Distribution and Population Status of Mussels in Eastern Montana: New Findings and Updates on Five Species East of the Divide

The first 2 yrs of the SWG state-wide mussel surveys focused on the western pearlshell, but we’ve also collected distributional and population data on five other mussel species occurring in the state, two native —fatmucket (Lampsilis siliquoidaea) and giant floater (Pyganodon grandis)— and three introduced species (black sandshell, mapleleaf and creek heelsplitter). Eastern Mussel Surveys in 2008 and 2009 focused on the Missouri, Milk, Marias and Yellowstone River Watersheds. Survey reaches were chosen opportunistically based on accessibility, previous mussel sightings and suitable mussel habitat (depositional areas and gravel run/glides). Aquascopes were used for shallow water transects, while SCUBA was utilized for deeper water (>1 m). Mussel data recorded during transects were standardized by time (CPUE, man-hour) and distance (mussels per 50 m). Rivers with excellent populations of native mussels include the Missouri River between Fort Benton and Fort Peck, the Marias River above Lake Elwell and within 10 mi of the confluence. In the Yellowstone River Watershed, the Tongue and Bighorn Rivers reported viable fatmucket populations, while catch rates of the fatmucket on the Yellowstone mainstem were low (avg. ~1/hr compared to ~7 /hr in the Missouri). We documented the first records of the giant floater in the Yellowstone Basin at three tributary sites (O’Fallon, Little Porcupine, Tongue River), but no evidence of this species in the mainstem. The introduced mapleleaf (Quadrula quadrula) has high densities in the Tongue River, but was not found live in the mainstem Yellowstone. Further population analysis and state conservation rank status will also be presented

Western Range Expansion of the Black Sandshell Mussel in Montana

Newly discovered populations of the black sandshell mussel (Ligumia recta) from the Missouri and Marias Rivers in east-central Montana extend the species known range to its farthest western point in the United States and North America (west of 110° longitude).  The black sandshell is an introduced mussel in Montana and has become common and abundant in the Missouri River drainage since its establishment in Fort Peck Reservoir in the 1940’s.  Despite the increased distribution of the black sandshell westward across the prairie rivers of Montana, elsewhere in their native range, the species is declining.  This is a species of conservation concern in 21 states.  Habitat conditions and host fish abundances that are allowing this species to thrive in Montana’s rivers might provide valuable information for the conservation needs of this species in native states where it is now in decline

Western Range Expansion of the Black Sandshell Mussel in Montana

Newly discovered populations of the black sandshell mussel (Ligumia recta) from the Missouri and Marias Rivers in east-central Montana extend the species known range to its farthest western point in the United States and North America (west of 110° longitude).  The black sandshell is an introduced mussel in Montana and has become common and abundant in the Missouri River drainage since its establishment in Fort Peck Reservoir in the 1940’s.  Despite the increased distribution of the black sandshell westward across the prairie rivers of Montana, elsewhere in their native range, the species is declining.  This is a species of conservation concern in 21 states.  Habitat conditions and host fish abundances that are allowing this species to thrive in Montana’s rivers might provide valuable information for the conservation needs of this species in native states where it is now in decline

Analysis of simple 2-D and 3-D metal structures subjected to fragment impact

Theoretical methods were developed for predicting the large-deflection elastic-plastic transient structural responses of metal containment or deflector (C/D) structures to cope with rotor burst fragment impact attack. For two-dimensional C/D structures both, finite element and finite difference analysis methods were employed to analyze structural response produced by either prescribed transient loads or fragment impact. For the latter category, two time-wise step-by-step analysis procedures were devised to predict the structural responses resulting from a succession of fragment impacts: the collision force method (CFM) which utilizes an approximate prediction of the force applied to the attacked structure during fragment impact, and the collision imparted velocity method (CIVM) in which the impact-induced velocity increment acquired by a region of the impacted structure near the impact point is computed. The merits and limitations of these approaches are discussed. For the analysis of 3-d responses of C/D structures, only the CIVM approach was investigated

Two-dimensional finite-element analyses of simulated rotor-fragment impacts against rings and beams compared with experiments

Finite element modeling alternatives as well as the utility and limitations of the two dimensional structural response computer code CIVM-JET 4B for predicting the transient, large deflection, elastic plastic, structural responses of two dimensional beam and/or ring structures which are subjected to rigid fragment impact were investigated. The applicability of the CIVM-JET 4B analysis and code for the prediction of steel containment ring response to impact by complex deformable fragments from a trihub burst of a T58 turbine rotor was studied. Dimensional analysis considerations were used in a parametric examination of data from engine rotor burst containment experiments and data from sphere beam impact experiments. The use of the CIVM-JET 4B computer code for making parametric structural response studies on both fragment-containment structure and fragment-deflector structure was illustrated. Modifications to the analysis/computation procedure were developed to alleviate restrictions

Experimental transient and permanent deformation studies of steel-sphere-impacted or explosively-impulsed aluminum panels

The sheet explosive loading technique (SELT) was employed to obtain elastic-plastic, large deflection 3-d transient and/or permanent strain data on simple well defined structural specimens and materials: initially-flat 6061-T651 aluminum panels with all four sides ideally clamped via integral construction. The SELT loading technique was chosen since it is both convenient and provides "forcing function information" of small uncertainty. These data will be useful for evaluating pertinent 3-d structural response prediction methods

User's guide to computer programs JET 5A and CIVM-JET 5B to calculate the large elastic-plastic dynamically-induced deformations of multilayer partial and/or complete structural rings

These structural ring deflections lie essentially in one plane and, hence, are called two-dimensional (2-d). The structural rings may be complete or partial; the former may be regarded as representing a fragment containment ring while the latter may be viewed as a 2-d fragment-deflector structure. These two types of rings may be either free or supported in various ways (pinned-fixed, locally clamped, elastic-foundation supported, mounting-bracket supported, etc.). The initial geometry of each ring may be circular or arbitrarily curved; uniform-thickness or variable-thickness rings may be analyzed. Strain-hardening and strain-rate effects of initially-isotropic material are taken into account. An approximate analysis utilizing kinetic energy and momentum conservation relations is used to predict the after-impact velocities of each fragment and of the impact-affected region of the ring; this procedure is termed the collision-imparted velocity method (CIVM) and is used in the CIVM-JET 5 B program. This imparted-velocity information is used in conjunction with a finite-element structural response computation code to predict the transient, large-deflection, elastic-plastic responses of the ring. Similarly, the equations of motion of each fragment are solved in small steps in time. Provisions are made in the CIVM-JET 5B code to analyze structural ring response to impact attack by from 1 to 3 fragments, each with its own size, mass, translational velocity components, and rotational velocity. The effects of friction between each fragment and the impacted ring are included

Cap And Trade Allowance Accounting: A Divergence Between Theory And Practice

This study concerns one of the most significant and glaring divergences between theory and practice that has emerged since the accounting discipline’s conceptual framework was developed in the late 1970s.  Through an extensive empirical examination of extant practices with respect to cap and trade allowances allotted to U.S. electric utilities under the Clean Air Act Amendments of 1990, this research demonstrates a surprising—and possibly unsupportable—divergence between expected and actual practice.  The results of this research show that practice and theory diverge in a substantial and negative way.  EPA-issued emissions allowances meet the accepted definition of an economic resource that will provide a future benefit, i.e., an asset.  Yet, examination of five years’ of public financial disclosures for the entities affected by the CAAA shows scant recognition for the acquisition, disposition, or year-end existence of these tradable emissions permits.  Financial statement users and other stakeholders of the affected entities may be seriously misled by the failure to recognize the allowances.  This divergence between theory and practice does not appear to be justifiable