1,237 research outputs found

    Noise reduction studies for the OV-1 airplane

    Get PDF
    A study has been conducted to define possible modifications to the OV-1 aircraft to reduce its aural detection distance. This effort involved documenting the noise characteristics of the airplane, devising modifications to reduce the noise, estimating the reduction in detection distance, and evaluating aircraft performance as a result of these modifications. It was found that the main noise source on this aircraft is the propeller and hence modifications only to the propeller and the propeller drive system are proposed. Modifications involving only the propeller are noted to involve no increase in weight but they result in only a modest decrease in aural detection distance. In order to obtain substantial decreases in aural detection distance, modifications involving changes both to the propeller and the engine-propeller gearing are required

    System for measuring passenger reaction to transportation-vehicle vibration

    Get PDF
    Equipment is capable of measuring frequencies from 0 to 50 Hz and is portable, light, inexpensive, and easily adaptable to field operations. System could be used in situations where it is necessary to record simultaneously subject response to other types of physical measurement or stimuli, such as temperature, noise, or pressure

    Tidal Flushing Restores the Physiological Condition of Fish Residing in Degraded Salt Marshes

    Get PDF
    Roads, bridges, and dikes constructed across salt marshes can restrict tidal flow, degrade habitat quality for nekton, and facilitate invasion by non-native plants including Phragmites australis. Introduced P. australis contributes to marsh accretion and eliminates marsh surface pools thereby adversely affecting fish by reducing access to intertidal habitats essential for feeding, reproduction, and refuge. Our study assessed the condition of resident fish populations (Fundulus heteroclitus) at four tidally restricted and four tidally restored marshes in New England invaded by P. australis relative to adjacent reference salt marshes. We used physiological and morphological indicators of fish condition, including proximate body composition (% lipid, % lean dry, % water), recent daily growth rate, age class distributions, parasite prevalence, female gravidity status, length-weight regressions, and a common morphological indicator (Fulton’s K) to assess impacts to fish health. We detected a significant increase in the quantity of parasites infecting fish in tidally restricted marshes but not in those where tidal flow was restored to reduce P. australis cover. Using fish length as a covariate, we found that unparasitized, non-gravid F. heteroclitus in tidally restricted marshes had significantly reduced lipid reserves and increased lean dry (structural) mass relative to fish residing in reference marshes. Fish in tidally restored marshes were equivalent across all metrics relative to those in reference marshes indicating that habitat quality was restored via increased tidal flushing. Reference marshes adjacent to tidally restored sites contained the highest abundance of young fish (ages 0–1) while tidally restricted marshes contained the lowest. Results indicate that F. heteroclitus residing in physically and hydrologically altered marshes are at a disadvantage relative to fish in reference marshes but the effects can be reversed through ecological restoration

    DEVELOPMENT OF pH AND TEMPERATURE OSCILLATIONS IN WATER CONTAINING ZnC03 CRYSTALLITES USING INTENTION IMPRINTED ELECTRONIC DEVICES

    Get PDF
    In this experimental study, two vessels, A and B, of pure water containing 0.4 wt. % sparingly soluble, small ZnC03 crystallites were positioned about 150 feet apart in separate buildings. An Intention Imprinted Electronic Device (lIED) was placed one foot from A. Both pH and temperature were monitored at B. Turning on the lIED at A led to the appearance of both short period (about one hour) and long period (about one day) pH-oscillations at location B plus a marked downward decline of the pH in the direction of the lIED intention. In one experiment, the pH declined a full pH unit in accord with the imprinted intention. In another experiment, shaking the vessel at B to redisperse the fine particles when the lIED was operating at A led to a fall in pH but plateauing somewhat short of the final pH as well as the reappearance of the short period oscillations. For control solutions with no present, no such pH behavior occurred

    A conceptual framework to assess the impact of training on equipment cost and availability in the military context

    Get PDF
    Designing military support is challenging and current practices need to be reviewed and improved. This paper gives an overview of the Industry current practices in designing military support under Ministry of Defence/Industry agreements (in particular for Contracting for Availability (CfA)), and identifies challenges and opportunities for improvement. E.g. training delivery was identified as an important opportunity for improving the CfA in-service phase. Thus, an innovative conceptual framework is presented to assess the impact of training on the equipment availability and cost. Additionally, guidelines for improving the current training delivery strategies are presented, which can also be applied to other Industry contexts

    Noise measurement evaluations of various takeoff-climbout profiles of a four-engine turbojet transport airplane

    Get PDF
    Noise measurement evaluations of various takeoff-climbout profiles of four engine turbojet transport airplan

    Combustion stability limits of coflowing turbulent jet diffusion flames

    Full text link
    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76288/1/AIAA-1988-538-444.pd

    Ecology of Phragmites australis and responses to tidal restoration

    Get PDF
    Tidal Marsh Restoration provides the scientific foundation and practical guidance necessary for coastal zone stewards to initiate salt marsh tidal restoration programs. The book compiles, synthesizes, and interprets the current state of knowledge on the science and practice of salt marsh restoration, bringing together leaders across a range of disciplines in the sciences (hydrology, soils, vegetation, zoology), engineering (hydraulics, modeling), and public policy, with coastal managers who offer an abundance of practical insight and guidance on the development of programs. The book is an essential work for managers, planners, regulators, environmental and engineering consultants, and others engaged in planning, designing, and implementing projects or programs aimed at restoring tidal flow to tide-restricted or diked salt marshes.https://scholarworks.wm.edu/asbookchapters/1065/thumbnail.jp

    Predicting Autism over Large-Scale Child Dataset

    Get PDF
    Data Analytics and Machine learning in healthcare are one of the most emerging and needed fields in current time. Also, a lot of research has been performed and is still being done in this field. In healthcare, gone are those days when only doctor examines and patient listens. Now doctor has a lot of technologies which can assist him and help in accurately diagnosing the disease with which his patient is suffering. The backbone of such technologies is data analytics and machine learning where we can make out a lot of inferences from tons of patientsβ€Ÿ data already available. This project aims at performing research and implementation of big data and machine learning techniques on the data related to the patients suffering from the disease called Autism. Autism is a neural disorder disease characterized by impaired social communication, verbal and non-verbal interaction, restrictive and repetitive behavior [4]. Autism is majorly noticed in children under or about the age of two years. One very important thing to be observed here is that autism is highly heritable and the cause includes both environmental factors and genetic susceptibility. Hence it is very important to have such data which contains details of patients including their symptoms, lab test data, history, vaccination details etc. which gives specific details of patients and their history. The project ultimately aims at training the data model with the set of training data and then testing and evaluating the data model using the test data. In this way, it should be a research and solution for implementing machine learning to detect and diagnose autism
    • …
    corecore