Mars was assumed to be very similar to Earth in terms of topography, water, magnetic field, and even the existence of life. However, exploration of the planet in the 1960s by the Mariner missions showed us a very different planet, one very unlike our own. The later discovery by the Mars Global Surveyor (MGS) of the lack of a globally generated magnetic field proved just how different Mars is from Earth. The discovery of strong magnetic remanence (on the order of 20 – 30 A/m) on Mars implies that at some point in Mars’ history there was a magnetic field, and therefore a dynamo. Since a globally active magnetic field is not present, it can also be assumed that the dynamo ceased generation. Basaltic rocks on Earth typically have magnetic remanences between 1 to 4 A/m and do not usually hold on to those remanences for billions of years. In this study, I utilized the information available on the geochemistry, age, and magnetics of Martian rocks in an attempt to find appropriate terrestrial analogs. Seven Earth locations of basaltic rocks (Mauna Loa, Hawaii; Eldgja and Laki eruptions, Iceland; Springerville volcanic complex, Arizona; Taos Plateau volcanic complex, New Mexico; Lascar Volcano, Chile; Tatara-San Pedro volcanic complex, Chile; Patagonia slab window, Argentina) were selected with different tectonic environments, ages, and geochemistries and their rock magnetic properties including natural remanent magnetization (NRM), susceptibility, and hysteresis properties including coercivity were analyzed. Geochemical values were plotted as averages on a silica vs. alkali graph. There was some variation in NRM and susceptibility values for each of the terrestrial locations (such as Taos Plateau), but overall the averages are a good representation of average NRM and susceptibility. None of the samples studied displayed high remanence, high susceptibility, and high coercivity that would indicate stable single-domain magnetite. Although vastly different basalt origins were studied, an analog to the highly magnetized Martian crust was not found. There are three possibilities for this. 1) A basaltic terrestrial analog does exist, yet it was not included in this study. This is a very viable possibility since there are basalts all over the Earth each with a unique origin. 2) A basaltic terrestrial analog does not exist because although the rocks on Mars are basaltic, the global magnetic field that existed billions of years ago on Mars was unlike that of Earth. Recent work (Stanley et al, 2008) has shown that the Martian magnetic field might be completely different from Earth’s, and therefore a terrestrial analog would be impossible to find. 3) A basaltic terrestrial analog does not exist, but a terrestrial analog of a different rock type does exist. The assumption that the surface rocks on Mars – which are known to be mostly basaltic – are the carrier of the high magnetism. There is the possibility that the surface may be the origin of the magnetism, and in the areas of extremely high magnetism the rocks might locally be different. Also, it may not be the surface rocks that are exhibiting the magnetism. It may be buried highly magnetic rocks under a basalt lava flows. In addition to seeking out other basalts as terrestrial analogs for to the highly magnetized Martian rocks, it would also be worthwhile to investigate the possibility of a different magnetic field for Mars and what other terrestrial rocks could display such high magnetism billions of years after the termination of the Martian magnetic field.

No description available.

Unidirectional basalt fiber rods consolidated with an aramid sleeve were measured for compression strength after impact at various energy levels and compared to undamaged control specimens. These structural elements represent local members of open three-dimensional composite lattice structures (e.g., based on isogrid or IsoTruss® technologies) that are continuously fabricated using advanced three-dimensional braiding techniques. The unidirectional core specimens, nominally 8 mm (5/16") and 11 mm (7/16") in diameter, were manufactured using bi-directional braided sleeves or unidirectional spiral sleeves with full or partial (approximately half) coverage of the core fibers. The 51 mm (2") specimens were shorter than the critical buckling length, ensuring the formation of kink bands, typical of strength-controlled compression failure of unidirectional composites. The test results indicate an approximate decrease in the average undamaged compression strength of approximately 1/3 and 2/3 when impacted with 5 J (3.7 ft-lbs) and 10 J (7.4 ft-lbs) for the 8 mm (5/16") diameter specimens and 10 J (7.4 ft-lbs.) and 20 J (14.8 ft-lbs.) for the 11 mm (7/16") diameter specimens, respectively. The aramid sleeves improved the damage tolerance of the composite members, with the amount of coverage having the greatest effect; full coverage exhibiting up to 45% greater strength than partial coverage. Braided sleeves improved compression strength after impact by up to 23% over spiral sleeves, but generally had little effect on damage tolerance. Larger diameter specimens tend to be more resistant to damage than those specimens of a smaller diameter. The compressive material properties for undamaged basalt composites are also presented with the average compressive strength being 800 MPa (116 ksi).

Mineral chemistry and petrography of basalts from the Kimama drill core recovered by Hotspot: Snake River Scientific Drilling Project, Idaho establish crystallization conditions of these lavas. Twenty-three basalt samples, from 20 individual lava flows were sampled from the upper 1000 m (of the 1912 m drilled) core drilled on the axis of the Snake River Plain, and represent approximately 3 m.y. of volcanism (rocks at the bottom of the hole are ~6 Ma). Rock from the upper 1000 m are typically fresh, while those lower in the core are more altered and are less likely to preserve fresh phenocrysts to analyze. Intratelluric phenocrysts (pre-eruption) are: olivine, plagioclase and Cr-spinel inclusions in olivine and plagioclase; groundmass phases (post-eruption) are: olivine, plagioclase, clinopyroxene, magnetite and ilmenite. Olivine core compositions range from Fo84-68, plagioclase cores range from An80-62, clinopyroxene ranges in composition from Wo47-34, En47-28, Fs30-15, spinel inclusions are Cr (up to 20 wt % Cr2O3) and Al-rich (up to 35 wt % Al2O3) and evolve to lower concentrations of Cr and Al and higher Fe and Ti, chromian titanomagnetite to magnetite, and ilmenite are groundmass oxide phases. Thermobarometry of Kimama core basalts indicates that the phenocryst phases crystallized at temperatures of 1155 to 1255°C at depths of 7 to 17 km, which is within or near the seismically imaged mid-crustal sill. Plagioclase hygrometry suggests that these lavas are relatively anhydrous with less than 0.4 wt % H2O. Groundmass phases crystallized at lower temperatures (<1140°C) after eruption. Oxygen fugacity inferred from Fe-Ti oxide equilibria is at or just below the QFM buffer. The origin of the basaltic rocks of the Snake River Plain has been attributed to a mantle plume or to other, shallow mantle processes. Mineral and whole rock major and trace element geochemistry of the olivine tholeiites from the Kimama core are used to distinguish between these two sources (deep or shallow mantle). Whole rock compositions were corrected for plagioclase and olivine fractionation to calculate primary liquids to estimate mantle potential temperatures. Olivine phenocrysts have the pyroxenite source characteristics of low Mn and Ca, but a peridotite source characteristic of low Ni. Thus, trace element models were used to test whether there is pyroxenite in the source of the Snake River Plain basalts, as hypothesized for Hawaii and other plume-related hotspots (e.g., Sobolev et al., 2005; Herzberg, 2011). Olivine chemistry and trace element models establish that the basalt source is a spinel peridotite, not a pyroxenite. The average mantle potential temperature obtained for these samples is 1577°C, 177°C hotter than ambient mantle, suggesting that the basaltic liquids were derived from a thermal plume. Silica activity barometry shows that melt segregation occurs between 80 and 110 km depth, which is within or very near the spinel stability field, and suggests that the lithosphere has been eroded by the plume to a maximum depth of 80 km, and recent mantle tomography suggests that it may be even thinner.

The need for high performance vehicles in the aerospace industry requires materials which can withstand high loads and high temperatures. New developments in launch pads and infrastructure must also be made to handle this intense environment with lightweight, reusable, structural materials. By using more functional materials, better performance can be seen in the launch environment, and launch vehicle designs which have not been previously used can be considered. The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer matrix composites can be used for temperatures up to 260°C. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in the composites. In this study, continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. The oxyacetylene torch testing and three point bend testing have been performed on test panels and the test results are presented.

Thermal protection systems, which are commonly used to protect spacecraft during atmospheric entry, have traditionally been made of materials which are traditionally high in manufacturing costs for both the materials needed and the manufacturing complexity, such as carbon-carbon composites and aerogels. [1] In addition to their manufacturing costs, these materials are also limited in their strength, such as PICA, in a way that necessitate the use of tiles as opposed to single structures because they are not capable of supporting larger structures. [2] The limitations of polymer reinforced composites have limited their entry into these applications, except for pyrolyzed composite materials, such as carbon-carbon and ceramic composites. These materials have been successfully demonstrated their utility in extreme environments, such as spacecraft heat shields, but their high costs and the difficulty to manufacture them have limited their use to similarly high performance applications where the costs are justifiable. Previous work by others with “fuzzy fiber” composites have shown that aligned carbon nanotubes (CNTs) grown on fibers can improve their thermal conductivity and wettability. To this end vertically aligned CNTs were studied for their potential use, but found to be difficult to process with current conventional techniques. A composite material comprised of basalt, a relatively new reinforcing fiber, and phenolic, which has been used in high-temperature applications with great success was made to attempt to create a new material for these applications. To further improve upon the favorable properties of the resulting composite, the composite was pyrolyzed to produce a basalt-carbon composite with a higher thermal stability than its pristine state. While testing the effects of pyrolysis on the thermal stability, a novel iv technique was also developed to promote in-situ carbon nanotube growth of the resulting basaltcarbon composite without using a monolithic piece of cured phenolic resin in place of the standard aromatic hydrocarbon-catalyst precursor. [3, 4] The in-situ growth of carbon nanotubes (CNTs) was explored as their thermal stability [5] and effectiveness in improving performance has been previously demonstrated when used as a resin additive [6]. The specimens were examined with SEM, EDS, and TGA to determine the effects of both pyrolysis and CNT growth during pyrolysis of the basalt phenolic composites. These tests would confirm the presence of CNTs/CNFs directly grown in the composite by pyrolysis, and confirm their composition by EDS and Raman spectroscopy. EDS would additionally confirm that the surface of the basalt fibers possess a composition suitable for CNT growth, similar to the parameters of CVD processing. Additional testing would also show that the growth behavior of the CNTs/CNFs is dependent on temperature as opposed to composition, indicating that there is a threshold temperature necessary to facilitate the availability of catalysts from within the basalt fibers. The thermal stability shown by TGA indicates that the process of pyrolysis leaves the newly formed composite with a high degree of thermal stability, making the new materials potentially usable in applications such as turbines, in addition to large-scale thermal protection systems.

This paper presents test results and code predictions of four continuously and two simply supported concrete slabs reinforced with basalt fibre reinforced polymer (BFRP) bars. One continuously supported steel reinforced concrete slab was also tested for comparison purposes. All slabs tested were 500 mm in width and 150 mm in depth. The simply supported slabs had a span of 2000 mm, whereas the continuous slabs had two equal spans, each of 2000 mm. Different combinations of under and over BFRP reinforcement at the top and bottom layers of slabs were investigated. The continuously supported BFRP reinforced concrete slabs exhibited larger deflections and wider cracks than the counterpart reinforced with steel. Furthermore, the over reinforced BFRP reinforced concrete slab at the top and bottom layers showed the highest load capacity and the least deflection of all BFRP slabs tested. All continuous BFRP reinforced concrete slabs failed owing to combined shear and flexure at the middle support region. ISIS-M03-07 and CSA S806-06 design guidelines reasonably predicted the deflection of the BFRP slabs tested. However, ACI 440-1R-06 underestimated the BFRP slab deflections and overestimated the moment capacities at mid-span and over support sections.

yes / This paper presents experimental results of three continuously supported concrete slabs reinforced with basalt-fibre-reinforced polymer (BFRP) bars. Three different BFRP reinforcement combinations of over and under reinforcement ratios were applied at the top and bottom layers of continuous concrete slabs tested. One additional concrete continuous slab reinforced with steel bars and two simply supported slabs reinforced with under and over BFRP reinforcements were also tested for comparison purposes. All slabs sections tested had the same width and depth but different amounts of BFRP reinforcement. The experimental results were used to validate the existing design guidance for the predictions of moment and shear capacities, and deflections of continuous concrete elements reinforced with BFRP bars. The continuously supported BFRP reinforced concrete slabs illustrated wider cracks and larger deflections than the control steel reinforced concrete slab. All continuous BFRP reinforced concrete slabs exhibited a combined shear–flexure failure mode. ACI 440-1R-15 equations give reasonable predictions for the deflections of continuous slabs (after first cracking) but stiffer behaviour for the simply supported slabs, whereas CNR DT203 reasonably predicted the deflections of all BFRP slabs tested. On the other hand, ISIS-M03-07 provided the most accurate shear capacity prediction for continuously supported BFRP reinforced concrete slabs among the current shear design equations.

No description available.

The Round Lake Batholith is a composite granitic intrusion into the Archean metavolcanics of the Abitibi Greenstone Belt, Superior Province. The mafic metavolcanics are mainly high iron tholeiitic basalts of ocean floor origin. The intrusion of the batholith has metamorphosed the metavolcanics to amphibolite grade. Moving towards the contact there is no change in the metavolcanics grain size, but mineralogy changes quickly from the actinolite zone with relict pumpellyite to the hornblende zone. Field evidence as well as thin section and chemical analyses have shown that the dioritic appearing hybrid rock, near the contact, is a product of the mafic meta volcanics assimilation into the batholith. / Thesis / Bachelor of Science (BSc)