bluuebunny/crossref_metadata_2025_split huggingface dataset:
Energy Efficiency Condition-Based Maintenance Methodology for Computer Room Air Conditioners
Authors: Fajardo Juan , Ramírez-León Hermes , Barreto Deibys , Rico Carlos , Cardona Camilo 
Published: February 2023

Abstract
A Computer Room Air Conditioner (CRAC) system has been modeled and simulated to set up a Condition-based maintenance strategy oriented on the equipment’s energy efficiency performance (MCEE). The modeling was performed using ASPEN HYSYS based on actual performance conditions of a CRAC system in the Caribbean Colombia area. The condition-based was simulated based on a fouling model increase in the evaporator and condenser, decreasing the heat transfer process and increasing the heat loss. A 2-year fouling increase model was performed to obtain an economic-technical cost-function parameter and develop a cost-effective cleaning schedule for the evaporator and condenser. The results show a 5% COP decrease due to a fouling increase. The maintenance schedule for cleaning this system is cost-effective on the 310th day. Furthermore, a Critical Matrix of the CRAC performance is developed based on energy efficiency and a cost function.
Overview of the Base Model for the Parametric Sensitivity Studies Specific to Performance Assessments of U-Mo Fuel Plates
Authors: Ozaltun Hakan , Roh Hee Seok , Mohamed Walid 
Published: February 2023

Abstract
This paper provides an overview of the base model specifically developed to perform parametric sensitivity studies on the U-10Mo monolithic fuel system. U-Mo monolithic fuels are being considered for the conversion of test reactors into high-performance research reactors that operate using proliferation-resistant, low-enriched uranium (LEU) fuels. These plate-type fuels contain a high-density, low-enrichment fuel sandwiched between zirconium diffusion barriers and encapsulated in aluminum claddings. All U.S. high-performance research reactors have released the designs of their LEU monolithic fuel reactor cores. These designs include nearly 50 distinct fuel plate geometries with different operational parameters. Consequently, a single generic plate geometry representing all the extreme points in this design matrix is unrealistic. To evaluate the performance for various parameters, a set of sensitivity studies was performed. These studies considered various input parameters (i.e., geometric, operational, and material property-related). The results revealed valuable information about plate performance and the sensitivity of this performance to various modeling inputs. To establish a reference state for comparing these result, base model featuring representative irradiation conditions was developed. To capture in-reactor behavior accurately, incorporation of representative constitutive models capable of evolving properties with respect to temperature, irradiation time, and burnup was needed. The behavioral models considered burnup-dependent properties, swelling, creep, and degradation. This paper introduces the base model created for the parametric sensitivity studies. The detailed description of the procedure includes the model geometry, model discretization, thermo-mechanical coupling, material properties and behavioral models. This paper also provides selected results and assesses the performance of the base model.
Analysis on Mechanical Properties and Corrosion Behavior of Friction Stir Processing of Commercially Pure-Titanium
Authors: Velukkudi Santhanam Senthil Kumar , Jeyarajan Joshua Richard , Manivannan Sathish Kumar , Jayamanickam Joseph Beski , Kuppusamy Raman , Nambi Nitin 
Published: February 2023

Abstract
Friction Stir Processing has become the ideal way to refine the grains which increases the mechanical properties like formability, microhardness, yield strength and Tensile Strength, also increases the corrosion resistance, which emerged as the effective way for selective surface modification and also retaining the bulk properties. In this present work, Titanium grade 2 (Commercially Pure Titanium) is selected as the material of choice due to its superior corrosion resistance compared to other grades of titanium, high tensile strength and high hardness. Due to soft, excellent corrosion resistance and ductile properties Cp - Ti is used in automotive parts and airframe structure application. Friction stir processing is being used to improve mechanical properties such as tensile and microhardness, as well as corrosion properties. Friction stir processing (FSP) is used to fabricate the Titanium plate, by varying the process parameters such as Tool Rotation Speed (rpm), Traverse Speed (mm/min), and Number of Passes. The process parameters used in this experiment are Tool Rotational speed of 1000 rpm, 1200 rpm and 1400 rpm, Traverse speed of 30 mm/min, 45 mm/min, and 60 mm/min and single pass, double pass and triple pass. Taguchi’s L9 Orthogonal array is used to conduct the experiment, which considers three parameters at three separate levels. A tapered cylindrical pin of HSS (High Speed Steel) with Rockwell hardness of 65 HRC is designed and fabricated to provide material flow while simultaneously minimizing the tool wear.
The tensile test was carried out using Universal Testing Machine (UTM) as per ASTM E8 standard to determine the ultimate tensile strength and yield strength of FSPed CP – Ti (grade 2), microhardness test was carried out using Vickers Hardness with a diamond indenter and corrosion values are evaluated using Immersion corrosion testing method by weighing the before and after weights of the sample as per ASTM G31 – 72. Since Titanium Grade 2 offers very high corrosion resistance, the rate of corrosion is negligible when done in 24 hours. Thus, immersion corrosion test is done over 120 hours, so that corrosion rate can be measured efficiently. And also evaluate the torque induced in this process. Grey Relational Analysis (GRA) is performed on the multiple test results such that tensile strength, microhardness and corrosion resistances to find the optimum process parameters, by applying the test results as inputs. Analysis of variance (ANOVA) is the most efficient parametric method for analyzing friction stir processing data from experiments results.
Soft Artificial Muscle Actuators for Undersea Launch and Recovery Systems
Authors: Cavallaro Paul V. , Smith Michael P. , O’Donnell Jacob D. , Redington Allison , Warner Eric 
Published: February 2023

Abstract
The pursuit of increased autonomy for undersea and surface vehicles presents challenges for their launch, recovery, positioning and control (LRP&C). Traditional rigid handling and actuator systems are often volume constrained and can limit payloads capacities and operational effectiveness. The need to innovate high capacity and compact actuation technologies is intensified by increasing demands for rapid deployability and stowability, scalability, adaptability, temporary buoyancy and connectivity across the undersea and surface domains. On-demand inflatable and compactable soft actuators may provide unique solutions with robustness needed to operate in extreme underwater environments. This preliminary research investigated the mechanical behaviors, load and stroke capacities, end termination designs and limitations of artificial soft fabric muscles (ASFMs), also known as McKibben muscles, constructed of High Performance Fibers (HPF) for potential launch, recovery, positioning and control of undersea and surface vehicles and interface platforms. Computational mechanics and experimental tests were performed on air-inflated ASFMs constructed of braided fabrics to evaluate their quasi-static behaviors. Both glass and aramid braid materials were studied for a range of diameters and lengths. The computational models supported the fluid/structure interactions by using an Equation of State (EOS) that governed the thermomechanical behaviors of the internal air during volumetric expansion and axial contraction of the ASFMs.
Design of a Miniature HVAC System to Function As a Multipurpose Cooling Shirt
Authors: Gale Jess , Cesmeci Sevki 
Published: February 2023

Abstract
The purpose of this project was to design and optimize a portable miniature cooling system. The device functions as a cooling shirt, which is particularly useful in high-temperature environments where maintaining a healthy body temperature is a concern. The design cooling capacity of the system is 0.586 kW, where it provides a circulating cooling fluid temperature of 21.1 °C, with an ambient temperature of 35 °C using refrigerant R-134A for the prototype. The circulating cooling fluid consists of a loop that is pumped through a brazed plate heat exchanger on the evaporator side of the system. The prototype used water for initial testing. Examples of high-temperature environments include a tradesperson working in an attic during the summer (i.e., HVAC technician and electrician). The device is not limited to only high-temperature environments. It could be used in many other applications, such as health care or physical therapy settings. Certain spinal injuries can cause the human body to lose the ability to regulate its core temperature. This could result in a scenario of the body overheating during physical therapy sessions. This device could help regulate core body temperatures when overheating is a major risk. An additional application includes the possible treatment of sports-related concussions and other sports-related injuries. Targeting specific areas for cooling could potentially increase recovery time when compared to standard ice treatments. Another example application may include certain military aircraft. Pilots can experience periods of thermal discomfort during flight. A greenhouse effect happens in aircraft that contain large window areas such as the V-22 helicopter. The device could potentially be used to offset the higher heat loads experienced during flights. In conclusion, in this paper, a benchmark study, which included the design, fabrication, and testing of a working prototype by using the off-the-shelf components, was presented. The COP of the prototype was tested at different settings. The percent error between the theoretical and actual COP was calculated to be about 19%. The sources of error were discussed. The future studies will include simulations in commercially available software such as AxCYCLE to reduce the percent error between the design and actual working conditions as well as further downsizing of the device by using customized cycle components.
Design and Fabrication of an Atmospheric Water Generator Based on Vapor Compression Refrigeration Cycle
Authors: Alshahrani Saad 
Published: February 2023

Abstract
Water generation from the atmosphere is an environmentally friendly alternative and a sustainable process to extract pure and fresh water. An atmospheric water generator (AWG) is a device that uses dehumidification to generate potable water out of moisture present in the air. The moisture or humidity present in the air is cooled below the dew point temperature and as a result, water vapor is condensed into water droplets. The collected water droplets are filtered and re-mineralized to produce fresh and potable drinking water. Using these principles, we have designed and fabricated a prototype system for extracting clean drinking water from atmospheric air using a vapor compression refrigeration cycle. An AWG is fabricated by using a secondhand window air conditioning unit with a capacity 18000 Btu/h. The device consists of an air filter, compressor, condenser, throttling device, and cooling coils. In addition, the device utilizes the dehumidified cool air to cool the condenser and improves its effectiveness considerably. During two operating days, the system was able to collect 5800 mL. Initially it was employed for two days starting from 12 noon, on October 3, 2020 to 12 noon, October 5th 2020. After that, the AWG was employed for two more days, staring from 12:30 pm, October 5th 2020 to 12 noon, October 7th 2020. During this run, 4100 mL of water was collected. It was found that the quality of collected water from the AWG was on par with that of normal drinking water. The quality of the collected water was assessed by an Oakton PC 450 waterproof portable meter with a combination probe and calibration system. The instantaneous temperature and relative humidity values are represented on the psychrometric chart to understand the possibility of water generation and are shown in results and discussions. During the aforementioned trial between 12:30 pm, October 5th 2020 and 12 noon, October 7th 2020, temperature and relative humidity readings were recorded.
Finite Element Simulation and Micro-Grain Size Analysis of Sheet Metal Casing by Hot Power Spinning
Authors: Xia Yingxiang , Shu Xuedao , Ye Bohai , Zheng Jiabin , Liu Yanli 
Published: February 2023

Abstract
Spinning is a typical continuous local plastic forming and an advanced manufacturing technology to achieve less cutting machining of thin-walled rotary parts. As the external bearing component of aero-engine, the mainstream manufacturing method of sheet metal casing is hot power spinning. Its forming quality includes dimensional, shape accuracy and macroscopic defects. The refinement and uniformity of micro grain size are also important indicators. The FE finite element) model of tapered sheet metal casing with variable wall thickness in hot power spinning was established by DEFORM-3D. The average deflection angle deviation Δθ and standard deviation of wall thickness error Δt was used as the evaluation indexes of 13 simulation schemes. The effect of the mandrel speed, the roller feed ratio, the roller fillet radius and the initial temperature on the forming quality was analyzed. Through the spinning experiment of SXY1000 double-roller CNC spinning machine, the metallographic structure of different forming regions and the micro grain size under different temperatures and roller feed ratios are explored. The micro grain size of the formed part is more refined with the increase of the initial temperature. It decreases as the feed ratio increases, while the microscopic grain size uniformity decreases.
MATLAB Toolbox for Design and Motion Analysis of Compliant Mechanisms and Soft Robots
Authors: Contreras Esquen Andrea , Delgado Juan , Soo Lance , Saldivar Kevin , Schwenck Lucas , Amiri Moghadam Amir Ali , Tekes Ayse 
Published: February 2023

Abstract
Despite the advantages and superiorities of compliant mechanisms and soft robots over rigid mechanisms, optimizing the stiffness of flexible links and dynamic properties of complex and high mobility designs is increasingly challenging. Additionally, the largest challenge in the design and modeling of such systems is understanding the deformation of the two bodies when connected along with their interaction in complex cases such as large deflecting buckling beams, especially for people who are new in the area. There exist several methods and techniques for obtaining kinematic relations as pseudo rigid body modeling (PRBM), first and second kind of Elliptica theory, discrete beam element method for simple geometries of compliant mechanisms, and nonlinear dynamical modeling of soft robots assuming using constant curvature spatial curves, and also machine learning. To address this issue, we present the user-friendly and open-access MATLAB Toolbox for the design and motion analysis of compliant mechanisms and soft robots. The developed toolbox serves as a platform to visualize the deformation of compliant joints and compliant beams (Module 1), visualize the displacement of various compliant mechanisms (Module 2), design simple and complex compliant mechanisms using the hinges and beams, and design and motion analysis of soft robots (Module 3).
Nonlinear Vibration Analysis of High-Speed Rotating Pre-Twisted FGM Blades Considering Initial Large Deformations
Authors: Chen Yukun , Jin Guoyong , Ye Tiangui , Li Shanjun 
Published: February 2023

Abstract
Rotating pre-twisted blades made of functionally graded materials (FGMs) have broad application prospects in engineering owing to their superior properties. With a high-velocity rotational motion, the blades would exhibit large-amplitude deformations due to the severe centrifugal forces and their vibration behaviors might be affected. This paper presents a nonlinear vibration analysis of rotating pre-twisted FGM blades considering the large-amplitude deformations caused by centrifugal forces. Based on the Carrera unified formulation and 3-D nonlinear elasticity shell theory, a prior large deformation analysis of the FGM blades under centrifugal forces is performed considering the geometrical nonlinear characteristics. The nonlinear vibration analysis of the system about the equilibrium position is then performed taking into consideration the deformed configuration and rotational motion. A systematic comparison of the present results with the 3D FEM solutions is performed to verify the correctness of the present method in determining the large deformation and vibration characteristics of the high-speed rotating pre-twisted FGM blades. The comparative performances of the linear and nonlinear models are assessed in the vibration analysis of the pre-twisted FGM blades with different rotating speeds and material parameters.
Model Order Reduction of Scramjet Isolator Shock Dynamics During Unstart
Authors: Sullivan Jack , Gaitonde Datta 
Published: February 2023

Abstract
The unsteady shock dynamics occurring in a numerically simulated unstarting scramjet isolator are examined using a novel model order reduction technique. The key challenges associated with the non-stationary nature of the phenomenon are overcome by leveraging a combination of Empirical Mode Decomposition (EMD) followed by time dependent snapshot shifting. The EMD method serves two purposes: to identify the oscillation modes of the unstarting shock train and to subsequently use the calculated non-stationary residual function to invoke a translating frame of reference that is co-moving with the unstarting shock system. Each snapshot is then shifted into the determined reference frame and subsequently windowed in space, creating a smaller, subset of snapshots from the original database. The windowing is informed by the physics of pseudo-shocks, and has the benefits of ensuring that each new snapshot contains the entire unstarting shock train, while simultaneously preventing the effects of circular shifting that have plagued other model order reduction techniques based on shift operators. When applied to the unstart problem, the shifting and windowing technique presents a more statistically stationary view of the unstarting shock dynamics in the frame of reference of the moving shock train. Dynamically relevant modes associated with upstream and downstream propagating pressure waves at the peak shock oscillation frequency in the boundary layers and separation regions are further extracted from the shifted and windowed snapshots using the sparsity promoting Dynamic Mode Decomposition algorithm.
3D Printing Material Testing and Applications in Biomaterial Modeling for Pediatric Medical Trainers
Authors: Perry Sheridan , Huayamave Victor , Gonzalez Bryan , Nadeau Zachary , Rodriguez Rafael 
Published: February 2023

Abstract
Additive manufacturing technologies have become increasingly prevalent in recent years and, with their abundance, have opened many doors in the field of manufacturing and design. The field of medicine has always been in high demand for new manufacturing techniques to create medical prostheses, devices, and trainers. With this increased need, 3D printing has become the obvious solution, and with it, a major problem has arisen. The lack of material property data on 3D printing filament post extrusion leaves designers and engineers having to perform extraneous tests to create accurate models. This paper summarizes an analyses of a common 3D printing filament known as Thermoplastic Polyurethane (TPU). The analysis included tensile testing in accordance with ASTM D638-14 and preliminary FEA based on the material properties found. It was found that TPU is a material that behaves in a similar manner to an elastomer with a low ultimate stress (50% infill yields 23.92 MPa +1.38 −1.12) and relatively low moduli of elasticity (50% infill sample 23.13 MPa +0.91 −0.87). TPU’s material characteristics change in respect to its infill percentage. A preliminary FEA analysis was also performed with results that agree with the material testing. Overall, the results from the physical testing and the FEA analysis were in agreement and allows for the creation of a foundation to extend the FEA validation with complex geometric models modeled after organic biomedical components.
Multibody Representation on the Coupling Between Wave Generator and Flexspline in Strain Wave Gears
Authors: Raviola Andrea , Bertolino Antonio Carlo , De Martin Andrea , Guida Roberto , Mauro Stefano , Sorli Massimo 
Published: February 2023

Abstract
Strain wave gears are widely employed in aerospace and industrial applications due to their capability to obtain a high reduction ratio with low backlash through light and compact design. Since this component is mostly used in applications requiring repeatable and high precision movements, its health assessment is crucial in assuring the required performance and avoiding unexpected failures. A detailed model of the gear, able to replicate its behavior in both nominal and degraded operating conditions, would allow simulating the presence of faults and to study their effects on the behavior of the machine on which the faulty component is mounted. The present paper describes how the initial conditions of a high-fidelity gear model can be obtained by simulating the insertion of the wave generator inside the flexspline. To do this, each tooth has been modeled as a single body with its own dynamics, connected to the surrounding teeth by equivalent visco-elastic models. The final deformed configuration of the flexspline is not imposed a priori, as commonly done, but it is directly obtained by the contact with the wave generator outer race. The simulation outcomes have been then validated with experimental data from the literature.
Unsupervised Online Anomaly Detection of Metal Additive Manufacturing Processes via a Statistical Time-Frequency Domain Approach
Authors: Chen Alvin , Kopsaftopoulos Fotis , Mishra Sandipan 
Published: February 2023

Abstract
Fault detection techniques in metal additive manufacturing (AM) have explored a variety of monitoring methods to flag anomalies as they occur during the sintering process. Although many in-situ techniques are able to adeptly detect these abnormalities, several utilize machine learning black box methods that do not easily transfer to varying print geometries. An approach that is adaptable to a multitude of geometries holds an advantage in determining anomalies for more complex cross-sections and raster patterns. To address this lack of a geometry agnosticism, we propose a method that detects faults using the frequency content of the melt pool image response through an unsupervised approach. Scan line length and scan speed extracted from known geometry can be translated to associated frequencies via a spectrogram. We examine three specific geometries to determine detection performance on each by comparing the frequency content to the nominal response. A deviation from the expected performance will signify that an anomaly has occurred. We verify this approach is feasible for fault detection and is accurate in detecting anomalies that are hard to observe in the image time series. A feasible geometry agnostic method and the current interpretability will be discussed in this paper. The results reached in this paper strongly indicate that the approach is promising, has potential for improvement, and that a geometrically independent method is sensible. With further work, a generic algorithm applicable on any geometry will be achievable.