Survey: Evidence

Twenty-one years ago Chief Justice Earl Warren appointed an advisory committee to propose evidentiary rules for the federal courts, thus beginning a movement which has worked a minor revolution in substantive evidence law

Oscillations of Dynamic Topography in the Eastern Equatorial Pacific

For 14 months in 1980–81, surface dynamic height was monitored with inverted echo sounders at five sites from 0 to 9°N along 110°W. These records show that the SEC/NECC equatorial current system was well-developed during the boreal summer and fall, but weak and irregular during winter and spring when westward flow associated with the NEC extended as far south as 6°N. Superimposed on the mean dynamic topography of this region are energetic 20-to-80-day oscillations, longer periods being associated with higher latitudes. Near the equatorial ridge (∼5°N), these oscillations have predominantly monthly periods, and amplitude of ∼10 dyn cm comparable to the mean dynamic-height difference across the NECC. The broad in-phase meridional extent of these monthly oscillations implies that the principal mode of ridge variation is vertical undulation rather than meridional meandering, producing large in-phase monthly modulations in transport of the SEC and NECC. Oscillations or the equatorial ridge are correlated with propagating ∼1000-km wavelength sea surface temperature (SST) wave patterns observed in satellite infrared imagery. Passage of a northerly SST crest on the equatorial front at 110°W corresponds to a dynamic height minimum on the equatorial ridge. The relative phase and trochoidal shape of these crests is explained kinematically by superposition of the observed mean and oscillatory dynamic-height fields

Loss Factor Estimation Using the Impulse Response Decay Method on a Stiffened Structure

High-frequency vibroacoustic modeling is typically performed using energy-based techniques such as Statistical Energy Analysis (SEA). Energy models require an estimate of the internal damping loss factor. Unfortunately, the loss factor is difficult to estimate analytically, and experimental methods such as the power injection method can require extensive measurements over the structure of interest. This paper discusses the implications of estimating damping loss factors using the impulse response decay method (IRDM) from a limited set of response measurements. An automated procedure for implementing IRDM is described and then evaluated using data from a finite element model of a stiffened, curved panel. Estimated loss factors are compared with loss factors computed using a power injection method and a manual curve fit. The paper discusses the sensitivity of the IRDM loss factor estimates to damping of connected subsystems and the number and location of points in the measurement ensemble

Theoretical study of the performance of piles.

Well proven numerical techniques of analysis have been used to study the manner in which piled foundations deform under working loads. It has been assumed that the soil surrounding the piles may be characterised by suitably chosen elastic constants. This assumption has enabled simple models of the behaviour of single piles under the action of vertical and horizontal loads, to be established; the models have led to more efficient and economic methods of estimating the likely deformation of working piles, and an improved understanding of the manner in which load is transferred from pile to soil. The mode ls for the behaviour of single piles have been extended for the analysis of pile groups by studying the deformation patterns in the soil around a loaded pile. The solutions developed have been extensively checked to ensure that they agree with the results of more sophisticated, computer oriented( analyses, and also that they are consistent with the results of model and full-scale pile tests. An attempt has been made, towards the end of the thesis, to estimate the disturbance due to the installation of a pile, particularly as regards the generation of excess pore pressures and the subsequent consolidation

The scanning electron microscope as an accelerator for the undergraduate advanced physics laboratory

Few universities or colleges have an accelerator for use with advanced physics laboratories, but many of these institutions have a scanning electron microscope (SEM) on site, often in the biology department. As an accelerator for the undergraduate, advanced physics laboratory, the SEM is an excellent substitute for an ion accelerator. Although there are no nuclear physics experiments that can be performed with a typical 30 kV SEM, there is an opportunity for experimental work on accelerator physics, atomic physics, electron‐solid interactions, and the basics of modern e‐beam lithography.National Science Foundation (U.S.) (Grant 0823778

The influence of incorporating a forecutter on the performance of offshore pipeline ploughs

AbstractInstallation of offshore pipelines in the seabed can be efficiently achieved using pipeline ploughs. Increased efficiency may be achievable through incorporating a smaller forecutter in advance of the main plough share. Currently guidance is limited and conflicting as to the advantages or disadvantages of incorporating a forecutter. To investigate the effect of forecutter inclusion model tests were undertaken at 1/50th scale under laboratory conditions in sand beds prepared at different relative densities in both dry and saturated conditions. Dry sand tests were used to determine the effect of the forecutter on the static or passive components of plough tow force. The currently adopted passive pressure coefficient (Cs) did not appear to vary with relative density to the same degree as previously suggested and the forecutter increased the magnitude of the passive or static resistance to ploughing. Saturated tests were used to determine the effects of the forecutter on the rate dependant component of ploughing resistance and allow verification of a dimensionless form of rate effect representation. The forecutter acts to reduce the rate effect component of plough tow force in both fine sand (low permeability) and to a lesser extent in medium sand (higher permeability). In fine and silty sands, however, incorporating a forecutter would seem highly beneficial at all ploughing depths and soil densities but in medium sand (higher permeability) the benefits of incorporation are limited to an operating window at shallower trench depths and lower relative density

Fundamental‐mode basin oscillations in the Japan/East Sea

We present observational evidence from coastal tide station and bottom pressure data that basin‐mode oscillations are frequently excited in the Japan/East Sea (JES). The fundamental basin‐mode is a Kelvin‐wave‐like oscillation consisting of a single amphidromic system around which the high water propagates counter‐clockwise. Its period is about 6.7 hours and its coastal wavelength is equivalent to the circumference of the JES. The relative amplitudes of the observed oscillations agree with Rikiishi\u27s 1986 model results except for stations near the Korea Strait where the closed boundary in the model produces unrealistically high amplitudes. The basin oscillation amplitude varies on synoptic time scales (2–17 days) and exhibits seasonal variations. The optimal wind direction to generate basin‐mode oscillations is along 60°/240° T

Big sagebrush (Artemisia tridentata) ecology and management with emphasis on prescribed burning

Four studies were conducted. First, mountain big sagebrush communities were burned at Lava Beds National Monument, California, and The Crooked River National Grassland, Oregon. In two years at Lava Beds, basal cover of Idaho fescue in one community and Thur- ber's needlegrass in one of three communities did not recover. Basal cover of bluebunch wheatgrass and Sandberg's bluegrass re- covered or increased above prefire levels at the expense of Idaho fescue and Thurber's needlegrass. Bunchgrasses recovery was based on height and production which increased to equal or exceed prefire levels. At Crooked River, height and production of bluebunch wheat- grass were much higher than prefire levels, but basal cover remain- ed extremely low after two years. Prescribed burning recommenda- tions were presented. Secondly, after hot and cool in situ propane barrel burns, mountain big sagebrush seed emergence in the greenhouse was stimu- lated. Basin big sagebrush seed emergence was reduced by both fire intensities. Emergence was inverse to fire intensity for both sub- species. Wyoming big sagebrush was not affected by fire. Both in- tensities reduced emergence of most herbaceous species from mountain big sagebrush dominated soils. Hot fires were required to reduce emergence of the few herbaceous species affected by fire on basin and especially Wyoming big sagebrush dominated soils. A trend of in- creasing fire resistance with increasing site severity was evident. Thirdly, individual and area fuel loading equations were de- veloped for each component of fuel of the three subspecies of big sagebrush. R² values for individual shrub equations ranged from .36 to .96. Line intercept cover, the number, and the height of intercepted shrubs were used to estimate area fuel loadings with R² values ranging from .42 to .84. This method of estimating area fuel loading provides relatively high precision at reduced cost. Fourthly, basal cover and leaf length or plant height were used to estimate bunchgrass production. R² values for burned plant equations were higher (.66-.87) than R² values for unburned- ungrazed plant equations (.35-.85). Basal cover accounted for at least 70 percent of the variation in Thurber's needlegrass, burned Idaho fescue, and burned bluebunch wheatgrass production. Comparisons based on indirect estimation yielded results comparable to clipping

An evaluation of the respiratory health status of automotive spray-painters exposed to paints containing hexamethylene di-isocyanates in the greater Durban area

No Abstract