Development of 3D Compression Molded Composite Primary Structure

The work accomplished by the Black Gold team improved upon the carbon fiber compression molding research and information available on the Cal Poly San Luis Obispo campus. The team used the rear suspension rocker arm off a Ventana Alpino mountain bike as a design goal for this project. This research and body of work includes the methods used to design a compression molded part for complex part loading and shape. This extends to the process of choosing an appropriate layup process, in addition to benefits and drawbacks of the use of chopped fibers in compression molding. The research includes the process and information required to build aluminum molds for compression molded parts of complex shape; manufacturing techniques, and suggestions for the use of compression molding carbon fiber. Finally, data is presented which compares the final compression molding results under ultimate and relative stiffness testing to a comparable part made from aluminum. Ultimately, the team found that compression molding proved to be a potential manufacturing alternative. The rocker arms produced by the team were able to withstand a load of up to 800lbs; meeting the teams initial design criteria before experiencing localized fractures. With future iteration, and more focus on design for loading, the process could yield parts which could carry much higher loads. In addition, the use of chopped fiber around the bearings regions was a success, ultimately showing that a combination of chopped and cloth fiber was a useful load carrying combination. Further research in these processes would definitively improve upon the results obtained by the team, and as information regarding compression molding increases the team expects its use to become more popular

G-Sense: a scalable architecture for global sensing and monitoring

The pervasiveness of cellular phones combined with Internet connectivity, GPS embedded chips, location information, and integrated sensors provide an excellent platform to collect data about the individual and its surrounding environment. As a result, new applications have recently appeared to address large-scale societal problems as well as improve the quality of life of the individual. However, these new applications, recently called location-based services, participatory sensing, and human-centric sensing, bring many new challenges, one of them being the management of the huge amount of traffic (data) they generate. This article presents G-Sense, for Global-Sense, an architecture that integrates mobile and static wireless sensor networks in support of location-based services, participatory sensing, and human-centric sensing applications. G-Sense includes specific mechanisms to control the amount of data generated by these applications while meeting the application requirements. Furthermore, it creates a network of servers organized in a peer-to-peer architecture to address scalability and reliability issues. An example prototype application is presented along with some basic results and open research issues

A location-aware framework for intelligent real-time mobile applications

The Location-Aware Information Systems Client (LAISYC) supports intelligent, real-time, mobile applications for GPS-enabled mobile phones by dynamically adjusting platform parameters for application performance while conserving device resources such as battery life

A How-To Guide for Student Generated Video

The type of assessment used by the instructor is a major consideration that must be taken into account when designing a third level course. The importance of assessment can be understood if one frames it not only as assessment of learning but also as assessment for learning. In this new framework, in addition to measuring students’ knowledge of the material, assessment can be thought of as a tool used for providing feedback, for defining academic standards, and for directing student learning (Harris, 2005). There is currently a movement calling for a shift away from traditional high-stakes assessment towards alternative assessment practices based on the increasingly diverse student population, constructivist learning theory, and the need for more authentic evaluations of student performance (Anderson, 1998). Within this trend, it is important to consider the potential of technology. The use of student-generated videos as assessment tools can be one way to incorporate technology into the classroom when taking a blended learning approach. This can increase student motivation, improve attitudes and learning behaviors, and increase learning performance. Generating videos is a move from passive to active learning. This project aimed to produce a how-to guide for the creation of video assignments within a specific module. We intend this guide to serve as a resource for lectures to aid the students when using this innovative assessment method. The graphic nature of the resource makes it easy to follow and student-centred, especially when compared to existing resources which tend to be text-based and more difficult to follow. In addition, it is our hope that our guide can encourage uniformity, be reusable, and provide a clear process that students can follow when taking on video assessments

Integrating HIP and homogenisation heat treatment and its effect on the workability of a conventional peritectic TiAl alloy

The aim of this study was to understand how consolidation and homogenisation, as well as the possibility of integrating the two processes, influences the pre-compression microstructure and subsequent compression behaviour of an industry accepted, peritectic solidifying titanium aluminide ingot alloy; 45XD. This study differs from existing work with its emphasis on understanding the effect of integrating consolidation and homogenisation on workability, as well as how these processes influence the pre-and postcompression microstructure individually. This was assessed by the material’s strain rate sensitivity in primary and secondary compression. The target microstructure was identified from the literature as being capable of a strain rate sensitivity of ≥0.3. The results presented here show that it is possible to integrate the consolidation and homogenisation stages, and this proved beneficial, namely achieving a high lamellar content and elementally homogeneous microstructure presented prior to compression. Subsequent deformation generated high values of dynamic recrystallisation fraction and globularisation returned upon primary compression, and the highest strain rate sensitivity at secondary compression, in comparison to material processed by the traditional approach. This is thought to be due to pressure and temperature during the integrated process reducing both segregation, seen through casting, and so the B2/β0 content compared to consolidated material. The integrated consolidation and homogenisation approach also prevented the grain growth seen in the traditional route; this is anticipated to be due to the two slow cooling stages involved in the traditional process rather than the effect of isostatic pressure

One Solution to the Mass Budget Problem for Planet Formation: Optically Thick Disks with Dust Scattering

Atacama Large Millimeter Array (ALMA) surveys have suggested that the dust in Class II disks may not be enough to explain the averaged solid mass in exoplanets, under the assumption that the mm disk continuum emission is optically thin. This optically thin assumption seems to be supported by recent Disk Substructures at High Angular Resolution Project (DSHARP) observations where the measured optical depths are mostly less than one. However, we point out that dust scattering can considerably reduce the emission from an optically thick region. If that scattering is ignored, an optically thick disk with scattering can be misidentified as an optically thin disk. Dust scattering in more inclined disks can reduce the intensity even further, making the disk look even fainter. The measured optical depth of ~0.6 in several DSHARP disks can be naturally explained by optically thick dust with an albedo of ~0.9 at 1.25 mm. Using the DSHARP opacity, this albedo corresponds to a dust population with the maximum grain size (s max) of 0.1–1 mm. For optically thick scattering disks, the measured spectral index α can be either larger or smaller than 2 depending on whether the dust albedo increases or decreases with wavelength. We describe how this optically thick scattering scenario could explain the observed scaling between submm continuum sizes and luminosities, and might help ease the tension between the dust size constraints from polarization and dust continuum measurements. We suggest that a significant amount of disk mass can be hidden from ALMA observations and longer wavelength observations (e.g., Very Large Array or Square Kilometre Array) are desired to probe the dust mass in disks

Improving forging outcomes of cast titanium aluminide alloy via cyclic induction heat treatment

The objective of this research was to improve the forging outcome of peritectic solidifying cast titanium aluminide (TiAl) 4822 alloy (Ti-48Al-2Nb-2Cr at.%) in hot isostatic pressed and homogenised (HH) condition using cyclic induction heat treatment (CHT). This study adds to research around CHT for TiAl alloys by applying industrially relevant induction heating to conduct five heating cycles at the single αphase temperatures (1370 °C) necessary for grain refinement. Two cooling rates were explored in each cycle, air cooling (ACCHT) and controlled furnace-like cooling (FCCHT), without returning to room temperature. Samples were assessed at each stage in terms of their morphologies, lamellar grain size and content, as well as phase and dynamic recrystallised fraction, and subsequent primary and secondary compression behaviour with uniaxial isothermal compression. The FCCHT process resulted in a homogeneously refined fully lamellar microstructure, and ACCHT, in a heterogeneous microstructure consisting of lamellar and feathery γ (γf) at differing fractions across the piece, depending on the cooling rate compared with HH. The results show that CHT improved forging outcomes for both compression stages investigated, resulting in uniform compression samples with higher volumes of dynamic recrystallised material compared with the instability seen with the compression of HH material