The Tant-Frost Debate on the Organ and Society Work in the Church of Christ

https://digitalcommons.acu.edu/crs_books/1052/thumbnail.jp

KINETIC AND KINEMATIC CHARACTERISTICS OF IMPACTS FROM VARIOUS HEIGHTS EXPERIENCED BY CHILDREN

In 1977, the United States Consumer Product Safety Commission reported treatment of93,000 children in emergency rooms for injuries sustained on playgrounds. By 1986, the number had risen to over 200,000 and 70 percent ofthese cases were falls from equipment onto various play surfaces (U.S. Consumer Product Safety Commission, 1986). In addition to free play activities, today's youth are also experiencing acute injuries from single impact trauma during organized sports (Micheli, 1986)

Smith-Tant Debate on Campbell\u27s Baptism : Was Alexander Campbell Baptized In Order to Obtain Remission of Sins?

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The Gospel X-Ray

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Stream nutrient enrichment has a greater effect on coarse than on fine benthic organic matter

Author Posting. © Society for Freshwater Science, 2013. This article is posted here by permission of Society for Freshwater Science for personal use, not for redistribution. The definitive version was published in Freshwater Science 32 (2013): 1111-1121, doi:10.1899/12-049.1.Nutrient enrichment affects bacteria and fungi associated with detritus, but little is known about how biota associated with different size fractions of organic matter respond to nutrients. Bacteria dominate on fine (1 mm) fractions, which are used by different groups of detritivores. We measured the effect of experimental nutrient enrichment on fungal and bacterial biomass, microbial respiration, and detrital nutrient content on benthic fine particulate organic matter (FPOM) and coarse particulate organic matter (CPOM). We collected FPOM and CPOM from 1 reference and 1 enriched stream. CPOM substrates consisted of 2 litter types with differing initial C:nutrient ratios (Acer rubrum L. and Rhododendron maximum L.). Fungal and bacterial biomass, respiration, and detrital nutrient content changed with nutrient enrichment, and effects were greater on CPOM than on FPOM. Fungal biomass dominated on CPOM (99% total microbial biomass), whereas bacterial biomass dominated on FPOM (95% total microbial biomass). These contributions were unchanged by nutrient enrichment. Bacterial and fungal biomass increased more on CPOM than FPOM. Respiration increased more on CPOM (up to 300% increase) than FPOM (50% increase), indicating important C-loss pathways from these resources. Microbial biomass and detrital nutrient content were positively related. Greater changes in nutrient content were observed on CPOM than on FPOM, and changes in detrital C:P were greater than changes in detrital C:N. Threshold elemental ratios analyses indicated that enrichment may reduce P limitation for shredders and exacerbate C limitation for collector-gatherers. Changes in CPOM-dominated pathways are critical in predicting shifts in detrital resource quality and C flow that may result from nutrient enrichment of detritus-based systems.This study and preparation of this manuscript were supported by National Science Foundation grants DEB-0318063 (to ADR, K. Suberkropp, B. Wallace, and M. Black) and DEB-0918894 (to ADR, J. Benstead, V. Gulis, and J. Maerz) and an Odum School of Ecology Graduate Research grant to CJT.2014-09-1

SEGMENTALCOORDINATIONAND TEMPORAL STRUCTURE OF THE VOLLEYBALL PIKE

In the game ofvol1eyball, the spike is one ofthe most difficult and demanding techniques to master. The athlete is expect4ed to jump and hit a ball with maximum force and accuracy at the approximate peak of the jump. Prsala (1982) identified four phases in the analysis of the spike: the approach, preparation, hitting, and landing. The approach involves t 0 or three controlled running strides, a transitional last step to prepare for the transfer ofhorizontal momentum to vertical momentum, and a two foot vertical jump. In the preparatory phase the striking arm is swung upward in an abduct d and laterally rotated position. The elbow is fle ed at approximately 90 degrees and the wrist hyperextended. During the hitting phase, the shoulder is elevated; the upper arm is inwardly rotated and a ducted; the forearm is extended at the elbow and the wrist is flexed. The athl te absorbs the downward momentum by flexing the joints of the lower extremities when landing

Effective Grain Orientation Mapping of Complex and Locally Anisotropic Media for Improved Imaging in Ultrasonic Non-Destructive Testing

Imaging defects in austenitic welds presents a significant challenge for the ultrasonic non-destructive testing community. Due to the heating process during their manufacture, a dendritic structure develops, exhibiting large grains with locally anisotropic properties which cause the ultrasonic waves to scatter and refract. When basic imaging algorithms, which typically make constant wave speed assumptions, are applied to datasets arising from the inspection of these welds, the resulting defect reconstructions are often distorted and difficult to interpret correctly. However, knowledge of the underlying spatially varying material properties allows correction of the expected wave travel times and thus results in more reliable defect reconstructions. In this paper, an approximation to the underlying, locally anisotropic structure of the weld is constructed from ultrasonic time of flight data. A new forward model of wave front propagation in locally anisotropic media is presented and used within the reversible-jump Markov chain Monte Carlo method to invert for the map of effective grain orientations across different regions of the weld. This forward model and estimated map are then used as the basis for an advanced imaging algorithm and the resulting defect reconstructions exhibit a significant improvement across multiple flaw characterization metrics

A spectral method for sizing cracks using ultrasonic arrays

Ultrasonic phased array systems are becoming increasingly popular as tools for the inspection of safety-critical structures within the non-destructive testing industry. The datasets captured by these arrays can be used to image the internal structure of individual components, allowing the location and nature of any defects to be deduced. Although there exist strict procedures for measuring defects via these imaging algorithms, sizing flaws which are smaller than two wavelengths in diameter can prove problematic and the choice of threshold at which the defect measurements are made can introduce an aspect of subjectivity. This paper puts forward a completely objective approach specific to cracks based on the Kirchhoff scattering model and the approximation of the resulting scattering matrices by Toeplitz matrices. A mathematical expression relating the crack size to the maximum eigenvalue of the associated scattering matrix is derived. Analysis of this approximation shows that the method will provide a unique crack size for a given maximum eigenvalue whilst providing a quick calculation method which avoids the need to numerically generate model scattering matrices (the computation time is up to 10^3 times faster). A sensitivity analysis demonstrates that the method is most effective for sizing defects that are commensurate with or smaller than the wavelength of the ultrasonic wave. The method is applied to simulated FMC data arising from finite element calculations where the crack length to wavelength ratios range between 0.6 and 1.9. The recovered objective crack size exhibits an error of 12%

The detection of flaws in austenitic welds using the decomposition of the time reversal operator

The non-destructive testing of austenitic welds using ultrasound plays an important role in the assessment of the structural integrity of safety critical structures. The internal microstructure of these welds is highly scattering and can lead to the obscuration of defects when investigated by traditional imaging algorithms. This paper proposes an alternative objective method for the detection of flaws embedded in austenitic welds based on the singular value decomposition of the time-frequency domain response matrices. The distribution of the singular values is examined in the cases where a flaw exists and where there is no flaw present. A lower threshold on the singular values, specific to austenitic welds, is derived which, when exceeded, indicates the presence of a flaw. The detection criterion is successfully implemented on both synthetic and experimental data. The datasets arising from welds containing a flaw, are further interrogated using the decomposition of the time reversal operator (DORT) method and the total focussing method (TFM) and it is shown that images constructed via the DORT algorithm typically exhibit a higher signal to noise ratio than those constructed by the TFM algorithm

A Maximum Eigenvalue Approximation for Crack-Sizing Using Ultrasonic Arrays

Ultrasonic phased array systems are becoming increasingly popular as tools for the inspection of safety-critical structures with in the non-destructive testing industry. The datasets captured by these arrays can be used to image the internal microstructure of individual components, all owing the location and nature of any defects to be deduced. Unfortunately, many of the current imaging algorithms require an arbitrary threshold at which the defect measurements can be taken and this aspect of subjectivity can lead to varying characterisations of a flaw between different operators. This paper puts forward an objective approach based on the Kirchoff scattering model and the approximation of the resulting scattering matrices by Toeplitz matrices. A mathematical expression relating the crack size to the maximum eigenvalue of the associated scattering matrix is thus derived. The formula is analysed numerically to assess its sensitivity to the system parameters and it is shown that the method is most effective for sizing defects that are commensurate with the wavelength of the ultrasonic wave (or just smaller than. The method is applied to simulated FMC data arising from finite element calculations where the crack length to wavelength ratios range between 0.6 and 1.8. The recovered objective crack size exhibits an error of 12%