571 research outputs found
Josephus : noble sicarii suicide or mass-slaughter at Mount Masada? / Nicholas Peter Legh Allen
Full text linkAn attempt is made to ratiocinate historical events at Mount Masada in c. 74 C.E. as related by Josephus Flavius. Cohen (1982:393) clearly sees Josephus as a mostly dishonest historian, one who happily exaggerates and embellishes his accounts. As a consequence of this rhetorical straight-jacket that he places Josephus within, Cohen (for one) cannot accept Josephus’ Masada account as being an “unalloyed version of the truth”. The author analyses Josephus’ track record apropos his recording of other historical events and submits that, rhetorical strategies aside, the historian can largely trust Josephus’ accounts
Considerations for material properties and processes in space and their impact
Full text linkGravity dominates everything on Earth, from the way life has developed to the way many types of materials are formed. Onboard spacecrafts orbiting the Earth or other vehicles in free-fall conditions; however, the influence gravity is barely felt. In this “microgravity environment”, scientists can investigate phenomena, which are impossible on Earth or are masked by the presence of gravity. In this condition various effects are significantly altered, in particular convection, buoyancy, hydrostatic pressure and sedimentation.26 27 In this virtual absence of gravity as we know it, therefore, space flight gives scientists a unique opportunity to study various states of matter (solids, liquids and gases), and discern forces and processes that are interwoven or overshadowed in normal gravity. Accordingly, microgravity can be regarded as an important tool for improving our fundamental understanding of several complex phenomena, which are of great interest in several technological fields
Magnetic fluids in microgravity environments
Full text linkMagnetic fluids such as magneto-rheological fluids and ferrofluids are a class of smart materials composed of magnetic particles dispersed in a conventional carrier liquid which find widespread use in many scientific and engineering problems. Recently, a range of new technological applications based of magnetic-amagnetic fluid pair systems exploiting the ability of the magnetic phase to target desired locations using magnetism for manipulation, transport and actuation guided by magnetic fields have appeared. While in the presence of micro-sized drops buoyancy is often negligible, at larger scales gravity becomes relevant and affects the dynamics of the system. Hence, a need has emerged to investigate the magnetic field-induced motion of large particles of magnetic fluids filtering out the effect of buoyancy through dedicated experiments in microgravity conditions
New methods for the transport and management of lunar regolith
Full text linkIn the field of space exploration, it is essential to assemble and transport particles for various applications, for example transporting lunar and Martian soil (typically regolith), for mining, to study geological aspects and establish habitats on the Moon or Mars. The ability to synthesize complex materials directly in space or build specific structures on the surface of other planets is one the main challenges to be addressed in such a context. In this regard, the utilization of lunar regolith is being explored with regard to several potential applications, e.g., as feedstock for 3D printing and even as a solidsupport substrate for plant growth, a source for extraction of essential plant-growth nutrients, a substrate for microbial populations in the degradation of wastes, a source of O2 and H2, which may be used to manufacture water [1-3]. However, the lunar and Martian soils are difficult to handle, because they are made of abrasive and reactive materials. Regardless of its intended use, the use of lunar regolith is hindered by its intrinsic nature, which makes its management (transfer from the surface of the Moon inside ‘containers’ or transport inside ‘pipes’) relatively difficult. Lunar regolith is characterized by very strong electrostatic effects and internal friction, which strongly limit its ‘flowability’
Why Space? : The Opportunity for Materials Science and Innovation
Full text linkAdvanced materials (and their manufacturing) are one of the 7 transformational ‘technology families’ identified by UK Government, where there is both a key opportunity for growth and existing globally competitive research and development (R&D) expertise tied with industrial strength. Similarly, at both a local and global scale, the space sector continues to grow in both size and ambition. With the development of a robust, space launch and provider ecosystem, the ability to access space is accelerating, bringing with it the key opportunity to harness the space environment to augment this technology family’s development heralding solutions to terrestrial challenges. Coupled with this sizable opportunity, are the significant plans for space infrastructure and exploration, that require novel material and manufacturing processes, enhanced properties, and solutions to achieve these. Therefore, there exists a strong foundation for a cohesive case that could bring these communities together and demonstrate the case to key actors (from funders and policy makers to scientists and entrepreneurs) on the opportunity for materials with space. From fundamental research to applied industry solutions, this paper harnesses perspectives from across these communities to better understand the possibilities for research, innovation, and growth. To build this foundation, it is important to contextualise that materials science is an extremely broad field where scientists seek to understand the formation, structure, and properties of materials on various scales, ranging from the atomic to the microscopic and to the macroscopic (large enough to be visible). The properties a material has (such as strength or electrical conductivity) are determined by its structure. Hence, establishing quantitative and predictive relationships between the way a material is processed, its structure (how atoms or larger inclusions are arranged), and its properties is of paramount importance. Gravity is a major contributing factor to this understanding. Materials processing in general, and metals in particular, are often influenced by gravity-driven mechanisms such as solidification. In this case, the liquid-to-solid transition of pure metals is affected by both convection and sedimentation which will ultimately determine the structure of the material. To better understand the complex relationship of processing to a material’s structure, scientists are exploring the use of microgravity facilities to conduct materials-science experiments, where the aforementioned undesired effects are reduced. This includes the use of both in-orbit based facilities (such as the international space station) as well ground- based facilities (such as drop towers). Studying the effects of the space environment on the properties and behaviour of many fluid and solid “terrestrial systems”, could lead to the development of novel manipulation strategies and materials in space, with properties or functionalities that cannot be obtained in normal gravity conditions. For example, this can inform the development of the next generation of advanced materials with superior physicochemical properties to support human space exploration as well as revolutionising established processes on Earth, including design and manufacturing. R&D in this area, could also help address key roadmap points for space exploration (such as in-situ resource utilisation), as well as those cited in terrestrial R&D roadmaps (such as increasing the efficiency and capacity for novel semi-conductor manufacturing). This in turn can drive global leadership, foster international collaboration and development of novel solutions to terrestrial challenges. Fundamental to enabling this is recognising, championing, and stimulating this opportunity. This paper, its authored contributions, and the derived recommendations within, aim to provide a ‘small step’ on the journey
Access to the space environment and low earth orbit : what are the opportunities
Full text linkFor many years, scientists have been utilising platforms both in orbit and on Earth to conduct fundamental research. The ESA Erasmus archives16, contain a database of more than 4100 funded and/or co-founded R&D experiments related to the space sector, from advanced metallurgical processes in microgravity to how biofilms form. As of September 2023, there are already a number of existing incumbents involved in active flight operations, including Arianne Space, Blue Origin, Boeing, Northrop Grumman, Rocket Lab, SpaceX and Virgin (Galactic) to name a few. There are also a number of active access providers supporting customers to fly R&D payloads in space including organisations like Airbus (Bartolomeo), Axiom Space, Ice Cubes, Space Forge (Forge Star), Kayser Space, Open Cosmos and Sierra Space, again to name a few. These capabilities are augmented through access to analogue platforms on Earth, including Drop Towers (e.g. Zarm Drop Tower), Parabolic flights (e.g. Novespace), Sounding rockets (e.g. Swedish Space Consortium) and centrifuges (e.g. ESA ESTEX Long Arm Centrifuge) allowing researchers to understand the effects of variable gravity on material processes on Earth (examples of research on these platforms is discussed later in this section)
New in-orbit self-assembly principles and manufacturing techniques
Full text linkMany materials (e.g. different types of inorganic and organic alloys) in the liquid state consist of fine particles or droplets dispersed in an external (fluid) matrix. Once the effects of gravity are no longer felt, the different densities of the involved phases no longer represent a constraint forcing the dispersed particles or droplets to separate from the fluid through sedimentation or flotation; exploring self-assembly principles becomes therefore possible. Self-induced particle ordering is indeed emerging as one of the most relevant or promising approaches to develop in-space heterogeneous systems or materials consisting of parts that can recognize and bind to each other or form specific templates or patterns
The Northern Engineer, Vol. 02, No. 1 (Spring 1970)
No full textArctic Coastal and Ocean Engineering / W.F. Weeks -- Icebreaker Gap? / J.E. James Jr. -- Ice Seasons In and Around Alaska / Philip R. Johnson -- Kinetics of Dissipation and Biodegradation Of Crude Oil in Alaska's Cook Inlet / P.J. Kinney ; D.K. Button ; D.M. Schell -- Where Oh Where Has the Lenin Gone? / William R. Hunt -- Port Clarence Sea Ice Testing / Michael J. Tauriainen -- Basic considerations of icebreaker mechanics / E. Staples Brown -- The Underwater Shape of a Grounded Ice Island Off Prudhoe Bay, Alaska / L.R. Breslau ; J.E. James Jr. ; M.D. Trammel ; C.E. Behlke -- Cold Regions Research In Progress: U.S. Army Cold Regions Research and Engineering Laboratory -- Sea Ice Reconnaissance by Satellite Imagery / T.D. Roberts ; H. Nelson -- Planning Marine Structures For Alaska's Arctic Regions / Mark W. Fryer -- Winter Studies Of the Bering Sea / C. Peter McRoy -- Meetings -- Letters To The Editor / Robert B. Weeden -- Reviews -- Current Publications -- International Journal of Heat and Mass Transfer -- U.S. Army Cold Regions Research and Engineering Laboratory -- National Research Council (NRC), Division of Building Researc
A fiscal needs approach to equalization transfers in a decentralized federation
Full text linkThe author reviews the conceptual basis for fiscal equalization transfers, analyzes the theoretical implications for optimal design of equalization transfers, and suggests quantitative approaches for assessing the fiscal needs of subnational governments and determining their entitlement to transfers. The author illustrates proposed methods using data for local and provincial Canadian governments. The proposed methods could be useful tools, he says, for undertaking systematic objective reviews of aggregate and sectoral public spending in developing countries. The author argues that in a decentralized federation, fiscal inefficiencies and inequities arise because of subnational governments'differing levels of ability to provide comparable public services at comparable tax rates. Fiscal equalization transfers that reduce or eliminate differentials in net fiscal benefits create a rare instance in economics when considerations of equity and efficiency coincide. These transfers must allow for differences in the spending needs and revenues-raising abilities of the various subnational governments. The author argues for a two-tiered approach to equalization. The first tier would be a federal responsibility to equalize the burden of federal taxes. The second tier would be an interprovincial equalization fund to be administered by the Council of Provincial Finance Ministers. It would entail a comprehensive equalization system that takes into account provincial spending needs. The standard of equalization would be negotiated.Public Sector Economics&Finance,Banks&Banking Reform,Municipal Financial Management,National Governance,Environmental Economics&Policies
The Empire, the Land, and the Exodus: A Study of How the Roman Empire Literally Shaped Christianity: 1 C.E. - 280 C.E.
Full text linkThis paper explores the factors and trends involved in the movement of Christian communities from Palestine into Asia Minor and regions west of the Aegean Sea. Because the first generation of Christians generally continued to identify themselves as Jewish, this paper looks into the factors that affected the Jewish community with the perspective that a large portion of the early Christians were still members of the Jewish community. Roman land control policies, taxation, and continuous loss and division of land all but pushed many Jews out of the region while the peace of Augustus led many more to depart more voluntarily. It was the culmination of all these factors that led to Jewish emigration from the Palestinian region. The paper will begin with a brief history of the birth of Christianity and the Jewish-Roman relationship in Palestine, followed by a discussion of factors that led to emigration from Palestine, and then end with an analysis of the locations of the Christian communities
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