bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three-Dimensional Imaging of Microfluidic Mixing Surfaces Using Dual-Channel Confocal Microscopy
Authors: Peach John P. , Hitt Darren L. , Dunlap Christopher T. 
Published: November 2021

Abstract
In the present study, we report on an experimental technique which enables the three-dimensional imaging and reconstruction of the microfluidic mixing surface — and the entire flow volume — at a 90° flow branch formed between converging Newtonian fluids of differing flow rate and viscosity. Only steady-state flows are examined. The technique involves the use of dual-channel laser scanning confocal microscopy (LSCM) and represents a significant extension of the technique previously introduced by Hitt & Lowe [1].
Energy Optimized Valve With Low Leakage Rates
Authors: Strobelt T. , Willmann M. , Kohnle J. , Waibel G. , Sandmaier H. , Zengerle R. 
Published: November 2021

Abstract
In our paper we report on piezo actuated valves with low leakage rates (&lt;10 nl/min). The valves are made by silicon/glass and plastics. They are adapted to real, battery driven applications in medical systems and consumer products. Therefore the valves have to be optimized to extremely low energy consumption.
Development of Particle Methods for Computing MEMS Gas Flows
Authors: Sun Quanhua , Boyd Iain D. , Fan Jing 
Published: November 2021

Abstract
The development of particle methods to simulate flows related to micro-electro-mechanical systems is described. This effort is aimed at increasing our understanding of rarefied gas behavior to facilitate the design and optimization of micro-devices. The proposed information preservation method preserves macroscopic information of the flow as the particles move and interact with each other and the domain boundaries. The results exhibit very low levels of statistical scatter, which helps apply the method to low speed MEMS flows. In the implementation, specific consideration is needed for flows with large temperature variation.
Micro Protein Arrays Prepared by Microfabricated Stamps
Authors: Tseng F. G. , Huang H. M. , Liu C. S. , Huang C. Y. , Lin S. C. , Chieng C. C. 
Published: November 2021

Abstract
A novel protein arraying method is proposed by utilizing micro stamps to spot proteins on a bio-absorption surface. The method can pick up various protein solutions to spot onto a desired substrate for protein immobilization. The fabrication process of the micro stamp combines surface micromachining and molding process. Successful transfer of BSA protein solution onto a PVDF (Polyvinylidene difluoride) surface has been demonstrated by using the micro fabricated stamps. The size of stamped protein spot in this stage is about 20–50% larger than that of the stamp. To quickly verify the protein binding ability to two different substrates: PVDF and PhastGel® Pad, a chopstick system is used to pickup protein solution for stamping. Result shows that appreciable amount protein retention is achieved for at least 6 hours on both substrates. Improved spotting size and position control on micro stamping process has also been carried out by stamp surface coating with aluminum/aluminum oxide and stamp picking up protein-solutions from a protein-solution pre-wetted clean room tissue.
Trends and New Paradigms in Electronics Cooling Market and Industry
Authors: Copeland David 
Published: November 2021

Abstract
Cooling technology for modern servers, workstations and desktop computers has just begun a period of rapid change. As processor powers approach 100 watts, longstanding limits on air cooling are being challenged. The most recent changes are in the heatsinks themselves, as the longstanding manufacturing process of extruding is no longer capable of meeting new performance requirements.
This study focuses on the history of creating an effective organization for bringing the skive heatsink to market, concentrating on development of a start-up unit within the company and a host of relationships, both technical and business, outside the company. Metals companies in Japan have long been accustomed to the necessity of constant innovation. Heatsinks fall into the vague category of a semi-custom product — each customer has almost the same requirements, with slightly different exceptions to a standard part. Additionally, a product lifetime may be measured in months rather than years.
In heatsinks, the high thermal conductivity, low density and low material cost of aluminum preclued serious competition from other materials. The computer market is dominated by large players but the size distribution tails off very slowly. 51% of the market is held by 6 companies, the largest with 14%. The remaining 49% features a wide distribution of market share and technical capabilities. This results in some customers with large staffs specializing in cooling technology, others with a small number (sometimes 1) of multidisciplinary mechanical/thermal engineers, and others with no engineering staff other than system integrators.
The presence of other materials is increasing, as heatsinks for the highest power processors will soon need copper bases and, ultimately, two-dimensional heatpipes known as vapor chambers. This integration of components represents a significant departure from the previous norm of attaching a one-dimensional tube heatpipe to an all-aluminum heatsink. In some cases ownership of development and production is the responsibility of the heatsink maker, in other cases the heatpipe or, in the case of an integrated cooling fan, the fan maker.
In order to address this wide and rapidly moving market, we have made alliances with makers of other electronics cooling components (fans, plastic housings, thermal interface materials), jointly developed products with computer and processor makers, and co-sponsored university research. This year (2000) saw a large-scale entry into the Gigahertz processor cooling market, with a focus on high level visibility at technical conferences and trade shows. As thermal concerns move from a final step in the design cycle to a initial consideration, educating customers about the potential contributions of the skive heatsink has become a major effort in our technical marketing campaign.
Assessment of Damage in Heterogeneous Concrete Composites
Authors: Smolarkiewicz Pawel P. , Willam Kaspar J. 
Published: November 2021

Abstract
Ultrasonic testing provides non-destructive measurements, which are widely used to evaluate stiffness degradation in materials and structures. In a recent study, a computational simulation method was developed for modeling ultrasonic pulse propagation in heterogeneous concrete materials. This method is based on a two-phase finite element model of the particle composite consisting of linearly elastic aggregate inclusions and a cement matrix, the damage of which is assessed via dynamic wave transmission analogous to ultrasonic testing. The advantage of this approach is its ability to examine the heterogeneous meso-structure and the progressive degradation of the elastic stiffness properties of the cement matrix. Although it proved very informative to simulate the ultrasonic response in coarse concrete mixes, it is unfortunately computationally very demanding because of the high mesh resolution necessary in space and time. The question arises, whether a simpler, less expensive method based on homogenized effective stiffness properties can provide comparable results. It is the objective of this paper to show, that, in fact, the resolution of the heterogeneities is necessary, and that the use of homogenized concrete properties cannot provide the information when progressive degradation is considered in the cement matrix which magnifies the contrast of the heterogeneous meso-structure.
PEDSS: A Product Engineering Decision Support System
Authors: Wang Nanxin , Becker Beverly , Kaepp Greg 
Published: November 2021

Abstract
Automotive vehicle body structure design is a long and complex design process. It involves iterations of design modifications, analysis, validation, and confirmation. It is time consuming and costly. In order to bring better and more affordable vehicles to the consumers, the auto-industry is seeking ways to reduce the vehicle cycle time and, at the same time, improve vehicle quality. One approach is to maximize the reuse of the engineering knowledge and make smart engineering decisions early. To assist engineers making decisions in the early design cycle, a Ford team has been working on the development of an intelligent vehicle Product Engineering Decision Support System called PEDSS. PEDSS is a knowledge based design tool that performs trade-off studies among various performance requirements, design specifications, package and manufacturing constraints, serviceability, and cost. It is developed using JAVA, JESS — a Java AI shell, and CORBA. It has been integrated with the company’s CAD system: IDEAS and applied to a small vehicle segment platform design.
Study of Dynamic Properties of Automotive Hydrobushing
Authors: Lu Min , Ari-Gur Judah 
Published: November 2021

Abstract
The objective of this research is to understand the dynamic properties of the hydrobushing. By means of a proposed mathematical model, it is found that the dynamic stiffness and loss angle of a hydrobushing are related to the rubber property and the effectiveness of the fluid in the inertia track. At high frequencies, however, the fluid in the inertia track becomes inefficient so that it may be ignored. It is also concluded that the rubber damping has minimal effect on the hydrobushing dynamic properties and may be neglected. The maximum loss angle of a hydrobushing, which corresponds to the maximum damping coefficient, occurs at a frequency close to the fluid resonant frequency. The degree of its closeness depends on the damping ratio and dynamic stiffness ratio.
Neural Network Based Automotive Clutch Model for Dynamic Engagement Analysis With Variable Time Steps
Authors: Cao M. , Wang K. W. , Fujii Y. , Tobler W. E. 
Published: November 2021

Abstract
The lubricated clutch in an automatic transmission plays an important role in the performance and comfort of passenger vehicles. Therefore, an accurate and easy-to-implement dynamic clutch model is necessary for powertrain system design and performance studies. A neural network approach recently developed by Parvataneni et al. [1999] for clutch modeling has illustrated some very promising results. However, this model has complex architecture that may cause slow training and testing. Also, due to the lack of time information, the network cannot adapt to time step variations. Therefore, it cannot be easily integrated with powertrain system models, which in general require variable time steps for a superior numerical integration performance. In this paper, a new first-principle-based hybrid network clutch model is derived for dynamic engagement analysis with variable time steps. With improvement over the previous work by Parvataneni et al. [1999], the time pattern information is added to the inputs and a simpler architecture is developed through more explicit utilization of the physical laws. A second order training algorithm with dynamic derivatives is also used to improve the training efficiency and accuracy. With these new features, this model can significantly outperform the previous approach in terms of accuracy and efficiency. The network is trained and tested using experimental data as well as analytical results. It is shown that this new model can compensate for time step variations and can predict the clutch torque accurately for a wide range of operating conditions.
Regulating Filling Pattern for Optimum Design of Resin Transfer Molding
Authors: Chen Y. F. , Minaie B. , Mescher A. M. 
Published: November 2021

Abstract
During resin transfer molding (RTM), dry spot formation and air entrapment during the filling stage often lead to inferior parts and high scrap rate. These problems are usually caused by improper design of inlet conditions and vent locations that prevent the Last Point to Fill (LPF) location from coinciding with the preset vent location. This paper presents a methodology to design the RTM process with a desired filling pattern free of dry spots. Unlike the traditional filling simulation that predicts the filling pattern using prescribed inlet conditions and the specification of the preform permeability field, this methodology calculates the optimum inlet conditions based on the specification of the desired filling pattern and the prescription of preform permeability. The use of this algorithm greatly enhances the process design capability by reducing trial-and-error procedures that use traditional direct filling simulation as a primary process design tool. The numerical algorithm is described along with RTM design example showing that use of the proposed methodology results in the LPF location coinciding with the preset vent location.
A Computational Study of Enhanced Heat Transfer in Laminar Flows of Non-Newtonian Fluids in Corrugated-Plate Channels
Authors: Metwally Hossam M. , Manglik Raj M. 
Published: November 2021

Abstract
The enhanced heat transfer behavior of laminar shear-thinning, power-law fluid flows in sinusoidal corrugated-plate channels is investigated. With duct plates at uniform wall temperature, periodically developed flows are considered for a wide range of channel corrugation aspect ratio (0 ≤ γ ≤ 1), flow rates (10 ≤ Reg ≤ 1500), and pseudo-plastic flow behavior indices (n = 0.5, 0.8, and 1.0). Typical velocity and temperature distributions, along with extended results for isothermal friction factor f and Collburn factor j are presented. The enhanced forced convection is found to be strongly influenced by γ, and the flow field displays two distinct regimes: undisturbed laminar or no swirl, and swirl flow regimes. In the no-swirl regime, behavior similar to that in fully developed straight duct flows with no cross-stream disturbance is obtained. The shear-thinning nature of the fluid, however, decreases f and enhances j. In the swirl regime, flow separation and reattachment in the corrugation troughs generates transverse vortices that grow with Reg and γ. The transition to this regime is also seen to depend on Reg, γ, and n, and in shear-thinning flows, it occurs at a lower Reg. The combined effects of corrugated plate geometry and non-Newtonian fluid rheology produce a heat transfer enhancement, as measured by the factor j/f, of over 3.3 times that in a flat-plate channel depending upon γ, n, and Reg.
Natural Convection From Horizontal Helicoidal Pipes
Authors: Al-Ahmadi Hamed , Fakheri Ahmad 
Published: November 2021

Abstract
Natural convection heat transfer from a horizontal helicoidal pipe is experimentally investigated for different coil-pitches. A modified characteristic length incorporating the tube diameter, the coil diameter, and the coil spacing, is proposed as the relevant scale for defining Nusselt and Rayleigh numbers. Using the proposed characteristic length, it is shown that the Nusselt number for horizontal helicoidal pipes can be determined using the available Nusselt versus Rayleigh number correlation for straight horizontal cylinders with high degree of accuracy over the range of the experimental data.
Two-Stage Non-Regenerative Silica Gel-Water Adsorption Refrigeration Cycle
Authors: Saha B. B. , Alam K. C. A. , Akisawa A. , Kashiwagi T. , Ng K. C. , Chua H. T. 
Published: November 2021

Abstract
Over the past two decades there have been considerable efforts to use adsorption (solid/vapor) for cooling and heat pump applications, but intensified efforts were initiated only since the imposition of international restrictions on the production and use of CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons). Closed-type, conventional adsorption refrigeration and heat pump systems have an increasing market share in Japan. In this paper, a two-stage non-regenerative, silica gel-water adsorption chiller design is outlined. Experimental measurements are performed on a prototype of a 3.5 kW rated cooling capacity adsorption heat pump in order to determine its performance under different operating temperatures (hot, cooling and chilled water). The chiller performance is analyzed in terms of cooling capacity and coefficient of performance (COP). The main innovative feature in the two-stage adsorption chiller is the ability to utilize low-temperature waste heat (∼55°C) as the driving source with a cooling source of 30°C. The technological difficulty inherent in operating a thermally activated cycle with such a small regenerating temperature lift (temperature difference between heat source and heat sink inlets) is overcome by use of a two-stage cycle.
Design, Analysis and Fabrication of a Meso-Scale Centrifugal Compressor
Authors: Laveau A. , Kapat J. S. , Chow L. C. , Enikov E. , Sundaram K. B. 
Published: November 2021

Abstract
A gas or vapor compressor is one of the key components of many engineering systems, such as certain designs of vapor compression refrigeration systems, cryo-coolers, air handlers. For meso-scale systems with linear dimensions of a few centimeters, conventional designs do not work efficiently because of rather large relative tolerances, and hence these meso-scale systems require micro-fabricated components for efficient operation. This paper presents a meso-scale centrifugal compressor fabricated by photo-lithographic techniques.
A preliminary design based on 1-D flow analysis using air as the working fluid shows that a 50 mm diameter centrifugal compressor with a blade height of 200 μm gives a static pressure ratio of 1.12. In this design, the impeller has 10 full blades and 10 splitter blades. Each blade has the NACA profile 9510 with the maximum camber at 50% of the chord. These impeller blades have exit angles 35° with exit flow angles of 60°. A vaned diffuser having 20 equally spaced vanes with the same NACA profile is used to improve compressor efficiency. A 3-D compressible, viscous flow analysis has been done using a commercial finite volume software. The results of this analysis allowed the verification of the flow characteristics inside the meso-scale centrifugal compressor.
The compressor has been fabricated using micro-fabrication techniques. The rotor and the stator are made by etching a silicon wafer by using DRIE (Deep Reactive Ion Etching) technique. A Pyrex wafer is then bonded to the stator for visual access inside the compressor.
A Review of Refrigerant Condensation in Horizontal Micro-Fin Tubes
Authors: Liebenberg Leon , Bergles Arthur E. , Meyer Josua P. 
Published: November 2021

Abstract
This paper reviews currently available experimental evidence and predictive techniques for heat transfer and pressure drop during film condensation in horizontal micro-fin tubes, as used in heat pump systems. The enhanced heat transfer mechanism of condensation using micro-fin tubes is explained, and special attention is paid to the dependence of heat transfer and pressure drop on the geometric parameters of the micro-fin tube. It is shown that most of the existing predictive heat transfer and pressure drop models employ strictly empirical techniques. The difficulty of accurate (analytic) modeling of micro-fin tubes lies in the numerous dimensional variables involved in the tube surface, and these are also reported. Heat transfer and pressure drop correlations for micro-fin tubes are presented for pure single fluids and pure mixtures (i.e. R-12, R-125, R-22, R-134a, R-113, R-407C, R-410A, R-32/R-134a, and R-22/R-502/R-134a). The saturation temperatures vary between 22 to 53°C, the mass fluxes between 84 to 910 kg/(m2s), tube diameters between 5.95 to 14.18mm, the number of fins from 24 to 65, fin heights between 0.1 to 0.25mm, apex angles from 25 to 90°, and helix (spiral) angles from 7 to 30°. Correction techniques are suggested when using refrigerant mixtures. It is shown that the currently available correlations satisfy only limited experimental data for a limited number of refrigerants, and that there is little unanimity over a single correlation. The appraisal of the existing correlations by numerous researchers is presented, and recommendations for design calculations are made.
An Experimental Study on Heat and Mass Transfer in a Helical Absorber Using LiBr+LiI+LiNO3+LiCl Solution
Authors: Yoon Jung-In , Moon Choon-Geun , Kwon Oh-Kyung , Kim Eunpil 
Published: November 2021

Abstract
An experimental study has been performed to investigate the heat and mass transfer performance in a falling film absorber of a domestic small-sized absorption chiller/heater. The components of the chiller/heater were concentrically arranged in a cylindrical form with low temperature generator, an absorber and an evaporator from the center. The arrangement of such a helical-type heat exchanger allows to make the system more compact as compared to a conventional one. As a working fluid, the LiBr+LiI+LiNO3+LiCl solution is used to get improved heat transfer. The heat and mass flux performance of the LiBr+LiI+LiNO3+LiCl solution shows 2 ∼ 5% increase than that of the LiBr solution. When a surfactant in the LiBr+LiI+LiNO3+LiCl solution is used, the performance of heat and mass transfer improves 15 ∼ 20%. This result shows the LiBr+LiI+LiNO3+LiCl solution with a surfactant can be applied to a small-sized absorption chiller/heater.
The Use of Decomposition for the Large Scale Synthesis/Design Optimization of Highly Coupled, Highly Dynamic Energy Systems: Part I—Theory
Authors: Muñoz Jules R. , von Spakovsky Michael R. 
Published: November 2021

Abstract
A general methodology for the decomposed optimization of highly coupled, highly dynamic energy systems is presented. The approach is based on the physical division of the system into units (sub-systems, components or disciplines) subject to functions describing the energy, cost and other couplings between them. Two versions of the approach are proposed. The first approach is called the Local-Global Optimization (LGO) Approach. LGO requires unit optimizations to be carried out with respect to purely local decision variables for various combinations of the functions that connect the units. The results are used to create an Optimum Response Surface (ORS) for the entire problem. The ORS is then searched by a system-level optimizer to find the values of the coupling functions that lead to an optimum system-level solution. The second approach proposed is an iterative version of LGO (ILGO). In this case, the ORS is closely approximated using a linear Taylor series expansion. The partial derivatives resulting from such an approximation are seen to correspond to the marginal costs typically used in the thermoeconomic literature. ILGO effectively and significantly reduces the number of unit optimizations required. The properties used to describe the coupling functions play a critical role in the convergence of ILGO to a global system-level optimum. A discussion of this and its implication for the choice of First or Second-Law based quantities for the optimization of systems is given.