128 research outputs found

    Harbor Security System

    Get PDF
    Harbors and ports provide the infrastructure for commercial trade and naval facilities. It is vital to ensure the safety of these locations. The Harbor Security System provides an optical ā€˜gateā€™ using underwater lasers and photodetectors. This system allows monitoring of both surface and submarine vessels traveling into and out of the harbor. Also, the system provides real time alerts when unauthorized vessels enter the harbor. This project provides a proof of concept for a Harbor Security System to be implemented in Portsmouth Harbor. A scaled model of the detection system was constructed and tested. This detection system is capable of detecting surface and submarine vessels along with their velocity and length. Results of the study showed that the average error of the size estimate was 15% and the average error of the velocity estimation ratio(slope) was 9%

    Preparation for an investigation of the thermal radiation characteristics and thermal conductivity of lunar material Final report, 1968

    Get PDF
    Vacuum system and chamber design, and thermal radiation and conductivity measurement techniques for lunar material investigation

    AIRBORNE LIDAR BATHYMETRY BEAM DIAGNOSTICS USING AN UNDERWATER OPTICAL DETECTOR ARRAY

    Get PDF
    The surface geometry of air-water interface is considered as an important factor affecting the performance of Airborne Lidar Bathymetry (ALB), and laser optical communication through the water surface. ALB is a remote sensing technique that utilizes a pulsed green (532 nm) laser mounted to an airborne platform in order to measure water depth. The water surface (i.e., air-water interface) can distort the light beamā€™s ray-path geometry and add uncertainty to range calculation measurements. Previous studies on light refracting through a complex water surface are heavily dependent on theoretical models and simulations. In addition, only very limited work has been conducted to validate these theoretical models using experiments under well-controlled laboratory conditions. The goal of the study is to establish a clear relationship between water-surface conditions and the uncertainty of ALB measurement. This relationship will be determined by conducting more extensive empirical measurements to characterize the changes in beam slant path associated with a variety of short wavelength wind ripples, typically seen in ALB survey conditions. This study will focus on the effects of capillary and gravity-capillary waves with surface wavelengths smaller than the diameter of the laser beam on the water surface. Simulations using Monte-Carlo techniques of the ALB beam footprints and the environmental conditions were used to analyze the ray-path geometries. Based on the simulation results, laboratory experiments were then designed to test key parameters that have the greatest contribution on beam path and direction through the water. The laser beam dispersion experiments were conducted in well-controlled laboratory setting at the University of New Hampshireā€™s Wave and Tow tank. The spatial elevations of the water surface were independently measured using a high resolution wave staff. The refracted laser beam footprint was measured using an underwater optical detector consisting of a 6x6 array of photodiodes. Image processing techniques were used to estimate the laserā€™s incidence angle intercepted by the detector array. Beam patterns that resulted from intersection between the laser beam light field underwater and the detector array were modeled and used to calculate changes in position and orientation for water surface conditions containing wavelengths less than 0.1m. Finally, a total horizontal uncertainty (THU) model was estimated, which can be implemented in total propagated uncertainty (TPU) models for reporting as a measure of the quality of each measurement. The wave refraction error for various sea states and beam characteristics was successfully quantified using both experimental and analytical techniques

    Systematics and diversification patterns of morphologically and ecologically diverse lineages of Agaricomycetes: Clavariaceae and Cantharellales

    Get PDF
    The recent advent of molecular tools and methods to understand the diversity of living organisms allows for exploration of former untestable theories concerning the diversity of fungi. Here we assess the morphologically based classification of the family Clavariaceae in light of molecular phylogenetic reconstruction and propose a revised classification base on natural assemblages. We used stable isotope ratios to uncover a biotrophic nutritional mode for much of the family, which had not been well understood historically. We also investigate several enigmatic lineages of agaricoid or cantharelloid fruiting body producing fungi within a clade of otherwise clavarioid fruiting bodies. We provide the first (partial) support for the Corner hypothesis of morphological evolution. We uncover up to three transitions to agaricoid clades and one transition to a cantharelloid clade. We present a new generic classification for agaricoid clades including the discovery of a new genus and species. Finally we explore the effects of morphology and ecology on diversification rates to explore what traits may be driving patterns of diversity found in the Agaricomycetes. Bayesian Analysis of Macroevolutionary Mixtures (BAMM) and State Speciation and Extinction (BiSSE and MuSSE) analyses were performed on time-calibrated phylogenies of two morphologically and ecologically diverse lineages (the Clavariaceae and the Cantharellales) to test hypotheses that changes in nutritional mode, fruiting body morphology, and hyemnial configuration are associated with shifts in diversification rate. We find that a biotrophic nutritional mode is consistently associated with increased diversification rates while fruiting body morphology and hymenial configuration are only associated with shifts in the Cantharellales

    Determination of Surface Finish Quality of Metals By Means of Optical Methods

    Get PDF
    Ringkasan. Determination of surface - finish quality is done by measurements of its rms. Values of surface roughness and slopes. Mechanical measurements of these properties are done by using a profilometer. This method, however, is limited to surface having asperities larger then the size of the profilometer's tip and is of destructive type of testing. Alternate techniques using optical method based on the theories of Davies and Beckmann are presented. The instrumentation used was a double - beam, modified Perkin-Elmer 621 Spectrophotometer. Results using several randomly roughened metallic surface show good agreement with the existing theory and experimental results.Abstract. Pengukuran kekasaran permukaan-permukaan logam biasanya dilakukan dengan menentukan harga rms. dari Ā seluruh distribusi jarak dari lembah kepuncak beserta orientasi dari setiap faset yang membentuk kekasaran permukannya. Pengukuran kebesaran-kebesaran ini secara mekanis dilakukan dengan mempergunakan profilometer. Akan tetapi, metoda ini terbatas untuk permukaan-permukaan yang ukuran ujung jarum profilometer yang dipakai; lagipula metoda ini termasuk dalam jenis yang disebut "destructive testing". Tulisan ini menguraikan suatu alternatip dengan memakai metoda secara optis dan mempergunakan teori-teori Davies dan Beckmann. Instrumentasi yang dipergunakan ialah suatu Perkin-Elmer 621 Spectrophotometer dengan sistim sinar rangkap dan yang telah dimodifikasikan. Hasil-hasil yang diperoleh dengan mempergunakan berbagai jenis logam yang permukannya telah dikasarkan secara sebarang memberikan kecocokan yang cukup baik bila dibandingkan dengan teori dan hasil-hasil eksperimentil yang ada hingga saat ini

    Polarization, directional distribution, and off-specular peak phenomena in light reflected from roughened surfaces

    Get PDF
    Surface roughness and incident angle effect on angular distribution, polarization, and specular peak of reflected thermal radiatio

    Experimental study of a fiber absorber-suppressor modified Trombe wall

    Get PDF
    An experimental study has been conducted to ascertain the effects of introducing fiber bed absorbers on Trombe wall passive solar collectors. Two identical, Trombe wall passive solar units were constructed that incorporate the basic components of masonry collector-storage walls: glazings, masonry and thermal insulation. Both units were extensively instrumented with thermocouples and heat flux transducers. Ambient temperature, relative humidity, wind speed and insolation are also measured. In the first part of the study the two Trombe wall units were tested with a single glass cover. The thermal performance of both units was found to be virtually identical. In the second part of the study a single cover Trombe wall unit was compared with a double cover unit and the latter was found to have higher air gap and masonry wall temperatures and heat fluxes. In the final phase of the experiment, an absorbing, scattering and emitting fiberglass-like material was placed in the air gap of the single gazed wall. Tests were conducted to compare the solar-thermal performance, heat loss and gain characteristics between the units with and without the fiber absorber-suppressor. This experiment showed that the fiber bed served to decouple the wall at night from its exterior environment and to reduce the heat losses. The modified Trombe wall with the fiber absorber-suppressor out-performed the double glazed Trombe wall system by approximately ten percent gain in useable thermal energy. Also, the fiber bed eliminates one glazing thereby reducing system cost as well

    Elements of Good Training in Anatomic Pathology

    Get PDF
    The American College of Veterinary Pathologistsā€™ (ACVPā€™s) 2007ā€“2012 strategic plan recognized the crisis confronting academic training programs and formed a task force to address these concerns. One area of concern identified by the ACVP Training Program Development Task Force was the lack of guidelines to make training more consistent across all programs and provide justification for maintaining or increasing faculty numbers and training resources. Training guidelines for clinical pathology have been outlined in three publications.1,2,4 The current document addresses the need for training guidelines in veterinary anatomic pathology
    • ā€¦
    corecore