6,430 research outputs found
Advanced composite airframe program: Today's technology
The Advanced Composite Airframe Program (ACAP) was undertaken to demonstrate the advantages of the application of advanced composite materials and structural design concepts to the airframe structure on helicopters designed to stringent military requirements. The primary goals of the program were the reduction of airframe production costs and airframe weight by 17 and 22 percent respectively. The ACAP effort consisted of a preliminary design phase, detail design, and design support testing, full-scale fabrication, laboratory testing, and a ground/flight test demonstration. Since the completion of the flight test demonstration programs follow-on efforts were initiated to more fully evaluate a variety of military characteristics of the composite airframe structures developed under the original ACAP advanced development contracts. An overview of the ACAP program is provided and some of the design features, design support testing, manufacturing approaches, and the results of the flight test evaluation, as well as, an overview of Militarization Test and Evaluation efforts are described
Solving the Bermuda Mystery: an Island that Tells a Story of a New Way to Form Volcanoes
Bermuda’s explosive past has changed how geologists think about the processes that make volcanoes. The chemical composition of the lavas analyzed in this study indicate that Bermuda ‘tapped’ a geologically young, volatile rich layer in the mantle, unlike anything previously known
Fracture behaviour of single crystal silicon microstructures
The fracture behaviour of single crystal silicon (SCSi) microstructures is analysed based on microme-chanical torsional and tensile experiments. The uniaxial testpieces are characterised by the presence of sharp not-ches at the gauge length extremities. The critical loading conditions are reproduced in a finite element model in order to identify the analogies of the failure conditions in tension and torsion. The stress field in the vicinity of the notch tip (were cracks originate) is analyzed, and fracture mechanics parameters are determined. In the finite element model a crack, reproducing the failure process observed in the experiments, is included. The crack area is incrementally increased and the energy release rate for the critical loading conditions in tension and torsion is calculated. Based on these results a failure criterion is formulated along with a procedure for the mechanical integrity analysis of SCSi microstructures of arbitrary shape and loading condition
Aspectos da fenologia reprodutiva de Maytenus ilicifolia Mart. Ex Reiss. (Celastraceae) em uma Unidade de Conservação na formação Floresta Ombrófila Mista.
Caracterização da paisagem e zoneamento ambiental conceitual da Floresta Nacional de Irati.
Multimedia digital solutions from image and range based models for ancient landscapes communication
The paper presents the results of an interdisciplinary project which aimed at the dissemination of some archaeological remains producing multimedia contents from multisensor surveyed 3D data. The scope of this application pertained to the use of 3D detailed models as a base for some video-installations with the aim to arouse the visitors’ emotions and improve their museum experience. This work has been applied to the Arch of Augustus located in the archaeological site of Susa and to two ancient Roman marble statues, found in the city of Susa in 1802 and now displayed in the Archaeological Museum of Turin. The Arch of Augustus is in a remarkable state of conservation. Its decorated frieze tells about the peace between the Romans and the Celts but it is difficult to see for visitors at the ground level. A multisensor 3D survey, by means of laser scanning technique and photogrammetric method, made it possible to process a detailed 3D textured model, which provided the base for the creation of a life-size model to be placed in the Museum of Susa on which a designed didactic video map is projected, which explains the meaning of the frieze. The two statues, known as ‘busti loricati di Susa’ and representing two Roman emperors, were surveyed with a photogrammetric method with the aim of processing two 3D models representing the statues before the 19th century restoration, on the basis of archival sources. These models provided the base for a video installation for the museum which simulates a holographic projection and explains the different armour parts highlighting them in sequence. Nowadays modern metric survey technologies allow us to collect and process very detailed 3D models able to satisfy a wide variety of applications field, from specialized representation to didactic final uses in museums exhibitions
Could time detect a faking-good attitude? A study with the MMPI-2-RF
Background and Purpose: Research on the relationship between response latency (RL) and faking in self-administered testing scenarios have generated contradictory findings. We explored this relationship further, aiming to add further insight into the reliability of self-report measures. We compared RLs and T-scores on the MMPI-2-RF (validity and restructured clinical [RC] scales) in four experimental groups. Our hypotheses were that: the Fake-Good Speeded group would obtain a different completion time; show higher RLs than the Honesty Speeded Group in the validity scales; show higher T-Scores in the L-r and K-r scales and lower T-scores in the F-r and RC scales; and show higher levels of tension and fatigue. Finally, the impact of the speeded condition in malingering was assessed. Materials and Methods: The sample was comprised of 135 subjects (M = 26.64; SD = 1.88 years old), all of whom were graduates (having completed at least 17 years of instruction), male, and Caucasian. Subjects were randomly assigned to four groups: Honesty Speeded, Fake-Good Speeded, Honesty Un-Speeded, and Fake-Good Un-Speeded. A software version of the MMPI-2-RF and Visual Analog Scale (VAS) were administered. To test the hypotheses, MANOVAs and binomial logistic regressions were run. Results: Significant differences were found between the four groups, and particularly between the Honest and Fake-Good groups in terms of test completion time and the L-r and K-r scales. The speeded condition increased T-scores in the L-r and K-r scales but decreased T-scores in some of the RC scales. The Fake groups also scored higher on the VAS Tension subscale. Completion times for the first and second parts of the MMPI-2-RF and T-scores for the K-r scale seemed to predict malingering. Conclusion: The speeded condition seemed to bring out the malingerers. Limitations include the sample size and gender bias
Fenologia reprodutiva de Maytenus ilicifolia (Celastraceae) na Floresta Nacional de Irati, Paraná, Brasil.
(Reproductive phenology of Maytenus ilicifolia (Celastraceae) in the Irati National Forest, Paraná, Brazil). The present study investigates the reproductive phenology of a natural population of Maytenus ilicifolia Mart. ex Reissek from the Mixed Ombrophylous Forest (Araucaria Forest). The phenological study was carried out from April 2003 to March 2005, on 78 adult trees. The intensity of phenological events was estimated based on the scale of Fournier. The population showed seasonal behavior. A significant correlation was observed between temperature, day length and flowering. Two floral types were identified, one pistillate and the other staminate, and together with the phenology patterns results a dioecious characteristic for the species is suggested
The Tropical Transition of the October 1996 Medicane in the Western Mediterranean Sea: A Warm Seclusion Event
The processes leading to the tropical transition of the October 1996 medicane in the western Mediterranean are investigated on the basis of a 50-member ensemble of regional climate model (RCM) simulations. By comparing the composites of transitioning and nontransitioning cyclones it is shown that standard extratropical dynamics are responsible for the cyclogenesis and that the transition results from a warm seclusion process. As the initial thermal asymmetries and vertical tilt of the cyclones are reduced, a warm core forms in
the lower troposphere. It is demonstrated that in the transitioning cyclones, the upper-tropospheric warm core is also a result of the seclusion process. Conversely, the warm core remains confined below 600 hPa in the nontransitioning systems. In the baroclinic stage, the transitioning cyclones are characterized by larger vertical wind shear and intensification rates. The resulting stronger low-level circulation in turn is responsible for significantly larger latent and sensible heat fluxes throughout the seclusion process
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