bluuebunny/crossref_metadata_2025 huggingface dataset:
Failing Forward in European Economic Governance: The Cyclicality of European Integration and Institutional Competition in the COVID‐19 Crisis
Authors: Abels Joscha
Published: February 2024

The European Union's (EU's) response to the pandemic has been accompanied by reconfigurations in its institutional hierarchy, affecting the sites where institutional reforms are prepared and implemented. Whereas the Eurogroup drove reform during the euro crisis, the Commission had a more pronounced role in the development and implementation of pandemic instruments. This article ties in with failing‐forward arguments that view European integration as cyclical, arguing that this cyclicality also concerns the institutional dynamics in European economic governance. Based on expert interviews, official documents and reports, the analysis reconstructs and compares the institutional configurations during the euro crisis and the pandemic. Its findings suggest three modifications to ‘failing forward’: first, incomplete intergovernmental decisions are often the result of dominant particular interests rather than ‘lowest common denominator’ solutions; second, supranational bodies can exploit the delegitimization of intergovernmental solutions; and third, ad hoc measures can prolong the failing‐forward cycle and displace lasting integration steps.
Wheat germ meal replaces cottonseed meal at different levels in diets of Ossimi lambs: Impact on growth performance, feed utilization and economic efficiency
Authors: Hassan Ola G. A. , El‐Garhy Gamal M. , Kholif Ahmed E. , Mousa Gamal A.
Published: February 2024

This experiment aimed to evaluate the replacement of cottonseed meal (CSM) with wheat germ meal (WGM) in diets of growing lambs on feed utilization and growth performance. Twenty‐eight Ossimi male lambs (38 ± 0.8 kg weight), and 180 ± 5 days were divided randomly into four experimental groups in a complete randomized design for 105 days. Cottonseed meal was replaced with WGM at 0 (WGM0 treatment), 50 (WGM50 treatment), 75 (WGM75 treatment) and 100% (WGM100 treatment). The chemical analysis of the total essential and non‐essential amino acids showed an increase at the WGM diet compared to CSM. The replacement of CSM with WGM linearly and quadratically improved (p ˂ 0.05) lambs' growth performance and feed conversion. The WGM50 and WGM100 treatments lowered (p ˂ 0.05) feed intake, without affecting nutrient digestibility or diets' nutritive. Feeding WGM increased (p ˂ 0.05) total protein, albumin, and urea‐N concentrations in blood of lambs. The WGM100 treatment showed the highest relative percentage of net revenue compared to the other treatments. It is concluded that the complete replacement of CSM with WGM showed positive effects on lambs' performance and economic efficiency.
Meta‐analysis and machine learning reveal the antiobesity effects of melatonin on obese rodents
Authors: Li Yuying , Sun Xihang , Wang Mansheng , Jiang Yayun , Ge Qian qian , Li Tiejun , Hou Zhenping , Shi Pengjun , Yao Kang , Yin Jie
Published: February 2024

Melatonin appears to be a promising supplement for obesity treatment. The antiobesity effects of melatonin on obese rodents are influenced by various factors, including the species, sex, the dosage of melatonin, treatment duration, administration via, daily treatment time, and initial body weight (IBW). Therefore, we conducted a meta‐analysis and machine learning study to evaluate the antiobesity effect of melatonin on obese mice or rats from 31 publications. The results showed that melatonin significantly reduced body weight, serum glucose (GLU), triglycerides (TGs), low‐density lipoprotein (LDL), and cholesterol (TC) levels in obese mice or rats but increased high‐density lipoprotein (HDL) levels. Melatonin showed a slight positive effect on clock‐related genes, although the number of studies was limited. Meta‐regression analysis and machine learning indicated that the dosage of melatonin was the primary factor influencing body weight, with higher melatonin dosages leading to a stronger weight reduction effect. Together, male obese C57BL/6 mice and Sprague–Dawley rats with an IBW of 100–200 g showed better body weight reduction when supplemented with a dose of 10–30 mg/kg melatonin administered at night via injection for 5–8 weeks.
Suppression of non‐native and native grass seed germination using mustard seed meal and mulch biofumigation
Authors: Sencenbaugh Lilly , Mangold Jane M. , Ulrich Danielle , Rew Lisa J.
Published: February 2024

Non‐native annual grasses have invaded western rangelands in the United States, and novel approaches are needed to supplement existing management strategies. The aim of this study was to investigate biofumigation, the use of Brassicaceae products to suppress weeds, as a control for two non‐native annual grasses (cheatgrass, Bromus tectorum and ventenata, Ventenata dubia) and its effects on two dominant native perennial grasses (bluebunch wheatgrass, Pseudoroegneria spicata and Idaho fescue, Festuca idahoensis). We tested the effect of the biofumigant Brassica juncea (brown mustard), applied as seed meal and mulch, on germination metrics of the four grass species in Petri dishes. Germination metrics included emergence and viability, time to cotyledon and radicle emergence and their lengths at 14 days after sowing. Impacts on emergence and viability were assessed using a binomial mixed effects model, while time to cotyledon and radicle emergence and lengths were assessed using linear mixed effects models. Seed meal reduced emergence and viability at lower application rates for V. dubia and F. idahoensis than the other two species. Mulch did not consistently reduce emergence or viability. P. spicata was the least inhibited by the biofumigants. When using seed meal, radicle emergence and length were inhibited in B. tectorum, V. dubia and F. idahoensis and cotyledon emergence and length were inhibited for all. The mulch did not impact these metrics consistently and may not be a viable management tool. The use of seed meal biofumigant to suppress undesired annual grasses in rangelands seems promising, but response is species‐specific.
A Comparative Analysis of Gender and Public Opinion on Democracy in Poland, Romania, and the United States, 1995-2020
Authors: Hanson Sandra L. , Kelso Michelle , Tuch Steven A.
Published: February 2024

Research on attitudes toward democracy in Poland and Romania is timely given 2019’s three-decade anniversary of freedom from communism in Central and Eastern Europe. The U.S. makes an interesting comparison case given its history involving the American Dream and the Dream’s essential component of democracy. Using the World Values Surveys and a conceptual framework linking gender and democracy attitudes, we examine beliefs about democracy in Poland, Romania, and the U.S. between 1990 and 2020. Findings show significant cross-country, cross-time, and cross-gender variation on most of the belief measures and, contrary to much previous research, Americans do not always provide the strongest support for democracy. We conclude that simple assumptions about American exceptionalism on democracy attitudes are often inaccurate, as are assumptions that women are universally more positive about democracy than men. Consensus on democracy related attitudes in Romania and Poland is also not supported by our results, suggesting that unique historical, political, and socio-economic experiences among formerly communist nations play an important role in shaping beliefs about democracy.
Reviewer Acknowledgements for International Journal of Social Science Studies, Vol. 12, No. 1
Authors: Young James
Published: February 2024

International Journal of Social Science Studies (IJSSS) would like to acknowledge the following reviewers for their assistance with peer review of manuscripts for this issue. Many authors, regardless of whether IJSSS publishes their work, appreciate the helpful feedback provided by the reviewers. Their comments and suggestions were of great help to the authors in improving the quality of their papers. Each of the reviewers listed below returned at least one review for this issue. Reviewers for Volume 12, Number 1Aurora Pestaño, University of San Jose Recoletos (USJR), PhilippinesEncarnación ABAD ARENAS, National University of Distance Education (UNED), SpainIvan Lenard, Elementary school Ladimirevci, CroatiaJehu Onyekwere Nnaji, University of Naples II,Italy and Globe Visions Network Italy, ItalyJibrin Ubale Yahaya, National Open University of Nigeria NOUN, NigeriaMei-Ling Lin, National Open University, TaiwanNadarajah Pushparajah, University of Jaffna, Sri LankaSana Ali, Allama Iqbal Open University, Islamabad, Pakistan James YoungEditorial AssistantOn behalf of,The Editorial Board of International Journal of Social Science StudiesRedfame Publishing9450 SW Gemini Dr. #99416Beaverton, OR 97008, USAURL: http://ijsss.redfame.com
Method to Backout Load From Strain Gauges Using Machine Learning
Authors: Chinthapally Srinivas , Nuli Sidhardha , Das Arnab , Hedaoo Akshay
Published: February 2024

During vibration tests, loads need to be measured for machine components such as bearings, mounts, lugs, etc. As load cells cannot be placed at certain locations in the interior, strain gauges are used instead to measure the strain. But we need a load strain relation for the components. Most of the real-life components experience axial, bending, and torsional loads. Hence a multi-dimensional force strain relationship needs to be established for each component. Hence, prior to the actual tests, calibration tests are performed, on each component separately. These calibration tests are most often static load tests, in which load is applied in one direction at a time in small increments of load. In addition to the unidirectional loads, combined loads are also applied to establish complete load strain surface. Multidimensional load strain data is compiled and pre-processed to develop a multivariable load-strain relationship. The load-strain relationship is later used to back out loads from the strain data. Currently methods such as Newton-Raphson, plate smoothing spline, surface fitting, etc. are used to develop this relationship. Newton-Raphson is an iterative technique which solves for the loads simultaneously at each strain points. This method iterates till the error is small to achieve convergence. Newton-Raphson and surface fitting methods require structured data for developing multivariable load-strain relationship. However, deriving load-strain relations for complex geometries exhibiting highly nonlinear relationships is mathematically complex and computationally expensive. Also, formulation of these methods limits the use of large number of variables (more than 3). In this paper, an ensemble of MARS (Multi variate adaptive regression spline) along with Adaboost boosting algorithm has been explored to predict loads from strain data by developing multivariable correlation between loads and strains. MARS is an improved multivariable spline regression technique that generates piecewise polynomial functions between the variables and automatically determines the number & size of segment to achieve high accuracy or best fit on nonlinear problems. With complex high dimensional and noisy non-linear problem, Adaboost helps to reduce overfitting and improve the performance of the MARS model. The proposed method is well suited for dealing with large number of variables and developing complex non-linear load-strain relationship as it doesn’t require any structured data or iterations like existing methods to backout loads. The proposed method reduces the run time by more than 90% as compared to the conventional methods without compromising on accuracy. The advantages of the proposed method over conventional techniques have been demonstrated in this paper.
Influence of Concentrated Augmenter on the Performance of a Two-Bladed Savonius Wind Rotor Composed of Arc-Elliptical Profile
Authors: Alom Nur , Talukdar Parag K. , Sarkar Bikash Kumar , Saha Ujjwal K.
Published: February 2024

The Savonius wind rotor, a drag-based vertical-axis wind turbine, is gaining importance throughout the globe as a way to generate electricity while reducing global warming. Although it exhibits a lower performance, this type of rotor is gaining immense interest in the research community because of its straightforward design, self-starting capability, and operational ease. Over the past two decades, numerous blade profiles have been created to improve the performance of this rotor. A recently developed arc-elliptical blade profile has shown an improved performance characteristic. In the present computational study, this arc-elliptical blade profile is considered with a concentrated augmenter placed in front of it. The concentrated augmenter is placed to enhance the performance of the blade profile further. The arc-elliptical blade profile with the concentrated augmenter is investigated using a commercial computational fluid dynamic solver ANSYS Fluent 17.1 with the help of shear stress transport (SST) k-ω turbulence model. The torque and power coefficients of the augmented rotor have been evaluated for a range of tip-speed ratio. The results obtained in the present study are also compared with those of the arc-elliptical blade profile without the concentrators. An enhancement of CPmax by 4.11% is observed in the arc-elliptical bladed rotor with the concentrated augmenter as compared to the one without the augmenter.
Evaluation of Scaling Formation on Entropy Generation of Flowing Fluid Through Circular Pipe
Authors: Singh Onkar , Maheshwari Mayank
Published: February 2024

The generation of entropy leads to destruction in performance of the thermodynamic element. The present paper investigates the entropy generated in a heat exchanger under different operating conditions and varying scale thickness. The results show that with increase in scale thickness entropy generation increases. The entropy generated is maximum when the effect of temperature is considered and corresponds to 9.9J/K for a scale thickness of 1mm. Entropy of 6.6J/K and 7.8J/K is generated respectively for Nusselt number 7.5 and Stanton number 4 when scale thickness is 1mm. The effectiveness of heat exchanger decreases by approximately 2% for an increase of 1mm scale thickness. If the scale thickness is neglected then the entropy generated is observed to be 4J/K, 2.1J/K, and 2.6J/K respectively for the same operating conditions.
Improving the Stage Efficiency of Axial Compressors by Vane Rotation
Authors: Ajith Pisharam Akhila , Raja Vijayanandh , Raji Arul Prakash , Madasamy Senthil Kumar
Published: February 2024

There are currently many methods to overcome axial compressor stall. This phenomenon affects the compressor rotor at a great level and hence is of much concern. One method is to control the rotor tip clearance by certain criteria. No rotor tip clearance is ideal, but the general clearance is two millimeters. But modifying the rotor tip clearance requires changes at the design level and is difficult if planned to implement on an already functional model. Hence, a new method is being proposed to improve the stage efficiency and to increase the performance under adverse conditions. This research proposes to give selected stator vanes the capability to rotate by 360 degrees. This rotation shall be normal to the direction of incoming airflow, i.e., axial. The concept of variable stator vanes is currently being used in axial compressors to delay the stall onset and to streamline the flow direction. The mechanism mentioned here will follow a similar purpose with similar principles. The research provides computational results of the same. First, using moving reference frame, the rotation is simulated, and the velocity profile is found to increase. Next, using transient state with moving mesh, the entire stator is designed and selected blades from that are rotated to prove the effectiveness of the method. The velocity and pressure variations are analyzed to identify the effectiveness of this method. The materials’ reaction to these modifications in the operation procedure is also determined. Hence, it is found that the rotation of the stator vanes will provide the necessary momentum for the air to not stall and to maintain the airflow at a speed that is not ideal with a lower mass flow rate, but enough to prevent the air from stalling.
A Strategic Design Approach for Future Fuselage BLI Engine Based Hybrid Propulsion Engine
Authors: Mistry Chetan S. , Kolhe Surendra Kiran , Raj Harsh , Bharade Aditya , Anantwar Jay , Mandal Goutam , Agrawal Abhishek
Published: February 2024

This research paper presents the systematic design approach for a hybrid electric propulsion system using the concept of fuselage BLI (Boundary Layer Ingestion). Various BLI configurations were explored and a rear mounted axisymmetric configuration for the BLI engine was chosen for present study. CFM56-7B24 engine was selected as the baseline engine and the performance of the engine was replicated using the GasTurb 14 software. GasTurb electric module was used to integrate an electric propulsion system with the gas turbine engine and detailed parametric studies for the newly proposed engine were conducted to optimize important performance parameters. The amount of power to be extracted from the primary (underwing) engines to run the BLI fan on the design point was decided by a systematic trade-off study between the net TSFC and the mass of the electric propulsion system, where net TSFC is defined as the ratio of total fuel consumed and the sum of thrusts generated by the primary engines and the aft-body BLI fan. A significant decrease in net TSFC was observed at the design point. To meet the high efficiencies and power requirement, HEMM (High-Efficiency Megawatt Motor) was chosen for running the electric fan. GasTurb’s inbuilt feature was used for estimation of weight for the newly configured engine. A simple mission was generated to compare the performance of the baseline engine with the newly proposed engine and to analyse the performance maps of compressors and turbines. The operating line for the simple mission was plotted over the maps of compressor and turbine to assess their performance throughout the mission. The newly proposed engine was then simulated at off-design conditions in GasTurb. An impressive 13% fuel benefit was observed due to the incorporation of BLI and hybrid operation compared to the baseline engine. This study demonstrates the feasibility of a hybrid electric propulsion system using BLI and provides insights into the design and manufacturing of individual components. The results obtained can thus serve as a valuable reference for future studies in the field of hybrid aircraft propulsion systems.
Effect of Pivot-Shape Modification on Part Clearance Flow Field in Variable Area Turbine Nozzle Vane
Authors: Mandal Goutam , Bhavsar Hardikkumar , Mistry Chetan S.
Published: February 2024

The aim of the study is to investigate and mitigate the secondary losses in a variable turbine area nozzle vane by modifying its pivot shape. The variable area nozzle vane (VANT) is used to actively control the mass flow rate and improve the off-design performance of the turbine stages. However, the clearance required for the pivot mechanism introduces tip leakage losses, which can render the benefits of the variable area nozzle vane useless.

The study uses the 2nd stage of low-pressure turbine vane from the Energy Efficient Engine proposed by Pratt and Whitney. The vane passage is modified to implement the VANT concept, and the effect of different pivot profiles and modifications on the bottom surface near the suction side is investigated at various setting angles. The numerical simulations are performed using Ansys ICEM CFD® and ANSYS CFX®, and the results are analyzed using parameters such as non-dimensional vorticity, static entropy, and total pressure loss coefficient.

The study shows that the improvement upon introduction of shape modifications to the pivot, a) elliptical passage in pivot b) tapered pivot, reduces the total pressure loss coefficient by 4% as compared to the vane passage with unmodified circular pivot. The interaction between the leakage flow and the main passage flow is also observed using three dimensional streamlines. Overall, the study provides insights into the sources of secondary losses in variable turbine area nozzle vanes and demonstrates that modifying the geometrical shape can help mitigate these losses and improve the efficiency of the turbine.
Computational Investigations of Effect of Reynolds Number on Secondary Losses and Flow Behavior in Linear Turbine Cascade
Authors: Darji Anand P. , Baloni Beena D. , Mistry Chetan S.
Published: February 2024

Secondary losses in modern gas turbines are one of the challenging factors among turbine designers and manufacturers which significantly impact the overall gas turbine performance. This study is aimed to provide an insight of the mechanism underlying the secondary loss contribution with the variation of Reynolds Numbers. Firstly, the baseline secondary flow losses are investigated for the 2nd stage low-pressure turbine (LPT) vane root profile of the energy efficient engine (E3) developed by Pratt & Whitney using numerical simulations. Then, the effect of various vane exit Reynolds Numbers ranging from 0.7 × 105 to 6 × 105 on the end wall secondary losses are investigated. The results indicate that the total pressure loss of the linear turbine vane cascade increases with the lower operating Reynolds Number. At higher Reynolds number, the passage vortex and wall-vortex induced by passage vortex shows span-wise extension and limits the passage extension which results in lower secondary loss. Compared to the baseline case, the study showed an increase of approximately 1.5 times for Re = 0.7 × 105 and a reduction of 4% for Re = 6 × 105 in the total pressure loss coefficient at the measured plane downstream of the trailing edge.
New Tip for More Efficient and Less Environmental Impact Gas Flaring Process
Authors: Kamel Ahmed H. , Alzahabi Ahmed , Romero Yazmin
Published: February 2024

The oil and gas industry is constantly evolving, aiming at producing more energy at lower cost with fewer emissions and minimum impacts on the environment. One of the main sources of emission is gas flaring.

Gas flaring involves burning off excess gases using a flare stack, that is a critical piece of equipment designed to release and burn gases and other materials from pressure-relief and vapor-depressurizing systems safely and efficiently. Flares and their mechanical components should be designed to operate properly and reliably for considerably extended periods under specified service conditions. The combustion process occurs through a diffusion flame, which may produce smoke if there is a lack of oxygen and/or carbon particles cool below their ignition temperature. The primary difference between flares is their ability to mix flared gas with oxygen.

Gas flaring is one of the most controversial and challenging environmental problems faced today regionally and globally. Gas flaring has had a significant impact on the environment such as pollution, global warming, and economic losses. It is responsible for wasting about 5% of the global gas supply where more than 350 million tons of CO2 gas are produced annually. There are many alternatives for gas faring. Flared gas can be converted into electricity via turbines, and gas-to-liquid (GTL) Technology. Also, Flue gas can be used for EOR. However, they are either under investigation or not economically viable. Therefore, a more efficient gas flaring system is crucial.

In this paper, a new gas flaring tip believed to alleviate the challenges of other flaring systems is presented. The tip itself is a unique design due to a bullet device seated on top of the flare. The bullet device has four holes with inside deflectors to push the gas to a single outlet at the top in a vortex. The bullet is attached to the flare tip with three springs that allow it to lift with 2 psig and to extend fully at 8 psig. This design will allow gas to travel around the bullet using the Coanda effect and ensures efficient oxygen.

The tip was evaluated over a wide range of gas capacities. Thermal radiation, isopleths, and noise levels were measured. In addition, flue gas composition and combustion efficiency were investigated. The results prove the new tip is superior to the existing gas flaring systems. As a cost-effective, smokeless tip with higher efficiency and cleaner flames, the authors recommend the new design to minimize flaring environmental impacts.
Exploration of Recovering Waste Heat in a Cascade Liquefied Natural Gas (LNG) Plant
Authors: Acharya Shisir , Wang Ting
Published: February 2024

Natural gas (NG) has lower and cleaner emissions compared to other fossil fuels such coal and petroleum, thus NG gas has been widely used in recent years to replace coal, diesel, or other petroleum derived fuels to generate power. However, many nations in the world have limited or minimal NG resources, importing liquefied Natural Gas (LNG) has become the only method for countries where transporting natural gas through land-based piping is not sufficient or not available, for example, like Japan, South Korea, Taiwan, Pakistan, to name a few.

LNG can be obtained when natural gas is refrigerated to the temperature around −260°F (−162°C). At this temperature, the original volume of the natural gas is reduced by 600 times. To reach this temperature, a multistage refrigeration system with intercooling and regeneration is required. The process of producing LNG is an energy intensive process, which demands a large amount of compression from multiple compressors. Each of these compressors is directly driven by a gas turbine. The gas turbine exhaust contains a large amount of useful energy, but often it is released into the atmosphere and ultimately wasted. The objective of this study is to identify methods to utilize this hot wasted exhaust and recover energy from it. This paper first provides a generic review of various existing commercial LNG production processes. Then a cascade LNG process is simulated to utilize up to four succeeding (cascading) vapor compression refrigeration loops to achieve the cryogenic temperature around −260°F (−162°C). This exhaust has been combined and the energy has been recovered through a Heat Recovery Steam Generator (HRSG). This recovered heat through HRSG has been utilized to run a Rankine cycle power plant to produce electricity. The results show that the wasted heat recovery system combined with a Ranking cycle can recuperate up to 47% of the wasted energy.
Photo-Switchable Optical Property of Two-Dimensional Transition Metal Dichalcogenides
Authors: Cunningham Connor , Pillai Srajan , You Jeong Ho , Ji Jaehoon , Choi Jong Hyun
Published: February 2024

Transition metal dichalcogenides (TMDCs) have received much attention for optoelectronic applications because of their band gap transition from indirect to direct as they decrease from multilayer to monolayer. Recent studies have experimented with the use of photochromic molecules to optically control the charge transport of two-dimensional (2D) TMDCs. In this work, a numerical study using density functional theory has been performed to test the possibility to control the optical property of 2D TMDC monolayers with various photochromic molecules. When the photochromic molecule’s highest occupied molecular orbital (HOMO) or lowest unoccupied molecular orbital (LUMO) energy levels are within the band gap of 2D TMDC monolayers, holes or electrons will transport to the photochromic molecules, resulting in the reduction of excitons in the 2D TMDC monolayers. The reduced optical response can be recovered by going through reverse isomerization of the photochromic molecules. Molybdenum disulfide (MoS2) and tungsten diselenide (WSe2) monolayers were tested with various photochromic molecules including azobenzene, spiropyran, and diarylethenes (DAE 2 ethyl, DAE 5 ethyl, DAE 5 methyl). The systematic study presented in this work displays that MoS2-Spiropyran and every diarylethene derivative used in this study except MoS2-DAE 5 methyl exhibited photo-switchable behavior.
Comparative Electrode Design for Piezoelectric MEMS Kinetic Energy Harvester
Authors: Janardhana Ranjith D. , Jackson Nathan
Published: February 2024

Microsystem based piezoelectric kinetic energy harvesters have been extensively investigated over the past decade. The most popular structure of these devices includes a cantilever consisting of a substrate, and a parallel capacitor (electrode/piezoelectric/electrode) layout. This type of structure has the ability to harvest energy by working in the d31 mode where the electrical potential is taken in the 3 (out of plane direction) while the strain/stress occurs in the 1 (in plane direction) direction. However, the d31 piezoelectric properties are approximately half the value compared to the d33 mode. Therefore, operating in the d33 mode should result in increased power output. A ferroelectric material that is able to alter its polarity is needed to investigate this potential design enhancement. This paper investigates the performance of both parallel plate capacitor and interdigitated electrode MEMS energy harvesters using lead zirconate titanate thin films using finite element modelling and experimental results to demonstrate the increase in power density, and the effects of varying the electrode configurations and dimensions.
Effect of EIS in a 3D Printed Non-Planer Array Patterned Microfluidic Devices
Authors: Kabir Shanzida , Zepeda Saenz Hector , Islam Nazmul
Published: February 2024

In recent years 3D printing is becoming popular among researchers for its reliability, cost-effective materials, and ease of use without having costly clean rooms. In this work we report the process of fabrication of an array patterned microfluidic device with its effect in Electrochemical impedance spectroscopy (EIS) and particle manipulator. With the optimized design of channel geometry and electrode pattern, this device can use in different lab-on-a-chip applications. A 3D printed microfluidic channel fabrication process is presented here along with a CAD drawing with microstructural dimension analysis. EIS is an expeditiously developing method used in characterizing materials and interfaces. By using equivalent circuits as models, it can determine the electrical properties of heterogeneous systems like membranes or electrolytes. For evaluating Impedance spectroscopy, a small amount of perturbing sinusoidal signal was applied to the electrochemical cell and measured the resulting current response. We take EIS measurements in three different electrolytes DI water (18.72μS/cm), tap water (666.12 μS/cm), and PBS 1 × (8235.24 μS/cm) with three different ranges of conductivity to observe their characteristics changes and to compare them. We analyze the electric double layer (EDL) effect for the electrode and electrolyte interface and how electron transfer kinetics and diffusional characteristics affect the spectra EIS is applicable to determine different electrochemical processes that can happen at the same time. Also, using AC electrokinetic (ACEK) flow the device can be used as a potential microfluid manipulator with its array electrode pattern. Both the micro-PIV and EIS experiments were done to verify the data validity of the microfluidics mixers.
Condition Monitoring of Cutting Tools by Feature Analysis of Vibro-Acoustic Sensing Signals
Authors: Lao Dongjing , Shen Yanfeng
Published: February 2024

This paper presents a vibro-acoustic sensing method for real-time Tool Condition Monitoring (TCM) for Computerized Numerical Control (CNC) machining. The method captures Contact Acoustic Nonlinearity (CAN) arising from periodic impacts between the cutting teeth and the workpiece to obtain the spectral domain characteristics of sensing signals captured by piezoelectric transducers. The tool wear evaluation metric is constructed, starting with analytical modeling of cutting signals using a nonlinear oscillator model. Numerical case studies are conducted where a periodic impact vibration signal is simulated and fed into the equivalent CAN reduced-order nonlinear oscillator model of a machine tool system to predict the dynamic response. Thus, the nonlinear response spectrum is obtained and the mechanism behind the spectral nonlinear characteristics is illustrated by simulating various wear severities and breakage situations of the cutting tool. Furthermore, nonlinear features are extracted from the vibration response acquired during CNC machine tool machining by low-cost piezoelectric sensors to diagnose the tool damage. Several damage indices are explored to quantify the severity of the damage, relating to spectral nonlinear features such as shifts in the position of the dominant frequency, increase in mixed-frequency response components, and generation of higher-order harmonic components. The analytical modeling results, the extracted non-linear features, and the damage index derived is validated against experiments and are able to effectively identify the severity of tool wears. The proposed method and findings provide a promising approach for the practical application in the field of smart manufacturing.
Identifying Sick Cells From High-Resolution Solid-State Micropore Data
Authors: Hafeez Abdul , Ilyas Azhar , Butt Ali R. , Iqbal Samir M.
Published: February 2024

Early detection of diseases such as cancer can drastically improve prognosis and treatment. To this end, solid-state micropores can measure distinct mechanical properties of diseased cells from their translocation behavior — detected as pulses in the temporal data stream of ionic current — and help diagnose diseases at early stages. However, the obstacle in such approaches is that the accuracy of the sensor is affected by noise, making the pulse detection task too subjective. This is inefficient especially when the disease-relevant data is only a fraction of the total acquired data. Thus, it is important to intelligently automate the detection process to eliminate the noise and to identify useful patterns towards error-free decision-making in real-time. This work describes a pattern detection approach based on moving-average filtering, which mitigates the impact of noise. Moreover, a detection threshold is computed from the mean and standard deviation of the data. The threshold is then used to detect different types of pulses stemming from the healthy and diseased human cells when these translocate through micropores. Extent of smoothing is an important factor for the data: greater smoothing suppresses the noise but deteriorates the pulse shape and vice versa. Additionally, the design approach computes useful features of the detected data and delivers the results for real-time analysis. This can help physicians and scientists to change their strategies of diagnosis by providing a validation of manual reviews.
Electronic Failure of Small Implantable Devices due to Moisture Ingress Through a Medical Grade Epoxy
Authors: Blue Simon , Munro Deborah
Published: February 2024

This article discusses the evaluation of hermeticity of epoxy-sealed enclosures for biomedical devices used inside the human body for long-term implantation. The aim was to prevent moisture ingress, which was evaluated under accelerated testing conditions with two medical grade epoxies, Loctite Hysol M-31CL and Master Bond EP40MED. A mathematical model was used to approximate the lifespan of a polymer-metal-epoxy encapsulation based on a desired maximum internal relative humidity of 55%. For small implantable devices, a humidity sensor often won’t fit in the available space, so a cobalt chloride paper was used inside the housing for this study, and a clear acrylic lid provided a viewport. The paper’s color changed from blue to pink at 55% relative humidity, and this was photographed and then evaluated with an algorithm to provide the daily average color value. The results showed that the type of adhesive was a critical factor in the expected lifespan for the device, and the EP40MED epoxy provided a superior lifespan against moisture ingress compared to the M-31CL epoxy. The study was limited by its interpretation of the color at which the internal relative humidity reached 55% as well as by slight variations in the lighting conditions for each day’s photograph of the paper. The results provide useful information for the design and development of biomedical devices at their final size under accelerated aging conditions and highlight the critical role that adhesives play in the expected lifespan of these devices inside the human body.
Sustainability and Recent Experimental Advances on the Production of Metallic Bipolar Plates of PEM Fuel Cell Using Electromagnetic Forming Technique
Authors: Karibeeran Shanmuga Sundaram , Rahiman Mohammed Abdul Kadar , Murugesan Pradeep Kumar , Justin Jebin Rex
Published: February 2024

The most troublesome challenge in overcoming the threats of energy crises, an eco-friendly energy source to replace fossil fuels greatly hinders the development of PEM fuel cells (PEMFC) with their ability to convert hydrogen gas and oxygen gas into electrical energy and water which offers clean, reliable, no pollutant and efficient power source in the automobile industries. The bipolar plates (BPPs) are one of the influential components of PEMFC, where the BPPs account for 60–80% of total weight and 45–60% of total manufacturing cost of PEMFC. The potential surplus of metallic bipolar plates is optimistic for replacing conventional carbon-based (graphite) BPPs while its cost is still relatively high. Manufacturing these plates through Electromagnetic forming (EMF) is highly suitable for mass production at Uniform pressure actuators. EMF is a technology of forming a conductive sheet metal workpiece at high speed without physical contact by applying a high-impulse electromagnetic field to the workpiece and no working medium is required. The EMF technique forming of metallic bipolar plates micro-channel was investigated in the Copper sheet metal of 200 μm. A large variant of serpentine-like flow field structures was constructed and evaluated by running 3D simulations of Ansys LS-DYNA.
Quantitative Imaging of Elongated Thickness Defects in Pipelines Using Ultrasonic Guided Wave Tomography
Authors: Rasgado Moreno Carlos Omar , Ratassepp Madis
Published: February 2024

Monitoring the wall thinning in pipelines is crucial in the energy industry to guaranty its proper operation. Typically, in pipelines where fluids with particles or solid particles are transported, larger erosion is encountered which is usually the same along the length of the pipe. Conventionally, Non-Destructive testing techniques for wall thinning are based on a local point-by-point ultrasonic measurements, which is slow and costly. In contrast, Guided Wave Tomography (GWT) based on Full Waveform Inversion (FWI) is an accurate and high-resolution reconstruction method, that enables the monitoring of the whole pipe area by processing the waves excited and received by transducer arrays. Although FWI have been used successfully to reconstruct small localized defects in the past, the reconstruction of the elongated defects remains a challenge as the waves propagating through the defect may undergo cycle-skipping effect which breaks down the inversion algorithm. In this study, the limits of FWI are explored when reconstructing elongated defects on a steel pipe with 6.5 mm in thickness, 230.2 mm in diameter and 720 mm in length. Four elongated Hann-shaped defects were modeled in a three-dimensional (3-D) finite element model, and reconstructed using FWI based on an acoustic two-dimensional (2-D) forward model. The defects have a 70 mm width, 1.5 mm in depth, and longitudes of 25%, 50%, 75% and 95% each of the pipe length. Two initial velocity-thickness models were considered, one homogeneous along the reconstructed domain and the other one with a velocity variation. The velocity-thickness variation model was based on the time of flight (TOF) of the transmitted signal of the aligned transducers. For 25% and 50% defects’ longitudes good agreement was found between 3-D finite element model and the 2-D reconstructed model, when the background initial velocity model was constant. In contrast, for defects with a longitude larger than 75% of the pipe’s distance, good agreement was found between 3-D finite element model and the 2-D reconstructed model when selecting a suitable initial velocity-thickness model.
Investigation of NH3/Air Laminar Burning Speed and Flame Structure at High Pressures
Authors: Alvarez Luis F. , Shaffer James , Dumitrescu Cosmin , Askari Omid
Published: February 2024

Understanding the effect of fuel properties on ammonia (NH3) flame characteristics is important for practical applications. This study investigated NH3/air mixture ignitability, flame morphology, and propagation rate in a constant volume combustion chamber (CVCC) at high-pressure conditions using high-speed schlieren imaging. Experiments were performed at an equivalence ratio, ϕ, from 0.7 to 1.3, initial pressures from 1 atm to 10 atm, and an initial temperature of 298 K. The study also used a novel filling method that accounts for the NH3 adsorption on the stainless steel CVCC surfaces. While the data analysis suggested that the NH3 adsorption was negligible, the CVCC passivation before the start of the experiments (i.e., allowing enough time for NH3 to adsorb on the chamber walls) reduced the experimental uncertainty with respect to the actual NH3/air (ϕ) inside the CVCC. More, the low speed of NH3/air flames can negatively affect flame stretch and laminar burning speed (LBS) calculations for mixtures at high initial pressures due to the significant buoyancy effects. Hence, a special method accounting for buoyancy was implemented to calculate the volume of the combustion products and, subsequently, to compute the LBS of the non-spherical NH3/air flames. The high-speed schlieren imaging showed that, as the pressure increased, the flames got smaller, indicating a decrease in speed and therefore an increase in buoyancy. Cellular structures were absent during the period of flame propagation inside the chamber. The conventional constant pressure methodology was used for the LBS calculations. Results indicated that for the evaluated conditions, the LBS increased with ϕ until reaching a maximum value for ϕ = 1.1. In addition, it was shown that as the initial pressure increased, the LBS value decreased, similar to the conventional trend seen for hydrocarbons LBSs.
An Experimental and Computational Study of Mechanically and Dynamically High Loaded Separators for Lithium-Ion Batteries
Authors: Bulla Marian , Sahraei Elham , Kolling Stefan
Published: February 2024

In recent years, the automotive market has been pushed to significantly reduce CO2 emissions and increase the development and production of electrically powered powertrains. Currently, the best industrial storage method for electric energy is the lithium-ion battery, which is already used in the automotive industry and in consumer electronics (e.g., cell phones and laptops). The Li-ion cell is considered the most promising energy storage source currently available on the market. Motor vehicles are exposed to various crash and abuse scenarios under different load conditions. With the increasing use of these batteries in vehicles, safety has become a concern due to unintended failures and accidents. For this purpose, a detailed study of the separator in terms of mechanical stiffness as a function of fabrication direction and loading rate was carried out. Based on the results a new material model was developed in which the orthotropic-visco-elastic and orthotropic-visco-plastic mechanical behavior of a polymeric material can be considered. In addition, based on uniaxial tensile tests with local strain measurement, a novel failure criterion for finite element analysis was developed to predict the effects of high mechanical loads in terms of triaxiality, large plastic strains, orthotropy and viscosity. Finally, a simulation model for a PE separator was developed combining the new failure with a G’Sell and Swift-Voce strengthening rule. This model was able to predict the anisotropic behavior of the PE separator during deformation and failure. The modeling method presented in this work allowed accurate prediction of the strength of the tested PE separator. The proposed new failure criterion predicted the failure strain for all three directions within a range of 3% and agreed very well with the tests performed. Some small deviations occurred due to the simplified boundary conditions as well as the influence of the element length. However, it should be noted that the real tests showed scatter in a much larger range. The quantitative comparison was made based on the elongation response at fracture of the three differently oriented specimens (MD, DD, TD). The present failure criterion and detailed calculation method should be useful in the development of batteries and be used as an important new computational tool for the for evaluating the safety of lithium-ion batteries under high mechanical load and crashworthiness. The proposed failure criterion can also be combined with other constitutive material laws. The results of these investigations are implemented in the failure model based on Elham Sahraei’s model (/FAIL/SAHRAEI) in the explicit crash solver OpenRadioss™.
Finite Element Analysis of 3D Printed Stand-Alone Transforaminal Lumbar Interbody Fusion Cages Under Various Loadings
Authors: Zhang Yufei , Kang Minjae , Su Siheng
Published: February 2024

With the development of 3D printing technology in the biomedical field, orthopedic implant designs such as transformational lumbar interbody fusion (TLIF) cage that were challenging to realize in the past have become a reality. The traditional metal lumbar interbody fusion cage would cause stress shielding and bone remodeling because of their relatively high Young’s modulus compared to natural bone. This study investigated the mechanical properties of TLIF cages produced by traditional method and 3D printing technology using finite element analysis (FEA) under five different body motions, including standing, lifting objects, lifting objects & forward bending, lateral bending, and forward bending. Stress analysis of traditional titanium alloy Ti-6Al-4V cage, 3D printed Polyetheretherketone (PEEK) TLIF cage, and 3D printed porous carbon fiber reinforced Polyetheretherketone (CFR-PEEK) with various infill densities by FEA showed the mechanical properties of 3D printed CFR-PEEK solid cage is comparable to Ti-6Al-4V cage with maximum Von-Mises stress of 12.391 MPa, total deformation of 0.0029257 mm under the ‘standing’ condition with a 1000N axial compressive force. The minimum factor of safety (SF) for Ti-6Al-4V cages are above 15 under all postures, while 3D printed PEEK solid cages under some postures are not reliable with a SF smaller than the recommended value of 2.0. On the other hand, SF for 3D printed CFR-PEEK porous cages was above 2.0 with an infill density 50% and above, demonstrating that 3D printed CFR-PEEK would be an excellent candidate for the lumbar cages.