bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparing Different Designs of a Grid-Valve for Industrial Steam Turbines
Authors: Bianchini Cosimo , Da Soghe Riccardo , Giannini Lorenzo , Maceli Nicola , Arcangeli Lorenzo , Mariotti Vanessa 
Published: September 2023

Abstract
The current energy market is characterized by the increasing split of energy produced with renewables, and by the strong push towards a sustainable use of the resources and a reduction of the global carbon footprint. Both these two aspects underline the importance of operating the energy production plants in an efficient and effective way not only at full but also at partial load.
This paper presents the results obtained using a CFD commercial code to understand how the different design choices affect the performance of a grid-valve used for steam turbines in the industrial power generation market. Several different configurations were considered, mainly to understand the best trade-off in terms of performance and mechanical aspects. In fact, the grid valves are intended to have a certain modularity and are designed to operate within a given range of conditions and applied to different steam turbine architectures. At best, they should be able to deliver the same performance regardless of the operating conditions or the steam turbine architecture. Therefore, part of the activity focused on the criteria to be used to decide the size the grid valve with respect to the mass flow and the downstream flowpath.
A significant part of the analytical efforts was also devoted to provide a set of rules to account for the performance variability. To this purpose, a significant number of cases was used to cover the most relevant factors affecting the performance of the grid valves. Considered factors include: the variability of the radial length of the stages downstream of the grid valve, the pressure ratio through the grid valve, and the amount of flow extracted upstream of the grid valve.
Experimental Study of Compressible Film Cooling Scaling and Hole Geometry
Authors: Fox Dale W. , Furgeson Michael , Flachs Elise M. , Bogard David G. 
Published: September 2023

Abstract
While modern gas turbine engines operate at hot gas path velocities approaching the speed of sound, few facilities have studied the effects that the flow’s compressibility can have on the adiabatic effectiveness. A new facility at the University of Texas at Austin has been developed to investigate these high Mach number effects and how to appropriately scale laboratory film cooling experiments to engine conditions. This study investigates two film cooling hole geometries, a baseline 7-7-7 shaped film cooling hole and a recent design which has been numerically optimized for increased effectiveness. Both holes are tested at mainstream Mach numbers of 0.25 and 0.50 in a flat plate test section. The optimized hole outperforms the effectiveness of the baseline geometry at all blowing ratios tested, matching the trend in the results of previous studies on these geometries. However, there is a marked decrease in film cooling hole performance as the Mach number is increased.
Comparison of Infrared Spectroscopic Methods in Predicting DCN of Jet Fuels and Their Blends Using Chemometric Tools
Authors: Dalmiya Anandvinod , Sheyyab Manaf , Mayhew Eric K. , Brezinsky Kenneth , Lynch Patrick T. 
Published: September 2023

Abstract
Fuels are made up of thousands of chemical components, but these can be grouped into far fewer chemical functional groups. Fuel properties can be correlated to simpler fuel representations, potentially as simple as the composition of their functional groups. Machine learning (ML) models have been built to predict fuel properties from spectroscopic measurements (preferably in liquid phase). Derived cetane number (DCN) is one such property, which is an indicator of ignition quality in compression-ignition engines. Attenuated total reflectance (ATR) spectroscopy has advantages over transmission-based approaches to overcome challenges associated with the narrow pathlength liquid cells (&lt; 10μm) needed to avoid saturation in strong absorption bands in the mid-infrared. In our previous work, we demonstrated the use of Fourier transform infrared (FTIR) spectra (through transmission) in predicting the DCN of jet fuels after eliminating saturated regions. Convolutional neural network (CNN) models performed the best with a mean percentage error of 3% with an R2 score of 0.931 over a spectral region that includes the fingerprint region. Although those models have shown high predictive capability, since they ignored information from regions likely to show saturated features, it is intuitive that prediction capabilities could be improved further with access to the information in these regions. To evaluate the impact of these saturation regions on DCN estimation, we compare the prediction accuracies and important regions corresponding to DCN obtained from models trained on FT-ATR spectra, which include the regions excluded in the previous work. In this work, uncorrected ATR spectral measurements were used in developing calibration models for predicting DCN of jet fuels and their blends. ATR spectra of jet fuels like F-24, an alcohol-to-jet fuel, Jet-A, etc., and neat hydrocarbons and their mixtures, which in their assembly, represent the chemical functional groups present in jet fuels, were collected using an analytical grade FTIR spectrometer. Spectral measurements between 4000–650cm−1 were used in this analysis, and important spectral regions associated to functional groups correlating to DCN were also identified.
A Strategy for the Design of ORC Multi-Stage Axial Turbines for Geothermal Energy Conversion
Authors: Manfredi Marco , Persico Giacomo , Dossena Vincenzo , Cosi Lorenzo , Forte Annalisa , Arcangeli Lorenzo 
Published: September 2023

Abstract
Geothermal energy is one of the most attractive renewable sources, largely available across US and Europe, but featuring medium-low enthalpy level. Such kind of energy source can be effectively exploited by resorting to Organic Rankine Cycles (ORCs), namely phase-change cycles based on organic fluids, whose thermo-physical properties better match with the low heat grade of the geothermal fluid. Nowadays, ORCs stand out as a mature energy conversion technology, whose performance and tecno-economic optimization greatly rely on the efficiency, reliability, and cost of the turbine. The use of organic compounds implies a peculiar aerodynamic design, where the low specific work and the low speed of sound often lead to turbines featuring one or a few transonic/supersonic stages. For this reason, ORC turbines were historically characterized by lower efficiency and rangeability with respect to steam turbines.
This work presents a strategy to design multi-stage axial turbines for ORC power systems devoted to geothermal energy conversion. Starting from a set of turbine operating conditions, several turbine flow paths are optimized at preliminary level, considering alternative configurations in terms of angular speed, number of stages, and size. A peculiar case study is then investigated in detail, also resorting to throughflow modeling, with the aim of integrating the preliminary sizing with the blade spanwise design. Finally, an assessment of the off-design turbine operation is also presented and discussed, so to characterize the impact of the seasonal variation on the turbine operation and efficiency. Despite the peculiar features of the organic fluids, the systematic optimization of the turbine allows to achieve high performance at both design and off-design conditions.
Characterization of ACC Losses Due to Wind and Design of Optimal Wind-Screens
Authors: Bianchini Cosimo , Da Soghe Riccardo , Giannini Lorenzo , Mazzei Lorenzo , Gardner Andrew , Wilde Jamie 
Published: September 2023

Abstract
Large mechanical draft Air-Cooled Condensers (ACC) are increasingly preferred, as a more environmentally friendly solution than wet cooling, in the cooling processes necessary to condense the working fluid in Rankine cycle-based power production systems. Such heat exchangers are conceived as an assembly of smaller modules each composed of an axial fan and inclined bundles where the fluid (usually steam) condensation actually takes place.
The fan is usually installed suspended above the ground at a height between 10 and 25 m, depending on the size of the ACC, with upward flow. Such a layout makes ACCs prone to a decay of efficiency and the onset of fan blade fluctuations due the crossflow induced by neighbour fans. Such detrimental effects become fundamental (up to 50% reduction in ACC cooling potential at 10 m/s), eventually resulting in fan failures, in case of high-speed winds.
Current work is devoted to the study of the wind effects on the cooling performance of the ACC and on blade load oscillations analyzing in detail the effect of wind speed and wind direction on a mid-sized ACC with 6 rows and 3 streets arrangement for 205.4 MW nominal thermal duty.
The study is conducted by means of high-fidelity CFD consisting of Unsteady RANS computations of the entire ACC with all 18 axial fans under rotation and a direct meshing of all the 6 blades per fan.
A common and relatively simple strategy used to mitigate such wind losses is the installation, directly on the ACC structural columns, of partially porous screens made of plastic fabric that act as wind breakers. The correct design of these wind screens is however quite challenging since they not only help reducing the wind speed below the ACC but also introduce additional aerodynamic losses that the fan needs to sustain to correctly feed the heat exchanger.
This study verifies the gains obtainable with the installation of wind screens, proposing a detailed investigation about different windscreen layouts (e.g. perimeter, cruciform, one-bay-back and skirt), variable screen porosity and dimensions.
Optimizing Micro Gas Turbine Operation in a Microgrid System With Natural Gas and Hydrogen Fuel: An AI-Based Approach
Authors: Banihabib Reyhaneh , Fadnes Fredrik Skaug , Assadi Mohsen , Bensmann Boris 
Published: September 2023

Abstract
In the coming years, decentralized power generation systems with renewables are expected to take a leading role, and micro gas turbines will serve as backup sources to compensate for times of low inputs from other sources. In order to deal with the unpredictable energy inputs from renewables, the micro gas turbine must be capable of running under varying load conditions and making fast transitions between them.
The operation of a micro gas turbine in an integrated microgrid has the potential to reduce operational costs and ensure the delivery of demanded heat and power to consumers. This paper investigates the operation of a micro gas turbine in a microgrid, serving as a supplementary power source for a municipal building. The building’s required energy is initially provided by wind turbine power, and the micro gas turbine serves as a backup source during times of wind power deficiency. The micro gas turbine can operate using a natural gas/hydrogen fuel blend ranging from zero to 100% hydrogen. Furthermore, a water electrolyzer with a hydrogen tank is available to operate as a storage system within the microgrid. The study’s results demonstrate the economic and environmental benefits of using hydrogen storage and optimizing operational planning in the microgrid. The primary objective of the paper is to highlight the feasibility and benefits of employing micro gas turbines and hydrogen storage systems within a microgrid as a renewable energy backup power source.
Effect of Entrance Cross-Section on Bulk Swirl and Performance of an S-Duct Inlet in High Subsonic Flow
Authors: Gilbart Ben , Asghar Asad , Allan William D. E. , Stowe Robert , Pimentel Rogerio , Pistun Timothy 
Published: September 2023

Abstract
For fuselage embedded engines, S-shaped ducts with multiple bends are usually employed to induct oncoming air. The combination of bends and diffusion creates a flow that routinely separates in regions of high-pressure gradient causing a concomitant reduction in static pressure recovery, a drop in total pressure, flow distortion and swirl at the engine face: the aerodynamic interface plane. This affects engine performance, stability margin, and safety of the integrated aircraft-engine system. It has previously been established that for a symmetric S-duct with a rectangular entrance, exit flow showed the presence of counter-clockwise, 10° bulk swirl. It was attributed to the axial transition of cross-section from a rectangular entrance to a circular exit and/or to high entrance Mach number. The present tests are done to investigate the exit flow bulk swirl and S-duct performance at Ma = 0.80 using a circular entrance. In addition, a 0.48 offset-to-length ratio, rectangular-entrance S-duct was tested at Ma = 0.80, 0.60 & 0.40. The S-duct was rapid prototyped in plastic using 3D printing. Stream-wise static surface and exit total pressure were measured using static taps and a 5-hole probe, respectively. The measured parameters were used to determine static pressure recovery, total pressure loss, exit flow swirl and pressure field polar distortion. These experiments provided information on flow mechanism and the evidence of the origin of bulk swirl in a symmetric S-duct with rectangular entrance.
An Analysis of the New ISO 23247 Series of Standards on Digital Twin Framework for Manufacturing
Authors: Shao Guodong , Frechette Simon , Srinivasan Vijay 
Published: September 2023

Abstract
ISO has recently issued a series of standards (ISO 23247) that deals with a digital twin framework for manufacturing. It is a generic framework that can be specialized to enterprises engaged in different manufacturing processes, such as discrete, batch, or continuous. This paper presents an analysis of this series of standards with two main objectives: (1) to inform the manufacturing community at large and (2) to examine this series of standards for applications in emerging industry sectors (e.g., biomanufacturing) and with novel manufacturing technologies (e.g., additive manufacturing). It takes a bottom-up approach, dealing with key terms and concepts first and gradually building up the framework. It includes interpretations and analyses to guide an appreciation of what the ISO 23247 series standardizes and the space it opens up for further development and industrial application.
Fatigue Study of Ti-6Al-4V Fabricated by Laser Powder Bed Fusion: Role of Defect Structure and Residual Stress
Authors: Hosseini Seyedmehrab , Vaghefi Ehsan , Mirkoohi Elham 
Published: September 2023

Abstract
Since the start of the second wave of digital manufacturing, the emergence of additive manufacturing (AM), there have been numerous efforts to explore and establish the linkages between process parameters and the mechanical behavior of additively manufactured metals. Among mechanical properties, fatigue life has received much more attention because of its importance in load-bearing applications. On the other hand, decisive factors like residual stress and defect structure hinder the applicability of AM components from being used in mission-critical load-bearing applications. This paper studies defect structure and residual stress’s impact on fatigue life as a necessary step to understanding the criticality of these factors on fatigue performance of Ti-6Al-4V components manufactured via laser powder bed fusion (LPBF). X-ray computed tomography (XCT) and X-ray diffraction (XRD) were performed to characterize the residual stress and defect structure of AMed Ti-6Al-4V specimens. Next, the samples underwent fatigue testing to correlate the XCT and XRD data to fatigue life. The residual surface stress showed a substantial effect on fatigue life. An obvious reduction was observed in fatigue life with the increase of residual surface stress in both scan and build directions. Additionally, average residual stress tends to reduce the fatigue life, but with a scattered behavior. Furthermore, a significant relationship between defect size and fatigue performance was observed. Maximum defect size showed a strong linear impact on fatigue life reduction. Also, a gradual decrease of fatigue life with average defect size was realized.
Development of a Model for Prediction and Optimization of Hardness of Electrodeposited Cu/SiC Composite Using RSM and ANN-PSO
Authors: Rai Prince Kumar , Gupta Ankur 
Published: September 2023

Abstract
Nanocomposite coating has a substantial impact on thermomechanical characteristics. There are several methods for developing nanocomposite coatings; however, electrodeposition is one of the additive manufacturing approaches that has been shown to be suitable due to its adjustable parameters, cost-effective and ease of process. Copper composite coatings have been extensively utilized in the aerospace and automotive industries due to their superior mechanical, electrical, and thermal properties. In the proposed study, a “In-house pulse electrodeposition setup” was developed and used to effectively deposit Cu/SiC nanocomposite coatings from an aqueous sulphate solution. Scanning electron microscopy (SEM) and x-ray diffractometer (XRD) are used to examine the surface morphology, which confirmed the successful co-deposition. The microhardness of the Cu/SiC composite coatings and effect of process parameters is predicted using response surface methodology (RSM). Artificial neural network-particle swarm optimization (ANN-PSO) is used to train, test, and validate experimental data and to investigate the correlation between electrodeposition process parameters and their effects on microhardness. The process was operated at: pulse frequency (10 Hz-100 Hz), duty cycle (20–80%), bath agitation (200–500 rpm), and SiC concentration (1–5 g/L). The determination coefficient (R2), root mean square error (RMSE), mean bias error (MBE), and mean absolute percentage error (MAPE) is used to validate several ANN-PSO models. The optimal morphology with the highest microhardness is produced under the following conditions: 10 Hz pulse frequency, 50% duty cycle, 350 rpm bath agitation, and 5 g/L SiC concentration. The findings showed that the suggested model is an appropriate, flexible, and reliable way for estimating the microhardness of Cu/SiC nanocomposite coatings.
Combining Agent Based Modeling and System Dynamics to Investigate the Circularity of Plastics
Authors: Sethuraman Sandhya , Walzberg Julien , Ghosh Tapajyoti , Uekert Taylor , Carpenter Alberta 
Published: September 2023

Abstract
The United States currently produces about 1 million metric ton of ocean plastic pollution annually. One proposed solution to combat plastic waste is a circular economy (CE), which aims to transition from today’s take-make-waste linear pattern of production and consumption to a system where the value of resources is maximized over time. Two key methods in industrial ecology are useful in assessing the viability of CE: (1) System Dynamics (SD) and (2) Agent Based Modeling (ABM). In prior work, the plastic life cycle was modeled with SD and ABM. The two models calculate recycling rates and costs in different ways, making it difficult to pinpoint necessary next steps. We integrate the ABM and SD models — linking the emergent patterns from micro-level human decisions to system level processes — which allows a more comprehensive understanding of feedbacks, costs, and environmental impacts. The integrated model is more accurate, and can be used to visualize recycling rates and human health and environmental impacts over time. The difference between the integrated and original SD model prompts a Sobol sensitivity analysis, which is used to understand which behavioral factors most affect plastic recycling patterns. We find that the habitual component is typically the most influential in promoting positive recycling behavior. Additionally, we utilize the combined model to understand and visualize how various behavioral intervention scenarios, like improved access to recycling programs and cart tagging, influence recycling patterns; these results can guide future policy-making.
Manufacturing Processes of Implantable Microelectrode Array for in Vivo Neural Electrophysiological Recordings and Stimulation: A State-of-The-Art Review
Authors: Yi Dongyang , Yao Yao , Wang Yi , Chen Lei 
Published: September 2023

Abstract
Electrophysiological recording and stimulation of neuron activities is important for us to understand the function and dysfunction of the nervous system. To record / stimulate neuron activities as voltage fluctuation extracellularly, microelectrode array (MEA) implants are a promising tool to provide high temporal and spatial resolution for neuroscience studies and medical treatments. Design configuration and recording capabilities of the MEAs have evolved dramatically since their invention and manufacturing process development has been a key driving force for such advancement. Over the past decade, since the White House Brain Research Through Advancing Innovative Neurotechnologies (BRAIN) Initiative launched in 2013, advanced manufacturing processes have enabled advanced MEAs with increased channel count and density, access to more brain areas, more reliable chronic performance, as well as minimal invasiveness and tissue reaction. In this state-of-the-art review paper, three major types of electrophysiological recording MEAs widely used nowadays, namely microwire-based, silicon-based, and flexible MEAs, are introduced and discussed. Conventional design and manufacturing processes and materials used for each type are elaborated, followed by a review of further development and recent advances in manufacturing technologies and the enabling new designs and capabilities. The review concludes with a discussion on potential future directions of manufacturing process development to enable the long-term goal of large-scale high-density brain-wide chronic recordings in freely-moving animals.
Prediction of Substrate Distortion in Powder DED Using Finite Element Model
Authors: Burl Alan G. , Fletcher Joseph , Saldaña Christopher 
Published: September 2023

Abstract
Leveraging the capabilities of both additive and subtractive manufacturing to repair tooling and other high value items can result in significant cost and time saving opportunities. However, when dimensional accuracy of the repaired component must be held within a specified tolerance, distortion of the component induced during repair can lead to an out of specification final component. This work presents simulation of a novel method to mitigate part distortion using sacrificial support structures. A blown powder directed energy deposition system was utilized for deposition of sacrificial support structures and clad surface depositions. Sacrificial support structures were deposited on the underside of the substrate with varying geometries prior to clad surface depositions. A finite element model was developed and verified using experimental results. The simulation and experimental control results were found to match within 6%. It has been shown that simulation can be used to predict effects of sacrificial support structures on substrate distortion in a blown powder directed energy deposition process.