Eating my way through Berrien County

Hydraulic systems are indispensable in many areas of mechanical engineering, where those systems provide the necessary forces and moments. At the same time, hydraulic systems are subject to a trend towards cost reduction and increased efficiency, which means, among other things, that the tanks of the systems are reduced in size or in some cases completely omitted. As a result, the pressure medium in the circuit cannot rest sufficiently and foreign matter, such as particles or foreign liquids, cannot be separated or can only be separated incompletely. The entry of these foreign substances must therefore be effectively prevented in advance in order to guarantee a sufficient service life of the systems. An example of the introduction of such foreign substances is the entrainment of water, which can enter via the dynamic sealing area between the sealing body and the piston rod of a hydraulic cylinder. A distinction can be made between the entry of free water and the entry of water dissolved in the lubricating layer. In the first part of this work, the mechanisms of the entry of dissolved water via rod sealing systems are systematically investigated. Based on the underlying models of the sealing mechanism, the entrainment of water dissolved in the lubricating film is modelled. The basis for the model is the knowledge of the water dissolving capacity of the pressure fluids as well as the properties of the fluids as a function of the dissolved water content. Furthermore, the absorption mechanisms of water into the lubricating film are investigated and the saturation process is modelled, parameterised and validated by experimental tests. In the second part the entrainment of free water is investigated. Based on the sealing mechanism, the entrainment is modelled. The model is validated by means of a test bench and common sealing systems are systematically measured for different operating points. Subsequently, the influence of wipers on the water entrainment is investigated. The results obtained are then transferred to the application case of a mini-excavator, which makes it possible to estimate the amount of water entrained

30 Years at Heshbon

In 1968, Andrews professor of archaeology Siegfried Horn selected the Jordanian village of Hesban as the site of the university’s archaeological attention. Focus visits Jordan for the 30th anniversary celebration and takes you on location

Development of an Inflatable Airlock for a Deep Space Gateway

Inflatable structures technology utilizes high-strength fabric materials and internal pressure to create a stiffened pressure vessel that can replace traditional metallic primary structure in a habitable spacecraft. The flexibility of fabric structures allows them to be compactly stowed for launch and expanded in space, providing significant launch volume savings. The unique construction and design flexibility of these structures can be customized for a variety of uses in space including landing bags, decelerators, long duration in-space and planetary surface habitats, and even airlocks. An airlock is often a required component of a crewed spacecraft to allow for maintenance and human exploration outside of the vehicle. Airlock designs in use today rely on complex hatches and seals connected by metallic walls. Recent developments towards the design of an inflatable airlock structure show feasibility and a significant launch volume savings over a traditional metallic design. This paper will provide a high-level summary of these projects and the current state-of-the-art in inflatable airlock development with additional references and detail about previous and on-going research, providing guidance for the design of a softgoods airlock system. The use of inflatables in space has been in development since the 1960's for both habitats and airlocks. The first ever EVA was conducted by the USSR in 1965 using an inflatable airlock known as the Volga. This airlock was attached to the Voskhod 2 spacecraft and turned the vehicle into a dual chamber airlock. The airlock was successfully deployed, used and jettisoned after Alexey Leonov's historic spacewalk. Additional work on human-rated inflatable structures was not continued until the late 1990's when NASA-JSC led an effort to demonstrate these structures as feasible long-term pressurized elements with the TransHab project. The technology developed and pioneered during this project led to multiple patents and proven feasibility that inflatables could be used for large habitable structures. Following TransHab, Bigelow Aerospace continued the development of inflatable structures with technical support from NASA. This partnership eventually led to the successful flight certification, launch, attachment and deployment of the Bigelow Expandable Activities Module (BEAM) on the ISS in 2016. Inflatable and expandable airlock structures have undergone various detailed feasibility studies and testing for over 15 years, most notably with the Advanced Inflatable Airlock (AIA), Dual-Chamber Hybrid Inflatable Suitlock (DCIS), Minimalistic Advanced Soft Hatch (MASH), and Lightweight External Inflatable Airlock (LEIA). During this time, full-scale articles have been built and pressure-tested, and mock-ups and demonstrators have been constructed and evaluated. During the 2001-2003 timeframe, the AIA concept was matured through requirements development, conceptual design, subscale and full-scale engineering breadboards subjecting various test articles to deployment and pressure testing up to four times operating pressure. These tests proved the feasibility of successful deployment and structural integrity of an inflatable crewlock. Additional testing was performed in the ensuing years, as funding permitted, to further refine additional structural and deployment concepts and to understand the EVA crewmember interfaces, hatches and EVA support equipment interfaces that would be required for a fully functioning airlock. This work resulted in a refinement of the structural requirements and an accounting of the systems needed in an inflatable airlock. In 2014, the MASH project developed an ultra-lightweight airlock concept with a fabric hatch that utilized a unique pressure vessel shape to minimize structural loads around a linear seal. The concept uses an automated zipper-like seal that allows for crew egress/ingress. Most of the development work on the project thus far has focused on the design, analysis and testing of the primary structure and the zipper-like seal system is in the preliminary stages of development with a successful proof-of-concept test. As part of the 2017 LEIA effort, studies were conducted on EVA crewmember interfaces on the inside of an inflatable airlock. These efforts included the design of an internal secondary structure and placement of handholds and foot restraints to enable hatch opening, closing and translation through the airlock. Structural design, analysis and testing was completed on several secondary structure candidates. Crew interface testing was also completed using an inflatable crewlock mockup and the JSC Active Response Gravity Offload System (ARGOS) to simulate the movement of an EVA crewmember through an inflatable crewlock in microgravity. The results of these tests helped demonstrate the feasibility of utilizing an inflatable structure as an airlock and informed the required volume, hatch size, and configuration and location of translation aids for crewmembers in a microgravity crewlock. The ISS Quest airlock uses a dual-chamber design with isolated compartments known as the equipment-lock and the crewlock. The equipment-lock houses the Servicing, Performance and Checkout Equipment (SPCE) items (suit batteries, consumables, etc.) while the crewlock has limited internal hardware and is the nominally depressurized compartment during US EVAs. While inflatable dual chamber airlocks have been studied, the current state of the art emphasizes an inflatable crewlock-type structure attached to a rigid equipment-lock type or habitat structure. Since a large portion of the hardware in the equipment-lock are rigid components and connectors that are installed on the ground - and an inflatable structure does not achieve full structural capabilities until pressurized in space - a depressurized fabric structure cannot provide the capabilities of a full equipment-lock. The use of an inflatable as a crewlock, however, provides all the required capabilities for EVA operations in a small launch package that offers significant volume savings over a metallic crewlock. The functions of a traditional equipment lock, including the SPCE, could be provided by a spacecraft's habitat module or node and not necessarily in a separate equipment lock. An inflatable crewlock would be attached to the vehicle and launched in a packed and compressed state, saving volume under the launch shroud and mass for the overall airlock element compared to a rigid crewlock. Work is currently underway to continue development of an inflatable airlock with a variety of focus areas including the consideration of crew-induced loads and interfaces, the design and development of an internal sub-structure to provide translation aids and restraints, the thermal considerations of a fabric shell depressurized during an EVA, the micrometeorite environment in deep space, and the packaging and deployment of an inflatable airlock

Characterizing the variation of propagation constants in multicore fibre

We demonstrate a numerical technique that can evaluate the core-to-core variations in propagation constant in multicore fibre. Using a Markov Chain Monte Carlo process, we replicate the interference patterns of light that has coupled between the cores during propagation. We describe the algorithm and verify its operation by successfully reconstructing target propagation constants in a fictional fibre. Then we carry out a reconstruction of the propagation constants in a real fibre containing 37 single-mode cores. We find that the range of fractional propagation constant variation across the cores is approximately $\pm2 \times 10^{-5}$.Comment: 17 pages; preprint format; 5 figures. Submitted to Optics Expres

Canada Council's Killam Research Fellowships: Distribution of Awards 1968-84

An analysis of the distribution of Killam Research Fellowships awarded by Canada Council over a seventeen-year period reveals a pattern which is examined in relation to the distribution of applications from universities. The existing situation is discussed with reference to previous studies of peer review systems and to implications for Canadian research. Encouragement of increased participation across Canada is suggested as one possible concern for Canada Council policy.Les résultats d'une analyse de la répartition des bourses de chercheur-boursier de la fondation Killam, allouées par le Conseil des Arts du Canada sur une période de dix-sept années, et la répartition des demandes de bourses provenant de différentes universités ont fait l'objet d'une étude comparative. L'on discute de la situation actuellement par rapport à des études préalables sur les mécanismes d'évaluation par les pairs et leurs répercussions sur la recherche au Canada. On suggère que la politique du Conseil des Arts encourage, entre autres, une participation active et grandissante dans tout le Canada

Cache CountyCommunity Survey of Future Landfill Alternatives

State University in the spring of 2003. The purpose of this survey was to gather scientific information regarding the concerns, perceptions, and preferences of Cache County adults related to various future landfill siting options. The survey was conducted at the request of local officials, the Countywide Service District, and various advisory committees established to make recommendations on a future Cache County landfill site

Using Common Gardens and AFLP Analyses to Identify Metapopulations of Indigenous Plant Materials for Rangeland Revegetation in Western USA

Past mismanagement, overgrazing, invasive weedy species, wildfires, marginal crop production, mineral and energy extraction, recreation and global climate change are challenges currently facing rangelands (Pierson et al. 2011). These disturbances may lead to long-term reductions in biodiversity, altered nutrient and water cycling, diminished forage production for livestock and wildlife, increased wildfire frequency and increased soil erosion and stream sedimentation (Sheley et al. 2008). Rangeland revegetation with desirable plant materials may be required to improve degraded conditions, speed recovery, and prevent further erosion and degradation. There is a critical need for plant materials to restore and revegetate rangeland ecosystems. Legumes indigenous to western North America are of particular interest for revegetation because they provide biologically fixed nitrogen, increase plant production, enhance forage quality and provide food sources for grazing animals and pollinators. Some land managers in the USA are concerned with the genetic identity of populations used for revegetation. To balance concerns of genetic identity, ecological adaptation, and economical seed production, we assessed genetic variation and its phenotypic expression in Astragalus filipes Torr. ex A. Gray (basalt milkvetch), Dalea ornata (Douglas) Eaton & Wright (western prairie clover) and D. searlsiae (A. Gray) Barneby (Searls’ prairie clover) using common-garden and AFLP (amplified fragment length polymorphism) techniques. These data were used to define population structures (genetically differentiated groups) within each species, which served as a basis for commercial release and rangeland revegetation (Johnson et al. 2012)