Design of Meta-material Tank Track System with Experimental Testing and Sensitivity Analysis of Additively Manufactured Meta-material Backer Pads

Operational wear and hysteretic heat loss frequently affect the rubber components of the M1 Abrams main battle tank, leading to deterioration of the material and laborious replace and repair efforts in tactical situations. In previous work at Clemson University, meta-material backer pads had been designed and optimized using the Unit Cell Synthesis method and the Modified Unit Cell Synthesis method to match the characteristic deformation behavior of current elastomer backer pads on the M1 Abrams battle tank. In this case, a meta-material is a periodic, unit cell based, material that exhibits global mechanical properties that differ from the mechanical properties of the constitutive material. After successful optimization results were obtained, physical parts were manufactured using an Electron Beam Melting additive manufacturing process and a Ti-6Al-4V powder, however the behavior of the physical pads was never tested. The work in this research begins here, with the experimental testing and performance comparison of the titanium backer pads against the respective finite element model. Using compressive and high cycle fatigue testing, the behavior of one backer pad was observed, showing a desired nonlinear behavior but larger than expected strain values. Fatigue testing, in turn, resulted in a critical failure prior to meeting the desired and expected number of cycles. To search for causation for these discrepancies, three potential sources for performance deviation were identified through literature and FE model review. A sensitivity analysis was employed to analyze the influence of manufacturing tolerances and material property variation on final performance, which showed significant performance error could be feasibly expected. In tandem with testing, expressed interest in replacing additional rubber track system components led to the design and optimization of a meta-material system. Using MUCS methodology, a circular meta-material for use on the road wheel was designed and optimized. Inadequate results encouraged the introduction of layer multipliers. The multipliers altered the design space and provided several significantly improved design options to choose from. The system design was then carried out, utilizing both a single level and multi-level optimization approach to compare against one another, based on several criteria. Finally, research questions are answered, conclusions are discussed, and the path to future work is provided

The Effect of Signing Ballot Petitions on Turnout

In the Progressive Era, almost half of the U.S. states adopted the ballot initiative, the process by which citizens can petition to change their state’s laws or constitution independent of their state’s legislature. Many Progressives believed the initiative would have positive “educative effects” on voters, such as increasing voter turnout. Most studies show the Progressives’ hypothesis that the initiative would increase turnout was correct, but how and for whom the initiative increases turnout remains disputed. Using two Arkansas initiative petitions and the Arkansas voter registration file, I find that the act of signing a ballot initiative petition significantly increases the likelihood that a citizen will turn out to vote in the subsequent election. However, I find that voters with some, but not consistent, prior voting experience were most spurred to turn out by the 2014 minimum-wage increase petition, while voters with no recent voting experience were most affected by the 2016 medical marijuana legalization petition

Characterising fracture systems within upfaulted basement highs in the Hebridean Islands: an onshore analogue for the Clair Field

The Outer Hebrides are a structurally complex area, comprised predominantly of crystalline basement rocks of the Lewisian Gneiss Complex with the multiply reactivated Outer Hebrides Fault Zone following eastern portions of the islands for over 200 km along strike. In Eastern Lewis, the Permo-Triassic Stornoway Formation unconformably overlies Lewisian basement rocks of the OHFZ in a half-graben. This structural setting is analogous to the major offshore Clair oil field, where oil is found within Devonian-Carboniferous red beds of the Clair Group directly overlying Lewisian Gneiss Complex rocks of the Rona Ridge, which was upfaulted in the Mesozoic. Oil connection and flow has been proven in the basement rocks at Clair, however, little is known about the nature of fracturing and faulting within the basement and how these faults link to the cover sequence. Here, the cover and basement rocks of the Outer Hebridean Islands of Lewis and Harris are studied as an analogue. Faults, fault rocks and deformation are characterised within the Stornoway Formation, and at the basement-cover interface, allowing recognition of Mesozoic and younger faults within the Lewisian and their separation from older structures. Three fault sets are distinguished within the Stornoway Formation: a NNW-SSE striking normal fault set (Set 1); a N-S and E-W quadrimodal normal fault set (Set 2); and a less numerous late E-W strike-slip set (Set 3). Tertiary dolerite dyke intrusion occurred along Set 1 and Set 2 faults prior to the formation of Set 3. Palaeostress analyses reveal that Set 1 and 2 result from E-W and ENE-WSW directed extension vectors, followed by E-W directed contraction associated with Set 3. These orientations are interpreted to be representative of Mesozoic extension related to the opening of the Atlantic, followed by Cenozoic contraction. Faults in the Stornoway Formation are accompanied by development of authigenic clay-bearing gouges and cataclasites, ± calcite cement and late zeolite. Zeolite is often associated with secondary porosity, produced through dissolution of calcite. Mesozoic and younger faults are readily identified in Lewisian Gneiss rocks of the Stornoway region based on fault rock characterisation, and these faults also display an ENE-WSW directed extension vector. The major bounding faults of the Stornoway Formation are sub-parallel with the local foliation and the reactivation of the basement foliation by Mesozoic faults is proven. Fault trends identified within the Stornoway Formation are also sub-parallel with the local foliation. Conjugate faulting apparent in the Stornoway Formation is not present within the Lewisian, possibly indicating a degree of structural detachment between faulting in the basement and faulting in the cover, probably linked to the development of low-angle faults within the Stornoway Formation within metres of and parallel with the basement-cover unconformity. The basement-cover interface displays abundant evidence of fluid overpressure, potentially linked with dewatering during lithification and local fault movements. Mesozoic and younger-age brittle fault rocks post-date pre-existing extensive ductile and brittle deformation that are most intense within the OHFZ. Brittle fault rocks of pre-Mesozoic age are associated with pseudotachylites, fine grained cataclasites, epidote-bearing cataclasites and pumpellyite-bearing cataclasites. Mesozoic fault rocks contain authigenic clay-bearing gouges and cataclasites often associated with zeolite and adularia mineralisation that often accompanies the development of secondary porosity within the fault rocks. This chronological fault rock assemblage represents the continued exhumation of the islands after the successively lower temperature and pressures conditions experienced since the initial development of the basement gneiss complex. Across Lewis, fault rock characterisation allows identification of major Mesozoic and younger structures that cross the islands, with a km-scale offset postulated across the major Seaforth Fault that may link the major NE-SW striking Minch Fault to a NE-SW striking fault lying offshore western Lewis/Harris. On Lewis, the predominant orientation of Mesozoic structures is NNW-SSE, becoming NW-SE on Harris, south of the Seaforth Fault and where foliation becomes pervasively NW-SE. It seems highly likely that, as identified in the Stornoway Region, the foliation orientation plays a significant role in the development of later structures. At Clair, fault rock development within the Devonian-Carboniferous Clair Group is dependent on the host lithology, with gouges formed in mudstones, and granulation seams found in porous, oil-bearing sandstones. Calcite-cemented breccias are present in zones of calcite cemented host rock. Pyrite and calcite vein mineralisation are associated with oil influx, and a late phase of dissolution was accompanied by faulting that produced uncemented brittle fault rocks (gouge). In the basement, oil is seen along open fractures and in vug-like secondary porosity associated with adularia mineralisation, of which two forms are present. Euhedral adularia is often altered to green clay and partially to wholly infills tensile fractures that may predate the emplacement of the Clair Group. Later adularia occurs as ‘speckled’ veins, with haematite, clay, calcite, pyrite, minor zeolite and oil, and appears to be contemporaneous with calcite-pyrite veining (i.e. Mesozoic in age). Porosity in both adularia-bearing fractures is associated with oil staining. The basement displays little evidence of extensive mylonites or phyllonites that are obvious in the OHFZ of the Outer Hebrides. Scalability studies show that it is difficult to assign power-law spacing distributions to fractures within the basement rocks of the Hebrides. Fractures parallel with Mesozoic structures do however tend to display a greater degree of organisation with more clustering of fractures as the faults are approached. Mesozoic fault-perpendicular fracture sets display more strongly random fracture spacing distributions consistent with a jointing origin. At Clair, fracture spacing studies in the cover show a low fracture density compared to basement, with fracture spacing that is clustered and may be well represented by power-laws. Dissolution has locally produced a randomly spaced fracture network. Although fracture spacings in the Hebridean Lewisian are generally random, fracture apertures define a clear power law relationship over ~5 orders of magnitude. Similarly, results from the Clair group also display equivalent power law relationships

A 0-1 integer programming model for the simultaneous allocation of operations of part types and grouping of machine-tool combinations.

In today\u27s competitive world, for manufacturers to survive in the market and to compete on a global level, several innovative strategies are being developed and practised. In industries which manufacture a variety of products in lots, one of the well known manufacturing strategies or systems is cellular manufacturing systems (CMS). CMS has several advantages especially for manufacturers who produce a medium variety of products in medium volumes. The tangible benefits are reduction in cycle time of the product, reduced inventory, improved quality, possibility to meet customer demands on time etc.; the intangible benefits are flexibility in the system, increased control of the process, improvement in employee morale etc. This proposed research is an attempt to group machines into cells, assign tools to the machines, and then to allocate operations of parts to the machine-tool combinations, simultaneously. In this research a 0-1 integer programming model is developed for the purpose mentioned above. The objective of the model is to reduce operation costs, material handling costs and refixturing costs, taking into consideration tooling, machine capacity and tool life.Dept. of Industrial and Manufacturing Systems Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1997 .F68. Source: Masters Abstracts International, Volume: 37-01, page: 0335. Adviser: Reza S. Lashkari. Thesis (M.A.Sc.)--University of Windsor (Canada), 1997

Development of biological hip resurfacing in dogs

Title from PDF of title page (University of Missouri--Columbia, viewed on October 26, 2012).The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Dissertation advisor: Dr. James L. CookIncludes bibliographical references.Vita.Ph. D. University of Missouri--Columbia, 2012."July 2012"Total joint replacement remains an excellent treatment for patients with debilitating joint degeneration. However, joint replacement using non-absorbable prostheses can deteriorate and become loose over time. A superior alternative would involve joint replacement with absorbable, biocompatible materials that facilitate re-generation of native cartilage and bone and that improve with time. Our objective with this research was to develop a femoral head replacement prosthesis for application in dogs. Our work was focused in three areas. First, we successfully developed and produced a prosthesis made of an absorbable material, poly-ε-caprolactone (PCL) with mechanical characteristics that are similar to that of cancellous bone. Second, we determined that use of hydrogen peroxide gas plasma sterilization techniques inhibit canine chondrocyte viability while gamma irradiation techniques provide a more compatible sterilization procedure that should facilitate cellular adhesion and proliferation. Third, we determined that the canine femoral anatomy is similar to humans and determined that accurate placement of a stemmed prosthesis is likely optimized by the fluoroscopic surgical techniques described herein. These results all set the stage for continued pursuit of PCL as a joint replacement material in general and for the canine femoral head specifically.Includes bibliographical reference

Agricultural growth and investment options for poverty reduction in Malawi:

"Malawi has experienced modest economic growth over the last decade and a half. However, agricultural growth has been particularly erratic, and while the incidence of poverty has declined, it still remains high. The Malawian government, within the framework of the Agricultural Development Plan (ADP), is in the process of implementing the Comprehensive Africa Agriculture Development Programme (CAADP), which provides an integrated framework of development priorities aimed at restoring agricultural growth, rural development and food security. This paper analyzes agricultural growth and investment options that can support the development of a comprehensive agricultural development strategy consistent with the principles and objectives of the CAADP, which include achieving six percent agricultural growth and allocating at least ten percent of budgetary resources to the sector. Economic modeling results indicate that it is possible for Malawi to reach the CAADP target of six percent agricultural growth. However, achievement of these goals will require additional growth in most crops and agricultural sub-sectors, meaning that Malawi cannot rely solely on growth in maize or tobacco to reach this growth target. Broader-based agricultural growth, including growth in pulses and horticultural crops, will be important if this target is to be achieved. So, too, is meeting the Maputo declaration of spending at least ten percent of the government's total budget on agriculture. In fact, even under a more optimistic and efficient spending scenario, the Government of Malawi must increase its spending on agriculture in real value terms by about 20 percent per year between 2006 and 2015, and account for at least 24 percent of its total expenditure by 2015 if the CAADP goals are to be met. Although agriculture has strong linkages to the rest of the economy, with agricultural growth typically resulting in substantial overall growth in the economy and rising incomes in rural and urban areas, simply achieving the CAADP target of six percent will not be sufficient to halve poverty by 2015, i.e. achieving the first Millennium Development Goal (MDG1). To achieve this more ambitious target, agriculture and non-agriculture would need an average annual growth rate above seven percent. This growth requirement is substantial, as is the associated resource requirements, indicating that the MDG1 target may be beyond reach. However, achieving the CAADP target should remain a priority, as this goal has more reasonable growth and expenditure requirements, and will substantially reduce the number of people living below the poverty line by 2015 and significantly improve the well-being of both rural and urban households." from authors' abstractAgriculture, GDP, Poverty, Public investment, MDGs, Development strategies,

MDCC: Multi-Data Center Consistency

Replicating data across multiple data centers not only allows moving the data closer to the user and, thus, reduces latency for applications, but also increases the availability in the event of a data center failure. Therefore, it is not surprising that companies like Google, Yahoo, and Netflix already replicate user data across geographically different regions. However, replication across data centers is expensive. Inter-data center network delays are in the hundreds of milliseconds and vary significantly. Synchronous wide-area replication is therefore considered to be unfeasible with strong consistency and current solutions either settle for asynchronous replication which implies the risk of losing data in the event of failures, restrict consistency to small partitions, or give up consistency entirely. With MDCC (Multi-Data Center Consistency), we describe the first optimistic commit protocol, that does not require a master or partitioning, and is strongly consistent at a cost similar to eventually consistent protocols. MDCC can commit transactions in a single round-trip across data centers in the normal operational case. We further propose a new programming model which empowers the application developer to handle longer and unpredictable latencies caused by inter-data center communication. Our evaluation using the TPC-W benchmark with MDCC deployed across 5 geographically diverse data centers shows that MDCC is able to achieve throughput and latency similar to eventually consistent quorum protocols and that MDCC is able to sustain a data center outage without a significant impact on response times while guaranteeing strong consistency

A Study on Quality of Life and Problems of Elderly People

Today India is home to one out of every ten senior citizens of the world. Both the absolute and relative size of the population of the elderly in India will gain in strength in future. Among the total elderly population, those who live in rural areas constitute 78 percent.Given the trend of population ageing in the country, the older population faces a number of problems and adjusts to them in varying degrees. These problems range from absence of ensured and sufficient income to support themselves and their dependents during ill health, absence of social security, loss of social role and recognition, to the non-availability of opportunities for creative use of free time. This research study on the quality of life and problems of elderly person at St. Antony’s oldage home, Kattur, Trichy shows that adapting to old age is dependent on several socio- economic, cultural and psychological facts. The reaserch show that continues research, modification of police and programme are required to make better life  of elderly