Experimental determination of dynamic Young's modulus and mechanical damping,and theoretical prediction of dislocation density for depleted uranium-0.75 wt% titanium using the PUCOT

Dynamic Young's modulus (E) and mechanical damping (Q ^–1) measurements were made for three microstructures (, + , and ) of a depleted uranium-0.75 wt% titanium alloy. The temperature range covered was 298 to 1123 K. The apparatus was the piezoelectric ultrasonic composite oscillator technique (PUCOT) operated at 80 kHz. The ranges of values for E and Q ^–1 were 193 to 99 GPa and 3×10^–3 to 8×10^–2, respectively. Correlations for E of each heat treatment as functions of temperature are presented. In addition, the mechanical damping against strain amplitude plots generated from PUCOT data were analysed using the Granato-Luecke zero Kelvin and high-temperature theories of dislocation damping. Computed dislocation densities ranged up to 10¹⁶m^–2.     

Long-term socioeconomic outcome following surgical intervention in the treatment of refractory epilepsy in childhood and adolescence

Surgical treatment of refractory epilepsy in childhood and adolescence has been shown to be effective in reducing the seizure frequency. This paper examines the question: "Does this result in a better socioeconomic outcome in later years?" Patients who underwent a surgical procedure for the treatment of their medically refractory epilepsy at our hospital, had more than 2-years' follow-up, and were less than 18 years old at time of survey were included. From a retrospective chart review, age at onset and at surgery, duration of seizures prior to surgery, years of follow-up, type of surgery, and neurological status were obtained. From a telephone survey, seizure frequency after surgery, marital, financial and driving status, level of education, and employment status were ascertained. Sixty-four patients in our epileptic surgical series meet entry criteria. Significantly higher levels of education, employment status and independence were found in patients with a class I Engel outcome compared to other Engel outcomes.     

An Application of a Large-Image Memory Graphics Workstation

One company solved its need for a workstation capable of 3-D plant design by creating its own highly interactive graphics hardware and software in a multiple-bus architecture.     

Carrier fringe analysis algorithms for three degree of freedom optical probing

In this work, we present a fiber-delivered and fiber-detected, 3-DOF optical probe concept for measuring optical components to be used in conjunction with an optical coordinate measuring machine (OCMM). The optical probe uses a Michelson interferometer to produce carrier fringes and a high density fiber bundle to transmit interferograms that are recorded away from the probe head in a remote imaging system. We compare several different signal FFT processing techniques (parabolic interpolation, windowing, and zero padding) and a single-bin DFT technique to compute and enhance the resolution of the displacement, tip, and tilt of a moving mirror. We simulated varying signal-to-noise ratios and interference fringe contrast ranges to determine the algorithms’ sensitivity to those parameters and compare our simulated values to measured SNR and fringe values. Based on this work, it should be possible to use a carrier fringe algorithm for fiber probing applications if the interferogram can be transmitted through the fiber bundle with sufficient contrast (40%) and SNR (30 dB).     

Calcite Prisms from Mollusk Shells (Atrina Rigida): Swiss‐cheese‐like Organic–Inorganic Single‐crystal Composites

Biogenic single‐crystal composites, such as sea urchin spines and calcitic prisms from mollusk shells, contain organic macromolecules inside of inorganic single‐crystal matrices. The nanoscale internal structure of these materials, however, is poorly understood, especially how the biomacromolecules are distributed within the crystals without significantly disrupting the crystalline lattice. Here, annular dark‐field scanning transmission electron microscopy and electron tomography reveal, in three dimensions, how biomacromolecules are distributed within the calcitic prisms from Atrina rigida shells. Disk‐like nanopatches, whose scattering intensity is consistent with organic inclusions, are observed to be anisotropically arranged within a continuous, single‐crystalline calcite matrix. These nanopatches are preferentially aligned with the (000l) planes of calcite. Along the crystallographic c‐axis, there are alternating organic‐rich and ‐poor regions on a length scale of tens of nanometers, while, in the ab plane, the distribution of nanopatches is more random and uniform. The structural features elucidated in this work have relevance to understanding the structure–property relationships and formation mechanisms of biominerals, as well as to the development of bio‐inspired strategies to extrinsically tune the properties of single‐crystals.     

Combined hardware and software aspects of reliability

This paper presents the similarities and differences between hardware, software and system reliability. Relative contributions to system failures are shown for software and hardware and failure and recovery propensities are also discussed. Reliability, availability and maintainability (RAM) concepts have been broadly developed for software reliability than hardware reliability. Extending these software concepts to hardware and system reliability helps in examining the reliability of complex systems. The paper concludes with assurance techniques for defending against faults. Most of the techniques discussed originate in software reliability but apply to all aspects of a system. Also, the effects of redundancy on overall system availability are shown.     

A durable chronic unit recording device with movable microelectrode

The design of a durable chronic unit recording device with movable microelectrode suitable for cats and monkeys is presented. Sufficiently rugged to remain on cats for weeks during exploration of a single electrode tract, the device also features: choice of stereotaxic coordinates over a large horizontal area at recording time; good stereotaxic precision; capability to hold a single unit for days; excellent insulation between the recording circuit and the animal; and simplicity of design and materials which allows fabrication of numerous devices in one lab.     

Effects of cold and compression dressings on early postoperative outcomes for the arthroscopic anterior cruciate ligament reconstruction patient

Efforts to minimize the morbidity of anterior cruciate ligament (ACL) reconstruction include the use of cryotherapy and/or compressive dressings in the immediate postoperative period. We undertook the present study to determine if the alleged benefits of the Cryo/Cuff, which combines these modalities, are more attributable to its compressive effect rather than cold application. Seventy-eight patients admitted for primary endoscopic ACL reconstruction using a bone-patella tendon-bone autograft were randomized to receive Cryo/Cuff compressive dressings postoperatively. Forty subjects (Group 1) had the cuff applied with continuous circulating ice water using the Autochill device, while 38 others (Group 2) received the cuff with room temperature water. Cases were performed as inpatients and all subjects were administered intravenous morphine postoperatively via a patient-controlled infusion pump for the first 24 postoperative hours. At baseline, the groups were well matched in age, sex, duration of symptoms, operative time, and associated meniscal surgery. No significant difference between groups was detected with respect to length of hospitalization, Hemovac knee drainage, oral and intravenous narcotic requirement, or subjective pain as measured by a visual analog scale. No apparent complications related to the use of the Cryo/Cuff dressings were noted. The clinical effect of the Cryo/Cuff in this study was not influenced by the use of continuous ice water vs. room temperature water. Further study should focus on variations in compression to evaluate the clinical impact of this device.