400 resultados para Lightweight


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Recent advances in technology have produced a significant increase in the availability of free sensor data over the Internet. With affordable weather monitoring stations now available to individual meteorology enthusiasts a reservoir of real time data such as temperature, rainfall and wind speed can now be obtained for most of the United States and Europe. Despite the abundance of available data, obtaining useable information about the weather in your local neighbourhood requires complex processing that poses several challenges. This paper discusses a collection of technologies and applications that harvest, refine and process this data, culminating in information that has been tailored toward the user. In this case we are particularly interested in allowing a user to make direct queries about the weather at any location, even when this is not directly instrumented, using interpolation methods. We also consider how the uncertainty that the interpolation introduces can then be communicated to the user of the system, using UncertML, a developing standard for uncertainty representation.

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The ability to use Software Defined Radio (SDR) in the civilian mobile applications will make it possible for the next generation of mobile devices to handle multi-standard personal wireless devices and ubiquitous wireless devices. The original military standard created many beneficial characteristics for SDR, but resulted in a number of disadvantages as well. Many challenges in commercializing SDR are still the subject of interest in the software radio research community. Four main issues that have been already addressed are performance, size, weight, and power. ^ This investigation presents an in-depth study of SDR inter-components communications in terms of total link delay related to the number of components and packet sizes in systems based on Software Communication Architecture (SCA). The study is based on the investigation of the controlled environment platform. Results suggest that the total link delay does not linearly increase with the number of components and the packet sizes. The closed form expression of the delay was modeled using a logistic function in terms of the number of components and packet sizes. The model performed well when the number of components was large. ^ Based upon the mobility applications, energy consumption has become one of the most crucial limitations. SDR will not only provide flexibility of multi-protocol support, but this desirable feature will also bring a choice of mobile protocols. Having such a variety of choices available creates a problem in the selection of the most appropriate protocol to transmit. An investigation in a real-time algorithm to optimize energy efficiency was also performed. Communication energy models were used including switching estimation to develop a waveform selection algorithm. Simulations were performed to validate the concept.^

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This paper introduces the LiDAR compass, a bounded and extremely lightweight heading estimation technique that combines a two-dimensional laser scanner and axis maps, which represent the orientations of flat surfaces in the environment. Although suitable for a variety of indoor and outdoor environments, the LiDAR compass is especially useful for embedded and real-time applications requiring low computational overhead. For example, when combined with a sensor that can measure translation (e.g., wheel encoders) the LiDAR compass can be used to yield accurate, lightweight, and very easily implementable localization that requires no prior mapping phase. The utility of using the LiDAR compass as part of a localization algorithm was tested on a widely-available open-source data set, an indoor environment, and a larger-scale outdoor environment. In all cases, it was shown that the growth in heading error was bounded, which significantly reduced the position error to less than 1% of the distance travelled.

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Internal curing is a relatively new technique being used to promote hydration of Portland cement concretes. The fundamental concept is to provide reservoirs of water within the matrix such that the water does not increase the initial water/cementitious materials ratio to the mixture, but is available to help continue hydration once the system starts to dry out. The reservoirs used in the US are typically in the form of lightweight fine aggregate (LWFA) that is saturated prior to batching. Considerable work has been conducted both in the laboratory and in the field to confirm that this approach is fundamentally sound and yet practical for construction purposes. A number of bridge decks have been successfully constructed around the US, including one in Iowa in 2013. It is reported that inclusion of about 20% to 30% LWFA will not only improve strength development and potential durability, but, more importantly, will significantly reduce shrinking, thus reducing cracking risk. The aim of this work was to investigate the feasibility of such an approach in a bridge deck.

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Presented in this report is an investigation of the use of "sand-lightweight" concrete in prestressed concrete structures. The sand-lightweight concrete consists of 100% sand substitution for fines, along with Idealite coarse and medium lightweight aggregate and Type I Portland Cement.

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In February of 1968 a cooperative research project by the Iowa State Highway Commission (Project No. HR-136) and the University of Iowa, Iowa City, Iowa was initiated in order to determine experimentally the creep and shrinkage characteristics of lightweight-aggregate concrete used in the State of Iowa. This report is concerned with Phase 1 of the Project as described in the Prospectus for the project submitted in November of 1967: "The State Highway Commission is planning to conduct pilot studies in prestressed-lightweight structures fabricated with materials that are proposed for use in bridge structures in the near future. Thus, Phase will have as its immediate objective, investigating the materials to be used in the above mentioned pilot studies.” (1) The work described in this report was also carried out in conjunction with a second cooperative project: "Time-Dependent Camber and Deflection of Non-Composite and Composite Lightweight-Prestressed Concrete Beams" (Project No. HR-137).

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Thesis (Master's)--University of Washington, 2016-08

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This work was motivated by the extensive research on lithium solid state materials, which have attracted increasing interest for potential applications in hydrogen storage and/or lithium ion batteries due to their extraordinary properties. In this thesis, LiBH4-derived materials, LiInBr4 and complex phases based on lithium ammonia borane with potential use as solid state electrolytes were successfully synthesised and characterised.

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This study investigated the physical characteristics of lightweight concrete produced using waste materials as coarse aggregate. The study was inspired by the author’s Peace Corps service in Kilwa, Tanzania. Coconut shell, sisal fiber, and PET plastic were chosen as the test waste products due to their abundance in the area. Two mixes were produced for each waste product and the mix proportions designed for resulting compressive strengths of 3000 and 5000 psi. The proportions were selected based on guidelines for lightweight concrete from the American Concrete Institute. In preparation for mixing, coconut shells were crushed into aggregate no larger than 3/4 inch, sisal fiber was cut into pieces no longer than 3/8 inch, and PET plastic was shredded into 1/4 inch-wide strips no longer than 6 inches. Replicate samples were mixed and then cured for 28 days before they were tested for compressive strength, unit weight, and absorption. The resulting data were compared to ASTM Standards for lightweight concrete masonry units to determine their adequacy. Based on these results, there is potential for coconut shell to be used as coarse aggregate in lightweight concrete. Sisal fiber was unsuccessful in producing the appropriate compressive strength. However, the reduction in spalling of the hardened concrete and the induction of air in the mixes incorporating sisal fiber suggests that it has the potential to improve other characteristics of lightweight concrete. Concrete mixes using PET plastic as aggregate resulted in adequate compressive strengths, but were too dense to be considered ‘lightweight’ concrete. With some adjustments to slightly decrease absorption and unit weight, the PET plastic concrete mixes could be classified as medium weight concrete and, therefore, achieve many of the same benefits as would be seen with lightweight concrete.

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The ability to use Software Defined Radio (SDR) in the civilian mobile applications will make it possible for the next generation of mobile devices to handle multi-standard personal wireless devices and ubiquitous wireless devices. The original military standard created many beneficial characteristics for SDR, but resulted in a number of disadvantages as well. Many challenges in commercializing SDR are still the subject of interest in the software radio research community. Four main issues that have been already addressed are performance, size, weight, and power. This investigation presents an in-depth study of SDR inter-components communications in terms of total link delay related to the number of components and packet sizes in systems based on Software Communication Architecture (SCA). The study is based on the investigation of the controlled environment platform. Results suggest that the total link delay does not linearly increase with the number of components and the packet sizes. The closed form expression of the delay was modeled using a logistic function in terms of the number of components and packet sizes. The model performed well when the number of components was large. Based upon the mobility applications, energy consumption has become one of the most crucial limitations. SDR will not only provide flexibility of multi-protocol support, but this desirable feature will also bring a choice of mobile protocols. Having such a variety of choices available creates a problem in the selection of the most appropriate protocol to transmit. An investigation in a real-time algorithm to optimize energy efficiency was also performed. Communication energy models were used including switching estimation to develop a waveform selection algorithm. Simulations were performed to validate the concept.

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The project aims to gather an understanding of additive manufacturing and other manufacturing 4.0 techniques with an eyesight for industrialization. First the internal material anisotropy of elements created with the most economically feasible FEM technique was established. An understanding of the main drivers for variability for AM was portrayed, with the focus on achieving material internal isotropy. Subsequently, a technique for deposition parameter optimization was presented, further procedure testing was performed following other polymeric materials and composites. A replicability assessment by means of the use of technology 4.0 was proposed, and subsequent industry findings gathered the ultimate need of developing a process that demonstrate how to re-engineer designs in order to show the best results with AM processing. The latest study aims to apply the Industrial Design and Structure Method (IDES) and applying all the knowledge previously stacked into fully reengineer a product with focus of applying tools from 4.0 era, from product feasibility studies, until CAE – FEM analysis and CAM – DfAM. These results would help in making AM and FDM processes a viable option to be combined with composites technologies to achieve a reliable, cost-effective manufacturing method that could also be used for mass market, industry applications.

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Gaze estimation has gained interest in recent years for being an important cue to obtain information about the internal cognitive state of humans. Regardless of whether it is the 3D gaze vector or the point of gaze (PoG), gaze estimation has been applied in various fields, such as: human robot interaction, augmented reality, medicine, aviation and automotive. In the latter field, as part of Advanced Driver-Assistance Systems (ADAS), it allows the development of cutting-edge systems capable of mitigating road accidents by monitoring driver distraction. Gaze estimation can be also used to enhance the driving experience, for instance, autonomous driving. It also can improve comfort with augmented reality components capable of being commanded by the driver's eyes. Although, several high-performance real-time inference works already exist, just a few are capable of working with only a RGB camera on computationally constrained devices, such as a microcontroller. This work aims to develop a low-cost, efficient and high-performance embedded system capable of estimating the driver's gaze using deep learning and a RGB camera. The proposed system has achieved near-SOTA performances with about 90% less memory footprint. The capabilities to generalize in unseen environments have been evaluated through a live demonstration, where high performance and near real-time inference were obtained using a webcam and a Raspberry Pi4.

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Objective. - The objective of this work was to verify if there was a difference in throwing speed performance between heavier and lighter weight categories in judo. Methods and subjects. - Sixteen (16) judoists 18 +/- 3 years old, eight considered in the lightweight category (< 66 kg) and eight considered in the heavyweight (> 73 kg) category, participated in the study after signing a term of informed consent. A force-velocity test was used to determine the anaerobic power, strength, and pedal speed for each subject. In addition, three trials of Nage-komi exercise, each comprised of a set of Osoto-gari (15s), Uchi-mata (15s) and Seoi-nage (15s) throws were performed by each subject to ascertain throwing speed. Throws within the sets were intersected by one period of three minutes passive rest, while the trials were separated by one period of 10 minutes passive rest. Heart rate and the greatest number of throws within each set were measured for three trials. One-way analysis of variance (Anova) was used to compare the number of throws between the two weight categories and a ""Student"" test when the difference was significant. A correlation was used to examine the link between the different parameters. Results. - The force-velocity test did not show a significant difference in pedal speed between the two categories. However, there was a significant difference between the two categories when throwing speed was measured by the number of throws (p < 0.05) executed during the Seoi-nage (p < 0.01) and Uchi-mata (p <0.05) techniques. There was however, no significant difference between the two categories in Osoto-gari technique. Conclusion. - The throwing speed of judoists represented by the number of throws is significantly different between the two categories. The lighter category has more speed than the heavier category using the arm technique (Seoi-nage), while the heavier category has more speed using the leg technique with half turn of the attacker`s body (Uchi-mata). As a result, throwing speed is related to the type of technique used and not weight category. (C) 2007 Elsevier Masson SAS. All rights reserved.