Underwater inverse LIBS (iLIBS) for marine archaeology

Science.gov (United States)

Asmus, J.; Magde, M.; Elford, J.; Magde, D.; Parfenov, V.

2013-05-01

In recent years there have been enormous advances in nautical archaeology through developments in SONAR technologies as well as in manned and robotic submersible vehicles. The number of sunken vessel discoveries has escalated in many of the seas of the world in response to the widespread application of these and other new tools. Customarily, surviving artifacts within the debris field of a wreck are collected and then moved to laboratories, centers, or institutions for analyses and possible conservation. Frequently, the conservation phase involves chemical treatments to stabilize an artefact to standard temperature, pressure, and humidity instead of an undersea environment. Many of the artefacts encountered at an underwater site are now characterized and restored in-situ in accordance with modern trends in art conservation. Two examples of this trend are exemplified by the resting place of the wreck of the Titanic in the Atlantic and the Cancun Underwater Park in the Caribbean Sea. These two debris fields have been turned into museums for diving visitors. Several research groups have investigated the possibility of adapting the well-established analytical tool Laser Induced Breakdown Spectroscopy (LIBS) to in-situ elemental analyses of underwater cultural, historic, and archaeological artefacts where discovered, rather than as a phase of a salvage operation. As the underwater laser ablation associated with LIBS generates a "snowplough" shockwave within the aqueous matrix, the atomic emission spectrum is usually severely attenuated in escaping from the target. Consequently, probative experiments to date generally invoke a submerged air chamber or air jet to isolate water from the interaction zone as well as employ more complex double-pulse lasers. These measures impose severe logistical constraints on the examination of widely dispersed underwater artefacts. In order to overcome this constraint we report on water-immersion LIBS experiments performed with oblique

Terror weapons. Ridding the world of nuclear, biological and chemical weapons - Commission on mass destruction weapons

International Nuclear Information System (INIS)

Blix, H.; Journe, V.

2010-01-01

This book approaches in 8 chapters the ambitious challenge of ridding the world of all mass destruction weapons: 1 - re-launching disarmament; 2 - terror weapons: nature of threats and answers (weakness of traditional answers, counter-proliferation); 3 - nuclear weapons: preventing proliferation and terrorism, reducing threat and nuclear weapons number, from regulation to banning); 4 - biological or toxin weapons; 5 - chemical weapons; 6 - vectors, anti-missile defenses and space weapons; 7 - exports control, international assistance and non-governmental actors; 8 - respect, verification, enforcement and role of the United Nations. The recommendations and works of the Commission are presented in appendix together with the declaration adopted on April 30, 2009. (J.S.)

Nonuniform Illumination Correction Algorithm for Underwater Images Using Maximum Likelihood Estimation Method

Directory of Open Access Journals (Sweden)

Sonali Sachin Sankpal

2016-01-01

Full Text Available Scattering and absorption of light is main reason for limited visibility in water. The suspended particles and dissolved chemical compounds in water are also responsible for scattering and absorption of light in water. The limited visibility in water results in degradation of underwater images. The visibility can be increased by using artificial light source in underwater imaging system. But the artificial light illuminates the scene in a nonuniform fashion. It produces bright spot at the center with the dark region at surroundings. In some cases imaging system itself creates dark region in the image by producing shadow on the objects. The problem of nonuniform illumination is neglected by the researchers in most of the image enhancement techniques of underwater images. Also very few methods are discussed showing the results on color images. This paper suggests a method for nonuniform illumination correction for underwater images. The method assumes that natural underwater images are Rayleigh distributed. This paper used maximum likelihood estimation of scale parameter to map distribution of image to Rayleigh distribution. The method is compared with traditional methods for nonuniform illumination correction using no-reference image quality metrics like average luminance, average information entropy, normalized neighborhood function, average contrast, and comprehensive assessment function.

Underwater wireless communication system

International Nuclear Information System (INIS)

Goh, J H; Shaw, A; Al-Shamma'a, A I

2009-01-01

Underwater communication has a range of applications including remotely operated vehicle (ROV) and autonomous underwater vehicle (AUV) communication and docking in the offshore industry. Current underwater transmission techniques is primarily utilise sound waves for large distance at lower frequencies and the velocity of sound in water is approximately 1500m/s the resultant communications have problems with multi-path propagation and low bandwidth problems. The use of electromagnetic (EM) techniques underwater has largely been overlooked because of the attenuation due to the conductivity of seawater. However, for short range applications, the higher frequencies and much higher velocity can prove advantageous. This paper will outline a project which will utilise recent investigations that demonstrate EM wave propagation up to the MHz frequency range is possible in seawater.

Underwater Scene Composition

Science.gov (United States)

Kim, Nanyoung

2009-01-01

In this article, the author describes an underwater scene composition for elementary-education majors. This project deals with watercolor with crayon or oil-pastel resist (medium); the beauty of nature represented by fish in the underwater scene (theme); texture and pattern (design elements); drawing simple forms (drawing skill); and composition…

Resources for Underwater Robotics Education

Science.gov (United States)

Wallace, Michael L.; Freitas, William M.

2016-01-01

4-H clubs can build and program underwater robots from raw materials. An annotated resource list for engaging youth in building underwater remotely operated vehicles (ROVs) is provided. This article is a companion piece to the Research in Brief article "Building Teen Futures with Underwater Robotics" in this issue of the "Journal of…

Underwater Coatings for Contamination Control

International Nuclear Information System (INIS)

Julia L. Tripp; Kip Archibald; Ann-Marie Phillips; Joseph Campbell

2004-01-01

The Idaho National Engineering and Environmental Laboratory (INEEL) is deactivating several fuel storage basins. Airborne contamination is a concern when the sides of the basins are exposed and allowed to dry during water removal. One way of controlling this airborne contamination is to fix the contamination in place while the pool walls are still submerged. There are many underwater coatings available on the market that are used in marine, naval and other applications. A series of tests were run to determine whether the candidate underwater fixatives are easily applied and adhere well to the substrates (pool wall materials) found in INEEL fuel pools. The four pools considered included (1) Test Area North (TAN-607) with epoxy painted concrete walls; (2) Idaho Nuclear Technology and Engineering Center (INTEC) (CPP-603) with bare concrete walls; (3) Materials Test Reactor (MTR) Canal with stainless steel lined concrete walls; and (4) Power Burst Facility (PBF-620) with stainless steel lined concrete walls on the bottom and epoxy painted carbon steel lined walls on the upper portions. Therefore, the four materials chosen for testing included bare concrete, epoxy painted concrete, epoxy painted carbon steel, and stainless steel. The typical water temperature of the pools varies from 55 F to 80 F dependent on the pool and the season. These tests were done at room temperature. The following criteria were used during this evaluation. The underwater coating must: (1) Be easy to apply; (2) Adhere well to the four surfaces of interest; (3) Not change or have a negative impact on water chemistry or clarity; (4) Not be hazardous in final applied form; and (5) Be proven in other underwater applications. In addition, it is desirable for the coating to have a high pigment or high cross-link density to prevent radiation from penetrating. This paper will detail the testing completed and the test results. A proprietary two-part, underwater epoxy owned by S. G. Pinney and Associates

A new technique for robot vision in autonomous underwater vehicles using the color shift in underwater imaging

Science.gov (United States)

2017-06-01

FOR ROBOT VISION IN AUTONOMOUS UNDERWATER VEHICLES USING THE COLOR SHIFT IN UNDERWATER IMAGING by Jake A. Jones June 2017 Thesis Advisor...techniques to determine the distances from each pixel to the camera. 14. SUBJECT TERMS unmanned undersea vehicles (UUVs), autonomous ... AUTONOMOUS UNDERWATER VEHICLES USING THE COLOR SHIFT IN UNDERWATER IMAGING Jake A. Jones Lieutenant Commander, United States Navy B.S

Stability analysis of hybrid-driven underwater glider

Science.gov (United States)

Niu, Wen-dong; Wang, Shu-xin; Wang, Yan-hui; Song, Yang; Zhu, Ya-qiang

2017-10-01

Hybrid-driven underwater glider is a new type of unmanned underwater vehicle, which combines the advantages of autonomous underwater vehicles and traditional underwater gliders. The autonomous underwater vehicles have good maneuverability and can travel with a high speed, while the traditional underwater gliders are highlighted by low power consumption, long voyage, long endurance and good stealth characteristics. The hybrid-driven underwater gliders can realize variable motion profiles by their own buoyancy-driven and propeller propulsion systems. Stability of the mechanical system determines the performance of the system. In this paper, the Petrel-II hybrid-driven underwater glider developed by Tianjin University is selected as the research object and the stability of hybrid-driven underwater glider unitedly controlled by buoyancy and propeller has been targeted and evidenced. The dimensionless equations of the hybrid-driven underwater glider are obtained when the propeller is working. Then, the steady speed and steady glide path angle under steady-state motion have also been achieved. The steady-state operating conditions can be calculated when the hybrid-driven underwater glider reaches the desired steady-state motion. And the steadystate operating conditions are relatively conservative at the lower bound of the velocity range compared with the range of the velocity derived from the method of the composite Lyapunov function. By calculating the hydrodynamic coefficients of the Petrel-II hybrid-driven underwater glider, the simulation analysis has been conducted. In addition, the results of the field trials conducted in the South China Sea and the Danjiangkou Reservoir of China have been presented to illustrate the validity of the analysis and simulation, and to show the feasibility of the method of the composite Lyapunov function which verifies the stability of the Petrel-II hybrid-driven underwater glider.

The weapons effect.

Science.gov (United States)

Benjamin, Arlin James; Bushman, Brad J

2018-02-01

In some societies, weapons are plentiful and highly visible. This review examines recent trends in research on the weapons effect, which is the finding that the mere presence of weapons can prime people to behave aggressively. The General Aggression Model provides a theoretical framework to explain why the weapons effect occurs. This model postulates that exposure to weapons increases aggressive thoughts and hostile appraisals, thus explaining why weapons facilitate aggressive behavior. Data from meta-analytic reviews are consistent with the General Aggression Model. These findings have important practical as well as theoretical implications. They suggest that the link between weapons and aggression is very strong in semantic memory, and that merely seeing a weapon can make people more aggressive. Copyright © 2017 Elsevier Ltd. All rights reserved.

Weapon Simulator Test Methodology Investigation: Comparison of Live Fire and Weapon Simulator Test Methodologies and the Effects of Clothing and Individual Equipment on Marksmanship

Science.gov (United States)

2016-09-15

variables analyzed included shot group tightness, radial error from the center of the target, and multiple time variables. The weapon simulator and...performance could be analyzed to determine if the weapon simulator data aligns with live fire data (i.e., if similar performance decrements appear in the...Analysis and Reporting The Noptel NOS4 software records shot performance data real-time and presents multiple statistical calculations as well as

ROV Based Underwater Blurred Image Restoration

Institute of Scientific and Technical Information of China (English)

LIU Zhishen; DING Tianfu; WANG Gang

2003-01-01

In this paper, we present a method of ROV based image processing to restore underwater blurry images from the theory of light and image transmission in the sea. Computer is used to simulate the maximum detection range of the ROV under different water body conditions. The receiving irradiance of the video camera at different detection ranges is also calculated. The ROV's detection performance under different water body conditions is given by simulation. We restore the underwater blurry images using the Wiener filter based on the simulation. The Wiener filter is shown to be a simple useful method for underwater image restoration in the ROV underwater experiments. We also present examples of restored images of an underwater standard target taken by the video camera in these experiments.

Chemical and biological weapons: new questions, new answers.

Science.gov (United States)

Hood, E

1999-01-01

The words "chemical and biological weapons" (CBW) send a shiver down most spines these days. With the end of the Cold War, the possibility of a massive nuclear confrontation appears remote, so today many popular doomsday scenarios center on the aggressive use of chemical or biological warfare by rogue nations or terrorist groups. As exaggerated as some of the accounts are, with CBW cast as the latest unseen, unstoppable enemy, the threat posed by these weapons is all too real, and growing. Images p931-a PMID:10585899

Underwater 3D filming

Directory of Open Access Journals (Sweden)

Roberto Rinaldi

2014-12-01

Full Text Available After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space (“Gravity” and the underwater realm look perfect to be reproduced in 3D. “Filming in space” was possible in “Gravity” using special effects and computer graphic. The underwater realm is still difficult to be handled. Underwater filming in 3D was not that easy and effective as filming in 2D, since not long ago. After almost 3 years of research, a French, Austrian and Italian team realized a perfect tool to film underwater, in 3D, without any constrains. This allows filmmakers to bring the audience deep inside an environment where they most probably will never have the chance to be.

Sandia National Laboratories: Microsystems Science & Technology Center

Science.gov (United States)

Environmental Management System Pollution Prevention History 60 impacts Diversity Locations Facts & Figures Programs Nuclear Weapons About Nuclear Weapons Safety & Security Weapons Science & Technology Robotics R&D 100 Awards Laboratory Directed Research & Development Technology Deployment Centers

Underwater welding of steel

International Nuclear Information System (INIS)

Ibarra, S.; Olson, D.L.

1992-01-01

A fundamental basis to understand the behavior of wet underwater welding of steel is introduced. Both the pyrometallurgical and physical metallurgy concepts are discussed. Modifications of welding consumables and practice are suggested. This chapter promotes further contributions of meatllurgical research to improve and promote wet underwater welding. (orig.)

Colour reconstruction of underwater images

OpenAIRE

Hoth, Julian; Kowalczyk, Wojciech

2017-01-01

Objects look very different in the underwater environment compared to their appearance in sunlight. Images with correct colouring simplify the detection of underwater objects and may allow the use of visual SLAM algorithms developed for land-based robots underwater. Hence, image processing is required. Current algorithms focus on the colour reconstruction of scenery at diving depth where different colours can still be distinguished. At greater depth this is not the case. In this study it is i...

Quantum imaging for underwater arctic navigation

Science.gov (United States)

Lanzagorta, Marco

2017-05-01

The precise navigation of underwater vehicles is a difficult task due to the challenges imposed by the variable oceanic environment. It is particularly difficult if the underwater vehicle is trying to navigate under the Arctic ice shelf. Indeed, in this scenario traditional navigation devices such as GPS, compasses and gyrocompasses are unavailable or unreliable. In addition, the shape and thickness of the ice shelf is variable throughout the year. Current Arctic underwater navigation systems include sonar arrays to detect the proximity to the ice. However, these systems are undesirable in a wartime environment, as the sound gives away the position of the underwater vehicle. In this paper we briefly describe the theoretical design of a quantum imaging system that could allow the safe and stealthy navigation of underwater Arctic vehicles.

Flexible weapons architecture design

Science.gov (United States)

Pyant, William C., III

Present day air-delivered weapons are of a closed architecture, with little to no ability to tailor the weapon for the individual engagement. The closed architectures require weaponeers to make the target fit the weapon instead of fitting the individual weapons to a target. The concept of a flexible weapons aims to modularize weapons design using an open architecture shell into which different modules are inserted to achieve the desired target fractional damage while reducing cost and civilian casualties. This thesis shows that the architecture design factors of damage mechanism, fusing, weapons weight, guidance, and propulsion are significant in enhancing weapon performance objectives, and would benefit from modularization. Additionally, this thesis constructs an algorithm that can be used to design a weapon set for a particular target class based on these modular components.

Nuclear weapons modernizations

Energy Technology Data Exchange (ETDEWEB)

Kristensen, Hans M. [Federation of American Scientists, Washington, DC (United States)

2014-05-09

This article reviews the nuclear weapons modernization programs underway in the world's nine nuclear weapons states. It concludes that despite significant reductions in overall weapons inventories since the end of the Cold War, the pace of reductions is slowing - four of the nuclear weapons states are even increasing their arsenals, and all the nuclear weapons states are busy modernizing their remaining arsenals in what appears to be a dynamic and counterproductive nuclear competition. The author questions whether perpetual modernization combined with no specific plan for the elimination of nuclear weapons is consistent with the nuclear Non-Proliferation Treaty and concludes that new limits on nuclear modernizations are needed.

Autonomous Underwater Gliders

OpenAIRE

Wood,; Stephen,

2009-01-01

Autonomous Underwater Vehicles are only now being marketed as robust commercial vehicles for many industries, and of these vehicles underwater gliders are becoming the new tool for oceanographers. Satellites have provided scientists and marine specialists with measurements of the sea surface such as temperature since the late 1970s, and data via subsurface oceanographic moorings since the 1950's. As stated by David Smeed of the National Oceanography Centre, Southampton, England, that "gliders...

Flexible weapons architecture design

OpenAIRE

Pyant, William C.

2015-01-01

Present day air-delivered weapons are of a closed architecture, with little to no ability to tailor the weapon for the individual engagement. The closed architectures require weaponeers to make the target fit the weapon instead of fitting the individual weapons to a target. The concept of a flexible weapons aims to modularize weapons design using an open architecture shell into which different modules are inserted to achieve the desired target fractional damage while reducing cost and civilia...

Underwater welding using remote controlled robots. Development of remote underwater welding technology with a high power YAG laser

International Nuclear Information System (INIS)

Miwa, Yasuhiro; Sato, Syuuichi; Kojima, Toshio; Owaki, Katsura; Hirose, Naoya

2002-01-01

As components in nuclear power plant have been periodically carried out their inspection and repair to keep their integrity, on radioactive liquid wastes storage facility, because of difficulty on their inspection by human beings, some are remained without inspection, and even when capable of inspection, conversion from human works to remote operations is desired from a viewpoint of their operation efficiency upgrading. For response to these needs, some developments on a technology capable of carrying out inspection of their inside at underwater environment and repairing welding with YAG laser by means of remote operation, have been performed. Remote underwater inspection and repair technology is a combination technology of already applied underwater mobile technique (underwater inspection robot) with underwater YAG laser welding technique which is recently at actual using level. Therefore, this technology is composed of an inspection robot and a repair welding robot. And, testing results using the underwater inspection robot and welding test results using the underwater repair welding robot, were enough preferable to obtain forecasting applicable to actual apparatuses. This technology is especially effective for inspection and repair of inside of nuclear fuel cycle apparatuses and relatively high dose apparatuses, and can be thought to be applicable also to large capacity tanks, tanks dealing with harmful matters, underwater structures, and so on, in general industries. (G.K.)

Hematologic evaluation of employees with leukopenia. Naval Weapons Center, China Lake, California.

Science.gov (United States)

Luiken, G A; Marsh, W L; Heath, V C; Long, H L; Weatherly, T L; Seal, G M

1988-12-01

Evaluation of 86 employees with a history of leukopenia at the Naval Weapons Center (NWC), China Lake, California, was done by exposure questionnaires, medical histories, physical examinations, peripheral blood smear, and bone marrow evaluations, including morphologic examination, stem cell culture, and cytogenetics. Forty-eight subjects were found to be leukopenic at the time of the study, and two subjects were found to have hairy cell leukemia. All subjects had positive exposure histories and were healthy at the time of the study. Review of peripheral smears identified the patients with marrow abnormalities. Bone marrow cultures revealed several patients with possible marrow suppression. Chromosome studies were not diagnostic. Five-year follow-up health questionnaires revealed no significant health problems; the two workers with hairy cell leukemia are alive and fully functional. Leukopenia in itself does not appear to be a risk factor for poor health, and it is unknown whether or not it may be a useful screening tool to identify workers at risk in toxic environments. Careful evaluation of blood cell counts and peripheral smears should be sufficient to identify people with potential marrow abnormalities.

Underwater Acoustic Networking Techniques

CERN Document Server

Otnes, Roald; Casari, Paolo; Goetz, Michael; Husøy, Thor; Nissen, Ivor; Rimstad, Knut; van Walree, Paul; Zorzi, Michele

2012-01-01

This literature study presents an overview of underwater acoustic networking. It provides a background and describes the state of the art of all networking facets that are relevant for underwater applications. This report serves both as an introduction to the subject and as a summary of existing protocols, providing support and inspiration for the development of network architectures.

OFDM for underwater acoustic communications

CERN Document Server

Zhou, Shengli

2014-01-01

A blend of introductory material and advanced signal processing and communication techniques, of critical importance to underwater system and network development This book, which is the first to describe the processing techniques central to underwater OFDM, is arranged into four distinct sections: First, it describes the characteristics of underwater acoustic channels, and stresses the difference from wireless radio channels. Then it goes over the basics of OFDM and channel coding. The second part starts with an overview of the OFDM receiver, and develops various modules for the receiver des

Underwater Acoustic Tracer System

Science.gov (United States)

2009-03-13

for controlling and utilizing supercavitating projectile dynamics to produce a distinctive radiated noise signal. (2) Description of the Prior Art...metallic objects which travel relatively closely to a magnetic pickup. For larger, high speed, underwater projectiles, supercavitating underwater vehicles...have been proposed for use. The conditions for supercavitation are known in the art. Supercavitation allows for higher speeds to be sustainable

Human Factors Issues When Operating Underwater Remotely Operated Vehicles and Autonomous Underwater Vehicles

Science.gov (United States)

2011-03-01

etiquette (Parasuraman & Miller, 2004). Through natural and intuitive communication, Johnson et al., (2007) hope that this interface will instill greater...and etiquette in high criticality automated systems. Communications of the ACM, 47(4), 51-55. Parasuraman, R., & Riley, V. (1997). Humans and... protocols for underwater wireless communications. IEEE Communications Magazine, pp. 97-102. Quazi, A. H., & Konrad, W. L. (1982, March 1982). Underwater

Determining spherical lens correction for astronaut training underwater.

Science.gov (United States)

Porter, Jason; Gibson, C Robert; Strauss, Samuel

2011-09-01

To develop a model that will accurately predict the distance spherical lens correction needed to be worn by National Aeronautics and Space Administration astronauts while training underwater. The replica space suit's helmet contains curved visors that induce refractive power when submersed in water. Anterior surface powers and thicknesses were measured for the helmet's protective and inside visors. The impact of each visor on the helmet's refractive power in water was analyzed using thick lens calculations and Zemax optical design software. Using geometrical optics approximations, a model was developed to determine the optimal distance spherical power needed to be worn underwater based on the helmet's total induced spherical power underwater and the astronaut's manifest spectacle plane correction in air. The validity of the model was tested using data from both eyes of 10 astronauts who trained underwater. The helmet's visors induced a total power of -2.737 D when placed underwater. The required underwater spherical correction (FW) was linearly related to the spectacle plane spherical correction in air (FAir): FW = FAir + 2.356 D. The mean magnitude of the difference between the actual correction worn underwater and the calculated underwater correction was 0.20 ± 0.11 D. The actual and calculated values were highly correlated (r = 0.971) with 70% of eyes having a difference in magnitude of astronauts. The model accurately predicts the actual values worn underwater and can be applied (more generally) to determine a suitable spectacle lens correction to be worn behind other types of masks when submerged underwater.

Bibliography, subject index, and author index of the literature examined by the Radiation Shielding Information Center (Reactor and Weapons Radiation Shielding)

International Nuclear Information System (INIS)

1978-01-01

An indexed bibliography is presented of literature selected by the Radiation Shielding Information Center since the previous volume was published in 1974 in the area of radiation transport and shielding against radiation from nuclear reactors, x-ray machines, radioisotopes, nuclear weapons (including fallout), and low-energy accelerators (e.g., neutron generators). In addition to lists of literature titles by subject categories (accessions 3501-4950), author and keyword indexes are given. Most of the literature selected for Vol. V was published in the years 1973 to 1976

Dynamics and Control of Underwater Gliders I: Steady Motions

OpenAIRE

Mahmoudian, N.; Geisbert, J.; Woolsey, C.

2007-01-01

This paper describes analysis of steady motions for underwater gliders, a type of highly efficient underwater vehicle which uses gravity for propulsion. Underwater gliders are winged underwater vehicles which locomote by modulating their buoyancy and their attitude. Several such vehicles have been developed and have proven their worth as efficient long-distance, long-duration ocean sampling platforms. To date, the primary emphasis in underwater glider development has been on locomotive effici...

Underwater welding and repair technologies applied in PWR environment

International Nuclear Information System (INIS)

Scandella, Fabrice; Carpreau, Jean-Michel

2012-01-01

The authors describe several welding processes and technologies which have been used for underwater applications and which can be applied when repairing components of a PWR type reactor. They address, describe and discuss wet arc welding processes, the peculiarities of underwater welding, and the use of various processes such as 111, 114 and 135 processes, underwater welding with the hybrid plasma MIG-MAG process, underwater welding with the laser wire process, underwater welding with the FSW, FSP or UWFSW processes, underwater welding with variants of the friction welding process (friction surfacing, taper stitch welding, hydro-pillar processing

The weapons effect

NARCIS (Netherlands)

Benjamin, Arlin James; Bushman, Brad J.

In some societies, weapons are plentiful and highly visible. This review examines recent trends in research on the weapons effect, which is the finding that the mere presence of weapons can prime people to behave aggressively. The General Aggression Model provides a theoretical framework to explain

Human Injury Criteria for Underwater Blasts.

Directory of Open Access Journals (Sweden)

Rachel M Lance

Full Text Available Underwater blasts propagate further and injure more readily than equivalent air blasts. Development of effective personal protection and countermeasures, however, requires knowledge of the currently unknown human tolerance to underwater blast. Current guidelines for prevention of underwater blast injury are not based on any organized injury risk assessment, human data or experimental data. The goal of this study was to derive injury risk assessments for underwater blast using well-characterized human underwater blast exposures in the open literature. The human injury dataset was compiled using 34 case reports on underwater blast exposure to 475 personnel, dating as early as 1916. Using severity ratings, computational reconstructions of the blasts, and survival information from a final set of 262 human exposures, injury risk models were developed for both injury severity and risk of fatality as functions of blast impulse and blast peak overpressure. Based on these human data, we found that the 50% risk of fatality from underwater blast occurred at 302±16 kPa-ms impulse. Conservatively, there is a 20% risk of pulmonary injury at a kilometer from a 20 kg charge. From a clinical point of view, this new injury risk model emphasizes the large distances possible for potential pulmonary and gut injuries in water compared with air. This risk value is the first impulse-based fatality risk calculated from human data. The large-scale inconsistency between the blast exposures in the case reports and the guidelines available in the literature prior to this study further underscored the need for this new guideline derived from the unique dataset of actual injuries in this study.

Combating the terrorist use of mass destruction weapons, particularly nuclear weapons

International Nuclear Information System (INIS)

Barakat, M.

2008-01-01

The risks of mass destruction weapons vary and also forms of damages resulting therefrom. While the effects of nuclear weapons are focused, sudden and comprehensive, the chemical weapons have limited impacts relatively unless used intensively severe prejudice to the element of surprise, and thus impaired the efficacy of their influences,especially that they affect exceptionally the individuals in the area of injury and biological weapons do not announce themselves except through their effect that appears later than the time of use as they affect exceptionally the organisms in the area of injury.The mass destruction weapons have turned from being a purely military means in the early twentieth century and have now become the means of violence against governments and countries that they should prepare themselves for and respond in ways of successful and effective countermeasures. Despite the fact that the acquisition of mass destruction weapons can be considered as a priority objective, which terrorist groups and organizations steadily seek but their accessibility is flanked by a lot of difficulties. Addressing the risk of further spread of nuclear weapons, and especially after doubling the power of those high-risk weapons, the international community has an approach to take a number of arrangements that complement each other to control and resist nuclear proliferation, either for the states or for terrorist groups.

Stability of transition to a world without nuclear weapons: Technical problems of verification

International Nuclear Information System (INIS)

Zhigalov, V.

1998-01-01

A serious psychological barrier to acceptance of the concept for achieving the nuclear-weapon-free world is fear of facing the prospect that one or more nations or extremist political groups might develop their own nuclear weapons. Actually this is a question of stability of the nuclear-weapon-free world. From this point of view the most effective system of verification is an absolute necessity. This system must ensure detection of so called undeclared nuclear activity at early stage. Scientists of Russian nuclear centers are working today on solving this problem. This paper is considered to be a comprehensive attempt to analyze the technical and organizational aspects of the problems of transition to a nuclear-weapons-free world, setting aside the difficulties of resolving purely political problems

Underwater Gliders by Dr. Kevin Smith [video

OpenAIRE

Naval Postgraduate School Physics

2015-01-01

NPS Physics NPS Physics Research Projects Underwater glider research is currently underway in the physics department at the naval postgraduate in Monterey Ca. Dr. Kevin Smith is a specialist in underwater acoustics and sonar systems. He and his team are currently focused on autonomous underwater gliders and developing systems capable of detecting parameters in the ocean and listening for various sources of sound.

Testing of an underwater remotely-operated vehicle in the basins of the Cattenom nuclear power generation center

International Nuclear Information System (INIS)

Delfour, D.; Khakanski, M.; Nepveu, C.; Schmitt, J.

1993-05-01

An underwater robot was tested in the basins of the Cattenom Nuclear Power Generation Center fed with raw water from the Moselle River. The purpose was to inspect wall biofouling without interrupting water circulation. The ROV is a light, compact device, remotely controlled by cable and equipped with video cameras. The video recordings made were used to compare conditions in a basin cleaned the previous month by divers with those in a basin which had not been cleaned for a year. Manual cleaning by divers is an effective method, leaving Zebra Mussels on less than 5% of the wall surfaces. On the other hand, the floor of the basin was observed to be covered with fine sediment, vegetal matters and shells washed in with the Moselle River water. In the basin which had not been cleaned, the entire wall surface was covered with very dense tufts of tubular organisms (Hydrozoa Cordylophora) and zebra mussels. The tests have provided elements for definition of an inspection procedure and have given rise to suggestions for complementary equipment. (authors). 5 figs., 9 photos

Why are U.S. nuclear weapon modernization efforts controversial?

Science.gov (United States)

Acton, James

2016-03-01

U.S. nuclear weapon modernization programs are focused on extending the lives of existing warheads and developing new delivery vehicles to replace ageing bombers, intercontinental ballistic missiles, and ballistic missile submarines. These efforts are contested and controversial. Some critics argue that they are largely unnecessary, financially wasteful and potentially destabilizing. Other critics posit that they do not go far enough and that nuclear weapons with new military capabilities are required. At its core, this debate centers on three strategic questions. First, what roles should nuclear weapons be assigned? Second, what military capabilities do nuclear weapons need to fulfill these roles? Third, how severe are the unintended escalation risks associated with particular systems? Proponents of scaled-down modernization efforts generally argue for reducing the role of nuclear weapons but also that, even under existing policy, new military capabilities are not required. They also tend to stress the escalation risks of new--and even some existing--capabilities. Proponents of enhanced modernization efforts tend to advocate for a more expansive role for nuclear weapons in national security strategy. They also often argue that nuclear deterrence would be enhanced by lower yield weapons and/or so called bunker busters able to destroy more deeply buried targets. The debate is further fueled by technical disagreements over many aspects of ongoing and proposed modernization efforts. Some of these disagreements--such as the need for warhead life extension programs and their necessary scope--are essentially impossible to resolve at the unclassified level. By contrast, unclassified analysis can help elucidate--though not answer--other questions, such as the potential value of bunker busters.

Underwater Ranging

OpenAIRE

S. P. Gaba

1984-01-01

The paper deals with underwater laser ranging system, its principle of operation and maximum depth capability. The sources of external noise and methods to improve signal-to-noise ratio are also discussed.

UNDERWATER COATINGS FOR CONTAMINATION CONTROL

International Nuclear Information System (INIS)

Julia L. Tripp; Kip Archibald; Ann Marie Phillips; Joseph Campbell

2004-01-01

The Idaho National Laboratory (INL) deactivated several aging nuclear fuel storage basins. Planners for this effort were greatly concerned that radioactive contamination present on the basin walls could become airborne as the sides of the basins became exposed during deactivation and allowed to dry after water removal. One way to control this airborne contamination was to fix the contamination in place while the pool walls were still submerged. There are many underwater coatings available on the market for marine, naval and other applications. A series of tests were run to determine whether the candidate underwater fixatives were easily applied and adhered well to the substrates (pool wall materials) found in INL fuel pools. Lab-scale experiments were conducted by applying fourteen different commercial underwater coatings to four substrate materials representative of the storage basin construction materials, and evaluating their performance. The coupons included bare concrete, epoxy painted concrete, epoxy painted carbon steel, and stainless steel. The evaluation criteria included ease of application, adherence to the four surfaces of interest, no change on water clarity or chemistry, non-hazardous in final applied form and be proven in underwater applications. A proprietary two-part, underwater epoxy owned by S. G. Pinney and Associates was selected from the underwater coatings tested for application to all four pools. Divers scrubbed loose contamination off the basin walls and floors using a ship hull scrubber and vacuumed up the sludge. The divers then applied the coating using a special powered roller with two separate heated hoses that allowed the epoxy to mix at the roller surface was used to eliminate pot time concerns. The walls were successfully coated and water was removed from the pools with no detectable airborne contamination releases

Underwater Gliders: A Review

OpenAIRE

Javaid Muhammad Yasar; Ovinis Mark; Nagarajan T; Hashim Fakhruldin B M

2014-01-01

Underwater gliders are a type of underwater vehicle that transverse the oceans by shifting its buoyancy, during which its wings develop a component of the downward motion in the horizontal plane, thus producing a forward force. They are primarily used in oceanography sensing and data collection and play an important role in ocean research and development. Although there have been considerable developments in these gliders since the development of the first glider concept in 1989, to date, no ...

Underwater Calibration of Dome Port Pressure Housings

Science.gov (United States)

Nocerino, E.; Menna, F.; Fassi, F.; Remondino, F.

2016-03-01

Underwater photogrammetry using consumer grade photographic equipment can be feasible for different applications, e.g. archaeology, biology, industrial inspections, etc. The use of a camera underwater can be very different from its terrestrial use due to the optical phenomena involved. The presence of the water and camera pressure housing in front of the camera act as additional optical elements. Spherical dome ports are difficult to manufacture and consequently expensive but at the same time they are the most useful for underwater photogrammetry as they keep the main geometric characteristics of the lens unchanged. Nevertheless, the manufacturing and alignment of dome port pressure housing components can be the source of unexpected changes of radial and decentring distortion, source of systematic errors that can influence the final 3D measurements. The paper provides a brief introduction of underwater optical phenomena involved in underwater photography, then presents the main differences between flat and dome ports to finally discuss the effect of manufacturing on 3D measurements in two case studies.

[Chemical weapons and chemical terrorism].

Science.gov (United States)

Nakamura, Katsumi

2005-10-01

Chemical Weapons are kind of Weapons of Mass Destruction (WMD). They were used large quantities in WWI. Historically, large quantities usage like WWI was not recorded, but small usage has appeared now and then. Chemical weapons are so called "Nuclear weapon for poor countrys" because it's very easy to produce/possession being possible. They are categorized (1) Nerve Agents, (2) Blister Agents, (3) Cyanide (blood) Agents, (4) Pulmonary Agents, (5) Incapacitating Agents (6) Tear Agents from the viewpoint of human body interaction. In 1997 the Chemical Weapons Convention has taken effect. It prohibits chemical weapons development/production, and Organization for the Prohibition of Chemical Weapons (OPCW) verification regime contributes to the chemical weapons disposal. But possibility of possession/use of weapons of mass destruction by terrorist group represented in one by Matsumoto and Tokyo Subway Sarin Attack, So new chemical terrorism countermeasures are necessary.

Bibliography, subject index, and author index of the literature examined by the radiation shielding information center. Volume 6. Reactor and weapons radiation shielding

International Nuclear Information System (INIS)

1980-05-01

An indexed bibliography is presented of literature selected by the Radiation Shielding Information Center since the previous volume was published in 1978 in the area of radiation transport and shielding against radiation from nuclear reactors, x-ray machines, radioisotopes, nuclear weapons (including fallout), and low energy accelerators (e.g., neutron generators). The bibliography was typeset from data processed by computer from magnetic tape files. In addition to lists of literature titles by subject categories (accessions 4951-6200), an author index is given

Youths Carrying a Weapon or Using a Weapon in a Fight: What Makes the Difference?

Science.gov (United States)

Thurnherr, Judit; Michaud, Pierre-Andre; Berchtold, Andre; Akre, Christina; Suris, Joan-Carles

2009-01-01

The objective of this study was to characterize weapon-carrying adolescents and to assess whether weapon carriers differ from weapon users. Data were drawn from a cross-sectional school-based survey of 7548 adolescents aged 16-20 years in Switzerland. Youths carrying a weapon were compared with those who do not. Subsequently, weapon carriers were…

Recoil Considerations for Shoulder-Fired Weapons

Science.gov (United States)

2012-05-01

than would be deduced from the force levels defined by the pressure-time curve of the cartridge. Further and just like a large-caliber weapon mounted...force. If each of the force curves over the time interval were integrated, the result should be the same as that derived from a ballistic pendulum...Kathe, E.; Dillon, R. Sonic Rarefaction Wave Low Recoil Gun; Report ARCCB-TR-2001; U.S. Army Armament Research, Development, and Engineering Center

Underwater 3D filming

OpenAIRE

Rinaldi, Roberto

2014-01-01

After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space (“Gravity” ) and the underwater realm look perfect to be reproduced in 3D. “Filming in space” was possible in “Gravity” using special effects and computer graphic. The underwater realm is still difficult to be handled. Unde...

Perceived popularity of adolescents who use weapons in violence and adolescents who only carry weapons.

Science.gov (United States)

Wallace, Lacey N

2017-01-01

Prior research has found that persistently delinquent youth or more violent youth were less popular than their less delinquent peers (Young, 2013). However, recent research has also found that weapon carrying is associated with being more popular in adolescence (Dijkstra et al., 2010). The present paper examines the perceived popularity of adolescents who carry weapons in comparison to those who both carry and use weapons in acts of violence or threatened violence. Data consist of two waves from the National Longitudinal Study of Adolescent to Adult Health. Analyses use OLS regression with lagged predictors. This paper found no differences in number of friends between weapon carriers and weapon users. However, among both male and female gang members, those who did not use or carry weapons (abstainers) named significantly fewer friends than weapon users. Among females, weapon abstainers both named and were named by significantly more people than weapon users. These differences were not observed for males. Implications of these results and directions for future research are discussed.

Defining Weapons of Mass Destruction

Science.gov (United States)

2012-01-01

Cyprus, Liberia, Malta, Marshall Islands , Mongolia, Panama, and St. Vin- cent and the Grenadines, according to a State Department summary available...1972 Biological and Toxin Weapons Convention, and the 1993 Chemical Weapons Convention. As such, NBC weapons represent a group of weapons that the...Development, Produc- tion and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on Their Destruction contains two references to WMD

Nonstrategic Nuclear Weapons

Science.gov (United States)

2017-02-21

of their nonstrategic nuclear weapons and eliminate many of them. These 1991 announcements, coming after the abortive coup in Moscow in July 1991...of these weapons. The abortive coup in Moscow in August 1991 had also caused alarms about the strength of central control over nuclear weapons...assure other allies of the U.S. commitment to their security, but these assurances do not necessarily include legally binding commitments to retaliate

Virtual nuclear weapons

Energy Technology Data Exchange (ETDEWEB)

Pilat, J.F.

1997-08-01

The term virtual nuclear weapons proliferation and arsenals, as opposed to actual weapons and arsenals, has entered in recent years the American lexicon of nuclear strategy, arms control, and nonproliferation. While the term seems to have an intuitive appeal, largely due to its cyberspace imagery, its current use is still vague and loose. The author believes, however, that if the term is clearly delineated, it might offer a promising approach to conceptualizing certain current problems of proliferation. The first use is in a reference to an old problem that has resurfaced recently: the problem of growing availability of weapon-usable nuclear materials in civilian nuclear programs along with materials made `excess` to defense needs by current arms reduction and dismantlement. It is argued that the availability of these vast materials, either by declared nuclear-weapon states or by technologically advanced nonweapon states, makes it possible for those states to rapidly assemble and deploy nuclear weapons. The second use has quite a different set of connotations. It is derived conceptually from the imagery of computer-generated reality. In this use, one thinks of virtual proliferation and arsenals not in terms of the physical hardware required to make the bomb but rather in terms of the knowledge/experience required to design, assemble, and deploy the arsenal. Virtual weapons are a physics reality and cannot be ignored in a world where knowledge, experience, materials, and other requirements to make nuclear weapons are widespread, and where dramatic army reductions and, in some cases, disarmament are realities. These concepts are useful in defining a continuum of virtual capabilities, ranging from those at the low end that derive from general technology diffusion and the existence of nuclear energy programs to those at the high end that involve conscious decisions to develop or maintain militarily significant nuclear-weapon capabilities.

IVO develops a new repair technique for underwater sites. Viscous doughlike substance underwater cracks

Energy Technology Data Exchange (ETDEWEB)

Klingstedt, G.; Leisio, C. [ed.

1998-07-01

A viscous sealant is revolutionizing repair of the stone and concrete masonry of underwater dams, bridges and canals. There is now no need for expensive and time-consuming cofferdams, since a diver can extrude quick-setting mortar into underwater structures needing repair. This technique has worked well in recent years in various parts of Finland even in strongly flowing water. IVO experts are now starting to look more beyond the borders of Finland

A man-made object detection for underwater TV

Science.gov (United States)

Cheng, Binbin; Wang, Wenwu; Chen, Yao

2018-03-01

It is a great challenging task to complete an automatic search of objects underwater. Usually the forward looking sonar is used to find the target, and then the initial identification of the target is completed by the side-scan sonar, and finally the confirmation of the target is accomplished by underwater TV. This paper presents an efficient method for automatic extraction of man-made sensitive targets in underwater TV. Firstly, the image of underwater TV is simplified with taking full advantage of the prior knowledge of the target and the background; then template matching technology is used for target detection; finally the target is confirmed by extracting parallel lines on the target contour. The algorithm is formulated for real-time execution on limited-memory commercial-of-the-shelf platforms and is capable of detection objects in underwater TV.

Design of Autonomous Underwater Vehicle

Directory of Open Access Journals (Sweden)

Tadahiro Hyakudome

2011-03-01

Full Text Available There are concerns about the impact that global warming will have on our environment, and which will inevitably result in expanding deserts and rising water levels. While a lot of underwater vehicles are utilized, AUVs (Autonomous Underwater Vehicle were considered and chosen, as the most suitable tool for conduction survey concerning these global environmental problems. AUVs can comprehensive survey because the vehicle does not have to be connected to the support vessel by tether cable. When such underwater vehicles are made, it is necessary to consider about the following things. 1 Seawater and Water Pressure Environment, 2 Sink, 3 There are no Gas or Battery Charge Stations, 4 Global Positioning System cannot use, 5 Radio waves cannot use. In the paper, outline of above and how deal about it are explained.

Underwater colorectal EMR: remodeling endoscopic mucosal resection.

Science.gov (United States)

Curcio, Gabriele; Granata, Antonino; Ligresti, Dario; Tarantino, Ilaria; Barresi, Luca; Liotta, Rosa; Traina, Mario

2015-05-01

Underwater EMR (UEMR) has been reported as a new technique for the removal of large sessile colorectal polyps without need for submucosal injection. To evaluate (1) outcomes of UEMR, (2) whether UEMR can be easily performed by an endoscopist skilled in traditional EMR without specific dedicated training in UEMR, and (3) whether EUS is required before UEMR. Prospective, observational study. Single, tertiary-care referral center. Underwater EMR. Complete resection and adverse events. A total of 72 consecutive patients underwent UEMR of 81 sessile colorectal polyps. EUS was performed before UEMR in 9 cases (11.1%) with a suspicious mucosal/vascular pattern. The mean polyp size was 18.7 mm (range 10-50 mm); the mean UEMR time was 11.8 minutes. Fifty-five polyps (68%) were removed en bloc, and 26 (32%) were removed with a piecemeal technique. Histopathology consisted of tubular adenomas (25.9%), tubulovillous adenomas (5%), adenomas with high-grade dysplasia (42%), serrated polyps (4.9%), carcinoma in situ (13.6%), and hyperplastic polyps (8.6%). Surveillance colonoscopy was scheduled at 3 months. Complete resection was successful in all patients. No adverse events or recurrence was recorded in any of the patients. Limited follow-up; single-center, uncontrolled study. Interventional endoscopists skilled in conventional EMR performed UEMR without specific dedicated training. EUS may not be required for lesions with no invasive features on high-definition narrow-band imaging. UEMR appears to be an effective and safe alternative to traditional EMR and could eventually improve the way in which we can effectively and safely treat colorectal lesions. Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Identification of nuclear weapons

Science.gov (United States)

Mihalczo, J.T.; King, W.T.

1987-04-10

A method and apparatus for non-invasively indentifying different types of nuclear weapons is disclosed. A neutron generator is placed against the weapon to generate a stream of neutrons causing fissioning within the weapon. A first detects the generation of the neutrons and produces a signal indicative thereof. A second particle detector located on the opposite side of the weapon detects the fission particles and produces signals indicative thereof. The signals are converted into a detected pattern and a computer compares the detected pattern with known patterns of weapons and indicates which known weapon has a substantially similar pattern. Either a time distribution pattern or noise analysis pattern, or both, is used. Gamma-neutron discrimination and a third particle detector for fission particles adjacent the second particle detector are preferably used. The neutrons are generated by either a decay neutron source or a pulled neutron particle accelerator.

Bibliography, subject index, and author index of the literature examined by the Radiation Shielding Information Center (Reactor and Weapons Radiation Shielding). [1973--1976

Energy Technology Data Exchange (ETDEWEB)

1978-01-01

An indexed bibliography is presented of literature selected by the Radiation Shielding Information Center since the previous volume was published in 1974 in the area of radiation transport and shielding against radiation from nuclear reactors, x-ray machines, radioisotopes, nuclear weapons (including fallout), and low-energy accelerators (e.g., neutron generators). In addition to lists of literature titles by subject categories (accessions 3501-4950), author and keyword indexes are given. Most of the literature selected for Vol. V was published in the years 1973 to 1976.

Security with nuclear weapons

International Nuclear Information System (INIS)

Karp, R.C.

1991-01-01

Recent improvements in East-West relations and the process of dramatic political change in Europe may result in unprecedented opportunities to reduce the global arsenal of nuclear weapons. Despite these welcome developments, the prospects for effectively controlling the spread of nuclear capability in the Third World have remained much less encouraging. The possibility of large reductions in nuclear weapons poses fundamental questions about their purpose. Why have some states chosen to acquire nuclear weapons? How and why have these decisions been maintained over time? Why have some states elected to approach, but not cross, the nuclear threshold? This book examines the commonalities and differences in political approaches to nuclear weapons both within and between three groups of states: nuclear, non-nuclear and threshold. The chapters explore the evolution of thinking about nuclear weapons and the role these weapons play in national security planning, and question the official security rationales offered by the nuclear weapon states for the maintenance of nuclear capabilities. For the non-nuclear weapon states, the book presents an analysis of alternative ways of assuring security and foreign policy effectiveness. For the threshold states, it examines the regional contexts within which these states maintain their threshold status. This book transcends traditional East-West approaches to analysis of nuclear issues by giving equal prominence to the issues of nuclear proliferation and non-nuclearism. The book also provides a comprehensive analysis of how current approaches to nuclear weapons have evolved both within and among the groups of countries under study

Remote Underwater Characterization System - Innovative Technology Summary Report

International Nuclear Information System (INIS)

Willis, Walter David

1999-01-01

Characterization and inspection of water-cooled and moderated nuclear reactors and fuel storage pools requires equipment capable of operating underwater. Similarly, the deactivation and decommissioning of older nuclear facilities often requires the facility owner to accurately characterize underwater structures and equipment which may have been sitting idle for years. The underwater characterization equipment is often required to operate at depths exceeding 20 ft (6.1 m) and in relatively confined or congested spaces. The typical baseline approach has been the use of radiation detectors and underwater cameras mounted on long poles, or stationary cameras with pan and tilt features mounted on the sides of the underwater facility. There is a perceived need for an inexpensive, more mobile method of performing close-up inspection and radiation measurements in confined spaces underwater. The Remote Underwater Characterization System (RUCS) is a small, remotely operated submersible vehicle intended to serve multiple purposes in underwater nuclear operations. It is based on the commercially-available ''Scallop'' vehicle, but has been modified by Department of Energy's Robotics Technology Development Program to add auto-depth control, and vehicle orientation and depth monitoring at the operator control panel. The RUCS is designed to provide visual and gamma radiation characterization, even in confined or limited access areas. It was demonstrated in August 1998 at Idaho National Engineering and environmental Laboratory (INEEL) as part of the INEEL Large Scale Demonstration and Deployment Project. During the demonstration it was compared in a ''head-to-head'' fashion with the baseline characterization technology. This paper summarizes the results of the demonstration and lessons learned; comparing and contrasting both technologies in the areas of cost, visual characterization, radiological characterization, and overall operations

Nuclear weapons free zones

International Nuclear Information System (INIS)

Stahl, K.

1990-01-01

The article analyses the concept and problems of the two nuclear weapons free zones in Latin America and in the South Pacific established by the Treaty of Tlatelolco and the Treaty of Rarotonga. So far the nuclear weapons states except China have refused to sign the additional protocols of the Treaties or have signed them only with considerable provisos. Therefore they don't fully recognize the nuclear weapons free status of those zones, or they don't recognize it at all. Both Treaties contain no provisions to regulate the transit of nuclear weapons through the zones. This allows de facto the stationing of nuclear weapons in the military bases of the US which are located within the nuclear weapons free zone of Latin America. The Treaty of Tlatelolco contains also the right of the states, party to the Treaty, to explode nuclear devices for peaceful purposes. Since peaceful and military nuclear explosions cannot be distinguished technically, this right could also undermine the nuclear weapons free status of the region. Important nuclear threshold countries like Argentina and Brazil have furthermore refrained from putting the Treaty into force. (orig.) [de

Chemical Weapons Convention

National Research Council Canada - National Science Library

1997-01-01

On April 29, 1997, the Convention on the Prohibition of the Development, Production, Stockpiling, and Use of Chemical Weapons and on Their Destruction, known as the Chemical Weapons Convention (CWC...

An Underwater Image Enhancement Algorithm for Environment Recognition and Robot Navigation

Directory of Open Access Journals (Sweden)

Kun Xie

2018-03-01

Full Text Available There are many tasks that require clear and easily recognizable images in the field of underwater robotics and marine science, such as underwater target detection and identification of robot navigation and obstacle avoidance. However, water turbidity makes the underwater image quality too low to recognize. This paper proposes the use of the dark channel prior model for underwater environment recognition, in which underwater reflection models are used to obtain enhanced images. The proposed approach achieves very good performance and multi-scene robustness by combining the dark channel prior model with the underwater diffuse model. The experimental results are given to show the effectiveness of the dark channel prior model in underwater scenarios.

Underwater fiber-wireless communication with a passive front end

Science.gov (United States)

Xu, Jing; Sun, Bin; Lyu, Weichao; Kong, Meiwei; Sarwar, Rohail; Han, Jun; Zhang, Wei; Deng, Ning

2017-11-01

We propose and experimentally demonstrate a novel concept on underwater fiber-wireless (Fi-Wi) communication system with a fully passive wireless front end. A low-cost step-index (SI) plastic optical fiber (POF) together with a passive collimating lens at the front end composes the underwater Fi-Wi architecture. We have achieved a 1.71-Gb/s transmission at a mean BER of 4.97 × 10-3 (1.30 × 10-3 when using power loading) over a 50-m SI-POF and 2-m underwater wireless channel using orthogonal frequency division multiplexing (OFDM). Although the wireless part is very short, it actually plays a crucial role in practical underwater implementation, especially in deep sea. Compared with the wired solution (e.g. using a 52-m POF cable without the UWOC part), the proposed underwater Fi-Wi scheme can save optical wet-mate connectors that are sophisticated, very expensive and difficult to install in deep ocean. By combining high-capacity robust POF with the mobility and ubiquity of underwater wireless optical communication (UWOC), the proposed underwater Fi-Wi technology will find wide application in ocean exploration.

Delay Tolerance in Underwater Wireless Communications: A Routing Perspective

Directory of Open Access Journals (Sweden)

Safdar Hussain Bouk

2016-01-01

Full Text Available Similar to terrestrial networks, underwater wireless networks (UWNs also aid several critical tasks including coastal surveillance, underwater pollution detection, and other maritime applications. Currently, once underwater sensor nodes are deployed at different levels of the sea, it is nearly impossible or very expensive to reconfigure the hardware, for example, battery. Taking this issue into account, considerable amount of research has been carried out to ensure minimum energy costs and reliable communication between underwater nodes and base stations. As a result, several different network protocols were proposed for UWN, including MAC, PHY, transport, and routing. Recently, a new paradigm was introduced claiming that the intermittent nature of acoustic channel and signal resulted in designing delay tolerant routing schemes for the UWN, known as an underwater delay tolerant network. In this paper, we provide a comprehensive survey of underwater routing protocols with emphasis on the limitations, challenges, and future open issues in the context of delay tolerant network routing.

Antisatellite weapons

International Nuclear Information System (INIS)

Garwin, R.L.; Gottfried, K.; Hafner, D.L.

1984-01-01

The authors take issue with the assessment that the advent of antisatellite weapons implies that the beneficial role of satellites in arms control, confidence building, and conflict resolution has been judged less important than their ability to support actual military operations. They argue that there is still an opportunity to negotiate a militarily significant and verifiable constraint on the growth of antisatellite technology that would be in the security interest of the US and the world as a whole. They base their opinion on an assessment of the roles of the existing military satellites and their vulnerability to antisatellite weapons and the probable impact of antisatellite weapons on various kinds of crisis and conflict. 10 figures, 1 table

3D Laser Scanner for Underwater Manipulation.

Science.gov (United States)

Palomer, Albert; Ridao, Pere; Youakim, Dina; Ribas, David; Forest, Josep; Petillot, Yvan

2018-04-04

Nowadays, research in autonomous underwater manipulation has demonstrated simple applications like picking an object from the sea floor, turning a valve or plugging and unplugging a connector. These are fairly simple tasks compared with those already demonstrated by the mobile robotics community, which include, among others, safe arm motion within areas populated with a priori unknown obstacles or the recognition and location of objects based on their 3D model to grasp them. Kinect-like 3D sensors have contributed significantly to the advance of mobile manipulation providing 3D sensing capabilities in real-time at low cost. Unfortunately, the underwater robotics community is lacking a 3D sensor with similar capabilities to provide rich 3D information of the work space. In this paper, we present a new underwater 3D laser scanner and demonstrate its capabilities for underwater manipulation. In order to use this sensor in conjunction with manipulators, a calibration method to find the relative position between the manipulator and the 3D laser scanner is presented. Then, two different advanced underwater manipulation tasks beyond the state of the art are demonstrated using two different manipulation systems. First, an eight Degrees of Freedom (DoF) fixed-base manipulator system is used to demonstrate arm motion within a work space populated with a priori unknown fixed obstacles. Next, an eight DoF free floating Underwater Vehicle-Manipulator System (UVMS) is used to autonomously grasp an object from the bottom of a water tank.

Is the nuclear weapon taboo? The nuclear weapon is useless and expensive. Let us not leave the nuclear weapon as an inheritance

International Nuclear Information System (INIS)

Gauchet, Nathalie; Norlain, Bernard; Beach, Hugh; Beckett, Margaret; Quiles, Paul; Rocard, Michel; Ramsbotham, David

2012-03-01

Starting with the definition of the word taboo as stated in a dictionary (a topic it would be unbecoming to evoke, under social and moral proprieties), the author of the first article discusses the status of the nuclear weapon, outlining that it is expensive, useless and monstrous. She notices that conventions on chemical weapons seem to be more efficient than the NPT, that, even if the reasons for abolition are known as well as ways to reach it, it seems difficult to actually address this issue. She evokes different voices coming from different countries or international bodies calling for this abolition. She also states that the nuclear weapon is not a deterrent weapon but a weapon of domination, and calls for the mobilisation of the civil society throughout the world. A second article states that the nuclear weapon is useless and expensive, and that we have to get rid of this hazard for the sake of the planet. Former ministers, Prime ministers, and generals consider that we can and must give up nuclear weapons, notably because the strategic context has completely changed since the fall of the Berlin wall, and support the action of Global Zero

Underwater hearing in the great cormorant (Phalacrocorax carbo sinensis)

DEFF Research Database (Denmark)

Hansen, Kirstin Anderson; Larsen, Ole Næsbye; Wahlberg, Magnus

2016-01-01

The underwater hearing threshold of a great cormorant (Phalacrocroax carbo sinensis) was measured at 2 kHz using psychophysical methods. Previous in-air and underwater testing suggests that cormorants have rather poor in-air hearing compared to other birds of similar size (Johansen, 2016). Prelim......The underwater hearing threshold of a great cormorant (Phalacrocroax carbo sinensis) was measured at 2 kHz using psychophysical methods. Previous in-air and underwater testing suggests that cormorants have rather poor in-air hearing compared to other birds of similar size (Johansen, 2016...

Intelligent Navigation for a Solar Powered Unmanned Underwater Vehicle

Directory of Open Access Journals (Sweden)

Francisco García-Córdova

2013-04-01

Full Text Available In this paper, an intelligent navigation system for an unmanned underwater vehicle powered by renewable energy and designed for shadow water inspection in missions of a long duration is proposed. The system is composed of an underwater vehicle, which tows a surface vehicle. The surface vehicle is a small boat with photovoltaic panels, a methanol fuel cell and communication equipment, which provides energy and communication to the underwater vehicle. The underwater vehicle has sensors to monitor the underwater environment such as sidescan sonar and a video camera in a flexible configuration and sensors to measure the physical and chemical parameters of water quality on predefined paths for long distances. The underwater vehicle implements a biologically inspired neural architecture for autonomous intelligent navigation. Navigation is carried out by integrating a kinematic adaptive neuro-controller for trajectory tracking and an obstacle avoidance adaptive neuro- controller. The autonomous underwater vehicle is capable of operating during long periods of observation and monitoring. This autonomous vehicle is a good tool for observing large areas of sea, since it operates for long periods of time due to the contribution of renewable energy. It correlates all sensor data for time and geodetic position. This vehicle has been used for monitoring the Mar Menor lagoon.

Underwater television camera for monitoring inner side of pressure vessel

International Nuclear Information System (INIS)

Takayama, Kazuhiko.

1997-01-01

An underwater television support device equipped with a rotatable and vertically movable underwater television camera and an underwater television camera controlling device for monitoring images of the inside of the reactor core photographed by the underwater television camera to control the position of the underwater television camera and the underwater light are disposed on an upper lattice plate of a reactor pressure vessel. Both of them are electrically connected with each other by way of a cable to rapidly observe the inside of the reactor core by the underwater television camera. The reproducibility is extremely satisfactory by efficiently concentrating the position of the camera and image information upon inspection and observation. As a result, the steps for periodical inspection can be reduced to shorten the days for the periodical inspection. Since there is no requirement to withdraw fuel assemblies over a wide reactor core region, and the device can be used with the fuel assemblies being left as they are in the reactor, it is suitable for inspection of detectors for nuclear instrumentation. (N.H.)

3D Laser Scanner for Underwater Manipulation

Directory of Open Access Journals (Sweden)

Albert Palomer

2018-04-01

Full Text Available Nowadays, research in autonomous underwater manipulation has demonstrated simple applications like picking an object from the sea floor, turning a valve or plugging and unplugging a connector. These are fairly simple tasks compared with those already demonstrated by the mobile robotics community, which include, among others, safe arm motion within areas populated with a priori unknown obstacles or the recognition and location of objects based on their 3D model to grasp them. Kinect-like 3D sensors have contributed significantly to the advance of mobile manipulation providing 3D sensing capabilities in real-time at low cost. Unfortunately, the underwater robotics community is lacking a 3D sensor with similar capabilities to provide rich 3D information of the work space. In this paper, we present a new underwater 3D laser scanner and demonstrate its capabilities for underwater manipulation. In order to use this sensor in conjunction with manipulators, a calibration method to find the relative position between the manipulator and the 3D laser scanner is presented. Then, two different advanced underwater manipulation tasks beyond the state of the art are demonstrated using two different manipulation systems. First, an eight Degrees of Freedom (DoF fixed-base manipulator system is used to demonstrate arm motion within a work space populated with a priori unknown fixed obstacles. Next, an eight DoF free floating Underwater Vehicle-Manipulator System (UVMS is used to autonomously grasp an object from the bottom of a water tank.

Reconversion of nuclear weapons

CERN Document Server

Kapitza, Sergei P

1992-01-01

The nuclear predicament or nuclear option. Synopsis of three lectures : 1- The physical basis of nuclear technology. Physics of fission. Chain reaction in reactors and weapons. Fission fragments. Separration of isotopes. Radiochemistry.2- Nuclear reactors with slow and fast neutrons. Power, size, fuel and waste. Plutonium production. Dose rate, shielding and health hazard. The lessons of Chernobyl3- Nuclear weapons. Types, energy, blast and fallout. Fusion and hydrogen bombs. What to do with nuclear weapons when you cannot use them? Testing. Nonmilittary use. Can we get rid of the nuclear weapon? Nuclear proliferation. Is there a nuclear future?

Centralised versus Decentralised Control Reconfiguration for Collaborating Underwater Robots

DEFF Research Database (Denmark)

Furno, Lidia; Nielsen, Mikkel Cornelius; Blanke, Mogens

2015-01-01

The present paper introduces an approach to fault-tolerant reconfiguration for collaborating underwater robots. Fault-tolerant reconfiguration is obtained using the virtual actuator approach, Steen (2005). The paper investigates properties of a centralised versus a decentralised implementation an...... an underwater drill needs to be transported and positioned by three collaborating robots as part of an underwater autonomous operation....

Cross Deployment Networking and Systematic Performance Analysis of Underwater Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Zhengxian Wei

2017-07-01

Full Text Available Underwater wireless sensor networks (UWSNs have become a new hot research area. However, due to the work dynamics and harsh ocean environment, how to obtain an UWSN with the best systematic performance while deploying as few sensor nodes as possible and setting up self-adaptive networking is an urgent problem that needs to be solved. Consequently, sensor deployment, networking, and performance calculation of UWSNs are challenging issues, hence the study in this paper centers on this topic and three relevant methods and models are put forward. Firstly, the normal body-centered cubic lattice to cross body-centered cubic lattice (CBCL has been improved, and a deployment process and topology generation method are built. Then most importantly, a cross deployment networking method (CDNM for UWSNs suitable for the underwater environment is proposed. Furthermore, a systematic quar-performance calculation model (SQPCM is proposed from an integrated perspective, in which the systematic performance of a UWSN includes coverage, connectivity, durability and rapid-reactivity. Besides, measurement models are established based on the relationship between systematic performance and influencing parameters. Finally, the influencing parameters are divided into three types, namely, constraint parameters, device performance and networking parameters. Based on these, a networking parameters adjustment method (NPAM for optimized systematic performance of UWSNs has been presented. The simulation results demonstrate that the approach proposed in this paper is feasible and efficient in networking and performance calculation of UWSNs.

Does Britain need nuclear weapons?

International Nuclear Information System (INIS)

Hill, C.R.; Pease, R.S.; Peierls, R.E.; Rotblat, J.

1995-01-01

This report from the British Pugwash Group follows up a detailed international study of the desirability and feasibility of a world free from nuclear weapons with an analysis of issues particular to British nuclear weapons and the associated defense policies. United Kingdom nuclear weapons are reviewed historically, as are the nuclear weapons policies of other countries. A critique of present government policy is presented, with alternative uses for nuclear weapons in the post-Cold war world. The document concludes with a summary of the text and suggests how a British government could move towards global nuclear disarmament. (UK)

Equipment and appliances for underwater operations. Pt. 2

International Nuclear Information System (INIS)

Krueger, P.

1976-01-01

The 6/75 edition of 'mt' reported on the 'ARGE underwater appliances' and the study on 'design development of appliances and equipment for underwater use' in a brief summary. One of these designs, the 'unmanned DSWS underwater appliance' was described in detail. The present article describes three further design developments mentioned in the above study and which are based on unmanned appliances connected to the mother-ship. These designs were developed by Preussag-Meerestechnik. (orig.) [de

The Conference in the Moscow Kremlin State Museums “Historical Weapons in Museums and Private Collections”

Directory of Open Access Journals (Sweden)

Sergey P. Orlenko

2017-03-01

Full Text Available In November 2016 in the Moscow Kremlin State Historical and Cultural Museum and Heritage Site in the framework of events dedicated to the 210th anniversary of the Armoury Chamber museum, an international conference “Historical weapons in museums and private collections”. This scientific forum continued the tradition of conferences held in the Moscow Kremlin Museums in 1999-2007. The participants of this forum discussed a number of priority topics for the studies of the weapon collection history in the Kremlin. These topics were relevant to the national and world studies of weaponology as a whole. In addition to general issues of the history of arms and armour, a number of reports were devoted to the functioning of the historical centers of arms production, weapons collections in Russia and abroad, particular items, as well as the activities of gunsmiths, designers of weapons. The conference was attended by representatives of more than 20 Russian and foreign museums, 14 academic and university research centers and institutions, private collectors and lovers of ancient weapons. During the three days of the conference 36 reports were presented and discussed. Organizers of the conference highlighted a number of reports including new attributions of the items from the Kremlin collections. The conference program is available on the official website of the Moscow Kremlin State Museums. The conference results were published as a collection of proceedings. The weaponology forum in the Kremlin will be held annually. The Moscow Kremlin Museums invite researchers of historical weapons, museum employees and collectors to the active cooperation.

Underwater cladding with laser beam and plasma arc welding

International Nuclear Information System (INIS)

White, R.A.; Fusaro, R.; Jones, M.G.; Solomon, H.D.; Milian-Rodriguez, R.R.

1997-01-01

Two welding processes, plasma arc (transferred arc) (PTA) and laser beam, were investigated to apply cladding to austenitic stainless steels and Inconel 600. These processes have long been used to apply cladding layers , but the novel feature being reported here is that these cladding layers were applied underwater, with a water pressure equivalent to 24 m (80 ft). Being able to apply the cladding underwater is very important for many applications, including the construction of off-shore oil platforms and the repair of nuclear reactors. In the latter case, being able to weld underwater eliminates the need for draining the reactor and removing the fuel. Welding underwater in reactors presents numerous challenges, but the ability to weld without having to drain the reactor and remove the fuel provides a huge cost savings. Welding underwater in reactors must be done remotely, but because of the radioactive corrosion products and neutron activation of the steels, remote welding would also be required even if the reactor is drained and the fuel removed. In fact, without the shielding of the water, the remote welding required if the reactor is drained might be even more difficult than that required with underwater welds. Furthermore, as shall be shown, the underwater welds that the authors have made were of high quality and exhibit compressive rather than tensile residual stresses

Underwater image mosaicking and visual odometry

Science.gov (United States)

Sadjadi, Firooz; Tangirala, Sekhar; Sorber, Scott

2017-05-01

This paper summarizes the results of studies in underwater odometery using a video camera for estimating the velocity of an unmanned underwater vehicle (UUV). Underwater vehicles are usually equipped with sonar and Inertial Measurement Unit (IMU) - an integrated sensor package that combines multiple accelerometers and gyros to produce a three dimensional measurement of both specific force and angular rate with respect to an inertial reference frame for navigation. In this study, we investigate the use of odometry information obtainable from a video camera mounted on a UUV to extract vehicle velocity relative to the ocean floor. A key challenge with this process is the seemingly bland (i.e. featureless) nature of video data obtained underwater which could make conventional approaches to image-based motion estimation difficult. To address this problem, we perform image enhancement, followed by frame to frame image transformation, registration and mosaicking/stitching. With this approach the velocity components associated with the moving sensor (vehicle) are readily obtained from (i) the components of the transform matrix at each frame; (ii) information about the height of the vehicle above the seabed; and (iii) the sensor resolution. Preliminary results are presented.

Underwater Gliders: A Review

Directory of Open Access Journals (Sweden)

Javaid Muhammad Yasar

2014-07-01

Full Text Available Underwater gliders are a type of underwater vehicle that transverse the oceans by shifting its buoyancy, during which its wings develop a component of the downward motion in the horizontal plane, thus producing a forward force. They are primarily used in oceanography sensing and data collection and play an important role in ocean research and development. Although there have been considerable developments in these gliders since the development of the first glider concept in 1989, to date, no review of these gliders have been done. This paper reviews existing underwater gliders, with emphasis on their respective working principles, range and payload capacity. All information on gliders available in the public domain or published in literature from the year 2000-2013 was reviewed. The majority of these gliders have an operational depth of 1000 m and a payload of less than 25 kg. The exception is a blend-body shape glider, which has a payload of approximately 800 kg and an operational depth around about 300 m. However, the commercialization of these gliders has been limited with only three know examples that have been successfully commercialized.

Underwater Object Segmentation Based on Optical Features

Directory of Open Access Journals (Sweden)

Zhe Chen

2018-01-01

Full Text Available Underwater optical environments are seriously affected by various optical inputs, such as artificial light, sky light, and ambient scattered light. The latter two can block underwater object segmentation tasks, since they inhibit the emergence of objects of interest and distort image information, while artificial light can contribute to segmentation. Artificial light often focuses on the object of interest, and, therefore, we can initially identify the region of target objects if the collimation of artificial light is recognized. Based on this concept, we propose an optical feature extraction, calculation, and decision method to identify the collimated region of artificial light as a candidate object region. Then, the second phase employs a level set method to segment the objects of interest within the candidate region. This two-phase structure largely removes background noise and highlights the outline of underwater objects. We test the performance of the method with diverse underwater datasets, demonstrating that it outperforms previous methods.

Chemical and biological weapons

International Nuclear Information System (INIS)

Harris, E.D.

1991-01-01

This paper discusses the prospects of the multilateral negotiations aimed at achieving a complete and total ban on chemical weapons the Chemical Weapons convention (CWC). The control of the proliferation of chemical weapons is no longer just on East-West issue; it is also an issue of concern in Third World Countries, and in some of the wealthier middle eastern nations, such as Kuwait

The US nuclear weapon infrastructure and a stable global nuclear weapon regime

Energy Technology Data Exchange (ETDEWEB)

Immele, John D [Los Alamos National Laboratory; Wagner, Richard L [Los Alamos National Laboratory

2009-01-01

US nuclear weapons capabilities -- extant force structure and nuclear weapons infrastructure as well as declared policy -- influence other nations' nuclear weapons postures, at least to some extent. This influence can be desirable or undesirable, and is, of course, a mixture of both. How strong the influence is, and its nature, are complicated, controversial, and -- in our view -- not well understood but often overstated. Divergent views about this influence and how it might shape the future global nuclear weapons regime seem to us to be the most serious impediment to reaching a national consensus on US weapons policy, force structure and supporting infrastructure. We believe that a paradigm shift to capability-based deterrence and dissuasion is not only consistent with the realities of the world and how it has changed, but also a desirable way for nuclear weapon postures and infrastructures to evolve. The US and other nuclear states could not get to zero nor even reduce nuclear arms and the nuclear profile much further without learning to manage latent capability. This paper has defined three principles for designing NW infrastructure both at the 'next plateau' and 'near zero.' The US can be a leader in reducing weapons and infrastructure and in creating an international regime in which capability gradually substitutes for weapons in being and is transparent. The current 'strategy' of not having policy or a Congressionally-approved plan for transforming the weapons complex is not leadership. If we can conform the US infrastructure to the next plateau and architect it in such a way that it is aligned with further arms reductions, it will have these benefits: The extant stockpile can be reduced in size, while the smaller stockpile still deters attack on the US and Allies. The capabilities of the infrastructure will dissuade emergence of new challenges/threats; if they emerge, nevertheless, the US will be able to deal with them in

Nuclear weapons complex

International Nuclear Information System (INIS)

Rezendes, V.S.

1992-04-01

In addition to long-standing safety and environmental problems plaguing the nuclear weapons complex, this paper reports that the Department of Energy (DOE) faces a major new challenge-how to reconfigure the weapons complex to meet the nation's defense needs in the 21st century. Key decisions still need to be made about the size of the complex; where, if necessary, to relocate various operations; what technologies to use for new tritium production; and what to do with excess weapons-grade material. The choices confronting DOE and Congress are difficult given the conflicting demands for limited resources

Hydrodynamic Coefficients Identification and Experimental Investigation for an Underwater Vehicle

Directory of Open Access Journals (Sweden)

Shaorong XIE

2014-02-01

Full Text Available Hydrodynamic coefficients are the foundation of unmanned underwater vehicles modeling and controller design. In order to reduce identification complexity and acquire necessary hydrodynamic coefficients for controllers design, the motion of the unmanned underwater vehicle was separated into vertical motion and horizontal motion models. Hydrodynamic coefficients were regarded as mapping parameters from input forces and moments to output velocities and acceleration of the unmanned underwater vehicle. The motion models of the unmanned underwater vehicle were nonlinear and Genetic Algorithm was adopted to identify those hydrodynamic coefficients. To verify the identification quality, velocities and acceleration of the unmanned underwater vehicle was measured using inertial sensor under the same conditions as Genetic Algorithm identification. Curves similarity between measured velocities and acceleration and those identified by Genetic Algorithm were used as optimizing standard. It is found that the curves similarity were high and identified hydrodynamic coefficients of the unmanned underwater vehicle satisfied the measured motion states well.

4th Pacific Rim Underwater Acoustics Conference

CERN Document Server

Xu, Wen; Cheng, Qianliu; Zhao, Hangfang

2016-01-01

These proceedings are a collection of 16 selected scientific papers and reviews by distinguished international experts that were presented at the 4th Pacific Rim Underwater Acoustics Conference (PRUAC), held in Hangzhou, China in October 2013. The topics discussed at the conference include internal wave observation and prediction; environmental uncertainty and coupling to sound propagation; environmental noise and ocean dynamics; dynamic modeling in acoustic fields; acoustic tomography and ocean parameter estimation; time reversal and matched field processing; underwater acoustic localization and communication as well as measurement instrumentations and platforms. These proceedings provide insights into the latest developments in underwater acoustics, promoting the exchange of ideas for the benefit of future research.

Defense Special Weapons Agency Advisory Panel on the Nuclear Weapon Effects Program

National Research Council Canada - National Science Library

1998-01-01

We performed the audit in response to allegations made to the Defense Hotline concerning conflicts of interest among members of the Defense Special Weapons Agency Advisory Panel on the Nuclear Weapon Effects Program...

Verifying a nuclear weapon`s response to radiation environments

Energy Technology Data Exchange (ETDEWEB)

Dean, F.F.; Barrett, W.H.

1998-05-01

The process described in the paper is being applied as part of the design verification of a replacement component designed for a nuclear weapon currently in the active stockpile. This process is an adaptation of the process successfully used in nuclear weapon development programs. The verification process concentrates on evaluating system response to radiation environments, verifying system performance during and after exposure to radiation environments, and assessing system survivability.

The influence of underwater turbulence on optical phase measurements

Science.gov (United States)

Redding, Brandon; Davis, Allen; Kirkendall, Clay; Dandridge, Anthony

2016-05-01

Emerging underwater optical imaging and sensing applications rely on phase-sensitive detection to provide added functionality and improved sensitivity. However, underwater turbulence introduces spatio-temporal variations in the refractive index of water which can degrade the performance of these systems. Although the influence of turbulence on traditional, non-interferometric imaging has been investigated, its influence on the optical phase remains poorly understood. Nonetheless, a thorough understanding of the spatio-temporal dynamics of the optical phase of light passing through underwater turbulence are crucial to the design of phase-sensitive imaging and sensing systems. To address this concern, we combined underwater imaging with high speed holography to provide a calibrated characterization of the effects of turbulence on the optical phase. By measuring the modulation transfer function of an underwater imaging system, we were able to calibrate varying levels of optical turbulence intensity using the Simple Underwater Imaging Model (SUIM). We then used high speed holography to measure the temporal dynamics of the optical phase of light passing through varying levels of turbulence. Using this method, we measured the variance in the amplitude and phase of the beam, the temporal correlation of the optical phase, and recorded the turbulence induced phase noise as a function of frequency. By bench marking the effects of varying levels of turbulence on the optical phase, this work provides a basis to evaluate the real-world potential of emerging underwater interferometric sensing modalities.

Optimal Node Placement in Underwater Wireless Sensor Networks

KAUST Repository

Felamban, M.; Shihada, Basem; Jamshaid, K.

2013-01-01

Wireless Sensor Networks (WSN) are expected to play a vital role in the exploration and monitoring of underwater areas which are not easily reachable by humans. However, underwater communication via acoustic waves is subject to several performance

Operational experience in underwater photogrammetry

Science.gov (United States)

Leatherdale, John D.; John Turner, D.

Underwater photogrammetry has become established as a cost-effective technique for inspection and maintenance of platforms and pipelines for the offshore oil industry. A commercial service based in Scotland operates in the North Sea, USA, Brazil, West Africa and Australia. 70 mm cameras and flash units are built for the purpose and analytical plotters and computer graphics systems are used for photogrammetric measurement and analysis of damage, corrosion, weld failures and redesign of underwater structures. Users are seeking simple, low-cost systems for photogrammetric analysis which their engineers can use themselves.

Evaluating the SCC resistance of underwater welds in sodium tetrathionate

International Nuclear Information System (INIS)

White, R.A.; Angeliu, T.M.

1997-01-01

The susceptibility of welds to stress corrosion cracking (SCC) is enhanced by the surface residual tensile stresses generated by the typical welding process. However, underwater plasma transferred arc (PTA) welding has been shown to produce compressive surface residual stresses, an encouraging result if repairs of cracked boiling water reactor (BWR) components are to be made without further endangering them to SCC. This program was designed to verify that underwater PTA welds are resistant to SCC and to determine if underwater PTA welding could mitigate SCC in potentially susceptible welds. This was achieved by exposing various welds on solution annealed (SA) and SA + thermally sensitized 304 stainless steel at 25 C in a solution of 1.5 gm/liter of sodium sulfide added to 0.05M sodium tetrathionate, titrated to a pH of 1.25 with H 2 SO 4 . The autogeneous welds were produced using gas tungsten arc (GTA) and plasma transferred arc (PTA) welding under atmospheric conditions, and PTA welding underwater. After 1 hour of sodium tetrathionate exposure, GTA and air PTA welds exhibited SCC while the underwater PTA weld heat affected zones were more resistant. Underwater PTA welds bisecting a GTA weld eliminated the cracking in the GTA weld heat affected zone under certain conditions. The lack of IG cracking in the region influenced by the underwater PTA weld is consistent with the measurement of compressive surface residual stresses inherent to the underwater welding process

Trade-off Analysis of Underwater Acoustic Sensor Networks

Science.gov (United States)

Tuna, G.; Das, R.

2017-09-01

In the last couple of decades, Underwater Acoustic Sensor Networks (UASNs) were started to be used for various commercial and non-commercial purposes. However, in underwater environments, there are some specific inherent constraints, such as high bit error rate, variable and large propagation delay, limited bandwidth capacity, and short-range communications, which severely degrade the performance of UASNs and limit the lifetime of underwater sensor nodes as well. Therefore, proving reliability of UASN applications poses a challenge. In this study, we try to balance energy consumption of underwater acoustic sensor networks and minimize end-to-end delay using an efficient node placement strategy. Our simulation results reveal that if the number of hops is reduced, energy consumption can be reduced. However, this increases end-to-end delay. Hence, application-specific requirements must be taken into consideration when determining a strategy for node deployment.

The morality of weapons research.

Science.gov (United States)

Forge, John

2004-07-01

I ask whether weapons research is ever justified. Weapons research is identified as the business of the engineer. It is argued that the engineer has responsibility for the uses to which the tools that he designs can be put, and that responsibility extends to the use of weapons. It is maintained that there are no inherently defensive weapons, and hence there is no such thing as 'defensive' weapons research. The issue then is what responsibilities as a professional the engineer has in regard to such research. An account is given to ground the injunction not to provide the means to harm as a duty for the engineers. This account is not, however, absolutist, and as such it allows justifiable exceptions. The answer to my question is thus not that weapons research is never justified but there must be a strong assurance that the results will only be used as a just means in a just cause.

Application of Underwater Shock Wave Focusing to the Development of Extracorporeal Shock Wave Lithotripsy

Science.gov (United States)

Takayama, Kazuyoshi

1993-05-01

This paper describes a summary of a research project for the development of extracorporeal shock wave lithotripsy (ESWL), which has been carried out, under close collaboration between the Shock Wave Research Center of Tohoku University and the School of Medicine, Tohoku University. The ESWL is a noninvasive clinical treatment of disintegrating human calculi and one of the most peaceful applications of shock waves. Underwater spherical shock waves were generated by explosion of microexplosives. Characteristics of the underwater shock waves and of ultrasound focusing were studied by means of holographic interferometric flow visualization and polyvinyliden-difluoride (PVDF) pressure transducers. These focused pressures, when applied to clinical treatments, could effectively and noninvasively disintegrate urinary tract stones or gallbladder stones. However, despite clincal success, tissue damage occurs during ESWL treatments, and the possible mechanism of tissue damage is briefly described.

Making weapons, talking peace

International Nuclear Information System (INIS)

York, H.F.

1987-01-01

The memoirs of the author traces his life from his first-year graduate studies in physics at the University of Rochester in 1942 to his present position as Director of the University of California's Institute on Global Conflict and Cooperation. The part of his life involved in making weapons extends from 1942 to 1961. During this period, he worked with E.O. Lawrence on the Manhattan Project and served as director of Livermore after it became the Atomic Energy Commission's second nuclear weapons laboratory. He also served on many government advisory boards and commissions dealing with nuclear and other weapons. In 1961, the combination of a heart attack and changes in administration in Washington led York too return to the University of California for the talking peace portion of his life. He has since become a public exponent of arms control and disarmament and the futility of seeking increased security through more and better nuclear weapons. York's explanation of his move from making weapons to talking peace leaves the reader with a puzzle

Do Weapons Facilitate Adolescent Delinquency? An Examination of Weapon Carrying and Delinquency Among Adolescents.

Science.gov (United States)

Emmert, Amanda D; Hall, Gina Penly; Lizotte, Alan J

2018-03-01

This article examines whether weapon carrying influences the frequency and variety of violent, property, and drug delinquency adolescents commit through fixed-effects analyses of data from the Rochester Youth Development Study (RYDS). We conclude that weapon carrying contributes to violent, substance, and property delinquency, and delinquent behaviors learned during weapon carrying continue to affect substance and property delinquency long after carrying has ceased.

Prerequisites for a nuclear weapons convention

International Nuclear Information System (INIS)

Liebert, W.

1999-01-01

A Nuclear Weapons Convention (NWC) would prohibit the research, development, production, testing, stockpiling, transfer, use and threat of use of nuclear weapons and would serve their total elimination.' In this fashion it follows the model laid out by the biological and chemical weapons conventions. The NWC would encompass a few other treaties and while replacing them should learn from their experiences. The Nuclear Weapons Convention should at some given point in the future replace the Non-Proliferation Treaty (NPT) and so resolve its contradictions and shortcomings. The main objectives of an NWC Would be: reduction of the nuclear arsenals of the 'five' nuclear weapons powers down to zero within a set of fixed periods of time; elimination of stockpiles of weapons-usable materials and, where existent, nuclear warheads in de-facto nuclear weapon and threshold states; providing assurance that all states will retain their non-nuclear status forever

Filming Underwater in 3d Respecting Stereographic Rules

Science.gov (United States)

Rinaldi, R.; Hordosch, H.

2015-04-01

After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie's box offices due to the overall quality of its products. Special environments such as space ("Gravity") and the underwater realm look perfect to be reproduced in 3D. "Filming in space" was possible in "Gravity" using special effects and computer graphic. The underwater realm is still difficult to be handled. Underwater filming in 3D was not that easy and effective as filming in 2D, since not long ago. After almost 3 years of research, a French, Austrian and Italian team realized a perfect tool to film underwater, in 3D, without any constrains. This allows filmmakers to bring the audience deep inside an environment where they most probably will never have the chance to be.

FILMING UNDERWATER IN 3D RESPECTING STEREOGRAPHIC RULES

Directory of Open Access Journals (Sweden)

R. Rinaldi

2015-04-01

Full Text Available After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space ("Gravity" and the underwater realm look perfect to be reproduced in 3D. "Filming in space" was possible in "Gravity" using special effects and computer graphic. The underwater realm is still difficult to be handled. Underwater filming in 3D was not that easy and effective as filming in 2D, since not long ago. After almost 3 years of research, a French, Austrian and Italian team realized a perfect tool to film underwater, in 3D, without any constrains. This allows filmmakers to bring the audience deep inside an environment where they most probably will never have the chance to be.

Wireless Underwater Monitoring Systems Based on Energy Harvestings

Directory of Open Access Journals (Sweden)

Sea-Hee HWANGBO

2013-01-01

Full Text Available One of the important research fields for aquatic exploitation and conservation is underwater wireless sensor network. Since limited energy source for underwater nodes and devices is a main open problem, in this paper, we propose wireless underwater monitoring systems powered by energy harvester which resolves the energy constraint. The target system generates renewable energy from energy harvester and shares the energy with underwater sensor nodes. For the realization of the system, key components to be investigated are discriminated as follows: acoustic modem, actuator, smart battery charge controller, energy harvester and wireless power transfer module. By developing acoustic modem, actuator and smart battery charge controller and utilizing off-the-shelf energy harvester and wireless power transfer module, we design and implement a prototype of the system. Also, we verify the feasibility of concept of target system by conducting indoor and outdoor experiments.

Low-contrast underwater living fish recognition using PCANet

Science.gov (United States)

Sun, Xin; Yang, Jianping; Wang, Changgang; Dong, Junyu; Wang, Xinhua

2018-04-01

Quantitative and statistical analysis of ocean creatures is critical to ecological and environmental studies. And living fish recognition is one of the most essential requirements for fishery industry. However, light attenuation and scattering phenomenon are present in the underwater environment, which makes underwater images low-contrast and blurry. This paper tries to design a robust framework for accurate fish recognition. The framework introduces a two stage PCA Network to extract abstract features from fish images. On a real-world fish recognition dataset, we use a linear SVM classifier and set penalty coefficients to conquer data unbalanced issue. Feature visualization results show that our method can avoid the feature distortion in boundary regions of underwater image. Experiments results show that the PCA Network can extract discriminate features and achieve promising recognition accuracy. The framework improves the recognition accuracy of underwater living fishes and can be easily applied to marine fishery industry.

Automatic stabilization of underwater robots in the time manipulation operations

International Nuclear Information System (INIS)

Filaretov, V.F.; Koval, E.V.

1994-01-01

When carrying out underwater technical works by means of an underwater vehicles having a manipulator it is desirable to perform manipulation operations in the regime of the underwater vehicle hovering above the object without durable and complicated operations up its rigid fixation. Underwater vehicle stabilization is achieved by compensation all the effects on the vehicle caused by the operating manipulator in water medium. This automatic stabilization is formed due to input of the required control signals into corresponding vehicle propellers proportional to calculated components of the generalized forces and moments. The propellers should form stops reacting against effects

Weapons and hope

International Nuclear Information System (INIS)

Dyson, F.

1984-01-01

The British-born physicist presents a full-blown critique of US weapons policy. His careful evaluation of opposing views leads him to endorse a live-and-let-live concept of arms control, which would reject both assured destruction and first use of nuclear weapons in favor of abolishing them. Dyson's faith in the humane progress of military technology and his tolerance of dangerous conventional weapons will not please dovish readers, while his denunciation of military idolatry and his support of a nuclear freeze will disappoint some hawks. Along with moving personal memories of war and pacifism, the most original sections of the book are the author's insightful comments about the Soviet Union and the issue of verification

Chinese strategic weapons and the plutonium option (U)

Energy Technology Data Exchange (ETDEWEB)

Lewis, John W.; Xui Litai

1988-04-01

In their article "Chinese Strategic Weapons and the Plutonium Option," John W. Lewis and Xue Litai of the Center for International Security and Arms Control at Stanford University's International Strategic Institute present an unclassified look at plutonium processing in the PRC. The article draws heavily on unclassified PRC sources for its short look at this important subject. Interested readers will find more detailed information in the recently available works referenced in the article.

Extended Nuclear Deterrence for Europe Without Forward-based Weapons

Science.gov (United States)

2012-02-15

financial costs of nuclear burden sharing, bolsters safety and security and further reduces proliferation risks. 22 Bibliography Bildt, Carl and... Sagan , Scott D. and Waltz, Kenneth N. The Spread of Nuclear Weapons: A Debate Renewed. W. W. Norton and Company New York, NY and London...Point. Center for International Relations, Reports and Analyses. Konrad-Adenauer Foundation, Warsaw, 2011, 2. 30 Bildt, Carl and Sikorski, Radek

WODA technical guidance on underwater sound from dredging

NARCIS (Netherlands)

Thomsen, F.; Borsani, F.; Clarke, D.; Jong, C. de; Wit, P. de; Goethals, F.; Holtkamp, M.; Martin, E.S.; Spadaro, P.; Raalte, G. van; Victor, G.Y.V.; Jensen, A.

2016-01-01

The World Organization of Dredging Associations (WODA) has identified underwater sound as an environmental issue that needs further consideration. A WODA Expert Group on Underwater Sound (WEGUS) prepared a guidance paper in 2013 on dredging sound, including a summary of potential impacts on aquatic

Underwater laser imaging system (UWLIS)

Energy Technology Data Exchange (ETDEWEB)

DeLong, M. [Lawrence Livermore National Lab., CA (United States)

1994-11-15

Practical limitations with underwater imaging systems area reached when the noise in the back scattered radiation generated in the water between the imaging system and the target obscures the spatial contrast and resolution necessary for target discovery and identification. The advent of high power lasers operating in the blue-green portion of the visible spectrum (oceanic transmission window) has led to improved experimental illumination systems for underwater imaging. Range-gated and synchronously scanned devices take advantage of the unique temporal and spatial coherence properties of laser radiation, respectively, to overcome the deleterious effects of common volume back scatter.

Maintaining non-nuclear weapon status

International Nuclear Information System (INIS)

Muller, H.

1991-01-01

Among the some 170 sovereign states in the world, five are legally recognized as nuclear weapon states (NWS) under the terms of the 1968 Non-Proliferation Treaty (NPT). Six countries (Argentina, Brazil, India, Israel, Pakistan, and South Africa) are counted as threshold states: they possess sizeable unsafeguarded nuclear facilities or have passed the brink of a nuclear test or of clandestine weapon production. Six other countries (Iran, Iraq, Libya, Taiwan, and North and South Korea) have been suspected periodically of either considering the nuclear weapon option or of working secretly on the development of weapons. Thus, about 150 non-nuclear weapon states (NNWS) remain which neither possess nuclear weapons nor strive to acquire them. These states are distributed throughout the globe and encompass highly industrialized as well as underdeveloped countries, liberal democracies, socialist states, sheikdoms and dictatorships. Some NNWS face acute military threats; other are far removed from the quarrels of the world, as in the case of some remote fortunate islands. Furthermore, NNWS may be members of nuclear-umbrella alliances or may have opted for a policy of neutrality or non-alignment

The return of nuclear weapons

International Nuclear Information System (INIS)

Calvez, Jean-Yves

2005-01-01

Written after the 2005 NPT review conference, this article first recalls the early stages of nuclear proliferation: acquisition of nuclear weapons by Great-Britain, USSR, France and China, and creation of the NPT in 1970. The author briefly evokes some weaknesses and violations of this treaty: emergence of new nuclear powers (India, Pakistan, Israel) and of nuclear weapon programmes (Iran, North Korea). He outlines the lack of true rules to impede countries to develop nuclear weapons, and then states that the only solution seems to be a simple abolition of these weapons. This option is notably supported by the Catholic Church as outlined and recalled here. The author discusses the situation of this abolition option, and notices that, even though NPT members committed themselves on this way, some also decided to develop new and smaller weapons. Then, it becomes always more difficult to persuade countries not to possess these weapons. The author finally discusses the issues of terrorism threat in relationship to the miniaturisation process, and regrets the lack of commitment in an abolition process

Construction Method of the Topographical Features Model for Underwater Terrain Navigation

Directory of Open Access Journals (Sweden)

Wang Lihui

2015-09-01

Full Text Available Terrain database is the reference basic for autonomous underwater vehicle (AUV to implement underwater terrain navigation (UTN functions, and is the important part of building topographical features model for UTN. To investigate the feasibility and correlation of a variety of terrain parameters as terrain navigation information metrics, this paper described and analyzed the underwater terrain features and topography parameters calculation method. Proposing a comprehensive evaluation method for terrain navigation information, and constructing an underwater navigation information analysis model, which is associated with topographic features. Simulation results show that the underwater terrain features, are associated with UTN information directly or indirectly, also affect the terrain matching capture probability and the positioning accuracy directly.

Wounds and weapons

Energy Technology Data Exchange (ETDEWEB)

Vogel, H. [Asklepios Klinik St. Georg, Roentgenabteilung, Lohmuehlenstrasse 5, 20099 Hamburg (Germany)], E-mail: Hermann.vogel@ak-stgeorg.lbk-hh.de; Dootz, B. [Asklepios Klinik St. Georg, Roentgenabteilung, Lohmuehlenstrasse 5, 20099 Hamburg (Germany)

2007-08-15

Purpose: X-ray findings are described, which are typical for injuries due to conventional weapons. It is intended to demonstrate that radiographs can show findings characteristic for weapons. Material and method: The radiograms have been collected in Vietnam, Croatia, Serbia, Bosnia, Chad, Iran, Afghanistan, USA, Great Britain, France, Israel, Palestine, and Germany. Results: Radiograms of injuries due to hand grenades show their content (globes) and cover fragments. The globes are localized regionally in the victim's body. Survivors of cluster bombs show singular or few globes; having been hit by many globes would have been lethal. Shotguns produce characteristic distributions of the pallets and depth of penetration different from those of hand grenades and cluster bombs; cover fragments are lacking. Gunshot wounds (GSW) can be differentiated in those to low velocity bullets, high velocity projectiles, and projectiles, which disintegrate on impact. The radiogram furnishes the information about a dangerous shock and helps to recognize the weapon. Radiograms of victims of explosion show fragments and injuries due to the blast, information valid for therapy planning and prognosis. The radiogram shows details which can be used in therapy, forensic medicine and in war propaganda - examples could be findings typical for cluster bombs and for dumdum bullets; it shows the cruelty of the employment of weapons against humans and the conflict between the goal of medical care and those of military actions. Conclusion: Radiographs may show, which weapon has been employed; they can be read as war reports.

Wounds and weapons

International Nuclear Information System (INIS)

Vogel, H.; Dootz, B.

2007-01-01

Purpose: X-ray findings are described, which are typical for injuries due to conventional weapons. It is intended to demonstrate that radiographs can show findings characteristic for weapons. Material and method: The radiograms have been collected in Vietnam, Croatia, Serbia, Bosnia, Chad, Iran, Afghanistan, USA, Great Britain, France, Israel, Palestine, and Germany. Results: Radiograms of injuries due to hand grenades show their content (globes) and cover fragments. The globes are localized regionally in the victim's body. Survivors of cluster bombs show singular or few globes; having been hit by many globes would have been lethal. Shotguns produce characteristic distributions of the pallets and depth of penetration different from those of hand grenades and cluster bombs; cover fragments are lacking. Gunshot wounds (GSW) can be differentiated in those to low velocity bullets, high velocity projectiles, and projectiles, which disintegrate on impact. The radiogram furnishes the information about a dangerous shock and helps to recognize the weapon. Radiograms of victims of explosion show fragments and injuries due to the blast, information valid for therapy planning and prognosis. The radiogram shows details which can be used in therapy, forensic medicine and in war propaganda - examples could be findings typical for cluster bombs and for dumdum bullets; it shows the cruelty of the employment of weapons against humans and the conflict between the goal of medical care and those of military actions. Conclusion: Radiographs may show, which weapon has been employed; they can be read as war reports

A PROPOSAL FOR A SUSTAINABLE MODEL BASED UPON UNDERWATER TOURISM RESEARCH IN AYVALIK

Directory of Open Access Journals (Sweden)

A. GÖKDENİZ

2013-03-01

Full Text Available Underwater sports are the activities being done with the aims of witnessing the beauties, hunting, taking photos, the ecology and the archaeology of underwater analysing or finding out the human being’s boundaries by improving the physical and psychological skills of men. The initial aim of this project is to increase the underwater flora and the fauna heritage of Ayvalık and to bring them in tourism. Ayvalık is on the west coast of Turkey. It is getting more and more famous with its underwater richness. Also, to form a new underwater sports centre in order to contribute to the improvement of the region. By providing visual attractiveness, the tourists related to underwater sports will pay attention to Ayvalık and underwater tourism will contribute much to the economy of the region. The aim of this project is to improve the underwater sports which is now a hobby than a sport. In Ayvalık Underwater World study, we dealt with 247 divers and 4 underwater sports club. In this study, we analysed the expectation, satisfaction, demographic and economic level of 247 divers about the services in the region. Interview technique has been used in the study on the 4 underwater sports clubs which are hosting divers. As a conclusion, a report has been prepared in which detailed information and proposals are presented by developing a sustainable marketing model concerned with the underwater sports for those who want to possess information, shareholders of the sector and make analyse about tourism.

Blue-light digital communication in underwater environments utilizing orbital angular momentum

Science.gov (United States)

Baghdady, Joshua; Miller, Keith; Osler, Sean; Morgan, Kaitlyn; Li, Wenzhe; Johnson, Eric; Cochenour, Brandon

2016-05-01

Underwater optical communication has recently become the topic of much investigation as the demands for underwater data transmission have rapidly grown in recent years. The need for reliable, high-speed, secure underwater communication has turned increasingly to blue-light optical solutions. The blue-green visible wavelength window provides an attractive solution to the problem of underwater data transmission thanks to its low attenuation, where traditional RF solutions used in free-space communications collapse. Beginning with GaN laser diodes as the optical source, this work explores the encoding and transmission of digital data across underwater environments of varying turbidities. Given the challenges present in an underwater environment, such as the mechanical and optical turbulences that make proper alignment difficult to maintain, it is desirable to achieve extremely high data rates in order to allow the time window of alignment between the transmitter and receiver to be as small as possible. In this paper, work is done to increase underwater data rates through the use of orbital angular momentum. Results are shown for a range of data rates across a variety of channel types ranging in turbidity from that of a clear ocean to a dirty harbor.

Underwater 3D Surface Measurement Using Fringe Projection Based Scanning Devices.

Science.gov (United States)

Bräuer-Burchardt, Christian; Heinze, Matthias; Schmidt, Ingo; Kühmstedt, Peter; Notni, Gunther

2015-12-23

In this work we show the principle of optical 3D surface measurements based on the fringe projection technique for underwater applications. The challenges of underwater use of this technique are shown and discussed in comparison with the classical application. We describe an extended camera model which takes refraction effects into account as well as a proposal of an effective, low-effort calibration procedure for underwater optical stereo scanners. This calibration technique combines a classical air calibration based on the pinhole model with ray-based modeling and requires only a few underwater recordings of an object of known length and a planar surface. We demonstrate a new underwater 3D scanning device based on the fringe projection technique. It has a weight of about 10 kg and the maximal water depth for application of the scanner is 40 m. It covers an underwater measurement volume of 250 mm × 200 mm × 120 mm. The surface of the measurement objects is captured with a lateral resolution of 150 μm in a third of a second. Calibration evaluation results are presented and examples of first underwater measurements are given.

Single underwater image enhancement based on color cast removal and visibility restoration

Science.gov (United States)

Li, Chongyi; Guo, Jichang; Wang, Bo; Cong, Runmin; Zhang, Yan; Wang, Jian

2016-05-01

Images taken under underwater condition usually have color cast and serious loss of contrast and visibility. Degraded underwater images are inconvenient for observation and analysis. In order to address these problems, an underwater image-enhancement method is proposed. A simple yet effective underwater image color cast removal algorithm is first presented based on the optimization theory. Then, based on the minimum information loss principle and inherent relationship of medium transmission maps of three color channels in an underwater image, an effective visibility restoration algorithm is proposed to recover visibility, contrast, and natural appearance of degraded underwater images. To evaluate the performance of the proposed method, qualitative comparison, quantitative comparison, and color accuracy test are conducted. Experimental results demonstrate that the proposed method can effectively remove color cast, improve contrast and visibility, and recover natural appearance of degraded underwater images. Additionally, the proposed method is comparable to and even better than several state-of-the-art methods.

Study of archaeological underwater finds: deterioration and conservation

Science.gov (United States)

Crisci, G. M.; La Russa, M. F.; Macchione, M.; Malagodi, M.; Palermo, A. M.; Ruffolo, S. A.

2010-09-01

This study is aimed at an assessment of the methodologies, instruments and new applications for underwater archaeology. Research focused on study of the various kinds of degradation affecting underwater finds and stone materials aged in underwater environment, efficiency evaluation of various surface cleaning methods and study and mixing of protective products with consolidating resins and antimicrobial biocides to be applied to restored underwater finds. Transmitted light optical microscopy and scanning electron microscopy (SEM) were used to study surface biofilms and the interactions with samples of different stone materials such as brick, marble and granite immersed in the submarine archaeological area of Crotone (South of Italy). Surface cleaning tests were performed with application of ion exchange resins, EDTA, hydrogen peroxide and ultrasound techniques. Capillary water absorption, simulated solar ageing and colourimetric measurements were carried out to evaluate hydrophobic and consolidant properties; to assess biocidal efficacy, heterotrophic micro-organisms ( Aspergillus niger) were inoculated on agar plates and growth inhibition was measured.

Efficient Weibull channel model for salinity induced turbulent underwater wireless optical communications

KAUST Repository

Oubei, Hassan M.; Zedini, Emna; Elafandy, Rami T.; Kammoun, Abla; Ng, Tien Khee; Alouini, Mohamed-Slim; Ooi, Boon S.

2017-01-01

Recent advances in underwater wireless optical communications necessitate a better understanding of the underwater channel. We propose the Weibull model to characterize the fading of salinity induced turbulent underwater wireless optical channels

Underwater laser cutting of metallic structures

International Nuclear Information System (INIS)

Alfille, J.P.; Schildknecht, J.; Ramaswami, V.S.

1993-01-01

In the frame of an european contract, the feasibility of the underwater cutting with a CO 2 laser power is studied. The aim of this work is the dismantling metallic structures of reactors pools. The paper analyzes the general concept of the experimental device, the underwater cutting head, the experimenting vessel, examples of cuttings in dismantling situation with a 500 W CO 2 laser, and examples of cuttings with a 5 kW CO 2 laser. (author). 2 refs., 9 figs., 2 tabs

Digital sonar design in underwater acoustics principles and applications

CERN Document Server

Li, Qihu

2012-01-01

"Digital Sonar Design in Underwater Acoustics Principles and Applications" provides comprehensive and up-to-date coverage of research on sonar design, including the basic theory and techniques of digital signal processing, basic concept of information theory, ocean acoustics, underwater acoustic signal propagation theory, and underwater signal processing theory. This book discusses the general design procedure and approaches to implementation, the design method, system simulation theory and techniques, sonar tests in the laboratory, lake and sea, and practical validation criteria and methods for digital sonar design. It is intended for researchers in the fields of underwater signal processing and sonar design, and also for navy officers and ocean explorers. Qihu Li is a professor at the Institute of Acoustics, Chinese Academy of Sciences, and an academician of the Chinese Academy of Sciences.

Underwater Coatings Testing for INEEL Fuel Basin Applications

International Nuclear Information System (INIS)

Julia L. Tripp

2004-01-01

The Idaho National Engineering and Environmental Laboratory (INEEL) is deactivating several fuel storage basins. Airborne contamination is a concern when the sides of the basins are exposed and allowed to dry during water removal. One way of controlling this airborne contamination is to fix the contamination in place while the pool walls are still submerged. There are many underwater coatings available on the market that are used in marine, naval and other applications. A series of tests were run to determine whether the candidate underwater fixatives are easily applied and adhere well to the substrates (pool wall materials) found in INEEL fuel pools. The four pools considered included (1) Test Area North (TAN-607) with epoxy painted concrete walls; (2) Idaho Nuclear Technology and Engineering Center (INTEC) (CPP-603) with bare concrete walls; (3) Materials Test Reactor (MTR) Canal with stainless steel lined concrete walls; and (4) Power Burst Facility (PBF-620) with stainless steel lined concrete walls on the bottom and epoxy painted carbon steel lined walls on the upper portions. Therefore, the four materials chosen for testing included bare concrete, epoxy painted concrete, epoxy painted carbon steel, and stainless steel. The typical water temperature of the pools varies from 55 F to 80 F dependent on the pool and the season. These tests were done at room temperature

Underwater Coatings Testing for INEEL Fuel Basin Applications

Energy Technology Data Exchange (ETDEWEB)

Julia L. Tripp

2004-01-01

The Idaho National Engineering and Environmental Laboratory (INEEL) is deactivating several fuel storage basins. Airborne contamination is a concern when the sides of the basins are exposed and allowed to dry during water removal. One way of controlling this airborne contamination is to fix the contamination in place while the pool walls are still submerged. There are many underwater coatings available on the market that are used in marine, naval and other applications. A series of tests were run to determine whether the candidate underwater fixatives are easily applied and adhere well to the substrates (pool wall materials) found in INEEL fuel pools. The four pools considered included (1) Test Area North (TAN-607) with epoxy painted concrete walls; (2) Idaho Nuclear Technology and Engineering Center (INTEC) (CPP-603) with bare concrete walls; (3) Materials Test Reactor (MTR) Canal with stainless steel lined concrete walls; and (4) Power Burst Facility (PBF-620) with stainless steel lined concrete walls on the bottom and epoxy painted carbon steel lined walls on the upper portions. Therefore, the four materials chosen for testing included bare concrete, epoxy painted concrete, epoxy painted carbon steel, and stainless steel. The typical water temperature of the pools varies from 55 F to 80 F dependent on the pool and the season. These tests were done at room temperature.

Vulnerability assessment of a space based weapon platform electronic system exposed to a thermonuclear weapon detonation

Science.gov (United States)

Perez, C. L.; Johnson, J. O.

Rapidly changing world events, the increased number of nations with inter-continental ballistic missile capability, and the proliferation of nuclear weapon technology will increase the number of nuclear threats facing the world today. Monitoring these nation's activities and providing an early warning and/or intercept system via reconnaissance and surveillance satellites and space based weapon platforms is a viable deterrent against a surprise nuclear attack. However, the deployment of satellite and weapon platform assets in space will subject the sensitive electronic equipment to a variety of natural and man-made radiation environments. These include Van Allen Belt protons and electrons; galactic and solar flare protons; and neutrons, gamma rays, and x-rays from intentionally detonated fission and fusion weapons. In this paper, the MASH vl.0 code system is used to estimate the dose to the critical electronics components of an idealized space based weapon platform from neutron and gamma-ray radiation emitted from a thermonuclear weapon detonation in space. Fluence and dose assessments were performed for the platform fully loaded, and in several stages representing limited engagement scenarios. The results indicate vulnerabilities to the Command, Control, and Communication bay instruments from radiation damage for a nuclear weapon detonation for certain source/platform orientations. The distance at which damage occurs will depend on the weapon yield (n,(gamma)/kiloton) and size (kilotons).

Underwater wireless optical communications: From system-level demonstrations to channel modelling

KAUST Repository

Oubei, Hassan M.

2018-01-09

In this paper, we discuss about recent experimental advances in underwater wireless optical communications (UWOC) over various underwater channel water types using different modulation schemes as well as modelling and describing the statistical properties of turbulence-induced fading in underwater wireless optical channels using laser beam intensity fluctuations measurements.

Effectiveness of an Automatic Tracking Software in Underwater Motion Analysis

Directory of Open Access Journals (Sweden)

Fabrício A. Magalhaes

2013-12-01

Full Text Available Tracking of markers placed on anatomical landmarks is a common practice in sports science to perform the kinematic analysis that interests both athletes and coaches. Although different software programs have been developed to automatically track markers and/or features, none of them was specifically designed to analyze underwater motion. Hence, this study aimed to evaluate the effectiveness of a software developed for automatic tracking of underwater movements (DVP, based on the Kanade-Lucas-Tomasi feature tracker. Twenty-one video recordings of different aquatic exercises (n = 2940 markers’ positions were manually tracked to determine the markers’ center coordinates. Then, the videos were automatically tracked using DVP and a commercially available software (COM. Since tracking techniques may produce false targets, an operator was instructed to stop the automatic procedure and to correct the position of the cursor when the distance between the calculated marker’s coordinate and the reference one was higher than 4 pixels. The proportion of manual interventions required by the software was used as a measure of the degree of automation. Overall, manual interventions were 10.4% lower for DVP (7.4% than for COM (17.8%. Moreover, when examining the different exercise modes separately, the percentage of manual interventions was 5.6% to 29.3% lower for DVP than for COM. Similar results were observed when analyzing the type of marker rather than the type of exercise, with 9.9% less manual interventions for DVP than for COM. In conclusion, based on these results, the developed automatic tracking software presented can be used as a valid and useful tool for underwater motion analysis.

WODA Technical Guidance on Underwater Sound from Dredging.

Science.gov (United States)

Thomsen, Frank; Borsani, Fabrizio; Clarke, Douglas; de Jong, Christ; de Wit, Pim; Goethals, Fredrik; Holtkamp, Martine; Martin, Elena San; Spadaro, Philip; van Raalte, Gerard; Victor, George Yesu Vedha; Jensen, Anders

2016-01-01

The World Organization of Dredging Associations (WODA) has identified underwater sound as an environmental issue that needs further consideration. A WODA Expert Group on Underwater Sound (WEGUS) prepared a guidance paper in 2013 on dredging sound, including a summary of potential impacts on aquatic biota and advice on underwater sound monitoring procedures. The paper follows a risk-based approach and provides guidance for standardization of acoustic terminology and methods for data collection and analysis. Furthermore, the literature on dredging-related sounds and the effects of dredging sounds on marine life is surveyed and guidance on the management of dredging-related sound risks is provided.

Communication and cooperation in underwater acoustic networks

Science.gov (United States)

Yerramalli, Srinivas

In this thesis, we present a study of several problems related to underwater point to point communications and network formation. We explore techniques to improve the achievable data rate on a point to point link using better physical layer techniques and then study sensor cooperation which improves the throughput and reliability in an underwater network. Robust point-to-point communications in underwater networks has become increasingly critical in several military and civilian applications related to underwater communications. We present several physical layer signaling and detection techniques tailored to the underwater channel model to improve the reliability of data detection. First, a simplified underwater channel model in which the time scale distortion on each path is assumed to be the same (single scale channel model in contrast to a more general multi scale model). A novel technique, which exploits the nature of OFDM signaling and the time scale distortion, called Partial FFT Demodulation is derived. It is observed that this new technique has some unique interference suppression properties and performs better than traditional equalizers in several scenarios of interest. Next, we consider the multi scale model for the underwater channel and assume that single scale processing is performed at the receiver. We then derive optimized front end pre-processing techniques to reduce the interference caused during single scale processing of signals transmitted on a multi-scale channel. We then propose an improvised channel estimation technique using dictionary optimization methods for compressive sensing and show that significant performance gains can be obtained using this technique. In the next part of this thesis, we consider the problem of sensor node cooperation among rational nodes whose objective is to improve their individual data rates. We first consider the problem of transmitter cooperation in a multiple access channel and investigate the stability of

Dynamics of the congestion control model in underwater wireless sensor networks with time delay

International Nuclear Information System (INIS)

Dong, Tao; Hu, Wenjie; Liao, Xiaofeng

2016-01-01

In this paper, a congestion control model in underwater wireless sensor network with time delay is considered. First, the boundedness of the positive equilibrium, where the samples density is positive for each node and the different event flows coexist, is investigated, which implies that the samples density of sensor node cannot exceed the Environmental carrying capacity. Then, by considering the time delay can be regarded as a bifurcating parameter, the dynamical behaviors, which include local stability and Hopf bifurcation, are investigated. It is found that when the communication time delay passes a critical value, the system loses its stability and a Hopf bifurcation occurs, which means the underwater wireless sensor network will be congested, even collapsed. Furthermore, the direction and stability of the bifurcating periodic solutions are derived by applying the normal form theory and the center manifold theorem. Finally, some numerical examples are finally performed to verify the theoretical results.

Political accountability and autonomous weapons

Directory of Open Access Journals (Sweden)

James Igoe Walsh

2015-09-01

Full Text Available Autonomous weapons would have the capacity to select and attack targets without direct human input. One important objection to the introduction of such weapons is that they will make it more difficult to identify and hold accountable those responsible for undesirable outcomes such as mission failures and civilian casualties. I hypothesize that individuals can modify their attribution of responsibility in predicable ways to accommodate this new technology. The results of a survey experiment are consistent with this; subjects continue to find responsible and hold accountable political and military leaders when autonomous weapons are used, but also attribute responsibility to the designers and programmers of such weapons.

Survivability design for a hybrid underwater vehicle

Energy Technology Data Exchange (ETDEWEB)

Wang, Biao; Wu, Chao; Li, Xiang; Zhao, Qingkai; Ge, Tong [State Key Lab of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

2015-03-10

A novel hybrid underwater robotic vehicle (HROV) capable of working to the full ocean depth has been developed. The battery powered vehicle operates in two modes: operate as an untethered autonomous vehicle in autonomous underwater vehicle (AUV) mode and operate under remote control connected to the surface vessel by a lightweight, fiber optic tether in remotely operated vehicle (ROV) mode. Considering the hazardous underwater environment at the limiting depth and the hybrid operating modes, survivability has been placed on an equal level with the other design attributes of the HROV since the beginning of the project. This paper reports the survivability design elements for the HROV including basic vehicle design of integrated navigation and integrated communication, emergency recovery strategy, distributed architecture, redundant bus, dual battery package, emergency jettison system and self-repairing control system.

Survivability design for a hybrid underwater vehicle

International Nuclear Information System (INIS)

Wang, Biao; Wu, Chao; Li, Xiang; Zhao, Qingkai; Ge, Tong

2015-01-01

A novel hybrid underwater robotic vehicle (HROV) capable of working to the full ocean depth has been developed. The battery powered vehicle operates in two modes: operate as an untethered autonomous vehicle in autonomous underwater vehicle (AUV) mode and operate under remote control connected to the surface vessel by a lightweight, fiber optic tether in remotely operated vehicle (ROV) mode. Considering the hazardous underwater environment at the limiting depth and the hybrid operating modes, survivability has been placed on an equal level with the other design attributes of the HROV since the beginning of the project. This paper reports the survivability design elements for the HROV including basic vehicle design of integrated navigation and integrated communication, emergency recovery strategy, distributed architecture, redundant bus, dual battery package, emergency jettison system and self-repairing control system

Feasibility of in situ beta ray measurements in underwater environment.

Science.gov (United States)

Park, Hye Min; Park, Ki Hyun; Kang, Sung Won; Joo, Koan Sik

2017-09-01

We describe an attempt at the development of an in situ detector for beta ray measurements in underwater environment. The prototype of the in situ detector is based on a CaF2: Eu scintillator using crystal light guide and Si photomultiplier. Tests were conducted using various reference sources for evaluating the linearity and stability of the detector in underwater environment. The system is simple and stable for long-term monitoring, and consumes low power. We show here an effective detection distance of 7 mm and a 2.273 MeV end-point energy spectrum of 90 Sr/ 90 Y when using the system underwater. The results demonstrate the feasibility of in situ beta ray measurements in underwater environment and can be applied for designing an in situ detector for radioactivity measurement in underwater environment. The in situ detector can also have other applications such as installation on the marine monitoring platform and quantitative analysis of radionuclides. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimization of an Intelligent Controller for an Unmanned Underwater Vehicle

Directory of Open Access Journals (Sweden)

M. Fauzi Nor Shah

2011-08-01

Full Text Available Underwater environment poses a difficult challenge for autonomous underwater navigation. A standard problem of underwater vehicles is to maintain it position at a certain depth in order to perform desired operations. An effective controller is required for this purpose and hence the design of a depth controller for an unmanned underwater vehicle is described in this paper. The control algorithm is simulated by using the marine guidance navigation and control simulator. The project shows a radial basis function metamodel can be used to tune the scaling factors of a fuzzy logic controller. By using offline optimization approach, a comparison between genetic algorithm and metamodeling has been done to minimize the integral square error between the set point and the measured depth of the underwater vehicle. The results showed that it is possible to obtain a reasonably good error using metamodeling approach in much a shorter time compared to the genetic algorithm approach.

A bio-inspired electrocommunication system for small underwater robots.

Science.gov (United States)

Wang, Wei; Liu, Jindong; Xie, Guangming; Wen, Li; Zhang, Jianwei

2017-03-29

Weakly electric fishes (Gymnotid and Mormyrid) use an electric field to communicate efficiently (termed electrocommunication) in the turbid waters of confined spaces where other communication modalities fail. Inspired by this biological phenomenon, we design an artificial electrocommunication system for small underwater robots and explore the capabilities of such an underwater robotic communication system. An analytical model for electrocommunication is derived to predict the effect of the key parameters such as electrode distance and emitter current of the system on the communication performance. According to this model, a low-dissipation, and small-sized electrocommunication system is proposed and integrated into a small robotic fish. We characterize the communication performance of the robot in still water, flowing water, water with obstacles and natural water conditions. The results show that underwater robots are able to communicate electrically at a speed of around 1 k baud within about 3 m with a low power consumption (less than 1 W). In addition, we demonstrate that two leader-follower robots successfully achieve motion synchronization through electrocommunication in the three-dimensional underwater space, indicating that this bio-inspired electrocommunication system is a promising setup for the interaction of small underwater robots.

Disposition of excess weapons plutonium from dismantled weapons

International Nuclear Information System (INIS)

Jardine, L.J.

1997-01-01

With the end of the Cold War and the implementation of various nuclear arms reduction agreements, US and Russia have been actively dismantling tens of thousands of nuclear weapons. As a result,large quantities of fissile materials, including more than 100 (tonnes?) of weapons-grade Pu, have become excess to both countries' military needs. To meet nonproliferation goals and to ensure the irreversibility of nuclear arms reductions, this excess weapons Pu must be placed in secure storage and then, in timely manner, either used in nuclear reactors as fuel or discarded in geologic repositories as solid waste. This disposition in US and Russia must be accomplished in a safe, secure manner and as quickly as practical. Storage of this Pu is a prerequisite to any disposition process, but the length of storage time is unknown. Whether by use as fuel or discard as solid waste, disposition of that amount of Pu will require decades--and perhaps longer, if disposition operations encounter delays. Neither US nor Russia believes that long-term secure storage is a substitute for timely disposition of excess Pu, but long-term, safe, secure storage is a critical element of all excess Pu disposition activities

UTOFIA: an underwater time-of-flight image acquisition system

Science.gov (United States)

Driewer, Adrian; Abrosimov, Igor; Alexander, Jonathan; Benger, Marc; O'Farrell, Marion; Haugholt, Karl Henrik; Softley, Chris; Thielemann, Jens T.; Thorstensen, Jostein; Yates, Chris

2017-10-01

In this article the development of a newly designed Time-of-Flight (ToF) image sensor for underwater applications is described. The sensor is developed as part of the project UTOFIA (underwater time-of-flight image acquisition) funded by the EU within the Horizon 2020 framework. This project aims to develop a camera based on range gating that extends the visible range compared to conventional cameras by a factor of 2 to 3 and delivers real-time range information by means of a 3D video stream. The principle of underwater range gating as well as the concept of the image sensor are presented. Based on measurements on a test image sensor a pixel structure that suits best to the requirements has been selected. Within an extensive characterization underwater the capability of distance measurements in turbid environments is demonstrated.

Techniques to eliminate nuclear weapons testing infrastructure at former Semipalatinsk test site

International Nuclear Information System (INIS)

Erofeev, I.E.; Kovalev, V.V.

2003-01-01

It was at the former Semipalatinsk Test Site where for the first time in the world the nuclear weapons testing infrastructure elimination was put into practice. Fundamentally new procedures for blasting operations have been developed by specialists of the Kazakh State Research and Production Center of Blasting Operations (KSCBO), National Nuclear Center of the Republic of Kazakhstan (NNC) and Degelen Enterprise to enhance reliability and provide safety during elimination of various objects and performance of large-scale experiments. (author)

Underwater photogrammetry successful in Spain and France

International Nuclear Information System (INIS)

Anon.

1988-01-01

Underwater photogrammetry has been used to measure distortions in fuel assembly alignment pins in the upper internals of the Almarez and Dampierre PWRs. Photogrammetry is a three-dimensional precision measurement method using photographic techniques for the on-site measurement phase. On the strength of the operations at the two PWRs, underwater photogrammetry is now considered as a practical and effective technique for dimensional inspection at nuclear plants. (U.K.)

OPTICAL correlation identification technology applied in underwater laser imaging target identification

Science.gov (United States)

Yao, Guang-tao; Zhang, Xiao-hui; Ge, Wei-long

2012-01-01

The underwater laser imaging detection is an effective method of detecting short distance target underwater as an important complement of sonar detection. With the development of underwater laser imaging technology and underwater vehicle technology, the underwater automatic target identification has gotten more and more attention, and is a research difficulty in the area of underwater optical imaging information processing. Today, underwater automatic target identification based on optical imaging is usually realized with the method of digital circuit software programming. The algorithm realization and control of this method is very flexible. However, the optical imaging information is 2D image even 3D image, the amount of imaging processing information is abundant, so the electronic hardware with pure digital algorithm will need long identification time and is hard to meet the demands of real-time identification. If adopt computer parallel processing, the identification speed can be improved, but it will increase complexity, size and power consumption. This paper attempts to apply optical correlation identification technology to realize underwater automatic target identification. The optics correlation identification technology utilizes the Fourier transform characteristic of Fourier lens which can accomplish Fourier transform of image information in the level of nanosecond, and optical space interconnection calculation has the features of parallel, high speed, large capacity and high resolution, combines the flexibility of calculation and control of digital circuit method to realize optoelectronic hybrid identification mode. We reduce theoretical formulation of correlation identification and analyze the principle of optical correlation identification, and write MATLAB simulation program. We adopt single frame image obtained in underwater range gating laser imaging to identify, and through identifying and locating the different positions of target, we can improve

Deep Learning Methods for Underwater Target Feature Extraction and Recognition

Directory of Open Access Journals (Sweden)

Gang Hu

2018-01-01

Full Text Available The classification and recognition technology of underwater acoustic signal were always an important research content in the field of underwater acoustic signal processing. Currently, wavelet transform, Hilbert-Huang transform, and Mel frequency cepstral coefficients are used as a method of underwater acoustic signal feature extraction. In this paper, a method for feature extraction and identification of underwater noise data based on CNN and ELM is proposed. An automatic feature extraction method of underwater acoustic signals is proposed using depth convolution network. An underwater target recognition classifier is based on extreme learning machine. Although convolution neural networks can execute both feature extraction and classification, their function mainly relies on a full connection layer, which is trained by gradient descent-based; the generalization ability is limited and suboptimal, so an extreme learning machine (ELM was used in classification stage. Firstly, CNN learns deep and robust features, followed by the removing of the fully connected layers. Then ELM fed with the CNN features is used as the classifier to conduct an excellent classification. Experiments on the actual data set of civil ships obtained 93.04% recognition rate; compared to the traditional Mel frequency cepstral coefficients and Hilbert-Huang feature, recognition rate greatly improved.

Underwater video enhancement using multi-camera super-resolution

Science.gov (United States)

Quevedo, E.; Delory, E.; Callicó, G. M.; Tobajas, F.; Sarmiento, R.

2017-12-01

Image spatial resolution is critical in several fields such as medicine, communications or satellite, and underwater applications. While a large variety of techniques for image restoration and enhancement has been proposed in the literature, this paper focuses on a novel Super-Resolution fusion algorithm based on a Multi-Camera environment that permits to enhance the quality of underwater video sequences without significantly increasing computation. In order to compare the quality enhancement, two objective quality metrics have been used: PSNR (Peak Signal-to-Noise Ratio) and the SSIM (Structural SIMilarity) index. Results have shown that the proposed method enhances the objective quality of several underwater sequences, avoiding the appearance of undesirable artifacts, with respect to basic fusion Super-Resolution algorithms.

Restoration and Enhancement of Underwater Images Based on Bright Channel Prior

Directory of Open Access Journals (Sweden)

Yakun Gao

2016-01-01

Full Text Available This paper proposed a new method of underwater images restoration and enhancement which was inspired by the dark channel prior in image dehazing field. Firstly, we proposed the bright channel prior of underwater environment. By estimating and rectifying the bright channel image, estimating the atmospheric light, and estimating and refining the transmittance image, eventually underwater images were restored. Secondly, in order to rectify the color distortion, the restoration images were equalized by using the deduced histogram equalization. The experiment results showed that the proposed method could enhance the quality of underwater images effectively.

Evaluation of Underwater Adhesives and Friction Coatings for In Situ Attachment of Fiber Optic Sensor System for Subsea Applications

Science.gov (United States)

Tang, Henry H.; Le, Suy Q.; Orndoff, Evelyne S.; Smith, Frederick D.; Tapia, Alma S.; Brower, David V.

2012-01-01

Integrity and performance monitoring of subsea pipelines and structures provides critical information for managing offshore oil and gas production operation and preventing environmentally damaging and costly catastrophic failure. Currently pipeline monitoring devices require ground assembly and installation prior to the underwater deployment of the pipeline. A monitoring device that could be installed in situ on the operating underwater structures could enhance the productivity and improve the safety of current offshore operation. Through a Space Act Agreement (SAA) between the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) and Astro Technology, Inc. (ATI), JSC provides technical expertise and testing facilities to support the development of fiber optic sensor technologies by ATI. This paper details the first collaboration effort between NASA JSC and ATI in evaluating underwater applicable adhesives and friction coatings for attaching fiber optic sensor system to subsea pipeline. A market survey was conducted to examine different commercial ]off ]the ]shelf (COTS) underwater adhesive systems and to select adhesive candidates for testing and evaluation. Four COTS epoxy based underwater adhesives were selected and evaluated. The adhesives were applied and cured in simulated seawater conditions and then evaluated for application characteristics and adhesive strength. The adhesive that demonstrated the best underwater application characteristics and highest adhesive strength were identified for further evaluation in developing an attachment system that could be deployed in the harsh subsea environment. Various friction coatings were also tested in this study to measure their shear strengths for a mechanical clamping design concept for attaching fiber optic sensor system. A COTS carbide alloy coating was found to increase the shear strength of metal to metal clamping interface by up to 46 percent. This study provides valuable data for

Verification of Chemical Weapons Destruction

International Nuclear Information System (INIS)

Lodding, J.

2010-01-01

The Chemical Weapons Convention is the only multilateral treaty that bans completely an entire category of weapons of mass destruction under international verification arrangements. Possessor States, i.e. those that have chemical weapons stockpiles at the time of becoming party to the CWC, commit to destroying these. All States undertake never to acquire chemical weapons and not to help other States acquire such weapons. The CWC foresees time-bound chemical disarmament. The deadlines for destruction for early entrants to the CWC are provided in the treaty. For late entrants, the Conference of States Parties intervenes to set destruction deadlines. One of the unique features of the CWC is thus the regime for verifying destruction of chemical weapons. But how can you design a system for verification at military sites, while protecting military restricted information? What degree of assurance is considered sufficient in such circumstances? How do you divide the verification costs? How do you deal with production capability and initial declarations of existing stockpiles? The founders of the CWC had to address these and other challenges in designing the treaty. Further refinement of the verification system has followed since the treaty opened for signature in 1993 and since inspection work was initiated following entry-into-force of the treaty in 1997. Most of this work concerns destruction at the two large possessor States, Russia and the United States. Perhaps some of the lessons learned from the OPCW experience may be instructive in a future verification regime for nuclear weapons. (author)

Weapons of mass destruction - current security threat

International Nuclear Information System (INIS)

Durdiak, J.; Gafrik, A.; Pulis, P.; Susko, M.

2005-01-01

This publication brings a complex and comprehensive view of the weapons of mass destruction phenomenon in the context of present military and political situation. It emphasizes the threat posed by proliferation of these destructive devices and their carriers as well as the threat present in their possession by unpredictable totalitarian regimes or terrorist groups. The publication is structured into four basic parts: Introduction Into The Topic, Nuclear Weapons, Chemical Weapons and Biological Weapons. The Introduction reflects the latest developments on the field of military technologies, which lead to the development of new destructive devices with characteristics comparable to basic types of WMDs - nuclear, chemical and biological. Based on the definition of WMD as 'weapon systems with enormous impact causing mass destruction, population, equipment and material losses', the modern mass destruction devices are assorted here, such as ecological, radiological and beam weapons, aerosol and container intelligent ammunition, the outburst of dangerous chemical substances from infrastructure, non-conventional weapons and military devices. The Nuclear Weapons part depicts the most destructive device of mass destruction mankind ever invented in close detail. It maps the history of most significant discoveries in nuclear physics, development and construction of the first nuclear weapons, accumulation of nuclear warheads and their carriers in the Cold war era, attempts of nuclear disarmament and reducing the number of nuclear weapons in possession of superpowers and their proliferation in the world's crisis regions including North Korea and Iran. The chapters devoted to theoretical grounds and physical principles of nuclear and thermonuclear weapons' functioning, the main categories and types, as well as destructive effects and consequences of use contain an adequate mathematical apparatus. This chapter's conclusion brings the overview of nuclear armament of states that

Remarks on the observability of single beacon underwater navigation

DEFF Research Database (Denmark)

Jouffroy, Jerome; Ross, Andrew

This paper contributes a simple and intuitive result in the analysis of underwater navigation using a single ranging beacon. This analysis should help with the design of small and lightweight underwater vehicles by reducing the amount of instrumentation required for accurate navigation. The concept...

Efficient Weibull channel model for salinity induced turbulent underwater wireless optical communications

KAUST Repository

Oubei, Hassan M.

2017-12-13

Recent advances in underwater wireless optical communications necessitate a better understanding of the underwater channel. We propose the Weibull model to characterize the fading of salinity induced turbulent underwater wireless optical channels. The model shows an excellent agreement with the measured data under all channel conditions.

Global strike hypersonic weapons

Science.gov (United States)

Lewis, Mark J.

2017-11-01

Beginning in the 1940's, the United States has pursued the development of hypersonic technologies, enabling atmospheric flight in excess of five times the speed of sound. Hypersonic flight has application to a range of military and civilian applications, including commercial transport, space access, and various weapons and sensing platforms. A number of flight tests of hypersonic vehicles have been conducted by countries around the world, including the United States, Russia, and China, that could lead the way to future hypersonic global strike weapon systems. These weapons would be especially effective at penetrating conventional defenses, and could pose a significant risk to national security.

A Secure Communication Suite for Underwater Acoustic Sensor Networks

Directory of Open Access Journals (Sweden)

Angelica Lo Duca

2012-11-01

Full Text Available In this paper we describe a security suite for Underwater Acoustic Sensor Networks comprising both fixed and mobile nodes. The security suite is composed of a secure routing protocol and a set of cryptographic primitives aimed at protecting the confidentiality and the integrity of underwater communication while taking into account the unique characteristics and constraints of the acoustic channel. By means of experiments and simulations based on real data, we show that the suite is suitable for an underwater networking environment as it introduces limited, and sometimes negligible, communication and power consumption overhead.

Underwater Acoustic Target Tracking: A Review

Science.gov (United States)

Han, Ying; Fan, Liying

2018-01-01

Advances in acoustic technology and instrumentation now make it possible to explore marine resources. As a significant component of ocean exploration, underwater acoustic target tracking has aroused wide attention both in military and civil fields. Due to the complexity of the marine environment, numerous techniques have been proposed to obtain better tracking performance. In this paper, we survey over 100 papers ranging from innovative papers to the state-of-the-art in this field to present underwater tracking technologies. Not only the related knowledge of acoustic tracking instrument and tracking progress is clarified in detail, but also a novel taxonomy method is proposed. In this paper, algorithms for underwater acoustic target tracking are classified based on the methods used as: (1) instrument-assisted methods; (2) mode-based methods; (3) tracking optimization methods. These algorithms are compared and analyzed in the aspect of dimensions, numbers, and maneuvering of the tracking target, which is different from other survey papers. Meanwhile, challenges, countermeasures, and lessons learned are illustrated in this paper. PMID:29301318

Afocal viewport optics for underwater imaging

Science.gov (United States)

Slater, Dan

2014-09-01

A conventional camera can be adapted for underwater use by enclosing it in a sealed waterproof pressure housing with a viewport. The viewport, as an optical interface between water and air needs to consider both the camera and water optical characteristics while also providing a high pressure water seal. Limited hydrospace visibility drives a need for wide angle viewports. Practical optical interfaces between seawater and air vary from simple flat plate windows to complex water contact lenses. This paper first provides a brief overview of the physical and optical properties of the ocean environment along with suitable optical materials. This is followed by a discussion of the characteristics of various afocal underwater viewport types including flat windows, domes and the Ivanoff corrector lens, a derivative of a Galilean wide angle camera adapter. Several new and interesting optical designs derived from the Ivanoff corrector lens are presented including a pair of very compact afocal viewport lenses that are compatible with both in water and in air environments and an afocal underwater hyper-hemispherical fisheye lens.

Underwater running device

International Nuclear Information System (INIS)

Kogure, Sumio; Matsuo, Takashiro; Yoshida, Yoji

1996-01-01

An underwater running device for an underwater inspection device for detecting inner surfaces of a reactor or a water vessel has an outer frame and an inner frame, and both of them are connected slidably by an air cylinder and connected rotatably by a shaft. The outer frame has four outer frame legs, and each of the outer frame legs is equipped with a sucker at the top end. The inner frame has four inner frame legs each equipped with a sucker at the top end. The outer frame legs and the inner frame legs are each connected with the outer frame and the inner frame by the air cylinder. The outer and the inner frame legs can be elevated or lowered (or extended or contracted) by the air cylinder. The sucker is connected with a jet pump-type negative pressure generator. The device can run and move by repeating attraction and releasing of the outer frame legs and the inner frame legs alternately while maintaining the posture of the inspection device stably. (I.N.)

Smelling and Tasting Underwater.

Science.gov (United States)

Atema, Jelle

1980-01-01

Discusses differences between smell and taste, comparing these senses in organisms in aquatic and terrestrial environments. Describes the chemical environment underwater and in air, differences in chemoreceptors to receive stimuli, and the organs, brain, and behavior involved in chemoreception. (CS)

Polarization Calculation and Underwater Target Detection Inspired by Biological Visual Imaging

Directory of Open Access Journals (Sweden)

Jie Shen

2014-04-01

Full Text Available In challenging underwater environments, the polarization parameter maps calculated by the Stokes model are characterized by the high noise and error, harassing the underwater target detection tasks. In order to solve this problem, this paper proposes a novel bionic polarization calculation and underwater target detection method by modeling the visual system of mantis shrimps. This system includes many operators including a polarization-opposition calculation, a factor optimization and a visual neural network model. A calibration learning method is proposed to search the optimal value of the factors in the linear subtraction model. Finally, a six-channel visual neural network model is proposed to detect the underwater targets. Experimental results proved that the maps produced by the polarization-opposition parameter is more accurate and have lower noise than that produced by the Stokes parameter, achieving better performance in underwater target detection tasks.

For a convention for nuclear weapon elimination

International Nuclear Information System (INIS)

2008-03-01

This document contains two texts linked with the project of an international convention for the elimination of nuclear weapons (the text of this project has been sent to the UN General Secretary and is part of an international campaign to abolish nuclear weapons, ICAN). These two texts are contributions presented in London at the Global Summit for a Nuclear Weapon-free World. The first one calls into question the deterrence principle and the idea of a nuclear weapon-based security. It calls for different forms of action to promote a nuclear weapon-free world. The second text stresses the role and the responsibility of states with nuclear weapons in nuclear disarmament and in the reinforcement of the nuclear non proliferation treaty (NPT)

Application of underwater radon measurements in geology

Energy Technology Data Exchange (ETDEWEB)

Varhegyi, A.; Baranyi, I.; Gerzson, I. (Mecsek Ore Mining Enterprise, Pecs (Hungary)); Somogyi, G.; Hakl, J.; Hunyadi, I. (Magyar Tudomanyos Akademia, Debrecen (Hungary). Atommag Kutato Intezete)

1988-01-01

Based on the observed phenomenon of geogas migration in microbubble form from deeper regions, the authors have developed a new model for the vertical transport of radon released from deeper sources. The physical properties of the rock relating to the upflow of microbubbles below the groundwater level are considered and the radon transport parameter of rocks is introduced. The vertical distribution of radon concentration in the case of a multi-layered geological model is given and the penetration depth of underwater radon measurements is examined. Aspects of underwater radon detection by the nuclear track detector technique are analyzed. The radon transport model gives a new theoretical basis for several applications of radon measurements in geology. The advantages of underwater radon detection have already been proved in uranium exploration. Further geological applications are proposed in earthquake prediction, in volcanology, in the survey of active faults and thermal waters. (author).

Object detection from images obtained through underwater turbulence medium

Science.gov (United States)

Furhad, Md. Hasan; Tahtali, Murat; Lambert, Andrew

2017-09-01

Imaging through underwater experiences severe distortions due to random fluctuations of temperature and salinity in water, which produces underwater turbulence through diffraction limited blur. Lights reflecting from objects perturb and attenuate contrast, making the recognition of objects of interest difficult. Thus, the information available for detecting underwater objects of interest becomes a challenging task as they have inherent confusion among the background, foreground and other image properties. In this paper, a saliency-based approach is proposed to detect the objects acquired through an underwater turbulent medium. This approach has drawn attention among a wide range of computer vision applications, such as image retrieval, artificial intelligence, neuro-imaging and object detection. The image is first processed through a deblurring filter. Next, a saliency technique is used on the image for object detection. In this step, a saliency map that highlights the target regions is generated and then a graph-based model is proposed to extract these target regions for object detection.

Nuclear power and weapons proliferation

International Nuclear Information System (INIS)

Greenwood, T.; Rathjens, C.W.; Ruina, J.

1977-01-01

The relationship between nuclear weapons development and nuclear electric power is examined. A brief description of nuclear weapons design is first given. This is then followed by a discussion of various aspects of nuclear power technology and of how they affect a nuclear weapon programme. These include fuel cycles, chemical reprocessing of spent fuel, uranium enrichment, and the control of dissemination of nuclear technology. In conclusion there is a discussion of possible political and institutional controls for limiting nuclear proliferation. (U.K.)

Remote Underwater Characterization System - Innovative Technology Summary Report

International Nuclear Information System (INIS)

Willis, W.D.

1999-01-01

Characterization and inspection of water-cooled and moderated nuclear reactors and fuel storage pools requires equipment capable of operating underwater. Similarly, the deactivation and decommissioning of older nuclear facilities often requires the facility owner to accurately characterize underwater structures and equipment which may have been sitting idle for years. The Remote Underwater Characterization System (RUCS) is a small, remotely operated submersible vehicle intended to serve multiple purposes in underwater nuclear operations. It is based on the commercially-available Scallop vehicle 1 , but has been modified by the Department of Energys Robotics Technology Development Program to add auto-depth control, and vehicle orientation and depth monitoring at the operator control panel. The RUCS is designed to provide visual and gamma radiation characterization, even in confined or limited access areas. It was demonstrated in August 1998 at the Idaho National Engineering and Environmental Laboratory (INEEL) as part of the INEEL Large Scale Demonstration and Deployment Project. During the demonstration it was compared in a ''head-to-head fashion with the baseline characterization technology. This paper summarizes the results of the demonstration and lessons learned; comparing and contrasting both technologies in the areas of cost, visual characterization, radiological characterization, and overall operations

DE-Sync: A Doppler-Enhanced Time Synchronization for Mobile Underwater Sensor Networks.

Science.gov (United States)

Zhou, Feng; Wang, Qi; Nie, DongHu; Qiao, Gang

2018-05-25

Time synchronization is the foundation of cooperative work among nodes of underwater sensor networks; it takes a critical role in the research and application of underwater sensor networks. Although numerous time synchronization protocols have been proposed for terrestrial wireless sensor networks, they cannot be directly applied to underwater sensor networks. This is because most of them typically assume that the propagation delay among sensor nodes is negligible, which is not the case in underwater sensor networks. Time synchronization is mainly affected by a long propagation delay among sensor nodes due to the low propagation speed of acoustic signals. Furthermore, sensor nodes in underwater tend to experience some degree of mobility due to wind or ocean current, or some other nodes are on self-propelled vehicles, such as autonomous underwater vehicles (AUVs). In this paper, we propose a Doppler-enhanced time synchronization scheme for mobile underwater sensor networks, called DE-Sync. Our new scheme considers the effect of the clock skew during the process of estimating the Doppler scale factor and directly substitutes the Doppler scale factor into linear regression to achieve the estimation of the clock skew and offset. Simulation results show that DE-Sync outperforms existing time synchronization protocols in both accuracy and energy efficiency.

Effects of the use of ABC weapons

International Nuclear Information System (INIS)

Karl-Rueckert, E.

1980-01-01

The effects of ABC-weapons are presented. The various classes of chemical weapons and their effects are discussed. It is pointed out that there is hardly a means of protection against these weapons. (MG) [de

Robotics Vision-based Heuristic Reasoning for Underwater Target Tracking and Navigation

OpenAIRE

Kia, Chua; Arshad, Mohd Rizal

2006-01-01

This paper presents a robotics vision-based heuristic reasoning system for underwater target tracking and navigation. This system is introduced to improve the level of automation of underwater Remote Operated Vehicles (ROVs) operations. A prototype which combines computer vision with an underwater robotics system is successfully designed and developed to perform target tracking and intelligent navigation. This study focuses on developing image processing algorithms and fuzzy inference system ...

Special Weapons

Data.gov (United States)

Federal Laboratory Consortium — Supporting Navy special weapons, the division provides an array of engineering services, technical publication support services, logistics support services, safety...

A review of underwater bio-mimetic propulsion: cruise and fast-start

Science.gov (United States)

Chao, Li-Ming; Cao, Yong-Hui; Pan, Guang

2017-08-01

This paper reviews recent developments in the understanding of underwater bio-mimetic propulsion. Two impressive models of underwater propulsion are considered: cruise and fast-start. First, we introduce the progression of bio-mimetic propulsion, especially underwater propulsion, where some primary conceptions are touched upon. Second, the understanding of flapping foils, considered as one of the most efficient cruise styles of aquatic animals, is introduced, where the effect of kinematics and the shape and flexibility of foils on generating thrust are elucidated respectively. Fast-start propulsion is always exhibited when predator behaviour occurs, and we provide an explicit introduction of corresponding zoological experiments and numerical simulations. We also provide some predictions about underwater bio-mimetic propulsion.

A review of underwater bio-mimetic propulsion: cruise and fast-start

Energy Technology Data Exchange (ETDEWEB)

Chao, Li-Ming; Cao, Yong-Hui; Pan, Guang, E-mail: PanGuang_010@163.com [School of Marine Science and Technology, Northwestern Polytechnical University, Xian 710072 (China)

2017-08-15

This paper reviews recent developments in the understanding of underwater bio-mimetic propulsion. Two impressive models of underwater propulsion are considered: cruise and fast-start. First, we introduce the progression of bio-mimetic propulsion, especially underwater propulsion, where some primary conceptions are touched upon. Second, the understanding of flapping foils, considered as one of the most efficient cruise styles of aquatic animals, is introduced, where the effect of kinematics and the shape and flexibility of foils on generating thrust are elucidated respectively. Fast-start propulsion is always exhibited when predator behaviour occurs, and we provide an explicit introduction of corresponding zoological experiments and numerical simulations. We also provide some predictions about underwater bio-mimetic propulsion. (review)

Nuclear power and nuclear weapons

International Nuclear Information System (INIS)

Vaughen, V.C.A.

1983-01-01

The proliferation of nuclear weapons and the expanded use of nuclear energy for the production of electricity and other peaceful uses are compared. The difference in technologies associated with nuclear weapons and nuclear power plants are described

Cardiovascular response during submaximal underwater treadmill exercise in stroke patients.

Science.gov (United States)

Yoo, Jeehyun; Lim, Kil-Byung; Lee, Hong-Jae; Kwon, Yong-Geol

2014-10-01

To evaluate the cardiovascular response during head-out water immersion, underwater treadmill gait, and land treadmill gait in stroke patients. Ten stroke patients were recruited for underwater and land treadmill gait sessions. Each session was 40 minutes long; 5 minutes for standing rest on land, 5 minutes for standing rest in water or on treadmill, 20 minutes for treadmill walking in water or on land, 5 minutes for standing rest in water or on treadmill, and 5 minutes for standing rest on land. Blood pressure (BP) and heart rate (HR) were measured during each session. In order to estimate the cardiovascular workload and myocardial oxygen demand, the rate pressure product (RPP) value was calculated by multiplying systolic BP (SBP) by HR. SBP, DBP, mean BP (mBP), and RPP decreased significantly after water immersion, but HR was unchanged. During underwater and land treadmill gait, SBP, mBP, DBP, RPP, and HR increased. However, the mean maximum increases in BP, HR and RPP of underwater treadmill walking were significantly lower than that of land treadmill walking. Stroke patients showed different cardiovascular responses during water immersion and underwater gait as opposed to standing and treadmill-walking on land. Water immersion and aquatic treadmill gait may reduce the workload of the cardiovascular system. This study suggested that underwater treadmill may be a safe and useful option for cardiovascular fitness and early ambulation in stroke rehabilitation.

Channel coding for underwater acoustic single-carrier CDMA communication system

Science.gov (United States)

Liu, Lanjun; Zhang, Yonglei; Zhang, Pengcheng; Zhou, Lin; Niu, Jiong

2017-01-01

CDMA is an effective multiple access protocol for underwater acoustic networks, and channel coding can effectively reduce the bit error rate (BER) of the underwater acoustic communication system. For the requirements of underwater acoustic mobile networks based on CDMA, an underwater acoustic single-carrier CDMA communication system (UWA/SCCDMA) based on the direct-sequence spread spectrum is proposed, and its channel coding scheme is studied based on convolution, RA, Turbo and LDPC coding respectively. The implementation steps of the Viterbi algorithm of convolutional coding, BP and minimum sum algorithms of RA coding, Log-MAP and SOVA algorithms of Turbo coding, and sum-product algorithm of LDPC coding are given. An UWA/SCCDMA simulation system based on Matlab is designed. Simulation results show that the UWA/SCCDMA based on RA, Turbo and LDPC coding have good performance such that the communication BER is all less than 10-6 in the underwater acoustic channel with low signal to noise ratio (SNR) from -12 dB to -10dB, which is about 2 orders of magnitude lower than that of the convolutional coding. The system based on Turbo coding with Log-MAP algorithm has the best performance.

A Review of the Emerging Field of Underwater Mass Spectrometry

Directory of Open Access Journals (Sweden)

Emily Chua

2016-11-01

Full Text Available Mass spectrometers are versatile sensor systems, owing to their high sensitivity and ability to simultaneously measure multiple chemical species. Over the last two decades, traditional laboratory-based membrane inlet mass spectrometers have been adapted for underwater use. Underwater mass spectrometry has drastically improved our capability to monitor a broad suite of gaseous compounds (e.g., dissolved atmospheric gases, light hydrocarbons, and volatile organic compounds in the aquatic environment. Here we provide an overview of the progress made in the field of underwater mass spectrometry since its inception in the 1990s to the present. In particular, we discuss the approaches undertaken by various research groups in developing in situ mass spectrometers. We also provide examples to illustrate how underwater mass spectrometers have been used in the field. Finally, we present future trends in the field of in situ mass spectrometry. Most of these efforts are aimed at improving the quality and spatial and temporal scales of chemical measurements in the ocean. By providing up-to-date information on underwater mass spectrometry, this review offers guidance for researchers interested in adapting this technology as well as goals for future progress in the field.

Euclidean reconstruction of natural underwater scenes using optic imagery sequence

Science.gov (United States)

Hu, Han

The development of maritime applications require monitoring, studying and preserving of detailed and close observation on the underwater seafloor and objects. Stereo vision offers advanced technologies to build 3D models from 2D still overlapping optic images in a relatively inexpensive way. However, while image stereo matching is a necessary step in 3D reconstruction procedure, even the most robust dense matching techniques are not guaranteed to work for underwater images due to the challenging aquatic environment. In this thesis, in addition to a detailed introduction and research on the key components of building 3D models from optic images, a robust modified quasi-dense matching algorithm based on correspondence propagation and adaptive least square matching for underwater images is proposed and applied to some typical underwater image datasets. The experiments demonstrate the robustness and good performance of the proposed matching approach.

The Modular Optical Underwater Survey System

Directory of Open Access Journals (Sweden)

Ruhul Amin

2017-10-01

Full Text Available The Pacific Islands Fisheries Science Center deploys the Modular Optical Underwater Survey System (MOUSS to estimate the species-specific, size-structured abundance of commercially-important fish species in Hawaii and the Pacific Islands. The MOUSS is an autonomous stereo-video camera system designed for the in situ visual sampling of fish assemblages. This system is rated to 500 m and its low-light, stereo-video cameras enable identification, counting, and sizing of individuals at a range of 0.5–10 m. The modular nature of MOUSS allows for the efficient and cost-effective use of various imaging sensors, power systems, and deployment platforms. The MOUSS is in use for surveys in Hawaii, the Gulf of Mexico, and Southern California. In Hawaiian waters, the system can effectively identify individuals to a depth of 250 m using only ambient light. In this paper, we describe the MOUSS’s application in fisheries research, including the design, calibration, analysis techniques, and deployment mechanism.

State-of-the-Art System Solutions for Unmanned Underwater Vehicles

Directory of Open Access Journals (Sweden)

A. E. Yilmaz

2009-12-01

Full Text Available Unmanned Underwater Vehicles (UUVs have gained popularity for the last decades, especially for the purpose of not risking human life in dangerous operations. On the other hand, underwater environment introduces numerous challenges in navigation, control and communication of such vehicles. Certainly, this fact makes the development of these vehicles more interesting and engineering-wise more attractive. In this paper, we first revisit the existing technology and methodology for the solution of aforementioned problems, then we try to come up with a system solution of a generic unmanned underwater vehicles.

Terror weapons. Ridding the world of nuclear, biological and chemical weapons - Commission on mass destruction weapons; Armes de terreur. Debarrasser le monde des armes nucleaires, biologiques et chimiques - Commission sur les armes de destruction massive

Energy Technology Data Exchange (ETDEWEB)

Blix, H.; Journe, V.

2010-07-01

This book approaches in 8 chapters the ambitious challenge of ridding the world of all mass destruction weapons: 1 - re-launching disarmament; 2 - terror weapons: nature of threats and answers (weakness of traditional answers, counter-proliferation); 3 - nuclear weapons: preventing proliferation and terrorism, reducing threat and nuclear weapons number, from regulation to banning); 4 - biological or toxin weapons; 5 - chemical weapons; 6 - vectors, anti-missile defenses and space weapons; 7 - exports control, international assistance and non-governmental actors; 8 - respect, verification, enforcement and role of the United Nations. The recommendations and works of the Commission are presented in appendix together with the declaration adopted on April 30, 2009. (J.S.)

The aquatic tympanic ear: convergent adaptations for underwater hearing in three tetrapods

DEFF Research Database (Denmark)

Christensen-Dalsgaard, Jakob; Wahlberg, Magnus; Larsen, Ole Næsbye

pressure, low particle motion medium, and the consequence is that an efficient underwater ear is sensitive to sound pressure. It is often stated that underwater hearing can work efficiently without a middle ear apparatus by bone conduction, since sound is transmitted from water to inner ear tissue...... is modified (cartilaginous or partly cartilaginous). In all three species, the lowest threshold to underwater sound is at this peak frequency and is around 80 dB re 1 µPa. The sensitivity to sound pressure is slightly lower in water than in air, making underwater hearing much more efficient in terms of sound...

Collective Modular Underwater Robotic System for Long-Term Autonomous Operation

DEFF Research Database (Denmark)

Christensen, David Johan; Andersen, Jens Christian; Blanke, Mogens

This paper provides a brief overview of an underwater robotic system for autonomous inspection in confined offshore underwater structures. The system, which is currently in development, consist of heterogeneous modular robots able to physically dock and communicate with other robots, transport...

Underwater Sensor Networks: A New Energy Efficient and Robust Architecture

NARCIS (Netherlands)

Climent, Salvador; Capella, Juan Vincente; Meratnia, Nirvana; Serrano, Juan José

2012-01-01

The specific characteristics of underwater environments introduce new challenges for networking protocols. In this paper, a specialized architecture for underwater sensor networks (UWSNs) is proposed and evaluated. Experiments are conducted in order to analyze the suitability of this protocol for

Underwater methods for study of salmonids in the Intermountain West

Science.gov (United States)

Russell F. Thurow

1994-01-01

This guide describes underwater methods using snorkeling gear to study fish populations in flowing waters of the Intermountain West. It outlines procedures for estimating salmonid abundance and habitat use and provides criteria for identifying and estimating the size of fish underwater.

Underwater detection by using ultrasonic sensor

Science.gov (United States)

Bakar, S. A. A.; Ong, N. R.; Aziz, M. H. A.; Alcain, J. B.; Haimi, W. M. W. N.; Sauli, Z.

2017-09-01

This paper described the low cost implementation of hardware and software in developing the system of ultrasonic which can visualize the feedback of sound in the form of measured distance through mobile phone and monitoring the frequency of detection by using real time graph of Java application. A single waterproof transducer of JSN-SR04T had been used to determine the distance of an object based on operation of the classic pulse echo detection method underwater. In this experiment, the system was tested by placing the housing which consisted of Arduino UNO, Bluetooth module of HC-06, ultrasonic sensor and LEDs at the top of the box and the transducer was immersed in the water. The system which had been tested for detection in vertical form was found to be capable of reporting through the use of colored LEDs as indicator to the relative proximity of object distance underwater form the sensor. As a conclusion, the system can detect the presence of an object underwater within the range of ultrasonic sensor and display the measured distance onto the mobile phone and the real time graph had been successfully generated.

Nuclear weapons proliferation problem: can we lead without leadership

International Nuclear Information System (INIS)

Stathakis, G.J.

1977-01-01

The immediate problem facing us with respect to proliferation and nuclear power involves reprocessing and the availability of plutonium from reprocessing plants. One solution supported by the Atomic Industrial Forum is that reprocessing centers be restricted to locations in those industrial nations already having weapons capability and that the energy of the reprocessed plutonium be returned to the user nation in the form of low enriched uranium. Thus, the plutonium would remain where it would not add to problems of proliferation

Task Allocation and Path Planning for Collaborative Autonomous Underwater Vehicles Operating through an Underwater Acoustic Network

Directory of Open Access Journals (Sweden)

Yueyue Deng

2013-01-01

Full Text Available Dynamic and unstructured multiple cooperative autonomous underwater vehicle (AUV missions are highly complex operations, and task allocation and path planning are made significantly more challenging under realistic underwater acoustic communication constraints. This paper presents a solution for the task allocation and path planning for multiple AUVs under marginal acoustic communication conditions: a location-aided task allocation framework (LAAF algorithm for multitarget task assignment and the grid-based multiobjective optimal programming (GMOOP mathematical model for finding an optimal vehicle command decision given a set of objectives and constraints. Both the LAAF and GMOOP algorithms are well suited in poor acoustic network condition and dynamic environment. Our research is based on an existing mobile ad hoc network underwater acoustic simulator and blind flooding routing protocol. Simulation results demonstrate that the location-aided auction strategy performs significantly better than the well-accepted auction algorithm developed by Bertsekas in terms of task-allocation time and network bandwidth consumption. We also demonstrate that the GMOOP path-planning technique provides an efficient method for executing multiobjective tasks by cooperative agents with limited communication capabilities. This is in contrast to existing multiobjective action selection methods that are limited to networks where constant, reliable communication is assumed to be available.

Cooperative OFDM underwater acoustic communications

CERN Document Server

Cheng, Xilin; Cheng, Xiang

2016-01-01

Following underwater acoustic channel modeling, this book investigates the relationship between coherence time and transmission distances. It considers the power allocation issues of two typical transmission scenarios, namely short-range transmission and medium-long range transmission. For the former scenario, an adaptive system is developed based on instantaneous channel state information. The primary focus is on cooperative dual-hop orthogonal frequency division multiplexing (OFDM). This book includes the decomposed fountain codes designed to enable reliable communications with higher energy efficiency. It covers the Doppler Effect, which improves packet transmission reliability for effective low-complexity mirror-mapping-based intercarrier interference cancellation schemes capable of suppressing the intercarrier interference power level. Designed for professionals and researchers in the field of underwater acoustic communications, this book is also suitable for advanced-level students in electrical enginee...

Bugs and gas: Agreements banning chemical and biological weapons

Science.gov (United States)

Mikulak, Robert P.

2017-11-01

The use of chemical or biological weapons, whether by a State or terrorists, continues to be a serious security concern. Both types of weapons are prohibited by multilateral treaties that have very broad membership, but both the Biological Weapons Convention and the Chemical Weapons Convention are facing major challenges. In particular, the continued use of chemical weapons in the Syrian civil war by government forces risks eroding the norm against the use of such weapons. This paper briefly explore the recent history of efforts to constrain chemical and biological weapons and outlines challenges for the future.

ULTRA: Underwater Localization for Transit and Reconnaissance Autonomy

Science.gov (United States)

Huntsberger, Terrance L.

2013-01-01

This software addresses the issue of underwater localization of unmanned vehicles and the inherent drift in their onboard sensors. The software gives a 2 to 3 factor of improvement over the state-of-the-art underwater localization algorithms. The software determines the localization (position, heading) of an AUV (autonomous underwater vehicle) in environments where there is no GPS signal. It accomplishes this using only the commanded position, onboard gyros/accelerometers, and the bathymetry of the bottom provided by an onboard sonar system. The software does not rely on an onboard bathymetry dataset, but instead incrementally determines the position of the AUV while mapping the bottom. In order to enable long-distance underwater navigation by AUVs, a localization method called ULTRA uses registration of the bathymetry data products produced by the onboard forward-looking sonar system for hazard avoidance during a transit to derive the motion and pose of the AUV in order to correct the DR (dead reckoning) estimates. The registration algorithm uses iterative point matching (IPM) combined with surface interpolation of the Iterative Closest Point (ICP) algorithm. This method was used previously at JPL for onboard unmanned ground vehicle localization, and has been optimized for efficient computational and memory use.

Nuclear experts and nuclear weapons proliferation

International Nuclear Information System (INIS)

Mueller, H.

1979-01-01

In Germany the issue of nuclear weapons proliferation has attracted scant attention. Most potential nuclear weapon states are important trade partners of the FRG and, since further proliferation of nuclear weapons could worsen conflicts involving these, it should be in the FRG's interest to limit proliferation. The security of the FRG is also dependent on the common interest of the great powers to avoid nuclear war. The contradictory positions of Usa and the USSR on nuclear weapons policy regarding themselves and non-nuclear weapon states encourages less developed countries to see nuclear weaponry as useful. The NPT and IAEA safeguards have only limited inhibiting effect. The nuclear export policy of the FRG has been dominated by short term economic advantage, neglecting the negative long term effects of decreased political stability. The FRG should formulate a policy based on self-restraint, positive stimuli and extension of controls, using its economic strength to deter proliferation. (JIW)

Underwater laser cladding and seal welding for INCONEL 52

International Nuclear Information System (INIS)

Tamura, Masataka; Kouno, Wataru; Makino, Yoshinobu; Kawano, Shohei; Yoda, Masaki

2007-01-01

Recently, stress corrosion cracking (SCC) has been observed at aged components of nuclear power plants under water environment and high exposure of radiation. Toshiba has been developing both an underwater laser welding directly onto surface of the aged components as maintenance and repair techniques. This paper reports underwater laser cladding and seal welding for INCONEL 52. (author)

Reframing the debate against nuclear weapons

International Nuclear Information System (INIS)

Tyson, Rhianna

2005-01-01

'Some 35,000 nuclear weapons remain in the arsenals of the nuclear powers, with thousands still deployed on hair-trigger alert. Whatever rationale these weapons may once have had has long since dwindled. Political, moral, and legal constraints on actually using them further undermine their strategic utility without, however, reducing the risks of inadvertent war or proliferation. The objective of nuclear non-proliferation is not helped by the fact that the nuclear weapon States continue to insist that those weapons in their hands enhance security, while in the hands of others they are a threat to world peace. If we were making steady progress towards disarmament, this situation would be less alarming. Unfortunately, the reverse is true.' - United Nations Secretary-General Kofi Annan. 'Something is wrong with the nuclear disarmament and non-proliferation regime. Although seemingly well-equipped with an arsenal of legal and political mechanisms, such as the Nuclear Non-Proliferation Treaty (NPT), the 1996 Advisory Opinion of the International Court of Justice (ICJ), decades' worth of General Assembly (GA) resolutions and even a recent slew of ad-hoc, plurilateral initiatives such as the Proliferation Security Initiative, the regime created to prevent the catastrophe of nuclear war remains inadequate. This insufficiency is even starker when viewed in relation to the regimes controlling other weapons of mass destruction. Despite its own challenges, the Organization for the Prohibition on Chemical Weapons remains relatively well-funded and well-situated to facilitate the implementation of the Chemical Weapons Convention (CWC). Even the Biological and Toxin Weapons Convention (BTWC), while still lacking the necessary verification mechanisms, has managed to effectively criminalize not just the use and threat of use of biological weapons, but also their production, development and stockpiling. Meanwhile, the anti-nuclear regime seems to be faltering. Progress made in

Safety aspects for underwater vehicles

Digital Repository Service at National Institute of Oceanography (India)

Madhan, R.; Navelkar, G.S.; Desa, E.S.; Afzulpurkar, S.; Prabhudesai, S.P.; Dabholkar, N.; Mascarenhas, A.A.M.Q.; Maurya, P.

instrumentation is intelligent small Autonomous Underwater Vehicles (AUV’s), autonomous profilers, gliders [1], etc. The ultimate aim in all autonomous platforms research and development is to reach the stage of unescorted missions with minimum failures...

The WODA guidance paper on underwater sound from dredging (abstract)

NARCIS (Netherlands)

Thomsen, F.; Borsani, F.; Clarke, D.; Jong, C.A.F. de; Witt, P. de; Holtkamp, M.; Goethals, F.; San Martin, E.; Spadaro, P.; Raalte, G. van; Jensen, A.

2013-01-01

The World Organisation of Dredging Associations (WODA) has identified underwater sound as an environmental issue that needs further consideration. A WODA Expert Group on Underwater Sound (WEGUS) was established to provide a guidance paper on dredging sound, impact on aquatic biota and advice on

Defect detectability of eddy current testing for underwater laser beam welding

International Nuclear Information System (INIS)

Ueno, Souichi; Kobayashi, Noriyasu; Ochiai, Makoto; Kasuya, Takashi; Yuguchi, Yasuhiro

2011-01-01

We clarified defect detectability of eddy current testing (ECT) as a surface inspection technique for underwater laser beam welding works of dissimilar metal welding (DMW) of reactor vessel nozzle. The underwater laser beam welding procedure includes groove caving as a preparation, laser beam welding in the grooves and welded surface grinding as a post treatment. Therefore groove and welded surface inspections are required in the underwater condition. The ECT is a major candidate as this inspection technique because a penetrant testing is difficult to perform in the underwater condition. Several kinds of experiments were curried out using a cross coil an ECT probe and ECT data acquisition system in order to demonstrate the ECT defect detectability. We used specimens, simulating groove and DMW materials at an RV nozzle, with electro-discharge machining (EDM) slits over it. Additionally, we performed a detection test for artificial stress corrosion cracking (SCC) defects. From these experimental results, we confirmed that an ECT was possible to detect EDM slits 0.3 mm or more in depth and artificial SCC defects 0.02 mm to 0.48 mm in depth on machined surface. Furthermore, the underwater ECT defect detectability is equivalent to that in air. We clarified an ECT is sufficiently usable as a surface inspection technique for underwater laser beam welding works. (author)

Experimental Study on the Measurement of Water Bottom Vibration Induced by Underwater Drilling Blasting

OpenAIRE

Wenbin, Gu; Jianghai, Chen; Zhenxiong, Wang; Zhihua, Wang; Jianqing, Liu; Ming, Lu

2015-01-01

Due to the lack of proper instrumentations and the difficulties in underwater measurements, the studies about water bottom vibration induced by underwater drilling blasting are seldom reported. In order to investigate the propagation and attenuation laws of blasting induced water bottom vibration, a water bottom vibration monitor was developed with consideration of the difficulties in underwater measurements. By means of this equipment, the actual water bottom vibration induced by underwater ...

Bioterrorism: toxins as weapons.

Science.gov (United States)

Anderson, Peter D

2012-04-01

The potential for biological weapons to be used in terrorism is a real possibility. Biological weapons include infectious agents and toxins. Toxins are poisons produced by living organisms. Toxins relevant to bioterrorism include ricin, botulinum, Clostridium perfrigens epsilson toxin, conotoxins, shigatoxins, saxitoxins, tetrodotoxins, mycotoxins, and nicotine. Toxins have properties of biological and chemical weapons. Unlike pathogens, toxins do not produce an infection. Ricin causes multiorgan toxicity by blocking protein synthesis. Botulinum blocks acetylcholine in the peripheral nervous system leading to muscle paralysis. Epsilon toxin damages cell membranes. Conotoxins block potassium and sodium channels in neurons. Shigatoxins inhibit protein synthesis and induce apoptosis. Saxitoxin and tetrodotoxin inhibit sodium channels in neurons. Mycotoxins include aflatoxins and trichothecenes. Aflatoxins are carcinogens. Trichothecenes inhibit protein and nucleic acid synthesis. Nicotine produces numerous nicotinic effects in the nervous system.

Applicability evaluation of eddy current testing for underwater laser beam welding

International Nuclear Information System (INIS)

Kobayashi, Noriyasu; Kasuya, Takashi; Ueno, Souichi; Ochiai, Makoto; Yuguchi, Yasuhiro

2010-01-01

We clarified a defect detecting capability of eddy current testing (ECT) as a surface inspection technique for underwater laser beam welding. An underwater laser beam welding procedure includes groove caving as a preparation, laser beam welding in groove and welding surface grinding as a post treatment. Therefore groove and grinded welding surface inspections are required underwater. We curried out defect detection tests using three kinds of specimens simulated a groove, reactor vessel nozzle dissimilar metal welding materials and a laser beam welding material with a cross coil ECT probe. From experimental results, we confirmed that it is possible to detect 0.3 mm or more depth electro-discharge machining slits on machining surfaces in all specimens and an ECT has possibility as a surface inspection technique for underwater laser beam welding. (author)

A Survey of Routing Issues and Associated Protocols in Underwater Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Muhammad Khalid

2017-01-01

Full Text Available Underwater wireless sensor networks are a newly emerging wireless technology in which small size sensors with limited energy and limited memory and bandwidth are deployed in deep sea water and various monitoring operations like tactical surveillance, environmental monitoring, and data collection are performed through these tiny sensors. Underwater wireless sensor networks are used for the exploration of underwater resources, oceanographic data collection, flood or disaster prevention, tactical surveillance systems, and unmanned underwater vehicles. Sensor nodes consist of a small memory, a central processing unit, and an antenna. Underwater networks are much different from terrestrial sensor networks as radio waves cannot be used in underwater wireless sensor networks. Acoustic channels are used for communication in deep sea water. Acoustic signals have many limitations, such as limited bandwidth, higher end-to-end delay, network path loss, higher propagation delay, and dynamic topology. Usually, these limitations result in higher energy consumption with a smaller number of packets delivered. The main aim nowadays is to operate sensor nodes having a smaller battery for a longer time in the network. This survey has discussed the state-of-the-art localization based and localization-free routing protocols. Routing associated issues in the area of underwater wireless sensor networks have also been discussed.

Evaluation of Underwater Image Enhancement Algorithms under Different Environmental Conditions

Directory of Open Access Journals (Sweden)

Marino Mangeruga

2018-01-01

Full Text Available Underwater images usually suffer from poor visibility, lack of contrast and colour casting, mainly due to light absorption and scattering. In literature, there are many algorithms aimed to enhance the quality of underwater images through different approaches. Our purpose was to identify an algorithm that performs well in different environmental conditions. We have selected some algorithms from the state of the art and we have employed them to enhance a dataset of images produced in various underwater sites, representing different environmental and illumination conditions. These enhanced images have been evaluated through some quantitative metrics. By analysing the results of these metrics, we tried to understand which of the selected algorithms performed better than the others. Another purpose of our research was to establish if a quantitative metric was enough to judge the behaviour of an underwater image enhancement algorithm. We aim to demonstrate that, even if the metrics can provide an indicative estimation of image quality, they could lead to inconsistent or erroneous evaluations.

Weapons material and the commercial fuel cycle

International Nuclear Information System (INIS)

Steyn, J.J.

1993-01-01

In 1991, the United States and the former USSR had arsenals of ∼18,000 and 27,200 nuclear weapons, respectively. Approximately 10,000 of the US and 13,000 of the former USSR weapons were in the strategic category, and the remainder were tactical weapons. The dramatic changes in the political climate between the United States and the republics of the former USSR have resulted in the signing of the Strategic Arms Reduction Treaty (START I and II), agreements to substantially reduce nuclear weapons arsenals. Tactical weapons have already been collected in Russia, and strategic weapons are to be collected by the end of 1994. The major issues in accomplishing the treaty reductions appear to be funding, transport safety, storage capacity, and political issues between Russia and Ukraine because the latter seems to be using its weapons for political leverage on other matters. Collectively, the US and former USSR warhead stockpiles contain tremendous inventories of high-enriched uranium and weapons-grade plutonium which if converted to light water reactor fuel would equate to an enormous economic supply of natural uranium, conversion services, and enrichment separative work. The potential for this material entering the light water reactor fuel marketplace was enhanced in July 1992, when the two US industrial companies, Nuclear Fuel Services and Allied-Signal, announced that they had reached a preliminary agreement with the Russian ministry, Minatom, and the Russian Academay of Sciences to convert Russian high-enriched uranium to low-enriched uranium

Study on underwater plasma arc cutting technology

International Nuclear Information System (INIS)

Yada, Toshio; Nakamura, Uhachiro; Tomidokoro, Sakae; Fukuzawa, Mitsuo

1980-01-01

The zirconium alloy tube of the impile creep test facility had been subjected to inner pressure in the Japan Material Testing Reactor (JMTR) environment. In the near future, it will be necessary to dismantle the facility and to take out the tube for such examinations as irradiation effects on material properties. In order to establish the dismantling technology for the radioactive facility, a study on underwater plasma arc cutting has been carried out since 1977. Primarily, optimum underwater cutting sequence and conditions were studied in details for developing the remote control handling and the cutting system. Further, the amounts of particles suspended in water as well as those contained in bubbled gas were quantitatively analyzed for developing a safe removal system for contaminants which were produced by cutting the radioactive material. As a result of this study, it has been concluded that the underwater plasma arc cutting method is generally suitable and effective for dismantling such radioactive material as the impile creep test facility of the JMTR. (author)

Modeling and Control of Underwater Robotic Systems

Energy Technology Data Exchange (ETDEWEB)

Schjoelberg, I:

1996-12-31

This doctoral thesis describes modeling and control of underwater vehicle-manipulator systems. The thesis also presents a model and a control scheme for a system consisting of a surface vessel connected to an underwater robotic system by means of a slender marine structure. The equations of motion of the underwater vehicle and manipulator are described and the system kinematics and properties presented. Feedback linearization technique is applied to the system and evaluated through a simulation study. Passivity-based controllers for vehicle and manipulator control are presented. Stability of the closed loop system is proved and simulation results are given. The equation of motion for lateral motion of a cable/riser system connected to a surface vessel at the top end and to a thruster at the bottom end is described and stability analysis and simulations are presented. The equations of motion in 3 degrees of freedom of the cable/riser, surface vessel and robotic system are given. Stability analysis of the total system with PD-controllers is presented. 47 refs., 32 figs., 7 tabs.

Effects of Weapons on Aggressive Thoughts, Angry Feelings, Hostile Appraisals, and Aggressive Behavior: A Meta-Analytic Review of the Weapons Effect Literature.

Science.gov (United States)

Benjamin, Arlin J; Kepes, Sven; Bushman, Brad J

2017-09-01

Guns are associated with aggression. A landmark 1967 study showed that simply seeing a gun can increase aggression-called the "weapons effect." This meta-analysis integrates the findings of weapons effect studies conducted from 1967 to 2017. It includes 162 effect-size estimates from 78 independent studies involving 7,668 participants. The theoretical framework used to explain the weapons effect was the General Aggression Model (GAM), which proposes three routes to aggression-cognitive, affective, and arousal. The GAM also proposes that hostile appraisals can facilitate aggression. As predicted by the GAM, the mere presence of weapons increased aggressive thoughts, hostile appraisals, and aggression, suggesting a cognitive route from weapons to aggression. Weapons did not significantly increase angry feelings. Only one study tested the effects of weapons on arousal. These findings also contribute to the debate about social priming by showing that incidental exposure to a stimulus (weapon) can affect subsequent related behavior (aggression).

Characterising the online weapons trafficking on cryptomarkets.

Science.gov (United States)

Rhumorbarbe, Damien; Werner, Denis; Gilliéron, Quentin; Staehli, Ludovic; Broséus, Julian; Rossy, Quentin

2018-02-01

Weapons related webpages from nine cryptomarkets were manually duplicated in February 2016. Information about the listings (i.e. sales proposals) and vendors' profiles were extracted to draw an overview of the actual online trafficking of weapons. Relationships between vendors were also inferred through the analysis of online digital traces and content similarities. Weapons trafficking is mainly concentrated on two major cryptomarkets. Besides, it accounts for a very small proportion of the illicit trafficking on cryptomarkets compared to the illicit drugs trafficking. Among all weapon related listings (n=386), firearms only account for approximately 25% of sales proposal since the proportion of non-lethal and melee weapons is important (around 46%). Based on the recorded pseudonyms, a total of 96 vendor profiles were highlighted. Some pseudonyms were encountered on several cryptomarkets, suggesting that some vendors may manage accounts on different markets. This hypothesis was strengthened by comparing pseudonyms to online traces such as PGP keys, images and profiles descriptions. Such a method allowed to estimate more accurately the number of vendors offering weapons across cryptomarkets. Finally, according to the gathered data, the extent of the weapons trafficking on the cryptomarkets appear to be limited compared to other illicit goods. Copyright © 2017 Elsevier B.V. All rights reserved.

Hydrodynamic design of an underwater hull cleaning robot and its evaluation

Directory of Open Access Journals (Sweden)

Man Hyung Lee

2012-12-01

Full Text Available An underwater hull cleaning robot can be a desirable choice for the cleaning of large ships. It can make the cleaning process safe and economical. This paper presents a hydrodynamic design of an underwater cleaning robot and its evaluation for an underwater ship hull cleaning robot. The hydrodynamic design process of the robot body is described in detail. Optimal body design process with compromises among conflicting design requirements is given. Experimental results on the hydrodynamic performance of the robot are given.

Monterey Bay ambient noise profiles using underwater gliders

OpenAIRE

Chandrayadula, Tarun K.; Miller, Chris W.; Joseph, John

2013-01-01

The article of record as published may be found at http://dx.doi.org/10.1121/1.4799131 In 2012, during two separate week-long deployments, underwater gliders outfitted with external hydrophones profiled the upper 100-200 m of the Monterey Bay. The environment contained various noises made by marine mammals, ships, winds, and earthquakes. Unlike hydrophone receivers moored to a fixed location, moving gliders measure noise variability across a wide terrain. However, underwater mobile s...

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization

Directory of Open Access Journals (Sweden)

Nasir Saeed

2017-12-01

Full Text Available Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB is derived for localization accuracy of the proposed technique.

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization.

Science.gov (United States)

Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y; Alouini, Mohamed-Slim

2017-12-26

Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs) is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS) based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB) is derived for localization accuracy of the proposed technique.

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization

KAUST Repository

Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

2017-01-01

Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs) is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS) based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB) is derived for localization accuracy of the proposed technique.

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization

KAUST Repository

Saeed, Nasir

2017-12-26

Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs) is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS) based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB) is derived for localization accuracy of the proposed technique.

Cutting method and device underwater

International Nuclear Information System (INIS)

Takano, Genta; Kamei, Hiromasa; Beppu, Seiji

1998-01-01

A place of material to be cut is surrounded by an openable/closable box. The material to be cut is cut underwater, and materials generated in this case are removed from the cut portion by a pressurized water jet. The removed materials are sucked and recovered together with water in the box. Among the materials caused by the cutting underwater, solid materials not floating on water are caused to stay in the midway of a sucking and recovering channel. A large sucking force might be required for the entire region of the sucking and recovering channel when sucking and recovering large sized solid materials not floating on water, but even large sized materials can be recovered easily according to the present invention since they are recovered after being sucked and stayed in the midway of the sucking and recovering channel. (N.H.)

Underwater Optical Wireless Communications, Networking, and Localization: A Survey

KAUST Repository

Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

2018-01-01

Underwater wireless communications can be carried out through acoustic, radio frequency (RF), and optical waves. Compared to its bandwidth limited acoustic and RF counterparts, underwater optical wireless communications (UOWCs) can support higher data rates at low latency levels. However, severe aquatic channel conditions (e.g., absorption, scattering, turbulence, etc.) pose great challenges for UOWCs and significantly reduce the attainable communication ranges, which necessitates efficient networking and localization solutions. Therefore, we provide a comprehensive survey on the challenges, advances, and prospects of underwater optical wireless networks (UOWNs) from a layer by layer perspective which includes: 1) Potential network architectures; 2) Physical layer issues including propagation characteristics, channel modeling, and modulation techniques 3) Data link layer problems covering link configurations, link budgets, performance metrics, and multiple access schemes; 4) Network layer topics containing relaying techniques and potential routing algorithms; 5) Transport layer subjects such as connectivity, reliability, flow and congestion control; 6) Application layer goals and state-of-the-art UOWN applications, and 7) Localization and its impacts on UOWN layers. Finally, we outline the open research challenges and point out the future directions for underwater optical wireless communications, networking, and localization research.

Underwater Optical Wireless Communications, Networking, and Localization: A Survey

KAUST Repository

Saeed, Nasir

2018-02-28

Underwater wireless communications can be carried out through acoustic, radio frequency (RF), and optical waves. Compared to its bandwidth limited acoustic and RF counterparts, underwater optical wireless communications (UOWCs) can support higher data rates at low latency levels. However, severe aquatic channel conditions (e.g., absorption, scattering, turbulence, etc.) pose great challenges for UOWCs and significantly reduce the attainable communication ranges, which necessitates efficient networking and localization solutions. Therefore, we provide a comprehensive survey on the challenges, advances, and prospects of underwater optical wireless networks (UOWNs) from a layer by layer perspective which includes: 1) Potential network architectures; 2) Physical layer issues including propagation characteristics, channel modeling, and modulation techniques 3) Data link layer problems covering link configurations, link budgets, performance metrics, and multiple access schemes; 4) Network layer topics containing relaying techniques and potential routing algorithms; 5) Transport layer subjects such as connectivity, reliability, flow and congestion control; 6) Application layer goals and state-of-the-art UOWN applications, and 7) Localization and its impacts on UOWN layers. Finally, we outline the open research challenges and point out the future directions for underwater optical wireless communications, networking, and localization research.

Precursor of other nuclear-weapon-free zones

International Nuclear Information System (INIS)

Roman-Morey, E.

1997-01-01

Based on the analysis of the long process of negotiations for implementing the Treaty of Tlatelolco and its history during the last three decades, especially its influence on other regions of the world for stimulating the creation of new nuclear-weapon-free zones, the following conclusions were drawn: nuclear danger still persists; the end of Cold War implies the end of a nuclear threat; the nuclear fear should not become nuclear complacency and be accepted by international community; common security as the goal of international community should be recognised and definitive abolition of nuclear weapons should be sought; the Treaty of Tlatelolco represents the cornerstone for creating new nuclear-weapon-free zones; Treaties of Tlatelolco, Rarotonga, Bangkok and Pelindaba should be examples to be followed by other regions and groups of countries for creating new nuclear-weapon-free zones which should be recognised as very important phase in achieving a nuclear-weapon-free world and means for attaining an international regime of non-proliferation of weapons for mass destruction

A thermal engine for underwater glider driven by ocean thermal energy

International Nuclear Information System (INIS)

Yang, Yanan; Wang, Yanhui; Ma, Zhesong; Wang, Shuxin

2016-01-01

Highlights: • Thermal engine with a double-tube structure is developed for underwater glider. • Isostatic pressing technology is effective to increase volumetric change rate. • Actual volumetric change rate reaches 89.2% of the theoretical value. • Long term sailing of 677 km and 27 days is achieved by thermal underwater glider. - Graphical Abstract: - Abstract: Underwater glider is one of the most popular platforms for long term ocean observation. Underwater glider driven by ocean thermal energy extends the duration and range of underwater glider powered by battery. Thermal engine is the core device of underwater glider to harvest ocean thermal energy. In this paper, (1) model of thermal engine was raised by thermodynamics method and the performance of thermal engine was investigated, (2) thermal engine with a double-tube structure was developed and isostatic pressing technology was applied to improve the performance for buoyancy driven, referencing powder pressing theory, (3) wall thickness of thermal engine was optimized to reduce the overall weight of thermal engine, (4) material selection and dimension determination were discussed for a faster heat transfer design, by thermal resistance analysis, (5) laboratory test and long term sea trail were carried out to test the performance of thermal engine. The study shows that volumetric change rate is the most important indicator to evaluating buoyancy-driven performance of a thermal engine, isostatic pressing technology is effective to improve volumetric change rate, actual volumetric change rate can reach 89.2% of the theoretical value and the average power is about 124 W in a typical diving profile. Thermal engine developed by Tianjin University is a superior thermal energy conversion device for underwater glider. Additionally, application of thermal engine provides a new solution for miniaturization of ocean thermal energy conversion.

Summary of the guideline on underwater laser beam repair welding

International Nuclear Information System (INIS)

Ichikawa, Hiroya; Yoda, Masaki; Motora, Yuichi

2013-01-01

It is known that stress corrosion cracking (SCC) might occur at the weld of a reactor pressure vessel or core internals. Underwater laser beam clad welding for mitigation of SCC has been already established and the guideline 'Underwater laser beam clad welding' was published. Moreover, the guideline 'Seal welding' was also published as a repair method for SCC. In addition to these guidelines, the guideline 'Underwater laser beam repair welding' was newly published in November, 2012 for the repair welding after completely removing a SCC crack occurred in weld or base metal. This paper introduces the summary of this guideline. (author)

ROV-based Underwater Vision System for Intelligent Fish Ethology Research

Directory of Open Access Journals (Sweden)

Rui Nian

2013-09-01

Full Text Available Fish ethology is a prospective discipline for ocean surveys. In this paper, one ROV-based system is established to perform underwater visual tasks with customized optical sensors installed. One image quality enhancement method is first presented in the context of creating underwater imaging models combined with homomorphic filtering and wavelet decomposition. The underwater vision system can further detect and track swimming fish from the resulting images with the strategies developed using curve evolution and particular filtering, in order to obtain a deeper understanding of fish behaviours. The simulation results have shown the excellent performance of the developed scheme, in regard to both robustness and effectiveness.

Application of YAG laser processing in underwater welding and cutting

Energy Technology Data Exchange (ETDEWEB)

Ohwaki, Katsura; Morita, Ichiro; Kojima, Toshio; Sato, Shuichi [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

2002-09-01

The high-power YAG laser is a new fabrication tool. The laser torch is easy to combine with complex with complex mechanics because of beam delivery through optical fiber. A direct underwater laser welding technology has been developed and applied to the preservation, maintenance and removal of nuclear power plants. For subdividing or removing operations for retirement of plants, the laser cutting properties were confirmed to allow a maximum cutting thickness of 80 mm. For repairing inner surface of stainless steel tanks, an underwater laser welding system using a remote-controlled robot was developed and the high quality of underwater laser welding was confirmed. (author)

Rays as weapons

International Nuclear Information System (INIS)

Vogel, H.

2007-01-01

Purpose: Ionizing radiation is being regarded as life threatening. Therefore, accidents in nuclear power plants are considered equal threatening as nuclear bomb explosions, and attacks with dirty bombs are thought as dangerous as nuclear weapon explosions. However, there are differences between a nuclear bomb explosion, the largest imaginable accident in a nuclear power plant, and an attack with a dirty bomb. It is intended to point them out. Method: The processes are described, which damage in a nuclear bomb explosion, in the largest imaginable accident in a nuclear power plant, and in an attack with a dirty bomb. Their effects are compared with each other, i.e. explosion, heat, shock wave (blast), ionizing radiation, and fallout. Results: In the center of the explosion of a nuclear bomb, the temperature rises to 100 Mio deg.C, this induces damaging heat radiation and shock wave. In the largest imaginable accident in a nuclear power plant and in the conventional explosion of a dirty bomb, the temperature may rise up to 3000 deg. C, heat radiation and blast are limited to a short distance. In nuclear power plants, explosions due to oxyhydrogen gas or steam may occur. In nuclear explosions the dispersed radioactive material (fall out) consists mainly of isotopes with short half-life, in nuclear power plants and in dirty bomb attacks with longer half-life. The amount of fall out is comparable in nuclear bomb explosions with that in the largest imaginable accident in a nuclear power plant, it is smaller in attacks with dirty bombs. An explosion in a nuclear power plant even in the largest imaginable accident is not a nuclear explosion. In Hiroshima and Nagasaki, there were 200,000 victims nearly all by heat and blast, some 300 died by ionizing radiation. In Chernobyl, there have been less than 100 victims due to ionizing radiation up till now. A dirty bomb kills possibly with the explosion of conventional explosive, the dispersed radioactive material may damage

China's mixed signals on nuclear weapons

International Nuclear Information System (INIS)

Fieldhouse, R.

1991-01-01

Ultimately, it is nuclear whether the Chinese leadership has made up its collective mind on practical nuclear weapons. It is known from Chinese official sources, including articles in Communist Party and military publications and histories of the Chinese nuclear program, that an internal debate has proceeded for more than two decades, punctuated by occasional nuclear exercises or low-yield warhead tests. But China presumably has less reason now to pursue development of tactical nuclear weapons than in previous decades: relations with the Soviet Union have improved and military confrontation has eased; China's relations with India and Vietnam are also improving. The decision may already have been made, however, and the weapons built. The mystery surrounding Chinese tactical nuclear weapons is itself interesting, but it is also symbolic of the difficulty of understanding China's nuclear weapons program and policies. The West has accumulated a considerable body of knowledge about China's nuclear forces, especially historical material. But important aspects of China's nuclear behavior and its future as a nuclear power are hard to discern. A key question is China's future role in the spread of nuclear-capable weapons to other countries. China might add to international efforts to stem the proliferation of nuclear related technology, or it might become the world's missile merchant. It could make a constructive contribution to arms control efforts in general, or it could act as a spoiler

Small Arms - Hand and Shoulder Weapons and Machine Guns

Science.gov (United States)

2016-06-24

weapon barrels between firing trials is permitted. A locally fabricated rack can be used for barrels that are detached from the weapon; the air should...Lubricating oil, weapons MIL-L-14107 (LAW) 19. Hydraulic fluid, petroleum base MIL-H-5606 20. Hydraulic fluid, fire - resistant MIL-H-46170...weapon from the test environment to perform maintenance. 4.20.8 Smoke . a. Background. The smoke cloud accumulated during weapon firing can

The Regulation of the Possession of Weapons at Gatherings

Directory of Open Access Journals (Sweden)

Pieter du Toit

2013-12-01

Full Text Available The Dangerous Weapons Act 15 of 2013 provides for certain prohibitions and restrictions in respect of the possession of a dangerous weapon and it repeals the Dangerous Weapons Act 71 of 1968 as well as the different Dangerous Weapons Acts in operation in the erstwhile TBVC States. The Act also amends the Regulation of Gatherings Act 205 of 1993 to prohibit the possession of any dangerous weapon at a gathering or demonstration. The Dangerous Weapons Act provides for a uniform system of law governing the use of dangerous weapons for the whole of South Africa and it furthermore no longer places the onus on the individual charged with the offence of the possession of a dangerous weapon to show that he or she did not have any intention of using the firearm for an unlawful purpose. The Act also defines the meaning of a dangerous weapon. According to our court’s interpretation of the Dangerous Weapons Act 71 of 1968 a dangerous weapon was regarded as an object used or intended to be used as a weapon even if it had not been designed for use as a weapon. The Act, however, requires the object to be capable of causing death or inflicting serious bodily harm if it were used for an unlawful purpose. The possession of a dangerous weapon, in circumstances which may raise a reasonable suspicion that the person intends to use it for an unlawful purpose, attracts criminal liability. The Act also provides a useful set of guidelines to assist courts to determine if a person charged with the offence of the possession of a dangerous weapon had indeed intended to use the weapon for an unlawful purpose. It seems, however, that the Act prohibits the possession of a dangerous weapon at gatherings, even if the person carrying the weapon does not intend to use it for an unlawful purpose. The state will, however, have to prove that the accused had the necessary control over the object and the intention to exercise such control, as well as that the object is capable of

Optimum LED wavelength for underwater optical wireless communication at turbid water

Science.gov (United States)

Rosenkrantz, Etai; Arnon, Shlomi

2014-10-01

Underwater optical wireless communication is an emerging technology, which can provide high data rate. High data rate communication is required for applications such as underwater imaging, networks of sensors and swarms of underwater vehicles. These applications pursue an affordable light source, which can be obtained by light emitting diodes (LED). LEDs offer solutions characterized by low cost, high efficiency, reliability and compactness based on off-the-shelf components such as blue and green light emitting diodes. In this paper we present our recent theoretical and experimental results in this field.

New Weapons and the Arms Race

Science.gov (United States)

Tsipis, Kosta

1983-10-01

In speaking about technologies that could further animate the weapons competition between the United States and the U.S.S.R., it would be useful to distinguish between technologies that have already been incorporated into specific weapons systems, and new technologies that are of a generic nature, can be used in a variety of applications, adn can best be described by the tasks that they can perform rather than any specific weapons application. Let me begin with the latter class.

Underwater videography and photography in Gulf of Kachchh. Sponsored by Gujarat Ecological Society, Vadodara, Gujarat

Digital Repository Service at National Institute of Oceanography (India)

Marine Archaeology Centre (MAC) has been carrying out underwater explorations and excavations of ancient ports and sunken shipwrecks to preserve underwater cultural heritage. MAC has the infrastructure facility to carry out underwater investigations...

Underwater nuclear power plant structure

International Nuclear Information System (INIS)

Severs, S.; Toll, H.V.

1982-01-01

A structure for an underwater nuclear power generating plant comprising a triangular platform formed of tubular leg and truss members upon which are attached one or more large spherical pressure vessels and one or more small cylindrical auxiliary pressure vessels. (author)

Analysing deterioration of marble stones exposed to underwater conditions

Science.gov (United States)

Cámara, Beatriz; Álvarez de Buergo, Mónica; Bethencourt, Manuel; Freire-Lista, David; Fort, Rafael

2016-04-01

The peculiar conditions of the marine environment make the conservation of underwater archaeological sites an extremely complex procedure. This is due to the fact that the prevailing conditions in this environment promote the development of deterioration phenomena in submerged artefacts through the synergistic action of physical, chemical and biological factors. The objective of the present investigation was to determine how petrophysical properties of cultural heritage materials can be affected by being exposed to the specific underwater conditions of the sea bottom, and so, to evaluate how this can affect, in a long term, in their durability and evolution when they part of an archaeological site. For this purpose, two types of marble (the Italian Carrara and the Spanish Macael) were subjected to an experiment consisting of exposing stone materials for one and a half year to underwater conditions. The experimental test was located in an archaeological site in the Bay of Cadiz (southern Spain), Bajo del Chapitel (recognized as Cultural Interest), which includes remains of shipwrecks from different periods. In this site, samples were submerged to 12 m depth and placed in the sea bottom simulating the different positions in which underwater archaeological objects can be found (fully exposed, half buried and covered). Petrophysical characterisation involved determination of the apparent and bulk densities, water saturation (maximum water content a material may contain), open porosity (porosity accessible to water), chromatic parameters and ultrasonic velocity. Before measuring, samples were subjected to mechanical cleaning (in those samples with biological colonization) and to removal of salt deposits. Results showed significant differences in these petrophysical properties after underwater submersion, which were directly related to the type of underwater exposure condition. Comparative analysis of petrophysical properties, like the one conducted in this study

FILMING UNDERWATER IN 3D RESPECTING STEREOGRAPHIC RULES

OpenAIRE

R. Rinaldi; H. Hordosch

2015-01-01

After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space ("Gravity") and the underwater realm look perfect to be reproduced in 3D. "Filming in space" was possible in "Gravity" using special effects and computer graphic. The underwater realm is still difficult to be handled. Under...

The real value of nuclear-weapon-free zones

International Nuclear Information System (INIS)

Carasales, J.

1998-01-01

The international community has greeted the establishment of two new nuclear weapon-free zones with praise. Africa and South Asia are the regions which will join, once the respective treaties are ratified and in force, Latin America and the South Pacific to ensure that extensive areas of the earth remain free of nuclear weapons. The usual reaction to these accomplishments is to hail them as important contributions to international peace and security, and as meaningful steps towards a world free of nuclear weapons. The nuclear weapon-free zones have their value but this value relates mainly to the countries within the zone. The interest of nuclear-weapon states are not really affected, or, if they are, the influence is not significant. One should bear in mind that the really important and meaningful nuclear weapon-free zones have yet to be achieved

Development of underwater and hyperbaric medicine in Malaysia.

Science.gov (United States)

Rozali, A; Rampal, K G; Zin, B Mohd; Sherina, M S; Khairuddin, H; Abd Halim, M; Sulaiman, A

2006-12-01

Underwater and Hyperbaric Medicine is a treatment modality gaining recognition in Malaysia. It uses the hyperbaric oxygen therapy (HBOT) approach where patients are placed in recompression chambers and subjected to oxygen therapy under pressure. In Malaysia it was introduced as early as the 1960's by the Royal Malaysian Navy to treat their divers for decompression illness (DCI), arterial gas embolism (AGE) and barotraumas. Other sectors in the armed forces, universities and private health centres began developing this approach too in the late 1990's, for similar purposes. In 1996, Underwater and Hyperbaric Medicine began gaining its popularity when the Institute of Underwater and Hyperbaric Medicine at the Armed Forces Hospital in Lumut started treating specific clinical diseases such as diabetic foot ulcers, osteomyelitis, and carbon monoxide poisoning and other diseases using HBOT. This paper discusses the development of this interesting treatment modality, giving a brief historical overview to its current development, as well as provides some thought for its future development in Malaysia.

Optimal Node Placement in Underwater Wireless Sensor Networks

KAUST Repository

Felamban, M.

2013-03-25

Wireless Sensor Networks (WSN) are expected to play a vital role in the exploration and monitoring of underwater areas which are not easily reachable by humans. However, underwater communication via acoustic waves is subject to several performance limitations that are very different from those used for terresstrial networks. In this paper, we investigate node placement for building an initial underwater WSN infrastructure. We formulate this problem as a nonlinear mathematical program with the objective of minimizing the total transmission loss under a given number of sensor nodes and targeted coverage volume. The obtained solution is the location of each node represented via a truncated octahedron to fill out the 3D space. Experiments are conducted to verify the proposed formulation, which is solved using Matlab optimization tool. Simulation is also conducted using an ns-3 simulator, and the simulation results are consistent with the obtained results from mathematical model with less than 10% error.

Actuated Recoil Absorbing Mounting System for use with an Underwater Gun

Science.gov (United States)

1998-03-31

fire supercavitating bullets, requires that 20 the new projectile launchers be tested. The firing of projectile 21 launchers involving a high...of projectile launcher 12 includes an underwater gun 15 that fires supercavitating bullets underwater and has a high 16 discharge energy. However

Strong underwater adhesives made by self-assembling multi-protein nanofibres.

Science.gov (United States)

Zhong, Chao; Gurry, Thomas; Cheng, Allen A; Downey, Jordan; Deng, Zhengtao; Stultz, Collin M; Lu, Timothy K

2014-10-01

Many natural underwater adhesives harness hierarchically assembled amyloid nanostructures to achieve strong and robust interfacial adhesion under dynamic and turbulent environments. Despite recent advances, our understanding of the molecular design, self-assembly and structure-function relationships of these natural amyloid fibres remains limited. Thus, designing biomimetic amyloid-based adhesives remains challenging. Here, we report strong and multi-functional underwater adhesives obtained from fusing mussel foot proteins (Mfps) of Mytilus galloprovincialis with CsgA proteins, the major subunit of Escherichia coli amyloid curli fibres. These hybrid molecular materials hierarchically self-assemble into higher-order structures, in which, according to molecular dynamics simulations, disordered adhesive Mfp domains are exposed on the exterior of amyloid cores formed by CsgA. Our fibres have an underwater adhesion energy approaching 20.9 mJ m(-2), which is 1.5 times greater than the maximum of bio-inspired and bio-derived protein-based underwater adhesives reported thus far. Moreover, they outperform Mfps or curli fibres taken on their own and exhibit better tolerance to auto-oxidation than Mfps at pH ≥ 7.0.

Nuclear Weapons in Russia's approach to conflict

International Nuclear Information System (INIS)

Johnson, Dave

2016-11-01

President Putin has moved nuclear weapons to the foreground of the European security landscape. New risks and dangers arise from the apparent coupling of nuclear weapons capabilities with Moscow's revanchist and irredentist foreign and defence policies toward its neighbours. Nuclear weapons are the central feature and capstone capability in Russia's evolving concept of strategic deterrence and are important tools for achieving Russia's geopolitical aims. Russian thinking on the role and place of nuclear weapons in upholding national security and in achieving strategic aims is reflected in military policy, force structure and posture, and exercises and operations. Russia's political and military leaders are not only re-conceptualising the role of nuclear weapons. They are also building the military capabilities that can credibly threaten the calibrated employment of nuclear weapons for deterrence, de-escalation and war-fighting from the regional to large-scale and global levels of conflict. New and still developing concepts for the employment of conventional long-range precision weapons in tandem with nuclear weapons for regional deterrence and containment of local and regional conflicts add volatility to the regional tensions and uncertainties created by recent Russian aggression. Russia's reliance upon integrated conventional and nuclear capabilities in reasserting its influence in its perceived sphere of special interest, intended to contain conflicts at a manageable level, could actually increase the risk of the potential employment of nuclear weapons. NATO nations collectively, and the three NATO nuclear powers (Great Britain, France, and the United States) individually, have recognized this new reality and have begun to adapt to it. In that context, the aim of this paper is to elaborate a clearer understanding of the place and role of nuclear weapons in Russia's approach to conflict, based on nuclear-related policy statements and military-theoretical writing

On the Performance of the Underwater Acoustic Sensor Networks

Science.gov (United States)

2015-05-01

performance of UWSN. 5.1 Hardware and Software Details 5.1.1 Equipment Our experimental model consisted of an indoor swimming pool , two pairs...UWSN has many constraints mainly due to limited capacity, propagation loss, as well as power limitation since in underwater environment solar energy ...since in underwater environment solar energy cannot be used to recharge batteries. In our approach, we estimate the number of operating receivers

A novel underwater dam crack detection and classification approach based on sonar images.

Science.gov (United States)

Shi, Pengfei; Fan, Xinnan; Ni, Jianjun; Khan, Zubair; Li, Min

2017-01-01

Underwater dam crack detection and classification based on sonar images is a challenging task because underwater environments are complex and because cracks are quite random and diverse in nature. Furthermore, obtainable sonar images are of low resolution. To address these problems, a novel underwater dam crack detection and classification approach based on sonar imagery is proposed. First, the sonar images are divided into image blocks. Second, a clustering analysis of a 3-D feature space is used to obtain the crack fragments. Third, the crack fragments are connected using an improved tensor voting method. Fourth, a minimum spanning tree is used to obtain the crack curve. Finally, an improved evidence theory combined with fuzzy rule reasoning is proposed to classify the cracks. Experimental results show that the proposed approach is able to detect underwater dam cracks and classify them accurately and effectively under complex underwater environments.

A novel underwater dam crack detection and classification approach based on sonar images.

Directory of Open Access Journals (Sweden)

Pengfei Shi

Full Text Available Underwater dam crack detection and classification based on sonar images is a challenging task because underwater environments are complex and because cracks are quite random and diverse in nature. Furthermore, obtainable sonar images are of low resolution. To address these problems, a novel underwater dam crack detection and classification approach based on sonar imagery is proposed. First, the sonar images are divided into image blocks. Second, a clustering analysis of a 3-D feature space is used to obtain the crack fragments. Third, the crack fragments are connected using an improved tensor voting method. Fourth, a minimum spanning tree is used to obtain the crack curve. Finally, an improved evidence theory combined with fuzzy rule reasoning is proposed to classify the cracks. Experimental results show that the proposed approach is able to detect underwater dam cracks and classify them accurately and effectively under complex underwater environments.

Overall view of chemical and biochemical weapons.

Science.gov (United States)

Pitschmann, Vladimír

2014-06-04

This article describes a brief history of chemical warfare, which culminated in the signing of the Chemical Weapons Convention. It describes the current level of chemical weapons and the risk of using them. Furthermore, some traditional technology for the development of chemical weapons, such as increasing toxicity, methods of overcoming chemical protection, research on natural toxins or the introduction of binary technology, has been described. In accordance with many parameters, chemical weapons based on traditional technologies have achieved the limit of their development. There is, however, a big potential of their further development based on the most recent knowledge of modern scientific and technical disciplines, particularly at the boundary of chemistry and biology. The risk is even higher due to the fact that already, today, there is a general acceptance of the development of non-lethal chemical weapons at a technologically higher level. In the future, the chemical arsenal will be based on the accumulation of important information from the fields of chemical, biological and toxin weapons. Data banks obtained in this way will be hardly accessible and the risk of their materialization will persist.

Overall View of Chemical and Biochemical Weapons

Directory of Open Access Journals (Sweden)

Vladimír Pitschmann

2014-06-01

Full Text Available This article describes a brief history of chemical warfare, which culminated in the signing of the Chemical Weapons Convention. It describes the current level of chemical weapons and the risk of using them. Furthermore, some traditional technology for the development of chemical weapons, such as increasing toxicity, methods of overcoming chemical protection, research on natural toxins or the introduction of binary technology, has been described. In accordance with many parameters, chemical weapons based on traditional technologies have achieved the limit of their development. There is, however, a big potential of their further development based on the most recent knowledge of modern scientific and technical disciplines, particularly at the boundary of chemistry and biology. The risk is even higher due to the fact that already, today, there is a general acceptance of the development of non-lethal chemical weapons at a technologically higher level. In the future, the chemical arsenal will be based on the accumulation of important information from the fields of chemical, biological and toxin weapons. Data banks obtained in this way will be hardly accessible and the risk of their materialization will persist.

Underwater electric field detection system based on weakly electric fish

Science.gov (United States)

Xue, Wei; Wang, Tianyu; Wang, Qi

2018-04-01

Weakly electric fish sense their surroundings in complete darkness by their active electric field detection system. However, due to the insufficient detection capacity of the electric field, the detection distance is not enough, and the detection accuracy is not high. In this paper, a method of underwater detection based on rotating current field theory is proposed to improve the performance of underwater electric field detection system. First of all, we built underwater detection system based on the theory of the spin current field mathematical model with the help of the results of previous researchers. Then we completed the principle prototype and finished the metal objects in the water environment detection experiments, laid the foundation for the further experiments.

Airborne lidar detection of an underwater thermal vent

Science.gov (United States)

Roddewig, Michael R.; Churnside, James H.; Shaw, Joseph A.

2017-07-01

We report the lidar detection of an underwater feature that appears to be a thermal vent in Yellowstone Lake, Yellowstone National Park, USA, with the Montana State University Fish Lidar. The location of the detected vent was 30 m from the closest vent identified in a United States Geological Survey of Yellowstone Lake in 2008. A second possible vent is also presented, and the appearance of both vents in the lidar data is compared to descriptions of underwater thermal vents in Yellowstone Lake from the geological literature.

Underwater Shock Response Analysis of a Floating Vessel

Directory of Open Access Journals (Sweden)

J.E. van Aanhold

1998-01-01

Full Text Available The response of a surface vessel to underwater shock has been calculated using an explicit finite element analysis. The analysis model is two-dimensional and contains the floating steel structure, a large surrounding water volume and the free surface. The underwater shock is applied in the form of a plane shock wave and cavitation is considered in the analysis. Advanced computer graphics, in particular video animations, provide a powerful and indispensable means for the presentation and evaluation of the analysis results.

Reconstruction Accuracy Assessment of Surface and Underwater 3D Motion Analysis: A New Approach

Directory of Open Access Journals (Sweden)

Kelly de Jesus

2015-01-01

Full Text Available This study assessed accuracy of surface and underwater 3D reconstruction of a calibration volume with and without homography. A calibration volume (6000 × 2000 × 2500 mm with 236 markers (64 above and 88 underwater control points—with 8 common points at water surface—and 92 validation points was positioned on a 25 m swimming pool and recorded with two surface and four underwater cameras. Planar homography estimation for each calibration plane was computed to perform image rectification. Direct linear transformation algorithm for 3D reconstruction was applied, using 1600000 different combinations of 32 and 44 points out of the 64 and 88 control points for surface and underwater markers (resp.. Root Mean Square (RMS error with homography of control and validations points was lower than without it for surface and underwater cameras (P≤0.03. With homography, RMS errors of control and validation points were similar between surface and underwater cameras (P≥0.47. Without homography, RMS error of control points was greater for underwater than surface cameras (P≤0.04 and the opposite was observed for validation points (P≤0.04. It is recommended that future studies using 3D reconstruction should include homography to improve swimming movement analysis accuracy.

Issues of weapons of mass destruction non-proliferation in Tajikistan

International Nuclear Information System (INIS)

Mirsaidov, U.M.

2010-01-01

This article is devoted to issues of weapons of mass destruction non-proliferation in Tajikistan. Over a period of 20 century, starting from First World War, the weapons of mass destruction arouse serious concern of world community. Geneva protocol of 1925 prohibits the use of chemical and biological weapons. Once nuclear weapon was created, the weapons of mass destruction distributions become the subject of high concern. Besides, during the end of 'cold war', regional conflicts, collapse of Soviet Union, as well as access to sensitive technologies considerably increase the danger of weapons of mass destruction distribution. More than 10 countries have active programs, relating to weapons of mass destruction and, possibly, more than ten countries have potential to start implementing such kinds of programs. Nowadays, trans national organized criminal groups and international terrorist networks are appeared in the world scene, which show interest in obtaining an access to sensitive materials, technologies, weapons and their distribution. After 11 September events, the risk of such weapons of mass destruction components use by such forces for Governments blackmail become real scene, which, despite of low possibility of this threat implementation, could have very serious and disastrous consequences. International community responded to these problems and challenges, basically through the following actions, which is detailed regime development of multilateral international treaties, directed to weapons of mass destruction distribution prevention. Non-proliferation treaty of nuclear weapons, Convention on prohibition of chemical weapons and Convention on prohibition of biological and toxin weapons are some of them. As it is known, Tajikistan signed all these treaties. For different reasons these treaties were subject of serious tests. Nuclear weapons tests in India and Pakistan in 1998 year, actual Israel status as state having nuclear weapon and North Korean program on

An energy-harvesting power supply for underwater bridge scour monitoring sensors

Science.gov (United States)

Wang, Yuli; Li, Yingjie; He, Longzhuang; Shamsi, Pourya; Zheng, Yahong R.

2018-03-01

The natural force of scouring has become one of the most critical risk endangering the endurance of bridges, thus leading to the necessity of deploying underwater monitoring sensors to actively detect potential scour holes under bridges. Due to the difficulty in re-charging batteries for underwater sensors, super capacitors with energy harvesting (EH) means are exploited to prolong the sustainability of underwater sensors. In this paper, an energy harvesting power supply based on a helical turbine is proposed to power underwater monitoring sensors. A small helical turbine is designed to convert water flow energy to electrical energy with favorable environmental robustness. A 3-inch diameter, 2.5-inch length and 3-bladed helical turbine was designed with two types of waterproof coupling with the sensor housing. Both designs were prototyped and tested under different flow conditions and we get valid voltage around 0.91 V which is enough to power monitoring sensor. The alternating current (AC) electrical energy generated by the helical turbine is then rectified and boosted to drive a DC charger for efficiently charging one super capacitor. The charging circuit was designed, prototyped and tested thoroughly with the helical turbine harvester. The results were promising, that the overall power supply can power an underwater sensor node with wireless transceivers for long-term operations

The Basic Research for Pulverization of Rice Using Underwater Shock Wave by Electric Discharge

Directory of Open Access Journals (Sweden)

M Ide

2016-09-01

Full Text Available In recent years, the food self-support rate of Japan is 40%, and this value is the lowest level in major developed countries. This reason includes decreasing of diverting rice consumption in Japan and increasing abandonment of cultivation. Therefore, these problems are solved by using rice powder instead of expensive flour, and we manage to increase the food selfsupport rate. Previously, the rice powder is manufactured by two methods. One is dry type, and the other is wet type. The former is the method getting rice powder by running dried rice to rotating metal, and has a problem which that starch is damaged by heat when processing was performed. The latter is performed same method against wet rice, and has a problem which a large quantity of water is used. As a method to solve these problems, an underwater shock wave is used. Shock wave is the pressure wave which is over speed of sound by discharging high energy in short time. Propagating shock wave in water is underwater shock wave. The characters of underwater shock wave are long duration of shock wave because water density is uniform, water is low price and easy to get and not heat processing. Thinking of industrialization, the electric discharge is used as the generating source of underwater shock wave in the experiment. As the results, the efficiency of obtaining enough grain size, 100ìm, of rice powder was too bad only using the simple processing using underwater shock wave. Therefore, in Okinawa National College of Technology collaborating with us, obtaining rice powder with higher efficiency by using converged underwater shock wave is the goal of this research. In this research, the underwater shock wave with equal energy of the experimental device of underwater shock wave is measured by the optical observation. In addition, the appearance converging underwater shock wave is simulated by numerical analysis, and the pressure appreciation rate between the first wave and converged

Padus, Sandalus, Gens Fadiena. Underwater Surveys in Palaeo-Watercourses (ferrara District - Italy)

Science.gov (United States)

Bucci, G.

2015-04-01

In the ambit of our program of researches on ancient rivers in Ferrara hinterland (Italy), we have been joining a Scientific - Didactic Project between Soprintendenza per i Beni Archeologici dell'Emilia Romagna, Comune di Portomaggiore Assessorato alla Cultura, CMAS A.CDCI. - Confédération Mondiale des Activités Subaquatiques Federation ITA F07 - Associazione CMAS Diving Center Italia. The Project is focused on underwater archaeological surveys in ex quarry lakes, following the Rivers Padus and Sandalus between Voghiera, Gambulaga and Portomaggiore (Ferrara District). Here we are going to introduce our most recent results, after the last immersions and a 3D bathymetrical survey completed by echo-side scan sonar in Tramonto Lake at Gambulaga, explaining the connection with remote sensing investigations and direct surveys applied to underwater archaeology of the inland water. The main submerged structure individuated is a part of wooden dock on the left side of Padus, in front of the Necropolis of Fadieni (1st-3rd cent. A.D.). Thanks to the study of 183 finds coming from the lake, involving students and young collaborators of the Archaeological National Museum of Ferrara, we are reconstructing the ancient landscape between Proto-Imperial Age and Late Antique.

Medical devices made into weapons by prisoners: an unrecognized risk.

Science.gov (United States)

Hayden, J W; Laney, C; Kellermann, A L

1995-12-01

The alteration of a knee immobilizer into a sharp weapon by a prisoner prompted us to survey neighboring penal institutions to determine the frequency of such events. We mailed a nine-item survey to all detention facilities in Tennessee, Arkansas, and Mississippi. A second survey was sent to nonresponding institutions 6 weeks after the initial mailing. The Regional Medical Center at Memphis, the designated facility for evaluation and treatment of prisoners from the county jail and state penitentiary. Survey respondents included 25 state penitentiaries, 31 county jails, 1 state minimum-security facility, 1 state maximum-security facility, 1 work-release center, 1 county detention center for drunken-driving offenders, and 1 federal penitentiary. Of the 81 institutions surveyed, 77% responded to one of the two mailings. Forty percent responded in the affirmative when asked whether stolen or unauthorized medical equipment from outside their institutions had been discovered among inmates. When respondents were questioned as to whether medical equipment, prescribed or not, had been used or altered in a criminal manner, 34% responded "yes." Medications and medical appliances were listed in the responses. A survey of 81 local and neighboring penal institutions in a three-state area revealed that the illicit use of medicine and medical devices by prisoners is a legitimate safety concern of prison personnel and health care workers when medical care for inmates must be sought outside the security of their institutions. The modification of medical equipment into weapons by incarcerated patients, although clearly recognized as a security and safety problem by police authorities, appears to be unappreciated by health care workers providing episodic care to inmates.

The Theseus Autonomous Underwater Vehicle: A Canadian Success Story

Science.gov (United States)

1997-04-01

P502414.PDF [Page: 1 of 9] P502414.PDF [Page: 2 of 9] P502414.PDF [Page: 3 of 9] The Theseus Autonomous Underwater Vehicle A Canadian Success Story...autonomous underwater vehicle, named Theseus , for laying optical fiber cables in ice- covered waters. In trials and missions conducted in 1996, this...stations. An acoustic telemetry system enables communication with Theseus from surface stations, and an optical telemetry system is used for system

Consequences of the Use of Neutron Weapons

International Nuclear Information System (INIS)

Ilijas, B.

1998-01-01

In modern conceptions of the use of nuclear weapons there is a significant role of so called enhanced radiation weapons, also known as neutron weapons. Its most important feature is that all other effects (blast, thermal) are minimized in favour of neutron radiation. Because of the great penetrative capability and biological efficiency, neutron beam is ideal weapon against people in shelters and armoured vehicles. Material goods stay saved and also there is no significant long- term radioactive contamination. After the use of this weapons, which is possible even for tactical tasks on limited area, one must count with great number of people irradiated with doses in wide range - from those enough for instantaneous incapacitation to those which cause only long-term effects. For the purpose of maximal efficiency in this situation, it is necessary to work out plans for dosimetric control, first aid, transport and medical treatment of irradiated people (soldiers and civilians) in war conditions. (author)

The Effects of Nuclear Weapons

Energy Technology Data Exchange (ETDEWEB)

Glasstone, Samuel

1964-02-01

This book is a revision of "The Effects of Nuclear Weapons" which was issued in 1957. It was prepared by the Defense Atomic Support Agency of the Department of Defense in coordination with other cognizant governmental agencies and was published by the U.S. Atomc Energy Commission. Although the complex nature of nuclear weapons effects does not always allow exact evaluation, the conclusions reached herein represent the combined judgment of a number of the most competent scientists working the problem. There is a need for widespread public understanding of the best information available on the effects of nuclear weapons. The purpose of this book is to present as accurately as possible, within the limits of national security, a comprehensive summary of this information.

Coordinated Formation Control of Multiple Autonomous Underwater Vehicles for Pipeline Inspection

Directory of Open Access Journals (Sweden)

Xianbo Xiang

2010-02-01

Full Text Available This paper addresses the control problem of inspecting underwater pipeline on the seabed, with coordinated multiple autonomous underwater vehicles in a formation. Based on the leader-follower strategy, the dedicated nonlinear path following controller is rigorously built on Lyapunov-based design, driving a fleet of vehicles onto assigned parallel paths elevated and offset from the underwater pipeline, while keeping a triangle formation to capture complete 3D images for inspection. Due to the spatial-temporal decoupling characteristics of individual path following controller, the velocities of the followers can be adapted in the coordinated control level, only relying on the information of generalized along-path length from the leader, in order to build the desired formation. Thus, the communication variable broadcast from the leader is kept to a minimum, which is feasible under the severely constraints of acoustic communication bandwidth. Simulation results illustrate the efficiency of coordinated formation controller proposed for underwater pipeline inspection.

Why are sexually selected weapons almost absent in females?

Directory of Open Access Journals (Sweden)

Anders BERGLUND

2013-08-01

Full Text Available In sex role reversed species, predominantly females evolve sexually selected traits, such as ornaments and/or weapons. Female ornaments are common and their function well documented in many species, whether sex role reversed or not. However, sexually selected female weapons seem totally absent except for small wing spurs in three jacana species, present in both males and females. This poor female weaponry is in sharp contrast to the situation in species with conventional sex roles: males commonly have evolved sexually selected weapons as well as ornaments. At the same time, females in many taxa have naturally selected weapons, used in competition over resources or in predator defence. Why are sexually selected weapons then so rare, almost absent, in females? Here I briefly review weaponry in females and the function of these weapons, conclude that the near absence of sexually selected weapons begs an explanation, and suggest that costs of sexually selected weapons may exceed costs of ornaments. Females are more constrained when evolving sexually selected traits compared to males, at least compared to those males that do not provide direct benefits, as trait costs reduce a female’s fecundity. I suggest that this constraining trade-off between trait and fecundity restricts females to evolve ornaments but rarely weapons. The same may apply to paternally investing males. Whether sexually selected weapons actually are more costly than sexually selected ornaments remains to be investigated [Current Zoology 59 (4: 564–568, 2013].

Underwater Welding Techniques

OpenAIRE

Esam F. Alajmi; Ahmad A. Alqenaei

2017-01-01

Welding demand in offshore and marine applications is increased with the increasing in oil and gas activities as well as increasing in the marine transportation and industrial applications. Applications of underwater welding well be increased in Kuwait in the coming years due to the strategic directive of the country toward starting the offshore oil and gas exploration and production, and the increase in marine transportation projects. Therefore, there is a need to understand the concept of u...

Peaceful uses of nuclear weapon plutonium

International Nuclear Information System (INIS)

Burtak, F.

1996-01-01

In 1993, the U.S.A. and the CIS signed Start 2 (the Strategic Arms Reduction Treaty) in which they committed themselves the reduce their nuclear weapon arsenals to a fraction of that of 1991. For forty-five years the antagonism between the superpowers had been a dominating factor in world history, determining large areas of social life. When Start 2 will have been completed in 2003, some 200 t of weapon grade plutonium and some 2000 t of highly enriched uranium (Heu) will arise from dismantling nuclear weapons. In the absence of the ideological ballast of the debate about Communism versus Capitalism of the past few decades there is a chance of the grave worldwide problem of safe disposal and utilization of this former nuclear weapon material being solved. Under the heading of 'swords turned into plowshares', plutonium and uranium could be used for peaceful electricity generation. (orig.) [de

Weapons dismantlement issues in independent Ukraine

International Nuclear Information System (INIS)

Zack, N.R.

1995-01-01

The American Association for the Advancement of Science sponsored a seminar during September 1993 in Kiev, Ukraine, titled, ''Toward a Nuclear-Free Future--Barriers and Problems.'' It brought together Ukrainians, Belarusians and Americans to discuss the legal, political, economic, technical, and safeguards and security dimensions of nuclear weapons dismantlement and destruction. US representatives initiated discussions on legal and treaty requirements and constraints, safeguards and security issues surrounding dismantlement, storage and disposition of nuclear materials, warhead transportation, and economic considerations. Ukrainians gave presentations on arguments for and against the Ukraine keeping nuclear weapons, the Ukrainian Parliament's nonapproval of START 1, alternative strategies for dismantling silos and launchers, and economic and security implications of nuclear weapons removal from the Ukraine. Participants from Belarus discussed proliferation and control regime issues. This paper will highlight and detail the issues, concerns and possible impacts of the Ukraine's dismantlement of its nuclear weapons

Emerging nuclear energy systems and nuclear weapon proliferation

International Nuclear Information System (INIS)

Gsponer, A.; Sahin, S.; Jasani, B.

1983-01-01

Generally when considering problems of proliferation of nuclear weapons, discussions are focused on horizontal proliferation. However, the emerging nuclear energy systems currently have an impact mainly on vertical proliferation. The paper indicates that technologies connected with emerging nuclear energy systems, such as fusion reactors and accelerators, enhance the knowledge of thermonuclear weapon physics and will enable production of military useful nuclear materials (including some rare elements). At present such technologies are enhancing the arsenal of the nuclear weapon states. But one should not forget the future implications for horizontal proliferation of nuclear weapons as some of the techniques will in the near future be within the technological and economic capabilities of non-nuclear weapon states. Some of these systems are not under any international control. (orig.) [de

Beyond the nuclear weapon

International Nuclear Information System (INIS)

Quinlan, M.

2001-01-01

Since the end of the cold war, many people called for the elimination of nuclear weapons. That this decision seems difficult to realize because of the world political environment. Meanwhile the reduction of the nuclear weapons costs and risks believes more than ever a challenge of the international relations and more particularly in the proliferation domain. In this perspective the proliferation fight strategies need to be studied with a special interest in the domain of the alternatives and the possibilities of synergy. (A.L.B.)

Pakistan's Nuclear Weapons: Proliferation and Security Issues

National Research Council Canada - National Science Library

Kerr, Paul; Nikitin, Mary B

2007-01-01

Pakistan's nuclear arsenal consists of approximately 60 nuclear warheads. Pakistan continues fissile material production for weapons, and is adding to its weapons production facilities and delivery vehicles...

A Game-theoretical Approach for Distributed Cooperative Control of Autonomous Underwater Vehicles

KAUST Repository

Lu, Yimeng

2018-01-01

design and learning process of the algorithm are modified to fit specific constraints of underwater exploration/monitoring tasks. The revised approach can take the real scenario of underwater monitoring applications such as the effect of sea current

The key kinematic determinants of undulatory underwater swimming at maximal velocity.

Science.gov (United States)

Connaboy, Chris; Naemi, Roozbeh; Brown, Susan; Psycharakis, Stelios; McCabe, Carla; Coleman, Simon; Sanders, Ross

2016-01-01

The optimisation of undulatory underwater swimming is highly important in competitive swimming performance. Nineteen kinematic variables were identified from previous research undertaken to assess undulatory underwater swimming performance. The purpose of the present study was to determine which kinematic variables were key to the production of maximal undulatory underwater swimming velocity. Kinematic data at maximal undulatory underwater swimming velocity were collected from 17 skilled swimmers. A series of separate backward-elimination analysis of covariance models was produced with cycle frequency and cycle length as dependent variables (DVs) and participant as a fixed factor, as including cycle frequency and cycle length would explain 100% of the maximal swimming velocity variance. The covariates identified in the cycle-frequency and cycle-length models were used to form the saturated model for maximal swimming velocity. The final parsimonious model identified three covariates (maximal knee joint angular velocity, maximal ankle angular velocity and knee range of movement) as determinants of the variance in maximal swimming velocity (adjusted-r2 = 0.929). However, when participant was removed as a fixed factor there was a large reduction in explained variance (adjusted r2 = 0.397) and only maximal knee joint angular velocity continued to contribute significantly, highlighting its importance to the production of maximal swimming velocity. The reduction in explained variance suggests an emphasis on inter-individual differences in undulatory underwater swimming technique and/or anthropometry. Future research should examine the efficacy of other anthropometric, kinematic and coordination variables to better understand the production of maximal swimming velocity and consider the importance of individual undulatory underwater swimming techniques when interpreting the data.

Experimental Measurements of Temporal Dispersion for Underwater Laser Communications and Imaging

Science.gov (United States)

Cochenour, Brandon Michael

The challenge in implementing optical sensors underwater lies in the high variability of the ocean environment where propagation of light in the ocean is complicated by absorption and scattering. Most underwater optical sensors operate in the blue/green portion of the electromagnetic spectrum where seawater exhibits an absorption minimum. Mitigating scattering however is a greater challenge. In particular, scattering causes both spatial distortion (beam spreading) and temporal dispersion (pulse spreading or distortion). Each of type of dispersion decreases sensor performance (operating range, image resolution, data bandwidth, etc.). While spatial dispersion has received a great deal of attention in previous decades, technological limitations of sensor hardware have made experimental measurements of temporal dispersion underwater difficult until now. The main contribution of this thesis are experimental measurements of temporal dispersion of optical beams in turbid water, made with a high sensitivity/high dynamic range experimental technique. Measurements are performed as a function of water clarity (0-20 attenuation lengths), transmitter/receiver alignment (0-30 degrees, half angle), receiver field of view (1-7 degrees, full angle), and transmitter beam divergence (collimated and diffuse). Special attention is paid to the interdependency between spatial and temporal dispersion. This work provides severable notable contributions: 1. While experimental characterization of spatial dispersion has received significant attention underwater, there has been a lack of measurements characterizing temporal dispersion underwater. This work provides the most comprehensive set of experimental measurements to date regarding the temporal dispersion of optical beams underwater. 2. An experimental analysis of the influence of scattering phase function on temporal dispersion. Coarse estimates of the scattering phase function are used to determine the ranges (or attenuation lengths

Typical Underwater Tunnels in the Mainland of China and Related Tunneling Technologies

Directory of Open Access Journals (Sweden)

Kairong Hong

2017-12-01

Full Text Available In the past decades, many underwater tunnels have been constructed in the mainland of China, and great progress has been made in related tunneling technologies. This paper presents the history and state of the art of underwater tunnels in the mainland of China in terms of shield-bored tunnels, drill-and-blast tunnels, and immersed tunnels. Typical underwater tunnels of these types in the mainland of China are described, along with innovative technologies regarding comprehensive geological prediction, grouting-based consolidation, the design and construction of large cross-sectional tunnels with shallow cover in weak strata, cutting tool replacement under limited drainage and reduced pressure conditions, the detection and treatment of boulders, the construction of underwater tunnels in areas with high seismic intensity, and the treatment of serious sedimentation in a foundation channel of immersed tunnels. Some suggestions are made regarding the three potential great strait-crossing tunnels—the Qiongzhou Strait-Crossing Tunnel, Bohai Strait-Crossing Tunnel, and Taiwan Strait-Crossing Tunnel—and issues related to these great strait-crossing tunnels that need further study are proposed. Keywords: Underwater tunnel, Strait-crossing tunnel, Shield-bored tunnel, Immersed tunnel, Drill and blast

Emerging from Water: Underwater Image Color Correction Based on Weakly Supervised Color Transfer

OpenAIRE

Li, Chongyi; Guo, Jichang; Guo, Chunle

2017-01-01

Underwater vision suffers from severe effects due to selective attenuation and scattering when light propagates through water. Such degradation not only affects the quality of underwater images but limits the ability of vision tasks. Different from existing methods which either ignore the wavelength dependency of the attenuation or assume a specific spectral profile, we tackle color distortion problem of underwater image from a new view. In this letter, we propose a weakly supervised color tr...

Geometric and Optic Characterization of a Hemispherical Dome Port for Underwater Photogrammetry

Directory of Open Access Journals (Sweden)

Fabio Menna

2016-01-01

Full Text Available The popularity of automatic photogrammetric techniques has promoted many experiments in underwater scenarios leading to quite impressive visual results, even by non-experts. Despite these achievements, a deep understanding of camera and lens behaviors as well as optical phenomena involved in underwater operations is fundamental to better plan field campaigns and anticipate the achievable results. The paper presents a geometric investigation of a consumer grade underwater camera housing, manufactured by NiMAR and equipped with a 7′′ dome port. After a review of flat and dome ports, the work analyzes, using simulations and real experiments, the main optical phenomena involved when operating a camera underwater. Specific aspects which deal with photogrammetric acquisitions are considered with some tests in laboratory and in a swimming pool. Results and considerations are shown and commented.

A flexible liquid crystal polymer MEMS pressure sensor array for fish-like underwater sensing

International Nuclear Information System (INIS)

Kottapalli, A G P; Asadnia, M; Miao, J M; Barbastathis, G; Triantafyllou, M S

2012-01-01

In order to perform underwater surveillance, autonomous underwater vehicles (AUVs) require flexible, light-weight, reliable and robust sensing systems that are capable of flow sensing and detecting underwater objects. Underwater animals like fish perform a similar task using an efficient and ubiquitous sensory system called a lateral-line constituting of an array of pressure-gradient sensors. We demonstrate here the development of arrays of polymer microelectromechanical systems (MEMS) pressure sensors which are flexible and can be readily mounted on curved surfaces of AUV bodies. An array of ten sensors with a footprint of 60 (L) mm × 25 (W) mm × 0.4 (H) mm is fabricated using liquid crystal polymer (LCP) as the sensing membrane material. The flow sensing and object detection capabilities of the array are illustrated with proof-of-concept experiments conducted in a water tunnel. The sensors demonstrate a pressure sensitivity of 14.3 μV Pa −1 . A high resolution of 25 mm s −1 is achieved in water flow sensing. The sensors can passively sense underwater objects by transducing the pressure variations generated underwater by the movement of objects. The experimental results demonstrate the array’s ability to detect the velocity of underwater objects towed past by with high accuracy, and an average error of only 2.5%. (paper)

Multi-layer protective armour for underwater shock wave mitigation

OpenAIRE

Ahmed Hawass; Hosam Mostafa; Ahmed Elbeih

2015-01-01

The effect of underwater shock wave on different target plates has been studied. An underwater shock wave generator (shock tube) was used to study the interactions between water and different constructed targets which act as shock wave mitigation. Target plates, composed of sandwich of two aluminum sheets with rubber and foam in between, were prepared and studied. For comparison, the target plates composed of triple aluminum sheets were tested. The study includes the testing of the selected p...

Plutonium research and related activities at the Amarillo National Resource Center for Plutonium

International Nuclear Information System (INIS)

Hartley, R.S.; Beard, C.A.; Barnes, D.L.

1998-01-01

With the end of the Cold War, the US and Russia are reducing their nuclear weapons stockpiles. What to do with the materials from thousands of excess nuclear weapons is an important international challenge. How to handle the remaining US stockpile to ensure safe storage and reliability, in light of the aging support infrastructure, is an important national challenge. To help address these challenges and related issues, the Amarillo National Resource Center for Plutonium is working on behalf of the State of Texas with the US Department of Energy (DOE). The center directs three major programs that address the key aspects of the plutonium management issue: (1) the Communications, Education, Training and Community Involvement Program, which focuses on informing the public about plutonium and providing technical education at all levels; (2) the Environmental, Safety, and Health (ES and H) Program, which investigates the key ES and H impacts of activities related to the DOE weapons complex in Texas; and (3) the Nuclear and Other Materials Program, which is aimed at minimizing safety and proliferation risks by helping to develop and advocate safe stewardship, storage, and disposition of nuclear weapons materials. This paper provides an overview of the center's nuclear activities described in four broad categories of international activities, materials safety, plutonium storage, and plutonium disposition

Underwater noise due to precipitation

DEFF Research Database (Denmark)

Crum, Lawrence A.; Pumphrey, Hugh C.; Prosperetti, Andrea

1989-01-01

In 1959, G. Franz published a thorough investigation of the underwater sound produced by liquid drop impacts [G. Franz, J. Acoust. Soc. Am. 31, 1080 (1959)]. He discovered that, under certain conditions, a gas bubble was entrained by the impacting droplet, and the subsequent oscillation of this b...

Autonomous docking control of visual-servo type underwater vehicle system aiming at underwater automatic charging

International Nuclear Information System (INIS)

Yanou, Akira; Ohnishi, Shota; Ishiyama, Shintaro; Minami, Mamoru

2015-01-01

A visual-servo type remotely operated vehicle (ROV) system with binocular wide-angle lens was developed to survey submarine resources, decontaminate radiation from mud in dam lake and so on. This paper explores the experiments on regulator performance and underwater docking of the robot system utilizing Genetic Algorithm (GA) for real-time recognition of the robot's relative position and posture through 3D marker. The visual servoing performances have been verified as follows; (1) The stability performances of the proposed regulator system have been evaluated by exerting abrupt distrubane force while the ROV is controlled by visual servoing. (2) The proposed system can track time-variant desired target position in x-axis (front-back direction of the robot). (3) The underwater docking can be completed by switching visual servoing and docking modes based on the error threshold, and by giving time-varying desired target position and orientation to the controller as a desired pose. (author)

Democracy, public opinion, and nuclear weapons

International Nuclear Information System (INIS)

Russett, B.

1989-01-01

To the degree that people's fears of nuclear war are deep and pervasive, they become subject to manipulation by cynical or politically utopian promises, whether those promises be to abolish nuclear weapons from the earth or to create a leakproof peace shield (SDI). But the basic yearning for protection could also be mobilized to support serious arms reduction and arms control agreements. Nuclear weapons provide the basis for a vivid form of symbolic politics, perhaps equivalent in foreign policy considerations to the Korean and Vietnam wars during their durations, and in similar ways (although not necessarily as severe) as unemployment does among domestic policy issues. This paper presents survey research directed specifically at the role of public opinion on nuclear imagery (difference between expectation of nuclear war versus any kind of weapon war; willingness to spend on nuclear weapons versus conventional ones or general defense spending) can help in understanding these phenomena

A nuclear-weapon-free world and true disarmament

International Nuclear Information System (INIS)

Salvini, G.

1999-01-01

This preliminary note about is important to consider when discussing hopes of achieving a nuclear-weapon-free world. Without a serious effort to establish intelligent, powerful bodies to control and judge the behavior of the nations on Earth, whatever they future weapons may be, the objective to reach a nuclear-weapon-free world may even succeed, but it is not enough to stop wars and death. Even more than that: if taken alone, as the 'Great Way', it could prove negative, for it could slow down the general effort to achieve peace on out planet. A nuclear-weapon-free world is of course a very good idea but two points must be discussed: how to achieve the nuclear-weapon-free world; and what will happen afterwards. Some considerations on the second point are made

Robotics Vision-based Heuristic Reasoning for Underwater Target Tracking and Navigation

Directory of Open Access Journals (Sweden)

Chua Kia

2005-09-01

Full Text Available This paper presents a robotics vision-based heuristic reasoning system for underwater target tracking and navigation. This system is introduced to improve the level of automation of underwater Remote Operated Vehicles (ROVs operations. A prototype which combines computer vision with an underwater robotics system is successfully designed and developed to perform target tracking and intelligent navigation. This study focuses on developing image processing algorithms and fuzzy inference system for the analysis of the terrain. The vision system developed is capable of interpreting underwater scene by extracting subjective uncertainties of the object of interest. Subjective uncertainties are further processed as multiple inputs of a fuzzy inference system that is capable of making crisp decisions concerning where to navigate. The important part of the image analysis is morphological filtering. The applications focus on binary images with the extension of gray-level concepts. An open-loop fuzzy control system is developed for classifying the traverse of terrain. The great achievement is the system's capability to recognize and perform target tracking of the object of interest (pipeline in perspective view based on perceived condition. The effectiveness of this approach is demonstrated by computer and prototype simulations. This work is originated from the desire to develop robotics vision system with the ability to mimic the human expert's judgement and reasoning when maneuvering ROV in the traverse of the underwater terrain.

Robotics Vision-based Heuristic Reasoning for Underwater Target Tracking and Navigation

Directory of Open Access Journals (Sweden)

Chua Kia

2008-11-01

Full Text Available This paper presents a robotics vision-based heuristic reasoning system for underwater target tracking and navigation. This system is introduced to improve the level of automation of underwater Remote Operated Vehicles (ROVs operations. A prototype which combines computer vision with an underwater robotics system is successfully designed and developed to perform target tracking and intelligent navigation. This study focuses on developing image processing algorithms and fuzzy inference system for the analysis of the terrain. The vision system developed is capable of interpreting underwater scene by extracting subjective uncertainties of the object of interest. Subjective uncertainties are further processed as multiple inputs of a fuzzy inference system that is capable of making crisp decisions concerning where to navigate. The important part of the image analysis is morphological filtering. The applications focus on binary images with the extension of gray-level concepts. An open-loop fuzzy control system is developed for classifying the traverse of terrain. The great achievement is the system's capability to recognize and perform target tracking of the object of interest (pipeline in perspective view based on perceived condition. The effectiveness of this approach is demonstrated by computer and prototype simulations. This work is originated from the desire to develop robotics vision system with the ability to mimic the human expert's judgement and reasoning when maneuvering ROV in the traverse of the underwater terrain.

A Survey on Underwater Wireless Sensor Networks: Progresses, Applications, and Challenges

Directory of Open Access Journals (Sweden)

Premalatha J.

2016-01-01

Full Text Available The endangered underwater species always drew the attention of the scientific society since their disappearance would cause irreplaceable loss. Asia is home to some of the most diverse habitats in the earth, but it is estimated that more than one in four species are endangered. In Underwater, a lot of factors are putting marine life under immense pressure. Extreme population pressure is leading to pollution, over-fishing and the devastation of crucial habitats. Consequently, the numbers of almost all fish are declining and many are already endangered. To help these species to survive, their habitat should be strictly protected. This can be achieved by strictly monitoring them. During this course, several parameters, constraints about the species and its environments are focused. Now, advances in sensor technology facilitate the monitoring of species and their habitat with less expenditure. Indeed, the increasing sophistication of underwater wireless sensors offers chances that enable new challenges in a lot of areas, like surveillance one. This paper endorses the use of sensors for monitoring underwater species endangered in their habitat. This paper further examines the key approaches and challenges in the design and implementation of underwater wireless sensor networks. We summarize major applications and the main phenomena related to acoustic propagation, and discuss how they affect the design and operation of communication systems and networking protocols at various layers.

Strong tracking adaptive Kalman filters for underwater vehicle dead reckoning

Institute of Scientific and Technical Information of China (English)

XIAO Kun; FANG Shao-ji; PANG Yong-jie

2007-01-01

To improve underwater vehicle dead reckoning, a developed strong tracking adaptive kalman filter is proposed. The filter is improved with an additional adaptive factor and an estimator of measurement noise covariance. Since the magnitude of fading factor is changed adaptively, the tracking ability of the filter is still enhanced in low velocity condition of underwater vehicles. The results of simulation tests prove the presented filter effective.

Microcontroller-based underwater acoustic ECG telemetry system.

Science.gov (United States)

Istepanian, R S; Woodward, B

1997-06-01

This paper presents a microcontroller-based underwater acoustic telemetry system for digital transmission of the electrocardiogram (ECG). The system is designed for the real time, through-water transmission of data representing any parameter, and it was used initially for transmitting in multiplexed format the heart rate, breathing rate and depth of a diver using self-contained underwater breathing apparatus (SCUBA). Here, it is used to monitor cardiovascular reflexes during diving and swimming. The programmable capability of the system provides an effective solution to the problem of transmitting data in the presence of multipath interference. An important feature of the paper is a comparative performance analysis of two encoding methods, Pulse Code Modulation (PCM) and Pulse Position Modulation (PPM).

Neutron weapons. War prevention by credible deterrence

International Nuclear Information System (INIS)

1981-11-01

The neutron bomb has prompted fierce and controversial public discussions which are more emotional than based on facts. Unaware of the factual repercussions this weapon has, it has been described as the most inhumane weapon ever. By saying so, the public is wrongly informed and is made feel insecure. The following contributions made by competent authorities may be used for getting to the point, pointing out that the neutron bomb is primarily a defensive weapon. (orig.) [de

Automated Navigation System based on Weapon-Target Assignment

Directory of Open Access Journals (Sweden)

Mohammad Khairudin

2011-12-01

Full Text Available Operating of weapon on the tank is mostly by manually. It is not desired performance for a critical operation. An automatic control system is required to operate the weapon with the target while maintaining the accuracy. In this paper has designed an automatic weapon control system using object image proccessing. Various an image processing methods used to improve the weapon accuracy to obtain the intended target. The method used in digital image processing is the Camshift motion tracking method. This method is compared with the Lucas Canade motion tracking method. This comparison is conducted to found more precise results between the two methods. Results of object image processing are used to control the direction of the weapon that towards the desired goal. The results show that the implementation of the Lucas Canade motion tracking method using fire simulation tools have been successful. The performance of the Lucas Canade motion tracking methods is better than the CamShift method. Using Lucas Canade method for weapon controller is accordance with the purposes.

Nuclear weapon-free zone, non-proliferation treaty and South Asia

International Nuclear Information System (INIS)

Jayaramu, P.S.

1980-01-01

Emergence of and the motivations behind the concept of nuclear weapon free zone, the conceptual linkage between the nuclear weapon free zone and the Non-Proliferation Treaty and the problems involved in the implementation of nuclear weapon free zone proposals put forward from time to time are discussed. Pakistan's proposal for a nuclear weapon free zone in South Asia, motivations behind the proposal, and India's response to it are examined. It is pointed out that both the NPT and nuclear weapon free zone indirectly grant a certain amount of legitimacy to the use of nuclear weapons. (M.G.B.)

QFD-based conceptual design of an autonomous underwater robot

Directory of Open Access Journals (Sweden)

Thip Pasawang

2015-12-01

Full Text Available Autonomous underwater robots in the past few years have been designed according to the individual concepts and experiences of the researchers. To design a robot, which meets all the requirements of potential users, is an advanced work. Hence, a systematic design method that could include users’ preferences and requirements is needed. This paper presents the quality function deployment (QFD technique to design an autonomous underwater robot focusing on the Thai Navy military mission. Important user requirements extracted from the QFD method are the ability to record videos, operating at depth up to 10 meters, the ability to operate remotely with cable and safety concerns related to water leakages. Less important user requirements include beauty, using renewable energy, operating remotely with radio and ability to work during night time. The important design parameters derived from the user requirements are a low cost-controller, an autonomous control algorithm, a compass sensor and vertical gyroscope, and a depth sensor. Of low-importance ranked design parameters include the module design, use clean energy, a low noise electric motor, remote surveillance design, a pressure hull, and a beautiful hull form design. The study results show the feasibility of using QFD techniques to systematically design the autonomous underwater robot to meet user requirements. Mapping between the design and expected parameters and a conceptual drafting design of an autonomous underwater robot are also presented.

Overview of surplus weapons plutonium disposition

Energy Technology Data Exchange (ETDEWEB)

Rudy, G.

1996-05-01

The safe disposition of surplus weapons useable plutonium is a very important and urgent task. While the functions of long term storage and disposition directly relate to the Department`s weapons program and the environmental management program, the focus of this effort is particularly national security and nonproliferation.

Experimental Study on the Measurement of Water Bottom Vibration Induced by Underwater Drilling Blasting

Directory of Open Access Journals (Sweden)

Gu Wenbin

2015-01-01

Full Text Available Due to the lack of proper instrumentations and the difficulties in underwater measurements, the studies about water bottom vibration induced by underwater drilling blasting are seldom reported. In order to investigate the propagation and attenuation laws of blasting induced water bottom vibration, a water bottom vibration monitor was developed with consideration of the difficulties in underwater measurements. By means of this equipment, the actual water bottom vibration induced by underwater drilling blasting was measured in a field experiment. It shows that the water bottom vibration monitor could collect vibration signals quite effectively in underwater environments. The followed signal analysis shows that the characteristics of water bottom vibration and land ground vibration induced by the same underwater drilling blasting are quite different due to the different geological environments. The amplitude and frequency band of water bottom vibration both exceed those of land ground vibration. Water bottom vibration is mainly in low-frequency band that induced by blasting impact directly acts on rock. Besides the low-frequency component, land vibration contains another higher frequency band component that induced by followed water hammer wave acts on bank slope.

Public perspectives of nuclear weapons in the post-cold war environment

Energy Technology Data Exchange (ETDEWEB)

Jenkins-Smith, H.C.; Herron, K.G. [Univ. of New Mexico, Albuquerque, NM (United States). Institute for Public Policy; Barke, R.P. [Georgia Institute of Technology, Atlanta, GA (United States). School of Public Policy

1994-04-01

This report summarizes the findings of a nationwide survey of public perceptions of nuclear weapons in the post-cold war environment. Participants included 1,301 members of the general public, 1,155 randomly selected members of the Union of Concerned Scientists, and 1,226 employees randomly selected from the technical staffs of four DOE national laboratories. A majority of respondents from all three samples perceived the post-cold war security environment to pose increased likelihood of nuclear war, nuclear proliferation, and nuclear terrorism. Public perceptions of nuclear weapons threats, risks, utilities, and benefits were found to systematically affect nuclear weapons policy preferences in predictable ways. Highly significant relationships were also found between public trust and nuclear weapons policy preferences. As public trust and official government information about nuclear weapons increased, perceptions of nuclear weapons management risks decreased and perceptions of nuclear weapons utilities and benefits increased. A majority of respondents favored decreasing funding for: (1) developing and testing new nuclear weapons; (2) maintaining existing nuclear weapons, and (3) maintaining the ability to develop and improve nuclear weapons. Substantial support was found among all three groups for increasing funding for: (1) enhancing nuclear weapons safety; (2) training nuclear weapons personnel; (3) preventing nuclear proliferation; and (4) preventing nuclear terrorism. Most respondents considered nuclear weapons to be a persistent feature of the post-cold war security environment.

Instruments of war weapons and technologies that have changed history

CERN Document Server

Tucker, Spencer C

2015-01-01

In war, the weapons and technologies employed have direct effects on how battles are waged. When new weapons are introduced, they can dramatically alter the outcomes of warfare-and consequently change the course of history itself. This reference work provides a fascinating overview of the major weapon systems and military technologies that have had a major impact on world history. Addressing weapons as crude as the club used by primitive man to the high-tech weapons of today such as unmanned drones, Instruments of War: Weapons and Technologies That Have Changed History offers nearly 270 profusely illustrated entries that examine the key roles played by specific weapons and identify their success and failures. The book begins with an introductory essay that frames the subject matter of the work and discusses the history of weapons as a whole. The text is concise and accessible to general readers without extensive backgrounds in military history yet provides the detailed information necessary to convey the comp...

Short-Range Sensor for Underwater Robot Navigation using Line-lasers and Vision

DEFF Research Database (Denmark)

Hansen, Peter Nicholas; Nielsen, Mikkel Cornelius; Christensen, David Johan

2015-01-01

This paper investigates a minimalistic laser-based range sensor, used for underwater inspection by Autonomous Underwater Vehicles (AUV). This range detection system system comprise two lasers projecting vertical lines, parallel to a camera’s viewing axis, into the environment. Using both lasers...

Psychological markers underlying murder weapon profile: a quantitative study.

Science.gov (United States)

Kamaluddin, M R; Othman, A; Ismail, K H; Mat Saat, G A

2017-12-01

The horrific nature of murder using different types of weapons has been an important focal point of many criminological studies. Weapons that are used in murders seem to play dominant roles in murder investigations as they may provide information leading to arrest. The established factors for weapon usage include environmental context, demography and availability of weapons. However, there is insufficient research attention on the psychological functioning of murderers for particular weapon usage. In light of this, the current study seeks to narrow this gap of information by identifying the influences of psychological traits on weapon usage among a sample of male murderers. The present cross-sectional study was conducted among 71 male murderers incarcerated in 11 prisons within Peninsular Malaysia. The selection of the sample was based on predetermined selection criteria using a purposive sampling method. A guided self-administered questionnaire comprising sociodemography variables and four Malay validated psychometric instruments: Zuckerman-Kuhlman Personality Questionnaire-40-Cross-Culture, Self-control Scale, "How I Think" Questionnaire and Aggression Questionnaire; was used. Independent sample t-test was performed to establish the mean score differences of psychological traits between the murderers who used single and multiple weapons while Kruskal-Wallis tests were carried out to ascertain the differences between the specific types of weapons used among the murderers. Following this, one-way ANOVA was carried out to ascertain the psychological trait differences among the murderers according to the different sources of weapon. Results indicated specific psychological traits influenced the number(s), source(s) and type(s) of weapon used in committing murder. The findings have implications for the psychological profiling of unknown murderers within the Malaysian context.

Weapon container catalog. Volumes 1 & 2

Energy Technology Data Exchange (ETDEWEB)

Brown, L.A.; Higuera, M.C.

1998-02-01

The Weapon Container Catalog describes H-gear (shipping and storage containers, bomb hand trucks and the ancillary equipment required for loading) used for weapon programs and for special use containers. When completed, the catalog will contain five volumes. Volume 1 for enduring stockpile programs (B53, B61, B83, W62, W76, W78, W80, W84, W87, and W88) and Volume 2, Special Use Containers, are being released. The catalog is intended as a source of information for weapon program engineers and also provides historical information. The catalog also will be published on the SNL Internal Web and will undergo periodic updates.

Ocean Research Enabled by Underwater Gliders.

Science.gov (United States)

Rudnick, Daniel L

2016-01-01

Underwater gliders are autonomous underwater vehicles that profile vertically by changing their buoyancy and use wings to move horizontally. Gliders are useful for sustained observation at relatively fine horizontal scales, especially to connect the coastal and open ocean. In this review, research topics are grouped by time and length scales. Large-scale topics addressed include the eastern and western boundary currents and the regional effects of climate variability. The accessibility of horizontal length scales of order 1 km allows investigation of mesoscale and submesoscale features such as fronts and eddies. Because the submesoscales dominate vertical fluxes in the ocean, gliders have found application in studies of biogeochemical processes. At the finest scales, gliders have been used to measure internal waves and turbulent dissipation. The review summarizes gliders' achievements to date and assesses their future in ocean observation.

North Korea's nuclear weapons development. Implications for future policy

International Nuclear Information System (INIS)

Pollack, J.D.

2010-01-01

, making it the only state ever to do so, and in February 2005 it declared that it possessed nuclear weapons. It attempted long-range missile launches in July 2006 and April 2009, conducted nuclear tests in October 2006 and May 2009, and since late 2008 has claimed status as a nuclear weapons state outside the NPT. The shortcomings and outright failures in nuclear diplomacy with the DPRK have a long lineage. Under the Agreed Framework of October 1994, the Clinton Administration bought time by freezing North Korea's plutonium production capabilities, but a comprehensive resolution of controversies that triggered the first nuclear crisis was deferred indefinitely. The Bush Administration was openly contemptuous of the arrangements negotiated under its predecessor and walked away from the Agreed Framework, but it lacked a credible fallback plan when Pyongyang resumed its plutonium-based activities. Some senior Bush Administration officials, moreover, were convinced that North Korea would wilt under pressure or even collapse outright, but the DPRK defied such expectations, and moved quickly toward an avowed weapons capability. The DPRK's long pursuit of strategic autonomy, however, remains at the center of this story, and starkly contradicts the North's claims that it is intent on a non-nuclear future. North Korea signed various agreements that, at least in theory, invalidated pursuit of nuclear weapons. These agreements included Pyongyang's assent to basic non-proliferation documents; an inter-Korean accord that entered into force in 1992; bilateral agreements with the United States; and multilateral declarations negotiated at the Six-Party Talks in Beijing in 2005 and 2007. But negotiated agreements failed to eliminate the North Korea's pursuit of the technologies and expertise necessary for a weapons program. By walking away from these agreements, Pyongyang compelled Washington and other capitals to undertake reassessments of previous policies. (author)

Natural and bio-inspired underwater adhesives: Current progress and new perspectives

Science.gov (United States)

Cui, Mengkui; Ren, Susu; Wei, Shicao; Sun, Chengjun; Zhong, Chao

2017-11-01

Many marine organisms harness diverse protein molecules as underwater adhesives to achieve strong and robust interfacial adhesion under dynamic and turbulent environments. Natural underwater adhesion phenomena thus provide inspiration for engineering adhesive materials that can perform in water or high-moisture settings for biomedical and industrial applications. Here we review examples of biological adhesives to show the molecular features of natural adhesives and discuss how such knowledge serves as a heuristic guideline for the rational design of biologically inspired underwater adhesives. In view of future bio-inspired research, we propose several potential opportunities, either in improving upon current L-3, 4-dihydroxyphenylalanine-based and coacervates-enabled adhesives with new features or engineering conceptually new types of adhesives that recapitulate important characteristics of biological adhesives. We underline the importance of viewing natural adhesives as dynamic materials, which owe their outstanding performance to the cellular coordination of protein expression, delivery, deposition, assembly, and curing of corresponding components with spatiotemporal control. We envision that the emerging synthetic biology techniques will provide great opportunities for advancing both fundamental and application aspects of underwater adhesives.

Natural and bio-inspired underwater adhesives: Current progress and new perspectives

Directory of Open Access Journals (Sweden)

Mengkui Cui

2017-11-01

Full Text Available Many marine organisms harness diverse protein molecules as underwater adhesives to achieve strong and robust interfacial adhesion under dynamic and turbulent environments. Natural underwater adhesion phenomena thus provide inspiration for engineering adhesive materials that can perform in water or high-moisture settings for biomedical and industrial applications. Here we review examples of biological adhesives to show the molecular features of natural adhesives and discuss how such knowledge serves as a heuristic guideline for the rational design of biologically inspired underwater adhesives. In view of future bio-inspired research, we propose several potential opportunities, either in improving upon current L-3, 4-dihydroxyphenylalanine-based and coacervates-enabled adhesives with new features or engineering conceptually new types of adhesives that recapitulate important characteristics of biological adhesives. We underline the importance of viewing natural adhesives as dynamic materials, which owe their outstanding performance to the cellular coordination of protein expression, delivery, deposition, assembly, and curing of corresponding components with spatiotemporal control. We envision that the emerging synthetic biology techniques will provide great opportunities for advancing both fundamental and application aspects of underwater adhesives.

Cluster protocols in Underwater Sensor Networks: a Research Review

Directory of Open Access Journals (Sweden)

K. Ovaliadis

2014-07-01

Full Text Available Underwater Wireless Sensor Networks (UWSN have different characteristics in relation to terrestrial wireless sensor networks; such as limited bandwidth capacity, high propagation delays and limited battery power. Although there has been much work completed in developing protocols and models for terrestrial networks, these are rarely applicable for underwater sensor networks. Up to today major efforts have been made for designing efficient protocols while considering the underwater communication characteristics. An important issue on this research area is the construction of an efficient clustering algorithm. Clustering in the context of UWSN is important as it contributes a great deal towards the efficient use of energy resources. This paper reviews the most significant cluster based protocols proposed for UWSN. Major performance issues of these protocols with respect to the network conditions such as packet delivery ratio, average packet delay, node mobility effect and energy consumption are examined. The advantages and disadvantages of each protocol are also pointed out.

Automated gravity gradient tensor inversion for underwater object detection

International Nuclear Information System (INIS)

Wu, Lin; Tian, Jinwen

2010-01-01

Underwater abnormal object detection is a current need for the navigation security of autonomous underwater vehicles (AUVs). In this paper, an automated gravity gradient tensor inversion algorithm is proposed for the purpose of passive underwater object detection. Full-tensor gravity gradient anomalies induced by an object in the partial area can be measured with the technique of gravity gradiometry on an AUV. Then the automated algorithm utilizes the anomalies, using the inverse method to estimate the mass and barycentre location of the arbitrary-shaped object. A few tests on simple synthetic models will be illustrated, in order to evaluate the feasibility and accuracy of the new algorithm. Moreover, the method is applied to a complicated model of an abnormal object with gradiometer and AUV noise, and interference from a neighbouring illusive smaller object. In all cases tested, the estimated mass and barycentre location parameters are found to be in good agreement with the actual values

15 CFR 742.18 - Chemical Weapons Convention (CWC or Convention).

Science.gov (United States)

2010-01-01

... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Chemical Weapons Convention (CWC or... REGULATIONS CONTROL POLICY-CCL BASED CONTROLS § 742.18 Chemical Weapons Convention (CWC or Convention). States... Use of Chemical Weapons and on Their Destruction, also known as the Chemical Weapons Convention (CWC...

Underwater Robots Surface in Utah

Science.gov (United States)

Hurd, Randy C.; Hacking, Kip S.; Damarjian, Jennifer L.; Wright, Geoffrey A.; Truscott, Tadd

2015-01-01

Underwater robots (or ROVs: Remotely Operated Vehicles as they are typically called in industry) have recently become a very popular instructional STEM activity. Nationally, ROVs have been used in science and technology classrooms for several years in cities such as Seattle, San Diego, Virginia Beach, and other coastal areas. In the past two…

A Game-theoretical Approach for Distributed Cooperative Control of Autonomous Underwater Vehicles

KAUST Repository

Lu, Yimeng

2018-05-01

This thesis explores a game-theoretical approach for underwater environmental monitoring applications. We first apply game-theoretical algorithm to multi-agent resource coverage problem in drifting environments. Furthermore, existing utility design and learning process of the algorithm are modified to fit specific constraints of underwater exploration/monitoring tasks. The revised approach can take the real scenario of underwater monitoring applications such as the effect of sea current, previous knowledge of the resource and occasional communications between agents into account, and adapt to them to reach better performance. As the motivation of this thesis is from real applications, in this work we emphasize highly on implementation phase. A ROS-Gazebo simulation environment was created for preparation of actual tests. The algorithms are implemented in simulating both the dynamics of vehicles and the environment. After that, a multi-agent underwater autonomous robotic system was developed for hardware test in real settings with local controllers to make their own decisions. These systems are used for testing above mentioned algorithms and future development of other underwater projects. After that, other works related to robotics during this thesis will be briefly mentioned, including contributions in MBZIRC robotics competition and distributed control of UAVs in an adversarial environment.

Dismantlement and destruction of chemical, nuclear and conventional weapons

International Nuclear Information System (INIS)

Schulte, N.T.

1997-01-01

The safe destruction and dismantling of chemical, nuclear and conventional weapons is of fundamental importance to the security of all countries represented in this volume. Expertise in the field is not confined to one country or organisation: all can benefit from each other. There is an ever present danger of proliferation of weapons of mass destruction: approximately two dozen countries have ongoing programmes to develop or acquire such weapons, and many are also gaining the capability to build air-surface delivery systems. But much can be done to prevent proliferation by reducing leakage of materials and know-how and by solving the problems of the destruction of surplus weapons systems, which has now come to be a key issue. In 13 sessions of the workshop attention was paid to (1) Dismantlement and Destruction of Chemical, Nuclear and Conventional Weapons; (2) Status of Implementation of Arms Control Treaties and Voluntary Commitments; (3) National Perspectives on Cooperation in Disarmament; (4) Stocktaking of National and Bilateral Disposal/Destruction Programmes: Chemical Weapons; (5) Stocktaking of National and Bilateral Disposal/Destruction Programmes: Nuclear Weapons; (6) Stocktaking of National and Bilateral Disposal/Destruction Programmes: Conventional Weapons. Session; (7) Experience with Currently Employed Chemical Destruction Technologies; (8) Alternative Chemical Destruction Technologies; (9) Deactivation, Dismantlement and Destruction of Delivery Systems and Infrastructure for Nuclear Weapons; (10) Storage, Safeguarding and Disposition of Fissile Materials; (11) Technologies for Conversion and Civil Use of Demilitarized Materials; (12) International Organizations; and (13) Environmental Challenges Posed by Chemical and Nuclear Disarmament

Self-Assembling Multi-Component Nanofibers for Strong Bioinspired Underwater Adhesives

Science.gov (United States)

Zhong, Chao; Gurry, Thomas; Cheng, Allen A; Downey, Jordan; Deng, Zhengtao; Stultz, Collin M.; Lu, Timothy K

2014-01-01

Many natural underwater adhesives harness hierarchically assembled amyloid nanostructures to achieve strong and robust interfacial adhesion under dynamic and turbulent environments. Despite recent advances, our understanding of the molecular design, self-assembly, and structure-function relationship of those natural amyloid fibers remains limited. Thus, designing biomimetic amyloid-based adhesives remains challenging. Here, we report strong and multi-functional underwater adhesives obtained from fusing mussel foot proteins (Mfps) of Mytilus galloprovincialis with CsgA proteins, the major subunit of Escherichia coli amyloid curli fibers. These hybrid molecular materials hierarchically self-assemble into higher-order structures, in which, according to molecular dynamics simulations, disordered adhesive Mfp domains are exposed on the exterior of amyloid cores formed by CsgA. Our fibers have an underwater adhesion energy approaching 20.9 mJ/m2, which is 1.5 times greater than the maximum of bio-inspired and bio-derived protein-based underwater adhesives reported thus far. Moreover, they outperform Mfps or curli fibers taken on their own at all pHs and exhibit better tolerance to auto-oxidation than Mfps at pH ≥7.0. This work establishes a platform for engineering multi-component self-assembling materials inspired by nature. PMID:25240674

Synthesis and Development of Gold Polypyrrole Actuator for Underwater Application

Science.gov (United States)

Panda, S. K.; Bandopadhya, D.

2018-02-01

Electro-active polymer (EAP) such as Polypyrrole has gained much attention in the category of functional materials for fabrication of both active actuator and sensor. Particularly, PPy actuator has shown potential in fluid medium application because of high strain, large bending displacement and work density. This paper focuses on developing a low cost active actuator promising in delivering high performance in underwater environment. The proposed Au-pyrrole actuator is synthesized by adopting the layer-by-layer electrochemical polymerization technique and is fabricated as strip actuator from aqueous solution of Pyrrole and NaDBS in room temperature. In the follow-up, topographical analysis has been carried out using SEM and FESEM instruments showing surface morphology and surface integrity of chemical components of the structure. Several experiments have been conducted under DC input voltage evaluating performance effectiveness such as underwater bending displacement and tip force etc. This is observed that the actuator exhibits quite similar stress profile as of natural muscle, endowed with high modulus makes them effective in working nearly 10,000 cycles underwater environment. In addition, the bending displacement up to 5.4 mm with a low input voltage 1.3 V makes the actuator suitable for underwater micro-robotics applications.

Nuclear weapons in Europe: Why zero is better

International Nuclear Information System (INIS)

Daalder, I.H.

1993-01-01

Given the fundamental changes in the political context and NATO's perception of nuclear weapons, what role remains for US nuclear weapons in preserving security in Europe? Are US nuclear deployments on the continent still necessary? Is there a requirement for extended deterrence and, if so, does its credibility depend on the continued basing of US nuclear weapons in Europe? And what is the role of arms control in effecting any desirable restructuring in nuclear force postures? In addressing these questions, it becomes clear that US nuclear weapons can now be removed from Europe - they no longer serve the political and military functions they once did

Strategies for denaturing the weapons-grade plutonium stockpile

International Nuclear Information System (INIS)

Buckner, M.R.; Parks, P.B.

1992-10-01

In the next few years, approximately 50 metric tons of weapons-grade plutonium and 150 metric tons of highly-enriched uranium (HEU) may be removed from nuclear weapons in the US and declared excess. These materials represent a significant energy resource that could substantially contribute to our national energy requirements. HEU can be used as fuel in naval reactors, or diluted with depleted uranium for use as fuel in commercial reactors. This paper proposes to use the weapons-grade plutonium as fuel in light water reactors. The first such reactor would demonstrate the dual objectives of producing electrical power and denaturing the plutonium to prevent use in nuclear weapons

Experimental study on underwater electrical explosion of a copper wire

International Nuclear Information System (INIS)

Zhou Qing; Zhang Jun; Tan Xiangyu; Ren Baozhong; Zhang Qiaogen

2010-01-01

Through analyzing the physical process of underwater electrical wire explosion, electrical wire explosions with copper wires were investigated underwater using pulsed voltage in the time scale of a few microseconds. A self-integrating Rogowsky coil and a voltage divider were used for current and voltage at the wire load, respectively. The shock wave pressure is measured with a piezoelectric pressure probe at the same distance. The current rise rate was adjusted by changing the applied voltage, circuit inductance, length and diameter of copper wire. The change of the current rise rate had a great effect on the process of underwater electrical wire explosion with copper wires. At last, the effect of discharge voltage, circuit inductance, length and diameter of copper wire were obtained on the explosion voltage and current as well as shock wave pressure. (authors)

Underwater Time Service and Synchronization Based on Time Reversal Technique

Science.gov (United States)

Lu, Hao; Wang, Hai-bin; Aissa-El-Bey, Abdeldjalil; Pyndiah, Ramesh

2010-09-01

Real time service and synchronization are very important to many underwater systems. But the time service and synchronization in existence cannot work well due to the multi-path propagation and random phase fluctuation of signals in the ocean channel. The time reversal mirror technique can realize energy concentration through self-matching of the ocean channel and has very good spatial and temporal focusing properties. Based on the TRM technique, we present the Time Reversal Mirror Real Time service and synchronization (TRMRT) method which can bypass the processing of multi-path on the server side and reduce multi-path contamination on the client side. So TRMRT can improve the accuracy of time service. Furthermore, as an efficient and precise method of time service, TRMRT could be widely used in underwater exploration activities and underwater navigation and positioning systems.

Self-flowing underwater concrete mixtures for high rise structures

International Nuclear Information System (INIS)

Yousri, K.M.

2005-01-01

Placement of conventional concrete mixtures in underwater construction results in a high percentage of material loss due to washout of cement paste. This paper presents the influence of anti washout admixture (AWA) on various properties of concrete. Eleven self-flowing concrete (SFC) mixtures using type II cement were proportioned. A combination of low water cement (w/c), high cement contents, anti washout admixtures, fly ash, and silica fume were used to enhance the resistance of fresh concrete to washout. The concrete mixtures proportioned to be highly flow able, self-leveling and cohesive. The water-cementitious materials ratios ranged between 0.356 and 0.392 which correspond a typical underwater concrete mixture. The concrete mixtures were tested for slump, slump flow, washout resistance and compressive strength. The compressive strength of each concrete mixture cast underwater was determined at 3, 7, 28 days and compared with the compressive strength of the same concrete mixture cast in normal condition (in air). Test results indicated that the use of an AWA facilitates the production of flow able concrete mixtures with the added benefit of lower washout loss. Concrete mixture proportioned using Type II cement and fly ash at level of replacement of 15% was found to develop self flowing concrete with better fresh and hardened properties and more resistant to washout. The self-flowing underwater concretes developed a 28-day compressive strengths ranging from 20 to 28 MPa

AEKF-SLAM: A New Algorithm for Robotic Underwater Navigation

Directory of Open Access Journals (Sweden)

Xin Yuan

2017-05-01

Full Text Available In this work, we focus on key topics related to underwater Simultaneous Localization and Mapping (SLAM applications. Moreover, a detailed review of major studies in the literature and our proposed solutions for addressing the problem are presented. The main goal of this paper is the enhancement of the accuracy and robustness of the SLAM-based navigation problem for underwater robotics with low computational costs. Therefore, we present a new method called AEKF-SLAM that employs an Augmented Extended Kalman Filter (AEKF-based SLAM algorithm. The AEKF-based SLAM approach stores the robot poses and map landmarks in a single state vector, while estimating the state parameters via a recursive and iterative estimation-update process. Hereby, the prediction and update state (which exist as well in the conventional EKF are complemented by a newly proposed augmentation stage. Applied to underwater robot navigation, the AEKF-SLAM has been compared with the classic and popular FastSLAM 2.0 algorithm. Concerning the dense loop mapping and line mapping experiments, it shows much better performances in map management with respect to landmark addition and removal, which avoid the long-term accumulation of errors and clutters in the created map. Additionally, the underwater robot achieves more precise and efficient self-localization and a mapping of the surrounding landmarks with much lower processing times. Altogether, the presented AEKF-SLAM method achieves reliably map revisiting, and consistent map upgrading on loop closure.

DUMAND-II (Deep Underwater Muon and Neutrino Detector) PROGRESS Report

OpenAIRE

Young, Kenneth K.

1994-01-01

The DUMAND-II detector will search for astronomical sources of high energy neutrinos. Successful deployment of the basic infrastructure, including the shore cable, the underwater junction box, and an environmental module was accomplished in December, 1993. One optical module string was also deployed and operated, logging data for about 10 hours. The underwater cable was connected to the shore station where we were able to successfully exercise system controls and log further environmental dat...

Is a nuclear weapon-free world desirable?

International Nuclear Information System (INIS)

Tertrais, Bruno

2009-01-01

In this article, the author shows that a nuclear weapon-free world would probably be more dangerous than today's world because benefits of the existence of nuclear weapons are probably more important that the risks related to their existence. He outlines that nuclear deterrence has been very efficient for these last 65 years. He states that the disappearance of nuclear weapons could be envisaged only after a large transformation of safety conditions, but that such transformations are actually not at all under way. It would indeed require peaceful and democratic world governance

A Probabilistic and Highly Efficient Topology Control Algorithm for Underwater Cooperating AUV Networks.

Science.gov (United States)

Li, Ning; Cürüklü, Baran; Bastos, Joaquim; Sucasas, Victor; Fernandez, Jose Antonio Sanchez; Rodriguez, Jonathan

2017-05-04

The aim of the Smart and Networking Underwater Robots in Cooperation Meshes (SWARMs) project is to make autonomous underwater vehicles (AUVs), remote operated vehicles (ROVs) and unmanned surface vehicles (USVs) more accessible and useful. To achieve cooperation and communication between different AUVs, these must be able to exchange messages, so an efficient and reliable communication network is necessary for SWARMs. In order to provide an efficient and reliable communication network for mission execution, one of the important and necessary issues is the topology control of the network of AUVs that are cooperating underwater. However, due to the specific properties of an underwater AUV cooperation network, such as the high mobility of AUVs, large transmission delays, low bandwidth, etc., the traditional topology control algorithms primarily designed for terrestrial wireless sensor networks cannot be used directly in the underwater environment. Moreover, these algorithms, in which the nodes adjust their transmission power once the current transmission power does not equal an optimal one, are costly in an underwater cooperating AUV network. Considering these facts, in this paper, we propose a Probabilistic Topology Control (PTC) algorithm for an underwater cooperating AUV network. In PTC, when the transmission power of an AUV is not equal to the optimal transmission power, then whether the transmission power needs to be adjusted or not will be determined based on the AUV's parameters. Each AUV determines their own transmission power adjustment probability based on the parameter deviations. The larger the deviation, the higher the transmission power adjustment probability is, and vice versa. For evaluating the performance of PTC, we combine the PTC algorithm with the Fuzzy logic Topology Control (FTC) algorithm and compare the performance of these two algorithms. The simulation results have demonstrated that the PTC is efficient at reducing the transmission power

A Probabilistic and Highly Efficient Topology Control Algorithm for Underwater Cooperating AUV Networks

Directory of Open Access Journals (Sweden)

Ning Li

2017-05-01

Full Text Available The aim of the Smart and Networking Underwater Robots in Cooperation Meshes (SWARMs project is to make autonomous underwater vehicles (AUVs, remote operated vehicles (ROVs and unmanned surface vehicles (USVs more accessible and useful. To achieve cooperation and communication between different AUVs, these must be able to exchange messages, so an efficient and reliable communication network is necessary for SWARMs. In order to provide an efficient and reliable communication network for mission execution, one of the important and necessary issues is the topology control of the network of AUVs that are cooperating underwater. However, due to the specific properties of an underwater AUV cooperation network, such as the high mobility of AUVs, large transmission delays, low bandwidth, etc., the traditional topology control algorithms primarily designed for terrestrial wireless sensor networks cannot be used directly in the underwater environment. Moreover, these algorithms, in which the nodes adjust their transmission power once the current transmission power does not equal an optimal one, are costly in an underwater cooperating AUV network. Considering these facts, in this paper, we propose a Probabilistic Topology Control (PTC algorithm for an underwater cooperating AUV network. In PTC, when the transmission power of an AUV is not equal to the optimal transmission power, then whether the transmission power needs to be adjusted or not will be determined based on the AUV’s parameters. Each AUV determines their own transmission power adjustment probability based on the parameter deviations. The larger the deviation, the higher the transmission power adjustment probability is, and vice versa. For evaluating the performance of PTC, we combine the PTC algorithm with the Fuzzy logic Topology Control (FTC algorithm and compare the performance of these two algorithms. The simulation results have demonstrated that the PTC is efficient at reducing the

Research on the underwater target imaging based on the streak tube laser lidar

Science.gov (United States)

Cui, Zihao; Tian, Zhaoshuo; Zhang, Yanchao; Bi, Zongjie; Yang, Gang; Gu, Erdan

2018-03-01

A high frame rate streak tube imaging lidar (STIL) for real-time 3D imaging of underwater targets is presented in this paper. The system uses 532nm pulse laser as the light source, the maximum repetition rate is 120Hz, and the pulse width is 8ns. LabVIEW platform is used in the system, the system control, synchronous image acquisition, 3D data processing and display are realized through PC. 3D imaging experiment of underwater target is carried out in a flume with attenuation coefficient of 0.2, and the images of different depth and different material targets are obtained, the imaging frame rate is 100Hz, and the maximum detection depth is 31m. For an underwater target with a distance of 22m, the high resolution 3D image real-time acquisition is realized with range resolution of 1cm and space resolution of 0.3cm, the spatial relationship of the targets can be clearly identified by the image. The experimental results show that STIL has a good application prospect in underwater terrain detection, underwater search and rescue, and other fields.

President Nixon’s Decision to Renounce the U.S. Offensive Biological Weapons Program

Science.gov (United States)

2009-10-01

outreach efforts, the WMD Center hosts annual symposia on key issues bringing together leaders and experts from the government and private sectors ...fever and the virus that causes Venezuelan equine encephalitis); and two types of anticrop weapons (the fungi that cause wheat rust and rice blast...Venezuelan equine encephalitis virus; liquid suspensions of Venezuelan equine encephalitis virus and Q-fever rickettsia; and tens of thousands of

Development of underwater camera using high-definition camera

International Nuclear Information System (INIS)

Tsuji, Kenji; Watanabe, Masato; Takashima, Masanobu; Kawamura, Shingo; Tanaka, Hiroyuki

2012-01-01

In order to reduce the time for core verification or visual inspection of BWR fuels, the underwater camera using a High-Definition camera has been developed. As a result of this development, the underwater camera has 2 lights and 370 x 400 x 328mm dimensions and 20.5kg weight. Using the camera, 6 or so spent-fuel IDs are identified at 1 or 1.5m distance at a time, and 0.3mmφ pin-hole is recognized at 1.5m distance and 20 times zoom-up. Noises caused by radiation less than 15 Gy/h are not affected the images. (author)

Time-of-flight range imaging for underwater applications

Science.gov (United States)

Merbold, Hannes; Catregn, Gion-Pol; Leutenegger, Tobias

2018-02-01

Precise and low-cost range imaging in underwater settings with object distances on the meter level is demonstrated. This is addressed through silicon-based time-of-flight (TOF) cameras operated with light emitting diodes (LEDs) at visible, rather than near-IR wavelengths. We find that the attainable performance depends on a variety of parameters, such as the wavelength dependent absorption of water, the emitted optical power and response times of the LEDs, or the spectral sensitivity of the TOF chip. An in-depth analysis of the interplay between the different parameters is given and the performance of underwater TOF imaging using different visible illumination wavelengths is analyzed.

Reduced Attitude Control of a Robotic Underwater Vehicle

Directory of Open Access Journals (Sweden)

Bláha Lukáš

2017-01-01

Full Text Available This paper deals with stabilization and reduced attitude control of a robotic underwater vehicle. The vehicle is assumed to be able to perform a full stable rotations around all axes in underwater space, that is why the standard bottom-heavy structure is not used. The system preferably uses a vectored-thrust arrangement and is built as an overactuated system, which enables to gain a better robustness and guarantees a stable controlled motion even if some thruster suddenly stop working. Because the heading angle cannot be measured, the reduced attitude control strategy is designed and the stability of reduced state of the system is proved using perturbation method.

Study of underwater laser propulsion using different target materials.

Science.gov (United States)

Qiang, Hao; Chen, Jun; Han, Bing; Shen, Zhong-Hua; Lu, Jian; Ni, Xiao-Wu

2014-07-14

In order to investigate the influence of target materials, including aluminum (Al), titanium (Ti) and copper (Cu), on underwater laser propulsion, the analytical formula of the target momentum IT is deduced from the enhanced coupling theory of laser propulsion in atmosphere with transparent overlay metal target. The high-speed photography method and numerical simulation are employed to verify the IT model. It is shown that the enhanced coupling theory, which was developed originally for laser propulsion in atmosphere, is also applicable to underwater laser propulsion with metal targets.

Environmental effects on underwater optical transmission

Science.gov (United States)

Chu, Peter C.; Breshears, Brian F.; Cullen, Alexander J.; Hammerer, Ross F.; Martinez, Ramon P.; Phung, Thai Q.; Margolina, Tetyana; Fan, Chenwu

2017-05-01

Optical communication/detection systems have potential to get around some limitations of current acoustic communications and detection systems especially increased fleet and port security in noisy littoral waters. Identification of environmental effects on underwater optical transmission is the key to the success of using optics for underwater communication and detection. This paper is to answer the question "What are the transfer and correlation functions that relate measurements of hydrographic to optical parameters?" Hydrographic and optical data have been collected from the Naval Oceanographic Office survey ships with the High Intake Defined Excitation (HIDEX) photometer and sea gliders with optical back scattering sensor in various Navy interested areas such as the Arabian Gulf, Gulf of Oman, east Asian marginal seas, and Adriatic Sea. The data include temperature, salinity, bioluminescence, chlorophyll-a fluorescence, transmissivity at two different wavelengths (TRed at 670 nm, TBlue at 490 nm), and back scattering coefficient (bRed at 700 nm, bBlue at 470 nm). Transfer and correlation functions between the hydrographic and optical parameters are obtained. Bioluminescence and fluorescence maxima, transmissivity minimum with their corresponding depths, red and blue laser beam peak attenuation coefficients are identified from the optical profiles. Evident correlations are found between the ocean mixed layer depth and the blue and red laser beam peak attenuation coefficients, bioluminescence and fluorescence maxima in the Adriatic Sea, Arabian Gulf, Gulf of Oman, and Philippine Sea. Based on the observational data, an effective algorithm is recommended for solving the radiative transfer equation (RTE) for predicting underwater laser radiance.

A Data Link Layer in Support of Swarming of Autonomous Underwater Vehicles

Science.gov (United States)

Jabba Molinares, Daladier

2009-01-01

Communication underwater is challenging because of the inherent characteristics of the media. First, common radio frequency (RF) signals utilized in wireless communications cannot be used under water. RF signals are attenuated in such as way that RF communication underwater is restricted to very few meters. As a result, acoustic-based…

A field guide to valuable underwater aquatic plants of the Great Lakes

Science.gov (United States)

Schloesser, Donald W.

1986-01-01

Underwater plants are a valuable part of the Great Lakes ecosystem, providing food and shelter for aquatic animals. Aquatic plants also help stabilize sediments, thereby reducing shoreline erosion. Annual fall die-offs of underwater plants provide food and shelter for overwintering small aquatic animals such as insects, snails, and freshwater shrimp.

Game Theory-Based Cooperation for Underwater Acoustic Sensor Networks: Taxonomy, Review, Research Challenges and Directions.

Science.gov (United States)

Muhammed, Dalhatu; Anisi, Mohammad Hossein; Zareei, Mahdi; Vargas-Rosales, Cesar; Khan, Anwar

2018-02-01

Exploring and monitoring the underwater world using underwater sensors is drawing a lot of attention these days. In this field cooperation between acoustic sensor nodes has been a critical problem due to the challenging features such as acoustic channel failure (sound signal), long propagation delay of acoustic signal, limited bandwidth and loss of connectivity. There are several proposed methods to improve cooperation between the nodes by incorporating information/game theory in the node's cooperation. However, there is a need to classify the existing works and demonstrate their performance in addressing the cooperation issue. In this paper, we have conducted a review to investigate various factors affecting cooperation in underwater acoustic sensor networks. We study various cooperation techniques used for underwater acoustic sensor networks from different perspectives, with a concentration on communication reliability, energy consumption, and security and present a taxonomy for underwater cooperation. Moreover, we further review how the game theory can be applied to make the nodes cooperate with each other. We further analyze different cooperative game methods, where their performance on different metrics is compared. Finally, open issues and future research direction in underwater acoustic sensor networks are highlighted.

Game Theory-Based Cooperation for Underwater Acoustic Sensor Networks: Taxonomy, Review, Research Challenges and Directions

Directory of Open Access Journals (Sweden)

Dalhatu Muhammed

2018-02-01

Full Text Available Exploring and monitoring the underwater world using underwater sensors is drawing a lot of attention these days. In this field cooperation between acoustic sensor nodes has been a critical problem due to the challenging features such as acoustic channel failure (sound signal, long propagation delay of acoustic signal, limited bandwidth and loss of connectivity. There are several proposed methods to improve cooperation between the nodes by incorporating information/game theory in the node’s cooperation. However, there is a need to classify the existing works and demonstrate their performance in addressing the cooperation issue. In this paper, we have conducted a review to investigate various factors affecting cooperation in underwater acoustic sensor networks. We study various cooperation techniques used for underwater acoustic sensor networks from different perspectives, with a concentration on communication reliability, energy consumption, and security and present a taxonomy for underwater cooperation. Moreover, we further review how the game theory can be applied to make the nodes cooperate with each other. We further analyze different cooperative game methods, where their performance on different metrics is compared. Finally, open issues and future research direction in underwater acoustic sensor networks are highlighted.

Game Theory-Based Cooperation for Underwater Acoustic Sensor Networks: Taxonomy, Review, Research Challenges and Directions

Science.gov (United States)

Muhammed, Dalhatu; Anisi, Mohammad Hossein; Vargas-Rosales, Cesar; Khan, Anwar

2018-01-01

Exploring and monitoring the underwater world using underwater sensors is drawing a lot of attention these days. In this field cooperation between acoustic sensor nodes has been a critical problem due to the challenging features such as acoustic channel failure (sound signal), long propagation delay of acoustic signal, limited bandwidth and loss of connectivity. There are several proposed methods to improve cooperation between the nodes by incorporating information/game theory in the node’s cooperation. However, there is a need to classify the existing works and demonstrate their performance in addressing the cooperation issue. In this paper, we have conducted a review to investigate various factors affecting cooperation in underwater acoustic sensor networks. We study various cooperation techniques used for underwater acoustic sensor networks from different perspectives, with a concentration on communication reliability, energy consumption, and security and present a taxonomy for underwater cooperation. Moreover, we further review how the game theory can be applied to make the nodes cooperate with each other. We further analyze different cooperative game methods, where their performance on different metrics is compared. Finally, open issues and future research direction in underwater acoustic sensor networks are highlighted. PMID:29389874

CFD Based Added Mass Prediction in Cruise Condition of Underwater Vehicle Dynamic

Science.gov (United States)

Agoes Moelyadi, Mochammad; Bambang Riswandi, Bagus

2018-04-01

One of the unsteady flow behavior on the hydrodynamic characteristics of underwater vehicle is the presence of added mass. In cruising conditions, the underwater vehicle may require the addition of speed or experience the disturbance in the form of unsteady flow so that cause the hydrodynamic interaction between the surface of the vehicle with the surrounding fluid. This leads to the rise of local velocity of flow and the great changes of hydrodynamic forces which are very influential on the stability of the underwater vehicle. One of the result is an additional force called added mass. It is very useful parameter to control underwater vehicle dynamic.This paper reports the research on the added mass coefficient of underwater vehicles obtained through the Computational Fluid Dynmaic (CFD) simulation method using CFX software. Added mass coefficient is calculated by performing an unsteady simulation or known as transient simulation. Computational simulations are based on the Reynold Average Navier- Stokes (RANS) equation solution. The simulated vehicle moves forward and backward according to the sinus function, with a frequency of 0.25 Hz, a 2 m amplitude, a cruising depth of 10 m below sea level, and Vcruise 1.54 m / s (Re = 9.000.000). Simulation result data includes velocity contour, variation of force and acceleration to frequency, and added mass coefficient.

Priority Determination of Underwater Tourism Site Development in Gorontalo Province using Analytical Hierarchy Process (AHP)

Science.gov (United States)

Rohandi, M.; Tuloli, M. Y.; Jassin, R. T.

2018-02-01

This research aims to determine the development of priority of underwater tourism in Gorontalo province using the Analytical Hierarchy Process (AHP) method which is one of DSS methods applying Multi-Attribute Decision Making (MADM). This method used 5 criteria and 28 alternatives to determine the best priority of underwater tourism site development in Gorontalo province. Based on the AHP calculation it appeared that the best priority development of underwater tourism site is Pulau Cinta whose total AHP score is 0.489 or 48.9%. This DSS produced a reliable result, faster solution, time-saving, and low cost for the decision makers to obtain the best underwater tourism site to be developed.

Islamic State and Chemical Weapons

Directory of Open Access Journals (Sweden)

Lukáš Rafay

2016-09-01

Full Text Available The article deals with topic of Islamic State and chemical weapons. The issue is analysed in three dimensions: origin of used chemical weapons and possibility of independent production; known chemical attacks and tactical regularities in their execution; and traits of future chemical terrorist attacks. By providing a thorough examination of the problem, the article aims at predicting the future development of the group’s chemical program as well as describing any prospective chemical terrorist attacks in Europe

SEATURTLE: Sustained Engagement Autonomous Tracking of Underwater RepTiLEs

OpenAIRE

Budd, Johnathan

2015-01-01

While oceans cover the majority of our planet, these vast expanses remain relatively unexplored. Among the most interesting parts of the ocean are the shallow reef systems, which contain a huge amount of the planet’s biodiversity. The Sustained Engagement Autonomous Tracking of Underwater RepTiLEs or SEATURTLE is a low cost Autonomous Underwater Vehicle designed to carry out missions in these shallow environments. Its small displacement and precise movement make it ideal for navigating tight ...

Nuclear weapons in Europe

International Nuclear Information System (INIS)

Pierre, A.J.

1984-01-01

In this introduction to ''Nuclear Weapons in Europe'', the author summarized the views of two Americans and two Europeans, whose articles make up the volume. The introduction explains the different assumptions of the four authors before discussing their views on the military and political rationales for a nuclear force in the North Atlantic Treaty Organization (NATO) and the debate over battlefield nuclear weapons, conventional defense, and arms control proposals and talks. The four contributors whose views are analyzed are William G. Hyland, Lawrence D. Freeman, Paul C. Warnke, and Karstan D. Voight. The introduction notes that the agreements and differences do not fall strictly on American versus European dividing lines

The medical consequences of nuclear weapons

International Nuclear Information System (INIS)

Humphrey, J.; Hartog, M.; Middleton, H.

1982-01-01

A pamphlet has been produced by the Medical Campaign Against Nuclear Weapons (MCANW) and by the Medical Association for the Prevention of War (MAPW) to bring the catastrophic effects that the use of nuclear weapons would entail to the attention of the general public, politicians and members of the medical profession. It describes the medical consequences of the effects of blast, heat and ionizing radiation from nuclear weapons, including details from the Hiroshima and Nagasaki atomic bombings. The medical consequences of a nuclear attack including consideration of the casualties, care of the injured, psychological effects and the outcome are also discussed. It is concluded that if for none other than purely medical reasons, nuclear warfare must never be allowed to happen. (UK)

A Wide Area Risk Assessment Framework for Underwater Military Munitions Response

Science.gov (United States)

Holland, K. T.; Calantoni, J.

2017-12-01

Our objective was to develop a prototype statistical framework supporting Wide Area Assessment and Remedial Investigation decisions relating to the risk of unexploded ordnance and other military munitions concentrated in underwater environments. Decision making involving underwater munitions is inherently complex due to the high degree of uncertainty in the environmental conditions that force munitions responses (burial, decay, migration, etc.) and associated risks to the public. The prototype framework provides a consistent approach to accurately delineating contaminated areas at underwater munitions sites through the estimation of most probable concentrations. We adapted existing deterministic models and environmental data services for use within statistical modules that allowed the estimation of munition concentration given historic site information and environmental attributes. Ultimately this risk surface can be used to evaluate costs associated with various remediation approaches (e.g. removal, monitoring, etc.). Unfortunately, evaluation of the assessment framework was limited due to the lack of enduser data services from munition site managers. Of the 450 U.S. sites identified as having potential contamination with underwater munitions, assessment of available munitions information (including historic firing or disposal records, and recent ground-truth munitions samples) indicated very limited information in the databases. Example data types include the most probable munition types, approximate firing / disposal dates and locations, and any supportive munition survey or sampling results. However the overall technical goal to integrate trained statistical belief networks with detailed geophysical knowledge of sites, of sensors and of the underwater environment was demonstrated and should allow probabilistic estimates of the most likely outcomes and tradeoffs while managing uncertainty associated with military munitions response.

Space weapon technology and policy

Science.gov (United States)

Hitchens, Theresa

2017-11-01

The military use of space, including in support of nuclear weapons infrastructure, has greatly increased over the past 30 years. In the current era, rising geopolitical tensions between the United States and Russia and China have led to assumptions in all three major space powers that warfighting in space now is inevitable, and possible because of rapid technological advancements. New capabilities for disrupting and destroying satellites include radio-frequency jamming, the use of lasers, maneuverable space objects and more capable direct-ascent anti-satellite weapons. This situation, however, threatens international security and stability among nuclear powers. There is a continuing and necessary role for diplomacy, especially the establishment of normative rules of behavior, to reduce risks of misperceptions and crisis escalation, including up to the use of nuclear weapons. U.S. policy and strategy should seek a balance between traditional military approaches to protecting its space assets and diplomatic tools to create a more secure space environment.

The nuclear weapon; L'arme nucleaire

Energy Technology Data Exchange (ETDEWEB)

Tertrais, Bruno

2008-07-01

The author presents the technology, the concept of deterrence, the today means and the international control, concerning the nuclear weapon. The conclusion is pessimistic. The author sees only two issues: the substitution of a new weapon more powerful, or its use. (A.L.B.)

Validation of Underwater Sensor Package Using Feature Based SLAM

Directory of Open Access Journals (Sweden)

Christopher Cain

2016-03-01

Full Text Available Robotic vehicles working in new, unexplored environments must be able to locate themselves in the environment while constructing a picture of the objects in the environment that could act as obstacles that would prevent the vehicles from completing their desired tasks. In enclosed environments, underwater range sensors based off of acoustics suffer performance issues due to reflections. Additionally, their relatively high cost make them less than ideal for usage on low cost vehicles designed to be used underwater. In this paper we propose a sensor package composed of a downward facing camera, which is used to perform feature tracking based visual odometry, and a custom vision-based two dimensional rangefinder that can be used on low cost underwater unmanned vehicles. In order to examine the performance of this sensor package in a SLAM framework, experimental tests are performed using an unmanned ground vehicle and two feature based SLAM algorithms, the extended Kalman filter based approach and the Rao-Blackwellized, particle filter based approach, to validate the sensor package.

Validation of Underwater Sensor Package Using Feature Based SLAM

Science.gov (United States)

Cain, Christopher; Leonessa, Alexander

2016-01-01

Robotic vehicles working in new, unexplored environments must be able to locate themselves in the environment while constructing a picture of the objects in the environment that could act as obstacles that would prevent the vehicles from completing their desired tasks. In enclosed environments, underwater range sensors based off of acoustics suffer performance issues due to reflections. Additionally, their relatively high cost make them less than ideal for usage on low cost vehicles designed to be used underwater. In this paper we propose a sensor package composed of a downward facing camera, which is used to perform feature tracking based visual odometry, and a custom vision-based two dimensional rangefinder that can be used on low cost underwater unmanned vehicles. In order to examine the performance of this sensor package in a SLAM framework, experimental tests are performed using an unmanned ground vehicle and two feature based SLAM algorithms, the extended Kalman filter based approach and the Rao-Blackwellized, particle filter based approach, to validate the sensor package. PMID:26999142

L2-LBMT: A Layered Load Balance Routing Protocol for underwater multimedia data transmission

Science.gov (United States)

Lv, Ze; Tang, Ruichun; Tao, Ye; Sun, Xin; Xu, Xiaowei

2017-12-01

Providing highly efficient underwater transmission of mass multimedia data is challenging due to the particularities of the underwater environment. Although there are many schemes proposed to optimize the underwater acoustic network communication protocols, from physical layer, data link layer, network layer to transport layer, the existing routing protocols for underwater wireless sensor network (UWSN) still cannot well deal with the problems in transmitting multimedia data because of the difficulties involved in high energy consumption, low transmission reliability or high transmission delay. It prevents us from applying underwater multimedia data to real-time monitoring of marine environment in practical application, especially in emergency search, rescue operation and military field. Therefore, the inefficient transmission of marine multimedia data has become a serious problem that needs to be solved urgently. In this paper, A Layered Load Balance Routing Protocol (L2-LBMT) is proposed for underwater multimedia data transmission. In L2-LBMT, we use layered and load-balance Ad Hoc Network to transmit data, and adopt segmented data reliable transfer (SDRT) protocol to improve the data transport reliability. And a 3-node variant of tornado (3-VT) code is also combined with the Ad Hoc Network to transmit little emergency data more quickly. The simulation results show that the proposed protocol can balance energy consumption of each node, effectively prolong the network lifetime and reduce transmission delay of marine multimedia data.

Find and neutralize clandestine nuclear weapons

International Nuclear Information System (INIS)

Canavan, G.H.

1997-09-01

The objective of finding nuclear material at entry portals is to provide a secure perimeter as large as a weapon damage radius so that operations could be conducted within it relatively unencumbered. The objective of wide area search for nuclear material to provide a safe zone of similar dimensions in an area in which it is not possible to maintain a secure perimeter, to provide assurance for civilians living at an area at risk, or to provide rapid, wide area search of regions that could conceal nuclear threats to forces in the field. This rapid, wide-area, and confident detection of nuclear materials is the essential first step in developing the ability to negate terrorist nuclear assemblies or weapons. The ability to detect and negate nuclear materials are necessary to prevent the forced, massive evacuation of urban populations or the disruption of military operations in response to terrorist threats. This paper describes the limitations to current sensors used for nuclear weapon detection and discusses a novel approach to nuclear weapon detection using a combination of directional information (imaging) and gamma ray energy (color) to produce a gamma ray color camera

Towards the complete prohibition and elimination of nuclear weapons

International Nuclear Information System (INIS)

Xie Zhiqiong

1998-01-01

For 40 years, the Pugwash Conference on Science and world affairs has been making unremitting efforts to achieve it main objectives the struggle to eliminate nuclear weapons, the elimination of wars and maintenance of world peace. The end of the Cold War vigorously encouraged world efforts in arms control and disarmament. On the day of exploding her first nuclear bomb in October 1964, China declared solemnly that it would never be the first to use nuclear weapons at any time under any circumstances. China has also committed unconditionally not to use nuclear weapons or threaten to use nuclear weapons against non-nuclear weapon states and nuclear free zones. China is the sole nuclear weapon state that has made this commitment, and she has kept her word. China is in favour of comprehensive nuclear test ban in the move towards complete nuclear disarmament, taking an active part in the CTBT negotiations in Geneva and contributing to the conclusion of a fair, reasonable, verifiable treaty of universal adherence and unlimited duration within this year

Modelling of the underwater disposal of uranium mine tailings in Elliot Lake

International Nuclear Information System (INIS)

Halbert, B.E.; Scharer, J.M.; Chakravatti, J.L.; Barnes, E.

1982-01-01

Underwater disposal of uranium mine tailings from the Elliot Lake area operations offers potential advantages in controlling radon gas release, emission of airborne particulate matter, and acid production from pyrites in the tailings. In addition, the proximity of the three active properties, one owned by Denison Mines Limited and two by Rio Algom Limited, to a large deep lake has spurred interest in the concept. It has been estimated that the placement of approximately 150 million tonnes of tailings from future planned production would occupy less than 20% of the lake volume. To assess the applicability of the underwater tailings disposal concept, a multi-stage study was developed in conjunction with the regulatory agencies. The most important facet identified for investigation during the first-stage investigations was an assessment of the effects of underwater disposal on water quality in the Serpent River Basin watershed. To simulate the effects of underwater disposal, a computer simulation routine was developed and integrated with a water quality model previously developed for the Basin which predicts levels of total dissolved solids, ammonia, dissolved radium-226 and pH. The underwater disposal model component reflects the effects of direct input of tailings into the hypolimnion, the chemical/biological transformation of dissolved constituents in the water column, the reactions of pyritic tailings deposited on the bottom, and the flux of dissolved constituents from the tailings into the water column. To establish site-specific values for the underwater disposal model, field and laboratory experiments were utilized to evaluate rates of pyrite and ammonia oxidation, and pH-alkalinity relationships. The results of these studies and their use in the water quality model are discussed. In addition, the results of two model run simulations are presented. (author)

Long term effects of chemical weapons on health in Kurdistan of Iraq

International Nuclear Information System (INIS)

Dizaye, K.

2009-01-01

Extensive exposure to chemical weapons such as mustard gas, nerve gas and cyanide caused high mortality, morbidity, injuries, and chronic side effects in vital organs, especially the respiratory tract. Chemical weapons were heavily used by Iraq against Iranian soldiers between 1984-1986. Then, against the Iraqi Kurd in Sheikh Wasan and Balisan valley, during April 1987 and in Halabja on 18th March 1988. Reports suggested that as many as 2.9 percent of the Kurdish population have been exposed to chemical weapon at some level. This case report describes a Kurdish lady who was exposed to mustard gas during a chemical attack in sheikh Wasan in Iraq. A thirty two years old woman wearing black clothes presented to our center at 1999 complaining from shortness of breath (SOB). Her condition started 12 years ago when the Iraqi Government attacked her village Sheikh Wasan by Chemical weapons which included Mustard gas and nerve gases such as Sarin, Tabun and VX in April 1987. She described how the gas smelled like garlic as it spread over the village. During the attack she suffered from sever SOB, cough, skin burn and eyes irritation and lacrimation. After several days of being without medical care, she received some medical attention by local medical staff at the area because the Iraqi authorities at that time refused and prohibited them from management at the major hospitals. After several days when she returned back to her home she found that several members of her family have died during the exposure to chemical gases. Among the dead people were her husband, her son, her brother in addition to other second and third degree relatives. Since that time she suffered from repeated attacks of cough and SOB and wheezing that were increased by exertion and cold exposure. The attacks were more sever with time and the SOB has interfered with her daily activity and even lastly she was suffering from SOB at rest and during sleep that made her unable to sleep lying down. Moreover

Color image fusion for concealed weapon detection

NARCIS (Netherlands)

Toet, A.

2003-01-01

Recent advances in passive and active imaging sensor technology offer the potential to detect weapons that are concealed underneath a person's clothing or carried along in bags. Although the concealed weapons can sometimes easily be detected, it can be difficult to perceive their context, due to the

Foreign trade legislation, war weapons control legislation

International Nuclear Information System (INIS)

Hucko, E.M.

1993-01-01

The volume contains, in addition to an introduction into the matter, the texts of the Foreign Trade Act (FTA), the War Weapons Control Act and all relevant ordinances. Foreign trade transactions of the Federal Republic of Germany are essentially, but not exclusively, governed by the FTA. They are strongly influenced by the legislation of the European Communities which in the form of directives are immediately effective here, and in the form of guidelines oblige the German lawgiver or ordinance giver to translate them into practice, mostly by appropriate modifications of the foreign trade ordinance, the import and export lists. It is not the war weapons which are the problem, but the so-called dual-use goods, namely articles, technologies and knowledge which, as a rule, serve civil purposes, which, however, may be used also to produce weapons, in particular ABC weapons or rockets. Nowadays we are concerned about several third-world states which are obsessed by the wish to build their own atomic bomb. (orig./HSCH) [de

Oil and influence: the oil weapon examined

Energy Technology Data Exchange (ETDEWEB)

Maull, H

1975-01-01

The term ''oil weapon'' as used here signifies any manipulation of the price and/or supply of oil by exporting nations with the intention of changing the political behavior of the consumer nations. The political potential of the oil price is fairly restricted so, in effect, the supply interruptions are of prime concern. Manipulating price does, in principle, offer the possibilities of both conferring rewards and inflicting sanctions. Oil could be sold on preferential prices and terms. A precondition for using the oil weapon successfully would be the ability to cause real and serious damage to the consumer countries. Four damaging potentials for using the oil weapon could include its application by: (1) one producer against one consumer; (2) one producer against all consumers; (3) a group of producers against one consumer; and (4) by a group of producers against all consumers. It is concluded that the oil weapon will continue to be a force in the international system. (MCW)

System and Method for Automated Rendezvous, Docking and Capture of Autonomous Underwater Vehicles

Science.gov (United States)

Stone, William C. (Inventor); Clark, Evan (Inventor); Richmond, Kristof (Inventor); Paulus, Jeremy (Inventor); Kapit, Jason (Inventor); Scully, Mark (Inventor); Kimball, Peter (Inventor)

2018-01-01

A system for automated rendezvous, docking, and capture of autonomous underwater vehicles at the conclusion of a mission comprising of comprised of a docking rod having lighted, pulsating (in both frequency and light intensity) series of LED light strips thereon, with the LEDs at a known spacing, and the autonomous underwater vehicle specially designed to detect and capture the docking rod and then be lifted structurally by a spherical end strop about which the vehicle can be pivoted and hoisted up (e.g., onto a ship). The method of recovery allows for very routine and reliable automated recovery of an unmanned underwater asset.

Ireland and the UNESCO Convention on the Protection of the Underwater Cultural Heritage

Science.gov (United States)

Kirwan, Seán

2010-12-01

Ratification by Ireland of the 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage will not be able to take place until after enactment of additional domestic legislation. The reasons for this are examined in the context of Ireland's legal system. Since 1987 Ireland has had extensive legal protection for underwater cultural heritage, but the jurisdictional aspects of the Convention are key to understanding why additional legislation is necessary. Issues relating to salvage law are also considered. The 2001 Convention is placed in the context of development of Irish policy on underwater cultural heritage.

Structural adaptations to diverse fighting styles in sexually selected weapons.

Science.gov (United States)

McCullough, Erin L; Tobalske, Bret W; Emlen, Douglas J

2014-10-07

The shapes of sexually selected weapons differ widely among species, but the drivers of this diversity remain poorly understood. Existing explanations suggest weapon shapes reflect structural adaptations to different fighting styles, yet explicit tests of this hypothesis are lacking. We constructed finite element models of the horns of different rhinoceros beetle species to test whether functional specializations for increased performance under species-specific fighting styles could have contributed to the diversification of weapon form. We find that horns are both stronger and stiffer in response to species-typical fighting loads and that they perform more poorly under atypical fighting loads, which suggests weapons are structurally adapted to meet the functional demands of fighting. Our research establishes a critical link between weapon form and function, revealing one way male-male competition can drive the diversification of animal weapons.

Nuclear Weapons and U.S. National Security: A Need for Weapons Programs?

National Research Council Canada - National Science Library

Woolf, Amy F

2003-01-01

.... nuclear weapons that goes beyond the concept of deterrence from the Cold War. It also identified a new targeting strategy that would seek to threaten specific capabilities in adversary nations...

H∞ control of a remotely operated underwater vehicle

International Nuclear Information System (INIS)

Conte, G.; Serrani, A.

1994-01-01

The paper discusses the application of H∞ control techniques to the design of a control system for a remotely operated underwater vehicle. As the main problem in defining a control strategy for such vehicles is the nonlinear and uncertain nature of the modeled dynamics, the robustness properties of H∞ controllers can in principle be used to provide stability and nominal performances for the closed loop system. Therefore, a control strategy based on a scheduling of such controllers has been proposed, and the overall performance of the closed loop system have been evaluated by means of nonlinear simulation in a broad range of working conditions, with particular attention to the effects of the underwater current that acts on the vehicle

High-Energy Laser Weapon Integration with Ground Vehicles

National Research Council Canada - National Science Library

Hafften, Michael; Stratton, Robert

2004-01-01

.... The architecture of an electric, solid-state HEL weapon system would likely be based upon a hybrid electric vehicle that provides a common electrical power source for the propulsion and weapon subsystems...

From weapons to waste: The future of the nuclear weapons complex

International Nuclear Information System (INIS)

Wasserman Goodman, Sherri

1992-01-01

This paper examines how decision-making power has shifted within the nuclear weapons complex, from the federal government operating agency, in which power was originally vested by the Atomic Energy Act, to the states and to regulatory authorities. Additionally, when the original operating agency, the Atomic Energy Commission (AEC), was abolished in the 1970s, substantial decision-making power shifted from Washington to the field sites. This paper identifies the needs for future materials and weapons production, and recommends that restart of old plants be abandoned as no longer militarily necessary. Instead, the U. S. should take advantage of what may be a unique opportunity to 'leapfrog' to new, smaller, technologically-advanced plants that will meet the needs of the nuclear arsenal in the post-Cold War world. This paper then looks at the current state of DOE's environmental restoration/waste management program, and the technological, legal and political problems it faces in trying to accomplish its mission of cleaning up all nuclear weapons sites. This paper argues that the U. S. government no longer has the exclusive authority to make and carry out critical decisions affecting a cleanup program that will cost the U. S. over $200 billion over the next 20-40 years. Moreover, there are competing theories about the principles that should guide the cleanup program. Finally, the author examines alternative futures for the DOE'S environmental restoration/waste management program. (author)

Open-area concealed-weapon detection system

Science.gov (United States)

Pati, P.; Mather, P.

2011-06-01

Concealed Weapon Detection (CWD) has become a significant challenge to present day security needs; individuals carrying weapons into airplanes, schools, and secured establishments are threat to public security. Although controlled screening, of people for concealed weapons, has been employed in many establishments, procedures and equipment are designed to work in restricted environments like airport passport control, military checkpoints, hospitals, school and university entrance. Furthermore, screening systems do not effectively decipher between threat and non-threat metal objects, thus leading to high rate of false alarms which can become a liability to daily operational needs of establishments. Therefore, the design and development of a new CWD system to operate in a large open area environment with large numbers of people reduced incidences of false alarms and increased location accuracy is essential.

Worldwide governmental efforts to locate and destroy chemical weapons and weapons materials: minimizing risk in transport and destruction.

Science.gov (United States)

Trapp, Ralf

2006-09-01

The article gives an overview on worldwide efforts to eliminate chemical weapons and facilities for their production in the context of the implementation of the 1997 Chemical Weapons Convention (CWC). It highlights the objectives of the Organisation for the Prohibition of Chemical Weapons (OPCW), the international agency set up in The Hague to implement the CWC, and provides an overview of the present status of implementation of the CWC requirements with respect to chemical weapons (CW) destruction under strict international verification. It addresses new requirements that result from an increased threat that terrorists might attempt to acquire or manufacture CW or related materials. The article provides an overview of risks associated with CW and their elimination, from storage or recovery to destruction. It differentiates between CW in stockpile and old/abandoned CW, and gives an overview on the factors and key processes that risk assessment, management, and communication need to address. This discussion is set in the overall context of the CWC that requires the completion of the destruction of all declared CW stockpiles by 2012 at the latest.

Simulation of the behavior of pressurized underwater concrete

Directory of Open Access Journals (Sweden)

Ashraf Mohamed Heniegal

2015-06-01

Full Text Available Under-Water Concrete (UWC contains Anti-Washout Admixtures (AWA (0.0%, 0.2%, 0.3%, 0.4% and 0.5% by weight of cement with cement contents (400, 450, 500 and 550 kg/m3. All concrete mix contains silica fume and high-range water reducing (15% and 4% respectively by weight of cement. The fine to steel slag coarse aggregate was 1:1. The concrete mix was tested for slump, slump flow, compressive strength and washout resistance using two test methods based on different principles. The first method is the plunge test CRDC61 which is widely used in North America, and the second method is the pressurized air tube which has been manufactured for this research and developed to simulate the effect of water pressure on washout resistance of underwater mix. The results of compressive strength test were compared to concrete cast underwater with that cast in air. Test results indicated that the use of an AWA facilitates the production of UWC mix with the added benefit of lower washout resistance. New technique of simulating pressurized UWC is reliable for detecting UWC properties. Adding AWA (0.3–0.5% by weight of cement makes all mix acceptable according to Japanese Society of Civil Engineers.

Cognitive Routing in Software-Defined Underwater Acoustic Networks

Directory of Open Access Journals (Sweden)

Huma Ghafoor

2017-12-01

Full Text Available There are two different types of primary users (natural acoustic and artificial acoustic, and there is a long propagation delay for acoustic links in underwater cognitive acoustic networks (UCANs. Thus, the selection of a stable route is one of the key design factors for improving overall network stability, thereby reducing end-to-end delay. Software-defined networking (SDN is a novel approach that improves network intelligence. To this end, we propose a novel SDN-based routing protocol for UCANs in order to find a stable route between source and destination. A main controller is placed in a surface buoy that is responsible for the global view of the network, whereas local controllers are placed in different autonomous underwater vehicles (AUVs that are responsible for a localized view of the network. The AUVs have fixed trajectories, and sensor nodes within transmission range of the AUVs serve as gateways to relay the gathered information to the controllers. This is an SDN-based underwater communications scheme whereby two nodes can only communicate when they have a consensus about a common idle channel. To evaluate our proposed scheme, we perform extensive simulations and improve network performance in terms of end-to-end delay, delivery ratio, and overhead.

Multibeam 3D Underwater SLAM with Probabilistic Registration

Directory of Open Access Journals (Sweden)

Albert Palomer

2016-04-01

Full Text Available This paper describes a pose-based underwater 3D Simultaneous Localization and Mapping (SLAM using a multibeam echosounder to produce high consistency underwater maps. The proposed algorithm compounds swath profiles of the seafloor with dead reckoning localization to build surface patches (i.e., point clouds. An Iterative Closest Point (ICP with a probabilistic implementation is then used to register the point clouds, taking into account their uncertainties. The registration process is divided in two steps: (1 point-to-point association for coarse registration and (2 point-to-plane association for fine registration. The point clouds of the surfaces to be registered are sub-sampled in order to decrease both the computation time and also the potential of falling into local minima during the registration. In addition, a heuristic is used to decrease the complexity of the association step of the ICP from O ( n 2 to O ( n . The performance of the SLAM framework is tested using two real world datasets: First, a 2.5D bathymetric dataset obtained with the usual down-looking multibeam sonar configuration, and second, a full 3D underwater dataset acquired with a multibeam sonar mounted on a pan and tilt unit.

Underwater Electromagnetic Sensor Networks—Part I: Link Characterization

Directory of Open Access Journals (Sweden)

Gara Quintana-Díaz

2017-01-01

Full Text Available Underwater Wireless Sensor Networks (UWSNs using electromagnetic (EM technology in marine shallow waters are examined, not just for environmental monitoring but for further interesting applications. Particularly, the use of EM waves is reconsidered in shallow waters due to the benefits offered in this context, where acoustic and optical technologies have serious disadvantages. Sea water scenario is a harsh environment for radiocommunications, and there is no standard model for the underwater EM channel. The high conductivity of sea water, the effect of seabed and the surface make the behaviour of the channel hard to predict. This justifies the need of link characterization as the first step to approach the development of EM underwater sensor networks. To obtain a reliable link model, measurements and simulations are required. The measuring setup for this purpose is explained and described, as well as the procedures used. Several antennas have been designed and tested in low frequency bands. Agreement between attenuation measurements and simulations at different distances was analysed and made possible the validation of simulation setups and the design of different communications layers of the system. This leads to the second step of this work, where data and routing protocols for the sensor network are examined.

The Research of Optical Turbulence Model in Underwater Imaging System

Directory of Open Access Journals (Sweden)

Liying Sun

2014-01-01

Full Text Available In order to research the effect of turbulence on underwater imaging system and image restoration, the underwater turbulence model is simulated by computer fluid dynamics. This model is obtained in different underwater turbulence intensity, which contains the pressure data that influences refractive index distribution. When the pressure value is conversed to refractive index, the refractive index distribution can be received with the refraction formula. In the condition of same turbulent intensity, the distribution of refractive index presents gradient in the whole region, with disorder and mutations in the local region. With the turbulence intensity increase, the holistic variation of the refractive index in the image is larger, and the refractive index change more tempestuously in the local region. All the above are illustrated by the simulation results with he ray tracing method and turbulent refractive index model. According to different turbulence intensity analysis, it is proved that turbulence causes image distortion and increases noise.

H∞ control for path tracking of autonomous underwater vehicle motion

Directory of Open Access Journals (Sweden)

Lin-Lin Wang

2015-05-01

Full Text Available In order to simplify the design of path tracking controller and solve the problem relating to nonlinear dynamic model of autonomous underwater vehicle motion planning, feedback linearization method is first adopted to transform the nonlinear dynamic model into an equivalent pseudo-linear dynamic model in horizontal coordinates. Then considering wave disturbance effect, mixed-sensitivity method of H∞ robust control is applied to design state-feedback controller for this equivalent dynamic model. Finally, control law of pseudo-linear dynamic model is transformed into state (surge velocity and yaw angular rate tracking control law of nonlinear dynamic model through inverse coordinate transformation. Simulation indicates that autonomous underwater vehicle path tracking is successfully implemented with this proposed method, and the influence of parameter variation in autonomous underwater vehicle dynamic model on its tracking performance is reduced by H∞ controller. All the results show that the method proposed in this article is effective and feasible.

Nuclear Weapons Enterprise Transformation - A Sustainable Approach

International Nuclear Information System (INIS)

O'Brien, K H

2005-01-01

Nuclear weapons play an essential role in United States (U.S.) National Security Policy and a succession of official reviews has concluded that nuclear weapons will continue to have a role for the foreseeable future. Under the evolving U.S. government policy, it is clear that role will be quite different from what it was during the Cold War. The nuclear-weapons stockpile as well as the nuclear-weapons enterprise needs to continue to change to reflect this evolving role. Stockpile reductions in the early 1990s and the Stockpile Stewardship Program (SSP), established after the cessation of nuclear testing in 1992, began this process of change. Further evolution is needed to address changing security environments, to enable further reductions in the number of stockpiled weapons, and to create a nuclear enterprise that is cost effective and sustainable for the long term. The SSP has successfully maintained the U.S. nuclear stockpile for more than a decade, since the end of nuclear testing. Current plans foresee maintaining warheads produced in the 1980s until about 2040. These warheads continue to age and they are expensive to refurbish. The current Life Extension Program plans for these legacy warheads are straining both the nuclear-weapons production and certification infrastructure making it difficult to respond rapidly to problems or changes in requirements. Furthermore, refurbishing and preserving Cold-War-era nuclear weapons requires refurbishing and preserving an infrastructure geared to support old technology. Stockpile Stewardship could continue this refurbishment approach, but an alternative approach could be considered that is more focused on sustainable technologies, and developing a more responsive nuclear weapons infrastructure. Guided by what we have learned from SSP during the last decade, the stewardship program can be evolved to address this increasing challenge using its computational and experimental tools and capabilities. This approach must start

Underwater Image Enhancement by Adaptive Gray World and Differential Gray-Levels Histogram Equalization

Directory of Open Access Journals (Sweden)

WONG, S.-L.

2018-05-01

Full Text Available Most underwater images tend to be dominated by a single color cast. This paper presents a solution to remove the color cast and improve the contrast in underwater images. However, after the removal of the color cast using Gray World (GW method, the resultant image is not visually pleasing. Hence, we propose an integrated approach using Adaptive GW (AGW and Differential Gray-Levels Histogram Equalization (DHE that operate in parallel. The AGW is applied to remove the color cast while DHE is used to improve the contrast of the underwater image. The outputs of both chromaticity components of AGW and intensity components of DHE are combined to form the enhanced image. The results of the proposed method are compared with three existing methods using qualitative and quantitative measures. The proposed method increased the visibility of underwater images and in most cases produces better quantitative scores when compared to the three existing methods.

Motion analysis and trials of the deep sea hybrid underwater glider Petrel-II

Science.gov (United States)

Liu, Fang; Wang, Yan-hui; Wu, Zhi-liang; Wang, Shu-xin

2017-03-01

A hybrid underwater glider Petrel-II has been developed and field tested. It is equipped with an active buoyancy unit and a compact propeller unit. Its working modes have been expanded to buoyancy driven gliding and propeller driven level-flight, which can make the glider work in strong currents, as well as many other complicated ocean environments. Its maximal gliding speed reaches 1 knot and the propelling speed is up to 3 knots. In this paper, a 3D dynamic model of Petrel-II is derived using linear momentum and angular momentum equations. According to the dynamic model, the spiral motion in the underwater space is simulated for the gliding mode. Similarly the cycle motion on water surface and the depth-keeping motion underwater are simulated for the level-flight mode. These simulations are important to the performance analysis and parameter optimization for the Petrel-II underwater glider. The simulation results show a good agreement with field trials.

The Effects of Nuclear Weapons

Energy Technology Data Exchange (ETDEWEB)

Glasstone, Samuel

1957-06-01

This handbook prepared by the Armed Forces Special Weapons Project of the Department of Defense in coordination with other cognizant government agencies and published by the United States Atomic Energy Commission, is a comprehensive summary of current knowledge on the effects of nuclear weapons. The effects information contained herein is calculated for yields up to 20 megatons and the scaling laws for hypothetically extending the calculations beyond this limit are given. The figure of 20 megatons however is not be taken as an indication of capabilities or developments.

Asynchronous data-driven classification of weapon systems

International Nuclear Information System (INIS)

Jin, Xin; Mukherjee, Kushal; Gupta, Shalabh; Ray, Asok; Phoha, Shashi; Damarla, Thyagaraju

2009-01-01

This communication addresses real-time weapon classification by analysis of asynchronous acoustic data, collected from microphones on a sensor network. The weapon classification algorithm consists of two parts: (i) feature extraction from time-series data using symbolic dynamic filtering (SDF), and (ii) pattern classification based on the extracted features using the language measure (LM) and support vector machine (SVM). The proposed algorithm has been tested on field data, generated by firing of two types of rifles. The results of analysis demonstrate high accuracy and fast execution of the pattern classification algorithm with low memory requirements. Potential applications include simultaneous shooter localization and weapon classification with soldier-wearable networked sensors. (rapid communication)

Apparatus for Changing the Attack Angle of a Cavitator on a Supercavatating Underwater Research Model

Science.gov (United States)

2005-07-18

the Invention 14 The present invention generally relates to an apparatus 15 for changing the attack of a cavitator on a supercavitating 16 underwater...research model. 17 2. Description of the Prior Art 18 Supercavitating underwater vehicles and projectiles are 19 known in the art. One such... supercavitating underwater 20 projectile is described in Harkins et al., U.S. Patent No. 21 5,955,698. This projectile uses a supercavitating nose 22 section that

Secure Cooperation of Autonomous Mobile Sensors Using an Underwater Acoustic Network

Directory of Open Access Journals (Sweden)

Gianluca Dini

2012-02-01

Full Text Available Methodologies and algorithms are presented for the secure cooperation of a team of autonomous mobile underwater sensors, connected through an acoustic communication network, within surveillance and patrolling applications. In particular, the work proposes a cooperative algorithm in which the mobile underwater sensors (installed on Autonomous Underwater Vehicles—AUVs respond to simple local rules based on the available information to perform the mission and maintain the communication link with the network (behavioral approach. The algorithm is intrinsically robust: with loss of communication among the vehicles the coverage performance (i.e., the mission goal is degraded but not lost. The ensuing form of graceful degradation provides also a reactive measure against Denial of Service. The cooperative algorithm relies on the fact that the available information from the other sensors, though not necessarily complete, is trustworthy. To ensure trustworthiness, a security suite has been designed, specifically oriented to the underwater scenario, and in particular with the goal of reducing the communication overhead introduced by security in terms of number and size of messages. The paper gives implementation details on the integration between the security suite and the cooperative algorithm and provides statistics on the performance of the system as collected during the UAN project sea trial held in Trondheim, Norway, in May 2011.

Predictive Model for the Analysis of the Effects of Underwater Impulsive Sources on Marine Life

National Research Council Canada - National Science Library

Lazauski, Colin J

2007-01-01

A method is provided to predict the biological consequences to marine animals from exposure to multiple underwater impulsive sources by simulating underwater explosions over a defined period of time...

ON THE OFFENSE: USING CYBER WEAPONS TO INFLUENCE COGNITIVE BEHAVIOR

Directory of Open Access Journals (Sweden)

Mary Fendley

2012-12-01

Full Text Available There is an increasing recognition that cyber warfare is an important area of development for targeting and weaponeering, with far-reaching effects in national defense and economic security. The ability to conduct effective operations in cyberspace relies on a robust situational awareness of events occurring in both the physical and information domains, with an understanding of how they affect the cognitive domain of friendly, neutral, and adversary population sets. The dynamic nature of the battlefield complicates efforts to understand shifting adversary motivations and intentions. There are very few approaches, to date, that systematically evaluate the effects of the repertoire of cyber weapons on the cognitive, perceptual, and behavioral characteristics of the adversary. In this paper, we describe a software environment called Cognitive Cyber Weapon Selection Tool (CCWST that simulates a scenario involving cyber weaponry.This tool provides the capabilities to test weapons which may induce behavioral state changes in the adversaries. CCWST provides the required situational awareness to the Cyber Information Operations (IO planner to conduct intelligent weapon selection during weapon activation in order to induce the desired behavioral change in the perception of the adversary. Weapons designed to induce the cognitive state changes of deception, distraction, distrust and confusion were then tested empirically to evaluate the capabilities and expected cognitive state changes induced by these weapons. The results demonstrated that CCWST is a powerful environment within which to test and evaluate the impact of cyber weapons on influencing cognitive behavioral states during information processing.

Validation of multi-body modelling methodology for reconfigurable underwater robots

DEFF Research Database (Denmark)

Nielsen, M.C.; Eidsvik, O. A.; Blanke, Mogens

2016-01-01

This paper investigates the problem of employing reconfigurable robots in an underwater setting. The main results presented is the experimental validation of a modelling methodology for a system consisting of N dynamically connected robots with heterogeneous dynamics. Two distinct types...... of experiments are performed, a series of hydrostatic free-decay tests and a series of open-loop trajectory tests. The results are compared to a simulation based on the modelling methodology. The modelling methodology shows promising results for usage with systems composed of reconfigurable underwater modules...

Underwater laser beam welding of Alloy 690

International Nuclear Information System (INIS)

Hino, Takehisa; Tamura, Masataka; Kono, Wataru; Kawano, Shohei; Yoda, Masaki

2009-01-01

Stress Corrosion Clacking (SCC) has been reported at Alloy 600 welds between nozzles and safe-end in Pressurized Water Reactor (PWR) plant. Alloy 690, which has higher chromium content than Alloy 600, has been applied for cladding on Alloy 600 welds for repairing damaged SCC area. Toshiba has developed Underwater Laser Beam Welding technique. This method can be conducted without draining, so that the repairing period and the radiation exposure during the repair can be dramatically decreased. In some old PWRs, high-sulfur stainless steel is used as the materials for this section. It has a high susceptibility of weld cracks. Therefore, the optimum welding condition of Alloy 690 on the high-sulfur stainless steel was investigated with our Underwater Laser Beam Welding unit. Good cladding layer, without any crack, porosity or lack of fusion, could be obtained. (author)

A Comprehensive Study on the Internet of Underwater Things: Applications, Challenges, and Channel Models.

Science.gov (United States)

Kao, Chien-Chi; Lin, Yi-Shan; Wu, Geng-De; Huang, Chun-Ju

2017-06-22

The Internet of Underwater Things (IoUT) is a novel class of Internet of Things (IoT), and is defined as the network of smart interconnected underwater objects. IoUT is expected to enable various practical applications, such as environmental monitoring, underwater exploration, and disaster prevention. With these applications, IoUT is regarded as one of the potential technologies toward developing smart cities. To support the concept of IoUT, Underwater Wireless Sensor Networks (UWSNs) have emerged as a promising network system. UWSNs are different from the traditional Territorial Wireless Sensor Networks (TWSNs), and have several unique properties, such as long propagation delay, narrow bandwidth, and low reliability. These unique properties would be great challenges for IoUT. In this paper, we provide a comprehensive study of IoUT, and the main contributions of this paper are threefold: (1) we introduce and classify the practical underwater applications that can highlight the importance of IoUT; (2) we point out the differences between UWSNs and traditional TWSNs, and these differences are the main challenges for IoUT; and (3) we investigate and evaluate the channel models, which are the technical core for designing reliable communication protocols on IoUT.

Mechanically durable underwater superoleophobic surfaces based on hydrophilic bulk metals for oil/water separation

Science.gov (United States)

Yu, Huadong; Lian, Zhongxu; Xu, Jinkai; Wan, Yanling; Wang, Zuobin; Li, Yiquan; Yu, Zhanjiang; Weng, Zhankun

2018-04-01

Despite the success of previous methods for fabricating underwater superoleophobic surfaces, most of the surfaces based on soft materials are prone to collapse and deformation due to their mechanically fragile nature, and they fail to perform their designed functions after the surface materials are damaged in water. In this work, the nanosecond laser-induced oxide coatings on hydrophilic bulk metals are reported which overcomes the limitation and shows the robust underwater superoleophobicity to a mechanical challenge encountered by surfaces deployed in water environment. The results show that the surface materials have the advantage that the underwater superoleophobicity is still preserved after the surfaces are scratched by knife or sandpaper and even completely destroyed because of the hydrophilic property of damaged materials in water. It is important that the results provide a guide for the design of durable underwater superoleophobic surfaces, and the development of superoleophobic materials in many potential applications such as the oil-repellent and the oil/water separation. Additionally, the nanosecond laser technology is simple, cost-effective and suitable for the large-area and mass fabrication of mechanically durable underwater superoleophobic metal materials.

Tracking Controller Design for Diving Behavior of an Unmanned Underwater Vehicle

Directory of Open Access Journals (Sweden)

Yi-Hsiang Tseng

2013-01-01

Full Text Available The study has investigated the almost disturbance decoupling problem of nonlinear uncertain control systems via the fuzzy feedback linearization approach. The significant dedication of this paper is to organize a control algorithm such that the closed-loop system is active for given initial condition and bounded tracking trajectory with the input-to-state stability and almost disturbance decoupling performance. This study presents a feedback linearization controller for diving control of an unmanned underwater vehicle. Unmanned underwater vehicle proposes difficult control subject due to its nonlinear dynamics, uncertain models, and the existence of disturbances that are difficult to measure. In general, while investigating the diving dynamics of an unmanned underwater vehicle, the pitch angle is always assumed to be small. This assumption is a strong restricting constraint in many interesting practical applications and will be relaxed in this study.

An Environment-Friendly Multipath Routing Protocol for Underwater Acoustic Sensor Network

Directory of Open Access Journals (Sweden)

Yun Li

2017-01-01

Full Text Available Underwater Acoustic Sensor Network (UASN is a promising technique by facilitating a wide range of aquatic applications. However, routing scheme in UASN is a challenging task because of the characteristics of the nodes mobility, interruption of link, and interference caused by other underwater acoustic systems such as marine mammals. In order to achieve reliable data delivery in UASN, in this work, we present a disjoint multipath disruption-tolerant routing protocol for UASN (ENMR, which incorporates the Hue, Saturation, and Value color space (HSV model to establish routing paths to greedily forward data packets to sink nodes. ENMR applies the mechanism to maintain the network topology. Simulation results show that, compared with the classic underwater routing protocols named PVBF, ENMR can improve packet delivery ratio and reduce network latency while avoiding introducing additional energy consumption.

A study on practical use of underwater abrasive water jet cutting

Science.gov (United States)

Yamaguchi, Hitoshi; Demura, Kenji

1993-09-01

The practicality of underwater abrasive water jet cutting technology was studied in experiments. A study of abrasives in slurried form showed that optimum polymer concentration can be selected to suit underwater conditions. For the long-distance transport of slurry from the ocean surface to the ocean floor, a direct supply system by hose proved to be practical. This system takes advantage of the insolubility of the slurry in water due to a difference in specific gravity. For cutting thick steel plate at great ocean depths, a simulation with a pressurized container revealed the requirements for actual cutting. Confirmation of remote cutting operations will become the most important technology in field applications. Underwater sound vibration characteristics were found to change significantly in direct response to modifications in cutting conditions. This will be important basic data to develop an effective sensoring method.

Proposals for chemical weapons during the American Civil War.

Science.gov (United States)

Hasegawa, Guy R

2008-05-01

Proposals for chemical weapons that arose during the American Civil War are described. Most incendiary and all biological agents are excluded. The described proposals appeared primarily in periodicals or letters to government officials on both sides. The weapons were usually meant to temporarily disable enemy combatants, but some might have been lethal, and Civil War caregivers were ill-prepared to deal with the weapons' effects. Evidently, none of the proposed weapons were used. In only one instance was use against civilians mentioned. Among the agents most commonly proposed were cayenne pepper or other plant-based irritants such as black pepper, snuff, mustard, and veratria. Other suggested agents included chloroform, chlorine, hydrogen cyanide, arsenic compounds, sulfur, and acids. Proponents usually suggested that the chemicals be included in explosive artillery projectiles. Less commonly proposed vehicles of delivery included fire engines, kites, and manned balloons. Some of the proposed weapons have modern counterparts.

Measurement and Analysis of the Diffusible Hydrogen in Underwater Wet Welding Joint

Directory of Open Access Journals (Sweden)

Kong Xiangfeng

2016-01-01

Full Text Available The diffusible hydrogen in steel weldments is one of the main reasons that led to hydrogen assisted cracking. In this paper, the results of literatures survey and preliminary tests of the diffusible hydrogen in underwater wet welding joint were presented. A fluid-discharge method of for measuring the diffusible hydrogen in weldment was introduced in detail. Two kinds of underwater welding electrode diffusible hydrogen are 26.5 mL/100g and 35.5 mL/100g by fluid-discharge method, which are high levels. The diffusible hydrogen of underwater welding is higher than atmospheric welding, and the result is closely related to welding material. The best way to control the diffusible hydrogen is adjusting welding material and improving fluidity of slag.

Canadian--American relations and the nuclear weapons controversy, 1958--1963

International Nuclear Information System (INIS)

Ghent, J.M.

1976-01-01

This study attempts to explain the nuclear weapons controversy as it developed between 1958 and 1963. The nuclear controversy centered around Canada's acceptance of a nuclear role, within the American alliance system, for the Canadian armed forces. In the period 1958-1959, when the critical weapons decisions were being taken, Canadian political authorities lost control of the policy-making process, permitting the Canadian and American military bureacracies to initiate nuclear plans suited to their common needs and objectives. Prime Minister Diefenbaker's reluctance to arm the systems acquired by transborder bureaucratic coalition is also re-examined. Previous analysts have regarded the government's hesitations over nuclear weapons as the product of Diefenbaker's personal antagonism towards President Kennedy or as a futile attempt to reverse the process of continental integration. The opening of the Kennedy papers reveals the degree to which Diefenbaker was committed to close Canadian-American cooperation and the effort he made to overcome the president's hostility towards him. This study emphasizes the importance of Diefenbaker's sensitivity to public, parliamentary, and cabinet opposition to nuclear arms. The secret U.S. demand for nuclear bases in Labrador and Newfoundland is revealed. Thus the question of nuclear storage in Canada for Canadian forces was complicated by U.S. insistence that Canada simultaneously provide nuclear storage for the strategic forces of the U.S. Finally, the extent of American responsibility for Diefenbaker's demise is re-assessed, and the conclusion is reached that the U.S., through Canadian-American military interaction and the initiative of the ambassador in Ottawa, did in fact help to bring down the government of Canada

Nuclear weapons headed for the trash

International Nuclear Information System (INIS)

Arkin, W.M.; Durrant, D.; Kristensen, H.

1991-01-01

Whether he intended it or not, Bush has taken steps that mean the beginning of the end for nuclear weapons. His proposals significantly reduce the numbers of nuclear weapons and the burdens associated with deploying and controlling them. And although he retains many of the options for continuing and regenerating the nuclear arsenal, he has exposed the fact that there are no longer any grand justifications or doctrinal needs for nuclear weapons - and that the nuclear machine is choking on its economic, political, environmental, and human contradictions. The initiatives fundamentally altered the nuclear stance of both nations. Yet, as momentous as the changes were, they were set in motion in an almost businesslike manner. Neither leader truly framed the moves as an end to the nuclear age. But they didn't need to. The steps they have taken practically guarantee it

Underwater navigation using diffusion-based trajectory observers

DEFF Research Database (Denmark)

Jouffroy, Jerome; Opderbecke, Jan

2007-01-01

This paper addresses the issue of estimating underwater vehicle trajectories using gyro-Doppler (body-fixed velocities) and acoustic positioning signals (earth-fixed positions). The approach consists of diffusion-based observers processing a whole trajectory segment at a time, allowing the consid...

Responsibilities of the nuclear-weapon states

International Nuclear Information System (INIS)

Wang Jun

1994-01-01

The responsibilities of Nuclear Weapon States are presented by a straightforward analysis together with the ways in which they could fulfill them. The complete undertaking of all the commitments by the Nuclear Weapon States may take a long time. However they do not have a single excuse to neglect such a historic opportunity to do their best to provide a genuinely secure world environment for the international community, of which they too are members

Chemical and biological weapons in the 'new wars'.

Science.gov (United States)

Ilchmann, Kai; Revill, James

2014-09-01

The strategic use of disease and poison in warfare has been subject to a longstanding and cross-cultural taboo that condemns the hostile exploitation of poisons and disease as the act of a pariah. In short, biological and chemical weapons are simply not fair game. The normative opprobrium is, however, not fixed, but context dependent and, as a social phenomenon, remains subject to erosion by social (or more specifically, antisocial) actors. The cross cultural understanding that fighting with poisons and disease is reprehensible, that they are taboo, is codified through a web of interconnected measures, principal amongst these are the 1925 Geneva Protocol; the Biological Weapons Convention; and the Chemical Weapons Convention. Whilst these treaties have weathered the storm of international events reasonably well, their continued health is premised on their being 'tended to' in the face of contextual changes, particularly facing changes in science and technology, as well as the changed nature and character of conflict. This article looks at the potential for normative erosion of the norm against chemical and biological weapons in the face of these contextual changes and the creeping legitimization of chemical and biological weapons.

Application of a Dynamic Programming Algorithm for Weapon Target Assignment

Science.gov (United States)

2016-02-01

evaluation and weapon assignment in maritime combat scenarios. Lloyd also acts as a liaison for the Weapons and Combat Systems Division with the ANZAC...positively identified a number of targets as threats, whether they are an enemy ship (i.e., specifically, its weapon launcher systems) or a directed

Development of a highly maneuverable unmanned underwater vehicle on the basis of quad-copter dynamics

Science.gov (United States)

Amin, Osman Md; Karim, Md. Arshadul; Saad, Abdullah His

2017-12-01

At present, research on unmanned underwater vehicle (UUV) has become a significant & familiar topic for researchers from various engineering fields. UUV is of mainly two types - AUV (Autonomous Underwater vehicle) & ROV (Remotely Operated Vehicle). There exist a significant number of published research papers on UUV, where very few researchers emphasize on the ease of maneuvering and control of UUV. Maneuvering is important for underwater vehicle in avoiding obstacles, installing underwater piping system, searching undersea resources, underwater mine disposal operations, oceanographic surveys etc. A team from Dept. of Naval Architecture & Marine Engineering of MIST has taken a project to design a highly maneuverable unmanned underwater vehicle on the basis of quad-copter dynamics. The main objective of the research is to develop a control system for UUV which would be able to maneuver the vehicle in six DOF (Degrees of Freedom) with great ease. For this purpose we are not only focusing on controllability but also designing an efficient hull with minimal drag force & optimized propeller using CFD technique. Motors were selected on the basis of the simulated thrust generated by propellers in ANSYS Fluent software module. Settings for control parameters to carry out different types of maneuvering such as hovering, spiral, one point rotation about its centroid, gliding, rolling, drifting and zigzag motions were explained in short at the end.

Insights into the Underwater Diving, Feeding, and Calling Behavior of Blue Whales from a Suction-Cup-Attached Video-Imaging Tag (CRITTERCAM)

Science.gov (United States)

2008-01-01

San Diego Diane Gendron Centro Interdisciplinario de Ciencias Marinas Kelly Robertson Southwest Fisheries Science Center- NMFS/NOAA P A P E R Insights...archival tags have begun to provide more details about underwater behaviors, in- cluding feeding and social behaviors (Goldbogen et al., 2006; Oleson...Volume 41, Number 4 TABLE 2 Summary of deployments of CRITTERCAMS used in this article . TABLE 3 Summary of resightings based on photo-ID of whales in this

Single High Fidelity Geometric Data Sets for LCM - Model Requirements

Science.gov (United States)

2006-11-01

designed specifically to withstand severe underwater explosion (UNDEX) loading caused by the detonation of weapons such as bombs, missiles, mines and... Explosions ( BLEVEs ): The energy from a BLEVE is from a sudden change of phase of stored material. Tanks of liquids immersed in pool fires BLEVE when the...2.10.3 Summary of Data Requirements ....................................................... 46 2.11 Underwater Explosion

Legality of the threat or use of nuclear weapons

International Nuclear Information System (INIS)

Chang Yenchiang

2009-01-01

This paper examines international treaties in relation to the threat or use of nuclear weapons including the 1968 Nuclear Non-Proliferation Treaty and the 1996 Comprehensive Test Ban Treaty. It can be concluded that the effect of the aforesaid international treaties is still in doubt without explicit enforcement mechanisms and penalty for non-compliance. This paper also reviews the International Court of Justice's advisory opinion on the legality of the threat or use of nuclear weapons and comments that a clear explanation on the legality of use of nuclear weapons in 'extreme circumstances of self-defence' is required. Examples from current state practice in relation to nuclear non-proliferation efforts are also provided, with special attention to China, North Korea and Iran. This paper suggests that China as a leader of developing countries should extend its efforts on nuclear non-proliferation and conduct communication between North Korea and Iran and other nuclear weapons states to reduce or prohibit nuclear weapons.

3D MODELING FOR UNDERWATER ARCHAEOLOGICAL DOCUMENTATION: METRIC VERIFICATIONS

Directory of Open Access Journals (Sweden)

S. D’Amelio

2015-04-01

Full Text Available The survey in underwater environment has always presented considerable difficulties both operative and technical and this has sometimes made it difficult to use the techniques of survey commonly used for the documentation of Cultural Heritage in dry environment. The work of study concerns the evaluation in terms of capability and accuracy of the Autodesk123DCatch software for the reconstruction of a three-dimensional model of an object in underwater context. The subjects of the study are models generated from sets of photographs and sets of frames extracted from video sequence. The study is based on comparative method, using a reference model, obtained with laser scanner technique.

Pressure vessel made by free forming using underwater explosion

Directory of Open Access Journals (Sweden)

H Iyama

2016-03-01

Full Text Available Explosive forming is one particular forming technique, in which, mostcommonly, water is used as the pressure transmission medium. In recentyears, we have done the development of the method which obtains anecessary form of the metal by the control of underwater shock wave actson the metal plate, without a metal die. On the other hand, the pressurevessel is required in various fields, but we think that the free forming usingthe underwater shock wave is advantageous in the production of pressurevessel of a simple spherical, ellipse, parabola shape. In this paper, we willintroduce an experiment and several numerical simulations that we carriedout for this technical development.

Conflict Without Casualties: Non-Lethal Weapons in Irregular Warfare

Science.gov (United States)

2007-09-01

the body,” and the Geneva Protocol of 1925, bans the use of chemical and biological weapons .11 On 8 April 1975, President Ford issued Executive...E Funding – PE 63851M) (accessed 15 December 2006). The American Journal of Bioethics . “Medical Ethics and Non-Lethal Weapons .” Bioethics.net...CASUALTIES: NON-LETHAL WEAPONS IN IRREGULAR WARFARE by Richard L. Scott September 2007 Thesis Advisor: Robert McNab Second Reader

Localization of an Underwater Control Network Based on Quasi-Stable Adjustment

Science.gov (United States)

Chen, Xinhua; Zhang, Hongmei; Feng, Jie

2018-01-01

There exists a common problem in the localization of underwater control networks that the precision of the absolute coordinates of known points obtained by marine absolute measurement is poor, and it seriously affects the precision of the whole network in traditional constraint adjustment. Therefore, considering that the precision of underwater baselines is good, we use it to carry out quasi-stable adjustment to amend known points before constraint adjustment so that the points fit the network shape better. In addition, we add unconstrained adjustment for quality control of underwater baselines, the observations of quasi-stable adjustment and constrained adjustment, to eliminate the unqualified baselines and improve the results’ accuracy of the two adjustments. Finally, the modified method is applied to a practical LBL (Long Baseline) experiment and obtains a mean point location precision of 0.08 m, which improves by 38% compared with the traditional method. PMID:29570627

On the Accuracy Potential in Underwater/Multimedia Photogrammetry.

Science.gov (United States)

Maas, Hans-Gerd

2015-07-24

Underwater applications of photogrammetric measurement techniques usually need to deal with multimedia photogrammetry aspects, which are characterized by the necessity of handling optical rays that are refracted at interfaces between optical media with different refractive indices according to Snell's Law. This so-called multimedia geometry has to be incorporated into geometric models in order to achieve correct measurement results. The paper shows a flexible yet strict geometric model for the handling of refraction effects on the optical path, which can be implemented as a module into photogrammetric standard tools such as spatial resection, spatial intersection, bundle adjustment or epipolar line computation. The module is especially well suited for applications, where an object in water is observed by cameras in air through one or more planar glass interfaces, as it allows for some simplifications here. In the second part of the paper, several aspects, which are relevant for an assessment of the accuracy potential in underwater/multimedia photogrammetry, are discussed. These aspects include network geometry and interface planarity issues as well as effects caused by refractive index variations and dispersion and diffusion under water. All these factors contribute to a rather significant degradation of the geometric accuracy potential in underwater/multimedia photogrammetry. In practical experiments, a degradation of the quality of results by a factor two could be determined under relatively favorable conditions.

Prions: the danger of biochemical weapons

Directory of Open Access Journals (Sweden)

Eric Almeida Xavier

2014-09-01

Full Text Available The knowledge of biotechnology increases the risk of using biochemical weapons for mass destruction. Prions are unprecedented infectious pathogens that cause a group of fatal neurodegenerative diseases by a novel mechanism. They are transmissible particles that are devoid of nucleic acid. Due to their singular characteristics, Prions emerge as potential danger since they can be used in the development of such weapons. Prions cause fatal infectious diseases, and to date there is no therapeutic or prophylactic approach against these diseases. Furthermore, Prions are resistant to food-preparation treatments such as high heat and can find their way from the digestive system into the nervous system; recombinant Prions are infectious either bound to soil particles or in aerosols. Therefore, lethal Prions can be developed by malicious researchers who could use it to attack political enemies since such weapons cause diseases that could be above suspicion.

46 CFR 115.650 - Alternative Hull Examination (AHE) Program options: Divers or underwater ROV.

Science.gov (United States)

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Alternative Hull Examination (AHE) Program options... MORE THAN 49 PASSENGERS INSPECTION AND CERTIFICATION Hull and Tailshaft Examinations § 115.650 Alternative Hull Examination (AHE) Program options: Divers or underwater ROV. To complete your underwater...

Hamburgian weapon delivery technology: a quantitative comparative approach

DEFF Research Database (Denmark)

Riede, Felix

2010-01-01

cran). Numerous studies have addressed the question of whether these points tipped arrows fired from bows, darts launched with the help of spear-throwers, or some other projectile delivery weapon. This paper approaches the question of Hamburgian weapon delivery technology from a quantitative...

Deep Attack Weapons Mix Study (DAWMS) Case Study

National Research Council Canada - National Science Library

Bexfield, James

2001-01-01

.... This report describes the process used to conduct the Deep Attack Weapons Mix Study (DAWMS) in 1995-1997. This case study focuses on the weapons being procured by the Services and whether a joint viewpoint would result in a more effective mix...

Experimental study on scale removal from special-shaped conduits through underwater electrical discharge

International Nuclear Information System (INIS)

Cao, Y; Wang, Z Q; Li, G F; Wu, Y; Zhou, J J

2013-01-01

Underwater electrical discharge technology is an innovative technique that can be used to enhance the stress intensity of water and improve the load addition. The technique enlarges the section area and compresses the surrounding water using a high-powered shock wave, which is induced by an underwater electrical discharge. This paper investigates the effectiveness of scale removal for special-shaped conduits employing underwater electrical discharge. Experimental results show that the pressure wave generated by underwater electrical discharge is capable of eliminating scale in special-shaped conduits. The data indicates that when the capacitance of the parallel-pulsed capacitors was 4 μF, the high pulsed power voltage was 33 kV and the primary discharge gap was 48 mm, the result of scale removal was remarkable. In laboratory tests, the scale of special equipment was removed to a great extent by this method. Because of its effectiveness and low cost, this method improves the practice and extends the lifetime of such equipment, and thus has potential application and economic value.

Underwater explosive compaction-sintering of tungsten-copper coating on a copper surface

Science.gov (United States)

Chen, Xiang; Li, Xiaojie; Yan, Honghao; Wang, Xiaohong; Chen, Saiwei

2018-01-01

This study investigated underwater explosive compaction-sintering for coating a high-density tungsten-copper composite on a copper surface. First, 50% W-50% Cu tungsten-copper composite powder was prepared by mechanical alloying. The composite powder was pre-compacted and sintered by hydrogen. Underwater explosive compaction was carried out. Finally, a high-density tungsten-copper coating was obtained by diffusion sintering of the specimen after explosive compaction. A simulation of the underwater explosive compaction process showed that the peak value of the pressure in the coating was between 3.0 and 4.8 GPa. The hardness values of the tungsten-copper layer and the copper substrate were in the range of 87-133 and 49 HV, respectively. The bonding strength between the coating and the substrate was approximately 100-105 MPa.

A Comprehensive Study on the Internet of Underwater Things: Applications, Challenges, and Channel Models

Directory of Open Access Journals (Sweden)

Chien-Chi Kao

2017-06-01

Full Text Available The Internet of Underwater Things (IoUT is a novel class of Internet of Things (IoT, and is defined as the network of smart interconnected underwater objects. IoUT is expected to enable various practical applications, such as environmental monitoring, underwater exploration, and disaster prevention. With these applications, IoUT is regarded as one of the potential technologies toward developing smart cities. To support the concept of IoUT, Underwater Wireless Sensor Networks (UWSNs have emerged as a promising network system. UWSNs are different from the traditional Territorial Wireless Sensor Networks (TWSNs, and have several unique properties, such as long propagation delay, narrow bandwidth, and low reliability. These unique properties would be great challenges for IoUT. In this paper, we provide a comprehensive study of IoUT, and the main contributions of this paper are threefold: (1 we introduce and classify the practical underwater applications that can highlight the importance of IoUT; (2 we point out the differences between UWSNs and traditional TWSNs, and these differences are the main challenges for IoUT; and (3 we investigate and evaluate the channel models, which are the technical core for designing reliable communication protocols on IoUT.

Network lifetime-aware data collection in Underwater Sensor ...

Indian Academy of Sciences (India)

Jalaja Janardanan Kartha

2017-09-07

Sep 7, 2017 ... existing models to assess their effectiveness and to investigate the trade-offs. Results show ... coverage drops below a predefined threshold and (vi) connectivity is .... Cost Clustering Protocol (MCCP), Distributed Underwater.

Application of inertial confinement fusion to weapon technology

International Nuclear Information System (INIS)

Toepfer, A.J.; Posey, L.D.

1978-12-01

This report reviews aspects of the military applications of the inertial confinement fusion (ICF) program at Sandia Laboratories. These applications exist in the areas of: (1) weapon physics research, and (2) weapon effects simulation. In the area of weapon physics research, ICF source technology can be used to study: (1) equations-of-state at high energy densities, (2) implosion dynamics, and (3) laboratory simulation of exoatmospheric burst phenomena. In the area of weapon effects simulation, ICF technology and facilities have direct near, intermediate, and far term applications. In the near term, short pulse x-ray simulation capabilities exist for electronic component effects testing. In the intermediate term, capabilities can be developed for high energy neutron exposures and bremsstrahlung x-ray exposures of components. In the far term, system level exposures of full reentry vehicles will be possible if sufficiently high pellet gains are achieved

The Control Packet Collision Avoidance Algorithm for the Underwater Multichannel MAC Protocols via Time-Frequency Masking

Directory of Open Access Journals (Sweden)

Yang Yu

2016-01-01

Full Text Available Establishing high-speed and reliable underwater acoustic networks among multiunmanned underwater vehicles (UUVs is basic to realize cooperative and intelligent control among different UUVs. Nevertheless, different from terrestrial network, the propagation speed of the underwater acoustic network is 1500 m/s, which makes the design of the underwater acoustic network MAC protocols a big challenge. In accordance with multichannel MAC protocols, data packets and control packets are transferred through different channels, which lowers the adverse effect of acoustic network and gradually becomes the popular issues of underwater acoustic networks MAC protocol research. In this paper, we proposed a control packet collision avoidance algorithm utilizing time-frequency masking to deal with the control packets collision in the control channel. This algorithm is based on the scarcity of the noncoherent underwater acoustic communication signals, which regards collision avoiding as separation of the mixtures of communication signals from different nodes. We first measure the W-Disjoint Orthogonality of the MFSK signals and the simulation result demonstrates that there exists time-frequency mask which can separate the source signals from the mixture of the communication signals. Then we present a pairwise hydrophones separation system based on deep networks and the location information of the nodes. Consequently, the time-frequency mask can be estimated.

Acquisition and tracking for underwater optical communications

Science.gov (United States)

Williams, Andrew J.; Laycock, Leslie L.; Griffith, Michael S.; McCarthy, Andrew G.; Rowe, Duncan P.

2017-10-01

There is a growing requirement to transfer large volumes of data between underwater platforms. As seawater is transmissive in the visible band, underwater optical communications is an active area of interest since it offers the potential for power efficient, covert and high bandwidth datalinks at short to medium ranges. Short range systems have been successfully demonstrated using sources with low directionality. To realise higher data rates and/or longer ranges, the use of more efficient directional beams is required; by necessity, these must be sufficiently aligned to achieve the required link margin. For mobile platforms, the acquisition and tracking of each node is therefore critical in order to establish and maintain an optical datalink. This paper describes work undertaken to demonstrate acquisition and tracking in a 3D underwater environment. A range of optical sources, beam steering technologies, and tracking sensors have been assessed for suitability. A novel scanning strategy exploiting variable beam divergence was developed to provide robust acquisition whilst minimising acquisition time. A prototype system was assembled and demonstrated in a large water tank. This utilised custom quadrant detectors based on Silicon PhotoMultiplier (SiPM) arrays for fine tracking, and a Wide Field of View (WFoV) sCMOS camera for link acquisition. Fluidic lenses provided dynamic control of beam divergence, and AC modulation/filtering enabled background rejection. The system successfully demonstrated robust optical acquisition and tracking between two nodes with only nanowatt received optical powers. The acquisition time was shown to be dependent on the initial conditions and the transmitted optical power.

Cascading Multi-Hop Reservation and Transmission in Underwater Acoustic Sensor Networks

Directory of Open Access Journals (Sweden)

Jae-Won Lee

2014-10-01

Full Text Available The long propagation delay in an underwater acoustic channel makes designing an underwater media access control (MAC protocol more challenging. In particular, handshaking-based MAC protocols widely used in terrestrial radio channels have been known to be inappropriate in underwater acoustic channels, because of the inordinately large latency involved in exchanging control packets. Furthermore, in the case of multi-hop relaying in a hop-by-hop handshaking manner, the end-to-end delay significantly increases. In this paper, we propose a new MAC protocol named cascading multi-hop reservation and transmission (CMRT. In CMRT, intermediate nodes between a source and a destination may start handshaking in advance for the next-hop relaying before handshaking for the previous node is completed. By this concurrent relaying, control packet exchange and data delivery cascade down to the destination. In addition, to improve channel utilization, CMRT adopts a packet-train method where multiple data packets are sent together by handshaking once. Thus, CMRT reduces the time taken for control packet exchange and accordingly increases the throughput. The performance of CMRT is evaluated and compared with that of two conventional MAC protocols (multiple-access collision avoidance for underwater (MACA-U and MACA-U with packet trains (MACA-UPT. The results show that CMRT outperforms other MAC protocols in terms of both throughput and end-to-end delay.

Measurement and Modeling of Narrowband Channels for Ultrasonic Underwater Communications

Directory of Open Access Journals (Sweden)

Francisco J. Cañete

2016-02-01

Full Text Available Underwater acoustic sensor networks are a promising technology that allow real-time data collection in seas and oceans for a wide variety of applications. Smaller size and weight sensors can be achieved with working frequencies shifted from audio to the ultrasonic band. At these frequencies, the fading phenomena has a significant presence in the channel behavior, and the design of a reliable communication link between the network sensors will require a precise characterization of it. Fading in underwater channels has been previously measured and modeled in the audio band. However, there have been few attempts to study it at ultrasonic frequencies. In this paper, a campaign of measurements of ultrasonic underwater acoustic channels in Mediterranean shallow waters conducted by the authors is presented. These measurements are used to determine the parameters of the so-called κ-μ shadowed distribution, a fading model with a direct connection to the underlying physical mechanisms. The model is then used to evaluate the capacity of the measured channels with a closed-form expression.

Multiuser chirp modulation for underwater acoustic channel based on VTRM

Directory of Open Access Journals (Sweden)

Fei Yuan

2017-05-01

Full Text Available In this paper, an ascheme is proposed for multiuser underwater acoustic communication by using the multi-chirp rate signals. It differs from the well known TDMA (Time Division Multiple Access, FDMA (Frequency Division Multiple Access or CDMA (Code Division Multiple Access, by assigning each users with different chirp-rate carriers instead of the time, frequency or PN code. Multi-chirp rate signals can be separated from each other by FrFT (Fractional Fourier Transform, which can be regarded as the chirp-based decomposing, and superior to the match filter in the underwater acoustic channel. VTRM (Virtual Time Reverse Mirror is applied into the system to alleviate the ISI caused by the multipatch and make the equalization more simple. Results of computer simulations and pool experiments prove that the proposed multiuser underwater acoustic communication based on the multi-chirp rate exhibit well performance. Outfield experments carrie out in Xiamen Port show that using about 10 kHz bandwidth, four users could communicate at the same time with 425 bps with low BER and can match the UAC application.

The tale of the shrinking weapon: seasonal changes in nutrition affect weapon size and sexual dimorphism, but not contemporary evolution.

Science.gov (United States)

Miller, C W; McDonald, G C; Moore, A J

2016-11-01

Sexually selected traits are often highly variable in size within populations due to their close link with the physical condition of individuals. Nutrition has a large impact on physical condition, and thus, any seasonal changes in nutritional quality are predicted to alter the average size of sexually selected traits as well as the degree of sexual dimorphism in populations. However, although traits affected by mate choice are well studied, we have a surprising lack of knowledge of how natural variation in nutrition affects the expression of sexually selected weapons and sexual dimorphism. Further, few studies explicitly test for differences in the heritability and mean-scaled evolvability of sexually selected traits across conditions. We studied Narnia femorata (Hemiptera: Coreidae), an insect where males use their hind legs as weapons and the femurs are enlarged, to understand the extent to which weapon expression, sexual dimorphism and evolvability change across the actual range of nutrition available in the wild. We found that insects raised on a poor diet (cactus without fruit) are nearly monomorphic, whereas those raised on a high-quality diet (cactus with ripe fruit) are distinctly sexually dimorphic via the expression of large hind leg weapons in males. Contrary to our expectations, we found little evidence of a potential for evolutionary change for any trait measured. Thus, although we show weapons are highly condition dependent, and changes in weapon expression and dimorphism could alter evolutionary dynamics, our populations are unlikely to experience further evolutionary changes under current conditions. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Biological and Chemical Weapons: Criminal Sanctions and Federal Regulations

National Research Council Canada - National Science Library

Garcia, Michael J

2004-01-01

The Biological Weapons Convention and the Chemical Weapons Convention, both of which have been signed and ratified by the United States, obligate signatory parties to enact legislation or otherwise...

Non-Lethal Chemical Weapons

National Research Council Canada - National Science Library

Weilacher, Lester A

2003-01-01

Little more than a month after terrorists took control of four passenger aircraft in the United States and unleashed the horror of 9/11, 50 Chechen terrorists armed with automatic weapons and carrying...

Cooperative Security: A New Paradigm For A World Without Nuclear Weapons?

Directory of Open Access Journals (Sweden)

Marc Finaud

2013-11-01

Full Text Available If there is a loose consensus on aiming at a world free of nuclear weapons in the future, there are clear oppositions as to the timeframe as well as the means for achieving this goal. The approach to nuclear disarmament followed to date has only yielded limited success because it has been conceived in isolation from global and regional security environments and threat perceptions. A new paradigm should thus be sought in order to reconcile nuclear powers’ security doctrines with global aspirations for a safer world, and ensure that nuclear powers derive their security less from others’ insecurity but from mutually beneficial cooperative security. This should not become a pretext for preserving nuclear weapons for ever. It will on the contrary require parallel tracks addressing the initial motivations for acquiring nuclear weapons and other weapons of mass destruction (WMD, in particular in the context of regional conflicts, as well as dealing with the current issues necessarily related to nuclear disarmament (missile defence, weaponization of space, conventional imbalances and future weapon systems. Ultimately, in a globalised nuclear-weapon free world, state security will not require nuclear weapons because it will be inserted into a broader network encompass­ing all aspects of security addressed in cooperative and multilateral approaches.

Underwater noise generated by offshore pile driving

NARCIS (Netherlands)

Tsouvalas, A.

2015-01-01

Anthropogenic noise emission in the marine environment has always been an environmental issue of serious concern. In particular, the noise generated during the installation of foundation piles is considered to be one of the most significant sources of underwater noise pollution. This is mainly

MOSES, development of an Underwater Warfare Testbed

NARCIS (Netherlands)

Lentze, S.G.

2001-01-01

The TNO underwater warfare (UWW) research programme results in a large number of models used in operational research projects. To enhance the accessibility and re-use of these models for new projects, TNO-FEL has developed the modelling environment ‘MOSES - Maritime Operations Simulation and

Defense Acquisitions: Assessments of Selected Weapon Programs

Science.gov (United States)

2017-03-01

Figure 17: Examples of Knowledge Scorecards 61 Page vi GAO-17-333SP Assessments of Selected Weapon Programs...programs. Page 61 GAO-17-333SP Assessments of Selected Weapon Programs Figure 17: Examples of Knowledge Scorecards Pursuant to a...had direct access to the USD AT&L and other senior acquisition officials, and some approval authorities were delegated to lower levels. For example

77 FR 38236 - Special Local Regulation, Underwater Music Festival, Carr Inlet, Cutts Island, WA

Science.gov (United States)

2012-06-27

...-AA08 Special Local Regulation, Underwater Music Festival, Carr Inlet, Cutts Island, WA AGENCY: Coast... ensure the safety of the maritime public during the Underwater Music Festival and would do so by... Music Festival is an event which includes musical performances from a barge. Spectators approach the...

Radiation, chemical and biological protection. Mass destruction weapons

International Nuclear Information System (INIS)

Janasek, D.; Svetlik, J.

2005-01-01

In this text-book mass destruction weapons and radiation, chemical and biological protection are reviewed. The text-book contains the following chapter: (1) Mass destruction weapons; (2) Matter and material; (3) Radioactive materials; (4) Toxic materials; (5) Biological resources; (6) Nuclear energetic equipment; Appendices; References.

Human Injury Criteria for Underwater Blasts

Science.gov (United States)

2014-09-08

further underscored the need for this new guideline based on injury data. Conference Name: Personal Armour Systems Symposium Conference Date...29.  Cole, R., Underwater Explosion. (Dover Publications, Inc ., New York, N.Y., 1948) 30.  Nakahara, M., Nagayama, K, Mori, Y, Japanese Journal...Abstract of the Undersea and Hyperbaric Medical Society, Inc . Annual Scientific Meeting, (1976).

Can abolition of nuclear weapons be adequately verified?

International Nuclear Information System (INIS)

Rotblat, J.

1993-01-01

Speaking on the problems of preventing proliferations of nuclear weapons and nuclear disarmament the author suggests the following measures to reach these goals: signing a treaty that binds all the nuclear weapon states to the no-first-use principle as a basic policy; the United Nations should put the elimination of nuclear weapons on its agenda; having the treaty safeguarded two-pronged verification regime, one would be technological verification, the second one - so called societal verification which means that not just a group of experts but everybody would be asked to take part in ensuring that the treaty would not be violated

A Framework for Evaluating Advanced Search Concepts for Multiple Autonomous Underwater Vehicle (AUV) Mine Countermeasures (MCM)

National Research Council Canada - National Science Library

Gooding, Trent

2001-01-01

.... In recent years, autonomous underwater vehicles (AUV) have emerged as a viable technology for conducting underwater search, survey, and clearance operations in support of the mine countermeasures (MCM) mission...

The use of neutron scattering in nuclear weapons research

International Nuclear Information System (INIS)

Juzaitis, R.J.

1995-01-01

We had a weapons science breakout session last week. Although it would have been better to hold it closer in time to this workshop, I think that it was very valuable. it may have been less of a 'short-sleeve' workshop environment than we would have liked, but as the first time two communities-the weapons community and the neutron scattering community- got together, it was a wonderful opportunity to transfer information during the 24 presentations that were made. This report contains discussions on the fundamental analysis of documentation of the enduring stockpile; LANSCE's contribution to weapons; spallation is critical to understanding; weapons safety assessments; applied nuclear physics requires cross section information; fission models need refinement; and establishing teams on collaborative projects

Electrostatic images for underwater anisotropic conductive half spaces

International Nuclear Information System (INIS)

Flykt, M.; Lindell, I.; Eloranta, E.

1998-01-01

A static image principle makes it possible to derive analytical solutions to some basic geometries for DC fields. The underwater environment is especially difficult both from the theoretical and practical point of view. However, there are increasing demands that also the underwater geological formations should be studied in detail. The traditional image of a point source lies at the mirror point of the original. When anisotropic media is involved, however, the image location can change and the image source may be a continues, sector-like distribution. In this paper some theoretical considerations are carried out in the case where the lower half space can have a very general anisotropy in terms of electrical conductivity, while the upper half space is assumed isotropic. The reflection potential field is calculated for different values of electrical conductivity. (orig.)

A nuclear-weapon-free Middle East

International Nuclear Information System (INIS)

Jortner, Joshua

1986-01-01

The paper examines the issue of nuclear-weapon States involvement in regional conflicts, and whether such a conflict in the Middle East could trigger a nuclear war between the Super-Powers. Comments on the Middle Eastern situation are given, along with a discussion of the Non-Proliferation Treaty (NPT) and the Middle East, Israel and the NPT, and the nuclear potential in Arab countries. The proposal, by Israel, of a nuclear weapon-free zone in the Middle East is outlined. (UK)

Amarillo National Resource Center for plutonium. Work plan progress report, November 1, 1995--January 31, 1996

Energy Technology Data Exchange (ETDEWEB)

Cluff, D. [Texas Tech Univ., Lubbock, TX (United States)

1996-04-01

The Center operates under a cooperative agreement between DOE and the State of Texas and is directed and administered by an education consortium. Its programs include developing peaceful uses for the materials removed from dismantled weapons, studying effects of nuclear materials on environment and public health, remedying contaminated soils and water, studying storage, disposition, and transport of Pu, HE, and other hazardous materials removed from weapons, providing research and counsel to US in carrying out weapons reductions in cooperation with Russia, and conducting a variety of education and training programs.

Abramovo Counterterrorism Training Center

International Nuclear Information System (INIS)

Hayes, Christopher M.; Ross, Larry; Kaldenbach, Karen Yvonne; Estigneev, Yuri; Murievav, Andrey

2011-01-01

The U.S. government has been assisting the Russian Federation (RF) Ministry of Defense (MOD) for many years with nuclear weapons transportation security (NWTS) through the provision of specialized guard escort railcars and cargo railcars with integrated physical security and communication systems, armored transport vehicles, and armored escort vehicles. As a natural continuation of the NWTS program, a partnership has been formed to construct a training center that will provide counterterrorism training to personnel in all branches of the RF MOD. The Abramovo Counterterrorism Training Center (ACTC) is a multinational, multiagency project with funding from Canada, RF and the U.S. Departments of Defense and Energy. ACTC will be a facility where MOD personnel can conduct basic through advanced training in various security measures to protect Category IA material against the threat of terrorist attack. The training will enhance defense-in-depth principles by integrating MOD guard force personnel into the overall physical protection systems and improving their overall response time and neutralization capabilities. The ACTC project includes infrastructure improvements, renovation of existing buildings, construction of new buildings, construction of new training facilities, and provision of training and other equipment. Classroom training will be conducted in a renovated training building. Basic and intermediate training will be conducted on three different security training areas where various obstacles and static training devices will be constructed. The central element of ACTC, where advanced training will be held, is the 'autodrome,' a 3 km road along which various terrorist events can be staged to challenge MOD personnel in realistic and dynamic nuclear weapons transportation scenarios. This paper will address the ACTC project elements and the vision for training development and integrating this training into actual nuclear weapons transportation operations.

Efficient Modelling Methodology for Reconfigurable Underwater Robots

DEFF Research Database (Denmark)

Nielsen, Mikkel Cornelius; Blanke, Mogens; Schjølberg, Ingrid

2016-01-01

This paper considers the challenge of applying reconfigurable robots in an underwater environment. The main result presented is the development of a model for a system comprised of N, possibly heterogeneous, robots dynamically connected to each other and moving with 6 Degrees of Freedom (DOF). Th...

Impacts of underwater noise on marine vertebrates

NARCIS (Netherlands)

Liebschner, Alexander; Seibel, Henrike; Teilmann, Jonas; Wittekind, Dietrich; Parmentier, Eric; Dähne, Michael; Dietz, Rune; Driver, Jörg; Elk, van Cornelis; Everaarts, Eligius; Findeisen, Henning; Kristensen, Jacob; Lehnert, Kristina; Lucke, Klaus; Merck, Thomas; Müller, Sabine; Pawliczka, Iwona; Ronnenberg, Katrin; Rosenberger, Tanja; Ruser, Andreas; Tougaard, Jakob; Schuster, Max; Sundermeyer, Janne; Sveegaard, Signe; Siebert, Ursula

2016-01-01

The project conducts application-oriented research on impacts of underwater noise on marine vertebrates in the North and Baltic Seas. In distinct subprojects, the hearing sensitivity of harbor porpoises and gray seals as well as the acoustic tolerance limit of harbor porpoises to impulsive noise

Examination of Economic Feasibility of Nuclear Weapons in the Republic of Korea

Energy Technology Data Exchange (ETDEWEB)

Suh, Young A; Yim, Man Sung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2015-05-15

This observation implies that the popular view on nuclear weapons amongst Korean public is in part due to lack of knowledge about overall implications of possessing nuclear weapons. In this regard, pros and cons of nuclear weapons development need to be better characterized and understood by the public to support nuclear nonproliferation culture development. Noting lack of literature on characterizing the economics of nuclear weapons development, this study aims at performing economic feasibility analysis of nuclear weapons development in the ROK. For this purpose, an approach called Index technique based on the US experiences was applied to Korean historical data along with cost-benefit analysis and Multi-Criteria Decision Making Analysis. In this study, the scenario of nuclear weapons development against North Korean nuclear threat was compared with conventional weapons-based defense strategy. The comparison was based on cost benefit analysis and qualitative multi-criteria decision analysis. Results indicate that nuclear weapons development is not a desirable option. However, as this work was a rather simplistic academic exercise, further work is needed to support the outcome of the study. Outcome of these investigations would be useful for communication with the public regarding the need for nuclear weapons for national defense and to develop nuclear nonproliferation culture in the ROK.

Examination of Economic Feasibility of Nuclear Weapons in the Republic of Korea

International Nuclear Information System (INIS)

Suh, Young A; Yim, Man Sung

2015-01-01

This observation implies that the popular view on nuclear weapons amongst Korean public is in part due to lack of knowledge about overall implications of possessing nuclear weapons. In this regard, pros and cons of nuclear weapons development need to be better characterized and understood by the public to support nuclear nonproliferation culture development. Noting lack of literature on characterizing the economics of nuclear weapons development, this study aims at performing economic feasibility analysis of nuclear weapons development in the ROK. For this purpose, an approach called Index technique based on the US experiences was applied to Korean historical data along with cost-benefit analysis and Multi-Criteria Decision Making Analysis. In this study, the scenario of nuclear weapons development against North Korean nuclear threat was compared with conventional weapons-based defense strategy. The comparison was based on cost benefit analysis and qualitative multi-criteria decision analysis. Results indicate that nuclear weapons development is not a desirable option. However, as this work was a rather simplistic academic exercise, further work is needed to support the outcome of the study. Outcome of these investigations would be useful for communication with the public regarding the need for nuclear weapons for national defense and to develop nuclear nonproliferation culture in the ROK

Using the combination refraction-reflection solid to design omni-directional light source used in underwater wireless optical communication

Science.gov (United States)

Rao, Jionghui; Yao, Wenming; Wen, Linqiang

2015-10-01

Underwater wireless optical communication is a communication technology which uses laser as an information carrier and transmits data through water. Underwater wireless optical communication has some good features such as broader bandwidth, high transmission rate, better security, anti—interference performance. Therefore, it is promising to be widely used in the civil and military communication domains. It is also suitable for high-speed, short-range communication between underwater mobile vehicles. This paper presents a design approach of omni-directional light source used in underwater wireless optical communication, using TRACEPRO simulation tool to help design a combination solid composed of the lens, conical reflector and parabolic reflector, and using the modulated DPSS green laser in the transmitter module to output the laser beam in small divergence angles, after expanded by the combination refraction-reflection solid, the angle turns into a space divergence angle of 2π, achieving the omni-directional light source of hemisphere space, and test in the air and underwater, the result shows that the effect is fine. This paper analyzes the experimental test in the air and water, in order to make further improvement of the uniformity of light distribution, we optimize the reflector surface parameters of combination refraction-reflection solid and test in the air and water. The result shows that omni-directional light source used in underwater wireless optical communication optimized could achieve the uniformity of light distribution of underwater space divergence angle of 2π. Omni-directional light source used in underwater wireless optical communication designed in this paper has the characteristics of small size and uniformity of light distribution, it is suitable for application between UUVs, AUVs, Swimmer Delivery Vehicles (SDVs) and other underwater vehicle fleet, it realizes point-to-multipoint communications.

Underwater image enhancement based on the dark channel prior and attenuation compensation

Science.gov (United States)

Guo, Qingwen; Xue, Lulu; Tang, Ruichun; Guo, Lingrui

2017-10-01

Aimed at the two problems of underwater imaging, fog effect and color cast, an Improved Segmentation Dark Channel Prior (ISDCP) defogging method is proposed to solve the fog effects caused by physical properties of water. Due to mass refraction of light in the process of underwater imaging, fog effects would lead to image blurring. And color cast is closely related to different degree of attenuation while light with different wavelengths is traveling in water. The proposed method here integrates the ISDCP and quantitative histogram stretching techniques into the image enhancement procedure. Firstly, the threshold value is set during the refinement process of the transmission maps to identify the original mismatching, and to conduct the differentiated defogging process further. Secondly, a method of judging the propagating distance of light is adopted to get the attenuation degree of energy during the propagation underwater. Finally, the image histogram is stretched quantitatively in Red-Green-Blue channel respectively according to the degree of attenuation in each color channel. The proposed method ISDCP can reduce the computational complexity and improve the efficiency in terms of defogging effect to meet the real-time requirements. Qualitative and quantitative comparison for several different underwater scenes reveals that the proposed method can significantly improve the visibility compared with previous methods.

Does nuclear power lead to nuclear weapons

International Nuclear Information System (INIS)

Prawitz, J.

1977-01-01

It is pointed out that 'reactor grade' plutonium usually contains about 30 % Pu240 and is unsuitable for weapons. While it is possible to obtain an explosion, it is more difficult to initiate one and its effect, which will be considerably less than with bomb grade plutonium, is difficult to predict. The critical mass will be larger and more cooling required. The proliferation problem is then discussed and the four aspects, vertical, horizontal, sub-national and revolutionary, mentioned. In connection with nuclear power it is the second and third aspects which are of interest. In discussing the possibility of terrorist groups obtaining plutonium, a study by the Swedish Defence Research Institute is quoted as estimating that 10-20 qualified specialists and several years secret preparation would be necessary to make a nuclear weapon. Other authors, e.g. Ted Taylor, have maintained that it would be much easier, but examples of 'student designs' are primitive and unlikely to detonate. Even so, it is emphasised that safeguards and physical security are necessary. Horizontal proliferation is a more real problem and the NPT and IAEA safeguards are discussed in this connection. In conclusion the question of whether the proliferation of nuclear weapons via nuclear power can be prevented cannot be answered with a clear yes or no. Certain states may use nuclear weapon potential as a bargaining factor. However the decision to acquire nuclear weapons is political and while a nuclear power industry would be of help, it would not be decisively so. (JIW)

Re-examining the 1996 ICJ Advisory Opinion: Concerning the Legality of Nuclear Weapons

Directory of Open Access Journals (Sweden)

Jasjit Singh

2012-10-01

Full Text Available The primary objections raised against total elimination of nuclear weapons are built around a few arguments mostly of non-technical nature.Nuclear weapons and the strategies for their use have resulted in the establishment of a vicious circle within which the international community is trapped.The argument that the world will be unsafe without nuclear weapons is only meant to further the narrow self-interest of the nuclear weapon states and their allies.The World Court’s far-reaching 1996 advisory opinion concluded that almost any use or threat of use of nuclear weapons would violate international humanitarian law and law applicable in armed conflict, undermining most claims of nuclear weapon states regarding the legitimacy of possession, use or threat of use of nuclear weapons. The next logical step would be an initiative for a nuclear convention banning the use and threat of use of nuclear weapons in Asia and the adjoining oceans. But as long as the dominant elites in society and the nation-state believe in the utility of nuclear weapons for national security or as the currency of power, abolition of nuclear weapons will remain a mirage.

Autopilot Using Differential Thrust for ARIES Autonomous Underwater Vehicle

National Research Council Canada - National Science Library

Sarton, Christopher

2003-01-01

.... Unfortunately, communication antennas must point to specific satellites in this system and thus underwater vehicles must steer a specific course on the surface during the communication process...

SOUNET: Self-Organized Underwater Wireless Sensor Network

Directory of Open Access Journals (Sweden)

Hee-won Kim

2017-02-01

Full Text Available In this paper, we propose an underwater wireless sensor network (UWSN named SOUNET where sensor nodes form and maintain a tree-topological network for data gathering in a self-organized manner. After network topology discovery via packet flooding, the sensor nodes consistently update their parent node to ensure the best connectivity by referring to the timevarying neighbor tables. Such a persistent and self-adaptive method leads to high network connectivity without any centralized control, even when sensor nodes are added or unexpectedly lost. Furthermore, malfunctions that frequently happen in self-organized networks such as node isolation and closed loop are resolved in a simple way. Simulation results show that SOUNET outperforms other conventional schemes in terms of network connectivity, packet delivery ratio (PDR, and energy consumption throughout the network. In addition, we performed an experiment at the Gyeongcheon Lake in Korea using commercial underwater modems to verify that SOUNET works well in a real environment.

SOUNET: Self-Organized Underwater Wireless Sensor Network.

Science.gov (United States)

Kim, Hee-Won; Cho, Ho-Shin

2017-02-02

In this paper, we propose an underwater wireless sensor network (UWSN) named SOUNET where sensor nodes form and maintain a tree-topological network for data gathering in a self-organized manner. After network topology discovery via packet flooding, the sensor nodes consistently update their parent node to ensure the best connectivity by referring to the timevarying neighbor tables. Such a persistent and self-adaptive method leads to high network connectivity without any centralized control, even when sensor nodes are added or unexpectedly lost. Furthermore, malfunctions that frequently happen in self-organized networks such as node isolation and closed loop are resolved in a simple way. Simulation results show that SOUNET outperforms other conventional schemes in terms of network connectivity, packet delivery ratio (PDR), and energy consumption throughout the network. In addition, we performed an experiment at the Gyeongcheon Lake in Korea using commercial underwater modems to verify that SOUNET works well in a real environment.

Underwater noise modelling for environmental impact assessment

Energy Technology Data Exchange (ETDEWEB)

Farcas, Adrian [Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT (United Kingdom); Thompson, Paul M. [Lighthouse Field Station, Institute of Biological and Environmental Sciences, University of Aberdeen, Cromarty IV11 8YL (United Kingdom); Merchant, Nathan D., E-mail: nathan.merchant@cefas.co.uk [Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT (United Kingdom)

2016-02-15

Assessment of underwater noise is increasingly required by regulators of development projects in marine and freshwater habitats, and noise pollution can be a constraining factor in the consenting process. Noise levels arising from the proposed activity are modelled and the potential impact on species of interest within the affected area is then evaluated. Although there is considerable uncertainty in the relationship between noise levels and impacts on aquatic species, the science underlying noise modelling is well understood. Nevertheless, many environmental impact assessments (EIAs) do not reflect best practice, and stakeholders and decision makers in the EIA process are often unfamiliar with the concepts and terminology that are integral to interpreting noise exposure predictions. In this paper, we review the process of underwater noise modelling and explore the factors affecting predictions of noise exposure. Finally, we illustrate the consequences of errors and uncertainties in noise modelling, and discuss future research needs to reduce uncertainty in noise assessments.

Underwater noise modelling for environmental impact assessment

International Nuclear Information System (INIS)

Farcas, Adrian; Thompson, Paul M.; Merchant, Nathan D.

2016-01-01

Assessment of underwater noise is increasingly required by regulators of development projects in marine and freshwater habitats, and noise pollution can be a constraining factor in the consenting process. Noise levels arising from the proposed activity are modelled and the potential impact on species of interest within the affected area is then evaluated. Although there is considerable uncertainty in the relationship between noise levels and impacts on aquatic species, the science underlying noise modelling is well understood. Nevertheless, many environmental impact assessments (EIAs) do not reflect best practice, and stakeholders and decision makers in the EIA process are often unfamiliar with the concepts and terminology that are integral to interpreting noise exposure predictions. In this paper, we review the process of underwater noise modelling and explore the factors affecting predictions of noise exposure. Finally, we illustrate the consequences of errors and uncertainties in noise modelling, and discuss future research needs to reduce uncertainty in noise assessments.

Cymbal and BB underwater transducers and arrays

Energy Technology Data Exchange (ETDEWEB)

Newnham, R.E.; Zhang, J.; Alkoy, S.; Meyer, R.; Hughes, W.J.; Hladky-Hennion, A.C.; Cochran, J.; Markley, D. [Materials Research Laboratory, Penn State University, University Park, PA 16802 (United States)

2002-09-01

The cymbal is a miniaturized class V flextensional transducer that was developed for use as a shallow water sound projector and receiver. Single elements are characterized by high Q, low efficiency, and medium power output capability. Its low cost and thin profile allow the transducer to be assembled into large flexible arrays. Efforts were made to model both single elements and arrays using the ATILA code and the integral equation formulation (EQI).Millimeter size microprobe hydrophones (BBs) have been designed and fabricated from miniature piezoelectric hollow ceramic spheres for underwater applications such as mapping acoustic fields of projectors, and flow noise sensors for complex underwater structures. Green spheres are prepared from soft lead zirconate titanate powders using a coaxial nozzle slurry process. A compact hydrophone with a radially-poled sphere is investigated using inside and outside electrodes. Characterization of these hydrophones is done through measurement of hydrostatic piezoelectric charge coefficients, free field voltage sensitivities and directivity beam patterns. (orig.)

Underwater noise from a wave energy converter

DEFF Research Database (Denmark)

Tougaard, Jakob

A recent addition to the anthropogenic sources of underwater noise is offshore wave energy converters. Underwater noise was recorded from the Wavestar wave energy converter located at Hastholm, Denmark (57°7.73´N, 8°37.23´E). The Wavestar is a full-scale test and demonstration converter...... in full operation and start and stop of the converter. Median broad band (10 Hz – 20 kHz) sound pressure level (Leq) was 123 dB re. 1 Pa, irrespective of status of the wave energy converter (stopped, running or starting/stopping). The most pronounced peak in the third-octave spectrum was in the 160 Hz...... significant noise above ambient could be detected above the 250 Hz band. The absolute increase in noise above ambient was very small. L50 third-octave levels in the four bands with the converter running were thus only 1-2 dB above ambient L50 levels. The noise recorded 25 m from the wave energy converter...

The spread of nuclear weapons among nations: militarization or development

International Nuclear Information System (INIS)

Khan, A.Q.

1986-01-01

The paper reviews nuclear proliferation among nations. Nuclear weapons promotion and proliferation are discussed, including both motivation and lack of motivation to manufacture nuclear weapons. The failure of the Non-Proliferation Treaty is examined with respect to vertical and horizontal proliferation, and the containment of horizontal proliferation. Risks of nuclear war by accident are outlined, as well as nuclear weapon development. (UK)

Weapon plutonium in accelerator driven power system

International Nuclear Information System (INIS)

Shvedov, O.V.; Murin, B.P.; Kochurov, B.P.; Shubin, Yu.M.; Volk, V.I.; Bogdanov, P.V.

1997-01-01

Accelerator Driven Systems are planned to be developed for the use (or destruction) of dozens of tons of weapon-grade Plutonium (W-Pu) resulted from the reducing of nuclear weapons. In the paper are compared the parameters of various types of accelerators, the physical properties of various types of targets and blankets, and the results of fuel cycle simulation. Some economical aspects are also discussed

The Uncertain Consequences of Nuclear Weapons Use

Science.gov (United States)

2015-04-15

this genre is the venerable, and classified, official “bible” of nuclear weapons effects, Capabilities of Nuclear Weapons. Widely referred to by...weekly comic Shukan Shonen Jampu and was later made into several film versions, a television drama series, and ten books, which follow Gen’s...civilized behavior. The film , distributed internationally and shown on Soviet television, was widely discussed in the United States and both depressed

20-meter underwater wireless optical communication link with 15 Gbps data rate

KAUST Repository

Shen, Chao

2016-10-24

The video streaming, data transmission, and remote control in underwater call for high speed (Gbps) communication link with a long channel length (∼10 meters). We present a compact and low power consumption underwater wireless optical communication (UWOC) system utilizing a 450-nm laser diode (LD) and a Si avalanche photodetector. With the LD operating at a driving current of 80 mA with an optical power of 51.3 mW, we demonstrated a high-speed UWOC link offering a data rate up to 2 Gbps over a 12-meter-long, and 1.5 Gbps over a record 20-meter-long underwater channel. The measured bit-error rate (BER) are 2.8 × 10-5, and 3.0 × 10-3, respectively, which pass well the forward error correction (FEC) criterion. © 2016 Optical Society of America.

20-meter underwater wireless optical communication link with 15 Gbps data rate

KAUST Repository

Shen, Chao; Guo, Yong; Oubei, Hassan M.; Ng, Tien Khee; Liu, Guangyu; Park, Kihong; Ho, Kang-Ting; Alouini, Mohamed-Slim; Ooi, Boon S.

2016-01-01

The video streaming, data transmission, and remote control in underwater call for high speed (Gbps) communication link with a long channel length (∼10 meters). We present a compact and low power consumption underwater wireless optical communication (UWOC) system utilizing a 450-nm laser diode (LD) and a Si avalanche photodetector. With the LD operating at a driving current of 80 mA with an optical power of 51.3 mW, we demonstrated a high-speed UWOC link offering a data rate up to 2 Gbps over a 12-meter-long, and 1.5 Gbps over a record 20-meter-long underwater channel. The measured bit-error rate (BER) are 2.8 × 10-5, and 3.0 × 10-3, respectively, which pass well the forward error correction (FEC) criterion. © 2016 Optical Society of America.

Status on underwater plasma arc cutting in KHI, 3

International Nuclear Information System (INIS)

Abe, Tadashi; Aota, Toshiichi; Nishizaki, Tadashi; Nakayama, Shigeru; Yamashita, Seiji

1983-01-01

In Kawasaki Heavy Industries, Ltd., the development of a remote dismantling system by underwater plasma arc cutting process has been advanced, expecting its application to the dismantling and removal of nuclear reactor facilities. In the previous two reports, the fundamental experimental results such as the comparison of the cutting capability in air and in water were shown, but this time, the remote automatic cutting of wedge-shaped specimens was carried out, using a newly installed manipulator for underwater works, therefore its outline is reported. Also the cutting experiment by overhead position and vertical position was performed by using the same equipment, and comparison was made with the cutting capability by downhand and horizontal positions. It is important to grasp the cutting characteristics in the case of upward advancing and downward advancing cuttings by overhead and vertical positions when the cutting of pressure vessels and horizontal pipes into rings is supposed. The experimental apparatus, the cutting conditions, the testing method and the test results of the cutting capability test, the test of changing direction during cutting, and the remote cutting of pipes into rings are described. The underwater plasma arc cutting can cut all metals, the cutting speed is relatively high, and the apparatus is simple and compact. (Kako, I.)

In-air versus underwater comparison of 3D reconstruction accuracy using action sport cameras.

Science.gov (United States)

Bernardina, Gustavo R D; Cerveri, Pietro; Barros, Ricardo M L; Marins, João C B; Silvatti, Amanda P

2017-01-25

Action sport cameras (ASC) have achieved a large consensus for recreational purposes due to ongoing cost decrease, image resolution and frame rate increase, along with plug-and-play usability. Consequently, they have been recently considered for sport gesture studies and quantitative athletic performance evaluation. In this paper, we evaluated the potential of two ASCs (GoPro Hero3+) for in-air (laboratory) and underwater (swimming pool) three-dimensional (3D) motion analysis as a function of different camera setups involving the acquisition frequency, image resolution and field of view. This is motivated by the fact that in swimming, movement cycles are characterized by underwater and in-air phases what imposes the technical challenge of having a split volume configuration: an underwater measurement volume observed by underwater cameras and an in-air measurement volume observed by in-air cameras. The reconstruction of whole swimming cycles requires thus merging of simultaneous measurements acquired in both volumes. Characterizing and optimizing the instrumental errors of such a configuration makes mandatory the assessment of the instrumental errors of both volumes. In order to calibrate the camera stereo pair, black spherical markers placed on two calibration tools, used both in-air and underwater, and a two-step nonlinear optimization were exploited. The 3D reconstruction accuracy of testing markers and the repeatability of the estimated camera parameters accounted for system performance. For both environments, statistical tests were focused on the comparison of the different camera configurations. Then, each camera configuration was compared across the two environments. In all assessed resolutions, and in both environments, the reconstruction error (true distance between the two testing markers) was less than 3mm and the error related to the working volume diagonal was in the range of 1:2000 (3×1.3×1.5m 3 ) to 1:7000 (4.5×2.2×1.5m 3 ) in agreement with the

The prevention of geographical proliferation of nuclear weapons: Nuclear-weapon-free zones and zones of peace in the Southern hemisphere

International Nuclear Information System (INIS)

Fujita, E.

1989-01-01

It is understandable that many Non-Nuclear Weapons States (NNWS) worry about the dangers of further geographical or spatial proliferation of nuclear weapons, as well as the extension to their regions of rivalries that are foreign to them. In this regard, there has been since the 1950's a number of proposals and initiatives to turn specific regions into nuclear-weapons-free zones and zones of peace in order to prevent or reduce the above mentioned threats. Although differences exits between the concepts of nuclear-weapon-free-zones and zones of peace as well as among the various NWFZ and ZP, inter se, they do share a common feature insofar as they represent a regional approach to the question of curbing the arms race, especially the nuclear one. This study will address some of these initiatives, examine their specific characteristics and assess their role in the prevention of the geographical proliferation of nuclear weapons. Among the relevant existing initiatives, those situated in the Southern Hemisphere offer an interesting focus of attention, in view of the fact that, together, they form a sort of a contiguous geographical area encompassing virtually half of the globe. The regions covered are the Antarctic, Latin American, South Pacific, South Atlantic and Indian Oceans. The first three have been established as nuclear-weapons-free-zones and the last two are in the process of being turned into zones of peace. The aim of this study is to compare similarities and differences among them and to identify the factors that condition their efficiency. By understanding their usefulness and their weaknesses, one many eventually construct useful paradigms for further regional initiatives to curb the arms race, specially the nuclear one

Nuclear weapons in the India-Pakistan context

International Nuclear Information System (INIS)

Sanjay Badri-Maharaj

2002-01-01

This thesis deals with the possible employment of nuclear weapons in the ongoing confrontation between India and Pakistan. After reviewing the nuclear capabilities of both Indian and Pakistan and assessing their possible delivery systems, this dissertation explores the emerging picture regarding the Indian and Pakistani nuclear doctrines. It is argued that, after exploring the current structure of the armed forces in both countries and after analyzing the theatres of operations, it is highly unlikely that either country seeks to employ nuclear weapons in a tactical, battlefield role. It is also argued that neither India or Pakistan is making an effort to evolve a nuclear war-fighting doctrine. Moreover, it is shown that nuclear weapons have simply led to a re-thinking of military tactics on the part of India so as to minimize the chance of a nuclear strike by limiting the aims and objectives of any Indian military action. In stark contrast, it is shown that South Asian cities present far more lucrative targets for nuclear strikes. As a result of this and the geographic and tactical limitations of South Asian battlefields, it is argued that both India and Pakistan have based their fledgling nuclear strategies around a 'city-busting' concept. The existing command and control systems in both countries are examined and found to be adequate if both countries adopt a strict 'second-strike' approach to the employment of nuclear weapons. It is further argued that nuclear weapons, while limiting the scale of any future India-Pakistan war, will not play a major role in preventing a conflict between the two countries. Rather, the basic operational parity that exists between the two countries in terms of their conventional forces is responsible for preventing the outbreak of war. The thesis also briefly explores the rationale behind the acquisition of nuclear weapons in both countries and on their basic security perceptions. The issue of confidence building measures and the

77 FR 59891 - Proposed Information Collection; Comment Request; Chemical Weapons Convention Declaration and...

Science.gov (United States)

2012-10-01

... Request; Chemical Weapons Convention Declaration and Report Handbook and Forms AGENCY: Bureau of Industry.... Abstract The Chemical Weapons Convention Implementation Act of 1998 and Commerce Chemical Weapons... Chemical Weapons Convention (CWC), an international arms control treaty. II. Method of Collection Submitted...

Geographical positioning using laser optical instrument for near-shore underwater archaeological explorations

Digital Repository Service at National Institute of Oceanography (India)

Ganesan, P.

carefully identified comers of the underwater artifacts) is found to be more accurate, faster, and reliable. This method can be effectively used only for shallow water near shore underwater archaeo- GLIMPSES OF MARINE ARCHAEOLOGY IN INDIA logical... Trak (placed over selected ground controi station) and a multi-prism (placed over carefully identified comers of the artifact). The standard survey procedures prescribed in the Laser Trak operation manual (Make III model) were used to carry out...

Contour Tracking Control for the REMUS Autonomous Underwater Vehicle

National Research Council Canada - National Science Library

Van Reet, Alan R

2005-01-01

In the interest of enhancing the capabilities of autonomous underwater vehicles used in US Naval Operations, controlling vehicle position to follow depth contours presents exciting potential for navigation...

50 kW laser weapon demonstrator of Rheinmetall Waffe munition

Science.gov (United States)

Ludewigt, K.; Riesbeck, Th.; Graf, A.; Jung, M.

2013-10-01

We will present the setup of a 50 kW Laser Weapon Demonstrator (LWD) and results achieved with this system. The LWD is a ground based Air Defence system consisting of a Skyguard sensor unit for target acquisition and two laser equipped weapon turrets. The weapon turrets used are standard air defence turrets of Rheinmetall Air Defence which were equipped with several 10 kW Laser Weapon Modules (LWM). Each LWM consists of one 10 kW fiber laser and a beam forming unit (BFU). Commercial of the shelf fiber laser were modified for our defence applications. The BFU providing diffraction limited beam focusing, target imaging and fine tracking of the target was developed. The LWD was tested in a firing campaign at Rheinmetall test ground in Switzerland. All laser beams of both weapon turrets were superimposed on stationary and dynamic targets. Test results of the LWD for the scenarios Air Defence and C-RAMM (counter rockets, artillery, mortar and missiles) will be presented. An outlook for the next development stage towards a 100 kW class laser weapon on RWM will be given.

Passive aquatic listener (PAL): An adoptive underwater acoustic recording system for the marine environment

International Nuclear Information System (INIS)

Anagnostou, Marios N.; Nystuen, Jeffrey A.; Anagnostou, Emmanouil N.; Papadopoulos, Anastasios; Lykousis, Vassilios

2011-01-01

The ambient sound field in the ocean is a combination of natural and manmade sounds. Consequently, the interpretation of the ambient sound field can be used to quantify these processes. In the frequency range from 1 to 50 kHz, the general character of ocean ambient sound is a slowly changing background that is closely associated with local wind speed, interspersed with shorter time scale events such as rain storms, ships and animal calls. At lower frequencies the underwater ambient sound budget includes geologically generated sound activities including underwater volcanic eruptions, seismic and seepage faults that generate bubbles, etc. that can also potentially be classified and quantified. Acoustic data are collected on hydrophones. Hydrophones are simple, robust sensors that can be deployed on most ocean instrumentation systems including surface or sub-surface moorings, bottom mounted systems, drifters, ARGO floats or autonomous underwater platforms. A dedicated oceanic underwater recorder called a passive acoustic listener (PAL) has been developed. A principal issue is to accurately distinguish different sound sources so that they can be quantified as part of a sound budget, and then quantified if appropriate. Based on ongoing data collected from the Poseidon II network the retrieval potential of multi-parameters from underwater sound, including meteorological (i.e., precipitation and winds) and in general geophysical, anthropogenetic (i.e., ships, submarines, etc.) and biological (whales, etc.) sources is presented.

Passive aquatic listener (PAL): An adoptive underwater acoustic recording system for the marine environment

Energy Technology Data Exchange (ETDEWEB)

Anagnostou, Marios N., E-mail: managnostou@ath.hcmr.g [Hellenic Center for Marine Research, Department of Inland Waters, Anavissos (Greece); Nystuen, Jeffrey A. [Hellenic Center for Marine Research, Department of Inland Waters, Anavissos (Greece); Applied Physics Laboratory, University of Washington, Seattle, WA (United States); Anagnostou, Emmanouil N. [Hellenic Center for Marine Research, Department of Inland Waters, Anavissos (Greece); Department of Civil and Environmental Engineering, University of Connecticut, CT (United States); Papadopoulos, Anastasios [Hellenic Center for Marine Research, Department of Inland Waters, Anavissos (Greece); Lykousis, Vassilios [Hellenic Center for Marine Research, Department of Oceanography, Anavissos (Greece)

2011-01-21

The ambient sound field in the ocean is a combination of natural and manmade sounds. Consequently, the interpretation of the ambient sound field can be used to quantify these processes. In the frequency range from 1 to 50 kHz, the general character of ocean ambient sound is a slowly changing background that is closely associated with local wind speed, interspersed with shorter time scale events such as rain storms, ships and animal calls. At lower frequencies the underwater ambient sound budget includes geologically generated sound activities including underwater volcanic eruptions, seismic and seepage faults that generate bubbles, etc. that can also potentially be classified and quantified. Acoustic data are collected on hydrophones. Hydrophones are simple, robust sensors that can be deployed on most ocean instrumentation systems including surface or sub-surface moorings, bottom mounted systems, drifters, ARGO floats or autonomous underwater platforms. A dedicated oceanic underwater recorder called a passive acoustic listener (PAL) has been developed. A principal issue is to accurately distinguish different sound sources so that they can be quantified as part of a sound budget, and then quantified if appropriate. Based on ongoing data collected from the Poseidon II network the retrieval potential of multi-parameters from underwater sound, including meteorological (i.e., precipitation and winds) and in general geophysical, anthropogenetic (i.e., ships, submarines, etc.) and biological (whales, etc.) sources is presented.

Development of underwater laser cladding and underwater laser seal welding techniques for reactor components

International Nuclear Information System (INIS)

Hino, Takehisa; Tamura, Masataka; Tanaka, Yoshimi; Kouno, Wataru; Makino, Yoshinobu; Kawano, Shohei; Matsunaga, Keiji

2009-01-01

Stress corrosion cracking (SCC) has been reported at the aged components in many nuclear power plants. Toshiba has been developing the underwater laser welding. This welding technique can be conducted without draining the water in the reactor vessel. It is beneficial for workers not to exposure the radiation. The welding speed can be attaining twice as fast as that of Gas Tungsten Arc Welding (GTAW). The susceptibility of SCC can also be lower than the Alloy 600 base metal. (author)

Nuclear-weapon-free zones: Pursuing security, region by region. Conference of States Parties and Signatories of treaties that establish nuclear-weapon-free zones

International Nuclear Information System (INIS)

ElBaradei, M.

2005-01-01

The development of nuclear-weapon-free zones, over the past four decades, is a testament to what nations can do, region by region, to achieve common security objectives. In fact, when considering the history of nuclear non-proliferation efforts, it might be said that here in Mexico City is w here it all began . The 1967 Treaty of Tlatelolco was the first multilateral treaty to establish a region free of nuclear weapons and a requirement for comprehensive IAEA safeguards for its parties - and clearly gave impetus to the conclusion of the Treaty on the Non-Proliferation of Nuclear Weapons. Nuclear-weapon-free zones provide tangible security benefits. They help to reassure the larger international community of the peaceful nuclear intentions of countries in these regions. They provide their members with security assurances against the use, or threat of use, of nuclear weapons by a nuclear-weapon State. They include control mechanisms for dealing with non-compliance in a regional setting. And in all cases, they prohibit the development, stationing or testing of nuclear weapons in their respective regions. An important benefit of these zones is that they open a forum for expanded regional dialogue on issues of security. Because the causes of insecurity vary from region to region, security solutions do not come in a 'one-size-fits-all' package. It is for this reason that regional dialogues, as we see in the nuclear-weapon-free zones, are so beneficial. It is clear that such treaties, and such security dialogues, would be invaluable in other areas of the world, such as the Middle East and the Korean Peninsula. Since the end of the Cold War, the international security landscape has undergone dramatic changes. For example, the rise in terrorism, the discovery of clandestine nuclear programmes, and the emergence of covert nuclear procurement networks have heightened our awareness of vulnerabilities in the nuclear non-proliferation regime. This statement focuses on two issues

Specialization for underwater hearing by the tympanic middle ear of the turtle, Trachemys scripta elegans

DEFF Research Database (Denmark)

Christensen-Dalsgaard, J.; Brandt, Christian; Willis, K. L.

2012-01-01

Turtles, like other amphibious animals, face a trade-off between terrestrial and aquatic hearing. We used laser vibrometry and auditory brainstem responses to measure their sensitivity to vibration stimuli and to airborne versus underwater sound. Turtles are most sensitive to sound underwater, an...

Latest Trends in the Monitoring of Ships’s Hull Underwater Part and Analysis of Its Effectiveness

OpenAIRE

Urbahs, A; Carjova, K; Vulans, P; Straume, R

2012-01-01

Ship operation is not possible without regular maintenance, inspection and certification, established by international and domestic law, where one of the main goals is an effective operation of a ship. To achieve this, it is important to reduce time and costs involved in carrying out the surveys. This paper explores the law under which it’s required for ship to have inspection of underwater part; identifies problems of ship’s hull underwater part; analyze latest trends in ship's hull underwat...

Dynamics of underwater legged locomotion: modeling and experiments on an octopus-inspired robot.

Science.gov (United States)

Calisti, M; Corucci, F; Arienti, A; Laschi, C

2015-07-30

This paper studies underwater legged locomotion (ULL) by means of a robotic octopus-inspired prototype and its associated model. Two different types of propulsive actions are embedded into the robot model: reaction forces due to leg contact with the ground and hydrodynamic forces such as the drag arising from the sculling motion of the legs. Dynamic parameters of the model are estimated by means of evolutionary techniques and subsequently the model is exploited to highlight some distinctive features of ULL. Specifically, the separation between the center of buoyancy (CoB)/center of mass and density affect the stability and speed of the robot, whereas the sculling movements contribute to propelling the robot even when its legs are detached from the ground. The relevance of these effects is demonstrated through robotic experiments and model simulations; moreover, by slightly changing the position of the CoB in the presence of the same feed-forward activation, a number of different behaviors (i.e. forward and backward locomotion at different speeds) are achieved.

Burning weapons-grade plutonium in reactors

International Nuclear Information System (INIS)

Newman, D.F.

1993-06-01

As a result of massive reductions in deployed nuclear warheads, and their subsequent dismantlement, large quantities of surplus weapons- grade plutonium will be stored until its ultimate disposition is achieved in both the US and Russia. Ultimate disposition has the following minimum requirements: (1) preclude return of plutonium to the US and Russian stockpiles, (2) prevent environmental damage by precluding release of plutonium contamination, and (3) prevent proliferation by precluding plutonium diversion to sub-national groups or nonweapons states. The most efficient and effective way to dispose of surplus weapons-grade plutonium is to fabricate it into fuel and use it for generation of electrical energy in commercial nuclear power plants. Weapons-grade plutonium can be used as fuel in existing commercial nuclear power plants, such as those in the US and Russia. This recovers energy and economic value from weapons-grade plutonium, which otherwise represents a large cost liability to maintain in safeguarded and secure storage. The plutonium remaining in spent MOX fuel is reactor-grade, essentially the same as that being discharged in spent UO 2 fuels. MOX fuels are well developed and are currently used in a number of LWRs in Europe. Plutonium-bearing fuels without uranium (non-fertile fuels) would require some development. However, such non-fertile fuels are attractive from a nonproliferation perspective because they avoid the insitu production of additional plutonium and enhance the annihilation of the plutonium inventory on a once-through fuel cycle

Accuracy Assessment of Underwater Photogrammetric Three Dimensional Modelling for Coral Reefs

Science.gov (United States)

Guo, T.; Capra, A.; Troyer, M.; Gruen, A.; Brooks, A. J.; Hench, J. L.; Schmitt, R. J.; Holbrook, S. J.; Dubbini, M.

2016-06-01

Recent advances in automation of photogrammetric 3D modelling software packages have stimulated interest in reconstructing highly accurate 3D object geometry in unconventional environments such as underwater utilizing simple and low-cost camera systems. The accuracy of underwater 3D modelling is affected by more parameters than in single media cases. This study is part of a larger project on 3D measurements of temporal change of coral cover in tropical waters. It compares the accuracies of 3D point clouds generated by using images acquired from a system camera mounted in an underwater housing and the popular GoPro cameras respectively. A precisely measured calibration frame was placed in the target scene in order to provide accurate control information and also quantify the errors of the modelling procedure. In addition, several objects (cinder blocks) with various shapes were arranged in the air and underwater and 3D point clouds were generated by automated image matching. These were further used to examine the relative accuracy of the point cloud generation by comparing the point clouds of the individual objects with the objects measured by the system camera in air (the best possible values). Given a working distance of about 1.5 m, the GoPro camera can achieve a relative accuracy of 1.3 mm in air and 2.0 mm in water. The system camera achieved an accuracy of 1.8 mm in water, which meets our requirements for coral measurement in this system.

Underwater target positioning with a single acoustic sensor

Digital Repository Service at National Institute of Oceanography (India)

David, M-S; Pascoal, A.M.; Joaquin, A.

The availability of reliable underwater positioning systems to localize one or more vehicles simultaneously based on information received on-board a support ship or an autonomous surface vessel is key to the operation of some classes of AUVs...

Underwater microwave ignition of hydrophobic thermite powder enabled by the bubble-marble effect

International Nuclear Information System (INIS)

Meir, Yehuda; Jerby, Eli

2015-01-01

Highly energetic thermite reactions could be useful for a variety of combustion and material-processing applications, but their usability is yet limited by their hard ignition conditions. Furthermore, in virtue of their zero-oxygen balance, exothermic thermite reactions may also occur underwater. However, this feature is also hard to utilize because of the hydrophobic properties of the thermite powder, and its tendency to agglomerate on the water surface rather than to sink into the water. The recently discovered bubble-marble (BM) effect enables the insertion and confinement of a thermite-powder batch into water by a magnetic field. Here, we present a phenomenon of underwater ignition of a thermite-BM by localized microwaves. The thermite combustion underwater is observed in-situ, and its microwave absorption and optical spectral emission are detected. The vapour pressure generated by the thermite reaction is measured and compared to theory. The combustion products are examined ex-situ by X-ray photo-electron spectroscopy which verifies the thermite reaction. Potential applications of this underwater combustion effect are considered, e.g., for detonation, wet welding, thermal drilling, material processing, thrust generation, and composite-material production, also for other oxygen-free environments

Underwater microwave ignition of hydrophobic thermite powder enabled by the bubble-marble effect

Energy Technology Data Exchange (ETDEWEB)

Meir, Yehuda; Jerby, Eli, E-mail: jerby@eng.tau.ac.il [Faculty of Engineering, Tel Aviv University, Ramat Aviv 6997801 (Israel)

2015-08-03

Highly energetic thermite reactions could be useful for a variety of combustion and material-processing applications, but their usability is yet limited by their hard ignition conditions. Furthermore, in virtue of their zero-oxygen balance, exothermic thermite reactions may also occur underwater. However, this feature is also hard to utilize because of the hydrophobic properties of the thermite powder, and its tendency to agglomerate on the water surface rather than to sink into the water. The recently discovered bubble-marble (BM) effect enables the insertion and confinement of a thermite-powder batch into water by a magnetic field. Here, we present a phenomenon of underwater ignition of a thermite-BM by localized microwaves. The thermite combustion underwater is observed in-situ, and its microwave absorption and optical spectral emission are detected. The vapour pressure generated by the thermite reaction is measured and compared to theory. The combustion products are examined ex-situ by X-ray photo-electron spectroscopy which verifies the thermite reaction. Potential applications of this underwater combustion effect are considered, e.g., for detonation, wet welding, thermal drilling, material processing, thrust generation, and composite-material production, also for other oxygen-free environments.

Survey and Recording Technologies in Italian Underwater Cultural Heritage: Research and Public Access Within the Framework of the 2001 UNESCO Convention

Science.gov (United States)

Secci, Massimiliano

2017-08-01

The 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage is slowly but peremptorily becoming a standard reference tool for underwater archaeology and underwater cultural heritage management. The many provisions included within the Convention touch on many aspects that are key to an effective protection and promotion of the underwater cultural heritage. Within the web of these provisions many aspects are gaining consideration and driving research in underwater archaeology worldwide. These provisions, when seen within a wider frame of social, economical and technological dynamics, pinpoint many aspects requiring further scrutiny from the disciplinary circle. In the framework of the 2001 UNESCO Convention, this article will analyze the path traveled in technological acquisition in the practice of Italian underwater archaeology and how this has affected the approach to underwater cultural heritage management, particularly highlighting how this process has been further influenced by the adoption in 2001 of the Convention and Italy's ratification of it in 2010.

Males that drop a sexually selected weapon grow larger testes.

Science.gov (United States)

Joseph, Paul N; Emberts, Zachary; Sasson, Daniel A; Miller, Christine W

2018-01-01

Costly sexually selected weapons are predicted to trade off with postcopulatory traits, such as testes. Although weapons can be important for achieving access to females, individuals of some species can permanently drop (i.e. autotomize) their weapons, without regeneration, to escape danger. We capitalized on this natural behavior to experimentally address whether the loss of a sexually selected weapon leads to increased testes investment in the leaf-footed cactus bug, Narnia femorata Stål (Hemiptera: Coreidae). In a second experiment, we measured offspring production for males that lost a weapon during development. As predicted, males that dropped a hind limb during development grew significantly larger testes than the control treatments. Hind-limb autotomy did not result in the enlargement of other nearby traits. Our results are the first to experimentally demonstrate that males compensate for natural weapon loss by investing more in testes. In a second experiment we found that females paired with males that lost a hind limb had 40% lower egg hatching success than females paired with intact males, perhaps because of lower mating receptivity to males with a lost limb. Importantly, in those cases where viable offspring were produced, males missing a hind limb produced 42% more offspring than males with intact limbs. These results suggest that the loss of a hind-limb weapon can, in some cases, lead to greater fertilization success. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Particle Filter for Fault Diagnosis and Robust Navigation of Underwater Robot

DEFF Research Database (Denmark)

Zhao, Bo; Skjetne, Roger; Blanke, Mogens

2014-01-01

A particle filter based robust navigation with fault diagnosis is designed for an underwater robot, where 10 failure modes of sensors and thrusters are considered. The nominal underwater robot and its anomaly are described by a switchingmode hidden Markov model. By extensively running a particle...... filter on the model, the fault diagnosis and robust navigation are achieved. Closed-loop full-scale experimental results show that the proposed method is robust, can diagnose faults effectively, and can provide good state estimation even in cases where multiple faults occur. Comparing with other methods...

The vortex mechanism of suppression of tsunami waves by underwater obstacles

Science.gov (United States)

Boshenyatov, B. V.

2017-12-01

A theoretical model explaining the effect of anomalous suppression of the energy (up to 70%) of tsunami-type waves by thin (compared to the wavelength) underwater obstacles is developed based on the integral laws of conservation of mass and energy fluxes. It is shown that the analytical dependences for the coefficients of reflection and transmission of waves across an underwater obstacle that have been obtained using the theoretical model proposed by the author agree with the results of the experiments and numerical simulation based on the complete Navier-Stokes equations.

Development of underwater YAG laser repair welding robots for tanks

International Nuclear Information System (INIS)

Miwa, Yasuhiro; Satoh, Syuichi; Ito, Kosuke; Kochi, Tsutomu; Kojima, Toshio; Ohwaki, Katsura; Morita, Ichiro

1999-01-01

A remote-controlled repair welding robot which uses YAG laser welding technology in underwater environment was developed. This is an underwater robot technology combined with a laser welding technology. This report will describe the structure and performance of this robot, and the welding test results. The repair welding robot consists of two parts. The one is driving equipment, and the other is welding unit. It can swim in the tank, move around the tank wall, and stay on the welding area. After that it starts YAG laser repair welding. The target of this technology is inner surface repair of some tanks made of austenitic stainless steel, for example RW (Radioactive Waste) tanks. A degradation by General Corrosion and so on might be occurred at inner surface of these tanks in BWR type nuclear power plants. If the damaged area is wide, repair welding works are done. Some workers go into the tank and set up scaffolding after full drainage. In many cases it spends too much time for draining water and repair welding preparation. If the repair welding works can be done in underwater environment, the outage period will be reduced. This is a great advantage. (author)

Event localization in underwater wireless sensor networks using Monitoring Courses

KAUST Repository

Debont, Matthew John Robert

2012-08-01

We propose m-courses (Monitoring Courses), a novel solution to localize events in an underwater wireless sensor network. These networks consists of surface gateways and relay nodes. GPS can localize the position of surface gateways which can then distribute their locations through the network using acoustic modems. Relay nodes are deployed to remain static, but these untethered nodes may drift due to water currents, resulting in disruption of communication links. We develop a novel underwater alarm system using a cyclic graph model. In the event of link failure, a series of alarm packets are broadcast in the network. These alarms are then captured by the underwater m-courses, which can also be used to assure network connectivity and identify node failures. M-courses also allow the network to localize events and identify network issues locally before forwarding results upwards to a Surface Gateway node. This reduces communication overhead and allows for efficient management of nodes in a mobile network. Our results show that m-course routing reduces the number of sends required to report an event to a Surface Gateway by up to 80% when compared to a naïve routing implementation.

Underwater image quality enhancement of sea cucumbers based on improved histogram equalization and wavelet transform

Directory of Open Access Journals (Sweden)

Xi Qiao

2017-09-01

Full Text Available Sea cucumbers usually live in an environment where lighting and visibility are generally not controllable, which cause the underwater image of sea cucumbers to be distorted, blurred, and severely attenuated. Therefore, the valuable information from such an image cannot be fully extracted for further processing. To solve the problems mentioned above and improve the quality of the underwater images of sea cucumbers, pre-processing of a sea cucumber image is attracting increasing interest. This paper presents a new method based on contrast limited adaptive histogram equalization and wavelet transform (CLAHE-WT to enhance the sea cucumber image quality. CLAHE was used to process the underwater image for increasing contrast based on the Rayleigh distribution, and WT was used for de-noising based on a soft threshold. Qualitative analysis indicated that the proposed method exhibited better performance in enhancing the quality and retaining the image details. For quantitative analysis, the test with 120 underwater images showed that for the proposed method, the mean square error (MSE, peak signal to noise ratio (PSNR, and entropy were 49.2098, 13.3909, and 6.6815, respectively. The proposed method outperformed three established methods in enhancing the visual quality of sea cucumber underwater gray image.

The risk of nuclear weapons proliferation

International Nuclear Information System (INIS)

Oelgaard, P.L.

1994-01-01

During the later years the risks of nuclear proliferation have again become a major topic of interest. This is primarily due to the acute problems caused by Iraq, North Korea, and the 3 new states of the former USSR, Ukraine, Kazakhstan and Belarus. Analysis shows that security problems and prestige are the two most important motives, when the risks of proliferation are considered. But motives are not enough. To produce nuclear weapons a number of technological requirements must also be fulfilled. The country must be able to produce almost pure fissile material, i.e. 235 U or 239 Pu. It must also be able to solve a number of metallurgical, explosive, ignition, physics and other problems. These are in particular non-trivial, if a implosion weapon is to be designed. A review is made of the nuclear facilities in a number of the countries which have been suggested as possible future nuclear weapons countries. In particular facilities which can produce almost pure fissile materials, 235 U and 239 Pu, are considered. The possibility of nuclear terrorists have often been discussed in the media. However, it seems very unlikely that even a major terrorist or mafia organization will be able to solve all the weapons design problems, even if they could steal the fissile material. It is finally discussed what can be done to reduce the risk of further nuclear proliferation. Political pressure can be brought to bear on countries outside the NPT to join it, but it can be counter-productive, and sometimes the countries that are able to exert such pressure, are not willing to do so for other political reasons. The problem of countries which are party to the NPT, but which are believed to acquire nuclear weapons capability in violation of the treaty, can be countered by unannounced inspections of non-declared facilities. However, such inspections can only be meaningfully performed if the necessary intelligence is available. (EG)

The proliferation of massive destruction weapons and ballistic missiles

International Nuclear Information System (INIS)

Schmitt, M.

1996-01-01

The author studies the actual situation of nuclear deterrence policies, the possibilities of use chemical weapons as massive destructions weapons for non nuclear governments. The situation of non proliferation of nuclear weapons took a new interest with the disintegration of the communism block, but it seems that only few nuclear matter disappeared towards proliferating countries. The denuclearization of Bielorussia, Ukraine and Kazakhstan makes progress with the START I treaty; China has signed the Non proliferation treaty in 1992, it conducts an export policy in matter of equipment and know-how, towards Iran, Pakistan, North Korea, Saudi Arabia and Syria. In a future of ten years, countries such, Iran, North Korea could catch up with Israel, India and Pakistan among non declared nuclear countries. For chemical weapon, Libya, Iran and Syria could catch up with Iraq. (N.C.)

#TheWeaponizationOfSocialMedia

DEFF Research Database (Denmark)

Nissen, Thomas Elkjer

In today’s conflict environment, transformed by information technology and of who can communicate and how, states, non-state actors, ad hoc activist networks and individuals create effect(s) in and through social network media in support of their objectives. #TheWeaponizationOfSocialMedia develops...... a framework for understanding how social network media shapes global politics and contemporary conflicts by examining their role as a platform for conduction intelligence collection, targeting, cyber-operations, psychological warfare and command and control activities. Through these, the weaponization...... of social media shows both the possibilities and the limitations of social network media in contemporary conflicts and makes a contribution to theorizing and studying contemporary conflicts....

Modelling cavitating flow around underwater missiles

Directory of Open Access Journals (Sweden)

Fabien Petitpas

2011-12-01

Full Text Available The diffuse interface model of Saurel et al. (2008 is used for the computation of compressible cavitating flows around underwater missiles. Such systems use gas injection and natural cavitation to reduce drag effects. Consequently material interfaces appear separating liquid and gas. These interfaces may have a really complex dynamics such that only a few formulations are able to predict their evolution. Contrarily to front tracking or interface reconstruction method the interfaces are computed as diffused numerical zones, that are captured in a routinely manner, as is done usually with gas dynamics solvers for shocks and contact discontinuity. With the present approach, a single set of partial differential equations is solved everywhere, with a single numerical scheme. This leads to very efficient solvers. The algorithm derived in Saurel et al. (2009 is used to compute cavitation pockets around solid bodies. It is first validated against experiments done in cavitation tunnel at CNU. Then it is used to compute flows around high speed underwater systems (Shkval-like missile. Performance data are then computed showing method ability to predict forces acting on the system.

An explanatory model of underwater adaptation

Directory of Open Access Journals (Sweden)

Joaquín Colodro

Full Text Available The underwater environment is an extreme environment that requires a process of human adaptation with specific psychophysiological demands to ensure survival and productive activity. From the standpoint of existing models of intelligence, personality and performance, in this explanatory study we have analyzed the contribution of individual differences in explaining the adaptation of military personnel in a stressful environment. Structural equation analysis was employed to verify a model representing the direct effects of psychological variables on individual adaptation to an adverse environment, and we have been able to confirm, during basic military diving courses, the structural relationships among these variables and their ability to predict a third of the variance of a criterion that has been studied very little to date. In this way, we have confirmed in a sample of professionals (N = 575 the direct relationship of emotional adjustment, conscientiousness and general mental ability with underwater adaptation, as well as the inverse relationship of emotional reactivity. These constructs are the psychological basis for working under water, contributing to an improved adaptation to this environment and promoting risk prevention and safety in diving activities.

Monitoring Coral Growth - the Dichotomy Between Underwater Photogrammetry and Geodetic Control Network

Science.gov (United States)

Neyer, F.; Nocerino, E.; Gruen, A.

2018-05-01

Creating 3-dimensional (3D) models of underwater scenes has become a common approach for monitoring coral reef changes and its structural complexity. Also in underwater archeology, 3D models are often created using underwater optical imagery. In this paper, we focus on the aspect of detecting small changes in the coral reef using a multi-temporal photogrammetric modelling approach, which requires a high quality control network. We show that the quality of a good geodetic network limits the direct change detection, i.e., without any further registration process. As the photogrammetric accuracy is expected to exceed the geodetic network accuracy by at least one order of magnitude, we suggest to do a fine registration based on a number of signalized points. This work is part of the Moorea Island Digital Ecosystem Avatar (IDEA) project that has been initiated in 2013 by a group of international researchers (https://mooreaidea.ethz.ch/).

Behavioural Response Thresholds in New Zealand Crab Megalopae to Ambient Underwater Sound

Science.gov (United States)

Stanley, Jenni A.; Radford, Craig A.; Jeffs, Andrew G.

2011-01-01

A small number of studies have demonstrated that settlement stage decapod crustaceans are able to detect and exhibit swimming, settlement and metamorphosis responses to ambient underwater sound emanating from coastal reefs. However, the intensity of the acoustic cue required to initiate the settlement and metamorphosis response, and therefore the potential range over which this acoustic cue may operate, is not known. The current study determined the behavioural response thresholds of four species of New Zealand brachyuran crab megalopae by exposing them to different intensity levels of broadcast reef sound recorded from their preferred settlement habitat and from an unfavourable settlement habitat. Megalopae of the rocky-reef crab, Leptograpsus variegatus, exhibited the lowest behavioural response threshold (highest sensitivity), with a significant reduction in time to metamorphosis (TTM) when exposed to underwater reef sound with an intensity of 90 dB re 1 µPa and greater (100, 126 and 135 dB re 1 µPa). Megalopae of the mud crab, Austrohelice crassa, which settle in soft sediment habitats, exhibited no response to any of the underwater reef sound levels. All reef associated species exposed to sound levels from an unfavourable settlement habitat showed no significant change in TTM, even at intensities that were similar to their preferred reef sound for which reductions in TTM were observed. These results indicated that megalopae were able to discern and respond selectively to habitat-specific acoustic cues. The settlement and metamorphosis behavioural response thresholds to levels of underwater reef sound determined in the current study of four species of crabs, enables preliminary estimation of the spatial range at which an acoustic settlement cue may be operating, from 5 m to 40 km depending on the species. Overall, these results indicate that underwater sound is likely to play a major role in influencing the spatial patterns of settlement of coastal crab

The Spear: An Effective Weapon Since Antiquity

Directory of Open Access Journals (Sweden)

Robert E. Dohrenwend

2012-07-01

Full Text Available The spear is perhaps man’s oldest weapon, and may even be his oldest tool. Over the hundreds of thousands of years of the weapon’s existence, it evolved from a pointed stick into an efficient hunting missile, and then became the most effective hand-held bladed weapon humans ever devised. The spear and its use is the only martial art originally devised for use against species other than our own, and more than any other weapon, the spear emphasizes the relationship between hunting and warfare. Virtually without exception, the spear is present wherever there are humans. The spear may claim to be the senior martial art, and the weapon is still in use today. Early techniques are preserved by the small number of Japanese sojutsu schools, and modern Chinese martial artists have developed elegant and impressive gymnastic routines for the spear. The javelin throw is a modern Olympic track and field event, and there are people who have resurrected the Aztec atlatl for sporting competition. Today, the spear is still used in Europe for hunting wild boar, and the continued issue of the obsolete bayonet to modern soldiers testifies to a deep, almost instinctive respect still possessed by the military for the spear.

Non-Lethal Weapons Program

Science.gov (United States)

Sheets Frequently Asked Questions Non-Lethal Weapons FAQs Active Denial System FAQs Human Electro -Muscular Incapacitation FAQs Related Links Business Opportunities Contact JNLWD Congressional Engagement , Wednesday, Sept 20, 2017. The Active Denial System, blunt-impact munitions, dazzling lasers, LRAD 100X

Autonomous underwater vehicle for research and rescue operations

CSIR Research Space (South Africa)

Holtzhausen S

2008-11-01

Full Text Available Autonomous under water vehicles are ideal platforms for search and rescue operations. They can also be used for inspection of underwater terrains. These vehicles need to be autonomous and robust to cope with unpredictable current and high pressures...

A Doubly-Curved Piezoelectric Composite with 1-3 Connectivity for Underwater Transducer Applications

Science.gov (United States)

Zhang, Yanjun; Wang, Likun; Qin, Lei; Liao, Qingwei; Zhong, Chao

2018-03-01

Aim to increase the horizontal and vertical beam width of the high frequency transducer simultaneously, we present a doubly-curved 1-3 piezoelectric composite element. It consists of 54% piezoelectric ceramic volume fraction and two phases polymer matrix. The finite element analysis (FEA) is used to evaluate the dynamic response of composite. Electroacoustic response in water was measured for the doubly-curved composite being considered as underwater transducer. An underwater transducer was fabricated using the doubly-curved 1-3 piezoelectric composite element. The -3 dB full angle beam width of transducer is approximately 106° and 36° in the horizontal and vertical plane respectively. Both the FEA simulations and experimental results show the potential of a broad covered area of the composite transducer in underwater environment.