Filter induced errors in laser anemometer measurements using counter processors

Simulations of laser Doppler anemometer (LDA) systems have focused primarily on noise studies or biasing errors. Another possible source of error is the choice of filter types and filter cutoff frequencies. Before it is applied to the counter portion of the signal processor, a Doppler burst is filtered to remove the pedestal and to reduce noise in the frequency bands outside the region in which the signal occurs. Filtering, however, introduces errors into the measurement of the frequency of the input signal which leads to inaccurate results. Errors caused by signal filtering in an LDA counter-processor data acquisition system are evaluated and filters for a specific application which will reduce these errors are chosen

Optimization of fringe-type laser anemometers for turbine engine component testing

The fringe type laser anemometer is analyzed using the Cramer-Rao bound for the variance of the estimate of the Doppler frequency as a figure of merit. Mie scattering theory is used to calculate the Doppler signal wherein both the amplitude and phase of the scattered light are taken into account. The noise from wall scatter is calculated using the wall bidirectional reflectivity and the irradiance of the incident beams. A procedure is described to determine the optimum aperture mask for the probe volume located a given distance from a wall. The expected performance of counter type processors is also discussed in relation to the Cramer-Rao bound. Numerical examples are presented for a coaxial backscatter anemometer

Laser anemometry for hot section applications

Laser anemometers (LA's) for use in the study of the hot section components of turbomachinery are being developed. Specifically, laser anemometers are being developed for use in the 50.8-cm (20-in.) diameter warm turbine and high-pressure turbine (HPT) facilities at Lewis. A brief review of the status of the program along with some preliminary data taken in an open-jet burner are presented

A digital optical torquemeter for high rotational speed applications

A digital optical torquemeter system designed for applications at high rotational speeds was fabricated and tested for zero stability at speeds up to 20,000 rpm. Data obtained in a spin rig and with simulated inputs demonstrate that the system is capable of measuring torque bar twist to within 0.03 degrees at speeds of 30,000 rpm. The optical system uses fiber optic bundles to transmit light to the torque bar and to silicon avalanche detectors. The system is microcomputer based and provides measurements of average torque and torque as a function of angular shaft position. The torquemeter requires no bearings or other contact between the rotating torque bar and the nonrotating optics, and tolerates movement of the torque bar as large as 1 mm relative to the optics

Comparison of the bidirectional reflectance distribution function of various surfaces

Described is the development and use of a system to measure the Bidirectional Reflectance Distribution Function (BRDF) of various surfaces. The BRDF measurements are used in the analysis and design of optical measurement systems, such as laser anemometers. An argon ion laser (514 nm) is the light source. Preliminary results are presented for eight samples: two glossy black paints, two flat black paints, black glass, sand blasted aluminum, unworked aluminum, and a white paint. A BaSO4 white reflectance standard was used as the reference sample throughout the tests. The reflectance characteristics of these surfaces are compared

Laser anemometers of hot-section applications

Laser anemometers are being developed for use in the turbine facilities at Lewis that are involved in the Turbine Engine Hot Section Technology Program. The status of the program is given along with some results accomplished since 1983

The role of the lissencephaly protein Pac1 during nuclear migration in budding yeast

During mitosis in Saccharomyces cerevisiae, the mitotic spindle moves into the mother–bud neck via dynein-dependent sliding of cytoplasmic microtubules along the cortex of the bud. Here we show that Pac1, the yeast homologue of the human lissencephaly protein LIS1, plays a key role in this process. First, genetic interactions placed Pac1 in the dynein/dynactin pathway. Second, cells lacking Pac1 failed to display microtubule sliding in the bud, resulting in defective mitotic spindle movement and nuclear segregation. Third, Pac1 localized to the plus ends (distal tips) of cytoplasmic microtubules in the bud. This localization did not depend on the dynein heavy chain Dyn1. Moreover, the Pac1 fluorescence intensity at the microtubule end was enhanced in cells lacking dynactin or the cortical attachment molecule Num1. Fourth, dynein heavy chain Dyn1 also localized to the tips of cytoplasmic microtubules in wild-type cells. Dynein localization required Pac1 and, like Pac1, was enhanced in cells lacking the dynactin component Arp1 or the cortical attachment molecule Num1. Our results suggest that Pac1 targets dynein to microtubule tips, which is necessary for sliding of microtubules along the bud cortex. Dynein must remain inactive until microtubule ends interact with the bud cortex, at which time dynein and Pac1 appear to be offloaded from the microtubule to the cortex

Child and Infant Mortality; Risk Factors Related to SUID in Marion County

poster abstractBetween 2003- 2012, Indiana had 434 child deaths, including 53 Sudden Unexpected Infant Death (SUID) cases. Marion County has a high rate of SUID at 14%. The purpose of our research is to identify the risk factors for suffocation and to determine if SUID can be better prevented. In a pilot exploratory study, we analyzed five de-identified Marion County SUID cases to identify the asphyxia variables. The Fetal Infant Mortality Review (FIMR) cases allowed for thematic analysis. We used a meta-aggregation program NOTARI (Narrative, opinion, text assessment, and review instrument) to focus on categorical variables. Results identified asphyxia variables such as swaddling, blanket suffocation, wedging, parents bedding, soft bedding with pillows. Common maternal variables were obesity, hypertension, and STDs. Infant variables included breathing problems and cardio-respiratory pathologies. We found four cases with documented safe sleep education. The education that parents receive on safe sleep is not a guarantee that they will practice safe sleep with their infants. The education might not be effective enough to help them comprehend its importance; therefore nurses and other healthcare professionals need to consider changing the way they educate and advocate for parents. We suggest the introduction of more primary educational programs that will help the community understand safe sleep and SUID. This intervention would help decrease the incidence of sudden unexpected infant death