Transfer Plate Research Articles

Shaking Table Test of a 1:20 Scale High-Rise Building with a Transfer Plate System

The reinforced concrete building considered in this study has 34 typical floors above a 2.7 m thick transfer plate and a three-level podium. The transfer plate is a reinforced concrete thick plate that transfers the loads from the walls at the typical floors to widely spaced columns in the three-level podium. A microconcrete model representing the high-rise building was constructed in 1:20 scale. Shaking table tests were conducted and the model was subjected to earthquake actions representing minor, moderate, major, and supermajor earthquakes for a region of moderate seismicity, with basic seismic intensity at the VIIth degree pursuant to GB50011-2001. Seismic performance was qualitatively assessed, and it is predicted that the prototype building will not collapse when subjected to major earthquakes. The majority of the damage and failure occurred at the story above the transfer plate. To minimize the damage, it is desirable to strengthen the walls between the 4th and 15th floors as well as reducing any change in stiffness within the transfer plate zone. Data obtained from the shaking table tests were analyzed. Spectral frequencies of the acceleration spectra estimated by the fast Fourier transform method and deformation measurements are good indicators on structural damage. Plots of acceleration against displacement would be useful in assessing the locations of structural damage. The use of the ratio of lateral stiffness to check the existence of a soft story may not be appropriate for high-rise buildings. However, story drift relates well with the degree of structural damage.

Improved Thick Plate Analysis and Design

Pile cap and transfer plate are typical thick plates requiring special care in analysis and design. From several real jobs in Hong Kong, the authors have discovered some limitations of the currentl...

Time-domain fluorescent plate reader for cell based protein-protein interaction and protein conformation assays

Fluorescence lifetime measurement is widely used in the biological sciences due to its inherent sensitivity and concentration independence. Frequency domain high-throughput plate readers and time-resolved energy transfer (TRET) plate readers are in common use and have been successful in a variety of applications ranging from basic biochemistry to drug discovery. Time-domain systems would have advantages due to their ability to distinguish both FRETing and non-FRETing populations, but have been difficult to develop due to inherent difficulties with background autofluorescence and lifetime component separation. Using a modified commercial lifetime plate reader, we demonstrate a method for removal of the complex auto-fluorescent background decay, described using a stretched exponential function (StrEF). We develop a generalized multi-exponential fitting algorithm (GeMEF), which progressively accounts for confounding lifetime components in FRET-based assays using a series of control experiments. We demonstrate the separability of FRET strength and efficiency and apply the technique to protein-protein interactions and protein conformational assays in a cell-based format. Presenilin 1 (PS1) is known to be important in Amyloid Precursor Protein (APP) processing in Alzheimer's disease. Using transfected cells, we demonstrate APP-PS1 interactions by FRET in a cell-based, 96-well plate format.

E112 鉛直二平板間密度成層内の自然対流熱伝達に及ぼす伝熱面間距離の影響(OS-10 自然対流および複合対流の伝熱・流動研究の新展開I)

E112 鉛直二平板間密度成層内の自然対流熱伝達に及ぼす伝熱面間距離の影響(OS-10 自然対流および複合対流の伝熱・流動研究の新展開I)

Investigating the use of cooling surfaces in solid‐state fermentation tray bioreactors: modelling and experimentation

AbstractThe effect of wall cooling in tray‐type solid‐state fermenters was investigated by cultivation of Aspergillus niger ATCC 10 864 on wheat bran. Temperature, moisture, pH and glucoamylase activity in the bed were monitored. Application of the heat exchanger plate reduced the overall water loss but increased the heterogeneity of moisture distribution in the bed. Moisture content increased markedly close to the heat transfer plate while the upper regions of the bed dried out. The thermal conductivity of the bed was measured to be 0.19 W m−1 K−1. At these conditions and depending on the air flow rate, 58–82% of the metabolic heat was removed via conduction towards the plate. A mathematical model was developed to describe the behaviour of the system. Model predictions were in good agreement with the experimental results. Diffusion coefficients of water vapour and oxygen in the bed were estimated to be around 1.3 × 10−5 m2 s−1 and 1 × 10−5 m2 s−1 respectively. Based on these values the mathematical model describes the way oxygen and water vapour diffusion influences biomass growth and moisture distribution in the bed. Copyright © 2004 Society of Chemical Industry

Heat transfer due to unsteadily impinging jets

In a systematic experimental study the heat transfer under three different periodically unsteady jets is compared to that of the corresponding steady inline jet. Unsteadiness of the jets is created by vortex shedding (Karman jet nozzle), alternating flow passages (flip–flop nozzle) as well as by a precessing motion of the whole jet (precessing jet nozzle). The unsteadiness of the jets is self-sustained, i.e., there are no external (mechanical) means and no external energy input to create unsteadiness. Heat transfer data in terms of Nusselt numbers are determined on a specially designed heat transfer plate in the plane of jet impingement. Whilst there is a slight increase in heat transfer performance when vortex shedding occurs within the jet (Karman jet nozzle), in both other cases there is a considerable decrease in heat transfer.

A model to predict erosion on mild steel surfaces impacted by boiler fly ash particles

Fly ash particles entrained in the flue gas from boiler furnaces in coal-fired power stations can cause serious erosive wear on steel surfaces along the flow path. Such erosion can, as a particular example, reduce significantly the operational life of the mild steel heat transfer plates that are used in rotary regenerative heat exchangers (‘air heaters’) that extract heat from the flue gas and transfer it to the incoming boiler combustion air. This paper describes research into fly ash impingement erosion on such surfaces. The effect of the ash particle impact velocity and impact angle on the erosive wear of mild steel surfaces, using three different power station ash types, was determined through experimental investigations. The experimental data were used to calibrate a fundamentally-derived model for the prediction of erosion rates. The model incorporates the properties of the ash particles and the target metal surface, as well as the characteristics of the ash particle motion in the form of the impingement velocity and the impingement angle. When tested using the three different types of ash, the experimentally-calibrated general model yielded results that generally differed by less than 15% from the values that had been measured experimentally.

Heat transfer under a precessing jet: effects of unsteady jet impingement

In a systematic experimental study the behaviour of a periodically precessing jet is compared to that of the corresponding steady inline jet. The precessing motion is that of self-sustained unsteadiness which is a consequence of an axisymmetric “Coanda-like” effect. The flow field is characterised by mean flow, turbulence and frequency data from hot wire measurements. Heat transfer data in terms of Nusselt numbers are determined on a specially designed heat transfer plate in the plane of jet impingement.

Analysis and behaviour of transfer plate–shear wall systems in tall buildings

AbstractSummaryThe current practice of design for a transfer plate–shear wall system in tall buildings does not generally include the interaction effect of the transfer plate and the supported shear walls on the structural behaviour of the system. As a result, it may lead to an unreasonable design for the internal forces of structural members and the corresponding steel reinforcement detailing. In this paper, analysis and structural behaviour of transfer plates supporting in‐plane loaded shear walls are presented, where emphasis is placed on the interaction between the transfer plate and the supported shear walls. The interaction effect is shown to cause significant stress redistributions both in the transfer plate and in the shear walls within an interactive zone. Parameters that influence significantly the structural behaviour and force transfer mechanism, such as the span–depth ratio of the transfer plate, the stiffness and locations of the shear walls, and the stiffness of support columns, are also highlighted. The paper is expected to provide not only a better understanding of the interactive characteristic of transfer plate–shear wall systems, but also a useful reference for the design of transfer plates supporting in‐plane loaded shear walls in tall buildings. Copyright © 2003 John Wiley & Sons, Ltd.

Heat transfer enhancement of dropwise condensation on a vertical surface with round shaped grooves

In dropwise condensation, the behavior of falling drops strongly affects the heat transfer. It is expected that the heat transfer during dropwise condensation would be enhanced if falling drops more frequently and widely sweep drops in the lower part. In this paper, we investigated heat transfer characteristics of dropwise condensation on the surface with grooves cut in a round shape. The heat transfer plate was made of copper with 30 mm square by 3 mm thick. The round shaped grooves were cut regularly on the surface. The plate was set vertically and the grooves were arranged in two positions, vertical and horizontal. The heat flux, surface temperature and sweeping cycle of falling drops were measured when steam flowed down and condensed on the grooved surface. As the results, it was found that the heat transfer on the vertical grooved surface was enhanced in the range of groove width from 2 to 3 mm. This indicated that the groove width of 2–3 mm was considered to be very effective in making falling drops sweep small droplets on the lower part of grooves.

Using microchannels to cool microprocessors: a transmission-line-matrix study

As microprocessors components density and clock frequency increase, so do heat dissipation. The heat results from Joule effect due to leakage currents in the components area or active region. This region is only few microns thick and can quickly reach destructing temperatures if heat is not quickly removed. On this critical issue depends the system reliability. The active region is separated from the ventilated heat sink by a silicon substrate and a metal integrated heat spreader, both hundreds of microns thick. This interface region is the microprocessor's heat transfer plate where heat exchange is achieved by conduction. Because of the localized heat source, the thermal spreading resistance of the interface region can be high. A novel way of spreading heat in that region is the use of microchannel arrays where an appropriate thermal compound or a phase change liquid can be trapped to increase heat transfer by conduction or to create micro-heat-pipes. Traditional cooling methods, with conventional and well optimised heat sinks, can then be used with less burden.In this paper, the Transmission-Line-Matrix (TLM) technique is used to simulate the effect of microchannels on the temperature distribution in the active region. To minimize the interface heat resistance various microchannel and patterns are examined. In this part of the work, the microchannels are filled with the heat spreader material copper or aluminium. The results show an improved thermal transient behaviour and a reduced active region temperature in steady state.

Modeling Stress Changes Induced by Earthquakes in the Southern Marlborough Region, South Island, New Zealand

Between 1888 and 1994 a series of seven earthquakes of M w 5.9-7.2 occurred within a 150 km by 150 km area (southern Marlborough region) directly east of the Alpine fault. Major strike-slip faults in this region, including the Hope, Kakapo, and Clarence faults, serve to transfer plate motion from the Alpine fault northeastward to the Hikurangi subduction zone. We have modeled induced changes in Coulomb failure stress (δCFS) to determine whether stress triggering could have occurred during this sequence and to determine how the earthquakes have affected stress along the North Westland segment of the Alpine fault, which appears to have last ruptured in this region in A.D. 1717. We included the effects of secular stress accumulation on the four most rapidly slipping faults in the region (Alpine, Awatere, Clarence, and Hope), but neglected the effects of viscoelastic relaxation. Our results suggest that at least six of seven earthquakes, and possibly all seven events (when uncertainties in earthquake location and focal mechanism are considered), occurred in regions where δCFS exceeded 10 kPa, indicating stress triggering may have occurred. Although δCFS exceeds 10 kPa along most of the North Westland segment of the Alpine fault at depths of 10 km or less, δCFS is less than 10 kPa at depths of 10 km or more. If rupture for large Alpine fault events initiates at depths of 10 km or more, then this result implies that the induced stress since 1848 has not brought this segment significantly closer to failure. Manuscript received 1 February 2001.

Enhancement of steam absorption into a film of LiBr aqueous solution falling over a downward‐facing plate

AbstractAn experimental study was performed on the enhancement of steam absorption into a LiBr aqueous solution. The enhancement method proposed here is to set an absorption heat transfer plate facing downward to generate free convection within a liquid film falling over the plate. The experiment was conducted varying the tilt angle of the heat transfer plate in a range of 40 to 90°. The heat transfer coefficients were compared for both cases of the heat transfer plate facing upward and downward. It was found from the experimental results that the downward‐facing plate has a higher heat transfer coefficient than the upward‐facing plate, which confirmed that free convection and mixing occur in the liquid film and enhance the absorption heat transfer in the case of the downward‐facing plate. The enhancement effect becomes remarkable as the tilt angle approaches horizontal, though the liquid film becomes thick and its thermal resistance increases. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(8): 606–616, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10062

Seismic assessment of transfer plate high rise buildings

The assessment of structural performance of transfer structures under potential seismic actions is presented. Various seismic assessment methodologies are used, with particular emphasis on the accurate modelling of the higher mode effects and the potential development of a soft storey effect in the mega-columns below the transfer plate (TP) level. Those methods include response spectrum analysis (RSA), manual calculation, pushover analysis (POA) and equivalent static load analysis (ESA). The capabilities and limitations of each method are highlighted. The paper aims, firstly, to determine the appropriate seismic assessment methodology for transfer structures using these different approaches, all of which can be undertaken with the resources generally available in a design office. Secondly, the paper highlights and discusses factors influencing the response behaviour of transfer structures, and finally provides a general indication of their seismic vulnerability. The representative Hong Kong building considered in this paper utilises a structural system with coupled shear walls and moment resisting portal-frames, above and below the TP, respectively. By adopting the wind load profile stipulated in the Code of Practice on Wind Effects: Hong Kong-1983, all the structural members are sized and detailed according to the British Standards BS8110 and the current local practices. The seismic displacement demand for the structure, when built on either rock or deep soil sites, was determined in a companion paper. The lateral load-displacement characteristic of the building, determined herein from manual calculation, has indicated that the poor ductility (brittle nature) of the mega-columns, due mainly to the high level of axial pre-compression as found from the analysis, cannot be effectively alleviated solely by increasing the quantity of confinement stirrups. The interstorey drift demands at lower and upper zones caused by seismic actions are found to be substantially higher than those arising from wind loads. The mega-columns supporting the TP and the coupling beams at higher zones are identified to be the most vulnerable components under seismic actions.

49.3: New Temperature and Heat‐Process Compensation System for a Tension Type CRT

AbstractNew concept of tension preservation and temperature compensating system is developed for a tension type CRT. Tension transfer plate (TTP) is used to store the tension energy of the mask during the heat‐process and the plate returns the stored energy back to the shadow mask to minimize the energy loss during the heat process. The plate also plays an important role in controlling temperature compensation of the mask in the normal operation condition, leaving possibilities for uni‐metal spring‐holder/ spring combination for the better performance under high‐low atmospheric temperature.

Thermodynamic optimisation in cryogenic insulation systems: dependence upon thermophysical conditions of the materials

The thermodynamic optimisation of one-dimensional cryogenic insulation systems where thermal conductivity depends upon temperature and other parameters has been studied. The following main different types have been considered for the general case of one-dimensional heat transfer (plate, hollow cylinder, and hollow sphere) and also for two-dimensional and three-dimensional heat transfer: (a) thermodynamic optimisation with a continuous variation of thermal flux along the insulation; (b) thermodynamic optimisation with a variation of thermal flux by finite steps along the insulation; (c) thermodynamic optimisation in two-layer or multilayer systems.

Natural convection in a vertical rectangular enclosure with localized heating and cooling zones

Experimental and numerical studies of natural convection in a single phase, closed thermosyphon were carried out using a vertical, rectangular enclosure model. Only one vertical plate plays the role of heat transfer surface having 100 mm height and 100 mm width, and others act as the adiabatic wall made of transparent plexi-glass. The heat transfer surface is separated into three horizontal zones with an equal height; top 1/3 and bottom 1/3 of the surface are cooling and heating zones, respectively and intermediate section is an adiabatic zone. Water is used as the working fluid. Variable parameters are distance D between the heat transfer surface and an adiabatic plate opposite to the heat transfer plate, and temperature difference ΔT between heating and cooling zones. By changing both D and ΔT, three regimes of the natural convection flow; quasi-two-dimensional steady, three-dimensional steady and unsteady flows are observed by means of thermo-sensitive liquid crystal powder and numerically simulated very well by solving a set of governing equations.

New developments in solid-state fermentation: II. Rational approaches to the design, operation and scale-up of bioreactors

Over the last decade there has been a significant improvement in understanding how to design, operate and scale-up solid-state fermentation bioreactors. The key to these advances has been the application of mathematical modeling techniques to describe the biological and transport phenomena within the system. This review focuses on the advances in understanding that have come from this modeling work, and the insights it has given us into bioreactor design, operation and scale-up. It also highlights two promising bioreactor designs that have emerged over the last decade or so. For processes in which the substrate bed must remain static throughout the fermentation, the most promising design is the Zymotis design of ORSTOM at Montpellier, France, which involves closely spaced internal heat transfer plates within a packed-bed bioreactor. For those processes in which mixing can be tolerated, the stirred bioreactor developed at INRA, in Dijon, France, has been successfully demonstrated at scales of 1–25 t of substrate. Theoretical work suggests that mathematical models will be useful tools in the scale-up process, however, there are no reports that they have been used in the development of any current large-scale process. Rather, the models have been validated against data obtained from laboratory-scale bioreactors. There is an urgent need to test the accuracy and robustness of the models by applying them within real process development.

Thermal design of an ultraslim notebook computer

We have developed two innovative thermal solutions for ultraslim notebook personal computer (PC) where only natural convection cooling can be used for heat rejection. The first solution is a cooling system for the CPU using the bottom chassis (Mg die-cast) as a heat spreader combining with Al heat transfer plate. The size and geometry were optimized by thermal analysis using finite volume method before making the prototype. As the second solution, a new coating which can reduce the warmth of Mg (magnesium alloy) die-cast enclosure has been developed and has already reached the stage of practical use. This paper describes the outline of these thermal design technologies used for Mitsubishi ultraslim notebook PC "Pedion." As of September 1997 "Pedion" was the world's thinnest at 18 mm thick among A4-size notebook computers for Microsoft(R) Windows(R).

BENDING PROPERTIES OF LAMINATED-LUMBER GIRDERS

Twenty-seven girders were built up from dimension lumber and tested to failure in bending. Each girderwas 7.9 m (26 ft) in length and contained three layers, with each of these layers comprised of stacked 38 140 and 38 235 mm (nominal 2 6 and 2 10 in.) members. Nails were used to join individual layers in 10 of the assemblies. Layersin the remaining assemblies were joined with shear transfer plates (STPs). One-half of the STP-laminated girders and allof the nail-laminated girders were loaded such that the top of the girder (a.k.a. edge A) was in compression. The otherhalf of the STP girders were turned upside-down and loaded such that the bottom of the girder (a.k.a. edge B) was incompression. Test results showed that the method of laminating (nails or STPs) did not significantly affect the bendingstrength nor the initial bending stiffness of the girders. Changing the surface of load application from edge A to edge Bdid not affect initial bending stiffness, but did have a significant affect on bending strength. This effect was attributed tothe differences in the tensile and compressive strengths of end-joint connections.