Academic literature on the topic 'Struts (Computer file)'
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Journal articles on the topic "Struts (Computer file)"
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Sicoe, Casian Teodor, Cătălina Bichir, and Mugurel Constantin Rusu. "The Optic Strut—CBCT Pneumatization Pattern and Prevalence." Applied Sciences 11, no. 13 (2021): 5797. http://dx.doi.org/10.3390/app11135797.
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(1) Background: The optic strut (OS) is a critical landmark for clinoid and paraclinoid surgical interventions. To our knowledge, the current literature only mentioned the OS as a possibility for a lesser sphenoidal wing (LSW) pneumatization path, without a proper study of the pneumatization patterns and prevalence within this structure. Thus, our aim was to fill in the missing information. (2) Methods: A retrospective study on 80 cone beam computed tomography (CBCT) files was conducted to assess the prevalence and the origins of pneumatization within the OS. (3) Results: The pneumatization patterns of the OS were: 56.25% from the sphenoid sinus, 1.25% from the posterior ethmoid air cells (PEAC), and 10% from Onodi cells (ONC). Simultaneous pneumatization of unique origin within the lesser sphenoidal wing (LSW) was found in 26.25% from the sphenoid sinus, 1.25% from PEAC, and 5% from ONC. Communication between both LSW roots through pneumatization was found in 6.25% of the files. (4) Conclusions: A careful radiological examination should precede clinical diagnosis and surgical interventions in the paraclinoid area to evaluate postoperative surgical risks and possible diffusion patterns for infection. Additionally, pneumatization within the OS alters its morphological features and thus, its utility as a landmark.
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McMillan, Matthew Leslie, Marten Jurg, Martin Leary, and Milan Brandt. "Programmatic generation of computationally efficient lattice structures for additive manufacture." Rapid Prototyping Journal 23, no. 3 (2017): 486–94. http://dx.doi.org/10.1108/rpj-01-2016-0014.
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Purpose Additive manufacturing (AM) enables the fabrication of complex geometries beyond the capability of traditional manufacturing methods. Complex lattice structures have enabled engineering innovation; however, the use of traditional computer-aided design (CAD) methods for the generation of lattice structures is inefficient, time-consuming and can present challenges to process integration. In an effort to improve the implementation of lattice structures into engineering applications, this paper aims to develop a programmatic lattice generator (PLG). Design/methodology/approach The PLG method is computationally efficient; has direct control over the quality of the stereolithographic (STL) file produced; enables the generation of more complex lattice than traditional methods; is fully programmatic, allowing batch generation and interfacing with process integration and design optimization tools; capable of generating a lattice STL file from a generic input file of node and connectivity data; and can export a beam model for numerical analysis. Findings This method has been successfully implemented in the generation of uniform, radial and space filling lattices. Case studies were developed which showed a reduction in processing time greater than 60 per cent for a 3,375 cell lattice over traditional CAD software. Originality/value The PLG method is a novel design for additive manufacture (DFAM) tool with unique advantages, including full control over the number of facets that represent a lattice strut, allowing optimization of STL data to minimize file size, while maintaining suitable resolution for the implemented AM process; programmatic DFAM capability that overcomes the learning curve of traditional CAD when producing complex lattice structures, therefore is independent of designer proficiency and compatible with process integration; and the capability to output both STL files and associated data for numerical analysis, a unique DFAM capability not previously reported.
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Al-Barqawi, Mohammad O., Benjamin Church, Mythili Thevamaran, Dan J. Thoma, and Adeeb Rahman. "Experimental Validation and Evaluation of the Bending Properties of Additively Manufactured Metallic Cellular Scaffold Structures for Bone Tissue Engineering." Materials 15, no. 10 (2022): 3447. http://dx.doi.org/10.3390/ma15103447.
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The availability of additive manufacturing enables the fabrication of cellular bone tissue engineering scaffolds with a wide range of structural and architectural possibilities. The purpose of bone tissue engineering scaffolds is to repair critical size bone defects due to extreme traumas, tumors, or infections. This research study presented the experimental validation and evaluation of the bending properties of optimized bone scaffolds with an elastic modulus that is equivalent to the young’s modulus of the cortical bone. The specimens were manufactured using laser powder bed fusion technology. The morphological properties of the manufactured specimens were evaluated using both dry weighing and Archimedes techniques, and minor variations in the relative densities were observed in comparison with the computer-aided design files. The bending modulus of the cubic and diagonal scaffolds were experimentally investigated using a three-point bending test, and the results were found to agree with the numerical findings. A higher bending modulus was observed in the diagonal scaffold design. The diagonal scaffold was substantially tougher, with considerably higher energy absorption before fracture. The shear modulus of the diagonal scaffold was observed to be significantly higher than the cubic scaffold. Due to bending, the pores at the top side of the diagonal scaffold were heavily compressed compared to the cubic scaffold due to the extensive plastic deformation occurring in diagonal scaffolds and the rapid fracture of struts in the tension side of the cubic scaffold. The failure in struts in tension showed signs of ductility as necking was observed in fractured struts. Moreover, the fractured surface was observed to be rough and dull as opposed to being smooth and bright like in brittle fractures. Dimple fracture was observed using scanning electron microscopy as a result of microvoids emerging in places of high localized plastic deformation. Finally, a comparison of the mechanical properties of the studied BTE scaffolds with the cortical bone properties under longitudinal and transverse loading was investigated. In conclusion, we showed the capabilities of finite element analysis and additive manufacturing in designing and manufacturing promising scaffold designs that can replace bone segments in the human body.
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Chaddad-Neto, Feres, Marcos Devanir Silva da Costa, Bruno Santos, et al. "Reproducibility of a new classification of the anterior clinoid process of the sphenoid bone." Surgical Neurology International 11 (September 12, 2020): 281. http://dx.doi.org/10.25259/sni_133_2020.
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Background: Pneumatization of the anterior clinoid process (ACP) affects paraclinoid region surgery, this anatomical variation occurs in 6.6–27.7% of individuals, making its preoperative recognition essential given the need for correction based on the anatomy of the pneumatized process. This study was conducted to evaluate the reproducibility of an optic strut-based ACP pneumatization classification by presenting radiological examinations to a group of surgeons. Methods: Thirty cranial computer tomography (CT) scans performed from 2013 to 2014 were selected for analysis by neurosurgery residents and neurosurgeons. The evaluators received Google Forms with questionnaires on each scan, DICOM files to be manipulated in the Horos software for multiplanar reconstruction, and a collection of slides demonstrating the steps for classifying each type of ACP pneumatization. Interobserver agreement was calculated by the Fleiss kappa test. Results: Thirty CT scans were analyzed by 37 evaluators, of whom 20 were neurosurgery residents and 17 were neurosurgeons. The overall reproducibility of the ACP pneumatization classification showed a Fleiss kappa index of 0.49 (95% confidence interval: 0.49–0.50). The interobserver agreement indices for the residents and neurosurgeons were 0.52 (0.51–0.53) and 0.49 (0.48–0.50), respectively, and the difference was statistically significant (P < 0.00001). Conclusion: The optic strut-based classification of ACP pneumatization showed acceptable concordance. Minor differences were observed in the agreement between the residents and neurosurgeons. These differences could be explained by the residents’ presumably higher familiarity with multiplanar reconstruction software.
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Guo, Kai, and Boming Zhao. "Deformation Intensity Distribution and Zoning of Seismic Deformation Fields in Near-Fault Areas." Symmetry 14, no. 2 (2022): 239. http://dx.doi.org/10.3390/sym14020239.
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To describe the distribution law of the degree of stratigraphic deformation in the cross-fault region under the influence of fault dislocation, the concept of deformation intensity is introduced, and a computational model of the coseismic deformation field in the cross-fault region is established based on the dislocation model theory and the rich fault inversion parameters in the Sichuan–Tibet region. According to the deformation law of a typical earthquake in Yushu, key sections and parameters are selected for analysis. The results show that the maximum dislocation of the deformation field in the cross-fault region decays from the fault rupture to the surface, and the deformation influence extends from the upper edge of the fault to the surface, with an overall funnel-shaped symmetric distribution. The deformation intensity is elliptically distributed in the vertical profile. The maximum deformation of the strata across the fault within the burial depth of the structure is fitted to fill the lack of the existing statistical equation of coseismic deformation without considering the burial depth factor. Finally, the strata are zoned by deformation intensity according to the degree of deformation to provide a reference for the seismic protection of structures in the near-fault area.
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Ma, Beihai, Manoj Narayanan, Shanshan Liu, Sheng Tong, and U. (Balu) Balachandran. "Development of High Dielectric Strength Ceramic Film Capacitors for Advanced Power Electronics**." Journal of Microelectronics and Electronic Packaging 10, no. 1 (2013): 1–7. http://dx.doi.org/10.4071/imaps.369.
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Ceramic film capacitors with high dielectric constant and high breakdown strength are promising for use in advanced power electronics, which would offer higher performance, improved reliability, and enhanced volumetric and gravimetric efficiencies. We have grown lead lanthanum zirconate titanate (PLZT) on nickel foils and platinized silicon (PtSi) sub-strates by chemical solution deposition. A buffer layer of LaNiO3 (LNO) was deposited on the nickel foils prior to the deposition of PLZT. We measured the following electrical properties for PLZT films grown on LNO buffered Ni and PtSi substrates, respectively: remanent polarization, ∼25.4 μC/cm2 and ∼10.1 μC/cm2; coercive electric field, ∼23.8 kV/cm and ∼27.9 kV/cm; dielectric constant at room temperature, ∼1300 and ∼1350; and dielectric loss at room temperature, ∼0.06 and ∼0.05. Weibull analysis determined the mean breakdown strength to be 2.6 MV/cm and 1.5 MV/cm for PLZT films grown on LNO buffered Ni and PtSi substrates, respectively. Residual stress analysis by x-ray diffraction revealed compressive stress of ∼−520 MPa in the ∼2-μm-thick PLZT grown on LNO buffered Ni foil, but a tensile stress of ∼210 MPa in the ∼2-μm-thick PLZT grown on PtSi substrates.
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Agati, Giuliano, Francesca Di Gruttola, Serena Gabriele, Domenico Simone, Paolo Venturini, and Domenico Borello. "Water washing of axial flow compressors: numerical study on the fate of injected droplets." E3S Web of Conferences 197 (2020): 11015. http://dx.doi.org/10.1051/e3sconf/202019711015.
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In turbomachinery applications blade fouling represents a main cause of performance degradation. Among the different techniques currently available, online water washing is one of the most effective in removing deposit from the blades. Since this kind of washing is applied when the machine is close to design conditions, injected droplets are strongly accelerated when they reach the rotor blades and the understanding of their interaction with the blades is not straightforward. Moreover, undesirable phenomena like blades erosion or liquid film formation can occur. The present study aims at assessing droplets dragging from the injection system placed at the compressor inlet till the first stage rotor blades, with a focus on droplets impact locations, on the washing process and the associated risk of erosion. 3D numerical simulations of the whole compressor geometry (up to the first rotor stage) are performed by using Ansys Fluent to account for the asymmetric distribution of the sprays around of the machine struts, IGV and rotor blades. The simulations are carried out by adopting the k-ε realizable turbulence model with standard wall functions, coupled with the discretephase model to track injected droplets motion. Droplets-wall interaction is also accounted for by adopting the Stanton-Rutland model which define a droplet impact outcome depending on the impact conditions. The induced erosion is evaluated by adopting an erosion model previously developed by some of the authors and implemented in Fluent through the use of a User Defined Function (UDF). Two sets of simulations are performed, by considering the rotor still and rotating, representative of off-line and on-line water washing conditions, respectively. In the rotating simulation, the Multiple Reference Frame Model is used. The obtained results demonstrate that the washing process differs substantially between the fixed and the rotating case. Moreover, to quantify the water washing effectiveness and the erosion risk, new indices were introduced and computed for the main components of the machine. These indices can be considered as useful prescriptions in the optimization process of water washing systems.
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Urazova, Svetlana Leonidovna. "Screen Communications As a Form of Socialization and Individualization." Journal of Flm Arts and Film Studies 7, no. 2 (2015): 142–49. http://dx.doi.org/10.17816/vgik72142-149.
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Common exposure to various kinds of mobile and stationary devices based on screen technologies produce substantiation for the term screen communications. The relevancy of its usage is specified, also the principles of functioning in context of updating social practices and multimedia informational space are substantiated in the article. The issue is due to the fact that the term screen communications has not yet been put into academic usage, unlike such terms as communication, mass communication and social communication. Nevertheless contemporary social practices for using the screen (cell phone, e-book, tablet, etc.) have turned into a daily routine and even demonstrate screen-phobia. The evolution of the technologies, new media (multimedia, multi-platforms), growth of information flows, form and content diversity of informational products, socialization effect and accumulation of empirical experience urge society to resort to the screen for receiving information (film-, video-, TV-production, Internet sites, social networks, computers, cell phones, tablets, e-books, electronic billboards, videoinformational systems, etc.). The article analyzes characteristics of well-known communications forms and types when superimposed to the term screen communications. The problem raised a need for thorough analysis of screen communications which different strata of society master; moreover, a great significance of studying peculiarities of screen culture in the digital era is emphasized. The article cites information about the emergence of Generation C, formed by social networks (a lecture on Nielsen Consumer 360 Conference). The Connected Collective Consumer has a distinguished identity and is ready for self-expression (ideas, cultural projects, etc.) within the group. As a conclusion it substantiates the nonlinearity of the social systems development, including social networks which are exposed to both the socialization effect and diversification and disintegration processes, which leads to a communication connections collapse.
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Salih, Moaz, John J. G. Reijmer, Ammar El Husseiny, et al. "Controlling Factors on Petrophysical and Acoustic Properties of Bioturbated Carbonates: (Upper Jurassic, Central Saudi Arabia)." Applied Sciences 11, no. 11 (2021): 5019. http://dx.doi.org/10.3390/app11115019.
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Many of the world’s productive Jurassic reservoirs are intensively bioturbated, including the sediments of the Upper Jurassic Hanifa Formation. Hydrocarbon exploration and production from such reservoirs require a reliable prediction of petrophysical properties (i.e., porosity, permeability, acoustic velocity) by linking and assessment of ichnofabrics and trace fossils and determining their impact on reservoir quality. In this study, we utilized outcrop carbonate samples from the Hanifa Formation to understand the main controlling factors on reservoir quality (porosity and permeability) and acoustic velocity of bioturbated carbonates, by using thin-section petrography, SEM, XRD, CT scan, porosity, permeability, and acoustic velocity measurement. The studied samples are dominated by Thalassinoides burrows that have burrow intensity ranging from ~4% to 27%, with porosity and permeability values ranging from ~1% to 20%, and from 0.002 mD up to 1.9 mD, respectively. Samples with coarse grain-filled burrows have higher porosity (average µ = 14.44% ± 3.25%) and permeability (µ = 0.56 mD ± 0.55) than samples with fine grain-filled burrows (µ = 6.56% ± 3.96%, and 0.07 mD ± 0.16 mD). The acoustic velocity is controlled by an interplay of porosity, bioturbation, and mineralogy. Samples with relatively high porosity and permeability values (>10% and >0.1 mD) have lower velocities (<5 km/s) compared to tight samples with low porosities and permeabilities (<10% and <0.1 mD). The mineralogy of the analyzed samples is dominated by calcite (~94% of total samples) with some quartz content (~6% of total samples). Samples characterized with higher quartz (>10% quartz content) show lower velocities compared to the samples with lower quartz content. Bioturbation intensity, alone, has no control on velocity, but when combined with burrow fill, it can be easier to discriminate between high and low velocity samples. Fine grain-filled burrows have generally lower porosity and higher velocities (µ = 5.46 km/s) compared to coarse grain-filled burrows (µ = 4.52 km/s). Understanding the main controlling factor on petrophysical properties and acoustic velocity of bioturbated strata can enhance our competency in reservoir quality prediction and modeling for these bioturbated units.
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Letov, Nikita, Pavan Tejaswi Velivela, Siyuan Sun, and Yaoyao Fiona Zhao. "Challenges and Opportunities in Geometric Modeling of Complex Bio-Inspired Three-Dimensional Objects Designed for Additive Manufacturing." Journal of Mechanical Design 143, no. 12 (2021). http://dx.doi.org/10.1115/1.4051720.
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Abstract Ever since its introduction over five decades ago, geometric solid modeling has been crucial for engineering design purposes and is used in engineering software packages such as computer-aided design (cad), computer-aided manufacturing, computer-aided engineering, etc. Solid models produced by cad software have been used to transfer geometric information from designers to manufacturers. Since the emergence of additive manufacturing (AM), a CAD file can also be directly uploaded to a three-dimensional (3D) printer and used for production. AM techniques allow manufacturing of complex geometric objects such as bio-inspired structures and lattice structures. These structures are shapes inspired by nature and periodical geometric shapes consisting of struts interconnecting in nodes. Both structures have unique properties such as significantly reduced weight. However, geometric modeling of such structures has significant challenges due to the inability of current techniques to handle their geometric complexity. This calls for a novel modeling method that would allow engineers to design complex geometric objects. This survey paper reviews geometric modeling methods of complex structures to support bio-inspired design created for AM which includes discussing reasoning behind bio-inspired design, limitations of current modeling approaches applied to bio-inspired structures, challenges encountered with geometric modeling, and opportunities that these challenges reveal. Based on the review, a need for a novel geometric modeling method for bio-inspired geometries produced by AM is identified. A framework for such a bio-inspired geometric modeling method is proposed as a part of this work.
Dissertations / Theses on the topic "Struts (Computer file)"
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Ryu, Kyungbum. "The bias-stress effect in pentacene organic thin-film transistors." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/58176.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references.<br>Organic thin-film transistors (OTFTs) are promising for flexible large-area electronics. However, the bias-stress effect (BSE) in OTFTs causes operational instability that limits the usefulness of the OTFT technology in a wide range of circuit applications. Currently, most existing studies on OTFT BSE are inadequate because of one or more of the following reasons. First, they study the BSE on OTFTs with thermally grown Si0 2, which cannot be used in flexible electronics due to its high deposition temperature. Secondly, they use devices with no encapsulation, and the devices degrade by exposure to H₂0 and 0₂ in ambient air. The existence of such other degradation mechanisms complicates the interpretation of the BSE measurements on these devices. Lastly, they do not study the BSE systematically to fully identify its dependencies on various stress conditions. This work addresses these issues by systematically studying the electrical characteristics of the BSE in integrated pentacene OTFTs with polymer gate dielectric and encapsulation. Pentacene is used as the model organic semiconductor because it is the most widely used organic semiconductor for OTFTs. The measurements reveal that the BSE results from carriers that are trapped at the semiconductor/dielectric interface. The BSE can be accurately modeled by a shift in the gate voltage, [delta]V, which equals qN/Ci, where N is the density of trapped carriers, and Ci is the channel capacitance per unit area. The BSE occurs only when both gate field and channel carriers are present and the drain current does not increase the BSE. Because the density of traps is limited, when there are more carriers induced in the channel than available number of traps, AV saturates at a constant value, which is directly proportional to the trap density in the channel.<br>(cont.) This behavior of [delta]V saturation despite the presence of free carriers in the channel is observed for the first time in a TFT. Through the temperature measurements, we identify that the source of the long time constants for trapping is the high energy barriers for carriers to be trapped. The effective energy barrier is found to be 0.8 eV for the measured pentacene OTFTs. The time constants associated with the traps are dispersed due to the disorder in the pentacene and gate dielectric. The dependencies of the BSE to various stress conditions are modeled, which allows prediction of [delta]V for different stress times and voltages. The model is used to estimate the implication of the BSE on circuit applications and usable lifetime. Full recovery of the original I-V characteristics occur when the bias stress is removed. The recovery is found to have time dependency and thermal activation energy that is similar to the BSE implying that the recovery mechanism is similar to that of the BSE. The application of the negative VSG accelerates recovery, which serves as evidence that the recovery is achieved by detrapping of the trapped carrier. Possible mechanisms for the BSE and its recovery are discussed based on the experimental observations. A new annealing process which improves mobility, contact resistance, and operational stability has been developed. Experimentally the annealing process increased mobility from 0.03 to 0.05 cm2/Vs and decreased contact resistance from 185 to 38 K[ohm]-cm. The overall improvement in stability is over eight times for a wide range of stress conditions. The stability is found to be increased by the reduction of the trap density and the decrease of the trapping rate.<br>by Kevin Kyungbum Ryu.<br>Ph.D.
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Hammon, Steven Jay. "Preserving Optical Confinement in PECVD SiO2 Waveguides by Control of Thin-Film Stress." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6288.
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Researchers at Brigham Young University (BYU) have developed an optical biosensor that can quickly analyze a sample to detect any type of nucleic acid based organism, such as viruses or bacteria. The biosensor's reliability over time is compromised due to water absorbing into the SiO2 waveguides of the chip. It was hypothesized that keeping the thin-film stress of the waveguides close to zero would slow or stop water absorption from occurring. Completion of this thin-film study relied upon a new plasma enhanced chemical vapor deposition (PECVD) machine and a new 3-D optical profilometer, both of which were installed in the BYU cleanroom. The new PECVD machine was much more capable than previous machines at controlling deposition parameters and was a critical component in accurately controlling the intrinsic stress of deposited films. The 3-D optical profilometer provided us a way to accurately measure the intrinsic stress of the films. Rib waveguides made from different stressed SiO2 films were fabricated over anti-resonant reflecting optical waveguide (ARROW) layers. The wafers were baked out, cleaved, and their initial throughputs recorded. All waveguides were placed in a humid environment and were removed periodically to check their optical throughput. The resulting measurements were normalized to the highest measured throughput to determine how throughput was changing over time. Rib waveguides with the lowest stressed SiO2 had the slowest rate of throughput change, dropping to 50% of the original throughput after 40 days in the humid environment. The +50 MPa stressed waveguides performed next best, dropping to 20% of the original throughput after 40 days. The +100 MPA stressed waveguides dropped to 20% throughput after 16 days while the -50 MPa stressed wafers dropped to 20% optical throughput after 7 days. Keeping the stress of the film as low as possible helped reduce the rate of water absorption, but did not eliminate it completely. A method involving the use of high index difference buried channel waveguides is shown to be effective at stopping the effects of water absorption in our waveguides.
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Akyildiz, Oncu. "Computer Simulation Of Grain Boundary Grooving By Anisotropic Surface Drift Diffusion Due To Capillary, Electromigration And Elastostatic Forces." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12612034/index.pdf.
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The aim of this study is to develop a theoretical basis and to perform computational experiments for understanding the grain boundary (GB) grooving in polycrystalline thin film metallic conductors (interconnects) by anisotropic surface diffusion due to capillary, electromigration and elastostatic forces.
To this end, irreversible thermo&ndash<br>kinetics of surfaces and interfaces with triple junction singularities is elaborated, and the resulting well-posed moving boundary value problem is solved using the front&ndash<br>tracking method. To simulate the strain conditions of the interconnects during service, the problem is addressed within the framework of isotropic linear elasticity in two dimensions (plane strain condition). In the formulation of stress induced surface diffusion, not only the contribution due
to elastic strain energy density (ESED) but also that of the elastic dipole tensor interactions (EDTI) between the stress field and the mobile atomic species (monovacancies) is considered. In computation of the elastostatic and electrostatic fields the indirect boundary element method (IBEM) with constant and straight boundary elements is utilized. The resulted non&ndash<br>linear partial differential equation is solved numerically by Euler&rsquo<br>s method of finite differences.
The dynamic computer simulation experiments identify well known GB groove shapes and shed light on their growing kinetics. They also allow generating some scenarios under several conditions regarding to the applied force fields and/or physicochemical parameters.
The destruction of groove symmetry, termination of the groove penetration with isotropic surface diffusivity, ridge/slit formations with anisotropic diffusivity and the role played by the wetting parameter are all identified for electromigration conditions. The kinetics of accelerated groove deepening with an applied tensile stress is examined in connection with GB cavity growth models in the literature and a diffusive micro-crack formation is reported at the groove tip for high stresses. On the other hand, the use of EDTI provided a means to dynamically simulate GB ridges under compressive stress fields with surface diffusion. An incubation time for hillock growth and a crossover depth over which GB migration becomes energetically favorable is defined and discussed in this context.
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Rizzante, Fabio Antonio Piola. "Mechanical and physical properties assessment of Bulk Fill resin composites." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/25/25148/tde-31082018-181145/.
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The achievement of predictable and long lasting adhesive restorations in posterior teeth have always been a major objective of studies in the context of materials and techniques development. The use of bulk fill composites could provide better outcomes, but it is important to assess their physico-mechanical properties, responsible for their clinical behavior. The purpose of the present study was to assess the mechanical and physical properties of bulk fill composites. The composites were divided into 2 groups according to their viscosity. For low viscosity composites, the present study assessed: Surefill SDR flow (SDR), X-tra Base (XB), Filtek Bulk Fill Flowable (FBF), and Filtek Z350XT Flow (Z3F- control); and for high viscosity composites: Tetric Evo Ceram Bulk Fill (TBF), X-tra Fil (XF), Filtek Bulk Fill (FBP), Admira Fusion x-tra (ADM) and Filtek Z350 XT (Z3XT- control). Composites were assessed through shrinkage stress test (using 12 and 24mm3 of composite in a custom device adapted in an Universal Testing Machine); volumetric shrinkage (using 64mm3 of composite placed on a Teflon mold and scanned in a micro computed tomography/CT); Youngs modulus (through a 3-point bending test device adapted in an Universal Testing Machine); microhardness and depth of cure tests (using longitudinal Knoop microhardness). All data was evaluated regarding their homogeneity using Shapiro-Wilk test. For polymerization stress, 3-way Variance Analysis (ANOVA) was used. Considering Volumetric Shrinkage, Youngs Modulus, Microhardness and Depth of Cure, one-way ANOVA was used. All ANOVA tests were followed by Tukeys test and 5% was adopted as significance level. Shrinkage stress test with 12mm3 showed SDR, TBF and XF generating the lowest stress after 300s, followed by other high viscosity composites (ADM, FBF, XB and FBP/Z3XT). The regular low viscosity composite (Z3F) generated the highest stress for all assessed times. Considering the same test, with 24mm3, after 300s, SDR, FBP and ADM generated similar stress, followed by TBF and XF. Low viscosity bulk fill composites generated lower stress than Z3F. Considering Youngs modulus, low viscosity composites (SDR, FBF, XB and Z3F) showed the lowest values, followed by ADM and TBF. The other high viscosity composites (Z3XT, FBP and XF) showed the highest values. For microhardness test, all low viscosity composites showed lower values (FBF being the lowest). For high viscosity composites, Z3XT showed the highest values, followed by XF, FBP/TBF and ADM. Assessing depth of cure, regular composites showed lower values when compared with bulk fill composites. All bulk fill composites showed adequate depth of cure over 4.5mm (microhardness 80% of initial reading). SDR and XB showed the highest depth of cure. All high viscosity bulk fill composites generated lower volumetric shrinkage than regular composites. All low viscosity bulk fill composites showed similar volumetric shrinkage when compared to the regular composites (Z3F and Z3XT). Bulk fill composites show characteristics that allow their use in larger increments (i.e. volumetric shrinkage and polymerization stress similar or lower when compared with regular composites). Nonetheless, the mechanical properties of bulk fill composites were widely variable, being important to individually assess each material previously to its clinical application.<br>A obtenção de restaurações adesivas previsíveis e duradouras em dentes posteriores sempre foi objetivo de estudos na área de desenvolvimento de materiais e técnicas. O uso de resinas compostas do tipo bulk fill pode possibilitar melhores resultados, porém é importante o estudo de suas propriedades físico-mecânicas, responsáveis por seus comportamentos clínicos. O objetivo do presente estudo foi o de avaliar as propriedades físicas e mecânicas das resinas bulk fill. As resinas foram divididas em 2 grupos de acordo com sua viscosidade. Para resinas de baixa viscosidade, o presente estudo avaliou: Surefill SDR flow (SDR), X-tra Base (XB), Filtek Bulk Fill Flowable (FBF) e Filtek Z350XT Flow (Z3F-controle); e, para alta viscosidade: Tetric Evo Ceram Bulk Fill (TBF), X-tra Fil (XF), Filtek Bulk Fill (FBP), Admira Fusion x-tra (ADM) e Filtek Z350 XT (Z3XT-controle). As resinas foram avaliadas em relação à tensão de polimerização (utilizando 12 e 24mm3 de resina adaptadas em um dispositivo adaptado a uma máquina de testes universal); contração volumétrica (utilizando 64mm3 de resina composta inserida em um molde de Teflon e escaneada em um micro-tomógrafo/CT), modulo de Young (através de um dispositivo de flexão em 3 pontos adaptado a uma máquina de testes universal), microdureza e profundidade de polimerização (utilizando microdureza Knoop). Todos os resultados foram avaliados em relação à homogeneidade utilizando o teste de Shapiro-Wilk. Para avaliação da tensão de polimerização, foi empregada a Análise de Variância (ANOVA) a 3 critérios. Para as analyses de contração volumétrica, Módulo de Young, microdureza e profundidade de polimerizaçao, ANOVA a um critério foi empregada. Todas as Análises de Variância foram seguidas pelo teste de Tukey e 5% foi adotado como nível de significância. A tensão de polimerização com 12mm3 demonstrou que SDR, TBF e XF geraram valores significantemente mais baixos após 300s, seguidas por outras resinas de alta viscosidade (ADM, FBF, XB e FBP/Z3XT). A resina convencional de baixa viscosidade (Z3F) gerou valores de tensão significantemente mais elevados para todos os tempos avaliados. Considerando o mesmo teste, com 24mm3, após 300s, SDR, FBP e ADM geraram valores estatisticamente inferiores, seguidas por TBF e XF. As resinas bulk fill de baixa visocidade geraram menor tensão de polimerização que a Z3F. Considerando o modulo de Young, resinas de baixa viscosidade (SDR, FBF, XB e Z3F) apresentaram valores significantemente inferiores, seguidas por ADM e TBF. As outras resinas de alta viscosidade (Z3XT, FBP e XF) apresentaram valores significantemente mais elevados. Para o teste de microdureza, todas as resinas de baixa viscosidade apresentaram valores inferiores (FBF apresentou o menor). Para as resinas de alta viscosidade, Z3XT apresentou os valores mais elevados, seguida por XF, FBP/TBF e ADM. Para profundidade de polimerização, resinas compostas convencionais apresentaram valores signifixantemente mais baixos quando comparadas com resinas bulk fill. Todas as resinas bulk fill apresentaram profundidade de polimerização adequada até pelo menos 4,5mm (microdureza 80% da leitura inicial/superfície). SDR e XB apresentaram os valores mais altos de profundidade de polimerização. Todas as resinas bulk fill de alta viscosidade geraram menor contração volumétrica que resinas compostas convencionais. Todas as resinas bulk fill de baixa viscosidade apresentaram contração volumétrica similar às resinas convencionais (Z3F e Z3XT). Resinas compostas bulk fill apresentaram características que possibilitam sua indicação para serem empregadas em grandes incrementos (contração volumétrica e tensão de polimerização similar ou inferiores às resinas convencionais, além de maior profundidade de polimerização). No entanto, as propriedades mecânicas variaram grandemente entre as resinas estudadas sendo importante uma avaliação individual de cada material previamente ao seu uso clínico.
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Awwad, Sari Moh'd Ismaeil. "Tracking and fine-grained activity recognition in depth videos." Thesis, 2016. http://hdl.handle.net/10453/90070.
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University of Technology Sydney. Faculty of Engineering and Information Technology.<br>Tracking and activity recognition in video are arguably two of the most active topics within the field of computer vision and pattern recognition. Historically, tracking and activity recognition have been performed over conventional video such as color or grey-level frames, either of which contains significant clues for the identification of targets. While this is often a desirable feature within the context of video surveillance, the use of video for activity recognition or for tracking in privacy-sensitive environments such as hospitals and care facilities is often perceived as intrusive. For this reason, this PhD research has focused on providing tracking and activity recognition solely from depth videos which offer a naturally privacy-preserving visual representation of the scene at hand. Depth videos can nowadays be acquired with inexpensive and highly-available commercial sensors such as Microsoft Kinect and Asus Xtion. The two main contributions of this research have been the design of a specialised tracking algorithm for tracking in depth data, and a fine-grained activity recognition approach for recognising activities in depth video. The proposed tracker is an extension of the popular Struck algorithm, an approach that leverages a structural support vector machine (SVM) for tracking. The main contributions of the proposed tracker include a dedicated depth feature based on local depth patterns, a heuristic for handling view occlusions in depth frames, and a technique for keeping the number of support vectors within a given budget, so as to limit computational costs. Conversely, the proposed fine-grained activity recognition approach leverages multi-scale depth measurements and a Fisher-consistent multi-class SVM. In addition to the novel approaches for tracking and activity recognition, in this thesis we have canvassed and developed a practical computer vision application for the detection of hand hygiene at a hospital. This application was developed in collaboration with clinical researchers from the Intensive Care Unit of Sydney’s Royal Prince Alfred Hospital. Experiments presented through the thesis confirm that the proposed approaches are effective, and either outperform the state of the art or significantly reduce the need for sensor instrumentation. The outcomes of the hand-hygiene detection were also positively received and assessed by the clinical research unit.
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Chow, Melissa Jane. "Impact of Mechanical Stress on the Electrical Stability of Flexible a-Si TFTs." Thesis, 2011. http://hdl.handle.net/10012/6387.
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The development of functional flexible electronics is essential to enable applications such as conformal medical imagers, wearable health monitoring systems, and flexible light-weight displays. Intensive research on thin-film transistors (TFTs) is being conducted with the goal of producing high-performance devices for improved backplane electronics. However, there are many challenges regarding the performance of devices fabricated at low temperatures that are compatible with flexible plastic substrates. Prior work has reported on the change in TFT characteristics due to mechanical strain, with especially extensive data on the effect of strain on field-effect mobility. This thesis investigates the effect of gate-bias stress and elastic strain on the long-term stability of flexible low-temperature hydrogenated amorphous silicon (a-Si:H) TFTs, as the topic has yet to be explored systematically.
An emphasis was placed on bias-stress measurements over time in order to obtain information on the physical mechanisms of instability. Drain current was measured over various intervals of time to track the degradation of devices due to metastability, and results were then compared across devices of various sizes under tensile, compressive, and zero strain. Transfer characteristics of the TFTs were also measured under the different conditions, to allow for extraction of parameters that would provide insight into the instability mechanisms. In addition to parameter extraction, the degradation and recovery of TFT output current was quantitatively compared for various bias-stress times across the different levels of strain. Finally, the instability mechanisms are modelled with a Markov system to further examine the effect of strain on long-term TFT operation.
From the analysis of results, it was found that shallow charge trapping in the dielectric is the main mechanism of instability for short bias stress times, and did not seem to be greatly affected by strain. For longer bias stress times of over 10000 seconds, defect creation in the a-Si:H becomes a more significant contributor to instability. Both tension and compression increased defect creation compared to TFTs with zero applied strain. Compression appeared to cause the greatest increase in the rate of defect formation, likely by weakening Si-Si bonds in the a-Si:H. Tension appeared to cause a less significant increase, possibly due to a strengthening of some proportion of the Si-Si bonds caused by the slight elongation of bond length or because the applied tension relieves intrinsic compressive stress in a-Si:H film. A longer conduction path and greater dielectric area appears to increase the bias-stress and strain-related effects. Therefore reducing device size should increase the reliability of flexible TFTs.
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Pundt, Astrid. "Nanoskalige Metall-Wasserstoff-Systeme." 2001. http://hdl.handle.net/11858/00-1735-0000-0006-B458-2.
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Burk, Doris. "Physiologische, anatomische und chemische Aspekte der Regulation der Wurzelwasseraufnahme bei Rotbuche, Kiefer und Birke auf zwei unterschiedlich wasserversorgten Standorten." Doctoral thesis, 2006. http://hdl.handle.net/11858/00-1735-0000-0006-B6DC-6.
Full textBooks on the topic "Struts (Computer file)"
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The Struts framework: Practical guide for Java programmers. Morgan Kaufmann Publishers, 2003.
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Inc, ebrary, ed. Apache Struts 2 web application development: Design, develop, test, and deploy your web applications using the Struts 2 framework. Packt Publishing Ltd., 2009.
Find full textBook chapters on the topic "Struts (Computer file)"
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Matsumoto, Kanta, Tomokazu Matsui, Hirohiko Suwa, and Keiichi Yasumoto. "Stress Prediction Using Per-Activity Biometric Data to Improve QoL in the Elderly." In Lecture Notes in Computer Science. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-09593-1_15.
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AbstractTo improve the QoL of the elderly, it is essential to predict their stress states. In general, the stress state varies from day to day or time to time depending on what activities are performed and how long/strong. However, most existing studies predict the stress state using biometric data and specific activities (e.g., sleep time, exercise time and amount) as explanatory variables, but do not consider all daily living activities. Therefore, it is necessary to predict the stress state by linking various daily living activities and biometric information. In this paper, we propose a method to improve the prediction accuracy of stress estimation by linking daily living activities data and biometric data. Specifically, we construct a machine learning model in which the objective variable is the result of a stress status questionnaire obtained every morning and evening, and the explanatory variables are the types of daily living activities performed in the 24 h prior to the questionnaire and the feature values calculated from the biometric data during each of the performed activities. The results of the evaluation experiments using the one month data collected from five elderly households, show that the proposed method (using per-activity biometric features) improves the prediction accuracy by more than 10% from the baseline methods (with biometric features without considering activities).
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Barakhov, Konstantin P., and Igor M. Taranenko. "Influence of Joint Edge Shape on Stress Distribution in Adhesive Film." In Integrated Computer Technologies in Mechanical Engineering - 2021. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94259-5_12.
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Zolnikov, Konstantin P., Dmitrij S. Kryzhevich, and Aleksandr V. Korchuganov. "Regularities of Structural Rearrangements in Single- and Bicrystals Near the Contact Zone." In Springer Tracts in Mechanical Engineering. Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-60124-9_14.
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AbstractThe chapter is devoted to the analysis of the features of local structural rearrangementsin nanostructured materialsunder shear loadingand nanoindentation. The study was carried out using molecular dynamics-based computer simulation. In particular, we investigated the features of symmetric tilt grain boundary migration in bcc and fcc metals under shear loading. The main emphasis was on identifying atomic mechanisms responsible for the migration of symmetric tilt grain boundaries. We revealed that grain boundaries of this type can move with abnormally high velocities up to several hundred meters per second. The grain boundary velocity depends on the shear rate and grain boundary structure. It is important to note that the migration of grain boundary does not lead to the formation of structural defects. We showed that grain boundary moves in a pronounced jump-like manner as a result of a certain sequence of self-consistent displacements of grain boundary atomic planes and adjacent planes. The number of atomic planes involved in the migration process depends on the structure of the grain boundary. In the case of bcc vanadium, five planes participate in the migration of the Σ5(210)[001] grain boundary, and three planes determine the Σ5(310)[001] grain boundary motion. The Σ5(310)[001] grain boundary in fcc nickel moves as a result of rearrangements of six atomic planes. The stacking order of atomic planes participating in the grain boundary migration can change. A jump-like manner of grain boundary motion may be divided into two stages. The first stage is a long time interval of stress increase during shear loading. The grain boundary is motionless during this period and accumulates elastic strain energy. This is followed by the stage of jump-like grain boundary motion, which results in rapid stress drop. The related study was focused on understanding the atomic rearrangements responsible for the nucleation of plasticity near different crystallographic surfaces of fcc and bcc metals under nanoindentation. We showed that a wedge-shaped region, which consists of atoms with a changed symmetry of the nearest environment, is formed under the indentation of the (001) surface of the copper crystallite. Stacking faults arise in the (111) atomic planes of the contact zone under the indentation of the (011) surface. Their escape on the side free surface leads to a step formation. Indentation of the (111) surface is accompanied by nucleation of partial dislocations in the contact zone subsequent formation of nanotwins. The results of the nanoindentation of bcc iron bicrystal show that the grain boundary prevents the propagation of structural defects nucleated in the contact zone into the neighboring grain.
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Boudreault-Fournier, Alexandrine. "Street Net and Electronic Music in Cuba." In Audible Infrastructures. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780190932633.003.0007.
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Cuba has one of the lowest internet penetration rates in the world. This encourages Cubans to create alternative ways of coping with digital scarcity, including hidden wi-fi antennas and ethernet cables strung over streets and rooftops, and physical networks of digital media circulation that rely on memory sticks and other portable devices. These alternative networks counter the inefficiency and unreliability of the official media infrastructures, providing the population with access to digital media and to what presently circulates outside of Cuba. Electroacoustic and electronic musicians benefit from these physical networks of circulation by accessing text, audio, and image files, as well as cracked software, anti-virus definitions, and plug-ins. This chapter explores the creative impacts of evolving media infrastructures on the production and circulation of digital media in Cuba, looking at how wires, waves, and webs affect the creation of new collectives and new music during a period of rapid economic and political transformation. It addresses the strategies adopted by electronic musicians to access programs and software, and to create music in a context of digital scarcity and through illicit and legal infrastructures. The chapter discusses telecommunications networks and the digitalization of music on this island, where the creative strategies for dealing with such infrastructures (or the lack thereof) contribute to new fields of musical practice. Digital culture in Cuba is about alternative local intranets as much as the official global internet, hand-to-hand data sharing as much as peer-to-peer file transfers, human “servers” as much as computer servers.
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Pantic, Maja. "Affective Computing." In Encyclopedia of Multimedia Technology and Networking, Second Edition. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-014-1.ch003.
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We seem to be entering an era of enhanced digital connectivity. Computers and Internet have become so embedded in the daily fabric of people’s lives that people simply cannot live without them (Hoffman, Novak, & Venkatesh, 2004). We use this technology to work, to communicate, to shop, to seek out new information, and to entertain ourselves. With this ever-increasing diffusion of computers in society, human–computer interaction (HCI) is becoming increasingly essential to our daily lives. HCI design was first dominated by direct manipulation and then delegation. The tacit assumption of both styles of interaction has been that the human will be explicit, unambiguous, and fully attentive while controlling the information and command flow. Boredom, preoccupation, and stress are unthinkable even though they are “very human” behaviors. This insensitivity of current HCI designs is fine for well-codified tasks. It works for making plane reservations, buying and selling stocks, and, as a matter of fact, almost everything we do with computers today. But this kind of categorical computing is inappropriate for design, debate, and deliberation. In fact, it is the major impediment to having flexible machines capable of adapting to their users and their level of attention, preferences, moods, and intentions. The ability to detect and understand affective states of a person we are communicating with is the core of emotional intelligence. Emotional intelligence (EQ) is a facet of human intelligence that has been argued to be indispensable and even the most important for a successful social life (Goleman, 1995). When it comes to computers, however, not all of them will need emotional intelligence and none will need all of the related skills that we need. Yet human–machine interactive systems capable of sensing stress, inattention, and heedfulness, and capable of adapting and responding appropriately to these affective states of the user are likely to be perceived as more natural, more efficacious, and more trustworthy. The research area of machine analysis of human affective states and employment of this information to build more natural, flexible (affective) HCI goes by a general name of affective computing, introduced first by Picard (1997).
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Yuzevych, Volodymyr, and Bohdan Koman. "MATHEMATICAL AND COMPUTER MODELING OF INTERPHASE INTERACTION IN HETEROGENEOUS SOLID STRUCTURES." In Theoretical and practical aspects of the development of modern scientific research. Publishing House “Baltija Publishing”, 2022. http://dx.doi.org/10.30525/978-9934-26-195-4-14.
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The aim of this work was to develop a mathematical model and computer modelling of interphase interaction, mechanical stresses and adhesion mechanisms between mechanically inhomogeneous media (different phases). Methodology. For the system "metal – dielectric" we use a macroscopic approach, which corresponds to the ratio of non-equilibrium thermodynamics and physics of solid surfaces. Let’s consider the system of equations and boundary conditions for describing the change of energy parameters (σh, γ), which characterize the thermodynamic state of the system of contacting bodies. Method for calculating the main energy parameters (interfacial energy – γm, interfacial tension – σm, work of adhesion – Aadand energy of adhesive bonds – γad) in complex solid-state structures containing boundary phases is proposed. Based on the basic equations of nonequilibrium thermodynamics and surface physics a mathematical model of the interphase boundary is designed. A comparative analysis of the features of interphase interaction in the systems "metal-metal", "metal-semiconductor" and "metal-dielectric" on the example of interacting systems "Cu – Zn", "Cu – Si" and "Cu – quartz". It is established that the most sensitive parameter in the analysis of interphase interactions is the interphase energy γm.A model of mechanical stress formation in the "condensate-substrate" system is proposed. In particular, internal stresses in metal condensates are caused by changes in the value of interphase energy parameters (primarily interfacial tension) in the substrate-nanocondensate system and due to phase-forming processes accompanied by changes in surface energy in the condensate volume during its formation. The resulting internal stresses in metal condensates are an integral result of the action of statistically distributed on the plane of the film local stresses. Such phenomena are due to the anisotropy of the energy parameters of the interphase interaction in the condensate plane. Behavior analysis of energy and adhesion parameters can be used to predict the results of interphase interaction in order to select contact pairs to create thermodynamically stable structures with predicted values of energy parameters of interphase interaction, a certain type of chemical bond and a given level of mechanical stresses.
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Wang, Qing, Matthias Ihme, Yi-fan Chen, Vivian Yang, Fei Sha, and John Anderson. "Towards real-time predictions of large-scale wildfire scenarios using a fully coupled atmosphere-fire physical modelling framework." In Advances in Forest Fire Research 2022. Imprensa da Universidade de Coimbra, 2022. http://dx.doi.org/10.14195/978-989-26-2298-9_67.
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With the changing climate, fire-exclusion, and expansion of wildland-urban interfaces, the frequency and severity of wildfires are expected to increase, putting substantial stress on fire management and authorities to mitigate the risk of wildfires. Improved physical models in conjunction with advanced high-performance computing resources offer new opportunities for operational use in examining potential fire-spread scenarios and planning. This work presents an open-source, high-fidelity modelling framework for simulating large-scale wildfire scenarios, taking into consideration atmospheric/fire coupling, complex terrain, and heterogeneous fuel loading. The framework is implemented using the TensorFlow programming environment on tensor processing units (TPUs). TPUs are a dedicated high-performance computing architecture to accelerate machine-learning applications and high-performance scientific computing. This framework solves the Favre-filtered reacting Navier-Stokes equations and the unclosed terms describing turbulence/chemistry interaction and turbulence transport are modelled using large-eddy simulation (LES) closures. Wildfire dynamics is described by a one-step solid-fuel pyrolysis/combustion model that is coupled to atmospheric flow dynamics using a Boussinesq-type approximation. A second-order finite-difference discretization is employed in a variable-density, low-Mach number formulation to discretize the governing equations, and an immersed-boundary method is adapted to represent complex terrain. In conjunction with the coupled atmosphere/fire model and physical models for turbulence/atmosphere/fire interaction, the resulting simulation framework enables high-resolution simulations (with spatial resolution below 2m) of large-scale fires that cover up to ~100,000 acres. Following the summary of validation results against a prescribed fire experiment to assess the overall accuracy at well-controlled conditions, we employ this coupled atmosphere/fire modelling framework to simulate a large-scale wildfire scenario that is representative of the 2017 California Tubb’s fire. To this end, we extract the terrain of the North Bay region of Calistoga and Santa Rosa, spanning an area of 20×20 km2, and consider a North-Eastern wind. The simulation results illustrate the rapid fire-spread dynamics and the coupling of the fire with the terrain and atmosphere. With relevance to operational and research applications that include parametric studies to examine effects of wind, fuel-density, other environmental factors, and fire-management strategies, we discuss the scalability and further extensions of the physical fidelity towards enabling real-time applications on TPU-compute architectures.
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Berk, Laura E. "Learning in Classrooms." In Awakening Children's Minds. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195124859.003.0010.
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A visitor entering Tamara’s combined kindergarten/first-grade classroom is likely to be struck by its atmosphere of calm purposefulness, given that so much is happening at once. On a typical day, twenty-two 5- to 7-year-olds are busy working on diverse activities throughout the room. At ten o’clock one Tuesday, several children were in the writing center—one preparing a thank you note and four others collaborating on making a list of the names of everyone in the class. In the reading center, five children were browsing the shelves or reading books, in pairs and individually. At a table next to shelves filled with math materials, four children worked in pairs on a problem requiring them to choose items from a restaurant menu without exceeding their budget. Yet another pair was immersed in an interactive computer activity about plants as sources of foods. Tamara was seated at a table, reading and discussing a story with a cluster of six children. The children in Tamara’s class come from a variety of ethnic and socioeconomic backgrounds. About three-fourths live in the middle-income neighborhood surrounding the school, located in a midsize Midwestern city. The rest are bussed from a housing project for low-income families several miles away. Two children have reading disabilities, and one has a speech and language delay. Several times a week, a learning disabilities teacher and a speech therapist come to the classroom to assist these children. Tamara’s students present great variations in experiences, knowledge, and academic skills. She uses this diversity to enrich their learning. The classroom is organized into seven clearly defined activity centers. The largest is the reading center, which doubles as a class meeting area. Others are the writing center, the math center, the life science center, the physical science center, the art center, and the imaginative play/extended project center. Computers can be found in the life science and writing centers. All centers are brimming with materials—on shelves and in boxes and baskets, clearly labeled and within children’s easy reach. And each center contains a table to serve as a comfortable workspace for collaborative and individual pursuits.
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Ehrenfeld, David. "Sherlock Nero and Us." In Swimming Lessons. Oxford University Press, 2002. http://dx.doi.org/10.1093/oso/9780195148527.003.0010.
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Some people have a drink when they get home from work—a martini, a beer. Maybe two or three. Life is especially stressful in the twenty-first century. The same indecent forces that are destroying nature are disrupting our working lives as well. Who will own the company tomorrow? Will there be a “reduction in force” or some other euphemism for the ax? When is the next reorganization coming? Is my ten or twenty years of faithful service an asset or, more likely, a sign of obsolescence and suspicious loyalty to bosses and co-workers now out of favor or working for other companies? How am I to answer the fax that arrived at 4:00 p.m., the one that seemed to contradict the fax that arrived at 11:00? When will I find time to fill out the questionnaire from the Resource Management Office, and does it take precedence over the Goals Enhancement Strategy questionnaire that came from the Administrative Services Division? Are my computer files compatible with the new software system, and, if so, why did the box on the screen say, “This paragraph is un-readable. Do you wish to substitute a standard paragraph?” Just what is our real work, anyway? Alcohol can take the edge off stress, but it is not everyone’s consolation. Some choose television or the Internet; mine is to pick up one of the scores of detective novels that I keep close to hand and plunge in. Then I can forget for a little while the vice presidents, deans, and other academic, corporate-style bosses who do their best to make life in the modern university an unproductive misery. In this way I can put out of mind, temporarily, the pleas of students who don’t understand why there are no courses to take and the ravings of colleagues who can’t figure out how to cope with the contradictory, impossible demands placed on them. Why should detective stories be, for so many, such a good and entertaining way of escaping from reality? That they are is clear; billions of copies have been sold.
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Lienhard, John H. "Looking Inside the Inventive Mind." In The Engines of Our Ingenuity. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780195135831.003.0005.
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An inventor—any creative person—knows to look under the surface of what things seem to be, to learn what they are. I have been able to find only one constant in the creative mind. It is that surprise is the hidden face of the coin of invention. In their operetta Pinafore, Gilbert and Sullivan warn us: . . . Things are seldom what they seem, Skim milk masquerades as cream; Highlows pass as patent leathers; Jackdaws strut in peacock’s feathers. . . . For example, an engineer designing a highway system wants to include crossroads between the major arteries. Common sense says that crossroads will increase driver options and speed traffic. Only very keen insight, or a complex computer analysis, reveals that crossroads tend to make matters worse. They often create localized traffic jams where none would otherwise occur. We are caught off guard when common sense fails us. Yet it is clear we would live in a deadly dull world if common sense alone were sufficient to lead us through all the mazes around us. If what we learn is no more than what we expect to learn, then we have learned nothing at all. Sooner or later, every student of heat flow is startled to find out that insulation on a small pipe can sometimes increase heat loss. Common sense is the center of gravity we return to after our flights of fancy. But it is the delicious surprise—the idea that precedes expectation—that makes science, technology, and invention such a delight. A wonderful old expression calls creativity “a fine madness,” and it is. Invention lies outside the common ways and means. If it is sane to respond predictably to reality, then invention surely is madness. A well-known riddle shows us something of the way that madness works. You are asked to connect nine dots, in a square array, with four straight lines. Each line has to continue from the end of the last line. The problem seems to have no solution.
Conference papers on the topic "Struts (Computer file)"
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Shih, T. I.-P., Y. L. Lin, M. K. Chyu, and S. Gogineni. "Computations of Film Cooling From Holes With Struts." In ASME 1999 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/99-gt-282.
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Computations were performed to study the three-dimensional flow and heat transfer on a flat plate cooled by jets, injected from a plenum through one row of film-cooling holes in which each hole is fitted with a strut in the form of a circular cylinder. Three different configurations of the film-cooling hole were investigated: without strut, with streamwise strut, and with spanwise strut. For all configurations, the film-cooling holes are inclined at 35°, and the coolant-to-mainflow density and mass-flux ratios are 1.6 and 0.5, respectively. The focus of this study is to understand how struts in holes affect film cooling jets and their interactions with the mainflow in forming a protective layer of cooler fluid over the plate. This computational study is based on the ensemble-averaged conservation equations of mass, momentum (compressible Navier-Stokes), and energy. Effects of turbulence was modeled by a low Reynolds number k-ω closure known as the shear-stress-transport (SST) model. Solutions were generated by a cell-centered finite-volume method that uses third-order accurate flux-difference splitting of Roe with limiters, multigrid acceleration of a diagonalized ADI scheme with local time stepping, and patched/overlapped structured grids. In the computations, the flow is resolved not just in the cooling-jet/mainflow interaction region, but also inside the film-cooling holes and in the plenum. Computed results for adiabatic effectiveness for the case without struts were compared with experimental data, and reasonably good agreements were obtained.
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Li, Fenghua. "Research and Application on validation.xml of Struts2 Framework Verify File." In 2015 International Industrial Informatics and Computer Engineering Conference. Atlantis Press, 2015. http://dx.doi.org/10.2991/iiicec-15.2015.323.
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Kothawade, Saurabh, Dean Michael Ancajas, Koushik Chakraborty, and Sanghamitra Roy. "Mitigating NBTI in the physical register file through stress prediction." In 2012 IEEE 30th International Conference on Computer Design (ICCD 2012). IEEE, 2012. http://dx.doi.org/10.1109/iccd.2012.6378662.
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Javadi, Aliyar, Khodayar Javadi, Mohamad Taeibi-Rahni, and Mohammad Reza Keimasi. "Reynolds Stress Turbulence Models for Prediction of Shear Stress Terms in Cross Flow Film Cooling — Numerical Simulation." In ASME 2002 Pressure Vessels and Piping Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/pvp2002-1586.
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Reynolds stress models are computationally more complex and time consuming but, have the potential of greater accuracy and wider applicability. Turbulent cross flows and film cooling have highly complex characteristics. In this work, we computationally simulated a three-dimensional, separated hole film cooling problem of flow over a flat plate, using Reynolds stress model (RSM) with wall function and zonal (κ-ε)/(κ-ω) turbulence model (shear stress transport model or SST). The Reynolds number of the jet was 4700. Our computational domain included the space above plate plus the film cooling jet channel. In our numerical simulation, the SIMPLE finite volume method with a non-uniform staggered grid was implemented. Our results were compared with Ajersch et al. experimental and numerical work’s (κ-ε turbulence model). Also, they were compared with Keimasi and Taeibi-Rahani’s numerical simulation work (SST turbulence model). Comparison between the measured and computed results show, that RSM/SST turbulence model in our work has better agreement with experimental data in most cases.
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Khosrowjerdi, M., Robert C. Azar, Ali Salehi, and G. H. Nazari. "Computer-Aided Design of Bicycles." In ASME 1991 International Computers in Engineering Conference and Exposition. American Society of Mechanical Engineers, 1991. http://dx.doi.org/10.1115/cie1991-0132.
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Abstract Traditional manual designing of bicycles often relies on prototype building and testing and since structural deficiencies often are not obvious until a prototype fails, several build-and-test iterations are usually required before a satisfactory design is obtained. Also, the final design may be less than optimal because of quick fixes inserted at the last minute. However, by utilizing computer-aided design, better bicycles can be designed at smaller investments of time and money. The development and utilization of a DI-3000 based (graphics subroutines developed by Precision Visual), user-friendly, self contained computer aided design package for the analysis and design of bicycle frames and forks are presented. The software, written in Fortran 77 and executable on most passive and active graphics devices, creates the necessary analysis input files for the ANSYS finite element program (developed and marketed by Swanson Analysis System Inc.). These pre and post processing files in conjunction with the ANSYS program are used to determine deflections and stress components. The graphics user interface module of the software allows users to enter bicycle geometry, loading and other pertinent data quickly and efficiently. Tubing configuration and specifications are selected from a data base through the use of cursor-controlled menus. The loading menu presents users with seven different types of realistic and self-consistent loading conditions from which to choose. Computer graphics is also used extensively wherever appropriate to enhance user-computer interaction. Contrasting color and text size are used to explain pictorially as well as visually unfamiliar terminology and to clarify vague sign or orientation conventions, thus, leading to more accurate input. While this package has been designed for instructional purposes, it can also be used by design engineers involved in the design of bicycles to facilitate the creation of ANSYS pre and post processing files.
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Jiang, Wei, Qi Shan, Huaisheng Wang, Dongli Zhang, and Mingxiang Wang. "Degradation of flexible LTPS TFTs under repetitive bending stress." In 2018 9th International Conference on Computer Aided Design for Thin-Film Transistors (CAD-TFT). IEEE, 2018. http://dx.doi.org/10.1109/cad-tft.2018.8608098.
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Lee, Cheng-Chun, G. Z. Cao, and I. Y. Shen. "Actuation Enhancement of PZT Thin-Film Membrane Actuators via Stress Relief Grooves." In ASME 2008 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/detc2008-49283.
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Lead Zirconate Titanate Oxide (PbZrxTi1−xO3 or PZT) is a piezoelectric material widely used as sensors and actuators. For microactuators, PZT often appears in the form of thin films to maintain proper aspect ratios. A common design is PZT membrane microactuator, whose actuation portion takes a form of a thin diaphragm driven by a PZT thin film. To maximize actuation displacements, finite element analyses are conducted to identify critical design parameters of the PZT film. In the simulation, a constant driving electric field is maintained and boundary conditions of the PZT film are varied. The finite element analyses lead to two important results. First, the actuator displacement increases as the PZT film thickness increases, but saturates at a critical PZT film thickness. Second, when stress relief grooves are introduced and the PZT film surrounding the membrane area is removed, the actuator displacement increases substantially by at least a factor of 5.
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Lu, Yiping, and Srinath V. Ekkad. "Understanding the Effect of Trenching on Film Cooling." In ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference collocated with the ASME 2007 InterPACK Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ht2007-32598.
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Recently, there has been a strong focus on film cooling holes embedded in trenches. In this study, film cooling predictions are used to understand the mechanisms of the jets that exit these trenched holes. The present work employs RSM (Reynolds stress transport models) for simulation of turbulent flows in film cooling and the simulation was run using FLUENT computer code. Comparisons are made with experimental data for the film effectiveness distributions. Results show that the film cooling jet exiting the trenched hole shows more two-dimensional flow than the typical cylindrical holes. The jet appears to remain closer to the surface providing more coverage to the surface.
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Lee, Jiseob, Suhui Lee, Duk Young Jeong, and Jin Jang. "Highly stable self-aligned coplanar a-IGZO TFTs under high temperature stress." In 2018 9th International Conference on Computer Aided Design for Thin-Film Transistors (CAD-TFT). IEEE, 2018. http://dx.doi.org/10.1109/cad-tft.2018.8608117.
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Zhou, Fang, Hassan Mahfuz, Gabriel M. Alsenas, and Howard P. Hanson. "Design and Analysis of Composite Ocean Current Turbine Blades Using NREL Codes." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-86373.
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Ocean current energy is at an early stage of development — a vital component in that is the design and analysis of turbine blades that would be used to generate the power. The ocean current turbine (OCT) is similar in function to wind turbines, capturing energy through the processes of hydrodynamic, rather than aerodynamic, lift or drag. OCT operates on many of the same principles as wind turbines and share similar design philosophies. NREL (National Renewable Energy Laboratory) has extensively investigated the design of wind turbine blades over the years and many codes have been developed. It is meaningful and prudent to take advantage of those codes and use them in the design of OCT blades. Currently available codes such as FoilCheck, PreComp, BModes, AeroDyn, FAST, etc. provides an excellent dynamic analysis of hollow composite wind turbine blades. Since OCT blades have PVC foam as core materials inside the skin, NREL codes could not be used directly. These core materials for the blade were necessary to fulfill the buoyancy requirement at ocean depth. A set of methods was therefore developed to design and analyze OCT blades where most of NREL codes could be utilized. The methods are as follows: DesignFOIL was first used to generate hydrofoil geometry (coordinates), and lift and drag coefficients for selected blade sections. FoilCheck was then used to calculate hydrofoil data for the entire range of ±180°. FoilCheck output files were later used as input for AeroDyn. In the next step, PreComp computed the section properties for the hollow composite OCT blade. Section properties of the core material such as extensional stiffness, flexural rigidity, and torsional rigidity were calculated separately and added to the properties computed by PreComp. Mode shapes and frequencies of OCT blades were computed using BModes. AeroDyn calculated the hydrodynamic lift and drag forces for the hydrofoil sections along the blade. In AeroDyn input file, kinematic viscosity, density and velocity were set to the values of seawater @ 1.05×10−6 m2/sec, 1025 kg/m3, and 1.7 m/s, respectively. Finally, FAST was used to obtain the dynamic response of three-bladed, conventional, horizontal-axis OCT. However, this analysis did not provide any stress calculations. In order to perform stress analysis, NuMAD code developed by Sandia National Laboratory was incorporated in the method. This allowed us to create ANSYS input files. Loads calculated by AeroDyn were then transported to ANSYS and a complete stress analysis was performed. Critical regions of stress concentration were identified — opening up an opportunity for materials failure and fatigue analysis. In summary, coupling of NREL codes, NuMAD, and ANSYS revealed a path way to achieve comprehensive design and analyses of OCT blades.
Reports on the topic "Struts (Computer file)"
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Patel, Reena. Complex network analysis for early detection of failure mechanisms in resilient bio-structures. Engineer Research and Development Center (U.S.), 2021. http://dx.doi.org/10.21079/11681/41042.
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Bio-structures owe their remarkable mechanical properties to their hierarchical geometrical arrangement as well as heterogeneous material properties. This dissertation presents an integrated, interdisciplinary approach that employs computational mechanics combined with flow network analysis to gain fundamental insights into the failure mechanisms of high performance, light-weight, structured composites by examining the stress flow patterns formed in the nascent stages of loading for the rostrum of the paddlefish. The data required for the flow network analysis was generated from the finite element analysis of the rostrum. The flow network was weighted based on the parameter of interest, which is stress in the current study. The changing kinematics of the structural system was provided as input to the algorithm that computes the minimum-cut of the flow network. The proposed approach was verified using two classical problems three- and four-point bending of a simply-supported concrete beam. The current study also addresses the methodology used to prepare data in an appropriate format for a seamless transition from finite element binary database files to the abstract mathematical domain needed for the network flow analysis. A robust, platform-independent procedure was developed that efficiently handles the large datasets produced by the finite element simulations. Results from computational mechanics using Abaqus and complex network analysis are presented.
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Heymsfield, Ernie, and Jeb Tingle. State of the practice in pavement structural design/analysis codes relevant to airfield pavement design. Engineer Research and Development Center (U.S.), 2021. http://dx.doi.org/10.21079/11681/40542.
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An airfield pavement structure is designed to support aircraft live loads for a specified pavement design life. Computer codes are available to assist the engineer in designing an airfield pavement structure. Pavement structural design is generally a function of five criteria: the pavement structural configuration, materials, the applied loading, ambient conditions, and how pavement failure is defined. The two typical types of pavement structures, rigid and flexible, provide load support in fundamentally different ways and develop different stress distributions at the pavement – base interface. Airfield pavement structural design is unique due to the large concentrated dynamic loads that a pavement structure endures to support aircraft movements. Aircraft live loads that accompany aircraft movements are characterized in terms of the load magnitude, load area (tire-pavement contact surface), aircraft speed, movement frequency, landing gear configuration, and wheel coverage. The typical methods used for pavement structural design can be categorized into three approaches: empirical methods, analytical (closed-form) solutions, and numerical (finite element analysis) approaches. This article examines computational approaches used for airfield pavement structural design to summarize the state-of-the-practice and to identify opportunities for future advancements. United States and non-U.S. airfield pavement structural codes are reviewed in this article considering their computational methodology and intrinsic qualities.
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Shani, Uri, Lynn Dudley, Alon Ben-Gal, Menachem Moshelion, and Yajun Wu. Root Conductance, Root-soil Interface Water Potential, Water and Ion Channel Function, and Tissue Expression Profile as Affected by Environmental Conditions. United States Department of Agriculture, 2007. http://dx.doi.org/10.32747/2007.7592119.bard.
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Constraints on water resources and the environment necessitate more efficient use of water. The key to efficient management is an understanding of the physical and physiological processes occurring in the soil-root hydraulic continuum.While both soil and plant leaf water potentials are well understood, modeled and measured, the root-soil interface where actual uptake processes occur has not been sufficiently studied. The water potential at the root-soil interface (yᵣₒₒₜ), determined by environmental conditions and by soil and plant hydraulic properties, serves as a boundary value in soil and plant uptake equations. In this work, we propose to 1) refine and implement a method for measuring yᵣₒₒₜ; 2) measure yᵣₒₒₜ, water uptake and root hydraulic conductivity for wild type tomato and Arabidopsis under varied q, K⁺, Na⁺ and Cl⁻ levels in the root zone; 3) verify the role of MIPs and ion channels response to q, K⁺ and Na⁺ levels in Arabidopsis and tomato; 4) study the relationships between yᵣₒₒₜ and root hydraulic conductivity for various crops representing important botanical and agricultural species, under conditions of varying soil types, water contents and salinity; and 5) integrate the above to water uptake term(s) to be implemented in models. We have made significant progress toward establishing the efficacy of the emittensiometer and on the molecular biology studies. We have added an additional method for measuring ψᵣₒₒₜ. High-frequency water application through the water source while the plant emerges and becomes established encourages roots to develop towards and into the water source itself. The yᵣₒₒₜ and yₛₒᵢₗ values reflected wetting and drying processes in the rhizosphere and in the bulk soil. Thus, yᵣₒₒₜ can be manipulated by changing irrigation level and frequency. An important and surprising finding resulting from the current research is the obtained yᵣₒₒₜ value. The yᵣₒₒₜ measured using the three different methods: emittensiometer, micro-tensiometer and MRI imaging in both sunflower, tomato and corn plants fell in the same range and were higher by one to three orders of magnitude from the values of -600 to -15,000 cm suggested in the literature. We have added additional information on the regulation of aquaporins and transporters at the transcript and protein levels, particularly under stress. Our preliminary results show that overexpression of one aquaporin gene in tomato dramatically increases its transpiration level (unpublished results). Based on this information, we started screening mutants for other aquaporin genes. During the feasibility testing year, we identified homozygous mutants for eight aquaporin genes, including six mutants for five of the PIP2 genes. Including the homozygous mutants directly available at the ABRC seed stock center, we now have mutants for 11 of the 19 aquaporin genes of interest. Currently, we are screening mutants for other aquaporin genes and ion transporter genes. Understanding plant water uptake under stress is essential for the further advancement of molecular plant stress tolerance work as well as for efficient use of water in agriculture. Virtually all of Israel’s agriculture and about 40% of US agriculture is made possible by irrigation. Both countries face increasing risk of water shortages as urban requirements grow. Both countries will have to find methods of protecting the soil resource while conserving water resources—goals that appear to be in direct conflict. The climate-plant-soil-water system is nonlinear with many feedback mechanisms. Conceptual plant uptake and growth models and mechanism-based computer-simulation models will be valuable tools in developing irrigation regimes and methods that maximize the efficiency of agricultural water. This proposal will contribute to the development of these models by providing critical information on water extraction by the plant that will result in improved predictions of both water requirements and crop yields. Plant water use and plant response to environmental conditions cannot possibly be understood by using the tools and language of a single scientific discipline. This proposal links the disciplines of soil physics and soil physical chemistry with plant physiology and molecular biology in order to correctly treat and understand the soil-plant interface in terms of integrated comprehension. Results from the project will contribute to a mechanistic understanding of the SPAC and will inspire continued multidisciplinary research.