On the periodicity of irreducible elements in arithmetical congruence monoids

Arithmetical congruence monoids, which arise in non-unique factorization theory, are multiplicative monoids $M_{a,b}$ consisting of all positive integers $n$ satsfying $n \equiv a \bmod b$. In this paper, we examine the asymptotic behavior of the set of irreducible elements of $M_{a,b}$, and characterize in terms of $a$ and $b$ when this set forms an eventually periodic sequence

Gas leakage and distribution characteristics of methyl bromide and sulfuryl fluoride during fumigations in a pilot flour mill

The half-loss time (HLT) is used as an indicator to quantify gas leakage rates during methyl bromide (MB) and sulfuryl fluoride (SF) fumigations. Comparisons of HLTs between three MB and three SF fumigations were quantified in the Hal Ross pilot flour mill, Department of Grain Science and Industry, Kansas State University, USA. The sealing quality or gas tightness of the mill before each fumigation was verified by a pressurization test. Fumigant concentrations during the six fumigations were monitored continuously at 30 locations among the five mill floors during the 24 h fumigation period. A weather station on the mill roof monitored barometric pressure, wind speed and direction, temperature, and relative humidity. A data logger on each mill floor recorded temperature and relative humidity. The pressurization test showed that the relationship between airflow rate and building static pressure varied among the fumigations despite the same areas being sealed by two separate fumigation service providers due to environmental conditions not being identical among the fumigations. Concentrations of both fumigants within the mill ranged from 2 to 7 g/m³ . The observed HLTs for the MB and SF fumigations were in the range of 3.61 to 28.64 h and 9.97 to 31.65 h, respectively, and were inversely related only to wind speeds during fumigation and not any other environmental conditions recorded. In our study, the fumigant leakage rate was found to be predominantly a function of wind speed rather than inherent gas characteristics of MB and SF

Purification and properties of porcine cardiac desmin and vascular smooth muscle vimentin

The purposes of this study were to purify the intermediate (10-nm) filament proteins desmin from porcine myocardium and vimentin from porcine aorta, and to examine selected properties of both proteins. Desmin was prepared from the residue remaining after extraction of actomyosin from cardiac myofibrils. The desmin was solubilized with 8 M urea, and purified by batch chromatography in 6 M urea-containing solutions on DEAE cellulose and hydroxyapatite, followed by column chromatography on DEAE-Sepharose CL-6B. Vimentin was prepared from the tunica media of porcine aorta adjacent to the heart. The vimentin was solubilized with 8 M urea from the residue remaining after extraction of actomyosin from smooth muscle myofibrils. Final purification was achieved in 6 M urea-containing solutions by batch chromatography on DEAE cellulose, followed by column chromatography on hydroxyapatite and DEAE-Sepharose CL-6B. Circular dichroic spectra of both proteins indicated an alpha-helical content of about 41%. Both proteins existed as a major, and a slightly more acidic, minor isovariant. Amino acid analysis showed that cardiac desmin was similar in composition to other mammalian desmins. Aorta vimentin is similar in composition to vimentin isolated from other sources, but differs significantly from desmin. Desmin was localized at the Z-line and intercalated disc region of cardiac myofibrils by indirect immunofluorescence. Vimentin was localized in a filamentous pattern in vascular smooth muscle cells. At physiological pH and ionic strength, both proteins assembled into filaments similar in morphology to native 10-nm filaments, but there were significant differences in the solubility properties of the two proteins. At subphysiological ionic strength, vimentin was more soluble than desmin. Both proteins were more soluble at low ionic strength in the presence of a reducing agent. At physiological ionic strength, a reducing agent had little effect. At the same ionic strength, divalent cations were more effective than monovalent cations in promoting filament elongation. Mixtures of desmin and vimentin copolymerize to form heteropolymers with solubility properties and filament lengths intermediate between desmin and vimentin homopolymers. Decoration of the heteropolymers with desmin or vimentin antibodies showed that both proteins were distributed uniformly in the filaments

AutoCone: An OmniDirectional Robot for Lane-Level Cone Placement

This paper summarizes the progress in developing a rugged, low-cost, automated ground cone robot network capable of traffic delineation at lane-level precision. A holonomic omnidirectional base with a traffic delineator was developed to allow flexibility in initialization. RTK GPS was utilized to reduce minimum position error to 2 centimeters. Due to recent developments, the cost of the platform is now less than $1,600. To minimize the effects of GPS-denied environments, wheel encoders and an Extended Kalman Filter were implemented to maintain lane-level accuracy during operation and a maximum error of 1.97 meters through 50 meters with little to no GPS signal. Future work includes increasing the operational speed of the platforms, incorporating lanelet information for path planning, and cross-platform estimation

Online Multi Camera-IMU Calibration

Visual-inertial navigation systems are powerful in their ability to accurately estimate localization of mobile systems within complex environments that preclude the use of global navigation satellite systems. However, these navigation systems are reliant on accurate and up-to-date temporospatial calibrations of the sensors being used. As such, online estimators for these parameters are useful in resilient systems. This paper presents an extension to existing Kalman Filter based frameworks for estimating and calibrating the extrinsic parameters of multi-camera IMU systems. In addition to extending the filter framework to include multiple camera sensors, the measurement model was reformulated to make use of measurement data that is typically made available in fiducial detection software. A secondary filter layer was used to estimate time translation parameters without closed-loop feedback of sensor data. Experimental calibration results, including the use of cameras with non-overlapping fields of view, were used to validate the stability and accuracy of the filter formulation when compared to offline methods. Finally the generalized filter code has been open-sourced and is available online

Vehicular Teamwork: Collaborative localization of Autonomous Vehicles

This paper develops a distributed collaborative localization algorithm based on an extended kalman filter. This algorithm incorporates Ultra-Wideband (UWB) measurements for vehicle to vehicle ranging, and shows improvements in localization accuracy where GPS typically falls short. The algorithm was first tested in a newly created open-source simulation environment that emulates various numbers of vehicles and sensors while simultaneously testing multiple localization algorithms. Predicted error distributions for various algorithms are quickly producible using the Monte-Carlo method and optimization techniques within MatLab. The simulation results were validated experimentally in an outdoor, urban environment. Improvements of localization accuracy over a typical extended kalman filter ranged from 2.9% to 9.3% over 180 meter test runs. When GPS was denied, these improvements increased up to 83.3% over a standard kalman filter. In both simulation and experimentally, the DCL algorithm was shown to be a good approximation of a full state filter, while reducing required communication between vehicles. These results are promising in showing the efficacy of adding UWB ranging sensors to cars for collaborative and landmark localization, especially in GPS-denied environments. In the future, additional moving vehicles with additional tags will be tested in other challenging GPS denied environments

EXPLORING WHY EMERGING ADULTS ARE CHOOSING TO BELONG TO EMERGING CHURCHES:

This study explored why emerging adults in South Africa choose to belong to emerging churches. Emerging adulthood, encompassing the ages between 18 and 25, is a time marked by considering all available options before making choices that have long-lasting effects on the rest of a person’s life. Emerging adults are also making choices about where they attend church. During emerging adulthood, youth fall away from the church completely in the international phenomenon known as “the missing generation”. In South Africa, this is not the case. Emerging adults here walk away from the churches they grew up in to experiment with different kinds of churches. A local expression of the emerging church is fast-growing in South Africa, but it has not been researched thoroughly across academic spheres, indicating the value of this study. A Venn diagram approach highlights six points of overlap between emerging adults and these emerging churches, namely: spiritual, international, intergenerational, missional, hospitable, and multicultural. Both emerging adults and emerging churches are leading the way to a new way of doing and being church because they operate as agents of change wherever they are. This study gathered qualitative data through semi-structured interviews that were conducted with 21 emerging adult members of 4 emerging churches in Stellenbosch, to understand their experiences and expectations of church. The data obtained suggests that this generation of young believers is passionately committed to their churches and their faith and confirmed that the six points of overlap that the literature review identified are relevant. In their own way, they are figuring out how to live as faithfully as they can in their personal relationship with Jesus, which also propels them to desire a missional impact. The phenomenon that motivated this study is that emerging adults are often missing from mainline churches and experimenting with emerging churches instead. This study initiated a storytelling conversation with emerging adult members of emerging churches that offered valuable insights for how to be church for a future generation.Master

The Merle Beach school site (20Cl 275) : an assessment of the archaeology of rural mid-Michigan education during the nineteenth century and methods for it's examination

Thesis (M.A.)--Michigan State University. Department of Anthropology, 1998Includes bibliographical references (pages 166-169