Underwater acoustics at the Johns Hopkins University Applied Physics Lab

2015 ◽  
Vol 137 (4) ◽  
pp. 2332-2332
Author(s):  
Bruce K. Newhall ◽  
James W. Jenkins
Keyword(s):  
Underwater Acoustics ◽  
Applied Physics ◽  
Johns Hopkins University

Additive Manufacturing of Pressure Vessels (With Plating)

2017 ◽  
Author(s):  
Brendan P. McNelly ◽  
Richard L. Hooks ◽  
William R. Setzler ◽  
Craig S. Hughes
Keyword(s):  
Additive Manufacturing ◽  
High Stress ◽  
High Strength ◽  
Pressure Vessels ◽  
Applied Physics ◽  
Metal Plating ◽  
Johns Hopkins University ◽  
Significant Strength ◽  
Uniform Wall ◽  
Manufacturing Techniques

Additive manufacturing (AM) allows for product development with light weight, fewer machining constraints, and reduced costs depending on the application. While AM is an emerging field, there is limited research on the use of AM for pressure vessels or implementation in high stress environments. Depending on the design approach and limitations of traditional material-removal fabrication techniques, AM parts can achieve high strength-to-weight ratios with reduced manufacturing efforts. Coupling AM with alternative metal and composite materials allows for unique designs that have high strength-to-weight ratios for pressure-based applications. The Johns Hopkins University Applied Physics Laboratory (JHU/APL) has conducted research on a number of these composite designs, focusing on the use of carbon fiber or metal plating with the AM materials. Before implementing AM in field tested prototypes, JHU/APL performed strength limitation tests on AM pressure vessels (PVs) in the laboratory to prove their effectiveness. PVs constructed with varying thicknesses and coating techniques were divided into three groups, each with a uniform wall thickness that provided a congruent surface area to withstand higher pressures. These PVs were then paired with one of three coating/plating technologies, forming a trade matrix of varying AM thicknesses and plating techniques. Once fabricated and plated, these test PVs were hydro-statically tested at increasing pressure levels. This pressure testing demonstrates that the use of AM to create PVs, when paired with specific plating techniques, can result in structures with significant strength capabilities at lighter than normal PV weights. Furthermore, JHU/APL has begun to test the AM PVs in a number of research projects. Such testing is desired because these unique parts can be easily manufactured in shapes and volumes that were previously unattainable through common manufacturing techniques. AM parts are now commonly used in air-frames; however, in higher pressure underwater scenarios AM’s capabilities are unproven. JHU/APL has begun to apply this new and emergent field to the effective design of AM PVs, which can play a significant role in the field of underwater vehicles and similar projects.

scholarly journals Six decades of evolution in underwater acoustics at the Applied Physics Laboratory - University of Washington (APL-UW)

2015 ◽  
Author(s):  
Kevin Williams ◽  
Terry Ewart ◽  
Darrell Jackson ◽  
Eric Thorsos ◽  
Peter Dahl ◽  
...  
Keyword(s):  
Underwater Acoustics ◽  
Applied Physics ◽  
University Of Washington ◽  
Physics Laboratory

Up Close: Johns Hopkins Center for Nondestructive Evaluation

MRS Bulletin ◽  
1988 ◽  
Vol 13 (1) ◽  
pp. 27-33
Author(s):  
L.S. Millberg
Keyword(s):  
Process Control ◽  
Nondestructive Evaluation ◽  
Intelligent Manufacturing ◽  
Advanced Materials ◽  
Applied Physics ◽  
Cooperative Research ◽  
University Center ◽  
Johns Hopkins University ◽  
And Performance ◽  
Talented Students

Nondestructive evaluation has historically been used almost exclusively for detecting macroscopic defects after materials have been made or put into service. However, the role of NDE is now changing to include in-process control in an effort to increase yields and performance of materials. This includes materials stability during transport, storage, and fabrication, as well as degradation behavior during in-service life. The NDE community has implied that applying NDE in these ways is crucial to solving the economic problems of U.S. manufacturing industries. So called “intelligent manufacturing” is impossible without integrating modern NDE techniques into the production of today's advanced materials.The Johns Hopkins University Center for Nondestructive Evaluation (CNDE) was established in 1984 as an interdisciplinary center for research and instruction, drawing on the resources and talent of the School of Engineering, Applied Physics Laboratory, School of Medicine, and School of Arts and Sciences. Currently 31 faculty or senior staff work with the Center. The techniques being developed are aimed at reliable in-process control of materials and processes. Another important purpose is the education of talented students who will enter the NDE field; 150 students are associated with the Center, a third of whom are graduate students. The CNDE also provides both research collaborators and industrial sponsors with access to all NDE research and instruction at Johns Hopkins University. Twenty-six research institutions have formal cooperative research programs and 19 organizations are corporate sponsors (see Figure 1).

Antarctic airborne radio echo sounding, 1977–78

Polar Record ◽  
1978 ◽  
Vol 19 (120) ◽  
pp. 267-273 ◽  
Author(s):  
D. J. Drewry ◽  
D. T. Meldrum
Keyword(s):  
National Science Foundation ◽  
Austral Summer ◽  
Applied Physics ◽  
Joint Project ◽  
Johns Hopkins University ◽  
The Us ◽  
National Science ◽  
Radio Echo Sounding ◽  
Polar Research Institute ◽  
Echo Sounding

During the austral summer 1977–78 the Scott Polar Research Institute (SPRI) conducted a fifth season of airborne radio echo sounding in Antarctica as part of a joint project with the US National Science Foundation Division of Polar Programs (NSF-DPP) and the Technical University of Denmark (TUD). In addition, trials were undertaken of a magnetometer installation, developed and operated, under NSF contract, by the Applied Physics Laboratory (APL) of the Johns Hopkins University, USA.

A discussion on orbital analysis - Data and orbit analysis in support of the U.S.. Navy satellite Doppler system

1967 ◽  
Vol 262 (1124) ◽  
pp. 89-99 ◽  
Keyword(s):  
Analysis Data ◽  
Applied Physics ◽  
Paper Briefly ◽  
Doppler System ◽  
Johns Hopkins University ◽  
Doppler Data ◽  
Orbit Analysis ◽  
Major Application ◽  
Orbital Analysis ◽  
The U.S

This paper briefly describes the data and orbit analysis activities at The Johns Hopkins University Applied Physics Laboratory which support the U.S. Navy satellite Doppler system Tranet. Two topics are discussed in detail which are directly related to geodetic research, the major application of this system. These topics are the editing and archiving of the Doppler data and the generating of orbital ephemerides to an accuracy compatible with the 10 m accuracy of the experimental Doppler data.

scholarly journals Transport and characterization of ambient biological aerosol near Laurel, MD

2010 ◽  
Vol 7 (5) ◽  
pp. 6725-6747 ◽  
Author(s):  
J. L. Santarpia ◽  
D. Cunningham ◽  
J. Gilberry ◽  
S. Kim ◽  
E. E. Smith ◽  
...  
Keyword(s):  
16S Rrna ◽  
Back Trajectory ◽  
Culturable Bacteria ◽  
Applied Physics ◽  
Biochemical Tests ◽  
Back Trajectories ◽  
Johns Hopkins University ◽  
Bacterial Aerosol ◽  
Bacteria And Fungi ◽  
16S Rrna Diversity

Abstract. Bacterial aerosol have been observed and studied in the ambient environment since the mid nineteenth century. These studies have sought to provide a better understanding of the diversity, variability and factors that control the biological aerosol population. In this study, we show comparisons between diversity of culturable bacteria and fungi, using culture and clinical biochemical tests, and 16S rRNA diversity using Affymetrix PhyloChips. Comparing the culturable fraction and surveying the total 16S rRNA of each sample provides a comprehensive look at the bacterial population studied and allows comparison with previous studies. Thirty-six hour back-trajectories of the air parcels sampled, over the two day period beginning 4 November 2008, provide information on the sources of aerosol sampled on the campus of Johns Hopkins University Applied Physics Laboratory in Laurel, MD. This study indicates that back-trajectory modeling of air parcels may provide insights into the observed diversity of biological aerosol.

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