bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Surface-Micromachined Nitride-Diaphragm High-Pressure Sensor for Oil Well Application
Authors: Xu Yong , Jiang Fukang , Tai Yu-Chong , Donzier Eric , Loomis William A. , Liberman Arthur D. 
Published: November 2021

Abstract
A surface-micromachined, high-pressure sensor with polysilicon piezoresistors for oil well applications has been successfully developed. This work represents the first report of a nitride-diaphragm (3μm thick) oil-well pressure sensor with a diaphragm diameter of 44μm. The sensors have been calibrated up to 4000 psi. A sensitivity of 7.7 μV/V/psi is obtained. With 5 V excitation voltage, the full scale output (FSO, 4000 psi) is 154 mV. The nonlinearity is less than ± 0.2% of FSO. The hysteresis is less than 0.04% of FSO. A temperature coefficient of 25 μV/V/°C (equivalent to 0.08% of FSO/°C) is observed under 1000 psi pressure bias.
The Correct Treatment of Harmonic Pressure-Flow Behavior in Microchannels
Authors: Morris Christopher J. , Forster Fred K. 
Published: November 2021

Abstract
Advances in microfluidic technology give great potential for integrated systems with many components. Because continuum modeling is difficult even for simple systems, low-order modeling is essential to their design. Unsteady flow in microfluidic components such as channels and valves may require special treatment to achieve accurate low-order models of entire systems. One example is the fixed-valve micropump, in which the interaction between mechanical, electrical, and fluidic components produces maximum pump output at a resonant frequency near the corner frequency of the valves. In this frequency range the commonly-used value for fluid impedance was found to be in error by 30%, causing errors in predictions of pump membrane motion by as much as 300%. Proper treatment of the pressure-flow relations based on the exact solution of the Navier-Stokes equations for oscillatory flow corrected these deficiencies.
Microdegasser for HPLC Devices
Authors: Rummler Zeno , Berndt Manfred , Härtl Hans-Georg , Hempel Mario , Peters Ralf-Peter , Schomburg Werner K. 
Published: November 2021

Abstract
The market of chemical analysis calls for more sensitive devices which are able to analyze very small sample volumes of only a few nanoliters in a very short time. Therefore, devices are required, which contain components with microscopic dimensions. Such micro devices can be fabricated with the AMANDA process.
This paper describes a microdegasser for high performance liquid chromatography (HPLC), which was developed in a cooperation of Agilent Technologies, Forschungszentrum Karlsruhe (Karlsruhe Research Center), and STEAG microParts and is manufactured now by STEAG microParts. The microdegasser is one of the components, which help the new generation of HPLC devices of Agilent Technologies to achieve their excellent market position.
On a Constitutive Model for Twisted Hybrid Yarns
Authors: Godfrey Thomas A. , Rossettos John N. 
Published: November 2021

Abstract
A simple micromechanical model is developed for the interactions in a parallel square-stacked mixed array of elastic fibers representing the microstructure of a hybrid yarn undergoing axial extension. The mixed array consists of a small fraction of relatively high-modulus, low-elongation-to-break (LE) fibers dispersed among high-elongation-to-break (HE) fibers. The LE fibers are assumed to break into fragments, and the LE fiber fragments are assumed to slip relative to neighboring fibers in regions near the fragment tips. The fiber array experiences lateral compression arising from the remote tension on the twisted yarn, and frictional forces acting at slipping fiber-to-fiber contact surfaces are assumed to obey Amontons’ Law. Solutions of a dimensionless boundary value problem for deformations in a unit cell of the fiber array are presented. Dimensionless parameters involving the constituent LE and HE fiber properties are identified and their influence on hybrid yarn tensile behavior is illustrated.
New Frontiers in Enhanced Heat Transfer
Authors: Bergles Arthur E. 
Published: November 2021

Abstract
This review paper considers the many techniques that have been developed to enhance convective heat transfer. A summary is given of the techniques that are effective for the various modes of heat transfer. Of particular interest currently is compound enhancement that involves the simultaneous application of several techniques, so as to produce an enhancement that is larger than the individual techniques operating separately. There are many experimental and analytical challenges that relate to obtaining and applying data. The current advanced enhancement represents 3rd generation heat transfer technology. This technology will find increasing application in all industries.
Heat Transfer Enhancement for Finned-Tube Heat Exchangers With Winglets
Authors: O’Brien James E. , Sohal Manohar S. 
Published: November 2021

Abstract
This paper presents the results of an experimental study of forced convection heat transfer in a narrow rectangular duct fitted with a circular tube and/or a delta-winglet pair. The duct was designed to simulate a single passage in a fin-tube heat exchanger. Heat transfer measurements were obtained using a transient technique in which a heated airflow is suddenly introduced to the test section. High-resolution local fin-surface temperature distributions were obtained at several times after initiation of the transient using an imaging infrared camera. Corresponding local fin-surface heat transfer coefficient distributions were then calculated from a locally applied one-dimensional semi-infinite inverse heat conduction model. Heat transfer results were obtained over an airflow rate ranging from 1.51 × 10−3 to 14.0 × 10−3 kg/s. These flow rates correspond to a duct-height Reynolds number range of 670–6300 with a duct height of 1.106 cm and a duct width-to-height ratio, W/H, of 11.25. The test cylinder was sized such that the diameter-to-duct height ratio, D/H is 5. Results presented in this paper reveal visual and quantitative details of local fin-surface heat transfer distributions in the vicinity of a circular tube, a delta-winglet pair, and a combination of a circular tube and a delta-winglet pair. Comparisons of local and average heat transfer distributions for the circular tube with and without winglets are provided. Overall mean fin-surface Nusselt-number results indicate a significant level of heat transfer enhancement associated with the deployment of the winglets with the circular cylinder. At the lowest Reynolds numbers (which correspond to the laminar operating conditions of existing geothermal aircooled condensers), the enhancement level is nearly a factor of two. At higher Reynolds numbers, the enhancement level is close to 50%.
Measurements of Property Data for LiNO3,KNO3,NaNO3-H2O Mixture
Authors: Andersen Jens Møller , Costa Andrea , Ziegler Felix 
Published: November 2021

Abstract
Construction and simulation of high temperature absorption systems need good property data. At the moment a mixture of LiNO3,KNO3,NaNO3-H2O is among few non-corrosive working-pairs for absorption systems working above 160°C. The properties of this mixture have been published by Erickson in 1986 but these data only represent some concentrations and a part of the temperature pressure field. If this nitrate mixture should be used for an absorption machine generating steam at 150 °C or as a topping cycle to a 2-effect libr cycle, the data are insufficient. The measurements presented in this article validate and extend the Erickson property data. And a more precise and detailed detection of the crystallisation behaviour is presented. Furthermore, it is seen that the solution has a tendency to deviate from the expected Temperature Pressure relation. Finally methods for estimation of the concentration are discussed.
Inverse Solution of Radiative Heat Transfer in Two-Dimensional Irregularly Shaped Enclosures
Authors: Ertürk Hakan , Ezekoye Ofodike A. , Howell John R. 
Published: November 2021

Abstract
An inverse solution technique is used to predict the necessary temperature and heat flux distributions of the heater section of a two-dimensional enclosure so the heater satisfies the specified heat flux and temperature distributions of design surfaces, while satisfying one thermal boundary condition for the other walls. Radiation is the dominant mode of heat transfer in systems where high temperatures are present; therefore, it is considered as the only mode of heat transfer in this study. The two-dimensional enclosures considered in this study are made up of straight segments, positioned so that they form irregularly shaped enclosures approximating situations for many of the real cases in industrial applications. The enclosure walls are gray, emitting diffusely and reflecting either diffusely or specularly. The medium inside the enclosure may be transparent, absorbing-emitting or absorbing-emitting and isotropically scattering. For the participating medium cases, the gray medium is considered as isothermal, homogeneous and isotropically scattering. The Monte Carlo method is used for formulation of radiative heat transfer. The method is preferred for its accuracy and ease of handling complex geometries and various surface and medium properties. The main contribution of this study is to solve inverse design problems for complex geometries that contain blockage and shading effects, as could be the case in many real industrial applications. The resulting system of equations, which includes Fredholm equations of the first kind, is known to be highly ill-conditioned in nature. The solution for this ill-conditioned system is handled by the conjugate gradient method, an iterative solution method, which obtains smooth and very accurate solutions in a few steps for linear systems.
A Monte Carlo Study of the Transient Radiative Transfer Within the One-Dimensional Multi-Layered Slab
Authors: Sawetprawichkul A. , Hsu P.-F. , Mitra K. , Sakami M. 
Published: November 2021

Abstract
Short pulse lasers are considered a useful tool for material processing and diagnostics. Only recently, fundamental understanding of the pulse laser interactions with materials gained much attention. The analysis of the underlying process involves solving the transient radiative transfer equation, which is very challenging, and most prior work relied on the approximate models. In this paper, a time-dependent Monte Carlo method is used to study the transient radiative transfer within the nonhomogeneous absorbing and scattering media. The Monte Carlo results compared very well with the accurate deterministic models and such comparisons have been lacking in many prior Monte Carlo studies.
The problem of interest has one-dimensional multi-layered slab geometry. Two different media are examined; a two-layer slab with different absorption and scattering coefficients in each layer; and a three-layer medium with different scattering albedo in the mid-layer. The temporal spreads of the transmittance and reflectance of a pulsed, collimated incident beam are obtained. The photon propagation across the interface and the resultant output radiative signatures due to the layered properties are discussed in detail.
Measurement and Prediction of the Contact Conductance Across Epoxied Copper Contacts at Cryogenic Temperatures
Authors: De Bellis Lisa , Phelan Patrick E. 
Published: November 2021

Abstract
Literature has demonstrated that the investigation of the contact conductance (hc) across epoxied joints at cryogenic temperatures is important to the microelectronic, satellite and other space industries. The accurate theoretical prediction of the hc arising across a metal-epoxy interface is still being researched. Several researchers have shown that the acoustic mismatch and other theories do not agree well with experimental data. This paper presents the results of an experimental and theoretical investigation of the hc across copper/epoxy/copper contacts. From the hc data, it was possible to extract the thermal conductivity (k) of the epoxy and the thermal boundary resistance (Rb) between the epoxy and copper. The Rb extracted from the experimental data was compared to model predictions made by the Acoustic Mismatch Model (AMM) and the Scattering Mediated Acoustic Mismatch Model (SMAMM). In the case of the AMM, the predictions underestimated the experimental values significantly. This finding is consistent with many investigations to date. The SMAMM was able to predict the experimental data very well when using an extremely small scattering time of 5×10−18 s.
Flow Characteristics in Convective Melting of a Solid Particle in a Fluid
Authors: Hao Y. L. , Tao Y.-X. 
Published: November 2021

Abstract
Flow visualization based on the particle image velocimetry (PIV) technique is conducted to quantitatively investigate the flow around a melting ice sphere in horizontally flowing water. The distributions of velocity, streamtrace, and vorticity around the ice sphere are obtained for different upstream velocities and temperatures. General flow characteristics around the melting ice sphere and effects of velocity and temperature are analyzed. The visualization of melting of a dyed ice sphere is also conducted to qualitatively investigate the motion of the melt and the mixing with mainstream. The original experimental results are published to serve as benchmark data for numerical model development.
Critical Heat Flux in Heated Horizontal Thin Annuli
Authors: Stoddard R. M. , Dowling M. F. , Abdel-Khalik S. I. , Ghiaasiaan S. M. , Jeter S. M. 
Published: November 2021

Abstract
The objectives of the work reported here were to experimentally study the critical heat flux in a heated thin, horizontal, annular flow passage cooled by subcooled water and to examine the applicability and relevance of the current predictive methods for critical heat flux to such passages. Experiments were performed in the Georgia Tech Microchannel Test Facility (GTMTF). The test section was an annulus with 6.45 and 7.77 mm inner and outer diameters, respectively (0.66 mm gap width), and an 18.5-cm long heated section. The experimental parameters investigated covered the following ranges: test section exit pressure: 0.344–1.034 MPa; coolant (water) mass flux: 100–380 kg/m2s; wall heat flux: 0.231–1.068 MW/m2; water inlet temperature: 30–65°C.
The results, in agreement with the existing CHF data for large horizontal channels, indicated that CHF values were considerably lower than the expected CHF values for vertical test section configuration. In all the tests CHF occurred at relatively high equilibrium qualities, and was preceded by flow stratification which caused dryout of the upper surface of the flow channel. The data were correlated by introducing empirical correction multipliers into three widely-used correlations for vertical channels, and based on the compensated distortions method.
Heat Transfer and Pressure Drop of CO2 Flow Boiling in Microchannels
Authors: Zhao Yuan , Molki Majid , Ohadi Michael M. 
Published: November 2021

Abstract
An experimental investigation was performed to study the flow boiling heat transfer of CO2 in microchannels. Tests were conducted in a horizontal triangular microchannel with the hydraulic diameter of 0.86 mm. Heat to the test section was provided by direct electrical heating. Experiments were conducted with CO2 at saturation temperatures of 273 to 293 K, mass fluxes of 100 to 820 kg/m2s, heat fluxes of 3 to 23 kW/m2, and qualities of 20% to 85%. It was demonstrated that heat flux had an enhancing effect on the heat transfer coefficient, while mass flux had a negligible effect. Nucleate boiling mechanism is found to be the dominant factor for CO2 flow boiling in microchannels. Heat transfer coefficient degraded quickly at high vapor quality region (0.6–0.7), which is possibly due to flow mal-distribution. Pressure drop increases slightly with vapor quality and/or heat flux. Mass flux has a strong increasing effect on pressure drop.
Design of a High Performance Cryocooler for Propellant Liquefaction and Storage on Mars
Authors: Zhou Lei , Kapat J. S. , Chow L. C. , Lei S. Y. 
Published: November 2021

Abstract
Human exploration of space is extending beyond low earth orbit and Moon as NASA is planning a human mission to Mars in 2014. Past studies indicate that In Situ Propellant Production (ISPP) on Mars is a key enabling technology in Mission to Mars. In ISPP, oxygen and methane, which are to be used as cryogenic propellants for any return vehicle from Mars to Earth, are produced on the Martian surface. Once the propellants are produced in gaseous state, they must be liquefied for storage and use in the ascent vehicle. Cryogenic cooling is needed for both liquefaction and storage since the storage temperature, around 90K for oxygen and 112K for methane, are considerably lower than the average temperature on the Martian surface, which is around 220K.
This paper presents the preliminary design of a single-stage, lightweight and compact, cryocooler based on reverse Brayton cycle with performance comparable to, but more reliable than, a corresponding Stirling cycle. With the application of micro-scale highly-effective recuperative heat exchanger, the estimated COP of the miniature cryocooler can reach 0.2. Thermal cycle parameters that can influence the cycle performance are studied. The two key enabling components, an integrated and micro-fabricated compressor and motor and a micro-fabricated recuperative heat exchanger, are discussed and shown to be possible with modern technology.
Analysis of Fin-Tube Evaporator Performance With Limited Experimental Data Using Artificial Neural Networks
Authors: Pacheco-Vega Arturo , Sen Mihir , McClain Rodney L. 
Published: November 2021

Abstract
In the current study we consider the problem of accuracy in heat rate estimations from artificial neural network models of heat exchangers used for refrigeration applications. The network configuration is of the feedforward type with a sigmoid activation function and a backpropagation algorithm. Limited experimental measurements from a manufacturer are used to show the capability of the neural network technique in modeling the heat transfer in these systems. Results from this exercise show that a well-trained network correlates the data with errors of the same order as the uncertainty of the measurements. It is also shown that the number and distribution of the training data are linked to the performance of the network when estimating the heat rates under different operating conditions, and that networks trained from few tests may give large errors. A methodology based on the cross-validation technique is presented to find regions where not enough data are available to construct a reliable neural network. The results from three tests show that the proposed methodology gives an upper bound of the estimated error in the heat rates.
The Development of a Neural Network Based System for the Optimal Control of Chain-Grate Stoker-Fired Boilers
Authors: Chong A. Z. S. , Wilcox S. J. , Ward J. 
Published: November 2021

Abstract
A novel Neural Network Based Controller (NNBC) was developed following a comprehensive set of experiments carried out on a pilot-scale stoker test facility at CRE Group Ltd., U.K. The NNBC mimicked the actions of an expert boiler operator, by providing ‘near optimum’ settings of coal feed and air flow, as well as ‘staging’ these parameters during load following conditions, before fine tuning the combustion air under quasi-steady-state conditions. Test results from the online implementation of the NNBC have demonstrated that improved transient and steady-state combustion conditions were attained. The prototype NNBC thus provides both stoker manufacturers and users with a means of reducing pollutant emissions, as well as improving the combustion efficiency of this type of coal firing equipment.
Experimental and Numerical Study of Transport Phenomena in a Simulated Hydrothermal Crystal Growth System of Fluid-Saturated Porous Layer
Authors: Mishra D. , Pal A. , Nemick N. , Saha A. K. , Prasad V. , Zhang H. 
Published: November 2021

Abstract
A simulated, non-pressurized hydrothermal system consisting of a fluid-superposed porous layer is fabricated and used for visualization and measurement of the temperature field using liquid crystal thermography. The system is used for various boundary conditions with pure glycerine as the working fluid and the porous layer is made of 3mm diameter glass beads. Experimental data is recorded using a color CCD camera and flow visualization is obtained through a long exposure video photography. A calibration is performed to relate the temperature with scattered colors at an orthogonal angle to the incoming white light sheet. Quantitative temperature data is obtained through this calibration and compared with the numerical predictions. For numerical studies the system is modeled as a composite layer of fluid and porous charge using the Darcy-Brinkman-Forchheimer flow model. A two-dimensional curvilinear algorithm using finite volume technique with a non-staggered grid is used to simulate the temperature field and transport phenomena for various Rayleigh–Darcy number combinations of varying aspect ratio. The results, for the first time, make an attempt towards understanding the transport process in hydrothermal system through both numerical simulation and experimental validation.
Electrohydrodynamic (EHD) Flow and Convective Boiling Augmentation in Single-Component Horizontal Annular Channels
Authors: Cotton James S. , Chang JenShih , Shoukri Mamdouh , Smith-Pollard Tracey 
Published: November 2021

Abstract
In order to explore the mechanics of EHD induced flow and heat transfer augmentation, an experimental study of the tube-side boiling heat transfer of refrigerant HFC-134a has been conducted in a single-pass, counter-flow heat exchanger. The electrode position was arranged concentric to the tube. Experiments are conducted for inlet qualities of 0% to 60%, mass fluxes from 100 kg/m2s to 500 kg/m2s, heat fluxes of 10 kW/m2 and 20 kW/m2, and applied voltage from 0 kV to 8 kV DC. The threshold of EHD effects were analysed by a proposed dimensional analysis which predicts that the EHD forces become significant when the Dielectric Electric Rayleigh number is of the same order of magnitude as the square of the liquid Reynolds number, Eℓε ≈ Re ℓ 2 . This criterion is supported by experimental evidence. Flow visualization experiments have shown that, when the proposed dimensionless criterion is satisfied, EHD body forces may have a strong influence on the liquid-phase and consequently the flow pattern within the channel. The various flow configurations clearly affect heat transfer and pressure loss and need to be considered in any attempt to identify the effects of an applied electric field.