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Sample records for cylinder wall insulation

  1. Anomalous magnetoresistance in magnetized topological insulator cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Siu, Zhuo Bin, E-mail: a0018876@nus.edu.sg [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456 (Singapore); Data Storage Institute, Agency for Science, Technology and Research, Singapore 117608 (Singapore); Jalil, Mansoor B. A. [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117456 (Singapore)

    2015-05-07

    The close coupling between the spin and momentum degrees of freedom in topological insulators (TIs) presents the opportunity for the control of one to manipulate the other. The momentum can, for example, be confined on a curved surface and the spin influenced by applying a magnetic field. In this work, we study the surface states of a cylindrical TI magnetized in the x direction perpendicular to the cylindrical axis lying along the z direction. We show that a large magnetization leads to an upwards bending of the energy bands at small |k{sub z}|. The bending leads to an anomalous magnetoresistance where the transmission between two cylinders magnetized in opposite directions is higher than when the cylinders are magnetized at intermediate angles with respect to each other.

  2. Recording Rapidly Changing Cylinder-wall Temperatures

    Science.gov (United States)

    Meier, Adolph

    1942-01-01

    The present report deals with the design and testing of a measuring plug suggested by H. Pfriem for recording quasi-stationary cylinder wall temperatures. The new device is a resistance thermometer, the temperature-susceptible part of which consists of a gold coating applied by evaporation under high vacuum and electrolytically strengthened. After overcoming initial difficulties, calibration of plugs up to and beyond 400 degrees C was possible. The measurements were made on high-speed internal combustion engines. The increasing effect of carbon deposit at the wall surface with increasing operating period is indicated by means of charts.

  3. Thermal insulation properties of walls

    Directory of Open Access Journals (Sweden)

    Zhukov Aleksey Dmitrievich

    2014-05-01

    Full Text Available Heat-protective qualities of building structures are determined by the qualities of the used materials, adequate design solutions and construction and installation work of high quality. This rule refers both to the structures made of materials similar in their structure and nature and mixed, combined by a construction system. The necessity to ecaluate thermal conductivity is important for a product and for a construction. Methods for evaluating the thermal protection of walls are based on the methods of calculation, on full-scale tests in a laboratory or on objects. At the same time there is a reason to believe that even deep and detailed calculation may cause deviation of the values from real data. Using finite difference method can improve accuracy of the results, but it doesn’t solve all problems. The article discusses new approaches to evaluating thermal insulation properties of walls. The authors propose technique of accurate measurement of thermal insulation properties in single blocks and fragments of walls and structures.

  4. Experimental Thermal Analysis of Diesel Engine Piston and Cylinder Wall

    Directory of Open Access Journals (Sweden)

    Subodh Kumar Sharma

    2015-01-01

    Full Text Available Knowledge of piston and cylinder wall temperature is necessary to estimate the thermal stresses at different points; this gives an idea to the designer to take care of weaker cross section area. Along with that, this temperature also allows the calculation of heat losses through piston and cylinder wall. The proposed methodology has been successfully applied to a water-cooled four-stroke direct-injection diesel engine and it allows the estimation of the piston and cylinder wall temperature. The methodology described here combines numerical simulations based on FEM models and experimental procedures based on the use of thermocouples. Purposes of this investigation are to measure the distortion in the piston, temperature, and radial thermal stresses after thermal loading. To check the validity of the heat transfer model, measure the temperature through direct measurement using thermocouple wire at several points on the piston and cylinder wall. In order to prevent thermocouple wire entanglement, a suitable pathway was designed. Appropriate averaged thermal boundary conditions such as heat transfer coefficients were set on different surfaces for FE model. The study includes the effects of the thermal conductivity of the material of piston, piston rings, and combustion chamber wall. Results show variation of temperature, stresses, and deformation at various points on the piston.

  5. External Insulation of Masonry Walls and Wood Framed Walls

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P. [Building Science Corporation, Somerville, MA (United States)

    2013-01-01

    The use of exterior insulation on a building is an accepted and effective means to increase the overall thermal resistance of the assembly that also has other advantages of improved water management and often increased air tightness of building assemblies. For thin layers of insulation (1” to 1 ½”), the cladding can typically be attached directly through the insulation back to the structure. For thicker insulation layers, furring strips have been added as a cladding attachment location. This approach has been used in the past on numerous Building America test homes and communities (both new and retrofit applications), and has been proven to be an effective and durable means to provide cladding attachment. However, the lack of engineering data has been a problem for many designers, contractors, and code officials. This research project developed baseline engineering analysis to support the installation of thick layers of exterior insulation on existing masonry and frame walls. Furthermore, water management details necessary to integrate windows, doors, decks, balconies and roofs were created to provide guidance on the integration of exterior insulation strategies with other enclosure elements.

  6. External Insulation of Masonry Walls and Wood Framed Walls

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P.

    2013-01-01

    The use of exterior insulation on a building is an accepted and effective means to increase the overall thermal resistance of the assembly that also has other advantages of improved water management and often increased air tightness of building assemblies. For thin layers of insulation (1" to 1 1/2"), the cladding can typically be attached directly through the insulation back to the structure. For thicker insulation layers, furring strips have been added as a cladding attachment location. This approach has been used in the past on numerous Building America test homes and communities (both new and retrofit applications), and has been proven to be an effective and durable means to provide cladding attachment. However, the lack of engineering data has been a problem for many designers, contractors, and code officials. This research project developed baseline engineering analysis to support the installation of thick layers of exterior insulation on existing masonry and frame walls. Furthermore, water management details necessary to integrate windows, doors, decks, balconies and roofs were created to provide guidance on the integration of exterior insulation strategies with other enclosure elements.

  7. Vacuum Insulator Development for the Dielectric Wall Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Harris, J R; Blackfield, D; Caporaso, G J; Chen, Y; Hawkins, S; Kendig, M; Poole, B; Sanders, D M; Krogh, M; Managan, J E

    2008-03-17

    At Lawrence Livermore National Laboratory, we are developing a new type of accelerator, known as a Dielectric Wall Accelerator, in which compact pulse forming lines directly apply an accelerating field to the beam through an insulating vacuum boundary. The electrical strength of this insulator may define the maximum gradient achievable in these machines. To increase the system gradient, we are using 'High Gradient Insulators' composed of alternating layers of dielectric and metal for the vacuum insulator. In this paper, we present our recent results from experiment and simulation, including the first test of a High Gradient Insulator in a functioning Dielectric Wall Accelerator cell.

  8. Noninvasive Stiffness Sensing of Ventricular Wall Based on a Thick-walled Cylinder Model

    Science.gov (United States)

    Higashimori, Mitsuru; Ojio, Takeshi; Takeda, Yasuharu; Sakata, Yasushi; Yamamoto, Kazuhiro; Kaneko, Makoto

    This paper discusses a concept of a noninvasive sensing method that can estimate a left ventricular wall stiffness towards a medical diagnosis. Focusing on not only the strain of ventricular wall but also the displacements of epicardium during diastole of heart beat, we propose an index of ventricular wall stiffness based on a thick-walled cylinder model. Applying the proposed method to the echocardiography, we show statistical results where normal and HFpEF (Heart Failure with preserved Ejection Fraction) can be separated towards a medical diagnosis.

  9. Decoloration of Azo Dye Sunset Yellow by a Coaxial Insulated-Rod-to-Cylinder Underwater Streamer Discharge System

    Institute of Scientific and Technical Information of China (English)

    温小琼; 王明; 丁振峰; 刘贵师

    2012-01-01

    A coaxial insulated-rod-to-cylinder underwater streamer discharge system capable of injecting plasma into a large volume of water was developed and employed to decolorize azo dye sunset yellow. The rod type anode was covered by an insulator tube with a wall thickness of 0.4 mm. A series of slits with a width of 20 μm to 80 μm and a length of about 4 mm were cut onto the wall of the insulator tube. Depending on the solution conductivity, a cylindrical discharge region with a length of 60 mm and a wall thickness of 5 mm to 11 mm forms in the reactor. The influence of the solution conductivity, pH and pulse frequency on the decoloration of sunset yellow was investigated. The results show that the solution conductivity has little effect, while the solution pH and the pulse frequency have significant influence on the decoloration rate of sunset yellow. The decoloration rate of sunset yellow is increased with the increase in pulse frequency. A lower pH in solution promotes the decoloration of sunset yellow while a higher pH inhibits it.

  10. Thermal insulation of outside wall. Aussenwand-Waermedaemmung

    Energy Technology Data Exchange (ETDEWEB)

    Thelen, G.

    1980-09-11

    The invention concerns the thermal insulation of the outside wall with a layer of thermal insulation material glued to the outside wall, a pressure layer applied to this and an outer layer of mortar. The purpose of the invention is to improve thermal insulation of this kind, so that it complies with the conditions of fire class A. The problem is solved by having the thermal insulation layer consisting of mineral or ceramic fibres, which are processed or solidified into plates, mats etc., and having the mats or plates fixed to the wall with pins. The thermal insulation layer built up of ceramic or mineral fibres fulfils the requirements of fire class A and can be used without infringing the present building regulations on facades above the 8th floor.

  11. Parametric Investigation of Optimum Thermal Insulation Thickness for External Walls

    Directory of Open Access Journals (Sweden)

    Omer Kaynakli

    2011-06-01

    Full Text Available Numerous studies have estimated the optimum thickness of thermal insulation materials used in building walls for different climate conditions. The economic parameters (inflation rate, discount rate, lifetime and energy costs, the heating/cooling loads of the building, the wall structure and the properties of the insulation material all affect the optimum insulation thickness. This study focused on the investigation of these parameters that affect the optimum thermal insulation thickness for building walls. To determine the optimum thickness and payback period, an economic model based on life-cycle cost analysis was used. As a result, the optimum thermal insulation thickness increased with increasing the heating and cooling energy requirements, the lifetime of the building, the inflation rate, energy costs and thermal conductivity of insulation. However, the thickness decreased with increasing the discount rate, the insulation material cost, the total wall resistance, the coefficient of performance (COP of the cooling system and the solar radiation incident on a wall. In addition, the effects of these parameters on the total life-cycle cost, payback periods and energy savings were also investigated.

  12. Measure Guideline. Internal Insulation of Masonry Walls

    Energy Technology Data Exchange (ETDEWEB)

    Straube, J. F. [Building Science Corporation (BSC), Somerville, MA (United States); Ueno, K. [Building Science Corporation (BSC), Somerville, MA (United States); Schumacher, C. J. [Building Science Corporation (BSC), Somerville, MA (United States)

    2012-07-01

    This measure guideline provides recommendations for interior insulation assemblies that control interstitial condensation and durability risks; recommendations for acceptable thermal performance are also provided. An illustrated guide of high-risk exterior details (which concentrate bulk water), and recommended remediation details is provided. This is followed by a recommended methodology for risk assessment of a masonry interior insulation project: a series of steps are suggested to assess the risks associated with this retrofit, with greater certainty with added steps.

  13. Measure Guideline: Internal Insulation of Masonry Walls

    Energy Technology Data Exchange (ETDEWEB)

    Straube, J. F.; Ueno, K.; Schumacher, C. J.

    2012-07-01

    This measure guideline provides recommendations for interior insulation assemblies that control interstitial condensation and durability risks; recommendations for acceptable thermal performance are also provided. An illustrated guide of high-risk exterior details (which concentrate bulk water), and recommended remediation details is provided. This is followed by a recommended methodology for risk assessment of a masonry interior insulation project: a series of steps are suggested to assess the risks associated with this retrofit, with greater certainty with added steps.

  14. Analytical Study on Wave Diffraction from a Vertical Circular Cylinder in Front of Orthogonal Vertical Walls

    Institute of Scientific and Technical Information of China (English)

    NING Dezhi; TENG Bin; SONG Xiangqun

    2005-01-01

    In this paper, the principle of mirror image is used to transform the problem of wave diffraction from a circular cylinder in front of orthogonal vertical walls into the problem of diffraction of four symmetric incident waves from four symmetrically arranged circular cylinders, and then the eigenfunction expansion of velocity potential and Grafs addition theorem are used to give the analytical solution to the wave diffraction problem. The relation of the total wave force on cylinder to the distance between the cylinder and orthogonal vertical walls and the incidence angle of wave is also studied by numerical computation.

  15. Wave Diffraction from A Vertical Cylinder with Two Uniform Columns and Porous Outer Wall

    Institute of Scientific and Technical Information of China (English)

    TFNG Rin; HAN Ling; LI Yucheng

    2000-01-01

    Based on a linear model of the pressure difference between two sides of a porous wall and the fluid velocity inside it, an analytic solution is established for wave diffraction from a cylinder with an outer porous column and an inner solid column. Numerical experiments are carried out to examine the effects of the wave force on a porous tow-column cylinder and the wave elevations outside and inside the cylinder due to the porous character of the outer column and the ratio between the radii of the inner and outer columns. The numerical results show that the increase in the coefficient of porosity of the outer column of a double column cylinder will reduce the wave elevation around the cylinder and the wave load on it. The radius of the inner column does not affect too much the wave elevation around the cylinder and the total force on the cylinder.

  16. A new fire performance test for cavity wall insulation

    Directory of Open Access Journals (Sweden)

    Jamison Kristin L.T.

    2016-01-01

    Full Text Available Cavity walls containing combustible insulation present an increased risk for fire propagation in a confined, concealed space. Damage to the building resulting from ignition of combustible insulation can be extensive; especially so, in the absence of horizontal and vertical fire-stops. Current codes and standards assess fire performance of exterior wall assemblies subjected to external ignition sources. However, test methods do not address the potential fire hazard resulting from ignition of combustible insulation within the wall cavity. A fire performance test has been developed that evaluates the fire propagation behavior of combustible insulation in a configuration that is representative of the actual installation. The test utilizes a full scale cavity wall assembly and offers fire performance evaluation of insulation of any thickness for either a 51 mm or 102 mm wide air space. A propane sand burner was selected as the ignition source; in addition to being reliable and repeatable, its heat output was carefully calibrated to be representative of potential ignition scenarios that may occur within a cavity wall. During the 15 minute fire performance test, the sample is continuously subjected to the propane sand burner exposure fire. An acceptable sample will produce a peak chemical heat release rate less than 100 kW and a maximum visible flame height less than 1.8 m. This fire performance test method is being incorporated into FM Approvals Standard for Cavity Walls and Rainscreens, Class Number 4411 [1] and is suitable for incorporation into other codes and standards.

  17. WEIGHT FUNCTION FOR STRESS INTENSITY FACTORS IN ROTATING THICK-WALLED CYLINDER

    Institute of Scientific and Technical Information of China (English)

    CHEN Ai-jun; ZENG Wen-ji

    2006-01-01

    The equation of stress intensity factors(SIF) of internally pressurized thickwalled cylinder was used as the reference case. SIF equation of rotating thick-walled cylinder containing a radial crack along the internal bore was presented in weight function method. The weight function formulas were worked out and can be used for all kinds of depth of cracks, rotating speed, material, size of thick-walled cylinder to calculate the stress intensity factors. The results indicated the validity and effectiveness of these formulas. Meanwhile, the rules of the stress intensity factors in rotating thick-walled cylinder with the change of crack depths and the ratio of outer radius to inner radius were studied. The studies are valuable to engineering application.

  18. Reorganization of Coherent Structures Downstream a Circular Cylinder Located between Two Parallel Walls

    Directory of Open Access Journals (Sweden)

    F. Rehimi

    2011-01-01

    Full Text Available Experiments were performed at low Reynolds numbers in the range 75 Re 275 in the wake of a circular cylinder of dc diameter placed symmetrically between two parallel walls of H height. 2D2C particle image velocimetry (PIV was used to investigate the flow downstream the cylinder. In the unsteady flow regime downstream the cylinder, the detached primary vortices (Pi interact with walls generating secondary ones (Pi’ and modify the cylinder wake dynamic. The kinematical properties (advection velocity, circulation, rotation kinetic energy, etc. of the generated secondary vortices are studied and compared with the primary ones in order to show how the walls influence the von Kármán vortex street. The authors propose here a relation between the circulations and kinetic energies of primary and secondary vortices.

  19. Elastic-plastic Transition of Transversely Isotropic Thick-walled Rotating Cylinder under Internal Pressure

    Directory of Open Access Journals (Sweden)

    Sanjeev Sharma

    2009-05-01

    Full Text Available Elastic-plastic stresses for a transversely isotropic thick-walled rotating cylinder under internal pressure have been obtained by using Seth’s transition theory. It has been observed that a thick-walled circular cylinder made of isotropic material yields at the internal surface at a high pressure as compared to cylinder made of transversely isotropic material. With the increase in angular speed, much less pressure is required for initial yielding at the internal surface for transversely isotropic material as compared to isotropic material. For fullyplastic state, circumferential stress is maximum at the external surface. Thick-walled circular cylinder made of transversely isotropic material requires high percentage increase in pressure to become fully plastic as compared to isotropic cylinder. Therefore, circular cylinder made of transversely isotropic material is on the safer side of the design as compared to cylinder made of  isotropic material.Defence Science Journal, 2009, 59(3, pp.260-264, DOI:http://dx.doi.org/10.14429/dsj.59.1519

  20. Effects of confining walls on heat transfer from a vertical array of isothermal horizontal elliptic cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Yousefi, T.; Paknezhad, M. [Mechanical Engineering Department, Razi University, Kermanshah, Tehran 11365-4563 (Iran); Ashjaee, M.; Yazdani, S. [School of Mechanical Engineering, University of Tehran, Tehran 11365-4563 (Iran)

    2009-09-15

    Steady state two-dimensional natural convection heat transfer from the vertical array of five horizontal isothermal elliptic cylinders with vertical major axis which confined between two adiabatic walls has been studied experimentally. Experiments were carried out using a Mach-Zehnder interferometer. The Rayleigh number based on cylinder major axis was in the range 10{sup 3}{<=}Ra{<=}2.5 x 10{sup 3}, and dimensionless wall spacing 1.5{<=} t/b{<=}9 and infinity. The effect of wall spacing and Rayleigh number on the heat transfer from the individual cylinder and the array were investigated. Experiments are performed for ratio wall spacing to major diameter t/b = 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 9 and infinity. A correlation based on the experimental data for the average Nusselt number of the array as a function of Ra and t/b is presented in the aforementioned ranges. A relation has been derived for optimum wall spacing at which the Nusselt number of the array attains its maximum value. At optimum wall spacing, approximately 10% increase in the heat transfer from the confined array of elliptic cylinders has been observed as compared to the unconfined case. Also, a heat transfer correlation has been proposed for a single elliptic cylinder with vertical major axis and has been compared with earlier works. (author)

  1. Thermal Performance Evaluation of Walls with Gas Filled Panel Insulation

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Desjarlais, Andre Omer [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Atchley, Jerald Allen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-11-01

    Gas filled insulation panels (GFP) are very light weight and compact (when uninflated) advanced insulation products. GFPs consist of multiple layers of thin, low emittance (low-e) metalized aluminum. When expanded, the internal, low-e aluminum layers form a honeycomb structure. These baffled polymer chambers are enveloped by a sealed barrier and filled with either air or a low-conductivity gas. The sealed exterior aluminum foil barrier films provide thermal resistance, flammability protection, and properties to contain air or a low conductivity inert gas. This product was initially developed with a grant from the U.S. Department of Energy. The unexpanded product is nearly flat for easy storage and transport. Therefore, transportation volume and weight of the GFP to fill unit volume of wall cavity is much smaller compared to that of other conventional insulation products. This feature makes this product appealing to use at Army Contingency Basing, when transportation cost is significant compared to the cost of materials. The objective of this study is to evaluate thermal performance of walls, similar to those used at typical Barracks Hut (B-Hut) hard shelters, when GFPs are used in the wall cavities. Oak Ridge National Laboratory (ORNL) tested performance of the wall in the rotatable guarded hotbox (RGHB) according to the ASTM C 1363 standard test method.

  2. Simplified method for the design of cylinder water walls for passive solar heating

    Energy Technology Data Exchange (ETDEWEB)

    van der Mersch, P.L.; Burns, P.J.; Winn, C.B.

    1981-01-01

    A cylinder water wall (CWW) system is considered. The design method allows for direct-gain space above and between the cylinders, which none of the current known design methods include. The design method consists of using design curves, and is oriented to the architectural community. At most, a four-function calculator is necessary. It requires knowing the room dimensions and the room UA and thermal capacitance. Two cylinder sizes and four cylinder spacings may be considered. The method permits determining the size of the glazing, how many cylinders of a given size are required and what spacing is necessary to maintain a desired average minimum, overall average and average maximum temperature in the room. An overview is given of how the design method was developed, as well as a description of how it is applied.

  3. SIMULATED MATHEMATICAL MODEL FOR HIGH PRESSURE CYLINDER WALL TEMPERATURE OF HOMEMADE TURBINE

    Institute of Scientific and Technical Information of China (English)

    Shi Xiaoping; Zhu Yin

    2005-01-01

    In order to balance the contradiction between the demand of high precision and that of short time interval of model computing for the power plant simulator, a set of simulated mathematical models are constructed. The model describes the cylinder wall temperature located at four key positions of the high pressure cylinder. The simulated model is confirmed to be not only simple but also precise via comparison between the simulated results and the autoptic data of a power plant.

  4. Hempcrete Noise Barrier Wall for Highway Noise Insulation : Research & Construction

    OpenAIRE

    KC, Prabesh

    2016-01-01

    The purpose of this thesis was to study the possibility of Hempcrete or hemp-lime composite noise barrier walls in the highways and to construct the walls for the acoustic test according to the European Union Standards EN ISO 717-1 and ISO 10140-2 for air-borne sound insulation. The thesis was commissioned by the company Hemprefine Oy, and all the standard tests were performed in the HAMK-Ruukki Sheet Metal Centre in Hämeenlinna and the VTT Technical Research Centre of Finland Ltd in Espoo. ...

  5. Thermal insulating concrete wall panel design for sustainable built environment.

    Science.gov (United States)

    Zhou, Ao; Wong, Kwun-Wah; Lau, Denvid

    2014-01-01

    Air-conditioning system plays a significant role in providing users a thermally comfortable indoor environment, which is a necessity in modern buildings. In order to save the vast energy consumed by air-conditioning system, the building envelopes in envelope-load dominated buildings should be well designed such that the unwanted heat gain and loss with environment can be minimized. In this paper, a new design of concrete wall panel that enhances thermal insulation of buildings by adding a gypsum layer inside concrete is presented. Experiments have been conducted for monitoring the temperature variation in both proposed sandwich wall panel and conventional concrete wall panel under a heat radiation source. For further understanding the thermal effect of such sandwich wall panel design from building scale, two three-story building models adopting different wall panel designs are constructed for evaluating the temperature distribution of entire buildings using finite element method. Both the experimental and simulation results have shown that the gypsum layer improves the thermal insulation performance by retarding the heat transfer across the building envelopes.

  6. Thermal Insulating Concrete Wall Panel Design for Sustainable Built Environment

    Directory of Open Access Journals (Sweden)

    Ao Zhou

    2014-01-01

    Full Text Available Air-conditioning system plays a significant role in providing users a thermally comfortable indoor environment, which is a necessity in modern buildings. In order to save the vast energy consumed by air-conditioning system, the building envelopes in envelope-load dominated buildings should be well designed such that the unwanted heat gain and loss with environment can be minimized. In this paper, a new design of concrete wall panel that enhances thermal insulation of buildings by adding a gypsum layer inside concrete is presented. Experiments have been conducted for monitoring the temperature variation in both proposed sandwich wall panel and conventional concrete wall panel under a heat radiation source. For further understanding the thermal effect of such sandwich wall panel design from building scale, two three-story building models adopting different wall panel designs are constructed for evaluating the temperature distribution of entire buildings using finite element method. Both the experimental and simulation results have shown that the gypsum layer improves the thermal insulation performance by retarding the heat transfer across the building envelopes.

  7. Forced Convection from Square Cylinder Placed Near a Wall Using Variable Resolution Turbulence Modelling

    Science.gov (United States)

    Ranjan, Pritanshu; Dewan, Anupam

    2015-11-01

    The effect of wall proximity on flow and heat transfer around a square cylinder placed inside a channel is numerically investigated. This flow configuration is a fundamental problem and is widely encountered in several engineering applications. The presence of wall close to the cylinder can alter the shedding process and this in turn can affect the thermal transport in the wake region. Many researchers have studied this phenomenon experimentally but the heat transfer characteristics around a square cylinder placed inside a channel still remain an open question. We present here an insight into this problem. The simulations were carried out for a Reynolds number of 37,000 (based on cylinder diameter, D) and as a function of gap height, G/D, at different blockage ratios. A variable resolution modelling approach (PANS SST k- ω model) was used to study turbulence structures. The results are presented in terms of pressure coefficient, drag coefficient, thermal fluctuations and local and average Nusselt number (Nu). The results obtained showed that, for G / D < 0 . 5 very weak shedding process at random time intervals occurs suggesting the suppression of vortex shedding due to wall. Thus, the local and average Nu decrease as the cylinder is moved towards wall at all blockage ratios.

  8. Heat insulation of combustion chamber walls - A measure to decrease the fuel consumption of I. C. engines

    Energy Technology Data Exchange (ETDEWEB)

    Woschni, G.; Spindler, W.; Kolesa, K.

    1987-01-01

    Experimental investigations were made with a single-cylinder direct-injection Diesel engine with heat-insulated piston. The most important result is an inferior economy compared with the not insulated aluminum-piston engine. It was found that this phenomenon is not caused by neither a changed combustion process nor increased blowby nor different friction losses, but rather by a drastic increase of the heat transfer coefficient during the first part of combustion with increasing surface temperature. This is taken into account in a modified equation for the heat transfer coefficient. Cycle-simulations using this modified equation show that there is neither a gain in fuel economy of naturally aspirated nor of turbocharged nor of turbocompound Diesel engines with ''heat insulated'' combustion chamber walls.

  9. Thermo-Insulating Moulding Sand for thin Walled Castings

    Directory of Open Access Journals (Sweden)

    Cholewa M.

    2014-10-01

    Full Text Available In paper the selection of the composition and determination of main properties of novel moulding sand was described. The mail goal was to create moulding sand characterized by high thermal insulating properties in relations with low specific weight. This type of moulding sand will find application in thin walled castings with complex geometry, in particular for cores of the skeleton castings. In this work the results of the compressive strength, permeability and friability was presented. It was noted that aluminosilicate microspheres are suitable as moulding sand matrix. Influence of the polyglicol addition on quality and properties of the moulding sand was described. The use of the aluminosilicate microspheres allowed to obtain the moulding sand characterized by high insulation rate, low specific weight and good mechanical properties.

  10. Velocity field in a vicinity of cylinder bouncing off horizontal wall

    Science.gov (United States)

    Chara, Z.; Kysela, B.; Dolansky, J.

    2016-06-01

    The paper describes experimental and numerical investigations of velocity fields around a circular cylinder colliding perpendicularly with a plane wall. The cylinder of the diameter D = 20 mm was moving vertically in a water tank and the motion was recorded by a fast digital camera. Reynolds numbers ranged from 3000 to 8100 and the initial positions L of the cylinder above the wall were L/D = 2.5; 3.5; 4.5 and 5.5. An evolution of fluid agitation in an area close to the impact point was based on the results of the velocity field measurements. The numerical simulations were performed using a 2D-LES model.

  11. Discrimination of Cylinders with Different Wall Thicknesses using Neural Networks and Simulated Dolphin Sonar Signals

    DEFF Research Database (Denmark)

    Andersen, Lars Nonboe; Au, Whitlow; Larsen, Jan;

    1999-01-01

    This paper describes a method integrating neural networks into a system for recognizing underwater objects. The system is based on a combination of simulated dolphin sonar signals, simulated auditory filters and artificial neural networks. The system is tested on a cylinder wall thickness...

  12. Analysis of Thick-Walled Cylinder Temperature Field based on the Thermal-Fluid-Solid Coupling

    Directory of Open Access Journals (Sweden)

    Yonghai Wu

    2013-04-01

    Full Text Available The barrel is a special thick-walled cylinder. It is significance to study the temperature distribution of thick-walled cylinder under liquid-cooled state to weapon launch safety and effectiveness. Taking a naval gun barrel as research objective, a unified thermal-fluid-solid coupling model is put forward including barrel solid wall, the cooling water and the water jacket solid wall. The unsteady coupled temperature field of the barrel is calculated at the time of single and continuous firing and some influencing factors such as cooling water flow velocity, barrel wall thickness and so on, are analyzed to the barrel temperature field. The results show that the water cooling effect of the barrel outer is closely related to the wall thickness and the cooling water flow velocity. When the barrel wall thickness is small, increasing the flow velocity increase heat dissipation and reduce barrel wall temperature obviously. When the barrel wall thickness is large, the water cooling effect depends on the total cooling time and small correlation with the velocity of cooling water flow.

  13. Magnetic moment jumps in flat and nanopatterned Nb thin-walled cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Tsindlekht, M.I., E-mail: mtsindl@vms.huji.ac.il [The Racah Institute of Physics, The Hebrew University of Jerusalem, 91904 Jerusalem (Israel); Genkin, V.M.; Felner, I.; Zeides, F.; Katz, N. [The Racah Institute of Physics, The Hebrew University of Jerusalem, 91904 Jerusalem (Israel); Gazi, Š.; Chromik, Š. [The Institute of Electrical Engineering SAS, Dúbravská cesta 9, 84104 Bratislava (Slovakia); Dobrovolskiy, O.V. [Physikalisches Institut, Goethe University, 60438 Frankfurt am Main (Germany); Physics Department, V. Karazin Kharkiv National University, 61077 Kharkiv (Ukraine); Sachser, R.; Huth, M. [Physikalisches Institut, Goethe University, 60438 Frankfurt am Main (Germany)

    2017-02-15

    Highlights: • Magnetization curves of as-prepared and patterned thin-walled cylinders were measured in magnetic fields applied parallel to cylinders axis. • Magnetic moment jumps were observed in magnetic fields lower and above Hc1. • Critical current density in isthmus between two antidots is higher than in a film itself. - Abstract: Penetration of magnetic flux into hollow superconducting cylinders is investigated by magnetic moment measurements. The magnetization curves of a flat and a nanopatterned thin-walled superconducting Nb cylinders with a rectangular cross section are reported for the axial field geometry. In the nanopatterned sample, a row of micron-sized antidots (holes) was milled in the film along the cylinder axis. Magnetic moment jumps are observed for both samples at low temperatures for magnetic fields not only above H{sub c1}, but also in fields lower than H{sub c1}, i. e., in the vortex-free regime. The positions of the jumps are not reproducible and they change from one experiment to another, resembling vortex lattice instabilities usually observed for magnetic fields larger than H{sub c1}. At temperatures above 0.66T{sub c} and 0.78T{sub c} the magnetization curves become smooth for the patterned and the as-prepared sample, respectively. The magnetization curve of a reference flat Nb film in the parallel field geometry does not exhibit jumps in the entire range of accessible temperatures.

  14. Laboratory investigations of moisture conditions in wood frame walls with wood fiber insulation

    OpenAIRE

    Geving, Stig; Lunde, Erik; Holme, Jonas

    2015-01-01

    The purpose of this study was to investigate the moisture conditions in wood frame walls with wood fiber thermal insulation in a Nordic climate. Laboratory measurements were conducted on 15 different wall configurations. The test results showed that the wall configurations with wood fiber insulation performed rather similar as those with mineral wool, in regard to measured relative humidity at the external side of the insulation layer. The laboratory tests showed that wood fiber insu...

  15. Numerical Comparison of Active Acoustic and Structural Noise Control in a Stiffened Double Wall Cylinder

    Science.gov (United States)

    Grosveld, Ferdinand W.

    1996-01-01

    The active acoustic and structural noise control characteristics of a double wall cylinder with and without ring stiffeners were numerically evaluated. An exterior monopole was assumed to acoustically excite the outside of the double wall cylinder at an acoustic cavity resonance frequency. Structural modal vibration properties of the inner and outer shells were analyzed by post-processing the results from a finite element analysis. A boundary element approach was used to calculate the acoustic cavity response and the coupled structural-acoustic interaction. In the frequency region of interest, below 500 Hz, all structural resonant modes were found to be acoustically slow and the nonresonant modal response to be dominant. Active sound transmission control was achieved by control forces applied to the inner or outer shell, or acoustic control monopoles placed just outside the inner or outer shell. A least mean square technique was used to minimize the interior sound pressures at the nodes of a data recovery mesh. Results showed that single acoustic control monopoles placed just outside the inner or outer shells resulted in better sound transmission control than six distributed point forces applied to either one of the shells. Adding stiffeners to the double wall structure constrained the modal vibrations of the shells, making the double wall stiffer with associated higher modal frequencies. Active noise control obtained for the stiffened double wall configurations was less than for the unstiffened cylinder. In all cases, the acoustic control monopoles controlled the sound transmission into the interior better than the structural control forces.

  16. Exact and numerical elastodynamic solutions for thick-walled functionally graded cylinders subjected to pressure shocks

    Energy Technology Data Exchange (ETDEWEB)

    Shariyat, M., E-mail: m_shariyat@yahoo.co [Faculty of Mechanical Engineering, K.N. Toosi University of Technology, Pardis Street, Molla-Sadra Avenue, Vanak Square, P.O. Box: 19395-1999, Tehran 19991 43344 (Iran, Islamic Republic of); Nikkhah, M.; Kazemi, R. [Faculty of Mechanical Engineering, K.N. Toosi University of Technology, Pardis Street, Molla-Sadra Avenue, Vanak Square, P.O. Box: 19395-1999, Tehran 19991 43344 (Iran, Islamic Republic of)

    2011-02-15

    In the present paper, analytical and numerical elastodynamic solutions are developed for long thick-walled functionally graded cylinders subjected to arbitrary dynamic and shock pressures. Both transient dynamic response and elastic wave propagation characteristics are studied in these non-homogeneous structures. Variations of the material properties across the thickness are described according to both polynomial and power law functions. A numerically consistent transfinite element formulation is presented for both functions whereas the exact solution is presented for the power law function. The FGM cylinder is not divided into isotropic sub-cylinders. An approach associated with dividing the dynamic radial displacement expression into quasi-static and dynamic parts and expansion of the transient wave functions in terms of a series of the eigenfunctions is employed to propose the exact solution. Results are obtained for various exponents of the functions of the material properties distributions, various radius ratios, and various dynamic and shock loads.

  17. Vorticity generation and wake transition for a translating circular cylinder: Wall proximity and rotation effects

    DEFF Research Database (Denmark)

    Hourigan, K.; Rao, A.; Brøns, Morten

    2013-01-01

    The wake transitions of generic bluff bodies, such as a circular cylinder, near a wall are important because they provide understanding of different transition paths towards turbulence, and give some insight into the effect of surface modifications on the flow past larger downstream structures....... In this article, the fundamentals of vorticity generation and transport for the two-dimensional flow of incompressible Newtonian fluids are initially reviewed. Vorticity is generated only at boundaries by tangential pressure gradients or relative acceleration. After generation, it can cross......-annihilate with opposite-signed vorticity, and can be stored at a free surface, thus conserving the total vorticity, or circulation. Vorticity generation, diffusion and storage are demonstrated for a cylinder translating and rotating near a wall. The wake characteristics and the wake transitions are shown to change...

  18. Moisture Durability Assessment of Selected Well-insulated Wall Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Pallin, Simon B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Boudreaux, Philip R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kehrer, Manfred [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hun, Diana E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jackson, Roderick K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Desjarlais, Andre Omer [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    This report presents the results from studying the hygrothermal performance of two well-insulated wall assemblies, both complying with and exceeding international building codes (IECC 2015 2014, IRC 2015). The hygrothermal performance of walls is affected by a large number of influential parameters (e.g., outdoor and indoor climates, workmanship, material properties). This study was based on a probabilistic risk assessment in which a number of these influential parameters were simulated with their natural variability. The purpose of this approach was to generate simulation results based on laboratory chamber measurements that represent a variety of performances and thus better mimic realistic conditions. In total, laboratory measurements and 6,000 simulations were completed for five different US climate zones. A mold growth indicator (MGI) was used to estimate the risk of mold which potentially can cause moisture durability problems in the selected wall assemblies. Analyzing the possible impact on the indoor climate due to mold was not part of this study. The following conclusions can be reached from analyzing the simulation results. In a hot-humid climate, a higher R-value increases the importance of the airtightness because interior wall materials are at lower temperatures. In a cold climate, indoor humidity levels increase with increased airtightness. Air leakage must be considered in a hygrothermal risk assessment, since air efficiently brings moisture into buildings from either the interior or exterior environment. The sensitivity analysis of this study identifies mitigation strategies. Again, it is important to remark that MGI is an indicator of mold, not an indicator of indoor air quality and that mold is the most conservative indicator for moisture durability issues.

  19. Design and analysis of Stress on Thick Walled Cylinder with and with out Holes

    Directory of Open Access Journals (Sweden)

    G.Raju

    2015-01-01

    Full Text Available The conventional elastic analysis of thick walled cylinders to final radial & hoop stresses is applicable for the internal pressures up to yield strength of material. The stress is directly proportional to strain up to yield point Beyond elastic point, particularly in thick walled cylinders. The operating pressures are reduced or the material properties are strengthened. There is no such existing theory for the stress distributions around radial holes under impact of varying internal pressure. Present work puts thrust on this area and relation between pressure and stress distribution is plotted graphically based on observations. Here focus is on pure mechanical analysis & hence thermal, effects are not considered. The thick walled cylinders with a radial cross-hole ANSYS Macro program employed to evaluate the fatigue life of vessel. Stresses that remain in material even after removing applied loads are known as residual stresses. These stresses occur only when material begins to yield plastically. Residual stresses can be present in any mechanical structure because of many causes. Residual stresses may be due to the technological process used to make the component. Manufacturing processes lead to plastic deformation. Elasto plastic analysis with bilinear kinematic hardening material is performed to know the effect of hole sizes. It is observed that there are several factors which influence stress intensity factors. The Finite element analysis is conducted using commercial solvers ANSYS & CATIA. Theoretical formulae based results are obtained from MATLAB programs. The results are presented in form of graphs and tables.

  20. 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.

  1. 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.

  2. On what controls the spacing of spontaneous adiabatic shear bands in collapsing thick-walled cylinders

    Directory of Open Access Journals (Sweden)

    Lovinger Zev

    2015-01-01

    Full Text Available Shear bands formation in collapsing thick walled cylinders occurs in a spontaneous manner. The advantage of examining spontaneous, as opposed to forced shear localization, is that it highlights the inherent susceptibility of the material to adiabatic shear banding without prescribed geometrical constraints. The Thick-Walled Cylinder technique (TWC provides a controllable and repeatable technique to create and study multiple adiabatic shear bands. The technique, reported in the literature uses an explosive cylinder to create the driving force, collapsing the cylindrical sample. Recently, we developed an electro-magnetic set-up using a pulsed current generator to provide the collapsing force, replacing the use of explosives. Using this platform we examined the shear band evolution at different stages of formation in 7 metallic alloys, spanning a wide range of strength and failure properties. We examined the number of shear bands and spacing between them for the different materials to try and figure out what controls these parameters. The examination of the different materials enabled us to better comprehend the mechanisms which control the spatial distribution of multiple shear bands in this geometry. The results of these tests are discussed and compared to explosively driven collapsing TWC results in the literature and to existing analytical models for spontaneous adiabatic shear localization.

  3. Unified solution of limit loads of thick wall cylinder subject to external pressure considering strain softening

    Institute of Scientific and Technical Information of China (English)

    CHEN Changfu; XIAO Shujun; YANG Yu

    2007-01-01

    Based on the unified strength theory [1],a unified strength criterion for strain softening materials,such as concrete or rock,was derived,and the elastic and plastic limit loads of a thick-walled cylinder made of these materials subject to external pressure were also given.In addition,the influence of some factors on the limit loads of such cylinders as the ratio of the external radius to intemal radius,rb/ra,the coefficient b,which reflects the effect of medium principal stress and the normal stress of the relevant surface on the material destroy degree,the ratio of tensile strength to compressed strength of the material,α,and the damage variable β were discussed in detail.Some examples were given and some meaningful results were obtained.

  4. The Heat Transfer Coefficient of Recycled Concrete Bricks Combination with EPS Insulation Board Wall

    Directory of Open Access Journals (Sweden)

    Jianhua Li

    2015-01-01

    Full Text Available Four tectonic forms samples were conducted to test their heat transfer coefficients. By analyzing and comparing the test values and theoretical values of the heat transfer coefficient, a corrected-value calculation method for determining the heat transfer coefficient was proposed; the proposed method was proved to be reasonably correct. The results indicated that the recycled concrete brick wall heat transfer coefficient is higher than that of the clay brick wall, the heat transfer coefficient of recycled concrete brick wall could be effectively reduced when combined with the EPS insulation board, and the sandwich insulation type was better than that of external thermal insulation type.

  5. Numerical simulation of flow past twin near-wall circular cylinders in tandem arrangement at low Reynolds number

    Directory of Open Access Journals (Sweden)

    Guo-qiang Tang

    2015-10-01

    Full Text Available Fluid flow past twin circular cylinders in a tandem arrangement placed near a plane wall was investigated by means of numerical simulations. The two-dimensional Navier-Stokes equations were solved with a three-step finite element method at a relatively low Reynolds number of Re = 200 for various dimensionless ratios of and , where D is the cylinder diameter, L is the center-to-center distance between the two cylinders, and G is the gap between the lowest surface of the twin cylinders and the plane wall. The influences of and on the hydrodynamic force coefficients, Strouhal numbers, and vortex shedding modes were examined. Three different vortex shedding modes of the near wake were identified according to the numerical results. It was found that the hydrodynamic force coefficients and vortex shedding modes are quite different with respect to various combinations of and . For very small values of , the vortex shedding is completely suppressed, resulting in the root mean square (RMS values of drag and lift coefficients of both cylinders and the Strouhal number for the downstream cylinder being almost zero. The mean drag coefficient of the upstream cylinder is larger than that of the downstream cylinder for the same combination of and . It is also observed that change in the vortex shedding modes leads to a significant increase in the RMS values of drag and lift coefficients.

  6. A comparative study on effect of plain- and wavy-wall confinement on wake characteristics of flow past circular cylinder

    Indian Academy of Sciences (India)

    R DEEPAKKUMAR; S JAYAVEL; SHALIGRAM TIWARI

    2017-06-01

    A first attempt is made for identifying the wake characteristics of circular cylinder confined by a wavy wall at laminar flow regime. Numerical study of flow characteristics past circular cylinder with wavy-wall confinement perpendicular to cylinder axis has been carried out in the range of Reynolds number 20–100. Thefinite volume-based CFD solver Ansys Fluent (Version 15.0) is used for computations. The results are presented in the form of streamline plots, mean drag co-efficient, flow separation angle and recirculation length. Wavywall confinement leads to highly significant changes in the cylinder wake such as the evolution of strong x-plane vortices, enhanced fluid mixing, wake suppression near the crest region and vortex stretching near the trough region on the downstream of the cylinder has been observed. Flow separation angle varies significantly along the axis of the cylinder. Increased wall shear stress on rear surface of the cylinder has also been observed. The part of vorticity magnitude as compared to strain rate has been distinguished and identified using vortex identification methods such as Q-criterion and Lambda-2 criterion.

  7. Investigation of torsional vibrations in thick walled hollow poroelastic cylinder using Biot's extension theory

    Indian Academy of Sciences (India)

    Malla Reddy Perati; Rajitha Gurijala

    2015-09-01

    This paper deals with the study of torsional vibrations of thick walled hollow poroelastic cylinder using Biot's extension theory. Considering the boundaries to be stress free, the frequency equation is obtained in the presence of dissipation which is transcendental and complex valued in nature. In the special case of poroelastic thin shell, frequency equation is separated into two real valued equations giving propagation velocity and attenuation coefficient. From the numerical results in the case of sandy sediment, it is clear that the values of propagation velocity are, in general, less than that of attenuation coefficient.

  8. Theoretical Analysis of Noise of Piston Knocking Cylinder Wall in Automotive Engines

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on the loading conditions of engine, applying difference method to solve the hydrodynamic lubrication equation of piston skirt movement, the force acting on piston skirt and the moment on wrist pin were obtained. A computer program for simulating the piston second order motion was conducted to calculate the lateral motion of the upper part and the bottom part of piston skirts of the engine of automotive model CA1091. From the simulated result, the maximal impacting phase and the maximal impacting region of the piston were obtained. The result can be used for designing engine, diagnosing the noise of piston knocking cylinder wall and explaining many practical fault phenomena in theory.

  9. Determination of the Airborne Sound Insulation of a Straw Bale Partition Wall

    Science.gov (United States)

    Teslík, Jiří; Fabian, Radek; Hrubá, Barbora

    2017-06-01

    This paper describes the results of a scientific project focused on determining of the Airborne Sound Insulation of a peripheral non-load bearing wall made of straw bales expressed by Weighted Sound Reduction Index. Weighted Sound Reduction Index was determined by measuring in the certified acoustic laboratory at the Faculty of Mechanical Engineering at Brno University of Technology. The measured structure of the straw wall was modified in combinations with various materials, so the results include a wide range of possible compositions of the wall. The key modification was application of plaster on both sides of the straw bale wall. This construction as is frequently done in actual straw houses. The additional measurements were performed on the straw wall with several variants of additional wall of slab materials. The airborne sound insulation value has been also measured in separate stages of the construction. Thus it is possible to compare and determinate the effect of the single layers on the airborne sound insulation.

  10. Technology Solutions Case Study: Retrofit Measures for Embedded Wood Members in Insulated Mass Masonry Walls

    Energy Technology Data Exchange (ETDEWEB)

    K. Ueno

    2015-10-01

    In this project, the Building Science Corporation team studied a historic brick building in Lawrence, Massachusetts, which is being renovated into 10 condominium units and adding insulation to the interior side of walls of such masonry buildings.

  11. Expert Meeting Report: Interior Insulation Retrofit of Mass Masonry Wall Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K.; Van Straaten, R.

    2012-02-01

    The Building Science Consortium held an Expert Meeting on Interior Insulation Retrofit of Mass Masonry Wall Assemblies on July 30, 2011 at the Westford Regency Hotel in Westford, MA. This report outlines the extensive information that was presented on assessment of risk factors for premature building deterioration due to interior insulation retrofits, and methods to reduce such risks.

  12. Expert Meeting Report. Interior Insulation Retrofit of Mass Masonry Wall Assemblies

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-02-01

    The Building Science Consortium held an Expert Meeting on Interior Insulation Retrofit of Mass Masonry Wall Assemblies on July 30, 2011, at the Westford Regency Hotel in Westford, MA. This report outlines the extensive information that was presented on assessment of risk factors for premature building deterioration due to interior insulation retrofits, and methods to reduce such risks.

  13. Measure Guideline. Installing Rigid Foam Insulation on the Interior of Existing Brick Walls

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, Hariharan [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Klocke, Steve [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Puttagunta, Srikanth [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States)

    2012-06-01

    This measure guideline provides information on an effective method to insulate the interior of existing brick masonry walls with extruded polystyrene (XPS) insulation board. The guide outlines step-by-step design and installation procedures while explaining the benefits and tradeoffs where applicable. The authors intend that this document be useful to a varied audience that includes builders,remodelers, contractors and homeowners.

  14. Measure Guideline: Installing Rigid Foam Insulation on the Interior of Existing Brick Walls

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, H.; Klocke, S.; Puttagunta, S.

    2012-06-01

    This measure guideline provides information on an effective method to insulate the interior of existing brick masonry walls with extruded polystyrene (XPS) insulation board. The guide outlines step-by-step design and installation procedures while explaining the benefits and tradeoffs where applicable. The authors intend that this document be useful to a varied audience that includes builders, remodelers, contractors and homeowners.

  15. The influence of ventilated façade on sound insulation properties of envelope walls

    OpenAIRE

    2017-01-01

    Presented article deals with sound insulation properties of timber structures’ envelope walls. Particularly, the influence of heavy board ventilated façade on laboratory airborne sound insulation R and Rw in dB was studied. The installation method and gaps between façade boards can cause building defects originating in overrating the influence of ventilated cladding on envelope wall acoustic parameters. Real constructions were built for the experimental purposes and measurements, one with gap...

  16. Small-scale deflagration cylinder test with velocimetry wall-motion diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Hooks, Daniel E [Los Alamos National Laboratory; Hill, Larry G [Los Alamos National Laboratory; Pierce, Timothy H [Los Alamos National Laboratory

    2010-01-01

    Predicting the likelihood and effects of outcomes resultant from thermal initiation of explosives remains a significant challenge. For certain explosive formulations, the general outcome can be broadly predicted given knowledge of certain conditions. However, there remain unexplained violent events, and increased statistical understanding of outcomes as a function of many variables, or 'violence categorization,' is needed. Additionally, the development of an equation of state equivalent for deflagration would be very useful in predicting possible detailed event consequences using traditional hydrodynamic detonation moders. For violence categorization, it is desirable that testing be efficient, such that it is possible to statistically define outcomes reliant on the processes of initiation of deflagration, steady state deflagration, and deflagration to detonation transitions. If the test simultaneously acquires information to inform models of violent deflagration events, overall predictive capabilities for event likelihood and consequence might improve remarkably. In this paper we describe an economical scaled deflagration cylinder test. The cyclotetramethylene tetranitramine (HMX) based explosive formu1lation PBX 9501 was tested using different temperature profiles in a thick-walled copper cylindrical confiner. This test is a scaled version of a recently demonstrated deflagration cylinder test, and is similar to several other thermal explosion tests. The primary difference is the passive velocimetry diagnostic, which enables measurement of confinement vessel wall velocities at failure, regardless of the timing and location of ignition.

  17. Measure Guideline: Incorporating Thick Layers of Exterior Rigid Insulation on Walls

    Energy Technology Data Exchange (ETDEWEB)

    Lstiburek, Joseph [Building Science Corporation, Westford, MA (United States); Baker, Peter [Building Science Corporation, Westford, MA (United States)

    2015-04-01

    This measure guideline provides information about the design and construction of wall assemblies that use layers of rigid exterior insulation thicker than 1-½ inches and that require a secondary cladding attachment location exterior to the insulation. The guideline is separated into several distinct sections that cover: fundamental building science principles relating to the use of exterior insulation on wall assemblies; design principles for tailoring this use to the specific project goals and requirements; and construction detailing to increase understanding about implementing the various design elements.

  18. Measure Guideline. Incorporating Thick Layers of Exterior Rigid Insulation on Walls

    Energy Technology Data Exchange (ETDEWEB)

    Lstiburek, Joseph [Building Science Corporation, Westford, MA (United States); Baker, Peter [Building Science Corporation, Westford, MA (United States)

    2015-04-09

    This measure guideline, written by the U.S. Department of Energy’s Building America team Building Science Corporation, provides information about the design and construction of wall assemblies that use layers of rigid exterior insulation thicker than 1-½ in. and that require a secondary cladding attachment location exterior to the insulation. The guideline is separated into several distinct sections that cover: (1) fundamental building science principles relating to the use of exterior insulation on wall assemblies; (2) design principles for tailoring this use to the specific project goals and requirements; and (3) construction detailing to increase understanding about implementing the various design elements.

  19. Thermal transmittance of reed-insulated walls in a purpose-built test house

    Directory of Open Access Journals (Sweden)

    M. Miljan

    2014-03-01

    Full Text Available We studied the construction and thermal properties of walls insulated with reed, to enable comparisons with other wall structures that are widely used in building. In 2010 we built a test house insulated with reed adjacent to the Estonian University of Life Sciences in Tartu. The load-bearing structure of the house was a timber frame, and four different technologies were used to place reed insulation in its external walls. The thickness of the reed layer was 450 mm in all cases, and both sides (inside and outside of the walls were rendered with clay plaster. Records were kept of time spent and materials used in construction of the different types of walls, and these data were used to calculate unit (m-2 requirements of time and materials for each wall type to enable direct comparisons. From October 2010 to March 2012, heat flow plates were used to measure the thermal transmittance of the walls of the completed house and the results were compared with the thermal transmittance requirements set by Estonian legislation. Only one of the test walls met the Estonian standard. This was insulated with compressed loose reed, placed horizontally in the wall.

  20. Retrofit with Interior Insulation on Solid Masonry Walls in Cool Temperate Climates

    DEFF Research Database (Denmark)

    Bjarløv, Søren Peter; Finken, G.R.; Odgaard, Tommy

    2015-01-01

    For historic buildings, where an alteration of the exterior façade is not wanted, interior insulation can be the solution to improve the indoor climate and reduce heat loss, but might also introduce moisture problems like condensation in the wall. Capillary active/hydrophilic insulation materials...... have been introduced to cope with the moisture problem. An extensive amount of calculations indicating where the challenges lie in the complex work with interior insulation in cool temperate climate has been carried out. In areas with high precipitation like Denmark, capillary active insulation may...

  1. Effect of wall proximity of two staggered triangular cylinders on the transport process in a channel

    Directory of Open Access Journals (Sweden)

    Mousa Farhadi

    2016-09-01

    Full Text Available A numerical investigation has been carried out to analyze the heat transfer and the flow field around two isothermal triangular cylinders of equal size placed staggered in a horizontal plane channel with adiabatic walls. Computations have been carried out for Reynolds numbers (based on triangle width 100, 250, and 350, lateral gap ratios (d/B 0, 0.5, and 1, and longitudinal gap ratios (S/B 1, 2, 3 and 4. The effect of longitudinal and lateral gap between obstacles and proximity of channel walls is investigated. Results show that when obstacles are placed in close vicinity of the channel's wall (d/B = 1, vortex shedding disappears at the downstream of triangles at Re = 100 and 250 at all S/B, but for Re = 350 creating and disappearing of the vortex shedding depend on the longitudinal gap ratio (S/B. Proximity of obstacles has more effect on the second triangle than the first triangle especially from longitudinal gap ratio equals 2, so that with approaching the channel wall, the Nusselt number for the first triangle decreases, while for the second triangle a different behavior is seen. Staggered arrangement causes the Nusselt number of the second triangle to become greater than the first triangle.

  2. Composite Behavior of a Novel Insulated Concrete Sandwich Wall Panel Reinforced with GFRP Shear Grids: Effects of Insulation Types

    Directory of Open Access Journals (Sweden)

    JunHee Kim

    2015-03-01

    Full Text Available A full-scale experimental program was used in this study to investigate the structural behavior of novel insulated concrete sandwich wall panels (SWPs reinforced with grid-type glass-fiber-reinforced polymer (GFRP shear connectors. Two kinds of insulation-expanded polystyrene (EPS and extruded polystyrene (XPS with 100 mm thickness were incased between the two concrete wythes to meet the increasing demand for the insulation performance of building envelope. One to four GFRP shear grids were used to examine the degree of composite action of the two concrete wythes. Ten specimens of SWPs were tested under displacement control subjected to four-point concentrated loads. The test results showed that the SWPs reinforced with GFRP grids as shear connectors developed a high degree of composite action resulting in high flexural strength. The specimens with EPS foam exhibited an enhanced load-displacement behavior compared with the specimens with XPS because of the relatively stronger bond between insulation and concrete. In addition, the ultimate strength of the test results was compared to the analytical prediction with the mechanical properties of only GRFP grids. The specimens with EPS insulation presented higher strength-based composite action than the ones with XPS insulation.

  3. Investigation of interior post-insulated masonry walls with wooden beam ends

    DEFF Research Database (Denmark)

    Morelli, Martin; Svendsen, Svend

    2013-01-01

    investigated using both thermal and hygrothermal simulation software. The results show that the risk to incurring moisture problems at the wooden beam ends can be resolved by not insulating that portion of the wall directly above and below the floor division. Additionally, this proposed retrofit measure would......The preponderant number of multistorey buildings constructed in Denmark in the period between 1850 and 1930 were built with masonry walls incorporating wooden floor beams. Given the nature of this construction, it is supposed that significant energy savings could be achieved by simply insulating...... of the wall, and this in turn may lead to increased freeze–thaw damages and moisture problems at the beam ends embedded in the masonry, when the masonry facade is subjected to driving rain. This article presents a method to investigate retrofit measures of interior-insulated masonry walls having wooden floor...

  4. Measure Guideline: Wall Air Sealing and Insulation Methods in Existing Homes; An Overview of Opportunity and Process

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, S.; Stephenson, R.

    2012-09-01

    This guide provides renovators and retrofit contractors an overview of considerations when including wall air sealing and insulation in an energy retrofit project. It also outlines the potential project risks, various materials for insulating, possible field inspections needed, installation procedures, as well as the benefits and drawbacks. The purpose of this document is to provide the outline of the overview and process of insulating and air sealing walls so that home retrofit professionals can identify approaches to air sealing and insulation measures.

  5. Reduction of the residual stresses in cold expanded thick-walled cylinders by plastic compression

    Institute of Scientific and Technical Information of China (English)

    V.F. SKVORTSOV; A.O. BOZNAK; A.B. KIM; A. Yu ARLYAPOV; A.I. DMITRIEV

    2016-01-01

    We suppose that in order to maintain high accuracy of holes and to lower residual stresses after cold expansion of thick-walled cylinders, which undergo cross-section plastic deformation, it is necessary to perform axial plastic compression and subsequent cold expansion with small interferences. To test this hypothesis, we studied hoop, radial and axial residual stresses in cylinders made of carbon steel AISI 1050 with hole diameter of 5 mm, outer diameter of 15 mm and length of 30 mm by Sachs method as well as accuracy of expanded holes. It is found that double cold expansion with total interference equal to 5.1%generates hoop residual stresses with largest absolute value equal to 284 MPa and ensures high holes accuracy (IT7). After plastic compression with strain equal to 0.5 and 1%the mentioned stresses reduced to 120 and 75 MPa respectively, and accuracy of the holes reduced as well. Subsequent cold expansion with small interference equal to 0.9%helps to restore holes accuracy (IT7) gained by double cold expansion and ensure that absolute value of hoop residual stresses (177 MPa) is lower compared to double cold expansion.

  6. Numerical investigation of sound transmission through double wall cylinders with respect to active noise control

    Science.gov (United States)

    Coats, T. J.; Silcox, R. J.; Lester, H. C.

    Market pressure for more fuel efficient air travel has led to increased use of turboprop and higher bypass turbofan engines. The low frequency components of propeller, jet and boundary layer noise are difficult to attenuate with conventional passive techniques. Weight and geometric restrictions for sound absorbing meterials limit the amount and type of treatment that may be applied. An active noise control (ANC) method is providing to be an attractive alternative. The approach taken in this paper uses a numerical finite/boundary element method (FEM/BEM) that may be easilty adapted to arbitrary geometries. A double walled cylinder is modeled using commercially available software. The outer shell is modeled as an aluminum cylinder, similar to that of aircraft skins. The inner shell is modeled as a composite material representative of a lightweight, stiff trim panel. Two different inner shell materials are used. The first is representative of current trim structure, the second a much stiffer composite. The primary source is generated by an exterior acoustic monopole. Control fields are generated using normal force inputs to the inner cylindrical shell. A linear least mean square (LMS) algorithm is used to determine amplitudes of control forces that minimize the interior acoustic field. Coupling of acoustic and structural modes and noise reductions are discussed for each of the inner shell materials.

  7. DEVELOPMENT OF CALCULATING MODEL APPLICABLE FOR CYLINDER WALL DYNAMIC HEAT TRANSFER

    Institute of Scientific and Technical Information of China (English)

    ZHONG Minjun; SHI Tielin

    2007-01-01

    In the calculation of submarine air conditioning load of the early stage, the obtained heat is regarded as cooling load. The confusion of the two words causing the cooling load figured out is abnormally high, and the change of air conditioning cooling load can not be indicated. In accordance with submarine structure and heat transfer characteristics of its inner components, Laplace transformation to heat conduction differential equation of cylinder wall is carried out. The dynamic calculation of submarine conditioning load based on this model is also conducted, and the results of calculation are compared with those of static cooling load calculation. It is concluded that the dynamic cooling load calculation methods can illustrate the change of submarine air conditioning cooling load more accurate than the static one.

  8. Performance analysis of greenhouse dryer by using insulated north-wall under natural convection mode

    Directory of Open Access Journals (Sweden)

    Prashant Singh Chauhan

    2016-11-01

    Full Text Available A prototype north wall insulated greenhouse dryer has been fabricated and tested in no-load conditions under natural convection mode. Experimentation has been conducted in two different cases. Case-I is when solar collector placed inside the dryer and Case-II is North wall insulated greenhouse dryer without solar collector. Coefficient of performance, heat utilisation factor, convective heat transfer coefficient and coefficient of diffusivity have been evaluated in thermal performance analysis. The difference of the highest convective heat transfer coefficient of both cases is 29.094W/m2°C which is showing the effectiveness of insulated north wall and solar collector. The maximum coefficient of diffusivity (0.0827 was achieved during the third day of experiment in Case-II. The inside room temperature of wall insulated greenhouse dryer for Case-I is 4.11%, 5.08 % and 11.61 % higher than the Case-II during the day 1, day 2 and day 3 respectively. This result is also showing the effectiveness of solar collector and insulated north wall. The highest heat utilisation factor (0.616 is obtained during the second day for Case-I while for Case-II it is 0.769 during the third day of experimentation. Maximum coefficient of performance achieved is 0.892 during the third day of the experiment for Case-I whereas 0.953 is obtained on the first day of experimentation for Case-II.

  9. NUMERICAL SIMULATION OF AN OSCILLATING FLOW PAST A CIRCULAR CYLINDER IN THE VICINITY OF A PLANE WALL

    Institute of Scientific and Technical Information of China (English)

    SHAH Syed Bilai Hussain; LU Xi-yun

    2008-01-01

    Oscillating flow around a circular cylinder in the vicinity of a plane wall was investigated by solving the two-dimensional incompressible Navier-Stokes equations with a finite element Galarkin residual method. The effect of the gap G/D between the cylinder surface and the wall on the flow behavior was studied. For the case of G/D ≤ 0.25, the periodicity in the flow is attributed to both the outer shear layer instability and the oscillating frequency. As G/D > 0.25, vortex shedding occurs and the periodicity in the flow is mainly due to the competition of the oscillating frequency and the vortex shedding frequency from an isolated stationary cylinder.

  10. Moisture conditions for organic and mineral-based insulation products used in exterior walls and attics in traditional Danish dwellings

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn

    2005-01-01

    and attics were insulated with cellulose, flax and mineral wool as thermal insulation. Exterior walls were constructed without PE vapour barriers while ceilings were constructed with PE vapour barriers. The investigation showed that for a typical Danish way to construct dwellings neither the moisture......On a Danish housing estate moisture sensors were installed in dwellings, partly in exterior walls and partly in attics. At each location sensors were installed within the insulation at two positions, one facing the outer cold side and the other facing the inner warm side. The exterior walls...... conditions in walls nor attics provide a risk or concern of mould growth in the thermal insulation....

  11. Internal Insulation of Masonry Walls with Wooden Floor Beams in Northern Humid Climate

    DEFF Research Database (Denmark)

    Morelli, Martin; Scheffler, Gregor Albrecht; Nielsen, Toke Rammer

    2010-01-01

    Multi-story buildings in Denmark from 1850–1950 are built with masonry walls and wooden floor beams. Large energy savings can be achieved by insulating the facades. Often interior insulation is the only possibility in order to keep the appearance of the external facade. The internal insulation...... reduces the drying potential of the wall, which might lead to moisture problems in the beam ends embedded in the masonry due to absorption of driving rain. This paper describes a solution to avoid the moisture problems and still achieve large energy savings. The thermal analyses are made in thermal...... simulation programs for two dimensions and three dimensions. The moisture analyses are made by a twodimensional simulation of the coupled heat, air, and moisture transport. The results show that leaving an uninsulated part of the wall above and below the floor division could solve the moisture problem...

  12. Online listening tests on sound insulation of walls

    DEFF Research Database (Denmark)

    Pedersen, Torben Holm; Antunes, Sonia; Rasmussen, Birgit

    2012-01-01

    As part of the COST Action TU0901 WG 2 activities a listening test was made on the annoyance potential of airborne noise from neighbours heard through walls. 22 assessors from 11 countries rated six simulated walls with four types of neighbour noise online at the assessor’s premises using the ISO....../TS 15666 annoyance scale. A simple “calibration” procedure based on adjusting a speech sample to natural level for approximate calibration was used. Dose-response curves for neighbour noise, i.e. the annoyance potential of neighbour noise heard on the receiving side of the walls as function of the A......-weighted levels or the loudness levels was found with high correlations between levels and annoyance. For the combination of the selected walls and noise types a high correlation was also found between the annoyance potential of the neighbour noise and the R’w-values for the simulated walls....

  13. Collapse Pressure Analysis of Transversely Isotropic Thick-Walled Cylinder Using Lebesgue Strain Measure and Transition Theory

    Directory of Open Access Journals (Sweden)

    A. K. Aggarwal

    2014-01-01

    Full Text Available The objective of this paper is to provide guidance for the design of the thick-walled cylinder made up of transversely isotropic material so that collapse of cylinder due to influence of internal and external pressure can be avoided. The concept of transition theory based on Lebesgue strain measure has been used to simplify the constitutive equations. Results have been analyzed theoretically and discussed numerically. From this analysis, it has been concluded that, under the influence of internal and external pressure, circular cylinder made up of transversely isotropic material (beryl is on the safer side of the design as compared to the cylinders made up of isotropic material (steel. This is because of the reason that percentage increase in effective pressure required for initial yielding to become fully plastic is high for beryl as compared to steel which leads to the idea of “stress saving” that reduces the possibility of collapse of thick-walled cylinder due to internal and external pressure.

  14. Analysis of Air Flow in the Ventilated Insulating Air Layer of the External Wall

    Science.gov (United States)

    Katunská, Jana; Bullová, Iveta; Špaková, Miroslava

    2016-12-01

    The paper deals with problems of impact of air flow in ventilated insulating air layer of the external wall on behaviour of thermal-technical parameters of the proposed external structure (according principles of STN 73 0549, which is not valid now), by comparing them in the calculation according to the valid STN standards, where air flow in the ventilated air layer is not taken into account, as well as by comparing them with behavior of thermal-technical parameters in the proposal of sandwich external wall with the contact heat insulation system without air cavity.

  15. Analytical solution for the pseudoelastic response of a shape memory alloy thick-walled cylinder under internal pressure

    Science.gov (United States)

    Tabesh, M.; Liu, B.; Boyd, J. G.; Lagoudas, D. C.

    2013-09-01

    Analytical solutions are derived for the isothermal pseudoelastic response of a shape memory alloy (SMA) thick-walled cylinder subjected to internal pressure. The Tresca transformation criterion and linear hardening are used. Equations are given for the radial and circumferential stresses, transformation strains and radial displacement at various steps of loading and unloading. A structural pressure-temperature phase diagram is provided for the cylinder, analogous to the stress-temperature phase diagram of SMA materials. Pressurization of an initially 100% austenitic cylinder causes the martensite to initially form at the inner radius. For a relatively thin-walled cylinder the transformation front reaches the outer radius before the transformation has completed at the inner radius, whereas for a thick-walled cylinder the transformation completes at the inner radius while there is still an outer ring of 100% austenite. For a given OD/ID ratio, a critical temperature is derived that stipulates which of these two cases occurs. An analytical result is provided for the pressure that will cause the transformation to complete at the inner radius. During unloading, the reverse transformation can start at either the inner or the outer surface of the cylinder and can propagate outward and then reverse its direction and propagate back to the inner surface. The effect of martensitic transformation on the structural yield strength due to plasticity is also investigated and it is shown that the pressure required to initiate yielding can be substantially decreased or increased depending on the temperature and the state of transformation achieved, even though the yield stress of the material is independent of temperature. Finally, the effectiveness of the Tresca transformation criterion to derive closed-form solutions for this problem is demonstrated by comparing with finite element solutions using the von Mises theory.

  16. Metallic Interface Emerging at Magnetic Domain Wall of Antiferromagnetic Insulator: Fate of Extinct Weyl Electrons

    Directory of Open Access Journals (Sweden)

    Youhei Yamaji

    2014-05-01

    Full Text Available Topological insulators, in contrast to ordinary semiconductors, accompany protected metallic surfaces described by Dirac-type fermions. Here, we theoretically show that another emergent two-dimensional metal embedded in the bulk insulator is realized at a magnetic domain wall. The domain wall has long been studied as an ingredient of both old-fashioned and leading-edge spintronics. The domain wall here, as an interface of seemingly trivial antiferromagnetic insulators, emergently realizes a functional interface preserved by zero modes with robust two-dimensional Fermi surfaces, where pyrochlore iridium oxides proposed to host the condensed-matter realization of Weyl fermions offer such examples at low temperatures. The existence of in-gap states that are pinned at domain walls, theoretically resembling spin or charge solitons in polyacetylene, and protected as the edges of hidden one-dimensional weak Chern insulators characterized by a zero-dimensional class-A topological invariant, solves experimental puzzles observed in R_{2}Ir_{2}O_{7} with rare-earth elements R. The domain wall realizes a novel quantum confinement of electrons and embosses a net uniform magnetization that enables magnetic control of electronic interface transports beyond the semiconductor paradigm.

  17. Modeling thermal performance of exterior walls retrofitted from insulation and modified laterite based bricks materials

    Science.gov (United States)

    Wati, Elvis; Meukam, Pierre; Damfeu, Jean Claude

    2017-06-01

    Uninsulated concrete block walls commonly found in tropical region have to be retrofitted to save energy. The thickness of insulation layer used can be reduced with the help of modified laterite based bricks layer (with the considerably lower thermal conductivity than that of concrete block layer) during the retrofit building fabrics. The aim of this study is to determine the optimum location and distribution of different materials. The investigation is carried out under steady periodic conditions under the climatic conditions of Garoua in Cameroon using a Simulink model constructed from H-Tools (the library of Simulink models). Results showed that for the continuous air-conditioned space, the best wall configuration from the maximum time lag, minimum decrement factor and peak cooling transmission load perspective, is dividing the insulation layer into two layers and placing one at the exterior surface and the other layer between the two different massive layers with the modified laterite based bricks layer at the interior surface. For intermittent cooling space, the best wall configuration from the minimum energy consumption depends on total insulation thickness. For the total insulation thickness less than 8 cm approximately, the best wall configuration is placing the half layer of insulation material at the interior surface and the other half between the two different massive layers with the modified earthen material at the exterior surface. Results also showed that, the optimum insulation thickness calculated from the yearly cooling transmission (estimated only during the occupied period) and some economic considerations slightly depends on the location of that insulation.

  18. Limit analysis of viscoplastic thick-walled cylinder and spherical shell under internal pressure using a strain gradient plasticity theory

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Plastic limit load of viscoplastic thick-walled cylinder and spherical shell subjected to internal pressure is investigated analytically using a strain gradient plastic-itv theory. As a result, the current solutions can capture the size effect at the micron scale. Numerical results show that the smaller the inner radius of the cylinder or spherical shell, the more significant the scale effects. Results also show that the size effect is more evident with increasing strain or strain-rate sensitivity index. The classical plastic-based solutions of the same problems are shown to be a special case of the present solution.

  19. Numerical simulation of design for cylinder wall considering of scavenging efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, S.; Ezumi, T.; Satoh, K. [Dept. of Mechanical Eng., Shibaura Inst. of Tech., Tokyo (Japan)

    2004-07-01

    The transformation of the cylinder is examined and analyzed the pressure and the temperature by means of the numerical analysis under the change of the scavenging efficiency. The change of the scavenging efficiency makes the temperature and the pressure change. The combustion temperature of the 2-cycle internal combustion engine that a lot of fuels may burn in the cylinder when the scavenging efficiency goes up. According to the scavenging efficiency, the temperature and the pressure is getting high. So the cylinder is transformed under the high temperature and the high pressure. The authors simulated the change of the temperature and the pressure in the cylinder. When the cylinder is designed, the engineer must know the change of the state in the cylinder. Then the change of the scavenging efficiency was simulated and examined. At the same time, the NO gas generated. The authors examined the transformation of the cylinder and simulated the NO generation. (orig.)

  20. Experimental study and advanced CFD simulation of fire safety performance of building external wall insulation system

    Directory of Open Access Journals (Sweden)

    Yan Zhenghua

    2013-11-01

    Full Text Available Large scale fire tests of building external wall insulation system were conducted. In the experiment, thermal-couples were mounted to measure the insulation system surface temperature and the gas temperature inside rooms at the second and third floors. Photos were also taken during the fire tests. The measurement provides information of the ignition and fire spread of the external insulation system which consists of surface protection layer, glass fibre net, bonding thin layer, anchor and the load bearing wall. Comprehensive simulations of the fire tests were carried out using an advanced CFD fire simulation software Simtec (Simulation of Thermal Engineering Complex [1, 2], which is now released by Simtec Soft Sweden, with the turbulent flow, turbulent combustion, thermal radiation, soot formation, convective heat transfer, the fully coupled three dimensional heat transfer inside solid materials, the ‘burn-out' of the surface protection layer and the pyrolysis of the insulation layer, etc, all computed. The simulation is compared with experimental measurement for validation. The simulation well captured the burning and fire spread of the external insulation wall.

  1. Trombe walls with nanoporous aerogel insulation applied to UK housing refurbishments

    Directory of Open Access Journals (Sweden)

    Mark Dowson

    2014-10-01

    Full Text Available There is an opportunity to improve the efficiency of passive Trombe walls and active solar air collectors by replacing their conventional glass covers with lightweight polycarbonate panels filled with nanoporous aerogel insulation. This study investigates the thermal performance, energy savings, and financial payback period of passive Aerogel Trombe walls applied to the existing UK housing stock. Using parametric modeling, a series of design guidance tables have been generated, providing estimates of the energy savings and overheating risk associated with applying areas of Trombe wall to four different house types across the UK built to six notional construction standards. Calculated energy savings range from 183 kWh/m2/year for an 8 m2 system retrofitted to a solid walled detached house to 62 kWh/m2/year for a 32 m2 system retrofitted to a super insulated flat. Predicted energy savings from Trombe walls up to 24 m2 are found to exceed the energy savings from external insulation across all house types and constructions. Small areas of Trombe wall can provide a useful energy contribution without creating a significant overheating risk. If larger areas are to be installed, then detailed calculations would be recommended to assess and mitigate potential overheating issues.

  2. Determination of optimum insulation thicknesses using economical analyse for exterior walls of buildings with different masses

    Directory of Open Access Journals (Sweden)

    Okan Kon

    2017-07-01

    Full Text Available In this study, five different cities were selected from the five climatic zones according to Turkish standard TS 825, and insulation thicknesses of exterior walls of sample buildings were calculated by using optimization. Vertical perforated bricks with density of 550 kg/m3 and 1000 kg/m3 were chosen within the study content. Glass wool, expanded polystyrene (XPS, extruded polystyrene (EPS were considered as insulation materials. Additionally, natural gas, coal, fuel oil and LPG were utilized as fuel for heating process while electricity was used for cooling.  Life cycle cost (LCC analysis and degree-day method were the approaches for optimum insulation thickness calculations. As a result, in case of usage vertical perforated bricks with density of 550 kg/m3 and 1000 kg/m3 resulted different values in between 0.005-0.007 m (5-7 mm in the optimum insulation thickness calculations under different insulation materials.  Minimum optimum insulation thickness was calculated in case XPS was preferred as insulation material, and the maximum one was calculated in case of using glass wool.

  3. A borehole stability study by newly designed laboratory tests on thick-walled hollow cylinders

    Directory of Open Access Journals (Sweden)

    S.S. Hashemi

    2015-10-01

    Full Text Available At several mineral exploration drilling sites in Australia, weakly consolidated formations mainly consist of sand particles that are poorly bonded by cementing agents such as clay, iron oxide cement or calcite. These formations are being encountered when drilling boreholes to the depth of up to 200 m. To study the behaviour of these materials, thick-walled hollow cylinder (TWHC and solid cylindrical synthetic specimens were designed and prepared by adding Portland cement and water to sand grains. The effects of different parameters such as water and cement contents, grain size distribution and mixture curing time on the characteristics of the samples were studied to identify the mixture closely resembling the formation at the drilling site. The Hoek triaxial cell was modified to allow the visual monitoring of grain debonding and borehole breakout processes during the laboratory tests. The results showed the significance of real-time visual monitoring in determining the initiation of the borehole breakout. The size-scale effect study on TWHC specimens revealed that with the increasing borehole size, the ductility of the specimen decreases, however, the axial and lateral stiffnesses of the TWHC specimen remain unchanged. Under different confining pressures the lateral strain at the initiation point of borehole breakout is considerably lower in a larger size borehole (20 mm compared to that in a smaller one (10 mm. Also, it was observed that the level of peak strength increment in TWHC specimens decreases with the increasing confining pressure.

  4. ELASTOPLASTIC ANALYSIS OF THICK-WALL CYLINDER CONSIDERING THE MATERIAL'S DILATANCY CHARACTER

    Institute of Scientific and Technical Information of China (English)

    江崎哲郎; 张铭; 竹下昭博; 三谷泰浩

    1995-01-01

    Impermeable bentonite or its mixtures have been proposed as candidate materials to be used in the geotechnical disposal of radioactive nuclear waste. These materials are filled in the space between a canister containing radioactive nuclear waste and an underground chamber to absorb the radionuclide emitting from the canister and simultaneously retard its migration accompanying the permeation of underground water to prevent the surrounding environment from pollution. On the basis of the established elastoplastic strain-hardening mechanical model considering the material's dilatancy character, the authors carry out the stress-strain analysis of a thick-wall cylinder in a plane strain state subjected to a pressure difference between internal and external pressures. The analysis may be expected to be a theoretical basis for developing a coupled shear and permeability test apparatus for conducting a permeability test along a sheared plane in a specimen. The apparatus will be used to study the effects of shear strain on the variation of geotechnical materials′ permeability coefficient in order to evaluate the influence of shear strain caused by nonuniform deformation and/or earthquake on the long-term safety of the disposal system of radioactive nuclear waste. The theoretical analysis methods in this paper can be directly spread to the analysis of the deformation and stability of tunnels or roadways driven in soft soils or high moisture-bearing soft rocks.

  5. STATIONARY PROBLEM OF MOISTURE-INDUCED ELASTICITY OF HETEROGENEOUS THICK-WALLED CYLINDERS

    Directory of Open Access Journals (Sweden)

    Andreev Vladimir Igorevich

    2012-10-01

    Full Text Available Many problems of identification of the stress-strain state against the background of the heat and mass transfer are solved through the application of constant (averaged values of mechanical properties (elastic modulus, Poisson's ratio and derivation of differential equations with constant coefficients. Due to irregular distribution of temperature and other factors of impact, including the moisture content, mechanical properties of many materials change significantly; therefore, the problems in question are solved within the framework of mechanics of heterogeneous bodies. In this paper, the authors solve the classical problem of the steady-state moisture-induced elasticity of a thick-walled cylinder by taking account of the changes in the value of the elastic modulus caused by the influence of moisture. In this case, the problem is reduced to a differential equation with variable coefficients, which makes the solution more complicated though more accurate. It is proven that due regard for the heterogeneity leads to a significant increase in stresses, if compared to the solution based on the mean values of the modulus of elasticity.

  6. High gradient insulator technology for the dielectric wall accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Sampayan, S.; Caporaso, G.; Carder, B. [and others

    1995-04-27

    Insulators composed of finely spaced alternating layers of dielectric and metal are thought to minimize secondary emission avalanche (SEA) growth. Most data to date was taken with small samples (order 10 cm{sup 2} area) in the absence of an ion or electron beam. The authors have begun long pulse (>1 {mu}s) high voltage testing of small hard seal samples. Further, they have performed short pulse (20 ns) high voltage testing of moderate scale bonded samples (order 100 cm{sup 2} area) in the presence of a 1 kA electron beam. Results thus far indicate a 1.0 to 4.0 increase in the breakdown electric field stress is possible with this technology.

  7. Numerical Simulation for Blast Analysis of Insulating Glass in a Curtain Wall

    Science.gov (United States)

    Deng, Rong-bing; Jin, Xian-long

    2010-04-01

    This article presents a three-dimensional numerical simulation method for blast response calculation of insulating glass in a curtain wall based on multi-material arbitrary Lagrangian-Eulerian (ALE) formulation and high-performance computer. The whole analytical model consists of explosion, air, curtain wall system, and ground. In particular, detailed components including insulating glass panels, aluminum column, silicone sealant, and other parts in the curtain wall are set up in terms of actual size and actual assembly. This model takes account of the coupling between blast and structure, nonlinear material behavior, brittle failure of glass material, and non-reflecting boundary definition. Final calculation has been performed on the Dawning 4000A supercomputer using the finite-element code LS-DYNA 971 MPP. The propagation of shock wave in air and blast-structure interaction is quite well estimated by numerical calculation. The damage regions of outer and inner glass are reproduced in the numerical simulations, which are in agreement with the experimental observations. The result provides a global understanding of insulating glass panels under blast loading in the curtain wall system. It may be generated to supplement experimental studies for developing appropriate design guidelines for curtain wall systems as well.

  8. An improved approach for the application of Trombe wall system to building construction with selective thermo-insulation facades

    Institute of Scientific and Technical Information of China (English)

    JI Jie; LUO ChengLong; SUN Wei; YU HanCheng; HE Wei; PEI Gang

    2009-01-01

    An improved Trombe wall is proposed to adapt to building construction with selective thermo-insula-tion facades (internal and cavity wall insulation, but not external wall insulation system). The case study is conducted in Xining, Capital city of Qinghai province in China, where the general building fa-cades are mostly selective thermo-insulation fagades to fight against the severe cold. A numerical analysis is undertaken to show the effects on the improvement of the building's thermal environment by comparing the improved Trombe wall system with the classical Trombe wall system. The operating efficiency of the improved Trombe wall can be up to 33.85%, an increase of 56%. The results show that the improved Trombe wall works more effectively than the classical Trombe wall system in utilizing solar energy for the sample building.

  9. Construction Guidelines for High R-Value Walls without Exterior Rigid Insulation

    Energy Technology Data Exchange (ETDEWEB)

    Arena, Lois B. [Steven Winter Associates, Inc., Norwalk, CT (United States). Consortium for Advanced Residential Buildings

    2016-07-13

    High-R wall assemblies (R-40 and above) are gaining popularity in the market due to programs like the DOE's Zero Energy Ready Home program, Passive House (PH), Net Zero Energy Home (NZEH) challenges in several states, and highly incentivized retrofit programs. In response to this demand, several builders have successfully used 'double wall' systems to more practically achieve higher R-values in thicker, framed walls. To builders of conventional stick-framed homes, often one of the most appealing features of double wall systems is that there are very few new exterior details. Exterior sheathing, structural bracing, house wrap or building paper, window and door flashing, and siding attachment are usually identical to good details in conventional framed wall systems. The information presented in this guide is intended to reduce the risk of failure in these types of assemblies, increase durability, and result in a reduction of material brought to landfills due to failures and resulting decay. While this document focuses on double wall framing techniques, the majority of the information on how to properly construct and finish high R-value assemblies is applicable to all wall assemblies that do not have foam insulation installed on the exterior of the structural sheathing. The techniques presented have been shown through field studies to reduce the likelihood of mold growth and moisture related damage and are intended for builders, framing contractors, architects, and consultants involved in designing and building super insulated homes.

  10. USAGE OF MICRO-MODULAR HEAT-INSULATION LAYER IN STRUCTURES OF WALL PANELS

    Directory of Open Access Journals (Sweden)

    V. D. Sizov

    2014-01-01

    Full Text Available The paper presents an analysis of requirements to existing heat-insulation layers in enclosure structures of wall panels has been carried out, a general principles on development of thermal insulation systems, substantiation on the necessity to develop a new wall panel design with improved thermal characteristics. The proposed design of the wall panel differs from the existing one in the fact that its external layer is made of protective sheets being perforated in their top and bottom parts with perforated aluminum foil layer placed on them. Air layer performs function of one of thermal insulation layers, and the second layer is made up in the form of several micro-modular sub-layers which are divided by perforated aluminum foil and a grid. An inner concrete layer is also separated from micro-modular layers by aluminum foil. Protective sheets and the grid can be made of aluminum or polyethylene.The arrangement of hollow micro-modular cells in the zone of negative temperatures prevents condensate accumulation. The arrangement of the perforated aluminum foil layers between micro- modular layers leads to increase in thermal resistance of the panel due to decrease of a radiant component in presence of several screens and does not interfere with a vapor permeability of thermal insulation layers from micro-modules. At the same time placement of a non-perforated foil layer on an inside panel layer interferes with penetration of water vapor from rooms in micro-modular thermal insulation layers.Technological principles lie in the arrangement of perforation slots in the top and bottom zones of protective sheets that allows to delete excess moisture from thermal insulation layers and air layer and also leads to improvement of thermo-technical characteristics, durability and reliability in construction operation as a whole. The executed calculations of heat and humidity fields in external enclosure structures confirm advantages of the presented technical

  11. Physical Modeling and Parametric Study on Two-Degree-of-Freedom VIV of A Cylinder near Rigid Wall

    Institute of Scientific and Technical Information of China (English)

    YANG Bing; GAO Fu-ping; LI Dong-hui; WU Ying-xiang

    2009-01-01

    Unlike most previous studies on the transverse vortex-induced vibration(VIV) of a cylinder mainly under the wallfree condition (Williamson & Govardhan,2004),this paper experimentally investigates the vortex-induced vibration of a cylinder with two degrees of freedom near a rigid wall exposed to steady flow.The amplitude and frequency responses of the cylinder are discussed.The lee wake flow patterns of the cylinder undergoing VIV were visualized by employing the hydrogen bubble technique.The effects of the gap-to-diameter ratio (e0/D) and the mass ratio on the vibration amplitude and frequency are analyzed.Comparisons of VIV response of the cylinder are made between one degree (only transverse) and two degrees of freedom (streamwise and transverse) and those between the present study and previous ones.The experimental observation indicates that there are two types of streamwise vibration,i.e.the first streamwise vibration (FSV) with small amplitude and the second streamwise vibration (SSV) which coexists with transverse vibration.The vortex shedding pattem for the FSV is approximately symmetric and that for the SSV is alternate.The first streamwise vibration tends to disappear with the decrease of e0/D.For the case of large gap-to-diameter ratios (e.g.e0/D = 0.54~1.58),the maximum amplitudes of the second streamwise vibration and transverse one increase with the increasing gapto-diameter ratio.But for the case of small gap-to-diameter ratios (e.g.e0/D = 0.16,0.23),the vibration amplitude of the cylinder increases slowly at the initial stage (i.e.at small reduced velocity V,),and across the maximum amplitude it decreases quickly at the last stage (i.e.at large Vr).Within the range ofthe examined small mass ratio (m<4),both streamwise and transverse vibration amplitude of the cylinder decrease with the increase of mass ratio for the fixed value of V,.The vibration range (in terms of Vr ) tends to widen with the decrease of the mass ratio.In the second streamwise

  12. Convective heat transfer from a heated elliptic cylinder at uniform wall temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kaprawi, S.; Santoso, Dyos [Mechanical Department of Sriwijaya University, Jl. Raya Palembang-Prabumulih Km. 32 Inderalaya 50062 Ogan Ilir (Indonesia)

    2013-07-01

    This study is carried out to analyse the convective heat transfer from a circular and an elliptic cylinders to air. Both circular and elliptic cylinders have the same cross section. The aspect ratio of cylinders range 0-1 are studied. The implicit scheme of the finite difference is applied to obtain the discretized equations of hydrodynamic and thermal problem. The Choleski method is used to solve the discretized hydrodynamic equation and the iteration method is applied to solve the discretized thermal equation. The circular cylinder has the aspect ratio equal to unity while the elliptical cylinder has the aspect ratio less than unity by reducing the minor axis and increasing the major axis to obtain the same cross section as circular cylinder. The results of the calculations show that the skin friction change significantly, but in contrast with the elliptical cylinders have greater convection heat transfer than that of circular cylinder. Some results of calculations are compared to the analytical solutions given by the previous authors.

  13. Thermal resistances of air in cavity walls and their effect upon the thermal insulation performance

    Energy Technology Data Exchange (ETDEWEB)

    Bekkouche, S.M.A.; Cherier, M.K.; Hamdani, M.; Benamrane, N. [Application of Renewable Energies in Arid and Semi Arid Environments /Applied Research Unit on Renewable Energies/ EPST Development Center of Renewable Energies, URAER and B.P. 88, ZI, Gart Taam Ghardaia (Algeria); Benouaz, T. [University of Tlemcen, BP. 119, Tlemcen R.p. 13000 (Algeria); Yaiche, M.R. [Development Center of Renewable Energies, CDER and B.P 62, 16340, Route de l' Observatoire, Bouzareah, Algiers (Algeria)

    2013-07-01

    The optimum thickness in cavity walls in buildings is determined under steady conditions; the heat transfer has been calculated according to ISO 15099:2003. Two forms of masonry units are investigated to conclude the advantage of high thermal emissivity. The paper presents also some results from a study of the thermal insulation performance of air cavities bounded by thin reflective material layer 'eta = 0.05'. The results show that the most economical cavity configuration depends on the thermal emissivity and the insulation material used.

  14. Thermal resistances of air in cavity walls and their effect upon the thermal insulation performance

    Directory of Open Access Journals (Sweden)

    S. M. A. Bekkouche, T. Benouaz, M. K. Cherier, M. Hamdani, M.R. Yaiche, N. Benamrane

    2013-01-01

    Full Text Available The optimum thickness in cavity walls in buildings is determined under steady conditions; the heat transfer has been calculated according to ISO 15099:2003. Two forms of masonry units are investigated to conclude the advantage of high thermal emissivity. The paper presents also some results from a study of the thermal insulation performance of air cavities bounded by thin reflective material layer "ε = 0.05". The results show that the most economical cavity configuration depends on the thermal emissivity and the insulation material used.

  15. Composite Behavior of Insulated Concrete Sandwich Wall Panels Subjected to Wind Pressure and Suction

    Directory of Open Access Journals (Sweden)

    Insub Choi

    2015-03-01

    Full Text Available A full-scale experimental test was conducted to analyze the composite behavior of insulated concrete sandwich wall panels (ICSWPs subjected to wind pressure and suction. The experimental program was composed of three groups of ICSWP specimens, each with a different type of insulation and number of glass-fiber-reinforced polymer (GFRP shear grids. The degree of composite action of each specimen was analyzed according to the load direction, type of the insulation, and number of GFRP shear grids by comparing the theoretical and experimental values. The failure modes of the ICSWPs were compared to investigate the effect of bonds according to the load direction and type of insulation. Bonds based on insulation absorptiveness were effective to result in the composite behavior of ICSWP under positive loading tests only, while bonds based on insulation surface roughness were effective under both positive and negative loading tests. Therefore, the composite behavior based on surface roughness can be applied to the calculation of the design strength of ICSWPs with continuous GFRP shear connectors.

  16. Composite Behavior of Insulated Concrete Sandwich Wall Panels Subjected to Wind Pressure and Suction

    Science.gov (United States)

    Choi, Insub; Kim, JunHee; Kim, Ho-Ryong

    2015-01-01

    A full-scale experimental test was conducted to analyze the composite behavior of insulated concrete sandwich wall panels (ICSWPs) subjected to wind pressure and suction. The experimental program was composed of three groups of ICSWP specimens, each with a different type of insulation and number of glass-fiber-reinforced polymer (GFRP) shear grids. The degree of composite action of each specimen was analyzed according to the load direction, type of the insulation, and number of GFRP shear grids by comparing the theoretical and experimental values. The failure modes of the ICSWPs were compared to investigate the effect of bonds according to the load direction and type of insulation. Bonds based on insulation absorptiveness were effective to result in the composite behavior of ICSWP under positive loading tests only, while bonds based on insulation surface roughness were effective under both positive and negative loading tests. Therefore, the composite behavior based on surface roughness can be applied to the calculation of the design strength of ICSWPs with continuous GFRP shear connectors. PMID:28788001

  17. Optimum Insulation Thickness for Walls and Roofs for Reducing Peak Cooling Loads in Residential Buildings in Lahore

    Directory of Open Access Journals (Sweden)

    SIBGHA SIDDIQUE SIDDIQUE

    2016-10-01

    Full Text Available Thermal insulation is the most effective energy saving measure for cooling in buildings. Therefore, the main subject of many engineering investigations is the selection and determination of the optimum insulation thickness. In the present study, the optimum insulation thickness on external walls and roofs is determined based on the peak cooling loads for an existing residential building in Lahore, Pakistan. Autodesk® Revit 2013 is used for the analysis of the building and determination of the peak cooling loads. The analysis shows that the optimum insulation thickness to reduce peak cooling loads up to 40.1% is 1 inch for external walls and roof respectively.

  18. EVALUATION OF THERMAL INSULATION FOR THREE DIFFERENT MATERIALS USED IN CONSTRUCTION AND COMPLETION OF EXTERNAL WALLS

    Directory of Open Access Journals (Sweden)

    Marcio Carlos Navroski

    2010-05-01

    Full Text Available Summers increasingly hot are bringing large thermal problems within homes and businesses, leading to increased demand for installation of air conditioners and the consequent high energy consumption. Constructions with thermal insulation on its external walls thatcould reduce energy use or even supply the use of such equipment. Due to these factors the present study was to evaluate the insulation in three boxes built with different materials, one made of wooden boards with plain walls, and two built with plywood, wall insulation andinterior walls filled with rice husk and Styrofoam®. The boxes were built after placed in drying oven at 40 °C, then noted the temperature inside the same interval every five minutes using a digital thermometer. The box with inner Styrofoam® showed the lowest variation among the three evaluated, followed by the box of rice husk. These two materials also showed good thermal initial, unlike the box built only with wood, which showed a large interiorheating, lay in a drying oven.

  19. Steady state theoretical model of fired clay hollow bricks for enhanced external wall thermal insulation

    Energy Technology Data Exchange (ETDEWEB)

    Bouchair, Ammar [Laboratoire de Recherche Cadre Bati et Environnement, Departement d' Architecture, Faculte des Sciences de l' Ingenieur, Universite de Jijel, BP 98 Ouled Aissa, Jijel 18000 (Algeria)

    2008-10-15

    This paper proposes a theoretical model to study the steady state thermal behavior of fired clay hollow bricks for enhanced external wall thermal insulation. The study aims at the development of new materials and structural components with good thermal material properties, with respect to energy saving and ecological design. Thermal insulation capacity of two external walls of different thicknesses, constructed of locally produced bricks, is studied. The basic brick units used for the investigation are small-size bricks with eight equal cavities or recesses and big-size bricks with twelve equal recesses. Their recesses configuration has been varied to perform the assessment. The insulation materials injected within brick recesses during the assessment are granulated cork and expanded polystyrene. The improvement in the thermal performance of the walls will be the result of optimization among the various factors such as brick cavity configurations, integration of insulation within brick recesses and the cavity surface emissivities. So emphasis is given to the study of the impact of these factors singly or in combination on the overall thermal resistance of walls in order to find out the best design solutions to maximize their thermal insulation capacity. Computer modeling and calculations performed, for steady state conditions, show that the increase in hollow brick cavity height contributes to the improvement of the overall thermal resistance of the order of 18-20%. The improvement could significantly increase to the range of 88.64% and 93.33%, if the bricks used are injected with the insulating material. If the cavity surface emissivities are lowered to 0.3, the improvement will be 72.73-78.33%. The results have also shown that replacing the cork by expanded polystyrene (EPS), having lower thermal conductivity, would not improve significantly the overall thermal resistance. This improvement is 9.08% for a wall of small-size bricks having configuration BS2CV and 8

  20. HEAT INSULATING LIME DRY MORTARS FOR FINISHING OF WALLS MADE OF FOAM CONCRETE

    Directory of Open Access Journals (Sweden)

    Loganina Valentina Ivanovna

    2016-05-01

    Full Text Available Different aerated mortars are used for pargeting of walls made of aerated concrete. Though the regulatory documents don’t specify the dependence of plaster density from the density grade of gas-concrete blocks. In case of facing of gas-concrete blocks with the grade D500 using plaster mortars with the density 1400…1600 km/m3 there occurs a dismatch in the values of thermal insulation and vapor permeability of the plaster and base. The authors suggest using dry mortars for finishing of gas-concrete block of the grades D500 и D600, which allow obtaining facing thermal insulating coatings. The efficiency of using four different high-porous additives in the lime dry mortar was compared. They were: hollow glass microspheres, aluminosilicate ash microspheres, expanded vermiculite sand, expanded pearlitic sand. The high efficiency of hollow glass microspheres in heat insulating finishing mortars compared to other fillers is proved.

  1. PRESSURE DISTRIBUTION ON THE WALL OF THE INNER CYLINDER RECIPROCATING AXIALLY TO THE UNSTEADY FLOW OF VISCOELASTIC FLUID IN ECCENTRIC ANNULUS

    Institute of Scientific and Technical Information of China (English)

    WANG Yan; CUI Hai-qing; YANG Yuan-jian; GUO Jun-hui; LI Nan

    2006-01-01

    In this article, the governing equations for the unsteady flow of viscoelastic fluid in the eccentric annulus with the inner cylinder reciprocating axially and the expression of the pressure distribution on the wall of the inner cylinder of the annulus are established and derived, respectively, under the bipolar coordinate system.The equations and the expression are solved and calculated numerically using the finite difference method, respectively.The curves of the pressure distribution on the wall of the inner cylinder of the aqueous solution of Hydrolyzed Polyacrylamide (HPAM) are plotted and the influences of annular eccentricity, stroke, and stroke frequency on the pressure distribution are analyzed.

  2. Unsteady mixed convection flow from a slender cylinder due to impulsive change in wall velocity and temperature

    Directory of Open Access Journals (Sweden)

    Patil P.M.

    2013-01-01

    Full Text Available An unsteady mixed convection flow of a viscous incompressible fluid over a non-permeable linear stretching vertical slender cylinder is considered to investigate the combined effects of buoyancy force and thermal diffusion. It is assumed that the slender cylinder is in line with the flow. The unsteadiness in the flow and temperature fields is caused due to the impulsive change in the wall velocity and wall temperature of linearly stretching vertical slender cylinder. The effect of surface curvature is also taken into account, particularly for the applications as wire and fiber drawing where exact predictions are expected. The governing boundary layer equations are transformed into a non-dimensional form by a group of non-similar transformations. The resulting system of coupled non-linear partial differential equations is solved by an implicit finite difference scheme in combination with the quasi-linearization technique. Numerical computations are performed to understand the physical situations of linear stretching surface for different values of parameters to display the velocity and temperature profiles graphically. The numerical results for the local skin-friction coefficient and local Nusselt number are also presented. Present results are compared with previously published work and are found to be in excellent agreement.

  3. The influence of ventilated façade on sound insulation properties of envelope walls

    Directory of Open Access Journals (Sweden)

    Fišarová Zuzana

    2017-01-01

    Full Text Available Presented article deals with sound insulation properties of timber structures’ envelope walls. Particularly, the influence of heavy board ventilated façade on laboratory airborne sound insulation R and Rw in dB was studied. The installation method and gaps between façade boards can cause building defects originating in overrating the influence of ventilated cladding on envelope wall acoustic parameters. Real constructions were built for the experimental purposes and measurements, one with gaps between boards and one with simply eliminated gaps for mutual comparison. The results obtained were processed to make tables and graphs and to derive recommendations for the design of this type of constructions involving the general installation method of façade boards. Detailed results are depicted in conclusions.

  4. Strain Induced Insulator-Metal Transition in Single Wall Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    丁建文; 颜晓红; 刘超平; 唐娜斯

    2004-01-01

    In terms of a single-π orbital model, an analytical expression of the lowest-lying conduction-band and the highestlying valence-band is derived for single wall carbon nanotubes under both the uniaxial and torsional strains. We observe not only semiconductor-metal transitions in primary metallic tubes, but also insulator-metal transitions in semiconducting tubes. Additionally, an indirect transition of electrons and a quantized electron-resonance have been expected in optical spectrum experiments of the nanotubes.

  5. Hydrodynamic performance of combined cylinders structure with dual arc-shaped porous outer walls

    Science.gov (United States)

    Lin, Gao; Liu, Jun

    2012-11-01

    This study examines the hydrodynamic performance of short-crested wave interaction with a new porous cylindrical structure by using the scaled boundary finite element method (SBFEM), which is a semi-analytical technique combining the advantages of the finite element method and the boundary element method and with its own special features as well. The cylindrical structure consists of dual arc-shaped porous outer cylinders circumscribing an impermeable inner cylinder. A central feature of the newly extended method is that two virtual outer cylinders extending the arc-shaped porous outer cylinders with the same centre are introduced and variable porous-effect parameters are also introduced for the two virtual cylinders, so that the final SBFEM equation still can be handled in a closed-form analytical manner in the radial direction and by a finite element approximation in the circumferential direction. The entire computational domain is divided into two bounded and one unbounded domains, and a variational principle formulation is used to derive the SBFEM equation in each sub-domain. The velocity potential in bounded and unbounded domains is formulated using sets of Bessel and Hankel functions respectively, and the unknown coefficients are determined from the matching conditions. The results of numerical verification show that the approach discretises only the outermost virtual cylinder with surface finite-elements and fewer elements are required to obtain very accurate results. Influences of the incident wave parameters and structural configurations on the hydrodynamics are examined.

  6. Setting of loose-fill insulation materials in walls; Saetningsfri indblaesning af loesfyldsisolering i vaegge

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, T.V.

    2001-07-01

    The report describes material behaviour, which significantly influences the settling of loose-fill insulation materials. The specific application presented here is loose-fill insulation material injected in walls as thermal insulation. The physical formulation of the issue to be discussed is that the mass is kept in position in the cavity by frictional forces, which counteracts the settling but complicates injection. The purpose of this study is to investigate whether there is a possibility that decreased friction will be able to release settling. Cellulose loose-fill material injected in a 0.1 m thick and 1 m wide gypsum wall with a minimum density of 48 kg/m3 was found not to settle if kept at a constant relative humidity, RH 50 %. A minimum density of 53 kg/m3 is necessary if the thickness of the wall is increased from 0.1 m to 0.3 m. If changing the constant environment from RH 50 % to RH 80 % a minimum density of 63 kg/m3 is necessary. Furthermore, results so far show that cellulose loose-fill material spread on the attic floor will have a density after settling of 48 kg /M3 for a constant RH 50 %, corresponding to 43 kg/m3 dry material. The results were found by using a model and tests. (au)

  7. A nondestructive method for diagnosis of insulated building walls using infrared thermography in real situation

    Science.gov (United States)

    Larbi Youcef, Mohamed H. A.; Mazioud, Atef; Bremond, Pierre; Ibos, Laurent; Candau, Yves; Piro, Michel; Filloux, Alain

    2008-03-01

    In order to provide a method to control conformity of insulation of buildings after restoration, Protomeres project was launched under Prebat 2005 program. This work deals with the development of an experimental protocol for the diagnostic of multi-layered insulated building walls. In a previous study, a test bench was set up in order to measure front and back side temperatures of standard panels compounded of 1cm of plaster and various thicknesses of polystyrene. The panels considered have insulation thicknesses of 2, 6 and 10cm. In the present work, the panels are fixed on walls in laboratory to test real situations in constructions. The front side is painted in standardized black color and heated by two halogen lamps of 500W. A CEDIP Jade Long wave infrared camera and thermocouples are used to carry out temperature measurements during an exposure time and subsequent cooling. In a second time, a one dimensional model based on thermal quadruples and Laplace transforms was developed under Matlab environment. This model simulates a three-layered wall with a blade of air between polystyrene and concrete. Finally, a method of identification of physical parameters is implemented by performing least square minimization based on Levenberg-Marquardt method. The experimental measurements are compared to theoretical results and by minimization we obtain thermal conductivity and diffusivity as well as thickness of the two layers.

  8. Insulator

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Isao; Ikami, Toshiichi.

    1990-09-17

    The insulating properties of transmission line insulators are reduced when the insulator becomes contaminated. Such contamination is promoted by the adherence of rainwater including dusts and/or absorbing of dusts and gas when the insulated surface is wetted with rainwater. It is known to treat insulators with water repellent compounds to avoid this problem, but known treatments have certain disadvantages such as loss of water repellency in a short time. An object of this invention is to overcome these disadvantages and to provide an insulator having a high usefulness and excellent water repellency which can be easily treated and maintained over a long period of time. It has been found that if a glass layer itself forming the surface of the insulator has water repellent properties, the water repellency of the insulator surface is not lost. According to the invention, the glassy surface is treated with silane or silazane to provide a surface layer of the proper water repellency. The insulator surface may be preferably treated in such a manner that the insulator is immersed in a bath of silane or silazane. Experiments are described to illustrate the performance of insulators treated according to the invention in comparison to non-treated insulators. 1 fig., 1 tab.

  9. Measure Guideline. Wall Air Sealing and Insulation Methods in Existing Homes; An Overview of Opportunity and Process

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, S. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Stephenson, R. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States)

    2012-09-01

    This guide provides renovators and retrofit contractors an overview of considerations when including wall air sealing and insulation in an energy retrofit project. It also outlines the potential project risks, various materials for insulating, possible field inspections needed, installation procedures, as well as the benefits and drawbacks.

  10. Moisture conditions for organic and mineral-based insulation products used in exterior walls and attics in traditional Danish dwellings

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn

    2005-01-01

    and attics were insulated with cellulose, flax and mineral wool as thermal insulation. Exterior walls were constructed without PE vapour barriers while ceilings were constructed with PE vapour barriers. The investigation showed that for a typical Danish way to construct dwellings neither the moisture...

  11. Construction Guidelines for High R-Value Walls without Exterior Rigid Insulation

    Energy Technology Data Exchange (ETDEWEB)

    Arena, Lois B. [Steven Winter Associates, Inc., Norwalk, CT (United States). Consortium for Advanced Residential Buildings (CARB)

    2016-07-13

    High R-value wall assemblies (R-40 and above) are gaining popularity in the market due to programs such as the U.S. Department of Energy Zero Energy Ready Home program, Passive House, Net Zero Energy Home challenges in several states, and highly incentivized retrofit programs. In response to this demand, several builders have successfully used double-wall systems to achieve higher R-values in thicker, framed walls. To builders of conventional stick-framed homes, often one of the most appealing features of double-wall systems is that there are very few new exterior details. Exterior sheathings, structural bracings, house wraps or building paper, window and door flashings, and siding attachments are usually identical to good details in conventional framed-wall systems. However, although the details in double-wall systems are very similar to those in conventional stick framing, there is sometimes less room for error. Several studies have confirmed colder temperatures of exterior sheathing in high R-value wall assemblies that do not have exterior rigid foam insulation. These colder temperatures can lead to increased chances for condensation from air exfiltration, and they have the potential to result in moisture-related problems (Straube and Smegal 2009, Arena 2014, Ueno 2015). The information presented in this guide is intended to reduce the risk of failure in these types of assemblies, increase durability, and reduce material brought to landfills due to failures and resulting decay. Although this document focuses on double-wall framing techniques, the majority of the information about how to properly construct and finish high R-value assemblies is applicable to all wall assemblies that do not have foam insulation installed on the exterior of the structural sheathing. The techniques presented have been shown through field studies to reduce the likelihood of mold growth and moisture-related damage and are intended for builders, framing contractors, architects, and

  12. dc and ac magnetic properties of thin-walled Nb cylinders with and without a row of antidots.

    Science.gov (United States)

    Tsindlekht, M I; Genkin, V M; Felner, I; Zeides, F; Katz, N; Gazi, Š; Chromik, Š; Dobrovolskiy, O V; Sachser, R; Huth, M

    2016-06-01

    dc and ac magnetic properties of two thin-walled superconducting Nb cylinders with a rectangular cross-section are reported. Magnetization curves and the ac response were studied on as-prepared and patterned samples in magnetic fields parallel to the cylinder axis. A row of micron-sized antidots (holes) was made in the film along the cylinder axis. Avalanche-like jumps of the magnetization are observed for both samples at low temperatures for magnetic fields not only above H c1, but in fields lower than H c1 in the vortex-free region. The positions of the jumps are not reproducible and they change from one experiment to another, resembling vortex lattice instabilities usually observed for magnetic fields larger than H c1. At temperatures above [Formula: see text] and [Formula: see text] the magnetization curves become smooth for the patterned and the as-prepared samples, respectively. The magnetization curve of a reference planar Nb film in the parallel field geometry does not exhibit jumps in the entire range of accessible temperatures. The ac response was measured in constant and swept dc magnetic field modes. Experiment shows that ac losses at low magnetic fields in a swept field mode are smaller for the patterned sample. For both samples the shapes of the field dependences of losses and the amplitude of the third harmonic are the same in constant and swept field near H c3. This similarity does not exist at low fields in a swept mode.

  13. Thermal balance of a wall with PCM-enhanced thermal insulation

    Energy Technology Data Exchange (ETDEWEB)

    Kosny, Jan [ORNL; Kossecka, Elizabeth [Institute of Fundamental Technological Research, Polish Academy of Sciences; Williams, Teresa [ORNL

    2010-01-01

    ABSTRACT: PCM insulation mixtures function as lightweight thermal mass components. It is expected that these types of dynamic insulation systems will contribute to the objective of reducing energy use in buildings. In this paper, dynamic thermal properties of a material in which phase hange occurs are analyzed, using the temperature-dependent specific heat model. Integral formula for the total heat flow in finite time interval, across the surface of a slab of the phase change material, was derived. Simulations have been performed to analyze heat transfer through a light-weight wall assembly with PCM-enhanced insulation, in different external climate thermal conditions. Results of simulations indicate that for cyclic processes, the effect of PCM in an insulation layer results rather in time shifting of the heat flux extreme values than in reduction of the total heat flow. The heat gains maxima, resulting in high cooling loads, are shifted in time by about two hours and reduced about 15% to 30% for not very high external sol-air temperatures.

  14. A comparative study on optimum insulation thickness of walls and energy savings in equatorial and tropical climate

    Directory of Open Access Journals (Sweden)

    Modeste Kameni Nematchoua

    2017-06-01

    Full Text Available The increase outdoor temperature acts directly on the indoor climate of buildings. In Cameroon, the energy consumption demand in the buildings sector has been rapidly increasing in recent years; so well that energy supply does not always satisfy demand. Thermal insulation technology can be one of the leading methods for reducing energy consumption in these new buildings. However, choosing the thickness of the insulation material often causes high insulation costs. In the present study, the optimum insulation thickness, energy saving and payback period were calculated for buildings in Yaoundé and Garoua cities, located in two climatic regions in Cameroon. The economic model including the cost of insulation material and the present value of energy consumption and the cost over a life time of 22 years of the building, were used to find the optimum insulation thickness, energy saving, and payback period. Materials that extruded polystyrene were chosen and used for two typical wall structures (concrete block (HCB and compressed stabilized earth block wall (CSEB. The early cooling transmission loads, according to wall orientations and percentage of radiation blocked were calculated using the explicit finite-difference method under steady periodic conditions. As a result, it was found that the west- and east-facing walls are the least favourite in the cooling season, whereas the south and north orientations are the most economical. Although wall orientation had a significant effect on the optimum insulation thickness, it had a more significant effect on energy savings. In equatorial region (Yaoundé, for south orientation, the optimum insulation thickness was 0.08 m for an energy savings of 51.69 $/m2. Meanwhile, in tropical region (Garoua, for north orientation, the optimum insulation thickness was 0.11 m for an energy savings of 97.82 $/m2.

  15. A nondestructive method for diagnostic of insulated building walls using infrared thermography

    Science.gov (United States)

    Larbi Youcef, Mohamed H. A.; Mazioud, Atef; Bremond, Pierre; Ibos, Laurent; Candau, Yves; Piro, Michel; Filloux, Alain

    2007-04-01

    This work deals with the development of an experimental protocol for the diagnostic of multi-layered insulated building walls. First, a test bench is set up in order to measure front and back sides temperatures of standard panels. The panels considered have insulation thicknesses of 2, 6 and 10cm. The front side is heated by two halogen lamps of 500W. A CEDIP Jade Long wave infrared camera and thermocouples are used to carry out temperature measurements. In a second time, a one dimensional model based on thermal quadruples and Laplace transforms was developped under Matlab environment. Also, we developped a three dimensional model based on finite volumes using Fluent computational code. Finally, a method of identification of physical parameters is implemented by performing least square minimization based on Levenberg-Marquardt method. The experimental measurements are compared to theoretical results and by minimization we obtain thermal conductivity and diffusivity as well as thickness of the two layers.

  16. Analytical Solution for Interference Fit for Multi-Layer Thick-Walled Cylinders and the Application in Crankshaft Bearing Design

    Directory of Open Access Journals (Sweden)

    Jun Qiu

    2016-06-01

    Full Text Available Interference fit is an important contact mode used for torque transmission existing widely in engineering design. To prevent trackslip, a certain magnitude of interference has to be ensured; meanwhile, the interference needs to be controlled to avoid failure of the mechanical components caused by high assembly stress. The finite element method (FEM can be used to analyze the stress, while the computational cost of FEM involving nonlinear contact algorithm is relatively high, and likely to come across low precision and convergence problems. Therefore, a rapid and accurate analytical method for estimation is of vital need, especially for the initial design stage when the parameters vary in a large range. In this study, an analytical method to calculate the contact pressure and stress between multi-layer thick-walled cylinders (MLTWC with multi-contact pairs and temperature-raising effect is proposed, and evaluated by FEM. The analytical solution of the interference for tri-layer thick-walled cylinders is applied to the design of engine crankshaft bearing. The results indicate that the analytical method presented in this study can reduce complexity of MLTWC problems and improve the computational efficiency. It is well suited to be used for the calculation model of parameter optimization in early design.

  17. DESIGN SOLUTIONS FOR THERMAL INSULATION OF EXTERIOR WALLS OF CAST-IN-PLACE CONCRETE HIGH-RISE RESIDENTIAL BUILDINGS IN CENTRAL REGIONS OF СHINA

    Directory of Open Access Journals (Sweden)

    Bantserova Ol'ga Leonidovna

    2012-12-01

    Full Text Available A significant portion of the overall heat loss is due to the heat loss through the building envelope. According to the opinions of experts, the surface area of exterior walls has the insulation of about 65 % of the total envelope of apartment buildings; therefore, thermal protection of external walls of buildings is a key issue in ensuring the thermal performance of envelopes of apartment buildings. The author has developed design solutions that assure the thermal protection of exterior walls and that are aimed at identifying the optimal solution in terms of the location of insulation materials, their thermal performance and insulation of exterior walls of apartment buildings in central regions of China. The author presents a comparative analysis of the main methodologies of thermal insulation designated for the exterior walls of multi-storey residential buildings: internal and external insulation, as well as the insulation in-between the wall layers. The analyses of wall designs are based on the insulation performance, thermal insulation performance, methods of mounting different systems of insulation, and cost of work. As a result, practical recommendations originate from the statement that the most optimal designs of exterior walls of monolithic high-rise apartment buildings of central regions of China are those that have insulation on the outside of the building. They include layers of insulation made of extruded polystyrene, which is currently planned for use in the construction of high-rise monolithic residential buildings in central China.

  18. Heat transfer through a well insulated external wooden frame wall. An investigation of the effects of normal defects in the insulation resulting from incident wind and air flow through the wall

    Energy Technology Data Exchange (ETDEWEB)

    Roots, P.

    1997-05-01

    The heat requirement of a building can turn out to be greater than was calculated at the design stage. The reason for this may be that heat transport through the building envelope is greater than expected. This in turn can be due to the structure not fulfilling the design requirements in respect to windtightness and airtightness. In addition, there may be defects in the quality of the workmanship of the insulation that significantly reduce the thermal resistance of the external wall. The objective of this investigation has been to ascertain how normal variations in the insulation can affect heat transport through a well-insulated wooden frame external wall under the influences of incident wind or wind flow through the wall. These `normal variations` have been taken to be the presence of electrical conduits, breaks in the insulation, airgaps and nogging pieces, either singly or in combination. For incident wind, measurements in a hotbox and theoretical simulations have shown that the presence of electrical conduits, breaks in the insulation, airgaps or nogging pieces in a well-insulated wooden frame external wall, whether singly or in combination, have negligible effect on thermal transport when subjected to incidnet wind. Heat transport is affected, however, by the presence of a break in the insulation: the combination of electrical conduits, airgaps, a nogging piece and a 16 mm gap in the insulation increased the U-value of the wall by 0.028 W/(m{sup 2.}K) at the most. Measuring the effects of a flow of air through the insulation involved simulating a break in the air seal. A pressure difference of between 10 Pa and 20 Pa was established, causing air to flow from the cold side to the warm side. Measurements and calculations have shown that normal variations in the insulation have a negligible effect on the transmission losses on the cold side, due to the heat exchange effect of the insulation, which raises the temperature of the air flowing through it. This has

  19. The Effects of Roof and Wall Insulation on the Energy Costs of Low Income Housing in Mexico

    Directory of Open Access Journals (Sweden)

    Jorge Lucero-Álvarez

    2016-06-01

    Full Text Available Environmental conditions, such as air temperature and solar radiation, have a complex relationship with the energy requirements for heating and cooling of residential buildings. In this work, a comparative analysis of the insulation methods most commonly applied to low income single-family houses in Mexico is presented, in order to find the most energy-efficient combinations of methods for the various climates in this country. A common kind of building, small houses built with hollow cinder block walls and concrete slab roofs, was analyzed considering three insulation scenarios: walls only, roof only and both. We used dynamic simulation to evaluate energy consumption under the climate conditions found in several Mexican cities. From the energy consumption data and the cost of electricity in Mexico, we calculated net annual energy costs, including both annual energy savings and the annualized cost of the initial investment in better insulation. Results of this analysis show that insulating both roof and walls is most effective in cities with cold winters; insulating just the roof is best for temperate climates; and insulating walls (combined with high-albedo roofs is most effective for cities with year-long warm weather.

  20. Field study of moisture damage in walls insulated without a vapor barrier. Final report for the Oregon Department of Energy

    Energy Technology Data Exchange (ETDEWEB)

    Tsongas, G.A.

    1980-05-01

    Considerable uncertainty has existed over whether or not wall insulation installed without a vapor barrier causes an increased risk of moisture damage (wood decay) within walls. This report describes the results of one of the first major studies in the country aimed at finding out if such a moisture problem really exists. The exterior walls of a total of 96 homes in Portland, Oregon were opened, of which 70 had retrofitted insulation and 26 were uninsulated and were a control group. The types of insulation included urea-formaldehyde foam (44), mineral wool (16), and cellulose (10). In each opened wall cavity the moisture content of wood was measured and insulation and wood samples were taken for laboratory analysis of moisture content and for the determination of the presence of absence of decay fungi. Foam shrinkage was also measured. To evaluate the possible influence of the relative air tightness of the homes, fan depressurization tests were run using a door blower unit. The field and laboratory test results indicating the lack of a moisture damage problem in existing homes with wood siding in climates similar to that of western Oregon are described along with results of a statistical analysis of the data. Related problems of interest to homeowners and insulation installers are noted. The standard operating procedures used throughout the study are discussed, including the home selection process, quantitative and qualitative techniques used to identify wall locations with the highest moisture content, wall opening and data/sample collection methodology, laboratory analysis of samples, data processing and analysis, and applicability of the results. Recommendations for furutre tests are made. Finally, the potential and desirability for future retrofitting of wall insulation is explored.

  1. Validation of a pulsed eddy current system for measuring wall thinning through insulation

    Science.gov (United States)

    Brett, Colin R.; de Raad, Jan A.

    1996-11-01

    There have been several failures in power plant feedwater piping systems due to wall thinning caused by flow- accelerated corrosion of the inner surface. Detection of wastage in susceptible pipes is costly as traditional NDE methods such as ultrasonic testing entail removal and reinstallation of insulation over many meters of pipework. Radiography is one solution to this problem, but it is slow to apply and requires careful attention to safety. The RTD Incotest system uses pulsed eddy current technology to measure pipewall thickness through insulation and external cladding. The technology has been licensed from Arco, Inc., who originally developed the technique for large diameter pipelines and storage tanks where the area interrogated was made deliberately large. This paper describes an optimized Incotest systems which can detect and measure internal or external wall wastage which is more localized and typical of flow-accelerated corrosion. Improvements have also been made to the inspection and data acquisition in order to increase the inspection rate and overall productivity. Ultimately the performance of the optimized Incotest system has been verified on samples which contain artificial and real corrosion.

  2. Thermo Creep Transition in Non-homogeneous Thick-walled Rotating Cylinders

    Directory of Open Access Journals (Sweden)

    Sanjeev Sharma

    2009-01-01

    Full Text Available Creep stresses have been derived using transition theory. The results for the combined effects of angular speed and temperature are calculated and depicted graphically. It has been observed that a cylinder made of less compressible material at the internal surface and highly compressible at the outer surface is on the safer side of the design for different values of N, W2 and temperature as compared to highly compressible material at the internal surface and less compressible at the outer surface.Defence Science Journal, 2009, 59(1, pp.30-36, DOI:http://dx.doi.org/10.14429/dsj.59.1481

  3. A numerical study of multiple adiabatic shear bands evolution in a 304LSS thick-walled cylinder

    Science.gov (United States)

    Liu, Mingtao; Hu, Haibo; Fan, Cheng; Tang, Tiegang

    2017-01-01

    The self-organization of multiple shear bands in a 304L stainless steel(304LSS) thick-walled cylinder (TWC) was numerically studied. The microstructures of material lead to the non-uniform distribution of the local yield stress, which play a key role in the formation of spontaneous shear localization. We introduced a probability factor satisfied the Gaussian distribution into the macroscopic constitutive relationship to describe the non-uniformity of local yield stress. Using the probability factor, the initiation and propagation of multiple shear bands in TWC were numerically replicated in our 2D FEM simulation. Experimental results in the literature indicated that the machined surface at the internal boundary of a 304L stainless steel cylinder provides a work-hardened layer (about 20˜30μm) which has significantly different microstructures from the base material. The work-hardened layer leads to the phenomenon that most shear bands propagate along a given direction, clockwise or counterclockwise. In our simulation, periodical single direction spiral perturbations were applied to describe the grain orientation in the work-hardened layer, and the single direction spiral pattern of shear bands was successfully replicated.

  4. Visual documentation process of historic building refurbishment "Improving energy efficiency by insulating wall cavity"

    Science.gov (United States)

    Bennadji, A.

    2013-07-01

    The North East of Scotland's construction method is similar to most popular building typologies in the UK. This typology can vary in term of external material (Granite, brick or stone) but with a secondary, usually timber sub frame with a lining on its interior. Insulation was seldom a consideration when such buildings were completed. Statistics shows that 80% of existing buildings in the UK will need to be upgraded. The lack of knowledge in dealing with old building fabric's manipulation has a negative impact on buildings' integrity. The documentation of such process seems to be an important step that buildings' actors should undertake to communicate a practical knowledge that is still at incubation stage. We wanted for this documentation to be visual, as descriptions might mislead none specialised and specialised in the field due to the innovative approach our method was conducted with. For the Scottish context this research/experiment will concentrate on existing granite wall buildings with plastered lath internal wall. It is unfortunate to see the commonly beautiful interiors of Scottish buildings disappearing, when the internal linings are removed. Skips are filled with old Plaster and Lath and new linings have to be supplied and fitted. Excessive waste is created in this change. This paper is based on a historic building energy improvement case study financed by the European commission and the Scottish Government. The pilot study consists of insulating an 18th century house using an innovative product and method. The project was a response to a call by the CIC start (Construction Innovation Club), aiming to establish a link between SMEs and the Universities. The project saw the day in collaboration with Icynene Canada, KDL Kishorn (see full list in the acknowledgment). This paper describes the process through which the team went through to improve the building envelope without damaging the buildings original features (Loveday et all). The energy efficiency

  5. The Effectiveness of Thermal Insulation in Lightweight Steel-Framed Walls with Respect to Its Position

    Directory of Open Access Journals (Sweden)

    Eduardo Roque

    2017-02-01

    Full Text Available Lightweight steel-framed (LSF construction, given its advantages, has the potential to reach high standards in energy and environmental performance of buildings, such as nearly zero-energy buildings (nZEB. When compared with traditional construction, LSF system offers distinct benefits in such fields as sustainability, cost-effectiveness, constructive process, and safety at work. Despite the benefits of this constructive system, the effect of thermal bridges in LSF elements, caused by the high thermal conductivity of the steel structure, can be a disadvantage. The excessive heat losses or gains through these thermal bridges are more relevant in buildings’ exterior envelope, such as facade walls. These building components’ thermal performance is crucial in the buildings’ overall energetic behaviour, with a direct impact on energy consumption and resulting monetary costs during their operational stage. In this work the influence of the thermal insulation position on its effectiveness is evaluated in LSF facade walls. For this purpose, several LSF wall types are assessed, namely cold, warm, and hybrid construction. The influence of thermal bridges instigated by the steel studs in the LSF walls’ overall thermal performance is evaluated as well. The computations are performed using specialized finite element software (THERM.

  6. The Characteristic of Thermoelastic Waves in Transversely Isotropic Finite Cylinders

    Directory of Open Access Journals (Sweden)

    Bai Hao

    2017-01-01

    Full Text Available A theoretical as well as a numerical investigation of the propagation of thermoelastic waves and vibration of transversely isotropic cylinders of finite length is discussed. Lord-Shulman theory is adopted here to model the thermoelastic deformation of cylinders. A semi analytical finite element (SAFE method is employed to study dispersion of thermoelastic waves and natural frequencies of vibration of finite cylinders with traction free curved surfaces having both ends insulated and constrained by frictionless rigid walls. Numerical results obtained by the SAFE method for the frequencies of vibration of a sapphire rod are found to be in excellent agreement with published results. Natural frequencies of vibration for first three axisymmetric and asymmetric modes are presented graphically for a silicon nitride thermoelastic cylinder. Also, numerical results showing dispersion of both propagating and evanescent circumferential waves in infinite and finite cylinders are presented also.

  7. Mesoscopic Metal-Insulator Transition at Ferroelastic Domain Walls in VO2

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Keith M [ORNL; Kalinin, Sergei V [ORNL; Kolmakov, Andrei [ORNL; Luk' yanchuk, Prof. Igor A. [University of Picardie Jules Verne, Amiens, France; Meunier, Vincent [ORNL; Proksch, Roger [Asylum Research, Santa Barbara, CA; Shelton Jr, William Allison [ORNL; Strelcov, Evgheni [Southern Illinois University; Tselev, Alexander [ORNL

    2010-01-01

    The novel phenomena induced by symmetry breaking at homointerfaces between ferroic variants in ferroelectric and ferroelastic materials have attracted recently much attention. Using variable temperature scanning microwave microscopy, we demonstrate the mesoscopic strain-induced metal-insulator phase transitions in the vicinity of ferroelastic domain walls in the semiconductive VO2 that nucleated at temperatures as much as 10-12 C below bulk transition, resulting in the formation of conductive channels in the material. Density functional theory is used to rationalize the process low activation energy. This behavior, linked to the strain inhomogeneity inherent in ferroelastic materials, can strongly affect interpretation of phase-transition studies in VO2 and similar materials with symmetry-lowering transitions, and can also be used to enable new generations of electronic devices though strain engineering of conductive and semiconductive regions.

  8. Effects of domain walls in quantum anomalous Hall insulator/superconductor heterostructures

    Science.gov (United States)

    Chen, Chui-Zhen; He, James Jun; Xu, Dong-Hui; Law, K. T.

    2017-07-01

    In a recent experiment, half-quantized longitudinal conductance plateaus (HQCPs) of height e/22 h have been observed in quantum anomalous Hall (QAH) insulator/superconductor heterostructure transport measurements. However, there are debates about whether these HQCPs are caused by Majorana edge modes or other trivial reasons. It was predicted that HQCPs can only appear when the Hall conductance σx y is quantized. Surprisingly, HQCPs appear when the Hall conductance σx y is only 80% of the quantized value at which extra conducting channels in the bulk should ruin the HQCPs. In this Rapid Communication, we explain how domain walls can cause σx y to deviate from its quantized value and at the same time maintain the quantization of HQCPs. Importantly, our study also explains a long standing puzzle of why ρx x can be finite when ρx y is quantized in QAH systems.

  9. LES and Hybrid LES/RANS Study of Flow and Heat Transfer around a Wall-Bounded Short Cylinder

    Science.gov (United States)

    Borello, D.; Delibra, G.; Hanjalić, K.; Rispoli, F.

    The flow in plate-fin-and-tube heat exchangers is featured by interesting dynamics of vortical structures, which, due to close proximity of bounding walls that suppress instabilities, differs significantly from the better-known patterns around long cylinders. Typically, several distinct vortex systems can be identified both in front and behind the pin. Their signature on the pin and end-walls reflects directly in the local heat transfer. The Reynolds numbers is usually moderate and the incoming flow is non-turbulent, transiting to turbulence on or just behind the first or few subsequent pin/tube rows. Upstream from the first pin a sequence of several horseshoe vortices attached to the boundingwall is created, while the unsteady wake contains also multiple vortical systems which control the entrainment of fresh fluid and its mixing with the hot fluid that was in contact with the heated surfaces [1]. The conventional CFD using standard turbulence models, as practiced by heat exchangers industries, falls short in capturing the subtle details of the complex vortex systems. A fine-grid LES can provide accurate solutions, but for more complex configurations and higher Re numbers a hybrid RANS/LES using a coarser grid seems a more rational option, provided it can capture all important flow and vortical features.

  10. Analytical solution for spatially axisymmetric problem of thick-walled cylinder subjected to different linearly varying pressures along the axis and uniform pressures at two ends

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    To our best knowledge,in the open literature,there is no analytical solution of thick-walled cylinder subjected to uniform pressures at two ends and different inner-and outer-surface pressures that are constant circumferentially but vary linearly at different rates along the axis.We now present such a solution.After repeated trials,we have finally succeeded in finding a necessary new displacement function.Based on A.E.H.Love method,the stress,displacement and volume strain formulas are derived by using the new displacement function.The present results include the Lamé’s formulas as special cases.Furthermore,the results obtained here can be applied to not only the thick-walled cylinders subjected to uniform pressures on the inner and outer surface of the thick-walled cylinder,respectively,but also the cylinders subjected to uniform pressures at two ends and dif- ferent inner-and outer-surface pressures that are constant circumferentially but vary linearly at different rates along the axis,respectively.Finally we give a numerical example to compare our exact method with the approximate method.

  11. Stress-induced self-rolled metal/insulator bifilm microtube with micromesh walls

    Science.gov (United States)

    Lee, Kook-Nyung; Seo, Yeong-Tai; Lee, Min-Ho; Jung, Suk-Won; Kim, Yong-Kweon; Kim, Jung-Mu; Kyeong Seong, Woo

    2013-01-01

    A metal/insulator microtube with micromesh walls was constructed using stress-assisted self-rolling technology. The mesh-sidewall Pt/Ti/SiO2 microtube was self-formed by a tensile-stressed metal Pt/Ti film deposited onto a pre-patterned SiO2 micromesh layer. The microtube measured about 25 µm in diameter and was longer than 7 mm. The sidewall of the microtube was a square mesh, 5-20 µm long, and was electrically connected to electrical pads for electrical conductance measurement. The electrical resistance of the rolled-up microtube was measured to be 250-350 Ω when the microtube resistor's length was around 540 µm. The real-time measurement of the conductance change of the microtube with a Pt resistor could monitor the temperature change generated by heat injection. The microtube with micromesh walls is expected to be an interesting structure that has promising potential for use in electronics, chemical and biological applications.

  12. Constructal optimization of a vertical insulating wall based on a complex objective combining heat flow and strength

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    For a vertical insulating wall,a product function of heat flow and strength with power weight is introduced as the complex optimization objective to compromise between insulating performance and mechanical performance.Under the global constraints of fixed external dimensions and safety requirements,the constructal optimization of the wall is carried out by taking the complex function maximization as the objective.It is shown that the maximum of the complex-objective function and its corresponding optimal internal structure design under a certain environmental condition can be obtained by allowing the internal structure of the wall to vary(evolve)freely.The validity,effectivity and applicability of the complex function are proved by the results and the power weight parameter in the range from 0.4 to 4 can compromise between the requirements of insulating and strength simultaneously and preferably.The constructal optimization with coequal attention to heat flow and strength and the corresponding results are discussed in detail.The optimal structure design and the corresponding performance analyses under various environmental conditions of application are presented.When the change of environment is greater and the total Rayleigh number is bigger,the insulating wall with large number of cavities should be employed.When the total Rayleigh number is small,the better performance can be obtained by reasonably employing the insulating wall with small number of cavities.The complex function has better selfadaptability,and the results in the recent literature are special cases of this paper.

  13. Building America Case Study: Construction Guidelines for High R-Value Walls without Exterior Rigid Insulation, Cold Climate Region

    Energy Technology Data Exchange (ETDEWEB)

    2017-01-01

    High-R wall assemblies (R-40 and above) are gaining popularity in the market due to programs like the DOE's Zero Energy Ready Home program, Passive House (PH), Net Zero Energy Home (NZEH) challenges in several states, and highly incentivized retrofit programs. In response to this demand, several builders have successfully used 'double wall' systems to more practically achieve higher R-values in thicker, framed walls. To builders of conventional stick-framed homes, often one of the most appealing features of double wall systems is that there are very few new exterior details. Exterior sheathing, structural bracing, house wrap or building paper, window and door flashing, and siding attachment are usually identical to good details in conventional framed wall systems. The information presented in this guide is intended to reduce the risk of failure in these types of assemblies, increase durability, and result in a reduction of material brought to landfills due to failures and resulting decay. While this document focuses on double wall framing techniques, the majority of the information on how to properly construct and finish high R-value assemblies is applicable to all wall assemblies that do not have foam insulation installed on the exterior of the structural sheathing. The techniques presented have been shown through field studies to reduce the likelihood of mold growth and moisture related damage and are intended for builders, framing contractors, architects, and consultants involved in designing and building super insulated homes.

  14. Building America Case Study: Construction Guidelines for High R-Value Walls without Exterior Rigid Insulation, Cold Climate Region

    Energy Technology Data Exchange (ETDEWEB)

    L. Arena

    2017-01-01

    High-R wall assemblies (R-40 and above) are gaining popularity in the market due to programs like the DOE's Zero Energy Ready Home program, Passive House (PH), Net Zero Energy Home (NZEH) challenges in several states, and highly incentivized retrofit programs. In response to this demand, several builders have successfully used 'double wall' systems to more practically achieve higher R-values in thicker, framed walls. To builders of conventional stick-framed homes, often one of the most appealing features of double wall systems is that there are very few new exterior details. Exterior sheathing, structural bracing, house wrap or building paper, window and door flashing, and siding attachment are usually identical to good details in conventional framed wall systems. The information presented in this guide is intended to reduce the risk of failure in these types of assemblies, increase durability, and result in a reduction of material brought to landfills due to failures and resulting decay. While this document focuses on double wall framing techniques, the majority of the information on how to properly construct and finish high R-value assemblies is applicable to all wall assemblies that do not have foam insulation installed on the exterior of the structural sheathing. The techniques presented have been shown through field studies to reduce the likelihood of mold growth and moisture related damage and are intended for builders, framing contractors, architects, and consultants involved in designing and building super insulated homes.

  15. The Spalling of Geopolymer High Strength Concrete Wall Panels and Cylinders Under Hydrocarbon Fire

    Directory of Open Access Journals (Sweden)

    Mohd Ali Ahmad Zurisman

    2016-01-01

    Full Text Available Concrete structures were designed to withstand various types of environment conditions from mild to very severe conditions. Fire represents one of the most severe environmental conditions to which concrete structures may be subjected especially in close conduct structure like tunnel. This paper focuses on the spalling of geopolymer high strength concrete exposed to hydrocarbon fire for minimum 2 hours. From the fire test, geopolymer concrete can be classified as a good fire resistance construction materials based on spalling performance of high strength concrete when exposed to hydrocarbon fire. A maximum of 1% (excluding water moisture loss of spalling recorded for high strength geopolymer concrete wall panel. No explosive spallings were observed for high strength geopolymer concrete.

  16. Building America Case Study: Retrofit Measure for Embedded Wood Members in Insulated Mass Masonry Walls, Lawrence, Massachusetts

    Energy Technology Data Exchange (ETDEWEB)

    2015-10-01

    ?There are many existing buildings with load-bearing mass masonry walls, whose energy performance could be improved with the retrofit of insulation. However, adding insulation to the interior side of walls of such masonry buildings in cold (and wet) climates may cause performance and durability problems. Some concerns, such as condensation and freeze-thaw have known solutions. But wood members embedded in the masonry structure will be colder (and potentially wetter) after an interior insulation retrofit. Moisture content and relative humidity were monitored at joist ends in historic mass brick masonry walls retrofitted with interior insulation in a cold climate (Zone 5A); data were collected from 2012-2015. Eleven joist ends were monitored in all four orientations. One limitation of these results is that the renovation is still ongoing, with limited wintertime construction heating and no permanent occupancy to date. Measurements show that many joists ends remain at high moisture contents, especially at north- and east-facing orientations, with constant 100 percent RH conditions at the worst cases. These high moisture levels are not conducive for wood durability, but no evidence for actual structural damage has been observed. Insulated vs. non-insulated joist pockets do not show large differences. South facing joists have safe (10-15 percent) moisture contents. Given the uncertainty pointed out by research, definitive guidance on the vulnerability of embedded wood members is difficult to formulate. In high-risk situations, or when a very conservative approach is warranted, the embedded wood member condition can be eliminated entirely, supporting the joist ends outside of the masonry pocket.

  17. Catastrophic vs gradual collapse of thin-walled nanocrystalline Ni hollow cylinders as building blocks of microlattice structures.

    Science.gov (United States)

    Lian, Jie; Jang, Dongchan; Valdevit, Lorenzo; Schaedler, Tobias A; Jacobsen, Alan J; B Carter, William; Greer, Julia R

    2011-10-12

    Lightweight yet stiff and strong lattice structures are attractive for various engineering applications, such as cores of sandwich shells and components designed for impact mitigation. Recent breakthroughs in manufacturing enable efficient fabrication of hierarchically architected microlattices, with dimensional control spanning seven orders of magnitude in length scale. These materials have the potential to exploit desirable nanoscale-size effects in a macroscopic structure, as long as their mechanical behavior at each appropriate scale - nano, micro, and macro levels - is properly understood. In this letter, we report the nanomechanical response of individual microlattice members. We show that hollow nanocrystalline Ni cylinders differing only in wall thicknesses, 500 and 150 nm, exhibit strikingly different collapse modes: the 500 nm sample collapses in a brittle manner, via a single strain burst, while the 150 nm sample shows a gradual collapse, via a series of small and discrete strain bursts. Further, compressive strength in 150 nm sample is 99.2% lower than predicted by shell buckling theory, likely due to localized buckling and fracture events observed during in situ compression experiments. We attribute this difference to the size-induced transition in deformation behavior, unique to nanoscale, and discuss it in the framework of "size effects" in crystalline strength.

  18. Solar wall heating and daylight use with transparent thermal insulation - the solar environmental wall; Solare Wandheizung und Tageslichtnutzung mit Transparenter Waermedaemmung - die Solare Umweltwand

    Energy Technology Data Exchange (ETDEWEB)

    Platzer, W. [Fachverband Transparente Waermedaemmung e.V., Gundelfingen (Germany)

    2005-07-01

    Construction with the sun means to open building walls for the sun. The building is supposed to benefit directly from daylight and solar heat. Special materials were developed for this purpose, which combine solar transmission and light transmission. They enable the transparent thermal insulation of buildings, abbreviated TWD. Their integration into the facade and the roof offer an intelligent and uncomplicated technology for the use of solar energy, the ''solar environmental wall''. TWD-materials can be used as filling material in various building components and they already constitute a weather-resistant wall. They are thermally-insulating structures or materials, which keep out the heat but allow the transmission of solar radiation and light. TWD-materials maintain their excellent insulating properties almost unchanged even in case of very cold outer temperatures or inclined construction in the roof area. In these cases the convection of components that are only filled with air or gas, can lead to considerable decreases of the U-value (according to DIN EN 673 up to 45%). Good TWD-materials are resistant against humidity, which enables to use them in non-hermetic systems, such as e.g. U-profile glas, too. (orig.)

  19. Performance of Screen Grid Insulating Concrete Form Walls under Combined In-Plane Vertical and Lateral Loads

    KAUST Repository

    Abdel Mooty, Mohamed

    2010-12-01

    Insulating Concrete Forms (ICF) walls generally comprise two layers of Expanded Polystyrene (EPS), steel reinforcement is placed in the center between the two layers and concrete is poured to fill the gap between those two layers. ICF\\'s have many advantages over traditional methods of wall construction such as reduced construction time, noise reduction, strength enhancement, energy efficiency, and compatibility with any inside or outside surface finish. The focus of this study is the Screen Grid ICF wall system consisting of a number of beams and columns forming a concrete mesh. The performance of ICF wall systems under lateral loads simulating seismic effect is experimentally evaluated in this paper. This work addresses the effect of the different design parameters on the wall behavior under seismic simulated loads. This includes different steel reinforcement ratio, various reinforcement distribution, wall aspect ratios, different openings sizes for windows and doors, as well as different spacing of the grid elements of the screen grid wall. Ten full scale wall specimens were tested where the effects of the various parameters on wall behavior in terms of lateral load capacity, lateral displacement, and modes of failure are presented. The test results are stored to be used for further analysis and calibration of numerical models developed for this study. © (2011) Trans Tech Publications.

  20. Building materials and systems with vacuum insulation panels for external walls; Bauelemente und Systeme mit VIP fuer Aussenwandkonstruktionen - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Binz, A.; Steinke, G.

    2007-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) takes a look at materials and systems using vacuum insulation panels (VIP) for the construction of external walls. The aim of this research project was the development, practical use and market introduction of VIP systems that take account of the special properties of VIP. Along with partners in industry, applications involving external and internal insulation were examined. The need for protecting the vacuum panels against mechanical damage is stressed. The specific needs for the protection of external and internal applications are discussed. The dynamic developments in this relatively new area are commented on. Various mounting systems are examined and commented on. The thermal properties of such insulation systems and applications are noted and commented on.

  1. Determination of Optimum Thermal Insulation Thicknesses for External Walls Considering the Heating, Cooling and Annual Energy Requirement

    Directory of Open Access Journals (Sweden)

    Ömer KAYNAKLI

    2016-06-01

    Full Text Available In this study, optimization of thermal insulation thickness applied to the external walls of buildings has been carried out comparatively based on the seasonal (space-heating and cooling and the annual energy requirements considering solar radiation effect. This study has been performed for four degree-day regions of Turkey, namely, Iskenderun (in the first region, Istanbul (in the second region, Ankara (in the third region and Ardahan (in the fourth region. By determining the sol-air temperatures for each region and maximizing the present worth value of seasonal and annual energy savings, the optimum thermal insulation thicknesses have been calculated. The effects of solar radiation on heating-cooling energy requirements, the variation of optimum insulation thicknesses and payback periods with respect to degree-day regions, the differences between the analyses based on seasonal and annual have been presented in tabular and graphical form.

  2. Polarization domain wall pulses in a microfiber-based topological insulator fiber laser

    Science.gov (United States)

    Liu, Jingmin; Li, Xingliang; Zhang, Shumin; Zhang, Han; Yan, Peiguang; Han, Mengmeng; Pang, Zhaoguang; Yang, Zhenjun

    2016-07-01

    Topological insulators (TIs), are novel two-dimension materials, which can act as effective saturable absorbers (SAs) in a fiber laser. Moreover, based on the evanescent wave interaction, deposition of the TI on microfiber would create an effective SA, which has combined advantages from the strong nonlinear optical response in TI material together with the sufficiently-long-range interaction length in fiber taper. By using this type of TI SA, various scalar solitons have been obtained in fiber lasers. However, a single mode fiber always exhibits birefringence, and hence can support two orthogonal degenerate modes. Here we investigate experimentally the vector characters of a TI SA fiber laser. Using the saturated absorption and the high nonlinearity of the TI SA, a rich variety of dynamic states, including polarization-locked dark pulses and their harmonic mode locked counterparts, polarization-locked noise-like pulses and their harmonic mode locked counterparts, incoherently coupled polarization domain wall pulses, including bright square pulses, bright-dark pulse pairs, dark pulses and bright square pulse-dark pulse pairs are all observed with different pump powers and polarization states.

  3. Direct observation of nanoscale Peltier and Joule effects at metal-insulator domain walls in vanadium dioxide nanobeams.

    Science.gov (United States)

    Favaloro, Tela; Suh, Joonki; Vermeersch, Bjorn; Liu, Kai; Gu, Yijia; Chen, Long-Qing; Wang, Kevin X; Wu, Junqiao; Shakouri, Ali

    2014-05-14

    The metal to insulator transition (MIT) of strongly correlated materials is subject to strong lattice coupling, which brings about the unique one-dimensional alignment of metal-insulator (M-I) domains along nanowires or nanobeams. Many studies have investigated the effects of stress on the MIT and hence the phase boundary, but few have directly examined the temperature profile across the metal-insulating interface. Here, we use thermoreflectance microscopy to create two-dimensional temperature maps of single-crystalline VO2 nanobeams under external bias in the phase coexisting regime. We directly observe highly localized alternating Peltier heating and cooling as well as Joule heating concentrated at the M-I domain boundaries, indicating the significance of the domain walls and band offsets. Utilizing the thermoreflectance technique, we are able to elucidate strain accumulation along the nanobeam and distinguish between two insulating phases of VO2 through detection of the opposite polarity of their respective thermoreflectance coefficients. Microelasticity theory was employed to predict favorable domain wall configurations, confirming the monoclinic phase identification.

  4. NON-LINEAR TRANSIENT HEAT CONDUCTION ANALYSIS OF INSULATION WALL OF TANK FOR TRANSPORTATION OF LIQUID ALUMINUM

    OpenAIRE

    Miroslav M Živković; Aleksandar V Nikolić; Radovan B Slavković; Fatima T Živić

    2010-01-01

    This paper deals with transient nonlinear heat conduction through the insulation wall of the tank for transportation of liquid aluminum. Tanks designed for this purpose must satisfy certain requirements regarding temperature of loading and unloading, during transport. Basic theoretical equations are presented, which describe the problem of heat conduction finite element (FE) analysis, starting from the differential equation of energy balance, taking into account the initial and boundary condi...

  5. The roles of thermal insulation and heat storage in the energy performance of the wall materials: a simulation study.

    Science.gov (United States)

    Long, Linshuang; Ye, Hong

    2016-04-07

    A high-performance envelope is the prerequisite and foundation to a zero energy building. The thermal conductivity and volumetric heat capacity of a wall are two thermophysical properties that strongly influence the energy performance. Although many case studies have been performed, the results failed to give a big picture of the roles of these properties in the energy performance of an active building. In this work, a traversal study on the energy performance of a standard room with all potential wall materials was performed for the first time. It was revealed that both heat storage materials and insulation materials are suitable for external walls. However, the importances of those materials are distinct in different situations: the heat storage plays a primary role when the thermal conductivity of the material is relatively high, but the effect of the thermal insulation is dominant when the conductivity is relatively low. Regarding internal walls, they are less significant to the energy performance than the external ones, and they need exclusively the heat storage materials with a high thermal conductivity. These requirements for materials are consistent under various climate conditions. This study may provide a roadmap for the material scientists interested in developing high-performance wall materials.

  6. Effect of Thermal Bridges in Insulated Walls on Air-Conditioning Loads Using Whole Building Energy Analysis

    Directory of Open Access Journals (Sweden)

    Mohamed F. Zedan

    2016-06-01

    Full Text Available Thermal bridges in building walls are usually caused by mortar joints between insulated building blocks and by the presence of concrete columns and beams within the building envelope. These bridges create an easy path for heat transmission and therefore increase air-conditioning loads. In this study, the effects of mortar joints only on cooling and heating loads in a typical two-story villa in Riyadh are investigated using whole building energy analysis. All loads found in the villa, which broadly include ventilation, transmission, solar and internal loads, are considered with schedules based on local lifestyles. The thermal bridging effect of mortar joints is simulated by reducing wall thermal resistance by a percentage that depends on the bridges to wall area ratio (TB area ratio or Amj/Atot and the nominal thermal insulation thickness (Lins. These percentage reductions are obtained from a correlation developed by using a rigorous 2D dynamic model of heat transmission through walls with mortar joints. The reduction in thermal resistance is achieved through minor reductions in insulation thickness, thereby keeping the thermal mass of the wall essentially unchanged. Results indicate that yearly and monthly cooling loads increase almost linearly with the thermal bridge to wall area ratio. The increase in the villa’s yearly loads varies from about 3% for Amj/Atot = 0.02 to about 11% for Amj/Atot = 0.08. The monthly increase is not uniform over the year and reaches a maximum in August, where it ranges from 5% for Amj/Atot = 0.02 to 15% for Amj/Atot = 0.08. In winter, results show that yearly heating loads are generally very small compared to cooling loads and that heating is only needed in December, January and February, starting from late night to late morning. Monthly heating loads increase with the thermal bridge area ratio; however, the variation is not as linear as observed in cooling loads. The present results highlight the importance of

  7. The influence of thermal insulation position in building exterior walls on indoor thermal comfort and energy consumption of residential buildings in Chongqing

    Science.gov (United States)

    Wang, D.; Yu, W.; Zhao, X.; Dai, W.; Ruan, Y.

    2016-08-01

    This paper focused on the influence of using position of thermal insulation materials in exterior walls on the indoor thermal comfort and building energy consumption of residential building in Chongqing. In this study, four (4) typical residential building models in Chongqing were established, which have different usage of thermal insulation layer position in exterior walls. Indoor thermal comfort hours, cooling and heating energy consumption of each model were obtained by using a simulation tool, Energyplus. Based on the simulation data, the influence of thermal insulation position on indoor thermal comfort and building energy consumption in each season was analyzed. The results showed that building with internal insulation had the highest indoor thermal comfort hours and least cooling and heating energy consumption in summer and winter. In transitional season, the highest indoor thermal comfort hours are obtained when thermal insulation is located on the exterior side.

  8. Preparation and performance of thermal insulation energy saving coating materials for exterior wall.

    Science.gov (United States)

    Wang, Fei; Liang, Jinsheng; Tang, Qingguo; Chen, Gong; Chen, Yalei

    2014-05-01

    Nano zinc oxide with a high refractive index has good thermal reflection performance, hollow glass microspheres have good thermal reflection and insulation performance, and sepiolite nanofibers with many nanostructural pores have good thermal insulation performance. The dispensability of nano zinc oxide in coating materials was improved by optimizing surface silane coupling agent modification process, leading to the good thermal reflection performance. The thermal insulation performance was improved by hollow glass microspheres and sepiolite nanofibers. On this basis, the thermal insulation coating materials were prepared by exploring the effect of amount, complex mode, and other factors of the above three kinds of functional fillers on the thermal reflection and insulation performance of coating materials. The results showed that the surface modification effect of nano zinc oxide was the best when the silane coupling agent addition was 6%. The reflection and insulation performance of the coatings were the best when the additions of modified nano zinc oxide, hollow glass microspheres, and sepiolite nanofibers were 3%, 4%, and 4%, respectively. Compared with the control coating materials, the thermal insulation effect was improved obviously, which was evaluated by the -13.5 degrees C increase of maximum temperature difference between the upper and the lower surfaces.

  9. Delamination of Composite Cylinders

    Science.gov (United States)

    Davies, Peter; Carlsson, Leif A.

    The delamination resistance of filament wound glass/epoxy cylinders has been characterized for a range of winding angles and fracture mode ratios using beam fracture specimens. The results reveal that the delamination fracture resistance increases with increasing winding angle and mode II (shear) fraction (GΠ/G). It was also found that interlaced fiber bundles in the filament wound cylinder wall acted as effective crack arresters in mode I loading. To examine the sensitivity of delamina-tion damage on the strength of the cylinders, external pressure tests were performed on filament-wound glass/epoxy composite cylinders with artificial defects and impact damage. The results revealed that the cylinder strength was insensitive to the presence of single delaminations but impact damage caused reductions in failure pressure. The insensitivity of the failure pressure to a single delamination is attributed to the absence of buckling of the delaminated sublaminates before the cylinder wall collapsed. The impacted cylinders contained multiple delaminations, which caused local reduction in the compressive load capability and reduction in failure pressure. The response of glass/epoxy cylinders was compared to impacted carbon reinforced cylinders. Carbon/epoxy is more sensitive to damage but retains higher implosion resistance while carbon/PEEK shows the opposite trend.

  10. 汽车用液化天然气钢瓶绝热性能在线检测技术研究%Research on Thermal Insulation Performance of Liquefied Nature Gas Cylinders for Automotive Through Online Inspection Technology

    Institute of Scientific and Technical Information of China (English)

    瞿伟健; 肖超波

    2015-01-01

    为开展汽车用液化天然气钢瓶绝热性能的在线检验,研究了汽车用液化天然气钢瓶初始充满率与静态升压值和静态蒸发率的相互关系。结果表明,其静态蒸发率与静态升压值呈正比,静态蒸发率越大,静态升压值越大。初始充满率在70%~90%内,静态升压值的变化能够较准确、快速、直观地反映钢瓶的绝热性能,可作为评价液化天然气钢瓶绝热性能在线测试的一种方法。%The relationship of the initial filling rate,the static pressure value,the static rate of evaporation are researched,in order to provide the theoretical basis for the online inspection of liquefied nature gas cylinders.The results showed that,static rate of evaporation of liquefied nat-ural gas cylinder and static boost value is proportional to the static rate of evaporation,static e-vaporation rate is greater,the greater the value of static pressure rise.When the initial rate of e-vaporation of liquefied nature gas cylinders is 70% ~90%,static boost can accurately,quickly and intuitively reflect the performance of heat insulation cylinder,can be used as a method to e-valuate the insulation performance of liquefied natural gas cylinder for online testing.

  11. Mineral thermal insulation systems for low-energy buildings: Optimum insulation of external walls; Mineralische Aussenwaermedaemmsysteme fuer Niedrigenergiehaeuser: Der richtige Rahmen

    Energy Technology Data Exchange (ETDEWEB)

    Pfefferkorn, J. [Fixit AG, Weiach (Switzerland)

    1997-05-01

    Low-energy buildings are complex systems. Many different criteria must be observed in their construction, and object-specific details must be viewed in the context of the overall system. Good thermal insulation alone does not make a low-energy building, but also the energy turnover of the external wall construction and its environmental acceptability must be taken into account. HAUSTECH presents the example of a new low-energy building with an efficient solar system in order to indicate the criteria that must be observed in particular for wall constructions of low-energy buildings in the Swiss low mountain regions. (orig.) [Deutsch] Niedrigenergiehaeuser sind komplexe Systeme. Bei der Planung und Realisierung muessen die verschiedensten Anforderungskriterien beruecksichtigt und einzelne objektspezifische Details im Hinblick auf das ganze System hinterfragt werden. Eine gute Waermedaemmung allein macht noch kein Niedrigenergiehaus aus. Die ganzheitliche Betrachtung schliesst auch den Energiehaushalt der Aussenwandkonstruktion und deren Umweltvertraeglichkeit mit ein. `HAUS TECH` zeigt anhand eines kuerzlich fertiggestellten Niedringenergiehauses, in dem auch die Solartechnik wirkungsvoll eingesetzt wird, auf, welche Kriterien bei Wandkonstruktionen fuer solche Bauten im schweizerischen Mittelland besonders zu beachten sind. (orig.)

  12. 混凝土面层绝热外挂墙板%Concrete faceplate thermal insulation external installation wall panel

    Institute of Scientific and Technical Information of China (English)

    罗刚; 黄远洋; 刘吉贵; 李鸿辉; 张阳

    2011-01-01

    介绍一种新型的适合外挂的混凝土夹芯墙板以及该墙板的设计思想和样品的制作方法.该夹芯墙板设置了连接混凝土面层的拉结件,形成了在力学性能上与绝热芯材无关的箱型结构.拉结件采用低导热系数、高抗拉强度的材料制作,从而消除了板内的冷桥.实验表明该墙板具有良好的力学性能、防火性能、水密性能、抗风压性能及抗震性能.通过样板房搭建,初步证实该新型墙板在实际工程中的可操作性,其外挂的安装方式可以彻底消除主体结构梁、柱的冷桥问题,是一种高效绝热、低成本的新型墙板.%In this article,a new type of concrete thermal insulation sandwich external wall panel, as well as its design ideal and way af sample producing are introduced. The sandwich wall panel has pulling parts to connecting the concrete faceplates,forming a box structure with the mechanical properties irrelevant to the thermal insulation core material. The pulling parts are made with materials of low thermal conductivity but high tensile strength,so the cold bridges effect in the panel is eliminated.The experiments results show that this external wall panel has good quality on mechanical properties, fire resiatance,water tightness,wind load resistance performance and seismic performance. The sample room's setup has confirmed the new type wall panel's operability in the actual building project, and the external installatian mode can thoroughly solve the problem of cold bridges effect in the main building structures, such as beams and columns, which proves this is a new type wall panel of high thermal insulation efficient and low cost.

  13. DC Voltage Insulation Characteristics and Influencing Factors for Coaxial Cylinder SF6 Gap%同轴圆柱SF6气体间隙直流绝缘特性及其影响因素

    Institute of Scientific and Technical Information of China (English)

    冀肖彤; 汤浩; 李金忠

    2012-01-01

    Coaxial cylinder is the basic structure in DC SF6 gas-insulated equipment. The basic research platform of DC SF6 gas-insulation characteristics was developed to study the insulation characteristics of different gap length and gas pressure. Based on these test results, the calculation model of breakdown voltage of SF6 in long length coaxial cylinder gap was established. Besides, the effect of surface roughness, metallic conducting particle and electrode surface area were also researched and analyzed. The calculation model which is obtained from similar non-uniformity of field and surface roughness with DC SF6 gas-insulated equipment can be used for insulation optimization.%同轴圆柱是直流SF6气体绝缘设备的基本结构,研制了不同间隙长度和不同气体压力下直流SF6气体绝缘特性基础研究平台,通过试验研究建立了长间隙同轴圆柱SF6间隙直流击穿电压计算模型,对影响间隙直流绝缘特性的表面粗糙度、金属导电微粒、电极表面积大小进行了试验研究和分析.由与直流气体绝缘设备的电场不均匀系数和表面粗糙相似的电极得出的击穿电压计算模型,可为SF6气体间隙绝缘优化提供依据.

  14. 机械自紧厚壁圆管强度的实验研究%Experimental Research on Thick-walled Cylinder Strength with Swage Autofrettage

    Institute of Scientific and Technical Information of China (English)

    袁人枢; 连源

    2012-01-01

    设计了机械自紧实验所用的厚壁圆筒试件,搭建了机械自紧实验装置,对不同径比、不同过盈量的厚壁圆筒进行机械自紧实验,测试自紧后试件的再屈服强度.考虑稳定化处理和机械加工的工艺过程,结合实验结果提出机械自紧厚壁圆管强度计算经验公式,计算得到的强度数值与实验测量值的误差在±10%以内.%The thick-walled cylinder specimen was designed and the swage autofrettage experimental devicefor the thick-walled cylinder which boasting of different diameter ratios and magnitudes of interference was built to test re-yield strength of the specimen; and considering the post-autofrettage thermal treatment and machining and experimental results, the empirical formula for the strength was obtained and the results show that the experimental error between calculated result and experimental result is less then ?10% .

  15. Advanced Insulation for High Performance Cost-Effective Wall, Roof, and Foundation Systems Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Costeux, Stephane [Dow Chemical Company, Midland, MI (United States); Bunker, Shanon [Dow Chemical Company, Midland, MI (United States)

    2013-12-20

    The objective of this project was to explore and potentially develop high performing insulation with increased R/inch and low impact on climate change that would help design highly insulating building envelope systems with more durable performance and lower overall system cost than envelopes with equivalent performance made with materials available today. The proposed technical approach relied on insulation foams with nanoscale pores (about 100 nm in size) in which heat transfer will be decreased. Through the development of new foaming methods, of new polymer formulations and new analytical techniques, and by advancing the understanding of how cells nucleate, expand and stabilize at the nanoscale, Dow successfully invented and developed methods to produce foams with 100 nm cells and 80% porosity by batch foaming at the laboratory scale. Measurements of the gas conductivity on small nanofoam specimen confirmed quantitatively the benefit of nanoscale cells (Knudsen effect) to increase insulation value, which was the key technical hypotheses of the program. In order to bring this technology closer to a viable semi-continuous/continuous process, the project team modified an existing continuous extrusion foaming process as well as designed and built a custom system to produce 6" x 6" foam panels. Dow demonstrated for the first time that nanofoams can be produced in a both processes. However, due to technical delays, foam characteristics achieved so far fall short of the 100 nm target set for optimal insulation foams. In parallel with the technology development, effort was directed to the determination of most promising applications for nanocellular insulation foam. Voice of Customer (VOC) exercise confirmed that demand for high-R value product will rise due to building code increased requirements in the near future, but that acceptance for novel products by building industry may be slow. Partnerships with green builders, initial launches in smaller markets (e.g. EIFS

  16. NON-LINEAR TRANSIENT HEAT CONDUCTION ANALYSIS OF INSULATION WALL OF TANK FOR TRANSPORTATION OF LIQUID ALUMINUM

    Directory of Open Access Journals (Sweden)

    Miroslav M Živković

    2010-01-01

    Full Text Available This paper deals with transient nonlinear heat conduction through the insulation wall of the tank for transportation of liquid aluminum. Tanks designed for this purpose must satisfy certain requirements regarding temperature of loading and unloading, during transport. Basic theoretical equations are presented, which describe the problem of heat conduction finite element (FE analysis, starting from the differential equation of energy balance, taking into account the initial and boundary conditions of the problem. General 3D problem for heat conduction is considered, from which solutions for two- and one-dimensional heat conduction can be obtained, as special cases. Forming of the finite element matrices using Galerkin method is briefly described. The procedure for solving equations of energy balance is discussed, by methods of resolving iterative processes of nonlinear transient heat conduction. Solution of this problem illustrates possibilities of PAK-T software package, such as materials properties, given as tabular data, or analytical functions. Software also offers the possibility to solve nonlinear and transient problems with incremental methods. Obtained results for different thicknesses of the tank wall insulation materials enable its comparison in regards to given conditions

  17. Effects of Ceramic Fibre Insulation Thickness on Skin Formation and Nodule Characteristics of Thin Wall Ductile Iron Casting

    Science.gov (United States)

    Dhaneswara, D.; Suharno, B.; Nugraha, N. D.; Ariobimo, R. D. S.; Sofyan, N.

    2017-02-01

    Skin formation has become one of the problems in the thin wall ductile iron casting because it will reduce the mechanical properties of the materials. One of the solutions to reduce this skin formation is by using heat insulator to control the cooling rate. One of the insulators used for this purpose is ceramic fibre. In this research, the thickness of the ceramic fibre heat insulator used in the mould was varied, i.e. 50 mm on one side and 37.5 mm on the other side (A), no heat insulator (B), and 37.5 mm on both sides (C). After the casting process, the results were characterized in terms of metallography by using scanning electron microscope (SEM) and tensile test for mechanical properties. The results showed that the skin thickness formed in A is 34.21 μm, 23.38 μm in B, and 27.78 μm in C. The nodule count in A is 541.98 nodule/mm2 (84.7%) with an average diameter of 15.14 μm, 590 nodule/mm2 (86.7%) with an average diameter of 13.18 μm in B, and 549.73 nodule/mm2 (87.2%) with an average diameter of 13.95 μm in C. The average ultimate tensile strength for A was 399 MPa, B was 314 MPa, and C was 415 MPa. Microstructural examination under SEM showed that the materials have a ductile fracture with matrix full of ferrite.

  18. On the Detection of Building Exterior Wall Energy-saving Insulation Materials%建筑外墙节能保温材料检测浅析

    Institute of Scientific and Technical Information of China (English)

    吕志宏

    2015-01-01

    Based on the detection technology of building exterior wall energy-saving insulation materials, this article puts forward the method for the improvement of quality detection of energy saving insulation materials.%本文将立足建筑外墙节能保温材料的检测技术,提出完善节能保温材料质量检测的方法。

  19. Experimental Study on Thermal Performance of Externally Insulated Walls of Intermittent Air-Conditioned Rooms in Summer in Hot Summer and Cold Winter Region, China

    Directory of Open Access Journals (Sweden)

    Yong Ding

    2014-01-01

    Full Text Available Now requirements for the thermal performance of building walls are based on the assumption that heat flux transfers in one direction through the wall. However, in Hot Summer and Cold Winter Region of China, the direction of heat flow in the wall not only changes with the seasons, but also changes in the same period of using. In this paper, dynamic thermal process of externally insulated walls in different air-conditioner’s running state in summer in Chongqing, China, was tested. The distribution characteristics of the outdoor and indoor air temperature and the surface and inner temperatures of the wall were analyzed and demonstrated. Based on the unsteady-state heat transfer theory, the study calculated and analyzed the distribution characteristics of the direction of the heat flux in the thermal process. Also the characteristics of insulation and heat preservation for walls under different air-conditioner’s running state were analyzed. It is shown that, in any air-conditioner’s running state, the direction of the heat flux through the wall is obviously dynamically changing. There is obvious difference in the thermal performance needs of the wall; that is, it has strong demand for thermal insulation in daytime and strong demand for heat dissipation during night time in summer.

  20. Technology of building exterior wall thermal insulation material%建筑外墙保温材料防火性能技术探析

    Institute of Scientific and Technical Information of China (English)

    邓丽红

    2016-01-01

    近几年,随着我国经济建设的快速发展,各类高层新型建筑也伴随着社会发展和需要大量涌现,建筑的节能要求使得建筑外墙保温材料的使用量巨大。但几场由外墙保温材料引发的重特大火灾,使得政府有关部门认识到提高外墙保温材料防火性能要求的必要性,但如何将外墙保温材料的保温性与防火性有机的结合起来是个新的亟待解决的问题。本文通过分析建筑外墙保温材料的类型及其火灾危险性,结合当前建筑外墙保温材料的防火性能的现状,探析提高建筑外墙保温材料其防火性能的方法。%In recent years,with the rapid development of economic construction in our country,all kinds of tall new building is also accompanied by social development and needs large numbers,building energy-saving requirements makes the building external wall thermal insulation materials of the huge.But a few games by external wall thermal insulation material cause serious fire,the relevant government departments recognize the need to improve the external wall thermal insulation materials fire performance requirements,but how will the exterior wall thermal insulation material of thermal insulation and fireproof combining is a new urgent problems.In this paper,through the analysis of building exterior wall thermal insulation material type and fire hazard,combining with the building exterior wall thermal insulation material fire performance status,of building exterior wall thermal insulation material the fire performance of a method.

  1. Reconstruction of Full-Field Wall Pressure Fluctuations on a Flat Plate in the Wake of a Step Cylinder: Applications of Linear Stochastic Estimation (LSE)

    Science.gov (United States)

    Peng, Di; Chen, Yujia; Wang, Shaofei; Liu, Yingzheng; Wang, Weizhe

    2016-11-01

    Previous studies have shown that it is possible to reconstruct the full flow field based on time-resolved measurements at discrete locations using linear stochastic estimation (LSE). The objective of this study is to develop and apply this technique to wall pressure fluctuation measurements in low speed flows. Time-resolved wall pressure fluctuations on a flat plate in the wake of a step cylinder at low speed (V PSP). The microphone arrays are arranged properly to capture the dominant features in the flow field at 10 kHz. The PSP is excited using a continuous UV-LED, and the luminescent signal is recorded by a high-speed camera at 2 kHz. The microphone data at discrete locations are used to reconstruct the full-field wall pressure fluctuations based on LSE. The PSP results serve as basis for improvement of the LSE scheme and also for validation of the reconstructed pressure field. Other data processing techniques including proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) are also used for analyzing the unsteady flow features. This LSE technique has great potential in real-time flow diagnostics and control.

  2. Cellulose Insulation

    Science.gov (United States)

    1980-01-01

    Fire retardant cellulose insulation is produced by shredding old newspapers and treating them with a combination of chemicals. Insulating material is blown into walls and attics to form a fiber layer which blocks the flow of air. All-Weather Insulation's founders asked NASA/UK-TAP to help. They wanted to know what chemicals added to newspaper would produce an insulating material capable of meeting federal specifications. TAP researched the query and furnished extensive information. The information contributed to successful development of the product and helped launch a small business enterprise which is now growing rapidly.

  3. Insulated Concrete Form Walls Integrated With Mechanical Systems in a Cold Climate Test House

    Energy Technology Data Exchange (ETDEWEB)

    Mallay, D.; Wiehagen, J.

    2014-09-01

    Transitioning from standard light frame to a thermal mass wall system in a high performance home will require a higher level of design integration with the mechanical systems. The much higher mass in the ICF wall influences heat transfer through the wall and affects how the heating and cooling system responds to changing outdoor conditions. This is even more important for efficient, low-load homes with efficient heat pump systems in colder climates where the heating and cooling peak loads are significantly different from standard construction. This report analyzes a range of design features and component performance estimates in an effort to select practical, cost-effective solutions for high performance homes in a cold climate. Of primary interest is the influence of the ICF walls on developing an effective air sealing strategy and selecting an appropriate heating and cooling equipment type and capacity. The domestic water heating system is analyzed for costs and savings to investigate options for higher efficiency electric water heating. A method to ensure mechanical ventilation air flows is examined. The final solution package includes high-R mass walls, very low infiltration rates, multi-stage heat pump heating, solar thermal domestic hot water system, and energy recovery ventilation. This solution package can be used for homes to exceed 2012 International Energy Conservation Code requirements throughout all climate zones and achieves the DOE Challenge Home certification.

  4. Insulated Concrete Form Walls Integrated With Mechanical Systems in a Cold Climate Test House

    Energy Technology Data Exchange (ETDEWEB)

    Mallay, D. [Home Innovation Research Labs, Upper Marlboro, MD (United States); Wiehagen, J. [Home Innovation Research Labs, Upper Marlboro, MD (United States)

    2014-09-01

    Transitioning from standard light frame to a thermal mass wall system in a high performance home will require a higher level of design integration with the mechanical systems. The much higher mass in the ICF wall influences heat transfer through the wall and affects how the heating and cooling system responds to changing outdoor conditions. This is even more important for efficient, low-load homes with efficient heat pump systems in colder climates where the heating and cooling peak loads are significantly different from standard construction. This report analyzes a range of design features and component performance estimates in an effort to select practical, cost-effective solutions for high performance homes in a cold climate.

  5. PECULIARITIES OF DESIGN OF CURTAIN WALL SYSTEMS TO ASSURE THERMAL INSULATION

    Directory of Open Access Journals (Sweden)

    Golunov Sergej Anatolevich

    2012-10-01

    The results of laboratory tests (given the adjustments for permissible tolerances may be regarded as the principal criteria in the assessment of applicability of a curtain wall system in the course of a major building repair project or a new construction to assure the required reliability and durability.

  6. Investigation of the effects of pressure gradient, temperature and wall temperature ratio on the stagnation point heat transfer for circular cylinders and gas turbine vanes

    Science.gov (United States)

    Nagamatsu, H. T.; Duffy, R. E.

    1984-01-01

    Low and high pressure shock tubes were designed and constructed for the purpose of obtaining heat transfer data over a temperature range of 390 to 2500 K, pressures of 0.3 to 42 atm, and Mach numbers of 0.15 to 1.5 with and without pressure gradient. A square test section with adjustable top and bottom walls was constructed to produce the favorable and adverse pressure gradient over the flat plate with heat gages. A water cooled gas turbine nozzle cascade which is attached to the high pressure shock tube was obtained to measuse the heat flux over pressure and suction surfaces. Thin-film platinum heat gages with a response time of a few microseconds were developed and used to measure the heat flux for laminar, transition, and turbulent boundary layers. The laminar boundary heat flux on the shock tube wall agreed with Mirel's flat plate theory. Stagnation point heat transfer for circular cylinders at low temperature compared with the theoretical prediction, but for a gas temperature of 922 K the heat fluxes were higher than the predicted values. Preliminary flat plate heat transfer data were measured for laminar, transition, and turbulent boundary layers with and without pressure gradients for free-stream temperatures of 350 to 2575 K and flow Mach numbers of 0.11 to 1.9. The experimental heat flux data were correlated with the laminar and turbulent theories and the agreement was good at low temperatures which was not the case for higher temperatures.

  7. Relation between the Fluctuating Wall Pressure and the Turbulent Structure of a Boundary Layer on a Cylinder in Axial Flow

    Science.gov (United States)

    1993-08-12

    position sensing technique was employed that utilized one sensing device for the near-wall region (y < 0.18 in, y/8 < 0.191, y+ < 169) and a second...0.0005 in. that mounted on an external optical stand. The sensing device for the outer portions of the ’noundary layer was an Enco vernier caliper that...represern ±0. I 0 S S 6 0 S 0 0 0 4, 187 X), U00 3/8-in. -Diamneter Cylindrical ModelO .022-in.-O.D. ~ Stainless Steel Tube Brass 3/8 in. 0-Ring Half-Ring

  8. 机械自紧厚壁圆筒塑性半径的计算%Calculation of Plastic Radius for Thick-Walled Cylinders of Mechanical Autofrettage

    Institute of Scientific and Technical Information of China (English)

    常列珍; 潘玉田; 马新谋; 潘丹阳

    2011-01-01

    机械自紧是依靠冲头同身管内径的过盈量使身管内壁产生塑性变形,提高承载能力,达到自紧的目的.准确建立冲头过盈量与塑性半径之间的关系,才能准确地预测自紧度.为此,利用合理的简化假设,通过对冲头进行弹性分析和对厚壁圆筒进行塑性分析,利用机械自紧在加载过程中冲头圆柱段和厚壁圆筒接触处径向应力相等这一边界条件,推导出了过盈量与塑性半径之间的计算公式,从该公式可直接由过盈量求出塑性半径,由塑性半径便可预测出机械自紧厚壁圆筒的自紧度.为了验证公式的正确性,对10种不同过盈量的机械自紧过程进行了数值模拟,理论计算与数值模拟的结果进行比较,发现理论计算结果与数值模拟的结果比较吻合.%The swage autofrettage barrel is formed depending on the depth of plastic deformation since the diameter of the tool is slightly larger than the barrel inner diameter. The barrel forged in this way can withstand large internal pressures. In order to calculate the degree of autofrettage, the relation between the interference and the plastic radius must be accurately investigated. In loading process, the radial stress of cylindrical section of swage and thick-walled cylinder contact section is equal. By using this boundary condition, an elastic analysis for swage and a plastic analysis for thick-walled cylinder were conducted, and formulas were obtained for calculating excess and plastic radius. Knowing interference, the plastic radius could be calculated directly and the tight tolerance could be pre-estimated by using the plastic radius. To verify the accuracy of the formula, the process of mechanical autofrettage with ten kind different interferences were simulated. Calculated plastic radius agreed well with the results of numerical simulation.

  9. Effective measures for insulating, packing and reinforcing walls of mine workings

    Energy Technology Data Exchange (ETDEWEB)

    Postawa, J. [Akademia Gorniczo-Hutnicza, Cracow (Poland). Instytut Gornictwa Podziemnego i Bezpieczenstwa Pracy

    1992-12-31

    Discusses selected aspects of rock strata bonding used in underground black coal mines in Poland. The following types of acrylic resins are comparatively evaluated: SOLAKRYL M, SOLAKRYL ASM-10, SOLAKRYL SW, SORAKRYL SW-P. Their composition, chemical and physical properties are discussed. Composition of other conventional mixtures used for water influx control (grouting) and filling voids with expansive materials on a fly ash basis are evaluated. Use of acrylic resins for rock strata bonding, sealing porous sedimentary rocks and preventing quicksand intrusions is described. Use of resin injection and grouting in the following black coal mines is evaluated: the Jaworzno mine (water influx control), the Jan Kanty mine (sealing walls of a mine roadway and control of carbon dioxide emission), the Miechowice mine (sealing tubbings in a mine shaft), the Kazimierz Juliusz mine (repair of ventilation barriers).

  10. 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.

  11. Conductive cable fibers with insulating surface prepared by co-axial electrospinning of multi-walled nanotubes and cellulose

    Science.gov (United States)

    Miyauchi, Minoru; Miao, Jianjun; Simmons, Trevor J.; Lee, Jong-Won; Doherty, Thomas V.; Dordick, Jonathan S.; Linhardt, Robert J.

    2010-01-01

    A core-sheath of multi-walled carbon nanotube (MWNT)-cellulose fibers of diameters from several hundreds nm to several µm were prepared by co-axial electrospinning from a non-valatile, non-flammable ionic liquid (IL) solvent, 1-methyl-3-methylimidazolium acetate ([EMIM][Ac]). MWNTs were dispersed in IL to form a gel solution. This gel core solution was electrospun surrounded by a sheath solution of cellulose disolved in the same IL. Electrospun fibers were collected in a coagulation bath containing ethanol-water to completely remove the IL and dried to form a core-sheath MWNT-cellulose fibers having a cable structure with a conductive core and insulating sheath. Enzymatic treatment of a portion of a mat of these fibers with cellulase selectively removed the cellulose sheath exposing the MWNT core for connection to an electrode. These MWNT-cellulose fiber mats demonstrated excellent conductivity due to a conductive pathway of bundleled MWNTs. Fiber mat conductivity increased with increasing ratio of MWNT in the fibers with a maximum conductivity of 10.7 S/m obtained at 45 wt% MWNT loading. PMID:20690644

  12. Power transmission through double-walled laminated composite panels considering porous layer-air gap insulation

    Institute of Scientific and Technical Information of China (English)

    M H SHOJAEIFARD; R TALEBITOOTI; B RANJBAR; R AHMADI

    2014-01-01

    The acoustic behavior of double-walled laminated composite panels consisting of two porous and air gap middle layers is studied within the classical laminated plate theory (CLPT). Thus, viscous and inertia coupling in a dynamic equation, as well as stress transfer, thermal and elastic coupling of porous material are based on the Biot theory. In addition, the wave equations are extracted according to the vibration equation of composite layers. The transmission loss (TL) of the structure is then calculated by solving these equations simultaneously. Statistical energy analysis (SEA) is developed to divide the structure into specific subsystems, and power transmission is extracted with balancing power flow equations of the subsystems. Comparison between the present work and the results reported elsewhere shows excellent agreement. The results also indicate that, although favorable enhancement is seen in noise control particularly at high frequencies, the corresponding parameters associated with fluid phase and solid phase of the porous layer are important on TL according to the boundary condition interfaces. Finally, the influence of composite material and stacking sequence on power transmission is discussed.

  13. Experience summary of building of exterior wall thermal insulation construction%建筑物外墙保温施工经验总结

    Institute of Scientific and Technical Information of China (English)

    闫卫进

    2011-01-01

    通过工程实践,详细介绍了建筑物外墙保温材料的选择、设计及施工要求,并列举了外墙保温施工易产生的质量缺陷,同时给出了相应的处理方法,有效控制了施工质量,达到保温、节能的效果。%Through the engineering practice,the paper detailed introduced the selection,design and construction requirements of building of exterior wall thermal insulation material,and listed the easy to produce quality defects of external wall thermal insulation c

  14. Nonlinear transient heat transfer and thermoelastic analysis of thick-walled FGM cylinder with temperature-dependent material properties using Hermitian transfinite element

    Energy Technology Data Exchange (ETDEWEB)

    Azadi, Mohammad [Sharif University of Technology, Tehran (Iran, Islamic Republic of); Azadi, Mahboobeh [Shiraz University, Shiraz (Iran, Islamic Republic of)

    2009-10-15

    Nonlinear transient heat transfer and thermoelastic stress analyses of a thick-walled FGM cylinder with temperature dependent materials are performed by using the Hermitian transfinite element method. Temperature-dependency of the material properties has not been taken into account in transient thermoelastic analysis, so far. Due to the mentioned dependency, the resulting governing FEM equations of transient heat transfer are highly nonlinear. Furthermore, in all finite element analysis performed so far in the field, Lagrangian elements have been used. To avoid an artificial local heat source at the mutual boundaries of the elements, Hermitian elements are used instead in the present research. Another novelty of the present paper is simultaneous use of the transfinite element method and updating technique. Time variations of the temperature, displacements, and stresses are obtained through a numerical Laplace inversion. Finally, results obtained considering the temperature-dependency of the material properties are compared with those derived based on temperature independency assumption. Furthermore, the temperature distribution and the radial and circumferential stresses are investigated versus time, geometrical parameters and index of power law. Results reveal that the temperature-dependency effect is significant

  15. Design Tool for Cryogenic Thermal Insulation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Demko, Jonathan A [ORNL; Fesmire, J. E. [NASA Kennedy Space Center, Kennedy Space Center, Florida; Augustynowicz, S. D. [Sierra Lobo Inc., Kennedy Space Center, Florida

    2008-01-01

    Thermal isolation of low-temperature systems from ambient environments is a constant issue faced by practitioners of cryogenics. For energy-efficient systems and processes to be realized, thermal insulation must be considered as an integrated system, not merely an add-on element. A design tool to determine the performance of insulation systems for comparative trade-off studies of different available material options was developed. The approach is to apply thermal analysis to standard shapes (plane walls, cylinders, spheres) that are relatively simple to characterize with a one-dimensional analytical or numerical model. The user describes the system hot and cold boundary geometry and the operating environment. Basic outputs such as heat load and temperature profiles are determined. The user can select from a built-in insulation material database or input user defined materials. Existing information has been combined with the new experimental thermal conductivity data produced by the Cryogenics Test Laboratory for cryogenic and vacuum environments, including high vacuum, soft vacuum, and no vacuum. Materials in the design tool include multilayer insulation, aerogel blankets, aerogel bulk-fill, foams, powders, composites, and other insulation system constructions. A comparison of the design tool to a specific composite thermal insulation system is given.

  16. 外墙保温材料在工程中的选择与应用%Selection and Application of External Wall Thermal Insulation Materials in Engineering

    Institute of Scientific and Technical Information of China (English)

    崔路苗

    2015-01-01

    This paper illustrates the domestic status and trend of external wall thermal insulation materials and compares several commonly used ones.%概述了国内建筑外墙保温材料的应用现状和发展趋势,对几种常用的外墙保温材料的特点作了分析与比较.

  17. 谈寒冷地区外墙保温施工要点%On external wall heat insulation construction points in cold areas

    Institute of Scientific and Technical Information of China (English)

    张跃华

    2014-01-01

    In order to accelerate the circular economy and realize the social and economic sustainable development, the paper explores the exter-nal wall heat insulation construction technique in cold areas, analyzes the technical requirements for the external wall and heat insulation, illus-trates the selection principle for the external wall and exterior heat insulation materials, and points out the materials can meet the demands for the safe long-term stability and energy-saving long-term stability.%为加快发展循环经济,实现经济社会的可持续发展,对寒冷地区外墙保温施工技术进行了探讨,分析了外墙外保温的技术要求,阐述了外墙外保温材料的选择原则、方法,指出外墙保温材料应满足安全长期稳定、节能效果长期稳定等要求。

  18. Development tendency of exterior building wall greening and insulation system%建筑外墙绿化隔热系统之发展趋势

    Institute of Scientific and Technical Information of China (English)

    张华立; 李光范

    2012-01-01

    Through analyzing and comparing advantages and disadvantages of exterior building wall greening and insulation system at home and abroad, the essay explores the aspects needing improving of wall greening and insulation system with attached-type, external frame and separa- ted-type, climbing-type and planting desktop-type and the developing tendency. Based on existing two-dimensional exterior wall greening system, it puts forward prior covering-type multilevel vertical greening and insulation system.%通过对国内外建筑外墙绿化隔热系统优缺点的分析及比较,探讨了墙体附着式、外框架与墙体分离式、攀爬式和种植台式的墙体绿化隔热系统急需改进的方面和发展趋势,并在现有二维外墙绿化隔热系统上提出更为优越的覆盖式下的多层次垂直绿化隔热系统。

  19. 轻质保温隔墙板的制备及性能研究%Study on the Preparation and Properties of Lightweight Thermal Insulation Wall Panel

    Institute of Scientific and Technical Information of China (English)

    陈光剑; 陈珉; 张龙; 陈建良; 曾碧榕; 罗伟昂; 许一婷; 戴李宗

    2012-01-01

    建筑节能理念已受到普遍关注,轻质保温隔墙板作为一种节能材料且多功能化而成为研究开发的热点.由发泡聚苯乙烯(EPS)颗粒保温砂浆制备而成的芯材是轻质保温隔墙板的重要组成部分,对隔墙板性能起决定性作用.现有的保温隔墙板虽质轻,但强度较弱.为获得密度低、抗压强以及粘结性好的EPS保温砂浆芯材,以干表观密度对导热系数和抗压强度的影响为引导,研究了粉煤灰、发泡剂、甲基纤维素醚等对芯材抗压强度及粘结性能的作用规律;对芯材的压缩应力-应变曲线进行了分析,并讨论了增韧原因;初步试生产制得了综合性能良好的轻质保温隔墙板.%As energy-saving material, lightweight thermal insulation wall panel has been highly favored by the market and has received many interests because it has good performance such as sound insulation,easy construction and so on. The "core'part of lightweight thermal insulation wall panel was prepared by expanded polystyrene (EPS) insulation mortars.and it played a key role in improving performance of products. In order to obtain low density.high strength and high bond properties of EPS insulation mortar,the relationship between the dry apparent density of the core material with the thermal conductivity and compressive strength was investigated. The compressive stress-strain curve of the core material was analyzed and the reason for toughening was discussed. Finally, lightweight thermal insulation wall panel with good performance was produced by the given construction processing. Our research will be helpful for the development and industrialization of EPS insulation mortar with low density,high compressive strength and high bond properties.

  20. Drag and lift induced by the flow of viscoelastic fluids past a minute cylinder near a wall; Hekimen kinbo no bisho enchu wo sugiru nendansei ryutai no nagare ni yoru koryoku to yoryoku

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, H.; Hasegawa, T.; Narumi, T. [Niigata University, Niigata (Japan). Faculty of Engineering; Tamano, K. [Mitsubishi Electric Corp., Tokyo (Japan)

    1995-02-25

    In detergent engineering and polymer processing, it is important to study the force exerted on an obstacle placed near a wall. In the present study, we numerically analyze the flow of viscoelastic fluids past a minute cylinder which is set at or near an inside wall of a two-dimensional channel. The upper convected Maxwell model and the finite-element method are used as the constitutive equation and the numerical method, respectively. Drag and lift of the cylinder are calculated for low Reynolds numbers (Re) and various Weissenberg numbers (Wi) of positive and negative values. Drag coefficient (C{sub D}) slightly changes with Wi. Lift coefficient (C{sub L}) monotonously decreases with increasing Wi irrespective of the sign of Wi. C{sub L} is greatly changed with Wi and is more sensitive to the elasticity of the fluid than C{sub D}. C{sub D} and C{sub L} decrease as the cylinder is separated from the wall. 11 refs., 12 figs.

  1. 秸秆轻质墙体保温性能的研究%Research on Thermal-insulation Performance of Light Density Straw-based Wall

    Institute of Scientific and Technical Information of China (English)

    黄步庭; 徐青; 储文龙; 周定国

    2011-01-01

    The thermal performances of 5 different density straw-based light materials are evaluated by adopting the quasi-steady method.The thermal resistances of different combination walls are calculated by measuring their conductivity.Results show that straw-based light wall material can be used as lined insulation material for walls for its good insulation performance.Also,it can be uesed as non-bearing walls.%采用准稳态法,对不同密度规格的秸秆轻质墙体材料进行热性能测试.通过测试材料的导热系数,计算不同组合墙体的热阻.结果证明秸秆轻质墒体材料具有良好的保温性能,可以作为墙体内衬保温材料,以及非承重墙的墙体材料.

  2. Technology Solutions Case Study: Insulating Concrete Forms

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2012-10-01

    This Pacific Northwest National Laboratory project investigated insulating concrete forms—rigid foam, hollow walls that are filled with concrete for highly insulated, hurricane-resistant construction.

  3. Maximum Expected Wall Heat Flux and Maximum Pressure After Sudden Loss of Vacuum Insulation on the Stratospheric Observatory for Infrared Astronomy (SOFIA) Liquid Helium (LHe) Dewars

    Science.gov (United States)

    Ungar, Eugene K.

    2014-01-01

    The aircraft-based Stratospheric Observatory for Infrared Astronomy (SOFIA) is a platform for multiple infrared observation experiments. The experiments carry sensors cooled to liquid helium (LHe) temperatures. A question arose regarding the heat input and peak pressure that would result from a sudden loss of the dewar vacuum insulation. Owing to concerns about the adequacy of dewar pressure relief in the event of a sudden loss of the dewar vacuum insulation, the SOFIA Program engaged the NASA Engineering and Safety Center (NESC). This report summarizes and assesses the experiments that have been performed to measure the heat flux into LHe dewars following a sudden vacuum insulation failure, describes the physical limits of heat input to the dewar, and provides an NESC recommendation for the wall heat flux that should be used to assess the sudden loss of vacuum insulation case. This report also assesses the methodology used by the SOFIA Program to predict the maximum pressure that would occur following a loss of vacuum event.

  4. 夏热冬冷地区公共建筑外墙保温方案探索%External Wall Insulation Plan Exploration of Public Buildings in Hot Summer and Cold Winter Area

    Institute of Scientific and Technical Information of China (English)

    王其恒

    2012-01-01

    外墙保温是建筑保温的重要组成部分,外墙保温主要由墙身结构层和保温层来实现.结构层和保温层材料种类繁多,构造做法也不尽相同.通过分析各种外墙保温做法,总结各种做法的优缺点,并进行了深入的分析计算,最终确定了每种保温做法的合理适用范围.%External wall insulation is an important part of building insulation.Wall insulation mainly rely on wall body structure layer and the insulation layer to achieve.Structure layer and the insulation layer are composed of a wide variety of materials,construction practices are not the same.Through the analysis of all kinds of external wall insulation method,summarize the advantages and disadvantages of various methods,and conducted in-depth analysis,and ultimately determine the every kind of insulation for the reasonable application range.

  5. Effects of Different Walls on Thermal Insulation Properties of Solar Greenhouse%不同墙体日光温室保温性能研究

    Institute of Scientific and Technical Information of China (English)

    樊平声; 冯伟民; 卢昱宇; 陈罡; 管安琴; 苗彩霞; 陈兆翔

    2014-01-01

    为了确定合理的日光温室后墙材料与结构,2012年分别在睢宁、赣榆建造了不同墙体(普通空心砖墙、复合异质墙体、夹芯板墙体)构型的日光温室,并研究了不同墙体日光温室的增温、保温性能。结果表明:普通空心砖墙蓄热能力强,夜间保温效果好,但白天增温慢;夹芯板墙体热阻值大,白天升温较快,利于提高温室的最高温度,但夜间放热能力较弱,不利于夜间保温;复合异质墙体具有较好的热阻和蓄热能力,增温、保温性最佳。为使日光温室冬季获得较好增温保温效果,从节约成本方面考虑,建议选择1 cm内粉+24 cm空心砖+24 cm空心砖+10 cm聚苯乙烯泡沫塑料板+1 cm外粉为墙体的温室。%In order to choose reasonable material and structure for the back wall of solar greenhouse,dif-ferent walls,such as normal hollow brick wall,complex heterogeneous wall,and blockboard wall,were used to construct solar greenhouse in Suining and Ganyu County in 2012.And their warming and thermal insulation properties were studied.The results showed that the normal hollow brick wall had strong heat storage capacity, which existed good thermal insulation effect during the night,but it warmed up slowly during the day.The blockboard wall had bigger thermal resistance value and warmed up quickly during the day,which could boost the highest temperature in solar greenhouse,but it had low exothermal capacity,which existed poor thermal insulation effect during the night.The complex heterogeneous wall had good thermal resistance and heat stor-age capacities,which had the best warming and thermal insulation property.In order to obtain better warming and thermal insulation effects in winter and save cost,the wall with 1 cm inner calcimine,24 cm hollow brick,24 cm hollow brick,10 cm protection layer which was made of polystyrene foam board and 1 cm outer calcimine was the best choice.

  6. 49 CFR 178.45 - Specification 3T seamless steel cylinder.

    Science.gov (United States)

    2010-10-01

    ...) Type, size, and service pressure. A DOT 3T cylinder is a seamless steel cylinder with a minimum water... eliminate these defects provided the minimum wall thickness is maintained. (5) Welding or brazing on a cylinder is not permitted. (d) Wall thickness. The minimum wall thickness must be such that the wall...

  7. Analysis on construction technology of exterior insulation of building exterior wall%建筑外墙外保温施工技术解析

    Institute of Scientific and Technical Information of China (English)

    左敬宏

    2015-01-01

    Building energy efficiency has become the inevitable trend of the development of modern architecture, building exterior insulation construction technology can effectively achieve the building energy efficiency,promote the development of China’s building energy efficiency. Exterior insulation construction of building exterior wall requires the use of external wall material and the corresponding construction technology,which can meet the requirements of energy conservation.Therefore,the construction technology of external insulation construction can not only improve people’s quality of life,but also promote the improvement of energy efficiency.In view of the construction technology of exterior insulation construction technology of building exterior insulation, external insulation construction technology is studied,and put forward a reasonable solution to promote the development of China’s construction industry.%建筑节能化已经成为了现代建筑发展的必然趋势,建筑外墙的外保温施工技术可以有效的实现建筑节能,促进我国建筑节能化的发展。建筑外墙的外保温施工需要使用符合节能要求的外部墙体材料以及相应的施工技术,保证建筑物内部的能源利用效率得到有效的提高,达到建筑节能的目的。所以建筑外墙外保温施工技术不仅可以提高人们的生活质量,还能促进能源利用效率的提升。针对建筑外墙外保温施工技术的相关问题,对外保温施工技术进行研究,提出合理的解决措施,促进我国建筑行业的发展。

  8. 夏热冬冷地区建筑外墙保温材料和保温形式的发展趋势%The Development Trend of Exterior Wall Thermal Insulation Material and Thermal Insulation Form in Hot Summer and Cold Winter Zone

    Institute of Scientific and Technical Information of China (English)

    朱冰曲; 陈晓明; 王婧

    2013-01-01

    夏热冬冷地区围护结构设计需要同时考虑冬季保温与夏季隔热的问题,这对建筑的围护结构节能设计提出了较高的要求.在介绍常用的外墙保温材料性能和保温形式基础上,针对夏热冬冷地区的气候特征和建筑特点,进行外墙保温材料和保温形式的研究,指出在保温材料方面,复合保温材料结合了有机保温材料和无机保温材料各自的优点,在一定程度上解决了无机保温材料厚度较大而有机保温材料防火性能差的不足;在保温形式方面,建筑外墙内外组合保温和墙体自保温体系相结合是夏热冬冷地区保温形式的发展趋势,这种保温形式的实质就是保温材料与砌体相结合,共同实现建筑外围护综合保温的目的.%In hot summer and cold winter zone, retaining structure design should be considered thermal insulation in winter and heat insulation in summer together, so it has a higher design requirement of energy-saving. On the basis of introducing the performance of thermal insulation material and thermal insulation form commonly used for external wall, external wall insulation materials and insulation form were studied and their development trend was discussed according to the climate characteristics and the building features in hot summer and cold winter zone. Organic insulation materials are not good at fireproof performance, and inorganic insulation materials usually have large thickness. Composite insulation materials combine the respective advantages of both and to some extent, it tackles their deficiencies. According to thermal insulation form, development trend is to combine the two measures-one is mixing the internal and external insulation of exterior wall; another is self-insulation system of exterior wall. The essence of this thermal insulation form is the combination of thermal insulation material and brickwork, so it can realize the aim of integrated insulation for building envelope.

  9. STUDY ON FIRE RESISTANCE PERFORMANCE OF SEVERAL BUILDING' S EXTERIOR WALL INSULATION MATERIALS%几种建筑外墙保温材料的抗火性能分析

    Institute of Scientific and Technical Information of China (English)

    姚家伟; 侯兆铭; 姚亦舒

    2012-01-01

    在建筑节能外围护结构的保温隔热中,外墙体的保温隔热对建筑节能的影响最大.目前建筑外墙保温材料和保温技术需要具有优异的保温效果、杰出的耐燃性能、成熟的保温配套系统、便捷的施工方法、绿色环保和经济可行的材料.文中对几种传统的外墙保温材料和外墙保温新材料的性能进行了对比分析,从而推荐出保温与防火性能好的外墙保温材料,满足建筑工程需要.%In the external structure' s insulation, the outer wall insulation has the greatest impact on building energy efficiency. Currently building's exterior wall materials and insulation technology requires a superior insulation effect, outstanding fireproof performance, sophisticated insulation matching system, convenient construction methods, green and economically viable materials. In this paper, comparative a-nalysis has been carried on among several traditional insulation materials and new materials, which recommended a good thermal insulation and fireproof performance of exterior insulation materials to meet the construction needs.

  10. 49 CFR 178.38 - Specification 3B seamless steel cylinders.

    Science.gov (United States)

    2010-10-01

    ... cylinders welded or formed by spinning is, under no condition, to be less than two times the minimum wall...-pressure parts, and only to the tops and bottoms of cylinders having a service pressure of 500 psig or less... wall thickness. (m) Leakage test. All spun cylinders and plugged cylinders must be tested for leakage...

  11. Building elements and systems using vacuum insulated panels in external walling; Bauelemente und Systeme mit VIP fuer Aussenwandkonstruktionen

    Energy Technology Data Exchange (ETDEWEB)

    Binz, A.; Steinke, G.

    2008-07-01

    This illustrated report for the Swiss Federal Office of Energy (SFOE) takes a look at a research project concerning vacuum-insulated building elements and systems. The advantages of the thin vacuum insulation panels (VIP) are listed and compared with the increasingly thick layers of conventional insulation required for low energy consumption buildings that meet so-called 'passive house' standard. The aims of the research project are discussed which addressed the particular requirements placed on the materials and their protection against external damage. The monitoring of vacuum state using RFID chips is discussed. Various protective elements are examined. Also, facade constructions and the avoidance of thermal short circuits are discussed. Illustrated examples of applications are presented and developments in this fast-moving area are commented on.

  12. Exterior wall rock wool insulation construction technology of ceramic tile facing%外墙岩棉保温磁砖饰面施工技术

    Institute of Scientific and Technical Information of China (English)

    石海平

    2015-01-01

    the rock is basalt and other natural mineral as the main raw materials by high temperature melting into the fiber,adding proper amount of binder, good insulation, sound insulation,fire prevention effect. Rock wool construction and installation convenience,remarkable energy saving effect,has a very high price. In the construction process,we explored and summed up the wall rock wool insulation construction technology of ceramic tile facing,through the engineering practice,and achieved good economic and social benefits, and has broad application prospects.%岩棉是以玄武岩及其它天然矿石为主要原料经高温熔融成纤,加入适量粘接剂而成,具有良好的绝热、隔音、防火效果。岩棉施工及安装便利、节能效果显著,具有很高的性价比。在施工过程中,我们探索和总结出了外墙岩棉保温磁砖饰面施工技术,通过工程实践,取得了良好的经济效益和社会效益,具有广阔的应用前景。

  13. Radiation Insulation

    Science.gov (United States)

    1995-01-01

    The Apollo and subsequent spacecraft have had highly effective radiation barriers; made of aluminized polymer film, they bar or let in heat to maintain consistent temperatures inside. Tech 2000, formerly Quantum International Corporation used the NASA technology in its insulating materials, Super "Q" Radiant Barrier, for home, industry and mobile applications. The insulation combines industrial aluminum foil overlaid around a core of another material, usually propylene or mylar. The outer layer reflects up to 97 percent of heat; the central layer creates a thermal break in the structure and thus allows low radiant energy emission. The Quantum Cool Wall, used in cars and trucks, takes up little space while providing superior insulation, thus reducing spoilage and costs. The panels can also dampen sound and engine, exhaust and solar heat.

  14. 现浇轻质保温复合墙体施工技术%Construction of Cast-in-place Lightweight Thermal Insulation Composite Wall

    Institute of Scientific and Technical Information of China (English)

    黄旭腾; 杨庆泽

    2014-01-01

    Cast-in-situ lightweight composite insulation wall is erected with light steel keel and ce-ment pressure plate, pouring molding with the new lightweight rigid insulation materials. The new lightweight rigid insulation materials consist of a large amount of tailings, fly ash, boron mud and other in-dustrial waste as the main raw material for recycling. The wall technology with light steel keel in construc-tion industry, horizontal transfer and infiltration of the technical content are researched for determining the construction of cast-in-situ light composite insulation wall, enhancing technology of green environmental protection and energy saving, reducing waste emissions, solving environmental pollution, saving the land resources with good economic benefit and social benefit.%现浇轻质保温复合墙体是利用轻钢龙骨和水泥压力板支模后,现场浇入新型轻质刚性保温材料而制成的一次成型复合墙体,其中新型轻质刚性保温材料是以大量尾矿粉、粉煤灰、硼泥等工业废弃物作为主要原材料,通过可回收再利用,实现变废为宝。通过建筑行业轻钢龙骨墙体施工工艺,横向转移和渗透其技术内容,研究确定现浇轻质保温复合墙体的施工技术,推广应用绿色环保节能技术,减少废弃物排放,解决环境污染问题,节约土地资源,具有良好的经济效益和社会效益。

  15. Environmental assessment of insulation methods. Environmental data for insulation products and eco-profiles for light external walls; Miljoevurdering af isoleringsmetoder. Miljoedata for isoleringsprodukter og miljoeprofiler for lette ydervaegge

    Energy Technology Data Exchange (ETDEWEB)

    Krogh, K.; Rasmussen, J.O.; Nielsen, P.A.

    2001-07-01

    The project included selected insulation products like products made of cellulose fibres, flax fibres and perlite, which could all be used in external walls, internal walls, cavity walls and lofts. Up till now only products of mineral fibres were used. The aim of the project was to collect environmental data for selected products for the whole lifetime and to assess environmental impacts caused by the products. The total environmental impacts of a building element, e.g. external walla, were calculated from environmental data of the products. The impacts could be shown in a diagram, eco-profiles, which also showed contributions of the materials to the total impacts. The calculations used the principles of life cycle assessment (LCA), but today LCA does not include health aspects in the indoor climate or environmental health aspects caused by disposal processes. Therefore, this project included qualitative assessments for these two life cycle phases. The project did not treat impacts in the working environment as these health aspects are covered by other projects (COWI, 2000 and Engelund et al., 1999). (au)

  16. Study on the Energy-saving Wall Insulation Technology of Building%建筑节能墙体保温技术的研究

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    With the rapid growth of the economy, the problem of energy shortage in our country is becoming increasingly serious, energy conservation has become an important problem faced by modern society. Science and technology innovation of chemical enterprise makes the building energy-saving wal in China may be the thermal insulation material, the use of this material not only meet the requirements of environmental protection, but also reduces the construction cost. Based on the implementation of energy-saving wall insulation materials, this paper discusses the types of building energy-saving wal insul-ation technology, provides basis for the application of new ma-terials.%  随着经济的快速增长,我国的能源短缺问题日益严重,节能工作成为现代社会面临的重要问题。化工企业的科技革新使得我国的建筑节能墙体保温材料成为了可能,这种材料的使用不仅符合绿色环保的要求,也降低了施工工艺的成本。本文以节能墙体保温材料出发,探讨了建筑节能墙体保温技术的实施类型,为新材料的运用提出了基础。

  17. Base Stress of the Opened Bottom Cylinder Structures

    Institute of Scientific and Technical Information of China (English)

    刘建起; 孟晓娟

    2004-01-01

    The base stress of the opened bottom cylinder structure differs greatly from that of the structure with a closed bottom. By investigating the inner soil pressure on the cylinder wall and the base stress of the cylinder base, which were obtained from the model experiments, the interactions among the filler inside the cylinder,subsoil and cylinder are analyzed. The adjusting mechanism of frictional resistance between the inner filler and the wall of the cylinder during the overturning of the cylinder is discussed. Based on the experimental study, a method for calculating the base stress of the opened bottom cylinder structure is proposed. Meanwhile, the formulas for calculating the effective anti-overturning ratio of the opened bottom cylinder are derived.

  18. On problems in external wall thermal insulation of existing buildings and solutions%既有建筑外墙保温存在的问题及解决措施

    Institute of Scientific and Technical Information of China (English)

    温少瑜

    2015-01-01

    介绍了建筑外墙内保温与外保温的技术特点,对既有建筑外墙保温存在的材料不合格、施工质量不合格、住户使用不合理等问题进行了研究,给出了相应的解决措施,使外墙保温的效果符合国家和地方的节能要求。%The paper introduces the technical features for the internal and external thermal insulation of exterior walls of buildings, researches some problems including unqualified materials, construction quality and unreasonable residents’ usages in the external wall thermal insulation of existing buildings, and provides respective solutions, so as to ensure the external wall thermal insulation adheres to the national and regional ener-gy-saving requirements.

  19. Radiation levels on empty cylinders containing heel material

    Energy Technology Data Exchange (ETDEWEB)

    Shockley, C.W. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    Empty UF{sub 6} cylinders containing heel material were found to emit radiation levels in excess of 200 mr/hr, the maximum amount stated in ORO-651. The radiation levels were as high as 335 mr/hr for thick wall (48X and 48Y) cylinders and 1050 mr/hr for thin wall (48G and 48H) cylinders. The high readings were found only on the bottom of the cylinders. These radiation levels exceeded the maximum levels established in DOT 49 CFR, Part 173.441 for shipment of cylinders. Holding periods of four weeks for thick-wall cylinders and ten weeks for thin-wall cylinders were established to allow the radiation levels to decay prior to shipment.

  20. Preparation and Thermal Insulation Properties of External Wall Insulation Mortar System Using Solid Waste%基于废弃物利用的自保温墙体配套砂浆制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    孙林柱; 杨芳; 谢子令; 赵善宇; 徐海珣

    2012-01-01

    采用淤泥陶砂、废弃加气混凝土结合传热系数小的玻化微珠为砂浆骨料,基于“复合化”思想,制备自保温墙体配套砂浆.采用正交实验探讨混掺砂浆的合理配比,控制4项参数:胶凝材料用量、陶砂(或废料)与玻化微珠体积比、硅灰取代量和胶粉掺量,以干容重、抗压强度、导热系数为考核指标,制备综合利废效果最佳的新型混掺复合保温砂浆.结果表明,陶砂玻化微珠复合砂浆导热系数0.16~0.29 W/(m·K),随着陶玻比增大而增大,因此陶砂体积含量增加有利于提高保温性能,加气废料玻化微珠复合砂浆的导热系数0.10~1.14 W/(m·K),与陶砂复合保温砂浆相比,有较大的降低.%Combining with vitrified micro bubbles(VB) , sludge ceramic sand(SC) and abandon aerated concrete(AC) were chosen in the paper as aggregate. Together with cementitious materials, novel external wall insulation mortar was prepared. Based on orthogonal method, the experiment was designed with four parameters: cementing materials dosage, SC/VB or AC/VB ratio, silica fume replacement ratio and rubber replacement ratio, and three key performance indicators: dry bulk density, compressive strength and thermal conductivity were test to check the performance of mortar samples. After synthetical design of the test, hybrid insulation mortar with optimal parameters and performances were produced, the thermal conductivity of sludge ceramic sand mortar is 0. 16~0. 29 W/(m · K), and increasing with improvement of the SC/VB ratio, while thermal conductivity of abandon aerated concrete mortar is 0. 10~0. 14 W/(m · K), it is lower than sludge ceramic sand mortar. They are expected to be promising insulation materials for building thermal insulation use.

  1. Experimental Research on Heat Transfer Performance for Self-insulation Foam-concrete Wall%泡沫混凝土自保温墙体传热性能试验研究∗

    Institute of Scientific and Technical Information of China (English)

    王海军; 姚勇; 陈代果; 高伟; 严洁

    2015-01-01

    Foam⁃concrete was a building energy⁃saving material with many excellent performances such as lightweight, thermal insulation, sound insulation, fire, power consumption. Through testing the thermal defect and heat transfer performance of external⁃insulation, internal⁃insulation and self⁃insulation retaining walls, and analyzing these walls ’ heat transfer coefficient, thermal inertia indicator and eigenvalue on technical and economic with the building heat transfer theory, some conclusions are taken that:the external⁃insulation’ s barrier⁃effect for thermal⁃bridges was greater than internal⁃insulation, and foam⁃concrete self⁃insulation wall had the best indoor thermal⁃environment;foam⁃concrete’ s regenerative coefficients were greater than EPS insulation board, self⁃insulation wall had great thermal stability and resistance to external temperature fluctuations; foam⁃concrete self⁃insulation wall had good heat transfer performance, smaller eigenvalue on technical and economic which have a better marketing prospects.%泡沫混凝土是一种建筑节能材料,具有轻质、保温隔热、隔声、防火耗能等优异性能。通过对外保温、内保温和自保温围护墙体的热工缺陷、传热性能等进行测试,用建筑传热理论分析各类墙体的传热系数、热惰性指标和技术经济特征值,得出:外保温对热桥的阻隔作用大于内保温,泡沫混凝土自保温墙体室内热环境最好;泡沫混凝土蓄热系数大于EPS保温板,自保温墙体的热稳定性好,抵抗外部温度波动的能力强;泡沫混凝土自保温墙体传热性能良好,技术经济特征量较小,具有一定的市场应用前景。

  2. Economical Thermal Insulation Thickness on External Wall of Teaching Building in a University in Tianjin%天津地区某高校教学楼外墙保温层经济性厚度研究

    Institute of Scientific and Technical Information of China (English)

    周淑玲; 高辉

    2014-01-01

    以天津地区某高校教学楼为例,用Designbuilder7.2模拟分析其建筑外墙采用XPS挤塑聚苯板为保温层时的制冷及采暖的耗能量,分析保温层厚度与建筑能耗之间的变化关系;再基于生命周期成本分析法原理,建立材料费用、能耗费用以及保温层厚度之间的数学模型,得出该高校教学楼外墙保温层的经济性厚度,对保温层厚度计算方法的研究及寒冷地区外墙保温层的经济性厚度的选择均具有一定的意义。%Taking a university in Tianjin as an example, the cooling and heating energy consumption of building with external wall taking XPS as insulation layer is simulated with Designbuilder7.2 to study the relationship between thermal insulation thickness and energy consumption, to conclude the economical thickness of thermal insulation on external wall. The economical thermal insulation thickness on external wall is concluded by establishing mathematical model of material cost, energy cost and insulation thickness. The calculation for thermal insulation thickness and the selection of economical thermal insulation thick-ness on external wall in cold area are expounded.

  3. Sound Insulation Performance of Wood Structure Wall Filled with Ginkgo Tubular Particleboard%银杏木空心刨花板复合墙体隔声性能

    Institute of Scientific and Technical Information of China (English)

    周统建; 王志强; 徐才峰; 曹福亮

    2012-01-01

    在现代平台式轻型木结构墙体中分别填充30mm厚岩棉、33mm厚一层空心刨花板和33mm厚两层空心刨花板,形成三种不同的复合外墙,并测试三种墙体的隔声性能,得到了隔声效果的单一评价值.实验结果表明:空心刨花板复合墙体存在隔低频声差,隔高频声好的隔声特性.空心刨花板复合墙体隔声性能优于类似填实岩棉等吸声材料的墙体结构,而且其隔声性能(计权隔声量)都接近或超过40dB,符合住宅隔声标准要求.%The sound insulation performance of three kinds of wood structure wall was tested and their single-number quantity was got in this paper. The three kinds of wood structure wall were filled with three kinds of filler materials, such as 30 mm thick rock wool, 33 mm one-ply and 66 mm two-ply ginkgo tubular particle-board. The teat results showed that the wood structure wall filled with ginkgo tubular particleboard had better sound insulation in high frequency and lower sound insulation in low frequency. The wood structure wall filled with ginkgo tubular particleboard had better sound insulation than the wood structure wall filled with rock wool in the same structure, and the weight-counted sound insulation quantity was close to or more than 40 dB, which met the requirements of residential sound insulation standard.

  4. MHD convective flow through porous medium in a horizontal channel with insulated and impermeable bottom wall in the presence of viscous dissipation and Joule heating

    Directory of Open Access Journals (Sweden)

    K.V.S. Raju

    2014-06-01

    Full Text Available This paper deals with a steady MHD forced convective flow of a viscous fluid of finite depth in a saturated porous medium over a fixed horizontal channel with thermally insulated and impermeable bottom wall in the presence of viscous dissipation and joule heating. The governing equations are solved in the closed form and the exact solutions are obtained for velocity and temperature distributions when the temperatures on the fixed bottom and on the free surface are prescribed. The expressions for flow rate, mean velocity, temperature, mean temperature, mean mixed temperature in the flow region and the Nusselt number on the free surface have been obtained. The cases of large and small values of porosity coefficients have been obtained as limiting cases. Further, the cases of small depth (shallow fluid and large depth (deep fluid are also discussed. The results are presented and discussed with the help of graphs.

  5. Internal voltage in a conducting closed hollow cylinder with an attached end plate subjected to a direct lightning strike

    Energy Technology Data Exchange (ETDEWEB)

    Ong, M M; Anderson, R A

    2000-06-01

    The interior voltage of a large metal can with thick walls struck directly by lightning was estimated using diffusion theory, aperture slot voltage theory, and experimental data. The hollow cylinder is closed at both ends. One end has a cap that is welded to the cylinder wall making a continuous electrical interface. The other end consists of a circular plate that is pressed into the cylinder wall and held under pressure with a threaded ring. From our experience with coupling measurements, this joint will be a weak link. It will allow more current to leak into the interior than from diffusion through the walls. Because the joint was designed for mechanical purposes, the electrical properties, such as continuity around the circumference, are not well controlled. Therefore, it is difficult to determine a single voltage attributed to this joint design with varying electrical characteristics. Instead, we will make a best effort of bounding the problem using both analytical calculations and data from tests of similar structures. The calculated internal cylinder voltage subjected to an extreme lightning strike from current diffusing through the wall is 19 volts. We estimate that the press-fit end plate will increase this voltage by a factor of about two to ten. The internal voltage is expected to be between 40 and 200 volts. This uncertainty can be reduced by making coupling and high-current measurements on a number of cans or by redesigning the cap to include electrical contacts. However, given that the critical components inside the cylinder are insulated to at least 3.5 kV, improving the joint design is unnecessary. The safety factor using the worst-case maximum interior voltage is 18 and is sufficient. A higher safety margin can be achieved by keeping the joint clean and under pressure.

  6. Thermal shock in a circumferentially cracked hollow cylinder with cladding

    Science.gov (United States)

    Nied, H. F.

    1984-01-01

    An theoretical analysis is presented which demonstrates the effect of cladding on the thermal resistance of a circumferentially cracked hollow cylinder. The cladding is assumed to be bonded to the inner wall of the hollow cylinder. The axisymmetric circumferential crack may be either embedded in the cylinder wall or may be an edge crack which passes through the clad and opens into the inner wall of the hollow cylinder. The problem is formulated mathematically and a solution is found which is in the form of a single integral equation. The integral equation is solved numerically and yields estimates of transient temperature distributions, thermal stresses in the uncracked cylinder, and stress intensity factors as a function of time for various cladding thickness to cylinder wall thickness ratios. It is shown that yielding of the clad under certain conditions can result in a reduction in the magnitude of the stress intensity factor for the crack tip in the elastic base material.

  7. wall

    Directory of Open Access Journals (Sweden)

    Irshad Kashif

    2016-01-01

    Full Text Available Maintaining indoor climatic conditions of buildings compatible with the occupant comfort by consuming minimum energy, especially in a tropical climate becomes a challenging problem for researchers. This paper aims to investigate this problem by evaluating the effect of different kind of Photovoltaic Trombe wall system (PV-TW on thermal comfort, energy consumption and CO2 emission. A detailed simulation model of a single room building integrated with PV-TW was modelled using TRNSYS software. Results show that 14-35% PMV index and 26-38% PPD index reduces as system shifted from SPV-TW to DGPV-TW as compared to normal buildings. Thermal comfort indexes (PMV and PPD lie in the recommended range of ASHARE for both DPV-TW and DGPV-TW except for the few months when RH%, solar radiation intensity and ambient temperature were high. Moreover PVTW system significantly reduces energy consumption and CO2 emission of the building and also 2-4.8 °C of temperature differences between indoor and outdoor climate of building was examined.

  8. 外墙保温材料数值模拟研究%Study on numerical simulation of the vertical combustion characters for external wall thermal insulation materials

    Institute of Scientific and Technical Information of China (English)

    谢云飞; 朱国庆; 张磊; 王金争

    2012-01-01

    FDS (Fire Dynamics Simulator) was applied to simulate the vertical combustion of external wall thermal insulation material in this article. Firstly the parameters of EPS, XPS and PU were designated according to engineering preference and the fire source was provided by the window fire. After the simulating, those data were sorted. It was found that the height of flame changed in the form of nonlinear change: y = at2 + bt + c. The shape of trend line was a parabolic. The height of flame changed quickly in the earlier stage of simulating wih the later stage changing slowly. The velocity of flame front changed in the form of linear change:vp=αt + β. The velocity of flame front reduced stably in the simulating. XPS had the best thermal conductivity, so the temperature in each test point rised the most slowly. The EPS' temperature variation curve was the most stable in all with the best coefficient of thermal storage. The conclusion can provide certain prediction for the vertical combustion of actual external wall insulation material on the constructions and improve the efficiency of fire fighting and rescue for the fire department.%根据外墙保温材料具体的工程参数为依据,对挤塑型聚苯乙烯(XPS)、膨胀型聚苯乙烯(EPS)和聚氨酯(PU)三种材料的燃烧参数进行设定,设定火源为从窗口喷射而出的火焰,运用FDS软件进行数值模拟与分析.经过模拟发现:外墙保温材料在竖向燃烧中,火焰前锋高度呈现抛物线式增长,y=at2+bt+c,前期增长迅速,后期逐渐平稳.火焰前锋速度按照线性变化,vp=αt+β.在整个燃烧过程中,火焰前锋速度平稳的降低.XPS板导热系数最好,各测点的温度上升最慢,EPS板蓄热系数最好,所以其温度曲线最为平稳.

  9. 49 CFR 178.37 - Specification 3AA and 3AAX seamless steel cylinders.

    Science.gov (United States)

    2010-10-01

    ... cylinders welded or formed by spinning is, under no condition, to be less than two times the minimum wall... which are non-pressure parts, and only to the tops and bottoms of cylinders having a service pressure of... required, without cracking, to 6 times the wall thickness of the cylinder. (m) Leakage test. All spun...

  10. The prefabricated wall construction technology of PU edge compound board with color plate and rock wool insulation%PU 封边彩钢岩棉复合保温板装配式墙体施工技术

    Institute of Scientific and Technical Information of China (English)

    贾敬峰

    2015-01-01

    介绍了某钢结构厂房外墙采用聚氨酯涂层彩钢岩棉复合板自保温体系施工技术,通过应用墙面板材PU封边技术、对板式墙体节点处理进行了深化设计,并对该施工技术特点、质量标准控制进行了总结,指出该墙体具有保温、隔声性能良好、防水性能优越等优点。%This paper introduced a steel structure building exterior wall on the use of Polyurethane coating compound board with color plate and rock wool insulation system construction,through the application of PU edge on the wall plate,on the panel wall joint processing detailed design, application of the construction technology,summarizes the technical characteristics,quality control standard of the wall,with thermal insulation, sound insulation property,waterproof superior performance advantages.

  11. W-76 PBX 9501 cylinder tests

    Energy Technology Data Exchange (ETDEWEB)

    Hill, L.G.; Catanach, R.A.

    1998-07-01

    Five 1-inch diameter cylinder tests were fired in support of the W-76 high explosive surveillance program. Three of the tests used baseline material, and two used stockpile return material. The diagnostics were electrical pins to measure detonation velocity and a streak camera to measure wall motion. The data was analyzed for cylinder energy, Gurney energy, and detonation velocity. The results of all three measures were consistent for all five tests, to within the experimental accuracy.

  12. 新型建筑墙体材料及墙体保温技术%New Building Materials of Wall and Insulation Technology

    Institute of Scientific and Technical Information of China (English)

    赵磊

    2014-01-01

    随着经济发展,新型建筑企业在国家的建设中不断崛起。在建筑中,墙体的施工是整个建筑的重要环节。因此,对于新型墙体的需求量逐渐增多。施工人员对墙体材料应进行熟悉,熟悉墙体的保温技术,这是现代建筑的重--求。%With the development of economy, new cons- truction enterprises continue to rise in the country's construc- tion. In the building, wall construction is an important part of the whole building. Therefore, the need for the new materials for the wal is gradualy increased. It is required that Const- ruction workers should be familiar with the new wal materials and insulation technology in modern architecture.

  13. Seasonal shading of walls with transparent thermal insulation by means of prismatic panes; Saisonale Abschattung von transparent gedaemmten Waenden mit Hilfe von Prismenscheiben

    Energy Technology Data Exchange (ETDEWEB)

    Christoffers, D.; Kneser, P.; Schramm, U. [Institut fuer Solarenergieforschung GmbH Hameln/Emmerthal (ISFH), Emmerthal (Germany). Abt. Systemtechnik von Solaranlagen

    1998-02-01

    Using prismatic panes, a seasonal shading responsive to the sun`s position can be realized. Thus the solar gains from direct radiation can be closely matched to the annual pattern of the heating requirements of buildings. The panes are suitable for window or facade elements in applications which do not need transparency insulated walls. The direct radiation received on a vertical south-oriented facade is reduced to 10% on clear summer days, while 90% is transmitted on clear winter days. The paper reports on results from computer simulations and experiences from a one year field test. (orig.) [Deutsch] Mit Hilfe von Prismenscheiben kann eine sonnenstandsabhaengige, saisonale Verschattung realisiert werden. Damit lassen sich solare Gewinne aus direkter Einstrahlung sehr gut an den jaehrlichen Verlauf des Heizenergiebedarfs von Gebaeuden anpassen. Sie eignen sich als nach Sueden weisende Fenster- und Fassadenelemente vorzugsweise in Bereichen, die keinen freien Durchblick benoetigen, insbesondere auch fuer transparent gedaemmte Solarwaende. Die auf die Suedfassade treffende Direktstrahlung wird durch die Prismenscheibe an klaren Wintertagen auf etwa 90%, an klaren Sommertagen auf 10% reduziert. Der Beitrag beschreibt die Ergebnisse von Simulationsrechnungen und die Erfahrungen aus einem einjaehrigen Praxistest. (orig.)

  14. Aluminum powder impacts the properties of EPS insulation energy-saving wall panel%铝粉对EPS节能保温墙板性能的影响

    Institute of Scientific and Technical Information of China (English)

    周鹏杰; 倪修全

    2013-01-01

    EPS节能保温墙板是一种轻型且保温效果好的保温材料,若在制作过程中加入铝粉,铝粉参与水化产生的氢氧化钙反应,生成氢气泡,使混凝土内部形成许多蜂窝状的结构,能增强保温效果。但当掺入过量铝粉时,发气量过大,墙体内部孔隙率过大,将影响混凝土的抗压强度,为此需要对铝粉的掺量进行研究。%EPS insulation energy-saving wall panels is a kind of light and heat preservation materials with good effect, if adding aluminum powder in the production process, Aluminum can react with the hydration of calcium hydroxide and generate hydrogen bubble, and form a number of cellular structure Inside the concrete, which enhances the heat preservation effect. When mixed with excess aluminum powder, it will have too much gas, and the large porosity impacts the compressive strength of concrete. So to study the content of aluminum powder is needed.

  15. Construction technology of external wall of inorganic thermal insulation mortar%外墙无机保温砂浆的施工技术

    Institute of Scientific and Technical Information of China (English)

    赵晓芳

    2013-01-01

    The heat preservation sand syrup means to be strached a material mixture by the separated heat preservation material and the sand but becomes of and used for a kind of building material that constructs to construct a surface heat preservation layer.The outside wall has no machine heat preservation sand syrup to have to economize on energy benefit to discard, the heat preservation heat insulation, fire prevention defend a jelly and bear characteristicses, such as aging excellent function and cheap price...etc. and have extensive market demands.There is also the technique measure to close first in constructing the craft of construction.%  保温砂浆是指由阻隔型保温材料和砂浆材料混合而成的,用于构筑建筑表面保温层的一种建筑材料。外墙无机保温砂浆具有节能利废、保温隔热、防火防冻、耐老化的优异性能以及低廉的价格等特点,有着广泛的市场需求。在建筑施工的工艺上也有先关的技术措施。

  16. 住宅建筑的外墙保温节能施工技术研究%Study on construction technology of energy-saving insulation wall of residential building

    Institute of Scientific and Technical Information of China (English)

    胡玺建

    2015-01-01

    in the exterior wall in the construction process, the external wall thermal insulation energy-saving technology is one of the focus of the current construction units need to focus on.In order to effectively save energy, at the same time ensuring residential building residential comfort,should strengthen the research of energy-saving insulation construction technology.%在建筑外墙施工过程中,外墙外保温节能技术是当前建筑施工单位需要着重关注的焦点之一。为了有效节约能源,同时保证住宅建筑的居住舒适度,应该加强保温节能施工技术的研究。

  17. Prediction of External Corrosion for Steel Cylinders--2007 Report

    Energy Technology Data Exchange (ETDEWEB)

    Schmoyer, Richard L [ORNL

    2008-01-01

    Depleted uranium hexafluoride (DUF{sub 6}) is stored in over 62,000 containment cylinders at the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and at the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. Over 4,800 of the cylinders at Portsmouth were recently moved there from the East Tennessee Technology Park (ETTP) in Oak Ridge, Tennessee. The cylinders range in age up to 56 years and come in various models, but most are 48-inch diameter 'thin-wall'(312.5 mil) and 'thick-wall' (625 mil) cylinders and 30-inch diameter '30A' (including '30B') cylinders with 1/2-inch (500 mil) walls. Most of the cylinders are carbon steel, and they are subject to corrosion. The United States Department of Energy (DOE) manages the cylinders to maintain them and the DUF{sub 6} they contain. Cylinder management requirements are specified in the System Requirements Document (LMES 1997a), and the activities to fulfill them are specified in the System Engineering Management Plan (LMES 1997b). This report documents activities that address DUF{sub 6} cylinder management requirements involving measuring and forecasting cylinder wall thicknesses. As part of these activities, ultrasonic thickness (UT) measurements are made on samples of cylinders. For each sampled cylinder, multiple measurements are made in an attempt to find, approximately, the minimum wall thickness. Some cylinders have a skirt, which is an extension of the cylinder wall to protect the head (end) and valve. The head/skirt interface crevice is thought to be particularly vulnerable to corrosion, and for some skirted cylinders, in addition to the main body UT measurements, a separate suite of measurements is also made at the head/skirt interface. The main-body and head/skirt minimum thickness data are used to fit models relating minimum thickness to cylinder age, nominal thicknesses, and cylinder functional groups defined in terms of plant site, storage yard

  18. 轻质隔墙体隔声性能改善途径的分析%Analysis on the approaches of improving sound insulation performance of lightweight wall

    Institute of Scientific and Technical Information of China (English)

    陈庆帅; 冀志江; 陈继浩; 王静

    2011-01-01

    The sound insulation effect of the current commonly used lightweight wall is generally low,and it is difficult to meet the relevant requirements on living sound environment. The analysis results show that mainly factors affecting sound insulation capability include low surface density,resonance phenomenon,coincidence effects and sound bridges,etc. Accordingly the approaches to improve the sound insulation performance of lightweight wall are put forward: using the "mass-air-mass" structure, or using composite wall panels of different materials and surface densities,with intermediate airspace filling sound-absorbing material and shock absorber setting between two side plates.%目前使用较多的轻质隔墙体的隔声量普遍偏低,难以满足人居声环境的相关要求.分析表明,影响轻质隔墙体隔声能力的因素是面密度低、共振现象、吻合相应以及声桥等.改善轻质隔墙体隔声性能的途径有采用"板面-空腔-板面"结构,以及采用不同材质和面密度的墙板组合,中间空气层添加吸声材料,两侧板之间设置减震装置等措施.

  19. A New Method for Calculating Plastic Radius of Swage Autofrettage Thick-walled Cylinder%一种新的机械自紧厚壁圆筒塑性半径计算方法

    Institute of Scientific and Technical Information of China (English)

    常列珍; 潘玉田; 马新谋

    2011-01-01

    为推导一种新的机械自紧厚壁圆筒塑性半径的计算公式,首先采用ANSYS对不同摩擦系数的机械自紧进行数值模拟,发现摩擦系数对残余应力和塑性半径无影响,因此在推导塑性半径计算公式时可不考虑摩擦系数的影响;其次根据机械自紧过程中冲头圆柱段和厚壁圆筒接触处径向应力相等推导出了塑性半径的计算公式.利用该公式计算了9个不同模拟管的塑性半径,结果表明理论值与实验值吻合良好.该公式可根据过盈量求出塑性半径和自紧度,或者在已知自紧度的情况下确定过盈量.%To derive a new formula to calculate the plastic radius of autofrettaged thick-walled cylinder, some simulations were run for different friction coefficients. It was found that the friction coefficient did not influence the residual stress and plastic radius. Thus, it is unnecessary to consider the effect of the friction coefficient in deriving the new formula of plastic radius. Also, considered that the radial stress in contact section of swage and thick-walled cylinder are equal during the swage procedure, the formula of plastic radius was derived. By using the formula, the plastic radius of nine different tubes were calculated. It is shown that the theoretical values of plastic radius coincide with the experiment results better. This formula can be used to calculate the plastic radius and over strain according to the excess, or determine the excess according to the overstrain.

  20. 厚壁圆筒悬臂梁模糊PID振动控制仿真%Simulation of Fuzzy PID Control Used in Vibration of the Thick Wall Cylinder Cantilever Beam

    Institute of Scientific and Technical Information of China (English)

    孙海涛; 郭保全; 张延平; 柴刚

    2016-01-01

    针对厚壁圆筒悬臂梁的振动情况进行了分析和振动控制系统仿真,旨在为火炮身管振动控制研究提供理论指导。首先运用模态分析法对悬臂梁结构进行振动动力学分析,并建立了传感方程和压电作动方程。根据模糊控制理论,以压电传感器的输出电压V(t)和V(t)的变化率Vc(t)作为模糊PID控制器的输入变量,利用模糊控制规则在线对PID参数进行整定。通过Simulink建立了基于模糊PID控制器的悬臂梁振动控制模型,继而进行仿真。仿真结果表明,基于压电材料的模糊PID控制方法对厚壁圆筒悬臂梁的振动抑制作用非常有效。%In order to provide theoretical guidance for the study of the cannon gun tube vibration control, this paper analyzes the vibration of the thick wall cylinder cantilever beam and the simulation of vibration control system. Firstly, modal analysis is carried out on the cantilever beam structure vibration dynamics analysis, and the sensing equation and piezoelectric actuator equation is established. According to the theory of fuzzy control, with piezoelectric sensor output voltageV(t) andVc(t) which is the rate of change ofV(t) as the input variable of fuzzy PID controller, we set the PID parameter online through the fuzzy control rule. The dynamic control model based on the fuzzy PID controller is established based on Simulink. The sim-ulation results show that the method of the fuzzy PID controller based on the piezoelectric material is very effective when it is used in the suppression of the vibration of the thick wall cylinder cantilever beam.

  1. Flow-induced vibrations of two tandem cylinders in a channel

    Directory of Open Access Journals (Sweden)

    Jiang Ren-Jie

    2012-01-01

    Full Text Available We numerically studied flow-induced vibrations of two tandem cylinders in transverse direction between two parallel walls. The effect of the horizontal separation between two cylinders, ranging from 1.1 to 10, on the motions of the cylinders and the flow structures were investigated and a variety of periodic and non-periodic vibration regimes were observed. The results show that when two cylinders are placed in close proximity to each other, compared with the case of an isolated cylinder, the gap flow plays an important role. As the separation ratio is increased, the fluid-structure interaction decouples and the cylinders behave as two isolated cylinders.

  2. Condensation in insulated homes

    Energy Technology Data Exchange (ETDEWEB)

    Wiley, R A

    1978-05-28

    A research proposal on condensation in insulated homes is presented. Information is provided on: justification for condensation control; previous work and present outlook (good vapor barrier, condensation and retrofit insulation, vapor barrier decreases condensation, brick-veneer walls, condensation in stress-skin panels, air-conditioned buildings, retrofitting for conservation, study on mobile homes, high indoor relative humidity, report on various homes); and procedure (after funding has been secured). Measures are briefly described on opening walls, testing measures, and retrofitting procedures. An extensive bibliography and additional informative citations are included. (MCW)

  3. Investigation of breached depleted UF{sub 6} cylinders

    Energy Technology Data Exchange (ETDEWEB)

    DeVan, J.H. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)

    1991-12-31

    In June 1990, during a three-site inspection of cylinders being used for long-term storage of solid depleted UF{sub 6}, two 14-ton cylinders at Portsmouth, Ohio, were discovered with holes in the barrel section of the cylinders. An investigation team was immediately formed to determine the cause of the failures and their impact on future storage procedures and to recommend corrective actions. Subsequent investigation showed that the failures most probably resulted from mechanical damage that occurred at the time that the cylinders had been placed in the storage yard. In both cylinders evidence pointed to the impact of a lifting lug of an adjacent cylinder near the front stiffening ring, where deflection of the cylinder could occur only by tearing the cylinder. The impacts appear to have punctured the cylinders and thereby set up corrosion processes that greatly extended the openings in the wall and obliterated the original crack. Fortunately, the reaction products formed by this process were relatively protective and prevented any large-scale loss of uranium. The main factors that precipitated the failures were inadequate spacing between cylinders and deviations in the orientations of lifting lugs from their intended horizontal position. After reviewing the causes and effects of the failures, the team`s principal recommendation for remedial action concerned improved cylinder handling and inspection procedures. Design modifications and supplementary mechanical tests were also recommended to improve the cylinder containment integrity during the stacking operation.

  4. Research on Fire Safety Design of Thermal Insulation Materials Covering on Exterior Wall of Building%建筑外墙外保温材料防火安全的选型设计探讨

    Institute of Scientific and Technical Information of China (English)

    夏朝晖

    2011-01-01

    近年来,我国因建筑外墙外保温材料防火安全问题而导致特大火灾事故频发,尤其是上海胶州路教师公寓火灾、沈阳皇朝万鑫大厦火灾和北京央视大楼火灾,造成重大人员伤亡和财产损失,使得建筑外墙外保温材料防火安全成为人们关注的焦点.该文针对目前建筑外墙外保温材料选型设计中不注重防火安全的实际问题,分析了各种建筑外墙外保温材料防火性能,探讨其不同的使用局限性和优缺点,为建筑外墙外保温材料的选型设计提供参考.%In recent years the thermal insulation materials covering on the exterior wall for building fire safety problems caused the serious fire accidents, especially in the teacher apartment fire at Jiaozhou Road in Shanghai, the Dynasty wan Xin building fire in Shenyang and the CCTV building fire in Beijing, which caused the heavy casualties and the property losses, Therefore, the fire safety of the thermal insulation materials covering on the exterior wall has been a focus of attention.For solving the problem of the current moterials selection not paying attention to fire safety design, This paper analyzes the various fire performances of thermal insulation material covering on exterior wall, and their advantages and disadvantages, as a reference of selecting the thermal insulation material in the fire safety design.

  5. Analysis of a functionally graded piezothermoelastic hollow cylinder

    Institute of Scientific and Technical Information of China (English)

    CHEN Ying; SHI Zhi-fei

    2005-01-01

    A long thick-walled hollow cylinder ofpiezothermoelastic materials was studied in this work. The gradient property of the piezoelectric parameter g31 was taken into account. The theory of elasticity was applied to obtain the exact solutions of the cylinder subjected simultaneously to thermal and electric loadings. As an application, these solutions have been successfully used to study the inverse problems of the material. For comparison, numerical results have been carried out for both graded and double-layered cylinders.

  6. Theory of interacting dislocations on cylinders.

    Science.gov (United States)

    Amir, Ariel; Paulose, Jayson; Nelson, David R

    2013-04-01

    We study the mechanics and statistical physics of dislocations interacting on cylinders, motivated by the elongation of rod-shaped bacterial cell walls and cylindrical assemblies of colloidal particles subject to external stresses. The interaction energy and forces between dislocations are solved analytically, and analyzed asymptotically. The results of continuum elastic theory agree well with numerical simulations on finite lattices even for relatively small systems. Isolated dislocations on a cylinder act like grain boundaries. With colloidal crystals in mind, we show that saddle points are created by a Peach-Koehler force on the dislocations in the circumferential direction, causing dislocation pairs to unbind. The thermal nucleation rate of dislocation unbinding is calculated, for an arbitrary mobility tensor and external stress, including the case of a twist-induced Peach-Koehler force along the cylinder axis. Surprisingly rich phenomena arise for dislocations on cylinders, despite their vanishing Gaussian curvature.

  7. Improved DC Gun Insulator

    Energy Technology Data Exchange (ETDEWEB)

    M.L. Neubauer, K.B. Beard, R. Sah, C. Hernandez-Garcia, G. Neil

    2009-05-01

    Many user facilities such as synchrotron light sources and free electron lasers require accelerating structures that support electric fields of 10-100 MV/m, especially at the start of the accelerator chain where ceramic insulators are used for very high gradient DC guns. These insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic, creating a buildup of charge and causing eventual puncture. A novel ceramic manufacturing process is proposed. It will incorporate bulk resistivity in the region where it is needed to bleed off accumulated charge caused by highly energetic electrons. This process will be optimized to provide an appropriate gradient in bulk resistivity from the vacuum side to the air side of the HV standoff ceramic cylinder. A computer model will be used to determine the optimum cylinder dimensions and required resistivity gradient for an example RF gun application. A ceramic material example with resistivity gradient appropriate for use as a DC gun insulator will be fabricated by glazing using doping compounds and tested.

  8. Wall Energy Saving Technology and Construction Quality Control of the Exterior wall inner thermal insulation Proiect%建筑墙体节能技术与外墙内保温工程施工质量控制

    Institute of Scientific and Technical Information of China (English)

    黄振春

    2013-01-01

    随着全球环境的不断恶化以及各种资源的浪费,人们对节能环保的理念也越来越重视。而在建筑工程项目施工中,采用新技术新材料来达到节能降耗的目的,也已成为建筑单位与部门所关注的重点。本文就针对我国建筑工程中的墙体节能与外墙内保温技术的概念进行介绍,并详细分析其在建筑工程中的具体施工方法,再提出几点加强施工质量的控制措施,以期能够促进建筑节能的长效、可持久发展。%With the rapid development of our country's economy and the waste of resource , the environmental pollution has become more and more serious, and then people increasingly pay more attention to the energy -conservation and environment -protection.On the con-struction engineering projects , the new&high-tech materials are used for the purpose of the save energy and reduce consumption , it be-come the focuses of the construction units and departments .This article has focused on the EPS out -insulation engineering of save energy wall about the construction projects of China , and detailed analyzed the method in construction .Meanwhile, it offered a few points for the quality of materials and components of control measures , it's hoped to promote the energy effect and achieve sustainable development .

  9. Study on the external wall insulation system for fire prevention based on numerical simulation%基于数值模拟的外墙保温体系防火问题研究

    Institute of Scientific and Technical Information of China (English)

    赵平; 季经纬; 武爽

    2011-01-01

    针对国内现有的外墙外保温系统的防火性较差的现状,通过分析上海公寓楼外墙保温层的火灾,得到外墙外保温防火的三种重要因素(粘结或固定方式、防火隔离带的构造、防火保护面层).鉴于现在流行的保温材料为膨胀聚苯板(EPS),因而选用EPS作为模拟材料,利用数值模拟计算得出以下结论:认为火灾时有空腔的保温层比无空腔的保温层更危险;设置防火隔离带能有效得阻隔火灾的蔓延,较宽的隔离带效果更好.除此之外,外保温层防火设计中还应考虑以下三方面的问题,即遴选适当的保温材料、建议保温层也使用类似于防火分区的防火措施和保证保温效果的同时增加防火隔离带的宽度.研究结论和建议对于解决外墙保温体系防火问题具有重要的参考价值和现实意义.%Aiming at the status that the domestic existing exterior insulation system had poor fire resistance, through the analysis of apartment fire by exterior wall thermal insulation layer in Shanghai, three important factors exterior insulation fireproof were obtained induding binding or fixed mode, fire belt construction, fire protection layer. In view of the popular heat preservation material like EPS, it was selected to be the simulated material, and the following conclusions were obtained by numerical simulation: it was thought that in fire cavity insulation layer is more dangerous than no free cavity insulation; Setting fire belt can effectively block the spread of fire zone, and broader insulation belt has better effect. In addition, the design of insulation layer fire still should consider the following three problems, namely selecting proper insulation materials, suggesting insulation layer also use similar fire prevention measures liking fire compartment and increasing the midth of five bele at the same time of guaranteeing the thermal insulation. Research conclusions and recommendations for solving the

  10. Innovative Applications of New Wall Insulation Material in Green Design%公共建筑绿色设计中新型墙体保温材料的创新应用

    Institute of Scientific and Technical Information of China (English)

    王静; 韦冰; 周璐

    2012-01-01

    Wall materials are a key issue of green design of public buildings, New insulation materials which are derived from plant production waste achieve sustainable productions of raw materials. Then, application experiments is trying to explore how to transform effectively this material into public building insulation materials, and realize green performance of public buildings.%墙体材料是公共建筑绿色设计的关键问题.源于植物生产废弃物的新型保温材料,实现了原料生产的可持续.如何将这种材料有效转化为公共建筑的保温材料,实现公共建筑的绿色性能,还需要创新的应用实验来探索.

  11. Technical Improvements of Fire Resistance of Organic Insulation Materials for Building Exterior Wall%建筑外墙有机保温材料防火性能技术改进措施探索

    Institute of Scientific and Technical Information of China (English)

    沈丽华; 姚玉梅; 何一鸣

    2012-01-01

    The fire resistance of exterior wall organic insulation materials,such as molded polystyrene board(EPS) and polyurethane foam boards with different thickness plasters,were tested and the characteristics of these systems were studied,to explore the technical improvements of fire resistance of organic insulation materials.%主要对有机外墙外保温材料模塑聚苯板(EPS)和聚氨酯泡沫板在不同薄抹灰厚度的情况下进行了试验,研究其防火性能的特点,探索建筑外墙有机保温材料防火性能技术改进措施。

  12. UF{sub 6} pressure excursions during cylinder heating

    Energy Technology Data Exchange (ETDEWEB)

    Brown, P.G. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    As liquid UF{sub 6} inside a cylinder changes from a liquid to a solid, it forms a porous solid which occupies approximately the same volume as that of the liquid before cooling. Simultaneously as the liquid cools, UF{sub 6} vapor in the cylinder ullage above the liquid desublimes on the upper region of the inner cylinder wall. This solid is a dense, glass-like material which can accumulate to a significant thickness. The thickness of the solid coating on the upper cylinder wall and directly behind the cylinder valve area will vary depending on the conditions during the cooling stage. The amount of time lapsed between UF{sub 6} solidification and UF{sub 6} liquefaction can also affect the UF{sub 6} coating. This is due to the daily ambient heat cycle causing the coating to sublime from the cylinder wall to cooler areas, thus decreasing the thickness. Structural weakening of the dense UF{sub 6} layer also occurs due to cylinder transport vibration and thermal expansion. During cylinder heating, the UF{sub 6} nearest the cylinder wall will liquefy first. As the solid coating behind the cylinder valve begins to liquefy, it results in increased pressure depending upon the available volume for expansion. At the Paducah Gaseous Diffusion Plant (PGDP) during the liquefaction of the UF{sub 6} in cylinders in the UF{sub 6} feed and sampling autoclaves, this pressure increase has resulted in the activation of the systems rupture discs which are rated at 100 pounds per square inch differential.

  13. Homeowners' demand for home insulation

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-04-01

    The survey was conducted to provide guidance based on the views and experience of a national sample of homeowners about the insulation of their homes. The telephone survey was conducted with 1,012 homeowners between January 12 and 22, 1978 in the East, Midwest, South, and West regions of the U.S. From the survey data were compiled on plans for installing home insulation with emphasis on attic insulation; how many homes now have various types of insulation; recent experiences in obtaining attic insulation--its cost, material used, when installed, whether installed by the homeowner or a contractor; the kinds of insulation thought to be needed--attic insulation, wall insulation, storm doors and windows; whether homeowners planning attic insulation feel that they have the necessary information to do the work themselves or if they feel they know enough to make the necessary arrangements with a contractor; the effect of higher fuel costs on likelihood of installing attic insulation; shortages of insulating materials; what sources of information are relied on when planning attic insulation; attitudes toward having utility companies install insulation to be paid for by means of utility bills; how much trust homeowners have in the advice of government, utility companies, insulation manufacturers, insulation installers, and retail stores about how much insulation is needed; the likely effect of a tax credit on plans to insulate the attic; and the concern about energy shortages.

  14. 矿井固壁材料的保温性能研究%The Insulation Performance Study of Mine Solide Wall Materials

    Institute of Scientific and Technical Information of China (English)

    徐子芳; 葛雪祥; 陈娟

    2014-01-01

    针对玻化微珠保温砂浆在矿井内壁应用的局限性,利用单因素实验,并借助各种物理性能测试方法和扫描电镜(SEM)观察,分析了玻化微珠和超细粉煤灰在改善井下固壁砂浆导热性能、强度、耐久性等方面的作用。研究表明,玻化微珠保温轻骨料可有效改善砂浆的导热系数,但同时也会破坏材料的力学性能、耐候性能;超细粉煤灰可以改善材料的导热性、耐久性能以及孔结构,但掺量过多也会显著降低力学性能。保温砂浆的最优配合比是:2%玻化微珠、10%超细粉煤灰、2%可再分散乳胶粉、5%石灰以及1%石膏。%Considering the application limitations of glass beads insulation mortar inside shaft lining in mines, through the single-factor experiments and with the aid of various physical performance test and scanning electron microscopy (SEM) observation to analyze the role of each glass beads and ultraifne ash in the solid wall mortar ,which conclude the thermal conductivity, strength,durability and pore structure of mortar. The results showed that the adulteration of lightweight aggregate glazed hollow bead can effectively improve the thermal conductivity coefifcient, but it will also destroy the material properties of mechanical and weather resistance. The superifne lfy ash can not only improving the durability of the material, but the durability and pore structure. However, too much content can also signiifcantly reduce the mechanical properties. The optimal material mixture ratio determined to be: 2% glazed hollow bead, 10% ultra-ifne lfy ash, 2% re-dispersible powder, 5% lime and 1% gypsum.

  15. Prediction of External Corrosion for Steel Cylinders--2004 Report

    Energy Technology Data Exchange (ETDEWEB)

    Schmoyer, RLS

    2004-07-07

    Depleted uranium hexafluoride (UF{sub 6}) is stored in over 60,000 steel cylinders at the East Tennessee Technology Park (ETTP) in Oak Ridge, Tennessee, at the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and at the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The cylinders range in age from 4 to 53 years. Although when new the cylinders had wall thicknesses specified to within manufacturing tolerances, over the years corrosion has reduced their actual wall thicknesses. The UF{sub 6} Cylinder Project is managed by the United States Department of Energy (DOE) to safely maintain the UF{sub 6} and the cylinders containing it. This report documents activities that address UF{sub 6} Cylinder Project requirements and actions involving forecasting cylinder wall thicknesses. These requirements are delineated in the System Requirements Document (LMES 1997a), and the actions needed to fulfill them are specified in the System Engineering Management Plan (LMES 1997b). The report documents cylinder wall thickness projections based on models fit to ultrasonic thickness (UT) measurement data. UT data is collected at various locations on randomly sampled cylinders. For each cylinder sampled, the minimum UT measurement approximates the actual minimum thickness of the cylinder. Projections of numbers of cylinders expected to fail various thickness criteria are computed from corrosion models relating minimum wall thickness to cylinder age, initial thickness estimates, and cylinder subpopulations defined in terms of plant site, yard, top or bottom storage positions, nominal thickness, etc. In this report, UT data collected during FY03 is combined with UT data collected in earlier years (FY94-FY02), and all of the data is inventoried chronologically and by various subpopulations. The UT data is used to fit models of maximum pit depth and minimum thickness, and the fitted models are used to extrapolate minimum thickness estimates into the future and in

  16. Technical Status of Foam Insulation Material of External Wall and its Preparation with Sandstone Coal Gangue%外墙泡沫保温材料的技术现状及用砂岩质煤矸石试制

    Institute of Scientific and Technical Information of China (English)

    邢军; 李小庆; 孙晓刚; 邱景平

    2015-01-01

    砂岩质煤矸石和抛光砖泥都是工业固体废弃物,在国家提倡外墙保温材料革新升级和煤矸石资源化利用的背景下,开发煤矸石基外墙泡沫保温材料,既可以实现建筑节能和外墙的安全防火,又可以改善矿区生态环境,减少对宝贵土地资源的占用。在介绍了我国外墙保温材料产业现状和国内关于煤矸石基外墙泡沫保温材料研究现状的基础上,重点分析了试验原料的增塑性和发泡性,并进行了煤矸石基外墙泡沫保温材料的试制。结果表明,以辽宁朝阳矸石山砂岩质煤矸石和辽宁法库某陶瓷厂的抛光砖泥为主要原料,碳化硅和氧化镁为复合造孔剂,硼砂为助熔剂,经陈化—成型—烧结工序,试制出了具有一定外观和性能的煤矸石基外墙泡沫保温材料,说明本试验技术路线是可行的。但要制备满足建筑业要求的、低成本的外墙泡沫保温材料,还需后续进行系统的原料配比和烧结制度优化试验。%Under the background of external wall thermal insulation materials innovation upgrading and coal gangue re-source utilization,as industrial solid wastes,sandstone coal gangue and polishing tile waste are used to develop the external wall insulation foam material,which can achieve construction energy-efficient and fire safety,improve the ecological environment of mining area,and reduce the waste of valuable land resources. Based on the introduction of China's status of external wall insu-lation materials industry and research on coal gangue external wall foam insulation material,the plasticity and foaming of the tested material were analyzed,and the coal gangue exterior wall foam insulation material was prepared. The results show that, coal gangue exterior wall foam insulation material with a certain appearance and property can be produced through the aging, molding,and sintering process, with sandstone coal gangue in Chaoyang City and

  17. In-depth Study on Cylinder Wake Controlled by Lorentz Force

    Institute of Scientific and Technical Information of China (English)

    张辉; 范宝春; 陈志华

    2011-01-01

    The underlying mechanisms of the electromagnetic control of cylinder wake are investigated and discussed.The effects of Lorentz force are found to be composed of two parts,one is its direct action on the cylinder(the wall Lorentz force)and the other is applied to the fluid(called the field Lorentz force)near the cylinder surface.Our results show that the wall Lorentz force can generate thrust and reduce the drag; the field Lorentz force increases the drag.However,the cylinder drag is dominated by the wall Lorentz force.In addition,the field Lorentz force above the upper surface decreases the lift,while the upper wall Lorentz force increases it.The total lift is dominated by the upper wall Lorentz force.%The underlying mechanisms of the electromagnetic control of cylinder wake are investigated and discussed. The effects of Lorentz force are found to be composed of two parts, one is its direct action on the cylinder (the wall Lorentz force) and the other is applied to the fluid (called the field Lorentz force) near the cylinder surface. Our results show that the wall Lorentz force can generate thrust and reduce the drag; the Geld Lorentz force increases the drag. However, the cylinder drag is dominated by the wall Lorentz force. In addition, the field Lorentz force above the upper surface decreases the lift, while the upper wall Lorentz force increases it. The total lift is dominated by the upper wall Lorentz force.

  18. Cylinder monitoring program

    Energy Technology Data Exchange (ETDEWEB)

    Alderson, J.H. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    Cylinders containing depleted uranium hexafluoride (UF{sub 6}) in storage at the Department of Energy (DOE) gaseous diffusion plants, managed by Martin Marietta Energy Systems, Inc., are being evaluated to determine their expected storage life. Cylinders evaluated recently have been in storage service for 30 to 40 years. In the present environment, the remaining life for these storage cylinders is estimated to be 30 years or greater. The group of cylinders involved in recent tests will continue to be monitored on a periodic basis, and other storage cylinders will be observed as on a statistical sample population. The program has been extended to all types of large capacity UF{sub 6} cylinders.

  19. Facade insulation with mineral wool. Fassadendaemmung mit Mineralwolle

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-10-01

    Mineral wool insulations have proved worthwhile in construction engineering as apart from their very good thermal and sound insulating properties and they can be used nearly everywhere in construction as means of fire protection. With the passing of the 3rd Waermeschutzverordnung (regulation about thermal insulation) the requirements on the insulation of buildings have drastically increased. In this article insulation systems for external walls with mineral wool are described which are suited to meet also this new high insulation standard. (orig.)

  20. Prediction of External Corrosion for Steel Cylinders - 1998 Report

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, B.F.

    1998-01-01

    The United States Department of Energy (DOE) currently manages the UF, Cylinder Project. The project was formed to maintain and safely manage depleted uranium hexafluoride (UF{sub 6}) stored in approximately 50,000 carbon steel cylinders. The cylinders located at three DOE sites: the K-25 site at Oak Ridge, Tennessee (K-25); the Paducah Gaseous Diffusion Plant in Paducah, Kentucky (PGDP), and the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The System Requirements Document (SRD) (LMES 1997a) delineates the requirements of the project. The appropriate actions needed to fulfill these requirements are then specified within the System Engineering Management Plan (SEMP) (LMES 1997b). The report presented herein documents activities that in whole or in part satisfy specific requirements and actions stated in the UF{sub 6} Cylinder Project SRD and SEMP with respect to forecasting cylinder conditions. The wall thickness projections made in this report are based on the assumption that the corrosion trends noted will continue. Some activities planned may substantially reduce the rate of corrosion, in which case the results presented here are conservative. The results presented here are intended to supercede and enlarge the scope of those presented previously (Lyon 1995,1996, 1997). In particular, projections are made for thin-walled cylinders (nominal initial thickness 312.5 mils) and thick-walled cylinders (nominal initial thickness 625 mils). In addition, a preliminary analysis is conducted for the minimum thickness at the head/skirt interface for skirted cylinders.

  1. 建筑节能条件下外墙外保温技术在工程中的应用%Application of Thermal Insulation Technology of External Walls in Building Energy Conservation

    Institute of Scientific and Technical Information of China (English)

    赵强

    2015-01-01

    Thermal insulation of external walls is an important technology in building energy conservation. This paper illustrates the energy saving characteristics from three aspects:the necessity,the superiority and the structural system.%外墙外保温技术是建筑节能中一项重要的技术.从外墙外保温技术的必要性、优越性和结构体系等3个方面,阐述了其节能的性能特点.

  2. 预制夹芯保温墙体FRP连接件抗拔性能试验研究%PULL-OUT TESTS FOR EVALUATIONS OF ANTI-PULLING BEHAVIOR OF FRP CONNECTORS IN PRECAST SANDWICH INSULATION WALL PANELS

    Institute of Scientific and Technical Information of China (English)

    薛伟辰; 杨佳林; 王君若

    2012-01-01

    预制夹芯保温墙体是集承载与保温一体化的新型预制保温墙体.该墙体由内外叶钢筋混凝土板、中间保温层及纤维增强塑料(FRP)连接件组成,其中FRP连接件是连接内外叶钢筋混凝土板的关键部件,其受力性能直接影响墙体的安全性.本文以上海市某安居工程为背景,基于拔出试验对FRP连接件的抗拔承载力、破坏形态、荷载-滑移关系及荷载-应变关系等进行了较为系统的研究.研究表明,试件均发生了混凝土劈裂破坏;试件的抗拔承载力为23.5kN,为抗拔荷载设计值的14.3倍,满足工程设计要求,并具有较大的安全储备.最后,提出了预制保温墙体FRP连接件的抗拔承载力计算方法.%Precast sandwich insulation wall panel is a new type of insulation wall which performs well both in structural bearing and thermal insulation. This kind of wall is consisted of internal and external concrete wythes, insulating layers and the key component-FRP connectors, which ties two concrete wythes together to provide a distributed fastening system. Taking the model from a practical project in Shanghai as a reference, a series of tests including three pull-out specimens, with emphasis on FRP connectors' pull-out capacity, failure pattern and load-slip curve etc. , were presented. All the tests were terminated by the concrete fracture, and the average pull-out capacity of the connectors was 23. 5kN, about 14. 3 times of the design pull-out load. This means the connector could meet the requirements of the design in the practical project, and has a great safety margin as well. In addition, the calculation method to compute the pull-out capacity of FRP connectors in precast concrete sandwich wall is proposed.

  3. Application of External Wall Thermal Insulation Material in Building Energy-efficient%外墙保温材料在建筑节能中的运用

    Institute of Scientific and Technical Information of China (English)

    何学敏

    2014-01-01

    With the continuous development of building en-ergy-efficient technology, exterior wal thermal insulation technology has been developing. In the exterior wal thermal insulation technology, exterior wal thermal insulation material is very important. This article mainly expounds several kinds of exterior wal thermal insulation material used in exterior energy-efficient technology, and discusses the concrete app-lication of exterior wal thermal insulation in construction en-gineering.%随着建筑节能技术的发展,外墙保温技术也在不断发展中。在外墙保温技术中,外墙保温材料是非常重要的。本文主要阐述了建筑外墙节能技术中常用的几种外墙保温材料,并且探讨了外墙保温材料在建筑工程中的具体运用。

  4. RESULTS RESULTING FROM AUTOFRETTAGE OF CYLINDER

    Institute of Scientific and Technical Information of China (English)

    ZHU Ruilin

    2008-01-01

    Autofrettage is used to introduce advantageous residual stresses into wall of a cylinder and to even distributions of total stresses. Basic theory on autofrettage has been functioning for several decades. It is necessary to reveal profound relations between parameters in the theory. Therefore, based on the 3rd strength theory, δei/δy, δei/δy, δei′/δy, δei′/δy and their relations, as well as p/δy, are studied under ideal conditions, where δei/δy is equivalent stress of total stresses at elastoplastic juncture/yield strength, δei/δy is equivalent stress of total stresses at inside surface/yield strength, δei′/δy is equivalent stress of residual stresses at elastoplastic juncture/yield strength, δei′/δy is equivalent stress of residual stresses at inside surface/yield strength, p/δy is load-bearing capacity of an autofrettaged cylinder/yield strength. Theoretical study on the parameters results in noticeable results and laws. The main idea is: to satisfy |δei′|=δy, the relation between kj and k is , where k is outside/inside radius ratio of a cylinder, kj is ratio of elastoplastic juncture radius to inside radius of a cylinder; when the plastic region covers the whole wall of a cylinder, for compressive yield not to occur after removing autofrettage pressure, the ultimate k is k=2.218 46, with k=2.218 46, a cylinder's ultimate load-bearing capacity equals its entire yield pressure, or =lnk; when kj≤=1.648 72, no matter how great k is, compressive yield never occurs after removing pa; the maximum and optimum load-bearing capacity of an autofrettaged cylinder is just two times the loading which an unautofrettaged cylinder can bear elastically, or , thus the limit of the load-bearing capacity of an autofrettaged cylinder is also just 2 times that of an unautofrettaged cylinder.

  5. Construction technology of waterproofing and insulation in spraying rigid polyurethane foam on external wall%外墙喷涂聚氨酯硬泡体防水保温一体化施工技术

    Institute of Scientific and Technical Information of China (English)

    付国永

    2012-01-01

      Rigid polyurethane foam is a new type of building material. Rigid polyurethane foam external wall insulation system is a thermal insulation system with excellent properties, which can achieve 65 % of energy conservation. This article describes characteristics, structure, construction process and construction technology of rigid polyurethane foam external thermal insulation system.%  聚氨酯硬泡体是一种新型建筑材料。聚氨酯硬泡体外墙外保温系统是技术先进、性能优良的保温体系,其应用和推广对于实现65%的节能目标具有重要意义。针对喷涂法介绍聚氨酯硬泡体外墙防水保温一体化系统的特点、构造、施工流程和施工工艺等。

  6. Approximation by Cylinder Surfaces

    DEFF Research Database (Denmark)

    Randrup, Thomas

    1997-01-01

    We present a new method for approximation of a given surface by a cylinder surface. It is a constructive geometric method, leading to a monorail representation of the cylinder surface. By use of a weighted Gaussian image of the given surface, we determine a projection plane. In the orthogonal...

  7. 高层建筑典型外墙保温材料火蔓延特性数值模拟研究%Simulation of Fire Spread of Typical External Wall Insulation Materials in High-rise Building

    Institute of Scientific and Technical Information of China (English)

    章涛林; 周晓冬; 雷杲; 汪文君; 龚俊辉; 杨立中

    2012-01-01

    有机保温材料被广泛应用于高层建筑外墙保温体系的同时,也可能增加高层建筑的火灾风险.本文通过计算机模拟,着重研究了保温材料之一的聚苯乙烯泡沫塑料(EPS)的火蔓延速率、失重速率及温度场分布等特性.研究结果发现:发生火灾后,外墙保温材料可以在很短的时间内自下而上蔓延至整个材料表面,并有表皮着火的现象.在火焰到达材料顶部之前,向上火蔓延占主导地位,材料中部区域明显燃烧脱落,火焰在材料两端上部继续燃烧,有向下加速蔓延的趋势;之后,火焰沿着材料中部内侧向下剧烈燃烧,材料呈V字型燃烧直至熄灭.在高层建筑外墙外保温材料火蔓延中,不同着火点情况下的燃烧速率随时间变化的趋势相似,且会形成两个波峰.%Organic insulation materials are widely used in the external wall insulation system of high-rise buildings, but it also increases the risk of external wall fire. This paper, based on computer simulation, focuses attention mainly on the fire spread rate, mass loss rate, temperature distribution and other characteristics of one of the insulation materials Expanded Polystyrene (EPS). The study found that after the ignition of the external insulation material, in a very short period of time, fire spreads to the entire surface from bottom up, and has a feature of skin burning. Upward fire spread dominates before it reached the top of the material. The central region of the material was remarkably burned off. While the upper ends of the material continued to burn, accelerating the trend of downwards spread, then fire spreads downwards intensely along the middle of inside material and materials burned into a V-shape until extinguished. The burning rate curve is similar under different ignition points as to the fire spread of external insulation materials in high-rise building, forming two peaks.

  8. On the New Technology of Using Perlite for Insulation Layer of External Wall%谈外墙保温层利用珍珠岩的新工艺

    Institute of Scientific and Technical Information of China (English)

    曾笳

    2013-01-01

      建筑行业中资源消耗减量化、污染排放量最小化、废物再生资源化和无害化是今后发展的必然趋势。文章介绍了外墙保温技术的优点,探讨利用珍珠岩作为外墙保温层的新工艺的施工流程和施工要点,为该行业提供参考。%Resource consumption reduction, pollution emissions minimization, material regeneration and harmless, all of them in the construction industry are a certain trend in the future. The paper introduces the advantages of thermal insulation tech-nology in exterior wall, explores construction process and construction points of the new technology that use the perlite as the thermal insulation layer of external wall, providing some references for the field.

  9. Key Technology of the Prefabricated External Integrated Wall-panels with Decoration and Insulation%结构装饰保温一体化预制外墙板制造关键技术

    Institute of Scientific and Technical Information of China (English)

    杨思忠; 任成传; 齐博磊; 武卫平

    2015-01-01

    Based on the realistic need of construction project of public housing in Beijing, the structure characteristics of external integrated wall⁃panels with decoration and insulation are fully considered. Quality problems easily occurring in the construction including the precise positioning of filling sleeve, the choice of the connected components of internal and external wall, the choice of insulation layer, the construction of outer wall with decorative surface and hoisting embedded parts and so on are analyzed in detail. The corresponding solutions have been proposed, and the good results have been achieved.%结合北京市公租房工程建设,从结构装饰保温一体化外墙板的结构特点出发,对灌浆套筒精确定位、内外叶墙拉接件选用、保温层选用、装饰面外叶墙施工以及吊装预埋件等施工中容易出现的质量问题进行了详细分析,提出了针对性解决措施,取得了良好成效。

  10. An Approach to Stability Analysis of Embedded Large-Diameter Cylinder Quay

    Institute of Scientific and Technical Information of China (English)

    王元战; 祝振宇

    2002-01-01

    The large-diameter cylinder structure, which is made of large successive bottomless cylinders placed on foundationbed or partly driven into soil, is a recently developed retaining structure in China. It can be used in port, coastal and off-shore works. The method for stability analysis of the large-diameter cylinder structure, especially for stability analysis ofthe embedded large-diameter cylinder structure, is an important issue. In this paper, an idea is presented that is, em-bedded large-diameter cylinder quays can be divided into two types, i.e. the gravity wall type and the cylinder pile walltype. A method for stability analysis of the large-diameter cylinder quay of the cylinder pile wall type is developed and amethod for stability analysis of the large-diameter cylinder quay of the gravity wall type is also proposed. The effect of sig-nificant parameters on the stability of the large-dianeter cylinder quay of the cylinder pile wall type is investigated throughnumerical calculation.

  11. EFFECT OF MOISTURE ABSORPTION PROPERTIES OF INSULATION MATERIAL ON ENERGY CONSUMPTION OF COLD STORAGE WALL%保温材料的吸湿特性对冷库能耗的影响

    Institute of Scientific and Technical Information of China (English)

    罗金凤; 苏向辉

    2012-01-01

    基于一维非稳态热湿耦合模型,利用有限差分法对模型进行数值求解,针对保温材料的热导率为常数以及热导率为温湿度的函数这两种情况,分别使用苯板(EPS)、挤塑聚苯乙烯泡沫板(XPS)、聚氨酯(PU)作为保温层时,对冷库全年总能耗进行了比较.结果表明:保温材料吸湿会增大其热导率,从而大大增加了冷库总能耗,且保温层分别为XPS,PU,EPS时冷库全年总耗电量分别增加了5009.7kW·h,5492.6kW·h,8547.3 kW·h.%A numerical calculation by Finite Difference Method was presented based on a transient 1-D mathematical model of heat and mass transfer. The comparison of heat performance of cold storage wall was performed for three kinds of insulation materials: expanded polystyrene (EPS), extruded polystyrene (XPS), polyurethane (PU) in the case of the heat conductivity of insulation material is constant and the function of temperature and moisture. The results showed that the heat conductivity is larger when considering the absorption of moisture of the insulation material so that the energy consumption of cold storage is larger. The power consumption of cold storage increases 5 009.7kW·h, 5492.6kW·h, 8 547.3kW·h respectively when using XPS, PU, EPS as the insulation materials within a year.

  12. 外墙保温材料研究现状与进展%Research advances in thermal insulation materials used for external wall

    Institute of Scientific and Technical Information of China (English)

    朱清玮; 武发德; 赵金平

    2012-01-01

    Thermal insulation in huilding is one of the effective means which achieves not only energy-saving but also environmental protection. Exterior insulation is sorely recommended in building at present. Exterior insulation material can be divided into organic and inorganic materials with different advantages and disadvantages. In this paper.the research and application ad vance of various exterior insulation materials were introduced. The inorganic insulation materials will be developed more rapidly in the near future in the area of building materials due to the fact they are more environment-friendly and nonflammable compared to the organic ones. But the moisture resistance and strength need to be further improved.%建筑保温作为建筑节能的有效手段之一,将实现能源与环保“双赢”.外墙外保温是目前大力推广的一种建筑保温节能技术.外墙外保温材料可分为有机与无机保温材料2种,不同的保温材料具有不同优势与缺陷.对不同外墙外保温材料的研究与应用现状进行了阐述.与有机保温材料相比较而言,无机不燃保温材料将是未来环保型防火保温建材的一个重要发展方向,但其耐水性和强度还有待进一步改善.

  13. Tandem Cylinder Noise Predictions

    Science.gov (United States)

    Lockhard, David P.; Khorrami, Mehdi R.; CHoudhari, Meelan M.; Hutcheson, Florence V.; Brooks, Thomas F.; Stead, Daniel J.

    2007-01-01

    In an effort to better understand landing-gear noise sources, we have been examining a simplified configuration that still maintains some of the salient features of landing-gear flow fields. In particular, tandem cylinders have been studied because they model a variety of component level interactions. The present effort is directed at the case of two identical cylinders spatially separated in the streamwise direction by 3.7 diameters. Experimental measurements from the Basic Aerodynamic Research Tunnel (BART) and Quiet Flow Facility (QFF) at NASA Langley Research Center (LaRC) have provided steady surface pressures, detailed off-surface measurements of the flow field using Particle Image Velocimetry (PIV), hot-wire measurements in the wake of the rear cylinder, unsteady surface pressure data, and the radiated noise. The experiments were conducted at a Reynolds number of 166 105 based on the cylinder diameter. A trip was used on the upstream cylinder to insure a fully turbulent shedding process and simulate the effects of a high Reynolds number flow. The parallel computational effort uses the three-dimensional Navier-Stokes solver CFL3D with a hybrid, zonal turbulence model that turns off the turbulence production term everywhere except in a narrow ring surrounding solid surfaces. The current calculations further explore the influence of the grid resolution and spanwise extent on the flow and associated radiated noise. Extensive comparisons with the experimental data are used to assess the ability of the computations to simulate the details of the flow. The results show that the pressure fluctuations on the upstream cylinder, caused by vortex shedding, are smaller than those generated on the downstream cylinder by wake interaction. Consequently, the downstream cylinder dominates the noise radiation, producing an overall directivity pattern that is similar to that of an isolated cylinder. Only calculations based on the full length of the model span were able to

  14. Building America Top Innovations 2012: Basement Insulation Systems

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2013-01-01

    This Building America Top Innovations profile describes research on basement insulation, which identifies the wall installation methods and materials that perform best in terms of insulation and water resistance.

  15. Insulated Masonry Cavity Walls. Proceedings of the Research Correlation Conference by the Building Research Institute, Division of Engineering and Industrial Research. (April 1960).

    Science.gov (United States)

    National Academy of Sciences - National Research Council, Washington, DC.

    Publication of conference paper texts include --(1) history and development of masonry cavity walls, (2) recent research related to determination of thermal and moisture resistance, (3) wall design and detailing, (4) design for crack prevention, (5) mortar specification characteristics, (6) performance experience with low-rise buildings, (7)…

  16. Antennas on circular cylinders

    DEFF Research Database (Denmark)

    Knudsen, H. L.

    1959-01-01

    antenna in a circular cylinder. By a procedure similar to the one used by Silver and Saunders, expressions have been derived for the field radiated from an arbitrary surface current distribution on a cylinder surface coaxial with a perfectly conducting cylinder. The cases where the space between the two...... cylindrical surfaces have the sane characteristic constants and different constants are treated separately. Extensive numerical computations of the field radiated from the slot antennas described here are being carried out, but no numerical results are yet available...

  17. Heat-Insulating Performance of Straw-bale Wall Solar Greenhouse%秸秆块墙体日光温室保温蓄热性能分析

    Institute of Scientific and Technical Information of China (English)

    武国峰; 徐跃定; 常志州; 孙恩惠; 黄红英

    2015-01-01

    The purpose of this paper was to analysis the heat-insulating performance of solar greenhouse with straw-bale. A hollow brick wall was also evaluated as a control. The air temperature, the temperature at indoor and outdoor wall surface, at 5 cm depth of wall, soil tem-perature at different depth, and interface temperature were monitored and discussed. The results showed that the straw-bale wall has better thermal insulation properties than the hollow brick wall on both sunny and cloudy days. The dispersing heat in the hollow brick wall was 1.5 times greater than that in the straw-bale wall at night on sunny day, and 1.3 times greater than that in straw-bale wall at night on cloudy day. The lowest air temperature in straw-bale wall and hollow brick wall solar greenhouse were 5.4℃and 5.8℃on cloudy day, and 6.0℃and 7.4℃on sunny day, respectively. The air temperature in the hollow brick wall was higher than that in the straw-bale wall because of lower heat-storage performance of the hollow brick. The average soil temperature in straw-bale wall solar greenhouse(14.00±2.61)℃was higher than that in the hollow brick wall(13.55±1.73)℃. All the interface temperatures were influenced by the solar radiation intensity. The heat was stored in the soil and air in straw-bale wall solar greenhouse. The thermal storage ability of soil(above 10 cm)and air in straw-bale wall greenhouse was larger than that in hollow brick wall, while the thermal storage ability of straw-bale wall greenhouse was smaller than that of the hollow brick wall. The present paper provides the advantages and disadvantages of these two wall types of solar greenhouse, which would help improve the technique of straw-bale wall solar greenhouse.%为研究以农作物秸秆为墙体材料的日光温室(以下称秸秆块墙体日光温室)的保温蓄热性能,以秸秆块墙体日光温室为研究对象,以空心砖墙体日光温室为对照,监测了两种墙体材料温室中空气、

  18. Stability of Flow around a Cylinder in Plane Poiseuille Flow

    Science.gov (United States)

    Dou, Hua-Shu; Ben, An-Qing; Fluid Mechanics Research Team

    2013-11-01

    Simulation of Navier-Stokes equations is carried out to study the stability of flow around a cylinder in plane Poiseuille flow. The energy gradient method is employed to analyze the mechanism of instability of cylinder wake. The ratio of the channel width to the cylinder diameter is 30, and the Reynolds number based on the cylinder diameter and incoming centerline velocity is 26 and 100, respectively. The incoming flow is given as being laminar. It is found that the instability of the cylinder wake, starting near the front stagnation point upstream. The recirculation zone behind the cylinder has no effect on the stability of the wake. In the wake behind the recirculation zone, the flow stability is controlled by the energy gradient in the shear layer along the two sides of the wake. At high Re, the energy gradient of averaged flow in the channel interacts with the wake vortex, strengthening the wake vortex structure. Due to the large ratio of the channel width to the cylinder diameter, the disturbance caused by the cylinder mainly occurs in the vicinity of the centerline and has little effect on the flow near the wall. The velocity profile on the two sides of the cylinder wake in the downstream channel remains laminar (parabolic profile). Professor in Fluid Mechanics; AIAA Associate Fellow.

  19. Organic Insulation Materials, the Effect on Indoor Humidity, and the Necessity of a Vapor Barrier

    DEFF Research Database (Denmark)

    Rode, Carsten

    1998-01-01

    is not needed when using organic insulation materials" and "Organic insulation materials have a stabilizing effect on the indoor humidity".The paper presents some numerical analyses of the hygrothermal behavior of wall constructions and the occupied spaces they surround when an organic insulation material...... either inorganic or organic insulation materials in the surrounding walls....

  20. Thermal insulator

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, R.; Asada, Y.; Matsuo, Y.; Mikoda, M.

    1985-07-16

    A thermal insulator comprises an expanded resin body having embedded therein an evacuated powder insulation portion which consists of fine powder and a container of film-like plastics or a film-like composite of plastics and metal for enclosing the powder. The resin body has been expanded by a Freon gas as a blowing agent. Since a Freon gas has a larger molecular diameter than the constituent gases of air, it is less likely to permeate through the container than air. Thus present invention provides a novel composite insulator which fully utilizes the benefits of vacuum insulation without necessitating a strong and costly material for a vacuum container.

  1. High-Performance Slab-on-Grade Foundation Insulation Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Louise F. [NorthernSTAR, St. Paul, MN (United States); Mosiman, Garrett E. [NorthernSTAR, St. Paul, MN (United States)

    2015-09-01

    A more accurate assessment of slab-on-grade foundation insulation energy savings than traditionally possible is now feasible. This has been enabled by advances in whole building energy simulation with 3-dimensional foundation modelling integration at each time step together with an experimental measurement of the site energy savings of SOG foundation insulation. Ten SOG insulation strategies were evaluated on a test building to identify an optimum retrofit insulation strategy in a zone 6 climate (Minneapolis, MN). The optimum insulation strategy in terms of energy savings and cost effectiveness consisted of two components: (a) R-20 XPS insulation above grade, and, (b) R-20 insulation at grade (comprising an outer layer of R-10 insulation and an interior layer of R-12 poured polyurethane insulation) tapering to R-10 XPS insulation at half the below-grade wall height (the lower half of the stem wall was uninsulated).

  2. Research Status and Application of External Wall Thermal Insulation Materials%建筑外墙外保温材料的研究与应用

    Institute of Scientific and Technical Information of China (English)

    胡验君; 苏振国; 杨金龙

    2012-01-01

    概述了建筑外墙目前常用保温材料的使用性能、应用状况和存在问题,包括有机类的EPS、XPS、PU、PF和无机类的岩棉、泡沫玻璃(陶瓷)、泡沫混凝土.有机保温材料具有低的导热系数,保温性能好,但是易燃、防火等级低,安全性差,需要进行阻燃处理;无机保温材料不燃,防火等级高,安全性能好,但是保温性能不如有机保温材料,需要开发低导热系数的无机保温材料.最后指出,导热系数低、综合性能优异的无机保温材料将成为未来建筑保温材料的首选.%The functional performance, application situation, and problems of commonly used building exterior insulation materials are summarized, which includes organic kind (EPS, XPS, PU, PF) and inorganic kind (rock wool, foam glass, foam concrete). The advantages of organic heat preservation materials are low coefficient of thermal conductivity and good heat preservation performance. However, these materials have flammability, low fire rating, bad safety performance, and the need for flame retardant treatment. While, inorganic heat preservation materials have nonflammability, high fire rating, and good safety performance. Nonetheless, their thermal insulation properties are not as superior as organic heat preservation materials. Therefore, researchers need to develop low coefficient of thermal conductivity of inorganic heat preservation materials. As a result, relying on its low coefficient of thermal conductivity and outstanding comprehensive performance, inorganic thermal insulation materials will become the best choice of building insulation materials in the future.

  3. Approximation by Cylinder Surfaces

    DEFF Research Database (Denmark)

    Randrup, Thomas

    1997-01-01

    We present a new method for approximation of a given surface by a cylinder surface. It is a constructive geometric method, leading to a monorail representation of the cylinder surface. By use of a weighted Gaussian image of the given surface, we determine a projection plane. In the orthogonal...... projection of the surface onto this plane, a reference curve is determined by use of methods for thinning of binary images. Finally, the cylinder surface is constructed as follows: the directrix of the cylinder surface is determined by a least squares method minimizing the distance to the points...... in the projection within a tolerance given by the reference curve, and the rulings are lines perpendicular to the projection plane. Application of the method in ship design is given....

  4. 浅析建筑工程外墙保温设计%Analysis of Construction of Exterior Wall Insulation Design

    Institute of Scientific and Technical Information of China (English)

    陈芳

    2014-01-01

    Exterior wal insulation design is important project in energy-saving technology design. Because of the large prop-ortion of building exterior wal and also has a great influence on the energy-ef icient building performance, so exterior wal insulation design is the most efficient design in building en-ergy-saving. This article details construction of exterior wal insulation design.%外墙保温设计是建筑节能设计中的重要项目。由于建筑中外墙所占比例大,对建筑的节能性能影响也大,所以建筑工程的节能设计最有效的就是外墙保温设计。本文主要以建筑工程中外墙保温设计为基本点,对其进行了详细地分析。

  5. Upgraded Analytical Model of the Cylinder Test

    Energy Technology Data Exchange (ETDEWEB)

    Souers, P. Clark; Lauderbach, Lisa; Garza, Raul; Ferranti, Louis; Vitello, Peter

    2013-03-15

    A Gurney-type equation was previously corrected for wall thinning and angle of tilt, and now we have added shock wave attenuation in the copper wall and air gap energy loss. Extensive calculations were undertaken to calibrate the two new energy loss mechanisms across all explosives. The corrected Gurney equation is recommended for cylinder use over the original 1943 form. The effect of these corrections is to add more energy to the adiabat values from a relative volume of 2 to 7, with low energy explosives having the largest correction. The data was pushed up to a relative volume of about 15 and the JWL parameter ω was obtained directly. The total detonation energy density was locked to the v=7 adiabat energy density, so that the Cylinder test gives all necessary values needed to make a JWL.

  6. Upgraded Analytical Model of the Cylinder Test

    Energy Technology Data Exchange (ETDEWEB)

    Souers, P. Clark [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center; Lauderbach, Lisa [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center; Garza, Raul [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center; Ferranti, Louis [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center; Vitello, Peter [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center

    2013-03-15

    A Gurney-type equation was previously corrected for wall thinning and angle of tilt, and now we have added shock wave attenuation in the copper wall and air gap energy loss. Extensive calculations were undertaken to calibrate the two new energy loss mechanisms across all explosives. The corrected Gurney equation is recommended for cylinder use over the original 1943 form. The effect of these corrections is to add more energy to the adiabat values from a relative volume of 2 to 7, with low energy explosives having the largest correction. The data was pushed up to a relative volume of about 15 and the JWL parameter ω was obtained directly. Finally, the total detonation energy density was locked to the v = 7 adiabat energy density, so that the Cylinder test gives all necessary values needed to make a JWL.

  7. 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.

  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, 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.

  9. Hard sphere packings within cylinders.

    Science.gov (United States)

    Fu, Lin; Steinhardt, William; Zhao, Hao; Socolar, Joshua E S; Charbonneau, Patrick

    2016-03-07

    Arrangements of identical hard spheres confined to a cylinder with hard walls have been used to model experimental systems, such as fullerenes in nanotubes and colloidal wire assembly. Finding the densest configurations, called close packings, of hard spheres of diameter σ in a cylinder of diameter D is a purely geometric problem that grows increasingly complex as D/σ increases, and little is thus known about the regime for D > 2.873σ. In this work, we extend the identification of close packings up to D = 4.00σ by adapting Torquato-Jiao's adaptive-shrinking-cell formulation and sequential-linear-programming (SLP) technique. We identify 17 new structures, almost all of them chiral. Beyond D ≈ 2.85σ, most of the structures consist of an outer shell and an inner core that compete for being close packed. In some cases, the shell adopts its own maximum density configuration, and the stacking of core spheres within it is quasiperiodic. In other cases, an interplay between the two components is observed, which may result in simple periodic structures. In yet other cases, the very distinction between the core and shell vanishes, resulting in more exotic packing geometries, including some that are three-dimensional extensions of structures obtained from packing hard disks in a circle.

  10. Development of insulating coatings for liquid metal blankets

    Energy Technology Data Exchange (ETDEWEB)

    Malang, S.; Borgstedt, H.U. [Kernforschungszentrum Karlsruhe GmbH (Germany); Farnum, E.H. [Los Alamos National Lab., NM (United States); Natesan, K. [Argonne National Lab., IL (United States); Vitkovski, I.V. [Efremov Inst., St. Petersburg (Russian Federation). MHD-Machines Lab.

    1994-07-01

    It is shown that self-cooled liquid metal blankets are feasible only with electrically insulating coatings at the duct walls. The requirements on the insulation properties are estimated by simple analytical models. Candidate insulator materials are selected based on insulating properties and thermodynamic consideration. Different fabrication technologies for insulating coatings are described. The status of the knowledge on the most crucial feasibility issue, the degradation of the resisivity under irradiation, is reviewed.

  11. Application of Glazed Hollow Bead in Exterior Insulation of Antique Building’s Exterior Wall%玻化微珠在仿古建筑外墙外保温中的应用

    Institute of Scientific and Technical Information of China (English)

    杨卫敬; 韩阳

    2016-01-01

    With the national requirements of building’s exterior insulation are more stringent, building’s exterior wall materials are developing rapidly. Antique building materials are widely used in the actual engineering project because of energy efficiency and heat consumption reduction. Antique buildings not only meet national traditional plane combinations and facade designs, but also comply with modern architectural related design regulation. To choose a suitable thermal insulation material has been a focused issue. After the correlation analysis and performance comparison of different antique building materials, glazed hollow bead is proved to be one suitable material for antique building insulation.%随着国家对建筑外墙保温的要求愈趋严格,建筑节能材料的发展十分迅速。因节能材料具有节省能源、降低热量消耗的作用,在实际工程项目中的应用十分广泛。仿古建筑不仅要满足中国传统的平面组合方式及立面造型,同时,还必须符合现代建筑设计相关规范。为仿古建筑选择合适的保温材料一直是人们关注的热点。通过对仿古建筑外墙外保温材料选择的相关分析,及各种保温材料的性能对比,得出玻化微珠保温砂浆是目前较适合仿古建筑的保温材料。

  12. 脱硫石膏基胶凝材料用于保温墙体的探糾%Exploration of desulfurization gypsum cementitious materials used for thermal insulation wall

    Institute of Scientific and Technical Information of China (English)

    孔文栋; 薛力梨; 李强; 潘佳林

    2014-01-01

    将火力发电厂产生的脱硫石膏,粉煤灰两大废弃物以及另一种废弃物粉煤灰以一定比例混合制成胶凝材料,并与废弃的泡沫玻璃边角料复合制备成保温板,研究其强度、导热系数和表观密度等性能,并分析应用前景。结果表明:制得的保温板抗压强度在1.8MPa以上,导热系数在0.12-0.14w/(m.k)之间,干表观密度最小可以达到900kg/m3.。制得保温板成本低廉、保温性好,应具有良好的应用前景。%The coal-fired power plant desulfurization gypsum, two large waste, fly ash, and another kind of waste, to a certain proportion of fly ash to make cement materials and waste foam glass compound preparation into insulation board, examines the strength, thermal conductivity and apparent density, such as performance, and study its market prospects. Experiments prove that the compressive strength of insulation board above 1.8 MPa, the coefficient of thermal conductivity between 0.12 to 0.14 W/(m.k), dry apparent density minimum can reach 900 kg/m3.Because of new thermal insulation wall materials manufacture simple, low cost, good heat preservation, should have a good application prospect.

  13. Moisture Research - Optimizing Wall Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Arena, Lois [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Mantha, Pallavi [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States)

    2013-05-01

    In this project, the Consortium for Advanced Residential Buildings (CARB) team evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls. Wall assemblies evaluated included code minimum walls using spray foam insulation and fiberglass batts, high R-value walls at least 12 in. thick (R-40 and R-60 assemblies), and brick walls with interior insulation.

  14. Oscillatory Magnetohydrodynamic Natural Convection of Liquid Metal between Vertical Coaxial Cylinders

    Directory of Open Access Journals (Sweden)

    Fateh Mebarek-Oudina

    2016-01-01

    Full Text Available A numerical study of oscillatory magnetohydrodynamic (MHD natural convection of liquid metal between vertical coaxial cylinders is carried out. The motivation of this study is to determine the value of the critical Rayleigh number, Racr for two orientations of the magnetic field and different values of the Hartmann number (Harand Haz and aspect ratios A. The inner and outer cylinders are maintained at uniform temperatures, while the horizontal top and bottom walls are thermally insulated. The governing equations are numerically solved using a finite volume method. Comparisons with previous results were performed and found to be in excellent agreement. The numerical results for various governing parameters of the problem are discussed in terms of streamlines, isotherms and Nusselt number in the annuli. The time evolution of velocity, temperature, streamlines and Nusselt number with Racr, Har, Haz, and A is quite interesting. We can control the flow stability and heat transfer rate in varying the aspect ratio, intensity and direction of the magnetic field.

  15. Application of Value Engineering ill the Selection of Insulation Material of External Wall%价值工程在外墙保温材料选择中的应用

    Institute of Scientific and Technical Information of China (English)

    韦毅

    2011-01-01

    The principle of value engineering is applied in the selection of insulation material of external wall. The system functional diagram is constructed by functional analysis, and then evaluation method of value engineering is used for analysis and calculation. At last, the scheme with the highest value coefficient is determined to maximize the value.%本文将价值工程原理引入到外墙保温材料的选择中,通过功能分析,构建功能系统图,运用价值工程中的评价方法进行分析计算,确定价值系数最高的方案,实现价值最大化.

  16. Non-net casting exterior thermal insulation system on field concrete exterior wall in high storeyed resident building%高层住宅现浇混凝土外墙无网浇合外保温体系

    Institute of Scientific and Technical Information of China (English)

    顾同曾; 夏祖宏; 邸占英

    2001-01-01

    The non - net casting exterior thermal insulation system on field concrete exterior wall in high storeyed resident building is developed firstly at home. This system adopts polystyrene board without steel wire net as thermal insulation board. The cracking resistant layer consists of polymer cement mortar and alkali resistant glass fiber woven scrim, anchored with plastic expanded tube. The tests of bonding power between polystyrene board and concrete, plastic expanded tube pull- out, compressibility, freeze resistance show the system property is reliable and high safe. The thermal measurement test shows the system can meet the requirement of wall body energy - saving 50% stipulated in Beijing "Energy Saving Detailed Regulations", with low construction cost and high work efficiency. The comprehensive construction cost lowers 40%~50% in comparison with back suspending net system.%在国内首次开发了高层住宅现浇混凝土外墙无网浇合外保温体系。该体系采用无钢丝网架的聚苯板为保温板,抗裂层由聚合物水泥砂浆及耐碱玻纤网格布组成,再用塑料胀管锚固。经聚苯板与混凝土粘合力、塑料胀管抗拔力、压缩率及抗冻试验表明该体系性能可靠、安全度高;热工测试表明满足北京市《节能细则》对墙体节能50%的要求;造价低、工效高,综合造价比后挂有网体系降低40%~50%。

  17. Wave Run-up on A Coaxial Perforated Circular Cylinder

    Institute of Scientific and Technical Information of China (English)

    ZHU Da-tong

    2011-01-01

    This paper describes a plane regular wave interaction with a combined cylinder which consists of a solid inner column and a coaxial perforated outer cylinder. The outer perforated surface is a thin porous cylinder with an annular gap between it and the inner cylinder. The non-linear boundary condition at the perforated wall is a prime focus in the study;energy dissipation at the perforated wall occurs through the resistance to the fluid across the perforated wall. Explicit analytical formulae are presented to calculate the wave run-up on the outer and inner surfaces of the perforated cylinderand the surface of the inner column. The theoretical results of the wave run-up are compared with previous experimental data. Numerical results have also been obtained: when the ratio of the annular gap between the two cylinders to incidentwavelength (b-a)/L≤0.1, the wave run-up on the inner surface of the perforated cylinder and the surface of inner column can partially or completely exceed the incident wave height.

  18. Methods for the evaluation of thermal insulation systems and heat bridges of multi-leaf external walls and measures for the reduction of transmission heat losses of facades. Verfahren zur Beurteilung des Waermeschutzes und der Waermebruecken von mehrschaligen Aussenwaenden und Massnahmen zur Verminderung der Transmissionswaermeverluste von Fassaden

    Energy Technology Data Exchange (ETDEWEB)

    Achtziger, J.

    1989-08-01

    When calculating the heat transition coefficient of multi-leaf external walls it shows that particular in case of lightweight metal facades and external walls with coverings the simplified method leads to a too favourable assessment of the building unit and that improvements of the thermal insulation do not have the effect desired. On the basis of exact experimental and arithmetical investigation methods the order of magnitude of the differences from thermal insulation have been found out and also to what extent these can be neglected or have correspondingly to be taken into account. Starting from these results functional influences have been deduced for the different wall constructions. Among the external wall systems investigated were metal constructions and windows, profiled sheet walls and multi-leaf walls of brickwork and of concrete shell as well as wood skeleton and wood panel constructions. The results of these are presented, comparisons are drawn, factors are named which influence the heat transition, the thermal insulation is judged and constructive suggestions for improvements are made. (HWJ).

  19. Poiseuille flow-induced vibrations of two cylinders in tandem

    Science.gov (United States)

    Lin, Jianzhong; Jiang, Renjie; Chen, Zhongli; Ku, Xiaoke

    2013-07-01

    Laminar flows past two tandem cylinders which are free to move transversely in a parallel-wall channel were studied numerically by the lattice Boltzmann method. With fixed Reynolds number Re=100, blockage ratio β=1/4 and structural damping ξ=0, the effect of streamwise separation between two cylinders at a range of S/D=[1.1, 10] on the motions of cylinders and fluids was studied for both mass ratios of m(*)=1 and m(*)=0.1. A variety of distinct vibration regimes involving periodic, quasi-periodic and non-periodic vibrations with corresponding flow patterns were observed. A detailed analysis of the vibration amplitudes, vibration frequencies and relative equilibrium positions for both mass ratios demonstrated that as S/D increases, the interaction of the two cylinders first enhances and then reduces. In the strong coupling regime, both cylinders oscillate periodically around the centerline of the channel with large vibration amplitudes and high vibration frequencies. By comparing with the case of an isolated cylinder, a further study indicated that the gap flow plays an important role in such a dynamic system, and the vortex cores formation behind the front cylinder causes the interaction of the cylinders decouple rapidly. Based on the present observations, such a dynamic model system can be considered as a novel type of vortex-induced vibrations (VIV) and is expected to find applications in fluid mixing and heat transfer.

  20. Prediction of External Corrosion for Steel Cylinders 2003 Report

    Energy Technology Data Exchange (ETDEWEB)

    Schmoyer, RLS

    2003-09-24

    Depleted uranium hexafluoride (UF{sub 6}) is stored in over 60,000 steel cylinders at the East Tennessee Technology Park (ETTP) in Oak Ridge, Tennessee, at the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and at the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The cylinders range in age from six to 52 years. Although when new the cylinders had wall thicknesses specified to within manufacturing tolerances, over the years corrosion has reduced their actual wall thicknesses. The UF{sub 6} Cylinder Project is managed by the United States Department of Energy (DOE) to safely maintain the UF{sub 6} and the cylinders containing it. The requirements of the Project are delineated in the System Requirements Document (LMES 1997a), and the actions needed to fulfill those requirements are specified in the System Engineering Management Plan (LMES 1997b). This report documents activities that address requirements and actions involving forecasting cylinder wall thicknesses. Wall thickness forecasts are based on models fit to ultrasonic thickness (UT) measurement data. First, UT data collected during FY02 is combined with UT data collected in earlier years (FY92-FY01), and all of the data is inventoried chronologically and by various subpopulations. Next, the data is used to model either maximum pit depth or minimum thickness as a function of cylinder age, subpopulation (e.g., PGDP G-yard, bottom-row cylinders), and initial thickness estimates. The fitted models are then used to extrapolate minimum thickness estimates into the future and to compute estimates of numbers of cylinders expected to fail various thickness criteria. A model evaluation is performed comparing UT measurements made in FY02 with model-fitted projections based only on data collected before FY02. The FY02 UT data, entered into the corrosion model database and not available for the previous edition of this report (Schmoyer and Lyon 2002), consists of thickness measurements of 48

  1. 预制夹芯保温墙体板缝抗火性能试验研究%Experimental research on fire-resistance behavior of precast sandwich insulation wall panel joints

    Institute of Scientific and Technical Information of China (English)

    李志杰; 秦桁; 刘国权; 薛伟辰

    2012-01-01

    According to the test methods of the national standard Plastics—Determination of burning characteristics—Horizontal and vertical test(GB/T 2408—2008),experimental research on fire-resistance behavior for three kinds of wall panel joints about the precast sandwich insulation wall panels(including no filler material wall panel joint,filling PE foam wall panel joint and filling rock wool wall panel joint) were done using the Bunsen burner.The results indicate that when no filler material wall panel joint was fired 30 minutes(the maximum flame temperature is 957℃),the highest temperature of FRP connector is 132℃ in internal wall panel and 97℃ in the external wall panel,respectively.It exceeds the glass transition temperature 93℃ of the FRP material.The XPS material burnt strongly and melting at this moment.It proves that fire-resistance behavior of no filler material wall panel joint is poorer,and can not satisfy the requirement of fire safety.After fired 60 minutes,the highest flame temperature is about 970℃.The FRP connectors are remain intact for filling PE foam wall panel joint and filling rock wool wall panel joint.The highest temperature of filling PE foam wall panel joint is 78℃ in the internal wall panel and 42℃ in the external wall panel,respectively.The highest temperature of filling rock wool wall panel joint is 47℃ in the internal wall panel and 36℃ in the external wall panel,respectively.The XPS material for the two kinds of wall panel joints does not produce flame or drop things at this moment.It shows that wall panel joints filled with PE foam or filled with rock wool have good fire-resistance behavior,and are applicable in the practical projects.%按照国家标准《塑料燃烧性能的测定水平法和垂直法》(GB/T 2408—2008)的有关试验方法,采用本生灯对预制夹芯保温墙体的3种板缝构造(无填充材料、填充PE棒泡沫条以及填充岩棉条)的抗火性能进行了试验研究。研究

  2. Controllable Hysteresis and Threshold Voltage of Single-Walled Carbon Nano-tube Transistors with Ferroelectric Polymer Top-Gate Insulators

    Science.gov (United States)

    Sun, Yi-Lin; Xie, Dan; Xu, Jian-Long; Zhang, Cheng; Dai, Rui-Xuan; Li, Xian; Meng, Xiang-Jian; Zhu, Hong-Wei

    2016-03-01

    Double-gated field effect transistors have been fabricated using the SWCNT networks as channel layer and the organic ferroelectric P(VDF-TrFE) film spin-coated as top gate insulators. Standard photolithography process has been adopted to achieve the patterning of organic P(VDF-TrFE) films and top-gate electrodes, which is compatible with conventional CMOS process technology. An effective way for modulating the threshold voltage in the channel of P(VDF-TrFE) top-gate transistors under polarization has been reported. The introduction of functional P(VDF-TrFE) gate dielectric also provides us an alternative method to suppress the initial hysteresis of SWCNT networks and obtain a controllable ferroelectric hysteresis behavior. Applied bottom gate voltage has been found to be another effective way to highly control the threshold voltage of the networked SWCNTs based FETs by electrostatic doping effect.

  3. Rolling Cylinder Phase 1

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Taraborrelli, Valeria Taraborrelli

    Margheritini and Valeria Taraborrelli(valeria.taraborrelli@hotmail.it) with a total of 3 day visit from the developers. Laboratory tests in irregular waves will be performed by Lucia Margheritini. The report is aimed at the first stage testing of the Rolling Cylinder wave energy device. This phase includes...

  4. High-R Walls for Remodeling: Wall Cavity Moisture Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Wiehagen, J.; Kochkin, V.

    2012-12-01

    The focus of the study is on the performance of wall systems, and in particular, the moisture characteristics inside the wall cavity and in the wood sheathing. Furthermore, while this research will initially address new home construction, the goal is to address potential moisture issues in wall cavities of existing homes when insulation and air sealing improvements are made.

  5. High-R Walls for Remodeling. Wall Cavity Moisture Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Wiehagen, J. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Kochkin, V. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States)

    2012-12-01

    The focus of the study is on the performance of wall systems, and in particular, the moisture characteristics inside the wall cavity and in the wood sheathing. Furthermore, while this research will initially address new home construction, the goal is to address potential moisture issues in wall cavities of existing homes when insulation and air sealing improvements are made.

  6. Development of High Performance Composite Foam Insulation with Vacuum Insulation Cores

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Kaushik [ORNL; Desjarlais, Andre Omer [ORNL; SmithPhD, Douglas [NanoPore, Inc.; LettsPhD, John [Firestone Building Products; YaoPhD, Jennifer [Firestone Building Products

    2016-01-01

    Development of a high performance thermal insulation (thermal resistance or R-value per inch of R-12 hr-ft2- F/Btu-in or greater), with twice the thermal resistance of state-of-the-art commercial insulation materials ( R6/inch for foam insulation), promises a transformational impact in the area of building insulation. In 2010, in the US, the building envelope-related primary energy consumption was 15.6 quads, of which 5.75 quads were due to opaque wall and roof sections; the total US consumption (building, industrial and transportation) was 98 quads. In other words, the wall and roof contribution was almost 6% of the entire US primary energy consumption. Building energy modeling analyses have shown that adding insulation to increase the R-value of the external walls of residential buildings by R10-20 (hr-ft2- F/Btu) can yield savings of 38-50% in wall-generated heating and cooling loads. Adding R20 will require substantial thicknesses of current commercial insulation materials, often requiring significant (and sometimes cost-prohibitive) alterations to existing buildings. This article describes the development of a next-generation composite insulation with a target thermal resistance of R25 for a 2 inch thick board (R12/inch or higher). The composite insulation will contain vacuum insulation cores, which are nominally R35-40/inch, encapsulated in polyisocyanurate foam. A recently-developed variant of vacuum insulation, called modified atmosphere insulation (MAI), was used in this research. Some background information on the thermal performance and distinguishing features of MAI has been provided. Technical details of the composite insulation development and manufacturing as well as laboratory evaluation of prototype insulation boards are presented.

  7. THE EXPERIMENT WITH FARADAY CYLINDER

    Institute of Scientific and Technical Information of China (English)

    薛英

    2004-01-01

    Suppose there are two electricity testers, A and B(Figure A) . And a metal cylinder C which is almost closed (called Faraday Cylinder)is fixed to tester B, making both tester B and cylinder C charged. As a result, the aluminium foil on tester B opens.

  8. Measure Guideline: Hybrid Foundation Insulation Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K.; Lstiburek, J.

    2012-05-01

    This measure guideline provides recommendations for designs and variations for retrofit hybrid assemblies in improving interior foundation insulation and water management of basements. Variations include closed cell spray foam (ccSPF) with membrane waterproofing or air gap membrane drainage layers, rigid board foam insulation at flat walls (cast concrete or CMU block), a 'partial drainage' detail making use of the bulk water drainage that occurs through the field of a rubble stone wall, and non-drained spray foam assemblies (including slab insulation).

  9. Measure Guideline. Hybrid Foundation Insulation Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

    2012-05-01

    This measure guideline provides recommendations for designs and variations for retrofit hybrid assemblies in improving interior foundation insulation and water management of basements. Variations include closed cell spray foam (ccSPF) with membrane waterproofing or air gap membrane drainage layers, rigid board foam insulation at flat walls (cast concrete or CMU block), a “partial drainage” detail making use of the bulk water drainage that occurs through the field of a rubble stone wall, and non-drained spray foam assemblies (including slab insulation).

  10. Wool insulation

    Energy Technology Data Exchange (ETDEWEB)

    O`Shea, Angus

    1995-05-01

    Wool insulation usually comes in two forms, as loose fill or batts. The reliability of loose fill as an insulator, the thickness of batts and the wool`s vulnerability to insect and moth attack are considered to be problems. The purpose of this research was to create a commercial wool insulation product to overcome these limitations, at the same time withstanding the Australian and international standards for fire resistance. The project also considered the market potential of such a product with a view to commercialization. The loft or thickness problem was resolved by covering the wool with an oven baked adhesive. A fire retardant and anti-insect treatment was incorporated into the spray process to produce a viable product.

  11. Dropwise Condensation on Hydrophobic Cylinders

    CERN Document Server

    Park, Kyoo-Chul; Hoang, Michelle; McManus, Brendan; Aizenberg, Joanna

    2016-01-01

    In this work, we studied the effect of the diameter of horizontal hydrophobic cylinders on droplet growth. We postulate that the concentration gradient created by natural convection around a horizontal circular cylinder is related to the droplet growth on the cylinder by condensation. We derive a simple scaling law of droplet growth and compare it with experimental results. The predicted negative exponent of drop diameter (d) as a function of cylinder diameter (D) at different time points is similar to the general trend of experimental data. Further, this effect of cylinder diameter on droplet growth is observed to be stronger than the supersaturation conditions created by different surface temperatures.

  12. Gain control for solar wall heating with transparent insulation (TI) - requirements for cost effective application of natural ventilation in multifunctional and ventilated facades (MFVF)

    Energy Technology Data Exchange (ETDEWEB)

    Haller, A.; Althaus, H.J. [Ernst Schweizer AG, Hedingen (Switzerland); Platzer, W.J. [Fraunhofer Inst. for Solar Energy Systems, ISE, Freiburg (Germany); Goerdt, W. [PSE Projektgesellschaft Solare Energiesysteme mbH, Freiburg (Germany)

    2000-07-01

    This paper describes the potential of natural ventilation for solar wall heating systems with TI in order to avoid overheating in summer. Based on a commercial facade system two prototypes have been built with different absorber characteristics. The measurements on a outdoor test site showed that it is possible to reach an equivalent energy transmission value (g-value) as low as 15% in ventilated mode. In heating mode with sealed ventilation cavity the g-value reaches 48%. With a lime stone mass wall this yields to a system efficiency of 36% and an U-value below 1 W/m{sup 2}K. The variation of the absorber characteristics showed that is possible to reach higher solar gains in winter at the cost of higher g-values in summer. The optimum depends on the application and its tolerance to summer heat gains. The experiments did also confirm the demanding requirements for the ventilation valve construction in closed state: 140 deg. C maximum operating temperature, U-value of 1 W/m{sup 2}K, air tightness comparable to a low energy window. In ventilation state, a open area of 600 dm{sup 2} per meter width with low pressure drop is required. Unfortunately no systems or products are commercially available to fulfil these requirements. Thus, three concepts were further investigated for this application. Test showed that there will be more development and investment required for a commercial facade product. (au)

  13. Topological insulators

    CERN Document Server

    Franz, Marcel

    2013-01-01

    Topological Insulators, volume six in the Contemporary Concepts of Condensed Matter Series, describes the recent revolution in condensed matter physics that occurred in our understanding of crystalline solids. The book chronicles the work done worldwide that led to these discoveries and provides the reader with a comprehensive overview of the field. Starting in 2004, theorists began to explore the effect of topology on the physics of band insulators, a field previously considered well understood. However, the inclusion of topology brings key new elements into this old field. Whereas it was

  14. Thermophysical investigations of nanotechnological insulation materials

    Science.gov (United States)

    Lakatos, Ákos

    2017-07-01

    Nowadays, to sufficiently reduce the heat loss through the wall structures with the so-called traditional insulations (polystyrene and fibrous slabs), huge thicknesses (20 - 25 cm) must be applied. In some cases there is no place for their applications e.g.: historical or heritage builfings, since the use of nano-insulation materials (aerogel, vacuum ceramic paints) takes place. They are said to be much more efficient insulations than the above mentioned ones, since they should be used in thinner forms. In this article the thermal insulating capability of solid brick wall covered with a silica-aerogel slab with 1.3 cm, moreover with a vacuum ceramic hollow contained paint with 2 mm thick are investigated. As well as a literature review about the thermal conductivity of nano-technological insulation materials will be given. Comparison of the atomic and thermal diffusion will be also presented.

  15. Instability of Taylor-Couette Flow between Concentric Rotating Cylinders

    CERN Document Server

    Dou, H S; Phan-Thien, N; Yeo, K S; Dou, Hua-Shu; Khoo, Boo Cheong; Phan-Thien, Nhan; Yeo, Koon Seng

    2005-01-01

    The energy gradient theory is used to study the instability of Taylor-Couette flow between concentric rotating cylinders. In our previous studies, the energy gradient theory was demonstrated to be applicable for wall bounded parallel flows. It was found that the critical value of the energy gradient parameter K at subcritical transition is about 370-389 for wall bounded parallel flows (which include plane Poiseuille flow, pipe Poiseuille flow and plane Couette flow) below which no turbulence occurs. In this paper, the detailed derivation for the calculation of the energy gradient parameter in the flow between concentric rotating cylinders is provided. The theoretical results for the critical condition of primary instability obtained are in very good agreement with the experiments found in literature. The mechanism of spiral vortices generation for counter-rotating of two cylinders is also explained using the energy gradient theory. The energy gradient theory can also serve to relate the condition of flow tran...

  16. Machining Thin-Walled Cylindrical Parts

    Science.gov (United States)

    Cimbak, Joe; Spagnolo, Jim; Kraus, Dan

    1988-01-01

    Cylindrical walls only few thousandths of inch thick machined accurately and without tears or punctures with aid of beryllium copper mandrel. Chilled so it contracts, then inserted in cylinder. As comes to room temperature, mandrel expands and fits snugly inside cylinder. Will not allow part to slide and provides solid backup to prevent deflection when part machined by grinding wheel. When machining finished, cylinder-and-mandrel assembly inserted in dry ice, mandrel contracts and removed from part.

  17. Translucent Insulation

    DEFF Research Database (Denmark)

    Rahbek, Jens Eg

    1998-01-01

    Two new types of translucent materials are presented. One is translucent fiber insulation and the other type is a new type of hony-comb made of Celulose-acetat. Data for the materials and calculations of energy savings when using the materials in building envelopes are presented....

  18. A Short Study of Large Rotary Forged Cylinders

    Science.gov (United States)

    1979-06-01

    Bottom) 7 Microstructure at mid-wall of reheat treated rotary 25 forged cylinders - Martensite- Bainite 8 Martensitic microstructure of (a) normalized...also was unsatisfactory (Table 2). The microstructure at the mid-wall of both the top and bottom showed evidence of ferrite and bainite (Figs. 1 and...austenitized, and of bainite , showing that the material transformed to austenite had been in- adequately quenched, since martensite is the desired product

  19. Prediction of External Corrosion for Steel Cylinders--2002 Report

    Energy Technology Data Exchange (ETDEWEB)

    Schmoyer, RLS

    2002-07-31

    The United States Department of Energy (DOE) manages the UF{sub 6} Cylinder Project. The project was formed to maintain and safely manage the depleted uranium hexafluoride (UF{sub 6}) stored in approximately 50,000 carbon steel cylinders. The cylinders are located at three DOE sites: the East Tennessee Technology Park (ETTP) site in Oak Ridge, Tennessee; the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The System Requirements Document (SRD) (LMES 1997a) delineates the requirements of the project, and the actions needed to fulfill these requirements are specified in the System Engineering Management Plan (SEMP) (LMES 1997b). This report documents activities that in whole or part satisfy specific requirements and actions stated in the UF{sub 6} Cylinder Project SRD and SEMP with respect to forecasting cylinder conditions. The results presented here supercede those presented by Lyon (1995, 1996, 1997, 1998, 2000), and Schmoyer and Lyon (2001). Many of the wall thickness projections made in this report are conservative, because they are based on the assumption that corrosion trends will continue, despite activities such as improved monitoring, relocations to better storage, painting, and other improvements in storage conditions relative to the conditions at the times most of the wall thickness measurements were made. For thin-wall cylinders (design nominal wall thickness 312.5 mils), the critical minimum wall thicknesses criteria used in this report are 0 (breach), 62.5 mils, and 250 mils (1 mil = 0.001 in.). For thick-wall cylinders (design nominal wall thickness 625 mils), the thickness criteria used in this report are 0, 62.5 mils, and 500 mils. The criteria triples are preliminary boundaries identified within the project that indicate (1) loss of material (UF{sub 6}), (2) safe handling and stacking operations, and (3) standards for off-site transport and contents transfer

  20. Alternative method of retesting UF{sub 6} cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Christ, R. [Nuclear Crago + Service GmbH, Hanau (Germany)

    1991-12-31

    The paper describes an alternative method to perform the periodic inspection of UF{sub 6} cylinders. The hydraulic test is replaced by ultrasonic checking of wall thickness and by magnetic particle testing of all the weld seams. Information about the legal background, the air leak test and the qualification of inspectors is also given.

  1. 浅谈绿色建筑材料在墙体保温工程中的应用%Application of Green Building Materials in Wall Insulation Project

    Institute of Scientific and Technical Information of China (English)

    贾涛; 苗方利

    2014-01-01

    The production and business model of housing industry save time and labor, reduce costs, save contraction period. Building materials and products are the basic material elements of housing construction. Housing industry puts forward new demands for new materials and new products from the specification, quality and performance. This paper will research the application of green building materials in wall insulation project.%住宅产业化的生产和经营模式省工省时、降低成本、节约工期。建材和制品是住宅建设基本的物质要素。住宅产业化对新建材和新制品从规格、质量、性能上都将提出新的要求。本文将研究绿色建筑材料在墙体保温工程中的应用。

  2. Thermal Performance Analysis on Insulation Wall Made of Composite Ceramic Concrete Block%复合陶粒混凝土砌块自保温墙体的热工性能分析

    Institute of Scientific and Technical Information of China (English)

    曾理; 孙林柱

    2011-01-01

    以温州大学E区二期学生公寓为试点工程,采用复合陶粒混凝土砌块为主要建筑材料,对自保温外墙的围护结构进行了节能设计。对试点工程热工性能进行了现场测试,并对测试数据进行了分析评价,结果表明:依据DB33/1015—2003浙江省《居住建筑节能设计标准》的规定,该试点工程可达到建筑节能50%的设计要求。%Taking student apartments (the second period of E area) in Wenzhou University as a pilot project, designed an energy efficient envelope structure for self-insulation wall made of composite ceramic concrete block. Conducted on-site tests on its thermal performance and made an analysis and evaluation on the tested data. The results show that: According to DB3311015--2003 " Design standards for energy efficiency of residential buildings" of Zhejiang province, the project has reached the design requirement of 50% energy saving.

  3. Experiment and Design of Steel Thin Wall Cylinder Liner of Ultrasonic Honing and Its Research%超声珩磨钢质薄壁缸套的试验设计研究

    Institute of Scientific and Technical Information of China (English)

    乔培平

    2015-01-01

    This paper uses longitudinal vertical ultrasonic vibration honing device, respectively in MB4215Z type semi-automatic ho-ning machine and M4215 type honing machine to do three factors and four levels orthogonal test for steel thin wal cylinder liner and studies the characteristics of the ultrasonic honing oilstone, including super hard abrasive, grain size and binder on the surface roughness, dimensional accuracy, roundness, and the influence on honing efficiency. Results show that ultrasonic honing can be used to effectively solve the steel thin wal cylinder honing processing problems and a theoretical basis is provided for honing pro-cessing mild steel. This gives a certain guiding role to the actual production.%采用纵向振动立式超声珩磨装置,分别在MB4215Z型半自动珩磨机和M4215型珩磨机上,对钢制薄壁缸套基体进行三因素、四水平正交试验,研究了超声珩磨油石的特性,包括超硬磨料、粒度、结合剂等对表面粗糙度、尺寸精度、圆度和珩磨效率等的影响及影响程度。结果表明,超声珩磨可以有效地解决钢制薄壁缸套的珩磨加工难题,为珩磨加工软钢提供了理论依据,对实际生产具有一定的指导作用。

  4. Sedimentation of a Single Charged Elliptic Cylinder in a Newtonian Fluid by Lattice Boltzmann Method

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chao-Ying; SHI Juan; TAN Hui-Li; LIU Mu-Ren; KONG Ling-Jiang

    2004-01-01

    @@ We simulate the sedimentation of single charged and single uncharged elliptic cylinders in a Newtonian fluid by using the lattice Boltzmann method. Due to the polarizing effects and non-axial symmetry shape, there are the Coulomb force and corresponding torque exerted on the charged elliptic cylinder during the sedimentation, which significantly change the horizontal translation and rotation of the cylinder. When the dielectric constant of the liquid is smaller than that of the wall, the direction of the Coulomb force is opposite to that of the hydrodynamic force. Therefore there appears to be a critical linear charge density qc at which the elliptic cylinder will fall vertically off the centreline.

  5. High Performance Slab-on-Grade Foundation Insulation Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Louise F. [NorthernSTAR, St. Paul, MN (United States); Mosiman, Garrett E. [NorthernSTAR, St. Paul, MN (United States)

    2015-09-01

    ?A more accurate assessment of SOG foundation insulation energy savings than traditionally possible is now feasible. This has been enabled by advances in whole building energy simulation with 3-dimensional foundation modelling integration at each time step together with an experimental measurement of the site energy savings of SOG foundation insulation. Ten SOG insulation strategies were evaluated on a test building to identify an optimum retrofit insulation strategy in a zone 6 climate (Minneapolis, MN). The optimum insulation strategy in terms of energy savings and cost effectiveness consisted of two components: (a) R-20 XPS insulation above grade, and, (b) R-20 insulation at grade (comprising an outer layer of R-10 insulation and an interior layer of R-12 poured polyurethane insulation) tapering to R-10 XPS insulation at half the below-grade wall height (the lower half of the stem wall was uninsulated). The optimum insulation strategy was applied to single and multi-family residential buildings in climate zone 4 - 7. The highest site energy savings of 5% was realized for a single family home in Duluth, MN, and the lowest savings of 1.4 % for a 4-unit townhouse in Richmond, VA. SOG foundation insulation retrofit simple paybacks ranged from 18 to 47 years. There are other benefits of SOG foundation insulation resulting from the increase in the slab surface temperatures. These include increased occupant thermal comfort, and a decrease in slab surface condensation particularly around the slab perimeter.

  6. Moisture Conditions in Passive House Wall Constructions

    OpenAIRE

    Gullbrekken, Lars; Geving, Stig; Time, Berit; ANDRESEN, Inger

    2015-01-01

    Buildings for the future, i.e zero emission buildings and passive houses, will need well insulated building envelopes, which includes increased insulation thicknesses for roof, wall and floor constructions. Increased insulation thicknesses may cause an increase in moisture levels and thereby increased risk of mold growth. There is need for increased knowledge about moisture levels in wood constructions of well insulated houses, to ensure robust and moisture safe solutions. Monitoring of w...

  7. A PORTABLE DENTAL STERILIZING CYLINDER

    Science.gov (United States)

    The report describes an aluminum cylinder in which dental instruments could be sterilized under emergency field conditions and at the same time be...protected against corrosion. The procedure involves loading the cylinder with dental instruments, flushing it with ethylene oxide-Freon gas, closing it...and then immersing it in boiling water for l hour. In preliminary experiments with a prototype of the sterilizing cylinder, dental instruments were

  8. Mixed convection of ferrofluids in a lid driven cavity with two rotating cylinders

    Directory of Open Access Journals (Sweden)

    Fatih Selimefendigil

    2015-09-01

    Full Text Available Mixed convection of ferrofluid filled lid driven cavity in the presence of two rotating cylinders were numerically investigated by using the finite element method. The cavity is heated from below, cooled from driven wall and rotating cylinder surfaces and side vertical walls of the cavity are assumed to be adiabatic. A magnetic dipole source is placed below the bottom wall of the cavity. The study is performed for various values of Reynolds numbers (100 ≤ Re ≤ 1000, angular rotational speed of the cylinders (−400 ≤ Ω ≤ 400, magnetic dipole strengths (0 ≤ γ ≤ 500, angular velocity ratios of the cylinders (0.25≤Ωi/Ωj≤4 and diameter ratios of the cylinders (0.5≤Di/Dj≤2. It is observed that flow patterns and thermal transport within the cavity are affected by variation in Reynolds number and magnetic dipole strength. The results of this investigation revealed that cylinder angular velocities, ratio of the angular velocities and diameter ratios have profound effect on heat transfer enhancement within the cavity. Averaged heat transfer enhancements of 181.5 % is achieved for clockwise rotation of the cylinder at Ω = −400 compared to motionless cylinder case. Increasing the angular velocity ratio from Ω2/Ω1=0.25 to Ω2/Ω1=4 brings about 91.7 % of heat transfer enhancement.

  9. 石灰-水泥系外墙防水装饰砂浆与外墙外保温系统适应性研究%The adaptive research of lime-cement waterproof decorative mortar for exterior wall and exterior insulation system

    Institute of Scientific and Technical Information of China (English)

    韩方晖; 王栋民; 许晨阳; 刘晓斌; 刘天德

    2012-01-01

    To make lime-cement waterproof decorative mortar for exterior wall which successes through chemical modification technology to be widely applied in exterior insulation system, it must have good adaptability with exterior insulation system. This paper through establishing force diagram of facing external wall thermal insulation and adopting ESP external wall thermal insulation to be used in high-rise building)analyzing and calculating the earthquake effect by level, wind load and both combination effect and vertical stress gravity and bond force: meanwhile,on the basis of the calculation method to calculate the force of the 100 m-high high-rise building top exterior insulation system in the Beijing center: furthermore, calculating the force of facing external wall thermal insulation when the exterior wall facing is ceramic tile, coating and carrying on the comparison. Results indicate: it is safe when the exterior wall facing is lime-cement waterproof decorative mortar for exterior wall in high-rise exterior insulation system; by the size of the load is for ceramic tile > lime-cement waterproof decorative mortar for exterior wall > coating, in comprehensive comparison, lime-cement waterproof decorative mortar for exterior wall has superiority.%要使通过化学改性技术研制成功的石灰-水泥系外墙防水装饰砂浆在外墙外保温系统中得到广泛应用,其必须与外墙外保温系统有很好的适应性.通过建立饰面外墙外保温系统受力图,对采用膨胀聚苯板作为高层建筑外墙外保温时,所受水平地震作用、风荷载和两者组合效应及竖直方向受力重力和压剪粘结力分析计算;同时,依据这些计算方法计算了北京市中心高为100m的高层建筑顶部外墙外保温系统受力情况;计算了外墙饰面为瓷砖、涂料时外墙外保温系统的受力情况,并对其进行比较.结果表明:外墙饰面为石灰-水泥系外墙防水装饰砂浆时应用于高层外

  10. Hollow system with fin. Transient Green function method combination for two hollow cylinders

    Directory of Open Access Journals (Sweden)

    Buikis Andris

    2017-01-01

    Full Text Available In this paper we develop mathematical model for three dimensional heat equation for the system with hollow wall and fin and construct its analytical solution for two hollow cylindrical sample. The method of solution is based on Green function method for one hollow cylinder. On the conjugation conditions between both hollow cylinders we construct solution for system wall with fin. As result we come to integral equation on the surface between both hollow cylinders. Solution is obtained in the form of second kind Fredholm integral equation. The generalizing of Green function method allows us to use Green function method for regular non-canonical domains.

  11. Poiseuille flow past a nanoscale cylinder in a slit channel: Lubrication theory versus molecular dynamics analysis

    CERN Document Server

    Rahmani, Amir M; Jupiterwala, Mehlam; Colosqui, Carlos E

    2015-01-01

    Plane Poiseuille flow past a nanoscale cylinder that is arbitrarily confined (i.e., symmetrically or asymmetrically confined) in a slit channel is studied via hydrodynamic lubrication theory and molecular dynamics simulations, considering cases where the cylinder remains static or undergoes thermal motion. Lubrication theory predictions for the drag force and volumetric flow rate are in close agreement with molecular dynamics simulations of flows having molecularly thin lubrication gaps, despite the presence of significant structural forces induced by the crystalline structure of the modeled solid. While the maximum drag force is observed in symmetric confinement, i.e., when the cylinder is equidistant from both channel walls, the drag decays significantly as the cylinder moves away from the channel centerline and approaches a wall. Hence, significant reductions in the mean drag force on the cylinder and hydraulic resistance of the channel can be observed when thermal motion induces random off-center displace...

  12. 发泡水泥对日光温室黏土砖墙保温蓄热性能的改善效果%Improving effect of heat insulation performance of brick wall thickened with foam cement in solar greenhouse

    Institute of Scientific and Technical Information of China (English)

    李明; 魏晓明; 周长吉; 郑禾; 李小明

    2014-01-01

    The wall of a Chinese solar greenhouse can absorb heat during daytime and supply heat into the greenhouse during nighttime. It can help the solar greenhouse to maintain high indoor air temperature during winter nighttime with little or no supplemental heating. The brick wall is one of the popular walls. However, after a long period of use, walls have the bad performance on heat insulation and sealing. To solve the problems, we proposed to thicken the brick wall with foam cement to decrease its heat loss and keep the heat in the wall as much as possible. Then, the stored heat that the wall can supply during the nighttime can be increased. In this study, a solar greenhouse with the brick wall, which was composed of 120 mm thick brick, 100 mm thick polystyrene board, and 240 mm thick brick (from indoor to outdoor), was used as the control greenhouse. The test greenhouse had same structure and management with the control greenhouse, but its brick wall was thickened with 200 mm thick foam cement on the outdoor side. This wall was defined as the transformed wall. The heat insulation and supply performances of the two solar greenhouses’ walls were compared based on the data collected in a typical sunny day and a cloudy day. As for the heat insulation performance, the outdoor surface temperatures of the brick wall and the transformed wall were (2.8±0.9) and (0.8±0.2)℃ higher than the outdoor air temperature, respectively, in the nighttime of the sunny day. The maximum heat flux in the foam cement was about 9%of that on the outdoor surface of the brick wall. A similar phenomenon was also observed in the nighttime of the cloudy day. The results indicated that thickening the brick wall with foam cement could decrease the heat loss of the wall and keep more heat in the wall. As for the heat supply performance, the indoor surface temperatures of the brick wall and the transformed wall were (1.5±0.5) and (2.4±0.2)℃higher than the outdoor air temperature, respectively

  13. Supercritical flows past a square cylinder with rounded corners

    Science.gov (United States)

    Cao, Yong; Tamura, Tetsuro

    2017-08-01

    Large-eddy simulations were used to investigate the supercritical aerodynamics of a square cylinder with rounded corners in comparison with those in the subcritical regime. First, the numerical methods, especially the dynamic mixed model, were validated on the basis of their prediction of supercritical flows past a circular cylinder. Then, the supercritical flows past a rounded-corner square cylinder were simulated and systematically clarified. Strong Reynolds number (Re) effects existed in the forces and local pressures as Re increased from o(104) to o(106). Changeover of flow patterns occurred as Re increased. At the supercritical Re, the free stream overall flowed along the cross sections of the cylinder, separated from the leeward corners and generated Karman vortices behind the cylinder. This pattern resulted in a much smaller recirculation region behind the cylinder compared with the subcritical flow. At the micro level, the flow experienced laminar separation and flow reattachment near the frontal corners, followed by the spatial development of turbulent boundary layers (TBLs) on the side faces and turbulent separation near the leeward corners. The feedback by large-scale primary vortex shedding and the small-scale turbulent motions in the high-frequency region with a slope of -5/3 were detected in the TBL. Their interaction affected the spanwise correlations of wall pressure fluctuations. The TBL on the side face differed from the zero-pressure-gradient flat-plate one; it was subjected to pressure gradients varying in space and time.

  14. The impact of added insulation on air leakage

    Energy Technology Data Exchange (ETDEWEB)

    Anon

    2002-01-01

    It is relatively easy to calculate the impact on energy consumption when thermal insulation is added to the building envelope. However, other effects such as air leakage through the exterior wall assembly, and the potential for water condensation also have to be considered. By adding insulation to the exterior wall assembly, the temperature gradient of the wall is changed and the risk of condensation is increased, especially if warm, moist indoor air can flow through the wall. The study by Dominique Derome, Paul Fazio and Guylaine Desmarais for the CMHC Research Division, of which this paper is a summary, examined three types of air leakage paths, i.e. long air exfiltration path; concentrated air exfiltration path; and distributed exfiltration path. Experiments involved placing 38 mm rigid extruded polystyrene insulation on the interior side of three wood studs and fiberglass batt insulation wall assemblies, while four other samples had the same 38 mm rigid extruded polystyrene insulation added on the exterior of the assembly over the fiberboard sheathing. Both, warm and cold side additions of rigid foam insulation to the existing assemblies increased thermal performance by 55 per cent. When blown cellulose fibre was used as insulation instead of fibreglass batting, the increase in thermal performance was 66 per cent. Addition of the rigid foam insulation on the warm side tended to increase the effectiveness. For example, moisture content generally did not rise above 25 per cent, whereas it could climb up to 70 per cent when the insulation was added on the cold side.

  15. Relevant surgical anatomy of the chest wall

    OpenAIRE

    Rajesh, Pala Babu; Naidu, Babu V.

    2010-01-01

    The chest wall, like other regional anatomy, is a remarkable fusion of form and function. Principal functions are the protection of internal viscera and an expandable cylinder facilitating variable gas flow into the lungs. Knowledge of the anatomy of the whole cylinder (ribs, sternum, vertebra, diaphragm, intercostal spaces, and extrathoracic muscles) is therefore not only important in the local environment of a specific chest wall resection but also in its relation to overall function. An un...

  16. Discussion on the Heat Insulation Technology of Rigid Polyurethane Foam External Wall%聚氨酯硬泡外墙隔热保温技术的探讨

    Institute of Scientific and Technical Information of China (English)

    董飞翔

    2014-01-01

    目前,聚氨酯硬泡外墙隔热保温技术是一种主要应用的保温技术。本文重点对聚氨酯硬泡外墙隔热保温技术进行了探讨。%At present, the polyurethane rigid foam exterior wal insulation technology is a major thermal insulation tech- nology. This paper focuses on the rigid polyurethane foam wal insulation technology.

  17. An experiment in heat conduction using hollow cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Ortuno, M; Marquez, A; Gallego, S; Neipp, C; Belendez, A, E-mail: a.belendez@ua.es [Departamento de Fisica, IngenierIa de Sistemas y TeorIa de la Senal, Universidad de Alicante, Apartado 99, E-03080 Alicante (Spain)

    2011-07-15

    An experimental apparatus was designed and built to allow students to carry out heat conduction experiments in hollow cylinders made of different materials, as well as to determine the thermal conductivity of these materials. The evolution of the temperature difference between the inner and outer walls of the cylinder as a function of time is analysed, and when the process reaches the steady state regime the thermal conductivity can be easily calculated. Several materials such as wood, plastic and metals are considered and the values of their thermal conductivities, obtained experimentally, are compared with those given in the reference list.

  18. 国电库车发电厂空冷塔X柱及筒壁施工工艺%Construction Craft of the Air-cooling Tower X Column and Cylinder Wall in Guodian Kuche Power Plant

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    The Guodian Kuche power plant air-cooling tower is the largest air-cooling tower in Xinjiang, the height of air-cooling tower X pil ar is 26m, section is big and inclined 70 DEG, supporting rack erection is complex; the height of cylin-der wal is 157 m, vertical transportation difficulty is big, quan-tities is large, radius is large, horizontal transportation has gr-eat dif iculty. We use the advanced construction technology, improve the efficiency of work.%  国电库车发电厂空冷塔为全疆最大的空冷塔,空冷塔 X 支柱高度26 m、截面大并倾斜70°,支撑排架搭设复杂;筒壁高度157m、垂直运输难度大、工程量大、半径大、水平运输难度大。我们采用了先进的施工工艺,提高了工作效益。

  19. Numerical Simulation and Flow Behaviors of Taylor Flow in Co-Axial Rotating Cylinder

    Directory of Open Access Journals (Sweden)

    Sheng Chung Tzeng

    2014-04-01

    Full Text Available This work uses the incense as the trace of flow to perform flow visualization of Taylor-Couette flow. The test section was made of a rotational inner cylinder and a stationary outer cylinder. Two modes of inner cylinder were employed. One had a smooth wall, and the other had an annular ribbed wall. Clear and complete Taylor vortices were investigated in both smooth and ribbed wall of co-axial rotating cylinder. Besides, a steady-state, axis-symmetrical numerical model was provided to simulate the present flow field. The Taylor vortices could be also successfully predicted. However, the assumption of steady-state flow might reduce some flow perturbations, resulting in an over-predicted critical Taylor number. A transient simulation is suggested to be performed in the future.

  20. Rolling Cylinder Phase 1bis

    DEFF Research Database (Denmark)

    Margheritini, Lucia

    Cylinder Phase 1: proof of concept and first optimization”, DCE report 115, ISSN 1901-726X, and it is recommended that the two are consulted together as they were firstly agreed to be in one document. The present report aims at estimate the efficiency of the Rolling Cylinder long model (previously...

  1. Natural convection from circular cylinders

    CERN Document Server

    Boetcher, Sandra K S

    2014-01-01

    This book presents a concise, yet thorough, reference for all heat transfer coefficient correlations and data for all types of cylinders: vertical, horizontal, and inclined. This book covers all natural convection heat transfer laws for vertical and inclined cylinders and is an excellent resource for engineers working in the area of heat transfer engineering.

  2. Approximation of Surfaces by Cylinders

    DEFF Research Database (Denmark)

    Randrup, Thomas

    1998-01-01

    We present a new method for approximation of a given surface by a cylinder surface. It is a constructive geometric method, leading to a monorail representation of the cylinder surface. By use of a weighted Gaussian image of the given surface, we determine a projection plane. In the orthogonal...

  3. Relevant surgical anatomy of the chest wall.

    Science.gov (United States)

    Naidu, Babu V; Rajesh, Pala B

    2010-11-01

    The chest wall, like other regional anatomy, is a remarkable fusion of form and function. Principal functions are the protection of internal viscera and an expandable cylinder facilitating variable gas flow into the lungs. Knowledge of the anatomy of the whole cylinder (ribs, sternum, vertebra, diaphragm, intercostal spaces, and extrathoracic muscles) is therefore not only important in the local environment of a specific chest wall resection but also in its relation to overall function. An understanding of chest wall kinematics might help define the loss of function after resection and the effects of various chest wall substitutes. Therefore, this article is not an exhaustive anatomic description but a focused summary and discussion.

  4. Feasibility of Integrated Insulation in Rammed Earth

    Science.gov (United States)

    Stone, C.; Balintova, M.; Holub, M.

    2015-11-01

    Building Codes in Europe stipulate strict thermal performance criteria which any traditional rammed earth recipe cannot meet. This does not infer that the material itself is inferior; it has many other face saving attributes such as low embodied energy, high workability, sound insulation, fire resistance, aesthetics, high diffusivity and thermal accumulation properties. Integrated insulation is experimented with, to try achieve a 0.22 [W/(m2.K)] overall coefficient of heat transfer for walls required by 2015 Slovak standards, without using external insulation or using technologically complex interstitial insulation. This has the added aesthetic benefit of leaving the earth wall exposed to the external environment. Results evaluate the feasibility of this traditional approach.

  5. Analyzing screen heat insulation and its effect on energy consumption while heating building envelopes in conditions of intermittent heating

    Directory of Open Access Journals (Sweden)

    Vytchikov Yuri

    2016-01-01

    Full Text Available The paper is devoted to screen heat insulation and its effect on energy consumption while heating building envelopes in conditions of intermittent heating. It also describes the non-stationary process of heat transfer through heat insulated outer walls. The authors introduce calculation results of specific energy consumption for heating insulated and non-insulted outer walls. The paper proves that energy consumption for heating insulated outer walls depends on the thickness of non-aerated air-space insulation The research shows positive effects of using thermal protection systems with screen thermal insulation in outer building envelopes in conditions of intermitten heating.

  6. Test Study on Insulation Performance of Straw Panel and Rock Wool Used in the Wood Frame Shear Wall%基于秸秆、岩棉材料的木框架剪力墙保温性能试验研究

    Institute of Scientific and Technical Information of China (English)

    刘雁; 郭楷; 周超; 李娟

    2013-01-01

    Crops straw can be produced as wall insulation materials. The insulation performance of straw panel and rock wool used in the wood frame shear wall was tested and analyzed, and the heat transfer coefficient K0 of two different materials was obtained, both of them will satisfy the current national code. The research conclusion verifies the straw panel is available as the thermal insulation material.%农作物秸秆经过工厂的生产加工,可以制作成新型墙体保温材料。通过在木框架剪力墙墙体中分别放置秸秆板和岩棉,对其进行保温性能的试验和分析,得出秸秆板和岩棉墙体传热系数K0都符合国家规范K≤1.0的要求。试验研究为秸秆板在保温材料领域中的应用提供依据。

  7. Effective Hamiltonian for surface states of topological insulator nanotubes

    Science.gov (United States)

    Siu, Zhuo Bin; Tan, Seng Ghee; Jalil, Mansoor B. A.

    2017-04-01

    In this work we derive an effective Hamiltonian for the surface states of a hollow topological insulator (TI) nanotube with finite width walls. Unlike a solid TI cylinder, a TI nanotube possesses both an inner as well as outer surface on which the states localized at each surface are coupled together. The curvature along the circumference of the nanotube leads to a spatial variation of the spin orbit interaction field experienced by the charge carriers as well as an asymmetry between the inner and outer surfaces of the nanotube. Both of these features result in terms in the effective Hamiltonian for a TI nanotube absent in that of a flat TI thin film of the same thickness. We calculate the numerical values of the parameters for a Bi2Se3 nanotube as a function of the inner and outer radius, and show that the differing relative magnitudes between the parameters result in qualitatively differing behaviour for the eigenstates of tubes of different dimensions.

  8. 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...

  9. 新型现浇自保温墙体材料的力学性能试验研究%New type self-thermal insulation wall materials mechanical properties experiments

    Institute of Scientific and Technical Information of China (English)

    杨伟军; 张婷婷; 朱检; 范辉

    2014-01-01

    With modified powder polystyrene particles being used as integral cast in-situ pouring material ,the pulling fastening extru-sion bolted wall has the following advantages:light in weight,heat preservation,sound insulation,fire-proof,combined with effectively re-duce the labor intensity and enhance construction efficiency.However its material mechanical properties is unclear. Aim to provide neces-sary parameters and mechanical properties for its popularization and application ,the authors designed series experiments concerning the compressive strength,bending,tensile,pulling and elasticity modulus tests. Results showed that under the state of gas-dry ,the compressive strength of materials decrease exponentially with the the attenuation of dry density and were irrelevant to the moisture content. Material folding ratio,split ratio and elastic modulus were far greater than that of other materials. The material was characterized by good flexibili-ty,good unti-deformation performance.Limit drawing force and limit drawing strength index of the materials were obtained and then ex-plained the selection and installation process of expansion bolt.This kind of material can be used as interior nonbearing wall ,energy-saving integration of structure heat preservation material,compound to the shear wall,column and beam and other thermal bridge. It has certain value of reference for engineering materials applications.%以改性胶粉聚苯颗粒为浇筑料,整体现浇,对拉螺栓紧固挤压成型的墙体,其质轻保温、隔声耐火,可有效降低劳动强度,提高施工效率。设计了抗压、抗折、抗拉、拉拔和弹性模量的试验。研究结果表明:气干状态下,材料的抗压强度随干密度降低呈指数衰减,与含水率并无规律可寻;材料的折压比、劈压比和弹性模量远大于同类型材料,材料韧性好,抵抗变形能力强;获得材料的极限拉拔力和拉拔强度指标,并对膨胀螺栓的

  10. Prediction of External Corrosion for Steel Cylinders 2001 Report

    Energy Technology Data Exchange (ETDEWEB)

    Schmoyer, RLS

    2001-09-17

    The United States Department of Energy (DOE) currently manages the UF{sub 6} Cylinder Project. The project was formed to maintain and safely manage the depleted uranium hexafluoride (UF{sub 6}) stored in approximately 50,000 carbon steel cylinders. The cylinders are located at three DOE sites: the ETTP site (K-25) at Oak Ridge, Tennessee; the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The System Requirements Document (SRD) (LMES 1997a) delineates the requirements of the project. The appropriate actions needed to fulfill these requirements are then specified within the System Engineering Management Plan (SEMP) (LMES 1997b). This report documents activities that in whole or in part satisfy specific requirements and actions stated in the UF{sub 6} Cylinder Project SRD and SEMP with respect to forecasting cylinder conditions. The results presented here supercede those presented previously (Lyon 1995, 1996, 1997, 1998, 2000). Many of the wall thickness projections made in this report are conservative, because they are based on the assumption that corrosion trends will continue, despite activities such as improved monitoring, relocations to better storage, and painting.

  11. Scalar cylinder-plate and cylinder-cylinder Casimir interaction in higher dimensional spacetime

    CERN Document Server

    Teo, L P

    2015-01-01

    We study the cylinder-plate and the cylinder-cylinder Casimir interaction in the $(D+1)$-dimensional Minkowski spacetime due to the vacuum fluctuations of massless scalar fields. Different combinations of Dirichlet (D) and Neumann (N) boundary conditions are imposed on the two interacting objects. For the cylinder-cylinder interaction, we consider the case where one cylinder is inside the other, and the case where the two cylinders are outside each other. By computing the transition matrices of the objects and the translation matrices that relate different coordinate systems, the explicit formulas for the Casimir interaction energies are derived. Using perturbation technique, we compute the small separation asymptotic expansions of the Casimir interaction energies up to the next-to-leading order terms. The leading terms coincide with the respective results obtained using proximity force approximation, which is of order $d^{-D+1/2}$, where $d$ is the distance between the two objects. The results on the next-to...

  12. Criticality experiments with annular cylinders containing plutonium solutions; Experiences de criticite sur des cylindres annulaires contenant des solutions de plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Molbert, M.; Sauve, A.; Houelle, M.; Deilgat, E. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The criticality station of Dijon involves three cells, shielded by concrete walls of 1.46 meter thickness. Those cells are designed to contain the criticality experiment apparatus. The engineering building is also involving: one chemical laboratory where plutonium solutions are prepared, one analysis laboratory, several activated solutions storages, several control rooms, One cell contains the B system, which is designed to study: annular cylindrical geometries, slab of 10 cm thickness, interaction between annular cylinders. This report includes the first results given by experiments on annular cylinders defined by their own geometry (outer and inner diameter of ring containing plutonium solutions). Those results have been plotted in curves, for several concentrations and for different reflection conditions (outer or inner light water reflector, cadmium screen), H{sub c} and M{sub c} = f (c) (where H{sub c} is the critical height of solution, M{sub c} is the critical mass, c is the plutonium concentration: 42,3 g/lcylinders 500 x 300 -- an insulated cylinder --interaction between two annular cylinders. In this last case, the curves have been plotted for three concentrations in plutonium and give H{sub c} and M{sub c} versus the distance between the two solutions. - an insulated annular cylinder 500 x 200: incomplete results are published the experiments on this cylinder being unfinished to the date of this present report publication. On this miscellaneous results, we have following informations know: - Screen effect of light water in central hole. Strengthened effect by cadmium foil on the inside wall. - Normalized interaction curves ( {alpha}*H{sub c}/H{sub c{infinity}} ) versus the distance between the two vessels, where H{sub c{infinity}} critical height of an insulated cylinder, shows that: 1) In light water, two cylinders set aside from 15 cm, can be considers like separated. 2) For some configurations, {alpha} vary

  13. Criticality experiments with annular cylinders containing plutonium solutions; Experiences de criticite sur des cylindres annulaires contenant des solutions de plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Molbert, M.; Sauve, A.; Houelle, M.; Deilgat, E. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The criticality station of Dijon involves three cells, shielded by concrete walls of 1.46 meter thickness. Those cells are designed to contain the criticality experiment apparatus. The engineering building is also involving: one chemical laboratory where plutonium solutions are prepared, one analysis laboratory, several activated solutions storages, several control rooms, One cell contains the B system, which is designed to study: annular cylindrical geometries, slab of 10 cm thickness, interaction between annular cylinders. This report includes the first results given by experiments on annular cylinders defined by their own geometry (outer and inner diameter of ring containing plutonium solutions). Those results have been plotted in curves, for several concentrations and for different reflection conditions (outer or inner light water reflector, cadmium screen), H{sub c} and M{sub c} = f (c) (where H{sub c} is the critical height of solution, M{sub c} is the critical mass, c is the plutonium concentration: 42,3 g/lcylinders 500 x 300 -- an insulated cylinder --interaction between two annular cylinders. In this last case, the curves have been plotted for three concentrations in plutonium and give H{sub c} and M{sub c} versus the distance between the two solutions. - an insulated annular cylinder 500 x 200: incomplete results are published the experiments on this cylinder being unfinished to the date of this present report publication. On this miscellaneous results, we have following informations know: - Screen effect of light water in central hole. Strengthened effect by cadmium foil on the inside wall. - Normalized interaction curves ( {alpha}*H{sub c}/H{sub c{infinity}} ) versus the distance between the two vessels, where H{sub c{infinity}} critical height of an insulated cylinder, shows that: 1) In light water, two cylinders set aside from 15 cm, can be considers like separated. 2) For some configurations, {alpha} vary

  14. Experimental study on free convection of sodium in a long cylinder

    Science.gov (United States)

    Kolesnichenko, I. V.; Mamykin, A. D.; Pavlinov, A. M.; Pakholkov, V. V.; Rogozhkin, S. A.; Frick, P. G.; Khalilov, R. I.; Shepelev, S. F.

    2015-06-01

    The operation experience of sodium fast reactor shows that during design-basis validation of pipelines and equipment it is necessary to take into account the sodium free convection in the enclosures. The paper presents the results of experimental study of free convection of liquid sodium in a long thermo-insulated cylinder with the end heat supply and removal. The sodium-filled cylinder diameter is 168 mm, length is 850 mm. Three experiments for horizontal, inclined (at 45° to a vertical line) and vertical position of the cylinder were compared in detail. The Rayleigh number (based on cylinder diameter) is approximately same for three experiments and is equal to 5 × 106. The structure of large-scale and small-scale flows was analyzed. Nusselt number estimations being the intensity measure of heat transfer in case of free convection were obtained. A relationship between the flow structure and the Nusselt number is revealed.

  15. Approximation of Surfaces by Cylinders

    DEFF Research Database (Denmark)

    Randrup, Thomas

    1998-01-01

    We present a new method for approximation of a given surface by a cylinder surface. It is a constructive geometric method, leading to a monorail representation of the cylinder surface. By use of a weighted Gaussian image of the given surface, we determine a projection plane. In the orthogonal...... projection of the surface onto this plane, a reference curve is determined by use of methods for thinning of binary images. Finally, the cylinder surface is constructed as follows: the directrix of the cylinder surface is determined by a least squares method minimizing the distance to the points...... in the projection within a tolerance given by the reference curve, and the rulings are lines perpendicular to the projection plane. Application of the method in ship design is given....

  16. Innovative Retrofit Insulation Strategies for Concrete Masonry Foundations

    Energy Technology Data Exchange (ETDEWEB)

    Huelman, P. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Goldberg, L. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Jacobson, R. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership

    2015-05-06

    This study was designed to test a new approach for foundation insulation retrofits, with the goal of demonstrating improved moisture control, improved occupant comfort, and reduced heat loss. Because conducting experimental research on existing below-grade assemblies is very difficult, most of the results are based on simulations. The retrofit approach consists of filling open concrete block cores with an insulating material and adding R-10 exterior insulation that extends 1 ft below grade. The core fill is designed to improve the R-value of the foundation wall and increase the interior wall surface temperature, but more importantly to block convection currents that could otherwise increase moisture loads on the foundation wall and interior space. The exterior insulation significantly reduces heat loss through the most exposed part of the foundation and further increases the interior wall surface temperature. This improves occupant comfort and decreases the risk of condensation. Such an insulation package avoids the full-depth excavation necessary for exterior insulation retrofits, reduces costs, and eliminates the moisture and indoor air quality risks associated with interior insulation retrofits. Retrofit costs for the proposed approach were estimated at roughly half those of a full-depth exterior insulation retrofit.

  17. Numerical study on ring bubble dynamics in a narrow cylinder with a compliant coating

    Energy Technology Data Exchange (ETDEWEB)

    Farhangmehr, V; Shervani-Tabar, M T [Department of Mechanical Engineering, University of Tabriz, Tabriz (Iran, Islamic Republic of); Parvizi, R [Department of Cardiac Surgery, Shahid Madani Heart Hospital, Tabriz (Iran, Islamic Republic of); Ohl, S W [Institute of High Performance Computing, 1 Fusinopolis Way, #16-16 Connexis, Singapore 138632 (Singapore); Khoo, B C, E-mail: vfarhangmehr@gmail.com [Department of Mechanical Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260 (Singapore)

    2015-04-15

    In this paper, the ring bubble contraction inside a narrow vertical rigid cylinder with a compliant coating filled with water is studied numerically. To simulate ring bubble dynamics numerically, in addition to computing the pressure and velocity fields of the surrounding fluid, an axisymmetric boundary integral equation approach is adopted alongside a finite difference method. The compliant boundary is modeled as a membrane with a spring foundation. During the ring bubble contraction and under the attraction of the cylinder wall due to the Bjerknes force, a horizontal ring jet is initiated and develops towards the cylinder wall. The numerical results represent the effects of the cylinder radius and two compliant coating characteristics, including its mass per unit area and the spring constant, on the ring bubble behavior. This investigation is motivated by the possibility of utilizing the ring jet in therapeutic cardiovascular applications. (paper)

  18. Numerical Investigation on Slot air Jet impingement Heat Transfer between Horizontal Concentric Circular Cylinders

    Directory of Open Access Journals (Sweden)

    Arash Azimi

    2015-04-01

    Full Text Available Numerical study has been carried out for slot air jet impingement cooling of horizontal concentric circular cylinders. The slot air jet is situated at the symmetry line of a horizontal cylinder along the gravity vector and impinges to the bottom of the outer cylinder which is designated as θ=0°. The outer cylinder is partially opened at the top with width of W=30mm and is kept at constant temperature T= 62°C. Inner cylinder which is a part of the slot jet structure is chosen to be insulated. The effects of jet Reynolds number in the range of 100≤ Rej ≤1000 and the ratio of spacing between nozzle and outer cylinder surface to the jet width for H=4.2 and H=12.5 on the local and average Nusselt numbers are examined. In the numerical study, FLUENT CFD package is used and validated by comparing the results with the experimental data at the same Reynolds number. It is observed that the maximum Nusselt number occurs at the stagnation point at (θ=0° and the local heat transfer coefficient decrease on the circumference of the cylinder with increase of θ as a result of thermal boundary layer thickness growth. Also results show that the local and average heat transfer coefficients are raised by increasing the jet Reynolds number and by decreasing the nozzle-to-surface spacing.

  19. Development of Advanced In-Cylinder Components and Tribological Systems for Low Heat Rejection Diesel Engines

    Science.gov (United States)

    Yonushonis, T. M.; Wiczynski, P. D.; Myers, M. R.; Anderson, D. D.; McDonald, A. C.; Weber, H. G.; Richardson, D. E.; Stafford, R. J.; Naylor, M. G.

    1999-01-01

    In-cylinder components and tribological system concepts were designed, fabricated and tested at conditions anticipated for a 55% thermal efficiency heavy duty diesel engine for the year 2000 and beyond. A Cummins L10 single cylinder research engine was used to evaluate a spherical joint piston and connecting rod with 19.3 MPa (2800 psi) peak cylinder pressure capability, a thermal fatigue resistant insulated cylinder head, radial combustion seal cylinder liners, a highly compliant steel top compression ring, a variable geometry turbocharger, and a microwave heated particulate trap. Components successfully demonstrated in the final test included spherical joint connecting rod with a fiber reinforced piston, high conformability steel top rings with wear resistant coatings, ceramic exhaust ports with strategic oil cooling and radial combustion seal cylinder liner with cooling jacket transfer fins. A Cummins 6B diesel was used to develop the analytical methods, materials, manufacturing technology and engine components for lighter weight diesel engines without sacrificing performance or durability. A 6B diesel engine was built and tested to calibrate analytical models for the aluminum cylinder head and aluminum block.

  20. Thermal Insulation System for Large Flame Buckets

    Science.gov (United States)

    Callens, E. Eugene, Jr.; Gamblin, Tonya Pleshette

    1996-01-01

    The objective of this study is to investigate the use of thermal protection coatings, single tiles, and layered insulation systems to protect the walls of the flame buckets used in the testing of the Space Shuttle Main Engine, while reducing the cost and maintenance of the system. The physical behavior is modeled by a plane wall boundary value problem with a convective frontface condition and a backface condition designed to provide higher heat rates through the material.

  1. Composite aerogel insulation for cryogenic liquid storage

    Science.gov (United States)

    Kyeongho, Kim; Hyungmook, Kang; Soojin, Shin; In Hwan, Oh; Changhee, Son; Hyung, Cho Yun; Yongchan, Kim; Sarng Woo, Karng

    2017-02-01

    High porosity materials such as aerogel known as a good insulator in a vacuum range (10-3 ∼ 1 Torr) was widely used to storage and to transport cryogenic fluids. It is necessary to be investigated the performance of aerogel insulations for cryogenic liquid storage in soft vacuum range to atmospheric pressure. A one-dimensional insulating experimental apparatus was designed and fabricated to consist of a cold mass tank, a heat absorber and an annular vacuum space with 5-layer (each 10 mm thickness) of the aerogel insulation materials. Aerogel blanket for cryogenic (used maximum temperature is 400K), aerogel blanket for normal temperature (used maximum temperature is 923K), and combination of the two kinds of aerogel blankets were 5-layer laminated between the cryogenic liquid wall and the ambient wall in vacuum space. Also, 1-D effective thermal conductivities of the insulation materials were evaluated by measuring boil-off rate from liquid nitrogen and liquid argon. In this study, the effective thermal conductivities and the temperature-thickness profiles of the two kinds of insulators and the layered combination of the two different aerogel blankets were presented.

  2. Axisymmetric instability of the Poiseuille-Couette flow between concentric cylinders at high Reynolds numbers

    Science.gov (United States)

    Savenkov, I. V.

    2015-02-01

    For the pressure-driven flow in an annular channel with a wall moving in the axial direction, its linear instability with respect to axisymmetric perturbations at high Reynolds numbers is investigated within the framework of the triple-deck theory. When the gap between the cylinders is sufficiently small (as compared to the radii of the cylinders), it is shown that the perturbations can split into two wave packets, the first of which grows faster and moves at a higher velocity.

  3. Piezoelectric sensors to monitor lubricant film thickness at piston-cylinder contacts in a fired engine

    OpenAIRE

    2013-01-01

    The contact between the piston ring and cylinder liner is the most important sealing interface in an automotive engine. Understanding the contact interactions and lubricant film formation at this interface is crucial for the development of fuel-efficient and low emission engines. This article outlines the development of an ultrasonic approach to enable non-invasive measurement of the lubricant film thickness formed between piston and cylinder wall of a fired engine. The sensor system consiste...

  4. Study of influence of an experiment scale on cylinder test results

    Directory of Open Access Journals (Sweden)

    Waldemar A. Trzciński

    2014-03-01

    Full Text Available In the work, influence of a scale of experiment on the results of cylindrical test used todetermine the acceleration capabilities of explosives was analyzed. Explosives used in ammunition(TNT, hexogen and explosives for civil purpose (ammonals were selected for testing. Copper tubeswith different diameters and wall thickness were used. Conclusions are drawn regarding the advisabilityof increasing or decreasing the scale of the cylinder test.[b]Keywords[/b]: explosives, acceleration ability, cylinder test

  5. Induced-charge electroosmosis around conducting and Janus cylinder in microchip

    Directory of Open Access Journals (Sweden)

    Zhang Kai

    2012-01-01

    Full Text Available The induced-charge elecetroosmosis around conducting/Janus cylinder with arbitrary Debye thickness is studied numerically, when an direct current weak electric filed is suddenly applied in a confined microchannel. It’s found that there are four large circulations around the conducting cylinder, and the total flux in the microchannel is zero; there are two smaller circulations around the Janus cylinder, and they are compressed to wall. A bulk flux, which has a parabolic relation with the applied electric field, is also predicted.

  6. High Performance Walls in Hot-Dry Climates

    Energy Technology Data Exchange (ETDEWEB)

    Hoeschele, M.; Springer, D.; Dakin, B.; German, A.

    2015-01-01

    High performance walls represent a high priority measure for moving the next generation of new homes to the Zero Net Energy performance level. The primary goal in improving wall thermal performance revolves around increasing the wall framing from 2x4 to 2x6, adding more cavity and exterior rigid insulation, achieving insulation installation criteria meeting ENERGY STAR's thermal bypass checklist, and reducing the amount of wood penetrating the wall cavity.

  7. Actuator placement for active sound and vibration control of cylinders

    Science.gov (United States)

    Kincaid, Rex K.

    1995-01-01

    Active structural acoustic control is a method in which the control inputs (used to reduce interior noise) are applied directly to a vibrating structural acoustic system. The control concept modeled in this work is the application of in-plane force inputs to piezoceramic patches bonded to the wall of a vibrating cylinder. The cylinder is excited by an exterior noise source -- an acoustic monopole -- located near the outside of the cylinder wall. The goal is to determine the force inputs and sites for the piezoelectric actuators so that (1) the interior noise is effectively damped; (2) the level of vibration of the cylinder shell is not increased; and (3) the power requirements needed to drive the actuators are not excessive. We studied external monopole excitations at two frequencies. A cylinder resonance of 100 Hz, where the interior acoustic field is driven in multiple, off-resonance cylinder cavity modes, and a cylinder resonance of 200 Hz are characterized by both near and off-resonance cylinder vibration modes which couple effectively with a single, dominant, low-order acoustic cavity mode at resonance. Previous work has focused almost exclusively on meeting objective (1) and solving a complex least-squares problem to arrive at an optimal force vector for a given set of actuator sites. In addition, it has been noted that when the cavity mode couples with cylinder vibration modes (our 200 Hz case) control spillover may occur in higher order cylinder shell vibrational modes. How to determine the best set of actuator sites to meet objectives (1)-(3) is the main contribution of our research effort. The selection of the best set of actuator sites from a set of potential sites is done via two metaheuristics -- simulated annealing and tabu search. Each of these metaheuristics partitions the set of potential actuator sites into two disjoint sets: those that are selected to control the noise (on) and those that are not (off). Next, each metaheuristic attempts to

  8. Rotation of an immersed cylinder sliding near a thin elastic coating

    Science.gov (United States)

    Rallabandi, Bhargav; Saintyves, Baudouin; Jules, Theo; Salez, Thomas; Schönecker, Clarissa; Mahadevan, L.; Stone, Howard A.

    2017-07-01

    It is known that an object translating parallel to a soft wall in a viscous fluid produces hydrodynamic stresses that deform the wall, which in turn results in a lift force on the object. Recent experiments with cylinders sliding under gravity near a soft incline, which confirmed theoretical arguments for the lift force, also reported an unexplained steady-state rotation of the cylinders [B. Saintyves et al., Proc. Natl. Acad. Sci. USA 113, 5847 (2016), 10.1073/pnas.1525462113]. Motivated by these observations, we show, in the lubrication limit, that an infinite cylinder that translates in a viscous fluid parallel to a soft wall at constant speed and separation distance must also rotate in order to remain free of torque. Using the Lorentz reciprocal theorem, we show analytically that for small deformations of the elastic layer, the angular velocity of the cylinder scales with the cube of the sliding speed. These predictions are confirmed numerically. We then apply the theory to the gravity-driven motion of a cylinder near a soft incline and find qualitative agreement with the experimental observations, namely, that a softer elastic layer results in a greater angular speed of the cylinder.

  9. Pressure cylinders under fire condition

    Directory of Open Access Journals (Sweden)

    Jan Hora

    2016-03-01

    Full Text Available The presence of pressure cylinders under fire conditions significantly increases the risk rate for the intervening persons. It is considerably problematic to predict the pressure cylinders behaviour during heat exposition, its destruction progress and possible following explosion of the produced air–gas mixture because pressure cylinders and its environment generate a highly complicated dynamic system during an uncontrolled destruction. The large scale tests carried out by the Pilsen Fire and Rescue Department and the Rapid Response Unit of the Czech Republic Police in October 2012 and in May 2014 in the Military area Brdy and in the area of the former Lachema factory in Kaznějov had several objectives, namely, to record, qualify and quantify some of the aspects of an uncontrolled heat destruction procedure of an exposed pressure cylinder in an enclosed space and to qualify and describe the process of a controlled destruction of a pressure cylinder by shooting through it including basic tactical concepts. The article describes the experiments that were carried out.

  10. Results of the remote sensing feasibility study for the uranium hexafluoride storage cylinder yard program

    Energy Technology Data Exchange (ETDEWEB)

    Balick, L.K.; Bowman, D.R. [Bechtel Nevada, Las Vegas, NV (United States). Remote Sensing Lab.; Bounds, J.H. [Los Alamos National Lab., NM (United States)] [and others

    1997-02-01

    The US DOE manages the safe storage of approximately 650,000 tons of depleted uranium hexafluoride remaining from the Cold War. This slightly radioactive, but chemically active, material is contained in more than 46,000 steel storage cylinders that are located at Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. Some of the cylinders are more than 40 years old, and approximately 17,500 are considered problem cylinders because their physical integrity is questionable. These cylinders require an annual visual inspection. The remainder of the 46,000-plus cylinders must be visually inspected every four years. Currently, the cylinder inspection program is extremely labor intensive. Because these inspections are accomplished visually, they may not be effective in the early detection of leaking cylinders. The inspection program requires approximately 12--14 full-time-equivalent (FTE) employees. At the cost of approximately $125K per FTE, this translates to $1,500K per annum just for cylinder inspection. As part of the technology-development portion of the DOE Cylinder Management Program, the DOE Office of Facility Management requested the Remote Sensing Laboratory (RSL) to evaluate remote sensing techniques that have potential to increase the effectiveness of the inspection program and, at the same time, reduce inspection costs and personnel radiation exposure. During two site visits (March and May 1996) to the K-25 Site at Oak Ridge, TN, RSL personnel tested and characterized seven different operating systems believed to detect leakage, surface contamination, thickness and corrosion of cylinder walls, and general area contamination resulting from breached cylinders. The following techniques were used and their performances are discussed: Laser-induced fluorescent imaging; Long-range alpha detection; Neutron activation analysis; Differential gamma-ray attenuation; Compton scatterometry; Active infrared inspection; and Passive thermal infrared imaging.

  11. Excavationless Exterior Foundation Insulation Field Study

    Energy Technology Data Exchange (ETDEWEB)

    Schirber, T. [NorthernSTAR, Minneaplolis, MN (United States); Mosiman, G. [NorthernSTAR, Minneaplolis, MN (United States); Ojczyk, C. [NorthernSTAR, Minneaplolis, MN (United States)

    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 liquid insulating foam. The team was able to excavate a continuous 4 inches wide by 4 feet to 5 feet 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.

  12. Excavationless Exterior Foundation Insulation Field Study

    Energy Technology Data Exchange (ETDEWEB)

    Schirber, T.; Mosiman, G.; Ojczyk, C.

    2014-10-01

    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.

  13. Technology Solutions for New and Existing Homes Case Study: Optimized Slab-on-Grade Foundation Insulation Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Schirber, T. [NorthernSTAR Buidling American Partnership, Madison, WI (United States); Goldberg, L. [NorthernSTAR Buidling American Partnership, Madison, WI (United States); Mosiman, G. [NorthernSTAR Buidling American Partnership, Madison, WI (United States)

    2016-05-01

    A more accurate assessment of SOG foundation insulation energy savings than traditionally possible is now feasible. This has been enabled by advances in whole building energy simulation with 3-dimensional foundation modelling integration at each time step together with an experimental measurement of the site energy savings of SOG foundation insulation. Ten SOG insulation strategies were evaluated on a test building to identify an optimum retrofit insulation strategy in a zone 6 climate (Minneapolis, MN). The optimum insulation strategy in terms of energy savings and cost effectiveness consisted of two components: (a) R-20 XPS insulation above grade, and, (b) R-20 insulation at grade (comprising an outer layer of R-10 insulation and an interior layer of R-12 poured polyurethane insulation) tapering to R-10 XPS insulation at half the below-grade wall height (the lower half of the stem wall was uninsulated).

  14. Blower Cooling of Finned Cylinders

    Science.gov (United States)

    Schey, Oscar W; Ellerbrock, Herman H , Jr

    1937-01-01

    Several electrically heated finned steel cylinders enclosed in jackets were cooled by air from a blower. The effect of the air conditions and fin dimensions on the average surface heat-transfer coefficient q and the power required to force the air around the cylinders were determined. Tests were conducted at air velocities between the fins from 10 to 130 miles per hour and at specific weights of the air varying from 0.046 to 0.074 pound per cubic foot. The fin dimensions of the cylinders covered a range in pitches from 0.057 to 0.25 inch average fin thicknesses from 0.035 to 0.04 inch, and fin widths from 0.67 to 1.22 inches.

  15. Filament winding cylinders. I - Process model

    Science.gov (United States)

    Lee, Soo-Yong; Springer, George S.

    1990-01-01

    A model was developed which describes the filament winding process of composite cylinders. The model relates the significant process variables such as winding speed, fiber tension, and applied temperature to the thermal, chemical and mechanical behavior of the composite cylinder and the mandrel. Based on the model, a user friendly code was written which can be used to calculate (1) the temperature in the cylinder and the mandrel, (2) the degree of cure and viscosity in the cylinder, (3) the fiber tensions and fiber positions, (4) the stresses and strains in the cylinder and in the mandrel, and (5) the void diameters in the cylinder.

  16. PERCOLATION OF RANDOM CYLINDER AGGREGATES

    Directory of Open Access Journals (Sweden)

    Dominique Jeulin

    2011-05-01

    Full Text Available The percolation threshold ρc of Boolean models of cylinders with their axis parallel to a given direction is studied by means of simulations. An efficient method of construction of percolating connected components was developed, and is applied to one or two scales Boolean model, in order to simulate the presence of aggregates. The invariance of the percolation threshold with respect to affine transformations in the common direction of the axis of cylinders is approximately satisfied on simulations. The prediction of the model (ρc close to 0.16 is consistent with experimental measurements on plasma spray coatings, which motivated this study.

  17. Evaluation of conjugate, radial heat transfer in an internally insulated composite pipe

    NARCIS (Netherlands)

    Reurings, C.; Koussios, S.; Bergsma, O.K.; Vergote, K.

    2015-01-01

    In order to compete with steel, a fibre-reinforced composite exhaust wall with a general-purpose resin system requires an effective but lightweight insulation layer. However a lack of experimental methods for heat transfer from turbulent gas flow to pipe walls lined with a porous insulation layer wa

  18. Evaluation of conjugate, radial heat transfer in an internally insulated composite pipe

    NARCIS (Netherlands)

    Reurings, C.; Koussios, S.; Bergsma, O.K.; Vergote, K.

    2015-01-01

    In order to compete with steel, a fibre-reinforced composite exhaust wall with a general-purpose resin system requires an effective but lightweight insulation layer. However a lack of experimental methods for heat transfer from turbulent gas flow to pipe walls lined with a porous insulation layer

  19. On the inverse Magnus effect for flow past a rotating cylinder

    Science.gov (United States)

    John, Benzi; Gu, Xiao-Jun; Barber, Robert W.; Emerson, David R.

    2016-11-01

    Flow past a rotating cylinder has been investigated using the direct simulation Monte Carlo method. The study focuses on the occurrence of the inverse Magnus effect under subsonic flow conditions. In particular, the variations in the coefficients of lift and drag have been investigated as a function of the Knudsen and Reynolds numbers. Additionally, a temperature sensitivity study has been carried out to assess the influence of the wall temperature on the computed aerodynamic coefficients. It has been found that both the Reynolds number and the cylinder wall temperature significantly affect the drag as well as the onset of lift inversion in the transition flow regime.

  20. Insulated Fiber Brush.

    Science.gov (United States)

    An insulated-strand fiber brush is provided for a DC motor /generator. The brush is comprised of a plurality of fiber segments which are insulated from one another near the contact surface of a rotor bar. In one embodiment, insulating spacers are fixed to a brush assembly and wear with the fibers, and in another embodiment insulation is provided by a separate shell. (Author)

  1. Effect of heat-insulating wall on input energy of a photovoltaic/solar/air-heat system for a residence; Jutaku no kodannetsuka ni yoru taiyoko netsu/taiki netsu system no donyu energy sakugen koka

    Energy Technology Data Exchange (ETDEWEB)

    Kenmoku, Y.; Sakakibara, T. [Toyohashi University of Technology, Aichi (Japan); Nakagawa, S. [Maizuru College of Technology, Kyoto (Japan)

    1996-10-27

    A proposal was made to introduce a photovoltaic/solar/air-heat system which positively utilizes natural energy in order to curtail consumption of fossil energy, corroborating that the system has greatly reduced energy input in the primary energy level in a house. This paper examines the effect of curtailment of energy input in the case of reducing the load of air conditioning through the high heat insulation of a house. The energy input was evaluated by calculating additional equipment energy needed newly for the high heat insulation. The system performance and the energy load varied greatly depending on weather conditions. The subject system consisted of solar cells, inverter, heat concentrator, heat storage tank, heat pump and gas hot-water supply device. The thickening of the insulation sharply reduced heating load in the house, thereby decreasing fuel energy substantially. An insulation material of 100mm thick was capable of reducing energy input by 16-23% compared with that of 50mm thick. 5 refs., 5 figs, 3 tabs.

  2. Large eddy simulation of the subcritical flow over a V grooved circular cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Alonzo-García, A. [Instituto Politécnico Nacional, SEPI-ESIME Zacatenco, U.P. Adolfo López Mateos Edif. 5, 3er. Piso, LABINTHAP, Av. Instituto Politénicno Nacional s/n, Col. Lindavista, C.P. 07738, México D.F., México (Mexico); Gutiérrez-Torres, C. del C., E-mail: cgutierrezt@ipn.mx [Instituto Politécnico Nacional, SEPI-ESIME Zacatenco, U.P. Adolfo López Mateos Edif. 5, 3er. Piso, LABINTHAP, Av. Instituto Politénicno Nacional s/n, Col. Lindavista, C.P. 07738, México D.F., México (Mexico); Jiménez-Bernal, J.A. [Instituto Politécnico Nacional, SEPI-ESIME Zacatenco, U.P. Adolfo López Mateos Edif. 5, 3er. Piso, LABINTHAP, Av. Instituto Politénicno Nacional s/n, Col. Lindavista, C.P. 07738, México D.F., México (Mexico); and others

    2015-09-15

    Highlights: • We compared numerically the turbulent flow over a smooth circular cylinder and a V grooved cylinder in the subcritical regime. • Turbulence intensities in both streamwise and normal direction suffered attenuations. • The swirls structures on grooves peaks seemed to have a cyclic behavior. • The evolution of the flow inside grooves showed that swirls structures located in peaks suffered elongations in the normal direction. • The secondary vortex structures formed in the grooved cylinder near wake were smaller in comparison of the smooth cylinder flow. - Abstract: In this paper, a comparative numerical study of the subcritical flow over a smooth cylinder and a cylinder with V grooves (Re = 140,000) is presented. The implemented technique was the Large Eddy Simulation (LES), which according to Kolmogorov's theory, resolves directly the most energetic largest eddies and models the smallest and considered universal high frequency ones. The Navier-Stokes (N-S) equations were solved using the commercial software ANSYS FLUENT V.12.1, which applied the finite volume method (FVM) to discretize these equations in their unsteady and incompressible forms. The grid densities were 2.6 million cells and 13.5 million cells for the smooth and V grooved cylinder, respectively. Both meshes were composed of structured hexahedral cells and close to the wall of the cylinders, additional refinements were employed in order to obtain y{sup +<5} values. All cases were simulated during at least 15 vortex shedding cycles with the aim of obtaining significant statistical data. Results: showed that for both cases (smooth and V grooved cylinder flow), the numerical code was capable of reproducing the most important physical quantities of the subcritical regime. Velocity distribution and turbulence intensity in the flow direction suffered a slight attenuation along the wake, as a consequence of grooves perturbation, which also caused an increase in the pressure

  3. On certain geodesic conjugacies of flat cylinders

    Indian Academy of Sciences (India)

    C S ARAVINDA; H A GURURAJA

    2017-06-01

    We prove $C^0$-conjugacy rigidity of any flat cylinder among two different classes of metrics on the cylinder, namely among the class of rotationally symmetric metrics and among the class of metrics without conjugate points.

  4. Anisotropic Poisson Processes of Cylinders

    CERN Document Server

    Spiess, Malte

    2010-01-01

    Main characteristics of stationary anisotropic Poisson processes of cylinders (dilated k-dimensional flats) in d-dimensional Euclidean space are studied. Explicit formulae for the capacity functional, the covariance function, the contact distribution function, the volume fraction, and the intensity of the surface area measure are given which can be used directly in applications.

  5. Natural convective heat transfer from square cylinder

    Science.gov (United States)

    Novomestský, Marcel; Smatanová, Helena; Kapjor, Andrej

    2016-06-01

    This article is concerned with natural convective heat transfer from square cylinder mounted on a plane adiabatic base, the cylinders having an exposed cylinder surface according to different horizontal angle. The cylinder receives heat from a radiating heater which results in a buoyant flow. There are many industrial applications, including refrigeration, ventilation and the cooling of electrical components, for which the present study may be applicable

  6. Comparison of aerodynamic noise from three nose-cylinder combinations

    Science.gov (United States)

    Guenther, R. A.; Reding, M. P.

    1970-01-01

    Results of experiments with three different cylinder and blunted nose combinations are discussed. Combinations include smooth cylinder with single 15 deg cone, smooth cylinder with double cone of 25 and 10 deg, and longitudinally corrugated cylinder with similar double cone.

  7. Wake-induced vibrations in Tandem Cylinders

    Science.gov (United States)

    Mysa, Ravi Chaithanya; Jaiman, Rajeev Kumar

    2015-11-01

    The upstream cylinder is fixed in the tandem cylinders arrangement. The downstream cylinder is placed at a distance of four diameters from the upstream cylinder in the free stream direction and is mounted on a spring. The dynamic response of the downstream cylinder is studied at Reynolds number of 10,000. The transverse displacement amplitude of the downstream cylinder is larger compared to that of single cylinder in the post-lock-in region. The transverse dynamic response of the downstream cylinder in the post-lock-in region is characterized by a dominant low frequency component compared to shed frequency, which is nearer to the structural natural frequency. The interaction of upstream wake with the downstream cylinder is carefully analyzed to understand the introduction of low frequency component in the transverse load along with the shed frequency. We found that the stagnation point moves in proportional to the velocity of the cylinder and is in-phase with the velocity. The low frequency component in the stagnation point movement on the downstream cylinder is sustained by the interaction of upstream wake. The frequencies in the movement of the stagnation point is reflected in the transverse load resulting in large deformation of the cylinder. The authors wish to acknowledge support from A*STAR- SERC and Singapore Maritime Institute.

  8. Prediction of external corrosion for steel cylinders at the Paducah Gaseous Diffusion Plant: Application of an empirical method

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, B.F.

    1996-02-01

    During the summer of 1995, ultrasonic wall thickness data were collected for 100 steel cylinders containing depleted uranium (DU) hexafluoride located at Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky. The cylinders were selected for measurement to assess the condition of the more vulnerable portion of the cylinder inventory at PGDP. The purpose of this report is to apply the method used in Lyon to estimate the effects of corrosion for larger unsampled populations as a function of time. The scope of this report is limited and is not intended to represent the final analyses of available data. Future efforts will include continuing analyses of available data to investigate defensible deviations from the conservative assumptions made to date. For each cylinder population considered, two basic types of analyses were conducted: (1) estimates were made of the number of cylinders as a function of time that will have a minimum wall thickness of either 0 mils (1 mil = 0.00 1 in.) or 250 mils and (2) the current minimum wall thickness distributions across cylinders were estimated for each cylinder population considered. Additional analyses were also performed investigating comparisons of the results for F and G yards with the results presented in Lyon (1995).

  9. Karabük İçin Dış Duvar Optimum Yalıtım Kalınlığının Enerji Tasarrufu Ve Hava Kirliliğine Etkileri / The Effect Of External Wall Optimum Insulation Thickness On Energy Saving And Air Pollution For Karabük

    Directory of Open Access Journals (Sweden)

    Ali Etem Gürel

    2012-12-01

    Full Text Available Bina dış duvarlarında yapılacak ısı yalıtım uygulamaları, yakıt tüketimini düşürerek ekonomik kazanç sağlamanın yanında, fosil kaynaklı yakıt kullanımından kaynaklanan ve hava kirliliğine neden olan emisyonların düşürülmesinde de son derece etkilidir. Bu çalışmada Karabük’te kömür ve doğalgaz kullanımında dış duvar optimum yalıtım kalınlığı tespitinin ekonomik ve çevresel analizi yapılmıştır. Çalışmanın ekonomik boyutu, yaşam döngüsü maliyet analizine (LCCA dayanan P1-P2 yöntemi ile gerçekleştirilmiştir. Çalışmanın sonuçları, yakıt olarak kömür kullanıldığında optimum yalıtım kalınlığı ve enerji tasarrufunun sırasıyla 0.135 m ve 129.42 TL/m² olduğunu göstermiştir. Yakıt olarak doğalgaz kullanımında ise bu değerler sırasıyla 0.118 m ve 98.01 TL/m² olarak bulunmuştur. Optimum yalıtım kalınlığının hava kirliliğine olan etkileri incelendiğinde, yalıtımsız bina dış duvarında hesaplanan yıllık yakıt tüketimi, CO2 ve SO2 emisyonlarının yakıt tipine bağlı olarak optimum yalıtım kalınlığı noktasında %86’ya kadar azaldığı hesaplanmıştır. The Effect Of External Wall Optimum Insulation Thickness On Energy Saving And Air Pollution For Karabük Heat insulation applications carried out on external walls of building provides energy saving by decreasing fuel consumption and also quite important in decreasing emission which results from fossil-based fuel usage and causes air pollution. In this study, economic and environmental analyses were done for determination of external wall optimum thickness in using coal and natural gas usage in Karabük. Economic extent of the study was done with P1-P2 method which is based on life cycle cost analysis (LCCA. The results show that optimum insulation thickness and energy saving are 0.134 m and 117.14 TL/m² respectively when coal is used as a fuel. These values are 0.116 m and 88.39 TL

  10. Rotation of an immersed cylinder sliding near a thin elastic coating

    CERN Document Server

    Rallabandi, Bhargav; Jules, Theo; Salez, Thomas; Schönecker, Clarissa; Mahadevan, L; Stone, Howard A

    2016-01-01

    It is well known that an object translating parallel to a soft wall produces viscous stresses and a pressure field that deform the wall, which, in turn, results in a lift force on the object. Recent experiments on cylinders sliding near a soft incline under gravity confirmed previously developed theoretical arguments, but also reported an unexplained rotation of the cylinder at steady state (Saintyves et al. \\emph{PNAS} 113(21), 2016). Here, we use the Lorentz reciprocal theorem to calculate the angular velocity of an infinite cylinder sliding near a soft incline, in the lubrication limit. Our results show that the softness-induced angular velocity of the cylinder is quadratic in the deformation of the elastic layer. This implies that a cylinder sliding parallel to a soft wall without rotation experiences an elastohydrodynamic torque that is proportional to the cube of the sliding speed. We compare the theoretical predictions of the rotation speed with experimental measurements. We then develop scaling and sy...

  11. Building America Case Study: Optimized Slab-on-Grade Foundation Insulation Retrofits, Madison, Wisconsin

    Energy Technology Data Exchange (ETDEWEB)

    2016-05-01

    A more accurate assessment of SOG foundation insulation energy savings than traditionally possible is now feasible. This has been enabled by advances in whole building energy simulation with 3-dimensional foundation modelling integration at each time step together with an experimental measurement of the site energy savings of SOG foundation insulation. Ten SOG insulation strategies were evaluated on a test building to identify an optimum retrofit insulation strategy in a zone 6 climate (Minneapolis, MN). The optimum insulation strategy in terms of energy savings and cost effectiveness consisted of two components: (a) R-20 XPS insulation above grade, and, (b) R-20 insulation at grade (comprising an outer layer of R-10 insulation and an interior layer of R-12 poured polyurethane insulation) tapering to R-10 XPS insulation at half the below-grade wall height (the lower half of the stem wall was uninsulated). The optimum insulation strategy was applied to single and multi-family residential buildings in climate zone 4 - 7. The highest site energy savings of 5% was realized for a single family home in Duluth, MN, and the lowest savings of 1.4 percent for a 4-unit townhouse in Richmond, VA. SOG foundation insulation retrofit simple paybacks ranged from 18 to 47 years. There are other benefits of SOG foundation insulation resulting from the increase in the slab surface temperatures. These include increased occupant thermal comfort, and a decrease in slab surface condensation particularly around the slab perimeter.

  12. Convective Heat Transfer Characteristics of the Elliptic Cylinder with Axis Ratio 4 : 1 in Crossflow

    Institute of Scientific and Technical Information of China (English)

    QI Shou-liang; LI Qing-ling; WANG Ru-zhu

    2005-01-01

    The heat transfer features around the elliptic cylinder of axis ratio 4: 1 in crossflow were investigated experimentally within a wide range of Reynolds number. By means of heat-mass transfer analogy and the naphthalene sublimation technique, the local heat transfer distribution and the mean heat transfer coefficient are clarified.The result shows that the mean heat transfer coefficient is higher than that of a circular cylinder in most Reynolds number range regarded, and this superiority turns to be more significant with the increase of flow speed. Moreover, the effect of axis ratio on mean heat transfer coefficient was investigated tentatively. The oil-lampblack technique was employed to enable visualization of the flow pattern around the cylinder and on the cylinder wall.

  13. Investigation of stress intensity factor for internal cracks in FG cylinders under static and dynamic loading

    Directory of Open Access Journals (Sweden)

    Mahmoud Shariati

    2017-01-01

    Full Text Available his paper investigates the variations of mode I stress intensity factor (KI for inner penny-shaped and circumferential cracks in functionally graded solid and hollow thick walled cylinders, respectively with the changes of crack geometry, material gradation and loading conditions. The functionally graded material of cylinders consists of epoxy and glass. It is assumed that the mechanical properties vary with a power law in the radial direction of cylinders. Micromechanical models for conventional composites are used to estimate the material properties of functionally graded cylinders. The equations of motion obtained from the extended finite element discretization are solved by the Newmark method in the time domain. The interaction integral method is employed to calculate the mode I stress intensity factor (KI. The MATLAB programming environment was implemented to solve the problem.

  14. Building Energy Conservation and Analysis of Rock Wool Exterior Wall Insulation Technology%建筑节能与岩棉外墙外保温技术分析

    Institute of Scientific and Technical Information of China (English)

    高钊

    2014-01-01

    Through an overview of China’s energy situation, this paper dicussed the importance of building energy conservation. Analysised the advantages and disadvantages and performance of rock wool exterior insulation technology.%通过概述我国的能源形势,论述建筑节能的意义,并就岩棉外墙外保温技术的优缺点及性能进行了分析。

  15. Viscous Swirling Flow over a Stretching Cylinder

    Institute of Scientific and Technical Information of China (English)

    Tiegang FANG; ShanshanYAO

    2011-01-01

    We investigate a viscous How over a cylinder with stretching and torsional motion. There is an exact solution to the Navier-Stokes equations and there exists a unique solution for all the given values of the flow Reynolds number. The results show that velocity decays faster for a higher Reynolds number and the How penetrates shallower into the ambient Huid. All the velocity proHles decay algebraically to the ambient zero velocity.%We investigate a viscous flow over a cylinder with stretching and torsional motion.There is an exact solution to the Navier-Stokes equations and there exists a unique solution for all the given values of the flow Reynolds number.The results show that velocity decays faster for a higher Reynolds number and the flow penetrates shallower into the ambient fluid.All the velocity profiles decay algebraically to the ambient zero velocity.Exact solutions of the Navier-Stokes (NS) equations play important roles in the development of fluid mechanics.In the review articles,[1,2] Wang summarized the available exact solutions of the unsteady state and of the steady-state NS equations.Swirl flows have important engineering applications in many fields such as the cyclone for separation of solid,liquid and gas,swirl atomizers,swirl combustion devices,heat transfer enhancement and others.[3,4] A famous example of flows involving rotation or swirl is the rotating disk problem studied by von Karman.[5-8] The flow induced by a stretching boundary is also important in the extrusion processes in plastic and metal industries.[9-11] Crane[12] presented an exact solution of the two-dimensional NS equations for a stretching sheet problem with a closed analytical form.The stretching wall problem was extended by Wang[13]to a three-dimensional setting.The flow between two stretching disks was studied by Fang and Zhang recently.[14] The combined effects of disk stretching and rotation on the von Karman flow was investigated by Fang.[15] The flow inside a channel or a

  16. Study on Phase Change Temperature of PCM Gypsum Panel Applied for External Wall Surface for Summer Insulation%相变石膏板应用于外墙表面夏季隔热的相变温度分析

    Institute of Scientific and Technical Information of China (English)

    张正松; 何嘉鹏; 张博; 张毅; 徐明立

    2012-01-01

    本文提出了将定形相变蓄能石膏板安装在轻质保温墙体外侧取代传统绝热材料,以改善围护结构夏季隔热性能的方法.以南京地区为例,采用Matlab编程比较了定形相变蓄能石膏板和膨胀型聚苯乙烯板在改善轻质围护结构隔热性能方面的差异,并利用焓法模型从相变温度角度对相变蓄能石膏板的使用效果进行了分析.研究结果表明,定形相变蓄能墙体在夏季可以改善建筑物外墙的隔热性能,减少通过围护结构传入室内的热量,相变温度为28℃的蓄能墙体能最大程度缓解夏季室内的空调冷负荷,起到节能效果.%In order to improve the summer insulation performance of lightweight wall, the shape-stabilized phase change material (SSPCM) panel is installed on the exterior surface of the wall, instead of traditional thermal insulation materials. In this paper, taking Nanjing as the research object,the thermal performance differences between SSPCM panel and EPS panel were compared based on the Matlab program. Furthermore,from the perspective of phase change temperature, the effects of SSPCM panel were analyzed using an enthalpy model. The results showed that the SSPCM panel could improve the summer insulation performance of lightweight wall and reduce the heat through the building envelope simultaneously. In additionaL, energy storage wallboard of melting temperature 28 ℃ could decrease the indoor cooling load greatly, and the energy-saving effects were obvious.

  17. 岩棉钢网架板外墙外保温技术性能及应用分析%Analysis on technical properties and application of outer-wall external thermal insulation based on rock wool board with steel network

    Institute of Scientific and Technical Information of China (English)

    杜书廷

    2012-01-01

    对岩棉钢网架板外墙外保温技术的原理、特点、构造及性能要求做了系统的介绍,并对该技术的施工过程和未来应用进行了分析.岩棉钢网架板外墙外保温具有较好的防火性能、墙体的平均传热系数在0.35~0.50 W/(m2·K),绝热效果良好,采用把岩棉板固定于钢网架内,解决了岩棉板下坠的问题,系统的抗拉强度高、整体性和耐久性良好,使用年限可达25年以上.该技术在以后的工程实践中应需注意岩棉板的市场供应、面砖缝隙开裂、岩棉板吸水问题及岩棉板加工和施工中对人的影响等问题.%Technology principle, characteristics, technical structure, performance requirements of outer-wall external thermal insulation based on rock wool board with steel network are introduced, the construction process and application in the future of this technology was analyzed. Outer-wall external thermal insulation based on rock wool board has good fire performance, the average heat transfer coefficient of the wall is 0.35 to 0.50 W/(m2 *K) ,and the insulation effect is good. Fixing the rock wool board in the steel network can address the fall of the rock wool board. The tensile strength, integrity and durability of the system are good, and the service life can be up to 25 years. During the engineering practice in future, special attention should be paid to the market supply of rock wool board, tile gap cracking, rock wool board water absorption problems and the impact of rock wool processing and construction on the people.

  18. Monitoring of Double Stud Wall Moisture Conditions in the Northeast

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation, Westford, MA (United States)

    2015-03-01

    Double-stud walls insulated with cellulose or low-density spray foam can have R-values of 40 or higher. However, double stud walls have a higher risk of interior-sourced condensation moisture damage, when compared with high-R approaches using exterior insulating sheathing.; Moisture conditions in double stud walls were monitored in Zone 5A (Massachusetts); three double stud assemblies were compared.

  19. Generalized Bistability in Origami Cylinders

    Science.gov (United States)

    Reid, Austin; Adda-Bedia, Mokhtar; Lechenault, Frederic

    Origami folded cylinders (origami bellows) have found increasingly sophisticated applications in space flight, medicine, and even experimental nuclear physics. In spite of this interest, a general understanding of the dynamics of an origami folded cylinder has been elusive. By solving the fully constrained behavior of a periodic fundamental origami cell defined by unit vectors, we have found an analytic solution for all possible rigid-face states accessible from a cylindrical Miura-ori pattern. Although an idealized bellows has two rigid-face configurations over a well-defined region, a physical device, limited by nonzero material thickness and forced to balance hinge with plate-bending energy, often cannot stably maintain a stowed configuration. We have identified and measured the parameters which control this emergent bistability, and have demonstrated the ability to fabricate bellows with tunable deployability.

  20. Cylinder components properties, applications, materials

    CERN Document Server

    2016-01-01

    Owing to the ever-increasing requirements to be met by gasoline and diesel engines in terms of CO2 reduction, emission behavior, weight, and service life, a comprehensive understanding of combustion engine components is essential today. It is no longer possible for professionals in automotive engineering to manage without the corresponding expertise, whether they work in the field of design, development, testing, or maintenance. This technical book provides in-depth answers to questions about design, production, and machining of cylinder components. In this second edition, every section has been revised and expanded to include the latest developments in the combustion engine. Content Piston rings Piston pins and piston pin circlips Bearings Connecting rods Crankcase and cylinder liners Target audience Engineers in the field of engine development and maintenanceLecturers and students in the areas of mechanical engineering, engine technology, and vehicle constructionAnyone interested in technology Publisher MAH...

  1. 外墙内保温高层住宅加气混凝土内隔墙周期性裂缝原因分析%Analysis of Periodic Cracks in Aerated Concrete Block Interior Walls of High-Rise Residential Building with Internal Thermal Insulation System

    Institute of Scientific and Technical Information of China (English)

    周建康

    2013-01-01

    The shear wall structure system is adopted by a high-rise residential building, and internal thermal insulation composite system is applied for the exterior walls. After completion of interior walls built with aerated concrete blocks, a large number of cracks appeared in them near the building envelopes. The cracks occurred periodically in next spring or summer after being repaired. Field investigation and theoretical calculation are carried out, and the main causes of cracking are analyzed. Treatment methods are also submitted from the aspects of design and construction, which are available for other similar residential projects.%上海某高层住宅为剪力墙结构,周围墙体采用复合石膏板外墙内保温系统,住宅内隔墙采用加气混凝土砌块.墙体砌筑后在邻近外围结构的部位产生了大量斜裂缝,而且经修补后又会在第二年春夏周期性出现.通过现场调查和理论计算,分析了裂缝产生的主要原因,并从设计和施工两方面提出了预防措施,对类似的住宅工程具有一定的借鉴意义.

  2. Counting Polyominoes on Twisted Cylinders

    OpenAIRE

    Barequet, Gill; Moffie, Micha; Ribó, Ares; Rote, Günter

    2005-01-01

    International audience; We improve the lower bounds on Klarner's constant, which describes the exponential growth rate of the number of polyominoes (connected subsets of grid squares) with a given number of squares. We achieve this by analyzing polyominoes on a different surface, a so-called $\\textit{twisted cylinder}$ by the transfer matrix method. A bijective representation of the "states'' of partial solutions is crucial for allowing a compact representation of the successive iteration vec...

  3. Domain Wall Propagation through Spin Wave Emission

    NARCIS (Netherlands)

    Wang, X.S.; Yan, P.; Shen, Y.H.; Bauer, G.E.W.; Wang, X.R.

    2012-01-01

    We theoretically study field-induced domain wall motion in an electrically insulating ferromagnet with hard- and easy-axis anisotropies. Domain walls can propagate along a dissipationless wire through spin wave emission locked into the known soliton velocity at low fields. In the presence of damping

  4. Design and Analysis of Cylinder and Cylinder head of 4-stroke SI Engine for weight reduction

    Directory of Open Access Journals (Sweden)

    Ravindra R. Navthar

    2012-03-01

    Full Text Available The present paper deals with design of cylinder & cylinder head with air cooling system for 4 strokes 4 cylinder SI engine. The main objective of design is to reduce weight to power ratio & will result in producing high specific power. The authors have proposed preliminary design cylinder & cylinder head of a horizontallyopposed SI engine, which develops 120 BHP and posses the maximum rotational speed of 6000rpm. Four stroke opposed engine is inherently well balanced due to opposite location of moving masses and also it provides efficient air cooling. For the requirement of weight reduction the material selected for design of cylinder and cylinder head is Aluminum alloy that is LM-13. The cylinder bore coating using NIKASIL coating was done to improve strength of cylinder with minimum weight..

  5. Structure Change of the Insulating Composite

    Directory of Open Access Journals (Sweden)

    Vaclav Mentlik

    2008-01-01

    Full Text Available Modern power electric drives brought advantages in induction motor control. In the same time appeared problems with high frequency square waveform voltage (pulse stress produced by the voltage converters. Voltage converters produce repetitive pulses with high level of voltage rise fronts (slew rates. Rise fronts attained values of up to tens kilovolts per microsecond and voltage pulse repetition frequency up to some tens of kilohertz. This technology is an advantage for a drive control. Significant is the impact of these voltage waveforms on the motor insulations. Degradation of the main wall insulation can reduce the reliability of the electric motor and whole drive. In this paper is discussed one possible solution. The promising modification in the insulation material structure is presented in the paper.

  6. Strongly Correlated Topological Insulators

    Science.gov (United States)

    2016-02-03

    Research Triangle Park , NC 27709-2211 Condensed Matter, Topological Phases of Matter REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER(S...Strongly Correlated Topological Insulators In the past year, the grant was used for work in the field of topological phases, with emphasis on finding...surface of topological insulators. In the past 3 years, we have started a new direction, that of fractional topological insulators. These are materials

  7. Lattice Boltzmann simulation of surface radiation and natural convection in a square cavity with an inner cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Mezrhab, Ahmed; Moussaoui, M A [Laboratoire de Mecanique and Energetique, Departement de Physique, Faculte des Sciences, Universite Mohamed 1, Oujda (Morocco); Naji, H [Universite des Sciences et Technologies de Lille/Polytech' Lille/LML UMR 8107, F-59655 Villeneuve d' Ascq Cedex (France)], E-mail: mezrhab@fso.ump.ma

    2008-06-07

    A numerical study is carried out for conjugate natural convection-surface radiation heat transfer from a heated circular cylinder enclosed in a square cavity. A hybrid scheme with lattice Boltzmann for fluid velocity variables and finite difference for the temperature is used. The vertical walls of the enclosure are cooled with a uniform temperature while the others are adiabatic. Effects of the Rayleigh number, size and location of the heated cylinder and surface emissivities are investigated numerically. The results are reported in terms of isotherms, streamlines and the average Nusselt number. It is found that (i) the radiation exchange standardizes the temperature inside the cavity and produces an increase in the heat transfer, particularly at large Ra, (ii) the heat transfer enhances with increasing cylinder size and/or surface emissivity and (iii) the maximum rate of heat transfer occurs when the cylinder is located at the horizontal median close to the vertical wall.

  8. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Rige, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover the valves failed and UF{sub 6} was released. The remaining cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  9. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Ridge, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} x 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover, the valves failed and UF{sub 6} was released. The remaining 6 cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  10. Detection of cylinder pressure in diesel engines using cylinder head vibration and time series methods

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper investigates the vibration characteristics of diesel engine cylinder heads by means of the time series method.With the concept of "Assumed System", the vibration transfer function of real cylinder head structures is established using the autoregressive-moving average models (ARMA models) of cylinder head surface vibration signals.Then this transfer function is successfully used to reconstruct the gas pressure trace inside the cylinder from measured cylinder head vibration signals.This offers an effective means for diesel engine cylinder pressure detection and condition monitoring.

  11. Composite Flexible Blanket Insulation

    Science.gov (United States)

    Kourtides, Demetrius A. (Inventor); Pitts, William C. (Inventor); Goldstein, Howard E. (Inventor); Sawko, Paul M. (Inventor)

    1991-01-01

    Composite flexible multilayer insulation systems (MLI) were evaluated for thermal performance and compared with the currently used fibrous silica (baseline) insulation system. The systems described are multilayer insulations consisting of alternating layers of metal foil and scrim ceramic cloth or vacuum metallized polymeric films quilted together using ceramic thread. A silicon carbide thread for use in the quilting and the method of making it are also described. These systems are useful in providing lightweight insulation for a variety of uses, particularly on the surface of aerospace vehicles subject to very high temperatures during flight.

  12. Plasmonics in Topological Insulators

    Directory of Open Access Journals (Sweden)

    Yi-Ping Lai

    2014-04-01

    Full Text Available With strong spin-orbit coupling, topological insulators have an insulating bulk state, characterized by a band gap, and a conducting surface state, characterized by a Dirac cone. Plasmons in topological insulators show high frequency-tunability in the mid-infrared and terahertz spectral regions with transverse spin oscillations, also called “spin-plasmons”. This paper presents a discussion and review of the developments in this field from the fundamental theory of plasmons in bulk, thin-film, and surface-magnetized topological insulators to the techniques of plasmon excitation and future applications.

  13. 夏热冬冷地区外墙保温系统技术发展趋势探讨%Discussion on the Development Trend of External Wall Insulation System Technology in Area with Hot Summer and Cold Winter

    Institute of Scientific and Technical Information of China (English)

    沈敏奇

    2014-01-01

    当今,节能建筑已成为项目工程建筑中一个重要的组成部分。对结构外围护性能进行提高与改善、对外墙保温系统设计和构造进行优化,是节能建筑的重点工程。%Nowadays, building energy conservation has beco-me an important part of project construction. To enhance and improve envelope performance, and to improve optimize the external wal insulation system design and structure is a key project in building energy saving.

  14. Conducting Wall Hall Thrusters

    Science.gov (United States)

    Goebel, Dan M.; Hofer, Richard R.; Mikellides, Ioannis G.; Katz, Ira; Polk, James E.; Dotson, Brandon

    2013-01-01

    A unique configuration of the magnetic field near the wall of Hall thrusters, called Magnetic Shielding, has recently demonstrated the ability to significantly reduce the erosion of the boron nitride (BN) walls and extend the life of Hall thrusters by orders of magnitude. The ability of magnetic shielding to minimize interactions between the plasma and the discharge chamber walls has for the first time enabled the replacement of insulating walls with conducting materials without loss in thruster performance. The boron nitride rings in the 6 kW H6 Hall thruster were replaced with graphite that self-biased to near the anode potential. The thruster efficiency remained over 60% (within two percent of the baseline BN configuration) with a small decrease in thrust and increase in Isp typical of magnetically shielded Hall thrusters. The graphite wall temperatures decreased significantly compared to both shielded and unshielded BN configurations, leading to the potential for higher power operation. Eliminating ceramic walls makes it simpler and less expensive to fabricate a thruster to survive launch loads, and the graphite discharge chamber radiates more efficiently which increases the power capability of the thruster compared to conventional Hall thruster designs.

  15. Cladding Attachment Over Thick Exterior Insulating Sheathing

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P.; Eng, P.; Lepage, R.

    2014-01-01

    The addition of insulation to the exterior of buildings is an effective means of increasing the thermal resistance of both wood framed walls as well as mass masonry wall assemblies. For thick layers of exterior insulation (levels greater than 1.5 inches), the use of wood furring strips attached through the insulation back to the structure has been used by many contractors and designers as a means to provide a convenient cladding attachment location (Straube and Smegal 2009, Pettit 2009, Joyce 2009, Ueno 2010). The research presented in this report is intended to help develop a better understanding of the system mechanics involved and the potential for environmental exposure induced movement between the furring strip and the framing. BSC sought to address the following research questions: 1. What are the relative roles of the mechanisms and the magnitudes of the force that influence the vertical displacement resistance of the system? 2. Can the capacity at a specified deflection be reliably calculated using mechanics based equations? 3. What are the impacts of environmental exposure on the vertical displacement of furring strips attached directly through insulation back to a wood structure?

  16. Cladding Attachment Over Thick Exterior Insulating Sheathing

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P. [Building Science Corporation, Somerville, MA (United States); Eng, P. [Building Science Corporation, Somerville, MA (United States); Lepage, R. [Building Science Corporation, Somerville, MA (United States)

    2014-01-01

    The addition of insulation to the exterior of buildings is an effective means of increasing the thermal resistance of both wood framed walls as well as mass masonry wall assemblies. For thick layers of exterior insulation (levels greater than 1.5 inches), the use of wood furring strips attached through the insulation back to the structure has been used by many contractors and designers as a means to provide a convenient cladding attachment location (Straube and Smegal 2009, Pettit 2009, Joyce 2009, Ueno 2010). The research presented in this report is intended to help develop a better understanding of the system mechanics involved and the potential for environmental exposure induced movement between the furring strip and the framing. BSC sought to address the following research questions: 1.What are the relative roles of the mechanisms and the magnitudes of the force that influence the vertical displacement resistance of the system? 2.Can the capacity at a specified deflection be reliably calculated using mechanics based equations? 3.What are the impacts of environmental exposure on the vertical displacement of furring strips attached directly through insulation back to a wood structure?

  17. Insulation systems of the building construtions

    Directory of Open Access Journals (Sweden)

    Rumiantcev Boris

    2016-01-01

    Full Text Available Constructions of the exterior insulation and decoration combines materials of different functionality and constructive solutions allows to these materials to demonstrate their efficiency to the great extent. Fire safety of buildings is mandatory requirement for building systems. Some insulating material may belong to the group of combustible, but their use in structures so as to minimize the risk of fire. On the other hand, there are special designs, in which non-flammable insulation acts as a flame retardant barrier. In the article carried systematization of construction systems used in the flat and pitched roof during the insulation and wall covering and facades. Taking into account the experience of leading firms were considered the application features of using exterior finish systems: construction solutions, requirements for materials and recommendations about the installation these systems.The article deals with the construction ventilated roofing system of two types: flat roof and pitched roof seam. In the first case, the ventilation system is created using milled insulation boards in the second - by a ventilated gap. In both cases the natural convection of air in the air cavities. Ensuring operational stability insulation is laid on the stages of production of heat-insulating materials. It is important: firstly responsible execution of all process operations associated with providing regulatory properties of materials and secondly, the performance of additional operations associated with the produc-tion of materials, working in a specific design. An example of a material whose properties can modify for a particular application, are milled mineral wool (with air channels for systems of ventilated flat roof.

  18. Fatigue Tests with Densit Cylinders - D4

    DEFF Research Database (Denmark)

    Ellegaard, Peter

    This report contains descriptions and results of a series of fatigue tests performed during the autumn of 2005 at the Stuctural Research Laboratory, Aalborg University. Cylinders with a diameter of 45 mm and a height of 90 mm were used as test specimens; the material was Densit Ducorit D4. Four...... cylinders were tested statically under compression and the rest of the cylinders (30) were tested under fatigue conditions with a load varying sinusoidally....

  19. Rarita-Schwinger Type operators on Cylinders

    OpenAIRE

    2011-01-01

    Here we define Rarita-Schwinger operators on cylinders and construct their fundamental solutions. Further the fundamental solutions to the cylindrical Rarita-Schwinger type operators are achieved by applying translation groups. In turn, a Borel-Pompeiu Formula, Cauchy Integral Formula and a Cauchy Transform are presented for the cylinders. Moreover we show a construction of a number of conformally inequivalent spinor bundles on these cylinders. Again we construct Rarita-Schwinger operators an...

  20. Two interacting cylinders in cross flow

    Science.gov (United States)

    Alam, Md. Mahbub; Meyer, J. P.

    2011-11-01

    Cylindrical structures in a group are frequently seen on land and in the ocean. Mutual flow interaction between the structures makes the wake very excited or tranquil depending on the spacing between the structures. The excited wake-enhancing forces in some cases cause a catastrophic failure of the structures. This paper presents results of an experimental investigation of Strouhal number (St), time-mean, and fluctuating forces on, and flow structures around, two identical circular cylinders at stagger angle α = 0 °-180 ° and gap-spacing ratio T/D=0.1-5, where T is the gap width between the cylinders, and D is the diameter of a cylinder. While forces were measured using a load cell, St was from spectral analysis of fluctuating pressures measured on the side surfaces of the cylinders. A flow visualization test was conducted to observe flow structures around the cylinders. Based on forces, St, and flow structures, 19 distinct flow categories in the ranges of α and T/D investigated are observed, including one quadristable flow, three kinds of tristable flows, and four kinds of bistable flows. The quadristable, tristable, and bistable flows ensue from instabilities of the gap flow, shear layers, vortices, separation bubbles, and wakes, engendering a strong jump or drop in forces and St of the cylinders. The two cylinders interact with each other in six different mechanisms, namely interaction between boundary layer and cylinder, shear layer or wake and cylinder, shear layer and shear layer, vortex and cylinder, vortex and shear layer, and vortex and vortex. While the interaction between vortex and cylinder results in a very high fluctuating drag, that between vortex and shear layer results in a high fluctuating lift. On the other hand, the interaction between shear layer or wake and cylinder weakens mean and fluctuating forces and flow unsteadiness. A mutual discussion of forces, St, and flow structures is presented in this paper.

  1. Cylinder valve packing nut studies

    Energy Technology Data Exchange (ETDEWEB)

    Blue, S.C. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

  2. Quantum Mechanics on the cylinder

    CERN Document Server

    González, J A; Tosiek, J

    2003-01-01

    A new approach to deformation quantization on the cylinder considered as phase space is presented. The method is based on the standard Moyal formalism for R^2 adapted to (S^1 x R) by the Weil--Brezin--Zak transformation. The results are compared with other solutions of this problem presented by Kasperkovitz and Peev (Ann. Phys. vol. 230, 21 (1994)0 and by Plebanski and collaborators (Acta Phys. Pol. vol. B 31}, 561 (2000)). The equivalence of these three methods is proved.

  3. Effect of shear on duct wall impedance.

    Science.gov (United States)

    Goldstein, M.; Rice, E.

    1973-01-01

    The solution to the equation governing the propagation of sound in a uniform shear layer is expressed in terms of parabolic cylinder functions. This result is used to develop a closed-form solution for acoustic wall impedance which accounts for both the duct liner and the presence of a boundary layer in the duct. The effective wall impedance can then be used as the boundary condition for the much simpler problem of sound propagation in uniform flow.

  4. INTERACTION OF A FLOATING ELLIPTIC CYLINDER WITH A VIBRATING CIRCULAR CYLINDER

    Institute of Scientific and Technical Information of China (English)

    SUN Ren; CHWANG Allen T.

    2006-01-01

    The nonlinear hydrodynamic interaction between a floating elliptic cylinder and a vibrating circular cylinder immersed in an infinite fluid was investigated. By taking the added masses of the two-cylinder system into account, the dynamical equations of motion were formulated from the Lagrange equations of motion. The dynamical behaviors of these two cylinders were analyzed numerically for some typical situations, and the results show that the presence of a vibrating circular cylinder has a significant influence on the planar motion of a floating elliptic cylinder. The hydrodynamic interaction between them results in complicated nonlinear behaviors of the floating cylinder. It is found that oscillatory motion of the elliptic cylinder takes place in response to the vibrating mode of the circular one.

  5. Translucent insulating building envelope

    DEFF Research Database (Denmark)

    Rahbek, Jens Eg

    1997-01-01

    A new type of translucent insulating material has been tested. This material is made of Celulose-Acetat and have a honey-comb structure. The material has a high solar transmittance and is highly insulating. The material is relatively cheap to produce. Danish Title: Translucent isolerende klimaskærm....

  6. Translucent insulating building envelope

    DEFF Research Database (Denmark)

    Rahbek, Jens Eg

    1997-01-01

    A new type of translucent insulating material has been tested. This material is made of Celulose-Acetat and have a honey-comb structure. The material has a high solar transmittance and is highly insulating. The material is relatively cheap to produce. Danish Title: Translucent isolerende klimaskærm....

  7. Inner cylinder of the CMS vacuum tank.

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    The vacuum tank of the CMS magnet system consists of inner and outer stainless-steel cylinders and houses the superconducting coil. The inner cylinder contains all the barrel sub-detectors, which it supports via a system of horizontal rails. The cylinder is pictured here in the vertical position on a yellow platform mounted on the ferris-wheel support structure. This will allow it to be pivoted and inserted into the outer cylinder already attached to the innermost ring of the barrel yoke.

  8. Fire exposure of empty 30B cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Ziehlke, K.T. [MJB Technical Associates, Inc., Knoxville, TN (United States)

    1991-12-31

    Cylinders for UF{sub 6} handling, transport, and storage are designed and built as unfired pressure vessels under ASME Boiler and Pressure Vessel Code criteria and standards. They are normally filled and emptied while UF{sub 6} is in its liquid phase. Transport cylinders such as the Model 30B are designed for service at 200 psi and 250{degrees}F, to sustain the process conditions which prevail during filling or emptying operations. While in transport, however, at ambient temperature the UF{sub 6} is solid, and the cylinder interior is well below atmospheric pressure. When the cylinders contain isotopically enriched product (above 1.0 percent U-235), they are transported in protective overpacks which function to guard the cylinders and their contents against thermal or mechanical damage in the event of possible transport accidents. Two bare Model 30B cylinders were accidentally exposed to a storage warehouse fire in which a considerable amount of damage was sustained by stored materials and the building structure, as well as by the cylinder valves and valve protectors. The cylinders were about six years old, and had been cleaned, inspected, hydrotested, and re-certified for service, but were still empty at the time of the fire. The privately-owned cylinders were transferred to DOE for testing and evaluation of the fire damage.

  9. Overseas shipments of 48Y cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, R.T.; Furlan, A.S. [Cameco Corp., Port Hope, Ontario (Canada)

    1991-12-31

    This paper describes experiences with two incidents of overseas shipments of uranium hexafluoride (UF{sub 6}) cylinders. The first incident involved nine empty UF{sub 6} cylinders in enclosed sea containers. Three UF{sub 6} cylinders broke free from their tie-downs and damaged and contaminated several sea containers. This paper describes briefly how decontamination was carried out. The second incident involved a shipment of 14 full UF{sub 6} cylinders. Although the incident did not cause an accident, the potential hazard was significant. The investigation of the cause of the near accident is recounted. Recommendations to alleviate future similar incidents for both cases are presented.

  10. Optimization and improvement of Halbach cylinder design

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Bahl, Christian Robert Haffenden; Smith, Anders;

    2008-01-01

    that this parameter was optimal for long Halbach cylinders with small rex. Using the previously mentioned additional blocks of magnets can improve the parameter by as much as 15% as well as improve the homogeneity of the field in the cylinder bore. ©2008 American Institute of Physics......In this paper we describe the results of a parameter survey of a 16 segmented Halbach cylinder in three dimensions in which the parameters internal radius, rin, external radius, rex, and length, L, have been varied. Optimal values of rex and L were found for a Halbach cylinder with the least...

  11. Problems with plastered external heat insulation. Probleme mit verputzter Aussenwaermedaemmung

    Energy Technology Data Exchange (ETDEWEB)

    Epple, H.; Foglia, A.; Preisig, H.; Pfefferkorn, J.

    1984-01-01

    Concerning execution, maintenance and service life, walls with plastered external heat insulation constitute an economic method. Owing to experience gained with plastered external heat insulation, it is possible today to provide reliable information on requirements made on ground material and operational execution. The author intends to contribute to a prevention of defects by giving concise examples. A survey on different types of external heat insulation is followed by a treatment of the problem areas of roof-edge connection, base end under ground, modernization of old buildings and cracks in plaster. Principal statements are made concerning steam diffusion, planning, materials and execution.

  12. Sound Insulation between Dwellings

    DEFF Research Database (Denmark)

    Rasmussen, Birgit

    2011-01-01

    Regulatory sound insulation requirements for dwellings exist in more than 30 countries in Europe. In some countries, requirements have existed since the 1950s. Findings from comparative studies show that sound insulation descriptors and requirements represent a high degree of diversity...... and initiate – where needed – improvement of sound insulation of new and existing dwellings in Europe to the benefit of the inhabitants and the society. A European COST Action TU0901 "Integrating and Harmonizing Sound Insulation Aspects in Sustainable Urban Housing Constructions", has been established and runs...... 2009-2013. The main objectives of TU0901 are to prepare proposals for harmonized sound insulation descriptors and for a European sound classification scheme with a number of quality classes for dwellings. Findings from the studies provide input for the discussions in COST TU0901. Data collected from 24...

  13. Sound insulation between dwellings

    DEFF Research Database (Denmark)

    Rasmussen, Birgit

    2011-01-01

    Regulatory sound insulation requirements for dwellings exist in more than 30 countries in Europe. In some countries, requirements have existed since the 1950s. Findings from comparative studies show that sound insulation descriptors and requirements represent a high degree of diversity...... and initiate – where needed – improvement of sound insulation of new and existing dwellings in Europe to the benefit of the inhabitants and the society. A European COST Action TU0901 "Integrating and Harmonizing Sound Insulation Aspects in Sustainable Urban Housing Constructions", has been established and runs...... 2009-2013. The main objectives of TU0901 are to prepare proposals for harmonized sound insulation descriptors and for a European sound classification scheme with a number of quality classes for dwellings. Findings from the studies provide input for the discussions in COST TU0901. Data collected from 24...

  14. RANS-VOF Solver for Solitary Wave Run-up on A Circular Cylinder

    Institute of Scientific and Technical Information of China (English)

    曹洪建; 万德成

    2015-01-01

    Simulation of solitary wave run-up on a vertical circular cylinder is carried out in a viscous numerical wave tank developed based on the open source codes OpenFOAM. An incompressible two-phase flow solver naoe-FOAM-SJTU is used to solve the Reynolds-Averaged Navier–Stokes (RANS) equations with the SST k-wturbulence model. The PISO algorithm is utilized for the pressure-velocity coupling. The air-water interface is captured via Volume of Fluid (VOF) technique. The present numerical model is validated by simulating the solitary wave run-up and reflected against a vertical wall, and solitary wave run-up on a vertical circular cylinder. Comparisons between numerical results and available experimental data show satisfactory agreement. Furthermore, simulations are carried out to study the solitary wave run-up on the cylinder with different incident wave height H and different cylinder radius a. The relationships of the wave run-up height with the incident wave height H, cylinder radius a are analyzed. The evolutions of the scattering free surface and vortex shedding are also presented to give a better understanding of the process of nonlinear wave-cylinder interaction.

  15. Numerical simulation and experiment on split tungsten carbide cylinder of high pressure apparatus.

    Science.gov (United States)

    Yang, Yunfei; Li, Mingzhe; Liu, Zhiwei; Wang, Bolong

    2015-12-01

    A new high pressure device with a split cylinder was investigated on the basis of the belt-type apparatus. The belt-type die is subjected to excessive tangential tensile stress and the tungsten carbide cylinder is easily damaged in the running process. Taking into account the operating conditions and material properties of the tungsten carbide cylinder, it is divided into 6 blocks to eliminate the tangential tensile stress. We studied two forms of the split type: radial split and tangential split. Simulation results indicate that the split cylinder has more uniform stress distribution and smaller equivalent stress compared with the belt-type cylinder. The inner wall of the tangential split cylinder is in the situation that compressive stress is distributed in the axial, radial, and tangential directions. It is similar to the condition of hydrostatic pressure, and it is the best condition for tungsten carbide materials. The experimental results also verify that the tangential split die can bear the highest chamber pressure. Therefore, the tangential split structure can increase the pressure bearing capacity significantly.

  16. Flow control behind a circular cylinder via a porous cylinder in deep water

    Directory of Open Access Journals (Sweden)

    Akilli H.

    2013-04-01

    Full Text Available In this present work, the effects of surrounding outer porous cylinder on vortex structure downstream of a circular inner cylinder are investigated experimentally in deep water flow. The porosity of outer cylinder were selected as β = 0.4, 0.5, 0.6, 0.65, 0.7, 0.75, 0.8 and 0.85. Porosity is defined as the ratio of the gap area on the body to the whole body surface area. The ratio of outer cylinder diameter to inner cylinder diameter, Do/Di was selected as 2.0, i.e. the inner cylinder diameter is Di = 30 mm where the outer cylinder diameter is Do = 60 mm. All experiments were carried out above a platform. The water height between the base of the platform and the free surface was adjusted as 340 mm. Free stream velocity is U = 156 mm/s, which corresponds to the Reynolds number of Rei = 5,000 based on the inner cylinder diameter. It has been observed that the outer porous cylinders have influence on the attenuation of vortex shedding in the wake region for all porosities. The turbulent intensity of the flow is reduced at least 45% by the presence of outer porous cylinder compared to the bare cylinder case. The porosities β = 0.4 and 0.5 are most suitable cases to control the flow downstream of the circular cylinder.

  17. ECOLOGICAL SOLUTIONS FOR LOW ENERGY BUILDING WALLS

    Directory of Open Access Journals (Sweden)

    Camelia COŞEREANU

    2012-03-01

    Full Text Available The paper presents constructive solutions for thermal insulation of the building walls, using recycled and biodegradable materials. The thermal insulatingcomposite materials are made of textile fibers obtained from waste of the textile industrial sector, wood fibers and wood chips from the wood industrial sector and mineral materials as binders: gypsum, cement, ceramic dust or industrial clay. For each type of compositematerial, the thermal conductivity coefficient has been determined and compared. The final results of thermal insulation of the walls were obtained after using the software of analyzing the thermal insulation property of various proposed composites. The main advantage of the proposed materials is their ecological characteristic compared with classical structures used today in buildings thermal insulation.

  18. Chemical aspects of cylinder corrosion and a scenario for hole development

    Energy Technology Data Exchange (ETDEWEB)

    Barber, E.J. [Martin Marietta Energy Systems, Oak Ridge, TN (United States)

    1991-12-31

    In June 1990, two cylinders in the depleted UF{sub 6} cylinder storage yards at Portsmouth were discovered to have holes in their walls at the valve-end stiffening ring at a point below the level of the gas-solid interface of the UF{sub 6}. The cylinder with the larger hole, which extended under the stiffening ring, was stacked in a top row 13 years ago. The cylinder with the smaller hole had been stacked in a bottom row 4 years ago. The lifting lugs of the adjacent cylinders pointed directly at the holes. A Cylinder Investigating Committee was appointed to determine the cause or causes of the holes and to assess the implications of these findings. This report contains a listing of the chemically related facts established by the Investigating Committee with the cooperation of the Operations and Technical Support Divisions at the Portsmouth Gaseous Diffusion Plant, the scenario developed to explain these findings and some implications of this scenario. In summary, the interrelated reactions of water, solid UF{sub 6} and iron presented by R. L. Ritter are used to develop a scenario which explains the observations and deductions made during the investigation. The chemical processes are intimately related to the course of the last three of the four stages of hole development. A simple model is proposed which permits semiquantitative prediction of such information as the HF loss rates as a function of time, the rate of hole enlargement, the time to hydrolyze a cylinder of UF{sub 6} and the approximate size of the hole. The scenario suggests that the environmental consequences associated with a developing hole in a depleted UF{sub 6} cylinder are minimal for the first several years but will become significant if too many years pass before detection. The overall environmental picture is presented in more detail elsewhere.

  19. A Monte Carlo simulation of the packing and segregation of spheres in cylinders

    Directory of Open Access Journals (Sweden)

    C. R. A. ABREU

    1999-12-01

    Full Text Available In this work, the Monte Carlo method (MC was extended to simulate the packing and segregation of particles subjected to a gravitational field and confined inside rigid walls. The method was used in systems containing spheres inside cylinders. The calculation of void fraction profiles in both the axial and radial directions was formulated, and some results are presented. In agreement with experimental data, the simulations show that the packed beds present structural ordering near the cylindrical walls up to a distance of about 4 particle diameters. The simulations also indicate that the presence of the cylindrical wall does not seem to have a strong effect on the gravitational segregation phenomenon.

  20. Acoustical properties of some modern partitioning glass walls systems – case study

    Directory of Open Access Journals (Sweden)

    Ioana-Mihaela ALEXE

    2014-04-01

    Full Text Available The case study presents the results of laboratory measurements carried out for the determination of airborne sound insulation properties for various modern partition glass walls systems. The analyzed partition glass walls were made with structures of aluminum profiles and with sheets of glazed materials. Laboratory measurements for determining the airborne sound insulation of walls were performed in the airborne sound insulation stand of Building Acoustics Laboratory of NRDI URBAN INCERC, INCERC Bucharest Branch, in accordance with EN ISO 10140- 2 "Acoustics. Laboratory measurement of sound insulation of building elements. Part 2: Measurement of airborne sound insulation". Measurement results are presented as airborne sound insulation indexes, Rw, and in graph form in the range of frequency 100 ... 3150 Hz. Rating of sound insulation of the walls was made in accordance with EN ISO 717-1 "Acoustics. Rating of sound insulation in buildings and of building elements. Part 1: Airborne sound insulation". After analyzing the results of the measurements, conclusions were drawn regarding the influence of partition glass walls structure on sound insulation properties, both on airborne sound insulation index, Rw, and on graphical results in the frequency range.

  1. A Convenient Storage Rack for Graduated Cylinders

    Science.gov (United States)

    Love, Brian

    2004-01-01

    An attempt is made to find a solution to the occasional problem of a need for storing large numbers of graduated cylinders in many teaching and research laboratories. A design, which involves the creation of a series of parallel channels that are used to suspend inverted graduated cylinders by their bases, is proposed.

  2. Optimization and improvement of Halbach cylinder design

    CERN Document Server

    Bjørk, R; Smith, A; Pryds, N

    2014-01-01

    In this paper we describe the results of a parameter survey of a 16 segmented Halbach cylinder in three dimensions in which the parameters internal radius, $r_{\\mathrm{\\scriptsize{in}}}$, external radius, $r_{\\mathrm{\\scriptsize{ex}}}$, and length, $L$, have been varied. Optimal values of $r_{\\mathrm{\\scriptsize{ex}}}$ and $L$ were found for a Halbach cylinder with the least possible volume of magnets with a given mean flux density in the cylinder bore. The volume of the cylinder bore could also be significantly increase by only slightly increasing the volume of the magnets, for a fixed mean flux density. Placing additional blocks of magnets on the end faces of the Halbach cylinder also improved the mean flux density in the cylinder bore, especially so for short Halbach cylinders with large $r_{\\mathrm{\\scriptsize{ex}}}$. Moreover magnetic cooling as an application for Halbach cylinders was considered. A magnetic cooling quality parameter, $\\Lambda_{\\mathrm{cool}}$, was introduced and results showed that this...

  3. Microsphere Insulation Panels

    Science.gov (United States)

    Mohling, R.; Allen, M.; Baumgartner, R.

    2006-01-01

    Microsphere insulation panels (MIPs) have been developed as lightweight, longlasting replacements for the foam and vacuum-jacketed systems heretofore used for thermally insulating cryogenic vessels and transfer ducts. The microsphere core material of a typical MIP consists of hollow glass bubbles, which have a combination of advantageous mechanical, chemical, and thermal-insulation properties heretofore available only separately in different materials. In particular, a core filling of glass microspheres has high crush strength and low density, is noncombustible, and performs well in soft vacuum.

  4. Insulation fact sheet

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-08-01

    Electricity bills, oil bills, gas bills - all homeowners pay for one or more of these utilities, and wish they paid less. Often many of us do not really know how to control or reduce our utility bills. We resign ourselves to high bills because we think that is the price we have to pay for a comfortable home. We encourage our children to turn off the lights and appliances, but may not recognize the benefits of insulating the attic. This publication provides facts relative to home insulation. It discusses where to insulate, what products to use, the decision making process, installation options, and sources of additional information.

  5. NUMERICAL STUDY OF NATURAL CONVECTION FROM TWO PARALLEL HORIZONTAL CYLINDERS ENCLOSED BY CIRCULAR CYLINDER

    Directory of Open Access Journals (Sweden)

    Mahmood Husain Ali

    2013-05-01

    Full Text Available In this paper, numerical solution is presented for the steady state, two dimensional natural convection heat transfer from two parallel horizontal cylinders enclosed by circular cylinder. The inner cylinders are heated and maintained at constant surface temperature, while the outer cylinder is cooled at constant surface temperature. Boundary fitted coordinate system is used to solve governing equations. The vorticity-stream function and energy equations is solved using explicit finite deference method and stream function equation solved by successive iteration method. (20Deferent cases are studied cover rang of Rayleigh number from (1,000 to (25,000 based on the inner cylinder diameter. These cases study the effect of the  varying inner cylinders position horizontally and vertically within outer cylinder on the heat transfer and buoyancy that causes the flow. Outputs are displayed in terms of streamline, isothermal contours and local and average Nusselt number. The results showed that the position of the inner cylinders highly affects the heat transfer and flow movements in the gap. At low Rayleigh numbers the average Nusselt number increases with increase of horizontal distance between inner cylinders but the state is reversed at high Rayleigh numbers, while the average Nusselt number is increases with inner cylinder moving down at all Rayleigh numbers. The optimal position of inner cylinders for maximum and minimum heat transfer is located at each Rayleigh number so can be employed in isolation process or cooling process.

  6. Quantum walk on a cylinder

    CERN Document Server

    Bru, Luis A; Di Molfetta, Giuseppe; Pérez, Armando; Roldán, Eugenio; Silva, Fernando

    2016-01-01

    We consider the 2D alternate quantum walk on a cylinder. We concentrate on the study of the motion along the open dimension, in the spirit of looking at the closed coordinate as a small or "hidden" extra dimension. If one starts from localized initial conditions on the lattice, the dynamics of the quantum walk that is obtained after tracing out the small dimension shows the contribution of several components, which can be understood from the study of the dispersion relations for this problem. In fact, these components originate from the contribution of the possible values of the quasi-momentum in the closed dimension. In the continuous space-time limit, the different components manifest as a set of Dirac equations, with each quasi-momentum providing the value of the corresponding mass. We briefly discuss the possible link of these ideas to the simulation of high energy physical theories that include extra dimensions.

  7. STATUS OF THE DIELECTRIC WALL ACCELERATOR

    Energy Technology Data Exchange (ETDEWEB)

    Caporaso, G J; Chen, Y; Sampayan, S; Akana, G; Anaya, R; Blackfield, D; Carroll, J; Cook, E; Falabella, S; Guethlein, G; Harris, J; Hawkins, S; Hickman, B; Holmes, C; Horner, A; Nelson, S; Paul, A; Pearson, D; Poole, B; Richardson, R; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J; Weir, J

    2009-04-22

    The dielectric wall accelerator (DWA) system being developed at the Lawrence Livermore National Laboratory (LLNL) uses fast switched high voltage transmission lines to generate pulsed electric fields on the inside of a high gradient insulating (HGI) acceleration tube. High electric field gradients are achieved by the use of alternating insulators and conductors and short pulse times. The system is capable of accelerating any charge to mass ratio particle. Applications of high gradient proton and electron versions of this accelerator will be discussed. The status of the developmental new technologies that make the compact system possible will be reviewed. These include, high gradient vacuum insulators, solid dielectric materials, photoconductive switches and compact proton sources.

  8. Influence of Method of Bricklaying with Trowel on Thermal Insulation Property of Hollow Brick Wall%传热方向对空心砌块墙体热工性能的影响

    Institute of Scientific and Technical Information of China (English)

    肖婷; 魏玲

    2014-01-01

    通过对砌块单元的模拟值与实验值的比较,确定了模拟结果的可信度,运用数值计算的方法模拟了24种不同孔洞结构的240 mm×115 mm×90 mm粉煤灰小型空心砌块的耦合传热过程,得出单个空心砌块的当量导热系数值。模拟中考虑沿着砌块长度及宽度方向传热对当量导热系数的影响。结果表明:沿着传热垂直方向增加孔数减弱了砌块的保温隔热效果,沿着传热平行方向增加孔数增强了砌块的保温隔热性能。模拟的结果对粉煤灰小型空心砌块的结构选型、优化设计和建筑的节能与节材具有重要意义。%The reliability of simulation is confirmed by the comparison of the experimental value and simulation value of block unit. The coupled heat transportation process of 240 mm×115 mm×90 mm fly-ash small-sized hollow brick with 24 kinds of configurations with different holes number and arrays was simu-lated, and equivalent thermal conductivity (ETC) of single hollow brick was obtained. Heat transfer along length and width direction to the hollow block is considered in the simulation. The results showed that:with the increase of the holes number in vertical direction of heat transfer, the effect of thermal insulation on hollow bricks is weakened; but with the increase of the holes number in parallel direction of heat trans-fer, the effect of thermal insulation on hollow bricks is enhanced. The results of simulation have signifi-cance for structural form selection, optimal design and energy conservation and materials saving for build-ings.

  9. Locating Ectopic Foci on a Cylinder

    Science.gov (United States)

    Kuklik, Pawel; Zebrowski, Jan J.

    2003-07-01

    Arrhythmia is a condition in which an additional ectopic pacemaker is present in the tissue of the heart. Localization of ectopic foci is essential for successful radio-frequency ablation, an important surgical way of treating arrhythmia. In one of the possible mechanisms, arrhythmia induced by an ectopic foci located in one of the main blood vessels leading out or onto the heart. The therapeutic procedure in this case is usually ablation of the whole junction of the blood vessel with heart wall. In this way, whatever excitation occurs inside the vessel, it cannot penetrate the ventricles perturbing their contraction cycle. Such an ablation procedure is long and burdened with the risk of the perforation. A more safe method would involve the localization of the source of the excitation (i.e. the ectopic foci) and its ablation. The methods used in cardiology at present involve complicated localization systems and are time-consuming with the patient spending a long time on the operating table. Recently, Hall and Glass have developed numerical methods which allow to quickly to model the localization of the ectopic foci in a flat, square sample of an inhomogeneous medium. Here, we demonstrate an extension of this model for the case of a cylinder containing an ectopic foci, that can be a model of a blood vessel with the source of the ectopic beat inside it. Three methods of localization are implemented. Standard electrodes containing several active tips are used to stimulate the medium locally and locate the foci judging from the reaction of the system. The first one uses electrode activation times to compute the location of the ectopic site. The second one localizes it by measuring the resetting response of the foci, and the third one, uses wavefront curvature. Specifically for the cylindrical geometry of the blood vessel, we developed a localization procedure that allows to quickly localize the pacemaker.

  10. Topological insulators: Engineered heterostructures

    Science.gov (United States)

    Hesjedal, Thorsten; Chen, Yulin

    2017-01-01

    The combination of topological properties and magnetic order can lead to new quantum states and exotic physical phenomena. In particular, the coupling between topological insulators and antiferromagnets enables magnetic and electronic structural engineering.

  11. Gas insulated substations

    CERN Document Server

    2014-01-01

    This book provides an overview on the particular development steps of gas insulated high-voltage switchgear, and is based on the information given with the editor's tutorial. The theory is kept low only as much as it is needed to understand gas insulated technology, with the main focus of the book being on delivering practical application knowledge. It discusses some introductory and advanced aspects in the meaning of applications. The start of the book presents the theory of Gas Insulated Technology, and outlines reliability, design, safety, grounding and bonding, and factors for choosing GIS. The third chapter presents the technology, covering the following in detail: manufacturing, specification, instrument transformers, Gas Insulated Bus, and the assembly process. Next, the book goes into control and monitoring, which covers local control cabinet, bay controller, control schemes, and digital communication. Testing is explained in the middle of the book before installation and energization. Importantly, ...

  12. Repairing ceramic insulating tiles

    Science.gov (United States)

    Dunn, B. R.; Laymance, E. L.

    1980-01-01

    Fused-silica tiles containing large voids or gauges are repaired without adhesives by plug insertion method. Tiles are useful in conduits for high-temperature gases, in furnaces, and in other applications involving heat insulation.

  13. 建筑外墙集防火、保温、装饰一体组合挂板技术探讨%Exterior Wall Panels Integrated with Functions of Fireproof, Insulation and Decoration

    Institute of Scientific and Technical Information of China (English)

    姜洪; 姜沛彤

    2015-01-01

    By learning the current situation of building energy efficiency in northern China, the panel integrated various functions, including Class A fireproof, exterior insulation and decoration, and the panel system is composed of small load-bearing unit. The construction feasibility of the exterior panel system is analyzed by expounding and verifying materials selection, thermal performance, structure of small unit and its fixtures.%通过了解当前我国北方地区建筑节能情况,设想设计集 A 级防火、外墙保温和外墙面装饰于一体的,小单元独立承重、组合式外墙挂板。通过对其材料的选择、热工性能的验算、小单元结构及其固定件的结构验算,综合分析了该组合式外墙挂板实施的可行性。

  14. Building America Top Innovations 2013 Profile – Exterior Rigid Insulation Best Practices

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2013-09-01

    In this Top Innovation profile, field and lab studies by BSC, PHI, and NorthernSTAR characterize the thermal, air, and vapor resistance properties of rigid foam insulation and describe best practices for their use on walls, roofs, and foundations.

  15. Measure Guideline: Three High Performance Mineral Fiber Insulation Board Retrofit Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Neuhauser, K. [Building Science Corporation, Westford, MA (United States)

    2015-01-01

    This Measure Guideline describes a high performance enclosure retrofit package that uses mineral fiber insulation board, and is intended to serve contractors and designers seeking guidance for non-foam exterior insulation retrofit processes. The guideline describes retrofit assembly and details for wood frame roof and walls and for cast concrete foundations.

  16. Measure Guideline: Three High Performance Mineral Fiber Insulation Board Retrofit Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Neuhauser, Ken [Building Science Corporation, Westford, MA (United States)

    2015-01-01

    This Measure Guideline describes a high performance enclosure retrofit package that uses mineral fiber insulation board. The Measure Guideline describes retrofit assembly and details for wood frame roof and walls and for cast concrete foundations. This Measure Guideline is intended to serve contractors and designers seeking guidance for non-foam exterior insulation retrofit.

  17. Steady thermal stress and strain rates in a rotating circular cylinder under steady state temperature

    Directory of Open Access Journals (Sweden)

    Pankaj Thakur

    2014-01-01

    Full Text Available Thermal stress and strain rates in a thick walled rotating cylinder under steady state temperature has been derived by using Seth’s transition theory. For elastic-plastic stage, it is seen that with the increase of temperature, the cylinder having smaller radii ratios requires lesser angular velocity to become fully plastic as compared to cylinder having higher radii ratios The circumferential stress becomes larger and larger with the increase in temperature. With increase in thickness ratio stresses must be decrease. For the creep stage, it is seen that circumferential stresses for incompressible materials maximum at the internal surface as compared to compressible material, which increase with the increase in temperature and measure n.

  18. Prediction of explosive cylinder tests using equations of state from the PANDA code

    Energy Technology Data Exchange (ETDEWEB)

    Kerley, G.I. [Sandia National Labs., Albuquerque, NM (United States); Christian-Frear, T.L. [RE/SPEC, Inc., Albuquerque, NM (United States)

    1993-09-28

    The PANDA code is used to construct tabular equations of state (EOS) for the detonation products of 24 explosives having CHNO compositions. These EOS, together with a reactive burn model, are used in numerical hydrocode calculations of cylinder tests. The predicted detonation properties and cylinder wall velocities are found to give very good agreement with experimental data. Calculations of flat plate acceleration tests for the HMX-based explosive LX14 are also made and shown to agree well with the measurements. The effects of the reaction zone on both the cylinder and flat plate tests are discussed. For TATB-based explosives, the differences between experiment and theory are consistently larger than for other compositions and may be due to nonideal (finite dimameter) behavior.

  19. Spatially distributed control for optimal drag reduction of the flow past a circular cylinder

    Science.gov (United States)

    Poncet, Philippe; Hildebrand, Roland; Cottet, Georges-Henri; Koumoutsakos, Petros

    We report high drag reduction in direct numerical simulations of controlled flows past circular cylinders at Reynolds numbers of 300 and 1000. The flow is controlled by the azimuthal component of the tangential velocity of the cylinder surface. Starting from a spanwise-uniform velocity profile that leads to high drag reduction, the optimization procedure identifies, for the same energy input, spanwise-varying velocity profiles that lead to higher drag reduction. The three-dimensional variations of the velocity field, corresponding to modes A and B of three-dimensional wake instabilities, are largely responsible for this drag reduction. The spanwise wall velocity variations introduce streamwise vortex braids in the wake that are responsible for reducing the drag induced by the primary spanwise vortices shed by the cylinder. The results demonstrate that extending two-dimensional controllers to three-dimensional flows is not optimal as three-dimensional control strategies can lead efficiently to higher drag reduction.

  20. Centrifugal instability of Stokes layers in crossflow: the case of a forced cylinder wake

    CERN Document Server

    D'Adamo, Juan; Wesfreid, José Eduardo

    2015-01-01

    The wake flow around a circular cylinder at $Re\\approx100$ performing rotatory oscillations has been thoroughly discussed in the literature, mostly focusing on the modifications to the natural B\\'enard-von K\\'arm\\'an vortex street that result from the forced shedding modes locked to the rotatory oscillation frequency. The usual experimental and theoretical frameworks at these Reynolds numbers are quasi-two-dimensional, since the secondary instabilities bringing a three-dimensional structure to the cylinder wake flow occur only at higher Reynolds numbers. In the present paper we show that a three-dimensional structure can appear below the usual three-dimensionalization threshold, when forcing with frequencies lower than the natural vortex shedding frequency, at high amplitudes, as a result of a previously unreported mechanism: a pulsed centrifugal instability of the oscillating Stokes layer at the wall of the cylinder. The present numerical investigation lets us in this way propose a physical explanation for t...

  1. Buckling Analysis for Stiffened Anisotropic Circular Cylinders Based on Sanders Nonlinear Shell Theory

    Science.gov (United States)

    Nemeth, Michael P.

    2014-01-01

    Nonlinear and bifurcation buckling equations for elastic, stiffened, geometrically perfect, right-circular cylindrical, anisotropic shells subjected to combined loads are presented that are based on Sanders' shell theory. Based on these equations, a three-parameter approximate Rayleigh-Ritz solution and a classical solution to the buckling problem are presented for cylinders with simply supported edges. Extensive comparisons of results obtained from these solutions with published results are also presented for a wide range of cylinder constructions. These comparisons include laminated-composite cylinders with a wide variety of shell-wall orthotropies and anisotropies. Numerous results are also given that show the discrepancies between the results obtained by using Donnell's equations and variants of Sanders' equations. For some cases, nondimensional parameters are identified and "master" curves are presented that facilitate the concise representation of results.

  2. Optical nonlinearity enhancement of a periodic array of semiconductor elliptical cylinders

    Science.gov (United States)

    Yang, Baifeng; Zhang, Chengxiang; Tian, Decheng

    2002-11-01

    We investigate the effect of geometric anisotropy on optical nonlinearity enhancement for composites with semiconductor elliptical cylinders in an insulating host in a square lattice. The frequency dependences of the effective nonlinear susceptibility are calculated, and the optical nonlinearity of the composites near the percolation threshold are studied. The calculations are based on the Stroud-Hui relation and a series expression of the space-dependent electric field in periodic composites. The results show that, analogous to metal-insulator composites, a local minimum appears in the nonlinear optical responses near the percolation threshold for two-dimensional percolating semiconductor-insulator composites with geometric anisotropy when the ratio of the bound-electron number density to the effective mass of the electron is large. The results also show that the nonlinearity enhancement increases almost to its maximum when a structure with layers of fluctuating thicknesses forms, and there are no further obvious increases of the enhancement when the thickness fluctuation of the layers decreases. We compare the results of our calculation with those calculated by use of the Boyd-Sipe relation in layered composites, and we conclude that the nonlinearity enhancement reaches its maximum when composites with elliptic cylinders are transformed into Boyd-Sipe-type layered composites.

  3. VORTEX INDUCED VIBRATIONS OF FINNED CYLINDERS

    Institute of Scientific and Technical Information of China (English)

    SHA Yong; WANG Yong-xue

    2008-01-01

    This article presents the results of a numerical simulation on the vortex induced vibration of various finned cylinders at low Reynolds number. The non-dimensional, incompressible Navier-Stokes equations and continuity equation were adopted to simulate the fluid around the cylinder. The cylinder (with or without fins) in fluid flow was approximated as a mass-spring system. The fluid-body interaction of the cylinder with fins and uniform flow was numerically simulated by applying the displacement and stress iterative computation on the fluid-body interfaces. Both vortex structures and response amplitudes of cylinders with various arrangements of fins were analyzed and discussed. The remarkable decrease of response amplitude for the additions of Triangle60 fins and Quadrangle45 fins was found to be comparable with that of bare cylinder. However, the additions of Triangle00 fins and Quadrangle00 fins enhance the response amplitude greatly. Despite the assumption of two-dimensional laminar flow, the present study can give a good insight into the phenomena of cylinders with various arrangements of fins.

  4. 锰渣陶土外墙保温轻质瓷砖的制备及力学性能分析%Analysis on Mechanical Properties and Preparation of Manganese Slag Clay Composite Exterior Wall Thermal Insulation of Lightweight Tiles

    Institute of Scientific and Technical Information of China (English)

    梁峙; 庄旭; 肖扬; 马捷; 顾烨; 倪振威

    2015-01-01

    Taking manganese slag ,clay ,silicon carbide and refractory fiber as the main raw material , the lightweight tiles for exterior wall thermal insulation wall insulation with manganese slag clay were pre‐pared through mixing ,molding ,drying and firing processes .The flexural strength and bibulous rate of the sample were analyzed by measuring different manganese slag content and sintering temperature .The exper‐imental data showed that :under the environment of nitrogen sintering ,the flexural strength and bibulous rate got to the best effects with 20% manganese slag content and the 850 ℃ sintering temperature . Through XRD analysis ,the samples still contained large amounts of manganese elements which showed that they retained the original forms of manganese with a series of excellent performance such as high tem‐perature resistance ,strong flexural strength and corrosion resistance .%以锰渣、陶土、碳化硅、耐火纤维为主要原料,经混合、成型、干燥和烧成等工艺制得锰渣陶土外墙保温轻质瓷砖。实验通过测定不同的锰渣含量和烧结温度,对样品的抗折强度、吸水率进行分析。实验结果表明:当锰矿渣粉质量分数20%、氮气环境下烧结、烧结温度850℃时,产品吸水率、抗折强度达到最佳效果。通过XRD分析得知产品含有大量的锰元素,表明试验在高温下保留了锰的原有形态。试验样品具有耐高温、高强度、抗腐蚀性等一系列优良性能。

  5. RANS simulations of the U and V grooves effect in the subcritical flow over four rotated circular cylinders

    Institute of Scientific and Technical Information of China (English)

    ALONZO-GARCA A; GUTIRREZ-TORRES C del C; JIMNEZ BERNAL J A; MOLLINEDO-PONCE de LEN H R; MARTINEZ-DELGADILLO S A; BARBOSA-SALDAA J G

    2015-01-01

    This paper presents a CFD study about the effect of the V and U grooves in the flow over four cylinders in diamond shape configuration at subcritical flow conditions(Re=41000). Thek-ε Realizable turbulence model was implemented to fully structured hexahedral grids with near-wall refinements. Results showed that the numerical model was able to reproduce the impinging flow pattern and the repulsive forces present in the lateral cylinders of the smooth cylinder array. As a consequence of the flow alignment induced by the grooves, a jet-flow is formed between the lateral cylinders, which could cause an important vortex induced vibration effect especially in the rear cylinder. The magnitudes of the shear stresses at the valleys and peaks for the V grooved cylinders were lower than those of the U grooved cylinders, but the separation points were delayed due the U grooves presence. It is discussed the presence of a blowing effect caused by counter-rotating eddies located near the grooves peaks that cause a decrease of the shear stresses in the valleys, and promote them at the peaks.

  6. Expansion of Metallic Cylinders under Explosive Loading

    Directory of Open Access Journals (Sweden)

    M.S. Bola

    1992-07-01

    Full Text Available The behaviour of expanding metallic cylinders under explosive loading was studied. Using ultra high speed photography, the expansion characteristics of aluminium and copper metallic cylinders have been evaluated with different c/m ratio, and by changing the nature of high explosive. The results obtained are comparable to those predicted by the Gurney's energy and momentum balance equations. A cylinder test has been established for comparative to the metal by octol, TNT, PEK-1, baratol and composition B are calculated. The results are in close agreement with those calculated by Kury et al.

  7. Laminar forced convection slip-flow in a micro-annulus between two concentric cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Avci, Mete; Aydin, Orhan [Karadeniz Technical University, Department of Mechanical Engineering, 61080 Trabzon (Turkey)

    2008-07-01

    Forced convection heat transfer in hydrodynamically and thermally fully developed flows of viscous dissipating gases in annular microducts between two concentric micro cylinders is analyzed analytically. The viscous dissipation effect, the velocity slip and the temperature jump at the wall are taken into consideration. Two different cases of the thermal boundary conditions are considered: uniform heat flux at the outer wall and adiabatic inner wall (Case A) and uniform heat flux at the inner wall and adiabatic outer wall (Case B). Solutions for the velocity and temperature distributions and the Nusselt number are obtained for different values of the aspect ratio, the Knudsen number and the Brinkman number. The analytical results obtained are compared with those available in the literature and an excellent agreement is observed. (author)

  8. Analysis, Predictive Modeling and Hoisted Object Impact Control in Hydro-cylinder Stage- Switching

    Directory of Open Access Journals (Sweden)

    S. V. Kobyzev

    2016-01-01

    Full Text Available The paper considers a problem of dynamic impact of hoisting mechanisms, which are based on the multistage hydro-cylinders, on the hoisted object. Hydro-cylinders have high specific characteristics, but there are also some drawbacks. One of them is an impact at the beginning and at the end of hoist and in switching the stages. And in case of switching the stages under certain conditions the impact in nature can be a high impact impulse. The paper explores the impacts at the beginning of hoist and when switching the stages.Numerical modeling is assumed to be a method of study. To build a mathematical model the following factors have been considered: geometrical cylinder parameters, hydraulic liquid compressibility, and friction between cylinder elements. Elasticity of ground, elasticity of rod, and elasticity of cylinder walls have been ignored.The modeling results allowed us to reveal a hydraulic nature of the stage-switching impact, introduce a formula to estimate the impact impulse value, show the friction effect on the impact impulse value and give a proposal to use a counter-pressure chamber to eliminate the stage-switching impact. An expression for the optimal counter-pressure is presented.The results obtained can find application in designing the new and upgrading the existing hoisting multistage hydro-cylinder mechanisms to increase a hoisting speed and simultaneously eliminate the impact on hoisted object.Compared to existing papers in the field concerned, this one concentrates on revealing a specific hydraulic nature of the stage-switching impact, without regard to dynamics and elasticity of the hoisting mechanism parts other than the cylinder itself.The achieved results find confirmation when compared to the numerical and field data published by other authors.

  9. Analysis of an indirect neutron signature for enhanced UF6 cylinder verification

    Science.gov (United States)

    Kulisek, J. A.; McDonald, B. S.; Smith, L. E.; Zalavadia, M. A.; Webster, J. B.

    2017-02-01

    The International Atomic Energy Agency (IAEA) currently uses handheld gamma-ray spectrometers combined with ultrasonic wall-thickness gauges to verify the declared enrichment of uranium hexafluoride (UF6) cylinders. The current method provides relatively low accuracy for the assay of 235U enrichment, especially for natural and depleted UF6. Furthermore, the current method provides no capability to assay the absolute mass of 235U in the cylinder due to the localized instrument geometry and limited penetration of the 186-keV gamma-ray signature from 235U. Also, the current verification process is a time-consuming component of on-site inspections at uranium enrichment plants. Toward the goal of a more-capable cylinder assay method, the Pacific Northwest National Laboratory has developed the hybrid enrichment verification array (HEVA). HEVA measures both the traditional 186-keV direct signature and a non-traditional, high-energy neutron-induced signature (HEVANT). HEVANT enables full-volume assay of UF6 cylinders by exploiting the relatively larger mean free paths of the neutrons emitted from the UF6. In this work, Monte Carlo modeling is used as the basis for characterizing HEVANT in terms of the individual contributions to HEVANT from nuclides and hardware components. Monte Carlo modeling is also used to quantify the intrinsic efficiency of HEVA for neutron detection in a cylinder-assay geometry. Modeling predictions are validated against neutron-induced gamma-ray spectra from laboratory measurements and a relatively large population of Type 30B cylinders spanning a range of enrichments. Implications of the analysis and findings on the viability of HEVA for cylinder verification are discussed, such as the resistance of the HEVANT signature to manipulation by the nearby placement of neutron-conversion materials.

  10. Analysis of an Indirect Neutron Signature for Enhanced UF6 Cylinder Verification

    Energy Technology Data Exchange (ETDEWEB)

    Kulisek, Jonathan A.; McDonald, Benjamin S.; Smith, Leon E.; Zalavadia, Mital A.; Webster, Jennifer B.

    2017-02-21

    The International Atomic Energy Agency (IAEA) currently uses handheld gamma-ray spectrometers combined with ultrasonic wall-thickness gauges to verify the declared enrichment of uranium hexafluoride (UF6) cylinders. The current method provides relatively low accuracy for the assay of 235U enrichment, especially for natural and depleted UF6. Furthermore, the current method provides no capability to assay the absolute mass of 235U in the cylinder due to the localized instrument geometry and limited penetration of the 186-keV gamma-ray signature from 235U. Also, the current verification process is a time-consuming component of on-site inspections at uranium enrichment plants. Toward the goal of a more-capable cylinder assay method, the Pacific Northwest National Laboratory has developed the hybrid enrichment verification array (HEVA). HEVA measures both the traditional 186-keV direct signature and a non-traditional, high-energy neutron-induced signature (HEVANT). HEVANT enables full-volume assay of UF6 cylinders by exploiting the relatively larger mean free paths of the neutrons emitted from the UF6. In this work, Monte Carlo modeling is used as the basis for characterizing HEVANT in terms of the individual contributions to HEVANT from nuclides and hardware components. Monte Carlo modeling is also used to quantify the intrinsic efficiency of HEVA for neutron detection in a cylinder-assay geometry. Modeling predictions are validated against neutron-induced gamma-ray spectra from laboratory measurements and a relatively large population of Type 30B cylinders spanning a range of enrichments. Implications of the analysis and findings on the viability of HEVA for cylinder verification are discussed, such as the resistance of the HEVANT signature to manipulation by the nearby placement of neutron-conversion materials.

  11. Thermally Insulating, Kinematic Tensioned-Fiber Suspension

    Science.gov (United States)

    Voellmer, George M.

    2004-01-01

    A salt pill and some parts of a thermally insulating, kinematic suspension system that holds the salt pill rigidly in an adiabatic-demagnetization refrigerator (ADR) is presented. "Salt pill" in this context denotes a unit comprising a cylindrical container, a matrix of gold wires in the container, and a cylinder of ferric ammonium alum (a paramagnetic salt) that has been deposited on the wires. The structural members used in this system for both thermal insulation and positioning are aromatic polyamide fibers (Kevlar(R) or equivalent) under tension. This suspension system is designed to satisfy several special requirements to ensure the proper operation of the ADR. These requirements are to (1) maintain the salt pill at a specified position within the cylindrical bore of an electromagnet; (2) prevent vibrations, which would cause dissipation of heat in the salt pill; and (3) minimize the conduction of heat from the electromagnet bore and other neighboring objects to the salt pill; all while (4) protecting the salt pill (which is fragile) against all tensile and bending loads other than those attributable to its own weight. In addition, the system is required to consist of two subsystems -- one for the top end and one for the bottom end of the salt pill -- that can be assembled and tensioned separately from each other and from the salt pill, then later attached to the salt pill.

  12. Effect of façade impregnation on feasibility of capillary active thermal internal insulation for a historic dormitory – A hygrothermal simulation study

    DEFF Research Database (Denmark)

    Finken, Gholam Reza; Bjarløv, Søren Peter; Peuhkuri, Ruut Hannele

    2016-01-01

    Internal insulation of external walls is known to create moisture performance challenges due to increased moisture levels and condensation risk on the cold side of the insulation. Capillary active/hydrophilic insulations have been introduced to solve these moisture problems, since they are able t...

  13. Identification of building applications for a variable-conductance insulation

    Energy Technology Data Exchange (ETDEWEB)

    Potter, T F [National Renewable Energy Lab., Golden, CO (United States); Tuluca, A [Winter (Steven) Associates, Inc., New York, NY (United States)

    1992-07-01

    Recent experiments have confirmed the feasibility of controllable, reversible disabling of a vacuum insulation panel, which may result in the development of energy-efficient building envelope components. These components could extend the managed energy exchange through the building envelope from about 30% (typical with fenestration systems in commercial buildings), to as much as 90% of the gross wall and roof areas. Further investigation will be required to optimized the thermal response and the magnitude of the R-value swing (from a difference between insulating and conducting insulating values of 4 to as high as a factor of 100). The potential for energy reduction by using the variable-conductance insulation in the building envelope is discussed, and other potential building applications are mentioned.

  14. 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...

  15. Oscillations and translation of a free cylinder in a confined flow

    CERN Document Server

    D'Angelo, Maria Veronica; Auradou, Harold

    2013-01-01

    An oscillatory instability has been observed experimentally on an horizontal cylinder free to move and rotate between two parallel vertical walls of distance H; its characteristics differ both from vortex shedding driven oscillations and from those of tethered cylinders in the same geometry. The vertical motion of the cylinder, its rotation about its axis and its transverse motion across the gap have been investigated as a function of its diameter D, its density s, of the mean vertical velocity U of the fluid and of its viscosity. For a blockage ratio D/H above 0.5 and a Reynolds number Re larger then 14, oscillations of the rolling angle of the cylinder about its axis and of its transverse coordinate in the gap are observed together with periodic variations of the vertical velocity. Their frequency f is the same for the sedimentation of the cylinder in a static fluid (U = 0) and for a non-zero mean flow (U 6= 0). The Strouhal number St associated to the oscillation varies as 1/Re with : St.Re = 3 $\\pm$ 0.15....

  16. 砂岩质煤矸石制备外墙泡沫保温材料%Preparation of Thermal Insulation Foam Material for Exterior Wall with Sandstone Coal Gangue

    Institute of Scientific and Technical Information of China (English)

    孙晓刚; 李小庆; 邱景平; 邢军; 赵英良

    2015-01-01

    In order to seek the sources of raw materials for exterior foam insulation material,through optimizing of particle gradation,improving plasticity and adding inorganic plasticizer,techniques for increasing its plasticity and making the qualified product are found out,with the sandstone coal gangue and polishing tile waste as the main raw materials. Analysis is made on the effect of bulk density,compressive strength and thermal conductivity,with different amount of polishing tile waste and addi-tive,to design the orthogonal experiment to determine the suitable additive content. The optimum sintering procedure is con-firmed with orthogonal test of choosing preheating temperature,preheating time,sintering temperature and holding time as four main factors,which has great effect on the sintering procedure. The results provide a new way to produce new building materials for the comprehensive utilization of industrial waste.%为寻求外墙泡沫保温材料的原料来源,以砂岩质煤矸石和抛光砖泥为主要原料,通过优化颗粒级配、陈化增塑、添加无机增塑剂等措施,探索提高原料可塑性、生产合格制品的工艺技术。通过抛光砖泥和添加剂掺量的不同,分析掺入料对制品体积密度、抗压强度、导热系数的影响,设计正交试验确定适宜的添加剂含量;以对烧结制度影响较大的预热温度、预热时间、烧结温度和保温时间为4个因素设计正交试验,确定烧制保温材料的最佳烧结制度。该研究结果为综合利用工业废料制备新型建材提供了新的途径。

  17. Development, testing and application of extruded polystyrene foam (XPS) insulation with improved thermal properties; Polystyrol-Extruderschaum mit verbesserten waermetechnischen Eigenschaften - Entwicklung, Pruefung und Anwendung

    Energy Technology Data Exchange (ETDEWEB)

    Bunge, Friedhelm [Forschung und Entwicklung Dow Building Solutions, Horgen (Switzerland); Merkel, Holger [Anwendungstechnik Dow Building Solutions, Schwalbach (Germany)

    2011-02-15

    Improved extruded polystyrene foam (XPS) insulation with lower thermal conductivity has been developed. This enables meeting the increased requirements for sustainable building insulation with better material efficiency. The proven mechanical and hygro-thermal properties of XPS insulation are maintained. This first product generation has been developed primarily for external perimeter insulation of basement walls and floors as well as for the insulation of cavity walls. The CO{sub 2} foaming technology meets the sustainability requirements for building products. (Copyright copyright 2011 Ernst and Sohn Verlag fuer Architektur und technische Wissenschaften GmbH and Co. KG, Berlin)

  18. Magnetohydrodynamic Flow Between Concentric Rotating Porous Cylinders

    Directory of Open Access Journals (Sweden)

    S. N. Dube

    1971-10-01

    Full Text Available An attempt has been made to study the steady laminar flow of a incompressible electrically conducting fluid between infinitely long concentric rotating porous cylinders under the influence of radial magnetic field. A solution has been obtained under the assumption of uniform conditions along the axis of the cylinders. The cylinders being porous, a hyperbolic radial velocity distribution has been superimposed over the circumferential velocity produced due to rotation. There is a Bernoulli type pressure variation in the radial in the direction. When the inner cylinder is at rest the shearing stress at it and the torque transmitted to it decrease as R (=v/Sub/1y/Sub1/v= v/Sub2y/Sub2/v increases and the magnetic parameter lambda (=4sigma mue/sube/sup2A/Sup2/Mue will further decrease them.

  19. Suppression of Brazier Effect in Multilayered Cylinders

    Directory of Open Access Journals (Sweden)

    Hiroyuki Shima

    2014-01-01

    Full Text Available When a straight hollow tube having circular cross-section is bent uniformly into an arc, the cross-section tends to ovalize or flatten due to the in-plane stresses induced by bending; this ovalization phenomenon is called the Brazier effect. The present paper is aimed at theoretical formulation of the Brazier effect observed in multilayered cylinders, in which a set of thin hollow cylinders are stacked concentrically about the common axis. The results indicate that mechanical couplings between stacked cylinders are found to yield pronounced suppression of the cross-sectional ovalization. Numerical computations have been performed to measure the degree of suppression in a quantitative manner and to explore how it is affected by the variations in the bending curvature, the number of stacked cylinders, and the interlayer coupling strength.

  20. Coupled dynamics of vortex-induced vibration and stationary wall at low Reynolds number

    Science.gov (United States)

    Li, Zhong; Jaiman, Rajeev K.; Khoo, Boo Cheong

    2017-09-01

    The flow past an elastically mounted circular cylinder placed in proximity to a plane wall is numerically studied in both two dimensions (2D) and three dimensions (3D). This paper aims to explain the mechanism of the cylinder bottom shear layer roll-up suppression in the context of laminar vortex-induced vibration (VIV) of a cylinder placed in the vicinity of a plane stationary wall. In 2D simulations, VIV of a near-wall cylinder with structure-to-displaced fluid mass ratios of m* = 2 and 10 is investigated at the Reynolds number of Re = 100 at a representative gap ratio of e/D = 0.90, where e denotes the gap distance between the cylinder surface and the plane wall. First, the cylinder is placed at five different upstream distances, LU, to study the effects of the normalized wall boundary layer thickness, δ /D , on the hydrodynamic quantities involved in the VIV of a near-wall cylinder. It is found that the lock-in range shifts towards the direction of the higher reduced velocity Ur as δ /D increases and that the lock-in range widens as m* reduces. Second, via visualization of the vortex shedding patterns, four different modes are classified and the regime maps are provided for both m* = 2 and 10. Third, the proper orthogonal decomposition analysis is employed to assess the cylinder bottom shear layer roll-up suppression mechanism. For 3D simulations at Re = 200, the circular cylinder of a mass ratio of m* = 10 with a spanwise length of 4D is placed at a gap ratio of e/D = 0.90 and an upstream distance of LU = 10D. The 3D vortex patterns are investigated to re-affirm the vortex shedding suppression mechanism. The pressure distributions around the cylinder are identified within one oscillation cycle of VIV. The pressure and the shear stress distributions on the bottom wall are examined to demonstrate the effects of near-wall VIV on the force distributions along the plane wall. It is found that both the suction pressure and the shear stress right below the cylinder

  1. Thermal-hydraulic characterization of the natural circulation of air between two vertical cylinders enclosed in a rectangular cavity

    Science.gov (United States)

    Alfredo Payan-Rodriguez, Luis; Rivera-Solorio, Carlos Ivan; Villarreal-Garcia, Salvador; Garcia-Cuellar, Alejadro Javier; Ramirez-Tijerina, Ramon

    2008-11-01

    This work presents the results of an experimental analysis focused on the characterization of the natural circulation of air in the vicinity of two vertical cylinders. A three dimensional cavity encloses each cylinder, where one of them is a heat source and the other is a heat sink. A wall with two holes of variable diameter delimits and connects the two enclosures in order to restrict the air flow exchanged between them. The distance between the center lines of the cylinders was varied with the purpose of measuring the effect of the surrounding walls on the natural circulation. All configurations were tested for different heat generation rates. A Particle Image Velocimeter was used to obtain the flow patterns and a set of thermocouples was installed to measure the temperature field. The experimental results are analyzed and discussed.

  2. Discrete model in the analysis of residual stresses in unidirectional winding cylinders made of fiber-reinforced plastic

    Directory of Open Access Journals (Sweden)

    Turusov Robert Alekseevich

    2015-01-01

    Full Text Available Today works in cosmos and at great sea depths are becoming very current. In order to execute these works tanks with great mass perfection are needed, which represents the relation of the product of pressure and inner volume to its mass. Usually such tanks are usually produced as a cocoon by winding methods, which can be automated. The simplest model of a cocoon is a cylinder with hemispheric blinds at the edges. The radial stresses arise in thick walled composite cylinders due to anisotropic thermal shrinkage during cooling process after curing. It also can lead to formation of radial cracks. The results of the analyses when a material is simplified to a homogenous orthotropic material show a very small residual radial stress value. In this paper we have used discrete model to evaluate residual radial stresses in thick-walled unidirectional filament wound cylinder and the results were compared to the results of homogenous orthotropic model.

  3. Hybrid Enrichment Assay Methods for a UF6 Cylinder Verification Station: FY10 Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Leon E.; Jordan, David V.; Orton, Christopher R.; Misner, Alex C.; Mace, Emily K.

    2010-08-01

    HPGe verification station at AREVA, and the IAEA’s uncertainty target values for feed, tail and product cylinders. A summary of the major findings from the field measurements and subsequent analysis follows: • Traditional enrichment-meter assay using specially collimated NaI spectrometers and a Square-Wave-Convolute algorithm can achieve uncertainties comparable to HPGe and LaBr for product, natural and depleted cylinders. • Non-traditional signatures measured using NaI spectrometers enable interrogation of the entire cylinder volume and accurate measurement of absolute 235U mass in product, natural and depleted cylinders. • A hybrid enrichment assay method can achieve lower uncertainties than either the traditional or non-traditional methods acting independently because there is a low degree of correlation in the systematic errors of the two individual methods (wall thickness variation and 234U/235U variation, respectively). This work has indicated that the hybrid NDA method has the potential to serve as the foundation for an unattended cylinder verification station. When compared to today’s handheld cylinder-verification approach, such a station would have the following advantages: 1) improved enrichment assay accuracy for product, tail and feed cylinders; 2) full-volume assay of absolute 235U mass; 3) assay of minor isotopes (234U and 232U) important to verification of feedstock origin; single instrumentation design for both Type 30B and Type 48 cylinders; and 4) substantial reduction in the inspector manpower associated with cylinder verification.

  4. Dynamics of immiscible liquids in a rotating horizontal cylinder

    Science.gov (United States)

    Kozlov, N. V.; Kozlova, A. N.; Shuvalova, D. A.

    2016-11-01

    The dynamics of an interface between two immiscible liquids of different density is studied experimentally in a horizontal cylinder at rotation in the gravity field. Two liquids entirely fill the cavity volume, and the container is rotated sufficiently fast so that the liquids are centrifuged. The light liquid forms a column extended along the rotation axis, and the heavy liquid forms an annular layer. Under the action of gravity, the light liquid column displaces steadily along the radius, downwards in the laboratory frame. As a result, fluid oscillations in the cavity frame are excited at the interface, which lead to the generation of a steady streaming, and the fluid comes into a slow lagging rotation with respect to the cylinder walls. The dynamics of the studied system is determined by the ratio of the gravity acceleration to the centrifugal one—the dimensionless acceleration. In experiments, the system is controlled by the means of variation of the rotation rate, i.e., of the centrifugal force. At a critical value of the dimensionless acceleration the circular interface looses stability, and an azimuthal wave is excited. This leads to a strong increase in the interface differential velocity. A theoretical analysis is done based on the theory of centrifugal waves and a frequency equation is obtained. Experimental results are in good agreement with the theory at the condition of small wave amplitudes. Mechanism of steady streaming generation is analyzed based on previously published theoretical results obtained for the limiting case when the light phase is a solid cylinder. A qualitative agreement is found.

  5. Spray Foam Exterior Insulation with Stand-Off Furring

    Energy Technology Data Exchange (ETDEWEB)

    Herk, Anatasia [IBACOS, Inc., Pittsburgh, PA (United States); Baker, Richard [IBACOS, Inc., Pittsburgh, PA (United States); Prahl, Duncan [IBACOS, Inc., Pittsburgh, PA (United States)

    2014-03-01

    IBACOS, in collaboration with GreenHomes America, was contracted by the New York State Energy Research and Development Authority to research exterior wall insulation solutions. This research investigated cost-effective deep energy retrofit (DER) solutions for improving the building shell exterior while achieving a cost-reduction goal, including reduced labor costs to reach a 50/50 split between material and labor. The strategies included exterior wall insulation plus energy upgrades as needed in the attic, mechanical and ventilation systems, and basement band joist, walls, and floors. The work can be integrated with other home improvements such as siding or window replacement. This strategy minimizes physical connections to existing wall studs, encapsulates existing siding materials (including lead paint) with spray foam, and creates a vented rain screen assembly to promote drying. GreenHomes America applied construction details created by IBACOS to a test home. 2x4 framing members were attached to the wall at band joists and top plates using "L" clips, with spray foam insulating the wall after framing was installed. Windows were installed simultaneously with the framing, including extension jambs. The use of clips in specific areas provided the best strength potential, and "picture framing" the spray foam held the 2x4s in place. Short-term testing was performed at this house, with monitoring equipment installed for long-term testing. Testing measurements will be provided in a later report, as well as utility impact (before and after), costs (labor and materials), construction time, standard specifications, and analysis for the exterior wall insulation strategy.

  6. Spray Foam Exterior Insulation with Stand-Off Furring

    Energy Technology Data Exchange (ETDEWEB)

    Herk, A.; Baker, R.; Prahl, D.

    2014-03-01

    IBACOS, in collaboration with GreenHomes America, was contracted by the New York State Energy Research and Development Authority to research exterior wall insulation solutions. This research investigated cost-effective deep energy retrofit (DER) solutions for improving the building shell exterior while achieving a cost-reduction goal, including reduced labor costs to reach a 50/50 split between material and labor. The strategies included exterior wall insulation plus energy upgrades as needed in the attic, mechanical and ventilation systems, and basement band joist, walls, and floors. The work can be integrated with other home improvements such as siding or window replacement. This strategy minimizes physical connections to existing wall studs, encapsulates existing siding materials (including lead paint) with spray foam, and creates a vented rain screen assembly to promote drying. GreenHomes America applied construction details created by IBACOS to a test home. 2x4 framing members were attached to the wall at band joists and top plates using 'L' clips, with spray foam insulating the wall after framing was installed. Windows were installed simultaneously with the framing, including extension jambs. The use of clips in specific areas provided the best strength potential, and 'picture framing' the spray foam held the 2x4s in place. Short-term testing was performed at this house, with monitoring equipment installed for long-term testing. Testing measurements will be provided in a later report, as well as utility impact (before and after), costs (labor and materials), construction time, standard specifications, and analysis for the exterior wall insulation strategy.

  7. Sub-wavelength resonances in polygonal metamaterial cylinders

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Breinbjerg, Olav

    2008-01-01

    It has been shown that the sub-wavelength resonances of circular MTM cylinders also occur for polygonal MTM cylinders. This is the case for lossless and non-dispersive cylinders as well as lossy and dispersive cylinders. The sub-wavelength resonances are thus not limited to structures of canonical...

  8. Dynamic Fracture Simulations of Explosively Loaded Cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, Carly W. [Univ. of California, Davis, CA (United States). Dept. of Civil and Environmental Engineering; Goto, D. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-11-30

    This report documents the modeling results of high explosive experiments investigating dynamic fracture of steel (AerMet® 100 alloy) cylinders. The experiments were conducted at Lawrence Livermore National Laboratory (LLNL) during 2007 to 2008 [10]. A principal objective of this study was to gain an understanding of dynamic material failure through the analysis of hydrodynamic computer code simulations. Two-dimensional and three-dimensional computational cylinder models were analyzed using the ALE3D multi-physics computer code.

  9. Study of Multi-Cylinder Engine Manifolds

    Science.gov (United States)

    1944-10-31

    were developed so that mnifolds for any number of cylinders could be analyzed for max- I= zm volumetrie efficiency. Eletricaleebanioal analoCies can be...deceleration of the air& The vibrations are almot Identical to thse In single cylinder intake pipes. The mmi- a= volumetrie efficiency bould be...pipe 14 in. total volume 7- In- 3 area of pipew 0.86 in 2 Table I gives the actual and calculated speeds for peak volumetri efficiencies for a sIngle

  10. Application of foam concrete in wall and roof insulation engineering%泡沫混凝土现浇墙体与屋面保温层工程应用以及其保温性能的讨论

    Institute of Scientific and Technical Information of China (English)

    袁伟; 丁来彬; 周成

    2014-01-01

    通过分析研究泡沫混凝土应用于墙体与屋面保温层实际工程,并对其建筑物的保温性能及材料的物理力学性能进行了检测和讨论。结合工程实例,总结出泡沫混凝土整浇工艺存在的优势与不足。泡沫混凝土强度和导热系数检测结果均达到产品标准相关技术指标要求,建筑物围护结构热工检测结果达到严寒和寒冷地区居住建筑节能设计标准要求。%By analyzing the application of foam concrete in wall and roof insulation engineering, and thermal performance of buildings and the physical and mechanical properties of materials are discussed.

  11. Moisture Management for High R-Value Walls

    Energy Technology Data Exchange (ETDEWEB)

    Lepage, R.; Schumacher, C.; Lukachko, A.

    2013-11-01

    The following report explains the moisture-related concerns for High R-value wall assemblies and discusses past Building America research work that informs this study. Hygrothermal simulations were prepared for several common approaches to High R-value wall construction in six cities (Houston, Atlanta, Seattle, St. Louis, Chicago, and International Falls) representing a range of climate zones (2, 3, 4C, 4, 5A, and 7, respectively). The simulations are informed by experience gained from past research in this area and validated by field measurement and forensic experience. The modeling program was developed to assess the moisture durability of the wall assemblies based on three primary sources of moisture: construction moisture, air leakage condensation, and bulk water leakage. The peak annual moisture content of the wood based exterior sheathing was used to comparatively analyze the response to the moisture loads for each of the walls in each given city. Walls which experienced sheathing moisture contents between 20% and 28% were identified as risky, whereas those exceeding 28% were identified as very high risk. All of the wall assemblies perform well under idealized conditions. However, only the walls with exterior insulation, or cavity insulation which provides a hygrothermal function similar to exterior insulation, perform adequately when exposed to moisture loads. Walls with only cavity insulation are particularly susceptible to air leakage condensation. None of the walls performed well when a precipitation based bulk water leak was introduced to the backside of the sheathing, emphasizing the importance of proper flashing details.

  12. Thermal performance of concrete masonry unit wall systems

    Energy Technology Data Exchange (ETDEWEB)

    Kosny, J.

    1995-12-31

    New materials, modern building wall technologies now available in the building marketplace, and unique, more accurate, methods of thermal analysis of wall systems create an opportunity to design and erect buildings where thermal envelopes that use masonry wall systems can be more efficient. Thermal performance of the six masonry wall systems is analyzed. Most existing masonry systems are modifications of technologies presented in this paper. Finite difference two-dimensional and three-dimensional computer modeling and unique methods of the clear wall and overall thermal analysis were used. In the design of thermally efficient masonry wall systems is t to know how effectively the insulation material is used and how the insulation shape and its location affect the wall thermal performance. Due to the incorrect shape of the insulation or structural components, hidden thermal shorts cause additional heat losses. In this study, the thermal analysis of the clear wall was enriched with the examination of the thermal properties of the wall details and the study of a quantity defined herein the Thermal Efficiency of the insulation material.

  13. Statistical analyses of a screen cylinder wake

    Science.gov (United States)

    Mohd Azmi, Azlin; Zhou, Tongming; Zhou, Yu; Cheng, Liang

    2017-02-01

    The evolution of a screen cylinder wake was studied by analysing its statistical properties over a streamwise range of x/d={10-60}. The screen cylinder was made of a stainless steel screen mesh of 67% porosity. The experiments were conducted in a wind tunnel at a Reynolds number of 7000 using an X-probe. The results were compared with those obtained in the wake generated by a solid cylinder. It was observed that the evolution of the statistics in the wake of the screen cylinder was different from that of a solid cylinder, reflecting the differences in the formation of the organized large-scale vortices in both wakes. The streamwise evolution of the Reynolds stresses, energy spectra and cross-correlation coefficients indicated that there exists a critical location that differentiates the screen cylinder wake into two regions over the measured streamwise range. The formation of the fully formed large-scale vortices was delayed until this critical location. Comparison with existing results for screen strips showed that although the near-wake characteristics and the vortex formation mechanism were similar between the two wake generators, variation in the Strouhal frequencies was observed and the self-preservation states were non-universal, reconfirming the dependence of a wake on its initial condition.

  14. Insulation materials. Cellulose fiber and expanded polystyrene insulations

    OpenAIRE

    Viladot Bel, Cèlia

    2017-01-01

    The main role of thermal insulation materials in a building envelope are to prevent heat loss and provide thermal comfort for a building's interior. The factor that characterizes an insulation material's effectiveness is its thermal conductivity λ (measured in W/mK). The lower a material's thermal conductivity, the more effective it is as an insulator. Traditional insulation materials include glass fibre, stone wool, expanded polystyrene, and polyurethane foam. While these materials are effic...

  15. Transcription Independent Insulation at TFIIIC-Dependent Insulators

    OpenAIRE

    Valenzuela, Lourdes; Dhillon, Namrita; Kamakaka, Rohinton T.

    2009-01-01

    Chromatin insulators separate active from repressed chromatin domains. In yeast the RNA pol III transcription machinery bound to tRNA genes function with histone acetylases and chromatin remodelers to restrict the spread of heterochromatin. Our results collectively demonstrate that binding of TFIIIC is necessary for insulation but binding of TFIIIB along with TFIIIC likely improves the probability of complex formation at an insulator. Insulation by this transcription factor occurs in the abse...

  16. Uniform flow around a circular cylinder in the subcritical range - using the Self-induced angular Moment Method turbulence model

    DEFF Research Database (Denmark)

    Johansson, Jens; Nielsen, Mogens Peter

    The uniform flow around a circular cylinder at Reynolds number 1e5 is simulated in a three dimensional domain by means of the newly developed Self-induced angular Moment Method, SMoM, turbulence model. The global force coefficients, Strouhal number, pressure distributions and wall shear stress...

  17. Charged aerodynamics of a Low Earth Orbit cylinder

    Science.gov (United States)

    Capon, C. J.; Brown, M.; Boyce, R. R.

    2016-11-01

    This work investigates the charged aerodynamic interaction of a Low Earth Orbiting (LEO) cylinder with the ionosphere. The ratio of charge to neutral drag force on a 2D LEO cylinder with diffusely reflecting cool walls is derived analytically and compared against self-consistent electrostatic Particle-in-Cell (PIC) simulations. Analytical calculations predict that neglecting charged drag in an O+ dominated LEO plasma with a neutral to ion number density ratio of 102 will cause a 10% over-prediction of O density based on body accelerations when body potential (ɸB) is ≤ -390 V. Above 900 km altitude in LEO, where H+ becomes the dominant ion species, analytical predictions suggest charge drag becomes equivalent to neutral drag for ɸB ≤ -0.75 V. Comparing analytical predictions against PIC simulations in the range of 0 PIC simulations, our in-house 6 degree of freedom orbital propagator saw a reduction in the semi-major axis of a 10 kg satellite at 700 km of 6.9 m/day and 0.98 m/day at 900 km compared that caused purely by neutral drag - 0.67 m/day and 0.056 m/day respectively. Hence, this work provides initial evidence that charged aerodynamics may become significant compared to neutral aerodynamics for high voltage LEO bodies.

  18. Super insulating aerogel glazing

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Jensen, Karsten Ingerslev; Kristiansen, Finn Harken

    2004-01-01

    Monolithic silica aerogel offers the possibility of combining super insulation and high solar energy transmittance, which has been the background for a previous and a current EU project on research and development of monolithic silica aerogel as transparent insulation in windows. Generally, windows...... form the weakest part of the thermal envelope with respect to heat loss coefficient, but on the other hand also play an important role for passive solar energy utilisation. For window orientations other than south, the net energy balance will be close to or below zero. However, the properties...

  19. An Approximate Solution and Master Curves for Buckling of Symmetrically Laminated Composite Cylinders

    Science.gov (United States)

    Nemeth, Michael P.

    2013-01-01

    Nondimensional linear-bifurcation buckling equations for balanced, symmetrically laminated cylinders with negligible shell-wall anisotropies and subjected to uniform axial compression loads are presented. These equations are solved exactly for the practical case of simply supported ends. Nondimensional quantities are used to characterize the buckling behavior that consist of a stiffness-weighted length-to-radius parameter, a stiffness-weighted shell-thinness parameter, a shell-wall nonhomogeneity parameter, two orthotropy parameters, and a nondimensional buckling load. Ranges for the nondimensional parameters are established that encompass a wide range of laminated-wall constructions and numerous generic plots of nondimensional buckling load versus a stiffness-weighted length-to-radius ratio are presented for various combinations of the other parameters. These plots are expected to include many practical cases of interest to designers. Additionally, these plots show how the parameter values affect the distribution and size of the festoons forming each response curve and how they affect the attenuation of each response curve to the corresponding solution for an infinitely long cylinder. To aid in preliminary design studies, approximate formulas for the nondimensional buckling load are derived, and validated against the corresponding exact solution, that give the attenuated buckling response of an infinitely long cylinder in terms of the nondimensional parameters presented herein. A relatively small number of "master curves" are identified that give a nondimensional measure of the buckling load of an infinitely long cylinder as a function of the orthotropy and wall inhomogeneity parameters. These curves reduce greatly the complexity of the design-variable space as compared to representations that use dimensional quantities as design variables. As a result of their inherent simplicity, these master curves are anticipated to be useful in the ongoing development of

  20. Red-yellow CdSSe-ZnS SLs and blue-green SrS and CdSSe-SrS SLs double insulating EL devices prepared by hot wall epitaxy

    Science.gov (United States)

    Fujiyasu, H.; Takeuchi, Y.; Hikida, K.; Masuo, K.; Gotou, Y.; Kiichi, T.; Ishino, K.; Ishida, A.

    1993-03-01

    We have prepared CdSSe (Mn doped, Eg = 1.9-2.5 eV, lattice constant a = 6.1-5.8 Å)-ZnS ( Eg = 3.56 eV, a = 5.41 Aring;) superlattices (SLs) (A) and SrS (Ce doped, Eg = 4.4 eV, a = 6.02 Å) and CdSSe-SrS (Ce doped) SL active layer by hot wall epitaxy and measured the electroluminescence characteristics. For (A) the maximum luminance was 800 cd/m 2 at applied sinusoidal voltage ( V0-p 200 V) of 1 kHz and the peak luminance spectra wave length was 610 nm due to the large strain for the lattice mismatch (8-15%) between the CdSSe and ZnS layers. The maximum illuminance and CIE (Commisson Internationale de Enluminare) chromaticity of the CdS(Mn)-ZnS SL abd CdSe-ZnS SL devices were 557 cd/m 2 and ( x, y) = (0.58, 0.41), and 982 cd/m 2 and (0.61, 0.38), respectively. For (B), the maximum luminance of the SrS active layer device was 700 cd/m 2 at a voltage of 340 V. For CdSSe-SrS SLs blue-color EL emission was observed in the photon wave length region less than 450 nm due to carrier dropping into the quantum wells of the SL active layer device.

  1. Guided wave modes in porous cylinders: experimental results.

    Science.gov (United States)

    Wisse, C J; Smeulders, D M J; van Dongen, M E H; Chao, G

    2002-09-01

    In this paper guided wave modes in porous media are investigated. A water-saturated porous cylinder is mounted in the test section of a shock tube. Between the porous sample and the wall of the shock tube a water-filled annulus exists. For very small annulus width, bulk waves are generated and one-dimensional modeling is sufficient. Otherwise two-dimensional effects become important and multiple guided wave modes occur. Using a newly developed traversable positioning system in the shock tube, the frequency-dependent phase velocities and damping coefficients in the 1-120 kHz frequency range were measured. Prony's method was used for data processing. Agreement was found between the experimental data and the two-dimensional modeling of the shock tube which was based on Biot's theory.

  2. Conceptual Ideas for New Nondestructive UF6 Cylinder Assay Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Karen A. [Los Alamos National Laboratory

    2012-05-02

    have more potential for this application and should be assessed quantitatively. The next set of techniques leverage scintillator detectors that are sensitive to both neutron and gamma radiation. The first is the BC-523A capture-gated organic liquid scintillator. The detector response from several different neutron energies has been characterized and is included in the study. The BC-523A has not yet been tested with UF{sub 6} cylinders, but the application appears to be well suited for this technology. The second detector type is a relatively new inorganic scintillator called CLYC. CLYC provides a complementary detection approach to the HEVA and PNEM systems that could be used to determine uranium enrichment in UF{sub 6} cylinders. In this section, the conceptual idea for an integrated CLYC-HEVA/PNEM system is explored that could yield more precision and robustness against systemic uncertainties than any one of the systems by itself. This is followed by a feasibility study on using alpha-particle-induced reaction gamma-rays as a way to estimate {sup 234}U abundance in UF{sub 6}. Until now, there has been no readily available estimate of the strength of these reaction gamma-rays. Thick target yields of the chief reaction gammas are computed and show that they are too weak for practical safeguards applications. In special circumstances where long count times are permissible, the 1,275 keV F({alpha},x{gamma}) is observable. Its strength could help verify an operator declaration provided other knowledge is available (especially the age). The other F({alpha},x{gamma}) lines are concealed by the dominant uranium line spectrum and associated continuum. Finally, the last section provides several ideas for electromagnetic and acoustic nondestructive evaluation (NDE) techniques. These can be used to measure cylinder wall thickness, which is a source of systematic uncertainty for gamma-ray-based NDA techniques; characterize the UF{sub 6} filling profile inside the cylinder, which

  3. Calculating the Insulated Car Roof Opening System Components and Strength Analysis of Car Design in Its Various Embodiments

    Directory of Open Access Journals (Sweden)

    V. S. Kopytov

    2016-01-01

    Full Text Available Opening roof cars can be used in transportation of a diversity of goods that require weather protection. Their operation allows us to fulfill the tasks of the Ministry of Railways that is to ensure both the qualitative and lossless transportation of various national economy and special loads and the significant improvement in the technical and economic indexes of the industry. Thus, there are three embodiment options of the opening roofs: single-leaf roof with axial of rotation along one car side; double-leaf roof with axial of rotation of its flaps along both car sides; single-leaf roof with axial of rotation along the car end wall. The work analyses and compares the first two options of the opening systems of the car roof. Analysis of various schemes of opening the roof-insulated cars is based on kinematic and force calculations. The paper defines how the changing length of hydraulic cylinders depends on the stroke and on the arm of applied force, depending on the opening roof angle for various embodiment options. To find the forces acting on the cylinders were determined the forces acting on the roof and the total applied moment of all the forces acting on them with respect to the axial of rotation. Thus, the total applied moment was considered to comprise the weighting unbalance moments of the roof and snow on it, as well as a moment of the force of wind acting on the roof (dead wind or downwind. Upon finding how the changing total moment of the force applied to the roof depends on the rotation angle and on the change of the applied force arm of hydraulic cylinders, the work determines the forces acting on the cylinders. The maximum tensile and compression force acting on the cylinders allows us to define their geometric characteristics such as piston stroke, diameter of the rod, piston-and rod-working cavity. Using a software package SADAS (developed at the Department "Rocket Launching Complexes" in BMSTU the core models were built and

  4. Humidity buffering of interior spaces by porous, absorbent insulation

    DEFF Research Database (Denmark)

    Padfield, Tim

    1999-01-01

    Thermal insulation made from wool will have a detectable, but small, moderating influence onvariation in the indoor relative humidity in a house with less than half an air change per hour andwith porous wall surfaces, such as paper, limewash or silicate paint.Water vapour distributes itself fairly...... to practical insignificance.Absorbent insulation will only have a useful influence on the indoor climate if the entire wall isredesigned to give a much more porous structure. This development would conflict with thecustom of putting a vapour barrier or vapour retarder close to the inside surface of a wall....... A morepractical way of moderating the indoor relative humidity would be to use an absorbent interiorfinish instead of the customary gypsum board. The excellent performance of end grain wood as aninterior finish is shown for comparison.The experiments reported here show the influence on the daily variation...

  5. Temperature Histories in Ceramic-Insulated Heat-Sink Nozzle

    Science.gov (United States)

    Ciepluch, Carl C.

    1960-01-01

    Temperature histories were calculated for a composite nozzle wall by a simplified numerical integration calculation procedure. These calculations indicated that there is a unique ratio of insulation and metal heat-sink thickness that will minimize total wall thickness for a given operating condition and required running time. The optimum insulation and metal thickness will vary throughout the nozzle as a result of the variation in heat-transfer rate. The use of low chamber pressure results in a significant increase in the maximum running time of a given weight nozzle. Experimentally measured wall temperatures were lower than those calculated. This was due in part to the assumption of one-dimensional or slab heat flow in the calculation procedure.

  6. Monitoring of Double-Stud Wall Moisture Conditions in the Northeast

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation, Westford, MA (United States)

    2015-03-01

    Double-stud walls insulated with cellulose or low-density spray foam can have R-values of 40 or higher. However, double-stud walls have a higher risk of interior-sourced condensation moisture damage when compared with high-R approaches using exterior insulating sheathing. Moisture conditions in double-stud walls were monitored in Zone 5A (Massachusetts); three double-stud assemblies were compared.

  7. Insulated ECG electrodes

    Science.gov (United States)

    Portnoy, W. M.; David, R. M.

    1973-01-01

    Insulated, capacitively coupled electrode does not require electrolyte paste for attachment. Other features of electrode include wide range of nontoxic material that may be employed for dielectric because of sputtering technique used. Also, electrode size is reduced because there is no need for external compensating networks with FET operational amplifier.

  8. Transcription independent insulation at TFIIIC-dependent insulators.

    Science.gov (United States)

    Valenzuela, Lourdes; Dhillon, Namrita; Kamakaka, Rohinton T

    2009-09-01

    Chromatin insulators separate active from repressed chromatin domains. In yeast the RNA pol III transcription machinery bound to tRNA genes function with histone acetylases and chromatin remodelers to restrict the spread of heterochromatin. Our results collectively demonstrate that binding of TFIIIC is necessary for insulation but binding of TFIIIB along with TFIIIC likely improves the probability of complex formation at an insulator. Insulation by this transcription factor occurs in the absence of RNA polymerase III or polymerase II but requires specific histone acetylases and chromatin remodelers. This analysis identifies a minimal set of factors required for insulation.

  9. Wonderful Walls

    Science.gov (United States)

    Greenman, Jim

    2006-01-01

    In this article, the author emphasizes the importance of "working" walls in children's programs. Children's programs need "working" walls (and ceilings and floors) which can be put to use for communication, display, storage, and activity space. The furnishings also work, or don't work, for the program in another sense: in aggregate, they serve as…

  10. Ambiguous walls

    DEFF Research Database (Denmark)

    Mody, Astrid

    2012-01-01

    The introduction of Light Emitting Diodes (LEDs) in the built environment has encouraged myriad applications, often embedded in surfaces as an integrated part of the architecture. Thus the wall as responsive luminous skin is becoming, if not common, at least familiar. Taking into account how wall...

  11. Analytical and numerical modeling for the effects of thermal insulation in underground tunnels

    Institute of Scientific and Technical Information of China (English)

    Liu W.V.; Apel D.B.; Bindiganavile V.S.; Szymanski J.K

    2016-01-01

    The heat flow generated from the infinite rock mass surrounding the underground tunnels is a major cause for the increasing cooling demands in deep mine tunnels. Insulation layers with lower thermal con-ductivities on tunnel walls and roof ceilings are believed to supply a thermo-barrier for heat abatement. However, it is found that no systematic theoretical investigations were made to predict and confirm the effectiveness of underground thermal insulation. Specifically, investigations on the underground insula-tion problems involving heat flows through the semi-infinite hot rock mass and insulation layer were not sufficient. Thus, in this paper, the thermal characteristics, accompanied with heat flow through the semi-infinite rock mass and the insulation layer, were modeled by both analytical and numerical meth-ods with focus on underground mine tunnels. The close agreements between models have indicated that the thermal insulation applied on tunnel surfaces is able to provide promising heat abatement effects.

  12. 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.

  13. Guided Circumferential Waves in Layered Poroelastic Cylinders

    Directory of Open Access Journals (Sweden)

    Shah S.A.

    2016-12-01

    Full Text Available The present paper investigates the propagation of time harmonic circumferential waves in a two-dimensional hollow poroelastic cylinder with an inner shaft (shaft-bearing assembly. The hollow poroelastic cylinder and inner shaft are assumed to be infinite in axial direction. The outer surface of the cylinder is stress free and at the interface, between the inner shaft and the outer cylinder, it is assumed to be free sliding and the interfacial shear stresses are zero, also the normal stress and radial displacements are continuous. The frequency equation of guided circumferential waves for a permeable and an impermeable surface is obtained. When the angular wave number vanish the frequency equation of guided circumferential waves for a permeable and an impermeable surface degenerates and the dilatational and shear waves are uncoupled. Shear waves are independent of the nature of surface. The frequency equation of a permeable and an impermeable surface for bore-piston assembly is obtained as a particular case of the model under consideration when the outer radius of the hollow poroelastic cylinder tends to infinity. Results of previous studies are obtained as a particular case of the present study. Nondimensional frequency as a function of wave number is presented graphically for two types of models and discussed. Numerical results show that, in general, the first modes are linear for permeable and impermeable surfaces and the frequency of a permeable surface is more than that of an impermeable surface.

  14. UF{sub 6} cylinder fire test

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.H. [Oak Ridge K-25 Site, Oak Ridge, TN (United States)

    1991-12-31

    With the increasing number of nuclear reactors for power generation, there is a comparable increase in the amount of UF{sub 6} being transported. Likewise, the probability of having an accident involving UF{sub 6}-filled cylinders also increases. Accident scenarios which have been difficult to assess are those involving a filled UF{sub 6} cylinder subjected to fire. A study is underway at the Oak Ridge K-25 Site, as part of the US DOE Enrichment Program, to provide empirical data and a computer model that can be used to evaluate various cylinder-in-fire scenarios. It is expected that the results will provide information leading to better handling of possible fire accidents as well as show whether changes should be made to provide different physical protection during shipment. The computer model being developed will be capable of predicting the rupture of various cylinder sizes and designs as well as the amount of UF{sub 6}, its distribution in the cylinder, and the conditions of the fire.

  15. Dynamic Simulation of the Harvester Boom Cylinder

    Directory of Open Access Journals (Sweden)

    Rongfeng Shen

    2017-04-01

    Full Text Available Based on the complete dynamic calculation method, the layout, force, and strength of harvester boom cylinders were designed and calculated. Closed simulations for the determination of the dynamic responses of the harvester boom during luffing motion considering the cylinder drive system and luffing angle position control have been realized. Using the ADAMS mechanical system dynamics analysis software, six different arm poses were selected and simulated based on the cylinder as the analysis object. A flexible model of the harvester boom luffing motion has been established. The movement of the oil cylinder under different conditions were analyzed, and the main operation dimensions of the harvester boom and the force condition of the oil cylinder were obtained. The calculation results show that the dynamic responses of the boom are more sensitive to the luffing acceleration, in comparison with the luffing velocity. It is seen that this method is very effective and convenient for boom luffing simulation. It is also reasonable to see that the extension of the distance of the bottom of the boom is shortened by adjusting the initial state of the boom in the working process, which can also effectively reduce the workload of the boom—thus improving the mechanical efficiency.

  16. Flexural vibrations of finite composite poroelastic cylinders

    Indian Academy of Sciences (India)

    Sandhya Rani Bandari; Srisailam Aleti; Malla Reddy Perati

    2015-04-01

    This paper deals with the flexural vibrations of composite poroelastic solid cylinder consisting of two cylinders that are bonded end to end. Poroelastic materials of the two cylinders are different. The frequency equations for pervious and impervious surfaces are obtained in the framework of Biot’s theory of wave propagation in poroelastic solids. The gauge invariance property is used to eliminate one arbitrary constant in the solution of the problem. This would lower the number of boundary conditions actually required. If the wavelength is infinite, frequency equations are degenerated as product of two determinants pertaining to extensional vibrations and shear vibrations. In this case, it is seen that the nature of the surface does not have any influence over shear vibrations unlike in the case of extensional vibrations. For illustration purpose, three composite cylinders are considered and then discussed. Of the three, two are sandstone cylinders and the third one is resulted when a cylindrical bone is implanted with Titanium. In either case, phase velocity is computed against aspect ratios.

  17. Industrial thermal insulation: an assessment

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, R.G.; Tennery, V.J.; McElroy, D.L.; Godfrey, T.G.; Kolb, J.O.

    1976-03-01

    A large variety of thermal insulation materials is manufactured for application in various temperature ranges and environments. Additional and improved thermal insulation for steam systems is a key area with immediate energy conservation potential in several of the larger energy-consuming industries. Industrial thermal insulation technology was assessed by obtaining input from a variety of sources including insulation manufacturers, system designers, installers, users, consultants, measurement laboratories, open literature, and in-house knowledge. The assessment identified a number of factors relevant to insulation materials and usage that could contribute significantly to improved energy conservation.

  18. Flow interaction between a streamwise oscillating cylinder and a downstream stationary cylinder

    Science.gov (United States)

    Xu, S. J.; Gan, L.; Zhou, Y.

    2016-11-01

    In this paper, we present some experimental results about the physical effects of a cylinder's streamwise oscillation motion on a downstream one in a tandem arrangement. The upstream cylinder undergoes a controlled simple harmonic oscillation at amplitudes A/ d = 0.2-0.8, where d is the cylinder diameter, and the frequency ratio of f_e/f_s = 0-3.0, where f_e is the cylinder oscillation frequency and f_s is the natural frequency of vortex shedding from a single stationary cylinder. Under these conditions, the vortex shedding is locked to the controlled oscillation motion. Flow visualisation using the planar laser-induced fluorescence and qualitative measurements using hot-wire anemometry reveal three distinct flow regimes behind the downstream cylinder. For f_e/f_s > (f_e/f_s)_c, where (f_e/f_s)_c is a critical frequency ratio which depends on A/ d and Reynolds number Re, a so-called SA-mode occurs. The upstream oscillating cylinder generates binary vortices symmetrically arranged about the centreline, each containing a pair of counter-rotating vortices, and the downstream cylinder sheds vortices alternately at 0.5f_e. For 0.7-1.0 < f_e/f_s < (f_e/f_s)_c a complex vortex street that consists of two outer rows of vortices generated by the oscillating cylinder and two inner rows of vortices shed from the downstream stationary cylinder, which is referred to as AA-mode. For 0.3-0.6 < f_e/f_s< 0.8-1.0, one single staggered vortex street (A-mode) is observed. It is also found that, when f_e/f_s is near unity, the streamwise interaction of the two cylinders gives rise to the most energetic wake in the cross-stream direction, in terms of its maximum width, and the wake is AA-mode-like. The effects of other parameters such as the spacing between the two cylinders, Re and A/ d on the flow pattern are also discussed in details. The observations are further compared to the stationary tandem cylinder cases.

  19. Vortex noise from nonrotating cylinders and airfoils

    Science.gov (United States)

    Schlinker, R. H.; Amiet, R. K.; Fink, M. R.

    1976-01-01

    An experimental study of vortex-shedding noise was conducted in an acoustic research tunnel over a Reynolds-number range applicable to full-scale helicopter tail-rotor blades. Two-dimensional tapered-chord nonrotating models were tested to simulate the effect of spanwise frequency variation on the vortex-shedding mechanism. Both a tapered circular cylinder and tapered airfoils were investigated. The results were compared with data for constant-diameter cylinder and constant-chord airfoil models also tested during this study. Far-field noise, surface pressure fluctuations, and spanwise correlation lengths were measured for each configuration. Vortex-shedding noise for tapered cylinders and airfoils was found to contain many narrowband-random peaks which occurred within a range of frequencies corresponding to a predictable Strouhal number referenced to the maximum and minimum chord. The noise was observed to depend on surface roughness and Reynolds number.

  20. Sky reconstruction for the Tianlai cylinder array

    Science.gov (United States)

    Zhang, Jiao; Zuo, Shi-Fan; Ansari, Reza; Chen, Xuelei; Li, Yi-Chao; Wu, Feng-Quan; Campagne, Jean-Eric; Magneville, Christophe

    2016-10-01

    We apply our sky map reconstruction method for transit type interferometers to the Tianlai cylinder array. The method is based on spherical harmonic decomposition, and can be applied to a cylindrical array as well as dish arrays and we can compute the instrument response, synthesized beam, transfer function and noise power spectrum. We consider cylinder arrays with feed spacing larger than half a wavelength and, as expected, we find that the arrays with regular spacing have grating lobes which produce spurious images in the reconstructed maps. We show that this problem can be overcome using arrays with a different feed spacing on each cylinder. We present the reconstructed maps, and study the performance in terms of noise power spectrum, transfer function and beams for both regular and irregular feed spacing configurations.