bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Dual Environment Aging on Flexible Polyurethane Based Adhesive
Authors: Shaafaey Mamoon , Bahrololoumi Amir , Dargazany Roozbeh 
Published: February 2023

Abstract
Environmental degradation of adhesives naturally increases with the intensity of the ambient weathering agents involved. During service life, these materials are never subjected to a constant environmental loading. Real-time applications expose the material to multiple weather conditions, ranging from dry to humid or fully wet conditions. While some understanding exists about aging environments in isolation, we intend to investigate the effect of multiple environments on the constitutive behavior of the materials in question. The extent of damage can be accessed by analyzing the changes in constitutive behavior and toughness of aged material. Therefore, this aging experiment was designed around two-way aging regimes involving combinations of thermo-oxidation, hydrolytic and hygrothermal aging environments. We selected a polyurethane based flexible adhesive which is commonly used in the automotive industry as a glass sealant. The aged specimens were subjected to uniaxial tensile tests, and variation in material toughness and constitutive behavior was analyzed to ascertain the mechanics involved in the case of each environmental exposure. We outlined how different environments affect the material in isolation and how they interact with other weathering conditions. This study will help better understand and model the damage mechanics involved in exposure to multiple environmental conditions.
Developing a Consistent Resonance-Induced Fatigue Testing Method on Novel Freely Supported Specimens
Authors: Napper Lorean 
Published: February 2023

Abstract
A fatigue test employing vibration-based fatigue known as the “Free-Free” has been in use inside the Turbine Engine Fatigue Facility (TEFF) of the Air Force Research Laboratory. The vibration-setup utilizes free boundary conditions by suspending a specimen on its nodal line that when excited, allows for deflection in its first bending mode. The excitation source is an electromagnet coil that attracts and repels a permanent magnet located on the specimen. The experimental specimens, 0.4 mm cold-rolled Ti6Al-4V, are thin specimens representative of geometries that undergo large amounts of cyclic loading during system operations expected for supersonic and hypersonic aerospace technologies. The Free-Free offers an ideal solution to addressing key structural assessment needs for these critical technologies. In the past, the Free-Frees’ usage in the TEFF has resulted in inconsistent experimental setups that lead to increased risk in data repeatability. Diagnosing the known and unknown inconsistencies in the vibration test setup and strategizing solutions to fix the issues are of the utmost concern. Complications in the test setup parameters are artifacts of the uniqueness of the Free-Free test itself. Therefore, a greater understanding of how to achieve reliable and consistent Free-Free fatigue results is crucial for the advancement of aerospace structures and systems.
Experimental Characterization of Polyurethane Adhesive: Independence of Environmental and Mechanical Aging
Authors: Shaafaey Mamoon , Bahrololoumi Amir , Dargazany Roozbeh 
Published: February 2023

Abstract
Assessment of the durability of elastomers for structural applications has been of much interest among the literary circles for quite some time. All polymeric materials undergo degradation when in contact with aggressive environmental agents like humidity, water, and temperature. This rate of degradation should increase with the growing intensity of the ambient environmental agents involved. On the other hand, during service life, these materials are also subjected to mechanical loading in one way or the other. The rate and extent of degradation can be accessed by scrutinizing the changes in constitutive behavior of material through mechanical and chemical properties. Accelerated thermal, hydrolytic, and hygrothermal aging are among the most common modes of process-related degradation, leading generally to chain scission, cross-linking phenomena, and reduced resistance to fracture stress and strain. In this experimental study, our goal is to separate the environmental degradation from mechanical damage. A polyurethane based (PUB) adhesive was aged in thermo-oxidative (0%RH), hydrolytic aging, and hygrothermal (80%RH) aging environments. The damage and decay mechanisms have been used to draw a distinction between environmental degradation and mechanical damage. Material characterization included cyclic tensile tests, gravimetric measurements to observe water-uptake, FTIR and scanning electron microscopy (SEM) tests on as-received and aged samples. Aging was conducted at three different temperatures (60°C, 80°C and 95°C) and four different exposure durations (1, 10, 30, and 90 days). This work confirms that environmental degradation is separable from mechanical damage. Data collected during gravimetric measurements indicate that during aging in desalinated water, water uptake increases linearly with the square root of the aging duration, which agrees with Fick’s second law. Increasing water uptake is proportional to decreasing tensile strength and toughness of the material. The total mechanical and environmental damage is a synergized effect of all exposure conditions and parameters involved i.e. aging time, temperature, oxygen, water, and humidity. The chemistry and mechanics of the polymer degradation were found to be in good agreement with each other.
Effect of Pyrolysis-Front Velocity on the Properties of Biochar Produced With a TLUD Reactor
Authors: Nasef Ziad , Gomez Hector , Mondal Sourov Kumar , Diaz Gerardo 
Published: February 2023

Abstract
Biochar is produced by pyrolysis process which is the thermal decomposition of organic material, usually at temperatures between 300 and 800°C with little to no oxygen. One technology that falls into the category of low-cost pyrolysis reactor is the Top Lit Up Draft (TLUD). It utilizes a batch process where the biomass is lit at the top. The descending pyrolysis zone eventually reaches the bottom of the fuel, completing the conversion process and resulting in production of biochar. The reactor uses a forced draft of air supplied at the bottom. An experimental approach was used in this paper to study the TLUD configuration for almond shells, where temperature profiles are shown inside the pyrolysis reactor (pyrolyzer). The correlation between primary airflow and pyrolysis front downward velocity was studied, where the effect of insulation was experimentally analyzed. The volatile gases produced were combusted using an external burner to reduce air pollution. The contribution of this paper is to correlate uniformity of the final product with ambient temperature and pyrolysis front speed. Experiments were carried out for 5, 10 and 15 Lmin−1 airflows with and without insulation. This paper creates a framework for the addition of a control scheme that may ensure uniform quality of biochar produced in TLUD configuration.
Characterizing Swimming Locomotions of an Asymmetrical Soft Millirobot in a Rotating Magnetic Field
Authors: Bagley Jake T. , Quasebarth Graham B. , Kim Dal Hyung 
Published: February 2023

Abstract
Millimeter-scale robots have many applications in bioengineering fields due to their ability to be actuated remotely. Certain forms of locomotion allow them to achieve high swim speeds while maintaining controllability. The corkscrew locomotions have been achieved in previous soft robot studies, but their swim speeds were much lower than those exhibited by soft robots of different locomotions. In this paper, a corkscrew swimming motion with a high swim speed was achieved with a 3D rotating magnetic field by designing an asymmetrical soft robot made of flexible polymer embedded with magnetic particles and magnetized at a specific orientation. While this robot exhibited a rolling and transient locomotion at magnetic field frequencies lower than 40 Hz, at frequencies above 40 Hz, the robot exhibited corkscrew swimming locomotion. The swimming speed peaked at a velocity of about 30 mm/s at a magnetic field frequency of 49 Hz. Beyond this frequency, the swim speed of the soft robot decreased because the rotational frequency of the robot could not match the frequency of the actuating magnetic field.
Improvement of the Sensitivity and Selectivity of Gas Molecules of Graphene-Base Gas Sensor With Carbon Nanotubes Under the Application of Strain
Authors: Hirose Yuto , Qiao Xiangyu , Fu Wangyang , Suzuki Ken , Miura Hideo 
Published: February 2023

Abstract
A biochemical sensor using graphene nanoribbons as a sensing element was developed for a new generation highly sensitive and compact multi-gas sensor of human’s breath for the early detection of various diseases. Even though the resistance changes of graphene appeared by adsorption of various gases, it was impossible to identify the gas molecules individually when plural kinds of gas molecules adsorbed on graphene at the same time. No selectivity was confirmed so far. In this study, to improve the sensitivity and selectivity of graphene-base gas sensor, carbon nanotubes (CNTs) were directly synthesized on graphene for increasing the area of the molecular adsorption surface. The synthesis of graphene was carried out inside a low-pressure chemical vapor deposition chamber on a copper catalyst substrate with very high purity. The grown graphene was then, transferred onto a Si/SiO2 substrate. No damage was confirmed in graphene during this transfer process. A thermochemical vapor deposition method was also applied to the production of a CNT layer directly on the GNR sensor elements. The stable ohmic contact between the synthesized CNTs and the base graphene layer was confirmed. The graphene-base gas sensor with a CNT layer showed drastic increase in the sensitivity of gas molecules comparing with a conventional single graphene-base sensor.
Numerical Study on Convective Heat Transfer Performance in Helix Lattice Sandwich Panel
Authors: Li Shulei , Zhang Shibo , Xie Gongnan , Yan Hongbin 
Published: February 2023

Abstract
Sandwich structures have been widely used as thermal and load-bearing materials in astronautic and aeronautic applications. owing to their advantages of high specific strength and stiffness. Among them, the X-type lattice cored sandwich panel has a superior thermal performance, with a larger pressure drop. In order to solve the disadvantage of higher pressure drop of the X-type lattice, this paper propose a new structure of helix lattice sandwich panel by modifying the structure of the X-type lattice at a similar porosity level. Forced convection of air in the helix lattice sandwich panel was numerically studied based on the validated model in available literature. The flow and heat transfer characteristics between the helix lattice and X-type lattice were compared. Results reveal that the fluid flow pattern of the helix lattice and the X-type lattice have similarities and differences. The similarity is that both of them cause a spiral type of flow and two same type of secondary flow, the difference is that compared with X-type lattice, the smaller blockage of flow area by the ligaments of the helix lattice leads to a large smooth mainstream. Besides, the overall Nusselt number of the helix lattice is slightly lower than that of X-type one with an average value of 6.69% at a certain Reynolds number, the same material thermal conductivity and similar porosity level. Although the flow pattern in the helix lattice is similar to that in X-type lattice, the smooth mainstream in the helix lattice inevitably limited the flow mixing which lead to a lower area-averaged Nusslet number on both the substrates and the ligaments relative to X-type one. However, in terms of pressure drop, the helix lattice is significantly lower than the X-type lattice due to smaller flow area blockage and smooth ligament structure, which is reduced by nearly half. The helix lattice core sandwich panel can maintain a high level heat transfer performance with little loss of pressure drop. For a given pumping power, the helix lattice outperforms X-type lattice by up to 6.65%. Furthermore, as the pumping power increases, the heat transfer performance of the helix lattice will be better than X-type lattice. Therefore, it can be considered that the helix lattice core sandwich panel solves the disadvantage of relatively high pressure drop in the X-type lattice, greatly reduced the pressure drop and the required pumping power with less heat transfer performance loss. The helix lattice core sandwich panel has a superior comprehensive heat transfer performance than X-type one.
Predicting the Hounsfield Unit (HU) of Aluminum Alloy AA2011 From the Weight Fractions of its Alloying Elements: An X-Ray Computed Tomography Study
Authors: Baydoun Ahmad M. R. , Hamade Ramsey F. 
Published: February 2023

Abstract
X-ray computed tomography scans are being increasingly employed as a non-destructive testing method for the detection of internal defects and material identification. However, mean Hounsfield Unit (HU) measurements for many metals and alloys are unreported in the literature due to the high HU values of metals and their alloys and also due to the wide range of possible combinations of X-ray scanning parameters. For this reason, developing a method that can accurately predict the mean Hounsfield unit value of a material given its elemental composition and mean Hounsfield measurements of its constituent elements is valuable and can help fill the gap for under-reported materials.
In this study, first, the mean Hounsfield values for AA2011 are predicted using two methods based on the mixture model. Second, the effect of the X-ray scanning parameters on the predictive accuracy of the mean Hounsfield Unit value for AA2011 is studied. To this end, X-ray CT scans are performed at three X-ray tube current levels (50, 100, and 200 mAs) and two tube voltage levels (120 and 140kVp). Also considered is the effect of scan window size (field of scan view) as represented by voxel size where three sizes (0.00287, 0.0176, and 0.0452 mm3) are utilized. The effect of sample thickness is assessed via three thickness levels (1.5, 3, and 6 mm). The findings show that both methods show good predictive ability with the second method showing greater accuracy.
An Experimental Investigation of the Mechanical Behavior of 3D Printed Structures As a Function of Manufacturing Process Decisions
Authors: Hamel Josh , Kamla Logan 
Published: February 2023

Abstract
When using additive manufacturing (AM) systems to fabricate functional parts built up in a layer-by-layer fashion, designers are required to make numerous decisions with respect to manufacturing processes parameters that can have significant impacts on how the resulting parts will perform under loading. One such parameter of interest is the orientation of the part within the build volume of the AM system utilized during fabrication. This parameter is important because the choice of build angle will directly impact how applied loads are transmitted to the bonded layers of the finished part. This paper presents the results of an experimental study specifically designed to explore this important factor and its effect on several key mechanical properties, including bending stiffness, ultimate strength, and toughness. This study consisted of printing and testing a large set of simple functional parts using a wide variety of build angle geometries, in addition to also considering other common process parameters focused on by previous studies. This study considered parts produced using two different AM technologies (material extrusion and vat polymerization), and multiple printing materials, in order to generate a dataset that can be used to inform the modeling and design of functional parts to be manufactured via various AM systems. The results produced show general agreement with previous similar studies, and the effects of build orientation present in the dataset generated clearly show the need for designers to consider this important parameter carefully when designing parts for AM applications. The results of this study also demonstrate the need for continued research on this critical topic to the field of AM in general.
Inhomogeneous Microstructure due to Non-Uniform Solidification Rate in NiTi Triply Periodic Minimal Surface (TPMS) Structures Fabricated via Laser Powder Bed Fusion
Authors: Hussain Shahadat , Alagha Ali N. , Zaki Wael 
Published: February 2023

Abstract
In recent times, interest in the fabrication of porous NiTi structures have grown significantly. Porous structures have remarkable potential to be used in the areas of tissue engineering, impact absorption, and fluid permeability. However, fabrication of NiTi structures poses challenges such as poor machinability, high work hardening, and inherent springback effects, which render them difficult to tackle through conventional manufacturing routes. Additive manufacturing (AM) can alleviate the aforementioned issues associated with NiTi shape memory alloys (SMAs). In addition, this technology can be employed for producing metallic scaffolds and porous structures of complex architectural details. Recently, a class of minimal surface topologies, known as triply periodic minimal surface (TPMS) structures has emerged as an attractive configuration for building architected constructs. Very little work can be found in the literature addressing the fabrication of NiTi TPMS structures and investigating their behaviors. The complex geometries of these structures may influence the dynamics of the melt pool in beam-based AM processes as well as the solidification rate within different regions of a product, thereby affecting the microstructures of fabricated parts. An inhomogeneity in microstructures of fabricated parts was observed, which motivated a detailed examination of these structures. The novelty of the present work lies in studying the influence of geometries of NiTi TPMS lattices along with laser process parameters.
Modeling Thermal Behavior and Residual Stress for Layer-by-Layer Rotated Scan Direction in Laser Powder Bed Fusion Process
Authors: Roney Md. Saidur Rahman , Ahsan Nazmul , Sezer Hayri , Tang Joseph , Kaul Sudhir , Ahmed Hossain 
Published: February 2023

Abstract
Laser powder bed fusion (LPBF) is an Additive Manufacturing (AM) process that uses a laser beam to solidify powder particles following a predefined pattern on a powder bed to build a part layer-by-layer as per a CAD model. In LPBF, the moving heat source and the rapid solidification cause nonuniform variations in temperature along the build part. This transient and moving heating and cooling process causes uneven expansion and shrinkage of the part that leads to the development of residual stresses in the part. The residual stresses depend on the thermal history of the part and may eventually lead to part distortion, crack initiation, warpage, etc. The present study represents the effect of altering the scan pattern layer-by-layer on the residual stress. Furthermore, a novel alternating double pass spiral scan pattern is introduced and compared with alternating island zigzag, alternating zigzag, regular zigzag, and spiral out-center patterns on the basis of thermal distribution and residual stress. Numerical approach is used to solve the governing equations. It is observed that residual stress greatly depends on thermal distribution. The variation in inherent residual stress is found to be lower for alternating zigzag pattern than regular zigzag pattern due to more even thermal distribution. Furthermore, the novel pattern also effectively distributes the heat which contributes to the reduction of inherent residual stress from the first layer. On the other hand, it is found that the alternating island zigzag scan pattern increases island temperature that can prevent rapid solidification. Overall, the findings of this study can be helpful in understanding the effects of altering scan directions layer-by-layer and in identifying a scan strategy that can enhance the usability of the powder bed fusion additive manufacturing technology.
Vision Based Safe Navigation of UAV for Overhead Line Inspection Enabled by Virtual Safety Bubble
Authors: Salim Rufaidah , Rezk Mahmoud , Anzil Mohammed Minhas , AlJasmi Nawal , Shukla Amit 
Published: February 2023

Abstract
Energy transmission systems have expanded significantly, given the increase in demand for power generation. This increase in size has led to the need of a robust inspection method. Overhead Line (OHL) systems consist of many critical components such as insulators, poles, and power lines, which need to be inspected regularly. With recent advancements, drones equipped with multiple sensors are flown, either manually or autonomously, for inspection. This paper proposes autonomous vision-based navigation of the drone over OHL. The navigation is achieved through the feedback from the camera onboard the drone. A deep learning-based model is developed for the detection of the various OHL components, which are then utilized to design the path for the drone to navigate. Furthermore, a virtual safety bubble (VSB) is developed around the drone upon the detection of the components. This VSB is part of local autonomy of the drone and ensures that a constant safe distance is always maintained from the components. This approach can help reduce the overall inspection time of OHL with less cognitive load on the operator. It also ensures the safety of the OHL installations and drone. Although the paper focuses mainly on running the experiments in a simulation environment, this could be imitated in real-life situations.
Approach for Kano-IPA Analysis of Product Attributes From Online Reviews and Product Maintenance Records
Authors: Cheng Aoxiang , Shen Mengyuan , Bi Youyi 
Published: February 2023

Abstract
Kano analysis and importance-performance analysis (IPA) are widely used for needs analysis, product positioning, and strategic planning in product design. Previous research uses customer surveys and online reviews as the main data sources. However, these data carry inevitable subjective bias. In contrast, product maintenance records provide objective information on product quality issues and failure patterns, which can be cross-validated with customers’ personal experience from online reviews. In this paper, we propose a systematic approach for conducting Kano-IPA analysis from online reviews and product maintenance records synthetically. An attribute-keyword dictionary is first established using keyword extraction and clustering methods from online reviews and maintenance records. After that, semantic groups including product attributes and associated descriptions are extracted by dependency parsing analysis. The sentiment scores of identified attributes are calculated by a self-supervised representation learning approach (Sentiment Knowledge Enhanced Pre-training, SKEP) from the built semantic groups. Sentiment scores and occurrence frequencies of attributes in online reviews are utilized for Kano analysis. The importance of product attributes in IPA is estimated from the impact of sentiments of each product attribute on product ratings, while the performance is estimated from the sentiment scores of online reviews or the quality statistics from maintenance records. A case study of passenger vehicles shows that integrated data can provide more comprehensive results and richer insights. The proposed approach enables automatic data processing and can support companies to make efficient design decisions with broader perspectives from multi-source data.