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1
Khodaei, B., F. Samadzadegan, F. Dadras Javan e H. Hasani. "3D SURFACE GENERATION FROM AERIAL THERMAL IMAGERY". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-1-W5 (11 dicembre 2015): 401–5. http://dx.doi.org/10.5194/isprsarchives-xl-1-w5-401-2015.
Abstract (sommario):
Aerial thermal imagery has been recently applied to quantitative analysis of several scenes. For the mapping purpose based on aerial thermal imagery, high accuracy photogrammetric process is necessary. However, due to low geometric resolution and low contrast of thermal imaging sensors, there are some challenges in precise 3D measurement of objects. In this paper the potential of thermal video in 3D surface generation is evaluated. In the pre-processing step, thermal camera is geometrically calibrated using a calibration grid based on emissivity differences between the background and the targets. Then, Digital Surface Model (DSM) generation from thermal video imagery is performed in four steps. Initially, frames are extracted from video, then tie points are generated by Scale-Invariant Feature Transform (SIFT) algorithm. Bundle adjustment is then applied and the camera position and orientation parameters are determined. Finally, multi-resolution dense image matching algorithm is used to create 3D point cloud of the scene. Potential of the proposed method is evaluated based on thermal imaging cover an industrial area. The thermal camera has 640×480 Uncooled Focal Plane Array (UFPA) sensor, equipped with a 25 mm lens which mounted in the Unmanned Aerial Vehicle (UAV). The obtained results show the comparable accuracy of 3D model generated based on thermal images with respect to DSM generated from visible images, however thermal based DSM is somehow smoother with lower level of texture. Comparing the generated DSM with the 9 measured GCPs in the area shows the Root Mean Square Error (RMSE) value is smaller than 5 decimetres in both X and Y directions and 1.6 meters for the Z direction.
2
Li, Ya Yun, Jongwon Kim, Yunquan Sun e Yanhua Yang. "Thermomechanical Analytical 3D Thermal/Stress Estimation Sidewall Grinding Model". Journal of Manufacturing Science and Engineering 121, n. 3 (1 agosto 1999): 378–84. http://dx.doi.org/10.1115/1.2832692.
Abstract (sommario):
A general three-dimensional thermal/stress grinding model, based on thermal and elastic/plastic classical analytical solutions, has been developed in this paper. The thermal model can predict the temperature distribution of surface and cylindrical external/internal creep-feed or conventional grinding for vertical or inclined sidewall surface grinding. This paper deals with a grinding burn problem that is widespread in the aerospace and automotive industries. The thermal model is compared with sidewall surface grinding experiments. The comparison of the temperature distribution results is expected. The general stress model has been developed, which combines both spherical and cylindrical coordinates. In addition, the 3D thermal/stress model is compared with four cases of external cylindrical grinding experiments. The residual stresses agree reasonably.
3
Chen, Yongjun, e Tubing Yin. "Digital Fracture Surface Morphology and Statistical Characteristics of Granite Brazilian Tests after Non-Steady-State Thermal Disturbance". Mathematics 12, n. 5 (24 febbraio 2024): 670. http://dx.doi.org/10.3390/math12050670.
Abstract (sommario):
With the widespread advent of digital technologies, traditional perspectives in rock mechanics research are poised for further expansion. This paper presents a Brazilian test conducted on granite after non-steady-state thermal disturbance at 25 °C, 200 °C, 400 °C, and 600 °C, with detailed documentation of the damage process and failure response using an acoustic emission (AE) apparatus and a digital image correlation (DIC) system. Subsequently, utilizing point cloud data captured by a three-dimensional (3D) laser scanning system, a digital reconstruction of the failed specimen’s fracture surface was accomplished. The 3D fractal characteristics and roughness response of the digitized fracture surface were studied using the box-counting method and least squares approach. Furthermore, texture information of the digitized fracture surface was calculated using the Gray Level Co-occurrence Matrix (GLCM), and statistical characteristics describing the elevation distribution were analyzed. The results elucidate the influence of thermal disturbance temperature on the mechanical parameters of the specimen, acoustic emission behavior, surface strain field evolution, and digital fracture morphology characteristics. The findings indicate a non-linear degradation effect of temperature on the specimen’s tensile strength, with a reduction reaching 80.95% at 600 °C, where acoustic emission activity also peaked. The rising thermal disturbance temperature inhibited the crack initiation load at the specimen’s center but expanded the high-strain concentration areas and the growth rate of horizontal displacement. Additionally, varying degrees of linear or non-linear relationships were discovered between thermal disturbance temperature and the 3D fractal dimension of the fracture surface, average roughness (Ra), peak roughness (Rz), and root mean square roughness (Rq), confirming the potential of Rsm in predicting the 3D fractal dimension of Brazilian test fracture surfaces. The study of the GLCM of the digitized 3D fracture surface demonstrated a high dependency of its four second-order statistical measures on thermal disturbance temperature. Finally, the statistical parameters of the fracture surface’s elevation values showed a significant non-linear relationship with thermal disturbance temperature, with a critical temperature point likely existing between 400 and 600 °C that could precipitate a sudden change in the fracture surface’s elevation characteristics.
4
Gutierrez, Evelyn, Benjamín Castañeda, Sylvie Treuillet e Ivan Hernandez. "Multimodal and Multiview Wound Monitoring with Mobile Devices". Photonics 8, n. 10 (2 ottobre 2021): 424. http://dx.doi.org/10.3390/photonics8100424.
Abstract (sommario):
Along with geometric and color indicators, thermography is another valuable source of information for wound monitoring. The interaction of geometry with thermography can provide predictive indicators of wound evolution; however, existing processes are focused on the use of high-cost devices with a static configuration, which restricts the scanning of large surfaces. In this study, we propose the use of commercial devices, such as mobile devices and portable thermography, to integrate information from different wavelengths onto the surface of a 3D model. A handheld acquisition is proposed in which color images are used to create a 3D model by using Structure from Motion (SfM), and thermography is incorporated into the 3D surface through a pose estimation refinement based on optimizing the temperature correlation between multiple views. Thermal and color 3D models were successfully created for six patients with multiple views from a low-cost commercial device. The results show the successful application of the proposed methodology where thermal mapping on 3D models is not limited in the scanning area and can provide consistent information between multiple thermal camera views. Further work will focus on studying the quantitative metrics obtained by the multi-view 3D models created with the proposed methodology.
5
Grechi, Guglielmo, Matteo Fiorucci, Gian Marco Marmoni e Salvatore Martino. "3D Thermal Monitoring of Jointed Rock Masses through Infrared Thermography and Photogrammetry". Remote Sensing 13, n. 5 (4 marzo 2021): 957. http://dx.doi.org/10.3390/rs13050957.
Abstract (sommario):
The study of strain effects in thermally-forced rock masses has gathered growing interest from engineering geology researchers in the last decade. In this framework, digital photogrammetry and infrared thermography have become two of the most exploited remote surveying techniques in engineering geology applications because they can provide useful information concerning geomechanical and thermal conditions of these complex natural systems where the mechanical role of joints cannot be neglected. In this paper, a methodology is proposed for generating point clouds of rock masses prone to failure, combining the high geometric accuracy of RGB optical images and the thermal information derived by infrared thermography surveys. Multiple 3D thermal point clouds and a high-resolution RGB point cloud were separately generated and co-registered by acquiring thermograms at different times of the day and in different seasons using commercial software for Structure from Motion and point cloud analysis. Temperature attributes of thermal point clouds were merged with the reference high-resolution optical point cloud to obtain a composite 3D model storing accurate geometric information and multitemporal surface temperature distributions. The quality of merged point clouds was evaluated by comparing temperature distributions derived by 2D thermograms and 3D thermal models, with a view to estimating their accuracy in describing surface thermal fields. Moreover, a preliminary attempt was made to test the feasibility of this approach in investigating the thermal behavior of complex natural systems such as jointed rock masses by analyzing the spatial distribution and temporal evolution of surface temperature ranges under different climatic conditions. The obtained results show that despite the low resolution of the IR sensor, the geometric accuracy and the correspondence between 2D and 3D temperature measurements are high enough to consider 3D thermal point clouds suitable to describe surface temperature distributions and adequate for monitoring purposes of jointed rock mass.
6
Paraschiv, Alexandru, Gheorghe Matache, Cristian Puscasu e Raluca Condruz. "Non-Contact Roughness Investigation of Ball-Cratered Molybdenum Thermal Spray Coatings". Applied Mechanics and Materials 859 (dicembre 2016): 9–14. http://dx.doi.org/10.4028/www.scientific.net/amm.859.9.
Abstract (sommario):
The effects of micro-abrasion wear on the surface roughness of molybdenum coatings deposited by electric arc thermal spray on steel support were investigated. The 2D surface roughness was measured and correlated with the experimental results of the micro-abrasion tests. Different worn surfaces which correspond to running-in and steady stage of wear were investigated in terms of the microstructure, 3D image and 2D surface roughness. The micro-abrasion tests were made in the presence of a SiC abrasive slurry for test durations between 200 – 1600 s and the worn surfaces were evaluated by scanning electron microscopy and stereomicroscopy.
7
Han, Pu, Sihan Zhang, Zhong Yang, M. Faisal Riyad, Dan O. Popa e Keng Hsu. "In-Process Orbiting Laser-Assisted Technique for the Surface Finish in Material Extrusion-Based 3D Printing". Polymers 15, n. 9 (8 maggio 2023): 2221. http://dx.doi.org/10.3390/polym15092221.
Abstract (sommario):
Material extrusion-based polymer 3D printing, one of the most commonly used additive manufacturing processes for thermoplastics and composites, has drawn extensive attention due to its capability and cost effectiveness. However, the low surface finish quality of the printed parts remains a drawback due to the nature of stacking successive layers along one direction and the nature of rastering of the extruded tracks of material. In this work, an in-process thermal radiation-assisted, surface reflow method is demonstrated that significantly improves the surface finish of the sidewalls of printed parts. It is observed that the surface finish of the printed part is drastically improved for both flat and curved surfaces. The effect of surface reflow on roughness reduction was characterized using optical profilometry and scanning electron microscopy (SEM), while the local heated spot temperature was quantified using a thermal camera.
8
Dadras Javan, F., e M. Savadkouhi. "THERMAL 3D MODELS ENHANCEMENT BASED ON INTEGRATION WITH VISIBLE IMAGERY". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W18 (18 ottobre 2019): 263–69. http://dx.doi.org/10.5194/isprs-archives-xlii-4-w18-263-2019.
Abstract (sommario):
Abstract. In the last few years, Unmanned Aerial Vehicles (UAVs) are being frequently used to acquire high resolution photogrammetric images and consequently producing Digital Surface Models (DSMs) and orthophotos in a photogrammetric procedure for topography and surface processing applications. Thermal imaging sensors are mostly used for interpretation and monitoring purposes because of lower geometric resolution. But yet, thermal mapping is getting more important in civil applications, as thermal sensors can be used in condition that visible sensors cannot, such as foggy weather and night times which is not possible for visible cameras. But, low geometric quality and resolution of thermal images is a main drawback that 3D thermal modelling are encountered with. This study aims to offer a solution for to fixing mentioned problem and generating a thermal 3D model with higher spatial resolution based on thermal and visible point clouds integration. This integration leads to generate a more accurate thermal point cloud and DEM with more density and resolution which is appropriate for 3D thermal modelling. The main steps of this study are: generating thermal and RGB point clouds separately, registration of them in two course and fine level and finally adding thermal information to RGB high resolution point cloud by interpolation concept. Experimental results are presented in a mesh that has more faces (With a factor of 23) which leads to a higher resolution textured mesh with thermal information.
9
Matringe, Caroline, Elsa Thune, René Guinebretière e David Babonneau. "Self-ordering on vicinal surfaces studied by 3D GISAXS measurements". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 agosto 2014): C879. http://dx.doi.org/10.1107/s2053273314091207.
Abstract (sommario):
Nanostructured systems made of islands deposited onto oxide surfaces have both fundamental and technological interests and are used in the field of electronic, linear or non-linear optic, and optoelectronic. The final properties of these systems depend on the shape and the size of nanoparticles and also on their organization. On this general framework, we aim at producing self-organized nanostructures using vicinal surfaces [1],[2]. Vicinal surfaces are obtained by cutting a single crystal with a small deviation of the surface normal with respect to a crystallographic plane leading to a surface with terraces separated by steps. Suitable templates for the growth of self-organized nanostructures are created thanks to the re-arrangement of the steps during thermal treatment (step bunching). Different types of nanostructured surfaces can be elaborated and used as templates since the substrates exhibit a one-dimensional (1D) or two-dimensional (2D) periodic patterns (fig. 1a). The surface morphology and the periodicity can be tuned with the thermal treatment parameters (i.e. annealing time, temperature and atmosphere) and also with the sample parameters (i.e. miscut and azimuthal angles). Ordered stepped oxide surfaces are characterized ex-situ after each treatment on a laboratory scale by Atomic Force Microscopy (AFM), which provide a direct image of the surface morphology (step height, step curvature, terrace width...) over a small probed area (a few µm2). Quantitative analysis of the surface morphology has been studied by grazing incidence small angle scattering using a specific set-up implemented recently onto the BM02 beamline at ESRF (Grenoble, France). Prior to the SAXS measurements, the samples were strictly oriented according to the primary beam direction using a 3-axis sample holder. 3D reciprocal space maps around the (000) node were then recorded onto a 2D pixel detector through 3600rotation of the samples around the azimuthal angle. Modelling of 2D sections of the (000) reciprocal space node were realized using the FitGISAXS software [3]. Typical experimental and calculated maps are reported fig. 1b and 1c. We demonstrate that the 2D ordered surface is consistent with a rectangular centred periodic lattice decorated by truncated tetrahedrons (see fig. 1d).
10
Dlouhá, Ž., M. Vostřák, J. Duliškovič, I. Zetková e T. Mařík. "Adhesion of selected thermally sprayed coatings on additive manufactured maraging steel". Journal of Physics: Conference Series 2572, n. 1 (1 agosto 2023): 012006. http://dx.doi.org/10.1088/1742-6596/2572/1/012006.
Abstract (sommario):
Abstract Additive manufacturing (AM) technology is increasingly expanding into different types of industries. Still, many potential applications are restricted due to the limited choice of materials used in AM. A suitable solution could be a combination of AM and thermal spraying of functional parts of the surface to achieve superior surface properties. This work aims to study the possibility to prepare the surface with AM technology to direct application of coating by thermal spraying without any additional surface preparation. To verify this possibility, the parameters of the 3D printing technology were adjusted to achieve suitable surface structures for the following thermal spraying. Several variants of modifications with different surface properties were selected. The samples were printed from maraging steel using the DMLS technology. The coatings chosen for testing were WC – CoCr and Stellite 6 sprayed by HVOF and further NiAl and Al2O3-TiO2 sprayed by APS. The adhesion of the coating was tested by an adhesion test performed under the ASTM C633-79 standard. The bonding of the coating on the surface was studied by metallographic analysis. The achieved results indicate that the adhesion of HVOF sprayed WC-CoCr coating on 3D printed surfaces is excellent for most surface modifications. The Stellite 6 exhibits good adhesion on several surface modifications. The APS sprayed coating shows significantly lower adhesion, the NiAl and Al2O3-TiO2 coatings can be successfully sprayed only on selected surface modifications.
11
Cheng, Christine, e Malancha Gupta. "Surface functionalization of 3D-printed plastics via initiated chemical vapor deposition". Beilstein Journal of Nanotechnology 8 (8 agosto 2017): 1629–36. http://dx.doi.org/10.3762/bjnano.8.162.
Abstract (sommario):
3D printing is a useful fabrication technique because it offers design flexibility and rapid prototyping. The ability to functionalize the surfaces of 3D-printed objects allows the bulk properties, such as material strength or printability, to be chosen separately from surface properties, which is critical to expanding the breadth of 3D printing applications. In this work, we studied the ability of the initiated chemical vapor deposition (iCVD) process to coat 3D-printed shapes composed of poly(lactic acid) and acrylonitrile butadiene styrene. The thermally insulating properties of 3D-printed plastics pose a challenge to the iCVD process due to large thermal gradients along the structures during processing. In this study, processing parameters such as the substrate temperature and the filament temperature were systematically varied to understand how these parameters affect the uniformity of the coatings along the 3D-printed objects. The 3D-printed objects were coated with both hydrophobic and hydrophilic polymers. Contact angle goniometry and X-ray photoelectron spectroscopy were used to characterize the functionalized surfaces. Our results can enable the use of iCVD to functionalize 3D-printed materials for a range of applications such as tissue scaffolds and microfluidics.
12
Jo, Wonjin, Do Hyun Kim, Jeong Sim Lee, Heon Ju Lee e Myoung-Woon Moon. "3D printed tactile pattern formation on paper with thermal reflow method". RSC Adv. 4, n. 60 (2014): 31764–70. http://dx.doi.org/10.1039/c4ra02822h.
Abstract (sommario):
The combination of 3D FDM printing method and thermal reflow technique was applied to fabricate tactile patterns for visually impaired people. The size controllable 3D tactile patterns were significantly improved in surface smoothness and adhesion strength on papers.
13
Koo, Jae-Mo, Sungjun Im, Linan Jiang e Kenneth E. Goodson. "Integrated Microchannel Cooling for Three-Dimensional Electronic Circuit Architectures". Journal of Heat Transfer 127, n. 1 (1 gennaio 2005): 49–58. http://dx.doi.org/10.1115/1.1839582.
Abstract (sommario):
The semiconductor community is developing three-dimensional circuits that integrate logic, memory, optoelectronic and radio-frequency devices, and microelectromechanical systems. These three-dimensional (3D) circuits pose important challenges for thermal management due to the increasing heat load per unit surface area. This paper theoretically studies 3D circuit cooling by means of an integrated microchannel network. Predictions are based on thermal models solving one-dimensional conservation equations for boiling convection along microchannels, and are consistent with past data obtained from straight channels. The model is combined within a thermal resistance network to predict temperature distributions in logic and memory. The calculations indicate that a layer of integrated microchannel cooling can remove heat densities up to 135W/cm2 within a 3D architecture with a maximum circuit temperature of 85°C. The cooling strategy described in this paper will enable 3D circuits to include greater numbers of active levels while exposing external surface area for functional signal transmission.
14
Liu, Yi-Hsien, Kong-Kai Kuo e Chung-Wei Cheng. "Femtosecond Laser-Induced Periodic Surface Structures on Different Tilted Metal Surfaces". Nanomaterials 10, n. 12 (17 dicembre 2020): 2540. http://dx.doi.org/10.3390/nano10122540.
Abstract (sommario):
Laser-induced periodic surface structures (LIPSS) are used for the precision surface treatment of 3D components. However, with LIPSS, the non-normal incident angle between the irradiated laser beam and the specimen surface occurs. This study investigated LIPSS on four different metals (SUS 304, Ti, Al, and Cu), processed on a tilted surface by an s-polarized femtosecond fiber laser. A rotated low spatial frequency LIPSS (LSFL) was obtained on SUS 304 and Ti materials by the line scanning process. However, LSFL on Cu and Al materials was still perpendicular to the laser polarization. The reason for the rotated and un-rotated LSFL on tilted metal surfaces was presented. The electron-phonon coupling factor and thermal conductivity properties might induce rotational LSFL on tilted SUS 304 and Ti surfaces. When fabricating LSFL on an inclined plane, a calibration model between the LSFL orientation and inclined plane angle must be established. Hence, the laser polarization direction must be controlled to obtain suitable LSFL characteristics on a 3D surface.
15
Lecomte, V., H. Macher e T. Landes. "COMBINATION OF THERMAL INFRARED IMAGES AND LASERSCANNING DATA FOR 3D THERMAL POINT CLOUD GENERATION ON BUILDINGS AND TREES". International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVIII-2/W1-2022 (8 dicembre 2022): 129–36. http://dx.doi.org/10.5194/isprs-archives-xlviii-2-w1-2022-129-2022.
Abstract (sommario):
Abstract. The thermal infrared study of urban environments is of growing interest. It allows to observe the variations of surface temperatures on objects over time and therefore the microclimate at the scale of a street. To facilitate the analysis of thermal interactions between urban elements, it is necessary to provide a 3D visualization of the thermography of a street. For this purpose, 3D thermal models combining geometric and thermal infrared (TIR) measurements are required. The chosen format for 3D thermal models is a point cloud with a temperature attribute. In our approach, two types of urban components are considered: buildings and trees. The geometric data of each component are acquired with a static laser scanner and the surface temperature is acquired with a thermal handheld camera. For the building, the approach consists in georeferencing TIR images and colorize the point cloud by projection. For trees, the approach consists of the colorization of each laser scan prior to the registration. The spherical panoramic images acquired with the Terrestrial Laser Scanning (TLS) are used as references to automatically georeferenced the TIR and thus to save time. The 3D thermal models obtained highlight the impact of sunlight on buildings and trees. At building scale, this thermal representation also helps to emphasize thermal bridges, as well as the shadow generated by surrounding trees. At tree scale, this representation is useful for monitoring the temporal and spatial variability of trunk’s and leave’s temperatures. Obviously, the thermal models underline the impact of trees on the urban environment.
16
Schmoll, Robert, Sebastian Schramm, Tom Breitenstein e Andreas Kroll. "Method and experimental investigation of surface heat dissipation measurement using 3D thermography". Journal of Sensors and Sensor Systems 11, n. 1 (11 febbraio 2022): 41–49. http://dx.doi.org/10.5194/jsss-11-41-2022.
Abstract (sommario):
Abstract. Three-dimensional thermography describes the fusion of geometry- and temperature-related sensor data. In the resulting 3D thermogram, thermal and spatial information of the measured object is available in one single model. Besides the simplified visualization of measurement results, the question arises how the additional data can be used to get further information. In this work, the Supplement information is used to calculate the surface heat dissipation caused by thermal radiation and natural convection. For this purpose, a 3D thermography system is presented, the calculation of the heat dissipation is described, and the first results for simply shaped measurement objects are presented.
17
Zhao, Xuexiu, Yanwen Luo e Jiang He. "Analysis of the Thermal Environment in Pedestrian Space Using 3D Thermal Imaging". Energies 13, n. 14 (16 luglio 2020): 3674. http://dx.doi.org/10.3390/en13143674.
Abstract (sommario):
Pedestrian space is an important place for people’s outdoor activities. Its thermal environment affects pedestrian walking experience, route selection and physical health. This study presents a 3D thermography-based method to analyze and evaluate the spatial distribution of thermal comfort. The proposed 3D thermal image was generated using 3D city models captured by an unmanned aerial vehicle (UAV) and thermal images gathered by an infrared camera. It can visualize construction elements, but also simply output surface temperatures at selected points. This paper described the process of using 3D thermal images to analyze the built environment, and selected two pedestrian spaces as case study objects. Their thermal images and mean radiant temperatures (MRT) were obtained from field measurement data collected by a drone and infrared camera. The following findings were obtained: (a) the MRT difference in the pedestrian space between sunlit and shaded areas was more than 3 °C; (b) the MRT values at the measurement points near vegetation were lower; (c) when the ratio of street height to width (H/W) was larger, the MRT values at all measurement points varied slightly. These findings can be used for the designers to evaluate and improve the thermal environment in pedestrian space.
18
Tsai, H. Y., e C. W. Kuo. "Thermal Stress and Failure Location Analysis for Through Silicon via in 3D Integration". Journal of Mechanics 32, n. 1 (7 agosto 2015): 47–53. http://dx.doi.org/10.1017/jmech.2015.52.
Abstract (sommario):
AbstractThrough silicon via (TSV) is the critical structure for three dimensional (3D) integration, which provides vertical interconnection between stacking dies. In TSV structure, large coefficient differences of thermal expansion exist between silicon substrate, dielectric material, and filled metal. Due to the large thermal mismatch, the high thermal stress occurring at the interface of different materials would result in delamination. Therefore, thermal-mechanical reliability is a key issue for 3D integration. In this study, we investigated the thermal-mechanical stress distribution of TSV under the condition of the accelerated thermal cycling loading by finite element analysis based on a 3D model of TSV structure. Due to the thermal expansion, that the TSV structure squeezed the surface area between TSVs at a high temperature resulted in compressive stresses at the surface area between TSVs. Therefore, a proper distance between the stress-sensitive device and the TSV should be kept. The stress analysis shows that the maximum thermal stress occurs in the outside region of TSV interface and in the annular region of TSV at a high temperature and at a low temperature, respectively. This study helps to obtain a clear thermal stress distribution of TSV and possible failure regions can be determined.
19
Hanemann, Thomas, Alexander Klein, Siegfried Baumgärtner, Judith Jung, David Wilhelm e Steffen Antusch. "Material Extrusion 3D Printing of PEEK-Based Composites". Polymers 15, n. 16 (15 agosto 2023): 3412. http://dx.doi.org/10.3390/polym15163412.
Abstract (sommario):
High-performance thermoplastics like polyetheretherketone (PEEK), with their outstanding thermal stability, mechanical properties and chemical stability, have great potential for various structural applications. Combining with additive manufacturing methods extends further PEEK usage, e.g., as a mold insert material in polymer melt processing like injection molding. Mold inserts must possess a certain mechanical stability, a low surface roughness as well as a good thermal conductivity for the temperature control during the molding process. With this in mind, the commercially available high-performance thermoplastic PEEK was doped with small amounts of carbon nanotubes (CNT, 6 wt%) and copper particles (10 wt%) targeting enhanced thermomechanical properties and a higher thermal conductivity. The composites were realized by a commercial combined compounder and filament maker for the usage in a material extrusion (MEX)-based 3D-printer following the fused filament fabrication (FFF) principle. Commercial filaments made from PEEK and carbon fiber reinforced PEEK were used as reference systems. The impact of the filler and the MEX printing conditions like printing temperature, printing speed and infill orientation on the PEEK properties were characterized comprehensively by tensile testing, fracture imaging and surface roughness measurements. In addition, the thermal conductivity was determined by the laser-flash method in combination with differential scanning calorimetry and Archimedes density measurement. The addition of fillers did not alter the measured tensile strength in comparison to pure PEEK significantly. The fracture images showed a good printing quality without the MEX-typical voids between and within the deposited layers. Higher printing temperatures caused a reduction of the surface roughness and, in some cases, an enhanced ductile behavior. The thermal conductivity could be increased by the addition of the CNTs. Following the given results, the most critical process step is the compounding procedure, because for a reliable process–parameter–property relationship, a homogeneous particle distribution in the polymer matrix yielding a reliable filament quality is essential.
20
Kuroda, Kensuke, Shinji Nakamoto, Ryoichi Ichino, Masazumi Okido e Robert M. Pilliar. "Hydroxyapatite Coatings on a 3D Porous Surface Using Thermal Substrate Method". MATERIALS TRANSACTIONS 46, n. 7 (2005): 1633–35. http://dx.doi.org/10.2320/matertrans.46.1633.
21
Hegde, Pradeep, David Whalley e Vadim V. Silberschmidt. "3D Study of Thermal Stresses in Lead-Free Surface Mount Devices". Journal of Thermal Stresses 31, n. 11 (19 settembre 2008): 1039–55. http://dx.doi.org/10.1080/01495730802250763.
22
Kim, Seok, Sang-Hoon Nam, Seokho Kim, Young Tae Cho e Nicholas X. Fang. "Low Heat Capacity 3D Hollow Microarchitected Reactors for Thermal and Fluid Applications". Energies 15, n. 11 (1 giugno 2022): 4073. http://dx.doi.org/10.3390/en15114073.
Abstract (sommario):
Lightweight reactor materials that simultaneously possess low heat capacity and large surface area are desirable for various applications such as catalytic supports, heat exchangers, and biological scaffolds. However, they are challenging to satisfy this criterion originating from their structural property in most porous cellular solids. Microlattices have great potential to resolve this issue in directing transport phenomena because of their hierarchically ordered design and controllable geometrical features such as porosity, specific surface, and tortuosity. In this study, we report hollow ceramic microlattices comprising a 10 μm thick hollow nickel oxide beam in an octet-truss architecture with low heat capacity and high specific surface area. Our microarchitected reactors exhibited a low heat capacity for a rapid thermal response with a small Biot number (Bi << 1) and large intertwined surface area for homogeneous flow mixing and chemical reactions, which made them ideal candidates for various energy applications. The hollow ceramic microlattice was fabricated by digital light three-dimensional (3D) printing, composite electroless plating, polymer removal, and subsequent thermal annealing. The transient thermal response and fluidic properties of the 3D-printed microstructures were experimentally investigated using a small-scale thermal and fluid test system, and analytically interpreted using simplified models. Our findings indicate that hollow microarchitected reactors provide a promising platform for developing multifunctional materials for thermal and fluid applications.
23
Gstoehl, D., e J. R. Thome. "Film Condensation of R-134a on Tube Arrays With Plain and Enhanced Surfaces: Part I—Experimental Heat Transfer Coefficients". Journal of Heat Transfer 128, n. 1 (12 luglio 2005): 21–32. http://dx.doi.org/10.1115/1.2130400.
Abstract (sommario):
The aim of the present investigation was to study the effect of condensate inundation on the thermal performance of a vertical array of horizontal tubes with plain and enhanced surfaces. Refrigerant R-134a was condensed at a saturation temperature of 304K on tube arrays with up to ten tubes at pitches of 25.5,28.6,and44.5mm. Notably, local condensing heat transfer coefficients were measured at the midpoint of each tube, as opposed to mean values. Four commercially available copper tubes with a nominal diameter of 19.05mm(0.75in.) were tested: a plain tube, a 26fpi∕1024fpm low finned tube, and two tubes, with three-dimensional (3D) enhanced surface structures. At low liquid inundation rates, the tubes with 3D enhanced surface structures significantly outperformed the low finned tube. Increasing liquid inundation deteriorated the thermal performance of the 3D enhanced tubes, whereas it had nearly no affect on the low finned tube, resulting in a higher heat transfer coefficients for the low finned tube at high liquid film Reynolds numbers. All the tests were performed with minimal vapor shear.
24
Li, Xiaoyan, Georg Haberfehlner, Ulrich Hohenester, Odile Stéphan, Gerald Kothleitner e Mathieu Kociak. "Three-dimensional vectorial imaging of surface phonon polaritons". Science 371, n. 6536 (25 marzo 2021): 1364–67. http://dx.doi.org/10.1126/science.abg0330.
Abstract (sommario):
Surface phonon polaritons (SPhPs) are coupled photon-phonon excitations that emerge at the surfaces of nanostructured materials. Although they strongly influence the optical and thermal behavior of nanomaterials, no technique has been able to reveal the complete three-dimensional (3D) vectorial picture of their electromagnetic density of states. Using a highly monochromated electron beam in a scanning transmission electron microscope, we could visualize varying SPhP signatures from nanoscale MgO cubes as a function of the beam position, energy loss, and tilt angle. The SPhPs’ response was described in terms of eigenmodes and used to tomographically reconstruct the phononic surface electromagnetic fields of the object. Such 3D information promises insights in nanoscale physical phenomena and is invaluable to the design and optimization of nanostructures for fascinating new uses.
25
Jiang, Weiwei, Chaofan Wang, Zhanna Sarsenbayeva, Andrew Irlitti, Jing Wei, Jarrod Knibbe, Tilman Dingler, Jorge Goncalves e Vassilis Kostakos. "InfoPrint". Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies 7, n. 3 (27 settembre 2023): 1–29. http://dx.doi.org/10.1145/3610933.
Abstract (sommario):
We present a fully-printable method to embed interactive information inside 3D printed objects. The information is invisible to the human eye and can be read using thermal imaging after temperature transfer through interaction with the objects. Prior methods either modify the surface appearance, require customized devices or not commonly used materials, or embed components that are not fully 3D printable. Such limitations restrict the design space for 3D prints, or cannot be readily applied to the already deployed 3D printing setups. In this paper, we present an information embedding technique using low-cost off-the-shelf dual extruder FDM (Fused Deposition Modeling) 3D printers, common materials (e.g., generic PLA), and a mobile thermal device (e.g., a thermal smartphone), by leveraging the thermal properties of common 3D print materials. In addition, we show our method can also be generalized to conventional near-infrared imaging scenarios. We evaluate our technique against multiple design and fabrication parameters and propose a design guideline for different use cases. Finally, we demonstrate various everyday applications enabled by our method, such as interactive thermal displays, user-activated augmented reality, automating thermal triggered events, and hidden tokens for social activities.
26
Bicelli, Antonio Renato, Pedro Cantor, Mário Rui Arruda, Carlos Tiago, Ellon Bernardes de Assis e Fernando Branco. "Numerical Assessment of Standard Firebrand Accumulation Curve When Transferring Temperature to Contact Surfaces". Applied Sciences 13, n. 17 (26 agosto 2023): 9657. http://dx.doi.org/10.3390/app13179657.
Abstract (sommario):
This work presents research concerning the numerical assessment of two previously measured temperatures due to firebrand accumulation on surfaces, which was determined in former thermal experimental campaigns. A 3D numerical model using thermal transient non-linear analysis is used to validate the thermal outputs of these two previous experimental campaigns, and therefore, corroborating the previous temperature vs. time curves created with a prescribed flux in the firebrand accumulation area. The firebrand thermal heat transfer to the plane surface is simulated using convection and radiation film conditions, in which a 3D non-linear, time-dependent finite element simulation is used. Then, the previous proposed standard firebrand accumulation curve, ISO 834, and external fire curve are numerically compared with the results from previous firebrand accumulation curves in a wood corner wall. Finally, the merit assessment of the proposed standard firebrand accumulation curve shows a visible improvement, which has low values and is in accordance with the experimental results in the temperature field distribution of firebrand accumulation onto a contact surface. It is fair to argue that it constitutes a point to search for an efficient design for structures at elevated temperatures due to firebrand accumulation.
27
Ayyakkannu, Ramesh, Sakthi Chandramurthy, Ramasamy Veeramalai e Pradeep Madhesan. "3D computational investigation of thermal performance on engine cylinder: Effect of different geometry fins". Thermal Science, n. 00 (2023): 26. http://dx.doi.org/10.2298/tsci220917026a.
Abstract (sommario):
A fin is a surface that extends from an object to increase the rate of heat transfer to or from the environment for enhancing convection. The heat transfer performance of the engine cylinder fin is investigated in this study using fin geometries with various extensions, including rectangular, trapezium, and triangular segmental extensions. These are compared to fins without extension and showed a 5-13% increase in heat transfer rate. The primary idea behind adding extensions to finned surfaces is to increase the surface area of the fin in contact with the fluid/coolant flowing around it, resulting in a faster heat transfer rate.
28
Wang, Jing, Chao Ai, Xiao Yun, Zhikai Chen e Bing He. "Effects of 3D Roughness Parameters of Sandblasted Surface on Bond Strength of HVOF Sprayed WC-12Co Coatings". Coatings 12, n. 10 (1 ottobre 2022): 1451. http://dx.doi.org/10.3390/coatings12101451.
Abstract (sommario):
This work aims to reveal the effects of 3D roughness parameters of sandblasted surfaces on bond strength between thermal spray coatings and substrates. The investigation was carried out on the surface of AISI 4140, which were pretreated with automatic-sandblasting system. 3D topography and roughness parameters were analyzed by a 3D optical profiler. The bond strength of WC-12Co coatings was measured using a pull-off test method. Scanning electron microscope revealed that the morphology of the surface after sandblasting was rough. Furthermore, the surface topography was characterized by several irregular peaks and pits with different directions and no fixed orientation randomly distributed on sandblasted surface. The average values for surface roughness Sa = 4.84 ± 0.34 μm and bond strength = 32.8 ± 2.8 MPa were obtained. In terms of 3D roughness parameters, Sa, Sdr, Sdq and Sq were found to have more significant impact on affecting the bond strength, showing a nonlinear regression relationship. Furthermore, bond strength was positively correlated with Sa, Sdr and Sdq, while inversely proportional to Sq. This confirmed that a greater surface roughness of a sandblasted surface was not more conducive to the improvement of bond strength. The influence mechanism of each parameter was discussed, which was consistent with the regression mathematical model.
29
Zasimova, M. A., A. D. Podmarkova, N. G. Ivanov e A. A. Marinova. "Evaluation of CFD-predicted thermal comfort uncertainties based on a seated thermal manikin test case". IOP Conference Series: Earth and Environmental Science 1185, n. 1 (1 maggio 2023): 012041. http://dx.doi.org/10.1088/1755-1315/1185/1/012041.
Abstract (sommario):
Abstract The contribution presents the results of numerical simulation of 3D turbulent airflow and heat transfer around a seated thermal manikin in a model room with mixing ventilation. The main goal of the study is to evaluate the uncertainties caused by a CFD model. The room and the detailed thermal manikin geometry correspond to the experiment of P.V. Nielsen et al. (2007). The 3D computational model based on the RANS approach with the standard k-ε turbulence model is applied. The radiation effects are taken into account with the surface-to-surface radiation model. The study considers (1) the effect of the supply air flow rate variation and (2) the effect of the thermal manikin geometrical shape. For a particular parameters set, the results of numerical simulation are validated using the experimental data available (P.V. Nielsen et al.). The contribution is focused also on studying the effects of various heat transfer mechanisms on the airflow pattern and thermal comfort parameters: the baseline mixing ventilation scenario is compared with the buoyancy-dominated case.
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van Doremalen, Rob F. M., Jaap J. van Netten, Jeff G. van Baal, Miriam M. R. Vollenbroek-Hutten e Ferdinand van der Heijden. "Infrared 3D Thermography for Inflammation Detection in Diabetic Foot Disease: A Proof of Concept". Journal of Diabetes Science and Technology 14, n. 1 (14 giugno 2019): 46–54. http://dx.doi.org/10.1177/1932296819854062.
Abstract (sommario):
Background: Thermal assessment of the plantar surface of the foot using spot thermometers and thermal imaging has been proven effective in diabetic foot ulcer prevention. However, with traditional cameras this is limited to single spots or a two-dimensional (2D) view of the plantar side of foot, where only 50% of the ulcers occur. To improve ulcer detection, the view has to be extended beyond 2D. Our aim is to explore for proof of concept the combination of three-dimensional (3D) models with thermal imaging for inflammation detection in diabetic foot disease. Method: From eight participants with a current diabetic foot ulcer we simultaneously acquired a 3D foot model and three thermal infrared images using a high-resolution medical 3D imaging system aligned with three smartphone-based thermal infrared cameras. Using spatial transformations, we aimed to map thermal images onto the 3D model, to create the 3D visualizations. Expert clinicians assessed these for quality and face validity as +, +/-, -. Results: We could replace the texture maps (color definitions) of the 3D model with the thermal infrared images and created the first-ever 3D thermographs of the diabetic foot. We then converted these models to 3D PDF-files compatible with the hospital IT environment. Face validity was assessed as + in six and +/- in two cases. Conclusions: We have provided a proof of concept for the creation of clinically useful 3D thermal foot images to assess the diabetic foot skin temperature in 3D in a hospital IT environment. Future developments are expected to improve the image-processing techniques to result in easier, handheld applications and driving further research.
31
Karatza, Anna, Panagiotis Zouboulis, Iakovos Gavalas, Dionisis Semitekolos, Artemis Kontiza, Melpo Karamitrou, Elias P. Koumoulos e Costas Charitidis. "SLA Resins Modification by Liquid Mixing with Ceramic Powders Aiming at Mechanical Property and Thermal Stability Enhancement for Rapid Tooling Applications". Journal of Manufacturing and Materials Processing 6, n. 6 (26 ottobre 2022): 129. http://dx.doi.org/10.3390/jmmp6060129.
Abstract (sommario):
Stereolithography (SL) additive manufacturing process provides increased dimensional precision, smooth surface finish and printing resolution range in the order of magnitude of 100 μm, allowing to obtain intricate 3D geometries. The incorporation of ceramic-based inclusions within liquid resins enhances the thermal and mechanical properties of the final 3D printed component while improving the surface finishing of the final parts; in this way, it expands the range of process applications and reduces the post-processing steps. The proposed approach investigates the bulk modification of commercial SLA resins mixed with ceramic powders of Al2O3 (grain size 1–10 μm) and SiO2 (grain size 55–75 nm) aiming to improve 3D printed parts performance in terms of mechanical properties, dimensional stability and surface finishing compared with pure, unmodified resins. The produced materials were used for the development of inserts for injection moulding and were examined for their performance during the injection moulding process. The addition of particles in the nano- and micro-range is being employed to improve parts performance for rapid tooling applications whilst maintaining 3D printing accuracy, thermal and mechanical properties as well as achieving a smooth surface finishing compared with unmodified resins.
32
Liu, Xiaohua, Cheng Guo, Yandong Liu, Feng Wang e Yanfeng Feng. "The Interface Thermal Resistance Evolution between Carbide-Bonded Graphene Coating and Polymer in Rapid Molding for Microlens Array". Polymers 13, n. 14 (16 luglio 2021): 2334. http://dx.doi.org/10.3390/polym13142334.
Abstract (sommario):
Surface rapid heating process is an efficient and green method for large-volume production of polymer optics by adopting 3D graphene network coated silicon molds with high thermal conductivity. Nevertheless, the heat transfer mechanism including the interface thermal resistance evolution between 3D graphene network coating and polymer has not been thoroughly revealed. In this study, the interface thermal resistance model was established by simplifying the contact situation between the coating and polymethylmethacrylate (PMMA), and then embedding into the finite element method (FEM) model to study the temperature variations of PMMA in surface rapid heating process. Heating experiments for graphene network were then carried out under different currents to provide the initial heat for heat transfer model. In addition, residual stress of the PMMA lens undergoing the non-uniform thermal history during molding was presented by the simulation model together. Finally, the optimal molding parameters including heating time and pressure will be determined according to calculation results of the interface thermal resistance model and microlens array molding experiment was conducted to illustrate that the interface thermal resistance model can predict the temperature of the polymer to achieve a better filling of microlens array with smooth surface and satisfactory optical performance.
33
Salih, Shwan S. O., Idres I. A. Hamakhan e Abdulkader A. A. Abdulkader. "Investigation of Thermal Performance of 3D Printing Integrated Phase Change Materials in Building Structure". International Journal of Heat and Technology 40, n. 3 (30 giugno 2022): 843–48. http://dx.doi.org/10.18280/ijht.400325.
Abstract (sommario):
This paper aims to create an experimental building structure using 3D printing technology to reduce the interior temperature. Because of its sensitivity to high temperatures, particularly its low heat deflection temperature, and susceptibility to deterioration over time, the Polylactic acid (PLA) material has been preferred to print the layer. In this model, an effort was made to decrease the building's overall cooling load, which may result in a higher amount of ordinary power being required. For the study, a new model of the intended wall was developed and tested. The studies were carried out in two modes: the first without any PCM in the wall, and the second with an additional new model of PCM 3D-printing layer within the wall. The test results demonstrated that the PCM 3D-printing layer inside the wall building lowered the temperature of the outer wall surface, the inner wall surface, and subsequently the building temperature of the indoor area to a huge amount. The achievements are in the percentage peak temperature reduction of 9.8% for the wall's outer surface, 22.6% of the inner wall surface, and 13.4% of the room temperature. With the help of the PCM 3D-printing layer, the peak indoor temperature was decreased by 5℃.
34
Schultz, William C., Benny T. H. Tsang, Lars Bildsten e Yan-Fei Jiang. "Synthesizing Spectra from 3D Radiation Hydrodynamic Models of Massive Stars Using Monte Carlo Radiation Transport". Astrophysical Journal 945, n. 1 (1 marzo 2023): 58. http://dx.doi.org/10.3847/1538-4357/acb701.
Abstract (sommario):
Abstract Observations indicate that turbulent motions are present on most massive star surfaces. Starting from the observed phenomena of spectral lines with widths that are much larger than their thermal broadening (e.g., micro- and macroturbulence), and considering the detection of stochastic low-frequency variability (SLFV) in the Transiting Exoplanet Survey Satellite photometry, these stars clearly have large-scale turbulent motions on their surfaces. The cause of this turbulence is debated, with near-surface convection zones, core internal gravity waves, and wind variability being proposed. Our 3D gray radiation hydrodynamic (RHD) models previously characterized the convective dynamics of the surfaces, driven by near-surface convection zones, and provided reasonable matches to the observed SLFV of the most luminous massive stars. We now explore the complex emitting surfaces of these 3D RHD models, which strongly violate the 1D assumption of a plane-parallel atmosphere. By post-processing the gray RHD models with the Monte Carlo radiation transport code Sedona, we synthesize stellar spectra and extract information from the broadening of individual photospheric lines. The use of Sedona enables the calculation of the viewing angle and temporal dependence of spectral absorption line profiles. By combining uncorrelated temporal snapshots together, we compare the turbulent broadening from the 3D RHD models to the thermal broadening of the extended emitting region, showing that our synthesized spectral lines closely resemble the observed macroturbulent broadening from similarly luminous stars. More generally, the new techniques that we have developed will allow for systematic studies of the origins of turbulent velocity broadening from any future 3D simulations.
35
Akhloufi, Moulay A., e Benjamin Verney. "Multimodal Registration and Fusion for 3D Thermal Imaging". Mathematical Problems in Engineering 2015 (2015): 1–14. http://dx.doi.org/10.1155/2015/450101.
Abstract (sommario):
3D vision is an area of computer vision that has attracted a lot of research interest and has been widely studied. In recent years we witness an increasing interest from the industrial community. This interest is driven by the recent advances in 3D technologies, which enable high precision measurements at an affordable cost. With 3D vision techniques we can conduct advanced manufactured parts inspections and metrology analysis. However, we are not able to detect subsurface defects. This kind of detection is achieved by other techniques, like infrared thermography. In this work, we present a new registration framework for 3D and thermal infrared multimodal fusion. The resulting fused data can be used for advanced 3D inspection in Nondestructive Testing and Evaluation (NDT&E) applications. The fusion permits the simultaneous visible surface and subsurface inspections to be conducted in the same process. Experimental tests were conducted with different materials. The obtained results are promising and show how these new techniques can be used efficiently in a combined NDT&E-Metrology analysis of manufactured parts, in areas such as aerospace and automotive.
36
Quan, Guo-Zheng, Kun Yang, Yan-Ze Yu, Xue Sheng, Zhi-Hang Wen e Chao-Long Lu. "Response Surface of Speed-Loading Path to Grain Refinement during Current-Heating Compression at SAE 5137H Steel". Materials 15, n. 10 (12 maggio 2022): 3484. http://dx.doi.org/10.3390/ma15103484.
Abstract (sommario):
In thermal deformation of materials, grain refinement induced by dynamic recrystallization (DRX) is often pursued to obtain excellent mechanical properties. Here, the thermal deformation behaviors of SAE 5137H steel were investigated and characterized at temperature and strain rate range of 1123–1483 K and 0.01–10 s−1. Meanwhile, a design approach in speed-loading paths for grain refinement during current-heating compression was proposed, and these paths are linked to a typical three-dimensional (3D) response surface. Depending on the acquired stress–strain curves, the flow behaviors of this steel were analyzed and the typical 3D processing map was constructed to clarify the stable processing parameter domains during the continuous deformation process. Then, by the typical 3D processing map and microstructure observation, the 3D deformation mechanism map was constructed to connect the processing parameters and microstructural mechanisms. Subsequently, the 3D activation energy map was constructed to evaluate these deformation mechanisms, and the enhanced deformation mechanism map was constructed. Eventually, based on the enhanced deformation mechanism map, the speed-loading paths for SAE 5137H steel during current-heating compression were designed and they are mapped in a 3D response surface.
37
Karpova, Ekaterina, Gintautas Skripkiunas, Anastasiia Sedova e Yelyzaveta Tsimbalyuk. "Additive manufacturing of concrete wall structures". E3S Web of Conferences 281 (2021): 03007. http://dx.doi.org/10.1051/e3sconf/202128103007.
Abstract (sommario):
3D concrete printing is a perspective technology for sustainable construction and realization of sophisticated architectural projects. The current research proposes the thermal engineering calculation of wall structure based on the 3D printed concrete element of a total thickness of 150 mm with the internal air layer about 75 mm. The 3D printing mixture was designed with the addition of perlite as filler in the dosage of 8 % by weight of cement. The printing process was performed by the 3D printer of Contour Crafting type through the nozzle with a size of 20 mm. The thermal engineering calculation was implemented for the A++ energy consumption class. The wall structure based on the 3D printed concrete element with perlit has the thermal resistance comparable with one for wall structures based on brick and aerated concrete. The total thickness of the designed wall structure with 3D printed concrete element decreased by 100 mm and 50 mm in comparison with wall structures based on brick and aerated concrete, respectively. In addition to the thermal engineering calculations, the visual assessment of the surface quality of 3D printed concrete wall elements was performed.
38
Guilbert, V., R. Antoine, C. Heinkelé, O. Maquaire, S. Costa, C. Gout, R. Davidson, J. L. Sorin, B. Beaucamp e C. Fauchard. "FUSION OF THERMAL AND VISIBLE POINT CLOUDS : APPLICATION TO THE VACHES NOIRES LANDSLIDE, NORMANDY, FRANCE". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2020 (12 agosto 2020): 227–32. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2020-227-2020.
Abstract (sommario):
Abstract. In this paper, we present a methodology to fusion 3D visible and thermal infrared (TIR) information on a coastal landslide area located in Normandy, France. A reflex and TIR camera on-board an Unmanned Aerial Vehicle are utilized to generate a 3D visible and a thermal model using Photogrammetry. A Python-written algorithm is then used to associate the thermal scalar on the TIR model to the closest point on the visible point cloud, before applying α-blending to ease the visualization of both data sets. This methodology leads to the generation of an integrated 3D thermo-visible model, allowing the direct analysis of the surface temperatures, visible data and geometric configuration of the landslide.
39
Nuwal, Nakul, Deborah A. Levin e Igor D. Kaganovich. "Excitation of surface waves in 3D ion beam neutralization". Physics of Plasmas 30, n. 4 (aprile 2023): 042109. http://dx.doi.org/10.1063/5.0131447.
Abstract (sommario):
Neutralization of beams with 2D and 3D geometries by the electrons emitted from an external source is studied using particle-in-cell simulations. Our work reveals that the high-energy electrons excite Trivelpiece–Gould (TG) surface waves in the beams with 3D axisymmetric geometries. These high-energy electrons are generated because of a large amplitude electrostatic solitary wave (ESW) that forms near the electron source and has an electric potential amplitude more than three times the electron thermal energy. We also find that surface wave excitation only happens when the beam radius is large enough at the ion source to attract enough electrons that could form the large amplitude ESW. A comparison of the 3D TG surface wave dispersion relation with an expression for 2D surface waves reveals that they become excited in 3D axisymmetric but not in 2D planar beam because of a higher phase speed requirement in the latter case.
40
Borkowska, Monika, e Radosław Mrówczyński. "Triptycene Based 3D Covalent Organic Frameworks (COFs)—An Emerging Class of 3D Structures". Symmetry 15, n. 9 (21 settembre 2023): 1803. http://dx.doi.org/10.3390/sym15091803.
Abstract (sommario):
Covalent Organic Frameworks (COFs) are a newly emerged class of porous materials consisting of organic building blocks linked by strong covalent bonds. The physical and chemical properties of COFs, i.e., modularity, porosity, well-developed specific surface area, crystallinity, and chemical-thermal stability, make them a good application material, especially in the aspects of adsorption and gas separation. The organic compositions of their building blocks also render them with biocompatible properties; therefore, they also have potential in biomedical applications. Depending on the symmetry of the building blocks, COF materials form two-dimensional (2D COF) or three-dimensional (3D COF) crystal structures. 3D COF structures have a higher specific surface area, they are much lighter due to their low density, and they have a larger volume than 2D COF crystals, but, unlike the latter, 3D COF crystals are less frequently obtained and studied. Selecting and obtaining suitable building blocks to form a stable 3D COF crystal structure is challenging and therefore of interest to the chemical community. Triptycene, due to its 3D structure, is a versatile building block for the synthesis of 3D COFs. Polymeric materials containing triptycene fragments show good thermal stability parameters and have a very well-developed surface area. They often tend to be characterized by more than one type of porosity and exhibit impressive gas adsorption properties. The introduction of a triptycene backbone into the structure of 3D COFs is a relatively new procedure, the results of which only began to be published in 2020. Triptycene-based 3D COFs show interesting physicochemical properties, i.e., high physical stability and high specific surface area. In addition, they have variable porosities with different pore diameters, capable of adsorbing both gases and large biological molecules. These promising parameters, guaranteed by the addition of a triptycene backbone to the 3D structure of COFs, may create new opportunities for the application of such materials in many industrial and biomedical areas. This review aims to draw attention to the symmetry of the building blocks used for COF synthesis. In particular, we discussed triptycene as a building block for the synthesis of 3D COFs and we present the latest results in this area.
41
Lee, Wondu, e Jooheon Kim. "Highly Thermal Conductive and Electrical Insulating Epoxy Composites with a Three-Dimensional Filler Network by Sintering Silver Nanowires on Aluminum Nitride Surface". Polymers 13, n. 5 (25 febbraio 2021): 694. http://dx.doi.org/10.3390/polym13050694.
Abstract (sommario):
In this study, a new fabrication technique for three-dimensional (3D) filler networks was employed for the first time to prepare thermally conductive composites. A silver nanowire (AgNW)– aluminum nitride (AlN) (AA) filler was produced by a polyol method and hot-pressed in mold to connect the adjacent fillers by sintering AgNWs on the AlN surface. The sintered AA filler formed a 3D network, which was subsequently impregnated with epoxy (EP) resin. The fabricated EP/AA 3D network composite exhibited a perpendicular direction thermal conductivity of 4.49 W m−1 K−1 at a filler content of 400 mg (49.86 vol.%) representing an enhancement of 1973% with respect to the thermal conductivity of neat EP (0.22 W m−1 K−1). Moreover, the EP/AA decreased the operating temperature of the central processing unit (CPU) from 86.2 to 64.6 °C as a thermal interface material (TIM). The thermal stability was enhanced by 27.28% (99 °C) and the composites showed insulating after EP infiltration owing to the good insulation properties of AlN and EP. Therefore, these fascinating thermal and insulating performances have a great potential for next generation heat management application.
42
Chen, Jike, Wenfeng Zhan, Peijun Du, Long Li, Jiufeng Li, Zihan Liu, Fan Huang, Jiameng Lai e Junshi Xia. "Seasonally disparate responses of surface thermal environment to 2D/3D urban morphology". Building and Environment 214 (aprile 2022): 108928. http://dx.doi.org/10.1016/j.buildenv.2022.108928.
43
Yataghene, Mourad, e Jack Legrand. "A 3D-CFD model thermal analysis within a scraped surface heat exchanger". Computers & Fluids 71 (gennaio 2013): 380–99. http://dx.doi.org/10.1016/j.compfluid.2012.10.026.
44
Galkin, Aleksandr. "Equivalent thermal resistance of the road surface". Арктика и Антарктика, n. 3 (marzo 2022): 129–38. http://dx.doi.org/10.7256/2453-8922.2022.3.38777.
Abstract (sommario):
The design and construction of highways in the cryolithozone is associated with a number of difficulties, which are determined not only by geocryological and climatic operating conditions, but also by the complexity of the actual forecast of the thermal regime of road coverings and foundations. Many thermal calculations to substantiate technical solutions for the protection of highways in the cryolithozone from negative cryogenic phenomena are based on the determination and selection of a given thermal resistance of the structural layers of the pavement. The purpose of these studies was to assess the feasibility of using equivalent thermal resistance in modeling thermal processes and to determine the error in calculations that we make by replacing the layered pavement structure with an equivalent one. Simple engineering dependences are obtained that allow us to determine the error in calculations when using equivalent thermal resistance. The calculation of the thermal resistance of the three-layer construction of the pavement is made. It is established that for a three-layer pavement structure, the error value in the calculation of thermal resistance is directly related to the degree of deviation of the values of the thermal conductivity coefficient of the materials of individual layers from each other. Moreover, the parameters of the inequality of thermal conductivity coefficients for individual structural layers when determining the minimum calculation error are functionally related to each other. The results of variant numerical calculations are presented in the form of 3D and 2D graphs, which allow us to visually assess the influence of the studied parameters on the relative error of calculating the thermal resistance of the pavement.
45
Abreu de Souza, Mauren, Daoana Carolaine Alka Cordeiro, Jonathan de Oliveira, Mateus Ferro Antunes de Oliveira e Beatriz Leandro Bonafini. "3D Multi-Modality Medical Imaging: Combining Anatomical and Infrared Thermal Images for 3D Reconstruction". Sensors 23, n. 3 (1 febbraio 2023): 1610. http://dx.doi.org/10.3390/s23031610.
Abstract (sommario):
Medical thermography provides an overview of the human body with two-dimensional (2D) information that assists the identification of temperature changes, based on the analysis of surface distribution. However, this approach lacks spatial depth information, which can be enhanced by adding multiple images or three-dimensional (3D) systems. Therefore, the methodology applied for this paper generates a 3D point cloud (from thermal infrared images), a 3D geometry model (from CT images), and the segmented inner anatomical structures. Thus, the following computational processing was employed: Structure from Motion (SfM), image registration, and alignment (affine transformation) between the 3D models obtained to combine and unify them. This paper presents the 3D reconstruction and visualization of the respective geometry of the neck/bust and inner anatomical structures (thyroid, trachea, veins, and arteries). Additionally, it shows the whole 3D thermal geometry in different anatomical sections (i.e., coronal, sagittal, and axial), allowing it to be further examined by a medical team, improving pathological assessments. The generation of 3D thermal anatomy models allows for a combined visualization, i.e., functional and anatomical images of the neck region, achieving encouraging results. These 3D models bring correlation of the inner and outer regions, which could improve biomedical applications and future diagnosis with such a methodology.
46
Slámečka, Karel, Petr Šesták, Tomáš Vojtek, Marta Kianicová, Jana Horníková, Pavel Šandera e Jaroslav Pokluda. "A Fractographic Study of Bending/Torsion Fatigue Failure in Metallic Materials with Protective Surface Layers". Advances in Materials Science and Engineering 2016 (2016): 1–6. http://dx.doi.org/10.1155/2016/8952657.
Abstract (sommario):
Results are given of a fractographic study of biaxial in-phase bending/torsion fatigue fractures in specimens made of nitrided steel and nickel-based superalloy with protective coatings (diffusion coatings and plasma-sprayed thermal barrier coatings). Fracture surfaces were examined by optical and scanning electron microscopes while stereophotogrammetry and optical profilometry were employed to obtain 3D surface data of selected fracture surface regions. The studied materials exhibited a wide range of fracture mechanisms depending on the microstructure and applied mechanical loading.
47
Song, Xiao Zhong. "Micro Electrical Discharge Machining Thermal Effect on Micro-Cracks Generation on Silicon Material". Materials Science Forum 1047 (18 ottobre 2021): 41–49. http://dx.doi.org/10.4028/www.scientific.net/msf.1047.41.
Abstract (sommario):
Various novel 3D micro machining technologies were researched and developed for silicon micro mechanical system fabrication. Micro EDM is one of them. The material removal mechanism is thermal sparking erosion and is completely independent with regards to the crystalline orientation of silicon, therefore there is no orientation constraint in processing the complex 3D geometry of silicon wafers. As thermal sparking implied, the process features local area high temperature melting and evaporating, and this characteristic has an adverse side-effect on the sparked surface integrity. One important concern is the generation of micro cracks, which would provide an adverse effect on the fatigue life of the micro feature element made of silicon. For this consideration, in this paper, with the experiment and SEM picture analysis approach, the author explored the micro crack generation characteristics on mono crystalline silicon wafers under micro EDM with available sparking energies and on the different crystal orientation surface machining. The generation of micro cracking is not only related with the sparking energy but also related with the crystalline orientation. The {100} orientation is the strongest surface to resist crack generation. For a strong-doped P type silicon wafer, there exists a maximum crack energy threshold. If single sparking energy is over this threshold, micro cracks unavoidably would be generated on any orientation surface. Two types of chemical etching post processes that can remove cracks on sparked surfaces are also tested and discussed.
48
Salandin, Andrea, Alberto Quintana-Gallardo, Vicente Gómez-Lozano e Ignacio Guillén-Guillamón. "The First 3D-Printed Building in Spain: A Study on Its Acoustic, Thermal and Environmental Performance". Sustainability 14, n. 20 (14 ottobre 2022): 13204. http://dx.doi.org/10.3390/su142013204.
Abstract (sommario):
The first 3D-printed building in Spain is the object of this study, and it is presented and physically described herein from different points of view. This study combines on-site measurements, simulations, and a life cycle assessment to assess some relevant parameters concerning the acoustic, thermal and environmental performance of the 3D-printed house. The main objectives are to analyze whether the house complies with the acoustic and thermal regulations and to assess whether it can act as a sustainable alternative to conventional masonry construction, especially when time plays an important role. The build surface (3D prototype) of the house is approximately 23 m2. The internal space includes a living room (12.35 m2), a bedroom (7.36 m2) and a bathroom (3.16 m2). The total surface of the house is 22.87 m2 and it has a volume of 64.03 m3. The acoustic insulation was measured according to the ISO 9869-1:2014 standard. In terms of the acoustic insulation, the sound reduction index was tested following the guidelines of the ISO 140-5:1999 standard. Additionally, the study includes a comparative life cycle assessment comparing the 3D-printed façade with two conventional wall typologies. The 3D-printed house displays an excellent thermal performance, with a measured thermal transmittance of 0.24 Wm−2K−1, suitable for all Spanish climate zones. Regarding the acoustic insulation, the measured global sound reduction indexes of the façades range from 36 to 45 dB, which is adequate for areas with noise levels of up to 75 dB. The environmental results indicate that 3D-printed façade manufacturing emits 30% more CO2e than a façade constructed using concrete blocks and 2% less than a masonry block wall. Overall, this study shows that, in addition to its multiple advantages in terms of the construction time, the studied 3D-printed house has similar acoustic, thermal and environmental traits to the most common construction typologies. However, it cannot be considered a sustainable construction method due to its high amount of cement.
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Li, Bo, Yanquan Geng e Yongda Yan. "Nano/Microscale Thermal Field Distribution: Conducting Thermal Decomposition of Pyrolytic-Type Polymer by Heated AFM Probes". Nanomaterials 10, n. 3 (7 marzo 2020): 483. http://dx.doi.org/10.3390/nano10030483.
Abstract (sommario):
In relevant investigations and applications of the heated atomic force microscope (AFM) probes, the determination of the actual thermal distribution between the probe and the materials under processing or testing is a core issue. Herein, the polyphthalaldehyde (PPA) film material and AFM imaging of the decomposition structures (pyrolytic region of PPA) were utilized to study the temperature distribution in the nano/microscale air gap between heated tips and materials. Different sizes of pyramid decomposition structures were formed on the surface of PPA film by the heated tip, which was hovering at the initial tip–sample contact with the preset temperature from 190 to 220 °C for a heating duration ranging from 0.3 to 120 s. According to the positions of the 188 °C isothermal surface in the steady-state probe temperature fields, precise 3D boundary conditions were obtained. We also established a simplified calculation model of the 3D steady-state thermal field based on the experimental results, and calculated the temperature distribution of the air gap under any preset tip temperature, which revealed the principle of horizontal (<700 nm) and vertical (<250 nm) heat transport. Based on our calculation, we fabricated the programmable nano-microscale pyramid structures on the PPA film, which may be a potential application in scanning thermal microscopy.
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Peng, Rui Tao, Fang Lu, Xin Zi Tang e Yuan Qiang Tan. "3D Finite Element Analysis of Prestressed Cutting". Advanced Materials Research 591-593 (novembre 2012): 766–70. http://dx.doi.org/10.4028/www.scientific.net/amr.591-593.766.
Abstract (sommario):
In order to reveal the adjustment principle of prestressed cutting on the residual stress of hardened bearing steel GCr15, a three-dimensional thermal elastic-viscoplastic finite element model was developed using an Arbitrary Lagrangian Eulerian (ALE) formulation. Several key simulation techniques including the material constitutive model, constitutive damage law and contact with friction were discussed, simulation of chip formation during prestressed cutting was successfully conducted. At the prestresses of 0 MPa, 341 MPa and 568 MPa, distributions of residual stress on machined surface were simulated and experimentally verified. The results indicated that residual compressive stress on machined surface were achieved and actively adjusted by utilizing the prestressed cutting method; meanwhile, within the elastic limit of bearing steel material, the higher applied prestress leads to the more prominent compressive residual stress in the surface layer and subsequently the higher fatigue resistance of the part.