bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal Properties Measurement of Particulate Fouling Samples of Air-Cooled Heat Exchangers Using Laser Flash Method
Authors: Sharma Arjun , Islam M. D. , Hajri Ebrahim Al 
Published: September 2020

Abstract
Fouling is one of the major factors that drastically affects heat exchanger performance. Especially in Middle East where most of the heat exchangers are air cooled due to scarcity of water. As these heat exchangers are placed in a harsh climate, they are at high risk of low performance due to dusty/sticky particulate fouling. In order to identify possible active/passive methods to control or ideally eliminate particulate fouling, it is desirable to know exact thermophysical properties of such particulate fouling. This study presents thermophysical property characterization of selected fouling samples from eight different fin fan heat exchangers installed in an oil & gas facility in the Middle East. Laser flash Analysis (LFA) method is a well-known technique for measurement of the thermophysical properties: thermal diffusivity, specific heat and thermal conductivity of materials. A new technique was developed to prepare powder particulate fouling samples to make them as disc shaped samples while maintaining the range of ± 12 mm diameter and ± 2 mm thickness. The LFA measurements was conducted using LFA 447 Nano Flash Netzsch over the temperature range from 25 °C to 125°C. The thermal diffusivity was measured with an accuracy of ± 3% and the specific heat capacity with an accuracy of ± 5%. As the thermal conductivity is a product of these two measured values, is calculated with an accuracy of ± 5.8% and the measurement repeatability was within 2%.
Comparison of Sweeping Gas and Direct Contact Membrane Distillation: Module Length Effect
Authors: Alqsair Umar F. , Alshwairekh Ahmed M. , Alwatban Anas M. , Krysko Robert , Oztekin Alparslan 
Published: September 2020

Abstract
Computational fluid dynamics simulations are conducted to compare the effect of module length in sweeping gas and direct contact membrane distillation systems for seawater desalination processes. In this work, the effect of temperature and concentration on the flux performance and temperature and concentration polarization characteristics are studied. CFD simulations are conducted in a three-dimensional module to characterize the steady-state velocity, temperature, and concentration field in the feed and permeate channel. The Reynolds number for the feed and the permeate stream is set to 500 and 1500, and thus the laminar flow model is adapted for each channel. The membrane properties are fixed in all cases considered. It is revealed that the local variation of the vapor flux, TPC, and CPC varies with module length in SGMD systems. However, the average values along the membrane in both module lengths do not vary much. Remedies for mitigating temperature polarization should be considered for future studies.
Study on Design Optimization of Fire Smoke Control Modes for Subway Transfer Channel With Ceiling Beams
Authors: Tian Xiangliang , Liu Chang , Zhong Maohua 
Published: September 2020

Abstract
In order to study the optimization modes of smoke control in the case of fire in metro transfer channel, a full-scale numerical station model with a single transfer channel is established. In case of fire, the influencing of ceiling beam, vent size on smoke control effect are analyzed. The ceiling temperature profile, CO concentration, visibility and smoke layer height under different conditions were studied to evaluate the smoke control effect of transfer channel and station hall. Based on this, the optimization suggestions of ventilation and smoke exhaust system design and smoke control modes for transfer channel are put forward. The results show that, the ceiling beams can effectively delay the speed of smoke diffusion and gain time for personnel escape and emergency rescue. The vent size has a great influence on the ventilation and smoke exhaust effect under the condition of meeting the designed ventilation capacity. Among the three common vent sizes listed in this research, the smaller the size is, the better the smoke control effect is. The length and width of vent with best smoke control effect are 1.2 m and 0.8m respectively.
Performance Improvement of Mass Transfer Through Membrane Using Ultrasound for HVAC Application
Authors: Gurubalan A. , Geoghegan Patrick J. , Maiya M. P. , Simonson Carey J. 
Published: September 2020

Abstract
Liquid desiccant dehumidification is one of the energy-efficient alternatives to conventional air conditioning systems for humidity control. Membrane dehumidifier is preferred to avoid the desiccant carryover, which occurs in a conventional packed bed dehumidifier. However, its mass transfer performance is lesser than that of the packed bed dehumidifier. This is due to additional mass transfer resistance of the membrane between the air and desiccant. It is found that the resistance by the boundary layer formed at the membrane-air interface accounts for a significant portion of the overall mass transfer resistance. Breaking of such boundary layer using ultrasound is an attractive technique to reduce the resistance. The present study experimentally investigates the influence of ultrasound on the mass transfer performance of a membrane humidifier. Subsequently, with the experimental results of the humidifier, the effect of ultrasound on the performance of the membrane dehumidifier is numerically studied. The performances of humidifier and dehumidifier are presented in terms of moisture addition or removal rate and latent effectiveness. It is found that the vibration due to ultrasound enhances the performance of the membrane dehumidifier by 1.5 times.
Analytical Model of the Soil Temperature Distribution Based on Weather Data
Authors: Reda M. Naser , Spinnler Markus , Mahamud Rajib , Sattelmayer Thomas 
Published: September 2020

Abstract
The measurement of soil temperature profiles for different locations or climates is essential for calculating the thermal performance of applications connected with the soil, e.g., underground heat storage systems. Estimating soil temperature profiles is identified as crucial knowledge for plant and crop growth as well as for germination in all agricultural tasks. The ground temperature depends on weather conditions (ambient temperature, solar irradiation, wind velocity, sky radiation, etc.) that contribute to the resulting temperature distribution within the soil close to the surface. In literature, several approaches have been discussed to predict soil temperature in different climates and locations, such as data-driven models, wavelet transform artificial neural networks, statistical models, etc. However, these models require extensive data sets from literature and high computational efforts. In the present study, a one-dimensional analytical model will be presented, which is based on the Green’s Function (GF) method. The model can estimate the daily and annual variation of the soil temperature distribution at different depths from real-time weather data sets. The model was experimentally validated with an accuracy of more than 96%. The significant advantage of the presented analytical method is the low computational cost, which is lower than that of numerical models by approximately two orders of magnitude.
Study of Hybrid Wet/Dry Cooling With Different Surface Morphology: Analyses on Pressure Drop and Thermal Performances
Authors: Saha Sudipta , Khan Jamil , Farouk Tanvir 
Published: September 2020

Abstract
This work conducts a multiphase multi-physics numerical study on this mixed mode cooling system, where evaporation of a liquid water film augments the convective cooling by evaporative heat and mass transfer. The mathematical framework consists of coupled mass, momentum, energy equation with species transport of air and evaporated water in the gas phase. Author’s prior works on perfectly flat surface predicted a minimum 500% increase of heat transfer coefficient in presence of a dual mode heat transfer. Current effort conducts a parametric study based on the different surface roughness structures over a broad range of Reynolds number condition. Array of circular, squared and triangular shaped grooves have been introduced along the surface exposed to the evaporating liquid. The cooling performances have been analyzed for different surface roughness structures and then compared against the flat film configuration. Furthermore, pressure drop across the liquid-gas interface has also been analyzed to predict the pumping power of the system. Model predicts that triangular shaped grooves exhibits a maximum ∼22% decrease in thermal resistance with a minimum pressure drop (∼5.5 times) across the interface. The square shaped surface morphology achieves 18% reduction in thermal resistance, with a penalty of pressure drop increase by a factor of ∼8. In comparison, circular grooves exhibit similar thermal performance but with a slightly a lower pressure drop (∼7 times). The numerical predictions have been compared with similar experimental findings and qualitative agreement was observed.
Thermal and Electrical Conductance of Pressure Tube/Calandria Tube Interface
Authors: Azih Chukwudi , MacCoy Reilly , Mazhar Hazem , Fraser Chris 
Published: September 2020

Abstract
In some engineered systems, the interface thermal conductance is a key parameter that governs the heat transfer behaviour of components in solid-solid contact. For example, in certain postulated accident scenarios for CANDU reactors, the pressure tube (PT) may deform into contact with the calandria tube (CT) to form a more direct path for heat transfer from the fuel to the moderator. There have been no direct measurements of interface thermal conductance in integrated “Contact boiling” experiments designed to mimic this Loss-of-coolant accident (LOCA) scenario due to the geometrical limits of the test components and the cumbersome nature of the instrumentation required to extract contact conductance data. It has been noted that the modelling of the contact conductance is one of the main sources of uncertainty in predicting the outcome of the contact boiling experiments that mimic LOCA scenarios. The present study demonstrated an analogy between the electrical and thermal contact conductance for PT/CT interfaces. The range of interface pressure and interface temperatures studies are selected to match the expected range of conditions during a CANDU LOCA scenario. The experiment setup consists of two sets of specimen representing PT and CT material. The specimen are instrumented with four K-type thermocouples in sequence to capture the temperature gradient imposed via a three-chamber oven. Within a range of interface pressures from 2 to 7 MPa and a temperature range from 510 to 720°C, the analogy is independent of the interface pressure or the load applied. This demonstrates the measurement of the electrical conductance between the PT and CT in contact boiling as a promising technique for obtaining in-situ information on the thermal contact conductance during integrated experiments.
Exploration of ZnO Nanostructure Growth on Various Metal Substrates for Enhancement of Surface Wettability and Evaporation Processes
Authors: Cabrera Samuel , Carey Van P. 
Published: September 2020

Abstract
Recent studies have indicated that ZnO superhydrophilic surfaces on copper and aluminum substrates enhance surface wettability and evaporation processes in droplet evaporation and pool boiling experiments. At slightly superheated surface temperatures, droplet evaporation on a nanoporous superhydrophilic surface exhibits onset of nucleation and nucleate boiling effects found in pool boiling processes. This study explores water droplet evaporation and quenching experiments conducted on nanostructured surfaces of a 45° downward facing pyramid copper, aluminum, and 304 stainless steel substrate. The nanostructured surfaces were used to conduct adiabatic droplet deposition, droplet evaporation, and quenching experiments. Through the three experiments and through surface characterization, by means of scanning electron microscopy, the underlying heat transfer performance and mechanism of droplet evaporation and pool boiling on various host metal substrates can be understood. The six surfaces tested were the following: bare copper, aluminum, and 304 stainless steel surfaces; and ZnO nanostructured surfaces on copper, aluminum, and 304 stainless steel. The experimental variables in this study were temperature and time. Through temperature and time measurements, the mean heat flux at varying superheats could be determined. Experimental results indicate the ZnO nanostructure enhances wettability and water evaporation on a variety of metal substrates. The presence of the ZnO nanostructure increases the mean heat flux and critical heat flux (CHF) in comparison to the bare metal surfaces. These results provide insight into the potential of enhancing spray cooling systems by growing a ZnO nanostructure on a heat exchanger fabricated of various metals.
Numerical Investigation of the Capture Efficiency of a Domestic Range Hood
Authors: Benchikh Le Hocine Alla Eddine , Poncet Sébastien , Fellouah Hachimi 
Published: September 2020

Abstract
Comfort criteria in building are increasing continuously. Multiple studies tend to use CFD approaches in order to predict and optimize the flow conditions accurately. One of the most relevant problematic is the extraction of the CO2 by kitchen hoods. In the present work, a new solver, based on a buoyancy Boussinesq solver and a turbulent passive scalar transport equation, is developed in OpenFoam to model the heated CO2 extraction by a rotating fan using the Multiple reference frame (MRF) approach. The new solver is first validated successfully against experimental results of a heated cavity and CO2 diffusion. An improvement of 30% in the capture efficiency is reached by increasing the extraction flow rate of the fan from 100 to 300 cfm. An extraction efficiency of 100% is observed for flow rates above 330 cfm. The novelty of this study is to present a new open-source solver able to model the rotation of the whole fan, CO2 transport and heat exchange simultaneously in steady state.
On-Machine Diamond Tool Shaping to Realize Highly Efficient Ultraprecision Machining System
Authors: Xu Meng , Yokoyama Naoyo , Nakamoto Keiichi , Takeuchi Yoshimi 
Published: September 2020

Abstract
Tool wear is one of the critical issues which deteriorate machining accuracy in ultraprecision machining. However, tool setting errors caused by the change of worn tool during a machining operation should be carefully compensated by identifying the gaps between the ideal tool center point and the actual tool center point, which inevitably lead to low machining efficiency. Because of the long consumption time of actual tool center point detection, this study aims at achieving on-machine shaping of a diamond tool which is commonly used in ultraprecision machining. In the previous study, shaping conditions without tool chipping are investigated by using various shaping materials. Then, in order to create a flank face that is necessary to realize preferable cutting, a pin gauge made of cemented carbide is adopted as the shaper. From the conducted experiments, it is found that the proposed on-machine shaping can create a specific cutting edge and a flank face on an ultraprecision machine tool.
A Conflict-Free Routing Method for Automated Guided Vehicles Using Reinforcement Learning
Authors: Chujo Taichi , Nishida Kosei , Nishi Tatsushi 
Published: September 2020

Abstract
In a modern large-scale fabrication, hundreds of vehicles are used for transportation. Since traffic conditions are changing rapidly, the routing of automated guided vehicles (AGV) needs to be changed according to the change in traffic conditions. We propose a conflict-free routing method for AGVs using reinforcement learning in dynamic transportation. An advantage of the proposed method is that a change in the state can be obtained as an evaluation function. Therefore, the action can be selected according to the states. A deadlock avoidance method in bidirectional transport systems is developed using reinforcement learning. The effectiveness of the proposed method is demonstrated by comparing the performance with the conventional Q learning algorithm from computational results.
An Automated Image Analysis and Cell Identification System Using Machine Learning Methods
Authors: Itano Keiko , Ochiai Koji , Takahashi Koichi , Matsushima Takahide , Asahara Hiroshi 
Published: September 2020

Abstract
In many biological laboratories, biologists analyze images and identify cell or organ states manually. There are some problems: lack of human resource and high experimental costs, among others. Identification results vary according to the person. To solve these problems, the process automation of biologists’ operations and quantitative identification are needed. Here, a cell-foci-phenotype identification system is developed by applying image processing and machine learning methods to fluorescent cell images. With this system, cell-foci-phenotype with high accuracy can be predicted and biologists’ efforts in doing image analysis can be reduced.
Fractional-Order Variable-Gain Super-Twisting Control With Application to Wafer Stages of Photolithography Systems
Authors: Kuang Zhian , Sun Liting , Gao Huijun , Tomizuka Masayoshi 
Published: September 2020

Abstract
In this paper, a novel fractional-order variable-gain super-twisting control (FVSTC) scheme is proposed and applied to improve the tracking performance of wafer stages in the photolithography systems. The FVSTC overcomes the drawbacks of the super-twisting control (STC) such as slow response speed and incomplete compensation to disturbances. First, to improve the dynamics of the states on the sliding surface, a fractional-order sliding surface is designed. Moreover, to improve the dynamics of the sliding mode variable, an equivalent-control-based method is utilized, and a switching controller based on a variable-gain super-twisting algorithm is deployed. Via such designed schemes, the proposed controller is robust against external disturbances and model uncertainties. Stability proof of the closed-loop system is provided. Numerical simulations to track a sinusoidal signal and experiments on a wafer stage testbed are conducted. The results show that the proposed FVSTC scheme can achieve much better tracking performance than conventional methods.
Strain Transfer Analysis for Surface Bonded Fiber Sensor Considering Temperature Influence
Authors: Hu Xiaochen , Fan Zhaoyan 
Published: September 2020

Abstract
Strain transfer ratio is one of the key characteristics to determine the accuracy of sensors for strain measurement and structural health monitoring. This paper presented a theoretical study on the strain transfer ratio of optical fiber sensors, which is generally bonded on the surface of target structure by adhesives to measure strain or stress. Compared to the prior efforts where only one type of loads, either mechanical or thermal, is considered, this paper included both of them in the modeling of strain transfer ratio and derived a general analytical expression for their relationships. It has been found that the strain transfer ratio is not a constant in some cases but varies with the strain being measured. The work studied the characteristics of fiber optic sensor in two consecutive approaches: 1) A simplified 2-dimentional multi-layer analytical model was built to derive the expression of strain transfer ratio as a function of the structural and material properties; 2) a numerical model that considers the realistic 3-dimentional structure of the sensor installation scenario was established for validating the analytical model in different case studies. Simulation results have shown that the analytical model matches well with the behavior of strain transfer ratio estimated by the numerical model, with an error less than 1.35%. Based on the validated analytical model, the discussion was further extended to derive the lower limit of the bonding length of optical fiber sensors to satisfy the requirement of measurement accuracy.
Active Interlayer Heating for Sustainable Selective Laser Sintering With Reclaimed Polyamide 12 Powders
Authors: Yang Feifei , Jiang Tianyu , Chen Xu , Lalier Greg , Bartolone John 
Published: September 2020

Abstract
Selective laser sintering (SLS) technology produces a substantial amount of un-sintered polyamide 12 powders after the manufacturing process. Failure to recycle and reuse these aged powders not only leads to economic losses but also is environmentally unfriendly. This is particularly problematic for powder particles close to the heat-affected zones that go through severe thermal degradations during the laser sintering processes. Limited procedures exist for systematically reusing such extremely aged powders. This work proposes a systematic method to maximize reusability of aged and extremely aged polyamide 12 powders. Building on a previously untapped interlayer heating, pre-processing, and a systematic mixing of powder materials, we show how reclaimed polyamide 12 powders can be consistently reprinted into functional samples, with mechanical properties even superior to current industrial norms. In particular, the proposed method can yield printed samples with 18.04% higher tensile strength and 55.29% larger elongation at break using as much as 30% of extremely aged powders compared to the benchmark sample.
Identification of a Kinematic Model of a 6DOF Industrial Manipulator With Angular Positioning Deviation “Error Map” of Rotary Axes
Authors: Alam Md Moktadir , Ibaraki Soichi , Fukuda Koki , Morita Sho , Usuki Hiroshi 
Published: September 2020

Abstract
To improve the overall “absolute” positioning accuracy for the industrial manipulator, it is indispensable to calibrate its kinematic parameters. In conventional studies, researchers have focused on Denavit–Hartenberg (D-H) parameters. However, until now, for industrial manipulators, the absolute accuracy is significantly poor than its repeatability. In this study, we propose a new kinematic model of a 6DOF (degrees of freedom) industrial manipulator with the angular positioning deviation “error map” of each rotary axis. The angular positioning deviation is modeled as a function of command angular positions, as well as the rotation direction to model the influence of backlash. We also propose a method to identify the angular positioning deviation of all the rotary axes by using a laser tracker.
A Real-Time Receding Horizon Sequence Planner for Disassembly in a Human-Robot Collaboration Setting
Authors: Lee Meng-Lun , Behdad Sara , Liang Xiao , Zheng Minghui 
Published: September 2020

Abstract
Product disassembly is a labor-intensive process and is far from being automated. Typically, disassembly is not robust enough to handle product varieties from different shapes, models, and physical uncertainties due to component imperfections, damage throughout component usage, or insufficient product information. To overcome these difficulties and to automate the disassembly procedure through human-robot collaboration without excessive computational cost, this paper proposes a real-time receding horizon sequence planner that distributes tasks between robot and human operator while taking real-time human motion into consideration. The sequence planner aims to address several issues in the disassembly line, such as varying orientations, safety constraints of human operators, uncertainty of human operation, and the computational cost of large number of disassembly tasks. The proposed disassembly sequence planner identifies both the positions and orientations of the to-be-disassembled items, as well as the locations of human operator, and obtains an optimal disassembly sequence that follows disassembly rules and safety constraints for human operation. Experimental tests have been conducted to validate the proposed planner: the robot can locate and disassemble the components following the optimal sequence, and consider explicitly human operator’s real-time motion, and collaborate with the human operator without violating safety constraints.