Showing papers on "Cavity wall published in 2008"

Analytical Evaluation of Via-Plate Capacitance for Multilayer Printed Circuit Boards and Packages

Abstract: The via-plate capacitance for a via transition to a multilayer printed circuit board is evaluated analytically in terms of higher order parallel-plate modes. The Green's function in a bounded coaxial cavity for a concentric magnetic ring current is first derived by introducing reflection coefficients for cylindrical waves at the inner and outer cavity walls. These walls can be perfect electric conductor (PEC)/perfect magnetic conductor(PMC) or a nonreflective perfectly matched layer. By further assuming a magnetic frill current on the via-hole in the metal plate, an analytical formula is derived for the via barrel-plate capacitance by summing the higher order modes in the bounded coaxial cavity. The convergence of the formula with the number of modes, as well as with the radius of the outer PEC/PMC wall is discussed. The analytical formula is validated by both quasi-static numerical methods and measurements. Furthermore, the formula allows the investigation of the frequency dependence of the via-plate capacitance, which is not possible with quasi-static methods.

A time-resolved particle image velocimetry investigation of a cavity flow with a thick incoming turbulent boundary layer

Abstract: The present paper aims for a better understanding of the flow in a rectangular cavity at very low Mach number and with a thick incoming turbulent boundary layer. In the present experiment the boundary layer is defined as thick because the ratio of the cavity length to the momentum thickness Θ is low (L/Θ=18) with respect to the claimed threshold (L/Θ>80) for cavity self-sustained oscillations to take place. Time-resolved particle image velocimetry (PIV) measurements were taken in planes normal and parallel to the wall over a cavity having aspect ratio L/H=4, at ReΘ=1041. The PIV data were analyzed to give the mean characteristics and the time behavior of the flow. The irregular vortex shedding observed in the shear layer was analyzed and interpreted with reference to the coherent structures in the incoming turbulent boundary layer. The unsteady load on the cavity walls and the consequent oscillating drag forces were studied by analyzing the instant momentum flux across the cavity mouth. A low frequency mo...

Influence of evaporation and seepage on the convergence of a ventilated cavity

Abstract: [1] In the design of nuclear waste disposals, an important topic concerns the development of an excavated damage zone, where permeability increases. A correct numerical prediction of the coupled processes occurring during excavation is therefore needed. In this paper, a nonclassical hydraulic boundary condition is described. It mixes two modes of water exchanges in partial saturation: seepage and evaporation flows. Seepage flow avoids unphysical water inflow into the rock mass, which might be obtained with usual boundary condition in dilatant geomaterial. Evaporation flows enable the thermodynamical equilibrium between air relative humidity in the cavity and in the rock mass. The numerical modeling of a cavity excavation in dilatant geomaterial is carried out. The results show the influence of the hydraulic boundary condition on the convergence of the cavity. Depending on the value of the transfer coefficient, the proposed numerical model can recover the results obtained with an imposed atmospheric pressure or suction at the cavity wall. The determination of the mass transfer coefficient is thus needed and can be achieved through drying experiments or can be estimated thanks to in situ measurements.

Anchors and reinforcements for masonry walls

Abstract: Anchor and reinforcement devices for a cavity wall are disclosed. The devices are combined with interlocking veneer anchors, and with veneer reinforcements to form unique anchoring systems. All the components of the system are wire formatives, including therewithin truss or ladder reinforcements and the eye extensions. The wall anchor portion of the device is fusibly attached to the exterior of the truss or ladder reinforcement by various metalworking techniques. Beyond the portions of the wire formatives inserted in the backup wall, the wire formatives are optionally reduced in height by cold-working thereof. The combined wall anchor and reinforcement devices are compressively reduced in height for spanning insulation mounted on the exterior of the backup wall. The low-profile portions are disposed between thick strips of insulation and maintain the insulative integrity thereof by preventing air leakage.

Testing Particulate Materials

Abstract: Embodiments include an apparatus and method for testing a particulate material suitable for use as a proppant. According to one embodiment, a sample of the particulate material is captured in the cavity of a test vessel between a cavity wall and a piston sealed with the cavity wall. A fluid is flowed into the test vessel from a fluid inlet of the test vessel to wet the sample of particulate material. The fluid is pressurized to a target fluid pressure greater than ambient pressure and heated to a target temperature greater than ambient temperature. The piston is moved into direct contact with the particulate material with sufficient force to crush at least a portion of the particulate material while maintaining one or both of the target temperature and the target pressure for one or more test cycles. Each test cycle has a duration of at least about 120 seconds and as long as about 24 hours.

Analytical prediction of the breakout noise from a rectangular cavity with one compliant wall

Abstract: This paper describes an analytical calculation of breakout noise by incorporating three-dimensional effects along with the acoustical and structural wave coupling phenomena. The breakout noise phenomena from cavities are important at low frequencies, and the coupling between acoustic waves and structural waves plays a critical role in prediction of the transverse transmission loss. The first step in the breakout noise prediction is to calculate the inside cavity pressure field and the normal cavity wall vibration by using an impedance-mobility approach, which results in a compact matrix formulation. The second step is to calculate the radiated sound power from an unbaffled plate formulation that poses formidable challenges on computational time. The proposed formulation helps in reducing the computational time substantially by converting quadruple integrals into single integrals using an appropriate coordinate transformation technique. Analytical results are validated with the finite element/boundary element numerical models.

Cladding system for buildings

Abstract: A cladding system, intended to exclude water from within a building having a cavity wall structure, includes passive means (a) for minimising any flow of water from the exterior that may reach the interior, and (b) open guides or enclosed channels for diverting such water so that it flows by gravity down the cavity to be drained outwardly. One implementation provides impervious battens modified to have water-diverting sides, and another provides solid slabs including channels connected by drainage cuts along their length to a surface to be drained.

Shallow-angle water entry of ballistic projectiles

Abstract: The water-entry of ballistic projectiles is investigated using high-speed digital imaging to capture the subsurface cavity dynamics. Specially designed 0.22 caliber projectiles are fired into water at shallow angles to the free surface (5 ◦ to 15 ◦ ) at Mach numbers between 0.3 and 1.0. Redesigned projectile tip geometries allowed projectiles to successfully enter the water and travel large distances underwater, due to the subsurface vapor-cavity that forms after impact, dramatically decreasing drag on the projectile. Projectile dynamics, critical entry angle and cavity formation are discussed for various bullet geometries, and results show that successful water-entry is a function of tip shape and length-to-diameter ratio. The data conclusively show that bullets with lower length-to-diameter ratios tumble inside the vapor cavity, while higher length-to-diameter ratios can lean against the cavity walls inducing a planing force pushing them back inside the cavity and mitigating the tumbling behavior. Experimental cavity observations of vapor-cavity formation is compared to a modified version of Logvinovich’s [1] theoretical model, which includes an updated formulation of the model and an angle of attack correction. Despite the unsteady nature of this problem, this improved steady state model fits well with experimental data and serves as an accurate design tool for naval engineers.

High-speed jet formation after solid object impact

Abstract: A circular disc hitting a water surface creates an impact crater which after collapse leads to a vigorous jet. Upon impact an axisymmetric air cavity forms and eventually pinches off in a single point halfway down the cavity. Two fast sharp-pointed jets are observed shooting up- and downwards from the closure location, which by then has turned into a stagnation point surrounded by a locally hyperbolic flow pattern. This flow, however, is not the mechanism feeding the jets. Using high-speed imaging and numerical simulations we show that jetting is fed by the local flow around the base of the jet, which is forced by the colliding cavity walls. We show how the well-known theory of a collapsing void (using a line of sinks on the symmetry axis) can be continued beyond pinch-off to obtain a new and quantitative model for jet formation which agrees well with numerical and experimental data

Aerothermal Investigation of a Rib-Roughened Trailing Edge Channel With Crossing Jets—Part II: Heat Transfer Analysis

Abstract: The present contribution addresses the aerothermal experimental and computational study of a trapezoidal cross-section model simulating a trailing edge cooling cavity with one rib-roughened wall and slots along two opposite walls. Highly resolved heat transfer distributions for the geometry with and without ribs are achieved using a steady state liquid crystals method in part II of this paper. The reference Reynolds number defined at the entrance of the test section is set at 67,500 for all the experiments. Comparisons are made with the flow field visualizations presented in part I of this paper. The results show the dramatic impact of the flow structures on the local and global heat transfer coefficients along the cavity walls. Of particular importance is the jet deflected by the rib-roughened wall and impinging on the opposite smooth wall. The experimental results are compared with the numerical predictions obtained using the finite volume, Reynolds-Averaged Navier–Stokes solver Calcul d'Ecoulements Diphasiques Reactifs pour l'Energetique (CEDRE ).

The water-entry cavity formed by low Bond number impacts

Abstract: We examine the evolution of the water-entry cavity formed by millimetric steel spheres with hydrophobic coatings striking the water surface. The impact creates an axisymmetric air cavity that expands radially before closing under the combined influence of hydrostatic pressure, surface tension, and dynamic pressure. At low Bond numbers, B = gR2 / 1, where R is the sphere radius, the liquid density, the surface tension, and g the gravitational acceleration, cavity collapse is driven primarily by surface tension and possesses features not readily observed at high Bond numbers, B 1, including longitudinal cavity ripples and multiple pinchoffs. The cavity evolution at Weber number, W= U2R / =110, B=0.088, corresponding to R=0.80 mm, U =310 cm /s is shown in Fig. 1. The time between successive images is 0.94 ms. Longitudinal ripples are observed to propagate down the cavity walls at speeds less than that of the sphere. The cavity pinches off approximately halfway between the free surface and the sphere. The vertical retraction of the upper cavity results in a Worthington jet, while the lower cavity oscillates while remaining attached to the sphere. The cavity evolution at W=420, B=0.14, corresponding to R=1.0 mm, U=540 cm /s is shown in Fig. 2. Images were captured above and below the free surface with two synchronized cameras. The time between successive images is 1.9 ms. The impact generates a splash curtain that falls inward, creating a dome that seals the cavity from above. Once the cavity is sealed, the cavity pressure decreases as the sphere descends and the cavity volume increases. Note the Rayleigh–Taylor instability that develops, leading to a jet that penetrates the cavity from above. Eventually, pinchoff occurs at depth; this process is repeated several times, with each successive pinchoff producing a bubble of progressively decreasing volume.

Assessing the benefits of cavity ventilation by hygrothermal simulation

Abstract: There is a controversy between Central Europe and North America concerning the necessity of back ventilating the exterior finishing layers of external wall structures. In the past, several European studies have proven that cavity walls are working as well or even better without back ventilation and it has now become common practice to omit the ventilation plane altogether. On the other hand, recent North American studies have confirmed the benefits of back ventilating the exterior stucco or brick veneer of wood frame walls. In order to solve this discrepancy a simple ventilation model has been implemented into a one-dimensional hygrothermal simulation tool and validated by comparison with experimental data. The simulation results help explain the different perceptions of the benefits of ventilation. Without ventilation an external wall may experience inward vapour drive after a rainy spell. This is generally no problem for a typical Central European wall structure made of masonry that can easily absorb a considerable amount of vapour without any risk of damage. However, it is important when the wall is composed of structural layers that are sensitive to moisture such as OSB or plywood sheathing which are often used in North American wall assemblies. Because the inward vapour drive is greater when the cladding is not ventilated the critical moisture content of the exterior sheathing may be exceeded without cavity ventilation.

A tunable cavity resonator with a temperature compensation plate comprising an aperture for the tuning member

Abstract: A TEM mode resonator comprising a tuneable cavity defined by an electrically conducting cavity wall, the cavity wall comprising a grounding face 15, a capacitor face 16 and a surrounding wall extending therebetween; an electrically conducting resonator member 18 within the cavity extending from the grounding face part way to the capacitor face; a tuning member 19 within the cavity between the resonator member and capacitor face adapted to be displaced towards and away from the capacitor face along a displacement axis to tune the resonator; the capacitor face further comprising an electrically conducting temperature compensation plate 25, the temperature compensation plate being connected to the capacitor face at two spaced apart points 23, 24 and forming a bowed surface therebetween; the temperature compensation plate having a smaller coefficient of thermal expansion than the capacitor face; characterised in that the temperature compensation plate comprises an aperture 26 being arranged such that on displacement of the tuning member towards the capacitor face the tuning member is displaced towards the aperture.

Study on Trough Receiver for Linear Concentrating Solar Collector

Abstract: In this paper, a trough black body cavity receiver for linear concentrating collector, which has potential application at moderate working temperatures (near 100°C) or higher temperature (above 180°C), has been studied. Four different shapes of the receiver have been proposed and tested. The optical efficiencies of the four receivers are simulated by using light tracking method. The thermal performances of the cavity receivers are tested under temperature levels, 90°C and 150°C, where the concentrated solar radiation is simulated by electric heating film. Both optical and thermal analysis illustrates that the triangle trough receiver is the best choice. To reduce the thermal losses, three kinds of glass cover are fixed on the cavity receiver. The thermal losses of the three different receivers with glass cover have been tested, when the inlet temperature varies from 35°C to 95°C. The experimental results indicate that the glass cover can reduce the thermal losses effectively. The semicircular cavity is tested in an linear concentrating solar collector, in which the sunlight is concentrated by a linear Fresnel lens(aperture width is 0.4m and optical efficiency is 0.7) and scatters on the semicircular cavity wall, absorbed by the copper tube and transmitted to working fluid. The highest average efficiency can reach 43% when the inlet temperature of the working fluid is 90°C. It is found from experimental results that the efficiency of this designed cavity receiver is a little lower than that of evacuated tube, but has good potential in application because it is cheap and can be manufactured easily.

Laser pulse heating and vapor front generation

Abstract: Laser nonconduction limited heating situation results in cavity formation and vapor front development above the cavity. As laser heating progresses, cavity wall recesses towards the solid bulk while the vapor front expands into its ambient due to recoil pressure generated at liquid-vapor interface in the cavity. To obtain velocity, temperature, and pressure fields in the evaporating front become challenging, since the process involves with transient evaporation of the surface during the absorption of the laser energy by the solid substrate. In the present study, phase change processes taking place in the substrate material during a laser heating process are modeled using an energy method and evaporating front behavior is modeled using the transient flow equations. Since the problem is involved with the multi-physics, the numerical technique is introduced to solve the resulting governing equations. The water ambient is assumed around the cavity in order to resemble the laser processing situation, particularly for laser shock processing. It is found that for nanosecond pulses with high intensity, the recession velocity of the surface reaches about 100 m/s at the symmetry axis and the recoil pressure of in the order of 10 GPa is generated in the cavity as a result of rapid evaporation. © 2008 American Institute of Chemical Engineers AIChE J, 2008

Molded polymeric drip edge

Abstract: A drip edge device is disclosed for use with the drainage system of a cavity wall structure. The drip edge device is disposed in the outer wythe, above the shelf angle or lintel, of a cavity wall structure extending the flashing and directing water and water vapor collected within the cavity wall to the weep holes and beyond the exterior surface of the outer wythe. The drip edge further allows for cavity wall ventilation. Removal of the water and the water vapor inhibits staining and material degradation. The drip edge device is a molded polymeric which withstands adverse environmental elements, including ultraviolet radiation. The drip edge device includes a peel-and-stick hot melt adhesive which, upon pressure activation, creates a durable bond with the rough surface of the masonry block or the flashing material. Optionally, a foam layer is placed on the lower surface of the drip edge.

Transfer molding mold, transfer molding device, resin molding method using the same, and semiconductor device

Abstract: PROBLEM TO BE SOLVED: To surely underfill a semiconductor device having a semiconductor chip mounted therein in a flip chip type and to form a fillet portion. SOLUTION: A configuration is employed wherein an air flow passage 70 is formed in an upper mold 20 and is directed from the upper mold 20 toward a lower mold 30 and a cavity wall 26 for forming a gate 16 and a cavity 50 is formed on a mold surface of the upper mold 20 and forms an inclined wall surface for expanding the cavity 50 toward a front end side and the air flow passage 70 is opened to a position outside a plane area of a semiconductor chip 64 of a semiconductor device 60 stored in the cavity 50. By switching an air supply/discharge state to a release film 80 sucked to the cavity wall 26 to switch a set state of the release film 80 in the cavity 50, the configuration allows a fillet portion 66 to be formed subsequently after a space between a wiring board 62 and the semiconductor chip 64 is filled with an underfill resin 90. COPYRIGHT: (C)2010,JPO&INPIT

Heat pipe type solar thermal-collecting tube

Abstract: The utility model relates to a heat pipe solar collector composed of an external sleeve and an internal heat pipe which is composed of a heat absorbing part integrated with a heat discharging part; the heat absorbing part thereof is installed in the external sleeve, the cross-section of which is an arc double-layer structure with a hollow cavity, while the heat discharging part thereof is fixed outside the external sleeve, and the internal heat pipe is connected in seal with the external sleeve; the internal heat pipe is installed between the outer wall of the external sleeve and the inner pipe cavity wall thereof in vacuum state; the outer surface of the heat absorbing part of the inner heat pipe is plated with solar absorbing coat; the inner cavity of the internal heat pipe is provided with a heat-conducting medium; the utility model saves raw material and energy with high heat efficiency and fast heat start, and no tube blasting occurs so that the collector does not have frost cracking in winter which is widely applied with constant heat conversion rate after long time use and high safety performance

Sandwich heat preserving wall body and building method thereof

Abstract: The invention relates to sandwich heat-preservation wall and a construction method thereof The heat-preservation wall consists of two layers of cavity wall which is brick-built by the internal and the external layers of masonry blocks; the heat-preservation layer is formed by insulation material by spot foaming The insulation foaming material can be urea formaldehyde foaming material or polystyrene foaming material or urea nitrogen foaming material or polyurethane foaming material The sandwich heat-preservation wall can improve wall heat-preservation performance, decrease production procedure, reduce production cost and waste, and meet the environment protection requirement for saving energy and reducing emissions

Expanding cavity adjustable exhaust silencer

Abstract: The invention discloses an exhaust muffler with an adjustable expanding cavity The exhaust muffler comprises an air inlet pipe, the expanding cavity and a vent-pipe; wherein the expanding cavity comprises a cavity wall, a front-end cover and a rear-end cover; a moving clapboard, which divides the expanding cavity into a cavity I and a cavity II, is arranged inside the expanding cavity; the cavity I is communicated with the cavity II by at least one resonant hole; an air outlet of the air inlet pipe and an air inlet of the vent-pipe are arranged inside the cavity I; the moving clapboard is provided with at least one elastic pretightening force device; the pretightening force direction of the elastic pretightening force device positively faces to the cavity I The exhaust muffler can realize self-adjustment of cavity volume and thus has the dynamic muffling effect that the muffling frequency of the muffler increases along with the increase of engine rotational speed and the muffling frequency of the muffler reduces along with the reduction of engine rotational speed, thereby realizing the low-frequency dynamic muffling The exhaust muffler has better low-frequency muffling effect, effectively eliminates the exhaust noise, also realizes the function of damping and reducing the exhaust pressure of the expanding cavity through the movement of the moving clapboard, and has simple and compact structure

Suspended tm mode dielectric combline cavity filter

Abstract: A combline filter has a ceramic resonator disposed inside at least one cavity wall. Because the resonator is implemented as a hollow rod, a tuning element may be inserted into an opening on the top of the rod to tune its frequency. A mounting element, inserted into an opening on the bottom of the rod secures its position inside a cavity resonator. Instead of soldering the resonator to the filter's walls, the resonator is supported above a bottom or side wall of the cavity resonator.

An in situ sealing method for liquid-filled micro-cavities based on photoembossing

Abstract: An in situ method for sealing an array of pre-filled micro-cavities, such as encountered in electrophoretic displays, is presented. The technique, which is based on photoembossing, forms a hermetic seal between the cover and the cavity walls. The seal locations are defined by ultraviolet exposure through a photolithographic mask, forming a latent image overlapping with the locations of the cavity walls. During a thermal development step, while the cover is mounted on top of the micro-cavities, the seal evolves and makes firm contact with the cavity walls. This technology is demonstrated to be insensitive to small deviations in cavity height, flatness of the cover and thin fluid films remaining between the cover and the top of the cavity walls. In the past, these aspects made it difficult to effectively seal large-area devices.

A tem mode resonator

Abstract: A TEM mode resonator comprising a tuneable cavity defined by an electrically conducting cavity wall, the cavity wall comprising a grounding face, a capacitor face and a surrounding wall extending therebetween; an electrically conducting resonator member within the cavity and extending from the grounding face part way to the capacitor face; a portion of the resonator member proximate to the capacitor face comprising a recess having an aperture therein; a tuning mechanism outside the tuneable cavity, the tuning mechanism comprising a tuning arm extending into the tuneable cavity through the aperture, the tuning mechanism being adapted to displace the tuning arm towards and away from the capacitor face, at least a portion of the tuning arm within the cavity being a tuning element, the tuning element being either a metal or a dielectric.

Terminal box in hollow photovoltaic curtain wall glass component

Abstract: The utility model discloses a junction box for a hollow photovoltaic curtain wall glass component The box body of the junction box is flat The bottom part of the box body is embedded with two positive and negative pole slices with shunt diodes The length direction of the bottom part of the box body is provided with two leading-in holes for an inner pole at two sides The inner cavity wall of the box body is provided with two clapboards provided with leading-out holes for an outer pole The two clapboards are respectively pressed on the positive and negative pole slices The pole slices are provided with a leading-out joint for the outer pole The junction box is concealed and arranged between the inner layer glass and the outer layer glass at the end part of the hollow photovoltaic curtain wall glass, thus improving the appearance of the photovoltaic curtain wall glass

Isothermal hot pressing board

Abstract: The utility model discloses an isothermal hot pressing plate. The technical proposal adopted by the utility model is as follows: a cavity is formed in the hot pressing plate, and a working medium and a heating device soaking in the working medium are arranged in the cavity. The working medium in the cavity is in a gas-liquid two-phase saturated state, the liquid-phase working medium is used for absorbing heat of the heating device and is boiled and gasified, and the gas-phase working medium releases heat to cavity walls and is condensed and liquefied. Accordingly, the working medium can continuously transfer heat released from the heating device to the cavity walls as the main body of the hot pressing plate. The heat absorbed and released by the working medium is phase-change latent heat, so that the temperature in the cavity is constant, thus achieving the constant temperature of the hot pressing plate. The isothermal hot pressing plate can be used for the hot pressing plate for an artificial board press, a copper clad laminate press, a thermo-setting resin decorative layer laminate press, a vacuum coating press, a positive and negative pressure film press, a flat vulcanizing machine, hot-pressing printing equipment and other hot presses.

Acoustic-electric transducer, electronic device, method, and computer program product

Abstract: An acoustic-electric transducer for a microphone may include a cavity delimited by a wall and having an opening; a diaphragm having an outer boundary, said diaphragm extending across said opening so that an air gap is provided transversely outwards of the diaphragm between said outer boundary of said diaphragm and said cavity wall; and an actuator configured to adjust a size of said air gap.