bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nine Degree-of-Freedom Kinematic Modeling of the Upper-Limb Complex for Constrained Workspace Evaluation
Authors: DeBoon Brayden , Foley Ryan C. A. , Nokleby Scott , La Delfa Nicholas J. , Rossa Carlos 
Published: September 2020

AbstractThe design of rehabilitation devices for patients experiencing musculoskeletal disorders (MSDs) requires a great deal of attention. This article aims to develop a comprehensive model of the upper-limb complex to guide the design of robotic rehabilitation devices that prioritize patient safety, while targeting effective rehabilitative treatment. A 9 degree-of-freedom kinematic model of the upper-limb complex is derived to assess the workspace of a constrained arm as an evaluation method of such devices. Through a novel differential inverse kinematic method accounting for constraints on all joints1820, the model determines the workspaces in which a patient is able to perform rehabilitative tasks and those regions where the patient needs assistance due to joint range limitations resulting from an MSD. Constraints are imposed on each joint by mapping the joint angles to saturation functions, whose joint-space derivative near the physical limitation angles approaches zero. The model Jacobian is reevaluated based on the nonlinearly mapped joint angles, providing a means of compensating for redundancy while guaranteeing feasible inverse kinematic solutions. The method is validated in three scenarios with different constraints on the elbow and palm orientations. By measuring the lengths of arm segments and the range of motion for each joint, the total workspace of a patient experiencing an upper-limb MSD can be compared to a preinjured state. This method determines the locations in which a rehabilitation device must provide assistance to facilitate movement within reachable space that is limited by any joint restrictions resulting from MSDs.
Assessment of Models for Extracting Thermal Conductivity From Frequency Domain Thermoreflectance Experiments
Authors: Saurav Siddharth , Mazumder Sandip 
Published: September 2020

Abstract
The Fourier heat conduction and the hyperbolic heat conduction equations were solved numerically to simulate a frequency-domain thermoreflectance (FDTR) experimental setup. Numerical solutions enable use of realistic boundary conditions, such as convective cooling from the various surfaces of the substrate and transducer. The equations were solved in time domain and the phase lag between the temperature at the center of the transducer and the modulated pump laser signal were computed for a modulation frequency range of 200 kHz to 200 MHz. It was found that the numerical predictions fit the experimentally measured phase lag better than analytical frequency-domain solutions of the Fourier heat equation based on Hankel transforms. The effects of boundary conditions were investigated and it was found that if the substrate (computational domain) is sufficiently large, the far-field boundary conditions have no effect on the computed phase lag. The interface conductance between the transducer and the substrate was also treated as a parameter, and was found to have some effect on the predicted thermal conductivity, but only in certain regimes. The hyperbolic heat conduction equation yielded identical results as the Fourier heat conduction equation for the particular case studied. The thermal conductivity value (best fit) for the silicon substrate considered in this study was found to be 108 W/m/K, which is slightly different from previously reported values for the same experimental data.
Temperature Dependence of the Contact Angle of Water on a Hydrophobic Surface at Pressurized Condition
Authors: Song Jia-Wen , Ma Meng-Chen , Fan Li-Wu 
Published: September 2020

Abstract
It is of both practical and scientific significance to study the temperature dependence of contact angles, towards development of surface wettability manipulation techniques for enhanced phase change heat transfer as well as the theoretical estimation of solid interfacial energy. However, the variations of surface wettability of a hydrophobic solid with altering temperature remain unclear. In this work, in situ characterizations of the contact angle of water on Teflon (PTFE) surfaces as well as the surface tension of water over a temperature spectrum from ∼25 °C to 160 °C at pressurized condition (2 MPa) were conducted by employing the sessile drop and pendant drop methods, respectively. A nearly invariant trend of the contact angle of water was observed over the entire temperature range. Moreover, it was shown that the surface tension of water linearly declines with raising the temperature. Based on the theory of surface thermodynamics, the effects of temperature on the contact angles were analyzed with the variations of interfacial tensions.
Enhanced Pool Boiling Heat Transfer During Quenching on Micro/Nanostructured Wicking Surface: Effects of Submicron-Scale Substructures
Authors: Zhang Jia-Yi , Li Jia-Qi , Fan Li-Wu 
Published: September 2020

Abstract
Micro/nanostructured wicking surfaces with different submicron-scale substructures were fabricated by using electrochemical deposition and chemical etching methods on stainless steel spheres. Quenching experiments were carried out on these surfaces in saturated water to reveal the effect of submicron-scale substructures on the boiling heat transfer enhanced by wickability. The results indicated that, as compared to the knife-like submicron-scale substructure, the needle-like substructure improved the wickability of wicking surface, but has a weaker boiling heat transfer enhancement. The difference in wicking/spreading performance between two wicking surfaces with different submicron-scale substructures could not be enough to significantly affect the boiling heat transfer during quenching. However, the knife-like substructure might have a larger specific surface area, resulting in a greater boiling heat transfer enhancement. Besides, liquid spreading distance measured at room temperature might not be suitable for the wickability characterization.
Enhanced Steam Condensation Heat Transfer on a Honeycomb-Like Microporous Superhydrophobic Surface Under Different Condensing Pressures
Authors: Zhang Tian-Yu , Mou Lin-Wei , Li Jia-Qi , Fan Li-Wu 
Published: September 2020

Abstract
Steam condensation heat transfer was studied over a honeycomb-like microporous superhydrophobic surface under various pressures, in order to elucidate the effects of pressure on the jumping-droplet condensation behaviors. The condensing pressure was varied from 4 kPa to 13 kPa, based on the typical operating conditions of condensers in power plants. Stable coalescence-induced droplet jumping was realized on the honeycomb-like superhydrophobic surface over this range of pressure, leading to a great enhancement on the condensation heat transfer as compared to that on the common hydrophobic surface, especially at small degrees of subcooling (e.g., &lt; 10 K). The frequency and number of jumping droplets were observed to decrease at lower pressures because of the less amount of condensate produced, and at higher degrees of subcooling due to the occurrence of surface flooding. The increasing condensing pressure was found to lead to a later onset of surface flooding. The results indicated that the honeycomb-like superhydrophobic surface has a great potential for industrial condensation equipment operating at multiple pressures owing to its superior performance and facile fabrication.
Thermal Analysis of Phase Change Material Based Heat Transfer Fluid in Solar Thermal Collector
Authors: O’Neil Tyler J. E. , Lim Celine S. L. , Sobhansarbandi Sarvenaz 
Published: September 2020

Abstract
Phase change materials (PCMs) are commonly used as energy storage mediums in solar thermal systems. This paper investigates the mixture of PCM doped with nanoparticles to be used as HTFs directly integrated in a U-pipe ETC to be applied in solar thermal collectors. The selected type of PCM-HTF in this study is erythritol (C4H10O4), with high specific heat capacity in liquid form, as well as its unique sub-cooling behavior. In order to overcome the low thermal conductivity of erythritol and further enhance specific heat capacity, a weight concentration of 1% multi-walled carbon nanotubes (MWCNT) is added. Additionally, to insure even distribution of MWCNT and consistent properties of the HTF, triethanolamine (TEA) is proposed to be incorporated as a dispersant. The samples were each tested in a Thermogravimetric Analyzer (TGA) and Differential Scanning Calorimeter (DSC) to analyze their thermal properties. The results from the DSC tests show 12.4% enhancement of specific heat capacity of the proposed HTF mixture as well as nearly 5° C depression of freezing onset temperature. This study allows for the optimization of the operating temperature range of the collector when integrated with these materials, where direct heat gain can be obtained in the collector.
The Effect of Turbulence Promoters on Vacuum Membrane Distillation Module Performance
Authors: Krysko Robert , Alasiri Abdulaziz M. , Alqsair Umar , Cosman Sertac , Oztekin Alparslan 
Published: September 2020

Abstract
Computational fluid dynamic simulations are conducted to compare the performance of three proposed VMD module designs. Key parameters, including concentration polarization coefficient (CPC), temperature polarization coefficient (TPC), mass flux, and module pressure drop, are evaluated to analyze flux performance and membrane wetting implications. The CFD simulations are conducted on a three-dimensional domain for each design with representative membrane properties. The Reynolds numbers evaluated are 500 and 1500. Contour plots are provided to gain insight into the flow-field characteristics. Stream-wise profiles and average values are provided as a means to compare the design performance. The results indicate that adding either net-type spacers or membrane corrugation to the feed channel provides performance enhancement over an empty channel design. It is found that both the net-type spacer concept and the corrugated membrane offer better flux performance over the baseline design (49%–60% for the net-type spacers and 62%–67% flux enhancement for the corrugated membrane), reduced concentration polarization coefficient (51% for the Re = 500 case and 45% for the Re = 1500 case for spacers and 58% for the Re = 500 case and 49% for the Re = 1500 case for corrugation), increased TPC (2%–3% higher), and increased wall shear stress over the baseline design. The most significant finding is that the corrugated membrane design accomplishes the listed performance improvement while yielding five times less pressure drop increase than the net-type spacer design.
Optimization of Mixed Hydrophilic and Hydrophobic Surfaces Under Laminar Flow Conditions
Authors: Frymyer Brian , Oztekin Alparslan 
Published: September 2020

Abstract
When condensation first forms on a surface, it starts as tiny droplets. As the surface continues to collect condensation, the droplets grow together and form a film. The film increases the thermal resistance of the system. It is possible to remove the fluid from the condensing surface before it develops into a film. Dropwise condensation has the capability of providing up to an order of magnitude higher heat transfer than film condensation.
A hydrophobic surface is capable of sustaining dropwise condensation but creates a high energy barrier that restricts nucleation. A hydrophilic surface has a low energy barrier for nucleation but retains the water quickly transitioning to film condensation. A hydrophilic and hydrophobic patterned surface creates a surface with a low nucleation energy barrier and is capable of sustaining dropwise condensation.
Surface patterns are evaluated under laminar flow conditions to maximize mass collection. The surfaces are evaluated using a thermal model, which includes an equivalent thermal resistance for diffusion. Laminar flow rates are evaluated using Reynolds numbers from 1,218 to 4 × 105. Hydrophilic nodules sizes are evaluated from 0.1 mm to 3.7 mm. Under natural convection flow, mass collection can be increased by 20% with respect to film heat transfer.
Effects of Material on the Heat Transfer of R410A During Condensation and Evaporation
Authors: Tang Weiyu , Zheng Boren , Li Wei 
Published: September 2020

Abstract
An Experimental investigation was conducted to demonstrate the effect of material on the heat transfer characteristics of R410A during evaporation inside two horizontal plain tubes with the same inner diameter of 6mm, and they are made of aluminum and stainless, respectively. The variation of vapor quality for test section were kept at 0.2–0.9, and mass velocities varied from 100 kg m−2s−1 to 400 kg m−2s−1. A series of single-phase and repetitive experiments was conducted to verify the accuracy and reliability of the test rig firstly. Various flow patterns including stratified, slug, and annular flow even dry-out may exist during the flow boiling experiments, while both ΔT-dependent and ΔT-independent flow are included for the test conditions of condensation. The results for evaporation have shown that the plain aluminum tube performs the best for all tested mass velocities. Several different correlations were employed to predict the present data and their predictive ability were compared. The results indicate that the Liu and Winterton can predict all the data points in an acceptable error band, and the slightly worse thermal performance of the stainless-steel tube may be attributed to the relatively low thermal conductivity. For condensation, little difference was found between two tested tubes, which means that the material and roughness may have little effect on the heat transfer performance during condensation.
Retracted: “A Numerical Study on the Shell-Side Thermal-Hydraulic Performance of a Hybrid Smooth and Spirally Corrugated Tube” [ASME 2020 Heat Transfer Summer Conference, Virtual, Online, July 13–15, 2020, Conference Sponsors: Heat Transfer Division, ISBN: 978-0-7918-8370-9, Copyright © 2020 by ASME. Paper No. HT2020-8996, pp. V001T09A010; 7 pages; doi: 10.1115/HT2020-8996]
Authors: ASME  
Published: September 2020

Abstract
This paper was removed from publication at the author’s request. October 2, 2020.
Copyright © 2020 by ASME
Experimental Study on Condensation in the Outer Annular Region Outside Horizontal Enhanced Tubes
Authors: Dong Zeguan , Zhang Jianghui , Li Zhen , He Yan , Kukulka David J. , Lei Wei 
Published: September 2020

Abstract
Single-phase and flow condensation experiments were performed using refrigerant R410A in the outer annular region of horizontal enhanced tube with different enhanced surfaces at a saturation temperature of 45°C in the range of mass flux 44.43–102.23kg/(m2s). The vapor quality ranges from 0.8 to 0.2. The outer diameters of the tubes are all 19.05mm, but the inner diameters are slightly different due to different surface structures. The surface structures of the three enhanced tubes are fins(EHT1 tube), toothed structures (EHT2 tube) and fine cavities(EHT3 tube) of different sizes and densities. Among them, the EHT3 tube has internal threads. Wilson diagram method was used to determine the enhancement ratio of the water side heat transfer coefficient of EHT3 tube. It was found that the pressure drop increased with the increase of mass flux, while the heat transfer coefficient showed different trends, and the smooth tube was always the lowest of the four tubes. A comprehensive evaluation factor α combining heat transfer enhancement factor (EF) and pressure drop penalty factor (PF) was defined, in which EHT2 tube (1.38–1.75) was the largest, with strong heat transfer capacity and small pressure drop, so the condensing heat transfer capacity of EHT2 tube was the best.
Comparison of Different Liquid Cooling Configurations for Effective Thermal Management of Li-Ion Pouch Cell for Automotive Applications
Authors: Bakhshi Shashwat , Dubey Prahit , Srouji A. K. , Wu Zenan 
Published: September 2020

Abstract
An effective cooling mechanism is the backbone of a good automotive battery thermal management system (BTMS). In addition to prevention of extreme events such as thermal runaway, an automotive BTMS must be able to efficiently tackle aggressive environmental temperatures, and/or discharge and charge conditions during electric vehicle operation. Moreover, electrical performance and cycle life of the battery modules and packs are closely tied to the battery temperatures and thermal gradients, which increase with increase in C-Rates. In order to keep the battery temperatures to be under the operational temperature limit, it is crucial that the selected cooling mechanism provides efficient transport of the heat generated by the battery modules and packs to the cooling media under all discharge and charge conditions. Owing to its efficient thermal performance, liquid cooling is preferred by most electric vehicle manufacturers for battery thermal management. This usually incorporates battery modules exchanging heat with a flowing coolant via cold plate or cooling channels during operation. The current work aims to investigate different liquid cooling configurations and compare their relative thermal performance during operation of a high energy density Pouch Cell. The four configurations selected for this comparison are (1) Face cooling, (2) Single-Sided cooling, (3) Double-Sided cooling, and (4) a Hybrid cooling configuration. Test setups comprising of a commercially available 9 A-h NMC Pouch cell, cold plates, pump, heat exchanger, refrigeration cooling unit, and thermal sensors are built for the above four cooling configurations. During the tests, the selected cell is discharged at different discharge rates (C-Rates), i.e., 3C, 4C, and 5C. The overall cell temperatures and thermal gradient across the cell are measured using T-type thermocouples for the four cooling configurations. In order to capture the thermal gradient across the Pouch cell accurately, several thermocouples on the face of the cell are installed using a thermal interface material. Results show the superiority of Face cooling configuration in terms of overall thermal performance under all considered test conditions. Lowest cell temperatures and thermal gradients across the cell are observed for the Face cooling configuration, while highest temperatures and thermal gradients are observed for the Single-Sided cooling configuration. Much improved thermal performance is also observed in the case of the Hybrid cooling configuration as compared to the Single and Double-Sided cooling configurations. As implementation of the Face cooling configuration at the battery pack level may result in higher weight and cost of the battery pack, owing to its good thermal performance and straightforward scaling to battery pack level, the proposed hybrid liquid cooling mechanism provides a viable alternative to Face cooling for battery thermal management.
3D Printed Architected Heat Sinks Cooling Performance in Free and Forced Convection Environments
Authors: Ali Mohamed I. Hassan , Al-Ketan Oraib , Khalil Mohamad , Baobaid Nada , Khan Kamran , Abu Al-Rub Rashid K. 
Published: September 2020

Abstract
In this work, we extend our heat transfer performance study on our proposed new and novel 3D printable architected heat sinks with geometrically complex structures based on triply periodic minimal surfaces (TPMS). Computational fluid dynamics (CFD) modeling is used to assess the effect of porosity distribution, heat load, and isothermal boundary condition on the performance of the proposed TPMS-based heat sinks in active cooling using natural and forced convection heat transfer environments. The convection heat transfer coefficient, surface temperature, pressure drop are predicted using CFD method. The CFD model is validated using experimental results for the pressure drop and is verified by standard analytical results. Three TPMS structures are investigated in different orientations. Dimensionless heat transfer groups are developed to globalize the heat transfer performance of the proposed heat sinks.
Molecular Dynamics Simulation of Ultra-Fast Phase Transition in Water Nanofilms
Authors: Porterfield Malcolm , Borca-Tasciuc Diana 
Published: September 2020

Abstract
Molecular dynamics simulations are used to explore explosive boiling of thin water films on a gold substrate. In particular, water films of 2.5, 1.6 and 0.7 nanometer thickness were examined. Three different surface wettabilities with contact angles of 11, 47 and 110 degrees were simulated along with substrate temperatures of 400K, 600K, 800K and 1000K. The 11 degree contact angle was obtained using a Morse interaction potential between the water film and the gold substrate while the 47 and 110 degree contact angles were obtained via a Lennard-Jones potential. Evaporation was the first mode of phase change observed in all cases and explosive boiling did not occur until the substrate reached a temperature of 800K. When explosive boiling was present for all three contact angles, it was consistently shown to occur first for the surface with a 47 degree contact angle, contrary to the expectation that it would occur first on the substrate with an 11 degree contact angle. These results suggest that explosive boiling onset is strongly dependent on the particularities of the interaction potential. For instance, the Morse potential used to model the surface described by an 11 degree contact angle, is a softer potential as compared with Lennard-Jones, but has more interaction sites per molecule — two hydrogen atoms and one oxygen atom vs one oxygen atom. Thus, although the water film reaches a higher temperature with the Morse potential, explosive boiling onset is delayed as more interaction sites have to be disrupted. These results suggest that both the interaction strength and the number of atoms interacting at the interface must be considered when investigating trends of explosive boiling with surface wettability.
Measuring Heat Transfer From Firebrands to Surfaces
Authors: Bearinger Elias , Lattimer Brian , Hodges Jonathan , Rippe Christian 
Published: September 2020

Abstract
Firebrands are an important mechanism of fire spread and one of the primary ways in which wildland fires ignite structures. Inverse heat transfer using thin steel plates has been shown to be an effective method for measuring heat transfer distributions from firebrands. To fully understand the dynamic process of heat transfer from firebrands to surfaces; however, it is necessary to view the underside of the firebrands, which is not possible through a steel plate.
This work develops a method of inverse heat transfer using a visually transparent quartz plate and a long-wave (7.5–14.0 μm) infrared camera to facilitate visual access to the firebrands from all angles. The heat flux measurements using a quartz plate were compared with heat flux measurements using a steel plate and finite element heat transfer simulations for radiation-dominant tests using heater panels. Additionally, heat transfer measurements using cuboidal oak firebrands were conducted using both the quartz and steel plates. A corrective factor was developed based on the ratio of the effective emissivity of the quartz and stainless-steel plates at typical firebrand temperatures. The measured heat fluxes were within 1–6% after correcting for radiant energy transmitted through the quartz which was absorbed by the stainless-steel plate.