1,853 research outputs found
Evidence for parallel elongated structures in the mesosphere
The physical cause of partial reflection from the mesosphere is of interest. Data are presented from an image-forming radar at Brighton, Colorado, that suggest that some of the radar scattering is caused by parallel elongated structures lying almost directly overhead. Possible physical sources for such structures include gravity waves and roll vortices
Real-time atmospheric absorption spectra for in-flight tuning of an airborne dial system
Real-time measurements of atmospheric absorption spectra are displayed and used to precisely calibrate and fix the frequency of an Alexandrite laser to specific oxygen absorption features for airborne Differential Absorption Lidar (DIAL) measurements of atmospheric pressure and temperature. The DIAL system used contains two narrowband tunable Alexandrite lasers: one is electronically scanned to tune to oxygen absorption features for on-line signals while the second is used to obtain off-line (nonabsorbed) atmospheric return signals. The lidar operator may select the number of shots to be averaged, the altitude, and altitude interval over which the signals are averaged using single key stroke commands. The operator also determines exactly which oxygen absorption lines are scanned by comparing the line spacings and relative strengths with known line parameters, thus calibrating the laser wavelength readout. The system was used successfully to measure the atmospheric pressure profile on the first flights of this lidar, November 20, and December 9, 1985, aboard the NASA Wallops Electra aircraft
Airborne Lidar measurements of the atmospheric pressure profile with tunable Alexandrite lasers
The first remote measurements of the atmospheric pressure profile made from an airborne platform are described. The measurements utilize a differential absorption lidar and tunable solid state Alexandrite lasers. The pressure measurement technique uses a high resolution oxygen A band where the absorption is highly pressure sensitive due to collision broadening. Absorption troughs and regions of minimum absorption were used between pairs of stongly absorption lines for these measurements. The trough technique allows the measurement to be greatly desensitized to the effects of laser frequency instabilities. The lidar system was set up to measure pressure with the on-line laser tuned to the absorption trough at 13147.3/cm and with the reference laser tuned to a nonabsorbing frequency near 13170.0/cm. The lidar signal returns were sampled with a 200 range gate (30 vertical resoltion) and averaged over 100 shots
Analysis & experimental evaluation of single point moored buoy systems
Originally issued as Reference No. 69-36, series later renamed WHOI-This report reviews the analysis and the evaluation of surface buoy systems
performed in the Engineering Department of the Woods Hole Oceanographic Institution
in 1968. The buoy systems considered are single point moored, taut
and compound consisting of wire and synthetic ropes, The first part of the
report describes the forcing functions and the system response as measured
in situ during and after launching, The second part presents the results
of the mooring line components testing and evaluation programs performed at
sea or in laboratories. The third part briefly outlines the present development
in telemetry transmission of scientific and engineering information, It
is believed that this systematic engineering effort is an important factor
in the continuous improvement of the reliability and performance of the
deep sea buoy systems used in scientific measurements programs.Submitted to the Office of Naval Research
under Contract N00014-66-C0241, NR 083-00
Design of a stable floating platform for air-sea interaction measurements
The design of an oceanographic platform can be defined as the rational
specification of the platform dimensions and geometry. This specification
is usually the result of an iterative process which compares the platform
performance with the objectives to be reached and the logistic constraints
to be met. This report describes such an exercise.
The scientific objectives - measurements of heat flux at the ocean
surface - are first outlined. The limits of heave and roll motion compatible
with the desired measurement accuracy are then established. Given the
stochastic nature of platform response, these limits are stipulated in terms
of expected means.
A review is then made, in some detail, of the analytical approach
followed and of the computer programs used to compute the statistical
expectations of buoy heave and roll response to random sea excitation.
The next section of the report describes the comprehensive parametric
study performed on some twenty different buoy configurations. The purpose
of this study was first to investigate the dynamic response of a plausible
base line design and of modified versions of the base line. A comparison
of the dynamic response of these configurations could then"be made, and
the good features that this comparison would reveal could be used to design
the buoy prototype. Following this approach a final configuration was
specified which would meet the rather severe motion requirements (0. 2 feet
RMS in heave and 5. 0 degrees RMS in roll in sea state 3).
The final section describes the techniques recommended to deploy and
recover the 60 feet long buoy prototype.Prepared for the Johns Hopkins University, Applied
Physics Laboratory under Subcontract 600651
Radiosonde Temperature Measurements in Strong Inversions: Correction for Thermal Lag Based on an Experiment at the South Pole
Self deployable deep sea moorings
As part of a development effort in the field of moored arrays sponsored by the Office of Naval Technology, the Ocean Structures and
Moorings Laboratory (OSM&L), Applied Ocean Physics and Engineering Department (AOP&E), Woods Hole Oceanographic Institution (WHOI) conducted a study in 1991 to assess the feasibility and the merits of several self-deployable mooring designs. This study included a brief review of the state
of the art, the performance of lab tests to evaluate different mooring line payout concepts, and the preliminary design of a typical candidate mooring.
The results of this study are presented in this report. The report first reviews three types of single point moored arrays
which are amenable to self-deployment: subsurface, subsurface with surface
expression, and surface with bottom inverted catenary. It then describes
the features common to all self-deploying moorings: techniques for line and
instrument storage, means for controlled payout, bottom finders and lock up
mechanisms, and it also outlines desirable specifications for sensor sizes,
cables and connectors.
Next the report reviews typical deployment scenarios from the bottom
up or from the surface down as they apply to the three types of moorings
retained.
In its final section, the report presents the conceptual design of a
6000 meters depth capability, bottom up deployment, candidate mooring.
This configuration should be of strong interest when contemplating the
deployment of a large number of identical subsurface moorings, interconnected
by a bottom cable, and in "close" proximity to one another. The
case study outlines the design objectives and the current profiles,
specifies the main components, evaluates their performance with the help of
a standard computer program, and presents packaging and payout control
details. Finally, a plan is proposed for the controlled, in-situ evaluation
of a prototype.Funding was provided by the Office of Naval Technology under
Contract No. N00014-90-C-0098
Alvin titanium electrical penetrator design, manufacture, and testing : interim report
Under the U.S. Navy's Project TITANES a new titanium alloy
pressure hull has been designed, built, and installed for
use in the deep-submersible ALVIN. The Woods Hole Oceanographic
Institution was assigned the task of designing,
procuring and testing the through-hull electrical penetrators
for the new sphere. This interim report traces
the progress of this Woods Hole program from the initial
design stage, through the various phases of manufacture
and electrical testing, to the installation of the units
in the completed hull, and the numerous laboratory~ pressure
tank, and at-sea tests conducted to verify the satisfactory
performance of the new penetrators. The results of all laboratory
and in-service testing done to date support the conclusion
that the performance of the titanium penetrators
meets all of the original specifications.Office of Naval Research Contract No.
NOr014-73-C-0097
NR 265-10
The Relation of Socioeconomic Status, Parental education, Vocabulary and Language Skills of Children Who Stutter
Purpose: The purpose of this project was to investigate the possible relation between standardized measures of vocabulary/language, mother and father education, and a composite measure of socioeconomic status (SES) for children who do not stutter (CWNS) and children who stutter (CWS). Methods: Participants were 138 CWNS and 159 CWS between the ages of 2;6 and 6;3 and their families. The Hollingshead Four Factor Index of Social Position (i.e., Family SES) was used to calculate SES based on a composite score consisting of weighted values for paternal and maternal education and occupation. Statistical regression analyses were conducted to investigate the relation between parental education and language and vocabulary scores for both the CWNS and CWS. Correlations were calculated between parent education, Family SES, and stuttering severity (e.g., SSI-3 score, % words stuttered). Results: Results indicated that maternal education contributed the greatest amount of variance in vocabulary and language scores for the CWNS and for participants from both groups whose Family SES was in the lowest quartile of the distribution. However, paternal education generally contributed the greatest amount of variance in vocabulary and language scores for the CWS. Higher levels of maternal education were associated with more severe stuttering in the CWS. Conclusion: Results are generally consistent with existing literature on normal language development that indicates maternal education is a robust predictor of the vocabulary and language skills of preschool children. Thus, both father and mothers\u27 education may impact the association between vocabulary/language skills and childhood stuttering, leading investigators who empirically study this association to possibly re-assess their participant selection (e.g., a priori control of parental education) and/or data analyses (e.g., post hoc covariation of parental education). Learning outcomes: The reader will be able to: (a) describe the influence of socioeconomic status on the development of vocabulary and language for children who do and do not stutter; (b) discuss the contribution of maternal education on vocabulary and language development; (c) describe possible reasons why paternal education contributes in unique ways to the vocabulary and language development of children who stutter as well as stuttering severity; and (d) explain possible reasons why socioeconomic status is an important variable for describing language related findings in young children
Speech disfluencies of preschool-age children who do and do not stutter
Purpose—The goals of the present study were to investigate whether (1) the speech disfluencies of preschool-age children are normally distributed; (2) preschool-age children who do (CWS) and do not stutter (CWNS) differ in terms of non-stuttered disfluencies; (3) age, gender, and speechlanguage ability affect the number and type of disfluencies children produce; and (4) parents’ expressed concern that their child stutters is associated with examiners’ judgments of stuttered disfluency.
Method—Four hundred and seventy two children participated, of which 228 were CWS (56 girls), and 244 CWNS (119 girls). Participants provided conversational speech samples that were analyzed for frequency of occurrence of (a) stuttered disfluencies, (b) non-stuttered disfluencies, and (c) total disfluencies.
Results—Results indicated that the underlying distributions of preschool-age children’s stuttered and non-stuttered disfluency counts followed a negative binomial distribution (i.e., were not normal), with more children “piling up” at the low end [none or few disfluencies] and fewer children scoring in the upper [more severe stuttering] end of the distribution. Findings also indicated that non-stuttered disfluencies significantly predicted CWS/CWNS talker group classification, information that may be helpful to augment, but not supplant, talker group classification criteria based on stuttered disfluencies. Moreover, expressed parental concern about stuttering was strongly associated with frequency of stuttered disfluencies
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