It is possible to create laminae that have spatially varying fiber orientation with a tow placement machine. A laminate which is composed of such plies will have stiffness properties which vary as a function of position. Previous work had modelled such variable-stiffness laminae by taking a reference fiber path and creating subsequent paths by shifting the reference path. This thesis introduces a method where subsequent paths are truly parallel to the reference fiber path. The primary manufacturing constraint considered in the analysis of variable-stiffness laminates was limits on fiber curvature which proved to be more restrictive for parallel fiber laminae than for shifted fiber. The in-plane responses of shifted and parallel fiber variable-stiffness laminates to either an applied uniform end shortening or in-plane shear were determined. Both shifted and parallel fiber variable-stiffness laminates can redistribute the applied load thereby increasing critical buckling loads compared to traditional straight fiber laminates. The primary differences between the two methods is that parallel fiber laminates are not able to redistribute the loading to the degree of the shifted fiber. This significantly reduces the increase in critical buckling load for parallel fiber variable-stiffness laminates over straight fiber laminates. / Master of Science

<p> Tow Hill is a 109m butte located on the north shore of Graham Island, Queen Charlotte Islands. It is composed of a massive, 105m thick layer of olivine tholeiite, underlain by thin sills of tholeiitic basalt and interbedded sediments of the Skonun Formation. The age of this basalt body has been estimated to be less than 5Ma. Three hypotheses have been proposed as to the origin of Tow Hill: 1. a sill intrusion; 2. hydroclastic material; and 3. a lava flow or flows. Macroscopic features observed on Tow Hill do not indicate an origin and each of the three hypotheses can adequately explain the features. Petrographical studies indicate that the basalt is not fragmental and thus, the second hypothesis can be rejected. Neither of the two remaining hypotheses can be strictly accepted or rejected with petrographical examination. Chemical analyses indicate that Tow Hill is made up of "within plate" basalts which are probably related to activity associated with rifting and/or transtension in a continental environment. This constrains the late Tertiary tectonic history of the Queen Charlotte Islands in that any model of the tectonics of this area must involve rifting and/or transtension.</p> / Thesis / Bachelor of Science (BSc)

Föreliggande arbete tar sin utgångspunkt i Försvarsmaktens befintliga förmåga att verka med pansarvärnsrobotar. Med syfte att undersöka om det eventuellt finns ett tomrum att fylla för pansarbrytande robotsystem och att jämföra befintligt system mot föregående och ge förslag på önskvärda förmågor. Ur historik, äldre studier, teknisk data från föregående system och intervjuer dras slutsatser som ligger till grund för värderingar av det existerande behovet. Resultatet visar att pansarvärnsrobot 57 har god möjlighet till att lösa given uppgift om systemet tillförs i större omfattning inom skytteförbanden. Miljön styr taktiken, taktiken styr nyttan vilket i sin tur genererar effekt med systemet. En uppgradering av 57-systemet bedöms värt att beakta för försvarsmakten inom ramen för vilka behov som existerar. / Present work is based on the Armed Forces' existing ability to operate with anti-tank missiles. With the objective to investigate whether there is a void to fill for armor piercing missile systems and to compare the existing system with previous and suggest desirable abilities. From history, older studies and technical data from the previous system and interviews are conclusions drawn and underlying the values of the existing need. The results show that anti-tank missile 57 has good potential to solve the given task if the system is applied on a larger scale within infantry units. The environment decide tactic, the tactic control benefits, which in turn generates effect with the system. An upgrade of the 57-system is deemed worth consideration for the armed forces in the context of the needs that exist.

As a town reliant on the waters of northern Lake Buchanan, Tow, Texas has been devastated by the state's ongoing drought, which began in 2008. For six years the water has been low. For the past two years, the lake has vanished. Tow locals say the problems stem from both poor water management and natural disaster. Water authorities contend the lakes are functioning properly, that the water has dwindled due to the large number of water users and the harsh and unpredictable Texas climate. Regardless of the cause, the lack of water in Tow has ruined a beautiful lake, destroyed individual livelihoods and crippled a small town's economy. This is the story of several Tow locals' struggle to stay afloat through a drought that could soon become the drought of record. / text

Carbon fibre reinforced polymer matrix composites (CF PMCs) are increasingly used in state-of-the-art aerospace applications. Aerospace manufacturers favour components made of CF PMCs over those made of traditional metallic alloys because of their light weight and corrosion resistance, which lead to significant improvements in fuel consump- tion, increased payload capability, and reduced maintenance and inspection costs. How- ever, manufacturing of CF PMC components is performed differently than traditional material in all stages – design, prototyping and production – and therefore, many com- mercial manufacturers have only recently begun producing components with CF PMCs. The first half of this thesis was written as a contribution to the CRIAQ COMP-501 project, which focusses on investigating the cost-effective procurement of airframe com- ponents that are manufactured from final-thickness, net-shaped, and through-thickness reinforced CF preforms. Reinforcement preforms were assembled from commercial 2D woven fabric using stacks of various configurations of structural through-thickness CF stitch. The contribution herein provides the results obtained from investigations into the mechanical behaviour of the relevant reinforcements, when subjected to pre-infusion op- erations typical to RTM VARTM; mechanical behaviour in compaction, shear (draping) and bending (forming). The second half of this thesis presents the major developments which were made to an alternative process for producing thick 3D preforms with great versatility, a process originally proposed as a candidate for supplying preforms to the COMP-501 project. This process interfaces a proprietary kinematic drape optimization (CAD) software with proprietary automated dry fibre placement assembly (CAM) machinery to produce vari- able or final-thickness reinforcements which are highly-drapable and can lay steered tow yarns.

Föreliggande arbete tar sin utgångspunkt i en observation av hur United States Marine Corps (USMC) använde pansarvärnsrobotförband förvånansvärt aggressivt under Gulfkriget 1991. Med syftet att studera denna taktik och att därigenom skapa en ökad förståelse för pansarvärnsrobotförbandens taktiska möjligheter/begränsningar skapas en problemformulering som undersöker vilken relevans USMC:s taktik med pansarvärnsrobotförband i Operation DESERT STORM har för svenska armén idag? För att kunna besvara denna övergripande fråga bryts den ned till tre forskningsfrågor som beskriver vilken taktik som karaktäriserade USMC:s pansarvärnsrobotförband, därefter förklarar motiven för denna taktik och slutligen värderar vilka lärdomar som svenska armén kan dra från detta 2012. Resultatet visar att marinkårens taktik i huvudsak har låg relevans på grund av de unika förutsättningar avseende terräng, siktförhållanden och teknikasymmetri som förelåg i Persiska viken 1991. Terrängen var nästan helt platt vilket gav god effekt för pansarvärnsrobotarnas övertag i skjutavstånd gentemot irakiska stridsvagnar. Oljerök och dimma gjorde att deras termiska sikten kunde verka där inga irakiska motsvarigheter fanns. Konceptet Combined Anti Armor Team bedöms värt att beakta för armén inom ramen för kombinerade vapen och slutförande av Insatsorganisation 2014.

The development of digital technology permits the storage and processing of binary data at high rates, with high precision and density. Therefore, over the past few decades, Moore's law has pushed the development of scaling semiconductor devices for computing hardware. Although the current downward scaling trend has reached its scaling limits, a new "More-than-Moore" (MtM) trend has been emphasized as a diversified function of data collection, storage units, and processing devices. The function diversification defined in MtM can be viewed as an alternative form of "scaling down" for electronic systems, as it incorporates non-computing functions into digital ones, allowing digital devices to interact directly with the environment around them. Two-dimensional (2D) materials display promising potential for combining optical sensing and data storage with broadband photoresponse, outstanding photoresponsivity, rapid switching speed, multi-bit data storage, and high energy efficiency. In this work, in-solution 2D materials flakes (Hafnium Diselenide (HfSe2) and Germanium Selenide (GeSe) have been studied as a charge-trapping layer in non-volatile memory through the seamless fabrication process. Furthermore, the behavior of fabricated non-volatile memories under light illumination has been investigated towards in-memory light sensing. Atomic Force Microscopy, RAMAN spectroscopy, and X-ray Diffraction Spectroscopy characterized the charge-trapping materials. The electrical characterization of Metal Oxide Semiconductor (MOS) Capacitor memory revealed a memory window of 4V for the HfSe2 device under ±10V biasing. Intriguingly, the GeSe device exhibited an extraordinarily wide memory window of 11V under the same electrical biasing. Furthermore, the memory endurance for both materials as charge trapping layer (CTL) exceeds the standard threshold of electrical programming and erasing cycles. The accelerated retention test at different temperatures showed the memory device's stability and reliability for both materials. Under light stimuli with electrical readout voltage, the MOS memory exhibited wavelength and intensity-responsive behavior. The MOS memory of HfSe2 has demonstrated remarkable capabilities in storing the detected light signal, while also exhibiting a noteworthy increase in the memory window of approximately 1.8 V when subjected to a laser wavelength of 405 nm. Meanwhile, the GeSe device's CV measurement revealed a similar trend with the greatest memory window enhancements occurring in relation to 465 nm laser wavelength. Under ±6 V biasing in the absence of light, the memory window was found to be 8.3 V. However, following exposure to a 465 nm laser, this value increased significantly to 9.9 V, representing an increment of 1.6 V. In addition, both devices exhibited distinct sensing of various light intensities and an enhanced memory window as a result of the observable Vt shift caused by altering the levels of illumination. This memory enhancement suggests that photoexcited carriers in the CTL layer were responsible for the optical memory behavior. The 2D materials as CTL pave the way for a reconfigurable optical memory with multilevel optical data storage capacity. This research represents a significant step towards the development of a new generation of memory devices that can store and retrieve data using light signals.

The objective of this research was to explore and demonstrate the production andperformance of fiber-reinforced polymer (FRP) rebar manufactured on a continuous threedimensionalbraiding machine for use as reinforcement in concrete structures. Differentconfigurations of fiberglass/epoxy composite cylindrical rebar rods were manufactured,embedded in concrete, and tested in axial tension to identify the relationships betweenmanufacturing parameters and tensile pull-out strength of the rebar. The strength of the bondbetween concrete and FRP rebar was investigated using the pull-out test detailed by ACI 440.3R-12. The rebar was a No. 4 size and produced by combining multiple tows of fiberglass/epoxyprepreg to form the core of cylindrical rods which were consolidated using spirally-woundaramid consolidation fibers. The manufactured rebar was cured at 121°C (250°F) as specified bythe material manufacturer, TCR Composites. Preliminary research performed on carbon/epoxyrebar guided the process of developing a test matrix based on multiple variables. Primaryvariables investigated included the nature of the consolidation fiber material (dry vs prepreg),and the use of sand coating as a secondary process. The rebar samples were cast in 200 mm x200 mm x 200 mm (8.0 in x 8.0 in x 8.0 in) concrete cubes to investigate bond strength. A testfixture was designed and fabricated for use on a universal tensile testing machine. Standard 12.7mm (0.5 in) diameter steel rebar and a commercially comparable fiberglass rebar were alsotested to provide baseline values. Measurements were collected at both the free and loaded endsof the rebar with free-end results being a more accurate presentation of rebar bond stress.Results showed that the bond strength was 6-13% higher for the free-end for rebarconsolidated with a dry tow compared to prepreg tow consolidated rebar. When sand was added,dry tow consolidated sand-coated samples showed higher bond stress in the range of 15-26% forthe free-end than samples consolidated with a dry tow but excluded sand coating. Samplesconsolidated with prepreg tow and coated with sand showed higher bond stress in the range of43-58% for the free-end compared to prepreg tow no-sand coating samples. Overall, for therebar manufactured on the 3-D braiding machine, the prepreg tow consolidated rebar samplesrecorded the highest bond strength values with a maximum average bond stress value of 15.2MPa (2.26 ksi). The dry tow sand consolidated rebar recorded a maximum average bond stressvalue of 11.4 MPa (1.65 ksi). The rebar purchased from American Fiberglass Rebar recorded amaximum average bond stress of 12.0 MPa (1.74 ksi) while the maximum average bond stress ofsteel rebar was 13.1 MPa (1.90 ksi). Results demonstrated that quality composite rebar can bemanufactured using the 3-D braiding machine and that consolidating the rebar with a prepregtow and coating the surface with sand resulted in a rebar which bonded well with concretecompared to commercialized FRP and steel rebar.

The objective of this research was to explore and demonstrate the production andperformance of fiber-reinforced polymer (FRP) rebar manufactured on a continuous threedimensionalbraiding machine for use as reinforcement in concrete structures. Differentconfigurations of fiberglass/epoxy composite cylindrical rebar rods were manufactured,embedded in concrete, and tested in axial tension to identify the relationships betweenmanufacturing parameters and tensile pull-out strength of the rebar. The strength of the bondbetween concrete and FRP rebar was investigated using the pull-out test detailed by ACI 440.3R-12. The rebar was a No. 4 size and produced by combining multiple tows of fiberglass/epoxyprepreg to form the core of cylindrical rods which were consolidated using spirally-woundaramid consolidation fibers. The manufactured rebar was cured at 121C (250F) as specified bythe material manufacturer, TCR Composites. Preliminary research performed on carbon/epoxyrebar guided the process of developing a test matrix based on multiple variables. Primaryvariables investigated included the nature of the consolidation fiber material (dry vs prepreg),and the use of sand coating as a secondary process. The rebar samples were cast in 200 mm x200 mm x 200 mm (8.0 in x 8.0 in x 8.0 in) concrete cubes to investigate bond strength. A testfixture was designed and fabricated for use on a universal tensile testing machine. Standard 12.7mm (0.5 in) diameter steel rebar and a commercially comparable fiberglass rebar were alsotested to provide baseline values. Measurements were collected at both the free and loaded endsof the rebar with free-end results being a more accurate presentation of rebar bond stress.Results showed that the bond strength was 6-13% higher for the free-end for rebarconsolidated with a dry tow compared to prepreg tow consolidated rebar. When sand was added,dry tow consolidated sand-coated samples showed higher bond stress in the range of 15-26% forthe free-end than samples consolidated with a dry tow but excluded sand coating. Samplesconsolidated with prepreg tow and coated with sand showed higher bond stress in the range of43-58% for the free-end compared to prepreg tow no-sand coating samples. Overall, for therebar manufactured on the 3-D braiding machine, the prepreg tow consolidated rebar samplesrecorded the highest bond strength values with a maximum average bond stress value of 15.2MPa (2.26 ksi). The dry tow sand consolidated rebar recorded a maximum average bond stressvalue of 11.4 MPa (1.65 ksi). The rebar purchased from American Fiberglass Rebar recorded amaximum average bond stress of 12.0 MPa (1.74 ksi) while the maximum average bond stress ofsteel rebar was 13.1 MPa (1.90 ksi). Results demonstrated that quality composite rebar can bemanufactured using the 3-D braiding machine and that consolidating the rebar with a prepregtow and coating the surface with sand resulted in a rebar which bonded well with concretecompared to commercialized FRP and steel rebar.

No description available.