298 research outputs found

    Laser-based manufacturing routes for functionalizing surfaces

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    Robust functional surfaces are of a growing industrial interest for a range of optical, easy-to clean, anti-icing and non-fouling applications. At the same time, nature is a great source of inspiration for micro/nano-scale surface structures with tailored functional properties. There are a number of competing technologies for producing such structures but ultrashort laser processing is emerging as one of the most promising for fabricating bio-inspired surfaces. However, the technology has limitations and its capabilities have to be augmented to achieve the required high throughput in manufacturing products that incorporate functional surface topographies. Therefore, this research investigates a promising process chain that combines synergistically the capabilities of laser texturing with complementary surface engineering and replication technologies. Several large-area laser texturing techniques are investigated, namely Direct Laser Writing (DLW), Laser-Induced Periodic Surface Structures (LIPSS) and microlenses-induced Photonic Jet (PJ) texturing. The research advances the knowledge in laser-based surface functionalization and also in factors affecting the functional response and durability of laser structured surfaces

    Identification and Development of Novel Optics for Concentrator Photovoltaic Applications

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    Concentrating photovoltaic (CPV) systems are a key step in expanding the use of solar energy. Solar cells can operate at increased efficiencies under higher solar concentration and replacing solar cells with optical devices to capture light is an effective method of decreasing the cost of a system without compromising the amount of solar energy absorbed. CPV systems are however still in a stage of development where new designs, methods and materials are still being created in order to reach a low levelled cost of energy comparable to standard silicon based photovoltaic (PV) systems. This work outlines the different types of concentration photovoltaic systems, their various design advantages and limitations, and noticeable trends. Comparisons on materials, optical efficiency and optical tolerance (acceptance angle) are made in the literature review as well as during theoretical and experimental investigations. The subject of surface structure and its implications on concentrator optics has been discussed in detail while highlighting the need for enhanced considerations towards material and hence the surface quality of optics. All of the findings presented contribute to the development of higher performance CPV technologies. Specifically high and ultrahigh concentrator designs and the accompanied need for high accuracy high quality optics has been supported. A simulation method has been presented which gives attention to surface scattering which can decrease the optical efficiency by 10-40% (absolute value) depending on the material and manufacturing method. New plastic optics and support structures have been proposed and experimentally tested including the use of a conjugate refractive-reflective homogeniser (CRRH). The CRRH uses a reflective outer casing to capture any light rays which have failed total internal reflection (TIR) due to non-ideal surface topography. The CRRH was theoretically simulated and found to improve the optical efficiency of a cassegrain concentrator by a maximum of 7.75%. A prototype was built and tested where the power output increase when utilising the CRRH was a promising 4.5%. The 3D printed support structure incorporated for the CRRH however melted under focused light, which reached temperatures of 226.3°C, when tested at the Indian Institute of Technology Madras in Chennai India. The need for further research into prototyping methods and materials for novel optics was also demonstrated as well as the advantages of broadening CPV technology into the fields of biomimicry. The cabbage white butterfly was proven to concentrate light onto its thorax using its highly reflective and lightweight wings in a basking V-shape not unlike V-trough concentrators. These wings were measured to have a unique structure consisting of ellipsoidal pterin beads aligned in ladder like structures on each wing scale which itself is then tiled in a roof like pattern on the wing. Such structures of a reflective material may be the answer to lightweight materials capable of increasing the power to weight ratio of CPV technology greatly. Experimental testing of the large cabbage white wings with a silicon solar cell confirmed a 17x greater power to weight ratio in comparison to the same set up with reflective film instead of the wings. An ultrahigh design was proposed taking into account manufacturing considerations and material options. The geometrical design was of 5800x of which an optical efficiency of either ~75% with state of the art optics should produce and effective concentration of ~4300x. Relatively standard quality optics on the other hand should give an optical efficiency of ~55% and concentration ratio ~3000x. A prototype of the system is hypothesised to fall between these two predictions. Ultrahigh designs can be realised if the design process is as comprehensive as possible, considering materials, surface structure, component combinations, anti-reflective coatings, manufacturing processes and alignment methods. Most of which have been addressed in this work and the accompanied articles. Higher concentration designs have been shown to have greater advantages in terms of the environmental impact, efficiency and cost effectiveness. But these benefits can only be realised if designs take into account the aforementioned factors. Most importantly surface structure plays a big role in the performance of ultrahigh concentrator photovoltaics. One of the breakthroughs for solar concentrator technology was the discovery of PMMA and its application for Fresnel lenses. It is hence not an unusual notion that further breakthroughs in the optics for concentrator photovoltaic applications will be largely due to the development of new materials for its purpose. In order to make the necessary leaps in solar concentrator optics to efficient cost effective PV technologies, future novel designs should consider not only novel geometries but also the effect of different materials and surface structures. There is still a vast potential for what materials and hence surface structures could be utilised for solar concentrator designs especially if inspiration is taken from biological structures already proven to manipulate light

    11th Annual Undergraduate Research Symposium

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    PROGRAM and PROCEEDINGS THE NEBRASKA ACADEMY OF SCIENCES -- April 22, 2022

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    Aeronautics & Space Science -- Chairperson(s): Dr. Scott Tarry & Michaela Lucas ANTHROPOLOGY SECTION Chairperson: Dr. Taylor Livingston APPLIED SCIENCE & TECHNOLOGY SECTION Chairperson: Mary Ettel BIOLOGICAL SCIENCES SECTION Chairperson: Therese McGinn BIOMEDICAL SCIENCES SECTION Chairperson: Annemarie Shibata CHEMISTRY SECTION Chairperson: Nathanael Fackler EARTH SCIENCES SECTION Chairperson: Irina Filina ENVIRONMENTAL SCIENCES SECTION Chairperson: Mark Hammer PHYSICS SECTION Chairperson: Adam Davis FRIENDS OF THE ACADEMY 2022 Maiben Lecturer: Dan Sitzman 2022 FRIEND OF SCIENCE AWARD TO: Julie Sigmon and Chris Schabe

    2017 Abstracts Student Research Conference

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    Technology 2001: The Second National Technology Transfer Conference and Exposition, volume 1

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    Papers from the technical sessions of the Technology 2001 Conference and Exposition are presented. The technical sessions featured discussions of advanced manufacturing, artificial intelligence, biotechnology, computer graphics and simulation, communications, data and information management, electronics, electro-optics, environmental technology, life sciences, materials science, medical advances, robotics, software engineering, and test and measurement

    Machine Vision: How Algorithms are Changing the Way We See the World

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    Humans have used technology to expand our limited vision for millennia, from the invention of the stone mirror 8,000 years ago to the latest developments in facial recognition and augmented reality. We imagine that technologies will allow us to see more, to see differently and even to see everything. But each of these new ways of seeing carries its own blind spots. In this illuminating book, Jill Walker Rettberg examines the long history of machine vision. Providing an overview of the historical and contemporary uses of machine vision, she unpacks how technologies such as smart surveillance cameras and TikTok filters are changing the way we see the world and one another. By analysing fictional and real-world examples, including art, video games and science fiction, the book shows how machine vision can have very different cultural impacts, fostering both sympathy and community as well as anxiety and fear. Combining ethnographic and critical media studies approaches alongside personal reflections, Machine Vision is an engaging and eye-opening read. It is suitable for students and scholars of digital media studies, science and technology studies, visual studies, digital art and science fiction, as well as for general readers interested in the impact of new technologies on society.publishedVersio

    Chapter 34 - Biocompatibility of nanocellulose: Emerging biomedical applications

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    Nanocellulose already proved to be a highly relevant material for biomedical applications, ensued by its outstanding mechanical properties and, more importantly, its biocompatibility. Nevertheless, despite their previous intensive research, a notable number of emerging applications are still being developed. Interestingly, this drive is not solely based on the nanocellulose features, but also heavily dependent on sustainability. The three core nanocelluloses encompass cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and bacterial nanocellulose (BNC). All these different types of nanocellulose display highly interesting biomedical properties per se, after modification and when used in composite formulations. Novel applications that use nanocellulose includewell-known areas, namely, wound dressings, implants, indwelling medical devices, scaffolds, and novel printed scaffolds. Their cytotoxicity and biocompatibility using recent methodologies are thoroughly analyzed to reinforce their near future applicability. By analyzing the pristine core nanocellulose, none display cytotoxicity. However, CNF has the highest potential to fail long-term biocompatibility since it tends to trigger inflammation. On the other hand, neverdried BNC displays a remarkable biocompatibility. Despite this, all nanocelluloses clearly represent a flag bearer of future superior biomaterials, being elite materials in the urgent replacement of our petrochemical dependence

    KINE[SIS]TEM'17 From Nature to Architectural Matter

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    Kine[SiS]tem – From Kinesis + System. Kinesis is a non-linear movement or activity of an organism in response to a stimulus. A system is a set of interacting and interdependent agents forming a complex whole, delineated by its spatial and temporal boundaries, influenced by its environment. How can architectural systems moderate the external environment to enhance comfort conditions in a simple, sustainable and smart way? This is the starting question for the Kine[SiS]tem’17 – From Nature to Architectural Matter International Conference. For decades, architectural design was developed despite (and not with) the climate, based on mechanical heating and cooling. Today, the argument for net zero energy buildings needs very effective strategies to reduce energy requirements. The challenge ahead requires design processes that are built upon consolidated knowledge, make use of advanced technologies and are inspired by nature. These design processes should lead to responsive smart systems that deliver the best performance in each specific design scenario. To control solar radiation is one key factor in low-energy thermal comfort. Computational-controlled sensor-based kinetic surfaces are one of the possible answers to control solar energy in an effective way, within the scope of contradictory objectives throughout the year.FC

    PROGRAM, THE NEBRASKA ACADEMY OF SCIENCES: One Hundred-Thirty-First Annual Meeting, APRIL 23-24, 2021. ONLINE

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    AFFILIATED SOCIETIES OF THE NEBRASKA ACADEMY OF SCIENCES, INC. 1.American Association of Physics Teachers, Nebraska Section: Web site: http://www.aapt.org/sections/officers.cfm?section=Nebraska 2.Friends of Loren Eiseley: Web site: http://www.eiseley.org/ 3.Lincoln Gem & Mineral Club: Web site: http://www.lincolngemmineralclub.org/ 4.Nebraska Chapter, National Council for Geographic Education 5.Nebraska Geological Society: Web site: http://www.nebraskageologicalsociety.org Sponsors of a $50 award to the outstanding student paper presented at the Nebraska Academy of SciencesAnnual Meeting, Earth Science /Nebraska Chapter, National Council Sections 6.Nebraska Graduate Women in Science 7.Nebraska Junior Academy of Sciences: Web site: http://www.nebraskajunioracademyofsciences.org/ 8.Nebraska Ornithologists’ Union: Web site: http://www.noubirds.org/ 9.Nebraska Psychological Association: http://www.nebpsych.org/ 10.Nebraska-Southeast South Dakota Section Mathematical Association of America: Web site: http://sections.maa.org/nesesd/ 11.Nebraska Space Grant Consortium: Web site: http://www.ne.spacegrant.org/ CONTENTS AERONAUTICS & SPACE SCIENCE ANTHROPOLOGY APPLIED SCIENCE & TECHNOLOGY BIOLOGICAL & MEDICAL SCIENCES COLLEGIATE ACADEMY: BIOLOGY COLLEGIATE ACADEMY: CHEMISTRY & PHYSICS EARTH SCIENCES ENVIRONMENTAL SCIENCES GENERAL CHEMISTRY GENERAL PHYSICS TEACHING OF SCIENCE & MATHEMATICS 2020-2021 PROGRAM COMMITTEE 2020-2021 EXECUTIVE COMMITTEE FRIENDS OF THE ACADEMY NEBRASKA ACADEMY OF SCIENCS FRIEND OF SCIENCE AWARD WINNERS FRIEND OF SCIENCE AWARD TO DR PAUL KAR
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