United States)

Theiler, P. W.; Schindler, K.

2012-07-01

Terrestrial laser scanners have become a standard piece of surveying equipment, used in diverse fields like geomatics, manufacturing and medicine. However, the processing of today's large point clouds is time-consuming, cumbersome and not automated enough. A basic step of post-processing is the registration of scans from different viewpoints. At present this is still done using artificial targets or tie points, mostly by manual clicking. The aim of this registration step is a coarse alignment, which can then be improved with the existing algorithm for fine registration. The focus of this paper is to provide such a coarse registration in a fully automatic fashion, and without placing any target objects in the scene. The basic idea is to use virtual tie points generated by intersecting planar surfaces in the scene. Such planes are detected in the data with RANSAC and optimally fitted using least squares estimation. Due to the huge amount of recorded points, planes can be determined very accurately, resulting in well-defined tie points. Given two sets of potential tie points recovered in two different scans, registration is performed by searching for the assignment which preserves the geometric configuration of the largest possible subset of all tie points. Since exhaustive search over all possible assignments is intractable even for moderate numbers of points, the search is guided by matching individual pairs of tie points with the help of a novel descriptor based on the properties of a point's parent planes. Experiments show that the proposed method is able to successfully coarse register TLS point clouds without the need for artificial targets.

Flows and Stratification of an Enclosure Containing Both Localised and Vertically Distributed Sources of Buoyancy

Science.gov (United States)

Partridge, Jamie; Linden, Paul

2013-11-01

We examine the flows and stratification established in a naturally ventilated enclosure containing both a localised and vertically distributed source of buoyancy. The enclosure is ventilated through upper and lower openings which connect the space to an external ambient. Small scale laboratory experiments were carried out with water as the working medium and buoyancy being driven directly by temperature differences. A point source plume gave localised heating while the distributed source was driven by a controllable heater mat located in the side wall of the enclosure. The transient temperatures, as well as steady state temperature profiles, were recorded and are reported here. The temperature profiles inside the enclosure were found to be dependent on the effective opening area A*, a combination of the upper and lower openings, and the ratio of buoyancy fluxes from the distributed and localised source Ψ =Bw/Bp . Industrial CASE award with ARUP.

Nuclear power plant with a safety enclosure

International Nuclear Information System (INIS)

Keller, W.; Krueger, J.; Ropers, J.; Schabert, H.P.

1976-01-01

A nuclear power plant has a safety enclosure for a nuclear reactor. A fuel element storage basin is also located in this safety enclosure and a fuel element lock extends through the enclosure, with a cross-sectional size proportioned for the endwise passage of fuel elements, the lock including internal and external valves so that a fuel element may be locked endwise safely through the lock. The lock, including its valves, being of small size, does not materially affect the pressure resistance of the safety enclosure, and it is more easily operated than a lock large enough to pass people and fuel element transport vessels

50 CFR 14.142 - Primary enclosures.

Science.gov (United States)

2010-10-01

... 50 Wildlife and Fisheries 1 2010-10-01 2010-10-01 false Primary enclosures. 14.142 Section 14.142 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR TAKING... outside the enclosure. Specifications for Sloths, Bats, and Flying Lemurs (Cynocephalidae) ...

The 3.5-Meter Telescope Enclosure

Science.gov (United States)

1994-04-01

and acoustic vibrations, and the enclosure cannot be stopped quickly in an emergency. Also, the work of Zago indicates that open-air operation of the...enclosure. This capability is useful during operational testing and maintenance of the telescope. ’ Zago , L., "Design and Performance of Large

Humidity evolution (breathing effect) in enclosures with electronics

DEFF Research Database (Denmark)

Hygum, Morten Arnfeldt; Popok, Vladimir

2015-01-01

Packaging and enclosures used for protecting power electronics operating outdoors are designed to withstand the local climatic and environmental changes. Hermetic enclosures are expensive and therefore other solutions for protecting the electronics from a harsh environment are required. One...... of the dangerous parameters is high humidity of air. Moisture can inevitable reach the electronics either due to diffusion through the wall of an enclosure or small holes, which are designed for electrical or other connections. A driving force for humid air movement is the temperature difference between...... the operating electronics and the surrounding environment. This temperature, thus, gives rise to a natural convection, which we also refer to as breathing. Robust and intelligent enclosure designs must account for this breathing as it can significantly change the humidity distribution in the enclosure...

Modified planar functions and their components

DEFF Research Database (Denmark)

Anbar Meidl, Nurdagül; Meidl, Wilfried Meidl

2017-01-01

functions in odd characteristic as a vectorial bent function. We finally point out that though these components behave somewhat different than the multivariate bent4 functions, they are bent or semibent functions shifted by a certain quadratic term, a property which they share with their multivariate......Zhou ([20]) introduced modified planar functions in order to describe (2n; 2n; 2n; 1) relative difference sets R as a graph of a function on the finite field F2n, and pointed out that projections of R are difference sets that can be described by negabent or bent4 functions, which are Boolean...... functions given in multivariate form. One of the objectives of this paper is to contribute to the understanding of these component functions of modified planar functions. Moreover, we obtain a description of modified planar functions by their components which is similar to that of the classical planar...

Limiting enclosures - Filtering fittings for air or gas

International Nuclear Information System (INIS)

1981-05-01

The aim of this experimental standard is the determination of the general characteristics of air or gas filtration equipment for limiting enclosures in application of the standard M 62-202. Application are made on enclosures or enclosure lines used for works on radioactive materials, toxic or dangerous chemicals, materials sensitive to atmospheric components or requiring a steril atmosphere [fr

Dynamic Planar Convex Hull

DEFF Research Database (Denmark)

Brodal, Gerth Stølfting; Jacob, Rico

2002-01-01

In this paper we determine the computational complexity of the dynamic convex hull problem in the planar case. We present a data structure that maintains a finite set of n points in the plane under insertion and deletion of points in amortized O(log n) time per operation. The space usage of the d......In this paper we determine the computational complexity of the dynamic convex hull problem in the planar case. We present a data structure that maintains a finite set of n points in the plane under insertion and deletion of points in amortized O(log n) time per operation. The space usage...... of the data structure is O(n). The data structure supports extreme point queries in a given direction, tangent queries through a given point, and queries for the neighboring points on the convex hull in O(log n) time. The extreme point queries can be used to decide whether or not a given line intersects...... the convex hull, and the tangent queries to determine whether a given point is inside the convex hull. We give a lower bound on the amortized asymptotic time complexity that matches the performance of this data structure....

Preconceptual design for the electrostatic enclosure

International Nuclear Information System (INIS)

Meyer, L.C.

1992-09-01

This report presents a preconceptual design (design criteria and assumptions) for electrostatic enclosures to be used during buried transuranic waste recovery operations. These electrostatic enclosures (along with the application of dust control products) will provide an in-depth contamination control strategy. As part of this preconceptual design, options for electrostatic curtain design are given including both hardwall and fabric enclosures. Ventilation systems, doors, air locks, electrostatic curtains, and supporting systems also are discussed. In addition to the conceptual design, engineering scale tests are proposed to be run at the Test Reactor Area. The planned engineering scale tests will give final material specifications for full-scale retrieval demonstrations

Fire Research Enclosure

Data.gov (United States)

Federal Laboratory Consortium — FUNCTION: Simulates submarine fires, enclosed aircraft fires, and fires in enclosures at shore facilities .DESCRIPTION: FIRE I is a pressurizable, 324 cu m(11,400 cu...

MROI Array telescopes: the relocatable enclosure domes

Science.gov (United States)

Marchiori, G.; Busatta, A.; Payne, I.

2016-07-01

The MROI - Magdalena Ridge Interferometer is a project which comprises an array of up to 10 1.4m diameter mirror telescopes arranged in a "Y" configuration. Each of these telescopes will be housed inside a Unit Telescope Enclosure (UTE) which are relocatable onto any of 28 stations. EIE GROUP Srl, Venice - Italy, was awarded the contract for the design, the construction and the erection on site of the MROI by the New Mexico Institute of Mining and Technology. The close-pack array of the MROI - including all 10 telescopes, several of which are at a relative distance of less than 8m center to center from each other - necessitated an original design for the Unit Telescope Enclosure (UTE). This innovative design enclosure incorporates a unique dome/observing aperture system to be able to operate in the harsh environmental conditions encountered at an altitude of 10,460ft (3,188m). The main characteristics of this Relocatable Enclosure Dome are: a Light insulated Steel Structure with a dome made of composites materials (e.g. glass/carbon fibers, sandwich panels etc.), an aperture motorized system for observation, a series of louvers for ventilation, a series of electrical and plants installations and relevant auxiliary equipment. The first Enclosure Dome is now under construction and the completion of the mounting on site id envisaged by the end of 2016. The relocation system utilizes a modified reachstacker (a transporter used to handle freight containers) capable of maneuvering between and around the enclosures, capable of lifting the combined weight of the enclosure with the telescope (30tons), with minimal impacts due to vibrations.

Modeling and Eigenfrequency Analysis of Sound-Structure Interaction in a Rectangular Enclosure with Finite Element Method

Directory of Open Access Journals (Sweden)

Samira Mohamady

2009-01-01

Full Text Available Vibration of structures due to external sound is one of the main causes of interior noise in cavities like automobile, aircraft, and rotorcraft, which disturb the comfort of passengers. Accurate modelling of such phenomena is required in eigenfrequency analysis and in designing an active noise control system to reduce the interior noise. In this paper, the effect of periodic noise travelling into a rectangular enclosure is investigated with finite element method (FEM using COMSOL Multiphysics software. The periodic acoustic wave is generated by a point source outside the enclosure and propagated through the enclosure wall and excites an aluminium flexible panel clamped onto the enclosure. The behaviour of the transmission of sound into the cavity is investigated by computing the modal characteristics and the natural frequencies of the cavity. The simulation results are compared with previous analytical and experimental works for validation and an acceptable match between them were obtained.

40 CFR 86.117-96 - Evaporative emission enclosure calibrations.

Science.gov (United States)

2010-07-01

... periodic determination of enclosure background emissions. Prior to its introduction into service, annually... procedure: (1) Carefully measure the internal length, width and height of the enclosure, accounting for... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Evaporative emission enclosure...

Shielded enclosure for handling radioactive material

International Nuclear Information System (INIS)

Laurent, H.; Courouble, J.M.

1959-01-01

Two enclosures linked by an air-lock are described: they are designed for the safe handling of 5 curies 0.3 to 0.5 MeV γ emitters, and each is composed of a semi-tight case, ventilated, clad in 80 mm steel plate, and suited for a wide variety of physics and chemistry operations. The equipment required for any given operation can be installed in the shortest possible time, access to the enclosure being via a removable front. Visual control is assured through a lead-glass screen. Each enclosure is fitted with a master-slave manipulator, Argon model 7, and plugs and air-locks are provided for the introduction of liquids and solids. (author) [fr

DKIST enclosure modeling and verification during factory assembly and testing

Science.gov (United States)

Larrakoetxea, Ibon; McBride, William; Marshall, Heather K.; Murga, Gaizka

2014-08-01

The Daniel K. Inouye Solar Telescope (DKIST, formerly the Advanced Technology Solar Telescope, ATST) is unique as, apart from protecting the telescope and its instrumentation from the weather, it holds the entrance aperture stop and is required to position it with millimeter-level accuracy. The compliance of the Enclosure design with the requirements, as of Final Design Review in January 2012, was supported by mathematical models and other analyses which included structural and mechanical analyses (FEA), control models, ventilation analysis (CFD), thermal models, reliability analysis, etc. During the Enclosure Factory Assembly and Testing the compliance with the requirements has been verified using the real hardware and the models created during the design phase have been revisited. The tests performed during shutter mechanism subsystem (crawler test stand) functional and endurance testing (completed summer 2013) and two comprehensive system-level factory acceptance testing campaigns (FAT#1 in December 2013 and FAT#2 in March 2014) included functional and performance tests on all mechanisms, off-normal mode tests, mechanism wobble tests, creation of the Enclosure pointing map, control system tests, and vibration tests. The comparison of the assumptions used during the design phase with the properties measured during the test campaign provides an interesting reference for future projects.

Track plate enclosures: Box designs affecting attractiveness to riparian mammals

Science.gov (United States)

Loukmas, J.J.; Mayack, D.T.; Richmond, M.E.

2003-01-01

We examined the efficacy of four track plate enclosure designs for monitoring the abundance of small and medium-sized mammals along 10 streams in New York State. Box size and clarity of view through the box were evaluated as factors affecting visitation. We checked track plate stations weekly from September 1999 to March 2000. Eleven mammalian species or species groups visited the track plate stations. Raccoons (Procyon lotor) (P = 0.020) and feral cats (Felis catus) (P = 0.008) visited large enclosures significantly more than small enclosures. Feral cats visited clear-view enclosures significantly more than obstructed-view enclosures (P = 0.025). Enclosure size and view did not significantly affect visitation by other species; however, a large box with a clear view was the most effective design.

Procedure for estimating permanent total enclosure costs

Energy Technology Data Exchange (ETDEWEB)

Lukey, M.E.; Prasad, C.; Toothman, D.A.; Kaplan, N.

1999-07-01

Industries that use add-on control devices must adequately capture emissions before delivering them to the control device. One way to capture emissions is to use permanent total enclosures (PTEs). By definition, an enclosure which meets the US Environmental Protection Agency's five-point criteria is a PTE and has a capture efficiency of 100%. Since costs play an important role in regulatory development, in selection of control equipment, and in control technology evaluations for permitting purposes, EPA has developed a Control Cost Manual for estimating costs of various items of control equipment. EPA's Manual does not contain any methodology for estimating PTE costs. In order to assist environmental regulators and potential users of PTEs, a methodology for estimating PTE costs was developed under contract with EPA, by Pacific Environmental Services, Inc. (PES) and is the subject of this paper. The methodology for estimating PTE costs follows the approach used for other control devices in the Manual. It includes procedures for sizing various components of a PTE and for estimating capital as well as annual costs. It contains verification procedures for demonstrating compliance with EPA's five-point criteria. In addition, procedures are included to determine compliance with Occupational Safety and Health Administration (OSHA) standards. Meeting these standards is an important factor in properly designing PTEs. The methodology is encoded in Microsoft Exel spreadsheets to facilitate cost estimation and PTE verification. Examples are given throughout the methodology development and in the spreadsheets to illustrate the PTE design, verification, and cost estimation procedures.

Procedure for estimating permanent total enclosure costs

Energy Technology Data Exchange (ETDEWEB)

Lukey, M E; Prasad, C; Toothman, D A; Kaplan, N

1999-07-01

Industries that use add-on control devices must adequately capture emissions before delivering them to the control device. One way to capture emissions is to use permanent total enclosures (PTEs). By definition, an enclosure which meets the US Environmental Protection Agency's five-point criteria is a PTE and has a capture efficiency of 100%. Since costs play an important role in regulatory development, in selection of control equipment, and in control technology evaluations for permitting purposes, EPA has developed a Control Cost Manual for estimating costs of various items of control equipment. EPA's Manual does not contain any methodology for estimating PTE costs. In order to assist environmental regulators and potential users of PTEs, a methodology for estimating PTE costs was developed under contract with EPA, by Pacific Environmental Services, Inc. (PES) and is the subject of this paper. The methodology for estimating PTE costs follows the approach used for other control devices in the Manual. It includes procedures for sizing various components of a PTE and for estimating capital as well as annual costs. It contains verification procedures for demonstrating compliance with EPA's five-point criteria. In addition, procedures are included to determine compliance with Occupational Safety and Health Administration (OSHA) standards. Meeting these standards is an important factor in properly designing PTEs. The methodology is encoded in Microsoft Exel spreadsheets to facilitate cost estimation and PTE verification. Examples are given throughout the methodology development and in the spreadsheets to illustrate the PTE design, verification, and cost estimation procedures.

Enclosure enhancement of flight performance

KAUST Repository

Ghommem, Mehdi; Garcia, Daniel; Calo, Victor M.

2014-01-01

We use a potential flow solver to investigate the aerodynamic aspects of flapping flights in enclosed spaces. The enclosure effects are simulated by the method of images. Our study complements previous aerodynamic analyses which considered only the near-ground flight. The present results show that flying in the proximity of an enclosure affects the aerodynamic performance of flapping wings in terms of lift and thrust generation and power consumption. It leads to higher flight efficiency and more than 5% increase of the generation of lift and thrust.

Enclosure enhancement of flight performance

KAUST Repository

Ghommem, Mehdi

2014-08-19

We use a potential flow solver to investigate the aerodynamic aspects of flapping flights in enclosed spaces. The enclosure effects are simulated by the method of images. Our study complements previous aerodynamic analyses which considered only the near-ground flight. The present results show that flying in the proximity of an enclosure affects the aerodynamic performance of flapping wings in terms of lift and thrust generation and power consumption. It leads to higher flight efficiency and more than 5% increase of the generation of lift and thrust.

Enclosure enhancement of flight performance

Directory of Open Access Journals (Sweden)

Mehdi Ghommem

2014-01-01

Full Text Available We use a potential flow solver to investigate the aerodynamic aspects of flapping flights in enclosed spaces. The enclosure effects are simulated by the method of images. Our study complements previous aerodynamic analyses which considered only the near-ground flight. The present results show that flying in the proximity of an enclosure affects the aerodynamic performance of flapping wings in terms of lift and thrust generation and power consumption. It leads to higher flight efficiency and more than 5% increase of the generation of lift and thrust.

30 CFR 75.819 - Motor-starter enclosures; barriers and interlocks.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Motor-starter enclosures; barriers and...-Voltage Distribution High-Voltage Longwalls § 75.819 Motor-starter enclosures; barriers and interlocks. Compartment separation and cover interlock switches for motor-starter enclosures must be maintained in...

Interaction Between Flow Elements in Large Enclosures

DEFF Research Database (Denmark)

Heiselberg, Per

and if this influences the overall air flow pattern in the enclosure. The main emphasis has been put on the pathways of chilled free air jets and whether the convective flows from both distributed and concentrated heat sources affect the pathway of the jet and the air flow pattern in the enclosure as a function......In this paper experiments in a scale model are used as a first attempt to investigate how different flow elements such as supply air jets, thermal plumes and free convection flows interact with each other in a large enclosure, if the path of each individual flow element changes...... of the location of the heat source and as a function of the heat supplied by the source....

Tridentine enclosure gaps. Controversies and Limitations of Policies for Nuns…Still with Felipe IV

Directory of Open Access Journals (Sweden)

Ángela Atienza López

2014-12-01

Full Text Available The Council of Trent ordered that the strict enclosure for nuns should be carried out. The aim of this paper is to contribute to the analysis of those provisions, pointing out that such monastic discipline had a highly questionable success. The process was full of problems. Even one century after Trent, King Felipe IV still cried out to the situation and deployed a political offensive to reach its imposition. The study of these sources allows us to show the Trent enclosure gaps: how the lack of consent was spread even among the elites of secular and ecclesiastical power, and it hampered its implementation; also how the reality of monastic vows and convent life imposed limits hindering its success; how nuns refused and got support from different sectors; and, on the end, how daily practice of enclosure ran through other channels, where stringency rules could be reconsidered in time and place and could meet their arrangements, more or less lenient, and could be negotiated and renegotiated in everyday life, so that strains could be overcome.

Enclosure for handling high activity materials

International Nuclear Information System (INIS)

Jimeno de Osso, F.

1977-01-01

One of the most important problems that are met at the laboratories producing and handling radioisotopes is that of designing, building and operating enclosures suitable for the safe handling of active substances. With this purpose in mind, an enclosure has been designed and built for handling moderately high activities under a shielding made of 150 mm thick lead. In this report a description is given of those aspects that may be of interest to people working in this field. (Author)

Enclosure for handling high activity materials

Energy Technology Data Exchange (ETDEWEB)

Jimeno de Osso, F

1977-07-01

One of the most important problems that are met at the laboratories producing and handling radioisotopes is that of designing, building and operating enclosures suitable for the safe handling of active substances. With this purpose in mind, an enclosure has been designed and built for handling moderately high activities under a shielding made of 150 mm thick lead. In this report a description is given of those aspects that may be of interest to people working in this field. (Author)

Natural convection in asymmetric triangular enclosures heated from below

Science.gov (United States)

Kamiyo, O. M.; Angeli, D.; Barozzi, G. S.; Collins, M. W.

2014-11-01

Triangular enclosures are typical configurations of attic spaces found in residential as well as industrial pitched-roof buildings. Natural convection in triangular rooftops has received considerable attention over the years, mainly on right-angled and isosceles enclosures. In this paper, a finite volume CFD package is employed to study the laminar air flow and temperature distribution in asymmetric rooftop-shaped triangular enclosures when heated isothermally from the base wall, for aspect ratios (AR) 0.2 <= AR <= 1.0, and Rayleigh number (Ra) values 8 × 105 <= Ra <= 5 × 107. The effects of Rayleigh number and pitch angle on the flow structure and temperature distributions within the enclosure are analysed. Results indicate that, at low pitch angle, the heat transfer between the cold inclined and the hot base walls is very high, resulting in a multi-cellular flow structure. As the pitch angle increases, however, the number of cells reduces, and the total heat transfer rate progressively reduces, even if the Rayleigh number, being based on the enclosure height, rapidly increases. Physical reasons for the above effect are inspected.

46 CFR 169.677 - Equipment protection and enclosure.

Science.gov (United States)

2010-10-01

... Vessels of Less Than 100 Gross Tons § 169.677 Equipment protection and enclosure. (a) Except as provided... 46 Shipping 7 2010-10-01 2010-10-01 false Equipment protection and enclosure. 169.677 Section 169.677 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL...

Digital enclosure and the communication commons revival

OpenAIRE

Anderson, Stephen Edward

2008-01-01

This thesis considers the political and economic forces shaping the Internet as a medium of increasing importance in everyday life. The digital communications infrastructure is currently facing commercial enclosure on three layers: physical (regulation and ownership of the wires), content (copyright policies, media technology, ownership), and space (ownership and orientation of online tools, spaces, and services). This thesis explores and analyzes the power dynamics driving enclosure on each ...

Effect of interior geometry on local climate inside an electronic device enclosure

DEFF Research Database (Denmark)

Joshy, Salil; Jellesen, Morten Stendahl; Ambat, Rajan

2017-01-01

Electronic enclosure design and the internal arrangement of PCBs and components influence microclimate inside the enclosure. This work features a general electronic unit with parallel PCBs. One of the PCB is considered to have heat generating components on it. The humidity and temperature profiles...... geometry of the device and related enclosure design parameters on the humidity and temperature profiles inside the electronic device enclosure....

30 CFR 56.12026 - Grounding transformer and switchgear enclosures.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding transformer and switchgear enclosures... MINES Electricity § 56.12026 Grounding transformer and switchgear enclosures. Metal fencing and metal buildings enclosing transformers and switchgear shall be grounded. ...

Natural convection in asymmetric triangular enclosures heated from below

International Nuclear Information System (INIS)

Kamiyo, O M; Angeli, D; Enzo Ferrari, Universita di Modena e Reggio Emilia, via Vignolese 905, I-41125 Modena (Italy))" data-affiliation=" (DIEF – Dipartimento di Ingegneria Enzo Ferrari, Universita di Modena e Reggio Emilia, via Vignolese 905, I-41125 Modena (Italy))" >Barozzi, G S; Collins, M W

2014-01-01

Triangular enclosures are typical configurations of attic spaces found in residential as well as industrial pitched-roof buildings. Natural convection in triangular rooftops has received considerable attention over the years, mainly on right-angled and isosceles enclosures. In this paper, a finite volume CFD package is employed to study the laminar air flow and temperature distribution in asymmetric rooftop-shaped triangular enclosures when heated isothermally from the base wall, for aspect ratios (AR) 0.2 ≤ AR ≤ 1.0, and Rayleigh number (Ra) values 8 × 10 5 ≤ Ra ≤ 5 × 10 7 . The effects of Rayleigh number and pitch angle on the flow structure and temperature distributions within the enclosure are analysed. Results indicate that, at low pitch angle, the heat transfer between the cold inclined and the hot base walls is very high, resulting in a multi-cellular flow structure. As the pitch angle increases, however, the number of cells reduces, and the total heat transfer rate progressively reduces, even if the Rayleigh number, being based on the enclosure height, rapidly increases. Physical reasons for the above effect are inspected

Natural convection heat transfer from a horizontal wavy surface in a porous enclosure

International Nuclear Information System (INIS)

Murthy, P.V.S.N.; Kumar, B.V.R.; Singh, P.

1997-01-01

The effect of surface undulations on the natural convection heat transfer from an isothermal surface in a Darcian fluid-saturated porous enclosure has been numerically analyzed using the finite element method on a graded nonuniform mesh system. The flow-driving Rayleigh number Ra together with the geometrical parameters of wave amplitude a, wave phase φ, and the number of waves N considered in the horizontal dimension of the cavity are found to influence the flow and heat transfer process in the enclosure. For Ra around 50 and above, the phenomenon of flow separation and reattachment is noticed on the walls of the enclosure. A periodic shift in the reattachment point from the bottom wall to the adjacent walls in the clockwise direction, leading to the manifestation of cycles of unicellular and bicellular clockwise and counterclockwise flows, is observed, with the phase varying between 0 degree and 350 degree. The counterflow in the secondary circulation zone is intensified with the increase in the value of Ra. The counterflow on the wavy wall hinders the heat transfer into the system. An increase in either wave amplitude or the number of waves considered per unit length decreases the global heat flux into the system. Only marginal changes in global heat flux are noticed with increasing Ra. On the whole, the comparison of global heat flux results in the wavy wall case with those of the horizontal flat wall case shows that, in a porous enclosure, the wavy wall reduces the heat transfer into the system

Explosion hazards of LPG-air mixtures in vented enclosure with obstacles.

Science.gov (United States)

Zhang, Qi; Wang, Yaxing; Lian, Zhen

2017-07-15

Numerical simulations were performed to study explosion characteristics of liquefied petroleum gas (LPG) explosion in enclosure with a vent. Unlike explosion overpressure and dynamic pressure, explosion temperature of the LPG-air mixture at a given concentration in a vented enclosure has very little variation with obstacle numbers for a given blockage ratio. For an enclosure without obstacle, explosion overpressures for the stoichiometric mixtures and the fuel-lean mixtures reach their maximum within the vent and that for fuel-rich mixture reaches its maximum beyond and near the vent. Dynamic pressures produced by an indoor LPG explosion reach their maximum always beyond the vent no matter obstacles are present or not in the enclosure. A LPG explosion in a vented enclosure with built-in obstacles is strong enough to make the brick and mortar wall with a thickness of 370mm damaged. If there is no obstacle in the enclosure, the lower explosion pressure of several kPa can not break the brick and mortar wall with a thickness of 370mm. For a LPG explosion produced in an enclosure with a vent, main hazards, within the vent, are overpressure and high temperature. However main hazards are dynamic pressure, blast wind, and high temperature beyond the vent. Copyright © 2017 Elsevier B.V. All rights reserved.

Large fully retractable telescope enclosures still closable in strong wind

Science.gov (United States)

Bettonvil, Felix C. M.; Hammerschlag, Robert H.; Jägers, Aswin P. L.; Sliepen, Guus

2008-07-01

Two prototypes of fully retractable enclosures with diameters of 7 and 9 m have been built for the high-resolution solar telescopes DOT (Dutch Open Telescope) and GREGOR, both located at the Canary Islands. These enclosures protect the instruments for bad weather and are fully open when the telescopes are in operation. The telescopes and enclosures also operate in hard wind. The prototypes are based on tensioned membrane between movable but stiff bows, which fold together to a ring when opened. The height of the ring is small. The prototypes already survived several storms, with often snow and ice, without any damage, including hurricane Delta with wind speeds up to 68 m/s. The enclosures can still be closed and opened with wind speeds of 20 m/s without any problems or restrictions. The DOT successfully demonstrated the open, wind-flushing concept for astronomical telescopes. It is now widely recognized that also large future telescopes benefit from wind-flushing and retractable enclosures. These telescopes require enclosures with diameters of 30 m until roughly 100 m, the largest sizes for the ELTs (Extreme Large Telescopes), which will be built in the near future. We discuss developments and required technology for the realization of these large sizes.

30 CFR 57.12026 - Grounding transformer and switchgear enclosures.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Grounding transformer and switchgear enclosures... NONMETAL MINES Electricity Surface and Underground § 57.12026 Grounding transformer and switchgear enclosures. Metal fencing and metal buildings enclosing transformers and switchgear shall be grounded. ...

Enclosure for handling high activity materials abstract

International Nuclear Information System (INIS)

Jimeno de Osso, F.; Dominguez Rodriguez, G.; Cruz Castillo, F. de la; Rodriguez Esteban, A.

1977-01-01

One of the most important problems that are met at the laboratories producing and handling radioisotopes is that of designing, building and operating enclosures suitable for the safe handling of active substances. With that purpose in mind, an enclosure has been designed and built for handling moderately high activities under a shielding made of 150 mm thick lead. A description is given of those aspects that may be of interest to people working in this field. (author) [es

Knowledge Enclosures, Forced Specializations and Investment Crisis

Directory of Open Access Journals (Sweden)

Filippo Belloc

2012-12-01

Full Text Available Like land before the industrial revolution, in the present global economy much knowledge is being enclosed in private hands. In this paper we argue that these enclosures have become a major factor in specialization among firms and among countries: both are forced to specialize in the fields that are not restricted by the enclosures of the others. We use data on 26 OECD countries over the 1978-2006 period. We estimate the effect of patents endowments of countries on their investment specialization across sectors and show that knowledge enclosures involve self-reinforcing innovation patterns. Moreover, we perform a structural change analysis and find that the TRIPs agreement has significantly strengthened the relationship between countries' patents specialization and investment specialization. We conclude by suggesting that stronger international patent protection may restrict global investment opportunities, and this may be one of the factors contributing to the present crisis.

Theoretical Characterization of Enclosures

Czech Academy of Sciences Publication Activity Database

Rohn, Jiří

2016-01-01

Roč. 21, October (2016), s. 140-145 ISSN 1573-1340 Institutional support: RVO:67985807 Keywords : interval linear equations * solution set * enclosure * component * characterization Subject RIV: BA - General Mathematics http://interval.louisiana.edu/reliable-computing-journal/volume-21/reliable-computing-21-pp-140-145.pdf

40 CFR 86.1217-96 - Evaporative emission enclosure calibrations.

Science.gov (United States)

2010-07-01

... procedure: (1) Carefully measure the internal length, width and height of the enclosure, accounting for... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Evaporative emission enclosure calibrations. 86.1217-96 Section 86.1217-96 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...

Multi-loop positivity of the planar N=4 SYM six-point amplitude

Energy Technology Data Exchange (ETDEWEB)

Dixon, Lance J. [SLAC National Accelerator Laboratory,Stanford University, Stanford, CA 94309 (United States); Hippel, Matt von [Perimeter Institute for Theoretical Physics,Waterloo, Ontario N2L 2Y5 (Canada); McLeod, Andrew J. [SLAC National Accelerator Laboratory,Stanford University, Stanford, CA 94309 (United States); Trnka, Jaroslav [Center for Quantum Mathematics and Physics (QMAP),Department of Physics, University of California, Davis, CA 95616 (United States)

2017-02-22

We study the six-point NMHV ratio function in planar N=4 SYM theory in the context of positive geometry. The Amplituhedron construction of the integrand for the amplitudes provides a kinematical region in which the integrand was observed to be positive. It is natural to conjecture that this property survives integration, i.e. that the final result for the ratio function is also positive in this region. Establishing such a result would imply that preserving positivity is a surprising property of the Minkowski contour of integration and it might indicate some deeper underlying structure. We find that the ratio function is positive everywhere we have tested it, including analytic results for special kinematical regions at one and two loops, as well as robust numerical evidence through five loops. There is also evidence for not just positivity, but monotonicity in a “radial” direction. We also investigate positivity of the MHV six-gluon amplitude. While the remainder function ceases to be positive at four loops, the BDS-like normalized MHV amplitude appears to be positive through five loops.

Sound reduction by metamaterial-based acoustic enclosure

Directory of Open Access Journals (Sweden)

Shanshan Yao

2014-12-01

Full Text Available In many practical systems, acoustic radiation control on noise sources contained within a finite volume by an acoustic enclosure is of great importance, but difficult to be accomplished at low frequencies due to the enhanced acoustic-structure interaction. In this work, we propose to use acoustic metamaterials as the enclosure to efficiently reduce sound radiation at their negative-mass frequencies. Based on a circularly-shaped metamaterial model, sound radiation properties by either central or eccentric sources are analyzed by numerical simulations for structured metamaterials. The parametric analyses demonstrate that the barrier thickness, the cavity size, the source type, and the eccentricity of the source have a profound effect on the sound reduction. It is found that increasing the thickness of the metamaterial barrier is an efficient approach to achieve large sound reduction over the negative-mass frequencies. These results are helpful in designing highly efficient acoustic enclosures for blockage of sound in low frequencies.

Sound reduction by metamaterial-based acoustic enclosure

Energy Technology Data Exchange (ETDEWEB)

Yao, Shanshan; Li, Pei; Zhou, Xiaoming; Hu, Gengkai, E-mail: hugeng@bit.edu.cn [Key Laboratory of Dynamics and Control of Flight Vehicle, Ministry of Education and School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081 (China)

2014-12-15

In many practical systems, acoustic radiation control on noise sources contained within a finite volume by an acoustic enclosure is of great importance, but difficult to be accomplished at low frequencies due to the enhanced acoustic-structure interaction. In this work, we propose to use acoustic metamaterials as the enclosure to efficiently reduce sound radiation at their negative-mass frequencies. Based on a circularly-shaped metamaterial model, sound radiation properties by either central or eccentric sources are analyzed by numerical simulations for structured metamaterials. The parametric analyses demonstrate that the barrier thickness, the cavity size, the source type, and the eccentricity of the source have a profound effect on the sound reduction. It is found that increasing the thickness of the metamaterial barrier is an efficient approach to achieve large sound reduction over the negative-mass frequencies. These results are helpful in designing highly efficient acoustic enclosures for blockage of sound in low frequencies.

A Numerical Study of Fluid Flow and Heat Transfer in Carbon Dioxide Enclosures on Mars

Directory of Open Access Journals (Sweden)

Yue Sun

2018-03-01

Full Text Available In order to support the future thermal control and energy conservation design for the Mars rover, numerical studies on natural convection in CO2 enclosures on Mars’ surface were conducted for both horizontal and vertical enclosures. The parameters are as follows: the atmospheric pressure was 1000 Pa, the gravitational acceleration was 3.62 m/s2, and the Prandtl number was 0.77. The heat flux, temperature, and velocity fields of the CO2 enclosures were obtained with the aspect ratio ranging from 5.56 to 200 and the Grashof number ranging from 430 to 2.6 × 104. It was found that natural convection formed more easily in the horizontal enclosures than that in the vertical enclosures when the enclosures had same thickness. With the increasing thickness of the enclosures, Rayleigh–Bénard convections formed in the horizontal enclosures, while only single-cell convections formed in the vertical enclosures. The heat flux through the horizontal enclosures was greater than that through the vertical enclosures with the same thickness when natural convection formed. The maximum difference between them reached 35.26%, which was illustrated by the field synergy principle. A hysteresis phenomenon of the natural convection dominating the heat transfer was found in the vertical enclosure on Mars’ surface. New values for the critical Grashof number and correlations for the average Nusselt number for both the horizontal and vertical CO2 enclosures on Mars’ surface were also developed.

Yangian-type symmetries of non-planar leading singularities

Energy Technology Data Exchange (ETDEWEB)

Frassek, Rouven [Department of Mathematical Sciences, Durham University,South Road, Durham DH1 3LE (United Kingdom); Meidinger, David [Institut für Mathematik und Institut für Physik, Humboldt-Universität zu Berlin,Zum Großen Windkanal 6, 12489 Berlin (Germany)

2016-05-18

We take up the study of integrable structures behind non-planar contributions to scattering amplitudes in N = 4 super Yang-Mills theory. Focusing on leading singularities, we derive the action of the Yangian generators on color-ordered subsets of the external states. Each subset corresponds to a single boundary of the non-planar on-shell diagram. While Yangian invariance is broken, we find that higher-level Yangian generators still annihilate the non-planar on-shell diagram. For a given diagram, the number of these generators is governed by the degree of non-planarity. Furthermore, we present additional identities involving integrable transfer matrices. In particular, for diagrams on a cylinder we obtain a conservation rule similar to the Yangian invariance condition of planar on-shell diagrams. To exemplify our results, we consider a five-point MHV on-shell function on a cylinder.

46 CFR 154.195 - Aluminum cargo tank: Steel enclosure.

Science.gov (United States)

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Aluminum cargo tank: Steel enclosure. 154.195 Section... Equipment Hull Structure § 154.195 Aluminum cargo tank: Steel enclosure. (a) An aluminum cargo tank and its... the aluminum cargo tank must meet the steel structural standards of the American Bureau of Shipping...

An architecture for integrating planar and 3D cQED devices

Energy Technology Data Exchange (ETDEWEB)

Axline, C.; Reagor, M.; Heeres, R.; Reinhold, P.; Wang, C.; Shain, K.; Pfaff, W.; Chu, Y.; Frunzio, L.; Schoelkopf, R. J. [Department of Applied Physics, Yale University, New Haven, Connecticut 06511 (United States)

2016-07-25

Numerous loss mechanisms can limit coherence and scalability of planar and 3D-based circuit quantum electrodynamics (cQED) devices, particularly due to their packaging. The low loss and natural isolation of 3D enclosures make them good candidates for coherent scaling. We introduce a coaxial transmission line device architecture with coherence similar to traditional 3D cQED systems. Measurements demonstrate well-controlled external and on-chip couplings, a spectrum absent of cross-talk or spurious modes, and excellent resonator and qubit lifetimes. We integrate a resonator-qubit system in this architecture with a seamless 3D cavity, and separately pattern a qubit, readout resonator, Purcell filter, and high-Q stripline resonator on a single chip. Device coherence and its ease of integration make this a promising tool for complex experiments.

Numerical Simulation of Transient Moisture Transfer into an Electronic Enclosure

DEFF Research Database (Denmark)

Shojaee Nasirabadi, Parizad; Jabbaribehnam, Mirmasoud; Hattel, Jesper Henri

2016-01-01

Electronic systems are sometimes exposed to harsh environmental conditions of temperature and humidity. Moisturetransfer into electronic enclosures and condensation can cause several problems such as corrosion and alteration in thermalstresses. It is therefore essential to study the local climate...... inside the enclosures to be able to protect the electronic systems.In this work, moisture transfer into a typical electronic enclosure is numerically studied using CFD. In order to reduce theCPU-time and make a way for subsequent factorial design analysis, a simplifying modification is applied in which...

49 CFR 193.2905 - Protective enclosures.

Science.gov (United States)

2010-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY LIQUEFIED NATURAL GAS FACILITIES... surrounded by a protective enclosure: (1) Storage tanks; (2) Impounding systems; (3) Vapor barriers; (4...

Test plan for engineering scale electrostatic enclosure demonstration

International Nuclear Information System (INIS)

Meyer, L.C.

1993-02-01

This test plan describes experimental details of an engineering-scale electrostatic enclosure demonstration to be performed at the Idaho National Engineering Laboratory in fiscal year (FY)-93. This demonstration will investigate, in the engineering scale, the feasibility of using electrostatic enclosures and devices to control the spread of contaminants during transuranic waste handling operations. Test objectives, detailed experimental procedures, and data quality objectives necessary to perform the FY-93 experiments are included in this plan

Effects of Power Lines on Area Use and Behaviour of Semi-Domestic Reindeer in Enclosures

International Nuclear Information System (INIS)

Flydal, K.; Reimers, E.; Johansen, F.; Colman, J.E.; Korslund, L.; Colman, J.E.

2009-01-01

We conducted large-scale, replicated experiments to test the effects of two parallel power lines on area use, behaviour, and activity of semidomestic reindeer in enclosures. Yearling female reindeer were released into four 50 x 400 m enclosures; two treatment enclosures with power lines and two control enclosures. Reindeer from two herds, one from Kautokeino (domestic tame) and one from Vaga, (domestic wild) were tested separately and compared. Individual location within the enclosures was not affected by the power lines. Effects on restless behaviour were ambiguous, with slightly more restless behaviour in the treatment enclosures for the domestic tame reindeer, while the domestic wild reindeer maintained a stable level in the treatment enclosures, increasing with time in the control enclosures. Activity changes were slightly more common among animals within treatment enclosures for both herds, with no indication of habituation during the experiment. The domestic wild reindeer had more than three times the amount of restless behaviour than the domestic tame reindeer. Our study indicates that for reindeer in enclosures, the disturbance from a power line construction is negligible. This suggests that power lines are a minor disturbing factor compared to human handling when using fenced in areas like grazing gardens in reindeer husbandry.

Construction of Lightweight Loudspeaker Enclosures

DEFF Research Database (Denmark)

Juul-Nyholm, Herle Bagh; Severinsen, Jonas Corfitz; Schneider, Henrik

2017-01-01

On the basis of bass cabinets, this paper deals with the problem of reducing loudspeaker enclosure weight. An introductory market analysis emphasizes that lighter cabinets are sought, but maintenance of sound quality is vital. The problem is challenged through experiments and simulations in COMSO...

Reactor enclosure. BRC meeting presentation

International Nuclear Information System (INIS)

Fisch, J.W.

1975-01-01

The latest status of key components of the Reactor Enclosure System of the Clinch River Breeder Reactor Plant is described. Areas where there have been notable design changes or significant design detail maturity in the six months since the last BRC presentation are highlighted. (auth)

The simple method to co-register planar image with photograph

International Nuclear Information System (INIS)

Jang, Sung June; Kim, Seok Ki; Kang, Keon Wook

2005-01-01

Generally scintigraphic image presents the highly specific functional information. Sometimes, there can be limited information of patients anatomical landmark required to identify the lesion in planar nuclear medicine image. In this study, we applied the simple fusion method of planar scintigraphy and plain photography and validated the techniques with our own software. We used three fiducial marks which were comprised with Tc-99m. We obtained planar image with single head gamma camera (ARGUS ADAC laboratory, USA) and photograph using a general digital camera (CANON JAPAN). The coordinates of three marks were obtained in photograph and planar scintigraphy image. Based on these points, we took affine transformation and then fused these two images. To evaluate the precision, we compared with different depth. To find out the depth of lesion, the images were acquired in different angles and we compared the real depth and the geometrically calculated depth. At the same depth with mark, the each discordance was less than 1 mm. When the photograph were taken at the distance with 1 m and 2 m, the point 30 cm off the center were discordant in 5 mm and 2 mm each. We used this method in the localization of the remnant thyroid tissue on I-131 whole body scan with photo image. The simple method to co-register planar image with photography was reliable and easy to use. By this method, we could localize the lesion on the planar scintigraphy more accurately with other planar images (i.e. photograph) and predict the depth of the lesion without tomographic image

Integrated thermal control and system assessment in plug-chip spray cooling enclosure

International Nuclear Information System (INIS)

Zhang, Wei-Wei; Cheng, Wen-Long; Shao, Shi-Dong; Jiang, Li-Jia; Hong, Da-Liang

2016-01-01

Highlights: • A novel multi-heat source plug-chip spray cooling enclosure was designed. • Enhanced surfaces with different geometric were analyzed in integrated enclosure. • Overall thermal control with adjustable parameters in enclosure was studied. • Temperature disequilibrium of multi-heat source in enclosure was tested. • A comprehensive assessment system used to evaluate the practicality was proposed. - Abstract: Practical and integrated spray cooling system is urgently needed for the cooling of high-performance electronic chips due to the growth requirements of thermal management in workstation. The integration of multi heat sources and the management of integral system are particularly lacking. In order to fill the vacancies in the study of plug-chip spray cooling, an integrated cooling enclosure was designed in this paper. Multi heat sources were placed in sealed space and the heat was removed by spray. The printed circuit board plug-ins and radio frequency resistors were used as analog motherboards and chips, respectively. The enhanced surfaces with four different geometries and the plain surface were studied under the conditions of different inclination angles. The results were compared and the maximum critical heat flux (CHF) was obtained. Moreover, with the intention of the overall management of multi-heat source in integrated enclosure, the effect of the flow rate and the temperature disequilibrium, and the pulse heating in the process of transient cooling were also analyzed. In addition, a comprehensive assessment system, used to evaluate the practicality of spray cooling experimental devices, was proposed and the performance of enclosure was evaluated.

Dynamic Planar Convex Hull

DEFF Research Database (Denmark)

Jacob, Riko

We determine the computational complexity of the dynamic convex hull problem in the planar case. We present a data structure that maintains a finite set of n points in the plane under insertion and deletion of points in amortized O(log n) time per operation. The space usage of the data structure...... is O(n). The data structure supports extreme point queries in a given direction, tangent queries through a given point, and queries for the neighboring points on the convex hull in O(log n) time. The extreme point queries can be used to decide whether or not a given line intersects the convex hull......, and the tangent queries to determine whether a given point is inside the convex hull. The space usage of the data structure is O(n). We give a lower bound on the amortized asymptotic time complexity that matches the performance of this data structure....

Manual on shielded enclosures. Incorporating: Applications guide, procedures guide, basics guide

International Nuclear Information System (INIS)

1992-01-01

This booklet contains a basic guide to the principles of the production of ionizing radiation and to methods of radiation protection and dosimetry, and a discussion of the need for shielded enclosures. Shielding materials and the design of the enclosures are described

Humidity Buildup in Electronic Enclosures Exposed to Constant Conditions

DEFF Research Database (Denmark)

Conseil, Helene; Staliulionis, Zygimantas; Jellesen, Morten Stendahl

2017-01-01

Electronic components and devices are exposed to a wide variety of climatic conditions, therefore the protection of electronic devices from humidity is becoming a critical factor in the system design. The ingress of moisture into typical electronic enclosures has been studied with defined paramet....... The moisture buildup inside the enclosure has been simulated using an equivalent RC circuit consisting of variables like controlled resistors and capacitors to describe the diffusivity, permeability, and storage in polymers....

Cumulative effects, creeping enclosure, and the marine commons of New Jersey

Directory of Open Access Journals (Sweden)

Grant Murray

2010-02-01

Full Text Available In response to declining fish stocks and increased societal concern, the marine ‘commons’ of New Jersey is no longer freely available to commercial and recreational fisheries. We discuss the concept of ‘creeping’ enclosure in relation to New Jersey’s marine fisheries and suggest that reduced access can be a cumulative process and function of multiple events and processes and need not be the result of a single regulatory moment. We begin with a short review of the ‘expected’ effects of enclosure, including loss of flexibility, erosion of community, proletarianization of fishermen, and corporatization of the fishery. We then present some findings of our research and discuss how the signs of enclosure are visible in fisheries that do not feature explicitly privatized property or access rights. We rely on an oral history approach and the rich detail that emerges from attention to the lived experiences of fish harvesters to provide a framework for understanding the range of cumulative effects that have resulted from this process of creeping enclosure. We conclude with a discussion of how the gradual process of enclosure has affected the flows of information between the bio-physical environment and fish harvesters, managers and scientists by reducing both participation in fisheries and the accumulation of knowledge itself.

Oxygen ingress study of 3D printed gaseous radiation detector enclosures

Energy Technology Data Exchange (ETDEWEB)

Steer, Christopher A.; Durose, Aaron [AWE, Alderrnaston, Reading, Berkshire, RG7 4PR (United Kingdom)

2015-07-01

As part of our ongoing studies into the potential application of 3D printing techniques to gaseous radiation detectors, we have studied the ability of 3D printed enclosures to resist environmental oxygen ingress. A set of cuboid and hexagonal prism shaped enclosures with wall thicknesses of 4 mm, 6 mm, 8 mm and 10 mm were designed and printed in nylon using a EOSINT P 730 Selective Laser Sintering 3D printer system These test enclosures provide a comparison of different environmental gas ingress for different 3D printing techniques. The rate of change of oxygen concentration was found to be linear, decreasing as the wall thickness increases. It was also found that the hexagonal prism geometry produced a lower rate of change of oxygen concentration compared with the cuboid shaped enclosures. Possible reasons as to why these results were obtained are discussed The implications for the this study for deployable systems are also discussed (authors)

Oxygen ingress study of 3D printed gaseous radiation detector enclosures

International Nuclear Information System (INIS)

Steer, Christopher A.; Durose, Aaron

2015-01-01

As part of our ongoing studies into the potential application of 3D printing techniques to gaseous radiation detectors, we have studied the ability of 3D printed enclosures to resist environmental oxygen ingress. A set of cuboid and hexagonal prism shaped enclosures with wall thicknesses of 4 mm, 6 mm, 8 mm and 10 mm were designed and printed in nylon using a EOSINT P 730 Selective Laser Sintering 3D printer system These test enclosures provide a comparison of different environmental gas ingress for different 3D printing techniques. The rate of change of oxygen concentration was found to be linear, decreasing as the wall thickness increases. It was also found that the hexagonal prism geometry produced a lower rate of change of oxygen concentration compared with the cuboid shaped enclosures. Possible reasons as to why these results were obtained are discussed The implications for the this study for deployable systems are also discussed (authors)

55-68 Impact of Area Enclosures on Density and Diversity of Large ...

African Journals Online (AJOL)

1Department of Land Resources Management and Environmental Protection, Mekelle University, ... The enclosures have higher density and diversity of large wild mammals ..... in it. Figure 4 Human interference in enclosures of the study area ...

Design, construction and testing of a DC bioeffects test enclosure for small animals. Final report

Energy Technology Data Exchange (ETDEWEB)

Frazier, M J; Preache, M M

1980-11-01

This final report describes both the engineering development of a DC bioeffects test enclosure for small laboratory animals, and the biological protocol for the use of such enclosures in the testing of animals to determine possible biological effects of the environment associated with HVDC transmission lines. The test enclosure which has been designed is a modular unit, which will house up to eight rat-sized animals in individual compartments. Multiple test enclosures can be used to test larger numbers of animals. A prototype test enclosure has been fabricated and tested to characterize its electrical performance characteristics. The test enclosure provides a simulation of the dominant environment associated with HVDC transmission lines; namely, a static electric field and an ion current density. A biological experimental design has been developed for assessing the effects of the dominant components of the HVDC transmission line environment.

Investigations into the dynamics of aerosols in enclosures as used for air pollution studies

International Nuclear Information System (INIS)

Vate, J.F. van de.

1980-07-01

The author treats aerosol behaviour under various conditions in enclosed spaces. A model is given describing aerosol removal from enclosed spaces; boundary conditions are given for non-stirred deposition of aerosols by sedimentation and diffusion. Experimental results are presented for unheated dry enclosures, heated dry enclosures, enclosures with a heated pool of liquid, and smog chambers. (G.T.H.)

Enclosure design for flock-level, chronic exposure of birds to air contaminant mixtures.

Science.gov (United States)

North, Michelle A; Kinniburgh, David W; Smits, Judit E G

2018-05-01

The objective of this study was to design an enclosure suitable for studying the ecotoxicological effects of vehicle emissions on groups of wild birds without compromising welfare. Two, adjacent enclosures sheltered from sunlight, wind and rain, were bird-proofed and wrapped with thick polyethylene sheeting. Emissions were directed into the treatment enclosure from the exhaust of a light-duty gasoline truck, using flexible, heat-proof pipe, with joins sealed to prevent leakage. During active exposure, the engine was idled for 5 h/day, 6 days/week for 4 weeks. Fans maintained positive pressure (controls) and negative pressure (treatment), preventing cross-contamination of enclosures and protecting investigators. Four sets of passive, badge-type samplers were distributed across each enclosure, measuring nitrogen dioxide, sulfur dioxide and volatile organic compounds (NO 2 , SO 2 and VOCs, respectively), and were complemented by active monitors measuring VOCs and particulate matter (2.5 µm diameter, PM 2.5 ). We found that the concentrations of NO 2 , SO 2 and PM 2.5 were not different between treatment and control enclosures. Volatile organic compounds (e.g. benzene, toluene, ethylbenzene and xylenes) were approximately six times higher in the treatment enclosure than control (13.23 and 2.13 µg m -1 , respectively). In conclusion, this represents a successful, practical design for studying the effects of sub-chronic to chronic exposure to realistic mixtures of vehicle exhaust contaminants, in groups of birds. Recommended modifications for future research include a chassis dynamometer (vehicle treadmill), to better replicate driving conditions including acceleration and deceleration.

50 CFR 14.161 - Primary enclosures.

Science.gov (United States)

2010-10-01

... Wild Mammals and Birds to the United States Specifications for Other Terrestrial Mammals § 14.161... primary enclosure shall provide adequate space for the animal to stand upright in a normal posture with... lie in a full prone position. Specifications for Birds ...

Aerothermodynamic properties of stretched flames in enclosures

Science.gov (United States)

Rotman, D. A.; Oppenheim, A. K.

Flames are stretched by being pulled along their frontal surface by the flow field in which they reside. Their trajectories tend to approach particle paths, acquiring eventually the role of contact boundaries, -interfaces between the burnt and unburnt medium that may broaden solely as a consequence of diffusion. Fundamental properties of flow fields governing such flames are determined here on the basis of the zero Mach number model, providng a rational method of approach to the computational analysis of combustion fields in enclosures where, besides the aerodynamic properties flow, the thermodynamic process of compression must be taken into account. To illustrate its application, the method is used to reveal the mechanism of formation of a tulip-shape flame in a rectangular enclosure under nonturbulent flow conditions.

Constructal design of phase change material enclosures used for cooling electronic devices

International Nuclear Information System (INIS)

Kalbasi, Rasool; Salimpour, Mohammad Reza

2015-01-01

Recent developments in cooling methods for portable electronic devices have heightened the need for using the large latent heat capacity of phase change materials (PCM). The aim of the present study is to evaluate the thermal characteristics of a PCM-based heat sink with high conductive materials. The solution is acquired as a procession of optimization stages which starts with the elemental area and proceeds toward the first assembly. Every optimization stage is the result of maximizing the safe operation time without allowing the electronics to reach the critical temperature. Primarily, the degrees of freedom and constrains were defined and then by changing the geometrical parameters, the target function which is the maximization of operation time, was optimized. Results show that the melting process in rectangular enclosures with vertical fins attached to the heated bottom surface can be affected by the contact surface between the fin and PCM and the convection of the melted PCM. For a rectangular enclosure with a constant area, it is better to use wider enclosure than the square and thin one. Also results indicate that the ratio of the vertical fin thickness to the horizontal one does not have a considerable effect on performance. By increasing the number of enclosures, the contact surface is raised, but the performance is not necessarily improved. - Highlights: • Thermal characteristics of a finned PCM-based heat sink are studied. • Constructal theory was used to optimize the PCM enclosures. • By increasing the number of enclosures, the performance is not necessarily improved

9 CFR 3.6 - Primary enclosures.

Science.gov (United States)

2010-01-01

... coated with a material such as plastic or fiberglass. The suspended floor of any primary enclosure must... and behavioral characteristics, and in accordance with generally accepted husbandry practices. If the... characteristics, and in accordance with generally accepted husbandry practices as determined by the attending...

Geodesic distance in planar graphs

International Nuclear Information System (INIS)

Bouttier, J.; Di Francesco, P.; Guitter, E.

2003-01-01

We derive the exact generating function for planar maps (genus zero fatgraphs) with vertices of arbitrary even valence and with two marked points at a fixed geodesic distance. This is done in a purely combinatorial way based on a bijection with decorated trees, leading to a recursion relation on the geodesic distance. The latter is solved exactly in terms of discrete soliton-like expressions, suggesting an underlying integrable structure. We extract from this solution the fractal dimensions at the various (multi)-critical points, as well as the precise scaling forms of the continuum two-point functions and the probability distributions for the geodesic distance in (multi)-critical random surfaces. The two-point functions are shown to obey differential equations involving the residues of the KdV hierarchy

Numerical simulation of transient moisture transfer into an electronic enclosure

Energy Technology Data Exchange (ETDEWEB)

Nasirabadi, P. Shojaee; Jabbari, M.; Hattel, J. H. [Process Modelling Group, Department of Mechanical Engineering, Technical University of Denmark, Nils Koppels Allé, 2800 Kgs. Lyngby (Denmark)

2016-06-08

Electronic systems are sometimes exposed to harsh environmental conditions of temperature and humidity. Moisture transfer into electronic enclosures and condensation can cause several problems such as corrosion and alteration in thermal stresses. It is therefore essential to study the local climate inside the enclosures to be able to protect the electronic systems. In this work, moisture transfer into a typical electronic enclosure is numerically studied using CFD. In order to reduce the CPU-time and make a way for subsequent factorial design analysis, a simplifying modification is applied in which the real 3D geometry is approximated by a 2D axial symmetry one. The results for 2D and 3D models were compared in order to calibrate the 2D representation. Furthermore, simulation results were compared with experimental data and good agreement was found.

Numerical simulation of transient moisture transfer into an electronic enclosure

International Nuclear Information System (INIS)

Nasirabadi, P. Shojaee; Jabbari, M.; Hattel, J. H.

2016-01-01

Electronic systems are sometimes exposed to harsh environmental conditions of temperature and humidity. Moisture transfer into electronic enclosures and condensation can cause several problems such as corrosion and alteration in thermal stresses. It is therefore essential to study the local climate inside the enclosures to be able to protect the electronic systems. In this work, moisture transfer into a typical electronic enclosure is numerically studied using CFD. In order to reduce the CPU-time and make a way for subsequent factorial design analysis, a simplifying modification is applied in which the real 3D geometry is approximated by a 2D axial symmetry one. The results for 2D and 3D models were compared in order to calibrate the 2D representation. Furthermore, simulation results were compared with experimental data and good agreement was found.

Laying hen movement in a commercial aviary: Enclosure to floor and back again.

Science.gov (United States)

Campbell, D L M; Makagon, M M; Swanson, J C; Siegford, J M

2016-01-01

Many producers in the laying hen industry, including in North America, are phasing out conventional cages in response to consumer demands and sometimes subsequent legislation. Alternative housing systems such as aviaries are being implemented in an attempt to improve hen welfare. Aviaries provide additional space and resources to groups of hens, including a litter area on the floor. However, little is known about hen movement between tiered enclosures and floor litter areas in aviary systems. Diurnal rhythms and social attraction may result in peak times of movement that could lead to overcrowding of areas, or alternatively hen preferences may lead to some areas not being fully utilized. We monitored hen movement between tiered enclosures and litter areas, including movement on and off the outer perch, across the day at peak, mid and end of lay in a commercial aviary. Hens moved onto and off of the open litter area across the day, transitioning between tiered enclosures, outer perches, open litter areas, and litter areas under tiered enclosures. At certain times of day, there were periods of greater hen movement down to the open litter area and between litter areas. For example, more hens were typically observed exiting enclosures, jumping from perches to open litter, and traveling between open litter and litter under tiered enclosures in the morning (all P ≤ 0.001). In all but one instance, more hens were observed on open litter areas in the afternoon than at other times of day (all P ≤ 0.029). However, hen re-entry to tiered enclosures showed less circadian patterning. Hen movement was observed between areas of interest at all sampled time periods, indicating hens use all areas of the system. Further research should examine whether all individual hens do move between areas equally, including within levels of the tiered enclosure, or if crowding occurs on the outer perches or in the litter during times of peak movement. © 2015 Poultry Science Association Inc.

Apparatus for posting materials into and out of enclosures

International Nuclear Information System (INIS)

Sperinck, W.A.; Ashcroft, K.C.

1986-01-01

The patent concerns an apparatus for posting toxic or radioactive materials into and out of a high integrity enclosure, such as a glovebox, through a port in a wall of the enclosure. The apparatus comprises a container for the materials, with a lid which is engageable with a door for the port, and the container is supported in a cradle. The door cannot be opened in the absence of a container in the cradle, and the container cannot be removed when the door and lid unit is away from the port. (UK)

General point dipole theory for periodic metasurfaces: magnetoelectric scattering lattices coupled to planar photonic structures.

Science.gov (United States)

Chen, Yuntian; Zhang, Yan; Femius Koenderink, A

2017-09-04

We study semi-analytically the light emission and absorption properties of arbitrary stratified photonic structures with embedded two-dimensional magnetoelectric point scattering lattices, as used in recent plasmon-enhanced LEDs and solar cells. By employing dyadic Green's function for the layered structure in combination with the Ewald lattice summation to deal with the particle lattice, we develop an efficient method to study the coupling between planar 2D scattering lattices of plasmonic, or metamaterial point particles, coupled to layered structures. Using the 'array scanning method' we deal with localized sources. Firstly, we apply our method to light emission enhancement of dipole emitters in slab waveguides, mediated by plasmonic lattices. We benchmark the array scanning method against a reciprocity-based approach to find that the calculated radiative rate enhancement in k-space below the light cone shows excellent agreement. Secondly, we apply our method to study absorption-enhancement in thin-film solar cells mediated by periodic Ag nanoparticle arrays. Lastly, we study the emission distribution in k-space of a coupled waveguide-lattice system. In particular, we explore the dark mode excitation on the plasmonic lattice using the so-called array scanning method. Our method could be useful for simulating a broad range of complex nanophotonic structures, i.e., metasurfaces, plasmon-enhanced light emitting systems and photovoltaics.

Semantic data association for planar features in outdoor 6D-SLAM using lidar

Science.gov (United States)

Ulas, C.; Temeltas, H.

2013-05-01

Simultaneous Localization and Mapping (SLAM) is a fundamental problem of the autonomous systems in GPS (Global Navigation System) denied environments. The traditional probabilistic SLAM methods uses point features as landmarks and hold all the feature positions in their state vector in addition to the robot pose. The bottleneck of the point-feature based SLAM methods is the data association problem, which are mostly based on a statistical measure. The data association performance is very critical for a robust SLAM method since all the filtering strategies are applied after a known correspondence. For point-features, two different but very close landmarks in the same scene might be confused while giving the correspondence decision when their positions and error covariance matrix are solely taking into account. Instead of using the point features, planar features can be considered as an alternative landmark model in the SLAM problem to be able to provide a more consistent data association. Planes contain rich information for the solution of the data association problem and can be distinguished easily with respect to point features. In addition, planar maps are very compact since an environment has only very limited number of planar structures. The planar features does not have to be large structures like building wall or roofs; the small plane segments can also be used as landmarks like billboards, traffic posts and some part of the bridges in urban areas. In this paper, a probabilistic plane-feature extraction method from 3DLiDAR data and the data association based on the extracted semantic information of the planar features is introduced. The experimental results show that the semantic data association provides very satisfactory result in outdoor 6D-SLAM.

50 CFR 14.151 - Primary enclosures.

Science.gov (United States)

2010-10-01

... Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR TAKING... Wild Mammals and Birds to the United States Specifications for Sloths, Bats, and Flying Lemurs... located on the upper one-half of the primary enclosure. (b) No more than one sloth, bat, or flying lemur...

Radiant cooling of an enclosure

International Nuclear Information System (INIS)

Chebihi, Abdeslam; Byun, Ki-Hong; Wen Jin; Smith, Theodore F.

2006-01-01

The purpose of this study is to analyze the potential for radiant cooling using the atmospheric sky window and to evaluate the desired characteristics of a radiant cooling material (RCM) applied to the ceiling window of a three-dimensional enclosure. The thermal characteristics of the system are governed by the geometry, ambient temperature, sky radiative temperature, amount of solar energy and its direction, heat transfer modes, wall radiative properties, and radiative properties of the RCMs. A semi-gray band analysis is utilized for the solar and infrared bands. The radiosity/irradiation method is used in each band to evaluate the radiant exchanges in the enclosure. The radiative properties for the RCM are varied in a parametric study to identify the desired properties of RCMs. For performance simulation of real RCMs, the radiative properties are calculated from spectral data. The desired solar property is a high reflectance for both opaque and semi-transparent RCMs. For a semi-transparent RCM, a low value of the solar transmittance is preferred. The desired infrared property is a high emittance for an opaque RCM. For a semi-transparent RCM, a high infrared transmittance is desired, and the emittance should be greater than zero

ZFS on RBODs - Leveraging RAID Controllers for Metrics and Enclosure Management

Energy Technology Data Exchange (ETDEWEB)

Stearman, D. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-03-30

Traditionally, the Lustre file system has relied on the ldiskfs file system with reliable RAID (Redundant Array of Independent Disks) storage underneath. As of Lustre 2.4, ZFS was added as a backend file system, with built-in software RAID, thereby removing the need of expensive RAID controllers. ZFS was designed to work with JBOD (Just a Bunch Of Disks) storage enclosures under the Solaris Operating System, which provided a rich device management system. Long time users of the Lustre file system have relied on the RAID controllers to provide metrics and enclosure monitoring and management services, with rich APIs and command line interfaces. This paper will study a hybrid approach using an advanced full featured RAID enclosure which is presented to the host as a JBOD, This RBOD (RAIDed Bunch Of Disks) allows ZFS to do the RAID protection and error correction, while the RAID controller handles management of the disks and monitors the enclosure. It was hoped that the value of the RAID controller features would offset the additional cost, and that performance would not suffer in this mode. The test results revealed that the hybrid RBOD approach did suffer reduced performance.

ZFS on RBODs - Leveraging RAID Controllers for Metrics and Enclosure Management

International Nuclear Information System (INIS)

Stearman, D. M.

2015-01-01

Traditionally, the Lustre file system has relied on the ldiskfs file system with reliable RAID (Redundant Array of Independent Disks) storage underneath. As of Lustre 2.4, ZFS was added as a backend file system, with built-in software RAID, thereby removing the need of expensive RAID controllers. ZFS was designed to work with JBOD (Just a Bunch Of Disks) storage enclosures under the Solaris Operating System, which provided a rich device management system. Long time users of the Lustre file system have relied on the RAID controllers to provide metrics and enclosure monitoring and management services, with rich APIs and command line interfaces. This paper will study a hybrid approach using an advanced full featured RAID enclosure which is presented to the host as a JBOD, This RBOD (RAIDed Bunch Of Disks) allows ZFS to do the RAID protection and error correction, while the RAID controller handles management of the disks and monitors the enclosure. It was hoped that the value of the RAID controller features would offset the additional cost, and that performance would not suffer in this mode. The test results revealed that the hybrid RBOD approach did suffer reduced performance.

Effects of a new molt-inducing insecticide, tebufenozide, on zooplankton communities in lake enclosures.

Science.gov (United States)

Kreutzweiser, D P; Thomas, D R

1995-10-01

: A potent ecdysone agonist, tebufenozide, has recently been developed as a molt-inducing insecticide to control defoliating lepidopterans. As part of continuing research efforts to assess the effectiveness and environmental safety of this material for insect pest management in Canadian forests, tebufenozide (RH-5992-2F) was applied to large lake enclosures and the effects on zooplankton communities were evaluated. There were significant treatment effects at all test concentrations (0.07-0.66 mg L(-1) tebufenozide). Concentration-dependent reductions in the abundance of cladocerans indicated that there were direct toxic effects of tebufenozide on this group of macrozooplankton. There were no indications of direct toxic effects on copepods. Significant increases in abundance of rotifers in treated enclosures at the three higher test concentrations were coincident with reductions in cladocerans and indicated secondary effects of the insecticide on the abundance of microzooplankton. There were no significant differences among treated and control enclosures in chlorophyll a concentrations, indicating that tebufenozide did not have direct effects on phytoplankton biomass, nor did the alterations in the zooplankton communities of treated enclosures have measurable secondary effects on phytoplankton biomass. Daytime dissolved oxygen concentrations were significantly higher in treated enclosures than in controls, indicating that the perturbation to biotic communities of some treated enclosures was sufficient to induce measurable changes in system-level functional attributes. Recovery of zooplankton communities in the enclosures occurred within 1-2 months at 0.07 and 0.13 mg l(-1) and by the following summer (12-13 months) at 0.33 and 0.66 mg l(-1).

Impact resistant battery enclosure systems

Science.gov (United States)

Tsutsui, Waterloo; Feng, Yuezhong; Chen, Weinong Wayne; Siegmund, Thomas Heinrich

2017-10-31

Battery enclosure arrangements for a vehicular battery system. The arrangements, capable of impact resistance include plurality of battery cells and a plurality of kinetic energy absorbing elements. The arrangements further include a frame configured to encase the plurality of the kinetic energy absorbing elements and the battery cells. In some arrangements the frame and/or the kinetic energy absorbing elements can be made of topologically interlocked materials.

An analogue of Morse theory for planar linear networks and the generalized Steiner problem

International Nuclear Information System (INIS)

Karpunin, G A

2000-01-01

A study is made of the generalized Steiner problem: the problem of finding all the locally minimal networks spanning a given boundary set (terminal set). It is proposed to solve this problem by using an analogue of Morse theory developed here for planar linear networks. The space K of all planar linear networks spanning a given boundary set is constructed. The concept of a critical point and its index is defined for the length function l of a planar linear network. It is shown that locally minimal networks are local minima of l on K and are critical points of index 1. The theorem is proved that the sum of the indices of all the critical points is equal to χ(K)=1. This theorem is used to find estimates for the number of locally minimal networks spanning a given boundary set

Optimal Point-to-Point Trajectory Tracking of Redundant Manipulators using Generalized Pattern Search

Directory of Open Access Journals (Sweden)

Thi Rein Myo

2008-11-01

Full Text Available Optimal point-to-point trajectory planning for planar redundant manipulator is considered in this study. The main objective is to minimize the sum of the position error of the end-effector at each intermediate point along the trajectory so that the end-effector can track the prescribed trajectory accurately. An algorithm combining Genetic Algorithm and Pattern Search as a Generalized Pattern Search GPS is introduced to design the optimal trajectory. To verify the proposed algorithm, simulations for a 3-D-O-F planar manipulator with different end-effector trajectories have been carried out. A comparison between the Genetic Algorithm and the Generalized Pattern Search shows that The GPS gives excellent tracking performance.

All three-loop four-point correlators of half-BPS operators in planar N=4 SYM

Energy Technology Data Exchange (ETDEWEB)

Chicherin, Dmitry [Laboratoire d’Annecy-le-Vieux de Physique Théorique (LAPTH),UMR 5108, Université de Savoie, CNRS,B.P. 110, F-74941 Annecy-le-Vieux (France); Drummond, James [School of Physics & Astronomy, University of Southampton,Highfield, Southampton, SO17 1BJ (United Kingdom); Heslop, Paul [Mathematics Department, Durham University, Science Laboratories,South Rd, Durham DH1 3LE (United Kingdom); Sokatchev, Emery [Laboratoire d’Annecy-le-Vieux de Physique Théorique (LAPTH),UMR 5108, Université de Savoie, CNRS,B.P. 110, F-74941 Annecy-le-Vieux (France); Physics Department, Theory Unit, CERN,CH -1211, Geneva 23 (Switzerland)

2016-08-08

We obtain the planar correlation function of four half-BPS operators of arbitrary weights, up to three loops. Our method exploits only elementary properties of the integrand of the planar correlator, such as its symmetries and singularity structure. This allows us to write down a general ansatz for the integrand. The coefficients in the ansatz are fixed by means of a powerful light-cone OPE relation between correlators with different weights. Our result is formulated in terms of a limited number of functions built from known one-, two- and three-loop conformal integrals. These results are useful for checking recent integrability predictions for the OPE structure constants.

Analysis of sound absorption performance of an electroacoustic absorber using a vented enclosure

Science.gov (United States)

Cho, Youngeun; Wang, Semyung; Hyun, Jaeyub; Oh, Seungjae; Goo, Seongyeol

2018-03-01

The sound absorption performance of an electroacoustic absorber (EA) is primarily influenced by the dynamic characteristics of the loudspeaker that acts as the actuator of the EA system. Therefore, the sound absorption performance of the EA is maximum at the resonance frequency of the loudspeaker and tends to degrade in the low-frequency and high-frequency bands based on this resonance frequency. In this study, to adjust the sound absorption performance of the EA system in the low-frequency band of approximately 20-80 Hz, an EA system using a vented enclosure that has previously been used to enhance the radiating sound pressure of a loudspeaker in the low-frequency band, is proposed. To verify the usefulness of the proposed system, two acoustic environments are considered. In the first acoustic environment, the vent of the vented enclosure is connected to an external sound field that is distinct from the sound field coupled to the EA. In this case, the acoustic effect of the vented enclosure on the performance of the EA is analyzed through an analytical approach using dynamic equations and an impedance-based equivalent circuit. Then, it is verified through numerical and experimental approaches. Next, in the second acoustic environment, the vent is connected to the same external sound field as the EA. In this case, the effect of the vented enclosure on the EA is investigated through an analytical approach and finally verified through a numerical approach. As a result, it is confirmed that the characteristics of the sound absorption performances of the proposed EA system using the vented enclosure in the two acoustic environments considered in this study are different from each other in the low-frequency band of approximately 20-80 Hz. Furthermore, several case studies on the change tendency of the performance of the EA using the vented enclosure according to the critical design factors or vent number for the vented enclosure are also investigated. In the future

9 CFR 3.53 - Primary enclosures.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Primary enclosures. 3.53 Section 3.53 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ANIMAL... maintained in good repair to protect the rabbits from injury, to contain them, and to keep predators out. (2...

Standard Guide for Testing Materials for Aerospace Plastic Transparent Enclosures

CERN Document Server

American Society for Testing and Materials. Philadelphia

2008-01-01

1.1 This guide is intended to summarize the standard test methods available on individual and composite materials utilized in fabrication of aerospace plastic transparent enclosures. As such, it is intended to specifically include transparent thermoplastics, transparent elastomers, and reinforced plastics, whether thermoplastic or thermosetting. 1.2 This guide is intended as an aid in the search for test methods pertinent to Aerospace Plastic Transparent Enclosures. It should be understood that all methods listed may not apply to all enclosures. 1.3 The standards included refer to the properties or aspects listed in Table 1. The properties or aspects are listed in alphabetical order and the descriptions used are intended to facilitate the search. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limi...

Enclosure environment characterization testing for the base line validation of computer fire simulation codes

International Nuclear Information System (INIS)

Nowlen, S.P.

1987-03-01

This report describes a series of fire tests conducted under the direction of Sandia National Laboratories for the US Nuclear Regulatory Commission. The primary purpose of these tests was to provide data against which to validate computer fire environment simulation models to be used in the analysis of nuclear power plant enclosure fire situations. Examples of the data gathered during three of the tests are presented, though the primary objective of this report is to provide a timely description of the test effort itself. These tests were conducted in an enclosure measuring 60x40x20 feet constructed at the Factory Mutual Research Corporation fires test facility in Rhode Island. All of the tests utilized forced ventilation conditions. The ventilation system was designed to simulate typical nuclear power plant installation practices and ventilation rates. A total of 22 tests using simple gas burner, heptane pool, methanol pool, and PMMA solid fires was conducted. Four of these tests were conducted with a full-scale control room mockup in place. Parameters varied during testing were fire intensity, enclosure ventilation rate, and fire location. Data gathered include air temperatures, air velocities, radiative and convective heat flux levels, optical smoke densities, inner and outer enclosure surface temperatures, enclosure surface heat flux levels, and gas concentrations within the enclosure in the exhaust stream

Two characteristics of planar intertwined basins of attraction

International Nuclear Information System (INIS)

Ding Changming

2012-01-01

Highlights: ► A new mathematical definition of intertwined basins of attraction is proposed. ► Basins are intertwined iff a limit set of stable manifold contains at least two points. ► Basins are intertwined iff the closure of stable manifold is not arc-connected. ► The intertwining property is preserved by topologically equivalent dynamical systems. - Abstract: In this paper, we investigate the intertwined basins of attraction for planar dynamical systems. We prove that the intertwining property is preserved by topologically equivalent systems. Two necessary and sufficient conditions for a planar system having intertwined basins are given.

Simplifying massive planar subdivisions

DEFF Research Database (Denmark)

Arge, Lars; Truelsen, Jakob; Yang, Jungwoo

2014-01-01

We present the first I/O- and practically-efficient algorithm for simplifying a planar subdivision, such that no point is moved more than a given distance εxy and such that neighbor relations between faces (homotopy) are preserved. Under some practically realistic assumptions, our algorithm uses ....... For example, for the contour map simplification problem it is significantly faster than the previous algorithm, while obtaining approximately the same simplification factor. Read More: http://epubs.siam.org/doi/abs/10.1137/1.9781611973198.3...

Cold Climate Building Enclosure Solutions

Energy Technology Data Exchange (ETDEWEB)

Kosny, Jan [Fraunhofer CSE, Cambridge, MA (United States); Fallahi, Ali [Fraunhofer CSE, Cambridge, MA (United States); Shukla, Nitin [Fraunhofer CSE, Cambridge, MA (United States)

2013-01-01

This project investigates the energy performance and cost effectiveness of several state-of-the-art retrofit strategies that could be used in triple-deckers and colonial houses, common house types in New England. Several emerging building enclosure technologies were integrated, including high R-value aerogel and vacuum insulations, in forms that would be energy efficient, flexible for different retrofit scenarios, durable, and potentially cost-competitive for deep energy retrofits.

Semi-empirical prediction of moisture build-up in an electronic enclosure using analysis of variance (ANOVA)

DEFF Research Database (Denmark)

Shojaee Nasirabadi, Parizad; Conseil, Helene; Mohanty, Sankhya

2016-01-01

Electronic systems are exposed to harsh environmental conditions such as high humidity in many applications. Moisture transfer into electronic enclosures and condensation can cause several problems as material degradation and corrosion. Therefore, it is important to control the moisture content...... and the relative humidity inside electronic enclosures. In this work, moisture transfer into a typical polycarbonate electronic enclosure with a cylindrical shape opening is studied. The effects of four influential parameters namely, initial relative humidity inside the enclosure, radius and length of the opening...... and temperature are studied. A set of experiments are done based on a fractional factorial design in order to estimate the time constant for moisture transfer into the enclosure by fitting the experimental data to an analytical quasi-steady-state model. According to the statistical analysis, temperature...

Electric devices used in radioactive handling enclosures of the high activity laboratory

International Nuclear Information System (INIS)

Gaigeot, F.; Laurent, H.

1958-08-01

This report describes several electric, electronic and electromechanical assemblies which are used in radioactive handling enclosures. The authors propose an overview of existing or foreseen devices: a device to lift covers, a brightness comparator, a high voltage device to perform electrophoresis, a level sensor or regulator device, a regulation device to control under-pressure in an enclosure [fr

Natural convection in enclosures. Proceedings of the nineteenth national heat transfer conference, Orlando, FL, July 27-30, 1980

International Nuclear Information System (INIS)

Torrance, K.E.; Catton, I.

1980-01-01

Natural convection in low aspect ratio rectangular enclosures is considered along with three-dimensional convection within rectangular boxes, natural convection flow visualization in irradiated water cooled by air flow over the surface, free convection in vertical slots, the stratification in natural convection in vertical enclosures, the flow structure with natural convection in inclined air-filled enclosures, and natural convection across tilted, rectangular enclosures of small aspect ratio. Attention is given to the effect of wall conduction and radiation on natural convection in a vertical slot with uniform heat generation of the heated wall, a numerical study of thermal insulation enclosure, free convection in a piston-cylinder enclosure with sinusoidal piston motion, natural convection heat transfer between bodies and their spherical enclosure, an experimental study of the steady natural convection in a horizontal annulus with irregular boundaries, three-dimensional natural convection in a porous medium between concentric inclined cylinders, a numerical solution for natural convection in concentric spherical annuli, and heat transfer by natural convection in porous media between two concentric spheres

Noise pollution of air compressor and its noise reduction procedures by using an enclosure

Directory of Open Access Journals (Sweden)

Farhad Forouharmajd

2012-01-01

Conclusions: An overall noise reduction by 25 dB with the use of mineral wool as an extra liner on the inside of the enclosure, suggests that the effectiveness of the enclosure can be increased by using such absorber materials.

I/O-Efficient Planar Range Skyline and Attrition Priority Queues

DEFF Research Database (Denmark)

Kejlberg-Rasmussen, Casper; Tao, Yufei; Tsakalidis, Konstantinos

2013-01-01

We study the static and dynamic planar range skyline reporting problem in the external memory model with block size B, under a linear space budget. The problem asks for an O(n/B) space data structure that stores n points in the plane, and supports reporting the k maximal input points (a.k.a.skyli...

First Interlaboratory Comparison on Calibration of Temperature-Controlled Enclosures in Turkey

Science.gov (United States)

Uytun, A.; Kalemci, M.

2017-11-01

The number of accredited laboratories in the field of calibration of temperature-controlled enclosures has been increasing in Turkey. One of the main criteria demonstrating the competence of a calibration laboratory is successful participation in interlaboratory comparisons. Therefore, TUBITAK UME Temperature Laboratory organized the first interlaboratory comparison on "Calibration of Temperature-Controlled Enclosures" in Turkey as a pilot laboratory between January and November, 2013. Forty accredited laboratories which provide routine calibration services to the industry in this field participated in the comparison. The standards used during the comparison was a climatic chamber for the measurements at -40 {°}C, -20 {°}C, 40 {°}C and 100 {°}C and an oven for the measurements at 200 {°}C. The protocol of the comparison was prepared considering guide EURAMET cg-20 and BS EN/IEC standards 600068-3-5 and 600068-3-11. During the comparison measurements, each participant had the liberty to choose the most convenient calibration points in terms of their accreditation scope among the values mentioned above and carried out on-site measurements at UME. The details and the results of this comparison are given in the paper. Determination of the statistical consistency of the results with the uncertainties given by the participants can be assessed by the method of En value assessment for each laboratory. En values for all measurement results based on the results of pilot and participating laboratories were calculated.

A sealed enclosure of the glove box type

International Nuclear Information System (INIS)

Moreels, Pierre.

1974-01-01

The invention relates to a sealed enclosure of the glove-box type. According to the invention, the box-frame comprises: angle-bars having a right-angled cross-section, sealing joints, tightening bars and fastening means [fr

All three-loop four-point correlators of half-BPS operators in planar $ \\mathcal{N} $ = 4 SYM

CERN Document Server

Chicherin, Dmitry; Heslop, Paul; Sokatchev, Emery

2016-01-01

We obtain the planar correlation function of four half-BPS operators of arbitrary weights, up to three loops. Our method exploits only elementary properties of the integrand of the planar correlator, such as its symmetries and singularity structure. This allows us to write down a general ansatz for the integrand. The coefficients in the ansatz are fixed by means of a powerful light-cone OPE relation between correlators with different weights. Our result is formulated in terms of a limited number of functions built from known one-, two- and three-loop conformal integrals. These results are useful for checking recent integrability predictions for the OPE structure constants.

Dynamic Planar Range Maxima Queries

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Tsakalidis, Konstantinos

2011-01-01

We consider the dynamic two-dimensional maxima query problem. Let P be a set of n points in the plane. A point is maximal if it is not dominated by any other point in P. We describe two data structures that support the reporting of the t maximal points that dominate a given query point, and allow...... for insertions and deletions of points in P. In the pointer machine model we present a linear space data structure with O(logn + t) worst case query time and O(logn) worst case update time. This is the first dynamic data structure for the planar maxima dominance query problem that achieves these bounds...... are integers in the range U = {0, …,2 w  − 1 }. We present a linear space data structure that supports 3-sided range maxima queries in O(logn/loglogn+t) worst case time and updates in O(logn/loglogn) worst case time. These are the first sublogarithmic worst case bounds for all operations in the RAM model....

Enclosure for small animals during awake animal imaging

Science.gov (United States)

Goddard, Jr., James S

2013-11-26

An enclosure or burrow restrains an awake animal during an imaging procedure. A tubular body, made from a radiolucent material that does not attenuate x-rays or gamma rays, accepts an awake animal. A proximal end of the body includes an attachment surface that corresponds to an attachment surface of an optically transparent and optically uniform window. An anti-reflective coating may be applied to an inner surface, an outer surface, or both surfaces of the window. Since the window is a separate element of the enclosure and it is not integrally formed as part of the body, it can be made with optically uniform thickness properties for improved motion tracking of markers on the animal with a camera during the imaging procedure. The motion tracking information is then used to compensate for animal movement in the image.

The influence of enclosure design on diurnal activity and stereotypic behaviour in captive Malayan Sun bears (Helarctos malayanus).

Science.gov (United States)

Tan, H M; Ong, S M; Langat, G; Bahaman, A R; Sharma, R S K; Sumita, S

2013-04-01

The effect of enclosure design on diurnal activity and stereotypic behaviour was assessed in 17 adult Malayan Sun bears (Helarctos malayanus), kept either in barren indoor enclosures or relatively enriched outdoor enclosures. Locomotion was the most frequent activity observed in the indoor bears, followed by resting. In contrast, conspecifics housed outdoors spent most of the time resting. Eleven forms of stereotypic behaviours were recorded in the bears, with pacing being the most common. The frequency and repertoire of stereotypies were significantly higher in the indoor bears irrespective of enclosure size. Novel forms of locomotor (forward-reverse pacing) and oral (allo-sucking) stereotypies were recorded. Oral stereotypies were predominant in the bears housed indoors, while patrolling was confined to the outdoor bears. Enclosure complexity significantly influences activity budget and occurrence of stereotypic behaviours, highlighting the importance of appropriate enclosure design and enrichment for the welfare of captive bears. Copyright © 2012 Elsevier Ltd. All rights reserved.

Captive chimpanzee (Pan troglodytes) behavior as a function of space per animal and enclosure type.

Science.gov (United States)

Neal Webb, Sarah J; Hau, Jann; Schapiro, Steven J

2018-03-01

Space per animal, or animal density, and enclosure type are important elements of functionally appropriate captive environments (FACEs) for chimpanzees. The National Institutes of Health (NIH) recommends that captive chimpanzees be maintained in areas of >250 ft 2 /animal. Several studies have investigated chimpanzee behavior in relation to space per animal, but only two studies have examined these variables while attempting to hold environmental complexity constant. Both have found few, if any, significant differences in behavior associated with increased space per animal. The NIH does not provide recommendations pertaining to enclosure type. Although Primadomes™ and corrals are considered acceptable FACE housing, no studies have investigated chimpanzee behavior in relation to these two common types of enclosures. We examined the NIH space per animal recommendation, and the effects of enclosure type, while maintaining similar levels of environmental complexity. We used focal animal observations to record the behavior of 22 chimpanzees in three social groups following within-facility housing transfers. Chimpanzees that were moved from an area with space below the NIH recommendation to the same type of enclosure with space above the recommendation (dome to double dome) exhibited significantly more locomotion and behavioral diversity post-transfer. Chimpanzees that were moved from an area with space below the recommendation to a different type of enclosure with space above the recommendation (dome to corral) exhibited significant increases in foraging and behavioral diversity, and a decrease in rough scratching. Lastly, chimpanzees that were moved from an area above the recommendation to a different enclosure type with space equal to the recommendation (corral to double dome) exhibited an increase in behavioral diversity. These results add to the body of literature that addresses the concept of specific minimum space requirements per chimpanzee, and highlight the

A Monte Carlo tool for evaluating VMAT and DIMRT treatment deliveries including planar detectors

International Nuclear Information System (INIS)

Asuni, G; Van Beek, T A; Venkataraman, S; McCurdy, B M C; Popescu, I A

2013-01-01

The aim of this work is to describe and validate a new general research tool that performs Monte Carlo (MC) simulations for volumetric modulated arc therapy (VMAT) and dynamic intensity modulated radiation therapy (DIMRT), simultaneously tracking dose deposition in both the patient CT geometry and an arbitrary planar detector system. The tool is generalized to handle either entrance or exit detectors and provides the simulated dose for the individual control-points of the time-dependent VMAT and DIMRT deliveries. The MC simulation tool was developed with the EGSnrc radiation transport. For the individual control point simulation, we rotate the patient/phantom volume only (i.e. independent of the gantry and planar detector geometries) using the gantry angle in the treatment planning system (TPS) DICOM RP file such that each control point has its own unique phantom file. After MC simulation, we obtained the total dose to the phantom by summing dose contributions for all control points. Scored dose to the sensitive layer of the planar detector is available for each control point. To validate the tool, three clinical treatment plans were used including VMAT plans for a prostate case and a head-and-neck case, and a DIMRT plan for a head-and-neck case. An electronic portal imaging device operated in ‘movie’ mode was used with the VMAT plans delivered to cylindrical and anthropomorphic phantoms to validate the code using an exit detector. The DIMRT plan was delivered to a novel transmission detector, to validate the code using an entrance detector. The total MC 3D absolute doses in patient/phantom were compared with the TPS doses, while 2D MC doses were compared with planar detector doses for all individual control points, using the gamma evaluation test with 3%/3 mm criteria. The MC 3D absolute doses demonstrated excellent agreement with the TPS doses for all the tested plans, with about 95% of voxels having γ 90% of percentage pixels with γ <1. We found that over

Electromagnetic coupling between transmitters and electro-explosive devices located within an enclosure.

Energy Technology Data Exchange (ETDEWEB)

Warne, Larry Kevin; Jorgenson, Roy Eberhardt; Coats, Rebecca Sue

2010-04-01

This report documents calculations conducted to determine if 42 low-power transmitters located within a metallic enclosure can initiate electro-explosive devices (EED) located within the same enclosure. This analysis was performed for a generic EED no-fire power level of 250 mW. The calculations show that if the transmitters are incoherent, the power available is 32 mW - approximately one-eighth of the assumed level even with several worst-case assumptions in place.

Optimizing the design and impact behavior of a polymeric enclosure

International Nuclear Information System (INIS)

Singh, R.; Mattoo, A.; Saigal, A.

2006-01-01

This paper focuses on the application of finite element analysis to design an electronic enclosure with improved impact resistance properties. With the growing push towards miniaturization there is a constant decrease in the wall thickness of the enclosure applications. This necessitates use of ribs to enhance the impact resistance. This study aims at investigating optimal design of ribs for improving impact resistance. The 'DSGZ' phenomenological constitutive model, which uniformly describes the entire range of stress-strain constitutive relationship of polymers under any monotonic loading mode is used to predict the plastic failure energies. Several simulation runs were performed based on the design parameters using a 2 3 factorial design of experiments. The results from these simulations were used to analyze and study the various design parameters and its influence on the impact energy. It was found that when designing enclosures with ribs with an objective to maximize the impact failure energy, stress should be laid on optimizing the ratio of wall thickness to rib height within permissible limits while center-to-center spacing between the ribs and rib thickness do not have a significant effect

Optimizing the design and impact behavior of a polymeric enclosure

Energy Technology Data Exchange (ETDEWEB)

Singh, R. [Department of Mechanical Engineering, Tufts University, Medford, MA 02155 (United States); Mattoo, A. [Department of Mechanical Engineering, Tufts University, Medford, MA 02155 (United States); Saigal, A. [Department of Mechanical Engineering, Tufts University, Medford, MA 02155 (United States)]. E-mail: anil.saigal@tufts.edu

2006-07-01

This paper focuses on the application of finite element analysis to design an electronic enclosure with improved impact resistance properties. With the growing push towards miniaturization there is a constant decrease in the wall thickness of the enclosure applications. This necessitates use of ribs to enhance the impact resistance. This study aims at investigating optimal design of ribs for improving impact resistance. The 'DSGZ' phenomenological constitutive model, which uniformly describes the entire range of stress-strain constitutive relationship of polymers under any monotonic loading mode is used to predict the plastic failure energies. Several simulation runs were performed based on the design parameters using a 2{sup 3} factorial design of experiments. The results from these simulations were used to analyze and study the various design parameters and its influence on the impact energy. It was found that when designing enclosures with ribs with an objective to maximize the impact failure energy, stress should be laid on optimizing the ratio of wall thickness to rib height within permissible limits while center-to-center spacing between the ribs and rib thickness do not have a significant effect.

The Numerical Study on the Influence of Prandtl Number and Height of the Enclosure

International Nuclear Information System (INIS)

Moon, Je-Young; Chung, Bum-Jin

2016-01-01

This study investigated numerically the internal flow depending on Prandtl number of fluid and height of enclosure. The two-dimensional numerical simulations were performed for several heights of enclosure in the range between 0.01 m and 0.074 m. It corresponds to the aspect ratio (H/L) ranged from 0.07 to 0.5. Prandtl number was 0.2, 0.7 and 7. Rayleigh number based on the height of enclosure ranged between 8.49x10 3 and 1.20x10 8 . The numerical calculations were carried out using FLUENT 6.3. In order to confirm the influence of Prandtl number and height of side walls on the internal flow and heat transfer of the horizontal enclosure, the numerical study is carried out using the FLUENT 6.3. The numerical results for the condition of top cooling only agree well with Rayleigh-Benard natural convection. When the top and side walls were cooled, the internal flow of enclosure is more complex. The thickness of thermal and velocity boundary layer varies with Prandtl number. For Pr>1 the behavior of cells is unstable and irregular owing to the entrained plume, whereas the internal flow for Pr<1 is stable and regular. Also, the number of cells increases depending on decrease of height. As a result, the heat exchange increases

Measurements of density profile evolution during the stably-stratified filling of an open enclosure

International Nuclear Information System (INIS)

Tarawneh, Constantine M.; Homan, K.O.

2008-01-01

The stably-stratified filling of an open enclosure produces an interfacial gradient layer which is transported through the enclosure with the bulk flow. The evolution of this interfacial layer is strongly time-dependent and is driven by the nature of the interaction between the internal gravity waves and the inlet-driven interfacial shear. Measurements of density profile evolution have been completed for a rectangular enclosure with a single corner inlet and density variation produced by saline concentration. This system serves as a mass transfer analog to large-scale, thermally-stratified energy storage devices, preserving dynamic similitude in a laboratory-scale system. The experiments covered jet Reynolds numbers of 200-2200 and Froude numbers of 0.06-0.6 in an enclosure with a width 23 times the jet inlet height. The density profiles are seen to be strongly asymmetric and exhibit growth rates significantly different than due to simple one-dimensional molecular diffusion. In addition, shadowgraph and hydrogen bubble visualizations of the density and velocity fields in the gradient layer show the persistence of complex multi-dimensional flow structure even at relatively late stages of the filling process when the gradient layer has been transported well away from the enclosure inlet. The evolution of the vertical density profile has been compared quantitatively to a quasi one-dimensional model based upon empirical diffusivity coefficients

Factors affecting wild rabbit production in extensive breeding enclosures: how can we optimise efforts?

Directory of Open Access Journals (Sweden)

José Guerrero-Casado

2013-09-01

Full Text Available The declining rabbit population in the Iberian Peninsula has led hunters and authorities to rear rabbits in captivity systems for their subsequent release. One alternative method to intensive rabbitry systems is the use of extensive breeding enclosures, since they produce animals of greater quality for hunting and conservation purposes. However, some of the factors that affect rabbit production in breeding enclosures are still unknown. The present study used partial least squares regression (PLSR to analyse the effects of plot size, scrub cover, slope, initial rabbit abundance, the resources needed to dig warrens, predation and proximity to other enclosures on rabbit abundance. The results of our study show a positive effect of the number of other fenced plots within a radius of 3 km, a positive relationship with the availability of optimal resources for building warrens and a positive influence of intermediate values of scrub cover. According to our results, to maximise rabbit production in the enclosures it would be advisable to concentrate the restocking effort by ensuring that the restocking plots are close to each other, thus avoiding isolated enclosures. Furthermore, the selection of plots with an appropriate scrub cover and high availability of elements that favour the construction of warrens, such as large stones, sloping land or tall shrubs, may optimise results.

Application of tuned sound enclosures to transformers

International Nuclear Information System (INIS)

Allan, K.N.; Ellingson, E.F.

1992-09-01

The objective of this program was to reduce the noise emitted from power transformers by using a close-fitting, integrally-mounted noise shell. The noise shell consists of a series of panels mounted to a framework, that is, in turn, supported by the tank by means of mounting brackets and neoprene isolators. The development work was directed specifically toward application to existing transformers, i.e. retrofit.This project is a follow-on to work done under project RP-579-1. That project developed the theory and applied it experimentally to an existing transformer. The results were somewhat disappointing, however, with an 8 dBA reduction achieved where 15 dBA was expected. This document reports the work performed covering the period from March 1, 1977, to December 31, 1978. A complete noise shell enclosure was installed on a transformer for Consumers Power Company (Jackson, Michigan). Costs projected on the basis of this installation and several business assumptions indicate an installed cost of 19.8% of a new, standard noise transformer. This is higher than originally expected, but lower than alternative noise control methods. It also has some features that should make it an even more attractive alternative. Material loss factor (generally termed damping) of the enclosure material was found to be a critical parameter. Addition of a damping treatment to the experimental shell increased the performance to the 15 dBA target reduction. Damping was also found to be critical on the demonstration unit. The plastic panels installed (loss factor 0.05) resulted in a noise reduction of 8.5 dBA, increasing to 11.6 dBA when acoustical foam was added inside the enclosure. Three panels were replaced with damped steel panels and an overall 16.5 dBA reduction is anticipated based on vibration measurements

High-order computer-assisted estimates of topological entropy

Science.gov (United States)

Grote, Johannes

The concept of Taylor Models is introduced, which offers highly accurate C0-estimates for the enclosures of functional dependencies, combining high-order Taylor polynomial approximation of functions and rigorous estimates of the truncation error, performed using verified interval arithmetic. The focus of this work is on the application of Taylor Models in algorithms for strongly nonlinear dynamical systems. A method to obtain sharp rigorous enclosures of Poincare maps for certain types of flows and surfaces is developed and numerical examples are presented. Differential algebraic techniques allow the efficient and accurate computation of polynomial approximations for invariant curves of certain planar maps around hyperbolic fixed points. Subsequently we introduce a procedure to extend these polynomial curves to verified Taylor Model enclosures of local invariant manifolds with C0-errors of size 10-10--10 -14, and proceed to generate the global invariant manifold tangle up to comparable accuracy through iteration in Taylor Model arithmetic. Knowledge of the global manifold structure up to finite iterations of the local manifold pieces enables us to find all homoclinic and heteroclinic intersections in the generated manifold tangle. Combined with the mapping properties of the homoclinic points and their ordering we are able to construct a subshift of finite type as a topological factor of the original planar system to obtain rigorous lower bounds for its topological entropy. This construction is fully automatic and yields homoclinic tangles with several hundred homoclinic points. As an example rigorous lower bounds for the topological entropy of the Henon map are computed, which to the best knowledge of the authors yield the largest such estimates published so far.

Productivity of a coral reef using boundary layer and enclosure methods

Science.gov (United States)

McGillis, W.R.; Langdon, C.; Loose, B.; Yates, K.K.; Corredor, Jorge

2011-01-01

The metabolism of Cayo Enrique Reef, Puerto Rico, was studied using in situ methods during March 2009. Benthic O2 fluxes were used to calculate net community production using both the boundary layer gradient and enclosure techniques. The boundary layer O2 gradient and the drag coefficients were used to calculate productivity ranging from -12.3 to 13.7 mmol O2 m-2 h-1. Productivity measurements from the enclosure method ranged from -11.0 to 12.9 mmol O2 m-2 h-1. During the study, the mean hourly difference between the methods was 0.65 mmol O2 m-2 h-1 (r2 = 0.92), resulting in well-reconciled estimates of net community production between the boundary layer (-33.1 mmol m-2 d-1) and enclosure (-46.3 mmol m-2 d-1) techniques. The results of these independent approaches corroborate quantified rates of metabolism at Cayo Enrique Reef. Close agreement between methods demonstrates that boundary layer measurements can provide near real-time assessments of coral reef health.

Reconstruction of Sound Source Pressures in an Enclosure Using the Phased Beam Tracing Method

DEFF Research Database (Denmark)

Jeong, Cheol-Ho; Ih, Jeong-Guon

2009-01-01

. First, surfaces of an extended source are divided into reasonably small segments. From each source segment, one beam is projected into the field and all emitted beams are traced. Radiated beams from the source reach array sensors after traveling various paths including the wall reflections. Collecting...... all the pressure histories at the field points, source-observer relations can be constructed in a matrix-vector form for each frequency. By multiplying the measured field data with the pseudo-inverse of the calculated transfer function, one obtains the distribution of source pressure. An omni......-directional sphere and a cubic source in a rectangular enclosure were taken as examples in the simulation tests. A reconstruction error was investigated by Monte Carlo simulation in terms of field point locations. When the source information was reconstructed by the present method, it was shown that the sound power...

Effects of Dredging and Lanthanum-Modified Clay on Water Quality Variables in an Enclosure Study in a Hypertrophic Pond

Directory of Open Access Journals (Sweden)

Miquel Lürling Guido Waajen

2017-05-01

Full Text Available An enclosure experiment was conducted between July and September 2009 to compare the effectiveness of a phosphate fixative, the lanthanum-modified bentonite clay Phoslock® (LMB, dredging, and their combination in controlling eutrophication in a hypertrophic urban pond in Heesch, The Netherlands. In total, 25 water quality variables were monitored. Multivariate analysis revealed that the combination LMB-treated and dredged enclosures deviated most from the pond (reference and the controls, and showed the strongest eutrophication reduction. Overall, dredging significantly increased transparency, lowered turbidity, and improved the oxygen conditions in the enclosures compared to non-dredged ones. Nonetheless, one dredged enclosure deviated dramatically from the others, which might reflect methodological issues with dredging. The LMB treatment appeared to be less effective at mitigating eutrophication than dredging, and phosphate concentrations even increased during the experiment in the LMB-treated enclosures. Chemical equilibrium modeling suggested that humic substances could have formed complexes with lanthanum (La from the LMB, rendering it unavailable for intercepting P over the course of the enclosure experiment. Residual lanthanum concentrations in combination dredging and LMB treatments exceeded the Dutch standard 10-fold. Total zooplankton abundance, and particularly Cladocera, increased in all enclosures over the course of the experiment. The limited effect of LMB in the enclosure experiment and the violation of the Dutch La standard when combined with dredging disqualify LMB as an intervention agent in the restoration of the pond.

Estimation of time-varying pollutant emission rates in a ventilated enclosure: inversion of a reduced model obtained by experimental application of the modal identification method

International Nuclear Information System (INIS)

Girault, M; Maillet, D; Bonthoux, F; Galland, B; Martin, P; Braconnier, R; Fontaine, J R

2008-01-01

A method is proposed for the estimation of time-varying emission rates of pollutant sources in a ventilated enclosure, through the resolution of an inverse forced convection problem. Unsteady transport–diffusion of the pollutant is considered, with the assumption of a stationary velocity field remaining unchanged during emission (passive contaminant). The pollutant transport equation is therefore linear with respect to concentration. The source's location is also supposed to be known. As the first step, a reduced model (RM) linking concentrations at a set of control points to emission rates of sources is identified from experimental data by using the modal identification method (MIM). This parameter estimation problem uses transient contaminant concentration measurements made at control points inside the ventilated enclosure, corresponding to increasing and decreasing steps of emission rates. Such experimental modelling allows us to avoid dealing with a CFD code involving turbulence modelling and to get rid of uncertainties about sensors position. In a second step, the identified RM is used to solve an inverse forced convection problem: from contaminant concentration measured at the same control points, rates of sources emitting simultaneously are estimated with a sequential in time algorithm using future time steps

The Planar Sandwich and Other 1D Planar Heat Flow Test Problems in ExactPack

Energy Technology Data Exchange (ETDEWEB)

Singleton, Jr., Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-01-24

This report documents the implementation of several related 1D heat flow problems in the verification package ExactPack [1]. In particular, the planar sandwich class defined in Ref. [2], as well as the classes PlanarSandwichHot, PlanarSandwichHalf, and other generalizations of the planar sandwich problem, are defined and documented here. A rather general treatment of 1D heat flow is presented, whose main results have been implemented in the class Rod1D. All planar sandwich classes are derived from the parent class Rod1D.

Proposal of limit moment equation applicable to planar/non-planar flaw in wall thinned pipes under bending

International Nuclear Information System (INIS)

Tsuji, Masataka; Meshii, Toshiyuki

2011-01-01

Highlights: → A limit moment equation applicable to planar/non-planar flaw of 0 ≤ θ ≤ π found in wall thinned straight pipes was proposed. → An idea to rationally classify planar/non-planar flaw in wall thinned pipes was proposed. → The equation based on the experimental observation focused on the fracture mode. - Abstract: In this paper, a limit bending moment equation applicable to all types of planar and non-planar flaws in wall-thinned straight pipes under bending was proposed. A system to rationally classify the planar/non-planar flaws in wall-thinned pipes was suggested based on experimental observations focused on the fracture mode. The results demonstrate the importance of distinguishing between axial and circumferential long flaws in wall-thinned pipes.

Limiting enclosures. Method of control of the leak rate per hour. Enclosures of classes 1 and 2. Method of measurement of the increase of the oxygen titre in volume

International Nuclear Information System (INIS)

1984-07-01

The present standard can be applied to limiting enclosures working under depression or overpressure. It can be applied to limiting enclosures used for works on radioactive or toxic materials. The leak rate per hour is -2 h -1 . The measuring method uses oxygen determination after the enclusore is filled with an inert gas. The influence of pressure and temperature are analysed. The measurement installation and its operating way are presented; the accuracy of the method given. This standard supersedes the experimental standard of December 1982 [fr

Natural convection in wavy enclosures with volumetric heat sources

International Nuclear Information System (INIS)

Oztop, H.F.; Varol, Y.; Abu-Nada, E.; Chamkha, A.

2011-01-01

In this paper, the effects of volumetric heat sources on natural convection heat transfer and flow structures in a wavy-walled enclosure are studied numerically. The governing differential equations are solved by an accurate finite-volume method. The vertical walls of enclosure are assumed to be heated differentially whereas the two wavy walls (top and bottom) are kept adiabatic. The effective governing parameters for this problem are the internal and external Rayleigh numbers and the amplitude of wavy walls. It is found that both the function of wavy wall and the ratio of internal Rayleigh number (Ra I ) to external Rayleigh number (Ra E ) affect the heat transfer and fluid flow significantly. The heat transfer is predicted to be a decreasing function of waviness of the top and bottom walls in case of (IRa/ERa)>1 and (IRa/ERa)<1. (authors)

Direct simulation of natural convection in square porous enclosure

International Nuclear Information System (INIS)

Pourshaghaghy, A.; Hakkaki-Fard, A.; Mahdavi-Nejad, A.

2007-01-01

In this article, natural convection in a square porous enclosure is simulated by a direct numerical method. The solution method is based on a random distribution of solid blocks, which resembles the porous media within the cavity. The Navier-Stokes equations are solved directly in the fluid region without the assumption of volume averaging. The no-slip condition is applied on the surface of any solid particle, and the energy transport equation is solved separately for the solid phase and fluid flow. The local and average Nusselt numbers are presented for steady state for two different cases of thermal boundary conditions of the cavity walls. An oscillatory solution is observed for the local Nu number on the surface of the enclosure, and the critical Ra numbers are found in which natural convection flow is started within the cavity

Acoustic Pressure Waves in Vibrating 3-D Laminated Beam-Plate Enclosures

Directory of Open Access Journals (Sweden)

Charles A. Osheku

2009-01-01

Full Text Available The effect of structural vibration on the propagation of acoustic pressure waves through a cantilevered 3-D laminated beam-plate enclosure is investigated analytically. For this problem, a set of well-posed partial differential equations governing the vibroacoustic wave interaction phenomenon are formulated and matched for the various vibrating boundary surfaces. By employing integral transforms, a closed form analytical expression is computed suitable for vibroacoustic modeling, design analysis, and general aerospace defensive applications. The closed-form expression takes the form of a kernel of polynomials for acoustic pressure waves showing the influence of linear interface pressure variation across the axes of vibrating boundary surfaces. Simulated results demonstrate how the mode shapes and the associated natural frequencies can be easily computed. It is shown in this paper that acoustic pressure waves propagation are dynamically stable through laminated enclosures with progressive decrement in interfacial pressure distribution under the influence of high excitation frequencies irrespective of whether the induced flow is subsonic, sonic , supersonic, or hypersonic. Hence, in practice, dynamic stability of hypersonic aircrafts or jet airplanes can be further enhanced by replacing their noise transmission systems with laminated enclosures.

Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures

CERN Document Server

Greve, Albert

2010-01-01

Radio telescopes as well as communication antennas operate under the influence of gravity, temperature and wind. Among those, temperature influences may degrade the performance of a radio telescope through transient changes of the focus, pointing, path length and sensitivity, often in an unpredictable way. Thermal Design and Thermal Behaviour of Radio Telescopes and their Enclosures reviews the design and construction principles of radio telescopes in view of thermal aspects and heat transfer with the variable thermal environment; it explains supporting thermal model calculations and the application and efficiency of thermal protection and temperature control; it presents many measurements illustrating the thermal behaviour of telescopes in the environment of their observatory sites. The book benefits scientists and radio/communication engineers, telescope designers and construction firms as well as telescope operators, observatory staff, but also the observing astronomer who is directly confronted with the t...

Modeling of humidity-related reliability in enclosures with electronics

DEFF Research Database (Denmark)

Hygum, Morten Arnfeldt; Popok, Vladimir

2015-01-01

Reliability of electronics that operate outdoor is strongly affected by environmental factors such as temperature and humidity. Fluctuations of these parameters can lead to water condensation inside enclosures. Therefore, modelling of humidity distribution in a container with air and freely exposed...

Thermal Transmission through Existing Building Enclosures: Destructive Monitoring in Intermediate Layers versus Non-Destructive Monitoring with Sensors on Surfaces.

Science.gov (United States)

Echarri, Víctor; Espinosa, Almudena; Rizo, Carlos

2017-12-08

Opaque enclosures of buildings play an essential role in the level of comfort experienced indoors and annual energy demand. The impact of solar radiation and thermal inertia of the materials that make up the multi-layer enclosures substantially modify thermal transmittance behaviour of the enclosures. This dynamic form of heat transfer, additionally affected by indoor HVAC systems, has a substantial effect on the parameters that define comfort. It also has an impact on energy demand within a daily cycle as well as throughout a one-year use cycle. This study describes the destructive monitoring of an existing block of flats located in Alicante. Once the enclosure was opened, sensors of temperature (PT100), air velocity, and relative humidity were located in the different layers of the enclosure, as well as in the interior and exterior surfaces. A pyranometer was also installed to measure solar radiation levels. A temperature data correction algorithm was drawn up to address irregularities produced in the enclosure. The algorithm was applied using a Raspberry Pi processor in the data collection system. The comparative results of temperature gradients versus non-destructive monitoring systems are presented, providing measures of the transmittance value, surface temperatures and indoor and outdoor air temperatures. This remote sensing system can be used in future studies to quantify and compare the energy savings of different enclosure construction solutions.

Thermal Transmission through Existing Building Enclosures: Destructive Monitoring in Intermediate Layers versus Non-Destructive Monitoring with Sensors on Surfaces

Directory of Open Access Journals (Sweden)

Víctor Echarri

2017-12-01

Full Text Available Opaque enclosures of buildings play an essential role in the level of comfort experienced indoors and annual energy demand. The impact of solar radiation and thermal inertia of the materials that make up the multi-layer enclosures substantially modify thermal transmittance behaviour of the enclosures. This dynamic form of heat transfer, additionally affected by indoor HVAC systems, has a substantial effect on the parameters that define comfort. It also has an impact on energy demand within a daily cycle as well as throughout a one-year use cycle. This study describes the destructive monitoring of an existing block of flats located in Alicante. Once the enclosure was opened, sensors of temperature (PT100, air velocity, and relative humidity were located in the different layers of the enclosure, as well as in the interior and exterior surfaces. A pyranometer was also installed to measure solar radiation levels. A temperature data correction algorithm was drawn up to address irregularities produced in the enclosure. The algorithm was applied using a Raspberry Pi processor in the data collection system. The comparative results of temperature gradients versus non-destructive monitoring systems are presented, providing measures of the transmittance value, surface temperatures and indoor and outdoor air temperatures. This remote sensing system can be used in future studies to quantify and compare the energy savings of different enclosure construction solutions.

Thermal Transmission through Existing Building Enclosures: Destructive Monitoring in Intermediate Layers versus Non-Destructive Monitoring with Sensors on Surfaces

Science.gov (United States)

Echarri, Víctor; Espinosa, Almudena; Rizo, Carlos

2017-01-01

Opaque enclosures of buildings play an essential role in the level of comfort experienced indoors and annual energy demand. The impact of solar radiation and thermal inertia of the materials that make up the multi-layer enclosures substantially modify thermal transmittance behaviour of the enclosures. This dynamic form of heat transfer, additionally affected by indoor HVAC systems, has a substantial effect on the parameters that define comfort. It also has an impact on energy demand within a daily cycle as well as throughout a one-year use cycle. This study describes the destructive monitoring of an existing block of flats located in Alicante. Once the enclosure was opened, sensors of temperature (PT100), air velocity, and relative humidity were located in the different layers of the enclosure, as well as in the interior and exterior surfaces. A pyranometer was also installed to measure solar radiation levels. A temperature data correction algorithm was drawn up to address irregularities produced in the enclosure. The algorithm was applied using a Raspberry Pi processor in the data collection system. The comparative results of temperature gradients versus non-destructive monitoring systems are presented, providing measures of the transmittance value, surface temperatures and indoor and outdoor air temperatures. This remote sensing system can be used in future studies to quantify and compare the energy savings of different enclosure construction solutions. PMID:29292781

Variability in DMSA reporting following urinary tract infection in children: pinhole, planar, and pinhole with planar

International Nuclear Information System (INIS)

Rossleigh, M.A.; Christian, C.L.; Craig, J.C.; Howman-Giles, R.B.; Grunewald, S.

2004-01-01

Purpose: To determine whether the provision of DMSA images obtained by pinhole collimation reduces inter-observer variability of reporting compared with planar DMSA images alone. Methods: One hundred consecutive DMSA images were independently interpreted three times (pinhole alone, planar alone, pinhole and planar) by four participating nuclear medicine specialists from different departments and in random order. The presence or absence of renal parenchymal abnormality was classified using the modified four level grading system of Goldraich with mean values for the 6 comparisons reported. Results: The proportion of DMSA images interpreted as abnormal was 31% for planar, 34% for pinhole and 33% for planar with pinhole. Agreement was 89% for planar alone, 89% for pinhole alone and 90% for planar with pinhole, with kappa values 0.74, 0.75 and 0.80 respectively for the normal-abnormal scan classification of individual children. These results did not vary appreciably whether interpretation of patients, kidneys or kidney zones was compared. Reasons for disagreement in reporting included different interpretations of 'abnormalities' as normal anatomical variations (splenic impression, fetal lobulation, duplex collecting systems, column of Bertin) or true parenchymal abnormalities, different adjustments in thresholds for reporting abnormality when images were technically suboptimal, different weighting given to pinhole and planar images when both were provided, and error. Conclusion: Four experienced nuclear medicine physicians showed substantial agreement in the interpretation of planar alone, pinhole alone and planar with pinhole DMSA images, but the provision of both sets of images, planar and pinhole, did not reduce variability. (authors)

Ventilation of radioactive enclosures

International Nuclear Information System (INIS)

Caminade, F.; Laurent, H.

1957-01-01

Mechanical, physical and chemical manipulations on radioactive products must be carried out in properly ventilated enclosed places. The air extracted can only be discharged into the atmosphere after a correct filtration. The power of the ventilation systems is a function of the dimensions and purpose of the enclosure? The choice of types of filter is determined by the physical state and chemical nature of the radioactive materials to be manipulated. This study deals with the individual equipment of small installations: glove boxes, manipulation boxes with outside control and, if necessary, production chambers (maximum useful volume: 5 m 3 ). The performances of three types of 'ventilators', and the modifications provided by the addition of filters, are measured and compared. (author) [fr

Humidity Build-Up in a Typical Electronic Enclosure Exposed to Cycling Conditions and Effect on Corrosion Reliability

DEFF Research Database (Denmark)

Conseil, Helene; Gudla, Visweswara Chakravarthy; Jellesen, Morten Stendahl

2016-01-01

The design of electronic device enclosures plays a major role in determining the humidity build-up inside the device as a response to the varying external humidity. Therefore, the corrosion reliability of electronic devices has direct connection to the enclosure design. This paper describes......, thermal mass, and port/opening size. The effect of the internal humidity build-up on corrosion reliability has been evaluated by measuring the leakage current (LC) on interdigitated test comb patterns, which are precontaminated with sodium chloride and placed inside the enclosure. The results showed...... that the exposure to cycling temperature causes significant change of internal water vapor concentration. The maximum value of humidity reached was a function of the opening size and the presence of thermal mass inside the enclosure. A pumping effect was observed due to cycling temperature, and the increase...

Enhancing monochromatic multipole emission by a subwavelength enclosure of degenerate Mie resonances

KAUST Repository

Zhao, Jiajun

2017-07-06

Sound emission is inefficient at low frequencies as limited by source size. This letter presents enhancing emission of monochromatic monopole and multipole sources by enclosing the source with a subwavelength circular enclosure filled of an anisotropic material of a low radial sound speed. The anisotropy is associated with an infinite tangential density along the azimuth. Numerical simulations show that emission gain is produced at frequencies surrounding degenerate Mie resonant frequencies of the enclosure, and meanwhile the radiation directivity pattern is well preserved. The degeneracy is theoretically analyzed. A realization of the material is suggested by using a space-coiling structure.

Analysis of moisture transport between connected enclosures under a forced thermal gradient

DEFF Research Database (Denmark)

Staliulionis, Zygimantas; Joshy, Salil; Ambat, Rajan

2016-01-01

and humidity control solutions. While high fidelity CFD codes are too time consuming due to computational effort/time, the well-known Resistor-Capacitor (RC) approach has much lower calculation time and is more efficient to use in enclosures without too complex geometry in their interior. Thus, the objective...... of this paper is to build an in-house code based on the RC approach for simulating coupled heat and mass transport. The developed code is used for simulating moisture transport between two boxes/enclosures having different temperatures, connected with a tube of known geometry. It has also the capability...

How to draw a planarization

NARCIS (Netherlands)

Bläsius, T.; Radermacher, M.; Rutter, I.; Steffen, B.; Baier, C.; van den Brand, M.; Eder, J.; Hinchey, M.; Margaria, T.

2017-01-01

We study the problem of computing straight-line drawings of non-planar graphs with few crossings. We assume that a crossing-minimization algorithm is applied first, yielding a planarization, i.e., a planar graph with a dummy vertex for each crossing, that fixes the topology of the resulting drawing.

Analysis of Shift and Deformation of Planar Surfaces Using the Least Squares Plane

Directory of Open Access Journals (Sweden)

Hrvoje Matijević

2006-12-01

Full Text Available Modern methods of measurement developed on the basis of advanced reflectorless distance measurement have paved the way for easier detection and analysis of shift and deformation. A large quantity of collected data points will often require a mathematical model of the surface that fits best into these. Although this can be a complex task, in the case of planar surfaces it is easily done, enabling further processing and analysis of measurement results. The paper describes the fitting of a plane to a set of collected points using the least squares distance, with previously excluded outliers via the RANSAC algorithm. Based on that, a method for analysis of the deformation and shift of planar surfaces is also described.

A Planar Quasi-Static Constraint Mode Tire Model

Science.gov (United States)

2015-07-10

strikes a balance between simple tire models that lack the fidelity to make accurate chassis load predictions and computationally intensive models that...strikes a balance between heuristic tire models (such as a linear point-follower) that lack the fidelity to make accurate chassis load predictions...UNCLASSIFIED: Distribution Statement A. Cleared for public release A PLANAR QUASI-STATIC CONSTRAINT MODE TIRE MODEL Rui Maa John B. Ferris

Mathematical modelling of moisture transport into an electronic enclosure under non-isothermal conditions

DEFF Research Database (Denmark)

Staliulionis, Ž.; Mohanty, S.; Jabbari, Mahmoud

2017-01-01

In contrast to high fidelity CFD codes which require higher computational effort/time, the well-known Resistor-Capacitor (RC) approach requires much lower calculation time, but has a lower resolution of the geometrical arrangement. Therefore, for enclosures without too complex geometry in their i......In contrast to high fidelity CFD codes which require higher computational effort/time, the well-known Resistor-Capacitor (RC) approach requires much lower calculation time, but has a lower resolution of the geometrical arrangement. Therefore, for enclosures without too complex geometry...

Two-Loop Master Integrals for $\\gamma^{*} \\to 3$ Jets the Non-Planar Topologies

CERN Document Server

Gehrmann, T

2001-01-01

The calculation of the two-loop corrections to the three-jet production rate and to event shapes in electron--positron annihilation requires the computation of a number of two-loop four-point master integrals with one off-shell and three on-shell legs. Up to now, only those master integrals corresponding to planar topologies were known. In this paper, we compute the yet outstanding non-planar master integrals by solving differential equations in the external invariants which are fulfilled by these master integrals. We obtain the master integrals as expansions in $\\e=(4-d)/2$, where $d$ is the space-time dimension. The fully analytic results are expressed in terms of the two-dimensional harmonic polylogarithms already introduced in the evaluation of the planar topologies.

Design of special planar linkages

CERN Document Server

Zhao, Jing-Shan; Ma, Ning; Chu, Fulei

2013-01-01

Planar linkages play a very important role in mechanical engineering. As the simplest closed chain mechanisms, planar four-bar linkages are widely used in mechanical engineering, civil engineering and aerospace engineering.Design of Special Planar Linkages proposes a uniform design theory for planar four-bar linkages. The merit of the method proposed in this book is that it allows engineers to directly obtain accurate results when there are such solutions for the specified n precise positions; otherwise, the best approximate solutions will be found. This book discusses the kinematics and reach

Free convective condensation in a vertical enclosure

Energy Technology Data Exchange (ETDEWEB)

Fox, R.J.; Peterson, P.F. [Univ. of California, Berkeley, CA (United States); Corradini, M.L.; Pernsteiner, A.P. [Univ. of Wisconsin, Madison, WI (United States)

1995-09-01

Free convective condensation in a vertical enclosure was studied numerically and the results were compared with experiments. In both the numerical and experimental investigations, mist formation was observed to occur near the cooling wall, with significant droplet concentrations in the bulk. Large recirculation cells near the end of the condensing section were generated as the heavy noncondensing gas collecting near the cooling wall was accelerated downward. Near the top of the enclosure the recirculation cells became weaker and smaller than those below, ultimately disappearing near the top of the condenser. In the experiment the mist density was seen to be highest near the wall and at the bottom of the condensing section, whereas the numerical model predicted a much more uniform distribution. The model used to describe the formation of mist was based on a Modified Critical Saturation Model (MCSM), which allows mist to be generated once the vapor pressure exceeds a critical value. Equilibrium, nonequilibrium, and MCSM calculations were preformed, showing the experimental results to lie somewhere in between the equilibrium and nonequilibrium predictions of the numerical model. A single adjustable constant (indicating the degree to which equilibrium is achieved) is used in the model in order to match the experimental results.

Transient characteristics of thermal energy storage in an enclosure packed with MEPCM particles

International Nuclear Information System (INIS)

Siao, Yong-Hao; Yan, Wei-Mon; Lai, Chi-Ming

2015-01-01

The heat transfer characteristics of phase change materials have been of continuing interest of research due to various potential technical applications, such as the latent-heat thermal energy storage, thermal protection, as well as active/passive electronic cooling. In this work, the transient characteristics of thermal energy storage in a partitioned enclosure filled with microencapsulated phase change material (MEPCM) particles were investigated experimentally and numerically. To examine the different melting temperature effects, two different MEPCM particles are tested. The core phase change materials of the MEPCM are n-octadecane with melting temperature about T M  = 28 °C and 37 °C. The enclosure is partitioned and is differentially heated by the two horizontal isothermal surfaces, while the other vertical surfaces are considered thermally insulated. The studies have been undertaken for five sets of the hot and cold wall temperatures imposed across the enclosure. The consequents show that the numerical results are in agreement with the measured data. At the initial transient, the net energy storage in enclosure, Q net , increases with the time Fo. Finally, the Q net approaches quickly the steady state for the case with a higher temperature difference of T h  − T c . Additionally, higher dimensionless accumulated energy through the hot wall Q h and cold wall Q c is found for a case with higher hot wall temperature T h

Numerical analysis of a heat-generating, truncated conical porous bed in a fluid-filled enclosure

International Nuclear Information System (INIS)

Chakravarty, Aranyak; Datta, Priyankan; Ghosh, Koushik; Sen, Swarnendu; Mukhopadhyay, Achintya

2016-01-01

Analysis of natural convection in enclosures containing heat generating porous medium has important applications related to geothermal, chemical, thermal and nuclear energy such as in-vessel cooling of debris beds in nuclear reactors, cooling of coal stockpiles etc. The objective of the present numerical study is to characterise the pattern of fluid flow and energy transfer during steady laminar natural convective flow in a cylindrical enclosure with a centrally placed heat generating porous bed. Flow through porous region is modelled using Darcy–Brinkmann–Forchheimer model and local thermal equilibrium is assumed for the porous region. Analysis is carried out for a wide range of Rayleigh number (Ra), Darcy number (Da) and thermal conductivity ratio, as well as for different bed geometries. It is observed that in addition to Ra and Da, the bed geometry also plays a very important role in determining flow field and temperature distribution within the enclosure. Interestingly, a significant change is observed in energy transfer mode from the porous bed corresponding to specific values of bed permeability and bed heat generation rate. This is characterised in terms of Ra and Da. Further, it is observed that this change in energy transfer mode is highly dependent on Ra. - Highlights: • Natural convection is analysed in an enclosure with a heat generating porous bed. • Effect of dimensionless parameters as well as bed geometry has been investigated. • Energy transfer mechanism from porous bed changes with dimensionless parameters. • Bed geometry significantly affects fluid flow and energy transfer in the enclosure.

Potential arsenic exposures in 25 species of zoo animals living in CCA-wood enclosures

International Nuclear Information System (INIS)

Gress, J.; Silva, E.B. da; Oliveira, L.M. de; Zhao, Di; Anderson, G.; Heard, D.; Stuchal, L.D.; Ma, L.Q.

2016-01-01

Animal enclosures are often constructed from wood treated with the pesticide chromated copper arsenate (CCA), which leaches arsenic (As) into adjacent soil during normal weathering. This study evaluated potential pathways of As exposure in 25 species of zoo animals living in CCA-wood enclosures. We analyzed As speciation in complete animal foods, dislodgeable As from CCA-wood, and As levels in enclosure soils, as well as As levels in biomarkers of 9 species of crocodilians (eggs), 4 species of birds (feathers), 1 primate species (hair), and 1 porcupine species (quills). Elevated soil As in samples from 17 enclosures was observed at 1.0–110 mg/kg, and enclosures housing threatened and endangered species had As levels higher than USEPA's risk-based Eco-SSL for birds and mammals of 43 and 46 mg/kg. Wipe samples of CCA-wood on which primates sit had dislodgeable As residues of 4.6–111 μg/100 cm 2 , typical of unsealed CCA-wood. Inorganic As doses from animal foods were estimated at 0.22–7.8 μg/kg bw/d. Some As levels in bird feathers and crocodilian eggs were higher than prior studies on wild species. However, hair from marmosets had 6.37 mg/kg As, 30-fold greater than the reference value, possibly due to their inability to methylate inorganic As. Our data suggested that elevated As in soils and dislodgeable As from CCA-wood could be important sources of As exposure for zoo animals. - Highlights: • Daily inorganic As dose from zoo animal foods was 0.22–7.8 μg/kg bw/day. • Total As concentrations in soils of zoo animal enclosures were 1.0–110 mg/kg. • Endangered zoo animals live in soils with As above USEPA Eco-SSLs for avian and mammal species. • Dislodgeable As on CCA-wood beams where primates sit was 4.6–111 μg/100 cm 2 . • Marmoset hair had 6.37 mg/kg As compared to a reference value of 0.21 mg/kg.

Potential arsenic exposures in 25 species of zoo animals living in CCA-wood enclosures

Energy Technology Data Exchange (ETDEWEB)

Gress, J. [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 201146 (China); Soil and Water Science Department, University of Florida, Gainesville, FL 32611 (United States); Silva, E.B. da; Oliveira, L.M. de [Soil and Water Science Department, University of Florida, Gainesville, FL 32611 (United States); Zhao, Di [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 201146 (China); Anderson, G. [Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Heard, D. [Department of Small Animal Clinical Sciences, University of Florida, Gainesville, FL 32610 (United States); Stuchal, L.D. [Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611 (United States); Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, FL 32611 (United States); Ma, L.Q., E-mail: lqma@ufl.edu [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 201146 (China); Soil and Water Science Department, University of Florida, Gainesville, FL 32611 (United States)

2016-05-01

Animal enclosures are often constructed from wood treated with the pesticide chromated copper arsenate (CCA), which leaches arsenic (As) into adjacent soil during normal weathering. This study evaluated potential pathways of As exposure in 25 species of zoo animals living in CCA-wood enclosures. We analyzed As speciation in complete animal foods, dislodgeable As from CCA-wood, and As levels in enclosure soils, as well as As levels in biomarkers of 9 species of crocodilians (eggs), 4 species of birds (feathers), 1 primate species (hair), and 1 porcupine species (quills). Elevated soil As in samples from 17 enclosures was observed at 1.0–110 mg/kg, and enclosures housing threatened and endangered species had As levels higher than USEPA's risk-based Eco-SSL for birds and mammals of 43 and 46 mg/kg. Wipe samples of CCA-wood on which primates sit had dislodgeable As residues of 4.6–111 μg/100 cm{sup 2}, typical of unsealed CCA-wood. Inorganic As doses from animal foods were estimated at 0.22–7.8 μg/kg bw/d. Some As levels in bird feathers and crocodilian eggs were higher than prior studies on wild species. However, hair from marmosets had 6.37 mg/kg As, 30-fold greater than the reference value, possibly due to their inability to methylate inorganic As. Our data suggested that elevated As in soils and dislodgeable As from CCA-wood could be important sources of As exposure for zoo animals. - Highlights: • Daily inorganic As dose from zoo animal foods was 0.22–7.8 μg/kg bw/day. • Total As concentrations in soils of zoo animal enclosures were 1.0–110 mg/kg. • Endangered zoo animals live in soils with As above USEPA Eco-SSLs for avian and mammal species. • Dislodgeable As on CCA-wood beams where primates sit was 4.6–111 μg/100 cm{sup 2}. • Marmoset hair had 6.37 mg/kg As compared to a reference value of 0.21 mg/kg.

Automated Coarse Registration of Point Clouds in 3d Urban Scenes Using Voxel Based Plane Constraint

Science.gov (United States)

Xu, Y.; Boerner, R.; Yao, W.; Hoegner, L.; Stilla, U.

2017-09-01

For obtaining a full coverage of 3D scans in a large-scale urban area, the registration between point clouds acquired via terrestrial laser scanning (TLS) is normally mandatory. However, due to the complex urban environment, the automatic registration of different scans is still a challenging problem. In this work, we propose an automatic marker free method for fast and coarse registration between point clouds using the geometric constrains of planar patches under a voxel structure. Our proposed method consists of four major steps: the voxelization of the point cloud, the approximation of planar patches, the matching of corresponding patches, and the estimation of transformation parameters. In the voxelization step, the point cloud of each scan is organized with a 3D voxel structure, by which the entire point cloud is partitioned into small individual patches. In the following step, we represent points of each voxel with the approximated plane function, and select those patches resembling planar surfaces. Afterwards, for matching the corresponding patches, a RANSAC-based strategy is applied. Among all the planar patches of a scan, we randomly select a planar patches set of three planar surfaces, in order to build a coordinate frame via their normal vectors and their intersection points. The transformation parameters between scans are calculated from these two coordinate frames. The planar patches set with its transformation parameters owning the largest number of coplanar patches are identified as the optimal candidate set for estimating the correct transformation parameters. The experimental results using TLS datasets of different scenes reveal that our proposed method can be both effective and efficient for the coarse registration task. Especially, for the fast orientation between scans, our proposed method can achieve a registration error of less than around 2 degrees using the testing datasets, and much more efficient than the classical baseline methods.

Echo signal from rough planar interfaces influence of roughness, angle, range and transducer type

DEFF Research Database (Denmark)

Wilhjelm, Jens E.; Pedersen, P.C.; Jacobsen, S.M.

1998-01-01

The received electrical signal from a pulse-echo system insonifying a planar acoustical interface was measured for varying degrees of rms roughness (0-0.16 mm), angle of incidence (typically +/-7°) and range to the transducer. A planar and a focused 5 MHz transducer was used. When insonifying...... a smooth interface, the normalized spectrum of the received signals for a planar transducer exhibits an increasing number of nulls with increased angle of insonification, as predicted from numerical modeling while the dependence on insonification angle for the focused transducer was smaller and the null...... pattern was much less distinct. For the planar transducer and for the focused transducer with the interface located at the geometrical point of focus, the energy of the received signal as a function of incident angle was approximately Gaussian with maximum at 0°. For the smooth interface, the -3 dB width...

Natural convection of Al2O3-water nanofluid in a wavy enclosure

Science.gov (United States)

Leonard, Mitchell; Mozumder, Aloke K.; Mahmud, Shohel; Das, Prodip K.

2017-06-01

Natural convection heat transfer and fluid flow inside enclosures filled with fluids, such as air, water or oil, have been extensively analysed for thermal enhancement and optimisation due to their applications in many engineering problems, including solar collectors, electronic cooling, lubrication technologies, food processing and nuclear reactors. In comparison, little effort has been given to the problem of natural convection inside enclosures filled with nanofluids, while the addition of nanoparticles into a fluid base to alter thermal properties can be a feasible solution for many heat transfer problems. In this study, the problem of natural convection heat transfer and fluid flow inside a wavy enclosure filled with Al2O3-water nanofluid is investigated numerically using ANSYS-FLUENT. The effects of surface waviness and aspect ratio of the wavy enclosure on the heat transfer and fluid flow are analysed for various concentrations of Al2O3 nanoparticles in water. Flow fields and temperature fields are investigated and heat transfer rate is examined for different values of Rayleigh number. Results show that heat transfer within the enclosure can be enhanced by increasing surface waviness, aspect ratio or nanoparticles volume fraction. Changes in surface waviness have little effect on the heat transfer rate at low Rayleigh numbers, but when Ra ≥ 105 heat transfer increases with the increase of surface waviness from zero to higher values. Increasing the aspect ratio causes an increase in heat transfer rate, as the Rayleigh number increases the effect of changing aspect ratio is more apparent with the greatest heat transfer enhancement seen at higher Rayleigh numbers. Nanoparticles volume fraction has a little effect on the average Nusselt number at lower Rayleigh numbers when Ra ≥ 105 average Nusselt number increases with the increase of volume fraction. These findings provide insight into the heat transfer effects of using Al2O3-water nanofluid as a heat

The disposal and reparation of radio-active enclosures

International Nuclear Information System (INIS)

Boutot, P.

1964-01-01

The dismantling of active installations with a view to repairing them or disposing of them is an exceptional operation which tends nevertheless to become more frequent as the materials age technically or mechanically. The author describes, after two years experience, the peculiarities of the method for dismantling which is carried out inside sealed enclosures after the contamination has been fixed. (author) [fr

Transfer of toxic and radioactive materials to and from a work enclosure

International Nuclear Information System (INIS)

Hackney, S.

1980-01-01

Apparatus for transfer of toxic and radioactive materials between a work enclosure, e.g. a glove box, and a container for storing and transporting the materials comprises a 'double-cover' through which materials are moved. A port in the enclosure is closed by a first cover and the container is closed by a second cover. During transfer, the covers are connected together and the space between the covers is swept by an air stream supplied by a pipe to prevent ingress and deposition of toxic or radioactive material on the facing surfaces of the cover which are subsequently exposed to the environment on separation of the covers. (author)

Point and planar LIF for velocity-concentration correlations in a jet in cross flow

DEFF Research Database (Denmark)

Meyer, Knud Erik; Özcan, Oktay; Larsen, Poul Scheel

2002-01-01

Simultaneous measurements of velocities and concentration with Planar Laser Induced Fluorescense (PLIF) combined with Particle Image Velocimetry (PIV) are compared to similar measurements with pointwise Laser Induced Fluorescense (LIF) made with a slightly modified standard Laser Doppler Anemometer......, since these involve areas with high velocity- and concentration gradients, which in turn amplifies the effect of a finite measurement volume in the two measurement systems. In addition, the concentration measurement was realized by injecting clean water into the dye seeded main flow. This "inverse...

High rabbit abundance proves detrimental to the population growth rate in European rabbit (Oryctolagus cuniculus L. extensive breeding enclosures

Directory of Open Access Journals (Sweden)

L. Ruiz-Aizpurua

2014-09-01

Full Text Available The European rabbit (Oryctolagus cuniculus L. is a key prey species in Mediterranean ecosystems that has declined in its natural ranges as a result of diseases and loss of habitat. This situation has led to the production of wild rabbits in enclosures in which they can acclimate and breed. The efficiency of these enclosures as extensive breeding systems is defined by their population growth rate (PGR. The aim of this study is to analyse the effect of rabbit abundance on the PGR. This has been done by creating general linear models to explain autumn and spring PGR with the use of rabbit abundance estimates, enclosure size, aerial predation and previous PGR as possible explanatory variables. Rabbit abundance and enclosure size negatively affected the autumn PGR, while only rabbit abundance affected the spring PGR in the best-fit models. It is suggested that maintaining rabbit densities at fewer than 30 rabbits per hectare might help to optimise the efficiency inside enclosures.

Counting convex polygons in planar point sets

NARCIS (Netherlands)

Mitchell, J.S.B.; Rote, G.; Sundaram, Gopalakrishnan; Woeginger, G.J.

1995-01-01

Given a set S of n points in the plane, we compute in time O(n3) the total number of convex polygons whose vertices are a subset of S. We give an O(m · n3) algorithm for computing the number of convex k-gons with vertices in S, for all values k = 3,…, m; previously known bounds were exponential

Discrete approach to complex planar geometries

International Nuclear Information System (INIS)

Cupini, E.; De Matteis, A.

1974-01-01

Planar regions in Monte Carlo transport problems have been represented by a finite set of points with a corresponding region index for each. The simulation of particle free-flight reduces then to the simple operations necessary for scanning appropriate grid points to determine whether a region other than the starting one is encountered. When the complexity of the geometry is restricted to only some regions of the assembly examined, a mixed discrete-continuous philosophy may be adopted. By this approach, the lattice of a thermal reactor has been treated, discretizing only the central regions of the cell containing the fuel rods. Excellent agreement with experimental results has been obtained in the computation of cell parameters in the energy range from fission to thermalization through the 238 U resonance region. (U.S.)

Non-planar ABJ theory and parity

International Nuclear Information System (INIS)

Caputa, Pawel; Kristjansen, Charlotte; Zoubos, Konstantinos

2009-01-01

While the ABJ Chern-Simons-matter theory and its string theory dual manifestly lack parity invariance, no sign of parity violation has so far been observed on the weak coupling spin chain side. In particular, the planar two-loop dilatation generator of ABJ theory is parity invariant. In this Letter we derive the non-planar part of the two-loop dilatation generator of ABJ theory in its SU(2)xSU(2) sub-sector. Applying the dilatation generator to short operators, we explicitly demonstrate that, for operators carrying excitations on both spin chains, the non-planar part breaks parity invariance. For operators with only one type of excitation, however, parity remains conserved at the non-planar level. We furthermore observe that, as for ABJM theory, the degeneracy between planar parity pairs is lifted when non-planar corrections are taken into account.

Non-planar ABJ Theory and Parity

DEFF Research Database (Denmark)

Caputa, Pawel; Kristjansen, Charlotte; Zoubos, Konstantinos

2009-01-01

we derive the non-planar part of the two-loop dilatation generator of ABJ theory in its SU(2)xSU(2) sub-sector. Applying the dilatation generator to short operators, we explicitly demonstrate that, for operators carrying excitations on both spin chains, the non-planar part breaks parity invariance......While the ABJ Chern-Simons-matter theory and its string theory dual manifestly lack parity invariance, no sign of parity violation has so far been observed on the weak coupling spin chain side. In particular, the planar two-loop dilatation generator of ABJ theory is parity invariant. In this letter....... For operators with only one type of excitation, however, parity remains conserved at the non-planar level. We furthermore observe that, as for ABJM theory, the degeneracy between planar parity pairs is lifted when non-planar corrections are taken into account....

An in-situ measuring method for planar straightness error

Science.gov (United States)

Chen, Xi; Fu, Luhua; Yang, Tongyu; Sun, Changku; Wang, Zhong; Zhao, Yan; Liu, Changjie

2018-01-01

According to some current problems in the course of measuring the plane shape error of workpiece, an in-situ measuring method based on laser triangulation is presented in this paper. The method avoids the inefficiency of traditional methods like knife straightedge as well as the time and cost requirements of coordinate measuring machine(CMM). A laser-based measuring head is designed and installed on the spindle of a numerical control(NC) machine. The measuring head moves in the path planning to measure measuring points. The spatial coordinates of the measuring points are obtained by the combination of the laser triangulation displacement sensor and the coordinate system of the NC machine, which could make the indicators of measurement come true. The method to evaluate planar straightness error adopts particle swarm optimization(PSO). To verify the feasibility and accuracy of the measuring method, simulation experiments were implemented with a CMM. Comparing the measurement results of measuring head with the corresponding measured values obtained by composite measuring machine, it is verified that the method can realize high-precise and automatic measurement of the planar straightness error of the workpiece.

A location procedure for sound sources in reactor-technical enclosures

International Nuclear Information System (INIS)

Hamann, D.

1982-07-01

A passive method requiring one detector only has been developed for the location of sound emitting faults in nuclear power plant components. It is adapted for use in a frequency range the wavelength of which is of the same order of magnitude as characteristic dimensions of the considered enclosure. The location is performed in the following way: (1) For a fixed detector position the Auto Power Spectral Density (APSD) of the source to be located is measured. (2) For this detector position the APSD is calculated for the potential source locations. For this, the free-field APSD as well as the acoustic normal modes of the enclosure are necessary. (3) The measured APSD is compared with the theoretically obtained APSD's. (4) That APSD is determined which is most similar to the measured APSD, and consequently an information about the unknown source position is got. (author)

GAM-HEAT -- a computer code to compute heat transfer in complex enclosures

International Nuclear Information System (INIS)

Cooper, R.E.; Taylor, J.R.; Kielpinski, A.L.; Steimke, J.L.

1991-02-01

The GAM-HEAT code was developed for heat transfer analyses associated with postulated Double Ended Guillotine Break Loss Of Coolant Accidents (DEGB LOCA) resulting in a drained reactor vessel. In these analyses the gamma radiation resulting from fission product decay constitutes the primary source of energy as a function of time. This energy is deposited into the various reactor components and is re- radiated as thermal energy. The code accounts for all radiant heat exchanges within and leaving the reactor enclosure. The SRS reactors constitute complex radiant exchange enclosures since there are many assemblies of various types within the primary enclosure and most of the assemblies themselves constitute enclosures. GAM-HEAT accounts for this complexity by processing externally generated view factors and connectivity matrices, and also accounts for convective, conductive, and advective heat exchanges. The code is applicable for many situations involving heat exchange between surfaces within a radiatively passive medium. The GAM-HEAT code has been exercised extensively for computing transient temperatures in SRS reactors with specific charges and control components. Results from these computations have been used to establish the need for and to evaluate hardware modifications designed to mitigate results of postulated accident scenarios, and to assist in the specification of safe reactor operating power limits. The code utilizes temperature dependence on material properties. The efficiency of the code has been enhanced by the use of an iterative equation solver. Verification of the code to date consists of comparisons with parallel efforts at Los Alamos National Laboratory and with similar efforts at Westinghouse Science and Technology Center in Pittsburgh, PA, and benchmarked using problems with known analytical or iterated solutions. All comparisons and tests yield results that indicate the GAM-HEAT code performs as intended

Numerical Study of Natural Convection within a Wavy Enclosure Using Meshfree Approach: Effect of Corner Heating

Directory of Open Access Journals (Sweden)

Sonam Singh

2014-01-01

Full Text Available This paper presents a numerical study of natural convection within a wavy enclosure heated via corner heating. The considered enclosure is a square enclosure with left wavy side wall. The vertical wavy wall of the enclosure and both of the corner heaters are maintained at constant temperature, Tc and Th, respectively, with Th>Tc while the remaining horizontal, bottom, top and side walls are insulated. A penalty element-free Galerkin approach with reduced gauss integration scheme for penalty terms is used to solve momentum and energy equations over the complex domain with wide range of parameters, namely, Rayleigh number (Ra, Prandtl number (Pr, and range of heaters in the x- and y-direction. Numerical results are represented in terms of isotherms, streamlines, and Nusselt number. It is observed that the rate of heat transfer depends to a great extent on the Rayleigh number, Prandtl number, length of the corner heaters and the shape of the heat transfer surface. The consistent performance of the adopted numerical procedure is verified by comparison of the results obtained through the present meshless technique with those existing in the literature.

Approaches for quantifying reactive and low-volatility biogenic organic compound emissions by vegetation enclosure techniques - part A.

Science.gov (United States)

Ortega, John; Helmig, Detlev

2008-06-01

The high reactivity and low vapor pressure of many biogenic volatile organic compounds (BVOC) make it difficult to measure whole-canopy fluxes of BVOC species using common analytical techniques. The most appropriate approach for estimating these BVOC fluxes is to determine emission rates from dynamic vegetation enclosure measurements. After scaling leaf- and branch-level emission rates to the canopy level, these fluxes can then be used in models to determine BVOC influences on atmospheric chemistry and aerosol processes. Previously published reports from enclosure measurements show considerable variation among procedures with limited guidelines or standard protocols to follow. This article reviews this literature and describes the variety of enclosure types, materials, and analysis techniques that have been used to determine BVOC emission rates. The current review article is followed by a companion paper which details a comprehensive enclosure technique that incorporates both recommendations from the literature as well as insight gained from theoretical calculations and practical experiences. These methods have yielded new BVOC emission data for highly reactive monoterpenes (MT) and sesquiterpenes (SQT) from a variety of vegetation species.

Feasibility of motion laws for planar one degree of freedom linkage mechanisms at dead point configurations

Science.gov (United States)

Lores García, E.; Veciana Fontanet, J. M.; Jordi Nebot, L.

2018-01-01

This paper proposes an analytical solution of the Inverse Kinematics (IK) problem at dead point configurations for any planar one degree of freedom linkage mechanism, with regard to the continuity Cn of the motion law. The systems analyzed are those whose elements are linked with lower pairs and do not present redundancies. The study aims to provide the user with some rules to facilitate the design of feasible motion profiles to be reproduced by conventional electrical actuators at these configurations. During the last decades, several methods and techniques have been developed to study this specific configuration. However, these techniques are mainly focused on solving numerically the IK indeterminacy, rather than analyzing the motion laws that the mechanisms are able to perform at these particular configurations. The analysis presented in this paper has been carried out differentiating and applying l'Hôpital's rule to the system of constraint equations ϕ (q) of the mechanism. The study also considers the feasibility of the time-domain profiles to be reproduced with conventional electrical actuators (i.e. AC/DC motors, linear actuators, etc.). To show the usefulness and effectiveness of the method, the development includes the analytical application and numerical simulations for two common one degree of freedom systems: a slider-crank and a four linkage mechanisms. Finally, experimental results are presented on a four linkage mechanism test bed.

An Efficient Method for Synthesis of Planar Multibody Systems including Shape of Bodies as Design Variables

DEFF Research Database (Denmark)

Hansen, Michael R.; Hansen, John Michael

1998-01-01

A point contact joint has been developed and implemented in a joint coordinate based planar multibody dynamics analysis program that also supports revolute and translational joints. Further, a segment library for the definition of the contours of the point contact joints has been integrated...

Resistor capacitor, primitive variable solution of buoyant fluid flow within an enclosure with highly temperature dependent viscosity

Energy Technology Data Exchange (ETDEWEB)

Burns, S.P. [Texas Univ., Austin, TX (United States); Gianoulakis, S.E. [Sandia National Labs., Albuquerque, NM (United States)

1995-07-01

A numerical solution for buoyant natural convection within a square enclosure containing a fluid with highly temperature dependent viscosity is presented. Although the fluid properties employed do not represent any real fluid, the large variation in the fluid viscosity with temperature is characteristic of turbulent flow modeling with eddy-viscosity concepts. Results are obtained using a primitive variable formulation and the resistor method. The results presented include velocity, temperature and pressure distributions within the enclosure as well as shear stress and heat flux distributions along the enclosure walls. Three mesh refinements were employed and uncertainty values are suggested for the final mesh refinement. These solutions are part of a contributed benchmark solution set for the subject problem.

AN ADAPTIVE APPROACH FOR SEGMENTATION OF 3D LASER POINT CLOUD

Directory of Open Access Journals (Sweden)

Z. Lari

2012-09-01

Full Text Available Automatic processing and object extraction from 3D laser point cloud is one of the major research topics in the field of photogrammetry. Segmentation is an essential step in the processing of laser point cloud, and the quality of extracted objects from laser data is highly dependent on the validity of the segmentation results. This paper presents a new approach for reliable and efficient segmentation of planar patches from a 3D laser point cloud. In this method, the neighbourhood of each point is firstly established using an adaptive cylinder while considering the local point density and surface trend. This neighbourhood definition has a major effect on the computational accuracy of the segmentation attributes. In order to efficiently cluster planar surfaces and prevent introducing ambiguities, the coordinates of the origin's projection on each point's best fitted plane are used as the clustering attributes. Then, an octree space partitioning method is utilized to detect and extract peaks from the attribute space. Each detected peak represents a specific cluster of points which are located on a distinct planar surface in the object space. Experimental results show the potential and feasibility of applying this method for segmentation of both airborne and terrestrial laser data.

Evaluation of climatic vibration testing on plastic waterproof enclosure for electronic equipment using ANSYS[reg] workbench

International Nuclear Information System (INIS)

Aw, K.C.; Huang, W.D.J.; De Silva, M.W.R.P.

2007-01-01

Designing and testing of waterproof enclosure for electronic equipment involves significant amount of time and resources. This paper concentrates on electronic equipment used for maritime application. Typical waterproof test perform is based on the IEC 60529 standards and is insufficient to determine its reliability. Since, these enclosures were subjected to environmental stress such as heat and vibration and there is a need to understand how these affect the waterproof performance. Simulation using ANSYS workbench software was performed to comprehend the effect of various parameters of accelerated testing performed on these waterproof enclosures. Experiments were performed to examine the correlation with simulation results. The results confirmed that accelerated testing with random vibration at cold temperature causes greatest stress and causes degradation to adhesive bonds and hence affect the waterproof performance

Analytical Modeling of Natural Convection in a Tall Rectangular Enclosure with Multiple Disconnected Partitions

Directory of Open Access Journals (Sweden)

Youngmin Bae

2016-08-01

Full Text Available In this study, laminar natural circulation and heat transfer in a tall rectangular enclosure with disconnected vertical partitions inside were investigated. Analytical expressions were developed to predict the circulation flow rate and the average Nusselt number in a partially partitioned enclosure with isothermal side walls at different temperatures and insulated top and bottom walls. The proposed formulas are then validated against numerical results for modified Rayleigh numbers of up to 106. The impacts of the governing parameters are also examined along with a discussion of the heat transfer regimes.

Dynamics of Equilibrium Points in a Uniformly Rotating Second-Order and Degree Gravitational Field

Science.gov (United States)

Feng, Jinglang; Hou, Xiyun

2017-07-01

Using tools such as periodic orbits and invariant manifolds, the global dynamics around equilibrium points (EPs) in a rotating second-order and degree gravitational field are studied. For EPs on the long axis, planar and vertical periodic families are computed, and their stability properties are investigated. Invariant manifolds are also computed, and their relation to the first-order resonances is briefly discussed. For EPs on the short axis, planar and vertical periodic families are studied, with special emphasis on the genealogy of the planar periodic families. Our studies show that the global dynamics around EPs are highly similar to those around libration points in the circular restricted three-body problem, such as spatial halo orbits, invariant manifolds, and the genealogy of planar periodic families.

Planar graphs theory and algorithms

CERN Document Server

Nishizeki, T

1988-01-01

Collected in this volume are most of the important theorems and algorithms currently known for planar graphs, together with constructive proofs for the theorems. Many of the algorithms are written in Pidgin PASCAL, and are the best-known ones; the complexities are linear or 0(nlogn). The first two chapters provide the foundations of graph theoretic notions and algorithmic techniques. The remaining chapters discuss the topics of planarity testing, embedding, drawing, vertex- or edge-coloring, maximum independence set, subgraph listing, planar separator theorem, Hamiltonian cycles, and single- or multicommodity flows. Suitable for a course on algorithms, graph theory, or planar graphs, the volume will also be useful for computer scientists and graph theorists at the research level. An extensive reference section is included.

Process and device for leak rate measurement of an enclosure

International Nuclear Information System (INIS)

Giroux, J.

1989-01-01

The volume of a cavity, such as a cylinder and a piston, connected to the enclosure (glovebox or reactor containment shell) is varied to find back the previous pressure difference with the outside (positive or negative). Thermometers and a barometer are provided for eventual corrections [fr

Cache-Oblivious Planar Orthogonal Range Searching and Counting

DEFF Research Database (Denmark)

Arge, Lars; Brodal, Gerth Stølting; Fagerberg, Rolf

2005-01-01

present the first cache-oblivious data structure for planar orthogonal range counting, and improve on previous results for cache-oblivious planar orthogonal range searching. Our range counting structure uses O(Nlog2 N) space and answers queries using O(logB N) memory transfers, where B is the block...... size of any memory level in a multilevel memory hierarchy. Using bit manipulation techniques, the space can be further reduced to O(N). The structure can also be modified to support more general semigroup range sum queries in O(logB N) memory transfers, using O(Nlog2 N) space for three-sided queries...... and O(Nlog22 N/log2log2 N) space for four-sided queries. Based on the O(Nlog N) space range counting structure, we develop a data structure that uses O(Nlog2 N) space and answers three-sided range queries in O(logB N+T/B) memory transfers, where T is the number of reported points. Based...

Shielded enclosure for handling radioactive material; Sorbonnes blindees pour manipulations radioactives

Energy Technology Data Exchange (ETDEWEB)

Laurent, H; Courouble, J M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1959-07-01

Two enclosures linked by an air-lock are described: they are designed for the safe handling of 5 curies 0.3 to 0.5 MeV {gamma} emitters, and each is composed of a semi-tight case, ventilated, clad in 80 mm steel plate, and suited for a wide variety of physics and chemistry operations. The equipment required for any given operation can be installed in the shortest possible time, access to the enclosure being via a removable front. Visual control is assured through a lead-glass screen. Each enclosure is fitted with a master-slave manipulator, Argon model 7, and plugs and air-locks are provided for the introduction of liquids and solids. (author) [French] On decrit deux enceintes reliees par un sas pour manipulation sur 5 curies d'emetteurs {gamma} de 0,3 a 0,5 MeV. Chacune des enceintes est constituee d'une boite semi-etanche, ventilee, entouree de toles d'acier de 80 mm. L'ensemble est concu pour y effectuer les operations physiques ou chimiques les plus variees. L'equipement necessaire a une manipulation donnee peut y etre installe dans le minimum de temps, l'acces se faisant par la face avant qui peut se deplacer. Une dalle de verre au plomb assure la vision. Chacune des sorbonnes est equipee d'une paire de telemanipulateurs Argonne modele 7. Des sas et des bouchons assurent le passage des solides et des fluides. (auteur)

Effectiveness of pads and enclosures as safety interventions on consumer trampolines

Science.gov (United States)

Eager, David; Scarrott, Carl; Sushinsky, George

2010-01-01

Background Trampolines continue to be a major source of childhood injury. Objective To examine available data on trampoline injuries in order to determine the effectiveness of padding and enclosures. Design Trampoline injuries from the NEISS database from 2002 to 2007 were reclassified into five cause-categories, to examine evidence for injury trends. Setting The ASTM trampoline standard recommendations for safety padding were upgraded in 1999 and enclosures were introduced in 1997. This is the first study to examine the impact of these changes. Patients The sampling frame comprises patients with NEISS product code ‘consumer trampolines’ (1233). A systematic sample of 360 patients each year is taken. Interventions The prominent interventions recommended by the ASTM are netting enclosures to prevent falling off and safety padding to cover frames and springs. Main outcome measures Proportion of injuries within each cause-category and trend estimates. Results There was no evidence for a decline within the injury cause-categories that should be prevented by these interventions from 2002 to 2007. Conclusions If these interventions were effective the associated injury causes would be in decline. Instead they remain close to half of all trampoline injuries with no significant change over the period of the study. Follow-up studies are proposed to determine the reasons. Given the number of injuries involved it is recommended that steps be taken to ensure these safety interventions or their equivalents are in place, work properly and remain effective for the life of consumer trampolines. PMID:20570986

Multi-Class Simultaneous Adaptive Segmentation and Quality Control of Point Cloud Data

Directory of Open Access Journals (Sweden)

Ayman Habib

2016-01-01

Full Text Available 3D modeling of a given site is an important activity for a wide range of applications including urban planning, as-built mapping of industrial sites, heritage documentation, military simulation, and outdoor/indoor analysis of airflow. Point clouds, which could be either derived from passive or active imaging systems, are an important source for 3D modeling. Such point clouds need to undergo a sequence of data processing steps to derive the necessary information for the 3D modeling process. Segmentation is usually the first step in the data processing chain. This paper presents a region-growing multi-class simultaneous segmentation procedure, where planar, pole-like, and rough regions are identified while considering the internal characteristics (i.e., local point density/spacing and noise level of the point cloud in question. The segmentation starts with point cloud organization into a kd-tree data structure and characterization process to estimate the local point density/spacing. Then, proceeding from randomly-distributed seed points, a set of seed regions is derived through distance-based region growing, which is followed by modeling of such seed regions into planar and pole-like features. Starting from optimally-selected seed regions, planar and pole-like features are then segmented. The paper also introduces a list of hypothesized artifacts/problems that might take place during the region-growing process. Finally, a quality control process is devised to detect, quantify, and mitigate instances of partially/fully misclassified planar and pole-like features. Experimental results from airborne and terrestrial laser scanning as well as image-based point clouds are presented to illustrate the performance of the proposed segmentation and quality control framework.

Enhancing monochromatic multipole emission by a subwavelength enclosure of degenerate Mie resonances

KAUST Repository

Zhao, Jiajun; Zhang, Likun; Wu, Ying

2017-01-01

of the enclosure, and meanwhile the radiation directivity pattern is well preserved. The degeneracy is theoretically analyzed. A realization of the material is suggested by using a space-coiling structure.

Components for containment enclosures. Part 4: Ventilation and gas-cleaning systems such as filters, traps, safety and regulation valves, control and protection devices

International Nuclear Information System (INIS)

2001-01-01

ISO 11933 consists of the following parts, under the general title Components for containment enclosures: Part 1: Glove/bag ports, bungs for glove/bag ports, enclosure rings and interchangeable units; Part 2: Gloves, welded bags, gaiters for remote-handling tongs and for manipulators; Part 3: Transfer systems such as plain doors, airlock chambers, double door transfer systems, leaktight connections for waste drums; Part 4: Ventilation and gas-cleaning systems such as filters, traps, safety and regulation valves, control and protection devices; Part 5: Penetrations for electrical and fluid circuits. This part of ISO 11933 specifies the design criteria and the characteristics of various components used for ventilation and gas-cleaning in containment enclosures. These components are either directly fixed to the containment enclosure wall, or used in the environment of a shielded or unshielded containment enclosure or line of such enclosures. They can be used alone or in conjunction with other mechanical components, including those specified in ISO 11933-1 and ISO 11933-3. This part of ISO 11933 is applicable to: filtering devices, including high-efficiency particulate air (HEPA) filters and iodine traps; safety valves and pressure regulators; systems ensuring the mechanical protection of containment enclosures; control and pressure-measurement devices

Development of enclosure technique of tag gas for in-pile creep test

International Nuclear Information System (INIS)

Izaki, Toru; Ichikawa, Shoichi; Soroi, Masatoshi; Ito, Chikara

2004-01-01

Outline of the enclosure technique of tag gas for in-pile creep test is stated. In order to carry out in-pile creep test, the sample can enclose tag gas before the test and then the sample is inserted into MARICO-2 (Material Testing Rig with Temperature Control) in FBR 'JOYO' MK-III for the irradiation test. Outline of in-pile creep test using tag gas, enclosure system of tag gas, detection of a part of broken sample and identification of sample are explained. 126-, 128-, 129-, 131-, 132-, and 134-Xe are used as tag gases. The samples are identified by RIMS (Laser Resonance Ionization Mass Spectroscopy) in ppt order. ODS ferritic steel will be tested by the method in the next step. (S.Y.)

In vitro quantification of the performance of model-based mono-planar and bi-planar fluoroscopy for 3D joint kinematics estimation.

Science.gov (United States)

Tersi, Luca; Barré, Arnaud; Fantozzi, Silvia; Stagni, Rita

2013-03-01

Model-based mono-planar and bi-planar 3D fluoroscopy methods can quantify intact joints kinematics with performance/cost trade-off. The aim of this study was to compare the performances of mono- and bi-planar setups to a marker-based gold-standard, during dynamic phantom knee acquisitions. Absolute pose errors for in-plane parameters were lower than 0.6 mm or 0.6° for both mono- and bi-planar setups. Mono-planar setups resulted critical in quantifying the out-of-plane translation (error bi-planar in quantifying the rotation along bone longitudinal axis (error bi-planar (error comparable to bi-planar, but with halved computational costs, halved segmentation time and halved ionizing radiation dose. Bi-planar analysis better compensated for the out-of-plane uncertainty that is differently propagated to relative kinematics depending on the setup. To take its full benefits, the motion task to be investigated should be designed to maintain the joint inside the visible volume introducing constraints with respect to mono-planar analysis.

The Effects of Spatial Enclosure on Social Interaction Between Older Adults With Dementia and Young Children.

Science.gov (United States)

Cerruti, Minyoung S; Shepley, Mardelle M

2016-04-01

To examine the impact of spatial enclosures on social interaction between older adults with early stage dementia and young children. Intergenerational interaction through meaningful activities can promote positive affects and behaviors of children and older adults. The development of social interaction is closely related to the physical environment in association with personal competence of older adults with dementia and young children. However, minimal attention has been given to the role of physical environment in influencing intergenerational interaction. A quasi-experiment examined the functional relationship between the amount of spatial enclosure and the types of social behaviors of older adults with dementia and young children. Semi-structured interviews, aided by a photographic simulation, were developed to explore the participants' perceptions of and experiences with the different degrees of spatial enclosure. Findings showed that the semienclosed spatial plan impacted both prosocial and antisocial behaviors of older adults with dementia in their interactions with young children. This apparent discrepancy was associated with two conflicting perceptions: a sense of openness and the lack of control due to distraction created by the loose visual boundary. There was no correlation between the elder-child neutral behaviors and the degrees of spatial enclosure. This study suggests that spaces with moderate openness without visual and acoustic distraction are the most desirable to promote prosocial behaviors of older adults with dementia and young children. Additionally, elder-child prosocial behaviors were likely facilitated by specific design features such as adequate personal space, the perception of openness, and possible spaces that provide both prospect and refuge in relation to spatial enclosure. © The Author(s) 2016.

The Prohibitive Link between Position-based Routing and Planarity

Directory of Open Access Journals (Sweden)

David Cairns

2013-12-01

Full Text Available Position-based routing is touted as an ideal routing strategy for resource-constrained wireless networks. One persistent barrier to adoption is due to its recovery phase, where messages are forwarded according to leftor right-hand rule (LHR. This is often referred to as face-routing. In this paper we investigate the limits of LHR with respect to planarity.We show that the gap between non-planarity and successful delivery is a single link within a single configuration. Our work begins with an analysis to enumerate all node configurations that cause intersections in the unit-disc graph. We find that left-hand rule is able to recover from all but a single case, the ‘umbrella’ configuration so named for its appearance. We use this information to propose the Prohibitive Link Detection Protocol (PLDP that can guarantee delivery over non-planar graphs using standard face-routing techniques. As the name implies, the protocol detects and circumvents the ‘bad’ links that hamper LHR. The goal of this work is to maintain routing guarantees while disturbing the network graph as little as possible. In doing so, a new starting point emerges from which to build rich distributed protocols in the spirit of CLDP and GDSTR.

Distribution of quantum states in enclosures of finite size I

International Nuclear Information System (INIS)

Souto, J.H.; Chaba, A.N.

1989-01-01

The expression for the density of states of a particle in a three-dimensional rectangular box of finite size can be obtained directly by Poissons's Summation formula. The expression for the case of an enclosure in the form of an infinite rectangular slab is derived. (A.C.A.S.) [pt

Dynamics of Equilibrium Points in a Uniformly Rotating Second-Order and Degree Gravitational Field

Energy Technology Data Exchange (ETDEWEB)

Feng, Jinglang; Hou, Xiyun, E-mail: jinglang@nju.edu.cn, E-mail: silence@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, 210093 (China)

2017-07-01

Using tools such as periodic orbits and invariant manifolds, the global dynamics around equilibrium points (EPs) in a rotating second-order and degree gravitational field are studied. For EPs on the long axis, planar and vertical periodic families are computed, and their stability properties are investigated. Invariant manifolds are also computed, and their relation to the first-order resonances is briefly discussed. For EPs on the short axis, planar and vertical periodic families are studied, with special emphasis on the genealogy of the planar periodic families. Our studies show that the global dynamics around EPs are highly similar to those around libration points in the circular restricted three-body problem, such as spatial halo orbits, invariant manifolds, and the genealogy of planar periodic families.

Dynamics of Equilibrium Points in a Uniformly Rotating Second-Order and Degree Gravitational Field

International Nuclear Information System (INIS)

Feng, Jinglang; Hou, Xiyun

2017-01-01

Using tools such as periodic orbits and invariant manifolds, the global dynamics around equilibrium points (EPs) in a rotating second-order and degree gravitational field are studied. For EPs on the long axis, planar and vertical periodic families are computed, and their stability properties are investigated. Invariant manifolds are also computed, and their relation to the first-order resonances is briefly discussed. For EPs on the short axis, planar and vertical periodic families are studied, with special emphasis on the genealogy of the planar periodic families. Our studies show that the global dynamics around EPs are highly similar to those around libration points in the circular restricted three-body problem, such as spatial halo orbits, invariant manifolds, and the genealogy of planar periodic families.

Theoretical study on dynamical planar-chirality switching in checkerboard-like metasurfaces

Directory of Open Access Journals (Sweden)

Urade Yoshiro

2017-01-01

Full Text Available In this paper, we show that the handedness of a planar chiral checkerboard-like metasurface can be dynamically switched by modulating the local sheet impedance of the metasurface structure. We propose a metasurface design to realize the handedness switching and theoretically analyze its electromagnetic characteristic based on Babinet’s principle. Numerical simulations of the proposed metasurface are performed to validate the theoretical analysis. It is demonstrated that the polarity of asymmetric transmission for circularly polarized waves, which is determined by the planar chirality of the metasurface, is inverted by switching the sheet impedance at the interconnection points of the checkerboard-like structure. The physical origin of the asymmetric transmission is also discussed in terms of the surface current and charge distributions on the metasurface.

Turbulence modeling of natural convection in enclosures: A review

International Nuclear Information System (INIS)

Choi, Seok Ki; Kim, Seong O

2012-01-01

In this paper a review of recent developments of turbulence models for natural convection in enclosures is presented. The emphasis is placed on the effect of the treatments of Reynolds stress and turbulent heat flux on the stability and accuracy of the solution for natural convection in enclosures. The turbulence models considered in the preset study are the two-layer k -ε model, the shear stress transport (SST) model, the elliptic-relaxation (V2-f) model and the elliptic-blending second-moment closure (EBM). Three different treatments of the turbulent heat flux are the generalized gradient diffusion hypothesis (GGDH), the algebraic flux model (AFM) and the differential flux model (DFM). The mathematical formulation of the above turbulence models and their solution method are presented. Evaluation of turbulence models are performed for turbulent natural convection in a 1:5 rectangular cavity ( Ra = 4.3x10 10 ) and in a square cavity with conducting top and bottom walls ( Ra =1.58x10 9 ) and the Rayleigh-Benard convection ( Ra = 2x10 6 ∼ Ra =10 9 ). The relative performances of turbulence models are examined and their successes and shortcomings are addressed

Magnetometric prospection of various types of large ditched enclosures in Bohemia

Czech Academy of Sciences Publication Activity Database

Křivánek, Roman

2006-01-01

Roč. 13, č. 1 (2006), s. 25-43 ISSN 1075-2196 R&D Projects: GA ČR GV404/97/K024 Institutional research plan: CEZ:AV0Z80020508 Keywords : prospection * ditch enclosure * magnetometer Subject RIV: AC - Archeology, Anthropology, Ethnology

Safety of stationary grinding machines - impact resistance of work zone enclosures.

Science.gov (United States)

Mewes, Detlef; Adler, Christian

2017-09-01

Guards on machine tools are intended to protect persons from being injured by parts ejected with high kinetic energy from the work zone of the machine. Stationary grinding machines are a typical example. Generally such machines are provided with abrasive product guards closely enveloping the grinding wheel. However, many machining tasks do not allow the use of abrasive product guards. In such cases, the work zone enclosure has to be dimensioned so that, in case of failure, grinding wheel fragments remain inside the machine's working zone. To obtain data for the dimensioning of work zone enclosures on stationary grinding machines, which must be operated without an abrasive product guard, burst tests were conducted with vitrified grinding wheels. The studies show that, contrary to widely held opinion, narrower grinding wheels can be more critical concerning the impact resistance than wider wheels although their fragment energy is smaller.

EQPlanar: a maximum-likelihood method for accurate organ activity estimation from whole body planar projections

International Nuclear Information System (INIS)

Song, N; Frey, E C; He, B; Wahl, R L

2011-01-01

Optimizing targeted radionuclide therapy requires patient-specific estimation of organ doses. The organ doses are estimated from quantitative nuclear medicine imaging studies, many of which involve planar whole body scans. We have previously developed the quantitative planar (QPlanar) processing method and demonstrated its ability to provide more accurate activity estimates than conventional geometric-mean-based planar (CPlanar) processing methods using physical phantom and simulation studies. The QPlanar method uses the maximum likelihood-expectation maximization algorithm, 3D organ volume of interests (VOIs), and rigorous models of physical image degrading factors to estimate organ activities. However, the QPlanar method requires alignment between the 3D organ VOIs and the 2D planar projections and assumes uniform activity distribution in each VOI. This makes application to patients challenging. As a result, in this paper we propose an extended QPlanar (EQPlanar) method that provides independent-organ rigid registration and includes multiple background regions. We have validated this method using both Monte Carlo simulation and patient data. In the simulation study, we evaluated the precision and accuracy of the method in comparison to the original QPlanar method. For the patient studies, we compared organ activity estimates at 24 h after injection with those from conventional geometric mean-based planar quantification using a 24 h post-injection quantitative SPECT reconstruction as the gold standard. We also compared the goodness of fit of the measured and estimated projections obtained from the EQPlanar method to those from the original method at four other time points where gold standard data were not available. In the simulation study, more accurate activity estimates were provided by the EQPlanar method for all the organs at all the time points compared with the QPlanar method. Based on the patient data, we concluded that the EQPlanar method provided a

Transmutation of planar media singularities in a conformal cloak.

Science.gov (United States)

Liu, Yichao; Mukhtar, Musawwadah; Ma, Yungui; Ong, C K

2013-11-01

Invisibility cloaking based on optical transformation involves materials singularity at the branch cut points. Many interesting optical devices, such as the Eaton lens, also require planar media index singularities in their implementation. We show a method to transmute two singularities simultaneously into harmless topological defects formed by anisotropic permittivity and permeability tensors. Numerical simulation is performed to verify the functionality of the transmuted conformal cloak consisting of two kissing Maxwell fish eyes.

Decay of reverberant sound in a spherical enclosure

International Nuclear Information System (INIS)

Carroll, M.M.; Chien, C.F.

1977-01-01

The assumption of diffuse reflection (Lambert's Law) leads to integral equations for the wall intensity in a reverberant sound field in the steady state and during decay. The latter equation, in the special case of a spherical enclosure with uniformly absorbent walls and uniform wall intensity, allows exponential decay with a decay time which agrees closely with the Norris--Eyring prediction. The sound-intensity and sound-energy density in the medium, during decay, are also calculated

Co-planar deformation and thermal propagation behavior in a bundle burst test

International Nuclear Information System (INIS)

Uetsuka, Hiroshi; Koizumi, Yasuo; Kawasaki, Satoru

1980-07-01

The probability of the suggested feedback mechanism which could lead to co-planar deformation in a bundle burst test was assessed by the data of test and the calculation based on simplified model. Following four points were evaluated. (1) The probability of local deformation during early heat up stage. (2) The relation between the characteristic of heater and the feedback mechanism. (3) Thermal propagation behavior between two adjacent rods during heat up stage. (4) The propagation of ballooning in a bundle. The probability of suggested feedback mechanism was denied in all the evaluation. The feedback mechanism suggested by Burman could not be a controlling mechanism in co-planar deformation in a bundle burst test. (author)

NIR luminescent Er{sup 3+}/Yb{sup 3+} co-doped SiO{sub 2}-ZrO{sub 2} nanostructured planar and channel waveguides: Optical and structural properties

Energy Technology Data Exchange (ETDEWEB)

Cunha, Cesar dos Santos [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto/SP (Brazil); Ferrari, Jefferson Luis [Grupo de Pesquisa em Quimica de Materiais - (GPQM), Departamento de Ciencias Naturais, Universidade Federal de Sao Joao Del Rei, Campus Dom Bosco, Praca Dom Helvecio, 74, 36301-160, Sao Joao Del Rei, MG (Brazil); Oliveira, Drielly Cristina de [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto/SP (Brazil); Maia, Lauro June Queiroz [Grupo Fisica de Materiais, Instituto de Fisica, UFG, Campus Samambaia, Caixa Postal 131, 74001-970, Goiania/GO (Brazil); Gomes, Anderson Stevens Leonidas [Departamento de Fisica, Universidade Federal de Pernambuco, Cidade Universitaria, Recife/PE, 50670-901 (Brazil); Ribeiro, Sidney Jose Lima [Laboratorio de Materiais Fotonicos, Instituto de Quimica, UNESP, Caixa Postal 355, 14801-970, Araraquara/SP (Brazil); and others

2012-09-14

Optical and structural properties of planar and channel waveguides based on sol-gel Er{sup 3+} and Yb{sup 3+} co-doped SiO{sub 2}-ZrO{sub 2} are reported. Microstructured channels with high homogeneous surface profile were written onto the surface of multilayered densified films deposited on SiO{sub 2}/Si substrates by a femtosecond laser etching technique. The densification of the planar waveguides was evaluated from changes in the refractive index and thickness, with full densification being achieved at 900 Degree-Sign C after annealing from 23 up to 500 min, depending on the ZrO{sub 2} content. Crystal nucleation and growth took place together with densification, thereby producing transparent glass ceramic planar waveguides containing rare earth-doped ZrO{sub 2} nanocrystals dispersed in a silica-based glassy host. Low roughness and crack-free surface as well as high confinement coefficient were achieved for all the compositions. Enhanced NIR luminescence of the Er{sup 3+} ions was observed for the Yb{sup 3+}-codoped planar waveguides, denoting an efficient energy transfer from the Yb{sup 3+} to the Er{sup 3+} ion. Highlights: Black-Right-Pointing-Pointer Sol-gel high NIR luminescent nanostructured planar and channel waveguides. Black-Right-Pointing-Pointer Microstructured channels written by a femtosecond laser etching technique. Black-Right-Pointing-Pointer Transparent glass ceramic with rare earth-doped ZrO{sub 2} nanocrystals in a silica host. Black-Right-Pointing-Pointer Enhanced NIR luminescence, efficient energy transfer from the Yb{sup 3+} to the Er{sup 3+} ion. Black-Right-Pointing-Pointer New planar channel waveguides to be applied as EDWA in the C telecommunication band.

Managing socio-institutional enclosure: A grounded theory of caregivers' attentiveness in hospital care.

Science.gov (United States)

Klaver, Klaartje; Baart, Andries

2016-06-01

Caregivers' attentiveness is vital for healthcare quality, yet existing research lacks a specific definition and neglects its different forms and aspects. This paper presents a qualitative, grounded theory of attentiveness in hospital oncology care. Our data show nine types of attentiveness. We answer the question why a caregiver practices one type of attentiveness in a certain situation, and not another type. First, it appears to be of crucial importance whether attentiveness is essential for giving care in the opinion of the caregiver. Second, the focus of attention is essential. Care given by doctors and nurses is always ambivalent; on the one hand, it concerns the body, and on the other hand, it involves the person whom that body belongs to. What is the caregiver (mainly) focused on? The significance of socio-institutional enclosure emerged as a key theme within the findings. Socio-institutional enclosure concerns the space a caregiver may or may not experience to break free from the preponderant institutional orientation towards the physical body of the patient. At the intersection of the influence of socio-institutional enclosure and the substance of the caregivers' concepts of care, three cultures are found that comprise the different types of attentiveness. Copyright © 2016 Elsevier Ltd. All rights reserved.

Compilation and analysis of national and international OPEX for Safe Enclosure prior to decommissioning

International Nuclear Information System (INIS)

Dinner, Paul J.C.; Heimlich, Karel

2016-01-01

Around the world, a large number of aging nuclear plants are approaching final shutdown. While this is largely driven by plants reaching the end of their design life, economic factors such as low gas prices (in North America) and the smaller unit size of early commercial reactors are important contributors to this trend. In several instances, economic pressures have resulted in a need for a more rapid transition to Safe Enclosure than originally anticipated. Thus plans for this transition taking into account experience with Safe Enclosure periods of varying lengths are being actively prepared in many jurisdictions. The IAEA as well as other national and international authorities have long recognized the importance of the topic of Safe Enclosure and provided guidance, and the IAEA has recently undertaken a study of 'Lessons Learned from Deferred Decommissioning of Nuclear Facilities'. Beginning with preliminary experience from Canadian CANDU reactors in extended shutdown or safe enclosure, this paper aims to compare this experience with the larger pool of experience from the international community to: - classify the main issues or themes, - examine means to mitigate these, and - formulate general measures of 'good practice'. Compilation of this experience represents the first steps towards a comprehensive, searchable database potentially of use to many in the decommissioning community. Tabulation and analysis of the complete list (comprising approximately 70 cases) has provided the 'short list' of issues presented in Table 1. Examples of the most important listed issues are discussed. The authors' objective is to stimulate interest in extending this compilation. In this way it will continue to grow and benefit all those preparing for transition to decommissioning. (authors)

Compilation and analysis of national and international OPEX or safe enclosure prior to decommissioning

International Nuclear Information System (INIS)

Dinner, Paul J.C.; Heimlich, Karel

2016-01-01

Around the world, a large number of aging nuclear plants are approaching final shutdown. While this is largely driven by plants reaching the end of their design life, economic factors such as low gas prices (in North America) and the smaller unit size of early commercial reactors are important contributors to this trend. In several instances, economic pressures have resulted in a need for a more rapid transition to Safe Enclosure than originally anticipated. Thus plans for this transition taking into account experience with Safe Enclosure periods of varying lengths are being actively prepared in many jurisdictions. The IAEA as well as other national and international authorities have long recognized the importance of the topic of Safe Enclosure and provided guidance [1-7], and the IAEA has recently undertaken a study of 'Lessons Learned from Deferred Decommissioning of Nuclear Facilities' [8]. Beginning with preliminary experience from Canadian CANDU reactors in extended shutdown or safe enclosure, this paper aims to compare this experience with the larger pool of experience from the international community to: - classify the main issues or themes, - examine means to mitigate these, and - formulate general measures of 'good practice'. Compilation of this experience represents the first steps towards a comprehensive, searchable database potentially of use to many in the decommissioning community. Tabulation and analysis of the complete list (comprising approximately 70 cases) has provided the 'short list' of issues presented. Examples of the most important listed issues are discussed. The authors' objective is to stimulate interest in extending this compilation. In this way it will continue to grow and benefit all those preparing for transition to decommissioning. (authors)

Mobility and Position Error Analysis of a Complex Planar Mechanism with Redundant Constraints

Science.gov (United States)

Sun, Qipeng; Li, Gangyan

2018-03-01

Nowadays mechanisms with redundant constraints have been created and attracted much attention for their merits. The mechanism of the redundant constraints in a mechanical system is analyzed in this paper. A analysis method of Planar Linkage with a repetitive structure is proposed to get the number and type of constraints. According to the difference of applications and constraint characteristics, the redundant constraints are divided into the theoretical planar redundant constraints and the space-planar redundant constraints. And the calculation formula for the number of redundant constraints and type of judging method are carried out. And a complex mechanism with redundant constraints is analyzed of the influence about redundant constraints on mechanical performance. With the combination of theoretical derivation and simulation research, a mechanism analysis method is put forward about the position error of complex mechanism with redundant constraints. It points out the direction on how to eliminate or reduce the influence of redundant constraints.

The existence of trajectories joining critical points

International Nuclear Information System (INIS)

Yu Shuxiang.

1985-01-01

In this paper, using the notion of an isolating block and the concept of canonical regions, three existence criteria of trajectories connecting a pair of critical points of planar differential equations are given. (author)

Design and construction of a 76m long-travel laser enclosure for a space occulter testbed

Science.gov (United States)

Galvin, Michael; Kim, Yunjong; Kasdin, N. Jeremy; Sirbu, Dan; Vanderbei, Robert; Echeverri, Dan; Sagolla, Giuseppe; Rousing, Andreas; Balasubramanian, Kunjithapatham; Ryan, Daniel; Shaklan, Stuart; Lisman, Doug

2016-07-01

Princeton University is upgrading our space occulter testbed. In particular, we are lengthening it to 76m to achieve flightlike Fresnel numbers. This much longer testbed required an all-new enclosure design. In this design, we prioritized modularity and the use of commercial off-the-shelf (COTS) and semi-COTS components. Several of the technical challenges encountered included an unexpected slow beam drift and black paint selection. Herein we describe the design and construction of this long-travel laser enclosure.

Modeling the planar configuration of extraordinary magnetoresistance

International Nuclear Information System (INIS)

El-Ahmar, S; Pozniak, A A

2015-01-01

Recently the planar version of the extraordinary magnetoresistance (EMR) magnetic field sensor has been constructed and verified in practice. Planar configuration of the EMR device gives many technological advantages, it is simpler than the classic and allows one to build the sensor using electric materials of the new type (such as graphene or topological insulators) much easier. In this work the planar configuration of the EMR sensor is investigated by performing computational simulations using the finite element method (FEM). The computational comparison of the planar and classic configurations of EMR is presented using three-dimensional models. Various variants of the geometry of EMR sensor components are pondered and compared in the planar and classic version. Size of the metal overlap is considered for sensor optimization as well as various semiconductor-metal contact resistance dependences of the EMR signal. Based on computational simulations, a method for optimal placement of electric terminals in a planar EMR device is proposed. (paper)

Contracting a planar graph efficiently

DEFF Research Database (Denmark)

Holm, Jacob; Italiano, Giuseppe F.; Karczmarz, Adam

2017-01-01

the data structure, we can achieve optimal running times for decremental bridge detection, 2-edge connectivity, maximal 3-edge connected components, and the problem of finding a unique perfect matching for a static planar graph. Furthermore, we improve the running times of algorithms for several planar...

Inkjet-based adaptive planarization (Conference Presentation)

Science.gov (United States)

Singhal, Shrawan; Grigas, Michelle M.; Khusnatdinov, Niyaz; Sreenivasan, Srinivasan V.

2017-03-01

Planarization is a critical unit step in the lithography process because it enables patterning of surfaces with versatile pattern density without compromising on the stringent planarity and depth-of-focus requirements. In addition to nanoscale pattern density variation, parasitics such as pre-existing wafer topography, can corrupt the desired process output after planarization. The topography of any surface can be classified in three broad categories, depending upon the amplitude and spatial wavelength of the same [1], [2]: (i) nominal shape, (ii) nanotopography and (iii) roughness. The nominal shape is given by the largest spatial wavelengths, typically back is one technique used for micron scale device manufacturing [3]. As the name implies, a glass dielectric is spin-coated on the substrate followed by etching in a chemistry that ensures equal etching rates for both the sacrificial glass and the underlying film or substrate material. Photoresists may also be used instead of glass. However, the global planarity that can be achieved by this technique is limited. Also, planarization over a large isolated topographical feature has been studied for the reverse-tone Jet-and-Flash Imprint Lithography process, also known as JFIL-R [4]. This relies on surface tension and capillary effects to smoothen a spin-coated Si containing film that can be etched to obtain a smooth profile. To meet the stringent requirement of planarity in submicron device technologies Chemical Mechanical Planarization (CMP) is the most widely used planarization technology [5], [6]. It uses a combination of abrasive laden chemical slurry and a mechanical pad for achieving planar profiles. The biggest concern with CMP is the dependence of material removal rate on the pattern density of material, leading to the formation of a step between the high density and low-density. The step shows up as a long-range thickness variation in the planarized film, similar in scale to pre-existing substrate topography

9 CFR 3.113 - Primary enclosures used to transport marine mammals.

Science.gov (United States)

2010-01-01

... marine mammals. 3.113 Section 3.113 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION... the animals, their handlers, or other persons. (d) Marine mammals transported in the same primary... used. Within the primary enclosures used to transport marine mammals, the animals will be maintained on...

Interactive object modelling based on piecewise planar surface patches.

Science.gov (United States)

Prankl, Johann; Zillich, Michael; Vincze, Markus

2013-06-01

Detecting elements such as planes in 3D is essential to describe objects for applications such as robotics and augmented reality. While plane estimation is well studied, table-top scenes exhibit a large number of planes and methods often lock onto a dominant plane or do not estimate 3D object structure but only homographies of individual planes. In this paper we introduce MDL to the problem of incrementally detecting multiple planar patches in a scene using tracked interest points in image sequences. Planar patches are reconstructed and stored in a keyframe-based graph structure. In case different motions occur, separate object hypotheses are modelled from currently visible patches and patches seen in previous frames. We evaluate our approach on a standard data set published by the Visual Geometry Group at the University of Oxford [24] and on our own data set containing table-top scenes. Results indicate that our approach significantly improves over the state-of-the-art algorithms.

Interactive object modelling based on piecewise planar surface patches☆

Science.gov (United States)

Prankl, Johann; Zillich, Michael; Vincze, Markus

2013-01-01

Detecting elements such as planes in 3D is essential to describe objects for applications such as robotics and augmented reality. While plane estimation is well studied, table-top scenes exhibit a large number of planes and methods often lock onto a dominant plane or do not estimate 3D object structure but only homographies of individual planes. In this paper we introduce MDL to the problem of incrementally detecting multiple planar patches in a scene using tracked interest points in image sequences. Planar patches are reconstructed and stored in a keyframe-based graph structure. In case different motions occur, separate object hypotheses are modelled from currently visible patches and patches seen in previous frames. We evaluate our approach on a standard data set published by the Visual Geometry Group at the University of Oxford [24] and on our own data set containing table-top scenes. Results indicate that our approach significantly improves over the state-of-the-art algorithms. PMID:24511219

Measured surface magnetic field attenuation of shielded windows and wire mesh over an electrically small enclosure

International Nuclear Information System (INIS)

Hoeft, L.O.; Hofstra, J.S.; Karaskiewicz, R.J.; Wiser, G.

1984-01-01

The surface magnetic field attenuation of five types of shielded transparency (window) material was measured over the frequency range 10 kHz to 100 MHz by installing them on an .61 m x .61 m x .2 m enclosure, placing the enclosure on the wall of a TEM cell and measuring the surface and interior magnetic fields using a computer-controlled network analyzer system. The samples included two thicknesses of conductive grids on acrylic, hardware, cloth with 1/8 and 1/4-inch mesh, and a fine mesh laminated optical display window. These measurements are indicative of an enclosure with aperture coupling; namely, they become frequency-independent at high frequencies. Coarse mesh samples (1/8-1/4-inch mesh) were able to provide 50 to 60 dB of magnetic field reduction at tens of MHz, whereas the finer mesh did slightly better. This behavior is consistent with magnetic polarizability theory. Material thickness did not have an appreciable effect for frequencies above a MHz

Sound absorption effects in a rectangular enclosure with the foamed aluminum sheet absorber

International Nuclear Information System (INIS)

Oh, Jae Eung; Chung, Jin Tai; Kim, Sang Hun; Chung, Kyung Ryul

1998-01-01

For the purpose of finding out the optimal thickness of sound absorber and the sound absorption effects due to the selected thickness at an interested frequency range, the analytical study identifies the interior and exterior sound field characteristics of a rectangular enclosure with foamed aluminum lining and the experimental verification is performed with random noise input. By using a two-microphone impedance tube, we measure experimentally the absorption coefficient and the impedance of simple sound absorbing materials. Measured acoustical parameters of the test samples are applied to the theoretical analysis to predict sound pressure field in the cavity. The sound absorption effects from measurements are compared to predicted ones in both cases with and without foamed aluminum lining in the cavity of the rectangular enclosure

Contrasting effects of nitrogenous pollution on fitness and swimming performance of Iberian waterfrog, Pelophylax perezi (Seoane, 1885), larvae in mesocosms and field enclosures.

Science.gov (United States)

Egea-Serrano, A; Tejedo, M

2014-01-01

Amphibians are declining worldwide and pollutants have been implicated as a major contributor to these declines. To understand these declines, many studies have assessed the impact of pollutants on amphibian behaviour. However, information regarding their effect on locomotor abilities, as well as the intra-specific variation of the tolerance to pollutants, is extremely rare. Further, the majority of studies examining the impact of pollutants on amphibians have been conducted in simplified laboratory settings. Given the complexity of natural systems, determining whether amphibian responses in laboratory studies can be generalized to more realistic natural scenarios is critical. Towards this goal, this study assessed the impact of nitrogenous pollution on survival and fitness-related larval traits (growth, mass and swimming performance) for three populations of the frog Pelophylax perezi, exposed to different degrees of eutrophication in two different and complementary experiments: (1) pond mesocosms, with NH4Cl isolated or combined with NaNO2 and NaNO3, and (2) field enclosures placed in natural streams differing in their degree of pollution. For both mesocosm and field enclosure experiments, larval mortality was unaffected by nitrogenous pollution. However, in the mesocosm experiment, exposure to nitrogenous compounds reduced final larvae mass and growth. In contrast, in the enclosure experiment, polluted locations facilitated final mass and growth of surviving tadpoles. Population-level variation in the effect of pollution was observed for final larval mass in the mesocosm but not in the field enclosure experiment. In addition, although nitrogenous compounds in both mesocosm and natural conditions had no direct effect on absolute larval swimming performance, they may impact the viability of larvae by affecting the relationships between growth and the swimming abilities. The differential pattern found in the impacts of nitrogenous compounds on larvae of P. perezi

Interactions between piscivores, zooplanktivores and zooplankton in submerged macrophytes : Preliminary observations from enclosure and pond experiments

DEFF Research Database (Denmark)

Jacobsen, Lene; Perrow, M.R.; Landkildehus, F.

1997-01-01

behavioural changes of zooplanktivores has received little attention, even though this may be an important mechanism in enhancing the stability of submerged macrophytes in shallow lakes. Preliminary observations from an unreplicated large-scale field enclosure experiment and a replicated pond experiment...... and the presence of zooplanktivores typically changed the habitat selection of cladoceran zooplankton. In the case of piscivore/zooplanktivore interactions, the risk of predation was enough to generate clear responses even where the losses to predation were low. However, only in the enclosure experiment...

Piecewise planar Möbius bands

DEFF Research Database (Denmark)

Gravesen, Jens

2005-01-01

t is shown that a closed polygon with an odd number of vertices is the median of exactly one piecewise planar cylinder and one piecewise planar Möbius band, intersecting each other orthogonally. A closed polygon with an even number of vertices is in the generic case neither the median...

Computing half-plane and strip discrepancy of planar point sets

NARCIS (Netherlands)

Berg, de M.

1996-01-01

We present efficient algorithms for two problems concerning the discrepancy of a set S of n points in the unit square in the plane. First, we describe an algorithm for maintaining the half-plane discrepancy of S under insertions and deletions of points. The algorithm runs in O(nlogn) worst-case time

Numerical modeling of buoyancy-driven turbulent flows in enclosures

International Nuclear Information System (INIS)

Hsieh, K.J.; Lien, F.S.

2004-01-01

Modeling turbulent natural convection in enclosures with differentially heated vertical walls is numerically challenging, in particular, when low-Reynolds-number (low-Re) models are adopted. When the turbulence level in the core region of cavity is low, most low-Re models, particular those showing good performance for bypass transitional flows, tend to relaminarize the flow and, as a consequence, significantly underpredict the near-wall turbulence intensities and boundary-layer thickness. Another challenge associated with low-turbulence buoyancy-driven flows in enclosures is its inherent unsteadiness, which can pose convergence problems when a steady Reynolds-averaged Navier-Stokes (RANS) equation is solved. In the present study, an unsteady RANS approach in conjunction with the low-Re k-ε model of Lien and Leschziner [Int. J. Comput. Fluid Dyn. 12 (1999) 1] is initially adopted and the predicted flow field is found effectively relaminarized. To overcome this difficulty, likely caused by the low-Re functions in the ε-equation, the two-layer approach is attempted, in which ε is prescribed algebraically using the one-equation k-l model of Wolfshtein [Int. J. Heat Mass Transfer 12 (1969) 301]. The two-layer approach combined with a quadratic stress-strain relation gives overall the best performance in terms of mean velocities, temperature and turbulence quantities

Moisture ingress into electronics enclosures under isothermal conditions

DEFF Research Database (Denmark)

Staliulionis, Zygimantas; Jabbaribehnam, Mirmasoud; Hattel, Jesper Henri

2016-01-01

loads are still not understood well by design engineers, therefore this field has become one of the bottlenecks in the electronics system design. The objective of this paper is to model moisture ingress into an electronics enclosure under isothermal conditions. The moisture diffusion model is based......The number of electronics used in outdoor environment is constantly growing. The humidity causes about 19 % of all electronics failures and, especially, moisture increases these problems due to the ongoing process of miniaturization and lower power consumption of electronic components. Moisture...

Planar impact experiments for EOS measurements

International Nuclear Information System (INIS)

Furnish, M.D.

1993-01-01

The community concerned with the numerical modeling of groundshock produced by underground nuclear tests must have access to materials data to benchmark models of rock behavior. Historically the primary source of these data has been planar impact experiments. These experiments have involved gun, explosive and electrical launchers. Other methods of introducing planar shocks include shock driving by in-contact explosives or laser bursts. This paper briefly describes gun launcher-based planar impact methods used to characterize geological materials at Sandia National Laboratories

9 CFR 112.2 - Final container label, carton label, and enclosure.

Science.gov (United States)

2010-01-01

... carton; (10) In the case of a product which contains an antibiotic added during the production process... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Final container label, carton label, and enclosure. 112.2 Section 112.2 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION...

9 CFR 3.87 - Primary enclosures used to transport nonhuman primates.

Science.gov (United States)

2010-01-01

... nonhuman primates. 3.87 Section 3.87 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE..., and Transportation of Nonhuman Primates 2 Transportation Standards § 3.87 Primary enclosures used to transport nonhuman primates. Any person subject to the Animal Welfare regulations (9 CFR parts 1, 2, and 3...

Use of the geometric mean of opposing planar projections in pre-reconstruction restoration of SPECT images

International Nuclear Information System (INIS)

Boulfelfel, D.; Rangayyan, R.M.; Hahn, L.J.; Kloiber, R.

1992-01-01

This paper presents a restoration scheme for single photon emission computed tomography (SPECT) images that performs restoration before reconstruction (pre-reconstruction restoration) from planar (projection) images. In this scheme, the pixel-by-pixel geometric mean of each pair of opposing (conjugate) planar projections is computed prior to the reconstruction process. The averaging process is shown to help in making the degradation phenomenon less dependent on the distance of each point of the object from the camera. The restoration filters investigated are the Wiener and power spectrum equalization filters. (author)

Numerical Investigation of the Effect of Magnetic Field on Natural Convection in a Curved-Shape Enclosure

Directory of Open Access Journals (Sweden)

M. Sheikholeslami

2013-01-01

Full Text Available This investigation reports the magnetic field effect on natural convection heat transfer in a curved-shape enclosure. The numerical investigation is carried out using the control volume-based-finite element method (CVFEM. The numerical investigations are performed for various values of Hartmann number and Rayleigh number. The obtained results are depicted in terms of streamlines and isotherms which show the significant effects of Hartmann number on the fluid flow and temperature distribution inside the enclosure. Also, it was found that the Nusselt number decreases with an increase in the Hartmann number.

Mathematical modelling of coupled heat and mass transport into an electronic enclosure

DEFF Research Database (Denmark)

Staliulionis, Zygimantas; Jabbaribehnam, Mirmasoud; Hattel, Jesper Henri

2016-01-01

In contrast to high fidelity CFD codes which require higher computational effort/time, the well-known Resistor-Capacitor (RC) approach requires much lower calculation time, but also with a lower resolution of the geometrical arrangement. Therefore, for enclosures without too complex geometry...

Surveillance and Maintenance Plan for the 105-C Reactor Safe Storage Enclosure

International Nuclear Information System (INIS)

Logan, T. E.

1998-01-01

This document provides a plan for implementing surveillance and maintenance activities to ensure that the 105-C Reactor Safe Storage Enclosure is maintained in a safe, environmentally secure, and cost-effective manner until subsequent closure during the final disposition phase of decommissioning

Contact planarization of ensemble nanowires

Science.gov (United States)

Chia, A. C. E.; LaPierre, R. R.

2011-06-01

The viability of four organic polymers (S1808, SC200, SU8 and Cyclotene) as filling materials to achieve planarization of ensemble nanowire arrays is reported. Analysis of the porosity, surface roughness and thermal stability of each filling material was performed. Sonication was used as an effective method to remove the tops of the nanowires (NWs) to achieve complete planarization. Ensemble nanowire devices were fully fabricated and I-V measurements confirmed that Cyclotene effectively planarizes the NWs while still serving the role as an insulating layer between the top and bottom contacts. These processes and analysis can be easily implemented into future characterization and fabrication of ensemble NWs for optoelectronic device applications.

Quality control on planar n-in-n pixel sensors — Recent progress of ATLAS planar pixel sensors

International Nuclear Information System (INIS)

Klingenberg, R.

2013-01-01

To extend the physics reach of the Large Hadron Collider (LHC), upgrades to the accelerator are planned which will increase the peak luminosity by a factor 5–10. To cope with the increased occupancy and radiation damage, the ATLAS experiment plans to introduce an all-silicon inner tracker with the high luminosity upgrade (HL-LHC). To investigate the suitability of pixel sensors using the proven planar technology for the upgraded tracker, the ATLAS Upgrade Planar Pixel Sensor (PPS) R and D Project was established. Main areas of research are the performance of planar pixel sensors at highest fluences, the exploration of possibilities for cost reduction to enable the instrumentation of large areas, the achievement of slim or active edges to provide low geometric inefficiencies without the need for shingling of modules and the investigation of the operation of highly irradiated sensors at low thresholds to increase the efficiency. The Insertable b-layer (IBL) is the first upgrade project within the ATLAS experiment and will employ a new detector layer consisting of silicon pixel sensors, which were improved and prototyped in the framework of the planar pixel sensor R and D project. A special focus of this paper is the status of the development and testing of planar n-in-n pixel sensors including the quality control of the on-going series production and postprocessing of sensor wafers. A high yield of produced planar sensor wafers and FE-I4 double chip sensors after first steps of post-processing including under bump metallization and dicing is observed. -- Highlights: ► Prototypes of irradiated planar n-in-n sensors have been successfully tested under laboratory conditions. ► A quality assurance programme on the series production of planar sensors for the IBL has started. ► A high yield of double chip sensors during the series production is observed which are compatible to the specifications to this detector component.

A measure of variable planar locations anchored on the centroid of the vowel space

DEFF Research Database (Denmark)

Watt, Dominic; Fabricius, Anne

2011-01-01

as an anchor point or vertex for calculation of planar locations on formant plots, permitting quantification of the distribution of vowel tokens within the space. This information, along with details such as Euclidean distances, can then be used to precisely pinpoint the trajectories of diachronic change...

MHD mixed convection flow and heat transfer in an open C-shaped enclosure using water-copper oxide nanofluid

Science.gov (United States)

Armaghani, T.; Esmaeili, H.; Mohammadpoor, Y. A.; Pop, I.

2018-01-01

In this paper, the steady mixed convection flow and heat transfer of water-copper oxide nanofluid in an open C-shaped enclosure is investigated numerically. The enclosure is under constant magnetic field. Effects of Richardson number, magnetic and nanofluid volume fraction parameters are studied and discussed. The nanofluid with a cold temperature of T C and a velocity of u c enters the enclosure from the top right corner and exits from the bottom right corner. The vertical wall of the left side is subjected to a hot and constant temperature T h . Also, other walls are insulated. It is found that the heat transfer is increased via increasing the Hartmann and Reynolds numbers. For low Reynolds numbers, the enhances of the Hartman number leads to a slightly increases of the average Nusselt number, but for high Reynolds numbers, the average Nusselt number gets an ascending trend and the increase in the Hartmann number shows its effect more pronounced. Also, with increase in Ri, the effect of nanofluid on the heat transfer increases. Due to practical impotence, the study of mixed convection heat transfer in enclosures and various shaped of cavities has attracted remarkable attentions in the past few decades. Significant applications of the mixed convection flow can be found in atmospheric flows, solar energy storage, heat exchangers, lubrication technology, drying technologies, cooling of the electronic devices, etc. The present results are original and new for the problem of MHD mixed convection flow and heat transfer in an open C-shaped enclosure using water-copper oxide nanofluid. Comparison of the obtained results with those from the open literature (Mahmoodi et al. [24]) is acceptable.

Innovative enclosure dome/observing aperture system design for the MROI Array Telescopes

Science.gov (United States)

Busatta, A.; Marchiori, G.; Mian, S.; Payne, I.; Pozzobon, M.

2010-07-01

The close-pack array of the MROI necessitated an original design for the Unit Telescope Enclosure (UTE) at Magdalena Ridge Observatory. The Magdalena Ridge Observatory Interferometer (MROI) is a project which comprises an array of up to ten (10) 1.4m diameter mirror telescopes arranged in a "Y" configuration. Each of these telescopes will be housed inside a Unit Telescope Enclosure (UTE) which are relocatable onto any of 28 stations. The most compact configuration includes all ten telescopes, several of which are at a relative distance of less than 8m center to center from each other. Since the minimum angle of the field of regard is 30° with respect to the horizon, it is difficult to prevent optical blockage caused by adjacent UTEs in this compact array. This paper presents the design constraints inherent in meeting the requirement for the close-pack array. An innovative design enclosure was created which incorporates an unique dome/observing aperture system. The description of this system focuses on how the field of regard requirement led to an unique and highly innovative concept that had to be able to operate in the harsh environmental conditions encountered at an altitude of 10,460ft (3,188m). Finally, we describe the wide use of composites materials and structures (e.g. glass/carbon fibres, sandwich panels etc.) on the aperture system which represents the only way to guarantee adequate thermal and environmental protection, compactness, structural stability and limited power consumption due to reduced mass.

A numerical study on buoyancy-driven flow in an inclined square enclosure heated and cooled on adjacent walls

International Nuclear Information System (INIS)

Aydin, O.; Uenal, A.; Ayhan, T.

1999-01-01

Buoyancy-driven flows in enclosures play a vital role in many engineering applications such as double glazing, ventilation of rooms, nuclear reactor insulation, solar energy collection, cooling of electronic components, and crystal growth in liquids. Here, numerical study on buoyancy-driven laminar flow in an inclined square enclosure heated from one side and cooled from the adjacent side is conducted using finite difference methods. The effect of inclination angle on fluid flow and heat transfer is investigated by varying the angle of inclination between 0 degree and 360degree, and the results are presented in the form of streamlines and isotherms for different inclination angles and Rayleigh numbers. On the basis of the numerical data, the authors determine the critical values of the inclination angle at which the rate of the transfer within the enclosure is either maximum or minimum

Improvements of the two-dimensional FDTD method for the simulation of normal- and superconducting planar waveguides using time series analysis

International Nuclear Information System (INIS)

Hofschen, S.; Wolff, I.

1996-01-01

Time-domain simulation results of two-dimensional (2-D) planar waveguide finite-difference time-domain (FDTD) analysis are normally analyzed using Fourier transform. The introduced method of time series analysis to extract propagation and attenuation constants reduces the desired computation time drastically. Additionally, a nonequidistant discretization together with an adequate excitation technique is used to reduce the number of spatial grid points. Therefore, it is possible to reduce the number of spatial grid points. Therefore, it is possible to simulate normal- and superconducting planar waveguide structures with very thin conductors and small dimensions, as they are used in MMIC technology. The simulation results are compared with measurements and show good agreement

Improvements of the two-dimensional FDTD method for the simulation of normal- and superconducting planar waveguides using time series analysis

Energy Technology Data Exchange (ETDEWEB)

Hofschen, S.; Wolff, I. [Gerhard Mercator Univ. of Duisburg (Germany). Dept. of Electrical Engineering

1996-08-01

Time-domain simulation results of two-dimensional (2-D) planar waveguide finite-difference time-domain (FDTD) analysis are normally analyzed using Fourier transform. The introduced method of time series analysis to extract propagation and attenuation constants reduces the desired computation time drastically. Additionally, a nonequidistant discretization together with an adequate excitation technique is used to reduce the number of spatial grid points. Therefore, it is possible to reduce the number of spatial grid points. Therefore, it is possible to simulate normal- and superconducting planar waveguide structures with very thin conductors and small dimensions, as they are used in MMIC technology. The simulation results are compared with measurements and show good agreement.

Thermosolutal convection in saturated porous enclosure with concentrated energy and solute sources

Energy Technology Data Exchange (ETDEWEB)

Liu, Di; Zhao, Fu-Yun; Tang, Guang-Fa [College of Civil Engineering, Hunan University, Changsha (China)

2008-01-15

Double diffusive natural convection within a vertical porous enclosure with localized heating and salting from one side is numerically studied by the finite element based finite volume method. In the formulation of the problem, use is made of the Darcy model, which allows the slip boundary condition on a solid wall to be satisfied. Comparisons with benchmark solutions for natural convection in fluid saturated porous enclosures are first presented to validate the code. Following that, an extensive series of numerical simulations is conducted in the range of -55 {<=} N {<=} + 55 and 0.125 {<=} L {<=} 0.875, where N and L are the buoyancy ratio and the element location, respectively. Streamlines, heatlines, masslines, isotherms and iso-concentrations in the system are produced to illustrate the flow structure transition from solutal dominated opposing to thermal dominated and solutal dominated aiding flows, respectively. The computed average Nusselt and Sherwood numbers provide guidance for locating the heating and salting element. (author)

Thermosolutal convection in saturated porous enclosure with concentrated energy and solute sources

Energy Technology Data Exchange (ETDEWEB)

Liu Di [College of Civil Engineering, Hunan University, Changsha (China)], E-mail: liudi66@163.com; Zhao Fuyun [College of Civil Engineering, Hunan University, Changsha (China)], E-mail: zfycfdnet@163.com; Tang Guangfa [College of Civil Engineering, Hunan University, Changsha (China)], E-mail: gftangcfd@163.com

2008-01-15

Double diffusive natural convection within a vertical porous enclosure with localized heating and salting from one side is numerically studied by the finite element based finite volume method. In the formulation of the problem, use is made of the Darcy model, which allows the slip boundary condition on a solid wall to be satisfied. Comparisons with benchmark solutions for natural convection in fluid saturated porous enclosures are first presented to validate the code. Following that, an extensive series of numerical simulations is conducted in the range of -55 {<=} N {<=} + 55 and 0.125 {<=} L {<=} 0.875, where N and L are the buoyancy ratio and the element location, respectively. Streamlines, heatlines, masslines, isotherms and iso-concentrations in the system are produced to illustrate the flow structure transition from solutal dominated opposing to thermal dominated and solutal dominated aiding flows, respectively. The computed average Nusselt and Sherwood numbers provide guidance for locating the heating and salting element.

Electromagnetic interference reduction using electromagnetic bandgap structures in packages, enclosures, cavities, and antennas

Science.gov (United States)

Mohajer Iravani, Baharak

Electromagnetic interference (EMI) is a source of noise problems in electronic devices. The EMI is attributed to coupling between sources of radiation and components placed in the same media such as package or chassis. This coupling can be either through conducting currents or through radiation. The radiation of electromagnetic (EM) fields is supported by surface currents. Thus, minimizing these surface currents is considered a major and critical step to suppress EMI. In this work, we present novel strategies to confine surface currents in different applications including packages, enclosures, cavities, and antennas. The efficiency of present methods of EM noise suppression is limited due to different drawbacks. For example, the traditional use of lossy materials and absorbers suffers from considerable disadvantages including mechanical and thermal reliability leading to limited life time, cost, volume, and weight. In this work, we consider the use of Electromagnetic Band Gap (EBG) structures. These structures are suitable for suppressing surface currents within a frequency band denoted as the bandgap. Their design is straight forward, they are inexpensive to implement, and they do not suffer from the limitations of the previous methods. A new method of EM noise suppression in enclosures and cavity-backed antennas using mushroom-type EBG structures is introduced. The effectiveness of the EBG as an EMI suppresser is demonstrated using numerical simulations and experimental measurements. To allow integration of EBGs in printed circuit boards and packages, novel miniaturized simple planar EBG structures based on use of high-k dielectric material (epsilonr > 100) are proposed. The design consists of meander lines and patches. The inductive meander lines serve to provide current continuity bridges between the capacitive patches. The high-k dielectric material increases the effective capacitive load substantially in comparison to commonly used material with much lower

Orientifold Planar Equivalence: The Chiral Condensate

DEFF Research Database (Denmark)

Armoni, Adi; Lucini, Biagio; Patella, Agostino

2008-01-01

The recently introduced orientifold planar equivalence is a promising tool for solving non-perturbative problems in QCD. One of the predictions of orientifold planar equivalence is that the chiral condensates of a theory with $N_f$ flavours of Dirac fermions in the symmetric (or antisymmetric...

Overview of Planar Magnetic Technology — Fundamental Properties

DEFF Research Database (Denmark)

Ouyang, Ziwei; Andersen, Michael A. E.

2014-01-01

The momentum towards high efficiency, high frequency, and high power density in power supplies limits wide use of conventional wire-wound magnetic components. This article gives an overview of planar magnetic technologies with respect to the development of modern power electronics. The major...... advantages and disadvantages in the use of planar magnetics for high frequency power converters are covered, and publications on planar magnetics are reviewed. A detailed survey of winding conduction loss, leakage inductance and winding capacitance for planar magnetics is presented so power electronics...

An Explicit Enclosure of the Solution Set of Overdetermined Interval Linear Equations

Czech Academy of Sciences Publication Activity Database

Rohn, Jiří

2017-01-01

Roč. 24, February (2017), s. 1-10 ISSN 1573-1340 Institutional support: RVO:67985807 Keywords : interval linear equations * interval hull * unit midpoint * enclosure Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics http://interval.louisiana.edu/ reliable -computing-journal/volume-24/ reliable -computing-24-pp-001-010.pdf

Viscous dissipation and radiation effects on MHD natural convection in a square enclosure filled with a porous medium

Energy Technology Data Exchange (ETDEWEB)

Ahmed, Sameh E., E-mail: sameh_sci_math@yahoo.com [Department of Mathematics, Faculty of Sciences, South Valley University, Qena (Egypt); Hussein, Ahmed Kadhim, E-mail: ahmedkadhim7474@gmail.com [College of Engineering, Mechanical Engineering Department, Babylon University, Babylon City—Hilla (Iraq); Mohammed, H.A. [Department of Thermofluids, Faculty of Mechanical Engineering, University Teknologi Malaysia (UTM), 81310 UTM Skudai, Johor Bahru (Malaysia); Adegun, I.K. [Department of Mechanical Engineering, University of Ilorin, Ilorin (Nigeria); Zhang, Xiaohui [School of Physics Science and Technology, School of Energy—Soochow University, Suzhou 215006, Jiangsu (China); Kolsi, Lioua [Unite de Metrologie en Mecanique des Fluides et Thermique, Ecole Nationale d’Ingenieurs, Monastir (Tunisia); Hasanpour, Arman [Department of Mechanical Engineering, Babol University of Technology, PO Box 484, Babol (Iran, Islamic Republic of); Sivasankaran, S. [Institute of Mathematical Sciences, University of Malaya, Kuala Lumpur 50603 (Malaysia)

2014-01-15

Highlights: • Ha decelerates the flow field. • Ha enhances conduction. • Magnetic field orientation is important. • Radiation parameter important. • Nu decreases as Ha increases. -- Abstract: Numerical two-dimensional analysis using finite difference approach with “line method” is performed on the laminar magneto-hydrodynamic natural convection in a square enclosure filled with a porous medium to investigate the effects of viscous dissipation and radiation. The enclosure heated from left vertical sidewall and cooled from an opposing right vertical sidewall. The top and bottom walls of the enclosure are considered adiabatic. The flow in the square enclosure is subjected to a uniform magnetic field at various orientation angles (φ = 0°, 30°, 45°, 60° and 90°). Numerical computations occur at wide ranges of Rayleigh number, viscous dissipation parameter, magnetic field orientation angles, Hartmann number and radiation parameter. Numerical results are presented with the aid of tables and graphical illustrations. The results of the present work explain that the local and average Nusselt numbers at the hot and cold sidewalls increase with increasing the radiation parameter. From the other side, the role of viscous dissipation parameter is to reduce the local and average Nusselt numbers at the hot left wall, while it improves them at the cold right wall. The results are compared with another published results and it found to be in a good agreement.

Phase Mixing of Alfvén Waves Near a 2D Magnetic Null Point J. A. ...

Indian Academy of Sciences (India)

nar Alfvén wavefront remains planar, despite the varying equilibrium ..... Since the wave is so stretched where it forms the 'reflection point' in the wave- .... Thus, we find that the Alfvén wave is again distorted from its initially planar shape,.

Planar simplification and texturing of dense point cloud maps

NARCIS (Netherlands)

Ma, L.; Whelan, T.; Bondarau, Y.; With, de P.H.N.; McDonald, J.

2013-01-01

Dense RGB-D based SLAM techniques and highfidelity LIDAR scanners are examples from an abundant set of systems capable of providing multi-million point datasets. These large datasets quickly become difficult to process and work with due to the sheer volume of data, which typically contains

Flux-redistribution in the focal region of a planar Fresnel ring mirror

Energy Technology Data Exchange (ETDEWEB)

Sastroamidjojo, M.S.A. (Gadjah Mada Univ., Indonesia); Lubis, W.

1979-01-01

The results of an investigation of flux redistribution at the focal region of a planar Fresnel ring mirror are reported. A parabolic mirror of large aperture was used to provide a parallel beam of light which was directed at the Fresnel test object. A cotton thread grid was used as a mapping aid to provide a 25 x 25 matrix of spatial data points. (SPH)

Some remarks on non-planar Feynman diagrams

International Nuclear Information System (INIS)

Bielas, Krzysztof; Dubovyk, Ievgen; Gluza, Janusz

2013-12-01

Two criteria for planarity of a Feynman diagram upon its propagators (momentum ows) are presented. Instructive Mathematica programs that solve the problem and examples are provided. A simple geometric argument is used to show that while one can planarize non-planar graphs by embedding them on higher-genus surfaces (in the example it is a torus), there is still a problem with defining appropriate dual variables since the corresponding faces of the graph are absorbed by torus generators.

Some remarks on non-planar Feynman diagrams

Energy Technology Data Exchange (ETDEWEB)

Bielas, Krzysztof; Dubovyk, Ievgen; Gluza, Janusz [Silesia Univ., Katowice (Poland). Inst. of Physics; Riemann, Tord [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

2013-12-15

Two criteria for planarity of a Feynman diagram upon its propagators (momentum ows) are presented. Instructive Mathematica programs that solve the problem and examples are provided. A simple geometric argument is used to show that while one can planarize non-planar graphs by embedding them on higher-genus surfaces (in the example it is a torus), there is still a problem with defining appropriate dual variables since the corresponding faces of the graph are absorbed by torus generators.

CFD simulation and statistical analysis of moisture transfer into an electronic enclosure

DEFF Research Database (Denmark)

Shojaee Nasirabadi, Parizad; Jabbaribehnam, Mirmasoud; Hattel, Jesper Henri

2017-01-01

CFD model for the isothermal case. The model is then combined with a two level factorial design to identify the significant factors as well as the potential interactions us- ing the numerical simulation results. In the second part of this study, a non-isothermal case is studied, in which the enclosure...

Ratios of colony mass to thermal conductance of tree and man-made nest enclosures of Apis mellifera: implications for survival, clustering, humidity regulation and Varroa destructor

Science.gov (United States)

Mitchell, Derek

2016-05-01

In the absence of human intervention, the honeybee ( Apis mellifera L.) usually constructs its nest in a tree within a tall, narrow, thick-walled cavity high above the ground (the enclosure); however, most research and apiculture is conducted in the thin-walled, squat wooden enclosures we know as hives. This experimental research, using various hives and thermal models of trees, has found that the heat transfer rate is approximately four to seven times greater in the hives in common use, compared to a typical tree enclosure in winter configuration. This gives a ratio of colony mass to lumped enclosure thermal conductance (MCR) of less than 0.8 kgW-1 K for wooden hives and greater than 5 kgW-1 K for tree enclosures. This result for tree enclosures implies higher levels of humidity in the nest, increased survival of smaller colonies and lower Varroa destructor breeding success. Many honeybee behaviours previously thought to be intrinsic may only be a coping mechanism for human intervention; for example, at an MCR of above 2 kgW-1 K, clustering in a tree enclosure may be an optional, rare, heat conservation behaviour for established colonies, rather than the compulsory, frequent, life-saving behaviour that is in the hives in common use. The implied improved survival in hives with thermal properties of tree nests may help to solve some of the problems honeybees are currently facing in apiculture.

End points of planar reaching movements are disrupted by small force pulses: an evaluation of the hypothesis of equifinality.

Science.gov (United States)

Popescu, F C; Rymer, W Z

2000-11-01

A single force pulse was applied unexpectedly to the arms of five normal human subjects during nonvisually guided planar reaching movements of 10-cm amplitude. The pulse was applied by a powered manipulandum in a direction perpendicular to the motion of the hand, which gripped the manipulandum via a handle at the beginning, at the middle, or toward the end the movement. It was small and brief (10 N, 10 ms), so that it was barely perceptible. We found that the end points of the perturbed motions were systematically different from those of the unperturbed movements. This difference, dubbed "terminal error," averaged 14.4 +/- 9.8% (mean +/- SD) of the movement distance. The terminal error was not necessarily in the direction of the perturbation, although it was affected by it, and it did not decrease significantly with practice. For example, while perturbations involving elbow extension resulted in a statistically significant shift in mean end-point and target-acquisition frequency, the flexion perturbations were not clearly affected. We argue that this error distribution is inconsistent with the "equilibrium point hypothesis" (EPH), which predicts minimal terminal error is determined primarily by the variance in the command signal itself, a property referred to as "equifinality." This property reputedly derives from the "spring-like" properties of muscle and is enhanced by reflexes. To ensure that terminal errors were not due to mid-course voluntary corrections, we only accepted trials in which the final position was already established before such a voluntary response to the perturbation could have begun, that is, in a time interval shorter than the minimum reaction time (RT) for that subject. This RT was estimated for each subject in supplementary experiments in which the subject was instructed to move to a new target if perturbed and to the old target if no perturbation was detected. These RT movements were found to either stop or slow greatly at the original

Planarity certification of ATLAS Micromegas detector panels

Energy Technology Data Exchange (ETDEWEB)

Mueller, Ralph; Biebel, Otmar; Bortfeldt, Jonathan; Flierl, Bernhard; Hertenberger, Ralf; Loesel, Philipp; Herrmann, Maximilian [LMU Muenchen (Germany); Zibell, Andre [JMU Wuerzburg (Germany)

2016-07-01

During the second long LHC shutdown, 2019/20, the precision tracking detectors of the ATLAS muon spectrometer in the inner end caps will be replaced using Micromegas, a planar gas-detector technology. Modules of 2 m{sup 2} area are built in quadruplets from five precisely planar sandwich panels that define the anodes and the cathodes of the four active detector planes. A panel is composed of three consecutive layers FR4 - aluminum honeycomb - FR4. Single plane spatial particle resolution below 100 μm is achievable when the deviations from planarity of the strip-anodes do not exceed 80 μm RMS over the whole active area and the parallelism of the readout strips is within 30 μm. In order to measure the dimensional accuracy of each panel, laser distance sensors combined with a coordinate measurement system have been investigated. The sensor requirements to measure the planarity of the panels are a resolution of 0.3 μm and a beam spot diameter of ∼20 μm, well below 100 μ m the size of the smallest structures. We report on achieved planarities of the panels and the performance of the laser sensor system. A panel with an RMS better than 30 μm was build and the evolution of its planarity due to humidity and temperature effects is shown.

Electrical alignment of antenna coordinate system in a planar near-field setup

DEFF Research Database (Denmark)

Mynster, Anders P.; Nielsen, Jeppe Majlund; Pivnenko, Sergey

2011-01-01

In this paper, a simple and efficient electrical alignment procedure known as flip-test is adapted and applied to check and correct two errors in the mechanical setup of a planar near-field system: the mis-pointing of the z-axis of the antenna coordinate system with respect to the scan plane...... and the displacement of the center point of the scan plane with respect to the z-axis of the antenna coordinate system. Simulations of the errors and their correction algorithms were carried out with different models of antennas composed of Hertzian dipoles and an optimum algorithm was then selected. The proposed...

Hydrogen–Hydrogen Bonding in Planar Biphenyl, Predicted by Atoms-In-Molecules Theory, Does Not Exist

NARCIS (Netherlands)

Poater, J; Sola, M.; Bickelhaupt, F.M.

2006-01-01

Based on an Atoms-in-Molecules (AIM) analysis, Matta et al. (Chem. Eur. J.2003, 9, 1940) recently claimed evidence for the existence of hydrogen–hydrogen bonding between ortho-hydrogen atoms, pointing towards each other from adjacent phenyl groups in planar biphenyl. This AIM result is opposed to

Feed gas contaminant control in ion transport membrane systems

Science.gov (United States)

Carolan, Michael Francis [Allentown, PA; Minford, Eric [Laurys Station, PA; Waldron, William Emil [Whitehall, PA

2009-07-07

Ion transport membrane oxidation system comprising an enclosure having an interior and an interior surface, inlet piping having an internal surface and adapted to introduce a heated feed gas into the interior of the enclosure, and outlet piping adapted to withdraw a product gas from the interior of the enclosure; one or more planar ion transport membrane modules disposed in the interior of the enclosure, each membrane module comprising mixed metal oxide material; and a preheater adapted to heat a feed gas to provide the heated feed gas to the inlet piping, wherein the preheater comprises an interior surface. Any of the interior surfaces of the enclosure, the inlet piping, and the preheater may be lined with a copper-containing metal lining. Alternatively, any of the interior surfaces of the inlet piping and the preheater may be lined with a copper-containing metal lining and the enclosure may comprise copper.

PolyFit: Polygonal Surface Reconstruction from Point Clouds

KAUST Repository

Nan, Liangliang; Wonka, Peter

2017-01-01

We propose a novel framework for reconstructing lightweight polygonal surfaces from point clouds. Unlike traditional methods that focus on either extracting good geometric primitives or obtaining proper arrangements of primitives, the emphasis of this work lies in intersecting the primitives (planes only) and seeking for an appropriate combination of them to obtain a manifold polygonal surface model without boundary.,We show that reconstruction from point clouds can be cast as a binary labeling problem. Our method is based on a hypothesizing and selection strategy. We first generate a reasonably large set of face candidates by intersecting the extracted planar primitives. Then an optimal subset of the candidate faces is selected through optimization. Our optimization is based on a binary linear programming formulation under hard constraints that enforce the final polygonal surface model to be manifold and watertight. Experiments on point clouds from various sources demonstrate that our method can generate lightweight polygonal surface models of arbitrary piecewise planar objects. Besides, our method is capable of recovering sharp features and is robust to noise, outliers, and missing data.

PolyFit: Polygonal Surface Reconstruction from Point Clouds

KAUST Repository

Nan, Liangliang

2017-12-25

We propose a novel framework for reconstructing lightweight polygonal surfaces from point clouds. Unlike traditional methods that focus on either extracting good geometric primitives or obtaining proper arrangements of primitives, the emphasis of this work lies in intersecting the primitives (planes only) and seeking for an appropriate combination of them to obtain a manifold polygonal surface model without boundary.,We show that reconstruction from point clouds can be cast as a binary labeling problem. Our method is based on a hypothesizing and selection strategy. We first generate a reasonably large set of face candidates by intersecting the extracted planar primitives. Then an optimal subset of the candidate faces is selected through optimization. Our optimization is based on a binary linear programming formulation under hard constraints that enforce the final polygonal surface model to be manifold and watertight. Experiments on point clouds from various sources demonstrate that our method can generate lightweight polygonal surface models of arbitrary piecewise planar objects. Besides, our method is capable of recovering sharp features and is robust to noise, outliers, and missing data.

How were Neolithic ditches filled in? Deposition study of two enclosures from Bohemia

Czech Academy of Sciences Publication Activity Database

Řídký, Jaroslav; Končelová, Markéta; Šumberová, Radka; Limburský, Petr; Květina, Petr

2014-01-01

Roč. 17, č. 4 (2014), s. 579-601 ISSN 1461-9571 R&D Projects: GA ČR(CZ) GAP405/11/1590 Institutional support: RVO:67985912 Keywords : Late Neolithic * Central Europe * circular enclosures * rondels * formation processes * deposition Subject RIV: AC - Archeology, Anthropology, Ethnology

ytterbium- & erbium-doped silica for planar waveguide lasers & amplifiers

DEFF Research Database (Denmark)

Dyndgaard, Morten Glarborg

2001-01-01

The purpose of this work was to demonstrate ytterbium doped planar components and investigate the possibilities of making erbium/ytterbium codoped planar waveguides in germano-silica glass. Furthermore, tools for modelling lasers and erbium/ytterbium doped amplifiers. The planar waveguides were...

Planar Poincare chart - A planar graphic representation of the state of light polarization

Science.gov (United States)

Tedjojuwono, Ken K.; Hunter, William W., Jr.; Ocheltree, Stewart L.

1989-01-01

The planar Poincare chart, which represents the complete planar equivalence of the Poincare sphere, is proposed. The four sets of basic lines are drawn on two separate charts for the generalization and convenience of reading the scale. The chart indicates the rotation of the principal axes of linear birefringent material. The relationships between parameters of the two charts are given as 2xi-2phi (orientation angle of the major axis-ellipticity angle) pair and 2alpha-delta (angle of amplitude ratio-phase difference angle) pair. The results are useful for designing and analyzing polarization properties of optical components with birefringent properties.

Efficacy of Pseudomonas fluorescens strain CL145A spray dried powder for controlling zebra mussels adhering to native unionid mussels within field enclosures

Science.gov (United States)

Luoma, James A.; Weber, Kerry L.; Severson, Todd J.; Mayer, Denise A.

2015-01-01

The efficacy of a commercially prepared spray dried powder (SDP) formulation of Pseudomonas fluorescens (strain CL145A) was evaluated for removing zebra mussels (Dreissena polymorpha) adhering to a population of unionid mussels in Lake Darling (Alexandria, Minnesota). Two groups of unionid mussels were used in the study. Unionid mussels were collected near the test area, weighed, photographed, individually tagged, and randomly allocated to one of nine test enclosures in equal proportions and then divided into two groups. The first group of unionid mussels (Group 1, n = 5 per test enclosure) were indiscriminately selected from each test enclosure and used to estimate the number of zebra mussels adhering to unionid mussels prior to exposure. The second group of unionid mussels (Group 2, n = 22 per test enclosure) were used to evaluate the efficacy of SDP for removal of adhering zebra mussels. Both Group 1 and Group 2 mussels were used to evaluate the effects of SDP exposure on unionid mussel survival.

Mixed convection flow of nanofluid in a square enclosure with an intruded rectangular fin

International Nuclear Information System (INIS)

Cong, Ran; Zhou, Xuanyu; De Souza Machado, Bruno; Das, Prodip K.

2016-01-01

Mixed convection flow in enclosures has been a subject of interest for many years due to their ever increasing applications in solar collectors, electronic cooling, lubrication technologies, food processing, and nuclear reactors. In comparison, little effort has been given to the problem of mixed convection in enclosures filled with nanofluids, while the addition of nanoparticles in a fluid base to alter specific material properties is considered a feasible solution for many heat transfer problems. Mixed convection of nanofluids is a challenging problem as the addition of nanoparticles changes the fluid’s thermo-physical properties as well as due to the complex interactions among inertia, viscous, and buoyancy forces. In this study, a two-dimensional steady-state numerical model has been developed to investigate mixed convection flow of nanofluids in a square enclosure with an intruded rectangular fin and to optimize the fin geometry for maximizing the heat transfer using the Constructal design. The model has been developed using ANSYS-FLUENT for various fin geometries. Flow fields, temperature fields, and heat transfer rates are examined for different values of Rayleigh and Reynolds numbers for several geometries of the fin with the aim of maximizing the heat transfer from the fin to the surrounding flow. Outcome of this study provides important insight into the heat transfer behavior of nanofluids, which will help in developing novel geometries with enhanced and controlled heat transfer for solar collectors and electronic devices.

Mixed convection flow of nanofluid in a square enclosure with an intruded rectangular fin

Energy Technology Data Exchange (ETDEWEB)

Cong, Ran; Zhou, Xuanyu; De Souza Machado, Bruno; Das, Prodip K., E-mail: prodip.das@ncl.ac.uk [School of Mechanical and Systems Engineering Newcastle University Newcastle upon Tyne, NE1 7RU United Kingdom (United Kingdom)

2016-07-12

Mixed convection flow in enclosures has been a subject of interest for many years due to their ever increasing applications in solar collectors, electronic cooling, lubrication technologies, food processing, and nuclear reactors. In comparison, little effort has been given to the problem of mixed convection in enclosures filled with nanofluids, while the addition of nanoparticles in a fluid base to alter specific material properties is considered a feasible solution for many heat transfer problems. Mixed convection of nanofluids is a challenging problem as the addition of nanoparticles changes the fluid’s thermo-physical properties as well as due to the complex interactions among inertia, viscous, and buoyancy forces. In this study, a two-dimensional steady-state numerical model has been developed to investigate mixed convection flow of nanofluids in a square enclosure with an intruded rectangular fin and to optimize the fin geometry for maximizing the heat transfer using the Constructal design. The model has been developed using ANSYS-FLUENT for various fin geometries. Flow fields, temperature fields, and heat transfer rates are examined for different values of Rayleigh and Reynolds numbers for several geometries of the fin with the aim of maximizing the heat transfer from the fin to the surrounding flow. Outcome of this study provides important insight into the heat transfer behavior of nanofluids, which will help in developing novel geometries with enhanced and controlled heat transfer for solar collectors and electronic devices.

Construction of 3.6m ARIES telescope enclosure with eccentric pier at Devasthal, Nainital

Science.gov (United States)

Bangia, Tarun

Space optimized enclosure with eccentric pier for 3.6m ARIES telescope presents construction challenges at the unique observing site of Devasthal, Nainital, India. Enclosure comprises of about 16.5m diameter and 14m high insulated steel framed cylindrical dome rotating on a 14m high stationery dome supporting structure and a 24m × 12m extension structure building for accommodating aluminizing plant and ventilation system etc. Great deal of manual and mechanical excavation was carried out at the rocky site using rock breaking and JCB machines. Foundation bolts for columns of dome supporting structure and extension structure building were grouted after alignment with total station. A 7m diameter hollow cylindrical pier isolated from other structures and 1.85m eccentric with dome center designed due to space limitation at site is being casted for mounting 150 MT mass of the largest 3.6m telescope in the country. A 7m diameter template was fabricated for 3.6m pier top. Most of enclosure components are manufactured and tested in works before assembly/erection at site. Dome drive was tested with dummy loads using VVVF drive with 6 drive and 12 idler wheel assemblies at works to simulate dome weight and smooth operation before erection at site. A 4.2m wide motorized windscreen is being manufactured with a special grade synthetic fabric to withstand wind speed up to 15m/s.

Mixed convection flow of nanofluid in a square enclosure with an intruded rectangular fin

Science.gov (United States)

Cong, Ran; Zhou, Xuanyu; De Souza Machado, Bruno; Das, Prodip K.

2016-07-01

Mixed convection flow in enclosures has been a subject of interest for many years due to their ever increasing applications in solar collectors, electronic cooling, lubrication technologies, food processing, and nuclear reactors. In comparison, little effort has been given to the problem of mixed convection in enclosures filled with nanofluids, while the addition of nanoparticles in a fluid base to alter specific material properties is considered a feasible solution for many heat transfer problems. Mixed convection of nanofluids is a challenging problem as the addition of nanoparticles changes the fluid's thermo-physical properties as well as due to the complex interactions among inertia, viscous, and buoyancy forces. In this study, a two-dimensional steady-state numerical model has been developed to investigate mixed convection flow of nanofluids in a square enclosure with an intruded rectangular fin and to optimize the fin geometry for maximizing the heat transfer using the Constructal design. The model has been developed using ANSYS-FLUENT for various fin geometries. Flow fields, temperature fields, and heat transfer rates are examined for different values of Rayleigh and Reynolds numbers for several geometries of the fin with the aim of maximizing the heat transfer from the fin to the surrounding flow. Outcome of this study provides important insight into the heat transfer behavior of nanofluids, which will help in developing novel geometries with enhanced and controlled heat transfer for solar collectors and electronic devices.

How to handle a Huygens' box inside an enclosure

DEFF Research Database (Denmark)

Sørensen, Morten; Bonev, Ivan Bonev; Franek, Ondrej

2013-01-01

It has been suggested that it is possible to replace printed circuit boards with a Huygens' box (HB) representation obtained from a near-field scan in simulation of far-fields from an apparatus. However, the surface equivalence theorem requires that the environment outside HB is the same in the n...... caused by violating the surface equivalence theorem can be lower than 2 dB. It is also demonstrated that if the printed circuit board is galvanically connected to the enclosure, the near-field scan must be performed under same conditions....

Experimental Study on Natural Convection Heat Transfer From two Parallel Horizontal Cylinders in Horizontal Cylindrical Enclosure

Directory of Open Access Journals (Sweden)

Ahmed T. Ahmed

2013-05-01

Full Text Available  An experimental study on natural convection heat transfer from two parallel horizontal cylinders in horizontal cylindrical enclosure was carried out under condition of constant surfaces temperature for two cylinders and cylindrical enclosure. The study included the effect of Rayleigh number, rotation angle that represent the confined angle between the passing horizontal plane in cylindrical enclosure center and passing line in two cylinders centers, and the spaces between two cylinders on their heat loss ability.39An experimental set-up was used for this purpose which consist watercontainer, test section which is formed of plastic cylinder that represent the cylindrical enclosure, and two heating elements which are formed of two copper cylinders with (19 mm in diameters heated internally by electrical sources that represents transfer and heat loss elements through this set-up.      The experiments were done at the range of Rayleigh number between ( , cylinders rotation angle at ( , and spacing ratio at ( .     The study showed that the ability of heat loss from two cylinders is a function of Rayleigh number, cylinders rotation angle, and the spaces between them. This ability is increased by increasing of Rayleigh number and it was showed that this ability reaches maximum value at the first cylinder ( and minimum value at the second cylinder ( at spacing ratio (S/D=3 and rotation angle ( for the first and ( for the second cylinder respectively.      The effective variables on natural convection heat transfer from the above two cylinders are related by two correlating equations, each one explains dimensionless relation of heat transfer from each cylinder that represented by Nusselt number against Rayleigh number, rotation angle, and the spacing ratio between two cylinders. 

Flat panel planar optic display

Energy Technology Data Exchange (ETDEWEB)

Veligdan, J.T. [Brookhaven National Lab., Upton, NY (United States). Dept. of Advanced Technology

1994-11-01

A prototype 10 inch flat panel Planar Optic Display, (POD), screen has been constructed and tested. This display screen is comprised of hundreds of planar optic class sheets bonded together with a cladding layer between each sheet where each glass sheet represents a vertical line of resolution. The display is 9 inches wide by 5 inches high and approximately 1 inch thick. A 3 milliwatt HeNe laser is used as the illumination source and a vector scanning technique is employed.

A new technique for determining orientation and motion of a 2-D, non-planar magnetopause

Directory of Open Access Journals (Sweden)

A. Blagau

2010-03-01

Full Text Available For a four-point mission like Cluster, the differences in position and time when the satellites detect the magnetopause or any other discontinuity, can be used to infer the discontinuity local orientation, thickness and motion. This timing technique, commonly assuming a planar geometry, offers an independent check for various single-spacecraft techniques. In the present paper we propose an extension of the timing method, capable of determining in a self-consistent way the macroscopic parameters of a two-dimensional, non-planar discontinuity. Such a configuration can be produced by a local bulge or indentation in the magnetopause, or by a large amplitude wave traveling on this surface, and is recognized in Cluster data when the single spacecraft techniques provide different individual normals contained roughly in the same plane. The model we adopted for the magnetopause assumes a layer of constant thickness of either cylindrical or parabolic shape, which has one or two degrees of freedom for the motion in the plane of the individual normals. The method was further improved by incorporating in a self-consistent way the requirement of minimum magnetic field variance along the magnetopause normal. An additional assumption, required in a previously proposed non-planar technique, i.e. that the non-planarity has negligible effects on the minimum variance analysis, is thus avoided. We applied the method to a magnetopause transition for which the various planar techniques provided inconsistent results. By contrast, the solutions obtained from the different implementations of the new 2-D method were consistent and stable, indicating a convex shape for the magnetopause. These solutions perform better than the planar solutions from the normal magnetic field variance perspective. The magnetopause dynamics and the presence of a non-zero normal magnetic field component in the analyzed event are discussed.

Planar Algebra of the Subgroup-Subfactor

Indian Academy of Sciences (India)

The crucial step in this identification is an exhibition of a model for the basic construction tower, and thereafter of the standard invariant of R ⋊ H ⊂ R ⋊ G in terms of operator matrices. We also obtain an identification between the planar algebra of the fixed algebra subfactor R G ⊂ R H and the -invariant planar subalgebra ...

Technical errors in planar bone scanning.

Science.gov (United States)

Naddaf, Sleiman Y; Collier, B David; Elgazzar, Abdelhamid H; Khalil, Magdy M

2004-09-01

Optimal technique for planar bone scanning improves image quality, which in turn improves diagnostic efficacy. Because planar bone scanning is one of the most frequently performed nuclear medicine examinations, maintaining high standards for this examination is a daily concern for most nuclear medicine departments. Although some problems such as patient motion are frequently encountered, the degraded images produced by many other deviations from optimal technique are rarely seen in clinical practice and therefore may be difficult to recognize. The objectives of this article are to list optimal techniques for 3-phase and whole-body bone scanning, to describe and illustrate a selection of deviations from these optimal techniques for planar bone scanning, and to explain how to minimize or avoid such technical errors.

Radiation exchange factors between specular inner surfaces of a rectangular enclosure such as transplant production unit

International Nuclear Information System (INIS)

Abdel-Ghany, Ahmed M.; Kozai, Toyoki

2006-01-01

General mathematical relations are presented for the specular exchange factors, F S , of diffuse radiation exchange between the inner surfaces of a rectangular enclosure. Three of these surfaces are specular reflectors, diffuse emitters and the fourth surface is a diffuse reflector, diffuse emitter. This enclosure can be used as a transplant production unit with artificial lighting for electric energy saving purposes. An image system and the crossed string method are used to derive these relations. The resulting expressions are conceptually simple and similar to the commonly known expressions of the exchange factors between diffuse surfaces, F. The accuracy of the presented F S relations was examined for different numbers of multiple reflections, N, on the specular surfaces and for different aspect ratios (ratio of the width, w to the height, h). The results proved that the relations are accurate and strongly satisfy the well-known relation of the radiation exchange between enclosure surfaces and satisfy the reciprocity relation. For any aspect ratio, considering N of 150 between highly reflective surfaces (ρ = 0.99) is sufficient to estimate the F S factors without any possible error. Using specular reflecting surfaces in such cases significantly reduces the electric energy consumption used for lighting

Natural convection in square enclosure induced by inner circular cylinder with time-periodic pulsating temperature

KAUST Repository

Huang, Zhu; Zhang, Wei; Xi, Guang

2015-01-01

The periodic unsteady natural convection flow and heat transfer in a square enclosure containing a concentric circular cylinder is numerically studied. The temperature of the inner circular cylinder fluctuates periodically with time at higher

Monte Carlo method for critical systems in infinite volume: The planar Ising model.

Science.gov (United States)

Herdeiro, Victor; Doyon, Benjamin

2016-10-01

In this paper we propose a Monte Carlo method for generating finite-domain marginals of critical distributions of statistical models in infinite volume. The algorithm corrects the problem of the long-range effects of boundaries associated to generating critical distributions on finite lattices. It uses the advantage of scale invariance combined with ideas of the renormalization group in order to construct a type of "holographic" boundary condition that encodes the presence of an infinite volume beyond it. We check the quality of the distribution obtained in the case of the planar Ising model by comparing various observables with their infinite-plane prediction. We accurately reproduce planar two-, three-, and four-point of spin and energy operators. We also define a lattice stress-energy tensor, and numerically obtain the associated conformal Ward identities and the Ising central charge.

Nonclassical-light generation in a photonic-band-gap nonlinear planar waveguide

International Nuclear Information System (INIS)

Perina, Jan Jr.; Sibilia, Concita; Tricca, Daniela; Bertolotti, Mario

2004-01-01

The optical parametric process occurring in a photonic-band-gap planar waveguide is studied from the point of view of nonclassical-light generation. The nonlinearly interacting optical fields are described by the generalized superposition of coherent signals and noise using the method of operator linear corrections to a classical strong solution. Scattered backward-propagating fields are taken into account. Squeezed light as well as light with sub-Poissonian statistics can be obtained in two-mode fields under the specified conditions

On Longest Cycles in Essentially 4-Connected Planar Graphs

Directory of Open Access Journals (Sweden)

Fabrici Igor

2016-08-01

Full Text Available A planar 3-connected graph G is essentially 4-connected if, for any 3-separator S of G, one component of the graph obtained from G by removing S is a single vertex. Jackson and Wormald proved that an essentially 4-connected planar graph on n vertices contains a cycle C such that . For a cubic essentially 4-connected planar graph G, Grünbaum with Malkevitch, and Zhang showed that G has a cycle on at least ¾ n vertices. In the present paper the result of Jackson and Wormald is improved. Moreover, new lower bounds on the length of a longest cycle of G are presented if G is an essentially 4-connected planar graph of maximum degree 4 or G is an essentially 4-connected maximal planar graph.

Guidelines for optimization of planar HDR implants

International Nuclear Information System (INIS)

Zwicker, R.D.; Schmidt-Ullrich, R.

1996-01-01

Purpose: Conventional low dose rate (LDR) planar Ir-192 implants are typically carried out using at most a few different source strengths. Remote afterloading offers a much higher degree of flexibility with individually programmable dwell times. Dedicated software is available to generate individual dwell times producing isodose surfaces which contour as closely as possible the target volume. The success of these algorithms in enclosing the target volume while sparing normal tissues is dependent on the positioning of the source guides which constrain the dwell points. In this work we provide source placement guidelines for optimal coverage and dose uniformity in planar high dose rate (HDR) implants. The resulting distributions are compared with LDR treatments in terms of dose uniformity and early and late tissue effects. Materials and methods: Computer studies were undertaken to determine source positions and dwell times for optimal dose uniformity in planar HDR implants, and the results were compared to those obtained using corresponding LDR implant geometries. The improvements in the dose distributions achieved with the remote after loader are expected to help offset the increased late tissue effects which can occur when LDR irradiation is replaced with a few large HDR fractions. Equivalent differential volume-dose (DVD) curves for early and late effects were calculated for different numbers of HDR fractions using a linear-quadratic model and compared to the corresponding curves for the LDR regime. Results: Tables of source placement parameters were generated as guidelines for achieving highly homogeneous planar HDR dose distributions. Differential volume-dose data generated inside the target volume provide a quantitative measure of the improvement in real dose homogeneity obtained with remote afterloading. The net result is a shift of the peak in the DVD curve toward lower doses relative to the LDR implant. The equivalent DVD curves for late effects obtained

Numerical study of different conduction models for Al_2O_3-water nanofluid with variable properties inside a trapezoidal enclosure

International Nuclear Information System (INIS)

Arani, Ali Akbar Abbasian; Azemati, Ali Akbar; Rezaee, Mohammad; Hadavand, Behzad Shirkavand

2017-01-01

Natural convection in enclosures containing nanofluids is important in physical and environmental applications. Different models for conduction have been developed because of the importance of this phenomenon in natural convection in enclosures. In this study, effects of conduction models of Chon, Corcione, Khanafer, and Koo and Kleinstreuer on the natural convection inside a trapezoidal enclosure with hot and cold walls are evaluated numerically. The enclosure contains Al_2O_3-water nanofluid with variable properties. Effects of the conduction models on fluid flow, natural convection, variations in volume fraction, and diameter of nanoparticles in the models, as well as the variations in the Rayleigh number, are examined. Results show that at Rayleigh numbers of 105 and 106, the maximum and minimum values of the average Nusselt number are obtained using the models of Khanafer and Chon, respectively. In all models, the average Nusselt number presents upward and downward trends when the volume fraction of nanoparticles increases but decreases when the di- ameter of the nanoparticles increases. At Ra = 105 in all models, as the volume fraction of nanoparticles increases, the nanofluid provides a higher average Nusselt number compared with the base fluid. By contrast, at Ra = 106, at volume fractions larger than 0.01 and using the model of Chon, the average Nusselt number of the nanofluid is lower compared with that of the base fluid.

Magnetometric prospection of various types of large ditch enclosures (or fortifications) in Bohemia

Czech Academy of Sciences Publication Activity Database

Křivánek, Roman

2003-01-01

Roč. 41, - (2003), s. 216-219 ISSN 0066-5924. [Archaeological Prospection. Kraków, 10.09.2003-14.09.2003] R&D Projects: GA ČR GV404/97/K024 Institutional research plan: CEZ:AV0Z8002910 Keywords : ditch enclosure * magnetometric prospection * fortification Subject RIV: AC - Archeology, Anthropology, Ethnology

Lattice Boltzmann simulation of natural convection in an L-shaped enclosure in the presence of nanofluid

Directory of Open Access Journals (Sweden)

Bouchmel Mliki

2015-09-01

Full Text Available In the present paper, fluid flow and heat transfer inside L-shaped enclosure filled with Cu/water nanofluid has been investigated numerically using the Lattice Boltzmann Method. The validity of the numerical code used is ascertained and good agreement was found with published results. The effects of different parameters such as Rayleigh number (103–106, aspect ratio of the L-shaped enclosure (0.2–0.6 and nanoparticle volume concentration (0–0.05 on the flow and temperature fields are studied. The obtained results show that nanofluid enhances the heat transfer amount and reducing the aspect ratio improves this effect. Also it was found that the mean Nusselt number increased with increase in Rayleigh number.

Planar half-cell shaped precursor body

DEFF Research Database (Denmark)

2015-01-01

The invention relates to a half-cell shaped precursor body of either anode type or cathode type, the half-cell shaped precursor body being prepared to be free sintered to form a sintered or pre-sintered half-cell being adapted to be stacked in a solid oxide fuel cell stack. The obtained half......-cell has an improved planar shape, which remains planar also after a sintering process and during temperature fluctuations....

Piezo Voltage Controlled Planar Hall Effect Devices.

Science.gov (United States)

Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K W; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

2016-06-22

The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

Attractive planar panelization using dynamic relaxation principles

NARCIS (Netherlands)

Gauss, Florian; Teuffel, Patrick

2015-01-01

In the presented paper a new method is proposed to approximate a given NURBS surface with a PQ (Planar Quad) mesh. The desired mesh layout will be generated in then attracted to the target surface. The process iteratively pulls the mesh vertices towards the target surface and then planarizes the

Planar Hall effect bridge magnetic field sensors

DEFF Research Database (Denmark)

Henriksen, A.D.; Dalslet, Bjarke Thomas; Skieller, D.H.

2010-01-01

Until now, the planar Hall effect has been studied in samples with cross-shaped Hall geometry. We demonstrate theoretically and experimentally that the planar Hall effect can be observed for an exchange-biased ferromagnetic material in a Wheatstone bridge topology and that the sensor signal can...... Hall effect bridge sensors....

Column Planarity and Partially-Simultaneous Geometric Embedding

Czech Academy of Sciences Publication Activity Database

Barba, L.; Evans, W.; Hoffmann, M.; Kusters, V.; Saumell, Maria; Speckmann, B.

2017-01-01

Roč. 21, č. 6 (2017), s. 983-1002 ISSN 1526-1719 Grant - others:GA MŠk(CZ) LO1506; GA MŠk(CZ) EE2.3.30.0038 Institutional support: RVO:67985807 Keywords : column planarity * unlabeled level planarity * simultaneous geometric embedding Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics

Pulsed laser planarization of metal films for multilevel interconnects

International Nuclear Information System (INIS)

Tuckerman, D.B.; Schmitt, R.L.

1985-05-01

Multilevel interconnect schemes for integrated circuits generally require one or more planarization steps, in order to maintain an acceptably flat topography for lithography and thin-film step coverage on the higher levels. Traditional approaches have involved planarization of the interlevel insulation (dielectric) layers, either by spin-on application (e.g., polyimide), or by reflow (e.g., phosphosilicate glass). We have pursued an alternative approach, in which each metal level is melted (hence planarized) using a pulsed laser prior to patterning. Short (approx.1 μs) pulses are used to preclude undesirable metallurgical reactions between the film, adhesion or barrier layer, and dielectric layer. Laser planarization of metals is particularly well suited to multilevel systems which include ground or power planes. Results are presented for planarization of gold films on SiO 2 dielectric layers using a flashlamp-pumped dye laser. The pulse duration is approx.1 μs, which allows the heat pulse to uniformly penetrate the gold while not penetrating substantially through the underlying SiO 2 (hence not perturbing the lower levels of metal). Excellent planarization of the gold films is achieved (less than 0.1 μm surface roughness, even starting with extreme topographic variations), as well as improved conductivity. To demonstrate the process, numerous planarized two-layer structures (transmission lines under a ground plane) were fabricated and characterized. 9 refs., 2 figs

Manual on shielded enclosures. Incorporating: Applications guide, procedures guide, basics guide

International Nuclear Information System (INIS)

1996-01-01

This publication is part of practical radiation safety manual series for different fields of application aimed primarily at persons handling radiation sources on a daily routine basis, which could at same time be used by the competent authorities, supporting their efforts in the radiation protection training of workers or medical assistance personnel or helping on-site management to set up local radiation protection rules. It is dedicated to shielding enclosures: their application and procedures guides

Efficient and stable solution-processed planar perovskite solar cells via contact passivation

KAUST Repository

Tan, Hairen; Jain, Ankit; Voznyy, Oleksandr; Lan, Xinzheng; Garcí a de Arquer, F. Pelayo; Fan, James Z.; Quintero-Bermudez, Rafael; Yuan, Mingjian; Zhang, Bo; Zhao, Yicheng; Fan, Fengjia; Li, Peicheng; Quan, Li Na; Zhao, Yongbiao; Lu, Zheng-Hong; Yang, Zhenyu; Hoogland, Sjoerd; Sargent, Edward H.

2017-01-01

Planar perovskite solar cells (PSCs) made entirely via solution processing at low temperatures (<150°C) offer promise for simple manufacturing, compatibility with flexible substrates, and perovskite-based tandem devices. However, these PSCs require an electron-selective layer that performs well with similar processing. We report a contact-passivation strategy using chlorine-capped TiO2 colloidal nanocrystal film that mitigates interfacial recombination and improves interface binding in low-temperature planar solar cells. We fabricated solar cells with certified efficiencies of 20.1 and 19.5% for active areas of 0.049 and 1.1 square centimeters, respectively, achieved via low-temperature solution processing. Solar cells with efficiency greater than 20% retained 90% (97% after dark recovery) of their initial performance after 500 hours of continuous room-temperature operation at their maximum power point under 1-sun illumination (where 1 sun is defined as the standard illumination at AM1.5, or 1 kilowatt/square meter).

Efficient and stable solution-processed planar perovskite solar cells via contact passivation

KAUST Repository

Tan, Hairen

2017-02-03

Planar perovskite solar cells (PSCs) made entirely via solution processing at low temperatures (<150°C) offer promise for simple manufacturing, compatibility with flexible substrates, and perovskite-based tandem devices. However, these PSCs require an electron-selective layer that performs well with similar processing. We report a contact-passivation strategy using chlorine-capped TiO2 colloidal nanocrystal film that mitigates interfacial recombination and improves interface binding in low-temperature planar solar cells. We fabricated solar cells with certified efficiencies of 20.1 and 19.5% for active areas of 0.049 and 1.1 square centimeters, respectively, achieved via low-temperature solution processing. Solar cells with efficiency greater than 20% retained 90% (97% after dark recovery) of their initial performance after 500 hours of continuous room-temperature operation at their maximum power point under 1-sun illumination (where 1 sun is defined as the standard illumination at AM1.5, or 1 kilowatt/square meter).

The effect of deltamethrin-treated net fencing around cattle enclosures on outdoor-biting mosquitoes in Kumasi, Ghana.

Directory of Open Access Journals (Sweden)

Marta Ferreira Maia

Full Text Available Classic vector control strategies target mosquitoes indoors as the main transmitters of malaria are indoor-biting and -resting mosquitoes. However, the intensive use of insecticide-treated bed-nets (ITNs and indoor residual spraying have put selective pressure on mosquitoes to adapt in order to obtain human blood meals. Thus, early-evening and outdoor vector activity is becoming an increasing concern. This study assessed the effect of a deltamethrin-treated net (100 mg/m(2 attached to a one-meter high fence around outdoor cattle enclosures on the number of mosquitoes landing on humans. Mosquitoes were collected from four cattle enclosures: Pen A - with cattle and no net; B - with cattle and protected by an untreated net; C - with cattle and protected by a deltamethrin-treated net; D - no cattle and no net. A total of 3217 culicines and 1017 anophelines were collected, of which 388 were Anopheles gambiae and 629 An. ziemanni. In the absence of cattle nearly 3 times more An. gambiae (p<0.0001 landed on humans. The deltamethrin-treated net significantly reduced (nearly three-fold, p<0.0001 culicine landings inside enclosures. The sporozoite rate of the zoophilic An. ziemanni, known to be a secondary malaria vector, was as high as that of the most competent vector An. gambiae; raising the potential of zoophilic species as secondary malaria vectors. After deployment of the ITNs a deltamethrin persistence of 9 months was observed despite exposure to African weather conditions. The outdoor use of ITNs resulted in a significant reduction of host-seeking culicines inside enclosures. Further studies investigating the effectiveness and spatial repellence of ITNs around other outdoor sites, such as bars and cooking areas, as well as their direct effect on vector-borne disease transmission are needed to evaluate its potential as an appropriate outdoor vector control tool for rural Africa.

Iteration of planar amplitudes in maximally supersymmetric Yang-Mills theory at three loops and beyond

International Nuclear Information System (INIS)

Bern, Zvi; Dixon, Lance J.; Smirnov, Vladimir A.

2005-01-01

We compute the leading-color (planar) three-loop four-point amplitude of N=4 supersymmetric Yang-Mills theory in 4-2ε dimensions, as a Laurent expansion about ε=0 including the finite terms. The amplitude was constructed previously via the unitarity method, in terms of two Feynman loop integrals, one of which has been evaluated already. Here we use the Mellin-Barnes integration technique to evaluate the Laurent expansion of the second integral. Strikingly, the amplitude is expressible, through the finite terms, in terms of the corresponding one- and two-loop amplitudes, which provides strong evidence for a previous conjecture that higher-loop planar N=4 amplitudes have an iterative structure. The infrared singularities of the amplitude agree with the predictions of Sterman and Tejeda-Yeomans based on resummation. Based on the four-point result and the exponentiation of infrared singularities, we give an exponentiated Ansatz for the maximally helicity-violating n-point amplitudes to all loop orders. The 1/ε 2 pole in the four-point amplitude determines the soft, or cusp, anomalous dimension at three loops in N=4 supersymmetric Yang-Mills theory. The result confirms a prediction by Kotikov, Lipatov, Onishchenko and Velizhanin, which utilizes the leading-twist anomalous dimensions in QCD computed by Moch, Vermaseren and Vogt. Following similar logic, we are able to predict a term in the three-loop quark and gluon form factors in QCD

9 CFR 3.14 - Primary enclosures used to transport live dogs and cats.

Science.gov (United States)

2010-01-01

... live dogs and cats. 3.14 Section 3.14 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION..., Treatment, and Transportation of Dogs and Cats 1 Transportation Standards § 3.14 Primary enclosures used to transport live dogs and cats. Any person subject to the Animal Welfare regulations (9 CFR parts 1, 2, and 3...

Investigations into the dynamics of aerosols in enclosures as used for air pollution studies

NARCIS (Netherlands)

Vate, van de J.F.

1980-01-01

This thesis treats aerosol behaviour under various conditions in enclosed spaces. Knowledge of this behaviour is of importance for the use of aerosol-filled enclosures as a supply of aerosol, as a means for aerosol characterization and for so-called smog chambers for air pollution research (mainly

Synthesis of the IRSN report related to the containment of double walled enclosures of the operated fleet

International Nuclear Information System (INIS)

2013-01-01

This report presents the IRSN's analysis on studies and modifications planned by EDF within the frame of the VD3-1300 safety re-examination which more particularly concern the third containment barrier of a reactor and of its extensions, as well as the containment of some surrounding buildings. The addressed topics are: the approach associated with the 'containment' safety function, the condition, behaviour and control of the double walled enclosure, the system of suction and filtration of the space between enclosures, the extension of the third containment barrier, the containment of building surrounding the reactor building, the risk of bypass containment, the EDF organisation with respect to the containment safety function

Planar Elongation Measurements on Soft Elastomers

DEFF Research Database (Denmark)

Jensen, Mette Krog; Skov, Anne Ladegaard; Rasmussen, Henrik K.

2009-01-01

A new fixture to the filament stretch rheometer (FSR) has been developed to measure planar elongation of soft polymeric networks. To validate this new technique, soft polymeric networks of poly(propyleneoxide) (PPO) were investigated during deformation.......A new fixture to the filament stretch rheometer (FSR) has been developed to measure planar elongation of soft polymeric networks. To validate this new technique, soft polymeric networks of poly(propyleneoxide) (PPO) were investigated during deformation....

Entropy Generation Analysis of Natural Convection in Square Enclosures with Two Isoflux Heat Sources

Directory of Open Access Journals (Sweden)

S. Z. Nejad

2017-04-01

Full Text Available This study investigates entropy generation resulting from natural convective heat transfer in square enclosures with local heating of the bottom and symmetrical cooling of the sidewalls. This analysis tends to optimize heat transfer of two pieces of semiconductor in a square electronic package. In this simulation, heaters are modeled as isoflux heat sources and sidewalls of the enclosure are isothermal heat sinks. The top wall and the non-heated portions of the bottom wall are adiabatic. Flow and temperature fields are obtained by numerical simulation of conservation equations of mass, momentum and energy in laminar, steady and two dimensional flows. With constant heat energy into the cavity, effect of Rayleigh number, heater length, heater strength ratios and heater position is evaluated on flow and temperature fields and local entropy generation. The results show that a minimum entropy generation rate is obtained under the same condition in which a minimum peak heater temperature is obtained.

Planar metasurface retroreflector

Science.gov (United States)

Arbabi, Amir; Arbabi, Ehsan; Horie, Yu; Kamali, Seyedeh Mahsa; Faraon, Andrei

2017-07-01

Metasurfaces are two-dimensional arrangements of subwavelength scatterers that control the propagation of optical waves. Here, we show that cascaded metasurfaces, each performing a predefined mathematical transformation, provide a new optical design framework that enables new functionalities not yet demonstrated with single metasurfaces. Specifically, we demonstrate that retroreflection can be achieved with two vertically stacked planar metasurfaces, the first performing a spatial Fourier transform and its inverse, and the second imparting a spatially varying momentum to the Fourier transform of the incident light. Using this concept, we fabricate and test a planar monolithic near-infrared retroreflector composed of two layers of silicon nanoposts, which reflects light along its incident direction with a normal incidence efficiency of 78% and a large half-power field of view of 60°. The metasurface retroreflector demonstrates the potential of cascaded metasurfaces for implementing novel high-performance components, and enables low-power and low-weight passive optical transmitters.

Incremental and batch planar simplification of dense point cloud maps

NARCIS (Netherlands)

Whelan, T.; Ma, L.; Bondarev, E.; With, de P.H.N.; McDonald, J.

2015-01-01

Dense RGB-D SLAM techniques and high-fidelity LIDAR scanners are examples from an abundant set of systems capable of providing multi-million point datasets. These datasets quickly become difficult to process due to the sheer volume of data, typically containing significant redundant information,

Three- and four-noded planar elements using absolute nodal coordinate formulation

International Nuclear Information System (INIS)

Olshevskiy, Alexander; Dmitrochenko, Oleg; Kim, Changwan

2013-01-01

This paper investigates two new types of planar finite elements containing three and four nodes. These elements are the reduced forms of the spatial plate elements employing the absolute nodal coordinate approach. Elements of the first type use translations of nodes and global slopes as nodal coordinates and have 18 and 24 degrees of freedom. The slopes facilitate the prevention of the shear locking effect in bending problems. Furthermore, the slopes accurately describe the deformed shape of the elements. Triangular and quadrilateral elements of the second type use translational degrees of freedom only and, therefore, can be utilized successfully in problems without bending. These simple elements with 6 and 8 degrees of freedom are identical to the elements used in conventional formulation of the finite element method from the kinematical point of view. Similarly to the famous problem called “flying spaghetti” which is used often as a benchmark for beam elements, a kind of “flying lasagna” is simulated for the planar elements. Numerical results of simulations are presented.

Chaotic non-planar vibrations of the thin elastica. Part I: Experimental observation of planar instability

Science.gov (United States)

Cusumano, J. P.; Moon, F. C.

1995-01-01

In this two-part paper, the results of an investigation into the non-linear dynamics of a flexible cantilevered rod (the elastica) with a thin rectangular cross-section are presented. An experimental examination of the dynamics of the elastica over a broad parameter range forms the core of Part I. In Part II, the experimental work is related to a theoretical study of the mechanics of the elastica, and the study of a two-degree-of-freedom model obtained by modal projection. The experimental system used in this investigation is a rod with clamped-free boundary conditions, forced by sinusoidally displacing the clamped end. Planar periodic motions of the driven elastica are shown to lose stability at distinct resonant wedges, and the resulting motions are shown in general to be non-planar, chaotic, bending-torsion oscillations. Non-planar motions in all resonances exhibit energy cascading and dynamic two-well phenomena, and a family of asymmetric, bending-torsion non-linear modes is discovered. Correlation dimension calculations are used to estimate the number of active degrees of freedom in the system.

Computational Study on a PTAS for Planar Dominating Set Problem

Directory of Open Access Journals (Sweden)

Qian-Ping Gu

2013-01-01

Full Text Available The dominating set problem is a core NP-hard problem in combinatorial optimization and graph theory, and has many important applications. Baker [JACM 41,1994] introduces a k-outer planar graph decomposition-based framework for designing polynomial time approximation scheme (PTAS for a class of NP-hard problems in planar graphs. It is mentioned that the framework can be applied to obtain an O(2ckn time, c is a constant, (1+1/k-approximation algorithm for the planar dominating set problem. We show that the approximation ratio achieved by the mentioned application of the framework is not bounded by any constant for the planar dominating set problem. We modify the application of the framework to give a PTAS for the planar dominating set problem. With k-outer planar graph decompositions, the modified PTAS has an approximation ratio (1 + 2/k. Using 2k-outer planar graph decompositions, the modified PTAS achieves the approximation ratio (1+1/k in O(22ckn time. We report a computational study on the modified PTAS. Our results show that the modified PTAS is practical.

Development of simulators algorithms of planar radioactive sources for use in computer models of exposure; Desenvolvimento de algoritmos simuladores de fontes radioativas planares para uso em modelos computacionais de exposicao

Energy Technology Data Exchange (ETDEWEB)

Vieira, Jose Wilson; Leal Neto, Viriato; Lima Filho, Jose de Melo, E-mail: jose.wilson59@uol.com.br [Instituto Federal de Educacao Ciencia e Tecnologia de Pernambuco (IFPE), Recife, PE (Brazil); Lima, Fernando Roberto de Andrade [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

2013-07-01

This paper presents as algorithm of a planar and isotropic radioactive source and by rotating the probability density function (PDF) Gaussian standard subjected to a translatory method which displaces its maximum throughout its field changes its intensity and makes the dispersion around the mean right asymmetric. The algorithm was used to generate samples of photons emerging from a plane and reach a semicircle involving a phantom voxels. The PDF describing this problem is already known, but the generating function of random numbers (FRN) associated with it can not be deduced by direct MC techniques. This is a significant problem because it can be adjusted to simulations involving natural terrestrial radiation or accidents in medical establishments or industries where the radioactive material spreads in a plane. Some attempts to obtain a FRN for the PDF of the problem have already been implemented by the Research Group in Numerical Dosimetry (GND) from Recife-PE, Brazil, always using the technique rejection sampling MC. This article followed methodology of previous work, except on one point: The problem of the PDF was replaced by a normal PDF transferred. To perform dosimetric comparisons, we used two MCES: the MSTA (Mash standing, composed by the adult male voxel phantom in orthostatic position, MASH (male mesh), available from the Department of Nuclear Energy (DEN) of the Federal University of Pernambuco (UFPE), coupled to MC EGSnrc code and the GND planar source based on the rejection technique) and MSTA{sub N}T. The two MCES are similar in all but FRN used in planar source. The results presented and discussed in this paper establish the new algorithm for a planar source to be used by GND.

Belief propagation and loop series on planar graphs

International Nuclear Information System (INIS)

Chertkov, Michael; Teodorescu, Razvan; Chernyak, Vladimir Y

2008-01-01

We discuss a generic model of Bayesian inference with binary variables defined on edges of a planar graph. The Loop Calculus approach of Chertkov and Chernyak (2006 Phys. Rev. E 73 065102(R) [cond-mat/0601487]; 2006 J. Stat. Mech. P06009 [cond-mat/0603189]) is used to evaluate the resulting series expansion for the partition function. We show that, for planar graphs, truncating the series at single-connected loops reduces, via a map reminiscent of the Fisher transformation (Fisher 1961 Phys. Rev. 124 1664), to evaluating the partition function of the dimer-matching model on an auxiliary planar graph. Thus, the truncated series can be easily re-summed, using the Pfaffian formula of Kasteleyn (1961 Physics 27 1209). This allows us to identify a big class of computationally tractable planar models reducible to a dimer model via the Belief Propagation (gauge) transformation. The Pfaffian representation can also be extended to the full Loop Series, in which case the expansion becomes a sum of Pfaffian contributions, each associated with dimer matchings on an extension to a subgraph of the original graph. Algorithmic consequences of the Pfaffian representation, as well as relations to quantum and non-planar models, are discussed

9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.

Science.gov (United States)

2010-01-01

... live guinea pigs and hamsters. 3.36 Section 3.36 Animals and Animal Products ANIMAL AND PLANT HEALTH..., Care, Treatment, and Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.36 Primary enclosures used to transport live guinea pigs and hamsters. No person subject to the Animal Welfare...

An Educational Laboratory Experiment to Demonstrate the Development of Fires in a Long Enclosure

Science.gov (United States)

Moinuddin, Khalid

2013-01-01

This paper is aimed at describing an experiment involving flame-front movement across the fuel package located within long enclosures and associated heat transfer mechanism. There is a growing interest in incorporating safety education in the chemical engineering curriculum, especially in relation to "facility siting." This experiment is…

Planar quantum squeezing and atom interferometry

Energy Technology Data Exchange (ETDEWEB)

He, Q. Y.; Drummond, P. D.; Reid, M. D. [ARC Centre of Excellence for Quantum-Atom Optics, Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia); Peng Shiguo [Department of Physics, Tsinghua University, Beijing 100084 (China)

2011-08-15

We obtain a lower bound on the sum of two orthogonal spin component variances in a plane. This gives a planar uncertainty relation which holds even when the Heisenberg relation is not useful. We investigate the asymptotic, large-J limit and derive the properties of the planar quantum squeezed states that saturate this uncertainty relation. These states extend the concept of spin squeezing to any two conjugate spin directions. We show that planar quantum squeezing can be achieved experimentally as the ground state of a Bose-Einstein condensate in two coupled potential wells with a critical attractive interaction. These states reduce interferometric phase noise at all phase angles simultaneously. This is useful for one-shot interferometric phase measurements where the measured phase is completely unknown. Our results can also be used to derive entanglement criteria for multiple spins J at separated sites, with applications in quantum information.

Searching for planar signatures in WMAP

International Nuclear Information System (INIS)

Abramo, L. Raul; Bernui, Armando; Pereira, Thiago S.

2009-01-01

We search for planar deviations of statistical isotropy in the Wilkinson Microwave Anisotropy Probe (WMAP) data by applying a recently introduced angular-planar statistics both to full-sky and to masked temperature maps, including in our analysis the effect of the residual foreground contamination and systematics in the foreground removing process as sources of error. We confirm earlier findings that full-sky maps exhibit anomalies at the planar (l) and angular (l) scales (l,l) = (2,5),(4,7), and (6,8), which seem to be due to unremoved foregrounds since this features are present in the full-sky map but not in the masked maps. On the other hand, our test detects slightly anomalous results at the scales (l,l) = (10,8) and (2,9) in the masked maps but not in the full-sky one, indicating that the foreground cleaning procedure (used to generate the full-sky map) could not only be creating false anomalies but also hiding existing ones. We also find a significant trace of an anomaly in the full-sky map at the scale (l,l) = (10,5), which is still present when we consider galactic cuts of 18.3% and 28.4%. As regards the quadrupole (l = 2), we find a coherent over-modulation over the whole celestial sphere, for all full-sky and cut-sky maps. Overall, our results seem to indicate that current CMB maps derived from WMAP data do not show significant signs of anisotropies, as measured by our angular-planar estimator. However, we have detected a curious coherence of planar modulations at angular scales of the order of the galaxy's plane, which may be an indication of residual contaminations in the full- and cut-sky maps

Reduction of truncation errors in planar near-field aperture antenna measurements using the method of alternating orthogonal projections

DEFF Research Database (Denmark)

Martini, Enrica; Breinbjerg, Olav; Maci, Stefano

2006-01-01

A simple and effective procedure for the reduction of truncation error in planar near-field to far-field transformations is presented. The starting point is the consideration that the actual scan plane truncation implies a reliability of the reconstructed plane wave spectrum of the field radiated...

Substrate and coating defect planarization strategies for high-laser-fluence multilayer mirrors

International Nuclear Information System (INIS)

Stolz, Christopher J.; Wolfe, Justin E.; Mirkarimi, Paul B.; Folta, James A.; Adams, John J.; Menor, Marlon G.; Teslich, Nick E.; Soufli, Regina; Menoni, Carmen S.; Patel, Dinesh

2015-01-01

Planarizing or smoothing over nodular defects in multilayer mirrors can be accomplished by a discrete deposit-and-etch process that exploits the angle-dependent etching rate of optical materials. Typically, nodular defects limit the fluence on mirrors irradiated at 1064 nm with 10 ns pulse lengths due to geometrically- and interference-induced light intensification. Planarized hafina/silica multilayer mirrors have demonstrated > 125 J/cm 2 laser resistance for single-shot testing and 50 J/cm 2 for multi-shot testing for nodular defects originating on the substrate surface. Two planarization methods were explored: thick planarization layers on the substrate surface and planarized silica layers throughout the multilayer in which only the silica layers that are below one half of the incoming electric field value are etched. This paper also describes the impact of planarized defects that are buried within the multilayer structure compared to planarized substrate particulate defects. - Highlights: • Defect planarization significantly improves multilayer mirror laser resistance • Substrate and coating defects have both been effectively planarized • Single and multishot laser resistance improvement was demonstrated

A graph-based method for fitting planar B-spline curves with intersections

Directory of Open Access Journals (Sweden)

Pengbo Bo

2016-01-01

Full Text Available The problem of fitting B-spline curves to planar point clouds is studied in this paper. A novel method is proposed to deal with the most challenging case where multiple intersecting curves or curves with self-intersection are necessary for shape representation. A method based on Delauney Triangulation of data points is developed to identify connected components which is also capable of removing outliers. A skeleton representation is utilized to represent the topological structure which is further used to create a weighted graph for deciding the merging of curve segments. Different to existing approaches which utilize local shape information near intersections, our method considers shape characteristics of curve segments in a larger scope and is thus capable of giving more satisfactory results. By fitting each group of data points with a B-spline curve, we solve the problems of curve structure reconstruction from point clouds, as well as the vectorization of simple line drawing images by drawing lines reconstruction.

High precision target center determination from a point cloud

Directory of Open Access Journals (Sweden)

K. Kregar

2013-10-01

Full Text Available Many applications of terrestrial laser scanners (TLS require the determination of a specific point from a point cloud. In this paper procedure of high precision planar target center acquisition from point cloud is presented. The process is based on an image matching algorithm but before we can deal with raster image to fit a target on it, we need to properly determine the best fitting plane and project points on it. The main emphasis of this paper is in the precision estimation and propagation through the whole procedure which allows us to obtain precision assessment of final results (target center coordinates. Theoretic precision estimations – obtained through the procedure were rather high so we compared them with the empiric precision estimations obtained as standard deviations of results of 60 independently scanned targets. An χ2-test confirmed that theoretic precisions are overestimated. The problem most probably lies in the overestimated precisions of the plane parameters due to vast redundancy of points. However, empirical precisions also confirmed that the proposed procedure can ensure a submillimeter precision level. The algorithm can automatically detect grossly erroneous results to some extent. It can operate when the incidence angles of a laser beam are as high as 80°, which is desirable property if one is going to use planar targets as tie points in scan registration. The proposed algorithm will also contribute to improve TLS calibration procedures.

Planar strain analysis of liver undergoing microwave thermal ablation using x-ray CT.

Science.gov (United States)

Weiss, Noam; Goldberg, S Nahum; Nissenbaum, Yitzhak; Sosna, Jacob; Azhari, Haim

2015-01-01

To study the planar strain effects in liver during microwave (MW) thermal ablation as a means for tracking tissue expansion and contraction as a method for improving ablation monitoring. 1.4 mm circular metallic markers were inserted into 16 ex-vivo bovine fresh liver specimens, that were subsequently ablated (with the markers inside the specimen) by 40 W of microwave energy, for 1, 2, 3, 6, and 10 min. The markers were tracked during the ablation using an x-ray CT scanner. Images were acquired every 5-10 s enabling determination of the markers' coordinates over time. The 2D principal strains were calculated for triangles formed by subgroups of three markers, and their planar strain index, Ω, was plotted vs time. In addition, the radial distance of the markers from the antenna was measured at the end of each ablation. Subsequently, the tissue was sliced parallel to the imaged planes and the ablation zone was traced and digitized. The average ablation radius was then computed and compared to the radial distance. The planar strain, Ω(t), profile demonstrated an ascending pattern until reaching a maximum at about 180 s, with a mean peak value (Ω = 1.31 ± 0.04) indicating tissue expansion. Thereafter, Ω progressively declined over the remaining duration of the ablation treatment, indicating tissue contraction. Furthermore, when plotting the ablation size vs time and the markers' mean radial distance vs time, it was found that the two curves intercepted at a time corresponding to the time of peak planar strain. By detecting the point of maximal planar strain in tissues during MW application, it is possible to noninvasively identify the location of the ablation zone front. The fact that the liver tissue proximal to the ablated zone expands during the first part of the treatment and then contracts when the ablation front reaches it, may serve as an index for monitoring the thermal treatment.

Two-phase strategy of neural control for planar reaching movements: I. XY coordination variability and its relation to end-point variability.

Science.gov (United States)

Rand, Miya K; Shimansky, Yury P

2013-03-01

A quantitative model of optimal transport-aperture coordination (TAC) during reach-to-grasp movements has been developed in our previous studies. The utilization of that model for data analysis allowed, for the first time, to examine the phase dependence of the precision demand specified by the CNS for neurocomputational information processing during an ongoing movement. It was shown that the CNS utilizes a two-phase strategy for movement control. That strategy consists of reducing the precision demand for neural computations during the initial phase, which decreases the cost of information processing at the expense of lower extent of control optimality. To successfully grasp the target object, the CNS increases precision demand during the final phase, resulting in higher extent of control optimality. In the present study, we generalized the model of optimal TAC to a model of optimal coordination between X and Y components of point-to-point planar movements (XYC). We investigated whether the CNS uses the two-phase control strategy for controlling those movements, and how the strategy parameters depend on the prescribed movement speed, movement amplitude and the size of the target area. The results indeed revealed a substantial similarity between the CNS's regulation of TAC and XYC. First, the variability of XYC within individual trials was minimal, meaning that execution noise during the movement was insignificant. Second, the inter-trial variability of XYC was considerable during the majority of the movement time, meaning that the precision demand for information processing was lowered, which is characteristic for the initial phase. That variability significantly decreased, indicating higher extent of control optimality, during the shorter final movement phase. The final phase was the longest (shortest) under the most (least) challenging combination of speed and accuracy requirements, fully consistent with the concept of the two-phase control strategy. This paper

Measure Guideline. Deep Energy Enclosure Retrofit for Interior Insulation of Masonry Walls

Energy Technology Data Exchange (ETDEWEB)

Musunuru, S. [Building Science Corporation, Westford, MA (United States); Pettit, B. [Building Science Corporation, Westford, MA (United States)

2015-04-30

This Measure Guideline describes a deep energy enclosure retrofit solution for insulating mass masonry buildings from the interior. It describes the retrofit assembly, technical details, and installation sequence for retrofitting masonry walls. Interior insulation of masonry retrofits might adversely affect the durability of the wall. This guideline includes a review of decision criteria pertinent to retrofitting masonry walls from the interior and the possible risk of freeze-thaw damage.

Beyond level planarity

NARCIS (Netherlands)

Angelini, P.; Da Lozzo, G.; Di Battista, G.; Frati, F.; Patrignani, M.; Rutter, I.; Hu, Y.; Nöllenburg, M.

2016-01-01

In this paper we settle the computational complexity of two open problems related to the extension of the notion of level planarity to surfaces different from the plane. Namely, we show that the problems of testing the existence of a level embedding of a level graph on the surface of the rolling

Experimental low-frequency sound equalization in an extended region of an enclosure using adaptive filters

DEFF Research Database (Denmark)

Orozco-Santillán, Arturo

1998-01-01

An experimental investigation of sound equalization in an extended region inside an enclosure is presented. DSP and the multiple LMS algorithm is used to obtain the optimal solution. Equalization at single frequencies in the stationary state is studied. Also analyzed is the equalization of band...

Field-induced quantum criticality of a spin-1/2 planar ferromagnet

International Nuclear Information System (INIS)

Mercaldo, M T; Rabuffo, I; Cesare, L De; D'Auria, A Caramico

2009-01-01

The low-temperature critical properties and crossovers of a spin- 1/2 planar ferromagnet in a longitudinal magnetic field are explored in terms of an anisotropic bosonic action, suitable to describe the spin model in the low-temperature regime. This is performed adopting a procedure which combines an averaging over dynamic degrees of freedom and the classical Wilson renormalization group transformation. Within this framework we get the phase boundary, ending in a quantum critical point, and general expressions for the correlation length and susceptibility as functions of the temperature and the applied magnetic field within the disordered phase. In particular, two crossovers occur decreasing the temperature with the magnetic field fixed at its quantum critical point value, which might be actually observable in complex magnetic compounds, as suggested by recent experiments.

Evaluation of cardiac function using multi-shot echo planar imaging

Energy Technology Data Exchange (ETDEWEB)

Nakanishi, Tadashi; Tanitame, Nobuko; Hata, Ryoichiro; Hirai, Nobuhiko; Ikeda, Midori; Ono, Chiaki; Fukuoka, Haruhito; Ito, Katsuhide [Hiroshima Univ. (Japan). School of Medicine

1998-01-01

In this study, we performed multi-shot echo planar imaging (8 shot, TR/TE/FL=55 ms/18 ms/60 degrees) and k-space segmented fast gradient echo sequence (8 views per segment, TR/TE/FL=9.9 ms/1.8 ms/30 degrees) to assess cardiac function in healthy volunteers. Transaxial sections of the entire heart were obtained with both sequences in ECG triggered, breath hold, and with a 256 x 128 matrix. Resulting temporal resolution was 55 ms for echo planar imaging, and 71 ms for k-space segmented fast gradient echo sequence, respectively. Ventricular volume and ejection fraction of both ventricles and left ventricular mass obtained with multi-shot echo planar imaging were assessed in comparison with k-space segmented fast gradient echo sequence. Measurements of left ventricular volume, ejection fraction and mass obtained with multi-shot echo planar imaging demonstrated close correlation with those obtained with k-space segmented fast gradient echo sequence. Right ventricular volumes obtained with echo planar imaging were significantly higher than those obtained with k-space segmented fast gradient echo sequence. This tendency is considered to be due to differing contrast between right ventricular myocardium and fat tissue observed with echo planar imaging relative to that observed with fast gradient echo sequence, because fat suppression is always performed in echo planar images. Multi-shot echo planar imaging can be a reliable tool for measurement of cardiac functional parameters, although wall motion analysis of the left ventricle requires higher temporal resolution and a short axial section. (K.H.)

Energy and economic analysis of a building enclosure outfitted with a phase change material board (PCMB)

International Nuclear Information System (INIS)

Sun, Xiaoqin; Zhang, Quan; Medina, Mario A.; Lee, Kyoung Ok

2014-01-01

Highlights: • Phase change material boards (PCMBs) were simulated in building enclosures. • Energy and economic savings for these buildings were estimated. • The buildings were located in five cities with different climatic conditions. • The energy savings ratio was 100% when a cold energy source was used. • A mean electricity savings ratio of 13.1% was obtained. - Abstract: This paper presents energy and economic analyses related to the application of phase change materials boards (PCMBs) in building enclosures during the cooling season. A heat transfer model was developed, which was implemented via a computer program. Simulations were carried out using weather data files from five cities located in five different climate regions in China. Energy savings from using a natural cold source (e.g., outdoor air) and electricity savings from a reduction in electricity by air conditioning systems were evaluated. The energy savings ratio (ESR) and simple payback period (SPP) were used to assess the application of PCMBs in building enclosures. The selection of optimum phase transition temperatures for the PCMs for the various climates was made using indoor and outdoor air temperatures, as well as SPP. For space cooling purposes, it was suggested that phase transition temperatures should be at least 3 °C higher than the mean outdoor air temperature. Simple payback period suggested the possibility of the cost effective use of PCMBs in occupied buildings for moderate temperature climates

Generators for finite depth subfactor planar algebras

Indian Academy of Sciences (India)

The main result of Kodiyalam and Tupurani [3] shows that a subfactor planar algebra of finite depth is singly generated with a finite presentation. If P is a subfactor planar algebra of depth k, it is shown there that a single 2k-box generates P. It is natural to ask what the smallest s is such that a single s-box generates P. While ...

An integrated experimental and computational approach to material selection for sound proof thermally insulted enclosure of a power generation system

Science.gov (United States)

Waheed, R.; Tarar, W.; Saeed, H. A.

2016-08-01

Sound proof canopies for diesel power generators are fabricated with a layer of sound absorbing material applied to all the inner walls. The physical properties of the majority of commercially available sound proofing materials reveal that a material with high sound absorption coefficient has very low thermal conductivity. Consequently a good sound absorbing material is also a good heat insulator. In this research it has been found through various experiments that ordinary sound proofing materials tend to rise the inside temperature of sound proof enclosure in certain turbo engines by capturing the heat produced by engine and not allowing it to be transferred to atmosphere. The same phenomenon is studied by creating a finite element model of the sound proof enclosure and performing a steady state and transient thermal analysis. The prospects of using aluminium foam as sound proofing material has been studied and it is found that inside temperature of sound proof enclosure can be cut down to safe working temperature of power generator engine without compromise on sound proofing.

Mixed convection from a discrete heat source in enclosures with two adjacent moving walls and filled with micropolar nanofluids

Directory of Open Access Journals (Sweden)

Sameh E. Ahmed

2016-03-01

Full Text Available This paper examines numerically the thermal and flow field characteristics of the laminar steady mixed convection flow in a square lid-driven enclosure filled with water-based micropolar nanofluids by using the finite volume method. While a uniform heat source is located on a part of the bottom of the enclosure, both the right and left sidewalls are considered adiabatic together with the remaining parts of the bottom wall. The upper wall is maintained at a relatively low temperature. Both the upper and left sidewalls move at a uniform lid-driven velocity and four different cases of the moving lid ordinations are considered. The fluid inside the enclosure is a water based micropolar nanofluid containing different types of solid spherical nanoparticles: Cu, Ag, Al2O3, and TiO2. Based on the numerical results, the effects of the dominant parameters such as Richardson number, nanofluid type, length and location of the heat source, solid volume fractions, moving lid orientations and dimensionless viscosity are examined. Comparisons with previously numerical works are performed and good agreements between the results are observed. It is found that the average Nusselt number along the heat source decreases as the heat source length increases while it increases when the solid volume fraction increases. Also, the results of the present study indicate that both the local and the average Nusselt numbers along the heat source have the highest value for the fourth case (C4. Moreover, it is observed that both the Richardson number and moving lid ordinations have a significant effect on the flow and thermal fields in the enclosure.

Existence of Resonance Stability of Triangular Equilibrium Points in Circular Case of the Planar Elliptical Restricted Three-Body Problem under the Oblate and Radiating Primaries around the Binary System

Directory of Open Access Journals (Sweden)

A. Narayan

2014-01-01

Full Text Available This paper analyzes the existence of resonance stability of the triangular equilibrium points of the planar elliptical restricted three-body problem when both the primaries are oblate spheroid as well as the source of radiation under the particular case, when e=0. We have derived Hamiltonian function describing the motion of infinitesimal mass in the neighborhood of the triangular equilibrium solutions taken as a convergent series. Hamiltonian function for the system has been derived and also expanded in powers of the generalized components of momenta. We have used canonical transformation to make the Hamiltonian function independent of true anomaly. The most interesting and distinguishable results of this study are establishing the relation for determining the range of stability at and near the resonance ω2=1/2 around the binary system.

Evanescent field refractometry in planar optical fiber.

Science.gov (United States)

Holmes, Christopher; Jantzen, Alexander; Gray, Alan C; Gow, Paul C; Carpenter, Lewis G; Bannerman, Rex H S; Gates, James C; Smith, Peter G R

2018-02-15

This Letter demonstrates a refractometer in integrated optical fiber, a new optical platform that planarizes fiber using flame hydrolysis deposition (FHD). The unique advantage of the technology is survivability in harsh environments. The platform is mechanically robust, and can survive elevated temperatures approaching 1000°C and exposure to common solvents, including acetone, gasoline, and methanol. For the demonstrated refractometer, fabrication was achieved through wet etching an SMF-28 fiber to a diameter of 8 μm before FHD planarization. An external refractive index was monitored using fiber Bragg gratings (FBGs), written into the core of the planarized fiber. A direct comparison to alternative FBG refractometers is made, for which the developed platform is shown to have comparable sensitivity, with the added advantage of survivability in harsh environments.

Measure Guideline: Deep Energy Enclosure Retrofit for Interior Insulation of Masonry Walls

Energy Technology Data Exchange (ETDEWEB)

Musunuru, S. [Building Science Corporation, Westford, MA (United States); Pettit, B. [Building Science Corporation, Westford, MA (United States)

2015-04-01

This Measure Guideline describes a deep energy enclosure retrofit (DEER) solution for insulating mass masonry buildings from the interior. It describes the retrofit assembly, technical details, and installation sequence for retrofitting masonry walls. Interior insulation of masonry retrofits has the potential to adversely affect the durability of the wall; this document includes a review of decision criteria pertinent to retrofitting masonry walls from the interior and the possible risk of freeze-thaw damage.

The Complete Four-Loop Four-Point Amplitude in N

Energy Technology Data Exchange (ETDEWEB)

Bern, Z.; Carrasco, J.J.M.; /UCLA; Dixon, Lance J.; /SLAC /CERN; Johansson, H.; /Saclay, SPhT; Roiban, R.; /Penn State U.

2010-08-25

We present the complete four-loop four-point amplitude in N = 4 super-Yang-Mills theory, for a general gauge group and general D-dimensional covariant kinematics, and including all non-planar contributions. We use the method of maximal cuts - an efficient application of the unitarity method - to construct the result in terms of 50 four-loop integrals. We give graphical rules, valid in D-dimensions, for obtaining various non-planar contributions from previously-determined terms. We examine the ultraviolet behavior of the amplitude near D = 11/2. The non-planar terms are as well-behaved in the ultraviolet as the planar terms. However, in the color decomposition of the three- and four-loop amplitude for an SU(N{sub c}) gauge group, the coefficients of the double-trace terms are better behaved in the ultraviolet than are the single-trace terms. The results from this paper were an important step toward obtaining the corresponding amplitude in N = 8 supergravity, which confirmed the existence of cancellations beyond those needed for ultraviolet finiteness at four loops in four dimensions. Evaluation of the loop integrals near D = 4 would permit tests of recent conjectures and results concerning the infrared behavior of four-dimensional massless gauge theory.

Entropy Error Model of Planar Geometry Features in GIS

Institute of Scientific and Technical Information of China (English)

LI Dajun; GUAN Yunlan; GONG Jianya; DU Daosheng

2003-01-01

Positional error of line segments is usually described by using "g-band", however, its band width is in relation to the confidence level choice. In fact, given different confidence levels, a series of concentric bands can be obtained. To overcome the effect of confidence level on the error indicator, by introducing the union entropy theory, we propose an entropy error ellipse index of point, then extend it to line segment and polygon,and establish an entropy error band of line segment and an entropy error donut of polygon. The research shows that the entropy error index can be determined uniquely and is not influenced by confidence level, and that they are suitable for positional uncertainty of planar geometry features.

Nonlinear Saturation Amplitude in Classical Planar Richtmyer–Meshkov Instability

International Nuclear Information System (INIS)

Liu Wan-Hai; Jiang Hong-Bin; Ma Wen-Fang; Wang Xiang

2016-01-01

The classical planar Richtmyer–Meshkov instability (RMI) at a fluid interface supported by a constant pressure is investigated by a formal perturbation expansion up to the third order, and then according to definition of nonlinear saturation amplitude (NSA) in Rayleigh–Taylor instability (RTI), the NSA in planar RMI is obtained explicitly. It is found that the NSA in planar RMI is affected by the initial perturbation wavelength and the initial amplitude of the interface, while the effect of the initial amplitude of the interface on the NSA is less than that of the initial perturbation wavelength. Without marginal influence of the initial amplitude, the NSA increases linearly with wavelength. The NSA normalized by the wavelength in planar RMI is about 0.11, larger than that corresponding to RTI. (paper)

The peeling process of infinite Boltzmann planar maps

DEFF Research Database (Denmark)

Budd, Timothy George

2016-01-01

criterion has a very simple interpretation. The finite random planar maps under consideration were recently proved to possess a well-defined local limit known as the infinite Boltzmann planar map (IBPM). Inspired by recent work of Curien and Le Gall, we show that the peeling process on the IBPM can...

Numerical study of different conduction models for Al{sub 2}O{sub 3}-water nanofluid with variable properties inside a trapezoidal enclosure

Energy Technology Data Exchange (ETDEWEB)

Arani, Ali Akbar Abbasian; Azemati, Ali Akbar; Rezaee, Mohammad [University of Kashan, Kashan (Iran, Islamic Republic of); Hadavand, Behzad Shirkavand [Islamic Azad University, Abadan (Iran, Islamic Republic of)

2017-05-15

Natural convection in enclosures containing nanofluids is important in physical and environmental applications. Different models for conduction have been developed because of the importance of this phenomenon in natural convection in enclosures. In this study, effects of conduction models of Chon, Corcione, Khanafer, and Koo and Kleinstreuer on the natural convection inside a trapezoidal enclosure with hot and cold walls are evaluated numerically. The enclosure contains Al{sub 2}O{sub 3}-water nanofluid with variable properties. Effects of the conduction models on fluid flow, natural convection, variations in volume fraction, and diameter of nanoparticles in the models, as well as the variations in the Rayleigh number, are examined. Results show that at Rayleigh numbers of 105 and 106, the maximum and minimum values of the average Nusselt number are obtained using the models of Khanafer and Chon, respectively. In all models, the average Nusselt number presents upward and downward trends when the volume fraction of nanoparticles increases but decreases when the di- ameter of the nanoparticles increases. At Ra = 105 in all models, as the volume fraction of nanoparticles increases, the nanofluid provides a higher average Nusselt number compared with the base fluid. By contrast, at Ra = 106, at volume fractions larger than 0.01 and using the model of Chon, the average Nusselt number of the nanofluid is lower compared with that of the base fluid.

Transition to chaos in a square enclosure containing internal heat sources

Energy Technology Data Exchange (ETDEWEB)

Baytas, A.C. [Institute For Nuclear Energy, Istanbul (Turkey)

1995-09-01

A numerical investigation is performed to study the transition from steady to chaotic flow of a fluid confined in a two-dimensional square cavity. The cavity has rigid walls of constant temperature containing uniformly distributed internal heat source. Effects of the Rayleigh number of flow and heat transfer rates are studied. In addition to, same problem is solved for sinusoidally changing internal heat source to show its effect on the flow model and heat transfer of the enclosures. Details of oscillatory solutions and flow bifurcations are presented.

Planar dynamical systems selected classical problems

CERN Document Server

Liu, Yirong; Huang, Wentao

2014-01-01

This book presents in an elementary way the recent significant developments in the qualitative theory of planar dynamical systems. The subjects are covered as follows: the studies of center and isochronous center problems, multiple Hopf bifurcations and local and global bifurcations of the equivariant planar vector fields which concern with Hilbert's 16th problem. This book is intended for graduate students, post-doctors and researchers in the area of theories and applications of dynamical systems. For all engineers who are interested the theory of dynamical systems, it is also a reasona

Current in heavy-current planar diode with discrete emission surface

International Nuclear Information System (INIS)

Belomyttsev, S.Ya.; Korovin, S.D.; Pegel', I.V

1999-01-01

Dependence of current in a high-current planar diode on the size of emission centres was studied. Essential effect of emission surface microstructure on the current value in the planar diode was demonstrated. It was determined that if the distance between the emitter essentially exceeded their size then current dependence on the ratio of size to the value of the diode gap was an exponential function with 3/2 index. Current dependence on voltage obeyed the exponential law with 3/2 index up to higher voltage values in the planar diode with discrete emission surface in contrast to the case of a planar diode with homogeneous emission surface [ru

The Sheath-less Planar Langmuir Probe

Science.gov (United States)

Cooke, D. L.

2017-12-01

The Langmuir probe is one of the oldest plasma diagnostics, provided the plasma density and species temperature from analysis of a current-voltage curve as the voltage is swept over a practically chosen range. The analysis depends on a knowledge or theory of the many factors that influence the current-voltage curve including, probe shape, size, nearby perturbations, and the voltage reference. For applications in Low Earth Orbit, the Planar Langmuir Probe, PLP, is an attractive geometry because the ram ion current is very constant over many Volts of a sweep, allowing the ion density and electron temperature to be determined independently with the same instrument, at different points on the sweep. However, when the physical voltage reference is itself small and electrically floating as with a small spacecraft, the spacecraft and probe system become a double probe where the current collection theory depends on the interaction of the spacecraft with the plasma which is generally not as simple as the probe itself. The Sheath-less PLP, SPLP, interlaces on a single ram facing surface, two variably biased probe elements, broken into many small and intertwined segments on a scale smaller than the plasma Debye length. The SPLP is electrically isolated from the rest of the spacecraft. For relative bias potentials of a few volts, the ion current to all segments of each element will be constant, while the electron currents will vary as a function of the element potential and the electron temperature. Because the segments are small, intertwined, and floating, the assembly will always present the same floating potential to the plasma, with minimal growth as a function of voltage, thus sheath-less and still planar. This concept has been modelled with Nascap, and tested with a physical model inserted into a Low Earth Orbit-like chamber plasma. Results will be presented.

Point defect relaxation volumes for copper

International Nuclear Information System (INIS)

Miller, K.M.

1979-11-01

The methods used for the determination of point defect relaxation volumes are discussed and it is shown that a previous interatomic potential derived for copper is inaccurate and results obtained using it are invalid. A new interatomic potential has been produced for copper and a computer simulation of point and planar defects carried out. A vacancy relaxation volume of -0.33 atomic volumes has been found with interstitial values in the range 1.7 to 2.0 atomic volumes. It is shown that these values in current theories of irradiation induced swelling lead to an anomalously high value for dislocation bias compared with that determined experimentally. (author)

Exchange factor method: an alternative zonal formulation for analysis of radiating enclosures containing participating media

International Nuclear Information System (INIS)

Larsen, M.E.

1983-01-01

The exchange factor method (EFM) is introduced and compared to the zone method (ZM). In both the EFM and ZM the region of interest is discretized into volume and surface elements, each considered to be isothermal, which are small enough to give the required resolution. A suitable set of state variables for the system is composed of the surface element radiosities and the gas element emissive powers. The EFM defines exchange factors as dimensionless total-exchange areas for radiant interchange between volume and surface elements by all possible absorption/re-emission paths, but excluding wall reflections. In the EFM, the exchange factors replace the direct-exchange areas of the ZM and are used to write energy balances for each area and volume element in the system. As in the ZM, the radiant energy balance equations result in a set of algebraic equations linear in the system state variables. The distinguishing feature of the EFM is that exchange factors may be measurable quantities. Relationships between the EFM exchange factors and the ZM direct-exchange areas are presented. EFM conservation and reciprocity laws, analogous to those of the ZM, are also included. Temperature and heat flux distributions, predicted using the EFM, for two- and three-dimensional enclosures containing absorbing/emitting, isotropically scattering, and conducting media are included. An application of the EFM is proposed which calls for the measurement of exchange factors in a scale model of the enclosure to be analyzed. The measurement of these factors in an enclosure containing an isotropically scattering medium is discussed. The effects of isotropic scattering and absorption/re-emission processes are shown to be indistinguishable in their contribution to exchange factor paths

Constructing IGA-suitable planar parameterization from complex CAD boundary by domain partition and global/local optimization

Science.gov (United States)

Xu, Gang; Li, Ming; Mourrain, Bernard; Rabczuk, Timon; Xu, Jinlan; Bordas, Stéphane P. A.

2018-01-01

In this paper, we propose a general framework for constructing IGA-suitable planar B-spline parameterizations from given complex CAD boundaries consisting of a set of B-spline curves. Instead of forming the computational domain by a simple boundary, planar domains with high genus and more complex boundary curves are considered. Firstly, some pre-processing operations including B\\'ezier extraction and subdivision are performed on each boundary curve in order to generate a high-quality planar parameterization; then a robust planar domain partition framework is proposed to construct high-quality patch-meshing results with few singularities from the discrete boundary formed by connecting the end points of the resulting boundary segments. After the topology information generation of quadrilateral decomposition, the optimal placement of interior B\\'ezier curves corresponding to the interior edges of the quadrangulation is constructed by a global optimization method to achieve a patch-partition with high quality. Finally, after the imposition of C1=G1-continuity constraints on the interface of neighboring B\\'ezier patches with respect to each quad in the quadrangulation, the high-quality B\\'ezier patch parameterization is obtained by a C1-constrained local optimization method to achieve uniform and orthogonal iso-parametric structures while keeping the continuity conditions between patches. The efficiency and robustness of the proposed method are demonstrated by several examples which are compared to results obtained by the skeleton-based parameterization approach.

Optimization of electronic enclosure design for thermal and moisture management using calibrated models of progressive complexity

DEFF Research Database (Denmark)

Mohanty, Sankhya; Staliulionis, Zygimantas; Shojaee Nasirabadi, Parizad

2016-01-01

the development of rigorous calibrated CFD models as well as simple predictive numerical tools, the current paper tackles the optimization of critical features of a typical two-chamber electronic enclosure. The progressive optimization strategy begins the design parameter selection by initially using simpler...

Planar Submillimeter-Wave Mixer Technology with Integrated Antenna

Science.gov (United States)

Chattopadhyay, Gautam; Mehdi, Imran; Gill, John J.; Lee, Choonsup; lombart, Muria L.; Thomas, Betrand

2010-01-01

High-performance mixers at terahertz frequencies require good matching between the coupling circuits such as antennas and local oscillators and the diode embedding impedance. With the availability of amplifiers at submillimeter wavelengths and the need to have multi-pixel imagers and cameras, planar mixer architecture is required to have an integrated system. An integrated mixer with planar antenna provides a compact and optimized design at terahertz frequencies. Moreover, it leads to a planar architecture that enables efficient interconnect with submillimeter-wave amplifiers. In this architecture, a planar slot antenna is designed on a thin gallium arsenide (GaAs) membrane in such a way that the beam on either side of the membrane is symmetric and has good beam profile with high coupling efficiency. A coplanar waveguide (CPW) coupled Schottky diode mixer is designed and integrated with the antenna. In this architecture, the local oscillator (LO) is coupled through one side of the antenna and the RF from the other side, without requiring any beam sp litters or diplexers. The intermediate frequency (IF) comes out on a 50-ohm CPW line at the edge of the mixer chip, which can be wire-bonded to external circuits. This unique terahertz mixer has an integrated single planar antenna for coupling both the radio frequency (RF) input and LO injection without any diplexer or beamsplitters. The design utilizes novel planar slot antenna architecture on a 3- mthick GaAs membrane. This work is required to enable future multi-pixel terahertz receivers for astrophysics missions, and lightweight and compact receivers for planetary missions to the outer planets in our solar system. Also, this technology can be used in tera hertz radar imaging applications as well as for testing of quantum cascade lasers (QCLs).

Hydrogenated arsenenes as planar magnet and Dirac material

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shengli; Cai, Bo; Zeng, Haibo, E-mail: Huziyu@csrc.ac.cn, E-mail: zeng.haibo@njust.edu.cn [Institute of Optoelectronics and Nanomaterials, Herbert Gleiter Institute of Nanoscience, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Hu, Yonghong [Institute of Optoelectronics and Nanomaterials, Herbert Gleiter Institute of Nanoscience, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); School of Nuclear Technology and Chemistry and Biology, Hubei University of Science and Technology, Xianning 437100 (China); Hu, Ziyu, E-mail: Huziyu@csrc.ac.cn, E-mail: zeng.haibo@njust.edu.cn [Beijing Computational Science Research Center, Beijing 100084 (China)

2015-07-13

Arsenene and antimonene are predicted to have 2.49 and 2.28 eV band gaps, which have aroused intense interest in the two-dimensional (2D) semiconductors for nanoelectronic and optoelectronic devices. Here, the hydrogenated arsenenes are reported to be planar magnet and 2D Dirac materials based on comprehensive first-principles calculations. The semi-hydrogenated (SH) arsenene is found to be a quasi-planar magnet, while the fully hydrogenated (FH) arsenene is a planar Dirac material. The buckling height of pristine arsenene is greatly decreased by the hydrogenation, resulting in a planar and relatively low-mass-density sheet. The electronic structures of arsenene are also evidently altered after hydrogenating from wide-band-gap semiconductor to metallic material for SH arsenene, and then to Dirac material for FH arsenene. The SH arsenene has an obvious magnetism, mainly contributed by the p orbital of the unsaturated As atom. Such magnetic and Dirac materials modified by hydrogenation of arsenene may have potential applications in future optoelectronic and spintronic devices.

Hydrogenated arsenenes as planar magnet and Dirac material

International Nuclear Information System (INIS)

Zhang, Shengli; Cai, Bo; Zeng, Haibo; Hu, Yonghong; Hu, Ziyu

2015-01-01

Arsenene and antimonene are predicted to have 2.49 and 2.28 eV band gaps, which have aroused intense interest in the two-dimensional (2D) semiconductors for nanoelectronic and optoelectronic devices. Here, the hydrogenated arsenenes are reported to be planar magnet and 2D Dirac materials based on comprehensive first-principles calculations. The semi-hydrogenated (SH) arsenene is found to be a quasi-planar magnet, while the fully hydrogenated (FH) arsenene is a planar Dirac material. The buckling height of pristine arsenene is greatly decreased by the hydrogenation, resulting in a planar and relatively low-mass-density sheet. The electronic structures of arsenene are also evidently altered after hydrogenating from wide-band-gap semiconductor to metallic material for SH arsenene, and then to Dirac material for FH arsenene. The SH arsenene has an obvious magnetism, mainly contributed by the p orbital of the unsaturated As atom. Such magnetic and Dirac materials modified by hydrogenation of arsenene may have potential applications in future optoelectronic and spintronic devices

Hydrogenated arsenenes as planar magnet and Dirac material

Science.gov (United States)

Zhang, Shengli; Hu, Yonghong; Hu, Ziyu; Cai, Bo; Zeng, Haibo

2015-07-01

Arsenene and antimonene are predicted to have 2.49 and 2.28 eV band gaps, which have aroused intense interest in the two-dimensional (2D) semiconductors for nanoelectronic and optoelectronic devices. Here, the hydrogenated arsenenes are reported to be planar magnet and 2D Dirac materials based on comprehensive first-principles calculations. The semi-hydrogenated (SH) arsenene is found to be a quasi-planar magnet, while the fully hydrogenated (FH) arsenene is a planar Dirac material. The buckling height of pristine arsenene is greatly decreased by the hydrogenation, resulting in a planar and relatively low-mass-density sheet. The electronic structures of arsenene are also evidently altered after hydrogenating from wide-band-gap semiconductor to metallic material for SH arsenene, and then to Dirac material for FH arsenene. The SH arsenene has an obvious magnetism, mainly contributed by the p orbital of the unsaturated As atom. Such magnetic and Dirac materials modified by hydrogenation of arsenene may have potential applications in future optoelectronic and spintronic devices.

The number of colorings of planar graphs with no separating triangles

DEFF Research Database (Denmark)

Thomassen, Carsten

2017-01-01

A classical result of Birkhoff and Lewis implies that every planar graph with . n vertices has at least . 152n-1 distinct 5-vertex-colorings. Equality holds for planar triangulations with . n-4 separating triangles. We show that, if a planar graph has no separating triangle, then it has at least ...

Planar waveguides and other confined geometries theory, technology, production, and novel applications

CERN Document Server

2015-01-01

This book provides a comprehensive overview of the theoretical concepts and experimental applications of planar waveguides and other confined geometries, such as optical fibres. Covering a broad array of advanced topics, it begins with a sophisticated discussion of planar waveguide theory, and covers subjects including efficient production of planar waveguides, materials selection, nonlinear effects, and applications including species analytics down to single-molecule identification, and thermo-optical switching using planar waveguides. Written by specialists in the techniques and applications covered, this book will be a useful resource for advanced graduate students and researchers studying planar waveguides and optical fibers.

Determination of crystallographic and macroscopic orientation of planar structures in TEM

DEFF Research Database (Denmark)

Huang, X.; Liu, Q.

1998-01-01

With the aid of a double-tilt holder in a transmission electron microscope (TEM), simple methods are described for determination of the crystallographic orientation of a planar structure and for calculation of the macroscopic orientation of the planar structure. The correlation between a planar...... structure and a crystallographic plane can be found by comparing the differences in their trace directions on the projection plane and inclination angles with respect to that plane. The angles between the traces of planar structures and the sample axis measured from the TEM micrographs, which have been...

Manufacturing of planar ceramic interconnects

Energy Technology Data Exchange (ETDEWEB)

Armstrong, B.L.; Coffey, G.W.; Meinhardt, K.D.; Armstrong, T.R. [Pacific Northwest National Lab., Richland, WA (United States)

1996-12-31

The fabrication of ceramic interconnects for solid oxide fuel cells (SOFC) and separator plates for electrochemical separation devices has been a perennial challenge facing developers. Electrochemical vapor deposition (EVD), plasma spraying, pressing, tape casting and tape calendering are processes that are typically utilized to fabricate separator plates or interconnects for the various SOFC designs and electrochemical separation devices. For sake of brevity and the selection of a planar fuel cell or gas separation device design, pressing will be the only fabrication technique discussed here. This paper reports on the effect of the characteristics of two doped lanthanum manganite powders used in the initial studies as a planar porous separator for a fuel cell cathode and as a dense interconnect for an oxygen generator.

The influence of roughness, angle, range, and transducer type on the echo signal from planar interfaces

DEFF Research Database (Denmark)

Wilhjelm, Jens E.; Pedersen, Peter C.; Jacobsen, Søren Mehl

2001-01-01

B width for a 25.4 mm diameter 5-MHz planar and focused transducer was approximately 0.5/spl deg/ and 4/spl deg/ (at the focal point), respectively. E(0/spl deg/) as a function of surface roughness, R/sub q/, was nearly linear on a decibel scale, with a slope of -109 dB/(R/sub q///spl lambda/) and -61 d...

Measure Guideline. Deep Energy Enclosure Retrofit for Zero Energy Ready House Flat Roofs

Energy Technology Data Exchange (ETDEWEB)

Loomis, H. [Building Science Corporation, Westford, MA (United States); Pettit, B. [Building Science Corporation, Westford, MA (United States)

2015-05-29

This Measure Guideline provides design and construction information for a deep energy enclosure retrofit solution of a flat roof assembly. It describes the strategies and procedures for an exterior retrofit of a flat wood-framed roof with brick masonry exterior walls using exterior and interior (framing cavity) insulation. The approach supported in this guide could also be adapted for use with flat wood-framed roofs with wood-framed exterior walls.

Measure Guideline: Deep Energy Enclosure Retrofit for Zero Energy Ready House Flat Roofs

Energy Technology Data Exchange (ETDEWEB)

Loomis, H. [Building Science Corporation, Westford, MA (United States); Pettit, B. [Building Science Corporation, Westford, MA (United States)

2015-05-01

This Measure Guideline provides design and construction information for a deep energy enclosure retrofit (DEER) solution of a flat roof assembly. It describes the strategies and procedures for an exterior retrofit of a flat, wood-framed roof with brick masonry exterior walls, using exterior and interior (framing cavity) insulation. The approach supported in this guide could also be adapted for use with flat, wood-framed roofs with wood-framed exterior walls.

Planar hydrodynamic instability computations and experiments with rugby-shaped hohlraums at the Omega laser

International Nuclear Information System (INIS)

Vandenboomgaerde, M; Liberatore, S; Galmiche, D; Casner, A; Huser, G; Jadaud, J P; Villette, B

2008-01-01

Implosion of inertial confinement fusion (ICF) capsule is very sensitive to the growth of sphericity perturbations. The control of the feeding of such perturbations and their transport ('feedthrough') through the ablator is a key point to reach ignition. Since 2002, experiments have been designed and performed on the Omega laser facility in order to study these phenomena in planar geometry. A new 'rugby shaped' hohlraum was used. We present experimental results and comparisons with numerical simulations

NUMERICAL STUDY OF NON-DARCIAN NATURAL CONVECTION HEAT TRANSFER IN A RECTANGULAR ENCLOSURE FILLED WITH POROUS MEDIUM SATURATED WITH VISCOUS FLUID

Directory of Open Access Journals (Sweden)

Mahmood H. Ali

2015-02-01

Full Text Available A numerical study of non-Darcian natural convection heat transfer in a rectangular enclosure filled with porous medium saturated with viscous fluid was carried out. The effects of medium Rayleigh number, porosity, particle to fluid thermal conductivity ratio, Darcy number and enclosure aspect ratio on heat transfer were examined to demonstrate the ability of using this construction in thermal insulation of buildings walls.A modified Brinkman-Forchheimer-extended Darcy flow model was used and no-slip boundary conditions were imposed for velocity at the walls and the governing equations were expressed in dimensionless stream function, vorticity, and temperature formulation. The resulting algebraic equations obtained from finite difference discritization of vorticity and temperature equations are solved using (ADI method which uses Three Diagonal Matrix Algorithm (TDMA in each direction, while that of the stream function equation solved using successive iteration method.The study was done for the range of enclosure aspect ratio ( which is in the tall layers region at medium Rayleigh number ( , Darcy number (Da=10-3, 10-4, 10-5 , porosity (e=0.35, 0.45, 0.55, particle to fluid thermal conductivity (kS/kf=5.77, 38.5, 1385.5.The results showed that the Nusselt number is direct proportional to medium Rayleigh number and porosity and reversely proportional to Darcy number, ratio of particle to fluid thermal conductivity and enclosure aspect ratio. The variables that affect the heat transfer in the above arrangement was correlated in a mathematical equation that account better for their affects on heat transfer which is represented by mean Nusselt number (Nu.

The effects of varied densities on the growth and emigration of adult cutthroat trout and brook trout in fenced stream enclosures

Science.gov (United States)

Buys, D.J.; Hilderbrand, R.H.; Kershner, J.L.

2009-01-01

We evaluated the effects of various density treatments on adult fish growth and emigration rates between Bonneville cutthroat trout Oncorhynchus clarki utah and brook trout Salvelinus fontinalis in stream enclosures in Beaver Creek, Idaho, We used 3 density treatments (low, ambient, and high fish densities) to evaluate density-related effects and to ensure a response. Intraspecific ambient-density tests using cutthroat trout only were also performed. Results indicated an absence of cage effects in the stream enclosures and no differences in fish growth between ambient-density stream-enclosure fish and free-range fish. Brook trout outgrew and moved less than cutthroat trout in the stream enclosures, especially as density increased, In all 3 density treatments, brook trout gained more weight than cutthroat trout, with brook trout gaining weight in each density treatment and cutthroat trout losing weight at the highest density. At high densities, cutthroat trout attempted to emigrate more frequently than brook trout in sympatry and allopatry. We observed a negative correlation between growth and emigration for interspecific cutthroat trout, indicating a possible competitive response due to the presence of brook trout. We observed similar responses for weight and emigration in trials of allopatric cutthroat trout, indicating strong intraspecific effects as density increased. While cutthroat trout showed a response to experimental manipulation with brook trout at different densities, there has been long-term coexistence between these species in Beaver Creek, This system presents a unique opportunity to study the mechanisms that lead cutthroat trout to coexist with rather than be replaced by nonnative brook trout.

A study of coFeB magnetic yoke based on planar electromagnet

Science.gov (United States)

Qin, L.; Li, Q.; Yuan, Yong J.

2017-07-01

This paper studies the fabrication of a novel planar electromagnet consisting of a planar copper coil and a magnetic yoke. CoFeB was used as the magnetic yoke material instead of the traditional permanent magnets. The planar electromagnet was fabricated and optimized to maximize the electromagnetic force, especially with varying CoFeB thickness. The micro-planar electromagnet was fabricated successfully by the traditional micro-electro-mechanical-system (MEMS) techniques and XRD, VSM were used to characterize the performance of the electromagnet. The planar electromagnet exhibits superior perpendicular magnetic anisotropy (PMA) and 0.006 emu of MS was achieved following 2 min deposition of CoFeB thin film. By integrating with other micro apparatuses, it is anticipated that the planar electromagnet will have potential applications in areas such as biosensors, biological medicine, drug delivery, chemical analysis and environmental monitoring.

Application of the bootstrap method to radiolabeled antibody dosimetry from planar images

International Nuclear Information System (INIS)

Papenfuss, T.; Saunder, T.H.; Schleyer, P.J.; O'Keefe, G.J.; Scott, A.M.

2002-01-01

Full text: Planar imaging dosimetry of radiolabeled antibody treatment uses the MIRD schema to compute dose to an organ from the calculated activity in that and other organs. The calculated activity in an organ is a function of the average count rates in the organ, a standard and an appropriate background measurement. The geometric mean of conjugate averages, together with an attenuation factor is used to provide an approximate attenuation correction. It is sometimes desirable to know the variance of the activity in an organ in order to apply weighted least squares regression to the data. This is particularly important when incorporating more accurate data from autoradiography of biopsied tissue into the analysis, but is also useful when some data points have low signal. While the geometric mean image can be used to calculate the variance of an organ's count rate. It is difficult to calculate the variance of the activity, since the organ in question, the standard and the background all contribute to it. Bootstrap methods are Monte Carlo techniques that can be used to estimate parameters from data and to determine the accuracy of the estimation. By bootstrapping pixel values in the organ, background and standard ROIs, it is possible to calculate many realisations of the organ activity and calculate its variance. As an example, bootstrapping is applied to the pharmacodynamic analysis of 131 I-huA33 in colon. The data includes planar whole body images, and autoradiographs and planar images of a resected colon. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

Measure Guideline: Deep Energy Enclosure Retrofit for Double-Stud Walls

Energy Technology Data Exchange (ETDEWEB)

Loomis, H. [Building Science Corporation, Westford, MA (United States); Pettit, B. [Building Science Corporation, Westford, MA (United States)

2015-06-01

This Measure Guideline describes a deep energy enclosure retrofit (DEER) solution that provides insulation to the interior of the wall assembly with the use of a double stud wall. The guide describes two approaches to retrofitting the existing the walls: one involving replacement of the existing cladding, and the other that leaves the existing cladding in place. It discusses the design principles related to the use of various insulation types, and provides strategies and procedures for implementing the double stud wall retrofit. It also evaluates important moisture-related and indoor air quality measures that need to be implemented to achieve a durable, high performance wall.

Measure Guideline: Deep Energy Enclosure Retrofit for Double-Stud Walls

Energy Technology Data Exchange (ETDEWEB)

Loomis, H. [Building Science Corporation, Westford, MA (United States); Pettit, B. [Building Science Corporation, Westford, MA (United States)

2015-06-22

This Measure Guideline describes a deep energy enclosure retrofit solution that provides insulation to the interior of the wall assembly with the use of a double-stud wall. The guide describes two approaches to retrofitting the existing walls—one that involves replacing the existing cladding and the other that leaves the cladding in place. This guideline also covers the design principles related to the use of various insulation types and provides strategies and procedures for implementing the double-stud wall retrofit. It also includes an evaluation of important moisture-related and indoor air quality measures that need to be implemented to achieve a durable high-performance wall.

Design and measurements of the double layer planar motor

NARCIS (Netherlands)

Rovers, J.M.M.; Jansen, J.W.; Lomonova, E.

2013-01-01

Moving-magnet magnetically levitated planar motors are considered for use as a wafer stage in the semiconductor lithographic industry. This puts high requirements on the accuracy and the dissipated power and cooling performance of such motors. A novel planar motor topology is developed, which

Bifurcation theory for finitely smooth planar autonomous differential systems

Science.gov (United States)

Han, Maoan; Sheng, Lijuan; Zhang, Xiang

2018-03-01

In this paper we establish bifurcation theory of limit cycles for planar Ck smooth autonomous differential systems, with k ∈ N. The key point is to study the smoothness of bifurcation functions which are basic and important tool on the study of Hopf bifurcation at a fine focus or a center, and of Poincaré bifurcation in a period annulus. We especially study the smoothness of the first order Melnikov function in degenerate Hopf bifurcation at an elementary center. As we know, the smoothness problem was solved for analytic and C∞ differential systems, but it was not tackled for finitely smooth differential systems. Here, we present their optimal regularity of these bifurcation functions and their asymptotic expressions in the finite smooth case.

Conformal, planarizing and bridging AZ5214-E layers deposited by a 'draping' technique on non-planar III V substrates

Science.gov (United States)

Eliás, P.; Strichovanec, P.; Kostic, I.; Novák, J.

2006-12-01

A draping technique was tested for the deposition of positive-tone AZ5214-E photo-resist layers on non-planar (1 0 0)-oriented III-V substrates, which had a variety of three-dimensional (3D) topographies micromachined in them that consisted, e.g., of mesa ridges confined to side facets with variable tilt, inverted pyramidal holes and stubs confined to perpendicular side facets. All objects were sharp-edged. In each draping experiment, an AZ5214-E sheet was (1) formed floating on the water surface, (2) lowered onto a non-planar substrate and (3) draped over it during drying to form either self-sustained, or conformal, or planarizing layers over the non-planar substrates. The draping process is based on the depression of the glass transition temperature Tg of AZ5214-E material induced by penetrant water molecules that interact with AZ5214-E. During the process, the molecules are initially trapped under an AZ5214-E sheet and then transported out through the sheet via permeation. The water-AZ5214-E interaction modifies the stiffness κ of the sheet. The magnitude of the effect depends on temperature T and on partial water vapour pressure difference p(T, P, κ): the net effect is that Tg = f(C(T, P), p(T, P, κ)) is lowered as the concentration C of water increases with T and p, where P is the permeability of the sheet. The interaction depressed the Tg of the sheets as low as or lower than 53 °C for 6 µm thick sheets. At room temperature T Tg, the sheet becomes rubbery and mouldable by adhesion and capillary forces. As a result, it can either contour or planarize the topography depending on its geometry and thickness of the sheet.

Sputtering an exterior metal coating on copper enclosure for large-scale growth of single-crystalline graphene

DEFF Research Database (Denmark)

Luo, Birong; Caridad, José M; Whelan, Patrick Rebsdorf

2017-01-01

growth. The sputtered coating suppresses nucleation density by acting as both a diffusion barrier and as a sink for excess carbon during the growth, reducing the carbon concentration in the interior of the enclosure. Field effect mobility of hBN-templated devices fabricated from graphene domains grown...

Fluorescence based fiber optic and planar waveguide biosensors. A review

International Nuclear Information System (INIS)

Benito-Peña, Elena; Valdés, Mayra Granda; Glahn-Martínez, Bettina; Moreno-Bondi, Maria C.

2016-01-01

The application of optical biosensors, specifically those that use optical fibers and planar waveguides, has escalated throughout the years in many fields, including environmental analysis, food safety and clinical diagnosis. Fluorescence is, without doubt, the most popular transducer signal used in these devices because of its higher selectivity and sensitivity, but most of all due to its wide versatility. This paper focuses on the working principles and configurations of fluorescence-based fiber optic and planar waveguide biosensors and will review biological recognition elements, sensing schemes, as well as some major and recent applications, published in the last ten years. The main goal is to provide the reader a general overview of a field that requires the joint collaboration of researchers of many different areas, including chemistry, physics, biology, engineering, and material science. - Highlights: • Principles, configurations and fluorescence techniques using fiber optic and planar waveguide biosensors are discussed. • The biorecognition elements and sensing schemes used in fiber optic and planar waveguide platforms are reviewed. • Some major and recent applications of fiber optic and planar waveguide biosensors are introduced.

Fluorescence based fiber optic and planar waveguide biosensors. A review

Energy Technology Data Exchange (ETDEWEB)

Benito-Peña, Elena [Department of Analytical Chemistry, Faculty of Chemistry, Complutense University, 28040 Madrid (Spain); Valdés, Mayra Granda [Department of Analytical Chemistry, Faculty of Chemistry, University of La Habana, 10400 La Habana (Cuba); Glahn-Martínez, Bettina [Department of Analytical Chemistry, Faculty of Chemistry, Complutense University, 28040 Madrid (Spain); Moreno-Bondi, Maria C., E-mail: mcmbondi@quim.ucm.es [Department of Analytical Chemistry, Faculty of Chemistry, Complutense University, 28040 Madrid (Spain)

2016-11-02

The application of optical biosensors, specifically those that use optical fibers and planar waveguides, has escalated throughout the years in many fields, including environmental analysis, food safety and clinical diagnosis. Fluorescence is, without doubt, the most popular transducer signal used in these devices because of its higher selectivity and sensitivity, but most of all due to its wide versatility. This paper focuses on the working principles and configurations of fluorescence-based fiber optic and planar waveguide biosensors and will review biological recognition elements, sensing schemes, as well as some major and recent applications, published in the last ten years. The main goal is to provide the reader a general overview of a field that requires the joint collaboration of researchers of many different areas, including chemistry, physics, biology, engineering, and material science. - Highlights: • Principles, configurations and fluorescence techniques using fiber optic and planar waveguide biosensors are discussed. • The biorecognition elements and sensing schemes used in fiber optic and planar waveguide platforms are reviewed. • Some major and recent applications of fiber optic and planar waveguide biosensors are introduced.

Effect of flow rate on environmental variables and phytoplankton dynamics: results from field enclosures

Science.gov (United States)

Zhang, Haiping; Chen, Ruihong; Li, Feipeng; Chen, Ling

2015-03-01

To investigate the effects of flow rate on phytoplankton dynamics and related environment variables, a set of enclosure experiments with different flow rates were conducted in an artificial lake. We monitored nutrients, temperature, dissolved oxygen, pH, conductivity, turbidity, chlorophyll- a and phytoplankton levels. The lower biomass in all flowing enclosures showed that flow rate significantly inhibited the growth of phytoplankton. A critical flow rate occurred near 0.06 m/s, which was the lowest relative inhibitory rate. Changes in flow conditions affected algal competition for light, resulting in a dramatic shift in phytoplankton composition, from blue-green algae in still waters to green algae in flowing conditions. These findings indicate that critical flow rate can be useful in developing methods to reduce algal bloom occurrence. However, flow rate significantly enhanced the inter-relationships among environmental variables, in particular by inducing higher water turbidity and vegetative reproduction of periphyton ( Spirogyra). These changes were accompanied by a decrease in underwater light intensity, which consequently inhibited the photosynthetic intensity of phytoplankton. These results warn that a universal critical flow rate might not exist, because the effect of flow rate on phytoplankton is interlinked with many other environmental variables.

Modeling and optimization of planar microcoils

International Nuclear Information System (INIS)

Beyzavi, Ali; Nguyen, Nam-Trung

2008-01-01

Magnetic actuation has emerged as a useful tool for manipulating particles, droplets and biological samples in microfluidics. A planar coil is one of the suitable candidates for magnetic actuation and has the potential to be integrated in digital microfluidic devices. A simple model of microcoils is needed to optimize their use in actuation applications. This paper first develops an analytical model for calculating the magnetic field of a planar microcoil. The model was validated by experimental data from microcoils fabricated on printed circuit boards (PCB). The model was used for calculating the field strength and the force acting on a magnetic object. Finally, the effect of different coil parameters such as the magnitude of the electric current, the gap between the wires and the number of wire segments is discussed. Both analytical and experimental results show that a smaller gap size between wire segments, more wire segments and a higher electric current can increase both the magnitude and the gradient of the magnetic field, and consequently cause a higher actuating force. The planar coil analyzed in the paper is suitable for applications in magnetic droplet-based microfluidics

A continuous exchange factor method for radiative exchange in enclosures with participating media

International Nuclear Information System (INIS)

Naraghi, M.H.N.; Chung, B.T.F.; Litkouhi, B.

1987-01-01

A continuous exchange factor method for analysis of radiative exchange in enclosures is developed. In this method two types of exchange functions are defined, direct exchange function and total exchange function. Certain integral equations relating total exchange functions to direct exchange functions are developed. These integral equations are solved using Gaussian quadrature integration method. The results obtained based on the present approach are found to be more accurate than those of the zonal method

Testing of the rectangular pivot-point bellows for the PPPL tokamak fusion test reactor

International Nuclear Information System (INIS)

Haughian, J.; Lou, K.; Greer, J.; Fong, M.; Scalise, D.T.

1983-12-01

The Neutral Beam Pivot Point Bellows (PPB) is installed in the duct which connects the Neutral Beam Enclosure to the Torus. This bellows, located at the pivot point, must fit the severely limited space available at the pivot-point location. Consequently, it has to be made rectangular in cross section with a large inside area for beam access. This leads to small convolutions with high stress concentrations. The function of the bellows is to permit change in the angular positioning of the neutral beam line with respect to the Tokamak, to isolate the Neutral Beam Line from the deflection of the Torus during bake out, and to allow for all misalignments. Internally the bellows will have a vacuum along with such gases such as hydrogen or deuterium. Tests parameters are described

Duality between the Deconfined Quantum-Critical Point and the Bosonic Topological Transition

Directory of Open Access Journals (Sweden)

Yan Qi Qin

2017-09-01

Full Text Available Recently, significant progress has been made in (2+1-dimensional conformal field theories without supersymmetry. In particular, it was realized that different Lagrangians may be related by hidden dualities; i.e., seemingly different field theories may actually be identical in the infrared limit. Among all the proposed dualities, one has attracted particular interest in the field of strongly correlated quantum-matter systems: the one relating the easy-plane noncompact CP^{1} model (NCCP^{1} and noncompact quantum electrodynamics (QED with two flavors (N=2 of massless two-component Dirac fermions. The easy-plane NCCP^{1} model is the field theory of the putative deconfined quantum-critical point separating a planar (XY antiferromagnet and a dimerized (valence-bond solid ground state, while N=2 noncompact QED is the theory for the transition between a bosonic symmetry-protected topological phase and a trivial Mott insulator. In this work, we present strong numerical support for the proposed duality. We realize the N=2 noncompact QED at a critical point of an interacting fermion model on the bilayer honeycomb lattice and study it using determinant quantum Monte Carlo (QMC simulations. Using stochastic series expansion QMC simulations, we study a planar version of the S=1/2 J-Q spin Hamiltonian (a quantum XY model with additional multispin couplings and show that it hosts a continuous transition between the XY magnet and the valence-bond solid. The duality between the two systems, following from a mapping of their phase diagrams extending from their respective critical points, is supported by the good agreement between the critical exponents according to the proposed duality relationships. In the J-Q model, we find both continuous and first-order transitions, depending on the degree of planar anisotropy, with deconfined quantum criticality surviving only up to moderate strengths of the anisotropy. This explains previous claims of no deconfined

Ambient mass spectrometry: From the planar to the non-planar surface analysis

Czech Academy of Sciences Publication Activity Database

Rejšek, Jan; Vrkoslav, Vladimír; Cvačka, Josef

2017-01-01

Roč. 15, č. 1 (2017), s. 31 ISSN 2336-7202. [Mezioborové setkání mladých biologů, biochemiků a chemiků /17./. 30.05.2017-01.06.2017, Milovy] Institutional support: RVO:61388963 Keywords : ambient mass spectrometry * thin layer chromatography * non-planar surface analysis Subject RIV: CB - Analytical Chemistry, Separation

Molecular dynamics simulations of field emission from a planar nanodiode

Energy Technology Data Exchange (ETDEWEB)

Torfason, Kristinn; Valfells, Agust; Manolescu, Andrei [School of Science and Engineering, Reykjavik University, Menntavegur 1, IS-101 Reykjavik (Iceland)

2015-03-15

High resolution molecular dynamics simulations with full Coulomb interactions of electrons are used to investigate field emission in planar nanodiodes. The effects of space-charge and emitter radius are examined and compared to previous results concerning transition from Fowler-Nordheim to Child-Langmuir current [Y. Y. Lau, Y. Liu, and R. K. Parker, Phys. Plasmas 1, 2082 (1994) and Y. Feng and J. P. Verboncoeur, Phys. Plasmas 13, 073105 (2006)]. The Fowler-Nordheim law is used to determine the current density injected into the system and the Metropolis-Hastings algorithm to find a favourable point of emission on the emitter surface. A simple fluid like model is also developed and its results are in qualitative agreement with the simulations.

Analysis of kinematically redundant reaching movements using the equilibrium-point hypothesis.

Science.gov (United States)

Cesari, P; Shiratori, T; Olivato, P; Duarte, M

2001-03-01

Six subjects performed a planar reaching arm movement to a target while unpredictable perturbations were applied to the endpoint; the perturbations consisted of pulling springs having different stiffness. Two conditions were applied; in the first, subjects had to reach for the target despite the perturbation, in the second condition, the subjects were asked to not correct the motion as a perturbation was applied. We analyzed the kinematics profiles of the three arm segments and, by means of inverse dynamics, calculated the joint torques. The framework of the equilibrium-point (EP) hypothesis, the lambda model, allowed the reconstruction of the control variables, the "equilibrium trajectories", in the "do not correct" condition for the wrist and the elbow joints as well as for the end point final position, while for the other condition, the reconstruction was less reliable. The findings support and extend to a multiple-joint planar movement, the paradigm of the EP hypothesis along with the "do not correct" instruction.

Development of simulators algorithms of planar radioactive sources for use in computer models of exposure

International Nuclear Information System (INIS)

Vieira, Jose Wilson; Leal Neto, Viriato; Lima Filho, Jose de Melo; Lima, Fernando Roberto de Andrade

2013-01-01

This paper presents as algorithm of a planar and isotropic radioactive source and by rotating the probability density function (PDF) Gaussian standard subjected to a translatory method which displaces its maximum throughout its field changes its intensity and makes the dispersion around the mean right asymmetric. The algorithm was used to generate samples of photons emerging from a plane and reach a semicircle involving a phantom voxels. The PDF describing this problem is already known, but the generating function of random numbers (FRN) associated with it can not be deduced by direct MC techniques. This is a significant problem because it can be adjusted to simulations involving natural terrestrial radiation or accidents in medical establishments or industries where the radioactive material spreads in a plane. Some attempts to obtain a FRN for the PDF of the problem have already been implemented by the Research Group in Numerical Dosimetry (GND) from Recife-PE, Brazil, always using the technique rejection sampling MC. This article followed methodology of previous work, except on one point: The problem of the PDF was replaced by a normal PDF transferred. To perform dosimetric comparisons, we used two MCES: the MSTA (Mash standing, composed by the adult male voxel phantom in orthostatic position, MASH (male mesh), available from the Department of Nuclear Energy (DEN) of the Federal University of Pernambuco (UFPE), coupled to MC EGSnrc code and the GND planar source based on the rejection technique) and MSTA N T. The two MCES are similar in all but FRN used in planar source. The results presented and discussed in this paper establish the new algorithm for a planar source to be used by GND

SPECT versus planar bone radionuclide imaging in the detection of spondylolysis

International Nuclear Information System (INIS)

Whitten, C.G.; El-Khoury, G.Y.; Chang, P.J.; Seabold, J.E.; Found, E.M.; Renfrew, D.L.

1991-01-01

This paper evaluates the relative performance and ease of interpretation of SPECT versus planar radionuclide bone imaging in the detection of spondylolysis. The authors studied all patients presenting with back pain suggestive of spondylolysis from November 1989 to January 1991 who underwent bone scanning; patients underwent both planar and SPECT imaging. The planar and SPECT images were randomly mixed and independently interpreted by four observers for presence or absence of spondylolysis and ease of interpretation for each scan. Receiver operating characteristic (ROC) and analysis of variance (ANOVA) were used. Of 72 patients, 19 had confirmed spondylolysis, and 53 did not. While ROC analysis showed that SPECT performed slightly better than planar imaging for all four observers, the difference was not statistically significant. ANOVA results suggest that planar imaging was significantly easier to use than SPECT and that ease of use was strongly correlated with the observer's confidence in the diagnosis

Planar hydrodynamic instability computations and experiments with rugby-shaped hohlraums at the Omega laser

Energy Technology Data Exchange (ETDEWEB)

Vandenboomgaerde, M; Liberatore, S; Galmiche, D; Casner, A; Huser, G; Jadaud, J P; Villette, B [Commissariat a l' Energie Atomique, CEA/DAM-Ile de France, BP 12, 91680 Bruyeres-Le-Chatel (France)

2008-05-15

Implosion of inertial confinement fusion (ICF) capsule is very sensitive to the growth of sphericity perturbations. The control of the feeding of such perturbations and their transport ('feedthrough') through the ablator is a key point to reach ignition. Since 2002, experiments have been designed and performed on the Omega laser facility in order to study these phenomena in planar geometry. A new 'rugby shaped' hohlraum was used. We present experimental results and comparisons with numerical simulations.

Influence of presence of inclined centered baffle and corrugation frequency on natural convection heat transfer flow of air inside a square enclosure with corrugated side walls

Energy Technology Data Exchange (ETDEWEB)

Hussain, Salam Hadi; Jabbar, Mohammed Yousif; Mohamad, Ahmad Saddy [Mechanical Engineering Department, College of Engineering, Babylon University, Babylon Province (Iraq)

2011-09-15

The main objective of this study is to investigate the effect of presence of insulated inclined centered baffle and corrugation frequency on the steady natural convection in a sinusoidal corrugated enclosure. The present study is based on such a configuration where the two vertical sinusoidal walls are maintained at constant low temperature whereas a constant heat flux source whose length is 80% of the width of the enclosure is discretely embedded in the bottom wall. The remaining parts of the bottom wall and the top wall are adiabatic. The finite volume method has been used to solve the governing Navier-Stokes and the energy conservation equations of the fluid medium in the enclosure in order to investigate the effects of baffle inclination angles, corrugation frequencies and Grashof numbers on the fluid flow and heat transfer in the enclosure. The values of the governing parameters are the Grashof number Gr (10{sup 3}-10{sup 6}), the corrugation frequencies CF (1, 2 and 3), baffle inclination angles (0 deg. {<=} {phi} {<=} 150 deg.) and Prandtl number Pr (0.71). Results are presented in the form of streamline and isotherm plots. The results of this investigation are illustrated that the average Nusselt number increases with increase in both the Grashof number and corrugation frequency for different baffle inclination angles and the presence of inclined baffle and increasing the corrugation frequency have significant effects on the average Nusselt numbers, streamlines and isotherms inside the enclosure. The obtained numerical results have been compared with literature ones, and it gives a reliable agreement. (authors)

Effective diffusion in time-periodic linear planar flow

International Nuclear Information System (INIS)

Indeikina, A.; Chang, H.

1993-01-01

It is shown that when a point source of solute is inserted into a time-periodic, unbounded linear planar flow, the large-time, time-average transport of the solute can be described by classical anisotropic diffusion with constant effective diffusion tensors. For a given vorticity and forcing period, elongational flow is shown to be the most dispersive followed by simple shear and rotational flow. Large-time diffusivity along the major axis of the time-average concentration ellipse, whose alignment is predicted from the theory, is shown to increase with vorticity for all flows and decrease with increasing forcing frequency for elongational flow and simple shear. For the interesting case of rotational flow, there exist discrete resonant frequencies where the time-average major diffusivity reaches local maxima equal to the time-average steady flow case with zero forcing frequency

Spectrum of classes of point emitters of electromagnetic wave fields.

Science.gov (United States)

Castañeda, Román

2016-09-01

The spectrum of classes of point emitters has been introduced as a numerical tool suitable for the design, analysis, and synthesis of non-paraxial optical fields in arbitrary states of spatial coherence. In this paper, the polarization state of planar electromagnetic wave fields is included in the spectrum of classes, thus increasing its modeling capabilities. In this context, optical processing is realized as a filtering on the spectrum of classes of point emitters, performed by the complex degree of spatial coherence and the two-point correlation of polarization, which could be implemented dynamically by using programmable optical devices.

Vibration measurements of the Daniel K. Inouye Solar Telescope mount, Coudé rotator, and enclosure assemblies

Science.gov (United States)

McBride, William R.; McBride, Daniel R.

2016-08-01

The Daniel K. Inouye Solar Telescope (DKIST) will be the largest solar telescope in the world, with a 4-meter off-axis primary mirror and 16 meter rotating Coudé laboratory within the telescope pier. The off-axis design requires a mount similar to an 8-meter on-axis telescope. Both the telescope mount and the Coudé laboratory utilize a roller bearing technology in place of the more commonly used hydrostatic bearings. The telescope enclosure utilizes a crawler mechanism for the altitude axis. As these mechanisms have not previously been used in a telescope, understanding the vibration characteristics and the potential impact on the telescope image is important. This paper presents the methodology used to perform jitter measurements of the enclosure and the mount bearings and servo system in a high-noise environment utilizing seismic accelerometers and high dynamic-range data acquisition equipment, along with digital signal processing (DSP) techniques. Data acquisition and signal processing were implemented in MATLAB. In the factory acceptance testing of the telescope mount, multiple accelerometers were strategically located to capture the six axes-of-motion of the primary and secondary mirror dummies. The optical sensitivity analysis was used to map these mirror mount displacements and rotations into units of image motion on the focal plane. Similarly, tests were done with the Coudé rotator, treating the entire rotating instrument lab as a rigid body. Testing was performed by recording accelerometer data while the telescope control system performed tracking operations typical of various observing scenarios. The analysis of the accelerometer data utilized noise-averaging fast Fourier transform (FFT) routines, spectrograms, and periodograms. To achieve adequate dynamic range at frequencies as low as 3Hz, the use of special filters and advanced windowing functions were necessary. Numerous identical automated tests were compared to identify and select the data sets

Moisture ingress into electronics enclosures under isothermal conditions

International Nuclear Information System (INIS)

Staliulionis, Ž.; Jabbari, M.; Hattel, J. H.

2016-01-01

The number of electronics used in outdoor environment is constantly growing. The humidity causes about 19 % of all electronics failures and, especially, moisture increases these problems due to the ongoing process of miniaturization and lower power consumption of electronic components. Moisture loads are still not understood well by design engineers, therefore this field has become one of the bottlenecks in the electronics system design. The objective of this paper is to model moisture ingress into an electronics enclosure under isothermal conditions. The moisture diffusion model is based on a 1D quasi-steady state (QSS) approximation for Fick’s second law. This QSS approach is also described with an electrical analogy which gives a fast tool in modelling of the moisture response. The same QSS method is applied to ambient water vapour variations. The obtained results are compared to an analytical solution and very good agreement is found.

The value of filtered planar images in pediatric DMSA scans

International Nuclear Information System (INIS)

Mohammed, A.M.; Naddaf, S.Y.; Elgazzar, A.H.; Al-Abdul Salam, A.A.; Omar, A.A.

2006-01-01

The study was designed to demonstrate the value of filtered planar images in paediatric DMSA scanning. One hundred and seventy three patients ranged in age from 15 days to 12 years (mean: 4.3 years) with urinary tract infection (UTI) and clinical and/or laboratory suspicion of acute pyelonephritis (APN) were retrospectively studied. Planar images were filtered using Butterworth filter. The scan findings were reported as positive, negative or equivocal for cortical defects. Each scan was read in a double-blind fashion by two nuclear medicine physicians to evaluate inter-observer variations. Each kidney was divided into three zones, upper, middle and lower, and each zone was graded as positive, negative or equivocal for the presence of renal defects. Renal cortical defects were found in 66 patients (91 kidneys and 186 zones) with filtered images, 58 patients (81 kidneys and 175 zones) with planar images, and 69 patients (87 kidneys and 180 zones) with SPECT images. McNemar's test revealed statistically significant difference between filtered and planar images (p=0.038 for patients, 0.021 for kidneys and 0.034 for number of zones). Inter-observer agreement was 0.877 for filtered images, 0.915 for planar images and 0.915 for SPECT images. It was concluded that filtered planar images of renal cortex are comparable to SPECT images and can be used effectively in place of SPECT, when required, to shorten imaging time and eliminate motion artifacts, especially in the paediatric population. (author)

Modeling and analysis of a novel planar eddy current damper

Science.gov (United States)

Zhang, He; Kou, Baoquan; Jin, Yinxi; Zhang, Lu; Zhang, Hailin; Li, Liyi

2014-05-01

In this paper, a novel 2-DOF permanent magnet planar eddy current damper is proposed, of which the stator is made of a copper plate and the mover is composed of two orthogonal 1-D permanent magnet arrays with a double sided structure. The main objective of the planar eddy current damper is to provide two orthogonal damping forces for dynamic systems like the 2-DOF high precision positioning system. Firstly, the basic structure and the operating principle of the planar damper are introduced. Secondly, the analytical model of the planar damper is established where the magnetic flux density distribution of the permanent magnet arrays is obtained by using the equivalent magnetic charge method and the image method. Then, the analytical expressions of the damping force and damping coefficient are derived. Lastly, to verify the analytical model, the finite element method (FEM) is adopted for calculating the flux density and a planar damper prototype is manufactured and thoroughly tested. The results from FEM and experiments are in good agreement with the ones from the analytical expressions indicating that the analytical model is reasonable and correct.

Dynamical analysis of surface-insulated planar wire array Z-pinches

Science.gov (United States)

Li, Yang; Sheng, Liang; Hei, Dongwei; Li, Xingwen; Zhang, Jinhai; Li, Mo; Qiu, Aici

2018-05-01

The ablation and implosion dynamics of planar wire array Z-pinches with and without surface insulation are compared and discussed in this paper. This paper first presents a phenomenological model named the ablation and cascade snowplow implosion (ACSI) model, which accounts for the ablation and implosion phases of a planar wire array Z-pinch in a single simulation. The comparison between experimental data and simulation results shows that the ACSI model could give a fairly good description about the dynamical characteristics of planar wire array Z-pinches. Surface insulation introduces notable differences in the ablation phase of planar wire array Z-pinches. The ablation phase is divided into two stages: insulation layer ablation and tungsten wire ablation. The two-stage ablation process of insulated wires is simulated in the ACSI model by updating the formulas describing the ablation process.

Anisotropic Magnus Force in Type-II Superconductors with Planar Defects

Science.gov (United States)

Monroy, Ricardo Vega; Gomez, Eliceo Cortés

2015-02-01

The effect of planar defects on the Magnus force in type-II superconductors is studied. It is shown that the deformation of the vortex due to the presence of a planar defect leads to a local decrease in the mean free path of electrons in the vortex. This effect reduces the effective Magnus coefficient in normal direction to the planar defect, leading to an anisotropic regime of the Hall effect. The presented developments here can qualitatively explain experimental observations of the anisotropic Hall effect in high- T c superconductors in the mixed state.

Spacing and enclosure assembly for a reflecting thermal isolation panel

International Nuclear Information System (INIS)

Murdock, B.R.

1979-01-01

This invention concerns the thermal insulation assemblies and in particular a metallic assembly of stays and enclosures for a reflecting type panel used for insulation in nuclear reactors. Great flexibility is achieved by a corrugated strip placed edgewise around all the first reflecting insulating sheet. A second reflecting insulating sheet is then superposed on this corrugated strip which acts as a thickness spacer along the periphery of both sheets and also hermetically closes the intermediate space. The corrugations of the edge strip allow both sheets to be curved lengthwise or crosswise without causing their spacing to vary. These corrugations simply open like the pleats of an accordeon or a fan to fit the curve of the greatest radius [fr

HP Ge planar detectors

International Nuclear Information System (INIS)

Gornov, M.G.; Gurov, Yu.B.; Soldatov, A.M.; Osipenko, B.P.; Yurkowski, J.; Podkopaev, O.I.

1989-01-01

Parameters of planar detectors manufactured of HP Ge are presented. The possibilities to use multilayer spectrometers on the base of such semiconductor detectors for nuclear physics experiments are discussed. It is shown that the obtained detectors including high square ones have spectrometrical characteristics close to limiting possible values. 9 refs.; 3 figs.; 1 tab

Slices: A shape-proxy based on planar sections

KAUST Repository

McCrae, James

2011-12-01

Minimalist object representations or shape-proxies that spark and inspire human perception of shape remain an incompletely understood, yet powerful aspect of visual communication. We explore the use of planar sections, i.e., the contours of intersection of planes with a 3D object, for creating shape abstractions, motivated by their popularity in art and engineering. We first perform a user study to show that humans do define consistent and similar planar section proxies for common objects. Interestingly, we observe a strong correlation between user-defined planes and geometric features of objects. Further we show that the problem of finding the minimum set of planes that capture a set of 3D geometric shape features is both NP-hard and not always the proxy a user would pick. Guided by the principles inferred from our user study, we present an algorithm that progressively selects planes to maximize feature coverage, which in turn influence the selection of subsequent planes. The algorithmic framework easily incorporates various shape features, while their relative importance values are computed and validated from the user study data. We use our algorithm to compute planar slices for various objects, validate their utility towards object abstraction using a second user study, and conclude showing the potential applications of the extracted planar slice shape proxies.

Quasi-planar elemental clusters in pair interactions approximation

Directory of Open Access Journals (Sweden)

Chkhartishvili Levan

2016-01-01

Full Text Available The pair-interactions approximation, when applied to describe elemental clusters, only takes into account bonding between neighboring atoms. According to this approach, isomers of wrapped forms of 2D clusters – nanotubular and fullerene-like structures – and truly 3D clusters, are generally expected to be more stable than their quasi-planar counterparts. This is because quasi-planar clusters contain more peripheral atoms with dangling bonds and, correspondingly, fewer atoms with saturated bonds. However, the differences in coordination numbers between central and peripheral atoms lead to the polarization of bonds. The related corrections to the molar binding energy can make small, quasi-planar clusters more stable than their 2D wrapped allotropes and 3D isomers. The present work provides a general theoretical frame for studying the relative stability of small elemental clusters within the pair interactions approximation.

Application of holographic elements in displays and planar illuminators

Science.gov (United States)

Putilin, Andrew; Gustomiasov, Igor

2007-05-01

Holographic Optical Elements (HOE's) on planar waveguides can be used to design the planar optics for backlit units, color selectors or filters, lenses for virtual reality displays. The several schemes for HOE recording are proposed to obtain planar stereo backlit unit and private eye displays light source. It is shown in the paper that the specific light transformation grating permits to construct efficient backlit units for display holograms and LCD. Several schemes of reflection/transmission backlit units and scattering films based on holographic optical elements are also proposed. The performance of the waveguide HOE can be optimized using the parameters of recording scheme and etching parameters. The schemes of HOE application are discussed and some experimental results are shown.

A DGTD Scheme for Modeling the Radiated Emission From DUTs in Shielding Enclosures Using Near Electric Field Only

KAUST Repository

Li, Ping; Shi, Yifei; Jiang, Li Jun; Bagci, Hakan

2016-01-01

, in this paper, a novel approach is proposed to model the radiated emission from electronic devices placed in shielding enclosures by using the near electric field only. Based on the Schelkkunoff’s equivalence principle and Raleigh–Carson reciprocity theorem

Group theoretical construction of planar noncommutative phase spaces

Energy Technology Data Exchange (ETDEWEB)

Ngendakumana, Ancille, E-mail: nancille@yahoo.fr; Todjihoundé, Leonard, E-mail: leonardt@imsp.uac.org [Institut de Mathématiques et des Sciences Physiques (IMSP), Porto-Novo (Benin); Nzotungicimpaye, Joachim, E-mail: kimpaye@kie.ac.rw [Kigali Institute of Education (KIE), Kigali (Rwanda)

2014-01-15

Noncommutative phase spaces are generated and classified in the framework of centrally extended anisotropic planar kinematical Lie groups as well as in the framework of noncentrally abelian extended planar absolute time Lie groups. Through these constructions the coordinates of the phase spaces do not commute due to the presence of naturally introduced fields giving rise to minimal couplings. By symplectic realizations methods, physical interpretations of generators coming from the obtained structures are given.

Group theoretical construction of planar noncommutative phase spaces

International Nuclear Information System (INIS)

Ngendakumana, Ancille; Todjihoundé, Leonard; Nzotungicimpaye, Joachim

2014-01-01

Noncommutative phase spaces are generated and classified in the framework of centrally extended anisotropic planar kinematical Lie groups as well as in the framework of noncentrally abelian extended planar absolute time Lie groups. Through these constructions the coordinates of the phase spaces do not commute due to the presence of naturally introduced fields giving rise to minimal couplings. By symplectic realizations methods, physical interpretations of generators coming from the obtained structures are given

Effects of wind turbines on area use and behaviour of semi-domestic reindeer in enclosures

Directory of Open Access Journals (Sweden)

Kjetil Flydal

2004-04-01

Full Text Available In recent decades, industrial developments have expanded into reindeer ranges in the arctic and adjacent higher latitudes in search for energy, minerals, timber and other resources. Several wind turbine parks are under planning in reindeer ranges in Norway, and there is concern about possible negative effects on behaviour and area use of wild and semi-domestic reindeer. We tested whether a wind turbine and its rotor movement had any effect on area use, activity changes, vigilance bouts, and restless behaviour like running, walking, and standing for enclosed semi-domestic reindeer. Five different groups of reindeer in a 450 m long, 8 hectare, enclosure close to a wind turbine were manipulated by turning the wind turbine rotor on and off, and compared with reindeer in a control enclosure without wind turbine exposure. When exposed to rotor movement, two groups used locations farther from the wind turbine, two groups showed no shift, while one group moved closer to the wind turbine. The reindeer showed no systematic differences in the measured behaviour patterns between the two enclosures that could indicate fright or stress as a consequence of the wind turbine or rotor movement. We conclude that semi-domestic reindeer in an enclosure showed no negative behavioural response and little or no aversion towards a wind turbine. The possibility of rapid habituation in a small enclosure with continuous wind turbine exposure suggests that effects on area use should be studied at a larger scale or with free-ranging reindeer.Abstract in Norwegian / Sammendrag:I løpet av de senere tiår har industriell utbygging til utnytting av energi, mineraler, tømmer og andre ressurser ekspandert inn i reinens beiteområder i nordområdene. Flere vindmølleparker er under planlegging i norske reinbeiteområder, og det spekuleres i mulige konsekvenser av disse på atferd og arealbruk hos villrein og tamrein. Vi testet om en vindmølle og dens rotorbevegelse hadde noen

Miniaturized Air-Driven Planar Magnetic Generators

Directory of Open Access Journals (Sweden)

Jingjing Zhao

2015-10-01

Full Text Available This paper presents the design, analysis, fabrication and testing of two miniaturized air-driven planar magnetic generators. In order to reduce the magnetic resistance torque, Generator 1 establishes a static magnetic field by consisting a multilayer planar coil as the stator and two multi-pole permanent-magnet (PM rotors on both sides of the coil. To further decrease the starting torque and save more space, Generator 2 adopts the multilayer planar coil as the rotor and the multi-pole PMs as the stator, eliminating the casing without compromising the magnetic structure or output performance. The prototypes were tested gathering energy from wind which can work at a low wind speed of 1~2 m/s. Prototype of Generator 1 is with a volume of 2.61 cm3 and its normalized voltage reaches 485 mV/krpm. Prototype of Generator 2 has a volume of 0.92 cm3 and a normalized voltage as high as 538 mV/krpm. Additionally, output voltage can be estimated at better than 96% accuracy by the theoretical model developed in this paper. The two micro generators are capable of producing substantial electricity with little volume to serve as compact power conversion devices.

Routed planar networks

Directory of Open Access Journals (Sweden)

David J. Aldous

2016-04-01

Full Text Available Modeling a road network as a planar graph seems very natural. However, in studying continuum limits of such networks it is useful to take {\\em routes} rather than {\\em edges} as primitives. This article is intended to introduce the relevant (discrete setting notion of {\\em routed network} to graph theorists. We give a naive classification of all 71 topologically different such networks on 4 leaves, and pose a variety of challenging research questions.

Pointing control for LDR

Science.gov (United States)

Yam, Y.; Briggs, C.

1988-01-01

One important aspect of the LDR control problem is the possible excitations of structural modes due to random disturbances, mirror chopping, and slewing maneuvers. An analysis was performed to yield a first order estimate of the effects of such dynamic excitations. The analysis involved a study of slewing jitters, chopping jitters, disturbance responses, and pointing errors, making use of a simplified planar LDR model which describes the LDR dynamics on a plane perpendicular to the primary reflector. Briefly, the results indicate that the command slewing profile plays an important role in minimizing the resultant jitter, even to a level acceptable without any control action. An optimal profile should therefore be studied.

Analysis and Synthesis of Leaky-Wave Devices in Planar Technology

Science.gov (United States)

Martinez Ros, Alejandro Javier

The work developed along this doctoral thesis has been focused on the analysis and synthesis of microwave devices in planar technology. In particular, several types of devices based on the radiation mechanism of leaky waves have been studied. Typically, the radiation properties in leaky-wave devices are determined by the complex propagation constant of the leaky mode, wherein the phase constant is responsible for the pointing angle and the leakage rate for the intensity of the radiated fields. In this manner, by controlling both amplitude and phase of the leaky mode, an effective control over the device's radiation diagram can be obtained. Moreover, with the purpose of efficiently obtaining the leaky mode's radiation properties as function of the main geometrical parameters of the structure, several modal tools based on the transverse resonance analysis of the structure have been performed. In order to demonstrate this simultaneous control over the complex propagation constant in planar technology, several types of leaky-wave devices, including antennas (LWAs), multiplexors and near-field focusing systems, have been designed and manufactured in the technology of substrate integrated waveguide (SIW). This recently proposed technology, allows the design of devices based on classical waveguide technology with standard manufacturing techniques used for printed circuit board (PCB) designs. In this way, most of the parts that form a communication system can be integrated into a single substrate, thus reducing its cost and providing a more robust and compact device, which has less losses compared to other planar technologies such as the microstrip. El trabajo llevado a cabo durante la realizacion de esta tesis doctoral, se ha centrado en el analisis y sintesis de dispositivos de microondas en tecnologia planar. En concreto, se han estudiado diferentes tipos de dispositivos basados en radiacion por ondas de fuga "leaky waves", en los cuales las propiedades de radiacion

Buoyancy and thermocapillary driven convection flow of electrically conducting fluid in an enclosure with heat generation

International Nuclear Information System (INIS)

Hossain, Md. Anwar; Rees, D.A.S.

2002-05-01

The effect of surface tension on unsteady laminar natural convection flow of a viscous incompressible fluid in a rectangle enclosure with internal heat generation and in presence of a uniform transverse magnetic field acting in the direction normal to the gravity has been investigated. The top horizontal surface of the rectangular cavity is assumed to be free and the bottom ones insulated; whereas the left vertical wall is cold and the right one is uniformly hot. The equations are non-dimensionalized and solved numerically by an upwind finite difference method together with a successive over-relaxation (SOR) technique. The effects of heat generation together with the combined effects of the magnetic field and the surface tension are presented graphically in terms of isotherms, streamlines and velocity vector plots. The effects of varying the physical parameters on the rate of heat transfer from the heated surface of the enclosure are also depicted. The fluid here has Prandtl number Pr=0.054 while the value of the Grashof number is 2x10 4 . (author)

Planar waveguide laser in Er/Al-doped germanosilicate

DEFF Research Database (Denmark)

Guldberg-Kjær, Søren Andreas; Hübner, Jörg; Kristensen, Martin

1999-01-01

A singlemode DBR laser is demonstrated in an Er/Al-doped germanosilicate planar waveguide. 0.4 mW of output power has been obtained at 1.553 mu m using internal Bragg reflectors produced by UV-induced index modulations.......A singlemode DBR laser is demonstrated in an Er/Al-doped germanosilicate planar waveguide. 0.4 mW of output power has been obtained at 1.553 mu m using internal Bragg reflectors produced by UV-induced index modulations....

Mating competitiveness of Aedes albopictus radio-sterilized males in large enclosures exposed to natural conditions.

Science.gov (United States)

Bellini, R; Balestrino, F; Medici, A; Gentile, G; Veronesi, R; Carrieri, M

2013-01-01

Mating competitiveness trials have been conducted in large net-screened enclosures (8 by 5 by 2.8 m) built in a natural shaded environment, in the summers of 2006, 2007, 2008, and 2009 in northern Italy. Aedes albopictus (Skuse) males were radio-sterilized by applying gamma radiations at doses in the range 30-60 Gy. Gamma radiation was administered to aged pupae at the rate of 2.3 Gy/min. Reared radiated males (originally collected in Rimini, Forli, Bologna, Matera, Pinerolo) and hybrid radiated males were tested against wild fertile males (originated from eggs collected in Rimini and Cesena) and reared fertile males, in multiple comparisons for mating competitiveness with reared or wild females. The ratio was kept constant at 100-100_100 (fertile males-radiated males_virgin females). Mating competitiveness was estimated through the calculation of the hatching rate of the eggs laid in oviposition traps positioned inside enclosures. No clear effect of the strains tested (reared, wild, or hybrid) was found. Results demonstrated that reducing the radiation dose from 60 to 30 Gy increases males' competitiveness. Laboratory investigations conducted after controversial results in the 2006 preliminary trials, showed that radiation induces precociousness in adult male emergence.

Natural convection in square enclosure induced by inner circular cylinder with time-periodic pulsating temperature

KAUST Repository

Huang, Zhu

2015-03-01

The periodic unsteady natural convection flow and heat transfer in a square enclosure containing a concentric circular cylinder is numerically studied. The temperature of the inner circular cylinder fluctuates periodically with time at higher averaged value while the temperature of the enclosure keeps lower constant, and the natural convection is driven by the temperature difference. The two-dimensional natural convection is simulated with high accuracy temporal spectral method and local radial basis functions method. The Rayleigh number is studied in the range 103 ≤ Ra ≤ 106, the temperature pulsating period ranges from 0.01 to 100 and the temperature pulsating amplitudes are a = 0.5, 1.0 and 1.5. Numerical results reveal that the fluid flow and heat transfer is strongly dependent on the pulsating temperature of inner cylinder. Comparing with the steady state natural convection, the heat transfer is enhanced generally for the time-periodic unsteady natural convection, and the local maximum heat transfer rate is observed for Ra = 105 and 106. Moreover, the phenomenon of backward heat transfer is discussed quantitatively. Also, the influence of pulsating temperature on the unsteady fluid flow and heat transfer are discussed and analyzed.

Numerical simulation of double-diffusive mixed convective flow in rectangular enclosure with insulated moving lid

Energy Technology Data Exchange (ETDEWEB)

Teamah, M.A. [Faculty of Engineering, Alexandria University, Mech. Eng. Dept, Alexandria (Egypt); El-Maghlany, W.M. [Faculty of Engineering, Suez Canal University, Ismailia (Egypt)

2010-09-15

The present study is concerned with the mixed convection in a rectangular lid-driven cavity under the combined buoyancy effects of thermal and mass diffusion. Double-diffusive convective flow in a rectangular enclosure with moving upper surface is studied numerically. Both upper and lower surfaces are being insulated and impermeable. Constant different temperatures and concentration are imposed along the vertical walls of the enclosure, steady state laminar regime is considered. The transport equations for continuity, momentum, energy and spices transfer are solved. The numerical results are reported for the effect of Richardson number, Lewis number, and buoyancy ratio on the iso-contours of stream line, temperature, and concentration. In addition, the predicted results for both local and average Nusselt and Sherwood numbers are presented and discussed for various parametric conditions. This study was done for 0.1 <= Le <= 50 and Prandtl number Pr = 0.7. Through out the study the Grashof number and aspect ratio are kept constant at 10{sup 4} and 2 respectively and -10 <= N <= 10, while Richardson number has been varied from 0.01 to 10 to simulate forced convection dominated flow, mixed convection and natural convection dominated flow. (authors)

Planar channeling in superlattices: Theory

International Nuclear Information System (INIS)

Ellison, J.A.; Picraux, S.T.; Allen, W.R.; Chu, W.K.

1988-01-01

The well-known continuum model theory for planar channeled energetic particles in perfect crystals is extended to layered crystalline structures and applied to superlattices. In a strained-layer structure, the planar channels with normals which are not perpendicular to the growth direction change their direction at each interface, and this dramatically influences the channeling behavior. The governing equation of motion for a planar channeled ion in a strained-layer superlattice with equal layer thicknesses is a one degree of freedom nonlinear oscillator which is periodically forced with a sequence of δ functions. These δ functions, which are of equal spacing and amplitude with alternating sign, represent the tilts at each of the interfaces. Thus upon matching an effective channeled particle wavelength, corresponding to a natural period of the nonlinear oscillator, to the period of the strained-layer superlattice, corresponding to the periodic forcing, strong resonance effects are expected. The condition of one effective wavelength per period corresponds to a rapid dechanneling at a well-defined depth (catastrophic dechanneling), whereas two wavelengths per period corresponds to no enhanced dechanneling after the first one or two layers (resonance channeling). A phase plane analysis is used to characterize the channeled particle motion. Detailed calculations using the Moliere continuum potential are compared with our previously described modified harmonic model, and new results are presented for the phase plane evolution, as well as the dechanneling as a function of depth, incident angle, energy, and layer thickness. General scaling laws are developed and nearly universal curves are obtained for the dechanneling versus depth under catastrophic dechanneling

Parallel-fed planar dipole antenna arrays for low-observable platforms

CERN Document Server

Singh, Hema; Jha, Rakesh Mohan

2016-01-01

This book focuses on determination of scattering of parallel-fed planar dipole arrays in terms of reflection and transmission coefficients at different levels of the array system. In aerospace vehicles, the phased arrays are often in planar configuration. The radar cross section (RCS) of the vehicle is mainly due to its structure and the antennas mounted over it. There can be situation when the signatures due to antennas dominate over the structural RCS of the platform. This necessitates the study towards the reduction and control of antenna/ array RCS. The planar dipole array is considered as a stacked linear dipole array. A systematic, step-by-step approach is used to determine the RCS pattern including the finite dimensions of dipole antenna elements. The mutual impedance between the dipole elements for planar configuration is determined. The scattering till second-level of couplers in parallel feed network is taken into account. The phase shifters are modelled as delay line. All the couplers in the feed n...

A Trial of Natural Habitat Enclosure Traps as a Sampling Tool for Juvenile Crayfish

OpenAIRE

Fjälling, Arne; Engdahl, Fredrik; Edsman, Lennart; Bohman, Patrik; Sandström, Alfred

2013-01-01

Recruitment is a vital factor in the assessment, management and population dynamics of decapods. Since the juvenile stages of crayfish often prefer heterogeneous habitats, sampling with quantitative and reproducible methods have so far been challenging. We evaluate a new quantitative sampling method for juvenile crayfish; the enclosure trap. A field test was carried out during two consecutive years on a population of signal crayfish, Pacifastacus leniusculus, in littoral areas of Swedish Lake...

A planar microfluidic mixer based on logarithmic spirals

International Nuclear Information System (INIS)

Scherr, Thomas; Nandakumar, Krishnaswamy; Quitadamo, Christian; Tesvich, Preston; Park, Daniel Sang-Won; Hayes, Daniel; Monroe, W Todd; Tiersch, Terrence; Choi, Jin-Woo

2012-01-01

A passive, planar micromixer design based on logarithmic spirals is presented. The device was fabricated using polydimethylsiloxane soft photolithography techniques, and mixing performance was characterized via numerical simulation and fluorescent microscopy. Mixing efficiency initially declined as the Reynolds number increased, and this trend continued until a Reynolds number of 15 where a minimum was reached at 53%. Mixing efficiency then began to increase reaching a maximum mixing efficiency of 86% at Re = 67. Three-dimensional (3D) simulations of fluid mixing in this design were compared to other planar geometries such as the Archimedes spiral and Meandering-S mixers. The implementation of logarithmic curvature offers several unique advantages that enhance mixing, namely a variable cross-sectional area and a logarithmically varying radius of curvature that creates 3D Dean vortices. These flow phenomena were observed in simulations with multilayered fluid folding and validated with confocal microscopy. This design provides improved mixing performance over a broader range of Reynolds numbers than other reported planar mixers, all while avoiding external force fields, more complicated fabrication processes and the introduction of flow obstructions or cavities that may unintentionally affect sensitive or particulate-containing samples. Due to the planar design requiring only single-step lithographic features, this compact geometry could be easily implemented into existing micro-total analysis systems requiring effective rapid mixing. (paper)

Planar undulator motion excited by a fixed traveling wave. Quasiperiodic averaging normal forms and the FEL pendulum

Energy Technology Data Exchange (ETDEWEB)

Ellison, James A.; Heinemann, Klaus [New Mexico Univ., Albuquerque, NM (United States). Dept. of Mathematics and Statistics; Vogt, Mathias [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Gooden, Matthew [North Carolina State Univ., Raleigh, NC (United States). Dept. of Physics

2013-03-15

We present a mathematical analysis of planar motion of energetic electrons moving through a planar dipole undulator, excited by a fixed planar polarized plane wave Maxwell field in the X-Ray FEL regime. Our starting point is the 6D Lorentz system, which allows planar motions, and we examine this dynamical system as the wave length {lambda} of the traveling wave varies. By scalings and transformations the 6D system is reduced, without approximation, to a 2D system in a form for a rigorous asymptotic analysis using the Method of Averaging (MoA), a long time perturbation theory. The two dependent variables are a scaled energy deviation and a generalization of the so- called ponderomotive phase. As {lambda} varies the system passes through resonant and nonresonant (NR) zones and we develop NR and near-to-resonant (NtoR) MoA normal form approximations. The NtoR normal forms contain a parameter which measures the distance from a resonance. For a special initial condition, for the planar motion and on resonance, the NtoR normal form reduces to the well known FEL pendulum system. We then state and prove NR and NtoR first-order averaging theorems which give explicit error bounds for the normal form approximations. We prove the theorems in great detail, giving the interested reader a tutorial on mathematically rigorous perturbation theory in a context where the proofs are easily understood. The proofs are novel in that they do not use a near identity transformation and they use a system of differential inequalities. The NR case is an example of quasiperiodic averaging where the small divisor problem enters in the simplest possible way. To our knowledge the planar prob- lem has not been analyzed with the generality we aspire to here nor has the standard FEL pendulum system been derived with associated error bounds as we do here. We briefly discuss the low gain theory in light of our NtoR normal form. Our mathematical treatment of the noncollective FEL beam dynamics problem in

Planar undulator motion excited by a fixed traveling wave. Quasiperiodic averaging normal forms and the FEL pendulum

International Nuclear Information System (INIS)

Ellison, James A.; Heinemann, Klaus; Gooden, Matthew

2013-03-01

We present a mathematical analysis of planar motion of energetic electrons moving through a planar dipole undulator, excited by a fixed planar polarized plane wave Maxwell field in the X-Ray FEL regime. Our starting point is the 6D Lorentz system, which allows planar motions, and we examine this dynamical system as the wave length λ of the traveling wave varies. By scalings and transformations the 6D system is reduced, without approximation, to a 2D system in a form for a rigorous asymptotic analysis using the Method of Averaging (MoA), a long time perturbation theory. The two dependent variables are a scaled energy deviation and a generalization of the so- called ponderomotive phase. As λ varies the system passes through resonant and nonresonant (NR) zones and we develop NR and near-to-resonant (NtoR) MoA normal form approximations. The NtoR normal forms contain a parameter which measures the distance from a resonance. For a special initial condition, for the planar motion and on resonance, the NtoR normal form reduces to the well known FEL pendulum system. We then state and prove NR and NtoR first-order averaging theorems which give explicit error bounds for the normal form approximations. We prove the theorems in great detail, giving the interested reader a tutorial on mathematically rigorous perturbation theory in a context where the proofs are easily understood. The proofs are novel in that they do not use a near identity transformation and they use a system of differential inequalities. The NR case is an example of quasiperiodic averaging where the small divisor problem enters in the simplest possible way. To our knowledge the planar prob- lem has not been analyzed with the generality we aspire to here nor has the standard FEL pendulum system been derived with associated error bounds as we do here. We briefly discuss the low gain theory in light of our NtoR normal form. Our mathematical treatment of the noncollective FEL beam dynamics problem in the

Optical absorption in planar graphene superlattice: The role of structural parameters

Science.gov (United States)

Azadi, L.; Shojaei, S.

2018-04-01

We theoretically studied the optically driven interband transitions in a planar graphene superlattices (PGSL) formed by patterning graphene sheet on laterally hetrostructured substrate as Sio2/hBN. A tunable optical transitions between minibands is observed based on engineering structural parameters. We derive analytically expression for optical absorption from two-band model. Considerable optical absorption is obtained for different ratios between widths of heterostructured substrate and is explained analytically from the view point of wavefunction engineering and miniband dispersion, in details. The role of different statuses of polarization as circular and linear are considered. Our study paves a way toward the control of optical properties of PGSLs to be implemented in optoelectronics devices.

Nb multilayer planarization technology for a subnanosecond Josephson 1K-bit RAM

International Nuclear Information System (INIS)

Nagasawa, S.; Wada, Y.; Tsuge, H.; Hidaka, M.; Ishida, I.; Tahara, S.

1989-01-01

Nb multilayer planarization technology has been developed. This planarization technology consists of an etch-back technique using 2000-molecular weight polystyrene and SiO/sub 2/ for the junction layer and wiring layers, and a tapered edge etching technique for contact between individual wiring layers. A Josephson 1K-bit random access memory (RAM) has been fabricated using this planarization technology. Excellent planarity, wherein level differences in all step areas are reduced to less than 1/20th of their original value, was achieved in the multilayer structure of the RAM. Moreover, appropriate RAM operations, with 570ps minimum access time and 13mW power dissipation, were confirmed

A DGTD Scheme for Modeling the Radiated Emission From DUTs in Shielding Enclosures Using Near Electric Field Only

KAUST Repository

Li, Ping

2016-01-13

To meet the electromagnetic interference regulation, the radiated emission from device under test such as electronic devices must be carefully manipulated and accurately characterized. Instead of resorting to the direct far-field measurement, in this paper, a novel approach is proposed to model the radiated emission from electronic devices placed in shielding enclosures by using the near electric field only. Based on the Schelkkunoff’s equivalence principle and Raleigh–Carson reciprocity theorem, only the tangential components of the electric field over the ventilation slots and apertures of the shielding enclosure are sufficient to obtain the radiated emissions outside the shielding box if the inside of the shielding enclosure was filled with perfectly electric conductor (PEC). In order to efficiently model wideband emission, the time-domain sampling scheme is employed. Due to the lack of analytical Green’s function for arbitrary PEC boxes, the radiated emission must be obtained via the full-wave numerical methods by considering the total radiated emission as the superposition between the direct radiation from the equivalent magnetic currents in free space and the scattered field generated by the PEC shielding box. In this study, the state-of-the-art discontinuous Galerkin time-domain (DGTD) method is utilized, which has the flexibility to model irregular geometries, keep high-order accuracy, and more importantly involves only local operations. For open-region problems, a hybridized DGTD and time-domain boundary integration method applied to rigorously truncate the computational domain. To validate the proposed approach, several representative examples are presented and compared with both analytical and numerical results.

Flat panel planar optic display. Revision 4/95

Energy Technology Data Exchange (ETDEWEB)

Veligdan, J.T.

1995-05-01

A prototype 10 inch flat panel Planar Optic display, (POD), screen has been constructed and tested. This display screen is comprised of hundreds of planar optic glass sheets bonded together with a cladding layer between each sheet where each glass sheet represents a vertical line of resolution. The display is 9 inches wide by 5 inches high and approximately 1 inch thick. A 3 milliwatt HeNe laser is used as the illumination source and a vector scanning technique is employed.

Morphing Planar Graph Drawings with a Polynomial Number of Steps

DEFF Research Database (Denmark)

Alamdari, Soroush; Angelini, Patrizio; Chan, Timothy M.

2013-01-01

In 1944, Cairns proved the following theorem: given any two straight-line planar drawings of a triangulation with the same outer face, there exists a morph (i.e., a continuous transformation) between the two drawings so that the drawing remains straight-line planar at all times. Cairns’s original...

Humidity build-up in electronic enclosures exposed to different geographical locations by RC modelling and reliability prediction

DEFF Research Database (Denmark)

Conseil-Gudla, H.; Staliulionis, Z.; Mohanty, S.

2018-01-01

according to this steady state (25 °C and 60% RH) have been calculated for the different climates, and the protection offered by the enclosures has been estimated under different casing materials and resistor-capacitor (RC) simulation. This method offers a way to predict the average value of failure rate...

Modeling of MHD natural convection in a square enclosure having an adiabatic square shaped body using Lattice Boltzmann Method

Directory of Open Access Journals (Sweden)

Ahmed Kadhim Hussein

2016-03-01

Full Text Available A steady laminar two-dimensional magneto-hydrodynamics (MHD natural convection flow in a square enclosure filled with an electrically conducting fluid is numerically investigated using Lattice Boltzmann Method (LBM. The left and right vertical sidewalls of the square enclosure are maintained at hot and cold temperatures respectively. The horizontal top and bottom walls are considered thermally insulated. An adiabatic square shaped body is located in the center of a square enclosure and an external magnetic field is applied parallel to the horizontal x-axis. In the present work, the following parametric ranges of the non-dimensional groups are utilized: Hartmann number is varied as 0 ⩽ Ha ⩽ 50, Rayleigh number is varied as 103 ⩽ Ra ⩽ 105, Prandtl number is varied 0.05 ⩽ Pr ⩽ 5. It is found that the Hartmann number, Rayleigh number, and Prandtl number have an important role on the flow and thermal characteristics. It is found that when the Hartmann number increases the average Nusselt number decreases. The results also explain that the effect of magnetic field on flow field increases by increasing Prandtl number. However, the Prandtl number effect on the average Nusselt number with a magnetic field is less than the case without a magnetic field. Comparisons with previously published numerical works are performed and good agreements between the results are observed.

Development of a Planar Undulator

International Nuclear Information System (INIS)

Deyhim, Alex; Johnson, Eric; Kulesza, Joe; Lyndaker, Aaron; Waterman, Dave; Eisert, Dave; Green, Michael A.; Rogers, Greg; Blomqvist, K. Ingvar

2007-01-01

The design of a planar pure permanent magnet undulator is presented. The design requirements and mechanical difficulties for holding, positioning, and driving the magnetic arrays are explored. The structural, thermal, and electrical considerations that influenced the design are then analyzed. And finally detailed magnetic measurements are presented

Poling of Planar Silica Waveguides

DEFF Research Database (Denmark)

Arentoft, Jesper; Kristensen, Martin; Jensen, Jesper Bo

1999-01-01

UV-written planar silica waveguides are poled using two different poling techniques, thermal poling and UV-poling. Thermal poling induces an electro-optic coefficient of 0.067 pm/V. We also demonstrate simultaneous UV-writing and UV-poling. The induced electro-optic effect shows a linear dependence...

Recent Studies on the Aromaticity and Antiaromaticity of Planar Cyclooctatetraene

Directory of Open Access Journals (Sweden)

Masahiko Iyoda

2010-02-01

Full Text Available Cyclooctatetraene (COT, the first 4nπ-electron system to be studied, adopts an inherently nonplanar tub-shaped geometry of D2d symmetry with alternating single and double bonds, and hence behaves as a nonaromatic polyene rather than an antiaromatic compound. Recently, however, considerable 8π-antiaromatic paratropicity has been shown to be generated in planar COT rings even with the bond alternated D4h structure. In this review, we highlight recent theoretical and experimental studies on the antiaromaticity of hypothetical and actual planar COT. In addition, theoretically predicted triplet aromaticity and stacked aromaticity of planar COT are also briefly described.

Spectroelectrochemical sensing: planar waveguides

Energy Technology Data Exchange (ETDEWEB)

Ross, Susan E.; Shi Yining; Seliskar, Carl J.; Heineman, William R

2003-09-30

The spectroelectrochemical sensor combines in a single device electrochemistry, spectroscopy, and selective partitioning into a film, giving improved selectivity for applications that involve complex samples. Sensing is based on the change in optical signal that accompanies electrochemical modulation of analyte that has partitioned into the film. Two classes of optical quality chemically-selective films based on two different host materials, namely, sol-gel processed silica and cross-linked poly(vinyl alcohol) have been developed. Films are typically 400-700 nm thick. Three types of sensor platforms are discussed: a multiple internal reflection (MIR) optic consisting of a bilayer of an indium tin oxide (ITO) optically transparent electrode deposited on a 1-mm thick glass substrate, a planar waveguide in which a potassium ion-exchanged BK7 glass waveguide (5-9 {mu}m thick) was over-coated with a thin film of ITO, and a planar waveguide in which a potassium ion-exchanged BK7 glass waveguide channel was formed and a pair of electrodes deposited along side the channel. These sensors were evaluated with ferrocyanide and a selective film of PDMDAAC-SiO{sub 2}, where PDMDAAC=poly(dimethyl diallylammonium chloride)

Spectroelectrochemical sensing: planar waveguides

International Nuclear Information System (INIS)

Ross, Susan E.; Shi Yining; Seliskar, Carl J.; Heineman, William R.

2003-01-01

The spectroelectrochemical sensor combines in a single device electrochemistry, spectroscopy, and selective partitioning into a film, giving improved selectivity for applications that involve complex samples. Sensing is based on the change in optical signal that accompanies electrochemical modulation of analyte that has partitioned into the film. Two classes of optical quality chemically-selective films based on two different host materials, namely, sol-gel processed silica and cross-linked poly(vinyl alcohol) have been developed. Films are typically 400-700 nm thick. Three types of sensor platforms are discussed: a multiple internal reflection (MIR) optic consisting of a bilayer of an indium tin oxide (ITO) optically transparent electrode deposited on a 1-mm thick glass substrate, a planar waveguide in which a potassium ion-exchanged BK7 glass waveguide (5-9 μm thick) was over-coated with a thin film of ITO, and a planar waveguide in which a potassium ion-exchanged BK7 glass waveguide channel was formed and a pair of electrodes deposited along side the channel. These sensors were evaluated with ferrocyanide and a selective film of PDMDAAC-SiO 2 , where PDMDAAC=poly(dimethyl diallylammonium chloride)

Transition of W7-X non-planar coils from manufacturing to assembly

Energy Technology Data Exchange (ETDEWEB)

Ehrke, G. [Max-Planck-Institut fuer Plasmaphysik (IPP), EURATOM Association, Wendelsteinstrasse 1, D-17491 Greifswald (Germany)], E-mail: gunnar.ehrke@ipp.mpg.de

2009-06-15

The main magnetic field of Wendelstein 7-X fusion experiment (W7-X) at Max-Planck-Institut fuer Plasmaphysik Greifswald, Germany will be provided by 50 non-planar coils and supported by 20 planar coils. The non-planar coils were delivered by a consortium (CON) consisting of Babcock Noell GmbH Germany (BNG) and ASG Superconductors S.p.A. Italy (ASG). The coil production ended with the delivery of the last non-planar coil in March 2008 at the manufacturing branch of BNG in Zeitz, Germany. The construction of the coils was characterised by design changes, many rework actions and resulting time delays. Due to these numerous adjustments and changes a continuous improvement process was needed. This paper will give an overview about the transition of the non-planar coils from the acceptance tests at the manufacturer site to the beginning of the assembly at IPP. Furthermore this report will highlight technical interfaces in the period of transition.

Paving the Way Towards Reactive Planar Spanner Construction in Wireless Networks

Science.gov (United States)

Frey, Hannes; Rührup, Stefan

A spanner is a subgraph of a given graph that supports the original graph's shortest path lengths up to a constant factor. Planar spanners and their distributed construction are of particular interest for geographic routing, which is an efficient localized routing scheme for wireless ad hoc and sensor networks. Planarity of the network graph is a key criterion for guaranteed delivery, while the spanner property supports efficiency in terms of path length. We consider the problem of reactive local spanner construction, where a node's local topology is determined on demand. Known message-efficient reactive planarization algorithms do not preserve the spanner property, while reactive spanner constructions with a low message overhead have not been described so far. We introduce the concept of direct planarization which may be an enabler of efficient reactive spanner construction. Given an edge, nodes check for all incident intersecting edges a certain geometric criterion and withdraw the edge if this criterion is not satisfied. We use this concept to derive a generic reactive topology control mechanism and consider two geometric criteria. Simulation results show that direct planarization increases the performance of localized geographic routing by providing shorter paths than existing reactive approaches.

Modeling Enclosure Design in Above-Grade Walls

Energy Technology Data Exchange (ETDEWEB)

Lstiburek, J. [Building Science Corporation, Westford, MA (United States); Ueno, K. [Building Science Corporation, Westford, MA (United States); Musunuru, S. [Building Science Corporation, Westford, MA (United States)

2016-03-01

This report describes the modeling of typical wall assemblies that have performed well historically in various climate zones. The WUFI (Warme und Feuchte instationar) software (Version 5.3) model was used. A library of input data and results are provided. The provided information can be generalized for application to a broad population of houses, within the limits of existing experience. The WUFI software model was calibrated or tuned using wall assemblies with historically successful performance. The primary performance criteria or failure criteria establishing historic performance was moisture content of the exterior sheathing. The primary tuning parameters (simulation inputs) were airflow and specifying appropriate material properties. Rational hygric loads were established based on experience - specifically rain wetting and interior moisture (RH levels). The tuning parameters were limited or bounded by published data or experience. The WUFI templates provided with this report supply useful information resources to new or less-experienced users. The files present various custom settings that will help avoid results that will require overly conservative enclosure assemblies. Overall, better material data, consistent initial assumptions, and consistent inputs among practitioners will improve the quality of WUFI modeling, and improve the level of sophistication in the field.

Planar and non-planar nucleus-acoustic shock structures in self-gravitating degenerate quantum plasma systems

Science.gov (United States)

Zaman, D. M. S.; Amina, M.; Dip, P. R.; Mamun, A. A.

2017-11-01

The basic properties of planar and non-planar (spherical and cylindrical) nucleus-acoustic (NA) shock structures (SSs) in a strongly coupled self-gravitating degenerate quantum plasma system (containing strongly coupled non-relativistically degenerate heavy nuclear species, weakly coupled non-relativistically degenerate light nuclear species, and inertialess non-/ultra-relativistically degenerate electrons) have been investigated. The generalized quantum hydrodynamic model and the reductive perturbation method have been used to derive the modified Burgers equation. It is shown that the strong correlation among heavy nuclear species acts as the source of dissipation and is responsible for the formation of the NA SSs with positive (negative) electrostatic (self-gravitational) potential. It is also observed that the effects of non-/ultra-relativistically degenerate electron pressure, dynamics of non-relativistically degenerate light nuclear species, spherical geometry, etc., significantly modify the basic features of the NA SSs. The applications of our results in astrophysical compact objects like white dwarfs and neutron stars are briefly discussed.

Planar screening by charge polydisperse counterions

Science.gov (United States)

Trulsson, M.; Trizac, E.; Šamaj, L.

2018-01-01

We study how a neutralising cloud of counterions screens the electric field of a uniformly charged planar membrane (plate), when the counterions are characterised by a distribution of charges (or valence), n(q) . We work out analytically the one-plate and two-plate cases, at the level of non-linear Poisson-Boltzmann theory. The (essentially asymptotic) predictions are successfully compared to numerical solutions of the full Poisson-Boltzmann theory, but also to Monte Carlo simulations. The counterions with smallest valence control the long-distance features of interactions, and may qualitatively change the results pertaining to the classic monodisperse case where all counterions have the same charge. Emphasis is put on continuous distributions n(q) , for which new power-laws can be evidenced, be it for the ionic density or the pressure, in the one- and two-plates situations respectively. We show that for discrete distributions, more relevant for experiments, these scaling laws persist in an intermediate but yet observable range. Furthermore, it appears that from a practical point of view, hallmarks of the continuous n(q) behaviour are already featured by discrete mixtures with a relatively small number of constituents.

Automated curved planar reformation of 3D spine images

International Nuclear Information System (INIS)

Vrtovec, Tomaz; Likar, Bostjan; Pernus, Franjo

2005-01-01

Traditional techniques for visualizing anatomical structures are based on planar cross-sections from volume images, such as images obtained by computed tomography (CT) or magnetic resonance imaging (MRI). However, planar cross-sections taken in the coordinate system of the 3D image often do not provide sufficient or qualitative enough diagnostic information, because planar cross-sections cannot follow curved anatomical structures (e.g. arteries, colon, spine, etc). Therefore, not all of the important details can be shown simultaneously in any planar cross-section. To overcome this problem, reformatted images in the coordinate system of the inspected structure must be created. This operation is usually referred to as curved planar reformation (CPR). In this paper we propose an automated method for CPR of 3D spine images, which is based on the image transformation from the standard image-based to a novel spine-based coordinate system. The axes of the proposed spine-based coordinate system are determined on the curve that represents the vertebral column, and the rotation of the vertebrae around the spine curve, both of which are described by polynomial models. The optimal polynomial parameters are obtained in an image analysis based optimization framework. The proposed method was qualitatively and quantitatively evaluated on five CT spine images. The method performed well on both normal and pathological cases and was consistent with manually obtained ground truth data. The proposed spine-based CPR benefits from reduced structural complexity in favour of improved feature perception of the spine. The reformatted images are diagnostically valuable and enable easier navigation, manipulation and orientation in 3D space. Moreover, reformatted images may prove useful for segmentation and other image analysis tasks

Microscale Syntheses, Reactions, and 1H NMR Spectroscopic Investigations of Square Planar Macrocyclic Tetraamido-N Cu(III) Complexes Relevant to Green Chemistry

Science.gov (United States)

Uffelman, Erich S.; Doherty, Jonathan R.; Schulze, Carl; Burke, Amy L.; Bonnema, Kristen R.; Watson, Tanya T.; Lee, Daniel W., III

2004-01-01

Microscale fusions, description, and spectroscopic analysis of the reactivity of a square planar Cu(III) complex significant to green chemistry, are presented. The experiment also includes nine focal points on which pre-lab and post-lab questions are based, and the final exams reflect the students' comprehension of these and other features of…

Conservation of Planar Polarity Pathway Function Across the Animal Kingdom.

Science.gov (United States)

Hale, Rosalind; Strutt, David

2015-01-01

Planar polarity is a well-studied phenomenon resulting in the directional coordination of cells in the plane of a tissue. In invertebrates and vertebrates, planar polarity is established and maintained by the largely independent core and Fat/Dachsous/Four-jointed (Ft-Ds-Fj) pathways. Loss of function of these pathways can result in a wide range of developmental or cellular defects, including failure of gastrulation and problems with placement and function of cilia. This review discusses the conservation of these pathways across the animal kingdom. The lack of vital core pathway components in basal metazoans suggests that the core planar polarity pathway evolved shortly after, but not necessarily alongside, the emergence of multicellularity.

Optimization of planar self-collimating photonic crystals.

Science.gov (United States)

Rumpf, Raymond C; Pazos, Javier J

2013-07-01

Self-collimation in photonic crystals has received a lot of attention in the literature, partly due to recent interest in silicon photonics, yet no performance metrics have been proposed. This paper proposes a figure of merit (FOM) for self-collimation and outlines a methodical approach for calculating it. Performance metrics include bandwidth, angular acceptance, strength, and an overall FOM. Two key contributions of this work include the performance metrics and identifying that the optimum frequency for self-collimation is not at the inflection point. The FOM is used to optimize a planar photonic crystal composed of a square array of cylinders. Conclusions are drawn about how the refractive indices and fill fraction of the lattice impact each of the performance metrics. The optimization is demonstrated by simulating two spatially variant self-collimating photonic crystals, where one has a high FOM and the other has a low FOM. This work gives optical designers tremendous insight into how to design and optimize robust self-collimating photonic crystals, which promises many applications in silicon photonics and integrated optics.

An overview of modeling methods for thermal mixing and stratification in large enclosures for reactor safety analysis

Energy Technology Data Exchange (ETDEWEB)

Haihua Zhao; Per F. Peterson

2010-10-01

Thermal mixing and stratification phenomena play major roles in the safety of reactor systems with large enclosures, such as containment safety in current fleet of LWRs, long-term passive containment cooling in Gen III+ plants including AP-1000 and ESBWR, the cold and hot pool mixing in pool type sodium cooled fast reactor systems (SFR), and reactor cavity cooling system behavior in high temperature gas cooled reactors (HTGR), etc. Depending on the fidelity requirement and computational resources, 0-D steady state models (heat transfer correlations), 0-D lumped parameter based transient models, 1-D physical-based coarse grain models, and 3-D CFD models are available. Current major system analysis codes either have no models or only 0-D models for thermal stratification and mixing, which can only give highly approximate results for simple cases. While 3-D CFD methods can be used to analyze simple configurations, these methods require very fine grid resolution to resolve thin substructures such as jets and wall boundaries. Due to prohibitive computational expenses for long transients in very large volumes, 3-D CFD simulations remain impractical for system analyses. For mixing in stably stratified large enclosures, UC Berkeley developed 1-D models basing on Zuber’s hierarchical two-tiered scaling analysis (HTTSA) method where the ambient fluid volume is represented by 1-D transient partial differential equations and substructures such as free or wall jets are modeled with 1-D integral models. This allows very large reductions in computational effort compared to 3-D CFD modeling. This paper will present an overview on important thermal mixing and stratification phenomena in large enclosures for different reactors, major modeling methods and their advantages and limits, potential paths to improve simulation capability and reduce analysis uncertainty in this area for advanced reactor system analysis tools.

Optically amplifying planar glass waveguides: Laser on a chip

DEFF Research Database (Denmark)

Guldberg-Kjær, Søren Andreas

with UV-light and that permanent Bragg-gratings can be induced. Planar waveguide lasers with integrated Bragg-gratings are manufactured and characterised. It is shown that linewidths below 125 kHz and output powers around 0.5 mW can be obtained, and that the manufactured lasers are resistant to mechanical...... lightwave circuits, as well as provide the gain medium for integrated planar waveguide lasers. The work and the obtained results are presented in this thesis: The manufacturing of silica thin films is described and it is shown that the refractive index of the films can be controlled by germanium co...... as well as thermal influence. A simple method for producing an array of planar waveguide lasers is presented and it is shown that the difference in output wavelength of the individual lasers can be controlled with great accuracy....

Planar waveguide amplifiers and laser in erbium doped silica

DEFF Research Database (Denmark)

Guldberg-Kjær, Søren Andreas; Kristensen, Martin

1999-01-01

with UV-light and that permanent Bragg-gratings can be induced. Planar waveguide lasers with integrated Bragg-gratings are manufactured and characterised. It is shown that linewidths below 125 kHz and output powers around 0.5 mW can be obtained, and that the manufactured lasers are resistant to mechanical...... lightwave circuits, as well as provide the gain medium for integrated planar waveguide lasers. The work and the obtained results are presented in this thesis: The manufacturing of silica thin films is described and it is shown that the refractive index o fthe films can be controlled by germanium co...... as well as thermal influence. A simple method for producing an array of planar waveguide lasers is presented and it is shown that the difference in output wavelength of the individual lasers can be controlled with great accuracy....

Growth and characterization of textured well-faceted ZnO on planar Si(100, planar Si(111, and textured Si(100 substrates for solar cell applications

Directory of Open Access Journals (Sweden)

Chin-Yi Tsai

2017-09-01

Full Text Available In this work, textured, well-faceted ZnO materials grown on planar Si(100, planar Si(111, and textured Si(100 substrates by low-pressure chemical vapor deposition (LPCVD were analyzed by X-ray diffraction (XRD, scanning electron microscopy (SEM, atomic force microscopy (AFM, and cathode luminescence (CL measurements. The results show that ZnO grown on planar Si(100, planar Si(111, and textured Si(100 substrates favor the growth of ZnO(110 ridge-like, ZnO(002 pyramid-like, and ZnO(101 pyramidal-tip structures, respectively. This could be attributed to the constraints of the lattice mismatch between the ZnO and Si unit cells. The average grain size of ZnO on the planar Si(100 substrate is slightly larger than that on the planar Si(111 substrate, while both of them are much larger than that on the textured Si(100 substrate. The average grain sizes (about 10–50 nm of the ZnO grown on the different silicon substrates decreases with the increase of their strains. These results are shown to strongly correlate with the results from the SEM, AFM, and CL as well. The reflectance spectra of these three samples show that the antireflection function provided by theses samples mostly results from the nanometer-scaled texture of the ZnO films, while the micrometer-scaled texture of the Si substrate has a limited contribution. The results of this work provide important information for optimized growth of textured and well-faceted ZnO grown on wafer-based silicon solar cells and can be utilized for efficiency enhancement and optimization of device materials and structures, such as heterojunction with intrinsic thin layer (HIT solar cells.

$1$-string $B_2$-VPG representation of planar graphs

Directory of Open Access Journals (Sweden)

Therese Biedl

2016-09-01

Full Text Available In this paper, we prove that every planar graph has a 1-string $B_2$-VPG representation—a string representation using paths in a rectangular grid that contain at most two bends. Furthermore, two paths representing vertices $u,v$ intersect precisely once whenever there is an edge between $u$ and $v$. We also show that only a subset of the possible curve shapes is necessary to represent $4$-connected planar graphs.

Study of silicon-silicon nitride interface properties on planar (1 0 0), planar (1 1 1) and textured surfaces using deep-level transient spectroscopy

International Nuclear Information System (INIS)

Gong, Chun; Simoen, Eddy; Posthuma, Niels E; Van Kerschaver, Emmanuel; Poortmans, Jef; Mertens, Robert

2010-01-01

Deep-level transient spectroscopy (DLTS) has been applied to metal-insulator-semiconductor (MIS) capacitors fabricated on planar (1 0 0), planar (1 1 1) orientations and textured n-type silicon wafers. Low frequency direct plasma-enhanced chemical vapour deposition Si-SiN x interface properties with and without plasma NH 3 pre-treatment, with and without rapid thermal annealing (RTA) have been investigated. It is shown that three different kinds of defect states are identified at the Si-SiN x interface. For the planar (1 0 0) surface, samples with plasma NH 3 pre-treatment plus RTA show the lowest DLTS signals, which suggests the lowest overall interface states density. For planar (1 1 1) Si surfaces, plasma NH 3 pre-treatment and RTA yield a small improvement. With the textured surface, the RTA step improves the surface passivation quality further but no obvious impact is found with plasma NH 3 pre-treatment. Energy-dependent electron capture cross sections were also measured by small-pulse DLTS. The capture cross sections depend strongly on the energy level and decrease towards the conduction band edge.

Comparison Of Planar And Wound Transformers For Flyback Forward And Half-Bridge Space Power Converters

Science.gov (United States)

Bjorklund, Thomas; Andreasen, John; Brosen, Finn; Matthiesen, Erik; Poulsen, Ole

2011-10-01

Planar technology has now entered the space domain. The big advantages of planar technology are; - Low profile - Excellent repeatability - Economical assembly - Mechanical integrity - Superior thermal characteristics This is why the general power industries increasingly are using planar magnetics in more and more applications, and therefore also why we see a rising demand for the usability of the planar technology among space application developers. The differences between wound and planar transformers have been mapped with a detailed look on the various parasitic component values, such as DC- and AC- resistance, Leakage Inductance and stray capacitance, and revealed the magnitude of the advantages of planar technology. This technical solution is proven in prototypes that have been built in different combination of PCB's and copper foil, with more or less interleaving of windings. Furthermore the transformers have been designed with several outputs stacked together with a fairly high number of primary turns, in order to have planar transformers similar to the wound types that are generally used for space applications.

L(2, 1-Labelings of Some Families of Oriented Planar Graphs

Directory of Open Access Journals (Sweden)

Sen Sagnik

2014-02-01

Full Text Available In this paper we determine, or give lower and upper bounds on, the 2-dipath and oriented L(2, 1-span of the family of planar graphs, planar graphs with girth 5, 11, 16, partial k-trees, outerplanar graphs and cacti.

Comparison of apparent diffusion coefficients (ADCs) between two-point and multi-point analyses using high-B-value diffusion MR imaging

International Nuclear Information System (INIS)

Kubo, Hitoshi; Maeda, Masayuki; Araki, Akinobu

2001-01-01

We evaluated the accuracy of calculating apparent diffusion coefficients (ADCs) using high-B-value diffusion images. Echo planar diffusion-weighted MR images were obtained at 1.5 tesla in five standard locations in six subjects using gradient strengths corresponding to B values from 0 to 3000 s/mm 2 . Estimation of ADCs was made using two methods: a nonlinear regression model using measurements from a full set of B values (multi-point method) and linear estimation using B values of 0 and max only (two-point method). A high correlation between the two methods was noted (r=0.99), and the mean percentage differences were -0.53% and 0.53% in phantom and human brain, respectively. These results suggest there is little error in estimating ADCs calculated by the two-point technique using high-B-value diffusion MR images. (author)

Development of planar SOE/SOFC reversible cell

International Nuclear Information System (INIS)

Kusunoki, A.; Matsubara, H.; Kikuoka, Y.; Yanagi, C.; Kugimiya, K.; Yoshino, M.; Tokura, M.; Watanabe, K.; Ueda, S.; Sumi, M.; Miyamoto, H.; Tokunaga, S.

1993-01-01

A new energy storage system using SOE/SOFC (solid oxide electrolysis-solid oxide fuel cells) reversible cells is presented, where a unit cell works as a fuel cell during a period of high electric power demand and alternately works as an electrolysis cell during a period of low power demand. A planar cell configuration is used which allows for a compact and low cost energy storage and load leveling system for power stations. Tests were performed to verify the reversibility of the planar cell, at 1000 deg C, with YSZ (Yttria stabilized zirconia) as the solid electrolyte, to improve the cell performance by reducing the overvoltage in electrolysis, and to obtain fundamental characteristics of a reversible cell. 3 figs

An iterative method for the canard explosion in general planar systems

DEFF Research Database (Denmark)

Brøns, Morten

2013-01-01

The canard explosion is the change of amplitude and period of a limit cycle born in a Hopf bifurcation in a very narrow parameter interval. The phenomenon is well understood in singular perturbation problems where a small parameter controls the slow/fast dynamics. However, canard explosions are a...... on the van der Pol equation, showing that the asymptotics of the method is correct, and on a templator model for a self-replicating system....... are also observed in systems where no such parameter can obviously be identied. Here we show how the iterative method of Roussel and Fraser, devised to construct regular slow manifolds, can be used to determine a canard point in a general planar system of nonlinear ODEs. We demonstrate the method...

On the tautomerism, planarity, and vibrations of phospholes

International Nuclear Information System (INIS)

Oziminski, Wojciech P.; Dobrowolski, Jan Cz.

2005-01-01

The PH and CH tautomers of mono-, di-, tri-, tetra-, and pentaphospholes were calculated at the B3LYP/aug-cc-pVTZ level. Except for 1,2,3-triphosphole and pentaphosphole, the most stable phosphole form is one of the CH tautomers. For 1,2-diphosphole, 1,3-diphosphole, and 1,2,4-triphosphole, the energy difference between the tautomers is large and only one tautomer may be observed. For other phospholes, especially tetraphosphole, two tautomers may coexist. Non-planarity of the five membered ring is present only in the σ 3 λ 3 -P atom containing molecules, i.e., PH type of tautomers, while in the CH type of tautomers the ring is planar. As earlier reported by Nyulaszi, the PH tautomers flatten, and the energy difference between PH phosphole and the planar transition state structure decreases, as the number of P atoms in the phosphole molecule is increased. Bond length changes were discussed in terms of configuration of the atoms attached to the bond, and the molecular frequency variations were examined according to the different surroundings of the appropriate vibrators

Process for the dismantling of buried equipment, with a contamination risk and eventually irradiating, and intervention enclosure for this process

International Nuclear Information System (INIS)

Bodin, F.; Saublet, J.C.

1991-01-01

Dismantling of buried equipment, for instance abandoned effluent pipes,is made by unitary sections under mobile enclosure with a self-supporting structure and a floor provided with a long central aperture giving access to the section to dismantle

Frescoed Vaults: Accuracy Controlled Simplified Methodology for Planar Development of Three-Dimensional Textured Models

Directory of Open Access Journals (Sweden)

Marco Giorgio Bevilacqua

2016-03-01

Full Text Available In the field of documentation and preservation of cultural heritage, there is keen interest in 3D metric viewing and rendering of architecture for both formal appearance and color. On the other hand, operative steps of restoration interventions still require full-scale, 2D metric surface representations. The transition from 3D to 2D representation, with the related geometric transformations, has not yet been fully formalized for planar development of frescoed vaults. Methodologies proposed so far on this subject provide transitioning from point cloud models to ideal mathematical surfaces and projecting textures using software tools. The methodology used for geometry and texture development in the present work does not require any dedicated software. The different processing steps can be individually checked for any error introduced, which can be then quantified. A direct accuracy check of the planar development of the frescoed surface has been carried out by qualified restorers, yielding a result of 3 mm. The proposed methodology, although requiring further studies to improve automation of the different processing steps, allowed extracting 2D drafts fully usable by operators restoring the vault frescoes.

One-point functions in defect CFT and integrability

Energy Technology Data Exchange (ETDEWEB)

Leeuw, Marius de; Kristjansen, Charlotte [The Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, Copenhagen Ø, DK-2100 (Denmark); Zarembo, Konstantin [NORDITA, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, Stockholm, SE-106 91 (Sweden); Department of Physics and Astronomy, Uppsala University, Uppsala, SE-751 08 (Sweden)

2015-08-19

We calculate planar tree level one-point functions of non-protected operators in the defect conformal field theory dual to the D3-D5 brane system with k units of the world volume flux. Working in the operator basis of Bethe eigenstates of the Heisenberg XXX{sub 1/2} spin chain we express the one-point functions as overlaps of these eigenstates with a matrix product state. For k=2 we obtain a closed expression of determinant form for any number of excitations, and in the case of half-filling we find a relation with the Néel state. In addition, we present a number of results for the limiting case k→∞.

Three sets of crystallographic sub-planar structures in quartz formed by tectonic deformation

Science.gov (United States)

Derez, Tine; Pennock, Gill; Drury, Martyn; Sintubin, Manuel

2016-05-01

In quartz, multiple sets of fine planar deformation microstructures that have specific crystallographic orientations parallel to planes with low Miller-Bravais indices are commonly considered as shock-induced planar deformation features (PDFs) diagnostic of shock metamorphism. Using polarized light microscopy, we demonstrate that up to three sets of tectonically induced sub-planar fine extinction bands (FEBs), sub-parallel to the basal, γ, ω, and π crystallographic planes, are common in vein quartz in low-grade tectonometamorphic settings. We conclude that the observation of multiple (2-3) sets of fine scale, closely spaced, crystallographically controlled, sub-planar microstructures is not sufficient to unambiguously distinguish PDFs from tectonic FEBs.

Numerical Analysis Of Buckling Of Von Mises Planar Truss

Directory of Open Access Journals (Sweden)

Kalina Martin

2015-12-01

Full Text Available A computational algorithm of a discrete model of von Mises planar steel truss is presented. The structure deformation is evaluated by seeking the minimal potential energy. The critical force invented by mathematical solution was compared with solution by computer algorithm. Symmetric and asymmetric effects of initial shape of geometric imperfection of axis of struts are used in model. The shapes of buckling of von Mises planar truss of selected vertical displacement of top joint are shown.

Multi-projector auto-calibration and placement optimization for non-planar surfaces

Science.gov (United States)

Li, Dong; Xie, Jinghui; Zhao, Lu; Zhou, Lijing; Weng, Dongdong

2015-10-01

Non-planar projection has been widely applied in virtual reality and digital entertainment and exhibitions because of its flexible layout and immersive display effects. Compared with planar projection, a non-planar projection is more difficult to achieve because projector calibration and image distortion correction are difficult processes. This paper uses a cylindrical screen as an example to present a new method for automatically calibrating a multi-projector system in a non-planar environment without using 3D reconstruction. This method corrects the geometric calibration error caused by the screen's manufactured imperfections, such as an undulating surface or a slant in the vertical plane. In addition, based on actual projection demand, this paper presents the overall performance evaluation criteria for the multi-projector system. According to these criteria, we determined the optimal placement for the projectors. This method also extends to surfaces that can be parameterized, such as spheres, ellipsoids, and paraboloids, and demonstrates a broad applicability.

Feasibility of Parylene Coating for Planar Electroporation Copper Electrodes

Directory of Open Access Journals (Sweden)

Vitalij NOVICKIJ

2017-08-01

Full Text Available This paper is focused on the feasibility study of parylene as a biocompatible coating for planar electroporation microelectrodes. The planar parallel and the circular interdigitated electrodes are applied in the analysis. The electrodes feature 100 μm width with a 300 μm gap between anode and cathode. The parylene coating thickness was varied in the 250 nm – 2 μm range. The resultant electric field distribution evaluation has been performed using the finite element method. The electrodes have been applied in electroporation experiments with Saprolegnia parasitica. For reference the additional experiments using conventional electroporation cuvette (1 mm gap have been performed. It has been determined that the parylene coating with hydrophobic properties has limited applicability for the passivation of the planar electroporation electrodes.DOI: http://dx.doi.org/10.5755/j01.ms.23.2.14953

Long-term fate and bioavailability of sediment associated 2,3,7,8-tetrachlorodibenzofuran in littoral enclosures

Energy Technology Data Exchange (ETDEWEB)

Currie, R.S.; Fairchild, W.L.; Holoka, M.H.; Muir, D.C.G.

2000-06-01

the fate and bioavailability of 2,3,7,8-tetrachlorodibenzofuran (TCDF; 4,6-tritium labeled) was examined over a 3-year period in littoral enclosures in a small oligotrophic lake in the Experimental Lakes Area. Tetrachlorodibenzofuran was added as a single dose or as five small multiple additions over a 5-d period in a sediment slurry. Tetrachlorodibenzofuran was rapidly redistributed, mainly to bottom sediments reflecting removal on settling particles. Between 0 and 120 d. 80 to 90% of TCDF in the water column was associated with particles (>1 {micro}m). The highest concentration of TCDF in suspended particles was consistently observed in the smallest size fraction (0.22--1 {micro}m) at 326 to 464 d post treatment. Mode of addition had no effect on TCDF concentrations in water or surficial sediments or pore waters throughout the experiment. Mean TCDF concentrations in surficial sediment were 1.830 {+-} 1.180 pg/g whereas they averaged 1.260 {+-} 596 pg/g OC from 318 to 851 d post treatment. Increasing concentrations of TCDE in lower sediment layers at 952 d suggests that TCDF was either diffusing into the sediment or undergoing burial. Fugacity (f) calculations indicated that the TCDF in enclosures shifted from disequilibrium favoring the water column to a disequilibrium with respect to bottom sediments from day 21 onward. Initially, TCDF was more bioavailable to filtering and deposit feeders (mussels, Chironomidae, Hexagenia sp., and zooplankton) in enclosures receiving multiple additions; however, differences were rarely statistically significant. Concentrations of TCDF in all organisms were initially high, and they decreased in later sampling periods. Biota--sediment-accumulation factors (BSAFs) in mussels and crayfish were >1 in the early sampling periods, which reflected greater bioavailability of the added particle-borne TCDF. By 851 d, BSAFs had declined to 0.02 to 0.04, reflecting removal of TCDF from the water column and from surficial sediments.

Planar-Processed Polymer Transistors.

Science.gov (United States)

Xu, Yong; Sun, Huabin; Shin, Eul-Yong; Lin, Yen-Fu; Li, Wenwu; Noh, Yong-Young

2016-10-01

Planar-processed polymer transistors are proposed where the effective charge injection and the split unipolar charge transport are all on the top surface of the polymer film, showing ideal device characteristics with unparalleled performance. This technique provides a great solution to the problem of fabrication limitations, the ambiguous operating principle, and the performance improvements in practical applications of conjugated-polymer transistors. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tests of planar permanent magnet multipole focusing elements

International Nuclear Information System (INIS)

Cobb, J.; Tatchyn, R.

1993-08-01

In recent work, planar configurations of permanent magnets were proposed as substitutes for conventional current-driven iron quadrupoles in applications limited by small aperture sizes and featuring small beam occupation diameters. Important examples include the configuring of focusing lattices in small-gap insertion devices, and the implementation of compact mini-beta sections on linear or circular machines. In subsequent analysis, this approach was extended to sextupoles and higher-order multipoles. In this paper we report on initial measurements conducted at the Stanford Linear Accelerator Center on recently fabricated planar permanent magnet quadrupoles and sextupoles configured out of SmCo and NdFe/B

The planar cubic Cayley graphs

CERN Document Server

Georgakopoulos, Agelos

2018-01-01

The author obtains a complete description of the planar cubic Cayley graphs, providing an explicit presentation and embedding for each of them. This turns out to be a rich class, comprising several infinite families. He obtains counterexamples to conjectures of Mohar, Bonnington and Watkins. The author's analysis makes the involved graphs accessible to computation, corroborating a conjecture of Droms.

Casimir stress inside planar materials

Science.gov (United States)

Griniasty, Itay; Leonhardt, Ulf

2017-09-01

The Casimir force between macroscopic bodies is well understood, but not the Casimir force inside bodies. Guided by a physically intuitive picture, we develop the macroscopic theory of the renormalized Casimir stress inside planar materials (where the electromagnetic properties vary in one direction). Our theory may be applied in predicting how inhomogeneous fluids respond to Casimir forces.

Approximation by planar elastic curves

DEFF Research Database (Denmark)

Brander, David; Gravesen, Jens; Nørbjerg, Toke Bjerge

2016-01-01

We give an algorithm for approximating a given plane curve segment by a planar elastic curve. The method depends on an analytic representation of the space of elastic curve segments, together with a geometric method for obtaining a good initial guess for the approximating curve. A gradient......-driven optimization is then used to find the approximating elastic curve....

Fundamental losses in planar Bragg waveguides

NARCIS (Netherlands)

Vinogradov, A. V.; Mitrofanov, A. N.; Popov, A. V.; Fedin, M. A.

2007-01-01

This paper considers a planar Bragg waveguide. The guided modes and their dissipation due to the fundamental absorption are described. In the interacting-wave approximation, an analytical relation between the characteristics of the modes and parameters of the Bragg-waveguide geometry was

One-point functions of non-SUSY operators at arbitrary genus in a matrix model for type IIA superstrings

Directory of Open Access Journals (Sweden)

Tsunehide Kuroki

2017-06-01

Full Text Available In the previous paper, the authors pointed out correspondence between a supersymmetric double-well matrix model and two-dimensional type IIA superstring theory on a Ramond–Ramond background from the viewpoint of symmetry and spectrum. This was confirmed by agreement between planar correlation functions in the matrix model and tree-level amplitudes in the superstring theory. In order to investigate the correspondence further, in this paper we compute correlation functions to all order of genus expansion in the double scaling limit of the matrix model. One-point functions of operators protected by supersymmetry terminate at some finite order, whereas those of unprotected operators yield non-Borel summable series. The behavior of the latter is characteristic in string perturbation series, providing further evidence that the matrix model describes a string theory. Moreover, instanton corrections to the planar one-point functions are also computed, and universal logarithmic scaling behavior is found for non-supersymmetric operators.

One-point functions of non-SUSY operators at arbitrary genus in a matrix model for type IIA superstrings

Energy Technology Data Exchange (ETDEWEB)

Kuroki, Tsunehide, E-mail: kuroki@dg.kagawa-nct.ac.jp [General Eduction, National Institute of Technology, Kagawa College, 551 Kohda, Takuma-cho, Mitoyo, Kagawa 769-1192 (Japan); Sugino, Fumihiko, E-mail: fusugino@gmail.com [Okayama Institute for Quantum Physics, Furugyocho 1-7-36, Naka-ku, Okayama 703-8278 (Japan)

2017-06-15

In the previous paper, the authors pointed out correspondence between a supersymmetric double-well matrix model and two-dimensional type IIA superstring theory on a Ramond–Ramond background from the viewpoint of symmetry and spectrum. This was confirmed by agreement between planar correlation functions in the matrix model and tree-level amplitudes in the superstring theory. In order to investigate the correspondence further, in this paper we compute correlation functions to all order of genus expansion in the double scaling limit of the matrix model. One-point functions of operators protected by supersymmetry terminate at some finite order, whereas those of unprotected operators yield non-Borel summable series. The behavior of the latter is characteristic in string perturbation series, providing further evidence that the matrix model describes a string theory. Moreover, instanton corrections to the planar one-point functions are also computed, and universal logarithmic scaling behavior is found for non-supersymmetric operators.

One-point functions of non-SUSY operators at arbitrary genus in a matrix model for type IIA superstrings

International Nuclear Information System (INIS)

Kuroki, Tsunehide; Sugino, Fumihiko

2017-01-01

In the previous paper, the authors pointed out correspondence between a supersymmetric double-well matrix model and two-dimensional type IIA superstring theory on a Ramond–Ramond background from the viewpoint of symmetry and spectrum. This was confirmed by agreement between planar correlation functions in the matrix model and tree-level amplitudes in the superstring theory. In order to investigate the correspondence further, in this paper we compute correlation functions to all order of genus expansion in the double scaling limit of the matrix model. One-point functions of operators protected by supersymmetry terminate at some finite order, whereas those of unprotected operators yield non-Borel summable series. The behavior of the latter is characteristic in string perturbation series, providing further evidence that the matrix model describes a string theory. Moreover, instanton corrections to the planar one-point functions are also computed, and universal logarithmic scaling behavior is found for non-supersymmetric operators.

Planar Dirac diffusion

International Nuclear Information System (INIS)

Leo, Stefano de; Rotelli, Pietro

2009-01-01

We present the results of the planar diffusion of a Dirac particle by step and barrier potentials, when the incoming wave impinges at an arbitrary angle with the potential. Except for right-angle incidence this process is characterized by the appearance of spin flip terms. For the step potential, spin flip occurs for both transmitted and reflected waves. However, we find no spin flip in the transmitted barrier result. This is surprising because the barrier result may be derived directly from a two-step calculation. We demonstrate that the spin flip cancellation indeed occurs for each ''particle'' (wave packet) contribution. (orig.)

Preliminary Safety Analysis Report for the Transuranic Storage Area Retrieval Enclosure at the Idaho National Engineering Laboratory

International Nuclear Information System (INIS)

1993-03-01

This Transuranic Storage Area Retrieval Enclosure Preliminary Safety Analysis Report was completed as required by DOE Order 5480.23. The purpose of this document is to construct a safety basis that supports the design and permits construction of the facility. The facility has been designed to the requirements of a Radioactive Solid Waste Facility presented in DOE Order 6430.1A

A constant gradient planar accelerating structure for linac use

International Nuclear Information System (INIS)

Kang, Y.W.; Matthews, P.J.; Kustom, R.L.

1995-01-01

Planar accelerating millimeter-wave structures have been studied during the last few years at Argonne National Laboratory in collaboration with Technical University of Berlin. The cavity structures are intended to be manufactured by using x-ray lithography microfabrication technology. A complete structure consists of two identical planar half structures put together face-to-face. Since microfabrication technology can make a since-depth indentation on a planar substrate, realizing the constant impedance structure was possible but a constant gradient structure was difficult; changing the group velocity along the structure while maintaining the gap and the depth of the indentation constant was difficult. A constant gradient structure has been devised by introducing a cut between the adjacent cavity cells along the beam axis of each half structure. The width of the cut is varied along the longitudinal axis of the structure to have proper coupling between the cells. The result of the computer simulation on such structures is shown

Variation in visitor perceptions of a polar bear enclosure based on the presence of natural vs. un-natural enrichment items.

Science.gov (United States)

Kutska, Debra

2009-07-01

A debate exists among modern zoo staff as to whether or not the addition of un-naturalistic enrichment takes away from, or even defeats, the educational messages designers are trying to incorporate in naturalistic exhibits. A visitor study was conducted at the Central Park Zoo's polar bear exhibit in order to determine whether or not the type of enrichment in an enclosure actually alters guest perceptions. Visitors were exposed to one of two enrichment treatments in the bear enclosure: Naturalistic or Un-naturalistic. The results of this study suggest that enrichment type did not alter the perceptions of visitors. However, it did identify some of the different ways adults and youths perceive animals and zoos. Additionally, the study highlighted the varying perceptions individuals have of the concept of polar bears vs. their perceptions of the captive individuals at the Central Park Zoo. Implications for enrichment usage and exhibit design are discussed.

Virtual sensors for active noise control in acoustic-structural coupled enclosures using structural sensing: robust virtual sensor design.

Science.gov (United States)

Halim, Dunant; Cheng, Li; Su, Zhongqing

2011-03-01

The work was aimed to develop a robust virtual sensing design methodology for sensing and active control applications of vibro-acoustic systems. The proposed virtual sensor was designed to estimate a broadband acoustic interior sound pressure using structural sensors, with robustness against certain dynamic uncertainties occurring in an acoustic-structural coupled enclosure. A convex combination of Kalman sub-filters was used during the design, accommodating different sets of perturbed dynamic model of the vibro-acoustic enclosure. A minimax optimization problem was set up to determine an optimal convex combination of Kalman sub-filters, ensuring an optimal worst-case virtual sensing performance. The virtual sensing and active noise control performance was numerically investigated on a rectangular panel-cavity system. It was demonstrated that the proposed virtual sensor could accurately estimate the interior sound pressure, particularly the one dominated by cavity-controlled modes, by using a structural sensor. With such a virtual sensing technique, effective active noise control performance was also obtained even for the worst-case dynamics. © 2011 Acoustical Society of America

Effect of Darcy, fluid Rayleigh and heat generation parameters on natural convection in a porous square enclosure: A Brinkman-extended Darcy model

International Nuclear Information System (INIS)

Das, S.; Sahoo, R.K.

1999-01-01

Analysis of flow and convective heat transfer in volumetrically heated porous layer has become a separate topic for research in the last twenty five years in view of its importance in various engineering applications, such as heat removal from nuclear fuel debris, heat transfer associated with storage of nuclear waste, exothermic reaction in packed-bed reactors, heat recovery from geothermal systems and particularly in the field of large storage systems of agricultural products. Here, a pressure-velocity solution for natural convection for fluid saturated heat generating porous medium in a square enclosure is analyzed by finite element method. The numerical solutions obtained for wide range of fluid Rayleigh number, Ra f , Darcy number, Da, and heat generating number, Q d . The justification for taking these non-dimensional parameters independently is to establish the effect of individual parameters on flow patterns. It has been observed that peak temperature occurs at the top central part and weaker velocity prevails near the vertical walls of the enclosure due to the heat generation parameter alone. On comparison, the modified Rayleigh number used by the earlier investigators, can not explain explicitly the effect of heat generation parameter on natural convection within an enclosure having differentially heated vertical walls. At higher Darcy number, the peak temperature and peak velocity are comparatively more, resulting in better enhancement of heat transfer rate

Planar Near-Field Measurements of Ground Penetrating Radar Antennas

DEFF Research Database (Denmark)

Meincke, Peter; Hansen, Thorkild

2004-01-01

Planar near-field measurements are formulated for a general ground penetrating radar (GPR) antenna. A total plane-wave scattering matrix is defined for the system consisting of the GPR antenna and the planar air-soil interface. The transmitting spectrum of the GPR antenna is expressed in terms...... of measurements obtained with a buried probe as the GPR antenna moves over a scan plane on the ground. A numerical example in which the scan plane is finite validates the expressions for the spectrum of the GPR antenna....

A Classification-oriented Method of Feature Image Generation for Vehicle-borne Laser Scanning Point Clouds

Directory of Open Access Journals (Sweden)

YANG Bisheng

2016-02-01

Full Text Available An efficient method of feature image generation of point clouds to automatically classify dense point clouds into different categories is proposed, such as terrain points, building points. The method first uses planar projection to sort points into different grids, then calculates the weights and feature values of grids according to the distribution of laser scanning points, and finally generates the feature image of point clouds. Thus, the proposed method adopts contour extraction and tracing means to extract the boundaries and point clouds of man-made objects (e.g. buildings and trees in 3D based on the image generated. Experiments show that the proposed method provides a promising solution for classifying and extracting man-made objects from vehicle-borne laser scanning point clouds.

Surfaces foliated by planar geodesics: a model forcurved wood design

DEFF Research Database (Denmark)

Brander, David; Gravesen, Jens

2017-01-01

Surfaces foliated by planar geodesics are a natural model for surfaces made from wood strips. We outline how to construct all solutions, and produce non-trivial examples, such as a wood-strip Klein bottle......Surfaces foliated by planar geodesics are a natural model for surfaces made from wood strips. We outline how to construct all solutions, and produce non-trivial examples, such as a wood-strip Klein bottle...

Modelling and experimental study of the behavior of radon and radon decay products in an enclosure. Application to houses

International Nuclear Information System (INIS)

Gouronnec, A.M.

1995-01-01

Since the eighties, more and more studies were performed about radon and its decay products in houses with one of the aim being the estimation of the dose received by their inhabitants. Then, the principal objective of this work is to describe the behaviour of radon and its decay products within a dwelling. In the first part to the report, a few definitions are given and data from literature give an idea of indoor radon and radon decay products activities and/or size distribution. Aspects of dosimetry are presented too. In the second part of the work, a mathematical model, called 'PRADDO' of Physic of Radon and radon Decay products in Domestic environment is developed on the basis of the classical model written by Jacobi in 1972. On the one hand, it has to predict radon decay products activities in systems consisting in one or more enclosure(s), from radon activity and from ambient aerosol concentration and size distribution. On the other hand, one part of the model is assigned to study the influence of the entry model parameters variation on the calculated quantities. Then, in the third part of the work, two experimental studies are realised in order to compare measurements to modelization. The first experimentation is a laboratory work, made on the test bench ICARE from IPSN, and the second one consists in describing the basement of an occupied house from Brittany. In the two cases, the comparison between experiments and modelling shows a good agreement if particles are present in the air, but any conclusion is made when is no aerosol in the enclosure. (author). 158 refs., 81 figs., 42 tabs

Geometrical aspects of a hollow-cathode planar magnetron

International Nuclear Information System (INIS)

Wang, Z.; Cohen, S.A.

1999-01-01

A hollow-cathode planar magnetron (HCPM), built by surrounding a planar sputtering-magnetron cathode with a hollow-cathode structure (HCS) [Z. Wang and S. A. Cohen, J. Vac. Sci. Technol. A 17, 77 (1999)], is operable at substantially lower pressures than its planar-magnetron counterpart. HCPM operational parameters depend on the inner diameter D and length L of its cylindrical HCS. Only when L is greater than L 0 , a critical length, is the HCPM operable in the new low-pressure regime. The critical length varies with HCS inner diameter D. Explanations of the lower operational pressure regime, critical length, and plasma shape are proposed and compared with a one-dimension diffusion model for energetic electron transport. At pressures above 1 mTorr, Bohm diffusion (temperature congruent primary electron energy), with an ambipolar constraint, can explain the ion - electron pair creation required to sustain the discharge. At the lowest pressure, ∼0.3 mTorr, collision-limited diffusion creates fewer ion - electron pairs than required for steady state and therefore cannot explain the experimental data. The critical length L 0 is consistent with the magnetization length of the primary electrons. copyright 1999 American Institute of Physics

Planar PCB Hazards to Fish, Wildlife, and Invertebrates: A Synoptic Review

Science.gov (United States)

Eisler, R.; Belisle, A.A.

1996-01-01

Ecological and toxicological aspects of polychlorinated biphenyls (PCBs) in the environment are reviewed with emphasis on biologically active congeners and fish and wildlife. Subtopics include sources and uses, chemical and biochemical properties, concentrations in field collections, lethal and sublethal effects, and recommendations for the protection of sensitive resources. All production of PCBs in the United States ceased in 1977. Of the 1.2 million tons of PCBs manufactured to date, about 65% are still in use in electrical equipment and 31% in various environmental compartments, and 4% were degraded or incinerated. The 209 PCB congeners and their metabolites show wide differences in biological effects. A significant part of the toxicity associated with commercial PCB mixtures is related to the presence of about 20 planar congeners, i.e., congeners without chlorine substitution in the ortho position. Toxic planar congeners, like other PCB congeners, have been detected in virtually all analyzed samples, regardless of collection locale. Planar PCB concentrations were usually highest in samples from near urban areas and in fat and liver tissues, filter-feeding bivalve mollusks, fish-eating birds, and carnivorous marine mammals. Adverse effects of planar PCBs on growth, survival, and reproduction are highly variable because of numerous biotic and abiotic modifiers, including interaction with other chemicals. In general, embryos and juveniles were the most sensitive stages tested to planar PCBs, and the chinook salmon, domestic chicken, mink, rhesus macaque, and laboratory white rat were among the most sensitive species. for protection of natural resources, most authorities now recommend (1) analyzation of environmental samples for planar and other potentially hazardous congeners; (2) exposure studies with representative species and specific congeners, alone and in combination with other environmental contaminants; (3) clarification of existing structure

Design and investigation of properties of nanocrystalline diamond optical planar waveguides.

Science.gov (United States)

Prajzler, Vaclav; Varga, Marian; Nekvindova, Pavla; Remes, Zdenek; Kromka, Alexander

2013-04-08

Diamond thin films have remarkable properties comparable with natural diamond. Because of these properties it is a very promising material for many various applications (sensors, heat sink, optical mirrors, chemical and radiation wear, cold cathodes, tissue engineering, etc.) In this paper we report about design, deposition and measurement of properties of optical planar waveguides fabricated from nanocrystalline diamond thin films. The nanocrystalline diamond planar waveguide was deposited by microwave plasma enhanced chemical vapor deposition and the structure of the deposited film was studied by scanning electron microscopy and Raman spectroscopy. The design of the presented planar waveguides was realized on the bases of modified dispersion equation and was schemed for 632.8 nm, 964 nm, 1 310 nm and 1 550 nm wavelengths. Waveguiding properties were examined by prism coupling technique and it was found that the diamond based planar optical element guided one fundamental mode for all measured wavelengths. Values of the refractive indices of our NCD thin film measured at various wavelengths were almost the same as those of natural diamond.

3D integration of planar crossbar memristive devices with CMOS substrate

International Nuclear Information System (INIS)

Lin, Peng; Pi, Shuang; Xia, Qiangfei

2014-01-01

Planar memristive devices with bottom electrodes embedded into the substrates were integrated on top of CMOS substrates using nanoimprint lithography to implement hybrid circuits with a CMOL-like architecture. The planar geometry eliminated the mechanically and electrically weak parts, such as kinks in the top electrodes in a traditional crossbar structure, and allowed the use of thicker and thus less resistive metal wires as the bottom electrodes. Planar memristive devices integrated with CMOS have demonstrated much lower programing voltages and excellent switching uniformity. With the inclusion of the Moiré pattern, the integration process has sub-20 nm alignment accuracy, opening opportunities for 3D hybrid circuits in applications in the next generation of memory and unconventional computing. (paper)

Heat dissipation in controlled environment enclosures through the application of water screens

Energy Technology Data Exchange (ETDEWEB)

Warrington, I.J.; Halligan, E.A.; Ruby, L.C.; McNaughton, K.G. [Horticulture and Food Research Institute of New Zealand Ltd., Palmerston North (New Zealand)

1994-12-31

The use of plate glass-water thermal barriers in controlled environment facilities effectively reduces the thermal load within the plant growth chamber. This allows high PPFs to be provided for plant growth and development studies, adequate simulation of daily light integrals, and simulation of peak PPFs. Further, substantial amounts of incandescent lamp supplementation can be used to achieve simulation of daylight R:FR ratios which are needed to ensure adequate stem development in some species. While the focus in this paper has been on the use of entire thermal barriers which separate the lighting enclosure from the plant growth chamber, the same principles apply to the use of water jackets for cooling individual lamps (such as can occur with xenon-arc lamps). In this instance, the barrier separating the lamps from the plant chamber can be much simpler (e.g., plexiglas) as the main function of the barrier is to separate the air ventilation of the lamp enclosure from the air system within the plant growth chamber. The main advantage of water as a thermal barrier is the negligible absorption of radiation in the photosynthetically-active and near infra-red wavebands. Consequently, plate glass-water barriers typically allow transmission of approximately 90% of radiation in these regions. While ventilated double and triple glazing systems appear to be attractive alternative to water barriers from an operating standpoint, their significant absorption in the biologically-important wavebands (7 - 12 %) with each glass layer and longer-wave cut-offs (typically 2500 - 4000 nm) makes them a much less attractive alternative. The data presented demonstrate clearly that measurement of PPF alone is not an adequate representation of the radiation environment being used in a controlled environment study.

The ATLAS Planar Pixel Sensor R and D project

International Nuclear Information System (INIS)

Beimforde, M.

2011-01-01

Within the R and D project on Planar Pixel Sensor Technology for the ATLAS inner detector upgrade, the use of planar pixel sensors for highest fluences as well as large area silicon detectors is investigated. The main research goals are optimizing the signal size after irradiations, reducing the inactive sensor edges, adjusting the readout electronics to the radiation induced decrease of the signal sizes, and reducing the production costs. Planar n-in-p sensors have been irradiated with neutrons and protons up to fluences of 2x10 16 n eq /cm 2 and 1x10 16 n eq /cm 2 , respectively, to study the collected charge as a function of the irradiation dose received. Furthermore comparisons of irradiated standard 300μm and thin 140μm sensors will be presented showing an increase of signal sizes after irradiation in thin sensors. Tuning studies of the present ATLAS front end electronics show possibilities to decrease the discriminator threshold of the present FE-I3 read out chips to less than 1500 electrons. In the present pixel detector upgrade scenarios a flat stave design for the innermost layers requires reduced inactive areas at the sensor edges to ensure low geometric inefficiencies. Investigations towards achieving slim edges presented here show possibilities to reduce the width of the inactive area to less than 500μm. Furthermore, a brief overview of present simulation activities within the Planar Pixel R and D project is given.

Planar-integrated single-crystalline perovskite photodetectors

KAUST Repository

Saidaminov, Makhsud I.

2015-11-09

Hybrid perovskites are promising semiconductors for optoelectronic applications. However, they suffer from morphological disorder that limits their optoelectronic properties and, ultimately, device performance. Recently, perovskite single crystals have been shown to overcome this problem and exhibit impressive improvements: low trap density, low intrinsic carrier concentration, high mobility, and long diffusion length that outperform perovskite-based thin films. These characteristics make the material ideal for realizing photodetection that is simultaneously fast and sensitive; unfortunately, these macroscopic single crystals cannot be grown on a planar substrate, curtailing their potential for optoelectronic integration. Here we produce large-area planar-integrated films made up of large perovskite single crystals. These crystalline films exhibit mobility and diffusion length comparable with those of single crystals. Using this technique, we produced a high-performance light detector showing high gain (above 104 electrons per photon) and high gain-bandwidth product (above 108 Hz) relative to other perovskite-based optical sensors.

Optical magnetism in planar metamaterial heterostructures.

Science.gov (United States)

Papadakis, Georgia T; Fleischman, Dagny; Davoyan, Artur; Yeh, Pochi; Atwater, Harry A

2018-01-18

Harnessing artificial optical magnetism has previously required complex two- and three-dimensional structures, such as nanoparticle arrays and split-ring metamaterials. By contrast, planar structures, and in particular dielectric/metal multilayer metamaterials, have been generally considered non-magnetic. Although the hyperbolic and plasmonic properties of these systems have been extensively investigated, their assumed non-magnetic response limits their performance to transverse magnetic (TM) polarization. We propose and experimentally validate a mechanism for artificial magnetism in planar multilayer metamaterials. We also demonstrate that the magnetic properties of high-index dielectric/metal hyperbolic metamaterials can be anisotropic, leading to magnetic hyperbolic dispersion in certain frequency regimes. We show that such systems can support transverse electric polarized interface-bound waves, analogous to their TM counterparts, surface plasmon polaritons. Our results open a route for tailoring optical artificial magnetism in lithography-free layered systems and enable us to generalize the plasmonic and hyperbolic properties to encompass both linear polarizations.

An O(n²) maximal planarization algorithm based on PQ-trees

NARCIS (Netherlands)

Kant, G.

1992-01-01

In this paper we investigate the problem how to delete a number of edges from a nonplanar graph G such that the resulting graph G’ is maximal planar, i.e., such that we cannot add an edge e E G – G’ to G’ without destroying planarity. Actually, our algorithm is a corrected and more generalized

OLED Fabrication by Using a Novel Planar Evaporation Technique

Directory of Open Access Journals (Sweden)

Fu-Ching Tung

2014-01-01

Full Text Available Organic light-emitting diode fabrication is suffering from extremely high material wasting during deposition especially using a typical point or even line source. Moreover, the need of depositing a high number of emitters and host(s with a precise composition control in a single layer makes traditional vapor codeposition systems nearly impossible, unless otherwise with a very low yield. To improve, we have developed a novel thin-film deposition system with a planar source loadable with any premetered solvent-mixed organic compounds, plausibly with no component number limitation. We hence demonstrate experimentally, along with a Monte Carlo simulation, in the report the feasibility of using the technique to deposit on a large area-size substrate various organic materials with a relatively high material utilization rate coupling with high film uniformity. Specifically, nonuniformity of less than ±5% and material utilization rate of greater than 70% have been obtained for the studied films.

A Twin Spiral Planar Antenna for UWB Medical Radars

Directory of Open Access Journals (Sweden)

Giuseppe A. Zito

2013-01-01

Full Text Available A planar-spiral antenna to be used in an ultrawideband (UWB radar system for heart activity monitoring is presented. The antenna, named “twin,” is constituted by two spiral dipoles in a compact structure. The reflection coefficient at the feed point of the dipoles is lower than −8 dB over the 3–12 GHz band, while the two-dipoles coupling is about −20 dB. The radiated beam is perpendicular to the plane of the spiral, so the antenna is wearable and it may be an optimal radiator for a medical UWB radar for heart rate detection. The designed antenna has been also used to check some hypotheses about the UWB radar heart activity detection mechanism. The radiation impedance variation, caused by the thorax vibrations associated with heart activity, seems to be the most likely explanation of the UWB radar operation.

Regular shock refraction in planar ideal MHD

International Nuclear Information System (INIS)

Delmont, P; Keppens, R

2010-01-01

We study the classical problem of planar shock refraction at an oblique density discontinuity, separating two gases at rest, in planar ideal (magneto)hydrodynamics. In the hydrodynamical case, 3 signals arise and the interface becomes Richtmyer-Meshkov unstable due to vorticity deposition on the shocked contact. In the magnetohydrodynamical case, on the other hand, when the normal component of the magnetic field does not vanish, 5 signals will arise. The interface then typically remains stable, since the Rankine-Hugoniot jump conditions in ideal MHD do not allow for vorticity deposition on a contact discontinuity. We present an exact Riemann solver based solution strategy to describe the initial self similar refraction phase. Using grid-adaptive MHD simulations, we show that after reflection from the top wall, the interface remains stable.

Planar Josephson tunnel junctions in a transverse magnetic field

DEFF Research Database (Denmark)

Monacoa, R.; Aarøe, Morten; Mygind, Jesper

2007-01-01

demagnetization effects imposed by the tunnel barrier and electrodes geometry are important. Measurements of the junction critical current versus magnetic field in planar Nb-based high-quality junctions with different geometry, size, and critical current density show that it is advantageous to use a transverse......Traditionally, since the discovery of the Josephson effect in 1962, the magnetic diffraction pattern of planar Josephson tunnel junctions has been recorded with the field applied in the plane of the junction. Here we discuss the static junction properties in a transverse magnetic field where...

Evaluated Rayleigh integrals for pulsed planar expanding ring sources

International Nuclear Information System (INIS)

Warshaw, S.I.

1985-01-01

Time-domain analytic and semianalytic pressure fields acoustically radiated from expanding pulsed ring sources imbedded in a planar rigid baffle have been calculated. The source functions are radially symmetric delta-function distributions whose amplitude and argument have simple functional dependencies on radius and time. Certain cases yield closed analytic results, while others result in elliptic integrals, which are evaluated to high accuracy by Gauss-Chebyshev and modified Gauss-Legendre quadrature. These results are of value for calibrating computer simulations and convolution procedures, and estimating fields from more complex planar radiators. 3 refs., 4 figs

KAPPEL Propeller. Development of a Marine Propeller with Non-planar Lifting Surfaces

DEFF Research Database (Denmark)

Kappel, J.; Andersen, Poul

2002-01-01

The principle of non-planar lifting surfaces is applied to the design of modern aircraft wings to obtain better lift to drag ratios. Whereas a pronounced fin or "winglet" at the wingtip has been developed for aircraft, the application of the non-planar principle to marine propellers, dealt...... with in this paper, has led to the KAPPEL propeller with blades curved towards the suction side integrating the fin or winglet into the propeller blade. The combined theoretical, experimental and practical approach to develop and design marine propellers with non-planar lifting surfaces has resulted in propellers...

Characterisation of the SmartPET planar Germanium detectors

Energy Technology Data Exchange (ETDEWEB)

Boston, H.C. [Department of Physics, University of Liverpool, Oliver Lodge Laboratory, Liverpool L69 7ZE (United Kingdom)], E-mail: H.C.Boston@liverpool.ac.uk; Boston, A.J.; Cooper, R.J.; Cresswell, J.; Grint, A.N.; Mather, A.R.; Nolan, P.J.; Scraggs, D.P.; Turk, G. [Department of Physics, University of Liverpool, Oliver Lodge Laboratory, Liverpool L69 7ZE (United Kingdom); Hall, C.J.; Lazarus, I. [CCLRC Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Berry, A.; Beveridge, T.; Gillam, J.; Lewis, R. [School of Physics and Materials Engineering, Monash University, Melbourne (Australia)

2007-08-21

Small Animal Reconstruction PET (SmartPET) is a project funded by the UK medical research council (MRC) to demonstrate proof of principle that Germanium can be utilised in Positron Emission Tomography (PET). The SmartPET demonstrator consists of two orthogonal strip High Purity Germanium (HPGe) planar detectors manufactured by ORTEC. The aim of the project is to produce images of an internal source with sub mm{sup 3} spatial resolution. Before this image can be achieved the detectors have to be fully characterised to understand the response at any given location to a {gamma}-ray interaction. This has been achieved by probing the two detectors at a number of specified points with collimated sources of various energies and strengths. A 1 mm diameter collimated beam of photons was raster scanned in 1 mm steps across the detector. Digital pulse shape data were recorded from all the detector channels and the performance of the detector for energy and position determination has been assessed. Data will be presented for the first SmartPET detector.