bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Drilling Thrust for Straight and Inclined Micro-Hole in Thermal Barrier Coated Inconel 718 Superalloy
Authors: Khadtare Avinash N. , Pawade Raju S. , Joshi Suhas S. 
Published: January 2022

Abstract
The aero engine turbine blades made of Inconel 718, have thermal barrier coatings (TBC) to sustain high temperature air stream and cooling holes to reduce severe heat load. The complex physical and chemical properties of metal and ceramic layers pose challenges in a drilling these holes. Therefore, researchers have used laser and electrical discharge machining processes, which are time-consuming, costly, and inflict surface damages in and around the holes. To overcome these drawbacks, conventional micro-holes drilling has been adopted in this work. Drilling thrust distribution over cutting edges of micro-drills while drilling straight and inclined holes, under different cutting conditions has been analysed. The input parameters include: spindle speed, drill feed, and workpiece inclination, each at two levels. Each experiment was performed on TBC IN 718 sheet using a 600 μm TiAlN coated carbide drill under a dry peck-drilling cycle and was repeated twice. The results show that maximum elemental thrust in each experiment was found to be at the chisel edge. It was found to be 50–60% of the total thrust and varied non-linearly along the drill cutting edges, for straight as well as an inclined hole drilling. The unequal radial thrust distribution was observed due to workpiece inclination in case of inclined hole drilling, whereas a straight hole drilling shows an equal radial thrust distribution on each cutting edge.
Scalable Fiber Dip Drawing Method Using Automated Tracks
Authors: Heinz Abigail , Jao Dave , Beachley Vincent 
Published: January 2022

Abstract
A novel fiber production system established using principles of the dip drawing process is outlined in this paper, known as track spinning (TS). This system can produce micro- and nanofibers from polymer solutions for use in a variety of applications including filtration and biomedical devices. The system features automated tracks operated by a programmable motion controller in combination with stepper motors to consistently produce nanofibers. Utilizing a lignin-based solution, nanofibers of approximately 700–800 nanometers diameter have been successfully achieved and replicated with this device. TS offers wider compatibility with various solutions, in addition to scalability to fit the needs of the application or product. The TS device could open the doors to wide scale, automated nanofiber production.
Experimental Investigation of the Manufacturing of Porous Solid Oxide Fuel Cells
Authors: Wilhelm Cole , Schaffer Evan , Welles Thomas , Ahn Jeongmin 
Published: January 2022

Abstract
Solid oxide fuel cells (SOFCs) are typically operated in a dual-chamber setup, where the fuel and oxidant flows are separated by the fuel cell. However, dual-chamber SOFCs (DCSOFCs) require sealant to keep the flows separate, meaning that rapid heating and cooling cycling could break the seal. The initial answer to this problem was a single-chamber SOFC (SC-SOFC). The SC-SOFC is simply a planar fuel cell mounted parallel to a mixed fuel and oxidant flow. This system operates through the catalytic reactions of the anode and cathode with the fuel and oxidant, respectively. The drawback of this design comes from the requirement of fuel rich flow. A fuel lean flow leads to the oxidation of the anode and failure of the cell. On the other end, a fuel rich flow will greatly decrease system efficiency as much fuel will pass the cell and be wasted, making SC-SOFCs a difficult technology to implement. This issue led to the development of a porous SOFC (PSOFC), as a variant on the SC-SOFC. The PSOFC incorporates a similar mixed flow but is mounted perpendicular to the flow with cathode upstream of anode, and a catalyst downstream of the anode with the goal of reforming exhaust into syngas for a zero-emission fuel cell. Pores through the entire cell allow the flow to reach the anode, from the cathode side of the cell. The zero-emission condition is realized with the use of hydrocarbon fuels in the mixed flow. Reactions of fuel and air in the cell result in products of CO2 and H2O, which are then reformed by the catalyst into syngas (H2 and CO). Exhaust reformation by the catalyst is possible due to the high operating temperature of SOFCs. Syngas from the cell may be used immediately for further electricity generation or stored for later use. Manufacturing of a PSOFC is carried out with additive manufacturing (3D printing). Techniques of manufacturing PSOFCs will be discussed. The catalyst layer has been omitted from cell production until electricity generation performance of the cell improves. PSOFCs tested thus far have produced under 100 mW/cm2 with an open circuit voltage (OCV) of 0.60 V. This performance is not enough to begin implementing PSOFCs in industry. However, it does set a solid base for future PSOFCs and shows that they are a viable source of power generation. With further improvement of manufacturing methods and implementation of a catalyst, PSOFCs will become an important tool in zero-emission power production.
Advanced Exergetic Analysis of Preheat Train of a Crude Oil Distillation Unit
Authors: Fajardo Juan , Negrette Camilo , Yabrudy Daniel , Cardona Camilo 
Published: January 2022

Abstract
In this investigation, the conventional and advanced exergy analysis is used to obtain information about the conditions of the heat exchangers belonging to a crude oil distillation unit, previously to future studies to establish the most cost-efficient moments for the execution of maintenance activities in the exchangers. Conventional, unavoidable, avoidable, endogenous, and exogenous exergy destruction is calculated and the combinations between these last four terms. Mexogenous analysis is applied to individualize the relationships between the exchangers of the network. The results put the total exergy destruction at over 61.6 MW, being 63% avoidable. Five heat exchangers are considered critical because they concentrate the highest rates of exergy destruction, corresponding to 39% of the total exergy destruction in the network, this categorization allows focusing the improvement works on heat exchangers that will produce a substantial increase in the efficiency of the preheat train. Additionally, to evaluate the performance in a better way, the effect of unavoidable exergy destruction on performance measurement of exchangers through the exergy efficiency is studied, indicating that in some cases removing the unavoidable part can increase the second law efficiency by more than fifteen percentage points.
Tunable Topological Wave Control in a Three-Dimensional Metastable Elastic Metamaterial
Authors: Dorin Patrick , Liu Xiang , Wang K. W. 
Published: January 2022

Abstract
The concepts of topological insulators in condensed matter physics have been harnessed in elastic metamaterials to obtain quasi-lossless and omnidirectional guiding of elastic waves. Initial studies concerning topological wave propagation in elastic metamaterials focused on localizing waves in 1D or 2D mechanical structures. More recent investigations involving topological metamaterials have uncovered methodologies to achieve unprecedented control of elastic waves in 3D structures. However, a 3D topological metamaterial that can be tuned online to expand functionalities and respond to external conditions has yet to be developed. To advance the state of the art, this research proposes a tunable 3D elastic metamaterial that enables the reconfiguration of a topological waveguide through the switching of metastable states. Through careful design of internal bistable elements in the metastable unit cell, a switching methodology is developed to obtain topologically distinct lattices and a full topological bandgap. Analysis of the dispersion relation for a supercell reveals the presence of a topological surface state at the interface of topologically distinct lattices. Full-scale finite element simulations illustrate topological wave propagation in a 3D structure with a path that can be tailored on-demand. The research outcomes presented in this paper could be beneficial to potential applications requiring programmable and robust energy transport in 3D mechanical structures and serve as an inspiration for further work in adaptive 3D topological metamaterials.
Navigation and Path Planning of an Autonomous Mobile Robot
Authors: Nandikolla Vidya K. , Morris Eden , Aquino John , Paris Thomas , Wheeler Kevin 
Published: January 2022

Abstract
Autonomously navigating robots are used in many applications including assistive robotics, military, space exploration, manufacturing, etc. Unmanned ground vehicles (UGV) are an example of autonomous systems falling under the category of navigation, where navigation is dominantly composed of automatic transport and movement in real world environments. Simultaneous Localization and Mapping (SLAM) provides the best approach to the problems faced in unknown environments. Visual based cameras, light detection and ranging (LiDAR) sensors, global positioning systems, and inertial measuring units (IMU) feed constant streams of data to the SLAM algorithm. These sensors allow the UGV to explore an unknown outdoor environment whilst traversing around obstacles. The objects focused are construction barrels, cones, ramps, flags, and white lanes. Utilizing open source ROS packages, the UGV navigation algorithm uses 2D LiDAR, IMU, GPS, and depth camera data to combine the sensor inputs for a reliable robotic system. This paper demonstrates a robotic system combining RGB depth camera, object detection, and conventional outdoor SLAM navigation in unknown environments. Once a ramp or flag is detected an alternative path is implemented that is different from the global GPS path. The UGV combines all these methods to reliably explore unknown environments without the need for teleoperation.
Closed Greenhouse Heating in an Arid Egyptian Winter Using Earth-Air Heat Exchangers
Authors: Hegazy Anwar , Subiantoro Alison , Norris Stuart 
Published: January 2022

Abstract
In cold climate regions, closed greenhouses with minimal ventilation minimize the energy requirement for heating compared to open-ventilated greenhouses. In this paper, a model of a closed greenhouse with Earth-Air Heat Exchanger (EAHE) heating is presented and simulations are performed using climate data of a representative day of the coldest month of the year (i.e. January) at the case study location, Hurghada, Egypt. A comparison is made between a closed greenhouse with and without EAHE heating. The simulations show that without heating the greenhouse interior temperature drops below the minimum temperature for cultivation (20°C) during the early and late hours of the day. Furthermore, at midday the temperature inside the greenhouse exceeded the maximum temperature for cultivation (30°C). The results showed that EAHE enabled the greenhouse interior to be maintained at a temperature suitable for plant cultivation, cooling during the day and warming at night. Further, the variability in relative humidity was reduced from 35% to 15%, simplifying the control of the humidity within the greenhouse. Additional simulations that cover the winter period (November to February), demonstrated that the EAHE is a viable sustainable method for temperature regulation without any requirement for additional heating.
Compressible-Gas Coolants in Electromagnetic Heat Exchangers: A Thin Domain Model
Authors: Mohekar Ajit A. , Tilley Burt S. , Yakovlev Vadim V. 
Published: January 2022

Abstract
An electromagnetic (EM) heat exchanger (HX) converting EM energy into heat or mechanical work acts as a receiver end in high power-beaming applications. One potential design of an EM HX consists of a porous ceramic material, which is heated by EM waves, and a compressible gas coolant that delivers energy from the porous media to the outlet. The ceramic materials of interest absorb energy from the EM waves better as temperature increases, that can lead to extremely rapid temperature rises known as thermal runaway. Modeling such an EM HX requires an understanding of the gas dynamics taking place at the pore-scale when coupled with the phenomenon of thermal runaway. To capture the pore-scale gas dynamics, we consider a 2D thin and long structure with a channel carrying a pressure-driven ideal gas flow in perfect thermal contact with a thin ceramic layer. We derive two thin-domain asymptotic models: with and without thermal diffusion along the flow direction, each of which is solved numerically. We find that when local onset of thermal runaway takes place in the ceramic, diffusion along the flow direction at the microscale cannot be ignored. Unlike models of EM HX found in the literature, this work includes thermal expansion done by the gas at the microscale. By looking at temperature profiles at the steady-state, we show that Joule-Thompson cooling of the gas occurs locally when work done by the gas dominates.
Relative Pose Estimation for Cooperative Vehicles and Tracking of Multiple Dynamic Objects
Authors: Ghorai Prasenjit , Eskandarian Azim , Nayak Anshul , Doerzaph Zachary 
Published: January 2022

Abstract
A cooperative perception (CP) between two vehicles to work correctly requires relative positions between two vehicles to be established through a robust and accurate estimation method. This study focuses on relative pose estimation between two vehicles for cooperative perception-based autonomous driving through indirect methods. The indirect method utilizes the positioning data sharing from the Inertial Navigation System (INS) of each vehicle. The relative pose estimation is highly effective in cooperative perception where uncertainties are often involved due to full or partial occlusions caused by dynamic or moving objects such as Vulnerable road users (VRUs) to avoid hazardous situations. The objective is to enhance each autonomous vehicle’s perception capability beyond its own field of view through cooperation with other surrounding vehicles. Hence, in this study, the relative pose estimation between two vehicles in a dynamic situation is presented for cooperative perception-based automated driving system (ADS). The study also presents the detection and tracking results of multiple dynamic objects such as bicyclists, pedestrians, and other vehicles from the scene to avoid accidents or collisions during uncertain or critical situations by sharing their perception information.
Reciprocating Flow for Enhancing Thermal Performance of Latent Thermal Energy Storage Systems
Authors: Singh Virk Akashdeep , Park Chanwoo , Mitsingas Constandinos , Kweon Chol-Bum 
Published: January 2022

Abstract
Efforts related to the enhancement of thermal efficiency of latent thermal energy storage systems (LTESS) are primarily focused on increasing the heat transfer from heat transfer fluid (HTF) at phase change material (PCM) boundaries and increasing the heat conduction inside the PCM. For enhancing heat transfer at PCM boundaries, comparatively less attention has been paid to the thermodynamic characteristics of HTF at the PCM boundary. The current study describes a simple method of increasing heat transfer rate from HTF to PCM in a shell and tube LTESS by increasing the uniformity of temperature at HTF-PCM boundary compared to conventional unidirectional flow methods through the use of a periodically reciprocating HTF flow. This results in the generation of higher temperature gradients across the HTF-PCM boundary which leads to higher heat transfer rates, lower average temperatures, lower maximum temperatures, and lower temperature differences across the PCM. Detailed parametric studies are performed to investigate the effects of flow and heat transfer parameters of HTF, and the design of PCM container on the relative thermal efficiency of the latent thermal energy storage system with reciprocating flow to unidirectional flow.
Irreversibility Analysis, Design, and Optimization of a Combined Hybrid Hot Air and Buoyant Gas Balloon for Stratospheric Persistence
Authors: Trancossi Michele , Jose Pascoa 
Published: January 2022

Abstract
This paper presents the heat and mass transfer model and the design analysis of ALCHEMIST (Atmospheric Laboratory for the study of Circulation at High-altitude, Exchange of Markers and Intercontinental routes between Stratosphere and Troposphere). It is an innovative hybrid balloon project. It is constituted by coupling an external unconventional parachute envelope and a Hydrogen balloon. The dynamic equilibrium conditions with the surrounding atmosphere are considered. The system has been modeled as a limited unsteady irreversible thermodynamic living system. The mission is considered as an evolution of the system in equilibrium with the surrounding environment. Hence, a thermodynamic model based on irreversible thermodynamics is presented. The results according to both first and second law are produced and compared to actual flight data. The primary physical processes responsible for balloon performance aloft are accurately modeled in the proposed optimization process. The results demonstrate that the system could be optimized up to a stratospheric altitude around 30 km and shows that second law optimization produces an effective performance improvement.
Design of a Lightweight Robotic Mule
Authors: Su Jian , Zhi Xin , Lu Sha , Zhang Qichun , Dong Janet 
Published: January 2022

Abstract
Off road terrain poses a continual challenge to military movement. To meet this challenge, a robotic mule is designed to be a personal mobility device that can carry a soldier or that a soldier can carry. This paper will discuss the design process of such novel robotic mule, including overall structure, cargo/soldier platform, driving system, power system, and stress analysis and simulation. This robotic mule provides a new approach for army soldiers or soldiers’ equipment to move across field effortlessly and efficiently. The movement of the robot can be guided by GPS system or follow a soldier who carries emitter with sensor. The robot is designed to operate in nature terrain, which is standard nature trail in a boreal forest and may have a few roots and rocks but free from climbing obstacles.
The robotic mechanism is suitable for one-man lift, with weight not to exceed 20 kg. The robot is capable of moving through a standard door width 80 cm while fully loaded. The system can support 100 kg payload. It also provides soldier following capability and be able to perform with or without the operator on board. The system controls balance of the vehicle, while avoiding obstacles, and negotiating narrow urban or off-road terrain. The speed on flat terrain is 5–7 m/s with a range of 30 km.
The robot mule consists of a robust chassis platform, a driving system, a power system, a chair system for soldier, and GPS and vision system for autonomous control. For chassis platform, its structure is designed to be both light and sturdy. Stress analysis of the structure is applied to verify the safety of carrying objective payload. The width of the chassis platform is designed to access standard handicap door. For driving system, considering both terrain and weight limits, a four-wheel driving system is designed to overcome nature terrain which may have a few roots and rocks. Next, based on calculation of traction need and travel range, motor and lithium battery kit are selected to maintain target speed on flat terrain with target mileage. Power for extra functional features needed, such as sensors for navigation and surrounding detection etc. is also considered in calculation of battery capacity. Cargo/soldier platform is designed to provide proper space for carrying the soldier and/or equipment. Security fixtures are designed and added to the cargo/soldier platform which avoid swaying and falling of equipment. Also, ergonomics research is conducted to make a comfortable and hazards free platform for soldiers. Moreover, two handles are designed and will be mounted on each side of the robot mule, which makes the robot be lifted easily by a soldier and helps guard cargo payload in place.
Robotic System for Plant Tending in Remote Habitat
Authors: Hament Blake , Oh Paul , Carr Danielle , Moore Carl , Dev Satyanarayan , Ferguson Ian , Pena Pedro , Ehrlich Josh W. 
Published: January 2022

Abstract
The integration of robotics with agriculture in a controlled or closed environment is attractive because it enables remote production of food and oxygen without siphoning valuable hours of astronaut labor. Similar techniques can also be applied to terrestrial habitats to improve food security in areas that may not be well-suited to outdoor and/or labor-intensive traditional agricultural practices. In this paper, a robotic system for plant tending is presented with reflections on results of early demonstrations. The system includes remote teleoperation capabilities, a 6-DOF robotic arm, vision system for 3D reconstruction of plants, pneumatic multi-tool changer, and custom end-effectors including an enclosure latch tool and a plant shear tool. This work is a collaborative effort between NASA Kennedy Space Center, Lockheed Martin Space, and university partners to test the technologies of autonomous plant growth systems in deep space.
Numerical Investigation and Validation of Jet Temperature Effects on Nozzle-Afterbody Drag
Authors: Haznedaroglu Berke , Ciftci Omer , Cadirci Sertac , Aytac Serhad 
Published: January 2022

Abstract
In this study, jet temperature effects on afterbody drag in subsonic, transonic and supersonic flow conditions have been investigated for a wide range of nozzle throat total pressure to free-stream static pressure ratio (NPR) at Mach numbers 0.6, 0.9 and 1.2 using CFD. Preliminary CFD simulations are conducted for cold air flow with constant specific heat. Experimental data available in NASA Technical Paper 1766 is utilized for validation purposes thus, the CFD simulations are carried out for the identical geometry and boundary conditions reported in the technical paper. Depending on the Mach number, either pressure-based solver with coupled algebraic multigrid scheme or implicit density-based flow solver with Roe-FDS are used for the simulation of compressible flows to maintain convergence and obtain accurate solutions. Second order upwind schemes are preferred for all simulations and it is shown that convergence problems could be prevented when density based solvers are used at relatively high Mach numbers. For all simulations SST k-ω turbulence model proposed by Menter is selected. Based on a robust and verified CFD approach for cold jet analysis, the average drag coefficients Cd at various NPR values between 1.5 and 7 have been successfully estimated at all Ma with relative errors ranging from 5 to 15 % compared to experimental data. Then, the same numerical approach is adopted to the hot jet analysis. Further comparisons to empirical relations revealed a satisfactory agreement only at Ma = 1.2, but no acceptable match at Ma = 0.6 and 0.9.