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Sample records for building enclosure hygrothermal

  1. Building Enclosure Hygrothermal Performance Study, Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Karagiozis, A.N.

    2002-08-08

    The moisture performance of three different classes of wall systems has been investigated in the context of the preliminary hygrothermal analysis of walls in Seattle. The results reported in this phase specifically address the moisture performance of walls designed with loads that have some unintentional water penetration. The results have been developed in a manner to present the relative performance of the walls in the same climate with similar water penetration effects. The analysis was performed with the best available input data. Several limitations should be recognized within the context of this study. Results showed that selection of wooden sheathing boards on interior vapor-tight assemblies does not significantly influence the performance of stucco-clad walls. A larger effect was observed when the interior vapor control is made vapor open. When continuous cavity ventilation is employed, the effect of the selection of the type of sheathing board on the hygrothermal performance of the wall was found to be negligible. When comparing oriented strand board sheathing performance against the performance of exterior grade gypsum, the differences are very significant in terms of the amount of moisture content present in the walls. Moisture content alone does not indicate their respective durability as durability is directly related to the combination of relative humidity and temperature, mechanical, chemical, and biological properties of the substrates. This study did not investigate the durability performance of either sheathing. In terms of interior vapor control, inhabitant behavior must be considered during the wall hygrothermal design stage. If interior relative humidity is maintained below 60%, then a latex primer and paint may perform better than the use of PVA or even a polyethylene sheet. When the interior environment is maintained at a higher relative humidity, then stricter vapor control is needed. Multilayered building paper was experimentally shown to

  2. Danish and Brazilian Modeling of Whole-Building Hygrothermal Performance

    DEFF Research Database (Denmark)

    Rode, Carsten; Mendes, Nathan; Grau, Karl

    2006-01-01

    computational analysis of the hygrothermal performance of whole buildings. Such developments have led to new hygrothermal models for whole buildings. The paper gives examples of two such recent developments and will illustrate some calculation results that can be obtained. Finally the paper will mention some......The humidity of rooms and moisture conditions of materials in the enclosure of buildings depend much on each other because of the moisture exchange that takes place over the interior surfaces. These moisture influences also depend strongly on the thermal conditions of indoor spaces and enclosure...... the humidity low and thus reduce the risk of moisture damage in the building enclosure. In either case the indoor humidity has a direct or indirect impact on the energy performance of the HVAC system of a building. To analyze this situation, one could benefit from some recent developments in integrated...

  3. Hygrothermal Behavior, Building Pathology and Durability

    CERN Document Server

    Delgado, JMPQ

    2013-01-01

    The main purpose of this book, Hygrothermal, Building Pathology and Durability, is to provide a collection of recent research works to contribute to the systematization and dissemination of knowledge related to construction pathology, hygrothermal behaviour of buildings, durability and diagnostic techniques and, simultaneously, to show the most recent advances in this domain. It includes a set of new developments in the field of building physics and hygrothermal behaviour, durability approach for historical and old buildings and building pathology vs. durability. The book is divided in several chapters that are a resume of the current state of knowledge for benefit of professional colleagues, scientists, students, practitioners, lecturers and other interested parties to network.

  4. Hygrothermal behavior, building pathology and durability

    Energy Technology Data Exchange (ETDEWEB)

    Peixoto de Freitas V.; Delgado, J.M.P.Q. (eds.) [Porto Univ. (Portugal). Building Physics Lab.

    2013-03-01

    Includes a set of new developments in the field of building physics and hygrothermal behavior. Presents a new durability approach for historical and old buildings. Reviews the current state of knowledge. The main purpose of this book, Hygrothermal, Building Pathology and Durability, is to provide a collection of recent research works to contribute to the systematization and dissemination of knowledge related to construction pathology, hygrothermal behaviour of buildings, durability and diagnostic techniques and, simultaneously, to show the most recent advances in this domain. It includes a set of new developments in the field of building physics and hygrothermal behaviour, durability approach for historical and old buildings and building pathology vs. durability. The book is divided in several chapters that are a resume of the current state of knowledge for benefit of professional colleagues, scientists, students, practitioners, lecturers and other interested parties to network.

  5. Whole-Building Hygrothermal Modeling in IEA Annex 41

    DEFF Research Database (Denmark)

    Rode, Carsten; Woloszyn, Monika

    2007-01-01

    . The IEA Annex 41 project runs from 2004–2007, coming to conclusion just before the Thermal Performance of the Exterior Envelopes of Whole Buildings X conference. The Annex 41 project and its Subtask 1 do not aim to produce one state-of-the-art hygrothermal simulation model for whole buildings, but rather...

  6. Hygrothermal Numerical Simulation Tools Applied to Building Physics

    CERN Document Server

    Delgado, João M P Q; Ramos, Nuno M M; Freitas, Vasco Peixoto

    2013-01-01

    This book presents a critical review on the development and application of hygrothermal analysis methods to simulate the coupled transport processes of Heat, Air, and Moisture (HAM) transfer for one or multidimensional cases. During the past few decades there has been relevant development in this field of study and an increase in the professional use of tools that simulate some of the physical phenomena that are involved in Heat, Air and Moisture conditions in building components or elements. Although there is a significant amount of hygrothermal models referred in the literature, the vast majority of them are not easily available to the public outside the institutions where they were developed, which restricts the analysis of this book to only 14 hygrothermal modelling tools. The special features of this book are (a) a state-of-the-art of numerical simulation tools applied to building physics, (b) the boundary conditions importance, (c) the material properties, namely, experimental methods for the measuremen...

  7. 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.

  8. Cold Climate Building Enclosure Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kosny, J.; Fallahi, A.; Shukla, N.

    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.

  9. Transient hygrothermal behaviour of a hemp concrete building envelope

    Energy Technology Data Exchange (ETDEWEB)

    Tran Le, A.D.; Maalouf, C.; Mai, T.H. [GRESPI/Thermomecanique, Universite de Reims, Moulin de la Housse BP. 1039, 51687 Reims (France); Wurtz, E. [INES-LOCIE, Savoie Technolac, Universite de Savoie, Le Bourget du Lac, 73375 Savoie (France); Collet, F. [Laboratoire de Genie civil et Genie Mecanique, equipe Materiaux-Thermo-Rheologie, Universite Europeenne de Bretagne, Rennes 1 (France)

    2010-10-15

    The sustainable world's economic growth and people's life improvement greatly depend on the use of alternative products in the architecture and construction, such as industrial wastes conventionally called green materials. For this purpose, hemp concrete is more and more recommended by the eco-builders because hemp is a renewable plant, recyclable and does not degrade within time. It corresponds perfectly to the requirements of high environmental quality buildings. The objective of this article is to study transient hygrothermal behaviour of hemp concrete at whole building level. The physical model is one-dimensional and was implemented into the object-oriented simulation environment SPARK, using the finite difference technique with an implicit scheme. The numerical result showed that the use of hemp concrete wall in buildings can ensure good indoor air quality and energy savings in winter. Besides, the combined effect of moisture buffering with the adequate ventilation strategies increases hemp concrete building performance. Our results also suggest that taking into account the hygrothermal transfer at whole building level with heat and moisture production sources has significant effects on predictions. (author)

  10. Hygrothermal Material Properties for Soils in Building Science

    Energy Technology Data Exchange (ETDEWEB)

    Kehrer, Manfred [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pallin, Simon B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-01-01

    Hygrothermal performance of soils coupled to buildings is complicated because of the dearth of information on soil properties. However they are important when numerical simulation of coupled heat and moisture transport for below-grade building components are performed as their temperature and moisture content has an influence on the durability of the below-grade building component. Soils can be classified by soil texture. According to the Unified Soil Classification System (USCA), 12 different soils can be defined on the basis of three soil components: clay, sand, and silt. This study shows how existing material properties for typical American soils can be transferred and used for the calculation of the coupled heat and moisture transport of building components in contact with soil. Furthermore a thermal validation with field measurements under known boundary conditions is part of this study, too. Field measurements for soil temperature and moisture content for two specified soils are carried out right now under known boundary conditions. As these field measurements are not finished yet, the full hygrothermal validation is still missing

  11. Whole-building Hygrothermal Simulation Model

    DEFF Research Database (Denmark)

    Rode, Carsten; Grau, Karl

    2003-01-01

    An existing integrated simulation tool for dynamic thermal simulation of building was extended with a transient model for moisture release and uptake in building materials. Validation of the new model was begun with comparison against measurements in an outdoor test cell furnished with single mat...

  12. Passive hygrothermal control of a museum storage building in Vejle

    DEFF Research Database (Denmark)

    Christensen, Jørgen Erik; Janssen, Hans

    2010-01-01

    and maintenance costs are currently motivating a paradigm change toward passive control. Passive control, via the thermal and hygric inertia of the building, is gaining a foothold in the museum conservation and building physical community. In this report we document the hygrothermal performance optimisation...... of a museum storage building, related to an existing storage centre in Vejle (Denmark). The current building design already incorporates passive control concepts: thermal inertia is provided by the thick walls, the ground floor and its underlying soil volume, while hygric inertia is provided by the thick...... purposes. Reduction of dehumidification load: In an effort to reduce the necessary dehumidification, a number of thermal measures are investigated first. This primarily focuses on the influences of additional insulation in walls, roof and floor. Overall, the effects of extra insulation on the average...

  13. Whole-building Hygrothermal Simulation Model

    DEFF Research Database (Denmark)

    Rode, Carsten; Grau, Karl

    2003-01-01

    An existing integrated simulation tool for dynamic thermal simulation of building was extended with a transient model for moisture release and uptake in building materials. Validation of the new model was begun with comparison against measurements in an outdoor test cell furnished with single...... materials. Almost quasi-steady, cyclic experiments were used to compare the indoor humidity variation and the numerical results of the integrated simulation tool with the new moisture model. Except for the case with chipboard as furnishing, the predictions of indoor humidity with the detailed model were...

  14. Hygrothermal analysis of a stabilised rammed earth test building in the UK

    Energy Technology Data Exchange (ETDEWEB)

    Allinson, David [Department of Civil and Building Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom); Hall, Matthew [Nottingham Centre for Geomechanics, Division of Materials, Mechanics and Structures, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

    2010-06-15

    This paper describes the analysis of the hygrothermal behaviours of stabilised rammed earth (SRE) walls used in a building in the UK. The analysis was achieved by computer simulation using WUFI Plus v1.2 whole building hygrothermal analysis software. To validate the model, an unoccupied test room in an unheated SRE building was monitored for 10 months. The hygrothermal properties of the SRE material were measured in the laboratory. It is shown that the SRE walls significantly reduced the amplitude of relative humidity fluctuations in the room air and reduced the frequency of high humidity periods at the wall surface. By adapting the model to represent an occupied and conditioned space, it is demonstrated that SRE walls have the potential to reduce the energy demand for humidification/dehumidification plant. (author)

  15. Implementation of Models for Building Envelope Air Flow Fields in a Whole Building Hygrothermal Simulation Tool

    DEFF Research Database (Denmark)

    Rode, Carsten; Grau, Karl

    2009-01-01

    Simulation tools are becoming available which predict the heat and moisture conditions in the indoor environment as well as in the envelope of buildings, and thus it has become possible to consider the important interaction between the different components of buildings and the different physical...... phenomena which occur. However, there is still room for further development of such tools. This paper will present an attempt to integrate modelling of air flows in building envelopes into a whole building hygrothermal simulation tool. Two kinds of air flows have been considered: 1. Air flow in ventilated...... cavity such as in the exterior cladding of building envelopes, i.e. a flow which is parallel to the construction plane. 2. Infiltration/exfiltration of air through the building envelope, i.e. a flow which is perpendicular to the construction plane. The new models make it possible to predict the thermal...

  16. Developing Innovative Wall Systems that Improve Hygrothermal Performance of Residential Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Robert Tichy; Chuck Murray

    2003-10-01

    This document serves as the Topical Report documenting the first year of work completed by Washington State University (WSU) under US Department of Energy Grant, Developing Innovative Wall Systems that Improve Hygrothermal Performance of Residential Buildings. This project is being conducted in collaboration with Oak Ridge National Laboratory (ORNL), and includes the participation of several industry partners including Weyerhaeuser Company, APA - The Engineered Wood Association, CertainTeed Corporation and Fortifiber. This document summarizes work completed by Washington State University August, 2002 through October, 2003. WSU's primary experimental role is the design and implementation of a field testing protocol that will monitor long term changes in the hygrothermal response of wall systems. In the first year WSU constructed a test facility, developed a matrix of test wall designs, constructed and installed test walls in the test facility, and installed instrumentation in the test walls. By the end of the contract period described in this document, WSU was recording data from the test wall specimens. The experiment described in this report will continue through December, 2005. Each year a number of reports will be published documenting the hygrothermal response of the test wall systems. Public presentation of the results will be made available to the building industry by industry partners and the University cooperators.

  17. Developing Innovative Wall Systems that Improve Hygrothermal Performance of Residential Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Robert Tichy; Chuck Murray

    2006-05-31

    This document serves as the Topical Report documenting work completed by Washington State University (WSU) under U.S. Department of Energy Grant, Developing Innovative Wall Systems that Improve Hygrothermal Performance of Residential Buildings. This project was conducted in collaboration with Oak Ridge National Laboratory (ORNL), and includes the participation of several industry partners including Weyerhaeuser, APA - The Engineered Wood Association, CertainTeed Corporation and Fortifiber. This document summarizes work completed by Washington State University August 2002 through June 2006. WSU's primary experimental role is the design and implementation of a field testing protocol that monitored long term changes in the hygrothermal response of wall systems. During the project period WSU constructed a test facility, developed a matrix of test wall designs, constructed and installed test walls in the test facility, installed instrumentation in the test walls and recorded data from the test wall specimens. Each year reports were published documenting the hygrothermal response of the test wall systems. Public presentation of the results was, and will continue to be, made available to the building industry at large by industry partners and the University.

  18. A Model for Air Flow in Ventilated Cavities Implemented in a Tool for Whole-Building Hygrothermal Analysis

    DEFF Research Database (Denmark)

    Grau, Karl; Rode, Carsten

    2006-01-01

    A model for calculating air flows in ventilated cavities has been implemented in the whole-building hygrothermal simulation tool BSim. The tool is able to predict indoor humidity conditions using a transient model for the moisture conditions in the building envelope.......A model for calculating air flows in ventilated cavities has been implemented in the whole-building hygrothermal simulation tool BSim. The tool is able to predict indoor humidity conditions using a transient model for the moisture conditions in the building envelope....

  19. Moisture buffering and its consequence in whole building hygrothermal modeling

    DEFF Research Database (Denmark)

    Rode, Carsten; Grau, Karl

    2008-01-01

    both. A new test method specifies a protocol for determination of what has recently been termed the Moisture Buffer Value (MBV) of building products. The paper presents the definition of MBV and introduces a test protocol which has been proposed for its experimental determination. The MBV is primarily...

  20. Towards energy efficient high-rise residential building enclosures: insight from energy bills and enclosure rehabilitations

    Energy Technology Data Exchange (ETDEWEB)

    Finch, Graham; Knowles, Warren; Ricketts, Lorne [RDH Building Engineering Ltd., Vancouver, (Canada)

    2010-07-01

    The building industry is looking to reduce energy consumption and the environmental impact of all building types. This paper investigated the relationship between current building practices and space heating in high-rise multi-unit residential buildings (MURBs). A summary of some of the key findings from a larger study with a focus on issues related to building enclosure conductive thermal losses was presented. This work involved the assessment of energy consumption data and, more specifically, of the space heating characteristics for mid and high-rise MURBs in the Lower Mainland of Vancouver which were selected as representative of typical MURB housing stock and included buildings with architectural forms common to other mid and high-rise residential buildings across North America. The effective R-value for all building enclosure assemblies for each building was calculated and compared with energy bills. The R-values were compared to ASHRAE 90.1. It was found that the overall effective R-values ranges were between R-2 and R-5 ft2 hr F/Btu.

  1. Effect of heat and moisture transport and storage properties of building stones on the hygrothermal performance of historical building envelopes

    Science.gov (United States)

    KoÅáková, Dana; Kočí, Václav; Žumár, Jaromír; Keppert, Martin; Holčapek, Ondřej; Vejmelková, Eva; Černý, Robert

    2016-12-01

    The heat and moisture transport and storage parameters of three different natural stones used on the Czech territory since medieval times are determined experimentally, together with the basic physical properties and mechanical parameters. The measured data are applied as input parameters in the computational modeling of hygrothermal performance of building envelopes made of the analyzed stones. Test reference year climatic data of three different locations within the Czech Republic are used as boundary conditions on the exterior side. Using the simulated hygric and thermal performance of particular stone walls, their applicability is assessed in a relation to the geographical and climatic conditions. The obtained results indicate that all three investigated stones are highly resistant to weather conditions, freeze/thaw cycles in particular.

  2. HYGRO-THERMAL BEHAVIOUR OF POROUS BUILDING MATERIAL SUBJECTED TO DIFFERENT EXTERNAL TEMPERATURE AND HUMIDITY CONDITIONS

    Directory of Open Access Journals (Sweden)

    ALI CHIKHI

    2016-04-01

    Full Text Available This work is focused on the behaviour of a block of cement mortar, subjected to variable external temperature and humidity conditions. The porous building material sample is fitted inside a box, in which a heat exchanger is connected to a thermostatic bath. Three sequences of measurement are considered: (i the response of the sample, when variations of temperature are applied; (ii the air ranging between the exchanger and the non-isolated face of the mortar is continuously humidified, by injecting of sprayed water; (iii the effect of simultaneously variation on temperature and humidity. A mathematical model representative of heat and mass transfer, in multiphasic medium (cement mortar, is developed in order to confront experimental and numerical results. Displacements of moisture and temperature fronts are observed and discussed. This study would enable us to understand the hygro-thermal behaviour of construction walls, to make an adequate design according to the climatic parameters and thus to improve the control of the energy used for heating.

  3. Natatorium Building Enclosure Deterioration Due to Moisture Migration

    Directory of Open Access Journals (Sweden)

    Aleka Pappas

    2012-12-01

    Full Text Available The natatorium enclosure at the Avon Recreation Center in Avon, Colorado experienced significant deterioration of the CMU façade due to moisture carried by humid air from the interior of the space into the wall assembly. This situation was caused by a combination of an insufficient interior air and vapor barrier along with an HVAC system that failed to provide negative pressurization to the space. This case study describes the investigation carried out to determine the causes of wall and roof deterioration at the building, and details the repair efforts undertaken. Lessons learned are presented to help designers, building owners, and maintenance personnel prevent similar problems from occurring in their buildings.

  4. Implementation of Models for Building Envelope Air Flow Fields in a Whole Building Hygrothermal Simulation Tool

    DEFF Research Database (Denmark)

    Sørensen, Karl Grau; Rode, Carsten

    2009-01-01

    Simulation tools are becoming available which predict the heat and moisture conditions in the indoor environment as well as in the envelope of buildings, and thus it has become possible to consider the important interaction between the different components of buildings and the different physical ...

  5. Integration of a hygrothermal transfer model for envelope in a building energy simulation model: experimental validation of a HAM-BES co-simulation approach

    Science.gov (United States)

    Ferroukhi, M. Y.; Abahri, K.; Belarbi, R.; Limam, K.

    2017-06-01

    The present paper focuses on studying a new methodology to predict the overall behavior of buildings, which combines two simulation tools: COMSOL Multiphysicsand TRNSYS. The first software is used for the modeling of heat, air and moisture transfer in multilayer porous walls (HAM model—Heat, Air and Moisture transfer), and the second is used to simulate the hygrothermal behavior of the building (BES model—Building Energy Simulation). The combined software applications dynamically solve the mass and energy conservation equations of the two physical models. In this context, a coupled heat, air and mass transfer model is proposed. This model incorporates simultaneously the diffusive, convective and conductive effects on the building elements. Heat transfer is considered in the strongly coupled situation where the mass and heat flux are temperature, vapor pressure and total pressure dependents. The model input parameters are evaluated experimentally through the development of various experimental prototypes in the laboratory. Thereafter, an experimental setup has been established in order to evaluate the hygrothermal process of building walls. The experimental procedure consists to follow the temperature and relative humidity evolutions within the envelope thickness, submitted to controlled and fixed boundary conditions. Finally, using the developed experimental device, comparison between experimental data and numerical solution of the HAM-BES co-simulation platform was undertaken. Results showed good agreement with acceptable errors margins.

  6. Integration of a hygrothermal transfer model for envelope in a building energy simulation model: experimental validation of a HAM-BES co-simulation approach

    Science.gov (United States)

    Ferroukhi, M. Y.; Abahri, K.; Belarbi, R.; Limam, K.

    2016-11-01

    The present paper focuses on studying a new methodology to predict the overall behavior of buildings, which combines two simulation tools: COMSOL Multiphysicsand TRNSYS. The first software is used for the modeling of heat, air and moisture transfer in multilayer porous walls (HAM model—Heat, Air and Moisture transfer), and the second is used to simulate the hygrothermal behavior of the building (BES model—Building Energy Simulation). The combined software applications dynamically solve the mass and energy conservation equations of the two physical models. In this context, a coupled heat, air and mass transfer model is proposed. This model incorporates simultaneously the diffusive, convective and conductive effects on the building elements. Heat transfer is considered in the strongly coupled situation where the mass and heat flux are temperature, vapor pressure and total pressure dependents. The model input parameters are evaluated experimentally through the development of various experimental prototypes in the laboratory. Thereafter, an experimental setup has been established in order to evaluate the hygrothermal process of building walls. The experimental procedure consists to follow the temperature and relative humidity evolutions within the envelope thickness, submitted to controlled and fixed boundary conditions. Finally, using the developed experimental device, comparison between experimental data and numerical solution of the HAM-BES co-simulation platform was undertaken. Results showed good agreement with acceptable errors margins.

  7. Hygrothermal analysis of characteristic public building rooms before energy efficient retrofitting solutions

    OpenAIRE

    Souaihi, Oussama; Capdevila, Roser; Lopez, Joan; Lehmkuhl Barba, Oriol; Rigola Serrano, Joaquim

    2016-01-01

    In the present paper, a modular, object-oriented and parallel methodology for the multiphysics simulation of buildings is presented. The whole building is modeled as a collection of basic elements (e.g., walls, rooms, outdoor, people, ventilation, solar radiation distributor, etc.). These elements can be modeled with different physical models and scales. A combined heat and moisture transfer model for the building envelopes and rooms have been implemented and validated with different benchmar...

  8. The impacts of green building strategies on the durability and performance of building enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Kernan, P. [RDH Building Engineering Ltd., Vancouver, BC (Canada)

    2007-07-01

    All buildings experience some level of failure during their lifetime. As such, it is to be expected that green buildings are likely to experience the same range of durability and building enclosure problems that affect conventional buildings, unless specific measures are taken. The author emphasized that when durability problems are identified in a green building, it is important to fully understand into which category the problems fall. This study used the Leadership in Energy and Environmental Design (LEED) rating system as a comparison framework for evaluating the environmental impact of green design strategies. LEED was also the focus of the study because of concerns that the processes involved in achieving LEED certification may themselves have negative impacts. Each of the following performance categories was reviewed in this paper: sustainable sites; water efficiency; energy and atmosphere; materials and resources; and, indoor environmental quality. The recommended design strategies to achieve each credit were also identified. It was concluded that the main problem in investigating durability issues in relation to green buildings is that so many of the buildings are new and relatively untested. The performance of these buildings will only become apparent over time. As such, ongoing monitoring and verification of performance is needed. 7 refs., 2 tabs., 1 fig.

  9. Hygrothermal evaluation of a museum storage building based on actual measurements and simulations

    DEFF Research Database (Denmark)

    Christensen, Jørgen Erik; Kollias, Christos Georgios

    2015-01-01

    environment facilities of a passive museum storage building in Vejle region in Denmark, are investigated. Results demonstrate that the weather conditions of the previous yearś considerably affect the indoor environment of the storage. What is more, concentrated dehumidification is a sufficient technique...

  10. Hygrothermal risk on building heritage a methodology for a risk map

    CERN Document Server

    Delgado, João M P Q; Freitas, Vasco Peixoto

    2015-01-01

    This book presents a critical review of a criterion of risk, created to assess the flood risk to heritage buildings, and evaluates this criterion by applying it to the sample Portuguese heritage buildings. In a first approach, the total number of potential parameters is effectively reduced and the selected criteria are divided into two different groups: the monument’s location in relation to a waterway, and the behaviour of its construction material in contact with water. Above all, the book discusses the importance of architectural heritage and argues for the need to safeguard it from extreme climatic phenomena such as floods. As such, the book vividly reminds the scientific community that the intensification of the global warming and climate change will worsen throughout the 21st century, and that it is therefore necessary to adopt preventive measures to minimize, mitigate and control these adverse effects if we hope to avoid catastrophic consequences. At the same time, the book takes into account a broad...

  11. Hygrothermal optimisation of museum storage spaces

    DEFF Research Database (Denmark)

    Janssen, Hans; Christensen, Jørgen Erik

    2013-01-01

    Despite the large economic and ecologic costs, museum storage spaces are often equipped with extensive air conditioning, to provide the desired stable interior climate. The new “passive conditioning” paradigm aims at resolving these costs: a high-hygrothermal-inertia building with a high-hygrothermal-resistance...... envelope is to satisfactorily stabilise that interior climate, with no need for mechanical air conditioning hence.This paper first studies the reliability of full passive conditioning for museum storage spaces. It is shown to be an illusion, since it usually results in excessive interior humidities....... Auxiliary dehumidification is thus required to provide good conservation conditions, and it is secondly investigated how the dehumidification load can be diminished. The study reveals the crucial impact of air tightness, while thermal insulation only has a minor influence.To further reduce the economic...

  12. 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

    , 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...

  13. Evaluating dynamic building materials: The potential impact of climatically responsive building enclosures

    Science.gov (United States)

    Kienzl, Nico H.

    Despite the great interest and investment in new material technologies and advanced simulation tools, predictions for the potential impact of dynamic envelope systems so far have been based on simulations of the overall building. However, overall building simulations provide limited insights into the behavior of the building envelope since results of these types of simulations are affected by many factors that are independent of or indirectly influenced by the building envelope. Therefore, it is difficult to isolate the impact of the building envelope on building energy consumption independent of building-specific factors such as building geometry, construction, environmental systems, and building use. In order to understand and quantify the dynamic nature of environmentally responsive envelope systems, designers and engineers necessitate a new method that enables the direct evaluation of only the envelope. This method needs to be able to predict the heat transfer through dynamic building envelopes under variable environmental conditions. Ultimately, this new method should help identify the applicability of new technologies early in the design process when detailed information on a building's design or operation are not yet available. This thesis establishes a new method and a validated reference case for the evaluation of climatically responsive building envelopes with dynamic material properties. The method isolates the performance of the building envelope in a building energy simulation model through transformation of a validated BESTEST model. It allows for parametric evaluation of the thermal performance of dynamic building envelopes under a wide range of environmental boundary conditions in comparison to existing reference technologies. This method can serve as a starting point for the critical evaluation of the impact that dynamic envelope systems have on the heat balance of buildings. The method was applied to the evaluation of electrochromic glazing to

  14. Hygrothermal rehabilitation of public buildings.A case study on “Luceafărul” theatre in Jassy

    Directory of Open Access Journals (Sweden)

    Adrian IACOB

    2014-07-01

    Full Text Available In the selection of thermo-energetic rehabilitation solutions, there are certain restrictions determined especially by the imperative of preserving the architectural characteristics, a large proportion of these buildings falling under the categories of historic or cultural monuments of high architectural value. Under the second category comes “Luceafărul” Theatre from Jassy, a representative edifice for the area in which it is located. The requirement of conserving the current appearance of the façade areas veneered with travertine has imposed the placing of thermal insulation on the interior surface. Taking into account that interior insulation implies a higher risk of interstitial condensation, a non-steady state coupled heat and mass transfer analysis was performed, by using the WUFI program. The results of this study are plotted as annual variations of relative humidity in the structure of envelope elements, pointing out the layers that are susceptible of excessive values. By numerical simulation of heat transfer with ANSYS program, the discussion is extended with the influence that the insulation of two adjacent envelope elements has on the surface condesation risk, for the case in which at the thermal bridge obtained there a discontinuity exists in the insulation layer.

  15. Hygrothermal Simulation of Foundations: Part 1 - Soil Material Properties

    Energy Technology Data Exchange (ETDEWEB)

    Kehrer, Manfred [ORNL; Pallin, Simon B [ORNL

    2012-10-01

    The hygrothermal performance of soils coupled to buildings is a complicated process. A computational approach for heat transfer through the ground has been well defined (EN ISO 13370:2007, 2007), and simplified methods have been developed (Staszczuk, Radon, and Holm 2010). However, these approaches generally ignore the transfer of soil moisture, which is not negligible (Janssen, Carmeliet, and Hens 2004). This study is divided into several parts. The intention of the first part is to gather, comprehend and adapt soil properties from Soil Science. The obtained information must be applicable to related tasks in Building Science and validated with hygrothermal calculation tools. Future parts of this study will focus on the validation aspect of the soil properties to be implemented. Basic changes in the software code may be requested at this time. Different types of basement construction will be created with a hygrothermal calculation tool, WUFI. Simulations from WUFI will be compared with existing or ongoing measurements. The intentions of the first part of this study have been fulfilled. The soil properties of interest in Building Science have been defined for 12 different soil textures. These properties will serve as input parameters when performing hygrothermal calculations of building constructions coupled to soil materials. The reliability of the soil parameters will be further evaluated with measurements in Part 2.

  16. Impact of wind-driven rain on historic brick wall buildings in a moderately cold and humid climate: Numerical analyses of mould growth risk, indoor climate and energy consumption

    DEFF Research Database (Denmark)

    Masaru, Abuku; Janssen, Hans; Roels, Staf

    2009-01-01

    response, mould growth at interior wall surfaces, indoor climate and energy consumption. First the WDR load oil the facades of a 4 m x 4 m x 10 m tower is determined. Then the hygrothermal behaviour of the brick walls is analysed oil a horizontal slice through the tower. The simulations demonstrate...... that WDR loads can have a significant impact on mould growth especially at the edges of the walls. Finally, for the case analysed, the WDR load Causes a significant increase of indoor relative humidity and energy consumption for heating. (C) 2008 Elsevier B.V. All rights reserved.......This paper gives an onset to whole building hygrothermal modelling in which the interaction between interior and exterior climates via building enclosures is simulated under a moderately cold and humid climate. The focus is particularly on the impact of wind-driven rain (WDR) oil the hygrothermal...

  17. Computational fluid dynamics modeling of mixed convection flows in buildings enclosures

    Directory of Open Access Journals (Sweden)

    Alexander Kayne, Ramesh K. Agarwal

    2013-01-01

    Full Text Available In recent years Computational Fluid Dynamics (CFD simulations are increasingly used to model the air circulation and temperature environment inside the rooms of residential and office buildings to gain insight into the relative energy consumptions of various HVAC systems for cooling/heating for climate control and thermal comfort. This requires accurate simulation of turbulent flow and heat transfer for various types of ventilation systems using the Reynolds-Averaged Navier-Stokes (RANS equations of fluid dynamics. Large Eddy Simulation (LES or Direct Numerical Simulation (DNS of Navier-Stokes equations is computationally intensive and expensive for simulations of this kind. As a result, vast majority of CFD simulations employ RANS equations in conjunction with a turbulence model. In order to assess the modeling requirements (mesh, numerical algorithm, turbulence model etc. for accurate simulations, it is critical to validate the calculations against the experimental data. For this purpose, we use three well known benchmark validation cases, one for natural convection in 2D closed vertical cavity, second for forced convection in a 2D rectangular cavity and the third for mixed convection in a 2D square cavity. The simulations are performed on a number of meshes of different density using a number of turbulence models. It is found that k-epsilon two-equation turbulence model with a second-order algorithm on a reasonable mesh gives the best results. This information is then used to determine the modeling requirements (mesh, numerical algorithm, turbulence model etc. for flows in 3D enclosures with different ventilation systems. In particular two cases are considered for which the experimental data is available. These cases are (1 air flow and heat transfer in a naturally ventilated room and (2 airflow and temperature distribution in an atrium. Good agreement with the experimental data and computations of other investigators is obtained.

  18. Computational fluid dynamics modeling of mixed convection flows in buildings enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Kayne, Alexander; Agarwal, Ramesh K. [Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130 (United States)

    2013-07-01

    In recent years Computational Fluid Dynamics (CFD) simulations are increasingly used to model the air circulation and temperature environment inside the rooms of residential and office buildings to gain insight into the relative energy consumptions of various HVAC systems for cooling/heating for climate control and thermal comfort. This requires accurate simulation of turbulent flow and heat transfer for various types of ventilation systems using the Reynolds-Averaged Navier-Stokes (RANS) equations of fluid dynamics. Large Eddy Simulation (LES) or Direct Numerical Simulation (DNS) of Navier-Stokes equations is computationally intensive and expensive for simulations of this kind. As a result, vast majority of CFD simulations employ RANS equations in conjunction with a turbulence model. In order to assess the modeling requirements (mesh, numerical algorithm, turbulence model etc.) for accurate simulations, it is critical to validate the calculations against the experimental data. For this purpose, we use three well known benchmark validation cases, one for natural convection in 2D closed vertical cavity, second for forced convection in a 2D rectangular cavity and the third for mixed convection in a 2D square cavity. The simulations are performed on a number of meshes of different density using a number of turbulence models. It is found that k-epsilon two-equation turbulence model with a second-order algorithm on a reasonable mesh gives the best results. This information is then used to determine the modeling requirements (mesh, numerical algorithm, turbulence model etc.) for flows in 3D enclosures with different ventilation systems. In particular two cases are considered for which the experimental data is available. These cases are (1) air flow and heat transfer in a naturally ventilated room and (2) airflow and temperature distribution in an atrium. Good agreement with the experimental data and computations of other investigators is obtained.

  19. Building America Case Study: Field Trial of an Aerosol-Based Enclosure Sealing Technology, Clovis, California

    Energy Technology Data Exchange (ETDEWEB)

    2016-05-01

    This report presents the results from several demonstrations of a new method for sealing building envelope air leaks using an aerosol sealing process developed by the Western Cooling Efficiency Center at UC Davis. The process involves pressurizing a building while applying an aerosol sealant to the interior. As air escapes through leaks in the building envelope, the aerosol particles are transported to the leaks where they collect and form a seal that blocks the leak. Standard blower door technology is used to facilitate the building pressurization, which allows the installer to track the sealing progress during the installation and automatically verify the final building tightness. Each aerosol envelope sealing installation was performed after drywall was installed and taped, and the process did not appear to interrupt the construction schedule or interfere with other trades working in the homes. The labor needed to physically seal bulk air leaks in typical construction will not be replaced by this technology. However, this technology is capable of bringing the air leakage of a building that was built with standard construction techniques and HERS-verified sealing down to levels that would meet DOE Zero Energy Ready Homes program requirements. When a developer is striving to meet a tighter envelope leakage specification, this technology could greatly reduce the cost to achieve that goal by providing a simple and relatively low cost method for reducing the air leakage of a building envelope with little to no change in their common building practices.

  20. Providing driving rain data for hygrothermal calculations

    DEFF Research Database (Denmark)

    Kragh, Mikkel Kristian

    1996-01-01

    Due to a wish for driving rain data as input for hygrothermal calculations, this report deals with utilizing commonly applied empirical relations and standard meteorological data, in an attempt to provide realistic estimates rather than exact correlations.......Due to a wish for driving rain data as input for hygrothermal calculations, this report deals with utilizing commonly applied empirical relations and standard meteorological data, in an attempt to provide realistic estimates rather than exact correlations....

  1. Substantiation of the simplified method of determining heat losses through underground parts of building enclosures

    Directory of Open Access Journals (Sweden)

    Samarin Oleg Dmitrievich

    2016-01-01

    Full Text Available Currently, the successful development of construction industry depends on the improved energy performance of buildings, structures and facilities, as well as on the quality assurance of the indoor climate. The approximate calculation of two-dimensional temperature field of the ground outside the underground part of the building is considered using the analytical solution of differential equation of thermal conduction by the method of sources and sinks according to the existing boundary conditions. This problem is a very high-priority task now because of actualization of building standards in Russian Federation and because of the increasing demands to safety and security of heat supply. That’s why it is very important to find a simple but accurate enough dependence for the heat losses through the floor situated on the ground. The results of the estimation of thermal resistance of floor areas on the ground are presented on the basis of the obtained temperature field. The comparison of these results with the regulatory requirements specified in SP 50.13330.2012, and with the data of numerical calculations of other authors using finite difference approximation of the thermal conduction equation with consideration of soil freezing is held. It is shown that the requirements of the SP 50.13330.2012 are physically reasonable, and numerical calculations can also be described by the analytical dependence obtained in this paper with appropriate selection of the numerical coefficients with the preservation of engineering form of the calculation procedure. The obtained model is easy to use in engineering practice especially during preliminary calculations. The presentation is illustrated with numerical and graphical examples.

  2. Material containment enclosure

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, D.O.

    1991-04-01

    An isolation enclosure and a group of isolation enclosures was designed which is useful when a relatively large containment area is required. The enclosure is in the form of a ring having a section removed so that a technician may enter the center area of the ring. in a preferred embodiment, an access zone is located in the transparent wall of the enclosure and extends around the inner perimeter of the ring so that a technician can insert his hands into the enclosure to reach any point within. The inventive enclosures provide more containment area per unit area of floor space than conventional material isolation enclosures.

  3. New object-oriented hygrothermal model library for calculating hygrothermal and hygienic comfort in rooms; Neue objektorientierte hygrothermische Modellbibliothek zur Ermittlung des hygrothermischen und hygienischen Komforts in Raeumen

    Energy Technology Data Exchange (ETDEWEB)

    Nouidui, Thierry; Sedlbauer, Klaus [Fraunhofer-Institut fuer Bauphysik (IBP), Institutsteil Holzkirchen, Valley (Germany); Nytsch-Geusen, Christoph [Universitaet der Kuenste Berlin (Germany). Fakultaet Gestaltung, Institut fuer Architektur und Staedtebau; Kiessl, Kurt [Fakulaet Architektur, Bauhaus-Universitaet Weimar (Germany)

    2009-10-15

    Developing energy-optimized ventilation strategies for moisture-related problems and the design and renovation of energy saving buildings requires an accurate knowledge of how hygrothermal components and buildings behave. These issues can be resolved with the aid of simulation tools before actually putting measurement technology into practice. The complexity of these issues produces complex models which can soon become unmanageable if suitable methods of description are not used. Due to their generic concepts such as class principle, inheritance principle, aggregation principle and polymorphism, modelling language standards such as Modelica enable complex systems such as these to be broken down into simple subsystems which can be verified and then reassembled. Research so far has lacked generic simulation tools for simulating components and buildings to enable a hygrothermal analysis with strong interactions between the behaviour of components, building envelope, building use and room conditions. Therefore the aim of this work was to develop a flexible, object-oriented, hygrothermal model library based on the Modelica modelling language for simulating and analysing the interactions between room conditions, the behaviour of components, building envelope and building use. This model library should be used for developing an energy-optimized ventilation system regulated according to demand in order to minimize the risk of mould forming while maintaining hygrothermal and hygienic comfort. The component and model library should be validated in example configurations in both simulations and trials. [German] Die Entwicklung energetisch optimierter Lueftungsstrategien fuer feuchtebedingte Probleme bzw. die Planung und die Sanierung energiesparender Gebaeude benoetigt eine genaue Kenntnis ueber das hygrothermische Bauteil- und Gebaeudeverhalten. Diese Fragestellungen koennen vor der eigentlichen messtechnischen Ausfuehrung mit Hilfe von Simulationstools beantwortet werden

  4. Long-term monitoring of the Sedlec Ossuary - Analysis of hygrothermal conditions

    Science.gov (United States)

    Pavlík, Zbyšek; Balík, Lukáš; Maděra, Jiří; Černý, Robert

    2016-07-01

    The Sedlec Ossuary is one of the twelve UNESCO World Heritage Sites in the Czech Republic. Although the ossuary is listed among the most visited Czech tourist attractions, its technical state is almost critical and a radical renovation is necessary. On this account, hygrothermal performance of the ossuary is experimentally researched in the presented paper in order to get information on moisture sources and to get necessary data for optimized design of renovation treatments and reconstruction solutions that will allow preserve the historical significance of this attractive heritage site. Within the performed experimental analysis, the interior and exterior climatic conditions are monitored over an almost three year period together with relative humidity and temperature profiles measured in the most damage parts of the ossuary chapel. On the basis of measured data, the long-term hygrothermal state of the ossuary building is accessed and the periods of possible surface condensation are identified.

  5. ANALYSIS OF HYGROTHERMAL CONDITIONS OF EXTERNAL PARTITIONS IN AN UNDERGROUND FRUIT STORE

    Directory of Open Access Journals (Sweden)

    Grzegorz Nawalany

    2016-09-01

    Full Text Available The paper presents the analysis of hygrothermal conditions of external partitions in an underground fruit store. The results of measurements of temperature and humidity of the indoor and outdoor air as well as the surface surrounding temperature and the temperature of the air surrounding the store constituted the boundary conditions for the hygrothermal calculations. The paper presents the calculation of the distribution of the temperature and humidity on the ground floor, the wall contacting the ground, the wall contacting the outside air, and the ceiling above the storage chamber. The heat and moisture calculations have shown high risk of condensation submerged in non-insulated external walls. The condition of the adaptation of a traditional cold store to a simple and atmosphere controlled cold one is to increase the thermal resistance of the partitions. Such a solution will let cut the energy demand in those types of agricultural buildings.

  6. Experimental Study on the Hygrothermal Behavior of a Coated Sprayed Hemp Concrete Wall

    Directory of Open Access Journals (Sweden)

    Anthony Magueresse

    2013-01-01

    Full Text Available Hemp concrete is a sustainable lightweight concrete that became popular in the field of building construction because of its thermal and environmental properties. However; available experimental data on its hygrothermal behavior are rather scarce in the literature. This paper describes the design of a large-scale experiment developed to investigate the hygrothermal behavior of hemp concrete cast around a timber frame through a spraying process; and then coated with lime-based plaster. The equipment is composed of two climatic chambers surrounding the tested wall. The experiment consists of maintaining the indoor climate at constant values and applying incremental steps of temperature; relative humidity or vapor pressure in the outdoor chamber. Temperature and relative humidity of the room air and on various depths inside the wall are continuously registered during the experiments and evaporation phenomena are observed. The influence of the plaster on the hygrothermal behavior of hemp concrete is investigated. Moreover; a comparison of experimental temperatures with numerical results obtained from a purely conductive thermal model is proposed. Comparing the model with the measured data gave satisfactory agreement.

  7. Hygrothermal Properties of Cross Laminated Timber and Moisture Response of Wood at High Relative Humidity

    Science.gov (United States)

    AlSayegh, George

    Cross Laminated Timber (CLT) is a new wood-based material composed of cross laminated wood boards that form a structural panel. This study focuses on identifying the appropriate methods to determine the hygrothermal properties of CLTs fabricated with Canadian and European Lumber. The laboratory tests carried out in this study will help establish heat, air and moisture response properties to be used for hygrothermal simulation to assess the durability of CLTs in building envelope construction. Measurement of water vapour permeability, liquid water absorption, sorption isotherms, thermal conductivity, and air permeability were performed on three Canadian CLT specimens composed of Hem-Fir, Eastern Spruce-Pine-Fir, and Western Spruce-Pine-Fir and one European specimen composed of Spruce. The hygrothermal properties of CLT, considered in this study, appear to be similar to commonly used wood specimens reported in the literature. However, liquid water absorption coefficients of CLT were found to be generally lower than common wood species, possibly due to the presence of glue between the wood layers which limits the moisture movement across the specimen. On the other hand, the air permeability across the CLT specimens varied due to the glue discontinuity within the specimen which led some CLTs to be permeable, however all the European specimens were found to be impermeable. This study also critically analyzed the significance of equilibrium moisture content (EMC) of wood at high relative humidity, measured by means of a pressure plate apparatus and humidity chambers, on the moisture management performance of a wood-frame stucco wall, using the hygrothermal simulation tool hygIRC-2D. The simulation results indicate that the prediction of the moisture response of a wood-frame stucco wall assembly depends significantly on the method adopted to derive the EMC of wood at high RH.

  8. 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)

  9. 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....

  10. 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....

  11. 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...

  12. 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...

  13. VIRUS instrument enclosures

    Science.gov (United States)

    Prochaska, T.; Allen, R.; Mondrik, N.; Rheault, J. P.; Sauseda, M.; Boster, E.; James, M.; Rodriguez-Patino, M.; Torres, G.; Ham, J.; Cook, E.; Baker, D.; DePoy, Darren L.; Marshall, Jennifer L.; Hill, G. J.; Perry, D.; Savage, R. D.; Good, J. M.; Vattiat, Brian L.

    2014-08-01

    The Visible Integral-Field Replicable Unit Spectrograph (VIRUS) instrument will be installed at the Hobby-Eberly Telescope† in the near future. The instrument will be housed in two enclosures that are mounted adjacent to the telescope, via the VIRUS Support Structure (VSS). We have designed the enclosures to support and protect the instrument, to enable servicing of the instrument, and to cool the instrument appropriately while not adversely affecting the dome environment. The system uses simple HVAC air handling techniques in conjunction with thermoelectric and standard glycol heat exchangers to provide efficient heat removal. The enclosures also provide power and data transfer to and from each VIRUS unit, liquid nitrogen cooling to the detectors, and environmental monitoring of the instrument and dome environments. In this paper, we describe the design and fabrication of the VIRUS enclosures and their subsystems.

  14. Accelerated hygrothermal stabilization of composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Gale, Jeffrey Alan [Univ. of California, Davis, CA (United States)

    1994-05-01

    Experimentation validated a simple moisture conditioning scheme to prepare Gr/Ep composite parts for precision applications by measuring dimensional changes over 90 days. It was shown that an elevated temperature moisture conditioning scheme produced a dimensionally stable part from which precision structures could be built/machined without significant moisture induced dimensional changes after fabrication. Conversely, that unconditioned Gr/Ep composite panels exhibited unacceptably large dimensional changes (i.e., greater than 125 ppM). It was also shown that time required to produce stable parts was shorter, by more than an order of magnitude, employing the conditioning scheme than using no conditioning scheme (46 days versus 1000+ days). Two final use environments were chosen for the experiments: 50% RH/21C and 0% RH/21C. Fiberite 3034K was chosen for its widespread use in aerospace applications. Two typical lay-ups were chosen, one with low sensitivity to hygrothermal distortions and the other high sensitivity: [0, ± 45, 90]s, [0, ± 15, 0]s. By employing an elevated temperature, constant humidity conditioning scheme, test panels achieved an equilibrium moisture content in less time, by more than an order of magnitude, than panels exposed to the same humidity environment and ambient temperature. Dimensional changes, over 90 days, were up to 4 times lower in the conditioned panels compared to unconditioned panels. Analysis of weight change versus time of test coupons concluded that the out-of-autoclave moisture content of Fiberite 3034K varied between 0.06 and 0.1%.

  15. Hygrothermal Properties and Performance of Sea Grass Insulation

    DEFF Research Database (Denmark)

    Eriksen, Marlene Stenberg Hagen; Laursen, Theresa Back; Rode, Carsten

    2008-01-01

    In the attempt to obtain knowledge of the hygrothermal properties of sea grass as thermal insulation, experiments have been carried out in the laboratory to determine the thermal conductivity, sorption properties and the water vapour permeability of the material. In order to investigate the hygro...

  16. Investigation of the Hygrothermal Performance of Alternative Insulation Materials

    DEFF Research Database (Denmark)

    Rode, Carsten; Kristiansen, Finn Harken; Rasmussen, Niels T.

    1999-01-01

    . The materials investigated are: cellulose insulation, sheep's wool, flax, and perlite. These materials, except for the last one, are very hygroscopic. The following two separate investigations are described.1. Investigation of the thermal conductivity at different humidity conditions.The thermal conductivity......The paper gives an account of hygrothermal investigations carried out on some insulation products which are "alternative" to the ones that are traditionally used in Danish constructions. The alternative products are claimed to be friendly both to the environment and to the labour force...... is determined for the different materials with a guarded hot plate apparatus in which different vapour pressure conditions can be maintained over the specimens. The apparatus and some results are presented.2. Computational analysis of the hygrothermal performance of constructions with alternative insulation...

  17. Investigation of the Hygrothermal Performance of Alternative Insulation Materials

    DEFF Research Database (Denmark)

    Rode, Carsten; Kristiansen, Finn Harken; Rasmussen, Niels T.

    1999-01-01

    products.The hygrothermal performance of constructions with alternative insulation products is analysed with a computational model for combined heat and moisture transfer. The analysis concerns both traditional wall and roof constructions with the alternative insulation products, and some alternative......The paper gives an account of hygrothermal investigations carried out on some insulation products which are "alternative" to the ones that are traditionally used in Danish constructions. The alternative products are claimed to be friendly both to the environment and to the labour force....... The materials investigated are: cellulose insulation, sheep's wool, flax, and perlite. These materials, except for the last one, are very hygroscopic. The following two separate investigations are described.1. Investigation of the thermal conductivity at different humidity conditions.The thermal conductivity...

  18. Hygrothermal modeling and testing of polymers and polymer matrix composites

    Science.gov (United States)

    Xu, Weiqun

    2000-10-01

    The dissertation, consisting of four papers, presents the results of the research investigation on environmental effects on polymers and polymer matrix composites. Hygrothermal models were developed that would allow characterization of non-Fickian diffusion coefficients from moisture weight gain data. Hygrothermal testing was also conducted to provide the necessary data for characterizing of model coefficients and model verification. In part 1, a methodology is proposed that would allow characterization of non-Fickian diffusion coefficients from moisture weight gain data for a polymer adhesive below its Tg. Subsequently, these diffusion coefficients are used for predicting moisture concentration profiles through the thickness of a polymer. In part 2, a modeling methodology based on irreversible thermodynamics applied within the framework of composite macro-mechanics is presented, that would allow characterization of non-Fickian diffusion coefficients from moisture weight gain data for laminated composites with distributed uniaxial damage. Comparisons with test data for a 5-harness satin textile composite with uniaxial micro-cracks are provided for model verifications. In part 3, the same modeling methodology based on irreversible thermodynamics is extended to the case of a bi-axially damaged laminate. The model allows characterization of nonFickian diffusion coefficients as well as moisture saturation level from moisture weight gain data for laminates with pre-existing damage. Comparisons with test data for a bi-axially damaged Graphite/Epoxy woven composite are provided for model verifications. Finally, in part 4, hygrothermal tests conducted on AS4/PR500 5HS textile composite laminates are summarized. The objectives of the hygrothermal tests are to determine the diffusivity and maximum moisture content of the laminate.

  19. Characterization of fracture toughness of epoxy resin after hygrothermal aging

    KAUST Repository

    Quispe, Gustavo Q.

    2013-07-01

    Characterization of fracture toughness of epoxy resin after hygrothermal ageing Gustavo Quino Quispe The aim of this work is to characterize the e ects of hygrothermal aging in the plain strain fracture toughness of the epoxy system composed by cycloaliphatic epoxy resin and diglycidyl ether of bisphenol-A (DGEBA). For this, after having been under hygrothermal aging in a climatic chamber, epoxy samples were studied using ASTM D5045 fracture toughness test, and micrography and roughness measurements of the fracture surface. It is reported a rapid decrease of GIc and KIc during the rst 2 days. Moreover, a numerical model [13] was used to simulate and see with more detail the water absorption in the aged samples. From that, it was observed the heterogeneous distribution of water. Accordingly, it was proposed that the results should be correlated with the water content at the vicinity of the crack tip. Consequently, it was possible to obtain, by quasi-static simulations, the ideal load-displacement curves of crack propagation in the heterogeneous samples. Finally, another contribution of this work is the study of the fracture surface, that gives a clue of the relationship among the fracture energy, the appearance of microcracks in the fracture surface, and the roughness (Ra).

  20. Experimental Study of the Hygrothermal Effect on Wear Behavior of Composite Materials

    Directory of Open Access Journals (Sweden)

    Fadhel Abbas. Abdulla

    2017-07-01

    Full Text Available The hygrothermal effect on the wear behavior of composite material (fiberglass and polyester resin vf=40% was investigated experimentally in this work. The study includes manufacturing of test device (pin on disc according to ASTM G 99. In order to study the hygrothermal effect on wear behavior of composite materials the hygrothermal chamber was manufactured. The experimental results show that the wear of glass fiber/polyester increased with increasing the load, sliding speed and sliding distance. The load and sliding distance were more effective on the wear of the composite rather than sliding speed. Also, it has been revealed that, the hygrothermal is considerable effect that, the wear rate of glass fiber/polyester without hygrothermal effect is lower than wear with hygrothermal effect. Applied load is the wear factor that has the highest physical influence on the wear of composites materials than other wear factors. Also, the wear of glass fiber/polyester without hygrothermal effect is lower than wear with hygrothermal effect.

  1. Introduction to Building Systems Performance: Houses that Work II. Revised February 2005

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-03-01

    The Building Science Consortium (BSC) design recommendations are based on the hygrothermal regions with reference to the annual rainfall. Local climate must be addressed if it differs significantly from the climate described for a particular design.

  2. Hygrothermal effect of bamboo by dynamic mechanical analysis

    Institute of Scientific and Technical Information of China (English)

    GUAN Mingjie; ZHANG Qisheng

    2006-01-01

    Dynamic properties of bamboo,Phyllostachys pubescens,with moisture content (MC) ranging from -130 to 130℃,were studied by dynamic mechanical analysis (DMA).The results showed that the hygrothermal effect on dynamic mechanical properties was negative.The storage modulus decreases with increasing temperature and MC,and glass transition temperature decreases with increasing MC.The glass transition temperature and tan delta of bamboo were 30.5℃,0.02 and 10.61℃,0.04,when MC was 10% and 34%,respectively.

  3. Hygrothermal Performance of West Coast Wood Deck Roofing System

    Energy Technology Data Exchange (ETDEWEB)

    Pallin, Simon B [ORNL; Kehrer, Manfred [ORNL; Desjarlais, Andre Omer [ORNL

    2014-02-01

    Simulations of roofing assemblies are necessary in order to understand and adequately predict actual the hygrothermal performance. At the request of GAF, simulations have been setup to verify the difference in performance between white and black roofing membrane colors in relation to critical moisture accumulation for traditional low slope wood deck roofing systems typically deployed in various western U.S. Climate Zones. The performance of these roof assemblies has been simulated in the hygrothermal calculation tool of WUFI, from which the result was evaluated based on a defined criterion for moisture safety. The criterion was defined as the maximum accepted water content for wood materials and the highest acceptable moisture accumulation rate in relation to the risk of rot. Based on the criterion, the roof assemblies were certified as being either safe, risky or assumed to fail. The roof assemblies were simulated in different western climates, with varying insulation thicknesses, two different types of wooden decking, applied with varying interior moisture load and with either a high or low solar absorptivity at the roof surface (black or white surface color). The results show that the performance of the studied roof assemblies differs with regard to all of the varying parameters, especially the climate and the indoor moisture load.

  4. Hygrothermal Performance of West Coast Wood Deck Roofing System

    Energy Technology Data Exchange (ETDEWEB)

    Pallin, Simon B [ORNL; Kehrer, Manfred [ORNL; Desjarlais, Andre Omer [ORNL

    2014-02-01

    Simulations of roofing assemblies are necessary in order to understand and adequately predict actual the hygrothermal performance. At the request of GAF, simulations have been setup to verify the difference in performance between white and black roofing membrane colors in relation to critical moisture accumulation for traditional low slope wood deck roofing systems typically deployed in various western U.S. Climate Zones. The performance of these roof assemblies has been simulated in the hygrothermal calculation tool of WUFI, from which the result was evaluated based on a defined criterion for moisture safety. The criterion was defined as the maximum accepted water content for wood materials and the highest acceptable moisture accumulation rate in relation to the risk of rot. Based on the criterion, the roof assemblies were certified as being either safe, risky or assumed to fail. The roof assemblies were simulated in different western climates, with varying insulation thicknesses, two different types of wooden decking, applied with varying interior moisture load and with either a high or low solar absorptivity at the roof surface (black or white surface color). The results show that the performance of the studied roof assemblies differs with regard to all of the varying parameters, especially the climate and the indoor moisture load.

  5. Surface Emissivity of Building Enclosure of Gas-fired Radiant Heating System Impact on the Indoor Thermal Environment%燃气辐射采暖围护结构内表面发射率对空间热环境的影响研究

    Institute of Scientific and Technical Information of China (English)

    张大英; 邹闻; 杨忠国

    2011-01-01

    在对物理模型合理简化的基础上,对燃气辐射供暖空间温度场的分布进行了模拟,指出不同的围护结构内表面发射率对空间温度场及系统能耗的影响,得出降低围护结构内表面发射率可强化燃气辐射供暖技术。%In this paper, in a simplified physical model based on a reasonable, gas-fired radiant heating on the temperature distribution in space has been simulated, and the influences of different surface emissivity of building enclosure to indoor temperature and energy consumption are pointed. The result shows: reducing surface emissivity of building enclosure can enhance gas-fired radiant heating technology.

  6. Discussion on energy saving technology of building envelop enclosure structure exterior%谈建筑围护结构外墙节能技术

    Institute of Scientific and Technical Information of China (English)

    刘晋凤

    2016-01-01

    介绍了建筑外墙结构的保温技术,论述了外墙外保温技术的优势,分析了聚苯板薄抹灰外墙外保温施工中的技术问题,总结出施工中的几点建议与技术措施,从而提高了建筑围护结构的节能水平,减少了资源浪费.%The paper introduced the thermal insulation technology of building exterior structure,discussed the advantages of external wall thermal insulation technology,analyzed the technical problems in polystyrene board external wall thermal insulation construction,summarized several sug-gestions and technical measures in construction,so as to improve the energy saving level of building exterior,reduced the resources waste.

  7. Safety of Hydrogen Systems Installed in Outdoor Enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Barilo, Nick F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-11-01

    The Hydrogen Safety Panel brings a broad cross-section of expertise from the industrial, government, and academic sectors to help advise the U.S. Department of Energy’s (DOE) Fuel Cell Technologies Office through its work in hydrogen safety, codes, and standards. The Panel’s initiatives in reviewing safety plans, conducting safety evaluations, identifying safety-related technical data gaps, and supporting safety knowledge tools and databases cover the gamut from research and development to demonstration and deployment. The Panel’s recent work has focused on the safe deployment of hydrogen and fuel cell systems in support of DOE efforts to accelerate fuel cell commercialization in early market applications: vehicle refueling, material handling equipment, backup power for warehouses and telecommunication sites, and portable power devices. This paper resulted from observations and considerations stemming from the Panel’s work on early market applications. This paper focuses on hydrogen system components that are installed in outdoor enclosures. These enclosures might alternatively be called “cabinets,” but for simplicity, they are all referred to as “enclosures” in this paper. These enclosures can provide a space where a flammable mixture of hydrogen and air might accumulate, creating the potential for a fire or explosion should an ignition occur. If the enclosure is large enough for a person to enter, and ventilation is inadequate, the hydrogen concentration could be high enough to asphyxiate a person who entered the space. Manufacturers, users, and government authorities rely on requirements described in codes to guide safe design and installation of such systems. Except for small enclosures used for hydrogen gas cylinders (gas cabinets), fuel cell power systems, and the enclosures that most people would describe as buildings, there are no hydrogen safety requirements for these enclosures, leaving gaps that must be addressed. This paper proposes that

  8. Experimental Study on Bond Behavior of FRP-Concrete Interface in Hygrothermal Environment

    Directory of Open Access Journals (Sweden)

    X. H. Zheng

    2016-01-01

    Full Text Available As the technique of fiber-reinforced polymer (FRP composite material strengthened reinforced concrete structures is widely used in the field of civil engineering, durability of the strengthened structures has attracted more attention in recent years. Hygrothermal environment has an adverse effect on the bond behavior of the interface between FRP and concrete. This paper focuses on the bond durability of carbon fiber laminate- (CFL- concrete interface in hygrothermal condition which simulates the climate characteristic in South China. Twenty 100 mm × 100 mm × 720 mm specimens were divided into 6 groups based on different temperature and humidity. After pretreatment in hygrothermal environment, the specimens were tested using double shear method. Strain gauges bonded along the CFL surface and linear variation displacement transducers (LVDTs were used to measure longitudinal strains and slip of the interface. Failure mode, ultimate capacity, load-deflection relationship, and relative slip were analyzed. The bond behavior of FRP-concrete interface under hygrothermal environment was studied. Results show that the ultimate bearing capacity of the interface reduced after exposure to hygrothermal environments. The decreasing ranges were up to 27.9% after exposure at high temperature and humidity (60°C, 95% RH. The maximum strains (εmax of the specimens pretreated decreased obviously which indicated decay of the bond behavior after exposure to the hygrothermal environment.

  9. Experimental investigation of cyclic hygrothermal aging of hybrid composite

    KAUST Repository

    El Yagoubi, Jalal

    2013-04-05

    This work provides an experimental investigation of the cyclic hygrothermal aging of a hybrid composites. We aimed to propose a general framework in the view to further optimize polymer-based composites. It reports experimental data and relevant observations collected during an aging campaign (up to 2000 cycles) where anhydride-cured epoxy samples as well as composites samples are exposed to environmental conditions. The data gathered during the whole campaign reveals that (1) the polymer displays a non-classical sorption behavior (2) the volume change is correlated to the mass uptake (3) the elastic modulus is correlated to the glass transition temperature. Matrix and interface degradation of the hybrid composite is monitored by means of microstructural observations. © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

  10. MODELLING THE PROCESSES OF HYGROTHERMAL MECHANICS IN RICE DRYING

    Directory of Open Access Journals (Sweden)

    S. A. Podgornyi

    2015-01-01

    Full Text Available Grain-crops are justly considered to be the staple food in Russia as well as all over the world. The specific feature is that postharvest processing of the grain and, above all, drying is an essential stage of providing products of high quality in the sufficient amount. The changes of the technological parameters of the drying process which take place over time, have a significant practical value in terms of monitoring the process and defining the modes providing the quality of the product as well as calculating energy demands necessary to carry out this process. Hereof, the quality of the product received is defined by minimum crack formation of rice grain after the process. The aim of the work is to get a mathematical model of hygrothermal mechanics of rice drying. On the basis of A.V. Lykov’s system of differential equations which describe the changes in moisture content, temperature and pressure, transition to the system of ordinary differential equations was offered which is based on drawing up balance of mass and heat during the process of drying. This approach does not consider the properties of moisture content and temperature within the material but takes into account their mean value. Using a simplified model of hygrothermal mechanics of rice drying that we have got enabled us to reproduce the process of drying in the conditions of minimum crack formation within the studied range (the temperature of the drying agent from 50 to 70 °C, speed from 2.3 to 2.8 м/sеk. The dependences we have got enable us to predict the quality of rice grain during drying.

  11. A Procedure to Measure the in-Situ Hygrothermal Behavior of Earth Walls

    Directory of Open Access Journals (Sweden)

    Pierre-Antoine Chabriac

    2014-04-01

    Full Text Available Rammed earth is a sustainable material with low embodied energy. However, its development as a building material requires a better evaluation of its moisture-thermal buffering abilities and its mechanical behavior. Both of these properties are known to strongly depend on the amount of water contained in wall pores and its evolution. Thus the aim of this paper is to present a procedure to measure this key parameter in rammed earth or cob walls by using two types of probes operating on the Time Domain Reflectometry (TDR principle. A calibration procedure for the probes requiring solely four parameters is described. This calibration procedure is then used to monitor the hygrothermal behavior of a rammed earth wall (1.5 m × 1 m × 0.5 m, instrumented by six probes during its manufacture, and submitted to insulated, natural convection and forced convection conditions. These measurements underline the robustness of the calibration procedure over a large range of water content, even if the wall is submitted to quite important temperature variations. They also emphasize the importance of gravity on water content heterogeneity when the saturation is high, as well as the role of liquid-to-vapor phase change on the thermal behavior.

  12. 46 CFR 154.195 - Aluminum cargo tank: Steel enclosure.

    Science.gov (United States)

    2010-10-01

    ... published in “Rules for Building and Classing Steel Vessels”, 1981. (c) The steel cover for the aluminum... 46 Shipping 5 2010-10-01 2010-10-01 false Aluminum cargo tank: Steel enclosure. 154.195 Section... CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction...

  13. Hygrothermal characterization of the viscoelastic properties of Gore-Select® 57 proton exchange membrane

    Science.gov (United States)

    Patankar, Kshitish A.; Dillard, David A.; Case, Scott W.; Ellis, Michael W.; Lai, Yeh-Hung; Budinski, Michael K.; Gittleman, Craig S.

    2008-09-01

    When a proton exchange membrane (PEM) based fuel cell is placed in service, hygrothermal stresses develop within the membrane and vary widely with internal operating environment. These hygrothermal stresses associated with hygral contraction and expansion at the operating conditions are believed to be critical in membrane mechanical integrity and durability. Understanding and accurately modeling the viscoelastic constitutive properties of a PEM is important for making hygrothermal stress predictions in the cyclic temperature and humidity environment of operating fuel cells. The tensile stress relaxation moduli of a commercially available PEM, Gore-Select® 57, were obtained over a range of humidities and temperatures. These tests were performed using TA Instruments 2980 and Q800 dynamic mechanical analyzers (DMA), which are capable of applying specified tensile loading conditions on small membrane samples at a given temperature. A special humidity chamber was built in the form of a cup that encloses tension clamps of the DMA. The chamber was inserted in the heating furnace of the DMA and connected to a gas humidification unit by means of plastic tubing through a slot in the chamber. Stress relaxation data over a temperature range of 40 90°C and relative humidity range of 30 90% were obtained. Thermal and hygral master curves were constructed using thermal and hygral shift factors and were used to form a hygrothermal master curve using the time temperature moisture superposition principle. The master curve was also constructed independently using just one shift factor. The hygrothermal master curve was fitted with a 10-term Prony series for use in finite element software. The hygrothermal master curve was then validated using longer term tests. The relaxation modulus from longer term data matches well with the hygrothermal master curve. The long term test showed a plateau at longer times, suggesting an equilibrium modulus.

  14. 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.

  15. 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.

  16. Performance of masonry enclosure walls: lessons learned from recent earthquakes

    Science.gov (United States)

    Vicente, Romeu Silva; Rodrigues, Hugo; Varum, Humberto; Costa, Aníbal; Mendes da Silva, José António Raimundo

    2012-03-01

    This paper discusses the issue of performance requirements and construction criteria for masonry enclosure and infill walls. Vertical building enclosures in European countries are very often constituted by non-load-bearing masonry walls, using horizontally perforated clay bricks. These walls are generally supported and confined by a reinforced concrete frame structure of columns and beams/slabs. Since these walls are commonly considered to be nonstructural elements and their influence on the structural response is ignored, their consideration in the design of structures as well as their connection to the adjacent structural elements is frequently negligent or insufficiently detailed. As a consequence, nonstructural elements, as for wall enclosures, are relatively sensitive to drift and acceleration demands when buildings are subjected to seismic actions. Many international standards and technical documents stress the need for design acceptability criteria for nonstructural elements, however they do not specifically indicate how to prevent collapse and severe cracking, and how to enhance the overall stability in the case of moderate to high seismic loading. Furthermore, a review of appropriate measures to improve enclosure wall performance and both in-plane and out-of-plane integrity under seismic actions is addressed.

  17. 50 CFR 14.151 - Primary enclosures.

    Science.gov (United States)

    2010-10-01

    ... 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... together may be shipped in the same primary enclosure. (c) A primary enclosure used to transport...

  18. 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...

  19. Combining building thermal simulation methods and LCA methods

    DEFF Research Database (Denmark)

    Pedersen, Frank; Hansen, Klaus; Wittchen, Kim Bjarne

    2008-01-01

    Thsi paper describes recent efforts made by the Danish Building Research Institute regarding the integration of a life cycle assessment (LCA) method into a whole building hygro-thermal simulation tool. The motivation for the work is that the increased requirements to the energy performance...

  20. Computation of mixing in large stably stratified enclosures

    Science.gov (United States)

    Zhao, Haihua

    This dissertation presents a set of new numerical models for the mixing and heat transfer problems in large stably stratified enclosures. Basing on these models, a new computer code, BMIX++ (Berkeley mechanistic MIXing code in C++), was developed by Christensen (2001) and the author. Traditional lumped control volume methods and zone models cannot model the detailed information about the distributions of temperature, density, and pressure in enclosures and therefore can have significant errors. 2-D and 3-D CFD methods require very fine grid resolution to resolve thin substructures such as jets, wall boundaries, yet such fine grid resolution is difficult or impossible to provide due to computational expense. Peterson's scaling (1994) showed that stratified mixing processes in large stably stratified enclosures can be described using one-dimensional differential equations, with the vertical transport by free and wall jets modeled using standard integral techniques. This allows very large reductions in computational effort compared to three-dimensional numerical modeling of turbulent mixing in large enclosures. The BMIX++ code was developed to implement the above ideas. The code uses a Lagrangian approach to solve 1-D transient governing equations for the ambient fluid and uses analytical models or 1-D integral models to compute substructures. 1-D transient conduction model for the solid boundaries, pressure computation and opening models are also included to make the code more versatile. The BMIX++ code was implemented in C++ and the Object-Oriented-Programming (OOP) technique was intensively used. The BMIX++ code was successfully applied to different types of mixing problems such as stratification in a water tank due to a heater inside, water tank exchange flow experiment simulation, early stage building fire analysis, stratification produced by multiple plumes, and simulations for the UCB large enclosure experiments. Most of these simulations gave satisfying

  1. Recent developments in building diagnosis techniques

    CERN Document Server

    2016-01-01

    This book presents a collection of recent research on building diagnosis techniques related to construction pathology, hygrothermal behavior and durability, and diagnostic techniques. It highlights recent advances and new developments in the field of building physics, building anomalies in materials and components, new techniques for improved energy efficiency analysis, and diagnosis techniques such as infrared thermography. This book will be of interest to a wide readership of professionals, scientists, students, practitioners, and lecturers.

  2. Numerical simulation of natural convection in a differentially heated tall enclosure using a spectral element method

    OpenAIRE

    Pitz, DB; Chew, JW

    2015-01-01

    Natural convection in differentially heated enclosures is a benchmark problem used to investigate the physics of buoyant flows and to validate numerical methods. Such configurations are also of interest in engineering applications such as cooling of electronic components and air flow around buildings. In this work a spectral element method is used to carry out direct numerical simulations of natural convection in a tall enclosure of aspect ratio 4 with isothermal vertical walls and adiabatic ...

  3. Moisture condensation on building envelopes in differential ventilated spaces in the tropics: quantitative assessment of influencing factors

    Directory of Open Access Journals (Sweden)

    Ali Maisarah

    2016-01-01

    Full Text Available Ventilation systems play a significant role in maintaining the indoor thermal and hygric balance. Nevertheless, the systems had been implicated to result in many problems. In the tropical climate, especially for energy efficiency purposes, building spaces are operated with differential ventilation. Such spaces operate on 24-hrs basis, some on 8-hrs while others are either naturally ventilated or served with mechanical supply-exhaust fan systems with non-conditioned outdoor air. This practice had been found to result in condensation problems. This study involves a quantitative appraisal of the effect of operative conditions and hygrothermal quality of building envelopes on condensation risk. The in-situ experiment is combined with an analytical approach to assessing the hygrothermal quality of building envelopes in a tropical climate building under differential ventilation between adjacent spaces. The case-studied building is with a known history of condensation and associated damages including mould growth. The microclimate measurement and hygrothermal performance of the wall and floor against condensation and mould growth risks had been previously reported elsewhere. As a step further, the present study evaluates the effects of various envelope insulation types and configurations together with the HVAC cooling set-points on envelope hygrothermal performance. The results revealed that overcooling the air-conditioned side increases condensation risk on the non-air-conditioned side of the envelopes. The envelopes failed criteria for surface condensation at existing operative conditions irrespective of envelope hygrothermal quality improvements. However, the envelope performed well at improved cooling operative conditions even at existing envelope hygrothermal quality. It is, therefore, important to ascertain the envelope hygrothermal quality as well the cooling operative conditions while embarking on energy efficiency operations in mechanical

  4. 33 CFR 127.709 - Protective enclosures.

    Science.gov (United States)

    2010-07-01

    ...) WATERFRONT FACILITIES WATERFRONT FACILITIES HANDLING LIQUEFIED NATURAL GAS AND LIQUEFIED HAZARDOUS GAS Waterfront Facilities Handling Liquefied Natural Gas Security § 127.709 Protective enclosures. The...

  5. Combining building thermal simulation methods and LCA methods

    OpenAIRE

    Pedersen, Frank; Hansen, Klaus; Wittchen, Kim Bjarne; Sørensen, Karl Grau; Johnsen, Kjeld

    2008-01-01

    Thsi paper describes recent efforts made by the Danish Building Research Institute regarding the integration of a life cycle assessment (LCA) method into a whole building hygro-thermal simulation tool. The motivation for the work is that the increased requirements to the energy performance of buildings (as expressed in EU Directive 2002/91/EC), may in the future be supplemented by requirements to the environmental impact of buildings. This can be seen by the fact that EU recently has given EN...

  6. Combined heat and moisture transfer in buildings systems

    OpenAIRE

    Damle, Rashmin; Lehmkuhl Barba, Oriol; Rigola Serrano, Joaquim; Oliva Llena, Asensio

    2012-01-01

    Temperature and humidity are the two main parameters indicating the comfort level of the building occupants. Although the effect of temperature is taken into account in thermal simulation of buildings, the moisture transfer through the rooms and porous building walls is sometimes neglected. The level of humidity can give different sensations of thermal comfort. It is necessary to take into account both heat and moisture transport in and around buildings to predict the hygrothermal behavior of...

  7. Qualitative and quantitative assessment of interior moisture buffering by enclosures

    DEFF Research Database (Denmark)

    Janssen, Hans; Roels, Staf

    2009-01-01

    The significance of interior humidity in attaining sustainable, durable, healthy and comfortable buildings is increasingly recognised. Given their significant interaction, interior humidity appraisals need a qualitative and/or quantitative assessment of interior moisture buffering. While...... suggested protocols for the simple and fast measurement of the moisture buffer potential of interior elements allow qualitative assessment, none of these are currently dependable for a wide range of moisture production regimes. In response to these flaws, this paper introduces the production......-adaptive characterisation of the moisture buffer potential of interior elements and corroborates their superposition toward a room-enclosure moisture buffer potential. It is verified that this enables qualitative comparison of enclosures in relation to interior moisture buffering. It is moreover demonstrated that it forms...

  8. In plant partial noise enclosures for the mining industry

    Energy Technology Data Exchange (ETDEWEB)

    Kinevy, P.T.

    1993-10-01

    The Physical and Toxic Agents Division of the Mine Safety and Health Administration`s Pittsburgh Safety and Health Technology Center has conducted three joint noise control demonstrations at dry milling operations. These demonstrations were conducted on a rod mill, a roller mill, and a ball mill, in order to survey a representative sample of the more commonly utilized types of milling equipment. The noise control concept that was demonstrated involved the construction of partial enclosures surrounding the mills and then adding acoustical materials within the enclosures to absorb the build up of acoustical energy. The results of this work illustrate the feasibility of this concept, the physical principle of creating an acoustical shadow, and the ability to closely predict the amount of absorptive material required to reduce the noise levels so as to comply with the Code of Federal Regulations (CFR), Title 30.

  9. PROCEDURE FOR ESTIMATING PERMANENT TOTAL ENCLOSURE COSTS

    Science.gov (United States)

    The paper discusses a procedure for estimating permanent total enclosure (PTE) costs. (NOTE: 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 PTEs, enclosures that mee...

  10. Influence of the convective surface transfer coefficients on the Heat, Air, and Moisture (HAM) building performance

    DEFF Research Database (Denmark)

    Steskens, Paul Wilhelmus Maria Hermanus; Janssen, Hans; Rode, Carsten

    2009-01-01

    HAM conditions. The paper focuses on the influence of the interior surface heat and moisture transfer coefficients, and investigates its effect on the hygrothermal performance. The parameter study showed that the magnitude of the convective surface transfer coefficients have a relatively large......Current models to predict heat, air and moisture (HAM) conditions in buildings assume constant boundary conditions for the temperature and relative humidity of the neighbouring air and for the surface heat and moisture transfer coefficients. These assumptions may introduce errors in the predicted...... influence on the predicted hygrothermal conditions at the surface of a building component and on the heat and vapour exchange with the indoor environment....

  11. Cold Climate Foundation Retrofit Experimental Hygrothermal Performance. Cloquet Residential Research Facility Laboratory Results

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Louise F. [NorthernSTAR, St. Paul, MN (United States); Harmon, Anna C. [NorthernSTAR, St. Paul, MN (United States)

    2015-04-09

    This project was funded jointly by the National Renewable Energy Laboratory (NREL) and Oak Ridge National Laboratory (ORNL). ORNL focused on developing a full basement wall system experimental database to enable others to validate hygrothermal simulation codes. NREL focused on testing the moisture durability of practical basement wall interior insulation retrofit solutions for cold climates. The project has produced a physically credible and reliable long-term hygrothermal performance database for retrofit foundation wall insulation systems in zone 6 and 7 climates that are fully compliant with the performance criteria in the 2009 Minnesota Energy Code. These data currently span the period from November 10, 2012 through May 31, 2014 and are anticipated to be extended through November 2014. The experimental data were configured into a standard format that can be published online and that is compatible with standard commercially available spreadsheet and database software.

  12. Effects of Hygrothermal Cycling on the Chemical, Thermal, and Mechanical Properties of 862/W Epoxy Resin

    Science.gov (United States)

    Miller, Sandi G.; Roberts, Gary D.; Copa, Christine C.; Bail, Justin L.; Kohlman, Lee W.; Binienda, Wieslaw K.

    2011-01-01

    The hygrothermal aging characteristics of an epoxy resin were characterized over 1 year, which included 908 temperature and humidity cycles. The epoxy resin quickly showed evidence of aging through color change and increased brittleness. The influence of aging on the material s glass transition temperature (Tg) was evaluated by Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). The Tg remained relatively constant throughout the year long cyclic aging profile. The chemical composition was monitored by Fourier Transform Infrared Spectroscopy (FTIR) where evidence of chemical aging and advancement of cure was noted. The tensile strength of the resin was tested as it aged. This property was severely affected by the aging process in the form of reduced ductility and embrittlement. Detailed chemical evaluation suggests many aging mechanisms are taking place during exposure to hygrothermal conditions. This paper details the influence of processes such as: advancement of cure, chemical degradation, and physical aging on the chemical and physical properties of the epoxy resin.

  13. A unified formulation for dynamic analysis of nonlocal heterogeneous nanobeams in hygro-thermal environment

    Science.gov (United States)

    Ebrahimi, Farzad; Barati, Mohammad Reza

    2016-09-01

    In this article, combined effect of moisture and temperature on free vibration characteristics of functionally graded (FG) nanobeams resting on elastic foundation is investigated by developing various refined beam theories which capture shear deformation influences needless of any shear correction factor. The material properties of FG nanobeam are temperature dependent and change gradually along the thickness through the power-law model. Size-dependent description of the nanobeam is performed applying nonlocal elasticity theory of Eringen. Nonlocal governing equations of embedded FG nanobeam in hygro-thermal environment obtained from Hamilton's principle are solved analytically. To verify the validity of the developed theories, the results of the present work are compared with those available in the literature. The effects of various hygro-thermal loadings, elastic foundation, gradient index, nonlocal parameter, and slenderness ratio on the vibrational behavior of FG nanobeams modeled via various beam theories are explored.

  14. Chapel of cemetery church of all saints in Sedlec - Long-term analysis of hygrothermal conditions

    Science.gov (United States)

    Pavlík, Zbyšek; Balík, Lukáš; Kudrnáčová, Lucie; Maděra, Jiří; Černý, Robert

    2017-07-01

    In this paper, long-term monitoring of hygrothermal conditions of the chapel of the cemetery church of All Saints in Sedlec, Czech Republic is presented as a practical tool for evaluation of functional problems of the researched structure. Within the performed experimental tests, interior and exterior climatic conditions were monitored over one year period. Herewith, surface temperature of the chapel wall was measured. Exterior climatic data were collected using weather station Vantage Pro2 placed in church tower. In interior, precise combined relative humidity/temperature sensors were installed. Based on the accessed hygrothermal state of the inspected chapel and identified periods of possible surface condensation, service conditions of the chapel will be optimized in order to prevent extensive damage of historically valuable finishing and furnishing materials, paintings, plasters, and architectural ornaments.

  15. The Effect of Cyclic Hygrothermal Environment on Interlaminar Shear Strength (ilss) of CCF300/BMI Composite

    Science.gov (United States)

    Zhao, Yan; Luo, Yun-Feng; Duan, Yue-Xin; Du, Shan-Yi

    An experimental study was conducted to examine the effect of cyclic hygrothermal environment on the interfacial property of CCF300/BMI composites. The moisture weight and interlaminar shear strength of CCF300/BMI composites specimen of each stage during three absorption-desorption cyclical stages was investigated. The results showed the ILSS of composites after water absorption dramatically decreased, but it could make a comeback on the whole after removal of water.

  16. Long-term hygrothermal effects on damage tolerance of hybrid composite sandwich panels

    Science.gov (United States)

    Ishai, Ori; Hiel, Clement; Luft, Michael

    1995-01-01

    A sandwich construction, composed of hybrid carbon-glass fiber-reinforced plastic skins and a syntactic foam core, was selected as the design concept for a wind tunnel compressor blade application, where high damage tolerance and durability are of major importance. Beam specimens were prepared from open-edge and encapsulated sandwich panels which had previously been immersed in water at different temperatures for periods of up to about two years in the extreme case. Moisture absorption and strength characteristics, as related to time of exposure to hygrothermal conditions, were evaluated for the sandwich specimens and their constituents (skins and foam). After different exposure periods, low-velocity impact damage was inflicted on most sandwich specimens and damage characteristics were related to impact energy. Eventually, the residual compressive strengths of the damaged (and undamaged) beams were determined flexurally. Test results show that exposure to hygrothermal conditions leads to significant strength reductions for foam specimens and open-edge sandwich panels, compared with reference specimens stored at room temperature. In the case of skin specimens and for beams prepared from encapsulated sanwich panels that had previously been exposed to hygrothermal conditions, moisture absorption was found to improve strength as related to the reference case. The beneficial effect of moisture on skin performance was, however, limited to moisture contents below 1% (at 50 C and lower temperatures). Above this moisture level and at higher temperatures, strength degradation of the skin seems to prevail.

  17. Hygrothermal Fracture Analysis of Orthotropic Functionally Graded Materials Using Jk-Integral-Based Methods

    Directory of Open Access Journals (Sweden)

    Serra Topal

    2013-01-01

    Full Text Available This paper puts forward two different Jk-integral-based methods, which can be used to perform mixed-mode fracture analysis of orthotropic functionally graded materials subjected to hygrothermal stresses. The first method requires the evaluation of both components of Jk-integral, whereas the second method employs the first component J1 and the asymptotic crack tip displacement fields. Plane orthotropic hygrothermoelasticity is the basic theory behind the Jk-integral formulation, which is carried out by assuming that all material properties are functions of the spatial coordinates. Developed procedures are implemented by means of the finite element method and integrated into a general purpose finite element analysis software. Temperature and specific moisture concentration fields needed in the fracture analyses are also computed through finite element analysis. Each of the developed methods is utilized in conjunction with the superposition technique to calculate the hygrothermal fracture parameters. An inclined crack located in a hygrothermally loaded orthotropic functionally graded layer is examined in parametric analyses. Comparisons of the results generated by the proposed methods do indicate that both methods lead to numerical results of high accuracy and that the developed form of the Jk-integral is domain independent. Further results are presented so as to illustrate the influences of crack inclination angle, crack length, and crack location upon the modes I and II stress intensity factors.

  18. BUCKLING AND POSTBUCKLING OF LAMINATED THIN CYLINDRICAL SHELLS UNDER HYGROTHERMAL ENVIRONMENTS

    Institute of Scientific and Technical Information of China (English)

    沈惠申

    2001-01-01

    The influence of hygrothermal effects on the buckling and postbuckling of composite laminated cylindrical shells subjected to axial compression is investigated using a micro-to-macro-mechanical analytical model. The material properties of the composite are affected by the variation of temperature and moisture, and are based on a micromechanical model of a laminate. The governing equations are based on the classical laminated shell theory, and including hygrothermal effects. The nonlinear prebuckling deformations and initial geometric imperfections of the shell were both taken into account. A boundary layer theory of shell buckling was extended to the case of laminated cylindrical shells under hygrothermal environments, and a singular perturbation technique was employed to determine buckling loads and postbuckling equilibrium paths. The numerical illustrations concern the postbuckling behavior of perfect and imperfect, cross-ply laminated cylindrical shells under different sets of environmental conditiors. The influences played by temperature rise, the degree of moisture concentration, fiber volume fraction, shell geometric parameter, total number of plies, stacking sequences and initial geometric imperfections are studied.

  19. Laboratory testing of a building envelope segment based on cellular concrete

    Science.gov (United States)

    Fořt, Jan; Pavlík, Zbyšek; Černý, Robert

    2016-07-01

    Hygrothermal performance of a building envelope based on cellular concrete blocks is studied in the paper. Simultaneously, the strain fields induced by the heat and moisture changes are monitored. The studied wall is exposed to the climatic load corresponding to the winter climatic conditions of the moderate year for Prague. The winter climatic exposure is chosen in order to simulate the critical conditions of the building structure from the point of view of material performance and temperature and humidity loading. The evaluation of hygrothermal performance of a researched wall is done on the basis of relative humidity and temperature profiles measured along the cross section of the cellular concrete blocks. Strain gauges are fixed on the wall surface in expected orientation of the blocks expansion. The obtained results show a good hygrothermal function of the analyzed cellular concrete wall and its insignificant strain.

  20. Effects of carbon fiber surface characteristics on interfacial bonding of epoxy resin composite subjected to hygrothermal treatments

    Science.gov (United States)

    Li, Min; Liu, Hongxin; Gu, Yizhuo; Li, Yanxia; Zhang, Zuoguang

    2014-01-01

    The changes of interfacial bonding of three types of carbon fibers/epoxy resin composite as well as their corresponding desized carbon fiber composites subjecting to hygrothermal conditions were investigated by means of single fiber fragmentation test. The interfacial fracture energy was obtained to evaluate the interfacial bonding before and after boiling water aging. The surface characteristics of the studied carbon fiber were characterized using X-ray photoelectron spectroscopy. The effects of activated carbon atoms and silicon element at carbon fiber surface on the interfacial hygrothermal resistance were further discussed. The results show that the three carbon fiber composites with the same resin matrix possess different hygrothermal resistances of interface and the interfacial fracture energy after water aging can not recovery to the level of raw dry sample (irreversible changes) for the carbon fiber composites containing silicon. Furthermore, the activated carbon atoms have little impact on the interfacial hygrothermal resistance. The irreversible variations of interfacial bonding and the differences among different carbon fiber composites are attributed to the silicon element on the carbon fiber bodies, which might result in hydrolyzation in boiling water treatment and degrade interfacial hygrothermal resistance.

  1. LSST summit enclosure-facility design optimization using aero-thermal modeling

    Science.gov (United States)

    Sebag, J.; Vogiatzis, K.; Barr, J.; Neill, D.

    2012-09-01

    This paper describes Computational Fluid Dynamic (CFD) analyses combined with thermal analyses for modeling the effects of passive ventilation, enclosure-building configuration and topography on the optical performance of the Large Synoptic Survey Telescope (LSST). The primary purpose of the analyses was to evaluate the seeing contribution of the major enclosure-facility elements and to select the features to be adopted in the baseline design from among various configurations being explored by the LSST project and the contracted architectural design team. In addition, one of several simulations for different telescope orientations is presented including various wind-telescope relative azimuth angles. Using a post-processing analysis, the effects of turbulence and thermal variations within the airflow around the buildings and inside the telescope-enclosure configuration were determined, and the optical performance due to the thermal seeing along the optical path was calculated.

  2. Practical considerations for permanent total enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Worrall, M. [Amcec Adsorption Systems, Schaumburg, IL (United States)

    1997-12-31

    This paper considers some of the practical consideration of Permanent Total Enclosures (PTEs) for gravure printing facilities. In particular the dispersion of fugitive losses from the presses by thermal air currents generated by heat from the press dryers.

  3. Interaction Between Flow Elements in Large Enclosures

    DEFF Research Database (Denmark)

    Heiselberg, Per

    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 and if this influe......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...... 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...

  4. Building

    OpenAIRE

    Seavy, Ryan

    2014-01-01

    Building for concrete is temporary. The building of wood and steel stands against the concrete to give form and then gives way, leaving a trace of its existence behind. Concrete is not a building material. One does not build with concrete. One builds for concrete. MARCH

  5. Modeling Local Hygrothermal Interaction: Local surface transfer coefficients

    DEFF Research Database (Denmark)

    Steskens, Paul Wilhelmus Maria Hermanus; Janssen, Hans; Rode, Carsten

    2009-01-01

    Current models to predict heat, air and moisture (HAM) conditions in building components assume uniform boundary conditions, both for the temperature and relative humidity of the air in an indoor space as well as for the heat and moisture surface transfer coefficients. In order to obtain a reliable...... prediction of the HAM conditions in a building component, an accurate description of the indoor boundary conditions is required. This paper presents the modelling of the local indoor environmental conditions, using a (sub)zonal airflow model, focussing on the prediction of the local interior surface heat...

  6. Hygrothermal response of a dwelling house. Thermal comfort criteria

    Directory of Open Access Journals (Sweden)

    Adrian IACOB

    2015-12-01

    Full Text Available The use of local natural materials in order to reduce the environmental negative impact of buildings has become common practice in recent years; such buildings are to be found in all regions of the planet. The high level of thermal protection provided by the envelope elements made from natural materials such as straw bale insulation, hemp insulation or sheep wool, and their lack of thermal massiveness require a more complex analysis on their ability to keep interior comfort without accentuated variations. This paper proposes a comparative analysis between different solutions for a residential building located near a Romanian city, Cluj-Napoca. The elements of the building envelope are designed in three alternative solutions, using as substitute to classical solutions (concrete and polystyrene, masonry and polystyrene, straw bales and rammed earth for enclosing elements. For this purpose there are conducted numerical simulations of heat and mass transfer, using a mathematical model that allows the analysis of indoor comfort, by comparing both objective factors (air temperature, operative temperature and relative humidity and subjective factors, which are needed to define interior thermal comfort indices PPD and PMV. Finally, a set of conclusions are presented and future research directions are drawn.

  7. 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.

  8. Thermal Stability Influence of the Enclosure Structure on the Building’s Energy Efficiency

    Directory of Open Access Journals (Sweden)

    Zaborova Daria

    2016-01-01

    Full Text Available Thermal stability of the enclosure structures is one of the most important objective in the building design. Thermal processes in the wall depend not only on the internal and external air temperature, but also on many other factors. Therefore, complexity of this process make heat conservation in the room to be an actual problem. This paper presents dependence between thermal stability of the enclosure structure and its design. It was shown that thermophysical characteristics of materials directly affect the thermal processes in the wall. For the research, three frequently used types of enclosure structure in Russia were taken. For each wall was found the average temperature and cooling time. As a result, it was found that the higher values of thermal conductivity, specific heat and material density are, the higher average temperature of the wall is.

  9. 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.

  10. 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.

  11. Cold Climate Foundation Retrofit Experimental Hygrothermal Performance: Cloquet Residential Research Facility Laboratory Results

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Louise F. [NorthernSTAR, St. Paul, MN (United States); Harmon, Anna C. [NorthernSTAR, St. Paul, MN (United States)

    2015-04-01

    Thermal and moisture problems in existing basements create a unique challenge because the exterior face of the wall is not easily or inexpensively accessible. This approach addresses thermal and moisture management from the interior face of the wall without disturbing the exterior soil and landscaping. the interior and exterior environments. This approach has the potential for improving durability, comfort, and indoor air quality. This project was funded jointly by the National Renewable Energy Laboratory (NREL) and Oak Ridge National Laboratory (ORNL). ORNL focused on developing a full basement wall system experimental database to enable others to validate hygrothermal simulation codes. NREL focused on testing the moisture durability of practical basement wall interior insulation retrofit solutions for cold climates. The project has produced a physically credible and reliable long-term hygrothermal performance database for retrofit foundation wall insulation systems in zone 6 and 7 climates that are fully compliant with the performance criteria in the 2009 Minnesota Energy Code. The experimental data were configured into a standard format that can be published online and that is compatible with standard commercially available spreadsheet and database software.

  12. Managing the system validation of the DKIST enclosure

    Science.gov (United States)

    Ariño, Javier; Gómez, Celia; Murga, Gaizka; Ampuero, Pedro; Campo, Ramon

    2014-08-01

    The size of the DKIST (formerly ATST) Enclosure, similar to the 8-10 meters class telescopes such as VLT or GTC, together with the strict and demanding requirement of using the azimuth and shutter movement for accurate positioning of the entrance aperture stop while tracking, makes it probably the most complex enclosure built up to date. Thus, managing the system validation becomes a challenging task, in which the singularity of this system has to be considered by applying customized tools and processes in addition to the usual procedures. This paper describes the managing process followed towards DKIST Enclosure validation, focused on ensuring final on-site assembly and performance. During the design phase, the system verification was carried out by means of modeling tools and detailed simulations and calculations. Furthermore, an overall BIM (Building Information Model) was built to integrate all the design work and detect potential problems since the design phase; it was used to check interfaces between subsystems, verify accessibility for maintenance and study the construction process. The Factory Assembly and Testing phase (FA&T) test campaign, recently finished, has been oriented towards the final system validation, by testing: 1) the overall system integration; 2) the performance; 3) the simulation of the final on-site assembly. The importance of guaranteeing a correct on-site assembly has driven also the decision towards the installation of a modular prefabricated cladding, which reduces the risk inherent to the site remoteness and the on-site installation of the outer water-cooled skin. The validation process also included early prototyping and testing of critical subsystems. That being said, all this helps reducing the risk significantly during the final on-site assembly and commissioning through the replication of already validated procedures.

  13. Selecting Eco-Friendly Thermal Systems for the “Vittoriale Degli Italiani” Historic Museum Building

    Directory of Open Access Journals (Sweden)

    Davide Astiaso Garcia

    2015-09-01

    Full Text Available Thermal systems installed in museums should guarantee the maintenance of the optimal hygrothermal parameters ranges for the conservation of their collection materials. Considering the preservation of historic buildings, according to their historical and landscaping constraints, not all the thermal system typologies could be installed in these buildings’ typologies. Therefore, the main aim of this paper is to present some indications for the choice of the best thermal system solutions for a considered historic museum building, called Vittoriale degli Italiani, in the north of Italy, taking into account their installation feasibility and their related environmental impacts. The methodology includes a monitoring of the current hygrothermal parameters as well as the assessment of design heat and cooling loads related to the maintenance of the optimal hygrothermal parameters ranges for the conservation of collection materials. In addition, a Life Cycle Assessment (LCA of each selected system typology is considered for highlighting the most eco-friendly solution among the suitable ones. The obtained results highlights the feasible thermal system solutions able to maintain the hygrothermal parameters between the optimal ranges with a lower environmental impact in the Vittoriale degli Italiani historic museum building.

  14. Measurement of Moisture in Wood for Application in the Restoration of Old Buildings

    OpenAIRE

    Carlos Moron; Luisa Garcia-Fuentevilla; Alfonso Garcia; Alberto Moron

    2016-01-01

    There are many historic buildings whose construction is based on timber frame walls. Most buildings built during the nineteenth and early twentieth centuries were based on timber frame walls with vertical support elements. These timber frame elements are affected by their moisture content and by the passage of time. If the interaction of the timber frame walls with hygrothermal fluctuations were known, the maintenance of these buildings could be improved significantly. To determine the moistu...

  15. Ditched enclosures in Southern Portugal: an Archaeoastronomical view

    Science.gov (United States)

    Mejuto, A J.; Valera, A. Carlos; Castaño, J. Gómez; Rodríguez-Caderot, G.; Becker, Helmut

    2015-05-01

    Since the very first ages, human beings have attempted to understand and manage their environment in order to survive. This is the case regarding wildlife, weather cycles and gathering periods. This is also reflected in the areas surrounding sites where individuals live; they changed the landscape with different aims. This type of archaeology has risen very recently - in the last few years - and is usually called Landscape Archaeology. Traditional landscape archaeology has dealt with earth and location related studies; the relationship of ancient peoples with the sky has been disregarded. The archaeoastronomical studies have mitigated this fact. Archaeoastronomy has revealed an important number of archaeological sites; many of them reveal a clear intention of astronomically designed buildings or structures. This implies a planned detailed design and obviously a deep understanding of astronomical knowledge. As examples of these sites a number of megalithic ditched enclosures sited in Portugal will be shown which were studied inside the project "Ditched enclosures plants and Neolithic cosmologies: A landscape, archaeoastronomical and geophysical perspective". The ideological and astronomical aspects inside the architecture of these types of sites will be explained. In this paper we present a new methodology applied in the archaeoastronomical calculations for southern Portugal sites. It includes GIS techniques and the development of an archaeoastronomical layer that can be used to display the computations over cartographic information from the archaeological sites. A Spatial Data Infrastructure is also created in order to expose the results.

  16. 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...

  17. 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...

  18. 9 CFR 3.53 - Primary enclosures.

    Science.gov (United States)

    2010-01-01

    ... used at research facilities when approved by the Institutional Animal Care and Use Committee, and by... 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...

  19. 9 CFR 3.6 - Primary enclosures.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Primary enclosures. 3.6 Section 3.6 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ANIMAL WELFARE STANDARDS Specifications for the Humane Handling, Care, Treatment, and Transportation of Dogs...

  20. 9 CFR 3.28 - Primary enclosures.

    Science.gov (United States)

    2010-01-01

    ... Animal Care and Use Committee, and by dealers and exhibitors when approved by the Administrator. Animal... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Primary enclosures. 3.28 Section 3.28 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

  1. 9 CFR 3.80 - Primary enclosures.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Primary enclosures. 3.80 Section 3.80 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ANIMAL WELFARE STANDARDS Specifications for the Humane Handling, Care, Treatment, and Transportation of...

  2. Cask Processing Enclosure Specification/Operation - 12231

    Energy Technology Data Exchange (ETDEWEB)

    Gentry, Ronald [Transuranic Waste Processing Center, Lenoir City TN, 37771 (United States)

    2012-07-01

    Following an evaluation of throughput rates in the Hot Cell at the Transuranic Waste Processing Center and considering the variability in the waste with respect to actual dose rates a new approach to processing transuranic waste was necessary. Compounding the issue was the remote equipment poor reliability and high down-time. After considering all the factors, the evaluation resulted in the design and construction of a new waste processing area for handling the concrete casks that predominately contain contact handled transuranic (TRU) waste. The area is called the Cask Processing Enclosure and essentially the Cask Processing Enclosure mimics the projects current process techniques used for processing Contact Handled -TRU waste in the existing Box Breakdown Area and Glovebox. The Cask Processing Enclosure approach was developed based on a review of the RH processing throughput rates in the Hot Cell. As the process was reviewed consideration was given to the variability in the waste with respect to actual dose rates and the lack of equipment reliability and high wear in the Hot Cell. Based on that review, a new contact handled processing area for handling the concrete casks is being constructed and startup is expected shortly following WM2012. The Cask Processing Enclosure essentially mimics the projects current process techniques used for processing Contact Handled waste in the existing Box Breakdown Area and Glovebox and the design takes into consideration six years of operational experience. (authors)

  3. Moisture Dynamics in Building Envelopes

    DEFF Research Database (Denmark)

    Peuhkuri, Ruut Hannele

    2003-01-01

    The overall scope of this Thesis "Moisture dynamics in building envelopes" has been to characterise how the various porous insulation materials investigated performed hygrothermally under conditions similar to those in a typical building envelope. As a result of the changing temperature and moist......The overall scope of this Thesis "Moisture dynamics in building envelopes" has been to characterise how the various porous insulation materials investigated performed hygrothermally under conditions similar to those in a typical building envelope. As a result of the changing temperature...... and moisture conditions in the exterior weather and indoor climate the materials dynamically absorb and release moisture. The complexity of the impact of these conditions on the resulting moisture transport and content of the materials has been studied in this Thesis with controlled laboratory tests. The first...... part of the Thesis consists of a theory and literature review on the moisture storage and transport processes (Chapter 2), on the non-Fickian moisture transport (Chapter 3)and on the methods for determining the moisture properties (Chapter 4). In the second part, the conducted experimental work...

  4. Investigating dynamic response of porous inhomogeneous nanobeams on hybrid Kerr foundation under hygro-thermal loading

    Science.gov (United States)

    Barati, Mohammad Reza

    2017-05-01

    This paper is concerned with the forced vibration analysis of imperfect functionally graded (FG) nanobeams resting on three-parameter Kerr foundation under hygro-thermal loading employing a higher order refined beam theory. The nanobeam is subjected to dynamic uniform distributed and concentrated point loads at upper surface. Hygro-thermo-elastic material properties of FGM nanobeam vary in thickness direction according to the power-law distribution. Implementing an analytical approach, the obtained nonlocal coupled governing equations from Hamilton's principle according to refined beam model are solved for simply supported and clamped boundary conditions. The significance of moisture percentage, temperature change, material gradation, scale parameter, Kerr foundation coefficients and boundary conditions on forced vibration characteristics and resonance frequencies of FG nanobeam are examined.

  5. Impact of coupled heat and moisture transfer effects on buildings energy consuption

    Directory of Open Access Journals (Sweden)

    Ferroukhi Mohammed Yacine

    2017-01-01

    Full Text Available Coupled heat, air, and moisture transfers through building envelope have an important effect on prediction of building energy requirements. Several works were conducted in order to integrate hygrothermal transfers in dynamic buildings simulations codes. However, the incorporation of multidirectional hygrothermal transfer analysis in the envelope into building simulation tools is rarely considered. In this work, coupled heat, air, and moisture (HAM transfer model in multilayer walls was established. Thereafter, the HAM model is coupled dynamically to a building behavior code (BES.The coupling concerns a co-simulation between COMSOL Multiphysics and TRNSYS software. Afterward, the HAM-BES co-simulation accuracy was verified. Then, HAM-BES co-simulation platform was applied to a case study with various types of climates (temperate, hot and humid, cold and humid. Three simulations cases were carried out. The first simulation case consists of the TRNSYS model without HAM transfer model. The second simulation case, 1-D HAM model for the envelope was integrated in TRNSYS code. For the third one, 1-D HAM model for the wall and 2-D HAM model for thermal bridges were coupled to the thermal building model of TRNSYS. Analysis of the results confirms the significant impact of 2-D envelope hygrothermal transfers on the indoor thermal and moisture behavior of building as well as on the energy building assessment. These conclusions are shown for different studied climates.

  6. Actual measurement, hygrothermal response experiment and growth prediction analysis of microbial contamination of central air conditioning system in Dalian, China.

    Science.gov (United States)

    Lv, Yang; Hu, Guangyao; Wang, Chunyang; Yuan, Wenjie; Wei, Shanshan; Gao, Jiaoqi; Wang, Boyuan; Song, Fangchao

    2017-04-03

    The microbial contamination of central air conditioning system is one of the important factors that affect the indoor air quality. Actual measurement and analysis were carried out on microbial contamination in central air conditioning system at a venue in Dalian, China. Illumina miseq method was used and three fungal samples of two units were analysed by high throughput sequencing. Results showed that the predominant fungus in air conditioning unit A and B were Candida spp. and Cladosporium spp., and two fungus were further used in the hygrothermal response experiment. Based on the data of Cladosporium in hygrothermal response experiment, this paper used the logistic equation and the Gompertz equation to fit the growth predictive model of Cladosporium genera in different temperature and relative humidity conditions, and the square root model was fitted based on the two environmental factors. In addition, the models were carried on the analysis to verify the accuracy and feasibility of the established model equation.

  7. 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.

  8. 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.

  9. Concrete enclosure to shield a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Villagrana M, L. E.; Rivera P, E.; De Leon M, H. A.; Soto B, T. G.; Hernandez D, V. M.; Vega C, H. R., E-mail: emmanuelvillagrana@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. Postal 336, 98000 Zacatecas (Mexico)

    2012-10-15

    In the aim to design a shielding for a {sup 239}PuBe isotopic neutron source several Monte Carlo calculations were carried out using MCNP5 code. First, a point-like source was modeled in vacuum and the neutron spectrum and the ambient dose equivalent were calculated at several distances ranging from 5 up to 150 cm, these calculations were repeated including air, and a 1 x 1 x 1 m{sup 3} enclosure that was shielded with 5, 15, 20, 25, 30, 50 and 80 cm-thick Portland type concrete walls. At all the points located inside the enclosure neutron spectra from 10{sup -8} up 0.5 MeV were the same regardless the distance from the source showing the room-return effect, for energies larger than 0.5 MeV neutron spectra are diminished as the distance increases. Outside the enclosure it was noticed that neutron spectra becomes -softer- as the concrete thickness increases due to reduction of mean neutron energy. With the ambient dose values the attenuation curve in terms of concrete thickness was calculated. (Author)

  10. Moisture supply in Danish single-family houses – the influence of building style

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Møller, Eva B.

    2017-01-01

    According to ISO 13788 internal moisture supply in dwellings can be described by humidity classes defined by outdoor temperature, occupancy and ventilation. Hygrothermal measurements in 500 Danish single-family houses were made to investigate if building style and geographical location are import......According to ISO 13788 internal moisture supply in dwellings can be described by humidity classes defined by outdoor temperature, occupancy and ventilation. Hygrothermal measurements in 500 Danish single-family houses were made to investigate if building style and geographical location...... are important as well. Further it was investigated whether snapshot measurements in materials could replace logging of relative humidity and temperature. Building type has only a limited effect on the moisture supply. Geographical location has an effect; however variations are not systematic. It is not possible...

  11. Optimal External-Memory Planar Point Enclosure

    DEFF Research Database (Denmark)

    Arge, Lars; Samoladas, Vasilis; Yi, Ke

    2007-01-01

    In this paper we study the external memory planar point enclosure problem: Given N axis-parallel rectangles in the plane, construct a data structure on disk (an index) such that all K rectangles containing a query point can be reported I/O-efficiently. This problem has important applications in e...... term O(K/B) is desired. To show this we prove a general lower bound on the tradeoff between the size of the data structure and its query cost. We also develop a family of structures with matching space and query bounds....

  12. 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.

  13. External Thermal Insulation Composite Systems: Critical Parameters for Surface Hygrothermal Behaviour

    Directory of Open Access Journals (Sweden)

    Eva Barreira

    2014-01-01

    Full Text Available External Thermal Insulation Composite Systems (ETICS are often used in Europe. Despite its thermal advantages, low cost, and ease of application, this system has serious problems of biological growth causing the cladding defacement. Recent studies pointed that biological growth is due to high values of surface moisture content, which mostly results from the combined effect of exterior surface condensation, wind-driven rain, and drying process. Based on numerical simulation, this paper points the most critical parameters involved in hygrothermal behaviour of ETICS, considering the influence of thermal and hygric properties of the external rendering, the effect of the characteristics of the façade, and the consequences of the exterior and interior climate on exterior surface condensation, wind-driven rain, and drying process. The model used was previously validated by comparison with the results of an “in situ” campaign. The results of the sensitivity analyses show that relative humidity and temperature of the exterior air, atmospheric radiation, and emissivity of the exterior rendering are the parameters that most influence exterior surface condensation. Wind-driven rain depends mostly on horizontal rain, building’s height, wind velocity, and orientation. The drying capacity is influenced by short-wave absorbance, incident solar radiation, and orientation.

  14. Effect of Hygrothermal Aging on the Mechanical Properties of Fluorinated and Nonfluorinated Clay-Epoxy Nanocomposites

    Science.gov (United States)

    Hamim, Salah U.; Singh, Raman P.

    2014-01-01

    Hydrophilic nature of epoxy polymers can lead to both reversible and irreversible/permanent changes in epoxy upon moisture absorption. The permanent changes leading to the degradation of mechanical properties due to combined effect of moisture and elevated temperature on EPON 862, Nanomer I.28E, and Somasif MAE clay-epoxy nanocomposites are investigated in this study. The extent of permanent degradation on fracture and flexural properties due to the hygrothermal aging is determined by drying the epoxy and their clay-epoxy nanocomposites after moisture absorption. Significant permanent damage is observed for fracture toughness and flexural modulus, while the extent of permanent damage is less significant for flexural strength. It is also observed that permanent degradation in Somasif MAE clay-epoxy nanocomposites is higher compared to Nanomer I.28E clay-epoxy nanocomposites. Fourier transform infrared (FTIR) spectroscopy revealed that both clays retained their original chemical structure after the absorption-desorption cycle without undergoing significant changes. Scanning electron microscopy (SEM) images of the fracture surfaces provide evidence that Somasif MAE clay particles offered very little resistance to crack propagation in case of redried specimens when compared to Nanomer I.28E counterpart. The reason for the observed higher extent of permanent degradation in Somasif MAE clay-epoxy system has been attributed to the weakening of the filler-matrix interface. PMID:27379285

  15. 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

    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...

  16. Enclosures Abound: Black Cultural Autonomy, Prison Regime and Public Education

    Science.gov (United States)

    Schnyder, Damien

    2010-01-01

    Since slavery, attempted enclosures upon Black spaces of cultural production and autonomy (i.e. music, language, art) have manifested in various forms. In the context of the post-industrial terrain of urban southern California, the formation of the prison is the dominant model of forced enclosure in the lives of Black people. Moving beyond the…

  17. 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

    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...

  18. On the Applicability of the Surface Equivalence Theorem Inside Enclosures

    DEFF Research Database (Denmark)

    Franek, Ondrej; Sørensen, Morten; Ebert, Hans

    2012-01-01

    A scenario of a generic printed circuit board (PCB) representing an electronic module inside a metallic enclosure is studied numerically. Following the surface equivalence theorem, the PCB is replaced with surface currents running on a Huygens box (HB) inside the enclosure and near-field errors...

  19. Humidity Buildup in Electronic Enclosures Exposed to Constant Conditions

    DEFF Research Database (Denmark)

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

    2017-01-01

    parameters such as openings in the enclosure (drain holes, intentional openings or leak) and sealing and casing material. Related corrosion reliability issues due to humidity buildup have been evaluated using an interdigitated surface insulation resistance pattern placed inside the enclosure during exposure...

  20. 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...

  1. Husbandry and enclosure influences on penguin behavior and conservation breeding.

    Science.gov (United States)

    Marshall, Andrew R; Deere, Nicolas J; Little, Holly A; Snipp, Ross; Goulder, Jackie; Mayer-Clarke, Stacey

    2016-09-01

    Multi-zoo comparisons of animal welfare are rare, and yet vital for ensuring continued improvement of zoo enclosures and husbandry. Methods are not standardized for the development of zoo enclosures based on multiple indicators, and case study species are required. This study compares behavior and breeding success to various enclosure and husbandry parameters for the Humboldt penguin, Spheniscus humboldti, for the development of improved enclosure design. Behavioral sampling was completed at Flamingo Land over a period of 8 months. Further data on behavior, enclosure design, and breeding success were collected via questionnaires, visits to zoos, and literature review. Breeding success was primarily influenced by colony age and number of breeding pairs, suggesting an important social influence on reproduction. Across zoos, there was also significant variation in behavior. The proportion of time spent in water varied between zoos (2-23%) and was used as an indicator of physical activity and natural behavior. Regression models revealed that water-use was best predicted by total enclosure area per penguin, followed by land area, with some evidence for positive influence of pool surface area per penguin. Predominantly linear/curvilinear increases in our biological indicators with enclosure parameters suggest that optimal conditions for S. humboldti were not met among the selected zoos. We propose revised minimum conditions for S. humboldti enclosure design, which exceed those in the existing husbandry guidelines. We present a framework for the evaluation of zoo enclosures and suggest that a rigorous scientific protocol be established for the design of new enclosures, based on multivariate methods. Zoo Biol. 35:385-397, 2016. © Wiley Periodicals, Inc.

  2. Initial computational fluid dynamics modeling of the Giant Magellan Telescope site and enclosure

    Science.gov (United States)

    Danks, Ryan; Smeaton, William; Bigelow, Bruce; Burgett, William

    2016-08-01

    In the era of extremely large telescopes (ELTs), with telescope apertures growing in size and tighter image quality requirements, maintaining a controlled observation environment is critical. Image quality is directly influenced by thermal gradients, the level of turbulence in the incoming air flow and the wind forces acting on the telescope. Thus any ELT enclosure must be able to modulate the speed and direction of the incoming air and limit the inflow of disturbed ground-layer air. However, gaining an a priori understanding of the wind environment's impacts on a proposed telescope is complicated by the fact that telescopes are usually located in remote, mountainous areas, which often do not have high quality historic records of the wind conditions, and can be subjected to highly complex flow patterns that may not be well represented by the traditional analytic approaches used in typical building design. As part of the design process for the Giant Magellan Telescope at Cerro Las Campanas, Chile; the authors conducted a parametric design study using computational fluid dynamics which assessed how the telescope's position on the mesa, its ventilation configuration and the design of the enclosure and windscreens could be optimized to minimize the infiltration of ground-layer air. These simulations yielded an understanding of how the enclosure and the natural wind flows at the site could best work together to provide a consistent, well controlled observation environment. Future work will seek to quantify the aerothermal environment in terms of image quality.

  3. Dialectic Form Finding of Passive and Adaptive Shading Enclosures

    Directory of Open Access Journals (Sweden)

    Sigrid Adriaenssens

    2014-08-01

    Full Text Available Form finding describes the process of finding a stable equilibrium shape for a system under a specific set of loads, for a set of boundary conditions and starting from an arbitrary initial geometry. However, form finding does not traditionally involve performance constraints such as energy-related criteria. Dialectic form finding is an extension of the process integrating energy-related design aspects. In this paper, dialectic form finding is employed as an approach for designing high performance architectural systems, driven by solar radiation control and structural efficiency. Two applications of dialectic form found shading enclosure structures, a passive and an active one, are presented. The first application example is a site-specific outdoor shading structure. The structure is based on a louver system designed to provide protection from ultraviolet radiation over a pre-defined target only when required, promoting natural lighting and ventilation. The second application example is a shape-shifting modular façade system that adapts its opacity in response to environmental fluctuations. The system can thus improve the environmental performance of a building. Moreover, the system explores elastic deformations for shape changes, reducing actuation requirements. These examples highlight the potential of the dialectic form-finding strategy for the design of high performance architectural integrated structures.

  4. Moisture Dynamics in Building Envelopes

    DEFF Research Database (Denmark)

    Peuhkuri, Ruut Hannele

    2003-01-01

    The overall scope of this Thesis "Moisture dynamics in building envelopes" has been to characterise how the various porous insulation materials investigated performed hygrothermally under conditions similar to those in a typical building envelope. As a result of the changing temperature...... and moisture conditions in the exterior weather and indoor climate the materials dynamically absorb and release moisture. The complexity of the impact of these conditions on the resulting moisture transport and content of the materials has been studied in this Thesis with controlled laboratory tests. The first......, results, and analysis are presented (Chapters 5-7). The major findings are discussed (Chapter 8), before the final conclusion (Chapter 9). The Appendices include the material parameters used, some additional results and the description of the simulation models....

  5. Recovering and Mining Asteroids with a Gas-Sealed Enclosure

    Science.gov (United States)

    Jenniskens, P.; Damer, B.; Norkus, R.; Pilotz, S.; Grigsby, B.; Adams, C.; Blair, B. R.

    2015-01-01

    The internal structure of weakly consolidated rubble piles and primitive asteroids can be studied closer to home, and such asteroids can be mined, if it is possible to create a gas-sealed enclosure around the asteroid.

  6. 30 CFR 18.31 - Enclosures-joints and fastenings.

    Science.gov (United States)

    2010-07-01

    ... Volume Volume of empty enclosure Less than 45 cu. in. 45 to 124 cu. in. inclusive More than 124 cu. in... closed with a plug secured by weld or braze. Bolts shall be provided at all corners. 8 The...

  7. 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....... 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....

  8. Experimental validation of coupled heat, air and moisture transfer modeling in multilayer building components

    Science.gov (United States)

    Ferroukhi, M. Y.; Abahri, K.; Belarbi, R.; Limam, K.; Nouviaire, A.

    2016-10-01

    The present paper lies to study the coupled heat, air and moisture transfer in multi-layer building materials. Concerning the modeling part, the interest is to predict the hygrothermal behavior, by developing a macroscopic model that incorporates simultaneously the diffusive, convective and conductive effects on the building elements. Heat transfer is considered in the strongly coupled situation where the mass and heat flux are temperature, vapor pressure and total pressure dependents. The model input parameters are evaluated experimentally through the development of various experimental prototypes in the laboratory. Thereafter, an experimental setup has been established in order to evaluate the hygrothermal process of several multilayer walls configurations. The experimental procedure consists to follow the temperature and relative humidity evolutions within the samples thickness, submitted to controlled and fixed boundary conditions. This procedure points out diverging conclusion between different testing materials combinations (e.g. red-brick and polystyrene). In fact, the hygrothermal behavior of the tested configurations is completely dependent on both materials selection and their thermophysical properties. Finally, comparison between numerical and experimental results showed good agreement with acceptable errors margins with an average of 3 %.

  9. Summary of the Effects of Two Years of Hygro-Thermal Cycling on a Carbon/Epoxy Composite Material

    Science.gov (United States)

    Kohlman, Lee W.; Binienda, Wieslaw K.; Roberts, Gary D.; Miller, Sandi G.; Pereira, J. Michael; Bail, Justin L.

    2011-01-01

    Composite materials are beginning to be used for structures in the fan section of commercial gas turbine engines. This paper explores the type of damage that could occur within one type of composite material after exposure to hygrothermal cycles (temperature/humidity cycles) that are representative of the environment in the fan section of an engine. The effect of this damage on composite material properties is measured. Chemical changes in the matrix material were limited to the exposed surface. Microcrack formation was identified in the composite material. This damage did not cause a significant reduction in tensile strength or impact penetration resistance of the composite material. Additional data is needed to assess the effect of damage on compressive strength.

  10. Effects of Fiber Reinforcement Architecture on the Hygrothermal-Mechanical Performance of Polyimide Matrix Composites for Aeropropulsion Applications

    Science.gov (United States)

    Shin, E. Eugene; Thesken, John C.; Sutter, James K.; Chuang, Kathy; Juhas, John; Veverka, Adrienne; Inghram, Linda; Papadopoulos, Demetrios; Burke, Chris; Scheiman, Dan

    2003-01-01

    A lightweight sandwich support structure, for the combustor chamber of a new generation liquid propellant rocket engine, was designed and fabricated using a polymer matrix composite (PMC) facesheet on a Ti honeycomb core. The PMC facesheet consisted of high stiffness carbon fiber, M40JB, and high temperature Polyimides, such as PMR-II-50 and HFPE-II-52. Six different fiber architectures; four harness satin (4HS) woven fabric, uni-tape, woven-uni hybrid, stitched woven fabric, stitched uni-tape and triaxial braided structures have been investigated for optimum stiffness-thickness-weight-hygrothermal performance design criteria for the hygrothermal-mechanical propulsion service exposure conditions including rapid heating up to 200 F/sec, maximum operating temperature of 600 F, internal pressure up to 100 psi. One of the specific objectives in this study is to improve composite blistering resistance in z-direction at minimum expense of in-plane mechanical properties. An extensive property-performance database including dry-wet mechanical properties at various temperatures, thermal-physical properties, such as blistering onset condition was generated for fiber architecture down-selection and design guidelines. Various optimized process methods such as vacuum bag compression molding, solvent assistant resin transfer molding (SaRTM), resin film infusion (RFI) and autoclaving were utilized for PMC panel fabrication depending on the architecture type. In the case of stitched woven fabric architecture, the stitch pattern in terms of stitch density and yarn size was optimized based on both in-plane mechanical properties and blistering performance. Potential reduction of the in-plane properties transverse to the line of stitching was also evaluated. Efforts have been made to correlate the experimental results with theoretical micro-mechanics predictions. Changes in deformation mechanism and failure sequences in terms of fiber architecture will be discussed.

  11. Numerical simulation of transient moisture and temperature distribution in polycarbonate and aluminum electronic enclosures

    DEFF Research Database (Denmark)

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

    2016-01-01

    ) analysis has been proven as a useful tool to exploit the detailed and visualized information about the fluid flows; and hence it can be helpful for predicting local climate inside the electronic enclosures. In this study, the temperature and moisture distributions inside an idealized electronic enclosure...... with some heat producing components are investigated. It is shown how the enclosure material can influence local climate inside the enclosure using transient numerical simulations. The effect of heat transfer coefficient and wall thickness of the enclosure is also investigated. The enclosure material...

  12. 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.

  13. Sound equalization in a large region of a rectangular enclosure

    DEFF Research Database (Denmark)

    Sarris, John C.; Jacobsen, Finn; Cambourakis, Georg E.

    2004-01-01

    The work presented by Santillán [J. Acoust. Soc. Am. 110, 1989–1997 (2001)] about equalization at low frequencies in rectangular enclosures is extended, and topics that remained unaddressed in the original study are treated in this paper. A modification is introduced to the original cost function...... the dependence of the limits of the zone of equalization on factors such as the damping constant of the modes of the enclosure, the number of sources, and the driving frequency. ©2004 Acoustical Society of America.......The work presented by Santillán [J. Acoust. Soc. Am. 110, 1989–1997 (2001)] about equalization at low frequencies in rectangular enclosures is extended, and topics that remained unaddressed in the original study are treated in this paper. A modification is introduced to the original cost function...

  14. 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...

  15. Free Convection and Irreversibility Analysis inside a Circular Porous Enclosure

    Directory of Open Access Journals (Sweden)

    Shohel Mahmud

    2003-12-01

    Full Text Available We investigate the nature of heat transfer and entropy generation for natural convection in a two-dimensional circular section enclosure. The enclosure is assumed to fill with porous media. The Darcy momentum equation is used to model the porous media. The full governing differential equations are simplified with the Boussinesq approximation and solved by a finite volume method. Whereas the Prandtl number Pr is fixed to 1.0. Results are presented in terms of Nusselt number, entropy generation number, and Bejan number.

  16. Can crawl space temperature and moisture conditions be calculated with a whole-building hygrothermal simulation tool?

    DEFF Research Database (Denmark)

    Vanhoutteghem, Lies; Morelli, Martin; Sørensen, Lars Schiøtt

    2017-01-01

    Temperature and moisture measurements were made in a ventilated attic on a house with 200 mm mineral wool insulation. The measurements showed that 1) solar radiation had a great effect on the temperature in the attic; 2) moisture content reached a level below the risk of mold formation – no mold...... was constructed with a moisture barrier....

  17. A drying coefficient for building materials

    DEFF Research Database (Denmark)

    Scheffler, Gregor Albrecht; Plagge, Rudolf

    2009-01-01

    The drying experiment is an important element of the hygrothermal characterisation of building materials. Contrary to other moisture transport experiments as the vapour diffusion and the water absorption test, it is until now not possible to derive a simple coefficient for the drying. However...... coefficient is defined which can be determined based on measured drying data. The correlation of this coefficient with the water absorption and the vapour diffusion coefficient is analyzed and its additional information content is critically challenged. As result, a drying coefficient has been derived...... and defined as a new and independent material parameter. It contains information about the moisture transport properties throughout the wide range of moisture contents from hygroscopic up to saturation. With this new and valuable coefficient, it is now possible to distinguish and select building materials...

  18. 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...

  19. Analysis of the building constructions from the point of view of possible freeze-thaw deterioration

    Science.gov (United States)

    Maděra, Jiří; Černý, Robert

    2016-07-01

    A mathematical model for the calculation of the amount of frozen water in the porous building materials is presented in this paper. The model is based on the analysis of temperature and moisture content fields in the investigated material together with its pore size distribution function and is primarily designed for the relative assessment of building constructions. The newly formulated model is applied on several wall assemblies made of traditional structural materials and their hygrothermal performance is analyzed in terms of possible frost induced damage. Based on the model outputs some future objectives are drawn.

  20. 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...

  1. Wind fence enclosures for infrasonic wind noise reduction.

    Science.gov (United States)

    Abbott, JohnPaul; Raspet, Richard; Webster, Jeremy

    2015-03-01

    A large porous wind fence enclosure has been built and tested to optimize wind noise reduction at infrasonic frequencies between 0.01 and 10 Hz to develop a technology that is simple and cost effective and improves upon the limitations of spatial filter arrays for detecting nuclear explosions, wind turbine infrasound, and other sources of infrasound. Wind noise is reduced by minimizing the sum of the wind noise generated by the turbulence and velocity gradients inside the fence and by the area-averaging the decorrelated pressure fluctuations generated at the surface of the fence. The effects of varying the enclosure porosity, top condition, bottom gap, height, and diameter and adding a secondary windscreen were investigated. The wind fence enclosure achieved best reductions when the surface porosity was between 40% and 55% and was supplemented by a secondary windscreen. The most effective wind fence enclosure tested in this study achieved wind noise reductions of 20-27 dB over the 2-4 Hz frequency band, a minimum of 5 dB noise reduction for frequencies from 0.1 to 20 Hz, constant 3-6 dB noise reduction for frequencies with turbulence wavelengths larger than the fence, and sufficient wind noise reduction at high wind speeds (3-6 m/s) to detect microbaroms.

  2. Fogging formulations for fixation of particulate contamination in ductwork and enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Maresca, Jr., Joseph W.; Kostelnik, Lori M.; Kriskivich, James R.; Demmer, Rick L.; Tripp, Julia L.

    2015-09-08

    A method and an apparatus using aqueous fixatives for fogging of ventilation ductwork, enclosures, or buildings containing dust, lint, and particulates that may be contaminated by radionuclides and other dangerous or unsafe particulate contaminants, which method and apparatus are capable of (1) obtaining full coverage within the ductwork and (2) penetrating and fixing the lint, dust and large particles present in the ductwork so that no airborne particles are released during or after the application of the fixative. New aqueous fogging solutions outperform conventional glycerin-based solutions. These aqueous solutions will fog using conventional methods of application and contain a surfactant to aid wetting and penetration of the lint and dust, a binder to stabilize loose or respirable particles, and an agent to aid in fogging and enhance adhesiveness. The solutions are safe and easy to use.

  3. The use of branch enclosures to assess direct and indirect effects of elevated CO{sub 2} on photosynthesis, respiration and isoprene emission of Populus alba leaves

    Energy Technology Data Exchange (ETDEWEB)

    Brilli, F.; Tricoli, D.; Fares, S.; Loreto, F. [CNR - Istituto di Biologia Agroambientale e Forestale, Roma (Italy); Centritto, M. [CNR - Istituto sull' Inquinamento Atmosferico, Roma (Italy)

    2008-09-30

    Forests emit a wide range of volatile organic compounds (VOCs), mainly isoprenoids. Isoprenoids may provide enhanced leaf thermotolerance, and/or may scavenge ozone and help provide protection against oxidative stress, but none of these hypotheses have been proved beyond reasonable doubt. Some isoprenoids are also active molecules in plant defense against biotic stresses, deterring herbivores from feeding and protecting wounded parts of the plants from invasion by bacteria and fungi. Biogenic VOC emission rates can also have direct and indirect effects on the carbon cycle at terrestrial level. A direct effect occurs because a part of the carbon assimilated by plants through photosynthesis is immediately re-emitted in the atmosphere as biogenic VOCs. In general about 1-2% of the carbon fixed by photosynthesis is released as isoprene by leaves, and this percentage can increase dramatically in stressed plants. The indirect effect of biogenic VOCs on the carbon cycle is linked to the high reactivity of these coupounds with anthropogenic and natural compounds (mainly NO{sub x}) leading to high ozone episodes and photochemical smog, particularly during periods of high radiation and temperature, when biogenic VOC emissions are usually high. This in turn causes the accumulation of slowly reacting compounds, such as methane (CH{sub 4}) and carbon dioxide (CO{sub 2}), thus indirectly potentially contributing to the global warming associated with the build-up of greenhouse gases in the atmosphere. In the context of global cliamte change, there is therefore considerable interest in understanding how isoprenoids emission may change in the future, especially in response to CO{sub 2} concentration increase. The authors used a novel system of branch enclosures to study the impact of elevated CO{sub 2} (900 ppm) on the gas-exchange characteristics of developed and developing leaves of white poplar (Populus alba L.), as well as of leaves subsequently developing at ambient CO{sub 2

  4. Characteristics of Electromagnetic Coupling with A Wire through Shielding Enclosure

    Directory of Open Access Journals (Sweden)

    Yanpeng Sun

    2013-09-01

    Full Text Available The paper presents a numerical method based on Finite Difference Time Domain (FDTD in both frequency and time domain for modeling the coupling of an incident electromagnetic pulse(EMP with a conducting wire through a metallic shielding enclosure with a small aperture. Simulation and analysis are done by radius, length, and number of the wires, the incidence angle of EMP and the polaration angle of electric field in consideration. The simulation result shows that interference of the electromagnetic coupling into the shielding enclosure can be affected in different degrees by above factors. At low frequency, the larger the leakage length, the radius or the number of the wire penetrated into the cavity, the more interference is coupled into the shielding cavity from electromagnetic field. Also, the smaller the incident direction angle of propagation of the electromagnetic pulse or the polarization direction angle of the incident electric field, the more easily the electromagnetic interference is coupled into the cavity.

  5. 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.

  6. Radiative transfer in rectangular enclosures - A discretized exchange factor solution

    Science.gov (United States)

    Naraghi, M. H. N.; Kassemi, M.

    1988-01-01

    The discretized exchange factor method is used to analyze radiative exchange in a rectangular enclosure. The results compare excellently with those of other methods, especially the zonal method. Since the direct exchange factors are between nodal points no integration is necessary for evaluation of these factors. It is found that the present approach provides accurate results even when a small number of nodes is used.

  7. Acoustic control in enclosures using optimally designed Helmholtz resonators

    Science.gov (United States)

    Driesch, Patricia Lynne

    A virtual design methodology is developed to minimize the noise in enclosures with optimally designed, passive, acoustic absorbers (Helmholtz resonators). A series expansion of eigen functions is used to represent the acoustic absorbers as external volume velocities, eliminating the need for a solution of large matrix eigen value problems. A determination of this type (efficient model/reevaluation approach) significantly increases the design possibilities when optimization techniques are implemented. As a benchmarking exercise, this novel methodology was experimentally validated for a narrowband acoustic assessment of two optimally designed Helmholtz resonators coupled to a 2D enclosure. The resonators were tuned to the two lowest resonance frequencies of a 30.5 by 40.6 by 2.5 cm (12 x 16 x 1 inch) cavity with the resonator volume occupying only 2% of the enclosure volume. A maximum potential energy reduction of 12.4 dB was obtained at the second resonance of the cavity. As a full-scale demonstration of the efficacy of the proposed design method, the acoustic response from 90--190 Hz of a John Deere 7000 Ten series tractor cabin was investigated. The lowest cabin mode, referred to as a "boom" mode, proposes a significant challenge to a noise control engineer since its anti-node is located near the head of the operator and often generates unacceptable sound pressure levels. Exploiting the low frequency capability of Helmholtz resonators, lumped parameter models of these resonators were coupled to the enclosure via an experimentally determined acoustic model of the tractor cabin. The virtual design methodology uses gradient optimization techniques as a post processor for the modeling and analysis of the unmodified acoustic interior to determine optimal resonator characteristics. Using two optimally designed Helmholtz resonators; potential energy was experimentally reduced by 3.4 and 10.3 dB at 117 and 167 Hz, respectively.

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

    Directory of Open Access Journals (Sweden)

    K. Flydal

    2009-01-01

    Full Text Available 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 50×400 m enclosures; two treatment enclosures with power lines and two control enclosures. Reindeer from two herds, one from Kautokeino (domestic tame and one from Vågå, (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.

  9. 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.

  10. Assessing the benefits of design for recycling for plastics inelectronics: A case study of computer enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Masanet, Eric; Horvath, Arpad

    2007-12-31

    With the emergence of extended producer responsibilityregulations for electronic devices, it is becoming increasingly importantfor electronics manufacturers to apply design for recycling (DFR) methodsin the design of plastic enclosures. This paper presents an analyticalframework for quantifying the environmental and economic benefits of DFRfor plastic computer enclosures during the design process, usingstraightforward metrics that can be aligned with corporate environmentaland financial performance goals. The analytical framework is demonstratedvia a case study of a generic desktop computer enclosure design, which isrecycled using a typical US "take-back" system for plastics from wasteelectronics. The case study illustrates how the analytical framework canbe used by the enclosure designer to quantify the environmental andeconomic benefits of two important DFR strategies: choosing high-valueresins and minimizing enclosure disassembly time. Uncertainty analysis isperformed to quantify the uncertainty surrounding economic conditions inthe future when the enclosure is ultimately recycled.

  11. Research on Mutual Influence between the Enclosure Structures and the Heat Exchange Pipes in Enclosure Structures%围护结构内的热交换管和结构的相互影响研究

    Institute of Scientific and Technical Information of China (English)

    夏才初; 朱建龙; 曹诗定

    2012-01-01

    地源热泵系统是对地温能进行利用的一种新型技术,其中在地下连续墙或钻孔灌注桩内埋设热交换管称为墙埋管和桩埋管.但是在地下连续墙或灌注桩中埋管是否会对其承载能力造成影响,以及地下连续墙或灌注桩的变形是否会对埋管产生影响分别是结构和暖通两个专业关心的问题.通过地下连续墙和灌注桩埋管前后的截面面积和惯性矩的变化,分析了埋管对其承载能力的影响.根据围护结构的结构特点以及允许位移,分析了围护结构的变形对埋管的影响.同时还研究了在地源热泵运营时,防冻液渗入混凝土可能引起的对围护结构的影响及其避免措施,研究结果表明,围护结构内埋管对其承载能力的影响相当小,围护结构的变形也不会影响热交换管的正常使用.%As a new kind of building energy saving technology which makes use of geothermal energy, the ground-source heat pump comprises the heat exchange pipes buried in the diaphragm walls or in cast-in-situ bored piles which are called energy walls and energy piles respectively. But both the heating and ventilating discipline and the structure discipline are caring for two aspects: whether the pipes will influence the bearing capacity of the enclosure structure and whether the deformations of the enclosure structure will influence the buried pipes. The bearing capacity influenced by the buried pipes is analyzed through the variation of the moment of inertia and the area of the diaphragm wall and the bored pile. The buried pipes influenced by the enclosure structure are studied according to the characteristics of the enclosure structures and the allowable displacements. It is also discussed that the antifreezing fluid penetrating the concrete will have an effect on the enclosure structure when the heat pump system is in operation, and the solutions to the prevention measures are presented. The results show that the buried pipes

  12. Efficient ventilation in school buildings. Design guidebook; Ventilation performante dans les ecoles. Guide de conception

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This guidebook aims at giving practical advices for the design of ventilation systems for school buildings in order to maintain air quality levels and energy consumptions conformable with the real needs: 1 - the specific problem of schools (various types of rooms, particular indoor pollutions); 2 - main criteria to consider (air quality and hygiene, hygro-thermal comfort, ventilation efficiency, acoustic comfort, energy mastery); 3 - main existing solutions (simple-flux blow-off or blow-in mechanical ventilation systems, dual-flux systems, air conditioning systems); 4 - choice of an adapted solution (selection criteria, global solution for the school); setting-up and follow-up (rules, training, maintenance). (J.S.)

  13. Questing ixodid ticks on the vegetation of sable antelope and multi-herbivore enclosures in Thabazimbi

    Directory of Open Access Journals (Sweden)

    André C. Uys

    2015-03-01

    Full Text Available This survey of ixodid ticks was the first to compare the species composition and population dynamics of free-living ticks in intensive, sable antelope breeding enclosures, now commonplace in commercial wildlife ranching in South Africa, with those of multi-herbivore enclosures. The species composition, abundance and seasonal abundance of questing ixodid ticks on the vegetation in intensive breeding enclosures for sable antelope (Hippotragus niger, on which strategic tick control is practised, were compared with those of ticks in a multi-species herbivore enclosure surrounding the breeding enclosures in which no tick control is practised. A total of eight ixodid tick species were collected by drag-sampling the woodland and grassland habitats in each enclosure type monthly from July 2011 to July 2013. Rhipicephalus decoloratus, a potential vector of fatal tick-borne disease in sable antelopes, was the most abundant, accounting for 65.4% of the total number of ticks collected in the sable enclosures, whilst representing only 25.4% of number of ticks collected in the multi-species herbivore enclosure. Rhipicephalus decoloratus and R. evertsi evertsi were more abundant than R. appendiculatus (both p < 0.05 and Amblyomma hebraeum (p < 0.001 and p < 0.01, respectively. Rhipicephalus decoloratus larvae were collected throughout the year, with peak collections in November 2012 and October to December 2013 in the sable enclosures; and in April/May 2012 and February/April 2013 in the multi-species herbivore enclosure. More R. decoloratus were recovered in the second year than in the first year in the grassland habitat of the sable enclosures (V = 7.0, p < 0.05 possibly as a result of acaricide resistance. The apparent temporal over-abundance of R. decoloratus in sable antelope breeding enclosures, in the face of strategic tick control, is of concern and requires further investigation.

  14. A survey of enclosure suspension and rotation systems for 3-15m telescopes

    Science.gov (United States)

    Bigelow, Bruce C.; Loewen, Nathan P.; van Vuuren, Emile; Burgett, William S.

    2016-07-01

    The suspension and rotation systems (typically called bogies) for Extremely Large Telescope (ELT) enclosures will carry structures that are 2-3 times greater in diameter and much heavier than enclosures for the previous generation of 6-10m telescopes. Via on-site visits and/or engineering documentation, we have surveyed eleven optical, infrared, and submillimeter 3-15m telescope enclosures, and report on key design features of the suspension and rotation systems, including wheel and track geometry, the wheel/track interface, average load per wheel, rotation drive method, etc. We discuss key considerations for the development of future suspension and rotation systems for ELT enclosures.

  15. Development of a General Method for Determining Leak Rates from Limiting Enclosures

    Science.gov (United States)

    Zografos, A. I.; Blackwell, C. C.; Harper, Lynn D. (Technical Monitor)

    1994-01-01

    This paper discusses the development of a general method for the determination of very low leak rates from limiting enclosures. There are many methods that can be used to detect and repair leaks from enclosures. Many methods have also been proposed that allow the estimation of actual leak rates, usually expressed as enclosure volume turnover. The proposed method combines measurements of the state variables (pressure, temperature, and volume) as well as the change in the concentration of a tracer gas to estimate the leak rate. The method was applied to the containment enclosure of the Engineering Development Unit of the CELSS Test Facility, currently undergoing testing at the NASA Ames Research Center.

  16. Five design options for permanent total enclosures (PTEs)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This paper discusses how companies in the printing industry are looking more to the use of permanent total enclosures (PTEs) as a means to demonstrate compliance with new Clean Air Act standards for hazardous air pollutants. The advantages of this method is that by following design guidelines and meeting the EPA five point criteria for a fully enclosed room, then one may assume 100% capture of contaminants. This factor often raises the advantages of this method over other control methods which put the responsibility upon the user to demonstrate compliance with required control levels.

  17. Short-Pulsed Wavepacket Propagation in Ray-Chaotic Enclosures

    CERN Document Server

    Castaldi, Giuseppe; Pinto, Innocenzo M

    2011-01-01

    Wave propagation in ray-chaotic scenarios, characterized by exponential sensitivity to ray-launching conditions, is a topic of significant interest, with deep phenomenological implications and important applications, ranging from optical components and devices to time-reversal focusing/sensing schemes. Against a background of available results that are largely focused on the time-harmonic regime, we deal here with short-pulsed wavepacket propagation in a ray-chaotic enclosure. For this regime, we propose a rigorous analytical framework based on a short-pulsed random-plane-wave statistical representation, and check its predictions against the results from finite-difference-time-domain numerical simulations.

  18. Natural convection in polygonal enclosures with inner circular cylinder

    Directory of Open Access Journals (Sweden)

    Habibis Saleh

    2015-12-01

    Full Text Available This study investigates the natural convection induced by a temperature difference between cold outer polygonal enclosure and hot inner circular cylinder. The governing equations are solved numerically using built-in finite element method of COMSOL. The governing parameters considered are the number of polygonal sides, aspect ratio, radiation parameter, and Rayleigh number. We found that the number of contra-rotative cells depended on polygonal shapes. The convection heat transfer becomes constant at L / D > 0 . 77 and the polygonal shapes are no longer sensitive to the Nusselt number profile.

  19. 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...... to predict humidity-related reliability of a printed circuit board (PCB) located in a cabinet by combining structural reliability methods and non-linear diffusion models. This framework can, thus, be used for reliability prediction from a climatic point-of-view. The proposed numerical approach is then tested...

  20. Managment and construction of the Large Binocular Telescope enclosure: Meeting unusual challenges with a competitive discipline

    Science.gov (United States)

    Slagle, James H.; Hill, John M.; Davison, Warren B.; Hart, Wood; Teran, Jose U.

    1998-08-01

    Planning, estimating, and building a telescope and its enclosure within a budget is a challenge to any project staff. The Large Binocular Telescope (LBT) project office goal has been to break every phase of the project into small packages and competitively bid the packages. In this way the project office can minimize costs and keep the project budget from escalating out of control. This paper will discuss both the unique and common problems associated with the building of telescopes into the next millennium. The discussion is centered on the planning and execution phases of construction for the LBT, located on Mt. Graham in Arizona. The paper will discuss the effects of delays on the actual start of the telescope due to environmental issues and the impact the delays had on design and budget. The paper will provide the solutions that have been incorporated by the LBT project office to maximize the quality of construction while holding costs to a minimum. The use of a team approach by the contractors, engineers, and the project office has been successful in maintaining quality construction at a reasonable cost.

  1. Suitable scheme study of Chinese Building Energy Efficiency CDM Projects

    Science.gov (United States)

    Huang, Beijia; Yang, Haizhen; Wang, Shaoping; Wang, Feng

    2010-11-01

    China has great potential to develop Building Energy Efficiency Clean Development Mechanism (BEE CDM) projects, although have many challenges. Our results show that large-scale public buildings and urban residential buildings have relatively high BEE CDM potential, when comparing their characteristics to the CDM project requirements. The building enclosure, illumination energy conservation, air condition energy saving, solar thermal, and solar photovoltaic technology have relatively high application potential while considering the energy saving potential and marginal emission reduction cost. Case study of large-scale buildings shows that technology integration of building enclosure, illumination energy conservation, air condition energy saving, solar thermal can reduce required building number to 130 in order to meet the 1×105 tCO2 e/a reduction criteria. Some suggestions are also given in this paper.

  2. Application of data mining techniques in the analysis of indoor hygrothermal conditions

    CERN Document Server

    Ramos, Nuno M M; Almeida, Ricardo M S F; Simões, Maria L; Manuel, Sofia

    2016-01-01

    The main benefit of the book is that it explores available methodologies for both conducting in-situ measurements and adequately exploring the results, based on a case study that illustrates the benefits and difficulties of concurrent methodologies. The case study corresponds to a set of 25 social housing dwellings where an extensive in situ measurement campaign was conducted. The dwellings are located in the same quarter of a city. Measurements included indoor temperature and relative humidity, with continuous log in different rooms of each dwelling, blower-door tests and complete outdoor conditions provided by a nearby weather station. The book includes a variety of scientific and engineering disciplines, such as building physics, probability and statistics and civil engineering. It presents a synthesis of the current state of knowledge for benefit of professional engineers and scientists.

  3. Optimisation of mesh enclosures for nursery rearing of juvenile sea cucumbers.

    Science.gov (United States)

    Purcell, Steven W; Agudo, Natacha S

    2013-01-01

    Mariculture of tropical sea cucumbers is promising, but the nursery rearing of juveniles is a bottleneck for farming and sea ranching. We conducted four medium-scale experiments lasting 3-6 weeks, using thousands of cultured juvenile sandfish Holothuria scabra, to optimise nursery rearing in mesh enclosures in earthen seawater ponds and to test rearing in enclosures in the sea. In one experiment, survival in fine-mesh enclosures (1 m(3); 660-µm mesh) related nonlinearly to juvenile size, revealing a threshold body length of 5-8 mm for initial transfer from hatchery tanks. Survival in enclosures within ponds in the other experiments ranged from 78-97%, and differences in growth rates among experiments were explained largely by seasonal differences in seawater temperatures in ponds. Stripped shadecloth units within fine-mesh enclosures increased feeding surfaces and improved growth rates by >15%. On the other hand, shading over the enclosures may lower growth rates. Following the rearing in fine-mesh enclosures, small juveniles (0.5 to 1 g) were grown to stocking size (3-10 g) in coarse-mesh enclosures of 1-mm mesh. Sand or mud added to coarse-mesh enclosures did not significantly improve growth compared to controls without sediment. Survival of sandfish juveniles in coarse-mesh enclosures set on the benthos within seagrass beds differed between two sheltered bays and growth was slow compared to groups within the same type of enclosures in an earthen pond. Our findings should lead to significant improvement in the cost-effectiveness of rearing sandfish juveniles to a stocking size compared to established methods and highlight the need for further research into nursery systems in the sea.

  4. Numerical analysis of heat, air, and moisture transfers in a wooden building material

    Directory of Open Access Journals (Sweden)

    Mnasri Faiza

    2017-01-01

    Full Text Available The present paper aims to predict the hygrothermal behavior of massive wood panel considered as bio-based building material. In this context, we developed a macroscopic model coupled no linear heat, air, and moisture transfers that incorporates simultaneously the effect of thermal diffusion and infiltration phenomenon on the building material. The model inputs parameters were evaluated experimentally according to the recognized standards of material’s characterization. Therefore, numerous series of hygrothermal calculation were carried out on the 1-D and 2-D configuration in order to assess the dimensionless effect on such wooden material. Two types of boundary conditions were considered and examined. The first are at the material scale of wood drying process. The second type of conditions is at the wall scale, where the conditions of the building ambiance are considered. Moreover, the model sensitivity to the driving potentials coupling and to the parameters variability was considered and examined. It has been found that the coupling in the model had a remarkable impact on both kinetics of temperature and moisture content.

  5. ENCLOSURE EXPERIMENTS ON AND LACUSTRINE PRACTICE FOR ELIMINATING MICROCYSTIS BLOOM

    Institute of Scientific and Technical Information of China (English)

    刘建康; 谢平

    2002-01-01

    Microcystis bloom, one of the most objectionable characteristics of eutrophication in tropical and subtropical waters, occurred in Donghu Lake (East Lake) of Wuhan every summer from the 1970s up to 1984, but from 1985 up tonow failed to occur there. The cause of its disappearance remained in obscurityuntil recently. In situ enclosure experiments in the lake for three years showed that the stocking of the filter-feeding silver carp (Hypophthalmichthys molitrix) and big-head carp (Aristichthys nobilis) played a decisive role in eliminating Microcystis bloom from the lake; but that recurrence of the bloom is possibleunder certain conditions. This paper presents the details and the results of enclosure experiments. The authors' analysis of fish biomass data obtained by echo-sounding and the fishery production of the lake over the years, revealed that the recurrence of Microcystis bloom can be prevented so long as the combined biomass of silver carp and big-head carp remains at or exceeds 50 g per cubic meter of lakewater, as was the case in the lake's 1985 fish yield of 1015 t.``

  6. Mixed convection inside nanofluid filled rectangular enclosures with moving bottom wall

    Directory of Open Access Journals (Sweden)

    Mahmoodi Mostafa

    2011-01-01

    Full Text Available The mixed convection fluid flow and heat transfer in lid-driven rectangular enclosures filled with the Al2O3-water nanofluid is investigated numerically. The left and the right vertical walls as well as the top horizontal wall of the enclosure are maintained at a constant cold temperature Tc. The bottom horizontal wall of the enclosure, which moves from left to right, is kept at a constant hot temperature Th, with Th>Tc. The governing equations written in terms of the primitive variables are solved using the finite volume method and the SIMPLER algorithm. Using the developed code, a parametric study is performed and the effects of the Richardson number, the aspect ratio of the enclosure and the volume fraction of the nanoparticles on the fluid flow and heat transfer inside the enclosure are investigated. The results show that at low Richardson numbers, a primary counterclockwise vortex is formed inside the enclosure. More over it is found that for the range of the Richardson number considered, 10-1-101, the average Nusselt number of the hot wall, increases with increasing the volume fraction of the nanoparticles. Also it is observed that the average Nusselt number of the hot wall of tall enclosures is more that to that of the shallow enclosures.

  7. A simple formula for insertion loss prediction of large acoustical enclosures using statistical energy analysis method

    Directory of Open Access Journals (Sweden)

    Kim Hyun-Sil

    2014-12-01

    Full Text Available Insertion loss prediction of large acoustical enclosures using Statistical Energy Analysis (SEA method is presented. The SEA model consists of three elements: sound field inside the enclosure, vibration energy of the enclosure panel, and sound field outside the enclosure. It is assumed that the space surrounding the enclosure is sufficiently large so that there is no energy flow from the outside to the wall panel or to air cavity inside the enclosure. The comparison of the predicted insertion loss to the measured data for typical large acoustical enclosures shows good agreements. It is found that if the critical frequency of the wall panel falls above the frequency region of interest, insertion loss is dominated by the sound transmission loss of the wall panel and averaged sound absorption coefficient inside the enclosure. However, if the critical frequency of the wall panel falls into the frequency region of interest, acoustic power from the sound radiation by the wall panel must be added to the acoustic power from transmission through the panel.

  8. 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.

  9. Cascading trophic interactions in the littoral zone: an enclosure experiment in shallow Lake Stigsholm, Denmark

    DEFF Research Database (Denmark)

    Jeppesen, E.; Søndergaard, M.; Christoffersen, K.;

    2002-01-01

    polyethylene enclosures, which 2.5 month prior to the experiments were mounted above the water surface on a stainless steel ring to allow development of natural pelagic, benthic and epiphytic communities. Half of the enclosures were kept free of plants by harvesting. In late July, the sheets were released from...

  10. 32 CFR Enclosure 1 - Requirements for Environmental Considerations-Global Commons

    Science.gov (United States)

    2010-07-01

    ...-Global Commons 1 Enclosure 1 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE.... 187, Encl. 1 Enclosure 1—Requirements for Environmental Considerations—Global Commons A. General. This... actions that do significant harm to the environment of the global commons. The focus is not the place of...

  11. Prediction of deformation and hygro-thermal stresses distribution in PEM fuel cell vehicle using three-dimensional CFD model

    Energy Technology Data Exchange (ETDEWEB)

    Sadiq Al-Baghdadi, Maher A.R. [Fuel Cell Research Center, International Energy & Environment Foundation, Al-Najaf, P.O.Box 39 (Iraq)

    2012-07-01

    Durability is one of the most critical remaining issues impeding successful commercialization of broad PEM fuel cell transportation energy applications. Automotive fuel cells are likely to operate with neat hydrogen under load-following or load-levelled modes and be expected to withstand variations in environmental conditions, particularly in the context of temperature and atmospheric composition. In addition, they are also required to survive over the course of their expected operational lifetimes i.e., around 5,500 hrs, while undergoing as many as 30,000 startup/shutdown cycles. The damage mechanisms in a PEM fuel cell are accelerated by mechanical stresses arising during fuel cell assembly (bolt assembling), and the stresses arise during fuel cell running, because it consists of the materials with different thermal expansion and swelling coefficients. Therefore, in order to acquire a complete understanding of the damage mechanisms in the membrane, mechanical response under steady-state hygro-thermal stresses should be studied under real cell operating conditions and in real cell geometry (three-dimensional). In this work, full three-dimensional, non-isothermal computational fluid dynamics model of a PEM fuel cell has been developed to simulate the stresses inside the PEM fuel cell, which are occurring during fuel cell assembly (bolt assembling), and the stresses arise during fuel cell running due to the changes of temperature and relative humidity. A unique feature of the present model is to incorporate the effect of hygro and thermal stresses into actual three-dimensional fuel cell model. In addition, the temperature and humidity dependent material properties are utilize in the simulation for the membrane. The model is shown to be able to understand the many interacting, complex electrochemical, transport phenomena, and stresses distribution that have limited experimental data. This model is used to study and analyse the effect of operating parameters on the

  12. Prediction of deformation and hygro-thermal stresses distribution in PEM fuel cell vehicle using three-dimensional CFD model

    Directory of Open Access Journals (Sweden)

    Maher A.R. Sadiq Al-Baghdadi

    2012-01-01

    Full Text Available Durability is one of the most critical remaining issues impeding successful commercialization of broad PEM fuel cell transportation energy applications. Automotive fuel cells are likely to operate with neat hydrogen under load-following or load-levelled modes and be expected to withstand variations in environmental conditions, particularly in the context of temperature and atmospheric composition. In addition, they are also required to survive over the course of their expected operational lifetimes i.e., around 5,500 hrs, while undergoing as many as 30,000 startup/shutdown cycles. The damage mechanisms in a PEM fuel cell are accelerated by mechanical stresses arising during fuel cell assembly (bolt assembling, and the stresses arise during fuel cell running, because it consists of the materials with different thermal expansion and swelling coefficients. Therefore, in order to acquire a complete understanding of the damage mechanisms in the membrane, mechanical response under steady-state hygro-thermal stresses should be studied under real cell operating conditions and in real cell geometry (three-dimensional. In this work, full three-dimensional, non-isothermal computational fluid dynamics model of a PEM fuel cell has been developed to simulate the stresses inside the PEM fuel cell, which are occurring during fuel cell assembly (bolt assembling, and the stresses arise during fuel cell running due to the changes of temperature and relative humidity. A unique feature of the present model is to incorporate the effect of hygro and thermal stresses into actual three-dimensional fuel cell model. In addition, the temperature and humidity dependent material properties are utilize in the simulation for the membrane. The model is shown to be able to understand the many interacting, complex electrochemical, transport phenomena, and stresses distribution that have limited experimental data. This model is used to study and analyse the effect of operating

  13. An International Project on Indoor Air Quality Design and Control in Low Energy Residential Buildings

    DEFF Research Database (Denmark)

    Rode, Carsten; Abadie, Marc; Qin, Menghao

    2016-01-01

    comfortable and healthy indoor environments. New paradigms for demand control of ventilation will be investigated, which consider the pollution loads and occupancy in buildings. As well, the thermal and moisture conditions of such advanced building shall be considered because of interactions between...... focal points to limiting energy consumption for thermally conditioning the indoor environment will be to possibly reducing the ventilation rate, or making it in a new way demand controlled. However, this must be done such that it does not have adverse effects on indoor air quality (IAQ). Annex 68...... the hygrothermal parameters, the chemical conditions, ventilation and the wellbeing of occupants. The project is divided into the five subtasks: 1. Defining the metrics. 2. Pollutant loads in residential buildings. 3. Modeling. 4. Strategies for design and control of buildings. 5. Field measurements and case...

  14. Influence of Indoor Hygrothermal Conditions on Human Quality of Life in Social Housing

    Science.gov (United States)

    Soares, Sara; Fraga, Silvia; Delgado, Joao M.P.Q.

    2015-01-01

    adopt a similar approach. The case study results will allow to define building rehabilitation policies, improving residents’ quality of life and adding great contribution to public health promotion. PMID:26753162

  15. A CFD analysis on the effect of ambient conditions on the hygro-thermal stresses distribution in a planar ambient air-breathing PEM fuel cell

    Directory of Open Access Journals (Sweden)

    Maher A.R. Sadiq Al-Baghdadi

    2011-07-01

    Full Text Available The need for improved lifetime of air-breathing proton exchange membrane (PEM fuel cells for portable applications necessitates that the failure mechanisms be clearly understood and life prediction models be developed, so that new designs can be introduced to improve long-term performance. An operating air-breathing PEM fuel cell has varying local conditions of temperature and humidity. As a result of in the changes in temperature and moisture, the membrane, GDL and bipolar plates will all experience expansion and contraction. Because of the different thermal expansion and swelling coefficients between these materials, hygro-thermal stresses are introduced into the unit cell during operation. In addition, the non-uniform current and reactant flow distributions in the cell result in non-uniform temperature and moisture content of the cell which could in turn, potentially causing localized increases in the stress magnitudes, and this leads to mechanical damage, which can appear as through-the-thickness flaws or pinholes in the membrane, or delaminating between the polymer membrane and gas diffusion layers. Therefore, in order to acquire a complete understanding of these damage mechanisms in the membranes and gas diffusion layers, mechanical response under steady-state hygro-thermal stresses should be studied under real cell operation conditions. A three-dimensional, multi–phase, non-isothermal computational fluid dynamics model of a planar ambient air-breathing, proton exchange membrane fuel cell has been developed and used to study the effects of ambient conditions on the temperature distribution, displacement, deformation, and stresses inside the cell. The behaviour of the fuel cell during operation has been studied and investigated under real cell operating conditions. A unique feature of the present model is to incorporate the effect of mechanical, hygro and thermal stresses into actual three-dimensional fuel cell model. The results show

  16. Design and analysis of the NFIRAOS thermal optics enclosure

    Science.gov (United States)

    Fitzsimmons, Joeleff; Andersen, David; Atwood, Jenny; Byrnes, Peter; Herriot, Glen; Hill, Alexis; Szeto, Kei

    2016-08-01

    The Narrow Field InfraRed Adaptive Optics System (NFIRAOS) will be the first-light facility adaptive optics system for the Thirty Meter Telescope (TMT). In order to meet the optical performance and stability specifications essential to leveraging the extraordinary capabilities of the TMT, all of the optical components within NFIRAOS will be protected within a large thermally-controlled optics enclosure (ENCL). Among the many functions performed by the ENCL, the most critical functions include providing a highly stable, light-tight, cold, dry environment maintained at 243±0.5 K for the NFIRAOS opto-mechanical sub-systems and supporting TABL structure. Although the performance of the ENCL during the science operation of NFIRAOS is critical, the maximum thermal loading will be defined by the cooldown/ warm-up cycle which must be accomplished within a time-frame that will minimize the on-sky operational impact due to daytime maintenance work. This study describes the thermal/mechanical design development and supporting analyses (analytical and finite element analyses (FEA)) completed during the preliminary design phase and through the current progression of the ENCL final design phase. The walls of the ENCL consist of interlocking, multilayered, thermally insulated panels, which are supported by an externally located structural framework which attaches to the NFIRAOS Instrument Support Structure. The regulation of the interior ENCL wall surface temperature to within ±0.5 K requires that the heat flux into the interior of NFIRAOS be eliminated by cooling a thermal conduction plate embedded between multiple layers of insulation. The thermal design of the enclosure was evaluated for both steady-state (SS) performance and transient performance (cool-down and warm-up cycles). The transient analysis utilizes a hybrid of a one-dimensional thermal network approach combined with three-dimensional conjugate heat transfer analyses of explicit opto-mechanical components within

  17. Internal insulation applied in heritage multi-storey buildings with wooden beams embedded in solid masonry brick facades

    DEFF Research Database (Denmark)

    Harrestrup, Maria; Svendsen, Svend

    2016-01-01

    The use of internal insulation is investigated in a heritage building block with wooden beam construction and masonry brick walls as part of an energy renovation. Measurements were carried out and compared to results from a hygrothermal simulation model. The risk of mould growth in the wooden beams...... and in the interface between the insulation and the brick wall was evaluated. Three different insulation strategies for applying internal insulation were investigated: 1) insulation applied on the entire interior facade; 2) 200 mm gap in the insulation above the floor; and 3) 200 mm gap in the insulation both above...

  18. Moisture ingress into electronics enclosures under isothermal conditions

    Energy Technology Data Exchange (ETDEWEB)

    Staliulionis, Ž.; 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

    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.

  19. Evidence of polyandry for Aedes aegypti in semifield enclosures.

    Science.gov (United States)

    Helinski, Michelle E H; Valerio, Laura; Facchinelli, Luca; Scott, Thomas W; Ramsey, Janine; Harrington, Laura C

    2012-04-01

    Female Aedes aegypti are assumed to be primarily monandrous (i.e., mate only once in their lifetime), but true estimates of mating frequency have not been determined outside the laboratory. To assess polyandry in Ae. aegypti with first-generation progeny from wild mosquitoes, stable isotope semen-labeled males ((15)N or (13)C) were allowed to mate with unlabeled females in semifield enclosures (22.5 m(3)) in a dengue-endemic area in southern Mexico. On average, 14% of females were positive for both labels, indicating that they received semen from more than one male. Our results provide evidence of a small but potentially significant rate of multiple mating within a 48-hour period and provide an approach for future open-field studies of polyandry in this species. Polyandry has implications for understanding mosquito ecology, evolution, and reproductive behavior as well as genetic strategies for mosquito control.

  20. Moisture ingress into electronics enclosures under isothermal conditions

    DEFF Research Database (Denmark)

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

    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...

  1. Third millennium BC ditched enclosures in central Iberia

    Directory of Open Access Journals (Sweden)

    Díaz del Río, Pedro

    2003-12-01

    Full Text Available This article examines contextual data from three Copper Age ditched enclosures excavated between 1997 and 2001 in the middle Tagus basin. Calibrated radiocarbon dates suggest that they were all constructed and backfilled during the first half of the third millennium BC. Key characteristics are their heterogeneous topographic position, variable visibility, small size and high density of features and domestic refuse. All evidence supports their interpretation as small occupation sites. Finally, we discuss the role of ditched enclosures in their contemporary regional and Iberian context. We suggest that their variability is a result of diverse aggregation and fission dynamics characterisitic of segmentary societies.

    Este trabajo presenta la primera información contextual de tres recintos de fosos calcolíticos excavados entre 1997 y 2001 en el valle medio del Tajo (Comunidad de Madrid. La serie de dataciones absolutas de dos de ellos indica que fueron construidos y colmatados en la primera mitad del III milenio cal AC. Se trata de recintos de pequeño tamaño, heterogéneos en cuanto a su posición topográfica, variables respecto a su arco de visibilidad y con escasa racionalidad defensiva. Todo el registro apunta a espacios habitados de forma permanente. Por último se discute el papel de los recintos de fosos en el contexto regional y Peninsular. Sugerimos que su variabilidad es el resultado de distintas dinámicas de agregación y fisión características de sociedades segmentarias.

  2. Thermal Performance of Hollow Clay Brick with Low Emissivity Treatment in Surface Enclosures

    Directory of Open Access Journals (Sweden)

    Roberto Fioretti

    2014-10-01

    Full Text Available External walls made with hollow clay brick or block are widely used for their thermal, acoustic and structural properties. However, the performance of the bricks frequently does not conform with the minimum legal requirements or the values required for high efficiency buildings, and for this reason, they need to be integrated with layers of thermal insulation. In this paper, the thermal behavior of hollow clay block with low emissivity treatment on the internal cavity surfaces has been investigated. The purpose of this application is to obtain a reduction in the thermal conductivity of the block by lowering the radiative heat exchange in the enclosures. The aims of this paper are to indicate a methodology for evaluating the thermal performance of the brick and to provide information about the benefits that should be obtained. Theoretical evaluations are carried out on several bricks (12 geometries simulated with two different thermal conductivities of the clay, using a finite elements model. The heat exchange procedure is implemented in accordance with the standard, so as to obtain standardized values of the thermal characteristics of the block. Several values of emissivity are hypothesized, related to different kinds of coating. Finally, the values of the thermal transmittance of walls built with the evaluated blocks have been calculated and compared. The results show how coating the internal surface of the cavity provides a reduction in the thermal conductivity of the block, of between 26% and 45%, for a surface emissivity of 0.1.

  3. 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

    2013-05-01

    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.

  4. The permanent total enclosure: A useful tool in pollution prevention and streamlined regulatory permitting

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, S.C. [Eckenfelder Inc., Greenville, SC (United States)

    1997-12-31

    In today`s competitive work environment it is becoming increasingly important for industry to comply with environmental regulations and standards while minimizing cost on pollution control systems. This often requires innovative new solutions to existing environmental challenges. Strategic environmental planning and process optimization are key elements in cost-effective environmental management. The permanent total enclosure can be a useful tool in the strategic environmental planning process. This paper discusses the installation of a permanent total enclosure at a southeastern printing and publishing industry. By constructing the total enclosure the industry was able to streamline the permitting process and reduce pollutant emissions while simultaneously reducing cost and saving money.

  5. Construction and validation of a systematic ethogram of Macaca fascicularis in a free enclosure.

    Science.gov (United States)

    Xu, Fan; Xie, Liang; Li, Xin; Li, Qi; Wang, Tao; Ji, Yongjia; Kong, Fei; Zhan, Qunlin; Cheng, Ke; Fang, Liang; Xie, Peng

    2012-01-01

    Behavioral studies in non-human primates have become ideal models for further investigations into advanced cognitive function in humans. To date, there is no systematic ethogram of the cynomolgus monkey (Macaca fascicularis) in a free enclosure. In a field observation of 6012 subjects, 107 distinct behaviors of M. fascicularis were preliminarily described. 83 of these behaviors were then independently validated through a randomized cohort and classified into 12 behavioral categories. 53 of these behaviors were then selected to accurately reflect the daily mundane activity of the species in a free enclosure. These findings systematically document the behavior of M. fascicularis in a free enclosure for use in further investigations.

  6. Construction and validation of a systematic ethogram of Macaca fascicularis in a free enclosure.

    Directory of Open Access Journals (Sweden)

    Fan Xu

    Full Text Available Behavioral studies in non-human primates have become ideal models for further investigations into advanced cognitive function in humans. To date, there is no systematic ethogram of the cynomolgus monkey (Macaca fascicularis in a free enclosure. In a field observation of 6012 subjects, 107 distinct behaviors of M. fascicularis were preliminarily described. 83 of these behaviors were then independently validated through a randomized cohort and classified into 12 behavioral categories. 53 of these behaviors were then selected to accurately reflect the daily mundane activity of the species in a free enclosure. These findings systematically document the behavior of M. fascicularis in a free enclosure for use in further investigations.

  7. Monitoring water storage variations with a superconducting gravimeter in a field enclosure

    Science.gov (United States)

    Güntner, Andreas; Mikolaj, Michal; Reich, Marvin; Schröder, Stephan; Wziontek, Hartmut

    2016-04-01

    Water storage dynamics are notoriously difficult to monitor in a comprehensive way beyond the point scale. Superconducting gravimeters (SG) measure temporal variations of the Earth's acceleration of gravity with very high precision and temporal resolution. They have been shown to be sensitive to mass variations induced by hydrological processes in their surroundings, typically within a radius of few 100 meters around the instrument. Thus, in turn, SGs are unique instruments for monitoring water storage variations in the landscape in an integrative way, accounting for soil moisture, vadose zone and groundwater storage, snow, and surface water bodies if existent. Nevertheless, hydrological applications of SGs so far have usually been hindered by the instruments being located in observatory buildings. This infrastructure disturbs the local hydrology and causes many uncertainties due to the often poorly known geometry of the construction, non-natural flow paths of water, and unknown water storage variations below and/or on top of the infrastructure. By deploying the SG in a small enclosure, these disturbances and unknowns are minimized. We report on the first experiences with exposing a SG of the latest generation (iGrav) in a small housing of less than 1 m2 footprint to temperate hydro-meteorological conditions. The system has been set up on a grassland site at the Geodetic Observatory in Wettzell, Bavarian Forest, Germany, in early 2015. We present the technical layout and challenges in running the gravimeter system. Additionally, we report on the quality of data acquired so far and present comparisons to in-situ soil moisture monitoring with TDR and TOMST sensors, a lysimeter, and groundwater observations, and two SGs located in nearby observatory buildings. We discuss the value of SG observations for estimating water storage variations, evapotranspiration and groundwater recharge beyond the point scale.

  8. 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)

  9. Liquid-mixed convection in a closed enclosure with highly-intensive heat fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Rivas-Cardona, A.; Hernandez-Guerrero, A. [Universidad de Guanajuato, Facultad de Ingenieria Mecanica, Electrica y Electronica, Salamanca, Guanajuato (Mexico); Romero-Mendez, R. [Universidad Autonoma de San Luis Potosi, Facultad de Ingenieria, San Luis Potosi (Mexico); Lesso-Arroyo, R. [Instituto Tecnologico de Celaya, Dept. de Ingenieria Mecanica, Celaya Gto. (Mexico)

    2004-09-01

    Laminar-mixed convection of a dielectric fluid contained in a two-dimensional enclosure is investigated in the present paper. Within the enclosure discrete heat sources of a constant heat flux are flush-mounted on a vertical wall. Forced flow conditions are imposed by placing a propeller at different locations within the enclosure. The analysis is performed for a wide range of heat fluxes, from the order of 10,000 to 100,000 W/m{sup 2}, way in the trend of current computer chips, such as the Pentium IV, and the future ones. Emphasis is placed on the influence of the governing parameters, such as buoyancy parameters, the aspect ratio of the enclosure, and location of the propeller. The flow and temperature fields are obtained as part of the solution. (Author)

  10. Enhancement of natural ventilation in rectangular enclosure with two openings by thin fin

    Institute of Scientific and Technical Information of China (English)

    YANG Yi; DENG Qi-hong

    2005-01-01

    A numerical method was used to study the natural ventilation in a rectangular enclosure with two symmetrical openings. In order to improve the natural ventilation efficiency, a fin was introduced into the enclosure.Steady-state heat transfer by laminar natural ventilation in a partially divided rectangular enclosure was investigated by numerically solving equations of mass, momentum and energy. Streamlines and isotherms were produced and heat transfer rate were calculated. A parametric study was carried out using the following parameters: Rayleigh number (1 × 103 - 1 × 106) , dimensionless length (0 - 0.7) and position values (-0. 7 - 0. 7). It is found that the Nusselt number is an increasing function of Rayleigh number. By comparing with no-fin case, it is concluded that fin can effectively enhance the natural ventilation in the enclosure.

  11. 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.

  12. Discussion on the Network Method for Calculating Radiant Interchange Within an Enclosure

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    In this paper the Δ-Y transformation of a linear electric circuit is introduced to simplify the computation of net radiant heat exchange on a surface of an enclosure with three surfaces.The illustration of the transformation is given by solving six problems taken from the textbooks.Some discussion concerning the possibility of extending the transformation method to enclosures with more than three surfaces,and the condition for applying the network method are also presented.

  13. NUMERICAL ANALYSIS OF NATURAL CONVECTION IN A PRISMATIC ENCLOSURE

    Directory of Open Access Journals (Sweden)

    Walid AICH

    2011-01-01

    Full Text Available Natural convection heat transfer and fluid flow have been examined numerically using the control-volume finite-element method in an isosceles prismatic cavity, submitted to a uniform heat flux from below when inclined sides are maintained isothermal and vertical walls are assumed to be perfect thermal insulators, without symmetry assumptions for the flow structure. The aim of the study is to examine a pitchfork bifurcation occurrence. Governing parameters on heat transfer and flow fields are the Rayleigh number and the aspect ratio of the enclosure. It has been found that the heated wall is not isothermal and the flow structure is sensitive to the aspect ratio. It is also found that heat transfer increases with increasing of Rayleigh number and decreases with increasing aspect ratio. The effects of aspect ratio become significant especially for higher values of Rayleigh number. Eventually the obtained results show that a pitchfork bifurcation occurs at a critical Rayleigh number, above which the symmetric solutions becomes unstable and asymmetric solutions are instead obtained.

  14. 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.

  15. Persistence and distribution of 4-nonylphenol in water, sediment, macrophytes, and wall material of littoral enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Heinis, L.J.; Tunell, R.; Liber, K. [Univ. of Wisconsin, Superior, WI (United States). Lake Superior Research Inst.; Knuth, M.L. [Environmental Protection Agency, Duluth, MN (United States). Environmental Research Lab.

    1994-12-31

    Eighteen enclosures (5 m x 10 m) were constructed in the littoral zone of a 2-ha pond near Duluth, MN. Each enclosure consisted of 5 m of natural shoreline and three walls of an inert plastic. The enclosures had an average surface area of 31.9 m{sup 2} , an average depth of 0.6 m and an average water volume of 33.1 m{sup 3}. The enclosure waters were treated with the alkyl phenol ethoxylate precursor and degradation product 4-nonylphenol. Application was accomplished by sub-surface injection over a 20-day period with a 2 day frequency. Nominal aqueous concentrations were 0, 3, 30, 100 and 300 {mu}g/L. Concentrations of 4-nonylphenol were monitored during and after application in the water, sediment, macrophytes, and enclosure wall material. Average maximum water concentrations ranged from 96.5% of nominal to 62.0% of nominal and average minimum water concentrations ranged from 33.3% of nominal to 29.5% of nominal during the application period. Water concentrations decreased exponentially after application ended. Sediment concentrations during the application period were constant from 8 to 20 d and peak concentrations occurred 48 d after application began. Macrophyte concentrations peaked 21 d after initial application with a steady decline through 76 d. Enclosure wall material concentrations reached a peak 3 h before the final application. A gradual decline occurred until 34 d after initial application followed by a more rapid dissipation.

  16. Field Trial of an Aerosol-Based Enclosure Sealing Technology

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, Curtis [Univ. of California, Davis, CA (United States); Springer, David [Univ. of California, Davis, CA (United States)

    2015-09-01

    This report presents the results from several demonstrations of a new method for sealing building envelope air leaks using an aerosol sealing process developed by the Western Cooling Efficiency Center at UC Davis. The process involves pressurizing a building while applying an aerosol sealant to the interior. As air escapes through leaks in the building envelope, the aerosol particles are transported to the leaks where they collect and form a seal that blocks the leak. Standard blower door technology is used to facilitate the building pressurization, which allows the installer to track the sealing progress during the installation and automatically verify the final building tightness. Each aerosol envelope sealing installation was performed after drywall was installed and taped, and the process did not appear to interrupt the construction schedule or interfere with other trades working in the homes. The labor needed to physically seal bulk air leaks in typical construction will not be replaced by this technology. However, this technology is capable of bringing the air leakage of a building that was built with standard construction techniques and HERS-verified sealing down to levels that would meet DOE Zero Energy Ready Homes program requirements. When a developer is striving to meet a tighter envelope leakage specification, this technology could greatly reduce the cost to achieve that goal by providing a simple and relatively low cost method for reducing the air leakage of a building envelope with little to no change in their common building practices.

  17. NATURAL CONVECTION IN PASSIVE SOLAR BUILDINGS: EXPERIMENTS, ANALYSIS AND RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Gadgil, A.; Bauman, F.; Kammerud, R.

    1981-04-01

    Computer programs have been developed to numerically simulate natural convection in two- and three-dimensional room geometries. The programs have been validated using published data from the literature, results from a full-scale experiment performed at the Massachusetts Institute of Technology, and results from a small-scale experiment performed at LBL. One of the computer programs has been used to study the influence of natural convection on the thermal performance of a single zone in a direct-gain passive solar building. It is found that the convective heat transfer coefficients between the air and the enclosure surfaces can be substantially different from the values assumed in the standard building energy analysis methods, and can exhibit significant variations across a given surface. This study implies that the building heating loads calculated by standard building energy analysis methods may have substantial errors as a result of their use of common assumptions regarding the convection processes which occur in an enclosure.

  18. Field Trial of an Aerosol-Based Enclosure Sealing Technology

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, Curtis [Univ. of California, Davis, CA (United States); Springer, David [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States)

    2015-09-01

    This report presents the results from several demonstrations of a new method for sealing building envelope air leaks using an aerosol sealing process developed by the Western Cooling Efficiency Center at UC Davis. The process involves pressurizing a building while applying an aerosol sealant to the interior. As air escapes through leaks in the building envelope, the aerosol particles are transported to the leaks where they collect and form a seal that blocks the leak. Standard blower door technology is used to facilitate the building pressurization, which allows the installer to track the sealing progress during the installation and automatically verify the final building tightness. Each aerosol envelope sealing installation was performed after drywall was installed and taped, and the process did not appear to interrupt the construction schedule or interfere with other trades working in the homes. The labor needed to physically seal bulk air leaks in typical construction will not be replaced by this technology.

  19. Two-Dimensional Transient Modeling of Energy and Mass Transfer in Porous Building Components using COMSOL Multiphysics

    Directory of Open Access Journals (Sweden)

    Mustapha Maliki

    2017-01-01

    Full Text Available This paper reports on a transient heat, air and moisture transfer (HAM model. The governing partial-differential equations are simultaneously solved for temperature and capillary pressure through multi-layered porous media, including the non-linear transfer and storage properties of materials. Using partial differential equations functions, some thermo-physical properties of porous media are converted into coefficients depending on temperature and capillary pressure. Major features of the model are multi-dimensional and transient coupling of heat, air and moisture transport. The coupled equations are solved using the COMSOL Multiphysics time-dependent solver. This solver enables HAM (Heat, Air, Moisture modeling in porous media. Besides, the good agreements obtained with a 2D benchmark suggest that the model can be used to assess the hygrothermal performance of building envelope components. This paper concludes that the total heat flux in the insulated wall represents only the quarter of that crossing the uninsulated concrete roof. On the other hand, the concrete having the lowest water vapour permeability of all used materials allows maintaining the vapour pressure levels close to the initial value (103 Pa. This induces a situation of interstitial condensation within the concrete of the roof. Being able to evaluate the hygrothermal behaviour, the proposed model may turn out to be a valuable tool to solve other building problems.

  20. A CFD study of hygro-thermal stresses distribution in tubular-shaped ambient air-breathing PEM micro fuel cell during regular cell operation

    Directory of Open Access Journals (Sweden)

    Maher A.R. Sadiq Al-Baghdadi

    2010-03-01

    Full Text Available The need for improved lifetime of air-breathing proton exchange membrane (PEM fuel cells for portable applications necessitates that the failure mechanisms be clearly understood and life prediction models be developed, so that new designs can be introduced to improve long-term performance. An operating air-breathing PEM fuel cell has varying local conditions of temperature, humidity. As a result of in the changes in temperature and moisture, the membrane, GDL and bipolar plates will all experience expansion and contraction. Because of the different thermal expansion and swelling coefficients between these materials, hygro-thermal stresses are introduced into the unit cell during operation. In addition, the non-uniform current and reactant flow distributions in the cell result in non-uniform temperature and moisture content of the cell which could in turn, potentially causing localized increases in the stress magnitudes, and this leads to mechanical damage, which can appear as through-the-thickness flaws or pinholes in the membrane, or delaminating between the polymer membrane and gas diffusion layers. Therefore, in order to acquire a complete understanding of these damage mechanisms in the membranes and gas diffusion layers, mechanical response under steady-state hygro-thermal stresses should be studied under real cell operation conditions. A three-dimensional, multi–phase, non-isothermal computational fluid dynamics model of a novel, tubular, ambient air-breathing, proton exchange membrane micro fuel cell has been developed and used to investigate the displacement, deformation, and stresses inside the whole cell, which developed during the cell operation due to the changes of temperature and relative humidity. The behaviour of the fuel cell during operation has been studied and investigated under real cell operating conditions. In addition to the new and complex geometry, a unique feature of the present model is to incorporate the effect of

  1. The improvement of the hygrothermal and mechanical properties of bismaleimide and K3B/IM7 carbon-fiber composites through a systematic study of the interphase

    Science.gov (United States)

    Wilenski, Mark Stewart

    Advanced aircraft travel at speeds in excess of mach 2 result in external skin temperatures ranging from {-}60sp°C to +190sp°C with extreme heating and cooling rates in the presence of moisture. This combination of environments presents a challenge to current materials. IM7 carbon fiber composites made with either bismaleimide (a thermoset) or K3B (a thermoplastic polyimide) resin are being considered for this use. The overall objective of this research was to develop a greater understanding of both the macroscopic response of these materials to hygrothermal and thermal spike environments, as well as the molecular level interactions which affect the ability of the resins to bond to the fiber. Hygrothermal testing of BMI/IM7 composites showed that resin properties are reduced by the presence of moisture while composite properties are virtually unaffected. Exposure of composites to a relatively small number of thermal spikes between room temperature and 250sp°C was shown to have little effect on BMI/IM7 composites, but causes excessive blistering of wet K3B/IM7 composites. A macroscopic microcracking phenomenon is observed in cross-ply laminates of the BMI/IM7 system. This was shown to be due to the generation of thermal residual stresses formed during cool down from a "stress-free temperature." Both finite element and analytical models were utilized to analyze the causes of this microcracking with a focus on methods for minimizing the resultant stresses. Several methods with potential were identified and suggestions for future work are made. Microscopically, tests of the bond strength between both the BMI and K3B resins with the unsized IM7 fiber indicated that the adhesion was low. Experimentation on the BMI/IM7 system was able to identify that the only active adhesion promoting mechanism was mechanical interlocking and not chemical bonds between functionalities on the fiber surface and the resin. Various methods for improving the adhesion in the BMI/IM7 system

  2. 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.

  3. Natural convection of ferrofluids in partially heated square enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Selimefendigil, Fatih, E-mail: fatih.selimefendigil@cbu.edu.tr [Department of Mechanical Engineering, Celal Bayar University, 45140 Manisa (Turkey); Öztop, Hakan F., E-mail: hfoztop1@gmail.com [Department of Mechanical Engineering, Technology Faculty, Fırat University, 23119 Elazığ (Turkey); Al-Salem, Khaled, E-mail: kalsalem@ksu.edu.sa [Department of Mechanical Engineering, College of Engineering, King Saud University, Riyadh (Saudi Arabia)

    2014-12-15

    In this study, natural convection of ferrofluid in a partially heated square cavity is numerically investigated. The heater is located to the left vertical wall and the right vertical wall is kept at constant temperature lower than that of the heater. Other walls of the square enclosure are assumed to be adiabatic. Finite element method is utilized to solve the governing equations. The influence of the Rayleigh number (10{sup 4}≤Ra≤5×10{sup 5}), heater location (0.25H≤y{sub h}≤0.75H), strength of the magnetic dipole (0≤γ≤2), horizontal and vertical location of the magnetic dipole (−2H≤a≤−0.5H, 0.2H≤b≤0.8H) on the fluid flow and heat transfer characteristics are investigated. It is observed that different velocity components within the square cavity are sensitive to the magnetic dipole source strength and its position. The length and size of the recirculation zones adjacent to the heater can be controlled with magnetic dipole strength. Averaged heat transfer increases with decreasing values of horizontal position of the magnetic dipole source. Averaged heat transfer value increases from middle towards both ends of the vertical wall when the vertical location of the dipole source is varied. When the heater location is changed, a symmetrical behavior in the averaged heat transfer plot is observed and the minimum value of the averaged heat transfer is attained when the heater is located at the mid of vertical wall. - Highlights: • Free convection of ferrofluids in a partially heated cavity is numerically studied. • Velocities are sensitive to the magnetic dipole source strength and its position. • Averaged Nu increases with decreasing x-location values of the magnetic dipole. • Averaged Nu increases from middle towards ends when y-location of dipole changes.

  4. Aquaculture enclosures relate to the establishment of feral populations of introduced species.

    Directory of Open Access Journals (Sweden)

    Xuan Liu

    Full Text Available Many species introduced by humans for social and economic benefits have invaded new ranges by escaping from captivity. Such invasive species can negatively affect biodiversity and economies. Understanding the factors that relate to the establishment of feral populations of introduced species is therefore of great importance for managing introduced species. The American Bullfrog (Lithobates catesbeianus is one species that has escaped from farms, and it is now found in the wild in China. In this study, we examined influences of two types of bullfrog farm (termed simple and elaborate farm enclosures on the establishment of feral populations of this species in 137 water bodies in 66 plots in four provinces of China. The likelihood of establishment of bullfrog populations in water bodies in plots with simple enclosures (49/89 = 55.1% was higher than those with elaborate enclosures (3/48 = 6.3%. Based on the Akaike Information Criterion, the minimum adequate model of generalized linear mixed models with a binomial error structure and a logit link function showed that the establishment or failure of bullfrog populations in water bodies was positively correlated with the presence of a simple enclosure, the number of bullfrogs raised and the presence of permanent water in a plot, but negatively correlated with distance from a bullfrog farm and the occurrence of frequent hunting. Results therefore suggest that a simple farm enclosure can increase the establishment of feral bullfrog populations compared with an elaborate enclosure. Our findings are the first to quantify the importance of improving farming enclosures to control and minimize the risk from introduced species.

  5. Laboratory Testing of Aerosol for Enclosure Air Sealing

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, C.; Modera, M.

    2012-05-01

    Space conditioning energy use can be significantly reduced by addressing uncontrolled infiltration and exfiltration through the envelope of a building. A process for improving the air tightness of a building envelope by sealing shell leaks with an aerosol sealing technology is presented. Both retrofit and new construction applications are possible through applying this process either in attics and crawlspaces or during rough-in stage.

  6. The impact of hygrothermal preconditioning on mode II interlaminar fracture toughness in unidirectional carbon fiber reinforced epoxy composites: An experimental investigation

    Science.gov (United States)

    Hempowicz, Michael L.

    The correlation between the interlaminar Mode II fracture toughness (GIIC) of a carbon fiber reinforced epoxy and other material properties across different conditioning regimes was investigated. Specimens were preconditioned using select hygrothermal criteria to evaluate how changes in the material and mechanical properties in a carbon fiber/epoxy composite correlations with changes in GIIC for each regime. An increase in GIIC from baseline values was demonstrated across all conditions from end-notched flexure (ENF) testing. Dynamic mechanical analysis (DMA) and tensile tests had varying responses based on preconditioning environment. Since tensile and some DMA properties rely on fiber strength and show property loss with increased plasticization, fiber strength may not have a large impact on GIIC properties. Test data also implied that the GIIC increased when consolidation of the polymer chains occurred in the arid condition as well as when crosslink density increased in the moisture exposed conditions. From these results it is believed that the chemical and physical changes in matrix cohesion are more important to GIIC behavior prediction than fiber behavior.

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

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Je-Young; Chung, Bum-Jin [Kyung Hee University, Yongin (Korea, Republic of)

    2016-10-15

    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{sup 3} and 1.20x10{sup 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.

  8. 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.

  9. Experimental Study of Melting Heat Transfer in an Enclosure with Three Discrete Protruding Heat Sources

    Institute of Scientific and Technical Information of China (English)

    YonglinJu; ZhongqiChen; 等

    1998-01-01

    To explore the possibility of using solid-liquid phase change cooling to those periodically or intermittently operated electronic equipment,a detail of experimental study of time-dependent melting heat transfer in a rectangular enclosure with three discrete proturding heat sources is presented.A series of experimental measurement in an enclosure with phase change materials (PCM)of n-octadecane of experimental measurement in an enclosure with phase change materials(PCM) of -octadecane heated by three discrete protruding heat sources at a constant rate on one of its vertical wall has been described.The opposite wall of the enclosure is cooled at a constant temperature and all other walls of the enclosure are insulated.The time-dependent solid-liquid shapes of the interface during melting process,the variation of surface temperature and the effects of sulbcooling are investigated.An empirical correlation predicting the relationship between the liquid phase fraction and subcooling is given.

  10. 浅析英国议会圈地运动%On British Parliamentary Enclosure Movement

    Institute of Scientific and Technical Information of China (English)

    孙连娣

    2013-01-01

    议会圈地运动是英国在资产阶级掌握政权以后通过议会颁布相关的法案,以合法形式大规模圈占土地的过程。本文首先将议会圈地与早期圈地相比较,从而引出议会圈地运动所产生的原因、条件、过程和影响五个方面,为进一步论证议会圈地是小农土地所有者消亡的一个重要原因提供了史料依据。%Parliamentary Enclosure Movement is Britain after bourgeois power through Parliament enacted relevant legislation, to process legitimate form of massive encirclements within them. This paper will firstly compared parliamentary enclosure with the early enclosure, which led to Parliamentary Enclosure Movement generated conditions, process and effect five aspects reasons, in order to further demonstrate the historical evidence of parliamentary enclosure is one of the important reasons of peasant land owners.

  11. On Identical Problems of Natural Convection in Enclosures and APplications of the Identity Character

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    In this paper,a concept of “identical problems”of natural convection in enclosures is presented.A pair of problems of natural conyection in enclosures is said to be identical if they look different in appearance but with appropriate selection of coordinates and appropriate definition of dimensionless variables for each problem;they will have identical geometric configurations and identical dimensionless governing equations and related boundary conditions,The identical characteristics of a pair of problems of natural convection in enclosures with an interanl isolated island are demonstrated via dimensionless mathematical formulation and flow visualization results.Numericasl computations are performed and the predicted streamlines agree with the flow visualization results.A number of other possible pairs of identical problems are also presented.Applications of the identical character are provided and assumptions under which the identical problems may exist are discussed.

  12. Space use as an indicator of enclosure appropriateness in African wild dogs (Lycaon pictus).

    Science.gov (United States)

    Hunter, Sally C; Gusset, Markus; Miller, Lance J; Somers, Michael J

    2014-01-01

    A clear understanding of space use is required to more fully understand biological requirements of nonhuman animals in zoos, aid the design of exhibits, and maximize the animals' welfare. This study used electivity indexes to assess space use of two packs of African wild dogs (Lycaon pictus) and the appropriateness of two naturalistic, outdoor enclosures at the San Diego Zoo and Bronx Zoo. The results identified enclosure features that were both underutilized and overutilized. They suggest that replacing underutilized areas with features similar to areas that were overutilized may provide more preferred opportunities for the animals. Assessing space use of animals in human care may serve as an indicator of enclosure appropriateness and could have welfare implications. By looking at the possible reasons for area preferences, animal managers can get an idea of where improvements could be made. Designing future exhibits accordingly thus can provide possible welfare benefits for the animals concerned.

  13. Radiation heat exchange between electronic components on a circuit board and the walls of its enclosure

    Energy Technology Data Exchange (ETDEWEB)

    Wu, W.; Cengel, Y.A. (Univ. of Nevada, Reno, NV (United States))

    Radiation heat transfer between rectangular electronic components on a printed circuit board and the walls of its enclosure is studied analytically using a Monte Carlo method. The radiation heat transfer between the electronic components and the cover is determined for the cases of diffuse and specular surfaces with constant properties, and for diffuse and specular surfaces with variable temperature and direction-dependent properties. The radiation interchange between the components and the cover of the enclosure are determined and presented for various dimensionless parameters and surface emissivities in tabular and graphical forms. The radiation heat transfer, in general, is found to be comparable in magnitude to natural-convection heat transfer at operating conditions encountered in practice. It is shown that radiation can serve as an effective heat transfer mechanism for the cooling of electronic components in sealed enclosures cooled externally.

  14. Implementation and control of asymmetric thermal environment in two-dimensional rectangular enclosure

    Institute of Scientific and Technical Information of China (English)

    SHEN Lin; DENG Qi-hong

    2005-01-01

    Laminar natural convection in an enclosure divided by an adiabatic partition on its bottom with two unequal discrete heat sources was investigated numerically. The effect of the partition on the flow structure and heat transfer characteristics in enclosure under asymmetric heating condition was studied. The parameters are the Rayleigh number (1 × 104 ≤Ra≤1 × 106) and the height of partition (0≤h/H≤0. 70). The streamlines are produced for various Rayleigh numbers. The results reflected by variations of the average Nusselt number in terms of the height of partition illustrates the convection heat transfer in the enclosure. The role of the partition is to weaken or cut off the heat removal rate from the strong heat source to the weak heat source. It is analyzed that the optimum height of the partition to break the linkage between the strong and weak heat source increases with increasing Rayleigh number.

  15. Numerical studies of convective heat transfer in an inclined semi-annular enclosure

    Science.gov (United States)

    Wang, L.-W.; Chai, A.-T.; Yung, C.-N.; Rashidnia, N.

    1989-01-01

    Natural convection heat transfer in a two-dimensional differentially heated semiannular enclosure is studied. The enclosure is isothermally heated and cooled at the inner and outer walls, respectively. A commercial software based on the SIMPLER algorithm was used to simulate the velocity and temperature profiles. Various parameters that affect the momentum and heat transfer processes were examined. These parameters include the Rayleigh number, Prandtl number, radius ratio, and the angle of inclination. A flow regime extending from conduction-dominated to convection-dominated flow was examined. The computed results of heat transfer are presented as a function of flow parameter and geometric factors. It is found that the heat transfer rate attains a minimum when the enclosure is tilted about +50 deg with respect to the gravitational direction.

  16. Numerical studies of convective heat transfer in an inclined semiannular enclosure

    Science.gov (United States)

    Wang, Lin-Wen; Yung, Chain-Nan; Chai, An-Ti; Rashidnia, Nasser

    1989-01-01

    Natural convection heat transfer in a two-dimensional differentially heated semiannular enclosure is studied. The enclosure is isothermally heated and cooled at the inner and outer walls, respectively. A commercial software based on the SIMPLER algorithm was used to simulate the velocity and temperature profiles. Various parameters that affect the momentum and heat transfer processes were examined. These parameters include the Rayleigh number, Prandtl number, radius ratio, and the angle of inclination. A flow regime extending from conduction-dominated to convection-dominated flow was examined. The computed results of heat transfer are presented as a function of flow parameter and geometric factors. It is found that the heat transfer rate attains a minimum when the enclosure is tilted about +50 deg with respect to the gravitational direction.

  17. Status of cleanliness maintaining in target beam enclosures in SG III facilities and contamination sources analysis

    Science.gov (United States)

    Wang, Meicong; Wang, Baoxu; Miao, Xinxiang; Cheng, Xiaofeng; Wu, Wenkai

    2014-09-01

    In SGIII lasers there are large number of transport mirrors in target beam enclosures. Surface contaminations could easily introduce optical damage, and increase laser energy loss under high laser influence conditions. It is significant for lasers to control contamination and maintain cleanliness. In SGIII prototype, the target beam enclosures are test to be seriously contaminated after about two years of routine operations. Volume cleanliness in mirror boxes are monitored through 24 hours before, during and after a shot. Ingredients of particle and organics are tested. Reconstructions are performed on the mirror boxes to remove debris and keep cleanliness for upward facing surface of mirrors effectively. In SGIII facility some contaminations are found in beam enclosures and on the mirrors after several months of test running. Contaminations sources are analyzed to further know about the contamination mechanisms. Some engineering countermeasures are introduced for controlling contamination and keeping cleanliness for optics.

  18. The Study of a Portable Precision Air Enclosure for Preserving Standard Resistor

    Energy Technology Data Exchange (ETDEWEB)

    Han, B [College of Quality and supervisor technology, Hebei University, Baoding, Hebei Province (China); Tli, X [College of Quality and supervisor technology, Hebei University, Baoding, Hebei Province (China); Zhu, Y [College of Quality and supervisor technology, Hebei University, Baoding, Hebei Province (China)

    2006-10-15

    A novel portable precision air enclosure was designed in this paper. Orthogonalization of the coefficients matrix to decouple the all parts of the control system was attained in theory and heating wires were wound on the surface of the aluminum chamber evenly in construction. Foam plastic was placed between outer and aluminum chamber as thermal insulation. The inner space is 300 mmx250 mmx300 mm, where can fit one SR 102 type resistor or two Tinsley 5685 type resistors. The total weight of the enclosure is about 25kg, which is still a portable one. Its outstanding feature is the temperature difference between top and bottom was offset. Experiment result shows that the monthly inner temperature homogeneity and stability of the enclosure are within 2 mK.

  19. A review on analytical techniques for natural convection investigation in a heated closed enclosure: Case study

    Directory of Open Access Journals (Sweden)

    Minea Alina Adriana

    2015-01-01

    Full Text Available The aim of this paper is to present a theoretical analysis of a few convection problems. The investigations were started from the geometry of a classic muffle manufactured furnace. During this analytical study, different methodologies have been carefully chosen in order to compare and evaluate the effects of applying different analytical methods of the convection heat transfer processes. In conclusion, even if there are available a lot of analytical methods, natural convection in enclosed enclosures can be studied correctly only with numerical analysis. Also, in this article is presented a case study on natural convection application in a closed heated enclosure.

  20. Analytical Formulation for Electromagnetic Leakage Field to Transmission Line Coupling through Covered Apertures of Multiple Enclosures

    Directory of Open Access Journals (Sweden)

    Jianhong Hao

    2017-01-01

    Full Text Available An efficient analytical model has been developed for predicting the electromagnetic leakage field coupling with a lossless two-conductor transmission line (TL through covered apertures of multiple enclosures. The analytical results have been successfully compared with those from the full-wave simulation software CST over a broad frequency range. The analytical model can be employed to analyze the effect of different factors including the position and the direction of the electric dipole, the conductivity of the conductive sheet, the quantity of the aperture, and the direction of the TL on the induced currents. Besides, it can also deal with apertures in multiple sides of the enclosures.

  1. In-situ localized carbon nanotube growth inside partially sealed enclosures

    Directory of Open Access Journals (Sweden)

    Y. van de Burgt

    2013-09-01

    Full Text Available Carbon nanotube assemblies can be used for specific applications such as sensors and filters. We present a method and proof-of-concept to directly grow vertically-aligned carbon nanotube structures within sealed enclosures by means of a feedback-controlled laser-assisted chemical vapor deposition technique. The process is compatible with a variety of micro-fabrication processes and bypasses the need for post-process packaging. Our experiments raise interesting observations related to the gas diffusion dynamics in micro-scale and sub-micron enclosures.

  2. 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.

  3. Analytical modeling of natural convection in a tall rectangular enclosure with multiple disconnected partitions

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Young Min; Kim, Seong Hoon; Seo, Jae Kwang; Kim, Young In [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-08-15

    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.

  4. Laboratory Testing of Aerosol for Enclosure Air Sealing

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, Curtis [Building Industry Research Alliance (BIRA), Stockton, CA (United States); Modera, Mark [Building Industry Research Alliance (BIRA), Stockton, CA (United States)

    2012-05-01

    This report presents a process for improving the air tightness of a building envelope by sealing shell leaks with an aerosol sealing technology. Both retrofit and new construction applications are possible through applying this process either in attics and crawlspaces or during rough-in stage.

  5. Cooling a solar telescope enclosure: plate coil thermal analysis

    Science.gov (United States)

    Gorman, Michael; Galapon, Chriselle; Montijo, Guillermo; Phelps, LeEllen; Murga, Gaizka

    2016-08-01

    The climate of Haleakalā requires the observatories to actively adapt to changing conditions in order to produce the best possible images. Observatories need to be maintained at a temperature closely matching ambient or the images become blurred and unusable. The Daniel K. Inouye Solar Telescope is a unique telescope as it will be active during the day as opposed to the other night-time stellar observatories. This means that it will not only need to constantly match the ever-changing temperature during the day, but also during the night so as not to sub-cool and affect the view field of other telescopes while they are in use. To accomplish this task, plate coil heat exchanger panels will be installed on the DKIST enclosure that are designed to keep the temperature at ambient temperature +0°C/-4°C. To verify the feasibility of this and to validate the design models, a test rig has been installed at the summit of Haleakalā. The project's purpose is to confirm that the plate coil panels are capable of maintaining this temperature throughout all seasons and involved collecting data sets of various variables including pressures, temperatures, coolant flows, solar radiations and wind velocities during typical operating hours. Using MATLAB, a script was written to observe the plate coil's thermal performance. The plate coil did not perform as expected, achieving a surface temperature that was generally 2ºC above ambient temperature. This isn't to say that the plate coil does not work, but the small chiller used for the experiment was undersized resulting in coolant pumped through the plate coil that was not supplied at a low enough temperature. Calculated heat depositions were about 23% lower than that used as the basis of the design for the hillers to be used on the full system, a reasonable agreement given the fact that many simplifying assumptions were used in the models. These were not carried over into the testing. The test rig performance showing a 23% margin

  6. 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

    Building Science Corporation modeled typically well-performing wall assemblies using Wärme und Feuchte instationär (WUFI) Version 5.3 software and demonstrated that these models agree with historic experience when calibrated and modeled correctly. This technical report provides a library of WUFI modeling input data and results. Within the limits of existing experience, this information can be generalized for applications to a broad population of houses.

  7. 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.

  8. 16 CFR 1201.40 - Interpretation concerning bathtub and shower doors and enclosures.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Interpretation concerning bathtub and shower... Policy and Interpretation § 1201.40 Interpretation concerning bathtub and shower doors and enclosures. (a) Purpose and background. The purpose of this section is to clarify the scope of the terms “bathtub...

  9. 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.

  10. 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 f

  11. 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..., Treatment, and Transportation of Marine Mammals Transportation Standards § 3.113 Primary enclosures used to transport marine mammals. No dealer, research facility, exhibitor, or operator of an auction sale shall...

  12. 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...

  13. 9 CFR 3.61 - Primary enclosures used to transport live rabbits.

    Science.gov (United States)

    2010-01-01

    ... live rabbits. 3.61 Section 3.61 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE... and Transportation of Rabbits Transportation Standards § 3.61 Primary enclosures used to transport live rabbits. No person subject to the Animal Welfare regulations shall offer for transportation...

  14. 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

    measurements on the PCBs. Enclosures with smaller opening sizes are observed to have lower relative humidity. Results also show possibility of using heat capacity of materials to store and release heat energy for control of humidity. This paper provides an improved understanding of the effect of internal...

  15. In-situ localized carbon nanotube growth inside partially sealed enclosures

    NARCIS (Netherlands)

    Burgt, Y. van de; Champion, A.; Bellouard, Y.

    2013-01-01

    Carbon nanotube assemblies can be used for specific applications such as sensors and filters. We present a method and proof-of-concept to directly grow vertically-aligned carbon nanotube structures within sealed enclosures by means of a feedback-controlled laser-assisted chemical vapor deposition te

  16. 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…

  17. 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...

  18. 46 CFR 111.83-5 - Bottom entrance and protected enclosures.

    Science.gov (United States)

    2010-10-01

    ... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Shore Connection Boxes § 111.83-5 Bottom entrance and protected enclosures. Each shore connection box must have a bottom entrance for the shore connection cable. The box must provide protection to the shore connection when the connection is in use....

  19. In-situ localized carbon nanotube growth inside partially sealed enclosures

    NARCIS (Netherlands)

    Burgt, Y. van de; Champion, A.; Bellouard, Y.

    2013-01-01

    Carbon nanotube assemblies can be used for specific applications such as sensors and filters. We present a method and proof-of-concept to directly grow vertically-aligned carbon nanotube structures within sealed enclosures by means of a feedback-controlled laser-assisted chemical vapor deposition

  20. Imaging live cell in micro-liquid enclosure by X-ray laser diffraction

    Science.gov (United States)

    Kimura, Takashi; Joti, Yasumasa; Shibuya, Akemi; Song, Changyong; Kim, Sangsoo; Tono, Kensuke; Yabashi, Makina; Tamakoshi, Masatada; Moriya, Toshiyuki; Oshima, Tairo; Ishikawa, Tetsuya; Bessho, Yoshitaka; Nishino, Yoshinori

    2014-01-01

    Emerging X-ray free-electron lasers with femtosecond pulse duration enable single-shot snapshot imaging almost free from sample damage by outrunning major radiation damage processes. In bioimaging, it is essential to keep the sample close to its natural state. Conventional high-resolution imaging, however, suffers from severe radiation damage that hinders live cell imaging. Here we present a method for capturing snapshots of live cells kept in a micro-liquid enclosure array by X-ray laser diffraction. We place living Microbacterium lacticum cells in an enclosure array and successively expose each enclosure to a single X-ray laser pulse from the SPring-8 Angstrom Compact Free-Electron Laser. The enclosure itself works as a guard slit and allows us to record a coherent diffraction pattern from a weakly-scattering submicrometre-sized cell with a clear fringe extending up to a 28-nm full-period resolution. The reconstructed image reveals living whole-cell structures without any staining, which helps advance understanding of intracellular phenomena. PMID:24394916

  1. 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...

  2. 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...

  3. 30 CFR 18.14 - Identification of tested noncertified explosion-proof enclosures.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Identification of tested noncertified explosion-proof enclosures. 18.14 Section 18.14 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... AND ACCESSORIES General Provisions § 18.14 Identification of tested noncertified...

  4. 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...

  5. 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 thermal and moisture management of electronic enclosures are fields of high interest in recent years. It is now generally accepted that the protection of electronic devices is dependent on avoiding critical levels of relative humidity (typically 60–90%) during operations. Leveraging the devel......The thermal and moisture management of electronic enclosures are fields of high interest in recent years. It is now generally accepted that the protection of electronic devices is dependent on avoiding critical levels of relative humidity (typically 60–90%) during operations. Leveraging...... 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...... equivalent RC-circuit models for concentration of water vapor and temperature in the electronic enclosure. After reducing the potential parameter-value space for the critical features using the RC-approach, the optimization strategy uses simpler 2D CFD models of temperature and moisture transport to further...

  6. A Mathematical Images Group Model to Estimate the Sound Level in a Close-Fitting Enclosure

    Directory of Open Access Journals (Sweden)

    Michael J. Panza

    2014-01-01

    Full Text Available This paper describes a special mathematical images model to determine the sound level inside a close-fitting sound enclosure. Such an enclosure is defined as the internal air volume defined by a machine vibration noise source at one wall and a parallel reflecting wall located very close to it and acts as the outside radiating wall of the enclosure. Four smaller surfaces define a parallelepiped for the volume. The main reverberation group is between the two large parallel planes. Viewed as a discrete line-type source, the main group is extended as additional discrete line-type source image groups due to reflections from the four smaller surfaces. The images group approach provides a convergent solution for the case where hard reflective surfaces are modeled with absorption coefficients equal to zero. Numerical examples are used to calculate the sound pressure level incident on the outside wall and the effect of adding high absorption to the front wall. This is compared to the result from the general large room diffuse reverberant field enclosure formula for several hard wall absorption coefficients and distances between machine and front wall. The images group method is shown to have low sensitivity to hard wall absorption coefficient value and presents a method where zero sound absorption for hard surfaces can be used rather than an initial hard surface sound absorption estimate or measurement to predict the internal sound levels the effect of adding absorption.

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    Condensation and moisture related problems are the cause of failures in many cases and consequently serious concerns for reliability in electronics industry. Thus, it is important to control the moisture content and the relative humidity inside electronic enclosures. In this work, a computational...

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

    Science.gov (United States)

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

    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 1.0-110mg/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 46mg/kg. Wipe samples of CCA-wood on which primates sit had dislodgeable As residues of 4.6-111μg/100cm(2), typical of unsealed CCA-wood. Inorganic As doses from animal foods were estimated at 0.22-7.8μg/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 6.37mg/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.

  9. Effects of repeated exposure to 4-nonylphenol on the zooplankton community in littoral enclosures

    Energy Technology Data Exchange (ETDEWEB)

    O`Halloran, S.L.; Liber, K.; Gangl, J.A. [Univ. of Wisconsin, Superior, WI (United States). Lake Superior Research Inst.; Knuth, M.L. [Environmental Protection Agency, Duluth, MN (United States). Mid-Continent Ecology Div.

    1999-03-01

    The effects of 4-nonylphenol (NP) on freshwater zooplankton were evaluated in 18 littoral enclosure mesocosms in northeastern Minnesota. The 18 enclosures were allocated to three blocks of six units with each block including two untreated control enclosures and one enclosure for each of four NP treatments. Treated enclosures received 11 applications of NP over a 20-d period between July 8 and 28, 1993. Maximum NP concentrations measured in the water column 2 h after each application averaged ({+-} SD) 5 {+-} 4, 23 {+-} 11, 76 {+-} 21, and 243 {+-} 41 {micro}g/L over the 11 applications. Nonylphenol dissipated rapidly from the water column but was more persistent in sediments and in/on macrophytes. All cladoceran and copepod taxa were significantly reduced in abundance at 243 {+-} 41 {micro}g/L; some sensitive taxa were also affected by 76 {+-} 21 and 23 {+-} 11 {micro}g/L. While many rotifer taxa were unaffected at any of the test concentrations, several were affected at {ge} 76 {+-} 21 {micro}g/L. Ostracods were only affected at 2,243 {+-} 41 {micro}g/L. No zooplankton taxon was affected at 5 {+-} 4 {micro}g/L. The period of maximum impact usually occurred within 1 to 7 d of the last NP application, and recovery to control abundance levels generally occurred within 7 to 28 d of the last NP application. Two sensitive taxa, Acroperus and Calanoida, did not recover at {ge} 76 {+-} 21 {micro}g/L by the end of the study. The maximum acceptable toxicant concentration for protection of all zooplankton taxa was estimated at {approximately} 10 {micro}g/L, although overall community diversity was unaffected at 23 {+-} 11. The water was the most probable route of NP exposure, but the greater persistence of NP residues in/on macrophytes may have contributed to the lack of recovery of some macrophyte-associated taxa.

  10. Strategy Guideline. 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)

    2016-02-01

    The Strategy Guideline, written by the U.S. Department of Energy's research team Building Science Corporation, 1) describes how to model and interpret results of models for above-grade walls, and 2) analyzes the failure thresholds and criteria for above-grade walls. A library of above-grade walls with historically successful performance was used to calibrate WUFI (Wärme und Feuchte instationär) software models. The information is generalized for application to a broad population of houses within the limits of existing experience.

  11. Monte Carlo simulation of radiation heat transfer in a three-dimensional enclosure containing a circular cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Hong, S.H.; Welty, J.R.

    1999-09-01

    In any process involving high temperatures such as heat treatment, power generation, and other engineering applications, radiation heat transfer is an important mechanism. This paper presents the distribution of radiation heat flux within an enclosure containing a horizontal circular cylinder. Cases were examined both with and without an absorbing, emitting, and scattering medium present. The bottom surface of the square enclosure was considered a uniform heat flux surface, and the other surfaces were considered perfectly absorbing. A circular cylinder was located at various positions along the vertical centerline of the enclosure; its length was that of the enclosure depth. In the first part of this study (cases 1 and 2), different configurations were used with an optically thin ({tau} {much{underscore}lt} 1) medium in the enclosure, and in the second, different optical thicknesses were used with a fixed enclosure size. The amount of radiant energy transferred to the cylinder depends on its location, the optical thickness of the participating medium, and the enclosure depth. For the optically thin cases ({tau} {much{underscore}lt} 1) the Monte Carlo solution calculates geometric view factors.

  12. Evaluation of Moisture Buffer Effects by Performing Whole-Building Simulations

    DEFF Research Database (Denmark)

    Rode, Carsten; Mendes, Nathan; K., Grau

    2004-01-01

    The humidity of rooms and the moisture conditions of materials in the enclosure of buildings depend much on each other because of the moisture exchange that takes place over the interior surfaces. These moisture influences also depend strongly on the thermal conditions of indoor spaces and enclos...

  13. Material characterization models and test methods for historic building materials

    DEFF Research Database (Denmark)

    Hansen, Tessa Kvist; Peuhkuri, Ruut Hannele; Møller, Eva B.

    2017-01-01

    Predictions of long term hygrothermal performance can be assessed by dynamic hygrothermal simulations, in which material parameters are crucial input. Material parameters for especially historic materials are often unknown; therefore, there is a need to determine important parameters, and simple...... ways for estimation of these. A case study of a brick wall was used to create and validate a hygrothermal simulation model; a parameter study with five different parameters was performed on this model to determine decisive parameters. Furthermore, a clustering technique has been proposed to estimate...

  14. Retrofit of a Multifamily Mass Masonry Building in New England

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K.; Kerrigan, P.; Wytrykowska, H.; Van Straaten, R.

    2013-08-01

    Merrimack Valley Habitat for Humanity (MVHfH) has partnered with Building Science Corporation to provide high performance affordable housing for 10 families in the retrofit of an existing brick building (a former convent) into condominiums. The research performed for this project provides information regarding advanced retrofit packages for multi-family masonry buildings in Cold climates. In particular, this project demonstrates safe, durable, and cost-effective solutions that will potentially benefit millions of multi-family brick buildings throughout the East Coast and Midwest (Cold climates). The retrofit packages provide insight on the opportunities for and constraints on retrofitting multifamily buildings with ambitious energy performance goals but a limited budget. The condominium conversion project will contribute to several areas of research on enclosures, space conditioning, and water heating. Enclosure items include insulation of mass masonry building on the interior, airtightness of these types of retrofits, multi-unit building compartmentalization, window selection, and roof insulation strategies. Mechanical system items include combined hydronic and space heating systems with hydronic distribution in small (low load) units, and ventilation system retrofits for multifamily buildings.

  15. 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.

  16. Energy efficiency in multi-story buildings

    Directory of Open Access Journals (Sweden)

    Staritcyna Anastasiia

    2016-01-01

    Full Text Available In this project a research on energy efficiency of Malta house was provided, it is a residential multi-story building in Helsinki, Jätkäsaari area. This project describes introduction with a new heating system for residential dwellings, which uses only heated air. To maintain air temperature in comfort level heat recovery and district heating is used in the same system. The task was to research efficacy of the enclosure structures. For research the 3D model has been created in the program the Revit 2015 and Lumion 13. Thermotechnical calculation for three types of a design has been executed in the program U-value.net.

  17. Hygrothermal adaptability traditional housing in Tampico, Mexico / Adaptabilidad higrotérmica de la vivienda tradicional en Tampico, México

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Fuentes Pérez

    2014-09-01

    Full Text Available The annual increase in the concentration of CO2 in the air is on average 1.5 parts per million, is 0.5% per year, due to the anthropogony generating global climate change, estimates half a century predict a temperature rise of about 2.0°C. The human population is facing an environmental intramural and extramural change in housing. This research aims to determine the degree of hygrothermal adaptability into traditional housing during the year of 2013 in Tampico, Mexico. Depending on the level of scientific knowledge and observation the investigator arrives, makes that labour is diachronic first instance, made as a case study because it analyses the research problem in its genesis and historical conformation with an overview. The thermal behaviour is the thread, therefore, is the methodology to implement multimodal type and by triangulation, since different methods applied provide quantitative and qualitative research approach to the experimental oscillating applied to identify patterns of temperature and relative humidity only, not previously performed in this type of housing. El incremento anual de la concentración de CO2 en el aire es por término medio de 1.5 partes por millón, es decir un 0.5% por año, producto de la antropogenia que genera un cambio climático global, las estimaciones a medio siglo pronostican un aumento de temperatura de unos 2.0°C. La población humana está confrontando un cambio ambiental intramuros y extramuros en la vivienda.La presente investigación tiene como objetivo determinar el grado de adaptabilidad higrotérmica, al interior de la vivienda tradicional durante el año de 2013 en Tampico, México.Según el nivel de conocimiento científico y observación al que llega el investigador, formula que el trabajo es en primera instancia diacrónico, conformado como estudio de caso, porque analiza el problema de investigación en su génesis y conformación histórica con una visión de conjunto. El comportamiento

  18. 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.

  19. Effect of Coating of Earthed Enclosure and Multi-Contaminating Particles on Breakdown Voltage inside Gas Insulated Bus Duct

    National Research Council Canada - National Science Library

    Mousa Awad Allah Abd; Sayed Abo El Souad; Amr Ameen Ezz-El Din

    2014-01-01

    .... This paper demonstrates the control of metallic particles in gas insulated bus duct (GIBD) by using dielectric coating on the inside surface of the outer enclosure of a coaxial electrode system...

  20. On the Use of Computer Algebra Systems and Enclosure Methods in the Modelling and Optimization of Biotechnological Processes

    Directory of Open Access Journals (Sweden)

    Svetoslav Markov

    2005-12-01

    Full Text Available This survey paper aims to promote certain novel mathematical tools, such as computer algebra systems, enclosure methods and interval analysis, to the mathematical modelling and optimization of biotechnological processes.

  1. Microclimatic conditions at the external surface of building envelopes

    Energy Technology Data Exchange (ETDEWEB)

    Kragh, M.K.

    1998-12-31

    The project is described, the motivation for the research and the microclimate is defined in relation to both building physics research and applications. Air temperatur, air humidity, solar radiation and air velocity are briefly considered, whilst driving rain and long-wave radiation are described in more detail. Convective heat transfer and surface coefficients are discussed, although they are not microclimatic factors, merely resulting from combinations of such factors. They are included as they are important in relation to transfer of heat and moisture at the surface of the building envelope. Driving rain measurement is the main area of interest, including development of measurement equipment. Long-wave irradiation is measured and compared with empirical formulae from the literature. Window convection heat transfer is another main area of interest. Nocturnal convective heat transfer from a double pane glazing is studied and measurement principles are discussed. Finally, a compilation of meteorological data for hygrothermal simulations, including estimation of driving rain, is described. System error estimation in relation to the window convection measurements, design notes on an apparatus for external convection measurement, formulae for conversion of relative humitity and dry-bulb temperature into dew point temperature. (EG) 66 refs.

  2. Generalization of a 3-D Acoustic Resonator Model for the Simulation of Spherical Enclosures

    Directory of Open Access Journals (Sweden)

    Dutilleux Pierre

    2001-01-01

    Full Text Available A rectangular enclosure has such an even distribution of resonances that it can be accurately and efficiently modelled using a feedback delay network. Conversely, a nonrectangular shape such as a sphere has a distribution of resonances that challenges the construction of an efficient model. This work proposes an extension of the already known feedback delay network structure to model the resonant properties of a sphere. A specific frequency distribution of resonances can be approximated, up to a certain frequency, by inserting an allpass filter of moderate order after each delay line of a feedback delay network. The structure used for rectangular boxes is therefore augmented with a set of allpass filters allowing parametric control over the enclosure size and the boundary properties. This work was motivated by informal listening tests which have shown that it is possible to identify a basic shape just from the distribution of its audible resonances.

  3. Natural Convection Inside Square Enclosure Containing Equilateral Triangle with Different Orientations

    Directory of Open Access Journals (Sweden)

    Ali Hamza Altaee

    2017-07-01

    Full Text Available Natural convection heat transfer phenomenon in a square enclosure containing equilateral triangle cylinder on its centroid is numerically investigated. Two dimensional for air (Pr=0.71 with outer cold walls of square enclosure and hot inner walls of the triangle cylinder by using CFD techniques is implemented. (Ansys Fluent 16 is used to simulate this problem. TheRayleigh number varied from 104 to 106 and orientation angles from 00 to 1050 step 150 for each case. The laminar boussinesq approximation is used with the convergence criteria less than 10-5 for continuity, momentum and for energy equation 10-8. Fluid and temperature are exhibited by stream and isothermal lines while heat transfer presented by the average Nusselt number. According to orientation angle, results can be divided into two groups; (0o-45o and (60o-105o. Maximum heat transfer obtained at orientation angle of 300 and Ra=106.

  4. Influence of uniform magnetic field on laminar regimes of natural convection in an enclosure

    Science.gov (United States)

    Bondareva, N. S.; Sheremet, M. A.

    2015-03-01

    A numerical analysis of spatial laminar regimes of natural convection in an enclosure is conducted in the presence of a uniform magnetic field. The mathematical model formulated in dimensionless natural variables "velocity-pressure-temperature" has been implemented numerically by the method of control volume. The influence of the Rayleigh number (103 ≤ Ra ≤ 105) and the Hartmann number (0 ≤ Ha ≤ 100), the orientation of the magnetic induction vector (0 ≤ φ ≤ π/2) as well as of the geometric parameter (0.2 ≤ A ≤ 5), which reflects the enclosure relative length, on the velocity and temperature distributions as well as the average Nusselt number on a typical isothermal boundary has been studied in detail. A possibility of describing the integral heat exchange in the spatial object under consideration on the basis of the two-dimensional model has been established.

  5. Canonical Statistical Model for Maximum Expected Immission of Wire Conductor in an Aperture Enclosure

    Science.gov (United States)

    Bremner, Paul G.; Vazquez, Gabriel; Christiano, Daniel J.; Trout, Dawn H.

    2016-01-01

    Prediction of the maximum expected electromagnetic pick-up of conductors inside a realistic shielding enclosure is an important canonical problem for system-level EMC design of space craft, launch vehicles, aircraft and automobiles. This paper introduces a simple statistical power balance model for prediction of the maximum expected current in a wire conductor inside an aperture enclosure. It calculates both the statistical mean and variance of the immission from the physical design parameters of the problem. Familiar probability density functions can then be used to predict the maximum expected immission for deign purposes. The statistical power balance model requires minimal EMC design information and solves orders of magnitude faster than existing numerical models, making it ultimately viable for scaled-up, full system-level modeling. Both experimental test results and full wave simulation results are used to validate the foundational model.

  6. Influence of a strong magnetic field on paramagnetic fluid's flow in cubical enclosure

    Science.gov (United States)

    Kraszewska, A.; Pyrda, L.; Donizak, J.

    2016-10-01

    The fluid behaviour in thermo-magnetic convection of paramagnetic fluid in a strong magnetic field was studied. The fluid was 50% volume aqueous solution of glycerol with an addition of gadolinium nitrate hexahydrate (Gd(NO3)3-6H2O). Experimental enclosure - a vessel with aspect ratio (AR=height/width) equal to 1.0 - was heated from the bottom, and cooled from the top. Temperature difference between top and bottom walls was kept constant at ΔT = 5 and 11 [°C]. The magnetic induction was increased stepwise from 1 to 10 [T] and thermocouples placed inside the enclosures measured temperature changes of the fluid. On the basis of temperature measurements, analysis of the fluid flow was performed.

  7. RELAP5-3D multidimensional heat conduction enclosure model for RBMK reactor application

    Energy Technology Data Exchange (ETDEWEB)

    Paik, S.

    1999-10-01

    A heat conduction enclosure model is conceived and implemented by RELAP5-3D between heat structures. The suggested model uses a lumped parameter model that is generally applicable to multidimensional calculational domain. This new model is applied to calculation of RBMK reactor core graphite blocks and is compared to the commercially available Fluid Dynamics Analysis Package (FIDAP) finite element code. Reasonably good agreement between the results of RELAP5-3D and FIDAP is obtained. The new heat conduction enclosure model gives RELAP5-3D a general multidimensional heat conduction capability. It also provides new routes for temperature cooloff of the RBMK graphite blocks from the ruptured channel to the surrounding ones. This ability to predict graphite temperature cooloff is very important during accidents or for transient simulation, especially concerning long-term coolability of the RBMK reactor core.

  8. A Bayesian Approach to the Orientations of Central Alentejo Megalithic Enclosures

    Science.gov (United States)

    Pimenta, Fernando; Tirapicos, Luís; Smith, Andrew

    2009-12-01

    In this work we have conducted a study on the orientations in the landscape of twelve megalithic enclosures in the Alentejo region of southern Portugal. Some of these sites date back to the sixth or fifth millennium B.C. and are among the oldest stone enclosures in Europe. The results of the survey show a pattern toward eastern rising orientations. We used dedicated GIS software from one of the authors to produce horizon profiles and applied a statistical Bayesian approach in an attempt to check how the data would fit to different models. In particular, we tested our results for a possible ritual interest in the Autumn or Harvest Full Moon and discuss previous studies by Michael Hoskin and colleges on the orientations of seven stone dolmens of this area that have shown the existence of a possible custom for an orientation toward the sunrise.

  9. Radiative and free-convective heat transfer from a finite horizontal plate inside an enclosure

    Science.gov (United States)

    Hrycak, Peter; Sandman, D. J.

    1986-01-01

    An experimental and analytical investigation of heat transfer from a horizontal, thin, square plate inside of an enclosure was carried out. Experimental results were obtained from both the upward-facing and the downward-facing sides of the heated plate. Starting with the integrated momentum and energy equations, approximate solutions were obtained for heat transfer in the laminar and the turbulent regime that correlate well with experimental data. Radiative heat transfer correction was given special attention. Effects of the enclosure-related recirculation of the test fluid, as well as effects of simultaneous heat transfer on both sides of the plate, caused an early transition, and indicated a high level of internal turbulence.

  10. GMT site, enclosure, and facilities design and development overview and update

    Science.gov (United States)

    Teran, Jose; Burgett, William S.; Grigel, Eric; Bigelow, Bruce C.; Donoso, Eduardo; Figueroa, Francisco

    2016-07-01

    The Giant Magellan Telescope (GMT) will have a 25.4-meter diameter effective aperture, and is one the three currently planned next generation extremely large telescopes (ELTs). The GMT will be located at the summit of Cerro Campanas at the Las Campanas Observatory (LCO) in Chile, one the world's best observing sites. This paper provides an overview of the site master plan comprising site infrastructure, enclosure, and facilities, and outlines the analysis of alternative trade studies that will lead to the final design. Also presented is an update of the site infrastructure development and preconstruction activities currently underway that will be completed prior to the beginning of enclosure construction near the end of 2016.

  11. Health and Safety Research Division manual for the x-ray facility in Building 2008

    Energy Technology Data Exchange (ETDEWEB)

    Stansbury, P. S.

    1977-11-01

    The facility in the east end of Building 2008, ORNL, consists of an x-ray machine and a shielded enclosure. The x-ray machine is of the constant potential type and can be operated continuously at generating potentials up to 125 kVcp with tube currents ranging from 0.1 ..mu..A to 10 mA. Both the generating potential and the tube current are highly regulated and stabilized. The machine is installed and operated within a large shielded enclosure. In addition to the x-ray machine and its ancillary equipment, the shielded enclosure contains many of the features of a general chemistry and physics laboratory including work benches, sinks, storage space, and electrical and gas service. This manual contains instructions for the safe operation of the x-ray machine.

  12. Blooms of the dinoflagellate Glenodinium sanguineum obtained during enclosure experiments in Lake Tovel (N. Italy

    Directory of Open Access Journals (Sweden)

    Monica TOLOTTI

    2003-02-01

    Full Text Available Freshwater red tides due to dinoflagellates are less common than their marine analogues, which are usually a serious problem and can even be toxic. This was not the case for Lake Tovel in the Adamello-Brenta Natural Park (Southern Alps, Italy, where the dinoflagellate Glenodinium sanguineum Marchesoni accumulated carotenoids (astaxanthin-like compound and caused a spectacular and regular "summer reddening", which suddenly ceased in 1964. Today Lake Tovel is a temperate, meromictic (with dimictic mixolimnion, oligotrophic mountain lake, characterised by marked water level fluctuations. G. sanguineum is still present in the lake, although with markedly lower densities in comparison to the pre-1965 period. Enclosure studies were carried out to identify the main factors regulating the blooms. In 1998, by means of phosphorus enrichments, it was possible to obtain a marked increase in numbers of G. sanguineum. Phosphorus additions in similar enclosures in 1999, when weather conditions during the summer were not optimal (mostly cloudy with frequent rainfalls, did not have the same effect, since species known to thrive in spring or under icecover developed. In summer 2000, by attenuating light in one of the enclosures, it was shown that irradiance conditions strongly interacted with phosphorus availability in determining the species that dominated the phytoplankton. In summer 2001, G. sanguineum increased again in the enclosure enriched with phosphorus. Nitrogen was observed to become a limiting factor only in conditions forced by phosphorus additions. From the first four years of in situ experiments, we concluded that phosphorus and light conditions were among the key factors controlling the proliferation and the dominance of G. sanguineum.

  13. 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.

  14. 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.

  15. Thermosolutal bifurcation phenomena in porous enclosures subject to vertical temperature and concentration gradients

    Science.gov (United States)

    Mamou, M.; Vasseur, P.

    1999-09-01

    The Darcy model with the Boussinesq approximations is used to study double-diffusive instability in a horizontal rectangular porous enclosure subject to two sources of buoyancy. The two vertical walls of the cavity are impermeable and adiabatic while Dirichlet or Neumann boundary conditions on temperature and solute are imposed on the horizontal walls. The onset and development of convection are first investigated using the linear and nonlinear perturbation theories. Depending on the governing parameters of the problem, four different regimes are found to exist, namely the stable diffusive, the subcritical convective, the oscillatory and the augmenting direct regimes. The governing parameters are the thermal Rayleigh number, RT, buoyancy ratio, N, Lewis number, Le, normalized porosity of the porous medium, [epsilon], aspect ratio of the enclosure, A, and the thermal and solutal boundary condition type, [kappa], applied on the horizontal walls. On the basis of the nonlinear perturbation theory and the parallel flow approximation (for slender or shallow enclosures), analytical solutions are derived to predict the flow behaviour. A finite element numerical method is introduced to solve the full governing equations. The results indicate that steady convection can arise at Rayleigh numbers below the supercritical value, indicating the development of subcritical flows. At the vicinity of the threshold of supercritical convection the nonlinear perturbation theory and the parallel flow approximation results are found to agree well with the numerical solution. In the overstable regime, the existence of multiple solutions, for a given set of the governing parameters, is demonstrated. Also, numerical results indicate the possible occurrence of travelling waves in an infinite horizontal enclosure.

  16. Seed trait and rodent species determine seed dispersal and predation: evidences from semi-natural enclosures

    OpenAIRE

    Yi X; Wang Z.; Liu C; Liu G.

    2015-01-01

    Seed traits affect seed dispersal by animals. However, the combined role of seeds and dispersers in determining seed dispersal is not well explored. We attempted to test how seed traits and predators determine seed dispersal and predation interaction in a rodent-mediated seed dispersal system. Semi-natural enclosure experiments were conducted to investigate seed dispersal and predation of five sympatric tree species with different seed traits, Juglans mandshurica, Quercus mongolica, Pinus kor...

  17. Double-diffusive natural convection in an enclosure filled with nanofluid using ISPH method

    OpenAIRE

    Abdelraheem M Aly; Zehba A.S. Raizah

    2016-01-01

    The double-diffusive natural convection in an enclosure filled with nanofluid is studied using ISPH method. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. In addition the thermal energy equations include regular diffusion and cross-diffusion terms. In ISPH algorithm, a semi implicit velocity correction procedure is utilized and the pressure is implicitly evaluated by solving pressure Poisson equation. The results are presented with flow config...

  18. Construction and Validation of a Systematic Ethogram of Macaca fascicularis in a Free Enclosure

    OpenAIRE

    Fan Xu; Liang Xie; Xin Li; Qi Li; Tao Wang; Yongjia Ji; Fei Kong; Qunlin Zhan; Ke Cheng; Liang Fang; Peng Xie

    2012-01-01

    Behavioral studies in non-human primates have become ideal models for further investigations into advanced cognitive function in humans. To date, there is no systematic ethogram of the cynomolgus monkey (Macaca fascicularis) in a free enclosure. In a field observation of 6012 subjects, 107 distinct behaviors of M. fascicularis were preliminarily described. 83 of these behaviors were then independently validated through a randomized cohort and classified into 12 behavioral categories. 53 of th...

  19. Possible astronomical references in the project of the megalithic enclosures of Gobekli Tepe

    CERN Document Server

    Magli, Giulio

    2013-01-01

    The megalithic enclosures of Gobekli Tepe (Urfa, Turkey) are the most ancient sacred structures of stone known so far, dating back to the 10 millennium BC. The possible presence of astronomical targets for these structures is analysed, and it turns out that they may have been oriented, or even originally constructed, to celebrate and successively follow the appearance of a new, extremely brilliant star in the southern skies: Sirius.

  20. Active control of interior noise within an irregular enclosure under the cooperation of point force and incident wave

    Institute of Scientific and Technical Information of China (English)

    GENG Houcai; RAO Zhushi; HAN Zushun; ZHANG Hualiang

    2002-01-01

    A new modeling method is developed for the active control of interior noise within an irregular three-dimensional cavity under the cooperation of point force and incident wave. The validity of this method is verified by a regular cuboid enclosure. With global and local per-formance functions, good results are obtained in the active control of noise within the irregular enclosure according to numerical investigations.

  1. 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.

  2. 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.

  3. Determination of 4-nonylphenol concentrations in sediment from a littoral enclosure study

    Energy Technology Data Exchange (ETDEWEB)

    Sheedy, B.R. [Integrated Lab. Systems, Duluth, MN (United States); Heinis, L.J. [Univ. of Wisconsin, Superior, WI (United States); Knuth, M.L.; Ankley, G.T. [Environmental Protection Agency, Duluth, MN (United States). Environmental Research Lab.

    1994-12-31

    During the summer of 1993, a small pond, divided into 18 littoral enclosures was dosed for 21 days with the industrial surfactant metabolite, 4-nonylphenol (NP). A team of biologists and chemists monitored the biological and chemical parameters in each littoral enclosure during the dosing period and for several months thereafter. The water column NP concentrations (nominal 0, 3, 30, 1 00 and 300 ppb) remained relatively constant throughout the dosing period and decreased dramatically during the post-dose phase Natural sediment concentrations, determined during the post-dose phase, in most cases remained high, especially at the 300 ppb level. Artificial containers of sediment placed in several enclosures had somewhat lesser concentrations than the natural sediment. Over the six week sampling period (post-dose), the natural sediment concentrations dropped off, but were still significant at 63 days post-dose. This NP disappearance was small in comparison to the disappearance of NP from the water column. Sediment interstitial NP concentrations were not detected. Concentrations of NP in the sediment after winter will be determined and discussed.

  4. Extraction of enclosure culture area from SPOT-5 image based on texture feature

    Science.gov (United States)

    Tang, Wei; Zhao, Shuhe; Ma, Ronghua; Wang, Chunhong; Zhang, Shouxuan; Li, Xinliang

    2007-06-01

    The east Taihu lake region is characterized by high-density and large areas of enclosure culture area which tend to cause eutrophication of the lake and worsen the quality of its water. This paper takes an area (380×380) of the east Taihu Lake from image as an example and discusses the extraction method of combing texture feature of high resolution image with spectrum information. Firstly, we choose the best combination bands of 1, 3, 4 according to the principles of the maximal entropy combination and OIF index. After applying algorithm of different bands and principal component analysis (PCA) transformation, we realize dimensional reduction and data compression. Subsequently, textures of the first principal component image are analyzed using Gray Level Co-occurrence Matrices (GLCM) getting statistic Eigen values of contrast, entropy and mean. The mean Eigen value is fixed as an optimal index and a appropriate conditional thresholds of extraction are determined. Finally, decision trees are established realizing the extraction of enclosure culture area. Combining the spectrum information with the spatial texture feature, we obtain a satisfied extracted result and provide a technical reference for a wide-spread survey of the enclosure culture area.

  5. Active Noise Control in a Three Dimensional Enclosure Using Multichannel Fuzzy LMS Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Hyun Do [Dankook University (Korea, Republic of); Kim, Kyun Tae [Haitai Electronics R and D Cemter (Korea, Republic of)

    1998-05-01

    In this paper, active noise control(ANC) in an enclosure using multi-channel fuzzy LMS(MCFLMS) algorithm is considered. A new model for a secondary path transfer function, which has common acoustical poles that correspond to resonance properties of an enclosure, is used. Since this model requires far fewer variable parameters to represent secondary path transfer functions than those of conventional all-zero or pole and zero models, it reduces the computational complexity for an active noise control system. A MCFLMS algorithm, where the convergence coefficients of a multi-channel LMS(MCLMS) algorithm is derived by a fuzzy inference engine, is proposed. This algorithm shows better convergence than the existing MCLMS algorithms and it does not require pre-adjustment of convergence parameters, so it could be easily applied to practical ANC systems. Computer simulations and experiments were performed to show the effectiveness of the proposed algorithm in experimental enclosure. The proposed method shows better results in both computer simulations and experiments. (author). 14 refs., 10 figs., 2 tabs.

  6. Effect of Rotation on Natural Convection in Differentially Heated Rotating Enclosure by Numerical Simulation

    Directory of Open Access Journals (Sweden)

    M. Narendra Kumar

    2016-01-01

    Full Text Available Natural convection heat transfer in a two dimensional unsteady rotating differentially heated enclosure is studied numerically in this paper. The enclosure is filled with air and executes a steady counterclockwise rotation about the centre of the enclosure. A finite volume code on a staggered grid arrangement with TDMA algorithm is developed and employed to solve the governing equations subject to Boussinesq approximation. The numerical investigation is carried out for fixed Prandtl number equal to 0.71, Rayleigh number equal to1.1×〖10〗^5 while Taylors number vary from5.2×〖10〗^4 to 3.3×〖10〗^5and Rotational Rayleigh number from 4.9×〖10〗^2 to 3.1×〖10〗^3.Results reveal that there are considerable change in heat transfer rates beyond 15 rpm. The effect of rotation on the Nusselt number for a given Rayleigh number is shown in the present work which is not normally indicated and discussed in the available literature

  7. 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.

  8. Optimization of natural convection heat transfer of Newtonian nanofluids in a cylindrical enclosure

    Institute of Scientific and Technical Information of China (English)

    Hamid Moradi; Bahamin Bazooyar; Ahmad Moheb; Seyed Gholamreza Etemad

    2015-01-01

    This study characterizes and optimizes natural convection heat transfer of two Newtonian Al2O3 and TiO2/water nanofluids in a cylindrical enclosure. Nusselt number (Nu) of nanofluids in relation to Rayleigh number (Ra) for different concentrations of nanofluids is investigated at different configurations and orientations of the enclosure. Results show that adding nanoparticles to water has a negligible or even adverse influence upon natural convec-tion heat transfer of water:only a slight increase in natural convection heat transfer of Al2O3/water is observed, while natural convection heat transfer for TiO2/water nanofluid is inferior to that for the base fluid. Results also reveal that at low Ra, the likelihood of enhancement in natural convection heat transfer is more than at high Ra:at low Ra, inclination angle, aspect ratio of the enclosure and nanoparticle concentration influence natural convec-tion heat transfer more pronouncedly than that in high Ra.

  9. Non—Darcian and Anisotropic Effects on Natural Convection in Horizontal Porous Media Enclosure

    Institute of Scientific and Technical Information of China (English)

    ZhangJingzhou; SunRenqia

    1996-01-01

    Natural convection heat transfer in a horizontal enclosure filled with anisotropic porous media,being isothermally heated at bettom and cooled at top while the vertical walls being adiabatic,is numerically studied by applying the Brinkman model-a modified form of Darcy model giving consideratioin to the viscous effect.The results show that:(1)a larger permeability ratio(K*) causes a lower flow intensity in the enclosure and a smaller Nusselt number,all Nusselt numbers approach unity in the limit of K*→∞;a larger thermal conductivity ratio(λ*) causes a stranger distortion of isotherms in the enclosure and a higher flow velocity near the walls,all the Nusselt numbers approach unity in the limit of λ*-→0,the permeability and thermal conductivity ratios generally have opposing effects on the Nusselt number.(2) an increasing Darcy number decreases the flow intensity and heat tansfer rates,which is more significant at a lower permeability ratio.In particular,with K*≤0.25,the Nusselt number for Da=10-3 would differ from that of Darcy flow up to an amount of 30%,an analysis neglecting the non-Darican effect will inevitably be of considerable error.

  10. Building Materials

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Building Materials Sub-council of CCPIT is the other sub-council in construction field. CCPIT Building Materials Sub-council (CCPITBM), as well as CCOIC Build-ing Materials Chamber of Commerce, is au-thorized by CCPIT and state administration of building materials industry in 1992. CCPITBM is a sub-organization of CCPIT and CCOIC.

  11. Transient Sound Intensity Measurements for Evaluating the Spatial Information of Sound Fields in Reverberant Enclosures.

    Science.gov (United States)

    Abdov, Adel Abdel-Moneim

    Over the last twenty years, new subjectively relevant objective room-acoustic indicators for evaluating the acoustical quality of an enclosure have been introduced. While these indicators give new insight into the acoustical "Goodness" of a listener position, in order to design halls, assess or to correct an acoustical defect in an existing enclosure, there is a need to understand to what extent they are influenced by the physical design features of the enclosure. To meet such a need, information about the directional characteristics of sound is required. The spatial distribution of sound energy is usually not considered due to lack of an efficient, accurate and easy to perform measurement method. The main objectives of the present study are, first; to review known and speculative room-acoustic indicators for use in assessing reverberant spaces such as concert halls, opera houses, multi-purpose halls and churches. Second, to introduce an easy to perform measurement method for directional sensing in sound fields. Third, to develop a simple and inexpensive PC-based instrument primarily for the measurement of sound fields directional characteristics as well as contemporary room-acoustic indicators. Fourth, to propose new room-acoustic indicators which have relevance to directional information. This study introduces a three-dimensional sound intensity measurement technique for obtaining spatial information of sound fields in an enclosure. The technique has been validated and its accuracy investigated. The method gives results that provide valuable information regarding the directional behaviour of sound in enclosures. Subsequently both the system and the measurement method were applied to known spaces as example applications in order to assess sound quality, to detect the effect of the surrounding interior features of the space, and to assess potential diagnostic capability with respect to interior physical changes. The study has validated the measurement procedure as

  12. Numerical modeling of mixing in large stably stratified enclosures using TRACMIX++

    Science.gov (United States)

    Christensen, Jakob

    This PhD dissertation focuses on the numerical modeling of stably stratified large enclosures. In stably stratified volumes, the distribution of temperature, species concentration etc become essentially 1-D throughout most of the enclosure. When the fluid in an enclosure is stratified, wall boundary buoyant jets, forced buoyant jets (injection of fluid) and natural convection plumes become the primary sources of mixing. The time constants for the buoyant jets may be considered as much smaller than the time constant for the mixing of the stratified ambient fluid, provided the combined volume occupied by the buoyant jets is small compared to the volume of the enclosure. Therefore, fluid transport by the buoyant jets may be considered as occurring instantaneously. For this reason this work focuses on deriving a numerical method which is able to solve the 1-D vertical fluid conservation equations, as given in Peterson (1994). Starting with the Eulerian fluid conservation equations given in Peterson (1994), a set of Lagrangian fluid conservation equations were derived. Combining the Lagrangian approach with operator splitting such that the convective step and the diffusive step is separated renders a very efficient, accurate, and stable numerical method as it is shown in this text. Since the stratified flow field frequently exhibits very strong gradients or so-called fronts, the generation of these fronts has to be accurately detected and tracked by the numerical method. Flow in stably stratified large enclosure has typically been modeled in the past using 1- or 2-zone models. The present model is new in that it belongs to the K-zone models where the number of zones is arbitrarily large and depends on the complexity of the solution and the accuracy requirement set by the user. Because fronts are present in the flow field, a Lagrangian type numerical method is used. A Lagrangian method facilitates front tracking and prevents numerical diffusion from altering the shape of

  13. Study of the Hygric Behaviour and Moisture Buffering Performance of a Hemp–Starch Composite Panel for Buildings

    Directory of Open Access Journals (Sweden)

    Chadi Maalouf

    2014-11-01

    Full Text Available This paper presents the results of a laboratory investigation into the hygric properties and moisture buffering performance of hemp-starch composite panels designed for building applications. Composite panels were produced by bonding hemp shiv with wheat starch as a binder. Two types of hemp shiv were tested: chemically processed shiv with enhanced adhesion between fibers and starch matrix, and non-treated shiv. The panels were then characterised in terms of their hygroscopic properties (sorption curve and vapour diffusion resistance factor and their moisture buffering performance (moisture buffering value, MBV. The determination of theoretical MBV was based on the effusivity of the material, which is obtained from its basic hygroscopic characterisation. The results show that both panels are excellent hydric regulators that can be used to improve indoor hygrothermal comfort by buffering indoor relative humidity variations.

  14. Bio-aggregates based building materials state-of-the-art report of the RILEM Technical Committee 236-BBM

    CERN Document Server

    Collet, Florence

    2017-01-01

    The work of the RILEM Technical Committee (TC -236 BBM) was dedicated to the study of construction materials made from plant particles. It considered the question whether building materials containing as main raw material recyclable and easily available plant particles are renewable. This book includes a state-of-the-art report and an appendix. The state-of-the-art report relates to the description of vegetal aggregates. Then, hygrothermal properties, fire resistance, durability and finally the impact of the variability of the method of production of bio-based concrete are assessed. The appendix is a TC report which presents the experience of a working group. The goal was to define testing methods for the measurement of water absorption, bulk density, particle size distribution, and thermal conductivity of bio aggregates. The work is based on a first round robin test of the TC-BBM where the protocols in use by the different laboratories (labs) are compared. .

  15. Invention, design and performance of coconut agrowaste fiberboards for ecologically efficacious buildings

    Science.gov (United States)

    Lokko, Mae-ling Jovenes

    As global quantities of waste by-products from food production as well as the range of their applications increase, researchers are realizing critical opportunities to transform the burden of underutilized wastes into ecological profits. Within the tropical hot-humid region, where half the world's current and projected future population growth is concentrated, there is a dire demand for building materials to meet ambitious development schemes and rising housing deficits. However, the building sector has largely overlooked the potential of local agricultural wastes to serve as alternatives to energy-intensive, imported building technologies. Industrial ecologists have recently investigated the use of agrowaste biocomposites to replace conventional wood products that use harmful urea-formaldehyde, phenolic and isocyanate resins. Furthermore, developments in the performance of building material systems with respect to cost, energy, air quality management and construction innovation have evolved metrics about what constitutes material 'upcycling' within building life cycle. While these developments have largely been focused on technical and cost performance, much less attention has been paid to addressing deeply-seated social and cultural barriers to adoption that have sedimented over decades of importation. This dissertation evaluates the development coconut agricultural building material systems in four phases: (i) non-toxic, low-energy production of medium-high density boards (500-1200 kg/m3) from coconut fibers and emerging biobinders; (ii) characterization and evaluation of coconut agricultural building materials hygrothermal performance (iii) scaled-up design development of coconut modular building material systems and (iv) development of a value translation framework for the bottom-up distribution of value to stakeholders within the upcycling framework. This integrated design methodological approach is significant to develop ecological thinking around agrowaste

  16. METHOD FOR DECREASE OF STANDARD HEAT LOSSES IN RESIDENTIAL BUILDINGS

    Directory of Open Access Journals (Sweden)

    A. E. Piir

    2017-01-01

    Full Text Available A simplified method for calculation of standard coefficient for heat transfer in a residential building has been developed in the paper. Investigations have been carried out with the purpose to determine influence of building size, level of thermal insulation in external enclosures and share of heat regeneration in ventilation system on total heat losses. The paper considers buildings of a simple geometrical form (“matchbox” with number of floors 1, 2, 4, 8, 16 and living area from 100 up to 25600 m2 at the level of thermal resistance of walls 1; 3 and 5 m2 ⋅°C/W and share of heat regeneration in ventilation air stream of 0; 0.5 and 0.66. The investigation results have shown that while increasing building size then there is a sudden transformation of dimensions and structure in external enclosures: share of overlapping area is reduced by 3-fold and share of wall area is increased by 2-fold. Surface area of building external envelope is reduced by 6-fold in comparison with its heated area. An average coefficient of building heat transfer assigned to heated area is decreased by 3-fold. It has been shown that the most efficient methods for further decrease of standard heat losses for residential buildings are the following: heat recovery in the ventilation system: it is deeper if heat protection rate is higher and climate of a building construction zone is colder; enlargement of building size through decrease of their number; limit-exceeding increase in heat protection of small apartment buildings and cottages; cubic form of 2–3-floor buildings for Far North.

  17. An Analysis of the Indoor Air Quality and Mould Growth in a Multi-zone Building

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Ashfaque Ahmed, E-mail: a.chowdhury@cqu.edu.au; Rasul, M. G.; Khan, M. M. K. [Central Queensland University, College of Engineering and Built Environment, Faculty of Sciences, Engineering and Health (Australia)

    2009-12-15

    The effects of poor indoor air quality and mould growth in working environment are major problems in built environment, and there is a need to look for improvement of the health, comfort and productivity of the building occupants. Airborne mould sampling studies were conducted in a reference building located in Rockhampton, Central Queensland, Australia. Both indoor culturable and mould spore levels were observed. It was found through the indoor-outdoor ratios of the species that indoor concentrations are mostly related to the outdoor mould levels. The moulds differ in their relative humidity and temperature requirements to support surface growth. Indoor humidity has a significant effect on occupants comfort, perceived air quality, occupants' health, building durability, emissions and energy efficiency. Practical hygrothermal simulation models are employed to analyse the combined heat and moisture behaviour within the built environment. A review of the current modelling options available to predict building performance based on energy and mass transport simulation is presented, and then a case study is presented with the assessment of indoor built environment to avoid mould problem.

  18. 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.

  19. Analytical techniques for sesquiterpene emission rate studies in vegetation enclosure experiments

    Science.gov (United States)

    Helmig, Detlev; Bocquet, Florence; Pollmann, Jan; Revermann, Tobias

    Sesquiterpene (SQT) compounds (C 15H 24) and their oxygenated alcohol and ketone derivatives are biogenic volatile organic compounds that have been identified in emissions from vegetation. SQT emission rates and landscape flux estimates are highly uncertain. Reliable ambient flux measurements have not been possible because of low-ambient concentrations, rapid atmospheric reactions (prohibiting ambient tower flux measurements), and analytical challenges and uncertainties that stem from the low volatility of SQT. Standards from an in situ capillary diffusion system with 18 SQT compounds and four other organic compounds (geranylacetone, 1,3,5-tri-isopropylbenzene, diphenylmethane, nonylbenzene) were used to thoroughly investigate experimental procedures for SQT emission rate studies by vegetation enclosure techniques. Recovery rates in tubing materials, sampling bags, leaf cuvettes, on six solid adsorbent materials (Tenax TA, Tenax GR, Carbotrap, Carbotrap C, Unibeads, Glass Beads) for gas chromatography analysis, and gas chromatography retention indices and mass spectral fragmentation patterns were determined. SQT compounds were found to exhibit a high degree of stickiness to all materials tested. However, the non-oxygenated SQT can be recovered in enclosure experiments for quantitative emission rate determination after careful consideration of the analytical conditions. It is utmost important to allow sufficient purging and equilibration times for all materials in contact with the sample air. In contrast oxygenated SQT were irreversibly lost in enclosure experiments which made their quantitative measurement prohibitive. Results for the other organic compounds were similar and indicate that these data mostly stem from the volatility of these compounds. Consequently, the findings of this study provide guidelines for the analysis of a wide range of volatile organic compounds in the ˜C13-C17 volatility range.

  20. Eutrophication and algal blooms in channel type reservoirs: A novel enclosure experiment by changing light intensity

    Institute of Scientific and Technical Information of China (English)

    Chengjin Cao; Binghui Zheng; Zhenlou Chen; Minsheng Huang; Jialei Zhang

    2011-01-01

    To explore eutrophication and algal bloom mechanisms in channel type reservoirs,a novel enclosure experiment was conducted by changing light intensity (LI) in the Daning River of the Three Gorges Reservoir (TGR).Square enclosures (side 5.0 m) were covered on the surface with shading materials of different thickness,and with their bases open to the river.Changes and characteristics of the main eutrophication factors under the same water quality and hydrodynamic conditions but different LI were evaluated.All experimental water samples were neutral and alkalescent,with high nitrogen and phosphate concentrations,low potassium permanganate index,stable water quality,and different LI.At the same water depth,LI decreased with increasing shade material,while dissolved oxygen and water temperature were both stable.The growth peak of phytoplankton was with light of 345-4390 lux underwater or 558-7450lux above the water surface,and water temperature of 25.6-26.5℃.Algae were observed in all water samples,accounting for 6 phylum and 57 species,with algal density changing frequently.The results showed that significantly strong or weak light was unfavorable for phytoplankton growth and the function together with suitable temperature and LI and ample sunshine encouraged algal blooms under the same water quality and hydrodynamic conditions.Correlation analysis indicated that algae reduced gradually lengthwise along water depth in the same enclosure while pH became high.The power exponent relationship between chlorophyll a (Chl-a) and LI was found by curve fitting,that is Chi-a =K(LI)n.

  1. 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.

  2. Effect of a vibrating side wall on convective heat transfer in an enclosure with varying bottom wall temperature distribution

    Science.gov (United States)

    Raheimpour Angeneh, Saeid; Aktas, Murat K.

    This study mainly focuses on the thermal convection in a rectangular enclosure in the presence of streaming motion while temperature profile of bottom wall is sinusoidal. The effect of wall displacement amplitude and the bottom wall temperature profile on convective heat transfer in the enclosure are determined with the help of a parametric study. By vibrating side wall of the enclosure, oscillating flow is actuated. The top wall of the enclosure is kept at initial temperature and isothermal while the side walls are adiabatic. In order to predict the oscillatory and time averaged mean flow fields, fully compressible form of the Navier - Stokes equations are considered. Simulation of the convective transport in the enclosure is obtained by a control-volume method based, explicit computational scheme is used. The aim of this study is to provide interpretation of the flow and thermal transport physics. The influence of nonzero mean vibrational flow on the thermal convection from a surface with sinusoidal temperature distribution has never been investigated before. Conclusions may lead up to design of new heat removal applications.

  3. Physicochemical Process, Crustacean, and Microcystis Biomass Changes In Situ Enclosure after Introduction of Silver Carp at Meiliang Bay, Lake Taihu

    Directory of Open Access Journals (Sweden)

    Chengjie Yin

    2017-01-01

    Full Text Available In order to control cyanobacteria blooms with silver carp in Lake Taihu, an in situ experiment was carried out by stocking silver carp at a biomass of 35, 70, and 150 g m-3 and no carp control in waterproof enclosures. Physicochemical water parameters and biomass of plankton were measured in enclosures to evaluate the suitable stocking density of silver carp for relieving internal nutrients and constraining cyanobacteria growth in Lake Taihu. It is found that the 35 g m-3 silver carp group and 70 g m-3 silver carp group presented lower total phosphorus, lower chlorophyll-a, and higher water transparency. Increased nitrogen to phosphorus ratio, which indicated the result of algae decline in fish presence enclosures, was attributed to decline of phosphorus. Phosphorus decline also exerted limitation on reestablish of cyanobacteria bloom. Crustacean zooplankton biomass and Microcystis biomass decreased significantly in fish presence enclosures. Silver carp could be more effective to regulate algae bloom in enclosures with dense cyanobacteria. Therefore, nonclassic manipulation is supposed to be appropriate method to get rid of cyanobacteria blooms in Lake Taihu by stocking 35 to 70 g m-3 silver carp in application.

  4. 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.

  5. 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

    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...

  6. 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.

  7. 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.

  8. Melting of nanoparticles-enhanced phase change material (NEPCM) in vertical semicircle enclosure: numerical study

    Energy Technology Data Exchange (ETDEWEB)

    Jourabian, Mahmoud [University of Trieste, Piazzale (Italy); Farhadi, Mousa [Babol Noshirvani University of Technology, Shariati Avenue (Iran, Islamic Republic of)

    2015-09-15

    Convection melting of ice as a Phase change material (PCM) dispersed with Cu nanoparticles, which is encapsulated in a semicircle enclosure is studied numerically. The enthalpy-based Lattice Boltzmann method (LBM) combined with a Double distribution function (DDF) model is used to solve the convection-diffusion equation. The increase in solid concentration of nanoparticles results in the enhancement of thermal conductivity of PCM and the decrease in the latent heat of fusion. By enhancing solid concentration of nanoparticles, the viscosity of nanofluid increases and convective heat transfer dwindles. For all Rayleigh numbers investigated in this study, the insertion of nanoparticles in PCM has no effect on the average Nusselt number.

  9. Evaluation of Crawlspace Retrofits in Multifamily Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, Armin [Building Science Corporation, Somerville, MA (United States)

    2014-09-01

    In 2011 and early 2012, Building Science Corporation (BSC) collaborated with Innova Services Corporation on a multifamily community unvented crawlspace retrofit project at Oakwood Gardens in Lansdale, Pennsylvania. BSC provided design consulting services and pre- and post-retrofit evaluation, testing, and data monitoring. The existing condition was a vented crawlspace with an uninsulated floor between the crawlspace and the dwelling units above. The crawlspace was therefore a critically weak link in the building enclosure and was ripe for improvement. Saving energy was the primary interest and goal, but the greatest challenge in this unvented crawlspace retrofit project was working through a crawlspace bulk water intrusion problem caused by inadequate site drainage, window well drainage, foundation wall drainage, and a rising water table during rainy periods.

  10. Magneto-Hydrodynamic Flow in a Two-Dimensional Inclined Rectangular Enclosure Heated and Cooled on Adjacent Walls

    Directory of Open Access Journals (Sweden)

    M.N Kherief

    2016-01-01

    Full Text Available Steady, laminar, natural-convection flow in the presence of a magnetic field in an inclined rectangular enclosure heated from one side and cooled from the adjacent side was considered. The governing equations were solved numerically for the stream function, vorticity and temperature using the finite-volume method for various Grashof and Hartman numbers and inclination angles and magnetic field directions. The results show that the orientation and the strength and direction of the magnetic field have significant effects on the flow and temperature fields. Counterclockwise inclination induces the formation of multiple eddies inside the enclosure significantly affecting the temperature field. Circulation inside the enclosure and therefore the convection become stronger as the Grashof number increases while the magnetic field suppresses the convective flow and the heat transfer rate.

  11. MHD natural convection with Joule and viscous heating effects in iso-flux porous medium-filled enclosures

    Institute of Scientific and Technical Information of China (English)

    Y.M.AL-BADAWI; H.M.DUWAIRI

    2010-01-01

    In this study,the magnetohydrodynamics(MHD)natural convection heat transfer with Joule and viscous heating effects inside an iso-flux porous medium-filled inclined rectangular enclosure is studied numerically.An iso-heat flux is applied for heating and cooling the two opposing walls of the enclosure while the other walls are adiabatic.The Forchheimer extension of Darcy-Oberbeck-Boussinesq and energy equations is transformed into a dimensionless form using a set of suitable variables instead of a finite difference scheme.The governing parameters axe the magnetic influence number,the modified Rayleigh number,the inclination angle,and the aspect ratio of the enclosure.The results show that viscous and Joule heating effects decrease heat transfer rates.

  12. Focusing Waves at Arbitrary Locations in a Ray-Chaotic Enclosure Using Time-Reversed Synthetic Sonas

    CERN Document Server

    Xiao, Bo; Ott, Edward; Anlage, Steven M

    2014-01-01

    Time reversal mirrors have been widely used to achieve wave focusing in acoustics and electromagnetics. A typical time reversal experiment requires that a transmitter be initially present at the target focusing point, which limits the application of this technique. In this letter, we propose a method to focus waves at an arbitary location inside a complex enclosure using a numerically calculated wave signal. We use a semi-classical ray algorithm to calculate the signal that would be received at a transceiver port resulting from the injection of a short pulse at the desired target location. The quaility of the reconstruction is quantified in three different ways and the values of these metrics can be predicted by the statistics of the scattering-parameter $|S_{21}|^2$ between the transceiver and target points in the enclosure. We experimentally demonstrate the method using a flat microwave billiard and quantify the reconstruction quality as a function of enclosure loss, port coupling and other considerations.

  13. Numerical Analysis of Nanofluids in Differentially Heated Enclosure Undergoing Orthogonal Rotation

    Directory of Open Access Journals (Sweden)

    H. Saleh

    2014-01-01

    Full Text Available Natural convection heat transfer in a rotating, differentially heated enclosure is studied numerically in this paper. The rotating enclosure is filled with water-Ag, water-Cu, water-Al2O3, or water-TiO2 nanofluids. The governing equations are in velocity, pressure, and temperature formulation and solved using the staggered grid arrangement together with MAC method. The governing parameters considered are the solid volume fraction, 0.0 ≤ ϕ ≤ 0.05, and the rotational speeds, 3.5≤ Ω ≤ 17.5 rpm, and the centrifugal force is smaller than the Coriolis force and both forces were kept below the buoyancy force. It is found that the angular locations of the local maximums heat transfer were sensitive to rotational speeds and nanoparticles concentration. The global quantity of heat transfer rate increases about 1.5%, 1.1%, 0.8%, and 0.6% by increasing 1% ϕ of the nanoparticles Ag, Cu, Al2O3, and TiO2, respectively, for the considered rotational speeds.

  14. A case study of view-factor rectification procedures for diffuse-gray radiation enclosure computations

    Science.gov (United States)

    Taylor, Robert P.; Luck, Rogelio

    1995-01-01

    The view factors which are used in diffuse-gray radiation enclosure calculations are often computed by approximate numerical integrations. These approximately calculated view factors will usually not satisfy the important physical constraints of reciprocity and closure. In this paper several view-factor rectification algorithms are reviewed and a rectification algorithm based on a least-squares numerical filtering scheme is proposed with both weighted and unweighted classes. A Monte-Carlo investigation is undertaken to study the propagation of view-factor and surface-area uncertainties into the heat transfer results of the diffuse-gray enclosure calculations. It is found that the weighted least-squares algorithm is vastly superior to the other rectification schemes for the reduction of the heat-flux sensitivities to view-factor uncertainties. In a sample problem, which has proven to be very sensitive to uncertainties in view factor, the heat transfer calculations with weighted least-squares rectified view factors are very good with an original view-factor matrix computed to only one-digit accuracy. All of the algorithms had roughly equivalent effects on the reduction in sensitivity to area uncertainty in this case study.

  15. InfuShield: a shielded enclosure for administering therapeutic radioisotope treatments using standard syringe pumps.

    Science.gov (United States)

    Rushforth, Dominic P; Pratt, Brenda E; Chittenden, Sarah J; Murray, Iain S; Causer, Louise; Grey, Matthew J; Gear, Jonathan I; Du, Yong; Flux, Glenn D

    2017-03-01

    The administration of radionuclide therapies presents significant radiation protection challenges. The aim of this work was to develop a delivery system for intravenous radioisotope therapies to substantially moderate radiation exposures to staff and operators. A novel device (InfuShield) was designed and tested before being used clinically. The device consists of a shielded enclosure which contains the therapeutic activity and, through the hydraulic action of back-to-back syringes, allows the activity to be administered using a syringe pump external to the enclosure. This enables full access to the pump controls while simultaneously reducing dose to the operator. The system is suitable for use with all commercially available syringe pumps and does not require specific consumables, maximising both the flexibility and economy of the system. Dose rate measurements showed that at key stages in an I mIBG treatment procedure, InfuShield can reduce dose to operators by several orders of magnitude. Tests using typical syringes and infusion speeds show no significant alteration in administered flow rates (maximum of 1.2%). The InfuShield system provides a simple, safe and low cost method of radioisotope administration.

  16. 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.

  17. Space-deployed, thin-walled enclosure for a cryogenically-cooled high temperature superconducting coil

    Science.gov (United States)

    Porter, Allison K.

    The interaction of magnetic fields generated by large superconducting coils has multiple applications in space, including actuation of spacecraft or spacecraft components, wireless power transfer, and shielding of spacecraft from radiation and high energy particles. These applications require coils with major diameters as large as 20 meters and a thermal management system to maintain the superconducting material of the coil below its critical temperature. Since a rigid thermal management system, such as a heat pipe, is unsuitable for compact stowage inside a 5 meter payload fairing, a thin-walled thermal enclosure is proposed. A 1.85 meter diameter test article consisting of a bladder layer for containing chilled nitrogen vapor, a restraint layer, and multilayer insulation was tested in a custom toroidal vacuum chamber. The material properties found during laboratory testing are used to predict the performance of the test article in low Earth orbit. Deployment motion of the same test article was measured using a motion capture system and the results are used to predict the deployment in space. A 20 meter major diameter and coil current of 6.7 MA is selected as a point design case. This design point represents a single coil in a high energy particle shielding system. Sizing of the thermal and structural components of the enclosure is completed. The thermal and deployment performance is predicted.

  18. 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.

  19. Boundary conditions for the solution of the 3-dimensional Poisson equation in open metallic enclosures

    CERN Document Server

    Biswas, Debabrata; Kumar, Raghwendra

    2015-01-01

    Numerical solution of the Poisson equation in metallic enclosures, open at one or more ends, is important in many practical situations such as High Power Microwave (HPM) or photo-cathode devices. It requires imposition of a suitable boundary condition at the open end. In this paper, methods for solving the Poisson equation are investigated for various charge densities and aspect ratios of the open ends. It is found that a mixture of second order and third order local asymptotic boundary condition (ABC) is best suited for large aspect ratios while a proposed non-local matching method, based on the solution of the Laplace equation, scores well when the aspect ratio is near unity for all charge density variations, including ones where the centre of charge is close to an open end or the charge density is non-localized. The two methods complement each other and can be used in electrostatic calculations where the computational domain needs to be terminated at the open boundaries of the metallic enclosure.

  20. 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)

  1. Analysis of explosion in enclosure based on improved method of images

    Science.gov (United States)

    Wu, Z.; Guo, J.; Yao, X.; Chen, G.; Zhu, X.

    2017-03-01

    The aim of this paper is to present an improved method to calculate the pressure loading on walls during a confined explosion. When an explosion occurs inside of an enclosure, reflected shock waves produce multiple pressure peaks at a given wall location, especially at the corners. The effects of confined blast loading may bring about more serious damage to the structure due to multiple shock reflection. An approach, first proposed by Chan to describe the track of shock waves based on the mirror reflecting theory, using the method of images (MOI) is proposed to simplify internal explosion loading calculations. An improved method of images is proposed that takes into account wall openings and oblique reflections that cannot be considered with the standard MOI. The approach, validated using experimental data, provides a simplified and quick approach for loading calculation of a confined explosion. The results show that the peak overpressure tends to decline as the measurement point moves away from the center, and increases sharply as it approaches the enclosure corners. The specific impulse increases from the center to the corners. The improved method is capable of predicting pressure-time history and impulse with an accuracy comparable to that of three-dimensional AUTODYN code predictions.

  2. Numerical study of natural convection characteristics of nanofluids in an enclosure using multiphase model

    Science.gov (United States)

    Chen, Yan-Jun; Wang, Ping-Yang; Liu, Zhen-Hua

    2016-11-01

    The natural convective heat transfer and flow characteristics of nanofluids in an enclosure are numerically simulated using the multiphase-flow model and single phase model respectively. The simulated results are compared with the experimental results from the published papers to investigate the applicability of these models for nanofluids from a macro standpoint. The effects of Rayleigh number, Grashof number and volume concentration of nanoparticles on the heat transfer and flow characteristics are investigated and discussed. Comparisons of the horizontal and vertical central dimensionless velocity profiles between nanofluid and water for various Grashof numbers are studied. In addition, both streamline contours and isotherms lines for different volume concentrations of nanofluids are analyzed as well. The study results show that a great deviation exists between the simulated result of the single phase model and the experimental data on the relation of Nusselt number and Rayleigh number, which indicates that the single phase model cannot reflect the heat transfer characteristic of nanofluid. While the simulated results using the multiphase-flow model show a good agreement with the experimental data of nanofluid, which means that the multiphase-flow model is more suitable for the numerical study of nanofluid. For the natural convection, the present study holds the point that using Grashof numbers as the benchmark would be more appropriate to describe the heat transfer characteristics of nanofluid. Moreover, the simulated results demonstrate that adding nanoparticles into the base fluid can enhance both the motion of fluid and convection in the enclosure significantly.

  3. Effects of artificial enclosure of young lettuce leaves on tipburn incidence and leaf calcium concentration

    Science.gov (United States)

    Barta, D. J.; Tibbitts, T. W.

    1986-01-01

    The young developing leaves of 20-day-old lettuce plants (Lactuca sativa L. 'Buttercrunch') were enclosed by aluminized polyethylene sheaths to decrease transpiration and reduce Ca transport. The plants were grown in recirculating solution culture system using a modified half-strength Hoagland's solution under cool-white fluorescent lamps with a photosynthetic photon flux of 350 micromoles s-1 m-2 in a 16:8-hr (light:dark) period. Air temperature and humidity were 20 degrees C and 65%, respectively. After 4 days of enclosure, 53% of the inner leavers (leaves one to 3 cm in length) were tipburned. After the same period, less than 1% of the inner leaves on control plants were tipburned. The concentration of Ca in enclosed inner leaves was 0.63 mg g-1 dry weight, compared to 1.48 mg g-1 dry weight in inner leaves that were not enclosed. The Ca concentration in transpiring outer leaves of all plants was 9.9 mg g-1 dry weight. The Mg concentration in enclosed inner leaves was 2.25 mg g-1 dry weight, compared to 2.34 mg g-1 dry weight in inner leaves that were not enclosed. This research documents that enclosures of leaves at the growing point, as would occur with normal head development, is sufficient to create a limiting concentration of Ca in the enclosed tissue and encourage tipburn development.

  4. Numerical study of mixed convection heat transfer from a rotating cylinder inside a trapezoidal enclosure

    Science.gov (United States)

    Khan, Mohammed; Khan, Arham Amin; Hasan, Mohammad Nasim

    2016-07-01

    This article reports a numerical investigation of mixed convection heat transfer phenomena around an active rotating heated cylinder placed inside a trapezoidal enclosure. The cavity is configured such that top and bottom walls remain thermally insulated while the remaining two sidewalls experience a constant cold temperature. The heated cylinder is located at the centre of the trapezoidal enclosure and undergoes counter clockwise rotation. The numerical solution of various governing equations (i.e. continuity, momentum and energy equations) for the present problem is obtained by using Galerkin finite element method. The present study focused on the influence of the variation of inertia effect of the rotating cylinder as manifested by the parameter, Reynolds number (Re) for various Grashof number (Gr) ranging from 103 to 105 while keeping the Richardson number constant as 1, which essentially represents the case of pure mixed convection. An envision of flow field and thermal field has been made by studying the streamlines, isotherms respectively while for the study of heat transfer characteristics, local and average Nusselt number over the heated cylinder has been considered. The result indicates that both the side wall inclination angle as well as the inertia effect of the rotating cylinder has greater impact on heat transfer characteristics compared to the case of motionless heated cylinder placed in a square cavity.

  5. Software control of the Advanced Technology Solar Telescope enclosure PLC hardware using COTS software

    Science.gov (United States)

    Borrowman, Alastair J.; de Bilbao, Lander; Ariño, Javier; Murga, Gaizka; Goodrich, Bret; Hubbard, John R.; Greer, Alan; Mayer, Chris; Taylor, Philip

    2012-09-01

    As PLCs evolve from simple logic controllers into more capable Programmable Automation Controllers (PACs), observatories are increasingly using such devices to control complex mechanisms1, 2. This paper describes use of COTS software to control such hardware using the Advanced Technology Solar Telescope (ATST) Common Services Framework (CSF). We present the Enclosure Control System (ECS) under development in Spain and the UK. The paper details selection of the commercial PLC communication library PLCIO. Implemented in C and delivered with source code, the library separates the programmer from communication details through a simple API. Capable of communicating with many types of PLCs (including Allen-Bradley and Siemens) the API remains the same irrespective of PLC in use. The ECS is implemented in Java using the observatory's framework that provides common services for software components. We present a design following a connection-based approach where all components access the PLC through a single connection class. The link between Java and PLCIO C library is provided by a thin Java Native Interface (JNI) layer. Also presented is a software simulator of the PLC based upon the PLCIO Virtual PLC. This creates a simulator operating below the library's API and thus requires no change to ECS software. It also provides enhanced software testing capabilities prior to hardware becoming available. Results are presented in the form of communication timing test data, showing that the use of CSF, JNI and PLCIO provide a control system capable of controlling enclosure tracking mechanisms, that would be equally valid for telescope mount control.

  6. 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

  7. Construction of a Post-Irradiated Fuel Examination Shielded Enclosure Facility

    Energy Technology Data Exchange (ETDEWEB)

    Michael A. Lehto, Ph.D.; Boyd D. Christensen

    2008-05-01

    The U.S. Department of Energy (DOE) has committed to provide funding to the Idaho National Laboratory (INL) for new post-irradiation examination (PIE) equipment in support of advanced fuels development. This equipment will allow researchers at the INL to accurately characterize the behavior of experimental test fuels after they are removed from an experimental reactor also located at the INL. The accurate and detailed characterization of the fuel from the reactor, when used in conjunction with computer modeling, will allow DOE to more quickly understand the behavior of the fuel and to guide further development activities consistent with the missions of the INL and DOE. Due to the highly radioactive nature of the specimen samples that will be prepared and analyzed by the PIE equipment, shielded enclosures are required. The shielded cells will be located in the existing Analytical Laboratory (AL) basement (Rooms B-50 and B-51) at the INL Material and Fuels Complex (MFC). AL Rooms B-50 and B-51 will be modified to establish an area where sample containment and shielding will be provided for the analysis of radioactive fuels and materials while providing adequate protection for personnel and the environment. The area is comprised of three separate shielded cells for PIE instrumentation. Each cell contains an atmosphere interface enclosure (AIE) for contamination containment. The shielding will provide a work area consistent with the as-low-as-reasonably-achievable (ALARA) concept, assuming a source term of 10 samples in each of the three shielded areas. Source strength is assumed to be a maximum of 3 Ci at 0.75 MeV gamma for each sample. Each instrument listed below will be installed in an individual shielded enclosure: Shielded electron probe micro-analyzer (EPMA) Focused ion beam instrument (FIB) Micro-scale x-ray diffractometer (MXRD). The project is designed and expected to be built incrementally as funds are allocated. The initial phase will be to fund the

  8. [Diurnal and Seasonal Dynamic Variation of Soil Respiration and Its Influencing Factors of Different Fenced Enclosure Years in Desert Steppec].

    Science.gov (United States)

    Cui, Hai; Zhang, Ya-hong

    2016-04-15

    The fenced measures could improve the ecological environment of degraded grassland, it's a main measure for restoration of degraded grassland vegetation in China. Soil respiration (Rs) is an important component of an ecosystem's carbon cycle and the main pathway for carbon moving from the ecosystem to the atmosphere. In order to explore soil respiration characteristics and influencing factors of the different fenced years in arid desert grassland, we continuously observed Rs rate and environmental factors in the growing season of fenced enclosure 11a, 7a and no fenced (CK) desert steppe in Ningxia. The results showed that: (1) Both the diurnal andseasonal variations of Rs rate showed a single asymmetric peak changing in fenced enclosure of 11 years, 7 years, CK desert steppe. On the daily scale, the maximum and minimum values of Rs rate were found in the periods of 12:00-16:00 and 00:00-06:00,respectively. On the seasonal variation scale, the maximum value of Rs rate occurred in August with suitable precipitation and temperature conditions. And the Rs rate of the growing season of different fenced enclosure years was in the order of 11a [0.143 g · (m² · h)⁻¹] > 7a [0.138 g · (m² · h)⁻¹] > CK [0.106 g · (m2 - h)⁻¹]. (2) According to statistical analysis, it indicated that R² rate had a significant exponential positive relationship with air and soil temperature in fenced enclosure of 11 years, 7 years, CK desert steppe (P soil surface temperature (R²: 0.408-0.413) > air temperature (R2: 0.355-0.376) > 5-20 cm soil temperature (R2: 0.263-0.394). The temperature sensitivity coefficient Q, increased gradually with the soil depth, and Q1, of different fenced enclosure years was showed as 11 a (2.728) > 7a (2.436) > CK (2.086). (3) A significant quadratic function model (P soil moisture content of fenced enclosure 11a, 7a and CK desert steppe in the whole growing season. Rs rate had a significant linear negative correlation with air carbon dioxide

  9. Design and performance characteristics of an electromagnetic interference shielded enclosure for high voltage Pockels cell switching system

    Indian Academy of Sciences (India)

    A K Sharma; K K Mishra; M Raghuramaiah; P A Naik; P D Gupta

    2007-06-01

    An electro-magnetic interference noise shielding enclosure for Pockels cells for high speed synchronized switching has been set-up and tested. The shielding effectiveness of the aluminum enclosures housing the Pockels cells and the electronic circuitry has been measured using a high impedance probe and is found to be $\\sim 50 dB$. This ensures a noise-free and synchronized electro-optic switching in an Nd:glass re-generative amplifier of chirped pulse amplification based table top terawatt laser system.

  10. Three-dimensional natural convection of a fluid with temperature-dependent viscosity in an enclosure with localized heating

    Science.gov (United States)

    Torczynski, J. R.; Henderson, J. A.; Ohern, T. J.; Chu, T. Y.; Blanchat, T. K.

    Three-dimensional natural convection of a fluid in an enclosure is examined. The geometry is motivated by a possible magmaenergy extraction system, and the fluid is a magma simulant and has a highly temperature-dependent viscosity. Flow simulations are performed for enclosures with and without a cylinder, which represents the extractor, using the finite-element code FIDAP (Fluid Dynamics International). The presence of the cylinder completely alters the flow pattern. Flow-visualization and PIV experiments are in qualitative agreement with the simulations.

  11. Measurement of Moisture in Wood for Application in the Restoration of Old Buildings

    Directory of Open Access Journals (Sweden)

    Carlos Moron

    2016-05-01

    Full Text Available There are many historic buildings whose construction is based on timber frame walls. Most buildings built during the nineteenth and early twentieth centuries were based on timber frame walls with vertical support elements. These timber frame elements are affected by their moisture content and by the passage of time. If the interaction of the timber frame walls with hygrothermal fluctuations were known, the maintenance of these buildings could be improved significantly. To determine the moisture content of wood there are two types of meters on the market: on the one hand, capacitance meters which consist of two side ends and where the moisture content is measured locally between two peaks. On the other hand, there are meters based on the variation of electromagnetic transmittance of timber, which depends on the moisture of timber. The second ones are very expensive and difficult to handle. This work presents a new non-intrusive capacitive sensor that measures the global moisture content in a section of the timber frame walls and therefore its accuracy is similar to the accuracy that can be obtained with electromagnetic transmittance meters. Additionally, as it is a capacitive sensor, it is low cost and easy to operate.

  12. Measurement of Moisture in Wood for Application in the Restoration of Old Buildings.

    Science.gov (United States)

    Moron, Carlos; Garcia-Fuentevilla, Luisa; Garcia, Alfonso; Moron, Alberto

    2016-05-14

    There are many historic buildings whose construction is based on timber frame walls. Most buildings built during the nineteenth and early twentieth centuries were based on timber frame walls with vertical support elements. These timber frame elements are affected by their moisture content and by the passage of time. If the interaction of the timber frame walls with hygrothermal fluctuations were known, the maintenance of these buildings could be improved significantly. To determine the moisture content of wood there are two types of meters on the market: on the one hand, capacitance meters which consist of two side ends and where the moisture content is measured locally between two peaks. On the other hand, there are meters based on the variation of electromagnetic transmittance of timber, which depends on the moisture of timber. The second ones are very expensive and difficult to handle. This work presents a new non-intrusive capacitive sensor that measures the global moisture content in a section of the timber frame walls and therefore its accuracy is similar to the accuracy that can be obtained with electromagnetic transmittance meters. Additionally, as it is a capacitive sensor, it is low cost and easy to operate.

  13. Building calculations

    DEFF Research Database (Denmark)

    Jensen, Bjarne Christian; Hansen, Svend Ole

    Textbook on design of large panel building including rules on robustness and a method for producing the Statical documentattion......Textbook on design of large panel building including rules on robustness and a method for producing the Statical documentattion...

  14. Building America

    Energy Technology Data Exchange (ETDEWEB)

    Brad Oberg

    2010-12-31

    IBACOS researched the constructability and viability issues of using high performance windows as one component of a larger approach to building houses that achieve the Building America 70% energy savings target.

  15. Systematization of the environmental conditioning project in buildings with a view to optimizing the architectural projects with ragard to environmental control and energy saving. Volume 3. Sistematizacion del proyecto de acondicionamiento ambiental en la edificacion con vistas a la optimizacion de los proyectos arquitectonicos en aspectos de control ambiental y ahorro energetico

    Energy Technology Data Exchange (ETDEWEB)

    Klainsek, J.C.

    1988-07-01

    Due to its significance, energy analysis should be taken into account in both developing and optimization of hygrothermic conditioning system and new building designs. It is also necessary to determine the actual costs of energy saving and conservation modifications for existing buildings. This analysis involves a large number of repetitive calculations, so a computer application has become a necessity and a computer program has been developed to simulate energy needs for a real life office and their functions in one climate region. This program predicts heating and cooling energy requirements. The purpose of the present study is to determine the affect of envelope parameters: orientation, external walls, glazing, shadings, glass-to-wall ratio, surface absorbance of external wells (color), roofs, upon energy saving and conservation for a typical office building in Madrid.

  16. Systematization of the environmental conditioning project in buildings with a view to optimizing the architectural projects with regard to environmental control and energy saving. Sistematizacion del proyecto de acondicionamiento ambiental en la edificacion con vistas a la optimizacion de los proyectos arquitectonicos en aspectos de control ambiental y ahorro energetico

    Energy Technology Data Exchange (ETDEWEB)

    Klainsek, J.C.

    1988-07-01

    Due to its significance, energy analysis should be taken into account in both developing and optimization of hygrothermic conditioning system and new building designs. It is also necessary to determine the actual costs of energy saving and conservation modifications for existing buildings. This analysis involves a large number of repetitive calculations, so a computer application has become a necessity and a computer program has been developed to simulate energy needs for a real life office and their functions in one climate region. This program predicts heating and cooling energy requirements. The purpose of the present study is to determine the effect of envelope parameters: orientation, external walls, glazing, shadings, glass-to-wall ratio, surface absorbance of external walls (color), roofs, upon energy saving and conservation for a typical office building in Madrid.

  17. Systematization of the environmental conditioning project in buildings with a view to optimizing the architectural projects with regard to environmental control and energy saving. Volume 1. Sistematizacion del proyecto de acondicionamiento ambiental en la edificacion con vistas a la optimizacion de los proyectos arquitectonicos en aspectos de control ambiental y ahorro energetico

    Energy Technology Data Exchange (ETDEWEB)

    Klainsek, J.C.

    1988-07-01

    Due to its significance, energy analysis should be taken into account in both developing and optimization of hygrothermic conditioning system and new building designs. It is also necessary to determine the actual costs of energy saving and conservation modifications for existing buildings. This analysis involves a large number of repetitive calculations, so a computer application has become a necessity and a computer program has been developed to simulate energy needs for a real life office and their functions in one climate region. This program predicts heating and cooling energy requirements. The purpose of the present study is to determine the affect of envelope parameters: orientation, external walls, glazing, shadings, glass-to-wall ratio, surface absorbance of external well (color), roofs, upon energy saving and conservation for a typical office building in Madrid.

  18. Solar building

    OpenAIRE

    Zhang, Luxin

    2014-01-01

    In my thesis I describe the utilization of solar energy and solar energy with building integration. In introduction it is also mentioned how the solar building works, trying to make more people understand and accept the solar building. The thesis introduces different types of solar heat collectors. I compared the difference two operation modes of solar water heating system and created examples of solar water system selection. I also introduced other solar building applications. It is conv...

  19. Healthy Buildings?

    Science.gov (United States)

    Grubb, Deborah

    Health problems related to school buildings can be categorized in five major areas: sick-building syndrome; health-threatening building materials; environmental hazards such as radon gas and asbestos; lead poisoning; and poor indoor air quality due to smoke, chemicals, and other pollutants. This paper provides an overview of these areas,…

  20. Building envelope

    CSIR Research Space (South Africa)

    Gibberd, Jeremy T

    2009-01-01

    Full Text Available This chapter describes the way building envelopes can contribute to developing green buildings and sets out some objectives that could be aimed for. It also proposes a number of approaches that can be used to help design green building envelopes...

  1. Análise do efeito higrotérmico no comportamento em fadiga de compósitos de PPS/fibras de carbono On the analysis of hygrothermal effect on fatigue behavior of PPS/carbon fiber composite

    Directory of Open Access Journals (Sweden)

    Maria C. M. de Faria

    2012-01-01

    exposed to harsh environments such as high temperature and humidity, and should be carefully evaluated before being put into service. The aim of the present work is to evaluate the hygrothermal effect on the fatigue resistance of thermoplastic PPS/carbon fiber composite. These laminates were obtained from TenCate Company, which provides composite laminates to Airbus and Embraer. PPS/carbon fibers composites exhibited increased tensile strength under hygrothermal conditioning due to plasticization of the polymer matrix, with the fracture toughness being also increased. In contrast, the hygrothermal conditioning did not alter significantly the behavior of fatigue life of laminates from PPS/carbon fiber composite.

  2. Sustainable building versus ecological building

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2010-04-01

    Full Text Available and sensitivity to a site that are required to efficiently meet the energy needs of a building and occupants with renewable energy (solar, wind, geothermal, etc), designers must apply holistic design principles and take advantage of the free, naturally... Building Handbook Volume 1 Sustainable Building versus Ecological Building Llewellyn van Wyk Principal Researcher CSIR Background and Context ?Evidence is mounting that humankind, and the environment that shapes its existence, are in the midst...

  3. Persistence and distribution of 4-nonylphenol following repeated application to littoral enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Heinis, L.J.; Liber, K.; Tunell, R.L. [Univ. of Wisconsin, Superior, WI (United States). Lake Superior Research Inst.; Knuth, M.L.; Sheedy, B.R.; Ankley, G.T. [Environmental Protection Agency, Duluth, MN (United States). Mid-Continent Ecology Div.

    1999-03-01

    The persistence and distribution of 4-nonylphenol (NP) were monitored for 440 d, following application to 18 littoral enclosures situated in a 2-ha mesotrophic pond near Duluth, Minnesota. Application was accomplished by subsurface, gravity-fed injection over a 20-d period, with a 2-d frequency, to achieve nominal aqueous concentrations of 0, 3, 30, 100, and 300 {micro}g/L. Mean maximum concentrations in the water over the 20-d application period ranged from 75.7 to 81.0% of nominal for the three highest treatment levels and was 181% of nominal at the lowest treatment level. Water was the major compartment, on a mass balance basis, for NP until 2 to 4 d after the application period, with a mean time to 50% dissipation (DT50) of 0.74 d and a mean time to 95% dissipation (DT95) of 13.8 d. 4-Nonylphenol partitioned to enclosure wall material, macrophytes, and sediment within 2 d of initial application. Macrophytes accumulated maximum NP concentrations of 11.5 and 139 mg/kg 1 to 2 d after the application period at the 30- and 300-{micro}g/L treatment levels, respectively. Mean DT50 and DT95 estimates of NP persistence in/on the macrophytes were 10.3 and 189 d, respectively. Sediment from the 30- and 300-{micro}g/L treatments accumulated maximum dry weight NP concentrations of 2.74 and 27.4 mg/kg, respectively within 20 to 48 d of the first application. The mean sediment porewater NP concentration was 18.6 {micro}g/L for the period 2 to 34 d after application 1 at the 300-{micro}g/L treatment. The sediment was the primary sink for NP 440 d after the initial application with a concentration of 1.97 mg/kg at the 300-{micro}g/L treatment. Mean sediment DT50 and DT95 values were 66.0 and 401 d, respectively, indicating a long-term persistence of NP. Ecocores collected 1 d after the final NP application did not show significant decreases in sediment NP concentration during a 55-d incubation period, corroborating the NP persistence observed in the littoral enclosures.

  4. Retrofit of a MultiFamily Mass Masonry Building in New England

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation, Somerville, MA (United States); Kerrigan, P. [Building Science Corporation, Somerville, MA (United States); Wytrykowska, H. [Building Science Corporation, Somerville, MA (United States); Van Straaten, R. [Building Science Corporation, Somerville, MA (United States)

    2013-08-01

    Merrimack Valley Habitat for Humanity (MVHfH) has partnered with Building Science Corporation to provide high performance affordable housing for 10 families in the retrofit of an existing brick building (a former convent) into condominiums. The research performed for this project provides information regarding advanced retrofit packages for multi-family masonry buildings in Cold climates. In particular, this project demonstrates safe, durable, and cost-effective solutions that will potentially benefit millions of multi-family brick buildings throughout the East Coast and Midwest (Cold climates). The retrofit packages provide insight on the opportunities for and constraints on retrofitting multifamily buildings with ambitious energy performance goals but a limited budget. The condominium conversion project will contribute to several areas of research on enclosures, space conditioning, and water heating. Enclosure items include insulation of mass masonry building on the interior, airtightness of these types of retrofits, multi-unit building compartmentalization, window selection, and roof insulation strategies. Mechanical system items include combined hydronic and space heating systems with hydronic distribution in small (low load) units, and ventilation system retrofits for multifamily buildings.

  5. Large eddy simulations of targeted electromagnetic control of buoyancy-driven turbulent flow in a slender enclosure

    NARCIS (Netherlands)

    Kenjeres, S.

    2009-01-01

    We conducted a large eddy simulation (LES) of a locally applied electromagnetic control of turbulent thermal convection of an electrically conductive fluid (electrolyte solution) inside of a slender enclosure. Generic configurations, consisting of two or three magnets of opposite polarities located

  6. Preliminary Safety Analysis Report for the Transuranic Storage Area Retrieval Enclosure at the Idaho National Engineering Laboratory. Revision 8

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. NUMERICAL STUDY ON SORET-EFFECT AND DUFOUR-EFFECT FOR DOUBLE-DIFFUSIVE NATURAL CONVECTION IN POROUS ENCLOSURE

    Institute of Scientific and Technical Information of China (English)

    Chen Bao-ming; Zhang Li-qiang; Wang Bu-xuan

    2003-01-01

    The influences of Soret effect and Dufour effect on the natural convection and heat and mass transfer for a porous enclosure were investigated by means of the penalty finite element method. Numerical results indicate that the Soret and Dufour effects have significant influences on heat and mass transfer in the presence of large temperature gradient and concentration gradient.

  8. Microbial eukaryotic community in response to Microcystis spp. bloom, as assessed by an enclosure experiment in Lake Taihu, China.

    Science.gov (United States)

    Chen, Meijun; Chen, Feizhou; Xing, Peng; Li, Huabing; Wu, Qinglong L

    2010-10-01

    Mesocosm experiments were carried out to examine the potential impacts of Microcystis blooms on microbial eukaryotic community composition (MECC). Four treatment additions of differing Microcystis spp. biomass were performed in enclosures, as indicated by chlorophyll a concentrations from 15 to 3217 μg L(-1) in the water column. Dialysis bags were used in enclosures to measure MECC dynamics without influence from predation and irradiance. Samples were taken on days 0, 1 and 4 for MECC analysis, based on changes in the chemical parameters during simultaneous monitoring. The MECC were determined by terminal restriction fragment length polymorphism (T-RFLP), followed by cloning and sequencing of 18S rRNA genes of selected samples. T-RFLP and clone library analysis revealed that MECC in enclosures and dialysis bags shifted strongly during Microcystis spp. decomposition. Members belonging to fungi became the dominant organisms in enclosures with a high biomass of Microcystis spp. Canonical correspondence analysis indicated that temporal changes in MECC were mostly related to changes in the pH and concentrations of dissolved oxygen and dissolved organic carbon, which were induced by the addition of Microcystis spp. The experiment suggests that accumulation of Microcystis biomass can strongly impact MECC, and there might be a saprophytic association between fungi and the decomposition of Microcystis biomass.

  9. Negative effects of Microcystis blooms on the crustacean plankton in an enclosure experiment in the subtropical China

    Institute of Scientific and Technical Information of China (English)

    CHEN Fei-zhou; XIE Ping; TANG Hui-juan; LIU Hong

    2005-01-01

    Effects of Microcystis blooms on the crustacean plankton were studied using enclosure experiments during July-September,2000. Eight enclosures were set in the hypereutrophic Donghu Lake. Different nutrient concentrations through additional nutrient and sediment in enclosures were expected to result in different abundance of Microcystis. From July to early August, the phytoplankton community was dominated by Chlorophyta, Cryptophyta, Bacillariophyta and Cyanophyta other than Microcystis aeruginosa. M. aeruginosa showed a rapid increase during early August in all enclosures and predominated. Crustacean plankton was dominated by the herbivorous Moina micrura, Diaphanosoma brachyurum and Ceriodaphnia cornuta, and the predaceous Mesocyclops sp. and Thermocyclops taihokuensis. During the pre-bloom period, the dynamics of M. micrura population appeared to be mainly affected by the predaceous cyclopoids. With the development of Microcystis blooms, such interaction between M. micrura and cyclopoids seemed weakened, especially when the Microcystis biomass was high. But there was no apparent influence on the interaction between Leptodora kindti and its zooplanktonic prey. The density of two cyclopoids decreased with the enhancement of Microcystis. The density decline of M. micrura was caused by both predation and inhibition by Microcystis. The low food availability of other edible phytoplankton during the blooms led to low densities of both C. comuta and D. brachyurum by late August. lt appears that dense Microcystis blooms exert strong negative effects on the herbivorous cladocerans and the predaceous cyclopoids.

  10. 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.

  11. Effects of dredging and lanthanum-modified clay on water quality variables in an enclosure study in a hypertrophic pond

    NARCIS (Netherlands)

    Lürling, Miquel; Waajen, Guido; Engels, Bart; Oosterhout, van Frank

    2017-01-01

    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.

  12. Numerical investigation of natural convection heat transfer in a cylindrical enclosure due to ultrasonic vibrations.

    Science.gov (United States)

    Talebi, Maryam; Setareh, Milad; Saffar-Avval, Majid; Hosseini Abardeh, Reza

    2017-04-01

    Application of ultrasonic waves for heat transfer augmentation has been proposed in the last few decades. Due to limited researches on acoustic streaming induced by ultrasonic oscillation, the effect of ultrasonic waves on natural convection heat transfer is the main purpose of this paper. At first, natural convection on up-ward-facing heating surface in a cylindrical enclosure filled with air is investigated numerically by the finite difference method, then the effect of upper surface oscillation on convection heat transfer is considered. The conservation equations in Lagrangian approach and compressible fluid are assumed for the numerical simulation. Results show that acoustic pressure will become steady after some milliseconds also pressure oscillation amplitude and acoustic velocity components will be constant therefore steady state velocity is used for solving energy equation. Results show that Enhancement of heat transfer coefficient can be up to 175% by induced ultrasonic waves. In addition, the effect of different parameters on acoustic streaming and heat transfer has been studied.

  13. The theory and technology of enclosure dust-laying model in speeded advance of coal road

    Energy Technology Data Exchange (ETDEWEB)

    Wei-Min Cheng; Xiang-Sheng Liu; Guo-Qiang Ruan; Yun-Xiang Guo; Gang Wang [Shandong University of Science and Technology, Qingdao (China). Key Laboratory of Mine Disaster Prevention and Control

    2009-02-15

    In order to solve the problem of high dust concentration caused by the rapid advance of coal roadways using the ABM20 development machine, a method suitable for the rapid advance of coal roadways in China was proposed. By using the mathematic model method to contrast the wind current field and dust field of the drivage face under different drivage velocities, an optimized drivage velocity of the fully-mechanized development machine was obtained. The theories were tested in an industry experiment. Analysis of the data indicates that the proposed enclosure dust-laying system can significantly lower the dust concentration at the heading face. It also has some advantages in accomplishing the effective advance of coal mines. 9 refs., 5 figs.

  14. Standard Test Method for Hail Impact Resistance of Aerospace Transparent Enclosures

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the determination of the impact resistance of an aerospace transparent enclosure, hereinafter called windshield, during hailstorm conditions using simulated hailstones consisting of ice balls molded under tightly controlled conditions. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 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 limitations prior to use. For specific hazard statements see Section 7.

  15. THE INTERACTION OF LIQUID DROPS WITH A ROTATING GAS STREAM WITHIN A RAPIDLY REVOLVING ANNULAR ENCLOSURE

    Directory of Open Access Journals (Sweden)

    A. AROUSSI

    2006-12-01

    Full Text Available The flow phenomena occurring around a rotating shaft are extremely complex and are a common feature in turbomachinery such as the bearing chambers of aero engines. As the liquid jet impinges onto the shaft, circumferential streams of lubricating liquid droplets centrifuge away from the rotor surface and impinge onto the inner circumference of the stationary case. A further break-up of drops occurred whilst rotating around the shaft before impacting on to the casing surface. Non-intrusive laser techniques have been employed to aid the visualisation processes and the analysis of the flow phenomena occurring within the rotating annular enclosure. Results reveal that, the liquid flow conditions and the shaft rotation regimes, along with the aerodynamic movement of the air circulating around the shaft influence the dynamics of the droplets and consequently the lubrication processes within the bearing chambers.

  16. Analysis of structural - acoustic coupling of elastic rectangular enclosure with arbitrary boundary conditions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The structural acoustic coupling characteristics of a rectangular enclosure consisting of two elastic supported flexible plates and four rigid plates are analyzed. A general formulation considering the full coupling between the plates and cavity is developed by using Hamiltonian function and Rayleigh-Ritz method. By means of continuous distributions of artificial springs along boundary of flexible plates, a wide variety of boundary conditions and structure joint conditions are considered. To demonstrate the validity of the analytical model,the responses of sound pressure in the cavity and plate velocity are worked out. The analytical results coincides well with Kim's experimental results. The result is satisfactory. Finally, analytical results on the structure vibration and the sound field inside the cavity are presented.These results indicate that the coupling of the combined structure is relatively weak, so the internal cavity sound is controlled by plate directly excited,and the translational stiffness affects the sound more than the rotational stiffness does.

  17. Conjugate Heat Transfer in Rayleigh-Bénard Convection in a Square Enclosure

    Directory of Open Access Journals (Sweden)

    Habibis Saleh

    2014-01-01

    Full Text Available Conjugate natural convection-conduction heat transfer in a square enclosure with a finite wall thickness is studied numerically in the present paper. The governing parameters considered are the Rayleigh number 5×103≤Ra≤106, the wall-to-fluid thermal conductivity ratio 0.5≤Kr≤10, and the ratio of wall thickness to its height 0.2≤D≤0.4. The staggered grid arrangement together with MAC method was employed to solve the governing equations. It is found that the fluid flow and the heat transfer can be controlled by the thickness of the bottom wall, the thermal conductivity ratio, and the Rayleigh number.

  18. Conjugate heat transfer in Rayleigh-Bénard convection in a square enclosure.

    Science.gov (United States)

    Saleh, Habibis; Hashim, Ishak

    2014-01-01

    Conjugate natural convection-conduction heat transfer in a square enclosure with a finite wall thickness is studied numerically in the present paper. The governing parameters considered are the Rayleigh number (5 × 10(3) ≤ Ra ≤ 10(6)), the wall-to-fluid thermal conductivity ratio (0.5 ≤ Kr ≤ 10), and the ratio of wall thickness to its height (0.2 ≤ D ≤ 0.4). The staggered grid arrangement together with MAC method was employed to solve the governing equations. It is found that the fluid flow and the heat transfer can be controlled by the thickness of the bottom wall, the thermal conductivity ratio, and the Rayleigh number.

  19. Electrohydrodynamic Nanofluid Hydrothermal Treatment in an Enclosure with Sinusoidal Upper Wall

    Directory of Open Access Journals (Sweden)

    Mohsen Sheikholeslami

    2015-08-01

    Full Text Available The influence of non-uniform electric filed on Fe3O4-Ethylene glycol nanofluid hydrothermal treatment in an enclosure with sinusoidal upper and moving lower walls is investigated in this study. Control Volume based Finite Element Method (CVFEM is utilized to simulate in the presented model. Numerical investigation are conducted for the sundry parameters such as Reynolds number; nanoparticle volume fraction and supplied. Results show that supplied voltage can change the flow shape. Coulomb force causes isotherms denser near the moving wall. Heat transfer rises with augment of supplied voltage and Reynolds number. Effect of electric filed on heat transfer is more pronounced at low Reynolds number. Finally, a comparison with the existing literature is also made.

  20. Energy transmission in a mechanically-linked double-wall structure coupled to an acoustic enclosure

    Science.gov (United States)

    Cheng, L.; Li, Y. Y.; Gao, J. X.

    2005-05-01

    The energy transmission in a mechanically linked double-wall structure into an acoustic enclosure is studied in this paper. Based on a fully coupled vibro-acoustic formulation, focus is put on investigating the effect of the air gap and mechanical links between the two panels on the energy transmission and noise insulation properties of such structures. An approximate formula reflecting the gap effect on the lower-order coupled frequencies of the system is proposed. A criterion, based on the ratio between the aerostatic stiffness of the gap cavity and the stiffness of the link, is proposed to predict the dominant transmitting path, with a view to provide guidelines for the design of appropriate control strategies. Numerical results reveal the existence of three distinct zones, within which energy transmission takes place following different mechanisms and transmitting paths. Corresponding effects on noise insulation properties of the double-wall structure are also investigated. .

  1. Thermosyphon assisted melting of PCM inside a rectangular enclosure:A synergistic numerical approach

    Science.gov (United States)

    Srikanth, R.; Nair, Rohit S.; Balaji, C.

    2016-09-01

    Melting of a phase change material assisted by a thermosyphon inside a two dimensional rectangular domain is numerically investigated. The PCM used is n-eicosane and the thermosyphon is made of copper. The working fluid is water. The fill ratio of the working fluid (water) is taken to be 50%. A lumped model is used for the simulation of transient operation of the thermosyphon and enthalpy-porosity method is employed for numerical simulation of melting of PCM. The effects of inclusion of multiple heat pipes on the melting of the PCM inside the enclosure is studied. Simulation results indicate that the addition of heat pipes enhances the performance of latent heat thermal energy storage system only upto a certain extent.

  2. Double-diffusive natural convection in an enclosure filled with nanofluid using ISPH method

    Directory of Open Access Journals (Sweden)

    Abdelraheem M. Aly

    2016-12-01

    Full Text Available The double-diffusive natural convection in an enclosure filled with nanofluid is studied using ISPH method. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. In addition the thermal energy equations include regular diffusion and cross-diffusion terms. In ISPH algorithm, a semi implicit velocity correction procedure is utilized and the pressure is implicitly evaluated by solving pressure Poisson equation. The results are presented with flow configurations, isotherms, concentration and nanoparticle volume fraction contours and average Nusselt and Sherwood numbers for different cases. The results from this investigation are well validated and have favorable comparisons with previously published results. It is found that, among all cases, a good natural convection can be obtained by considering the double diffusive case. An increase in Soret number accompanied by a decrease in Dufour number results in an increase in average Nusselt number and a decrease in average Sherwood number.

  3. Fiber Optic Tamper Indicating Enclosure (TIE); A Case Study in Authentication

    Energy Technology Data Exchange (ETDEWEB)

    Anheier, Norman C.; Benz, Jacob M.; Tanner, Jennifer E.; Westman, Matthew P.

    2015-07-15

    A robust fiber optic-based tamper-indicating enclosure (TIE) has been developed by PNNL through funding by the National Nuclear Security Administration Office of Nuclear Verification over the past few years. The objective of this work is to allow monitors to have confidence in both the authenticity and integrity of the TIE and the monitoring equipment inside, throughout the time it may be located at a host facility. Incorporating authentication features into the design were the focus of fiscal year 2014 development efforts. Throughout the development process, modifications have been made to the physical TIE design based on lessons learned via exercises and expert elicitation. The end result is a robust and passive TIE which can be utilized to protect monitoring party equipment left in a host facility.

  4. 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...

  5. Numerical modeling of turbulence mixed convection heat transfer in air filled enclosures by finite volume method

    Directory of Open Access Journals (Sweden)

    M Safaei

    2016-09-01

    Full Text Available In the present study, first the turbulent natural convection and then laminar mixed convection of air flow was solved in a room and the calculated outcomes are compared with results of other scientists and after showing validation of calculations, aforementioned flow is solved as a turbulent mixed convection flow, using the valid turbulence models Standard k-ε, RNG k-ε and RSM. To solve governing differential equations for this flow, finite volume method was used. This method is a specific case of residual weighting method. The results show that at high Richardson Numbers, the flow is rather stationary at the center of the enclosure. Moreover, it is distinguished that when Richardson Number increases the maximum of local Nusselt decreases. Therefore, it can be said that less number of Richardson Number, more rate of heat transfer.

  6. Experimental study of humidity distribution inside electronic enclosure and effect of internal heating

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan

    2016-01-01

    Corrosion reliability of electronic products is a key factor for electronics industry, and today there is a large demand for performance reliability in a wide range of temperature and humidity during day and night time periods. Corrosion failures are still a challenge due to the combined effects...... of temperature, humidity and corrosion accelerating species in the atmosphere. Moreover the surface region of printed circuit board assemblies is often contaminated by various aggressive chemical species.This study describes the overall effect of the exposure to severe climate conditions and internal heat cycles...... on the humidity and temperature profile inside typical electronic enclosures. Defined parameters include external temperature and humidity conditions, temperature and time of the internal heat cycle, thermal mass, and ports/openings size. The effect of the internal humidity on electronic reliability has been...

  7. Space use selectivity by chimpanzees and gorillas in an indoor-outdoor enclosure.

    Science.gov (United States)

    Ross, S R; Calcutt, S; Schapiro, S J; Hau, J

    2011-02-01

    Understanding the relationship between physical environments and nonhuman primate behavior is a key element for effective care and management in a range of settings. The physical features of the captive environment, including not only gross useable space but also environmental complexity, can have a significant influence on primate behavior and ultimately, animal welfare. But despite this connection, there remains relatively little conclusive data on how captive primates, especially great apes, use the spaces provided to them, especially in modern, indoor-outdoor enclosures that have become more prevalent in recent years. In this study, we used four years of detailed data on where 23 great apes (chimpanzees and gorillas) positioned themselves within a modern, indoor-outdoor zoo enclosure to determine not only how the apes utilized their space but also how access to outdoor areas affected their spatial selectivity. We found that both species used relatively little of their available space: chimpanzees and gorillas spent half their time in only 3.2 and 1.5% of their useable three-dimensional space, respectively. Chimpanzees utilized the outdoor space more than gorillas, but access to the outdoors did not affect space selectivity in the indoor area for either species. Although both species of ape were highly selective in their space use, consideration should be given to the importance of providing the choice to locate in a variety of spaces, including outdoor areas. These data represent an extremely detailed account of space selectivity by great apes in an indoor-outdoor environment and have substantial implications for future facility design and captive primate management.

  8. Assessment of human body influence on exposure measurements of electric field in indoor enclosures.

    Science.gov (United States)

    de Miguel-Bilbao, Silvia; García, Jorge; Ramos, Victoria; Blas, Juan

    2015-02-01

    Personal exposure meters (PEMs) used for measuring exposure to electromagnetic fields (EMF) are typically used in epidemiological studies. As is well known, these measurement devices cause a perturbation of real EMF exposure levels due to the presence of the human body in the immediate proximity. This paper aims to model the alteration caused by the body shadow effect (BSE) in motion conditions and in indoor enclosures at the Wi-Fi frequency of 2.4 GHz. For this purpose, simulation techniques based on ray-tracing have been carried out, and their results have been verified experimentally. A good agreement exists between simulation and experimental results in terms of electric field (E-field) levels, and taking into account the cumulative distribution function (CDF) of the spatial distribution of amplitude. The Kolmogorov-Smirnov (KS) test provides a P-value greater than 0.05, in fact close to 1. It has been found that the influence of the presence of the human body can be characterized as an angle of shadow that depends on the dimensions of the indoor enclosure. The CDFs show that the E-field levels in indoor conditions follow a lognormal distribution in the absence of the human body and under the influence of BSE. In conclusion, the perturbation caused by BSE in PEMs readings cannot be compensated for by correction factors. Although the mean value is well adjusted, BSE causes changes in CDF that would require improvements in measurement protocols and in the design of measuring devices to subsequently avoid systematic errors.

  9. Laboratory Building

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, Joshua M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    This report is an analysis of the means of egress and life safety requirements for the laboratory building. The building is located at Sandia National Laboratories (SNL) in Albuquerque, NM. The report includes a prescriptive-based analysis as well as a performance-based analysis. Following the analysis are appendices which contain maps of the laboratory building used throughout the analysis. The top of all the maps is assumed to be north.

  10. Laboratory Building.

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, Joshua M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    This report is an analysis of the means of egress and life safety requirements for the laboratory building. The building is located at Sandia National Laboratories (SNL) in Albuquerque, NM. The report includes a prescriptive-based analysis as well as a performance-based analysis. Following the analysis are appendices which contain maps of the laboratory building used throughout the analysis. The top of all the maps is assumed to be north.

  11. 湿热载荷下含损伤夹层板分层扩展判定分析%Delamination Growth of Composite Sandwich under Hygrothermal and Mechanical Loads

    Institute of Scientific and Technical Information of China (English)

    张志民; 李向阳

    2001-01-01

    The local buckling may occur in composite sandwich with delamination induced by impact damage. This often causes delamination growth and structure failure. The delamiantion growth is studied by using the variational method of moving boundary, and the formulas of energy release rate G along the delamination front are obtained. By employing Rayleigh-Ritz method, the hygrothermal effect on buckling character of composite sandwich plates containing delamination between two faceplate laminae is studied.%含面板内分层损伤的复合材料夹层板在承受压缩载荷时,很容易发生局部屈曲,导致分层扩展和结构失效,恶劣的湿热环境更是使之加剧.利用可动边界变分问题对分层扩展进行了分析,导出了分层边界的逐点能量释放率表达式,采用Rayleigh-Ritz法研究了任意的湿热环境对含损伤的复合材料夹层板分层扩展性能的影响.

  12. Acoustic modeling of a three-dimensional rectangular opened enclosure coupled with a semi-infinite exterior field at the baffled opening.

    Science.gov (United States)

    Jin, Guoyong; Shi, Shuangxia; Liu, Zhigang

    2016-11-01

    A modeling method is proposed for the acoustic analysis of a three-dimensional (3D) rectangular opened enclosure coupled with a semi-infinite exterior field by a rectangular opening of arbitrary size, and with general wall impedance. In contrast to existing modeling methods that solve the differential equations, the energy principle in combination with a 3D modified Fourier cosine series is employed in the present method for the modeling of this system. Under this theoretical framework, the effect of an opening in the wall of a rectangular enclosure is taken into account via the work done by the sound pressure acting on the opening between the finite enclosure and exterior domain. The sound pressure inside the opened enclosure is expressed as the combination of a 3D trigonometric cosine series and one supplementary 2D expansion introduced to ensure uniform convergence of the solution over the entire solution domain including opening boundary. The acoustic responses of the opened enclosure are obtained based on the energy expressions for the enclosure system. The effectiveness and reliability of the current method are checked against the results obtained by the boundary element method and experimental results, and excellent agreement is achieved. The effects of sizes and positions of the opening and wall impedance on the acoustic behaviors of opened enclosure system are investigated.

  13. 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.

  14. Enclosing the commons: reasons for the adoption and adaptation of enclosures in the arid and semi-arid rangelands of Chepareria, Kenya.

    Science.gov (United States)

    Wairore, John N; Mureithi, Stephen M; Wasonga, Oliver V; Nyberg, Gert

    2015-01-01

    The adoption and adaptation of enclosures in the arid and semi-arid rangelands of sub-Saharan Africa is driven and sustained by a combination of factors. However, reviews indicate that these factors cannot be generalized, as they tend to be case specific. A study was therefore conducted to explore the history and reasons for enclosure establishment in Chepareria, a formerly degraded communal rangeland in north-western Kenya. While Vi-Agroforestry Organization accounting for 52.5 % was the main source of knowledge on enclosure establishment; it has now emerged that rangeland enclosures among the Pokot pastoral community existed prior to land management interventions by Vi- Agroforestry. Results indicated that there are three categories of enclosures which were established for boundary demarcation, provide grazing reserves, enable proper land management, facilitate crop cultivation in a pastoral setup and to curb land degradation. The role of self-trigger [accounting for most of the spontaneous enclosures (73.5 %)] indicates the continued establishment and expansion of areas under enclosure management as private land ownership accounting for 51.7 % of enclosure tenure continues to gain momentum in Chepareria. While rangeland enclosures in Chepareria were mainly established for boundary demarcation, to alleviate pasture scarcity and enable proper management of formerly degraded areas; they have facilitated land restoration and rehabilitation by increasing flexibility in land, fodder and livestock management amongst agro-pastoralists in Chepareria over the last three decades. To ensure that rehabilitated areas do not revert to their previously degraded state; technical interventions are needed to allow for a more intensive use of rangeland resources within enclosed areas.

  15. Building Languages

    Science.gov (United States)

    ... Training Manually Coded English (MCE) Natural Gestures Speech Speech Reading (Lip Reading) Even though American Sign Language (ASL) is not a building block, it is sometimes used together with one or more building blocks. Close Information For... Media Policy Makers File Formats Help: How do I view ...

  16. Building Procurement

    DEFF Research Database (Denmark)

    Andersson, Niclas

    2007-01-01

    ‘The procurement of construction work is complex, and a successful outcome frequently elusive’. With this opening phrase of the book, the authors take on the challenging job of explaining the complexity of building procurement. Even though building procurement systems are, and will remain, comple...

  17. [On the question of occurrence and the problem of hygiene rating of fungal air pollution of the environment of residential and public buildings].

    Science.gov (United States)

    Gubernskiĭ, Iu D; Beliaeva, N N; Kalinina, N V; Mel'nikova, A I; Chuprina, O V

    2013-01-01

    Comprehensive sanitary examinations of fungal pollution of the environment of residential and public buildings were performed. There is established the occurrence of sensitization of the population associated with the fungal contamination of the wallings of buildings and presence of viable mold spores in the indoor air environment. Major factors determining the degree of fungal contamination of indoor environments: increasing humidity of indoor air due to leaks and bays, the area of enclosure structures and the temperature factor have been identified.

  18. Climate scenarios in building simulation programmes. First experiences of users; Klimaatscenario's in gebouwsimulatieprogramma's. Eerste gebruikservaringen

    Energy Technology Data Exchange (ETDEWEB)

    Evers, J.; Struck, C.; Hensen, J. [Unit BPS, Technische Universiteit Eindhoven, Eindhoven (Netherlands); Wijsman, A.; Plokker, W. [Vabi Software, Delft (Netherlands); Van Herpen, R. [Adviesburo Nieman, Utrecht (Netherlands)

    2008-11-15

    The Dutch standard NEN 5060:2008 (Hygrothermal characteristics of buildings. Reference climate data) was published early 2008. It includes four new climate datasets intended for different applications, for example in replacement of 'De Bilt 64/65' weather data as a reference year for building simulations. The Royal Dutch MeteoroIogical Institute (KNMI) has compiled four possible scenarios for expected future climate change. The provisional datasets of NEN 5060:2008 and the KNMI scenarios were combined into future climate datasets for use in the building simulation program VA114. The article describes initial experiences in the use of these datasets for assessing future building performance regarding energy consumption and comfort, in a case study of an office building with a peak cooling concept. [Dutch] Begin 2008 is de ontwerp-norm NEN 5060:2008 (Hygrothermische eigenschappen van gebouwen - Referentieklimaatgegevens) gepubliceerd met daarin vier nieuwe klimaatbestanden voor verschillende toepassingen, ter vervanging van bijvoorbeeld 'De Bilt 64/65' als referentiejaar in gebouwsimulaties. Het KNMI heeft vier mogelijke toekomstscenario's opgesteld voor de verwachte klimaalverandering. De klimaatbestanden van NEN 5060:2008 (ontw.) en de KNMI-toekomstscenario's zijn gecombineerd tot toekomstige klimaatbestanden voor gebruik in het gebouwsimulatieprogramma VA114. Aan de hand van een case studie van een kantoorgebouw met een topkoelings-concept worden de eerste ervaringen met het gebruik van deze bestanden beschreven voor het inschatten van de toekomstige gebouwprestaties op het gebied van energiegebruik en comfort.

  19. Building America Case Study: Excavationless Exterior-Side Foundation Insulation for Existing Homes, Minneapolis, Minnesota (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    NorthernSTAR

    2014-09-01

    Building science research supports installing exterior (soil side) foundation insulation as the optimal method to enhance the hygrothermal performance of new homes. With exterior foundation insulation, water management strategies are maximized while insulating the basement space and ensuring a more even temperature at the foundation wall. However, such an approach can be very costly and disruptive when applied to an existing home, requiring deep excavation around the entire house. The NorthernSTAR Building America Partnership team implemented an innovative, minimally invasive foundation insulation upgrade technique on an existing home. The approach consisted of using hydrovac excavation technology combined with a liquid insulating foam. The team was able to excavate a continuous 4" wide by 4' to 5' deep trench around the entire house, 128 linear feet, except for one small part under the stoop that was obstructed with concrete debris. The combination pressure washer and vacuum extraction technology also enabled the elimination of large trenches and soil stockpiles normally produced by backhoe excavation. The resulting trench was filled with liquid insulating foam, which also served as a water-control layer of the assembly. The insulation was brought above grade using a liquid foam/rigid foam hybrid system and terminated at the top of the rim joist. Cost savings over the traditional excavation process ranged from 23% to 50%. The excavationless process could result in even greater savings since replacement of building structures, exterior features, utility meters, and landscaping would be minimal or non-existent in an excavationless process.

  20. Heat dissipation in controlled environment enclosures through the application of water screens

    Science.gov (United States)

    Warrington, I. J.; Halligan, E. A.; Ruby, L. C.; Mcnaughton, K. G.

    1994-01-01

    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 PPF's. 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 is 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., plexiglass) 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 infrared 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 here demonstrate clearly that measurement of PPF alone is not an adequate representation of the radiation environment being used in a controlled environment study. The amounts and proportions of long-wave and short-wave radiation in a plant growth chamber are dependent on lamp type, lamp combination, presence of a thermal barrier, the type of

  1. 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.

  2. Analysis of Magnetic Field Effects on Distributed Heat Sources in a Nanofluid-Filled Enclosure by Natural Convection

    Directory of Open Access Journals (Sweden)

    Alireza Aghaei

    2016-01-01

    Full Text Available This paper studies the effect of magnetic field on the flow field and heat transfer of nanofluid with variable properties in the square enclosure with two arrangements of heat sources. Based upon numerical predictions, the effects of pertinent parameters such as the Rayleigh number (103, 104 and 105, the Hartmann number (0, 25, 50, 75 and 100 and the solid volume fraction (0 to 4% on the flow and temperature fields and the heat transfer performance of the enclosure are examined. For the numerical solution of conservation equations, finite volume method and SIMPLER algorithm was used. The results show that the heat transfer rate influenced by district heat sources and it increases with distributing heat sources on the side walls and it increases with an increase of the Rayleigh number and volume fraction, but decreases with an increase of Hartmann number.

  3. A Place Along the Way: Contextualising Findings from the Iron Age Post Enclosure at Lismullin, Co. Meath, Ireland

    Science.gov (United States)

    Prendergast, Frank

    2015-05-01

    The discovery of an Early Iron Age timber-built post enclosure at Lismullin is arguably the most significant Irish archaeological discovery in recent times. When found, it was immediately evident that a site of major importance and cultural significance had been located. The enclosure complex was constructed from a large number of small wooden posts set out in the form of a three ring structure with an easterly facing avenue accentuated by a four-post entrance feature. This paper summarises the analysis of the geospatial data obtained at the site, and addresses three lines of enquiry relating to the construction method and structural orientation. The cultural significance of the discovery and the findings arising from the data analysis are considered.

  4. Building Data

    Data.gov (United States)

    Town of Cary, North Carolina — Explore real estate information about buildings in the Town of Cary.This file is created by the Town of Cary GIS Group. It contains data from both the Wake, Chatham...

  5. Building Inclusion

    NARCIS (Netherlands)

    Jeanet Kullberg; Isik Kulu-Glasgow

    2009-01-01

    The social inclusion of immigrants and ethnic minorities is a central issue in many European countries. Governments face challenges in ensuring housing for immigrants, delivering public services, promoting neighbourhood coexistence and addressing residential segregation. The Building Inclusion proje

  6. Sustainable Buildings

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Elle, Morten

    The scientific community agrees that: all countries must drastically and rapidly reduce their CO2 emissions and that energy efficient houses play a decisive role in this. The general attitude at the workshop on Sustainable Buildings was that we face large and serious climate change problems...... that need urgent action. The built environment is an obvious area to put effort into because of the large and cost-effective energy saving potential and potential for Renewable Energy-based supply systems for buildings....

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

    Science.gov (United States)

    Maia, Marta Ferreira; Abonuusum, Ayimbire; Lorenz, Lena Maria; Clausen, Peter-Henning; Bauer, Burkhard; Garms, Rolf; Kruppa, Thomas

    2012-01-01

    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.

  8. 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.

  9. Effect of chamber enclosure time on soil respiration flux: A comparison of linear and non-linear flux calculation methods

    Science.gov (United States)

    Kandel, Tanka P.; Lærke, Poul Erik; Elsgaard, Lars

    2016-09-01

    One of the shortcomings of closed chamber methods for soil respiration (SR) measurements is the decreased CO2 diffusion rate from soil to chamber headspace that may occur due to increased chamber CO2 concentrations. This feedback on diffusion rate may lead to underestimation of pre-deployment fluxes by linear regression techniques. Thus, usually the cumulative flux curve becomes downward concave due to the decreased gas diffusion rate. Non-linear models based on biophysical theory usually fit to such curvatures and may reduce the underestimation of fluxes. In this study, we examined the effect of increasing chamber enclosure time on SR flux rates calculated using a linear, an exponential and a revised Hutchinson and Mosier model (HMR). Soil respiration rates were measured with a closed chamber in combination with an infrared gas analyzer. During SR flux measurements the chamber was placed on fixed collars, and CO2 concentration in the chamber headspace were recorded at 1-s intervals for 45 min. Fluxes were measured in different soil types (sandy, sandy loam and organic soils), and for various manipulations (tillage, rain and drought) and soil conditions (temperature and moisture) to obtain a range of fluxes with different shapes of flux curves. The linear method provided more stable flux results during short enclosure times (few min) but underestimated initial fluxes by 15-300% after 45 min deployment time. Non-linear models reduced the underestimation as average underestimation was only about 10% after 45 min for regular flux curves. For irregular flux curves with a rapid increase in CO2 concentration immediately after chamber deployment it was shown that short enclosure times were prone to overestimation of pre-deployment fluxes, but this was mitigated by longer enclosure times (>10-15 min).

  10. Focusing waves at arbitrary locations in a ray-chaotic enclosure using time-reversed synthetic sonas

    Science.gov (United States)

    Xiao, Bo; Antonsen, Thomas M.; Ott, Edward; Anlage, Steven M.

    2016-05-01

    Time-reversal methods are widely used to achieve wave focusing in acoustics and electromagnetics. Past time-reversal experiments typically require that a transmitter be initially present at the target focusing point, which limits the application of this technique. In this paper, we propose a method to focus waves at an arbitrary location inside a complex enclosure using a numerically calculated wave excitation signal. We use a semiclassical ray algorithm to calculate the signal that would be received at a transceiver port resulting from the injection of a short pulse at the desired target location. The time-reversed version of this signal is then injected into the transceiver port, and an approximate reconstruction of the short pulse is created at the target. The quality of the pulse reconstruction is quantified in three different ways, and the values of these metrics are shown to be predicted by the statistics of the scattering parameter | S21|2 between the transceiver and target points in the enclosure over the bandwidth of the pulse. We demonstrate the method experimentally using a flat microwave billiard, and we quantify the reconstruction quality as a function of enclosure loss, port coupling, and other considerations.

  11. Numerical simulation of natural convection in a square enclosure filled with nanofluid using the two-phase Lattice Boltzmann method

    Science.gov (United States)

    2013-01-01

    Considering interaction forces (gravity and buoyancy force, drag force, interaction potential force, and Brownian force) between nanoparticles and a base fluid, a two-phase Lattice Boltzmann model for natural convection of nanofluid is developed in this work. It is applied to investigate the natural convection in a square enclosure (the left wall is kept at a high constant temperature (TH), and the top wall is kept at a low constant temperature (TC)) filled with Al2O3/H2O nanofluid. This model is validated by comparing numerical results with published results, and a satisfactory agreement is shown between them. The effects of different nanoparticle fractions and Rayleigh numbers on natural convection heat transfer of nanofluid are investigated. It is found that the average Nusselt number of the enclosure increases with increasing nanoparticle volume fraction and increases more rapidly at a high Rayleigh number. Also, the effects of forces on nanoparticle volume fraction distribution in the square enclosure are studied in this paper. It is found that the driving force of the temperature difference has the biggest effect on nanoparticle volume fraction distribution. In addition, the effects of interaction forces on flow and heat transfer are investigated. It is found that Brownian force, interaction potential force, and gravity-buoyancy force have positive effects on the enhancement of natural convective heat transfer, while drag force has a negative effect. PMID:23374509

  12. 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.

  13. Use of enclosures with functional vertical space by captive rhesus monkeys (Macaca mulatta) involved in biomedical research.

    Science.gov (United States)

    Clarence, Wendy M; Scott, Jennifer P; Dorris, Michael C; Paré, Martin

    2006-09-01

    We assessed space use by 2 pairs of captive female rhesus monkeys recently transferred into 2 enclosures moderately larger than their former traditional research cages and providing elevated perches at or above human eye level for all monkeys. This new space did not affect the ongoing biomedical research in which these captive monkeys were involved, and we sought to determine whether they used the elevated positions preferentially, as do wild animals. The frequency and duration of visits at each of the 9 distinct regions within these enclosures was calculated during 30-min morning and evening sessions over 20 d. We found that the monkeys frequented all regions of their enclosures in a similar manner during both morning and evening sessions. However, the duration spent at each region varied significantly between morning and evening sessions, with high perches being chosen preferentially in the evenings. Overall, the monkeys spent the majority of their time at elevated positions. These results support the view that access to functional vertical space provides a preferred environment for species- specific behavior and is an option that should be considered by other research facilities.

  14. Convective heat transfer by oscillating flow in an enclosure with non-uniform spatial bottom wall temperature profile

    Science.gov (United States)

    Raheimpour Angeneh, Saeid; Aktas, Murat Kadri

    2016-11-01

    Effects of the acoustic streaming motion on convective heat transfer in a rectangular shallow enclosure with sinusoidal spatial bottom wall temperature distribution are investigated numerically. Acoustic excitation is generated by the periodic vibration of left wall. The top wall of the enclosure is isothermal while the side walls are adiabatic. A FORTRAN code is developed to predict the oscillatory and mean flow fields by considering the compressible form of the Navier -Stokes equation and solved by flux-corrected transport algorithm. In order to validate the results of the simulations, a case with an unheated bottom wall is considered and compared with the existing literature. Applying the sinusoidal temperature profile to the bottom wall provides axial and transverse temperature gradients. In return these gradients strongly affect the flow pattern in the enclosure. Heat transfer depends on the flow structure considerably. This is the first time that the effect of nonzero mean vibrational flow on thermal convection from a surface with sinusoidal temperature profile investigated. Results of this study may lead up to design of new heat removal applications.

  15. Focusing waves at arbitrary locations in a ray-chaotic enclosure using time-reversed synthetic sonas.

    Science.gov (United States)

    Xiao, Bo; Antonsen, Thomas M; Ott, Edward; Anlage, Steven M

    2016-05-01

    Time-reversal methods are widely used to achieve wave focusing in acoustics and electromagnetics. Past time-reversal experiments typically require that a transmitter be initially present at the target focusing point, which limits the application of this technique. In this paper, we propose a method to focus waves at an arbitrary location inside a complex enclosure using a numerically calculated wave excitation signal. We use a semiclassical ray algorithm to calculate the signal that would be received at a transceiver port resulting from the injection of a short pulse at the desired target location. The time-reversed version of this signal is then injected into the transceiver port, and an approximate reconstruction of the short pulse is created at the target. The quality of the pulse reconstruction is quantified in three different ways, and the values of these metrics are shown to be predicted by the statistics of the scattering parameter |S_{21}|^{2} between the transceiver and target points in the enclosure over the bandwidth of the pulse. We demonstrate the method experimentally using a flat microwave billiard, and we quantify the reconstruction quality as a function of enclosure loss, port coupling, and other considerations.

  16. Natural convection heat transfer for a staggered array of heated, horizontal cylinders within a rectangular enclosure

    Energy Technology Data Exchange (ETDEWEB)

    Triplett, C.E.

    1996-12-01

    This thesis presents the results of an experimental investigation of natural convection heat transfer in a staggered array of heated cylinders, oriented horizontally within a rectangular enclosure. The main purpose of this research was to extend the knowledge of heat transfer within enclosed bundles of spent nuclear fuel rods sealed within a shipping or storage container. This research extends Canaan`s investigation of an aligned array of heated cylinders that thermally simulated a boiling water reactor (BWR) spent fuel assembly sealed within a shipping or storage cask. The results are presented in terms of piecewise Nusselt-Rayleigh number correlations of the form Nu = C(Ra){sup n}, where C and n are constants. Correlations are presented both for individual rods within the array and for the array as a whole. The correlations are based only on the convective component of the heat transfer. The radiative component was calculated with a finite-element code that used measured surface temperatures, rod array geometry, and measured surface emissivities as inputs. The correlation results are compared to Canaan`s aligned array results and to other studies of natural convection in horizontal tube arrays.

  17. Commissioning of experimental enclosures (Hutches) at the Advanced Photon Source - A to Z ALARA.

    Energy Technology Data Exchange (ETDEWEB)

    Vacca, J.; Job, P. K.; Rauchas, A.; Justus, A.; Veluri, V. R.

    2000-11-01

    The Advanced Photon Source (APS), 7 GeV electron Storage Ring at the Argonne National Laboratory is designed to be a major national user facility providing high-brilliance x-ray beams. Figure 1 shows a plan view of the APS. At completion, APS will have 35 bending magnet (BM) beamlines and 35 insertion device (ID) beamlines. A typical x-ray beamline at APS comprises of a front end (FE) that confines the beam; a first optics enclosure (FOE) which houses optics to filter and monochromatize the beam; and beam transports, additional optics, and the experiment stations. Figure 2 shows a section of the storage ring with the layout of the ID and BM beamlines and typical experiment stations. The first x-ray beam was delivered to an experiment station in 1995. Ever since, to date, over 120 experimental stations (hutches) have been commissioned and are receiving intense x-ray beams of varying energies for various experiments. This paper describes in some detail the steps involved in the process of commissioning experimental stations and the implementation of the ALARA at each step.

  18. Low eddy current RF shielding enclosure designs for 3T MR applications.

    Science.gov (United States)

    Lee, Brian J; Watkins, Ronald D; Chang, Chen-Ming; Levin, Craig S

    2017-06-06

    Magnetic resonance-compatible medical devices operate within the MR environment while benefitting from the superior anatomic information of MRI. Avoiding electromagnetic interference between such instrumentation and the MR system is crucial. In this work, various shielding configurations for positron emission tomography (PET) detectors were studied and analyzed regarding radiofrequency (RF) shielding effectiveness and gradient-induced eddy current performances. However, the results of this work apply to shielding considerations for any MR-compatible devices. Six shielding enclosure configurations with various thicknesses, patterns, and materials were designed: solid and segmented copper, phosphor bronze mesh (PBM), and carbon fiber composite (CFC). A series of tests was performed on RF shielding effectiveness and the gradient-induced eddy current. For the shielding effectiveness, the solid copper with various thickness and PBM configurations yield significantly better shielding effectiveness (>15 dB) compared with CFC and segmented configurations. For the gradient-induced eddy current performance, the solid copper shielding configurations with different thicknesses showed significantly worse results, up to a factor of 3.89 dB, compared with the segmented copper, PBM, and the CFC configurations. We evaluated the RF shielding effectiveness and the gradient-induced eddy current artifacts of several shielding designs, and only the PBM showed positive outcomes for both aspects. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  19. Standard Guide for Selection of Test Methods for Interlayer Materials for Aerospace Transparent Enclosures

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This guide summarizes the standard test methods available for determining physical and mechanical characteristics of interlayer materials used in multi-ply aerospace transparent enclosures. 1.2 Interlayer materials are used to laminate glass-to-glass, glass-to-plastic, and plastic-to-plastic. Interlayer materials are basically transparent adhesives with high-quality optical properties. They can also serve as an energy absorbing medium, a fail-safe membrane to contain cockpit pressure and to prevent entry of impact debris; a strain insulator to accommodate different thermal expansion rates of members being laminated and as an adherent to prevent spalling of inner surface ply material fragments. The relative importance of an interlayer characteristic will be a function of the prime use it serves in its particular application. 1.3 This guide, as a summary of various methods in Section 2, is intended to facilitate the selection of tests that can be applied to interlayer materials. 1.4 The test methods list...

  20. Numerical simulation of MHD free convection flow in a differentially heated square enclosure with tilted obstacle

    Science.gov (United States)

    Ali, M. M.; Alim, M. A.; Maleque, M. A.; Ahmed, Syed Sabbir

    2017-06-01

    A numerical study has been carried out to analyze the flow and heat transfer characteristics due to the effects of magnetohydrodynamic free convection flow in a differentially heated enclosure having a hot tilted square block. The vertical and horizontal walls of the cavity are non-uniformly heated while the walls of the tilted block are uniformly heated. The basic partial differential equations of the physical problem are solved numerically using finite element technique along with Galerkin's weighted residual simulation. Calculations have been performed for different values of buoyancy parameter (102 ≤ Ra ≤ 105) and magnetic field parameter (0 ≤ Ha ≤ 60) and obtained results are illustrated in terms of streamlines, isotherms, average Nusselt number and average temperature. The results show that the flow pattern and temperature distributions affected noticeably for the effect of aforementioned parameters. In addition, an increase in average Nusselt number is found for the whole range of Rayleigh number and average temperature decreased for increasing Rayleigh number. Comparison between the obtained results and the previously published results on the basis of special case is a good agreement.

  1. Thermal and solutal convection with conduction effects inside a rectangular enclosure

    Science.gov (United States)

    Mennetrier, Christophe; Duval, Walter M. B.

    1991-01-01

    We numerically investigate the effects of various boundary conditions on the flow field characteristics of the physical vapor transport process. We use a prescribed temperature profile as boundary condition on the enclosure walls, and we consider parametric variations applicable to ground-based and space microgravity conditions. For ground-based applications, density gradients in the fluid phase generate buoyancy-driven convection which in turn disrupts the uniformity of the mass flux at the interface depending on the orientation. Heat conduction in the crystal can affect the fluid flow near the interface of the crystal. When considering isothermal source and sink at the interfaces, we observe a diffusive mode and three modes (i.e., thermal, solutal, and thermo-solutal). The convective modes show opposing flow field trends between thermal and solutal convection; theoretically, these trends can be used to achieve a uniform mass flux near the crystal. However, under the physical conditions chosen, the mathematical condition necessary for uniform mass flux cannot be satisfied because of thermodynamic restrictions. When a longitudinal thermal gradient is prescribed on the boundary of the crystal, a non-uniform interface temperature results, which induces a symmetrical fluid flow near the interface for the vertical case. For space microgravity applications, we show that the flow field is dominated by the Stefan wind and a uniform mass flux results at the interface.

  2. Nanoscale imaging of whole cells using a liquid enclosure and a scanning transmission electron microscope.

    Directory of Open Access Journals (Sweden)

    Diana B Peckys

    Full Text Available Nanoscale imaging techniques are needed to investigate cellular function at the level of individual proteins and to study the interaction of nanomaterials with biological systems. We imaged whole fixed cells in liquid state with a scanning transmission electron microscope (STEM using a micrometer-sized liquid enclosure with electron transparent windows providing a wet specimen environment. Wet-STEM images were obtained of fixed E. coli bacteria labeled with gold nanoparticles attached to surface membrane proteins. Mammalian cells (COS7 were incubated with gold-tagged epidermal growth factor and fixed. STEM imaging of these cells resulted in a resolution of 3 nm for the gold nanoparticles. The wet-STEM method has several advantages over conventional imaging techniques. Most important is the capability to image whole fixed cells in a wet environment with nanometer resolution, which can be used, e.g., to map individual protein distributions in/on whole cells. The sample preparation is compatible with that used for fluorescent microscopy on fixed cells for experiments involving nanoparticles. Thirdly, the system is rather simple and involves only minimal new equipment in an electron microscopy (EM laboratory.

  3. The use of an active controlled enclosure to attenuate sound radiation from a heavy radiator

    Science.gov (United States)

    Sun, Yao; Yang, Tiejun; Zhu, Minggang; Pan, Jie

    2017-03-01

    Active structural acoustical control usually experiences difficulty in the control of heavy sources or sources where direct applications of control forces are not practical. To overcome this difficulty, an active controlled enclosure, which forms a cavity with both flexible and open boundary, is employed. This configuration permits indirect implementation of active control in which the control inputs can be applied to subsidiary structures other than the sources. To determine the control effectiveness of the configuration, the vibro-acoustic behavior of the system, which consists of a top plate with an open, a sound cavity and a source panel, is investigated in this paper. A complete mathematical model of the system is formulated involving modified Fourier series formulations and the governing equations are solved using the Rayleigh-Ritz method. The coupling mechanisms of a partly opened cavity and a plate are analysed in terms of modal responses and directivity patterns. Furthermore, to attenuate sound power radiated from both the top panel and the open, two strategies are studied: minimizing the total radiated power and the cancellation of volume velocity. Moreover, three control configurations are compared, using a point force on the control panel (structural control), using a sound source in the cavity (acoustical control) and applying hybrid structural-acoustical control. In addition, the effects of boundary condition of the control panel on the sound radiation and control performance are discussed.

  4. Laminar Natural Convection of Newtonian and Non – Newtonian Fluids Inside Triangular Enclosure

    Directory of Open Access Journals (Sweden)

    Ala?a Abbas Muhadi

    2007-01-01

    Full Text Available In the present work, steady two – dimensional laminar natural convection heat transfer of Newtonian and non-Newtonian fluids inside isosceles triangular enclosure has been analyzed numerically for a wide range of the modified Rayleigh numbers of (103 ≤ Ra ≤ 105, with non-dimensional parameter (NE of Prandtl – Eyring model ranging from (0 to 10, and modified Prandtl number take in the range (Pr* =1,10, and 100. Two types of boundary conditions have been considered. The first, when the inclined walls are heated with different uniform temperatures and the lower wall is insulated. The second, when the bottom wall is heated by applying a uniform heat flux while the inclined walls at the constant cold temperature. Also, the non-Newtonian fluids under consideration were assumed to obey the Prandtl – Eyring model..The results are presented in terms of isotherms and streamlines to show the behavior of the fluid flow and temperature fields. In addition, some graphics are presented the relation between average Nusselt number and the various parameters. The results show the effect of non – dimensional parameter (NE on the velocity and temperature profiles. They also show that the average Nusselt number is a strong function of modified Rayleigh number, modified Prandtl number, non-dimensional parameter, and the boundary conditions. Four different correlations have been made to show the dependence of the average Nusselt number on the non-dimensional parameter, the modified Rayleigh and Prandtl numbers.

  5. MHD Natural Convection in a Square Enclosure using Nanofluid with the Influence of Thermal Boundary Conditions

    Directory of Open Access Journals (Sweden)

    M.A Mansour

    2016-01-01

    Full Text Available Numerical investigation for heat transfer with steady MHD natural convection cooling of a localized heat source at the bottom wall of an enclosure filled with nanofluids subjected to changeable thermal boundary conditions at the sidewalls has been studied in the a presence of inclined magnetic field. Finite difference method was employed to solve the dimensionless governing equations of the problem. The effects of governing parameters, namely, Hartmann number, solid volume fraction, the different values of the heat source length and the different locations of the heat source on the streamlines and isotherms contours as well as maximum temperature, Nusselt number and average Nusselt number along the heat source were considered. The present results are validated by favorable comparisons with previously published results. The results of the problem are presented in graphical and tabular forms and discussed. It is found that an increase in the Hartmann number results in a clear reduction in the rate of heat transfer; however, the increase in Rayleigh number enhances the nanofluid flow and heat transfer rate.

  6. Computational Fluid Dynamics (CFD) Analysis Of Optical Payload For Lasercomm Science (OPALS) sealed enclosure module

    Science.gov (United States)

    Anderson, Kevin R.; Zayas, Daniel; Turner, Daniel

    2012-01-01

    Computational Fluid Dynamics (CFD) using the commercial CFD package CFDesign has been performed at NASA Jet Propulsion Laboratory (JPL) California Institute of Technology (Caltech) in support of the Phaeton Early Career Hire Program's Optical Payload for Lasercomm Science (OPALS) mission. The OPALS project is one which involves an International Space Station payload that will be using forced convection cooling in a hermetically sealed enclosure at 1 atm of air to cool "off-the-shelf" vendor electronics. The CFD analysis was used to characterize the thermal and fluid flow environment within a complicated labyrinth of electronics boards, fans, instrumentation, harnessing, ductwork and heat exchanger fins. The paradigm of iteratively using CAD/CAE tools and CFD was followed in order to determine the optimum flow geometry and heat sink configuration to yield operational convective film coefficients and temperature survivability limits for the electronics payload. Results from this current CFD analysis and correlation of the CFD model against thermal test data will be presented. Lessons learned and coupled thermal / flow modeling strategies will be shared in this paper.

  7. REVIEW ON POROUS AND NON-POROUS FLAT PLATE AIR COLLECTOR WITH MIRROR ENCLOSURE

    Directory of Open Access Journals (Sweden)

    M. PRADHAPRAJ,

    2010-09-01

    Full Text Available In solar air heater, flat plat collectors are the best heat transferring devices. But the effectiveness of these collectorsis very low because of lack of technology. Solar assisted heated air is successfully used for drying applications and space heating under controlled conditions. From the solar flat plate air heater the hot air is transferred to a conventional dryer or to the combined heater and drying chamber directly. Hence, solar assisted air heaters arecheaper and reliable. The important factors affecting these systems are the solar radiation, mechanical loading, temperature and leakage. The air heater efficiency depends on the design of the system as well as the construction materials and the assembly. The solar air heating systems has acceptable life span of 15 to 20 years. The addition ofside mirror enclosures is to increase the amount of solar radiation absorption at the collector plate so that the collector increases the yield and operate in a higher temperature range. Therefore with the addition of side mirrors one can able to maximize the output of fixed flat plate collectors. A flat plate air collector will be more efficient if it is made up of porous medium when comparing it with the non porous collectors according to the study. In this paper, the performances of porous and non-porous absorber plates are discussed. Also the possible methods of finding out air leakages and the methodology adopted for the performance and efficiency calculations are also discussed.

  8. Cold Climate Foundation Retrofit Energy Savings: The Simulated Energy and Experimental Hygrothermal Performance of Cold Climate Foundation Wall Insulation Retrofit Measures -- Phase I, Energy Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, L. F.; Steigauf, B.

    2013-04-01

    A split simulation whole building energy/3-dimensional earth contact model (termed the BUFETS/EnergyPlus Model or BEM) capable of modeling the full range of foundation systems found in the target retrofit housing stock has been extensively tested. These foundation systems that include abovegrade foundation walls, diabatic floors or slabs as well as lookout or walkout walls, currently cannot be modeled within BEopt.

  9. Cold Climate Foundation Retrofit Energy Savings. The Simulated Energy and Experimental Hygrothermal Performance of Cold Climate Foundation Wall Insulation Retrofit Measures -- Phase I, Energy Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Louise F. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States); Steigauf, Brianna [NorthernSTAR Building America Partnership, Minneapolis, MN (United States)

    2013-04-01

    A split simulation whole building energy / 3-dimensional earth contact model (termed the BUFETS/EnergyPlus Model or BEM) capable of modeling the full range of foundation systems found in the target retrofit housing stock has been extensively tested. These foundation systems that include abovegrade foundation walls, diabatic floors or slabs as well as lookout or walkout walls, currently cannot be modeled within BEopt.

  10. Our Buildings, Ourselves.

    Science.gov (United States)

    Roodman, David Malin; Lenssen, Nicholas

    1994-01-01

    Reviews in detail environmental impacts associated with buildings. Discusses building construction, internal environments, building life spans, building materials, protection from climate, and amenities. (LZ)

  11. Numerical simulation of {sup 222}RN exhalation from phosphogypsum building blocks and accumulation inside a closed chamber

    Energy Technology Data Exchange (ETDEWEB)

    Rabi Junior, Jose A. [Sao Paulo Univ., Pirassununga, SP (Brazil). Faculdade de Zootecnia e Engenharia de Alimentos]. E-mail: jrabi@fzea.usp.br; Silva, Nivaldo C. da [Pontificia Univ. Catolica de Minas Gerais, Pocos de Caldas, MG (Brazil)]|[Comissao Nacional de Energia Nuclear (CNEN), Pocos de Caldas, MG (Brazil). Laboratorio]. E-mail: ncsilva@pucpcaldas.br; ncsilva@cnen.gov.br

    2005-07-01

    Zero-order models for {sup 222}Rn exhalation from phosphogypsum-bearing building materials and its transient indoor accumulation assume uniform distribution inside the enclosure. Conversely, this paper numerically simulates a transient two-dimensional {sup 222}Rn accumulation in a test chamber that contains a phosphogypsum board at one wall. Results show that above hypothesis might be oversimplified when spatial dependence is considered. (author)

  12. Identification of ancient paths within the Late Bronze Age enclosure Corneşti-Iarcuri, western Romania

    Science.gov (United States)

    Nykamp, Moritz; Heeb, Bernhard S.; Hoelzmann, Philipp; Knitter, Daniel; Krause, Jan; Krause, Rüdiger; Szentmiklosi, Alexandru; Schütt, Brigitta

    2016-04-01

    This study applies a landscape archaeological approach, combining geoscientific and archaeological data, to shed light into the Holocene landscape development in the environs of the Late Bronze Age enclosure of Corneşti-Iarcuri, Romania. Corneşti-Iarcuri is located at the eastern edge of the Great Hungarian Plain and represents with its four earth-filled wooden ramparts the largest known prehistoric enclosure in Europe. Late Bronze Age settlements are documented for the two innermost enclosures. However, the settlement history in its environs started already in the Copper Age. The aims of this study are i) to link hydro-morphological relief anomalies to evidences of settlement occurrence and ii) to document the variations of Holocene geomorphic activity and stability in a selected sub-catchment. The spatio-temporal relation between unnaturally bending tributaries and settled areas is uncovered and the involved formation processes are discussed. The morphometric analyses of the tributaries in the built-up area of Iarcuri show a clear tendency: unnaturally bending tributaries most often occur in the central valley and tend to cluster in the central part between the two innermost enclosures. By comparison of the locations of the strongly bending tributaries and the locations of the most densely settled areas it appears that both are related. It is well known that such linear features form in relation to settlements as a consequence of repeated passage of humans. Due to soil compaction along regular footpaths and the resulting reduced infiltration capacity gully erosion tends to occur forming hollow ways. Usually these hollow ways form contemporaneously with or subsequent to the occupation period of the site. As a consequence alluvial fans form at the outlet of the tributaries documenting former settlement and geomorphic activities. A sediment core obtained from the alluvial fan dumped by the tributary sourcing in the densely settled southern part of enclosure II

  13. Competence Building

    DEFF Research Database (Denmark)

    Borrás, Susana; Edquist, Charles

    on the one hand, and the real world of innovation policy-making on the other, typically not speaking to each other. With this purpose in mind, this paper discusses the role of competences and competence-building in the innovation process from a perspective of innovation systems; it examines how governments...... and public agencies in different countries and different times have actually approached the issue of building, maintaining and using competences in their innovation systems; it examines what are the critical and most important issues at stake from the point of view of innovation policy, looking particularly...

  14. Effect of water-ice phase change on thermal performance of building materials

    Science.gov (United States)

    Kočí, Václav; Černý, Robert

    2016-07-01

    The effect of water ice-phase change on thermal performance of integrated building material is investigated in this paper. As a characteristic construction, simple external wall made of aerated autoclaved concrete was assumed which was exposed to dynamic climatic condition of Šerák, Czech Republic. The computational modelling of hygrothermal performance was carried out using computer codes HEMOT and SIFEL that work on the basis of finite element method. The effect of phase change was taken into account by fixed-domain method, when experimentally determined effective specific heat capacity was used as a material parameter. It comprises also the effect of heat consumption and heat release that accompany the water-ice phase change. Comparing to the results with specific heat capacity, the effect of phase change on thermal performance could be quantified. The results showed that temperature fields can differ more than 6 °C. Additionally, the amount energy transported through the wall may be higher up to 4 %. This confirmed, that the effect water-ice phase change should be included in all the relevant energy calculations.

  15. Fate of the insecticide lambda-cyhalothrin in ditch enclosures differing in vegetation density.

    Science.gov (United States)

    Leistra, Minze; Zweers, Anton J; Warinton, Jacqui S; Crum, Steven J H; Hand, Laurence H; Beltman, Wim H J; Maund, Stephen J

    2004-01-01

    Use of the insecticide lambda-cyhalothrin in agriculture may result in the contamination of water bodies, for example by spray drift. Therefore, the possible exposure of aquatic organisms to this insecticide needs to be evaluated. The exposure of the organisms may be reduced by the strong sorption of the insecticide to organic materials and its susceptibility to hydrolysis at the high pH values in the natural range. In experiments done in May and August, formulated lambda-cyhalothrin was mixed with the water body of enclosures in experimental ditches containing a bottom layer and macrophytes (at different densities) or phytoplankton. Concentrations of lambda-cyhalothrin in the water body and in the sediment layer, and contents in the plant compartment, were measured by gas-liquid chromatography at various times up to 1 week after application. Various water quality parameters were also measured. Concentrations of lambda-cyhalothrin decreased rapidly in the water column: 1 day after application, 24-40% of the dose remained in the water, and by 3 days it had declined to 1.8-6.5%. At the highest plant density, lambda-cyhalothrin residue in the plant compartment reached a maximum of 50% of the dose after 1 day; at intermediate and low plant densities, this maximum was only 3-11% of the dose (after 1-2 days). The percentage of the insecticide in the ditch sediment was 12% or less of the dose and tended to be lower at higher plant densities. Alkaline hydrolysis in the water near the surface of macrophytes and phytoplankton is considered to be the main dissipation process for lambda-cyhalothrin.

  16. Engaging creative communities in an industrial city setting: A question of enclosure

    Directory of Open Access Journals (Sweden)

    Chris Gibson

    2012-08-01

    difficulties of the research methodologies adopted. Keywords: Cultural industries, engagement, enclosure, community, vernacular creativity, Wollongong, Australia

  17. Chryseobacterium chengduensis sp. nov. isolated from the air of captive giant panda enclosures in Chengdu, China.

    Science.gov (United States)

    Wen, Cai-Fang; Xi, Li-Xin; Zhao, Shan; Hao, Zhong-Xiang; Luo, Lu; Liao, Hong; Chen, Zhen-Rong; She, Rong; Han, Guo-Quan; Cao, San-Jie; Wu, Rui; Yan, Qi-Gui; Hou, Rong

    2016-08-01

    A Gram-negative, aerobic, non-motile, rod-shaped bacterial strain, designated 25-1(T), was isolated from the air inside giant panda enclosures at the Chengdu Research Base of Giant Panda Breeding, China. Strain 25-1(T) grew optimally at pH 7.0-8.0, at 28-30 °C and in the presence of NaCl concentrations from 0.0% to 0.5 %. 16S rRNA gene sequence analysis indicated that strain 25-1(T) belongs to the genus Chryseobacterium within the family Flavobacteriaceae and is related most closely to C. carnis G81(T) (96.4% similarity), C. lathyri RBA2-6(T) (95.8% similarity), and C. zeae JM1085(T) (95.8% similarity). Its genomic DNA G+C molar composition was 36.2%. The major cellular fatty acids were iso-C15:0 (44.0%), iso-C17:0 3OH (19.8%) and C16:1 ω7c/16:1 ω6c (12.7%). The only isoprenoid quinone was menaquinone 6 (MK-6). The major polar lipids were phosphatidylethanolamine, two unidentified amino lipids and two unidentified lipids. The DNA-DNA relatedness between strain 25-1(T) and C. lathyri RBA2-6(T) was 38%. Phenotypic, genotypic, and phylogenetic characteristics indicated that strain 25-1(T) is a novel member of the genus Chryseobacterium, for which the name C. chengduensis sp. nov. is proposed. The type strain is 25-1(T) (CCTCC AB2015133(T)=DSM 100396(T)).

  18. Exposure of juvenile green frogs (Lithobates clamitans) in littoral enclosures to a glyphosate-based herbicide.

    Science.gov (United States)

    Edge, Christopher B; Gahl, Megan K; Pauli, Bruce D; Thompson, Dean G; Houlahan, Jeff E

    2011-07-01

    The majority of studies on the toxicity of glyphosate-based herbicides to amphibians have focused on larval life stages exposed in aqueous media. However, adult and juvenile amphibians may also be exposed directly or indirectly to herbicides. The potential for such exposures is of particular interest in the littoral zone surrounding wetlands as this is preferred habitat for many amphibian species. Moreover, it may be argued that potential herbicide effects on juvenile or adult amphibians could have comparatively greater influence on overall recruitment, reproductive potential and thus stability of local populations than effects on larvae. In this experiment, juvenile green frogs (Lithobates clamitans) were exposed to two concentrations (2.16 and 4.27 kg a.e./ha) of a glyphosate-based herbicide formulation (VisionMax®), which were based on typical application scenarios in Canadian forestry. The experimental design employed frogs inhabiting in situ enclosures established at the edge of small naturalized wetlands that were split in half using an impermeable plastic barrier. When analyzed using nominal target application rates, exposure to the glyphosate-based herbicide had no significant effect on survival, body condition, liver somatic index or the observed rate of Batrachochytrium dendrobatidis infection. However, there were marginal trends in both ANOVA analysis and post-hoc regressions regarding B. dendrobatidis infection rates and liver somatic index in relation to measured exposure estimates. Results from this study highlight the importance of field research and the need to include multiple endpoints when examining potential effects of a contaminant on non-target organisms. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Numerical investigation of natural convection in two enclosures separated by anisotropic solid wall

    KAUST Repository

    Salama, Amgad

    2014-10-28

    Purpose: The problem of natural convection in two cavities separated by an anisotropic central solid wall is considered numerically. When the thermal conductivity of the central wall is anisotropic, heat flux and temperature gradient vectors are no longer coincidence. This apparently has interesting influences on the heat and fluid flow patterns in this system. The paper aims to discuss these issues.Design/methodology/approach: In this work, several flow patterns have been investigated covering a wide range of Rayleigh number up to 108. Several thermal conductivity anisotropy scenarios of the central wall have been investigated including 0, 30, 60, 120 and 1501 principal anisotropy directions. The governing equations have been solved using control volume approach.Findings: Probably the most intriguing is that, for some anisotropy scenarios it is found that the temperature at the same elevation at the side of the central wall which is closer to the colder wall is higher than that at the side closer to the hot wall. Apparently this defies intuition which suggests the reverse to have happened. However, this behavior may be explained in light of the effect of anisotropy. Furthermore, the patterns of streamlines and temperature fields in the two enclosures also changes as a consequence of the change of the central wall temperatures for the different anisotropy scenarios.Originality/value: This work discusses a very interesting topic related to heat energy exchange among two compartments when the separating wall is anisotropic. In some anisotropy scenarios, this leads to more uniform distribution of Nusselt number than the case when the wall is isotropic. Interesting patterns of natural convection is investigated.

  20. Building Sandcastles

    DEFF Research Database (Denmark)

    Jensen, Steffen Moltrup Ernø; Korsgaard, Steffen; Shumar, Wes

    of entrepreneurship education. Our theoretical and methodological approach builds on Actor-Network Theory. The empirical settings of our study consist of two entrepreneurship courses which differ in terms of temporal extension and physical setting. Data is collected using observation and interview techniques. Our...

  1. Building economics

    DEFF Research Database (Denmark)

    Pedersen, D.O.(red.)

    Publikationen er på engelsk. Den omfatter alle indlæg på det fjerde internationale symposium om byggeøkonomi, der blev arrangeret af SBI for det internationale byggeforskningsråd CIB. De fem bind omhandler: Methods of Economic Evaluation, Design Optimization, Ressource Utilization, The Building...

  2. Building Partnerships.

    Science.gov (United States)

    Kisner, Mary J.; And Others

    1997-01-01

    Defines school-business partnerships and reviews changes in such partnerships over the past 25 years. Provides steps to building effective partnerships for school-to-work activities: review the school's mission; select partners that will bring strength to the relationship; set clearly defined, realistic goals; maintain the partnership; and…

  3. Sustainable Buildings

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Elle, Morten

    The scientific community agrees that: all countries must drastically and rapidly reduce their CO2 emissions and that energy efficient houses play a decisive role in this. The general attitude at the workshop on Sustainable Buildings was that we face large and serious climate change problems...

  4. Building Procurement

    DEFF Research Database (Denmark)

    Andersson, Niclas

    2007-01-01

    despite this excellent book, the knowledge, expertise, well-articulated argument and collection of recent research efforts that are provided by the three authors will help to make project success less elusive. The book constitutes a thorough and comprehensive investigation of building procurement, which......, which gives the book a challenging contribution to the existing body of knowledge....

  5. Building Partnerships.

    Science.gov (United States)

    Kisner, Mary J.; And Others

    1997-01-01

    Defines school-business partnerships and reviews changes in such partnerships over the past 25 years. Provides steps to building effective partnerships for school-to-work activities: review the school's mission; select partners that will bring strength to the relationship; set clearly defined, realistic goals; maintain the partnership; and…

  6. Existing buildings

    DEFF Research Database (Denmark)

    Gram-Hanssen, Kirsten

    2014-01-01

    their homes. These policy measures include building regulations, energy tax and different types of incentives and information dissemination. The conclusion calls for new and innovative policy measures to cope with the realities of renovations of owner-occupied houses and how energy efficiency improvement...

  7. Design and Analysis of GIS Bus Enclosure Considering Internal Arcing%内部故障电弧下GIS母线壳体的分析及设计

    Institute of Scientific and Technical Information of China (English)

    宫瑞磊; 肖凌风

    2013-01-01

    To ensure that an SF6 GIS bus enclosure does not explode as it has been burnt out or the short-circuit current has been cut-off during internal arcing, a construction design of SF6 GIS bus enclosure was completed according to an empirical formula, and the mechanical strength of the enclosure was computed based on the structural module in the software ANSYS. Moreover, the strength of the enclosure was verified through 2.8 MPa hydraulic pressure test to demonstrate the validity of the design. In addition, Considering the extending burnt-out time of the enclosure due to moving effect of arc in the metal enclosure, the capability of the GIS bus to withstand internal arc was evaluated in this condition. Result reveals that the designed SF6 GIS bus enclosure can meet the standards.%为验证GIS母线壳体在发生内部故障电弧时,壳体烧穿或短路电流被开断而不会发生爆炸,笔者依据经验公式完成了GIS母线筒的结构设计,并通过ANSYS结构模块对母线筒的强度进行了计算验证,同时通过2.8 MPa水压试验完成了对母线筒强度的校核,验证了设计和理论计算分析的可靠性.另外,考虑到母线筒内电弧的运动效应,由此引起的壳体烧穿时间加长,计算分析了此种情况下GIS母线耐内部故障电弧的能力.分析的结果表明,设计的母线壳体能够满足标准要求.

  8. Building Bridges

    DEFF Research Database (Denmark)

    The report Building Bridges adresses the questions why, how and for whom academic audience research has public value, from the different points of view of the four working groups in the COST Action IS0906 Transforming Audiences, Transforming Societies – “New Media Genres, Media Literacy and Trust...... in the Media”, “Audience Interactivity and Participation”, “The Role of Media and ICT Use for Evolving Social Relationships” and “Audience Transformations and Social Integration”. Building Bridges is the result of an ongoing dialogue between the Action and non-academic stakeholders in the field of audience...... Belgrade), Leo Pekkala (Finnish Centre for Media Education and Audiovisual Media/MEKU), Julie Uldam (Network on Civic Engagement and Social Innovation) and Gabriella Velics (Community Media Forum Europe)....

  9. Building Letters

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Cabinet是种十分吸引人却很简单的衬线字体,是由一名匿名字体设计师专门为Building Letters最新的资金筹集活动所设计的。这个Building Letters包中包含一个CDROM,有32种字体,以及一本专门设计的杂志和两张由Eboy和Emigre所设计的海报。字体光盘样例是由世界顶级的字体设计师们设计的.

  10. 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.

  11. 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.

  12. Building economics

    DEFF Research Database (Denmark)

    Pedersen, D.O.(red.)

    Publikationen er på engelsk. Den omfatter alle indlæg på det fjerde internationale symposium om byggeøkonomi, der blev arrangeret af SBI for det internationale byggeforskningsråd CIB. De fem bind omhandler: Methods of Economic Evaluation, Design Optimization, Ressource Utilization, The Building...... Market og Economics and Technological Forecasting in Construction. Et indledende bind bringer statusrapporter for de fem forskningsområder, og det sidste bind sammenfatter debatten på symposiet....

  13. 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

  14. Prevalence of Hepatitis E Virus in Populations of Wild Animals in Comparison with Animals Bred in Game Enclosures.

    Science.gov (United States)

    Kubankova, Monika; Kralik, Petr; Lamka, Jiri; Zakovcik, Vladimir; Dolanský, Marek; Vasickova, Petra

    2015-03-15

    Hepatitis E virus (HEV) is now accepted as a zoonotic virus, and domestic pigs, wild boars and deer are recognised as natural reservoirs of the pathogen. In this study, 762 animals (wild boars, fallow deer, red deer, sika deer, roe deer and mouflons) originating from the wild and from game enclosures were tested for the presence of HEV RNA by qRT-PCR. HEV RNA was detected in wild boars (96/450), red deer (2/169), roe deer (1/30) and mouflons (5/39). The sequence relationship between HEV isolates from wild boars and domestic pigs or humans indicate a circulation of HEV in the Czech Republic.

  15. Evaluation of Crawlspace Retrofits in Multifamily Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, A.

    2014-09-01

    In 2011 and early 2012, Building Science Corporation (BSC) collaborated with Innova Services Corporation on a multifamily community unvented crawlspace retrofit project at Oakwood Gardens in Lansdale, Pennsylvania. BSC provided design consulting services and pre- and post-retrofit evaluation, testing, and data monitoring. The existing condition was a vented crawlspace with an uninsulated floor between the crawlspace and the dwelling units above. The crawlspace was therefore a critically weak link in the building enclosure and was ripe for improvement. Saving energy was the primary interest and goal, but the greatest challenge in this unvented crawlspace retrofit project was working through a crawlspace bulk water intrusion problem caused by inadequate site drainage, window well drainage, foundation wall drainage, and a rising water table during rainy periods. While the unvented crawlspace retrofit was effective in reducing heat loss, and the majority of the bulk water drainage problems had been resolved, the important finding was that some of the wood joists embedded in masonry pockets behind the brick veneer were showing signs of moisture damage.

  16. Building information models for astronomy projects

    Science.gov (United States)

    Ariño, Javier; Murga, Gaizka; Campo, Ramón; Eletxigerra, Iñigo; Ampuero, Pedro

    2012-09-01

    A Building Information Model is a digital representation of physical and functional characteristics of a building. BIMs represent the geometrical characteristics of the Building, but also properties like bills of quantities, definition of COTS components, status of material in the different stages of the project, project economic data, etc. The BIM methodology, which is well established in the Architecture Engineering and Construction (AEC) domain for conventional buildings, has been brought one step forward in its application for Astronomical/Scientific facilities. In these facilities steel/concrete structures have high dynamic and seismic requirements, M&E installations are complex and there is a large amount of special equipment and mechanisms involved as a fundamental part of the facility. The detail design definition is typically implemented by different design teams in specialized design software packages. In order to allow the coordinated work of different engineering teams, the overall model, and its associated engineering database, is progressively integrated using a coordination and roaming software which can be used before starting construction phase for checking interferences, planning the construction sequence, studying maintenance operation, reporting to the project office, etc. This integrated design & construction approach will allow to efficiently plan construction sequence (4D). This is a powerful tool to study and analyze in detail alternative construction sequences and ideally coordinate the work of different construction teams. In addition engineering, construction and operational database can be linked to the virtual model (6D), what gives to the end users a invaluable tool for the lifecycle management, as all the facility information can be easily accessed, added or replaced. This paper presents the BIM methodology as implemented by IDOM with the E-ELT and ATST Enclosures as application examples.

  17. MYCELIUM BUILDING

    OpenAIRE

    Jondelius, Olof

    2015-01-01

    This work is looking in to what possibilites and restrictions comes with using mycelium as a building material for a small house. It includes reasoning around solutions for some of the problems and presenting some ideas of how to use some of the materials properties in your favor. A general background of why we need to start look in to alternative materials for all petroleum materials are presented. Det här arbetet har varit inriktat på att se vilka möjligheter samt begränsningar det skul...

  18. Building sustainability

    CSIR Research Space (South Africa)

    Mass Media

    2007-11-01

    Full Text Available establishment of its platform. Van Wyk believes that South Africa faces other challenges when it comes to sustainable building. “You can’t separate the process from the product,” he says. “South Africa still has to learn a lot and has to make many... stakeholders and implemented at an early stage. By G uy O lde nk ott e Bu idl ing Af ric aa rc hiv es Bu idl ing Af ric aa rc hiv es Perfect blend November 2007 jFM BUSINESS, RETAIL & LEISURE FACILITIES6 During the FM Expo...

  19. Combination between the Inclinations of the Enclosure and the Magnetic Field Orientation on the Oscillatory Natural Convection

    Directory of Open Access Journals (Sweden)

    A. Atia

    2016-01-01

    Full Text Available In this paper, we study the combination between the inclinations of the enclosure and the magnetic field orientation on the oscillatory natural convection. For this, a cylindrical enclosure filled with electrically conducting fluid, has an aspect ratio equal to 2, and subjected to a vertical temperature gradient and different uniform magnetic field orientations were considered. The finite volume method is used to discretize the equations of continuity, momentum and energy. Our computer program based on the SIMPLER Algorithm has a good agreement with available experimental and numerical results. The time-dependent flow and temperature field are presented in oscillatory state, for different cases: inclination of the cylinder, under the effect of magnetic field in different orientations (δ = 0°, 30°, 45° and 90° and the combination between them. The results are presented at various inclinations of the cylinder (φ = 0°, 30° and 45°, and the Hartmann numbers Ha ≤ 50. The stability diagrams of the dependence between the complicated situations with the value of the critical Grashof number Grcr and corresponding frequency Frcr, are established according to the numerical results of this investigation. The combination between the studied state has a significant effect on the stabilization of the convective flow, and shows that the best stabilization of oscillatory natural convection is obtained at the inclination of the cylinder φ = 30°, and the applied of radial magnetic field (δ = 0°.

  20. Double-diffusive mixed convection in the slot ventilated enclosure with different arrangements of supplying air flow ports

    Directory of Open Access Journals (Sweden)

    Heng-Sheng Cheng

    2015-03-01

    Full Text Available Steady double-diffusive mixed convection in an enclosure with side venting and discrete heat and contaminant sources is numerically studied under supplying upside and returning downside (STRB mode and returning upside and supplying downside mode (RTSB, respectively. The parameters governing the fluid flow include the Grashof number Gr (102–106, Reynolds number Re (100–500, supplying or returning distance H 1/HT (0–2, Prandtl number Pr (0.7, buoyancy ratio N, and Schmidt number Sc. Effects of Gr, Re, and H 1/HT on the flow patterns, thermal, and species transports were numerically investigated concerning STRB and RTSB modes. Fluid flow, heat, and species transports in the enclosure are visualized and analyzed by the contours of stream function, heat function, and mass function, respectively. Air age was also presented to evaluate the freshness of the enclosed fluid. Averaged Nusselt number of the heat source and Sherwood number of the contaminant source are power-law correlated with Gr, Re, and H 1/HT for two ventilation modes, respectively. The correlations demonstrate that the ratio of averaged Nusselt number to Sherwood number was approximately approaching unity, independent of ventilation modes and values of H 1/HT . This investigation could benefit the future design of room ventilation and thermal removals from the electronic chips.

  1. Effects of surface radiation on natural convection in a rayleigh-benard square enclosure: steady and unsteady conditions

    Science.gov (United States)

    Ridouane, El Hassan; Hasnaoui, Mohammed; Campo, Antonio

    2006-01-01

    Coupled laminar natural convection with radiation in air-filled square enclosure heated from below and cooled from above is studied numerically for a wide variety of radiative boundary conditions at the sidewalls. A numerical model based on the finite difference method was used for the solution of mass, momentum and energy equations. The surface-to-surface method was used to calculate the radiative heat transfer. Simulations were performed for two values of the emissivities of the active and insulated walls (ɛ1=0.05 or 0.85, ɛ2=0.05 or 0.85) and Rayleigh numbers ranging from 103 to 2.3×106 . The influence of those parameters on the flow and temperature patterns and heat transfer rates are analyzed and discussed for different steady-state solutions. The existing ranges of these solutions are reported for the four different cases considered. It is founded that, for a fixed Ra, the global heat transfer across the enclosure depends only on the magnitude of the emissivity of the active walls. The oscillatory behavior, characterizing the unsteady-state solutions during the transitions from bicellular flows to the unicellular flow are observed and discussed.

  2. Mixed convection heat transfer inside a differentially heated square enclosure in presence of a rotating heat conducting cylinder

    Science.gov (United States)

    Alam, Muntasir; Kamruzzaman, Ahsan, Faraz; Hasan, Mohammad Nasim

    2016-07-01

    A numerical study of mixed convection heat transfer phenomena in a square cavity containing a heat conducting rotating cylinder has been investigated. A discrete isoflux heater is placed at the bottom wall of the enclosure while the top wall is kept adiabatic. Left and right sidewalls of the enclosure are assumed to be maintained at constant low temperature. A two-dimensional solution for steady laminar mixed convection flow is obtained by using the finite element scheme based on the Galerkin method of weighted residuals for different rotating speeds of the cylinder varying over the range of 0-1000 keeping the Rayleigh number fixed at 5×104 and the Prandtl number at 0.7. The effects of rotating speeds of the cylinder, its radius and conductivity ratio of the rotating cylinder and working fluid on the streamlines, isotherms, local Nusselt number, average Nusselt number and other heat transfer and fluid flow phenomena are investigated. The results indicate that the flow field, temperature distribution and heat transfer rate are dependent on rotating speeds and cylinder size. However, it has been observed that the effect of conductivity ratio is not so prominent.

  3. Experimental study on Transient Natural Convection in a Cube Enclosure with an Isolated Vertical Cyclically Heated Plate

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The low frequency cyclical transient natural convection in a cube enclosure with an internal isolated vertical heated plate was investigated experimentally.A computer-aided experimental system was designed to generate the cyclical heating power input and also used for data reduction.The effects of the cyclic heating power input amplitude(from 0 to 8 W) and frequency(form 1/5400s-1 to 1/600s-1) as well as the per-cycle time-average power input(from 8 to 24 W)on the transient and time-average Nusselt number were parametrically studied.It was found that for such cyclical transient natural convection with low frequency,the plate heating power input amplitude and frequency have little effects on the time-average Nusselt number as long as the cyclical time-average heating power input remains the same,although the transient Nusselt number may be significantly affected.Therefore,the modified Grashof number based on the plate average heat flux can be used to characterize the time-average heat transfer process.The plate time-average Nusselt number is about 15% less than the infinite-space Nusselt number,The location of the isolated plate in enclosure does not appreciably influence the time-average heat transfer characteristics of the plate.

  4. Evaluation of Ventilation Strategies in New Construction Multifamily Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S.; Berger, D.; Zuluaga, M.

    2014-07-01

    In multifamily buildings, particularly in the Northeast, exhaust ventilation strategies are the norm as a means of meeting both local exhaust and whole-unit mechanical ventilation rates. The issue of where the 'fresh' air is coming from is gaining significance as air-tightness standards for enclosures become more stringent, and the 'normal leakage paths through the building envelope' disappear. CARB researchers have found that the majority of high performance, new construction, multifamily housing in the Northeast use one of four general strategies for ventilation: continuous exhaust only with no designated supply or make-up air source, continuous exhaust with ducted make-up air to apartments, continuous exhaust with supply through a make-up air device integral to the unit HVAC, and continuous exhaust with supply through a passive inlet device, such as a trickle vent. Insufficient information is available to designers on how these various systems are best applied. Product performance data are based on laboratory tests, and the assumption is that products will perform similarly in the field. Proper application involves matching expected performance at expected building pressures, but there is no guarantee that those conditions will exist consistently in the finished building. This research effort, which included several weeks of building pressure monitoring, sought to provide field validation of system performance. The performance of four substantially different strategies for providing make-up air to apartments was evaluated.

  5. Source term and radiation dose estimates for postulated damage to the 102 Building at the General Electric Vallecitos Nuclear Center

    Energy Technology Data Exchange (ETDEWEB)

    Mishima, J.; McPherson, R.B.; Schwendiman, L.C.; Watson, E.C.; Ayer, J.E.

    1979-02-01

    Three scenarios representing significant levels of containment loss due to moderate, substantial, and major damage to the 102 Building at the Vallecitos Nuclear Center are postulated, and the potential radiation doses to the general population as a result of the airborne releases of radionuclides are estimated. The damage scenarios are not correlated to any specific level of seismic activity. The three scenarios are: (1) Moderate damage scenario--perforation of the enclosures in and the structure comprising the Plutonium Analytical Laboratory. (2) Substantial damage scenario--complete loss of containment of the Plutonium Analytical Laboratory and loss of the filters sealing the inlet to the Radioactive Materials Laboratory hot cells. (3) Major damage scenario--the damage outlined in (2) plus the perforation of enclosures holding significant inventories of dispersible plutonium in and the structure comprising the Advanced Fuels Laboratory.

  6. Chryseobacterium chengduensis sp. nov. isolated from the air of captive giant panda enclosures in Chengdu, China*#

    Institute of Scientific and Technical Information of China (English)

    Rong SHE; Zhong-xiang HAO; Lu LUO; Hong LIAO; Zhen-rong CHEN; Guo-quan HAN; San-jie CAO; Rui WU; Qi-gui YAN; Rong HOU; Cai-fang WEN; Li-xin XI; Shan ZHAO

    2016-01-01

    A Gram-negative, aerobic, non-motile, rod-shaped bacterial strain, designated 25-1T,was isolated from the air inside giant panda enclosures at the Chengdu Research Base of Giant Panda Breeding, China. Strain 25-1T grew optimaly at pH 7.0–8.0, at 28–30 °C and in the presence of NaCl concentrations from 0.0% to 0.5 %. 16S rRNA gene sequence analysis indicated that strain 25-1T belongs to the genusChryseobacterium within the familyFlavo-bacteriaceae and is related most closely toC.carnisG81T(96.4% similarity),C. lathyri RBA2-6T (95.8% similarity), and C. zeae JM1085T (95.8% similarity). Its genomic DNA G+C molar composition was 36.2%. The major celular fatty acids wereiso-C15:0 (44.0%),iso-C17:0 3OH (19.8%) and C16:1ω7c/16:1ω6c (12.7%). The only isoprenoid quinone was menaquinone 6 (MK-6). The major polar lipids were phosphatidylethanolamine, two unidentified amino lipids and two unidentified lipids. The DNA–DNA relatedness between strain 25-1TandC. lathyri RBA2-6T was 38%. Phenotypic, genotypic, and phylogenetic characteristics indicated that strain 25-1T is a novel member of the genusChryseobacterium, for which the nameC. chengduensis sp. nov. is proposed. The type strain is 25-1T(CCTCC AB2015133T=DSM 100396T).%题目:分离自成都大熊猫兽舍空气中的一株金黄杆菌属新种的鉴定目的:鉴定菌株25-1T是否是金黄杆菌属的一个新种。创新点:首次从空气中分离到金黄杆菌属的新种。方法:革兰氏染色镜检;磷钨酸染色然后透射电镜观察菌株25-1T形态结构;全自动生理生化鉴定系统(Phoenix™-100)与传统生理生化反应管相结合;H890气象色谱仪进行脂肪酸组分分析;薄板双相层析进行极性脂组分分析;反相高压液相色谱分析法进行呼吸琨组分分析;熔解温度法检测G+C摩尔含量;16S rRNA序列测定及系统发生分析。结论:根据传统特征分类研究结果(形态特征、培养特性和生理生化特征)

  7. Integrating Responsive Building Elements in Buildings

    DEFF Research Database (Denmark)

    Haase, Matthias; Amato, Alex; Heiselberg, Per

    2006-01-01

    There is a global need for a more sustainable building development. About 50% of energy is used in buildings indicating that buildings provide a considerable potential for operational energy savings. Studies were conducted with the following objectives: to perform a state-of-the-art review...... energy strategies to develop guidelines and procedures for estimation of environmental performance of responsive building elements and integrated building concepts This paper introduces the ideas of this collaborative work and discusses its usefulness for Hong Kong and China. Special focus was put...... of responsive building elements, of integrated building concepts and of environmental performance assessment methods to improve and optimize responsive building elements to develop and optimize new building concepts with integration of responsive building elements, HVAC-systems as well as natural and renewable...

  8. The Re-invention of the Tower House for the Construction of Green Buildings NZEB, Integrated With the Vertical Axis Small Wind System

    Science.gov (United States)

    Marino, Francesco Paolo R.

    Nowadays the cultural and economic context aims to create a sustainable "carbon zero" society through energy-efficient green buildings NZEB, but it has so far overlooked a construction type widely spread throughout Europe, especially in the Middle Ages, and that in Italy still characterizes the most beautiful landscapes of Tuscany and other cities: the tower-house. The aim of the research was to verify the possibility of reinventing the type of the familiar tower-house, which is intrinsically directed to conquer the height and therefore higher wind conditions, assuming the installation on the top of a small wind system to use wind energy, to make the building energetically self-sufficient. This building is designed from a wooden structure of a deciduous tree widespread in the Italian region of Basilicata, the Turkish Oak, which, subject to processes of hygrothermal conditioning, can be transformed into the base material to compose laminated timber beams and pillars, able to guarantee a load of exercise, to bending stress, equal to 40.9 N/mm2, as followed by tests in the Laboratory of Engineering of the University of Basilicata, Potenza. With normal wind conditions in the city of Potenza (average of 6.5 m/s), a 5 kW wind turbine mounted at 25 m tall on a 13 m high building is able to provide all the energy the building needs, with its attractive tapered oval top that minimizes turbulence. Entirely made with structures, finishes and natural insulation, the building is a sign in the landscape, history and future together.

  9. Thermal Performance of Hollow Clay Brick with Low Emissivity Treatment in Surface Enclosures

    OpenAIRE

    Roberto Fioretti; Paolo Principi

    2014-01-01

    External walls made with hollow clay brick or block are widely used for their thermal, acoustic and structural properties. However, the performance of the bricks frequently does not conform with the minimum legal requirements or the values required for high efficiency buildings, and for this reason, they need to be integrated with layers of thermal insulation. In this paper, the thermal behavior of hollow clay block with low emissivity treatment on the internal cavity surfaces has been invest...

  10. Sampling and analysis plan for assessment of beryllium in soils surrounding TA-40 building 15

    Energy Technology Data Exchange (ETDEWEB)

    Ruedig, Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-19

    Technical Area (TA) 40 Building 15 (40-15) is an active firing site at Los Alamos National Laboratory. The weapons facility operations (WFO) group plans to build an enclosure over the site in 2017, so that test shots may be conducted year-round. The enclosure project is described in PRID 16P-0209. 40-15 is listed on LANL OSH-ISH’s beryllium inventory, which reflects the potential for beryllium in/on soils and building surfaces at 40-15. Some areas in and around 40-15 have previously been sampled for beryllium, but past sampling efforts did not achieve complete spatial coverage of the area. This Sampling and Analysis Plan (SAP) investigates the area surrounding 40-15 via 9 deep (≥1-ft.) soil samples and 11 shallow (6-in.) soil samples. These samples will fill the spatial data gaps for beryllium at 40-15, and will be used to support OSH-ISH’s final determination of 40-15’s beryllium registry status. This SAP has been prepared by the Environmental Health Physics program in consultation with the Industrial Hygiene program. Industrial Hygiene is the owner of LANL’s beryllium program, and will make a final determination with regard to the regulatory status of beryllium at 40-15.

  11. Building energy analysis tool

    Science.gov (United States)

    Brackney, Larry; Parker, Andrew; Long, Nicholas; Metzger, Ian; Dean, Jesse; Lisell, Lars

    2016-04-12

    A building energy analysis system includes a building component library configured to store a plurality of building components, a modeling tool configured to access the building component library and create a building model of a building under analysis using building spatial data and using selected building components of the plurality of building components stored in the building component library, a building analysis engine configured to operate the building model and generate a baseline energy model of the building under analysis and further configured to apply one or more energy conservation measures to the baseline energy model in order to generate one or more corresponding optimized energy models, and a recommendation tool configured to assess the one or more optimized energy models against the baseline energy model and generate recommendations for substitute building components or modifications.

  12. Evaluation of winter food quality and its variability for red deer in forest environment: overwintering enclosures vs. free-ranging areas

    Directory of Open Access Journals (Sweden)

    Holá Michaela

    2016-09-01

    Full Text Available Populations of European ungulates have grown substantially over recent decades, resulting in considerable environmental and socio-economic impacts. Availability and quality of natural and supplemental food sources are among the main factors driving their population dynamics. Detailed knowledge of food quality of management-targeted species is therefore of primary importance for their successful management. The main aim of this study was to evaluate winter food quality and its variability for an important ungulate species in the Czech Republic - i.e. red deer, using faecal indices (faecal nitrogen, faecal acid detergent fibre, faecal neutral detergent fibre and near infrared reflectance spectroscopy. We compared food quality for red deer and its possible differences between overwintering enclosures (i.e. fenced areas where red deer spend harsh winter conditions and neighbouring unfenced free-ranging areas within two study areas. The results obtained showed that winter food quality and its variability for red deer are of different quality and variability in the overwintering enclosure and neighbouring free-ranging area. The observed differences in concentrations and amounts of variation of faecal indices are most probably related to animal densities at individual study areas. Wildlife managers should therefore keep animals in overwintering enclosures at moderate densities and to provide high quality forage to all individuals in order to balance nutrition of both the individuals inside and outside the enclosures. Nevertheless, further studies are needed in order to provide deeper knowledge on red deer food quality and its variability in space and time.

  13. Study of Shielding Properties of a Rectangular Enclosure with Apertures Having Different Shapes but Same Area Using Modal Method of Moments

    Directory of Open Access Journals (Sweden)

    Chao Zhou

    2013-01-01

    Full Text Available In this study, electric field Shielding Effectiveness (SE of rectangular enclosure with apertures illuminated by vertical polarization plane wave has been studied by using modal method of moment technique. Electric field SE of enclosure with different shape apertures but same area has been c alculated at three different points inside enclosure. To achieve this, assuming appropriate electric field distribution on the aperture, fields inside the cavity are determined using rectangular cavity Green’s function. Electromagnetic fields outside the cavity and scattered due to the aperture are obtained using the free space Green’s function. Matching the tangential magnetic field across the apertures, the integral equation with aperture fields as unknown variables is obtained. A very good agreement among the results of the proposed technique, results available in the literature and experimental results is observed. The simulation results show that the electric field SE is seriously affected by calculation points, aperture shape and the number of aperture. It has been shown that usual assumption made in EMC literature that lower electric field SE near the aperture than at location inside the enclosure farther away from the aperture is not always true to square aperture at some frequency and square aperture has higher electric field SE than rectangular aperture even though they have same area.

  14. [Effects of enclosure on the caloric values of main plant species, litters, and communities in Leymus chinensis steppe in Xilin River Basin, Inner Mongolia].

    Science.gov (United States)

    Gao, Kai; Zhu, Tie-Xia; Wang, Qi-Bing; Han, Guo-Dong

    2012-04-01

    In August 2010, a sampling work was conducted in the plots of the Leymus chinensis steppe, which were fenced in 1979, 1999, and 2004, respectively, in Inner Mongolia Grassland Ecosystem Research Station (IMGERS), aimed to approach the effects of different time periods of enclosure on the caloric values of main plant species, litters, and commnities, and on the total energy storage per unit area. Enclosure had significant effects on the caloric values of the main plant species, litters, and communities, and on the total energy storage per unit area. The total energy storage per unit area in the plots fenced in 1979 and 1999 was significantly higher than that in the plot fenced in 2004, while the caloric values of the litters and communities were in adverse. No significant differences were observed between the plots fenced in 1979 and 1999, respectively. The caloric value of the same plant species varied significantly with the time period of enclosure, and that of different plant species presently definite differences. The caloric value of communities depended on the plant species in the communities, while the total energy storage per unit area depended on the biomass production of the steppe. Both the caloric value of communities and the total energy storage per unit area presented the same variation trend of fluctuation in a short term, but maintained at a stable level over a long period of enclosure, and ecologically reached enrgy balance finally.

  15. 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.

  16. STUDY ON WINDOW-WALL RATIO ON HEAT TRANSFER OF ENCLOSURE STRUCTURE%窗墙比对围护结构传热的影响分析

    Institute of Scientific and Technical Information of China (English)

    卢丽冰; 王玉石; 高梦; 吴国忠; 李栋

    2011-01-01

    以住宅的围护结构、朝向和当地气候的特点为研究对象,选取南、北朝向不同窗墙比的围护结构进行传热分析,建立了不同窗墙比的围护结构传热模型,计算出南北朝向的逐时热流密度值,并作为计算窗户传热的边界条件,利用FLUENT软件对进行数值模拟.模拟结果表明随着窗墙比的增加,围护结构传热量迅速上升.%By taking the enclosure structure and orientation of housing and characteristics of local climate as the research object,the heat transfer analysis on the different window-wall ratios of enclosure structure in southern and northern orientation are studied. With different window-wall ratios, the heat transfer model of enclosure structure is established, which can calculate hourly heat flux value as boundary conditions of calculating window heat transfer. The heat transfer model is simulated using FLUENT software. The results show that heat transfer quantity of enclosure structure increased rapidly with increasing window-wall ratio.

  17. 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.

  18. 环境风作用下室内火灾自然排烟研究%Study on natural smoke exhaust of enclosure fire under surrounding wind

    Institute of Scientific and Technical Information of China (English)

    周云斐; 易亮; 杨洋

    2012-01-01

    以双区模型思想为基础,对环境风作用下建筑室内火灾自然排烟过程进行理论分析和数值模拟研究.引入风压系数计算环境风对建筑各外表面形成的附加风压,在此基础上对排烟口和补气口处内外压差进行分析,同时对烟气流动分别进行质量和能量守恒分析,建立了有风条件下水平自然排烟口烟气质量流率的数学表达式,并给出了烟气层高度和温度的理论计算方法.实际采用水平自然排烟系统时,应对补气口位置进行合理选择,尽量选择处于迎风面的补气口进行自然补气,使总风压系数为正,以提高排烟效率.%Based on the two-layer zone model, theoretical consideration on mass flow rate of smoke vent in natural smoke exhaust of enclosure fire under surrounding wind was performed with a horizontal natural vent. Numerical simulations with a CFD software package (Fire Dynamics Simulator, FDS) were also carried out to get the regularities of dependence for parameters of smoke layer (interface height and temperature) on surrounding wind and the position of air inlet. Wind pressure coefficient was introduced to describe the extra wind pressure on the surfaces of building. Pressure difference across the smoke vent and air inlet under surrounding wind were corrected with the extra wind pressure. Conservation of mass and energy of smoke layer was analyzed and expressions were obtained on mass flow rate of horizontal natural smoke vent under surrounding wind. Overall wind pressure coefficient ( difference of wind pressure coefficient at air inlet and vent) affects smoke exhaust rate to some extent. Calculation of temperature and interface height of smoke layer was consequently provided. In practice while designing natural smoke exhaust system, smoke vent should be located rationally, for example, open the air inlets in windward wall for natural air makeup to enhance the efficiency of extraction with positive overall wind pressure

  19. Contributing to Net Zero Building: High Energy Efficient EIFS Wall Systems

    Energy Technology Data Exchange (ETDEWEB)

    Carbary, Lawrence D. [Dow Corning Corporation; Perkins, Laura L. [Dow Corning Corporation; Serino, Roland [Dryvit Systems, Inc; Preston, Bill [Dryvit Systems, Inc; Kosny, Jan [Fraunhofer USA, Inc. CSE

    2014-01-29

    The team led by Dow Corning collaborated to increase the thermal performance of exterior insulation and finishing systems (EIFS) to reach R-40 performance meeting the needs for high efficiency insulated walls. Additionally, the project helped remove barriers to using EIFS on retrofit commercial buildings desiring high insulated walls. The three wall systems developed within the scope of this project provide the thermal performance of R-24 to R-40 by incorporating vacuum insulation panels (VIPs) into an expanded polystyrene (EPS) encapsulated vacuum insulated sandwich element (VISE). The VISE was incorporated into an EIFS as pre-engineered insulation boards. The VISE is installed using typical EIFS details and network of trained installers. These three wall systems were tested and engineered to be fully code compliant as an EIFS and meet all of the International Building Code structural, durability and fire test requirements for a code compliant exterior wall cladding system. This system is being commercialized under the trade name Dryvit® Outsulation® HE system. Full details, specifications, and application guidelines have been developed for the system. The system has been modeled both thermally and hygrothermally to predict condensation potential. Based on weather models for Baltimore, MD; Boston, MA; Miami, FL; Minneapolis, MN; Phoenix, AZ; and Seattle, WA; condensation and water build up in the wall system is not a concern. Finally, the team conducted a field trial of the system on a building at the former Brunswick Naval Air Station which is being redeveloped by the Midcoast Regional Redevelopment Authority (Brunswick, Maine). The field trial provided a retrofit R-30 wall onto a wood frame construction, slab on grade, 1800 ft2 building, that was monitored over the course of a year. Simultaneous with the façade retrofit, the building’s windows were upgraded at no charge to this program. The retrofit building used 49% less natural gas during the winter of

  20. Building America

    Energy Technology Data Exchange (ETDEWEB)

    Brad Oberg

    2010-12-31

    Builders generally use a 'spec and purchase' business management system (BMS) when implementing energy efficiency. A BMS is the overall operational and organizational systems and strategies that a builder uses to set up and run its company. This type of BMS treats building performance as a simple technology swap (e.g. a tank water heater to a tankless water heater) and typically compartmentalizes energy efficiency within one or two groups in the organization (e.g. purchasing and construction). While certain tools, such as details, checklists, and scopes of work, can assist builders in managing the quality of the construction of higher performance homes, they do nothing to address the underlying operational strategies and issues related to change management that builders face when they make high performance homes a core part of their mission. To achieve the systems integration necessary for attaining 40% + levels of energy efficiency, while capturing the cost tradeoffs, builders must use a 'systems approach' BMS, rather than a 'spec and purchase' BMS. The following attributes are inherent in a systems approach BMS; they are also generally seen in quality management systems (QMS), such as the National Housing Quality Certification program: Cultural and corporate alignment, Clear intent for quality and performance, Increased collaboration across internal and external teams, Better communication practices and systems, Disciplined approach to quality control, Measurement and verification of performance, Continuous feedback and improvement, and Whole house integrated design and specification.

  1. Offshore Membrane Enclosures for Growing Algae (OMEGA: A System for Biofuel Production, Wastewater Treatment, and CO2 Sequestration

    Science.gov (United States)

    Trent, Jonathan; Embaye, Tsegereda; Buckwalter, Patrick; Richardson, Tra-My; Kagawa, Hiromi; Reinsch, Sigrid; Martis, Mary

    2010-01-01

    We are developing Offshore Membrane Enclosures for Growing Algae (OMEGA). OMEGAs are closed photo-bioreactors constructed of flexible, inexpensive, and durable plastic with small sections of semi-permeable membranes for gas exchange and forward osmosis (FO). Each OMEGA modules is filled with municipal wastewater and provided with CO2 from coastal CO2 sources. The OMEGA modules float just below the surface, and the surrounding seawater provides structural support, temperature control, and mixing for the freshwater algae cultures inside. The salinit7 gradient from inside to outside drives forward osmosis through the patches of FO membranes. This concentrates nutrients in the wastewater, which enhances algal growth, and slowly dewaters the algae, which facilitates harvesting. Thy concentrated algal biomass is harvested for producing biofuels and fertilizer. OMEGA system cleans the wastewater released into the surrounding coastal waters and functions as a carbon sequestration system.

  2. Offshore Membrane Enclosure for Growing Algai (Omega) System for Biofuel Production, Wastewater Treatment, and CO2 Sequestration

    Science.gov (United States)

    Trent, Jonathan; Embaye, Tsegereda; Buckwalter, Patrick; Richardson, Tra-My; Kagawa, Hiromi; Reinsch, Sigrid

    2010-01-01

    We are developing Offshore Membrane Enclosures for Growing Algae (OMEGA). OMEGAs are closed photo-bioreactors constructed of flexible, inexpensive, and durable plastic with small sections of semi-permeable membranes for gas exchange and forward osmosis (FO). Each OMEGA modules is filled with municipal wastewater and provided with CO2 from coastal CO2 sources. The OMEGA modules float just below the surface, and the surrounding seawater provides structural support, temperature control, and mixing for the freshwater algae cultures inside. The salinity gradient from inside to outside drives forward osmosis through the patches of FO membranes. This concentrates nutrients in the wastewater, which enhances algal growth, and slowly dewaters the algae, which facilitates harvesting. The concentrated algal biomass is harvested for producing biofuels and fertilizer. OMEGA system cleans the wastewater released into the surrounding coastal waters and functions as a carbon sequestration system.

  3. Thermal Lattice Boltzmann Simulation of Entropy Generation within a Square Enclosure for Sensible and Latent Heat Transfers

    Directory of Open Access Journals (Sweden)

    Alissar Yehya

    2015-12-01

    Full Text Available This paper deals with the numerical simulation of heat transfer and entropy generation in a 2D square enclosure for convective melting. A thermal lattice Boltzmann method (TLBM is used to handle the study, which has been conducted for Prandtl numbers from 0.02 to 70 at Rayleigh numbers of 104 and 105. The results are presented in terms of the total entropy generation, average Bejan number and average Nusselt number. Within the range considered for the key parameters, the entropy generation is found to be controlled by the heat transfer loss for low Prandtl numbers. However, for the large Prandtl numbers, its variation is dominated by shearing losses. Moreover, the presence of the latent heat state decreases the overall thermodynamic losses while increasing the quantity of heat transferred.

  4. Experimental study of water absorption of electronic components and internal local temperature and humidity into electronic enclosure

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan

    2014-01-01

    Corrosion reliability of electronic products is a key factor for electronics industry, and today there is a large demand for performance reliability in large spans of temperature and humidity during day and night shifts. Corrosion failures are still seen due to the effects of temperature, humidity...... and corrosion accelerating species in the atmosphere, and moreover the surface region of printed circuit board assemblies is often contaminated by various contaminating species. In order to evaluate the level of humidity at which failures such as electrochemical migration start to appear on printed circuit......–75 % RH was reached, corresponding to the deliquescence relative humidity level of NaCl. The overall effect of climate (humidity and temperature) has been studied on the internal climate of typical electronic enclosures. The varied parameters included material used for casing, s ize of opening...

  5. ASSESSMENT OF THE ECONOMIC AND ENVIRONMENTAL SUITABILITY OF THE JIU-CORABIA ENCLOSURE FOR LAKE USAGE USING GIS TECHNIQUES

    Directory of Open Access Journals (Sweden)

    Denisa Mariana DAN

    2016-08-01

    Full Text Available One of the three strategic objectives of the Europe 2020 Agenda is to ensure the sustainable management of the natural resources and to fight against climate changes. Considering water to be not only a valuable natural resource for any type of landscape, but also the vital environmental component that ensured a minimum of productivity for the people working the unproductive salinization and gleyzation affected soils in the Jiu-Corabia enclosure, using embankment dams to breake the link between the Danube and the flood organism it created over a timespan of millenia has proven in the last 50 years to be an economic and ecological failure. Since the December 1989 events in Romania, after most of the socialist institutions have proven to be too resource consuming, thus unprofitable or maladaptive, the Jiu-Corabia locals have individually experimented with various land cultivation patterns, all of them based on draught-resistant crops, such as peanuts. In spite of it being the original natural landuse, lake usage has only been scarcely mentioned as a project after the 2006 flood, but after being institutionally rejected, its benefits in terms of ecological restoration, financial productivity have not been further looked into. The current article aims to identify different height level scenarios of lake usage in the Jiu-Corabia enclosure, using GIS technique. Lake volumes are calculated for each scenario with the aim of assessing the volume of water this enclose can absorb during flooding periods, as well as of estimating fish production for when the waters are low and it is not needed as a controlled flood chamber. Other benefits, such as providing a source of humidity for precipitations which will aid the crops nearby, have not been monetized, but contribute to the regional development efforts.

  6. Dynamics of algae growth and nutrients in experimental enclosures culturing bighead carp and common carp:Phosphorus dynamics

    Institute of Scientific and Technical Information of China (English)

    Suiliang Huang; Baoyan Liu; Shaoming Wang; Yang Luo; Adam Szymkiewicz; Romuald Szymkiewicz; Min Wu; Changjuan Zang; Shenglan Du; Joseph Domagalski; Magdalena Gajewska; Feng Gao; Chao Lin; Yong Guo

    2016-01-01

    This is the third paper of the series about “Dynamics of algae growth and nutrients in experimental enclosures culturing bighead carp and common carp”. In this paper, phosphorus dynamics were inves-tigated under the condition of culturing bighead carp and common carp with added fish food (nitrogen dynamics is discussed in the second paper because their behaviors are so different from each other). Nearly fifty days’ observation results indicated that the reservoir water was typical of “phosphorus limited” water, and soluble reactive phosphorus (SRP) was the main constituent of measured total phosphorus (TP). The presence of fish food resulted in significantly higher SRP, dissolved total phos-phorus (DTP) and TP concentrations in contrast with the reservoir water. Moreover, continuous supply of fish food led to the decline of total nitrogen to total phosphorus (TN:TP) from more than 100 to less than 5. Variations in the ratio of TN to TP favored the growth of blue-green algae. Fish species affected phosphorus concentrations, and culturing bait-eating common carp contributed more to reducing the SRP, DTP and TP concentrations than culturing planktivorous bighead carp. 0.5%, 4.1%and 3.1%TP can be removed in enclosures with culturing bighead carp, common carp and mixed bighead carp and common carp, respectively. Abundant phosphorus in the fish culturing activities may be present as the uneaten food, algae cells, and within the water column and sediment, which should be taken into serious con-sideration for the target of future water eutrophication prevention and safety of the drinking water supply.

  7. Practical identification of moisture sources in building assemblies using infrared thermography

    Science.gov (United States)

    McIntosh, Gregory B.; Colantonio, Antonio

    2015-05-01

    Water, in its various phases, in any environment other than desert (hot or cold) conditions, is the single most destructive element that causes deterioration of materials and failure of building assemblies. It is the key element present in the formation of mold and fungi that lead to indoor air quality problems. Water is the primary element that needs to be managed in buildings to ensure human comfort, health and safety. Under the right thermodynamic conditions the detection of moisture in its various states is possible through the use of infrared thermography for a large variety of building assemblies and materials. The difficulty is that moisture is transient and mobile from one environment to another via air movement, vapor pressure or phase change. Building materials and enclosures provide both repositories and barriers to this moisture movement. In real life steady state conditions do not exist for moisture within building materials and enclosures. Thus the detection of moisture is in a constant state of transition. Sometimes you will see it and sometimes you will not. Understanding the limitations at the time of inspection will go a long way to mitigating unsatisfied clients or difficult litigation. Moisture detection can be observed by IRT via three physical mechanisms; latent heat absorption or release during phase change; a change in conductive heat transfer; and a change in thermal capacitance. Complicating the three methodologies is the factor of variable temperature differentials and variable mass air flow on, through and around surfaces being inspected. Building enclosures come in variable assembly types and are designed to perform differently in different environmental regions. Sources for moisture accumulation will vary for different environmental conditions. Detection methodologies will change for each assembly type in different ambient environments. This paper will look at the issue of the methodologies for detection of the presence of moisture and

  8. Building performance modelling for sustainable building design

    National Research Council Canada - National Science Library

    Oduyemi, Olufolahan; Okoroh, Michael

    2016-01-01

    ...) called Ecotect for sustainable building design. Finally, it introduces a design tool analysis of a case study using Ecotect to evaluate various what if scenarios on a proposed multi-use building...

  9. Tribal Green Building Toolkit

    Science.gov (United States)

    This Tribal Green Building Toolkit (Toolkit) is designed to help tribal officials, community members, planners, developers, and architects develop and adopt building codes to support green building practices. Anyone can use this toolkit!

  10. BUILDING 341 Seismic Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Halle, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-06-15

    The Seismic Evaluation of Building 341 located at Lawrence Livermore National Laboratory in Livermore, California has been completed. The subject building consists of a main building, Increment 1, and two smaller additions; Increments 2 and 3.

  11. Green building: sustainable building quality; Green Building: nachhaltige Gebaeudequalitaet

    Energy Technology Data Exchange (ETDEWEB)

    Staub, R.

    2010-07-01

    This article takes a look at the 'Portikon' office building near Zurich, Switzerland, that meets the 'Minergie-P' very low energy consumption requirements. The author is of the opinion that the project can be seen as a reference project for sustainable building technology. The structure of the seven-storey building with a central atrium is described and discussed. The 'Minergie-P' energy concept is discussed, as are the 1,100 square meters of photovoltaic panels on the roof of the building. Heating energy is provided by Zurich's waste incineration plant nearby. Electro-biological aspects in the building are taken care of by appropriate earthing and shielding of cables. The building's facility management system and the installations used are briefly discussed.

  12. Danish building typologies

    DEFF Research Database (Denmark)

    Wittchen, Kim Bjarne; Kragh, Jesper

    The objective of TABULA is to develop a harmonised building typology for European countries. Each national building typology will consist of a set of residential model buildings with characteristic energy-related properties (element areas of the thermal building envelope, U-values, supply system...... efficiencies). The model buildings will each represent a specific construction period of the country in question and a specific building size. Furthermore the number of buildings, flats and the overall floor areas will be given, which are represented by the different building types of the national typologies....

  13. Danish building typologies

    DEFF Research Database (Denmark)

    Wittchen, Kim Bjarne; Kragh, Jesper

    The objective of TABULA is to develop a harmonised building typology for European countries. Each national building typology will consist of a set of residential model buildings with characteristic energy-related properties (element areas of the thermal building envelope, U-values, supply system...... efficiencies). The model buildings will each represent a specific construction period of the country in question and a specific building size. Furthermore the number of buildings, flats and the overall floor areas will be given, which are represented by the different building types of the national typologies....

  14. Danish building typologies and building stock analyses

    DEFF Research Database (Denmark)

    Wittchen, Kim Bjarne; Kragh, Jesper

    enough to meet the government’s plan to make Danish buildings free from use of fossil fuels by 2035. This will probably require around 50 % energy savings in the Danish building stock as a whole. However, the project has proven that dedicated engagement of locals can speed up market penetration...... energy savings in residential buildings. The intension with this analysis was to investigate the possible energy reduction in Denmark if the same approach had been taken for the entire Danish building stock. The report concludes that the ZeroHome initiative clearly results in energy savings, but far from...... for energy savings in the existing Building stock....

  15. Danish building typologies and building stock analyses

    DEFF Research Database (Denmark)

    Wittchen, Kim Bjarne; Kragh, Jesper

    energy savings in residential buildings. The intension with this analysis was to investigate the possible energy reduction in Denmark if the same approach had been taken for the entire Danish building stock. The report concludes that the ZeroHome initiative clearly results in energy savings, but far from...... enough to meet the government’s plan to make Danish buildings free from use of fossil fuels by 2035. This will probably require around 50 % energy savings in the Danish building stock as a whole. However, the project has proven that dedicated engagement of locals can speed up market penetration...... for energy savings in the existing Building stock....

  16. Evaluation of a Natural Ventilation Configuration at a Public Building

    Science.gov (United States)

    Papakonstantinou, K.; Belias, C.; Vlachakis, N.; Statharas, I.

    2007-12-01

    Wind is regarded as the popular passive cooling resource against hot climate in summer. It can transfer heat from human bodies, when the air temperature is lower than the skin temperature. This concept works indoors as well as outdoors. The present paper refers to the numerical simulation of air velocity and temperature concerning single—sided naturally ventilated buildings and more specifically the special case in which air from the external environment is brought inside the building through openings that have the same direction. The paper draws attention to the physical procedures governing air movement during the single—sided natural ventilation. The study presents a mathematical model, implemented in a general computer code, that can provide detailed information on velocity and temperature, prevailing in three-dimensional single—sided ventilated buildings with openings of any geometrical complexity, for given external meteorological conditions. The mathematical model involves the partial differential equations governing flow and heat transfer, in large enclosures. Turbulent flow is simulated and buoyancy effects are taken into account.

  17. Numerical study of magnetic field on mixed convection and entropy generation of nanofluid in a trapezoidal enclosure

    Energy Technology Data Exchange (ETDEWEB)

    Aghaei, Alireza, E-mail: AlirezaAghaei21@gmail.com; Khorasanizadeh, Hossein, E-mail: khorasan@kashanu.ac.ir; Sheikhzadeh, Ghanbarali, E-mail: Sheikhz@kashanu.ac.ir; Abbaszadeh, Mahmoud, E-mail: abbaszadeh.mahmoud@gmail.com

    2016-04-01

    The flow under influence of magnetic field is experienced in cooling electronic devices and voltage transformers, nuclear reactors, biochemistry and in physical phenomenon like geology. In this study, the effects of magnetic field on the flow field, heat transfer and entropy generation of Cu–water nanofluid mixed convection in a trapezoidal enclosure have been investigated. The top lid is cold and moving toward right or left, the bottom wall is hot and the side walls are insulated and their angle from the horizon are 15°, 30°, 45° and 60°. Simulations have been carried out for constant Grashof number of 10{sup 4}, Reynolds numbers of 30, 100, 300 and 1000, Hartmann numbers of 25, 50, 75 and 100 and nanoparticles volume fractions of zero up to 0.04. The finite volume method and SIMPLER algorithm have been utilized to solve the governing equations numerically. The results showed that with imposing the magnetic field and enhancing it, the nanofluid convection and the strength of flow decrease and the flow tends toward natural convection and finally toward pure conduction. For this reason, for all of the considered Reynolds numbers and volume fractions, by increasing the Hartmann number the average Nusselt number decreases. Furthermore, for any case with constant Reynolds and Hartmann numbers by increasing the volume fraction of nanoparticles the maximum stream function decreases. For all of the studied cases, entropy generation due to friction is negligible and the total entropy generation is mainly due to irreversibility associated with heat transfer and variation of the total entropy generation with Hartmann number is similar to that of the average Nusselt number. With change in lid movement direction at Reynolds number of 30 the average Nusselt number and total entropy generation are changed, but at Reynolds number of 1000 it has a negligible effect. - Highlights: • effects of magnetic field on the flow field, heat transfer and entropy generation. • mixed

  18. Global building physics

    DEFF Research Database (Denmark)

    Rode, Carsten

    2013-01-01

    High ambitions are set for the building physics performance of buildings today. No single technology can achieve fulfilment of these ambitions alone. Integrated, multi-facetted solutions and optimization are necessary. A holistic, or ‘global’, technological perspective is needed, which includes all...... aspects of the building as defined in building engineering. We live in an international society and building solutions are developed across country borders. Building physics is a global theme. The International Association of Building Physics has global appeal. This brief article reports the keynote...

  19. Global Building Physics

    DEFF Research Database (Denmark)

    Rode, Carsten

    2012-01-01

    High ambitions are set for the building physics performance of buildings today. No single technology can achieve fulfilment of these ambitions alone. Integrated, multi-facetted solutions and optimization are necessary. A holistic, or “global”, technological perspective is needed, which includes all...... aspects of the building as defined in building engineering. We live in an international society and building solutions are developed across country borders. Building physics is a global theme. The International Association of Building Physics has global appeal. The keynote lecture and this brief paper...

  20. ICT Enhanced Buildings Potentials

    DEFF Research Database (Denmark)

    Christiansson, Per

    2007-01-01

    with focus on virtual building models support, new services and user environment definitions and development, virtual spaces and augmented reality, intelligent building components, application ontologies, and ICT systems integration to illustrate ICT enhanced buildings potentials and R&D needs.  ...... component systems that are accessed and integrated in the real world of building use in different contexts. The ICT systems may be physically or virtually embedded in the building. Already in 1982 AT&T established the 'intelligent buildings', IB, concept due to marketing reasons and the Informart building...