Engineering Commons^™

Scanning Electron Microscopy Study Of Biofilms On Silicone Voice Prosthesis, T. R. Neu, F. Dijk, G. J. Verkerke, H. C. Van Der Mei, H. J. Busscher

Cells and Materials

Patients after laryngectomy often receive silicone made voice prostheses fot speech rehabilitation. The prosthesis is inserted in a shunt between the trachea and the digestive tract. As the prosthesis is placed in a nonsterile environment it becomes rapidly colonized by microorganisms eventually leading to failure and frequent exchange of the implant. In this study, explanted "Groningen Button" silicone voice prostheses were used to investigate by scanning electron microscopy the biofilm developing on the implant. Two main types of microbial colonization forms could be distinguished. Firstly, macroscopically visible, single colonies dominating on the esophagus side of the prosthesis were found, which …

Apatite - Cholesterol Agglomerates In Human Atherosclerotic Lesions, Sara Sarig, Danielle Hirsch, Reuven Azoury, Teddy A. Weiss, Iony Katz, Howard S. Kruth

Cells and Materials

The purpose of this study was to examine the ultrastructural relationships of cholesterol crystals and apatite deposits in human atherosclerotic lesions. Segments of human aortic atherosclerotic lesions were obtained at autopsy , fixed in glutaraldehyde and dehydrated without using any organic solvents. The aortic segments were coated with carbon and subjected to various scanning electron microscope analyses. These included secondary electron imaging, back scattering of primary electrons, energy dispersive X-ray analysis of selected spots followed by area mapping of calcium and phosphorus , and cathodoluminescence.

The information gathered from scanning of selected areas in the lesions by all the techniques …

Hydrodynamics For Water Quality Models, Mark Dortch, Billy Johnson

United States Army: Publications

During the past decade, the US Army Engineer Waterways Experiment station (WES) has developed and applied a variety of numerical water quality models for surface waters. In most cases, the transport terms of these models have been computed using output from numerical hydrodynamic models. This paper summarizes the experience of linking water quality models to hydrodynamic models and examines the need for such linkages.

Physical Modeling Of A High Velocity Covered Urban Drainage Channel, Stephen E. Stump, Charles H. Tate, Robert U. Castle

United States Army: Publications

The design of Oak Street Drain, a 3-mile-long rectangular open channel project in Corona, CA, requires a covered section with a sinuous alignment to avoid commercial development. The alignment includes a reverse 100-ft-radius curve and a long 200-ft-radius curve to convey the 100-year design flow of 7,100 cfs at velocities of 40 fps. A physical model was constructed to verify that the proposed design would pass the design flow without adverse hydraulic conditions.

Hydrodynamic Forces And Evolution Of A Nearshore Berm At South Padre Island, Texas, James A. Aidala, Cheryl E. Burke, T. Neil Mclellan

United States Army: Publications

The evolution of a nearshore feeder berm was correlated to the hydrodynamic forces acting on it for periods of time during which bathymetric and hydrodynamic data sets were available. The evolution of the berm was described in the context of movement and erosion based on wave orbital velocity and bottom current. The berm was constructed and placed offshore at South Padre Island, Texas.

Visualization Of Groundwater Contaminant Parameters, Gregory D. Comes, James Warner, Paul Miller

United States Army: Publications

Numerical groundwater contaminant modeling is a powerful tool to study the extent of subsurface contamination. Three-dimensional contaminant transport models can predict the future lateral and vertical extent of contamination. Geotechnical and hydrological data is required for the calibration and operation of such models. Understanding the interrelationships of the enormous volumes of data required becomes an onerous task. Visualization of both the input and output data aids the researcher in calibration and comprehension of numerical model results. This paper describes the integration of three-dimensional computer visualization with geotechnical and hydrological parameters for numerical groundwater contaminant modeling. Visualization of subsurface parameters in …

The Application Of Ultrasonic Surface Detectors To Hopper Dredge Production Monitoring, Stephen H. Scott, Angela Freeman

United States Army: Publications

Ultrasonic surface detectors were installed on the us Army Corps of Engineers hopper dredge WHEELER for measuring dredge production. Ultrasonic sensors were installed over the bow and stern of the vessel, port and starboard, to measure vessel draft as a function of dredged material load in the hopper. Four ultrasonic sensors were installed over the hopper to measure the bin water depth in the hopper. This paper describes the ultrasonic sensor operation and installation, and data acquisition and analysis for the test series.

Brief History Of Afmic (Total Manpower), Robert Bolin , Depositor, Jonathan Clemente

United States Department of Defense Military Intelligence

Brief History of AFMIC (Total Manpower) from WWI/ (33) to 1992 (82)

U.S. Army Medical Intelligence Office Under SG

DLA Assumes GMI Medical Intelligence Mission

Army SG Continues to Perfonn Medical S&TI

DLA has RIF: Medical Intelligence Division Abolished

Army SG Assumes Entire Medical Intelligence Mission

USAMIIA Fonned (Located at ForrestaJ Buildng)

USAMIIA Move to Fort Detrick (Building 862)

Congress Eliminates All Funding for USAMIlA

DIAlGDIP Program Manager Appeals

Congress Allows Re-establishment of USAMIlA

- Must be Tri-Service

- Must be an Intelligence Activity

Tri-Service AFMIC Established

Anny (DCSINT and SG) Executive Agent

New Building on Fort Detrick

First Non-Army …

Bulletin - Winter, 1992, Civil Aviation Medical Association

Browse all Civil Aviation Medical Association Newsletters

A twelve page newsletter of the Civil Aviation Medical Association. The newsletter provided news about civil aviation medicine and information related to the organization.

Biological Discussion Missouri National Recreational River Rehabilitation Gavins Point Dam To Ponca State Park, Nebraska & South Dakota

United States Army Corps of Engineers, Omaha District

The corps of Engineers has received funding for the rehabilitation of the section 32 erosion control projects along the Missouri National Recreational River (MNRR). The project rehabilitation work is as outlined on the attached construction schedule.

Since the Fish & WIldlife's biological opinion on the section 32 program dated March 10, 1980, additional species that may occur in the program area have been listed, including the interior least tern, piping plover, the American burying beetle, and the pallid sturgeon.

The American burying beetle is listed as a federally endangered species in South Dakota. Extant populations are known to occur only …

Doctor Of Science In Computer Information Systems, Nova Southeastern University

College of Engineering and Computing Course Catalogs

No abstract provided.

Unequal Error Protection Qpsk Modulation Codes, Robert H. Morelos-Zaragoza, Shu Lin

Faculty Publications

The authors use binary linear UEP (LUEP) codes, in combination with a QPSK signal set and Gray mapping, to obtain new efficient block QPSK modulation codes with unequal minimum squared Euclidean distances. They give several examples of codes that have the same minimum squared Euclidean distance as the best QPSK modulation codes of the same rate and length. A new suboptimal two-stage soft-decision decoding is applied to LUEP QPSK modulation codes.

Photonics In Switching, Harvard S. Hinton

Electrical and Computer Engineering Faculty Publications

One of the keys to the future of telecommunications companies will be their ability to provide new broadband services to both the business community and residential customers. With the new services will come the need for the equivalent of a broadband switching office. Such a system could require the capability of supporting in excess of 10000 users with broadband channel bit rates exceeding 100 Mb/s. This implies a switching fabric the aggregate bit rate of which could be greater than 1 Tb/s. Guided-wave technology and free-space technology switching fabrics are discussed. Three time-division-based switching fabrics are proposed, and two wavelength-division-based …

Switching To Photonics, Harvard S. Hinton

Electrical and Computer Engineering Faculty Publications

The use of hardware that exploits the interplay of photons and electrons to switch voice, data, and video is discussed. The two directions being taken by current research-guided-wave and free-space photonics-are examined. Photonic time-slot interchanges are described. Multidivisional fabrics, based on a combination of space-division and time-division multiplexing, are considered, as is the wavelength-division-based photonic packet switch, another kind of multidimensional fabric. The use of self-electrooptic effect devices, (SEEDs) is discussed.

All-Optical Synchronisation And Multiplication Of The Frequency Of Mode-Locked Signals, P. Phelan, Gerald Farrell, Joe Hegarty

Articles

We report all-optical synchronized multiplication by rational fractions of the modulation frequency of optical signals in self-pulsing two-section semiconductor laser diodes. The effect is based on the overlap of harmonics of the input signal with harmonics of the self-pulsation. We illustrate this new generic function with modelocked inputs rich in harmonics were fractions of 1,2, and 3 / 2 are generated, and we identify a number of applications for this effect.

Investigation On The Collagen Fiber Network In Human Dental Tissues - Transmission And Scanning Electron Microscopy, C. Marchetti, P. Menghini, C. Piacentini

Cells and Materials

The collagen fiber component of pulp, dentine and cementum, has been studied by isolating it from the inorganic component and the organic non-collagen matrix. This study was carried out on healthy molar and premolar adult teeth. Following demineralization all of the non-collagenous components of the tooth were removed by sequential treatment with H202, with different concentrations of trypsin and with EDTA. The transmission (TEM) and scanning (SEM) electron microscopy investigation confirmed that such a technique is an accurate method for isolating the collagen fibers while preserving their position and their ultrastructure in the dental tissue. The use of TEM and …

Scanning Electron Microscope Observation Of Lubricious Polymer Surface For Medical Use, Hiroyuki Inoue, Yoshikimi Uyama, Emiko Uchida, Yoshito Ikada

Cells and Materials

A peculiar textured structure was found by scanning electron microscopic (SEM) observation on polymer films surface-grafted with water-soluble polyacrylamide and poly(N,N-dimethylacrylamide) after exposure to ozone. The grafted surface became very hydrophilic and highly lubricated when brought into contact with water, due to hydration of the grafted surface layer. Unless water was present, the surface did not become slippery at all. SEM of the grafted surface revealed different profiles, depending on the graft density as well as the process of drying prior to the SEM observation. There was no significant difference between the virgin and the surface-grafted film, when air-dried under …

Interaction Of Liposomal Drug Delivery Systems With Cells And Tissues: Microscopic Studies, M. Foldvari, G. T. Faulkner, C. Mezei, M. Mezei

Cells and Materials

Liposomes , as drug carriers, can be administered into the body by several routes e.g. intravenously, intraperitoneally, intramuscularly, intratracheally and topically among others. Radiolabelled markers are suitable to monitor the distribution and elimination of liposomes, but the tissue deposition of intact liposomes, the mode and sites of drug release from the liposomes and liposome-cell interactions cannot be investigated morphologically. Microscopic techniques could provide information regarding the intact state of liposomes and possibly the dynamics of liposomes in tissues provided that they can be identified with certainty in vivo. This is a formidable problem and in spite of several attempts, there …

Three-Dimensional Incompressible Flow Calculations With Maccormack's Method, Robert S. Bernard, Michael L. Schneider

United States Army: Publications

MAC3D is a finite-volume computer code that uses MacCormack's method to calculate three-dimensional incompressible flow on staggered Marker-and-Cell grids. The code accepts nonuniform, nonorthogonal grids for any curvilinear domain that can be mapped onto a single rectangular block. It is applicable for free-surface flow at low Froude number, and for confined flow in general. Computed results from MAC3D are presented for laminar flow in channels with internal obstacles and curved boundaries.

Improved Thermal Predictions In Ce-Qual-W2, Raymond S. Chapman, Thomas M. Cole

United States Army: Publications

Recent modifications to the transport scheme within the two-dimensional hydrodynamic and water quality model CEQUAL- W2 have resulted in a significant improvement in the prediction of temperature distributions by reducing numerical diffusion. These changes allow for a more accurate description of wind effects in the model. This paper briefly describes the modifications to CE-QUAL-W2 and presents results of two simulations both with and without the improvements to the transport algorithm.

Release Alternatives On A 3-D Salinity Simulation, Bernard B. Hsieh

United States Army: Publications

Hydraulic structures such as darns, locks or diversion gates, in the upstream or tributary of an estuary system can control necessary freshwater discharge to meet downstream water quality standards. One of the most significant purposes of these structures is maintaining target salinity to satisfy the environment concerns, such as fishery spawning in the high-flow season and drinking water criteria in the low-flow period. In order to evaluate possible alternative regulations for the reservoir operation, a reliable three-dimensional (3-D) hydrodynamic model is required as a management tool to simulate the impact of salinity variations due to release policy changes. This paper …

Gas Transfer In Diffused Bubble Plumes, Steven C. Wilhelms, Sandra K. Martin

United States Army: Publications

The gas transfer in aeration systems is broken into two processes: gas transfer at the bubble interface and gas transfer at the water surface. Experiments were conducted to separate these two sources of dissolved gas. Oxygen absorption was measured in a laboratory tank with air being diffused through a porous diffuser and then with nitrogen gas being diffused. The combination of these experiments along with reformulation of the theoretical transfer equation permit separation of the gas transfer at the water surface and in the rising bubble plume. Estimates of the exchange coefficient for the plume and surface are given.

Hydraulic Structures Versus Zebra Mussels, John J. Ingram, Andrew C. Miller

United States Army: Publications

The United States Army Corps of Engineers (USAE) has begun a four-year research program to develop environmentally sound control strategies for zebra mussel (Dreissena polymorpha) infestations at public facilities. The USAE Waterways Experiment Station has initiated research for these facilities which include water-intake structures, navigation locks, gated dams, outlet works, pumping plants, hydropower plants, drainage structures, dredges and commercial vessels.

Computation Of Long-Term Three-Dimensional Hydrodynamics Of New York Bight, Keu W. Kim, David J. Mark, Norman W. Scheffner, Lynn M. Bocamazo

United States Army: Publications

A time-varying three-dimensional (3D) numerical hydrodynamic model has been applied to the New York Bight to provide flow fields to a 3D water quality model. The spatial computational domain extends from Cape May, New Jersey at its south-west end and Narragansett Bay, Rhode Island, at the north-east end and seaward to the shelf-break. As illustrated below, the numerical model has more than 2500 active horizontal cells and ten vertical layers. Features of the hydrodynamic model include coupling of temperature grids to better represent geometric features, and an algebraic vertical turbulence model based upon the assumption that turbulence production and dissipation …

Stable Channel And Environmental Design Considerations For An Urban Flood Control Project, Edward F. Sing, Daniel Pridal, Thea Lane

United States Army: Publications

A case study will be presented of a two phase process of development of the hydraulic design of a flood control project incorporating a creek nestled within an urban greenbelt. The green belt reach consists of the existing, 5 to 15 foot wide tree-lined, low flow channel set within an approximate 100 to 150 foot wide floodway to be created by low berms. Any project features proposed for this reach would need to be environmentally and aesthetically acceptable. The design approach taken in developing the flood control and channel stabilization plan for the greenbelt reach will be presented. This approach …

Rapid Detection Of Hydrocarbon Contamination In Ground Water And Soil, A. M. Chrestman, G. D. Comes, S. S. Kooper, P. G. Malone

United States Army: Publications

In situ fluorometry is being developed as a method for rapidly detecting and quantifying hydrocarbon contamination in ground water and soil. The results of a fluorometry survey over a site having known fuel contamination are compared to results from a soil gas survey over the same site. The fluorometry data showed three additional contaminated areas that were not detected by soil gas measurements. Soil analyses confirmed the presence of the contaminated areas.

Using A Numerical Model To Evaluate Dredging Options, Ronald R. Copeland

United States Army: Publications

A study was conducted to address a shoaling problem in the vicinity of the Cubits Gap distributary on the lower Mississippi River. Upstream from Cubits Gap the river is relatively deep, but the channel depth decreases as it approaches the distributary, where frequent dredging is required. A one-dimensional numerical model was used to evaluate alternative dredging operations and to forecast sediment accumulation. The numerical model was also used to forecast sediment accumulation based on 30-day flow projections. This information can be used to help determine when to initiate dredging fleet mobilization.

Environmental Engineering Options For Managing Contaminated Sediment, Norman R. Francingues. Jr.

United States Army: Publications

Technologies that have been identified as feasible for remediating contaminated sediment and are peing considered for demonstration in the Great Lakes are presented in this paper. This review is limited to the components and technologies required for removal and management of highly contaminated sediment. Over two hundred technology process options were reviewed for effectiveness, implementability and costs. However, few of these processes have actually been applied to contaminated sediment on a full scale. Most of the technology evaluations have been conducted at the bench scale with limited data available for pilot scale assessment. Therefore, further testing and evaluation of the …

In-Channel Sediment Basins: An Alternative To Dam-Style Debris Basins, Wendy S. Gist, Scott E. Stonestreet, Ronald R. Copeland

United States Army: Publications

In-channel sediment basins were designed, in lieu of a traditional debris basin, to capture large sediment loads at the upstream end of a proposed flood control channel. A numerical model, HEC-6, was used to size the basins.

Numerical Modeling Of Reservoir Tailrace Hydraulics For Water Quality And Habitat Analysis, Brad R. Hall, John Nestler

United States Army: Publications

The Waterways Experiment Station has developed dynamic numerical hydraulic and water quality simulation models of the Missouri River reaches downstream of Fort Peck, Garrison, and Fort Randall Dams in support of Master Water Control Manual studies. The numerical modeling approach is to compute spatial and temporal variations in stage and discharge in each of these reaches using UNET, a one-dimensional dynamic flow model. Hydraulic and geometric parameters calculated by UNET are then linked with transport algorithms in the CE-QUAL-RIV1 numerical model for computing spatial and temporal variation in water temperature and dissolved oxygen in each of the modeled reaches. Parameters …