Performance analysis of cutting graphite-epoxy composite using a 90,000 PSI abrasive waterjet

Graphite-epoxy composites are being widely used in many aerospace and structural applications because of their properties: which include lighter weight, higher strength to weight ratio and a greater flexibility in design. However, the inherent anisotropy of these composites makes it difficult to machine them using conventional methods. To overcome the major issues that develop with conventional machining such as fiber pull out, delamination, heat generation and high tooling costs, an effort is herein made to study abrasive waterjet machining of composites. An abrasive waterjet is used to cut 1 thick graphite epoxy composites based on baseline data obtained from the cutting of 1/4 thick material. The objective of this project is to study the surface roughness of the cut surface with a focus on demonstrating the benefits of using higher pressures for cutting composites. The effects of major cutting parameters: jet pressure, traverse speed, abrasive feed rate and cutting head size are studied at different levels. Statistical analysis of the experimental data provides an understanding of the effect of the process parameters on surface roughness. Additionally, the effect of these parameters on the taper angle of the cut is studied. The data is analyzed to obtain a set of process parameters that optimize the cutting of 1 thick graphite-epoxy composite. The statistical analysis is used to validate the experimental data. Costs involved in the cutting process are investigated in term of abrasive consumed to better understand and illustrate the practical benefits of using higher pressures. It is demonstrated that, as pressure increased, ultra-high pressure waterjets produced a better surface quality at a faster traverse rate with lower costs --Abstract, page iii

Low Temperature Polymeric Precursor Derived Zinc Oxide Thin Films

Zinc oxide (ZnO) is a versatile environmentally benign II-VI direct wide band gap semiconductor with several technologically plausible applications such as transparent conducting oxide in flat panel and flexible displays. Hence, ZnO thin films have to be processed below the glass transition temperatures of polymeric substrates used in flexible displays. ZnO thin films were synthesized via aqueous polymeric precursor process by different metallic salt routes using ethylene glycol, glycerol, citric acid, and ethylene diamine tetraacetic acid (EDTA) as chelating agents. ZnO thin films, derived from ethylene glycol based polymeric precursor, exhibit flower-like morphology whereas thin films derived of other precursors illustrate crack free nanocrystalline films. ZnO thin films on sapphire substrates show an increase in preferential orientation along the (002) plane with increase in annealing temperature. The polymeric precursors have also been used in fabricating maskless patterned ZnO thin films in a single step using the commercial Maskless Mesoscale Materials Deposition system

ECO-CHIP: Estimation of Carbon Footprint of Chiplet-based Architectures for Sustainable VLSI

Decades of progress in energy-efficient and low-power design have successfully reduced the operational carbon footprint in the semiconductor industry. However, this has led to an increase in embodied emissions, encompassing carbon emissions arising from design, manufacturing, packaging, and other infrastructural activities. While existing research has developed tools to analyze embodied carbon at the computer architecture level for traditional monolithic systems, these tools do not apply to near-mainstream heterogeneous integration (HI) technologies. HI systems offer significant potential for sustainable computing by minimizing carbon emissions through two key strategies: ``reducing" computation by reusing pre-designed chiplet IP blocks and adopting hierarchical approaches to system design. The reuse of chiplets across multiple designs, even spanning multiple generations of integrated circuits (ICs), can substantially reduce embodied carbon emissions throughout the operational lifespan. This paper introduces a carbon analysis tool specifically designed to assess the potential of HI systems in facilitating greener VLSI system design and manufacturing approaches. The tool takes into account scaling, chiplet and packaging yields, design complexity, and even carbon overheads associated with advanced packaging techniques employed in heterogeneous systems. Experimental results demonstrate that HI can achieve a reduction of embodied carbon emissions up to 70\% compared to traditional large monolithic systems. These findings suggest that HI can pave the way for sustainable computing practices, contributing to a more environmentally conscious semiconductor industry.Comment: Under review at HPCA2

Experimental investigation of fiber-reininforced polymer composite bridge deck panel in cold regions

Thesis (M.S.) University of Alaska Fairbanks, 2005To build highway bridges in cold regions like Alaska, cast-in-place concrete has been found to be difficult and expensive, especially in winter seasons. Decked Bulb-Tee bridge members can be heavy and the deck cannot be replaced. On the other hand, fiber-reinforced plastic (FRP) composite materials offer a great opportunity in this area. The primary technical barrier to the use of composite materials in infrastructure applications is lack of data on environmental durability. The present study presents experimental load and strain results of a FRP composite panel that was subjected to cold temperatures. The FRP panel consists of an upper and a bottom laminate tied by a honeycomb core, which was produced by sequentially bonding a flat sheet to a corrugated sheet. Specifically, the objective of this research was to understand the effects of low temperature and low-temperature thermal cycling on the performance of FRP composite bridge deck panels in cold regions. This was achieved by analyzing static tests and results for a FRP deck panel. The research results reported herein showed an increase in stiffness as temperature was lowered up to a certain point, and a reverse trend at a further lower temperature

Building Security Perimeters to Protect Network Systems Against Cyber Threats [Future Directions]

© 2012 IEEE. Due to the wide variety of devices used in computer network systems, cybersecurity plays a major role in securing and improving the performance of the network or system. Although cybersecurity has received a large amount of global interest in recent years, it remains an open research space. Current security solutions in network-based cyberspace provide an open door to attackers by communicating first before authentication, thereby leaving a black hole for an attacker to enter the system before authentication. This article provides an overview of cyberthreats, traditional security solutions, and the advanced security model to overcome current security drawbacks

Collaborative Edge Computing for Smart Villages

The term "collaborative edge computing"is new. Edge computing is a crucial technology for thedeployment of smart villages. Due to edge devices' resource constraint features, collaborative computing is a key challenge to borrow computational resources to meet demands of smart villages. This article gives first-hand experiences on collaborative edge computing and its use for smart villages

A Computing Perspective of Quantum Cryptography [Energy and Security]

© 2012 IEEE. In the continuous evolution of the computer age, the next big step in security is being achieved by embracing quantum cryptography. As the unit of information shifts from the currently used bit to the quantum bit (qubit), a new realm of untapped features is offered that can be used to ensure the confidentiality of the information being shared among participants. This system confidentiality is ensured by the use of a quantum channel for exchanging secret keys, which are then used to encrypt the data being shared. The system is a combination of cryptography and quantum computing that is aided by the laws of physics

ECO-CHIP: Estimation of Carbon Footprint of Chiplet-based Architectures for Sustainable VLSI: HPCA 2024 Artifact Evaluation

<p>The paper introduces ECO-CHIP, a framework for measuring the carbon footprint (CFP) of a heterogeneous system across its lifespan. This artifact is released on Zenodo and contains two parts. The first is ECO-CHIP submodule from GitHub, and the second is a folder that consists of the experiments performed in this paper using ECO-CHIP. The minimal hardware requirements are any single-core CPU, and the software requirements are Python 3.9 with pip 22.04.</p&gt