Naval Sea Systems Command

In the present study, the overall economic impact of hull fouling on a mid-sized naval surface ship (Arleigh Burke-class destroyer DDG-51) has been analyzed. A range of costs associated with hull fouling was examined, including expenditures for fuel, hull coatings, hull coating application and removal, and hull cleaning. The results indicate that the primary cost associated with fouling is due to increased fuel consumption attributable to increased frictional drag. The costs related to hull cleaning and painting are much lower than the fuel costs. The overall cost associated with hull fouling for the Navy's present coating, cleaning, and fouling level is estimated to be $56M per year for the entire DDG-51 class or $1B over 15 years. The results of this study provide guidance as to the amount of money that can be reasonably spent for research, development, acquisition, and implementation of new technologies or management strategies to combat hull fouling.

Far‐field scattering of randomly deposited Au nanoparticles (NPs) is demonstrated as a physically unclonable optical function for anti‐counterfeit applications in which the scattering patterns are easily produced yet impractical to replicate. Colloidal metal NPs are superb components for nanoscale labels owing to their small dimensions and intense far‐field scattering visible at wavelengths that depend on colloidal size, shape, composition, and their local environment. The feasibility of Au NP depositions as nanofingerprints is presented using a simple pattern matching algorithm. These NPs offer extended functionality as environmental sensors. Taking advantage of the local refractive index dependent scattering wavelengths of metal NPs, a detectable color change is also demonstrated from a nanofingerprint comprised of Au and Ag NPs when placed in media with different refractive index. The facile deposition method coupled with the intense scattering and optical response of metal NPs provides physically unclonable tags (nanofingerprints) with the ability to serve as tamper‐evident and aging labels.

Power electronics based power distribution systems (PEDSs) are becoming increasingly common, particularly in marine and aerospace applications. Stability analysis of this class of systems is crucial due to the potential for negative impedance instability. Existing techniques of stability analysis introduce artificial conservativeness, are sensitive to component grouping, and at the same time do not explicitly address uncertainties and variations in operating point. A new stability criterion, which reduces artificial conservativeness and is also insensitive to component grouping is described. In addition, a means of readily establishing design specifications from an arbitrary stability criterion which specifically includes a provision to incorporate uncertainty, parameter variation, and nonlinearities is set forth. The method is presented in the context of a hardware test system and is experimentally validated.

The global economic, security, and health challenges presented by counterfeit goods require new approaches toward anti-counterfeit labels.

Summary form only given. The face recognition vendor test (FRVT) 2002 is an independently administered technology evaluation of mature face recognition systems. FRVT 2002 provides performance measures for assessing the capability of face recognition systems to meet requirements for large-scale, real-world applications. Participation in FRVT 2002 was open to commercial and mature prototype systems from universities, research institutes, and companies. Ten companies submitted either commercial or prototype systems. FRVT 2002 computed performance statistics on an extremely large data set-121,589 operational facial images of 37,437 individuals. FRVT 2002 1) characterized identification and watch list performance as a function of database size, 2) estimated the variability in performance for different groups of people, 3) characterized performance as a function of elapsed time between enrolled and new images of a person, and 4) investigated the effect of demographics on performance. FRVT 2002 showed that recognition from indoor images has made substantial progress since FRVT 2000. Demographic results show that males are easier to recognize than females and that older people are easier to recognize than younger people. FRVT 2002 also assessed the impact of three new techniques for improving face recognition: three-dimensional morphable models, normalization of similarity scores, and face recognition from video sequences. Results show that three-dimensional morphable models and normalization increase performance and that face recognition from video sequences offers only a limited increase in performance over still images. A new XML-based evaluation protocol was developed for FRVT 2002. This protocol is flexible and supports evaluations of biometrics in general The FRVT 2002 reports can be found at http://www.frvt.org.

This paper introduces two kinds of control schemes: vector control and direct torque control (DTC). These control schemes can be extensively applied to the operation of a five-phase induction motor using a fully digital implementation. Vector control of the five-phase induction motor not only achieves high drive performance, but also generates the desired nearly rectangular current waveforms and flux profile in the air-gap resulting in an improvement in air gap flux density and an increase of 10% in output torque. The DTC method has additional advantages when applied to multiphase, in this case a five-phase, induction motor. The five-phase inverter provides 32 space voltage vectors in comparison to 8 space voltage vectors provided by the three-phase inverter. Therefore, a more elaborate flux and torque control algorithm for the five-phase induction motor can be employed. Direct torque control of the five-phase induction motor reduces the amplitude of the ripples of both the stator flux and the torque, resulting in a more precise flux and torque control. A 32-b floating-point TMS320C32 digital signal processor (DSP) enables these two sophisticated control techniques to be conveniently implemented with high control precision. Experimental results show that an ideal control capability is obtained for both control methods when applied to the five-phase induction motor and further validates theoretical analysis.

We sought to prospectively assess the diagnostic performance of a high-resolution positron emission tomography (PET) scanner using mild breast compression (positron emission mammography [PEM]). Data were collected on concomitant medical conditions to assess potential confounding factors. At four centers, 94 consecutive women with known breast cancer or suspicious breast lesions received 18F-fluorodeoxyglucose (FDG) intravenously, followed by PEM scans. Readers were provided clinical histories and x-ray mammograms (when available). After excluding inevaluable cases and two cases of lymphoma, PEM readings were correlated with histopathology for 92 lesions in 77 women: 77 index lesions (42 malignant), 3 ipsilateral lesions (3 malignant), and 12 contralateral lesions (3 malignant). Of 48 cancers, 16 (33%) were clinically evident; 11 (23%) were ductal carcinoma in situ (DCIS), and 37 (77%) were invasive (30 ductal, 4 lobular, and 3 mixed; median size 21 mm). PEM depicted 10 of 11 (91%) DCIS and 33 of 37 (89%) invasive cancers. PEM was positive in 1 of 2 T1a tumors, 4 of 6 T1b tumors, 7 of 7 T1c tumors, and 4 of 4 cases where tumor size was not available (e.g., no surgical follow-up). PEM sensitivity for detecting cancer was 90%, specificity 86%, positive predictive value (PPV) 88%, negative predictive value (NPV) 88%, accuracy 88%, and area under the receiver-operating characteristic curve (Az) 0.918. In three patients, cancer foci were identified only on PEM, significantly changing patient management. Excluding eight diabetic subjects and eight subjects whose lesions were characterized as clearly benign with conventional imaging, PEM sensitivity was 91%, specificity 93%, PPV 95%, NPV 88%, accuracy 92%, and Az 0.949 when interpreted with mammographic and clinical findings. FDG PEM has high diagnostic accuracy for breast lesions, including DCIS.

The optical properties of metal nanomaterials are determined by a set of parameters that include composition, particle size and shape, overall architecture, and local environment. This Tutorial Review examines the influence of each of these factors on the localized surface plasmon resonance of colloidal metal nanoparticles. This examination is paralleled with a discussion of the advances which have enabled the synthesis of structurally defined metal nanomaterials, as these samples serve as the best platforms for elucidating the fundamental properties of plasmonic colloids. Based on the analysis of such samples, five guidelines are presented to aid the rational design and synthesis of new metal nanostructures for advanced applications in nanomedicine, energy, chemical sensing, and colloidal plasmonics in general.

Recent developments in superconducting magnetic gradiometer technology have led to the construction of advanced ultrasensitive gradiometer/magnetometer arrays. Details of construction techniques and data showing operational capabilities are presented. The most recent of the gradiometer/magnetometer arrays simultaneously measures five independent spatial gradients of the magnetic field and three vector components of the magnetic field. The measured signals from this array are subjected to a novel signal processing technique which provides detailed information about the magnetic signal source.

This study investigated two variables associated with scaling and planning (S&RP): operator experience level and root surface access. One hundred and fourteen periodontally involved, single-rooted teeth designated for extraction were randomly distributed among four operators of various experience levels for either an open or closed session of S&RP. Immediately after treatment, the teeth were extracted, washed, and scored for residual calculus in a blind manner. Results showed that there was no difference in S&RP effectiveness for experience level or type of procedure in shallow (1-3 mm) pockets. However, in moderate (4-6 mm) and deep (greater than 6 mm) periodontal pockets, S&RP combined with an open flap procedure was more effective than S&RP alone for both experience levels. Also, the more experienced operators produced a significantly greater number of calculus-free root surfaces than the less experienced operators in periodontal pockets with moderate and deep probing depths. Clinical application of these results suggests that surgical access is associated with thorough surface debridement in periodontal pockets with moderate-to-advanced probing depths. However, more experienced operators could be expected to render more effective soft surface debridement.

A new concept of polarization reversal and domain dynamics in modified ferroelectrics is presented. Accordingly, clusters with a reversed polarization within ferroelectric domains are nucleated under applied field in the vicinity of random fields around quenched defects. The random fields significantly lower the activation barrier required for nucleation, thus controlling the kinetics of polarization reversal and domain dynamics. In this model, polarization switching occurs by the breakdown of ferroelectric long-range order, through a polar cluster state.

Abstract On February 4, 2008, Admiral Paul Sullivan, Commander of the Naval Sea Systems Command, sent out a letter entitled: Ship Design and Analysis Tool Goals. The purpose of the widely distributed memorandum was to state the requirements and high‐level capability goals for NAVSEA design synthesis and analysis tools. In this memo, Admiral Sullivan expressed the need for evolving models and analysis tools to be compatible with, among other things, set‐based design (SBD). Admiral Sullivan's memo was a major step toward improving ship design programs with new, more powerful analytical support tools but many have asked, “What is Set‐Based Design and how does it relate to Naval Ship Design?” SBD is a complex design method that requires a shift in how one thinks about and manages design. The SBD paradigm can replace point‐based design construction with design discovery; it allows more of the design effort to proceed concurrently and defers detailed specifications until trade‐offs are more fully understood. This paper describes the principles of SBD citing improvements SBD in design practice that have set the stage for SBD, and relating these principles to current Navy ship design issues.

A potential emerging problem associated with increasingly popularized extreme conditioning programs (ECPs) has been identified by the military and civilian communities. That is, there is an apparent disproportionate musculoskeletal injury risk from these demanding programs, particularly for novice participants, resulting in lost duty time, medical treatment, and extensive rehabilitation. This is a significant and costly concern for the military with regard to effectively maintaining operational readiness of the Force. While there are certain recognized positive aspects of ECPs that address a perceived and/or actual unfulfilled conditioning need for many individuals and military units, these programs have limitations and should be considered carefully. Moreover, certain distinctive characteristics of ECPs appear to violate recognized accepted standards for safely and appropriately developing muscular fitness and are not uniformly aligned with established and accepted training doctrine. Accordingly, practical solutions to improve ECP prescription and implementation and reduce injury risk are of paramount importance.

Studies over the past 25 years have shown that heavy ions can trigger catastrophic failure modes in power MOSFETs [e.g., single-event gate rupture (SEGR) and single-event burnout (SEB)]. In 1996, two papers were published in a special issue of the IEEE Transaction on Nuclear Science [Johnson, Palau, Dachs, Galloway and Schrimpf, “A Review of the Techniques Used for Modeling Single-Event Effects in Power MOSFETs,” IEEE Trans. Nucl. Sci., vol. 43, no. 2, pp. 546–560, April. 1996], [Titus and Wheatley, “Experimental Studies of Single-Event Gate Rupture and Burnout in Vertical Power MOSFETs,” IEEE Trans. Nucl. Sci., vol. 43, no. 2, pp. 533–545, Apr. 1996]. Those two papers continue to provide excellent information and references with regard to SEB and SEGR in vertical planar MOSFETs. This paper provides updated references/information and provides an updated perspective of SEB and SEGR in vertical planar MOSFETs as well as provides references/information to other device types that exhibit SEB and SEGR effects.

The radiation effects community has long known that single event transients in digital microcircuits will have an increasing importance on error rates as device sizes shrink. However separating these errors from static errors in latch cells has often proved difficult. Thus determining both the significance and the nature of these transient errors has not been easy. In this study, by utilizing a latch that is radiation hard at static clock frequencies the errors due to transients could be separated. By separating the transient error rate from the static upset error rate, the pulse structure of the propagating transients was studied using SPICE. The implications of these pulsewidths will also be discussed.

We have measured the single-event-transient (SET) width as a function of cross-section over three CMOS bulk/epitaxial technology nodes (0.25, 0.18 and 0.13 mum) using an identically scaled programmable-delay temporal-latch technique. Both the maximum width of the SET pulse and the cross-section are shown to depend primarily on the supply voltage, with a substantial increase in transient width and cross-section with lower operating potentials

A Society of Environmental Toxicology and Chemistry (SETAC) Focused Topic Meeting (FTM) on the environmental management of per- and polyfluoroalkyl substances (PFAS) convened during August 2019 in Durham, North Carolina (USA). Experts from around the globe were brought together to critically evaluate new and emerging information on PFAS including chemistry, fate, transport, exposure, and toxicity. After plenary presentations, breakout groups were established and tasked to identify and adjudicate via panel discussions overarching conclusions and relevant data gaps. The present review is one in a series and summarizes outcomes of presentations and breakout discussions related to (1) primary sources and pathways in the environment, (2) sorption and transport in porous media, (3) precursor transformation, (4) practical approaches to the assessment of source zones, (5) standard and novel analytical methods with implications for environmental forensics and site management, and (6) classification and grouping from multiple perspectives. Outcomes illustrate that PFAS classification will continue to be a challenge, and additional pressing needs include increased availability of analytical standards and methods for assessment of PFAS and fate and transport, including precursor transformation. Although the state of the science is sufficient to support a degree of site-specific and flexible risk management, effective source prioritization tools, predictive fate and transport models, and improved and standardized analytical methods are needed to guide broader policies and best management practices. Environ Toxicol Chem 2021;40:3234-3260. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

This paper is concerned with the in-field autonomous operation of unmanned marine vehicles in accordance with convention for safe and proper collision avoidance as prescribed by the Coast Guard Collision Regulations (COLREGS). These rules are written to train and guide safe human operation of marine vehicles and are heavily dependent on human common sense in determining rule applicability as well as rule execution, especially when multiple rules apply simultaneously. To capture, the flexibility exploited by humans, this work applies a novel method of multiobjective optimization, interval programming, in a behavior-based control framework for representing the navigation rules, as well as task behaviors, in a way that achieves simultaneous optimal satisfaction. We present experimental validation of this approach using multiple autonomous surface craft. This work represents the first in-field demonstration of multiobjective optimization applied to autonomous COLREGS-based marine vehicle navigation. © 2006 Wiley Periodicals, Inc.

Freeze-dried bone allografts (FDBAs) were evaluated alone and in combination with various types of autogenous bone in the treatment of periodontal osseous defects. A total of 381 defects were evaluated by surgical reentry approximately 1 year after grafting. Reentry data were compared with similar data obtained when the grafts were placed. Osseous regeneration and pocket reduction were rated as complete, greater than 50%, less than 50%, or failed. Complete or greater than 50% regeneration was considered successful. When compared with FDBAs, composite freeze-dried bone allografts/autogenous bone grafts (FDBA/ABGs) appear to offer significantly improved results in both osseous regeneration and pocket reduction. Use of composite FDBA/ABGs resulted in significant improvement in the treatment of combination one/two-wall defects and furcation involvements. A trend of improvement was seen with two-wall defects. The surgical data indicated that complete wound closure and the use of antibiotics enhanced graft success. The results also indicated that the presence of endodontically obturated teeth may be a consideration in the success or failure of the graft.

Single-event transients (SETs) in digital circuits/processes are examined. SETs appear to substantially mitigate traditional SEU static-latch hardening techniques below 0.25 /spl mu/m. The resulting IC error rate for advanced technology node hardened-electronics is dominated by the combinational-logic SET rate.