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[CATALÀ] En aquest treball es realitzarà un estudi de viabilitat d’una fresadora de 5 eixos. Primerament es realitzarà un estudi de l’evolució de les fresadores, així es podran localitzar les necessitats actuals del mercat. Tot seguit, ja coneixent el comerç que envolta el món de les fresadores, es procedirà a observar les màquines 5 eixos. De tal manera es podrà veure els diferents tipus de fresadores que es troben al mercat. Seguidament, s’extraurà les prestacions que volen sol·licitar a través de les necessitats extretes. A continuació, s’aprofundirà en un estudi més precís on s’analitzarà els diversos elements i condicions que es requereixen per tal de fer efectiva la fresadora que es vol extreure al mercat. Així, s’explicarà clarament les característiques i els diferents elements que la formen. Un cop ja s’ha fet l’estudi, ja hi haurà una primera idea. Tot seguit, es procedirà a fer l’estudi més precís on s’observarà les especificacions de la màquina, tots els sistemes que l’envolten i la normativa que s’ha aplicat per tal de fer efectiva la seva sortida al comerç, Un cop es té clar les seves especificacions es podrà saber quins elements i necessitats es tindran per tal de poder extreure la màquina des de 0. Per aquest motiu es procedirà a crear el seu pressupost, i dins d’aquest estudi de mercat es compararà amb la competència per veure si es viable crear la fresadora i si té futur. Per acabar el treball, s’explicarà el manteniment que volta les fresadores de 5 eixos per tal de donar-li un punt de valor, ja que ha estat dissenyada per a la reducció del cost de manteniment i per l’estalvi en procediment de càrrega d’aquesta. Es tindrà en compte tots aquells detalls per tal de facilitar el treball del tècnic., [ANGLÈS] In this final degree project, a feasibility study of a 5-axis milling machine will be made. First of all, will take a look to its evolution, so we could observe the needs at this moment in the market. Then, once we know about the milling machine's market we will proceed to analyze the 5-axis milling machines, that way we can observe the different types of milling machines there are. We will then extract the benefits that they want to request through the needs extracted from the market. Then we will go deeper into a more precise study where we will observe the different elements and necessary conditions, in order to make effective the milling machine that it wants to be extract. Thus, the characteristics and the different elements that make up the machine will be clearly explained. With the study done there is already a first idea of the machine in question. The specifications of the machine will also be duly analyzed, where we will see a study of all the systems that surround it and the regulations applied to make its exit to the market effective. Once this is done, it will be clear what elements and needs will be considered in order to extract the machine from scratch. For this reason we will create a budget and observing the market study with the competition, it will be looked at if it is feasible to create the milling machine, and if it has a future in this market. To finish the work, we will describe the maintenance that surrounds the machine in order to give it a point of value since it has been designed for the reduction of the cost of maintenance and for the saving in procedure of load of this machine, since details will be taken into account in order to facilitate the work of the technician.

Humans have altered the ocean on a global scale. From large-scale extractive activities such as fishing, to the unintentional introduction and spread of invasive species via shipping vessels, human activities shape marine communities worldwide, having myriad effects on ecosystem functions and resilience. Even recreational activities that are assumed to have lesser impacts, such as SCUBA diving, are intensifying and becoming increasingly concentrated inside marine protected areas. Research into a wide range of direct and obvious human impacts has informed the effective management of marine systems for both conservation goals and human uses. However, understanding the more nuanced pathways for the effects of human disturbance is critical, especially in systems facing multiple stressors, as they may serve to tip the balance between healthy ecosystems and degraded ones. In particular, there is recent and growing evidence that human activities are altering predation risk in marine systems. When humans change the abundance, distribution, or behavior of marine predators, whether through fishing or other forms of disturbance, those changes can ripple through marine ecosystems due to the comparatively large effects that predators have on other trophic levels. Predators exert both consumptive and non-consumptive effects on prey populations, and can thus influence other species interactions and trigger cascades that can result in the fundamental restructuring of marine systems. However, although risk effects have been well studied in terrestrial systems, these effects have been largely neglected in marine systems. In this thesis, I explore two different pathways for the effects of human alteration of predation risk. My first two chapters examine the non-consumptive, or fear effects of recreational spearfishing, diving, and snorkeling to marine fish. My third chapter examines the consumptive effects of an introduced predator on both a native and an invasive prey population, and

Humans have altered the ocean on a global scale. From large-scale extractive activities such as fishing, to the unintentional introduction and spread of invasive species via shipping vessels, human activities shape marine communities worldwide, having myriad effects on ecosystem functions and resilience. Even recreational activities that are assumed to have lesser impacts, such as SCUBA diving, are intensifying and becoming increasingly concentrated inside marine protected areas. Research into a wide range of direct and obvious human impacts has informed the effective management of marine systems for both conservation goals and human uses. However, understanding the more nuanced pathways for the effects of human disturbance is critical, especially in systems facing multiple stressors, as they may serve to tip the balance between healthy ecosystems and degraded ones. In particular, there is recent and growing evidence that human activities are altering predation risk in marine systems. When humans change the abundance, distribution, or behavior of marine predators, whether through fishing or other forms of disturbance, those changes can ripple through marine ecosystems due to the comparatively large effects that predators have on other trophic levels. Predators exert both consumptive and non-consumptive effects on prey populations, and can thus influence other species interactions and trigger cascades that can result in the fundamental restructuring of marine systems. However, although risk effects have been well studied in terrestrial systems, these effects have been largely neglected in marine systems. In this thesis, I explore two different pathways for the effects of human alteration of predation risk. My first two chapters examine the non-consumptive, or fear effects of recreational spearfishing, diving, and snorkeling to marine fish. My third chapter examines the consumptive effects of an introduced predator on both a native and an invasive prey population, and

Sea nomads or 'sea people,' namely the 'Bajau Laut' in the Philippines, Malaysia and Indonesia are skilled divers, and many Bajau Laut make a living from freediving. Men do most of the spearfishing, but women also dive, predominantly for gathering sea food. They start to dive at an early age and spend most days of their lives on and in the sea. Our objective was to study their diving and way of life, to reveal if modern humans have the physiological potential for making a living from breath-hold diving for fishing and gathering. Bajau Laut were visited for a total of nine months, during three periods from 2010-2013, in a combined physiological and social-Anthropological study. The diving physiology studies focused on a total of 10 male divers, whose working day diving while spearfishing was logged with time-depth loggers. One group of 5 divers were engaged in shallow (5-7 m) spearfishing with an underwater working time of 60%, when diving for 2-9 h. The other group of 5 divers went to a mean depth of 10 m and had an underwater working time of 50%, when diving for 3-9 h per day. During that time, between one and eight kilograms of coral fish, blow fish, moray eels and octopuses were caught, per diver. Seafood collected by the women included clams, crustaceans, sea weed and sea cucumbers. Life among the Bajau Laut was much like it was 25 years ago, although in some areas the fish stock is diminishing, making it necessary for the Bajau Laut to spend more time in the water to obtain the same quantity of fish. It was concluded that modern humans do possess the physiological qualities necessary for making a living from hunting-gathering via breath-hold diving.

Sea nomads or 'sea people,' namely the 'Bajau Laut' in the Philippines, Malaysia and Indonesia are skilled divers, and many Bajau Laut make a living from freediving. Men do most of the spearfishing, but women also dive, predominantly for gathering sea food. They start to dive at an early age and spend most days of their lives on and in the sea. Our objective was to study their diving and way of life, to reveal if modern humans have the physiological potential for making a living from breath-hold diving for fishing and gathering. Bajau Laut were visited for a total of nine months, during three periods from 2010-2013, in a combined physiological and social-Anthropological study. The diving physiology studies focused on a total of 10 male divers, whose working day diving while spearfishing was logged with time-depth loggers. One group of 5 divers were engaged in shallow (5-7 m) spearfishing with an underwater working time of 60%, when diving for 2-9 h. The other group of 5 divers went to a mean depth of 10 m and had an underwater working time of 50%, when diving for 3-9 h per day. During that time, between one and eight kilograms of coral fish, blow fish, moray eels and octopuses were caught, per diver. Seafood collected by the women included clams, crustaceans, sea weed and sea cucumbers. Life among the Bajau Laut was much like it was 25 years ago, although in some areas the fish stock is diminishing, making it necessary for the Bajau Laut to spend more time in the water to obtain the same quantity of fish. It was concluded that modern humans do possess the physiological qualities necessary for making a living from hunting-gathering via breath-hold diving.

Sea nomads or 'sea people,' namely the 'Bajau Laut' in the Philippines, Malaysia and Indonesia are skilled divers, and many Bajau Laut make a living from freediving. Men do most of the spearfishing, but women also dive, predominantly for gathering sea food. They start to dive at an early age and spend most days of their lives on and in the sea. Our objective was to study their diving and way of life, to reveal if modern humans have the physiological potential for making a living from breath-hold diving for fishing and gathering. Bajau Laut were visited for a total of nine months, during three periods from 2010-2013, in a combined physiological and social-Anthropological study. The diving physiology studies focused on a total of 10 male divers, whose working day diving while spearfishing was logged with time-depth loggers. One group of 5 divers were engaged in shallow (5-7 m) spearfishing with an underwater working time of 60%, when diving for 2-9 h. The other group of 5 divers went to a mean depth of 10 m and had an underwater working time of 50%, when diving for 3-9 h per day. During that time, between one and eight kilograms of coral fish, blow fish, moray eels and octopuses were caught, per diver. Seafood collected by the women included clams, crustaceans, sea weed and sea cucumbers. Life among the Bajau Laut was much like it was 25 years ago, although in some areas the fish stock is diminishing, making it necessary for the Bajau Laut to spend more time in the water to obtain the same quantity of fish. It was concluded that modern humans do possess the physiological qualities necessary for making a living from hunting-gathering via breath-hold diving.

Sea nomads or 'sea people,' namely the 'Bajau Laut' in the Philippines, Malaysia and Indonesia are skilled divers, and many Bajau Laut make a living from freediving. Men do most of the spearfishing, but women also dive, predominantly for gathering sea food. They start to dive at an early age and spend most days of their lives on and in the sea. Our objective was to study their diving and way of life, to reveal if modern humans have the physiological potential for making a living from breath-hold diving for fishing and gathering. Bajau Laut were visited for a total of nine months, during three periods from 2010-2013, in a combined physiological and social-Anthropological study. The diving physiology studies focused on a total of 10 male divers, whose working day diving while spearfishing was logged with time-depth loggers. One group of 5 divers were engaged in shallow (5-7 m) spearfishing with an underwater working time of 60%, when diving for 2-9 h. The other group of 5 divers went to a mean depth of 10 m and had an underwater working time of 50%, when diving for 3-9 h per day. During that time, between one and eight kilograms of coral fish, blow fish, moray eels and octopuses were caught, per diver. Seafood collected by the women included clams, crustaceans, sea weed and sea cucumbers. Life among the Bajau Laut was much like it was 25 years ago, although in some areas the fish stock is diminishing, making it necessary for the Bajau Laut to spend more time in the water to obtain the same quantity of fish. It was concluded that modern humans do possess the physiological qualities necessary for making a living from hunting-gathering via breath-hold diving.

Sea nomads or 'sea people,' namely the 'Bajau Laut' in the Philippines, Malaysia and Indonesia are skilled divers, and many Bajau Laut make a living from freediving. Men do most of the spearfishing, but women also dive, predominantly for gathering sea food. They start to dive at an early age and spend most days of their lives on and in the sea. Our objective was to study their diving and way of life, to reveal if modern humans have the physiological potential for making a living from breath-hold diving for fishing and gathering. Bajau Laut were visited for a total of nine months, during three periods from 2010-2013, in a combined physiological and social-Anthropological study. The diving physiology studies focused on a total of 10 male divers, whose working day diving while spearfishing was logged with time-depth loggers. One group of 5 divers were engaged in shallow (5-7 m) spearfishing with an underwater working time of 60%, when diving for 2-9 h. The other group of 5 divers went to a mean depth of 10 m and had an underwater working time of 50%, when diving for 3-9 h per day. During that time, between one and eight kilograms of coral fish, blow fish, moray eels and octopuses were caught, per diver. Seafood collected by the women included clams, crustaceans, sea weed and sea cucumbers. Life among the Bajau Laut was much like it was 25 years ago, although in some areas the fish stock is diminishing, making it necessary for the Bajau Laut to spend more time in the water to obtain the same quantity of fish. It was concluded that modern humans do possess the physiological qualities necessary for making a living from hunting-gathering via breath-hold diving.

A novel application for Autonomous Underwater Vehicles (AUVs) is considered here: a robotic diver assistant that enables close-quarters robotic operations with human divers. A robotic diver assistant has the potential to improve the efficiency, effectiveness and safety of diver operations. The robot diver assistant must share the operating environment with human divers, navigate relative to the environment to reach a specified site location (along with moving divers), and then maneuver among the mostly static divers as they perform their tasks on location. The robot operates in three unique scenarios: station-keeping, diver-following (shadowing), and diver-leading (vectoring). Various strategies for navigating among divers while ensuring diver safety are investigated. A reactive strategy, based on potential fields, is investigated and applied to station-keeping and diver-following. A deliberative approach, which plans the robot s motion over a finite horizon, is presented for diver leading. These approaches are applied to the SeaBotix vLBV300 platform for which a simulator is developed based on a decoupled motion model for the platform, as well as experimental results in a controlled test tank.

Inner ear decompression sickness (DCS) has followed deep breathing gas switches to air (or other nitrogen-oxygen mixtures) during decompression from deep heliox dives. This study investigates the safety of heliox-to-air breathing gas switches at moderate depths. Divers immersed in 80 F (27 C) water were compressed to 150, 170, or 190 fsw (561, 622, 683 kPa) breathing 79% helium-21% oxygen or to 220 fsw (775 kPa) breathing 84% helium-16% oxygen for a 60-minute bottom time- a time estimated to allow 99% equilibration of inner ear gas tensions with breathing gas. Divers were then decompressed at 30 fsw/min to 70 fsw (316 kPa) from 150 fsw, or to 100 fsw (408kPa) from the other depths. At 70 or 100 fsw, divers exited the water and breathed chamber air for 60 minutes. Following this air stop, divers were decompressed breathing 50% nitrogen-50% oxygen and 100% oxygen. Profiles were tested in order of increasing maximum depth. Each profile was accepted if 25 man-dives were free from inner ear or other central nervous system DCS during the air stop- a design chosen to detect greater than 0.2% probability of central nervous system DCS with approximately 3% significance and 96% power. There was no diagnosed DCS during or following any of the 104 man-dives completed. On the 220 fsw dive profile, one diver complained of fullness in the ear at the air stop that resolved during subsequent decompression and one diver complained of fleeting, mild shoulder pain (niggles) during decompression from 100 fsw. Equilibration of the inner ear with 651 kPa inspired helium followed by no-stop decompression to 100 fsw and switch to air breathing appears to have a low risk of inner ear DCS., The original document contains color images.

The Navy s Dive and Salvage community is in need of a new dive stage, called the SMART Stage, which will increase the productivity and safety of its users along with matching their capabilities to that of the commercial industry. The existing dive stage is a stainless steel cage that merely transports divers and their tools from the surface towards the worksite at a maximum depth of 300 feet. What modifications and improvements can be made to make the divers safe? Improve productivity? Should this new stage be comprised of commercial off-the-shelf parts or can it be purchased as a pre-fabricated system? This thesis will investigate what is needed to improve the safety and productivity for the community as well as the possible design alternatives of a SMART Stage. This study will perform the Systems Engineering process by carrying out a stakeholder needs analysis to help define the functions and requirements that must be met by the SMART Stage.

Är dykare spänningssökare? Är män mer spänningssökande än kvinnor? 51 dykare, 27 män och 24 kvinnor, läts fylla i enkäten Sensation seeking scale version 5 (SSS-V). Sensation seeking scale har utvecklats av Marvin Zuckerman med kollegor sedan 1960-talet och mäter graden av spänningssökande personlighetsdrag, på engelska: sensation seeking. Enkäten har visat sig valid på flera hundra studier men har bara testats på dykare ett fåtal gånger. Hypoteserna är att dykare är mer spänningssökande än normalpopulationen (H1) och att dykande män är mer spänningssökande än dykande kvinnor (H2). Kontrollgruppen består av psykologistudenter från Delware University mellan år 1986 och 1992, 410 män och 807 kvinnor. Resultatet visar med statistisk signifikant säkerhet att dykare är mer spänningssökande än normalpopulationen och att dykande män är mer spänningssökande än dykande kvinnor. Validitet och alternativ till Sensation seeking scale m.m. tas upp i diskussionsdelen.

Är dykare spänningssökare? Är män mer spänningssökande än kvinnor? 51 dykare, 27 män och 24 kvinnor, läts fylla i enkäten Sensation seeking scale version 5 (SSS-V). Sensation seeking scale har utvecklats av Marvin Zuckerman med kollegor sedan 1960-talet och mäter graden av spänningssökande personlighetsdrag, på engelska: sensation seeking. Enkäten har visat sig valid på flera hundra studier men har bara testats på dykare ett fåtal gånger. Hypoteserna är att dykare är mer spänningssökande än normalpopulationen (H1) och att dykande män är mer spänningssökande än dykande kvinnor (H2). Kontrollgruppen består av psykologistudenter från Delware University mellan år 1986 och 1992, 410 män och 807 kvinnor. Resultatet visar med statistisk signifikant säkerhet att dykare är mer spänningssökande än normalpopulationen och att dykande män är mer spänningssökande än dykande kvinnor. Validitet och alternativ till Sensation seeking scale m.m. tas upp i diskussionsdelen.

The United States Marine Corps' ability to meet the requirements of the DOD that broaden littoral maneuver and amphibious operations capabilities requires the effective. Discussion: With current reduction of forces in support of Operation Enduring Freedom-Afghanistan, the contemporary operational environment is moving toward hybrid warfare. The United States Marine Corps needs a world class Force Reconnaissance capability. The level of commitment required includes a rigorous selection process, specialized equipment for special insertion and extraction skills, the ability to build capability, and financial resources. The ability to operate in a dynamic, ambiguous environment that requires various capabilities in order to acquire information to provide a commander with strategic and operational level decision making is even more demanding. The analysis of the historical origins and evolution of Force Reconnaissance from World War II to Operations Enduring Freedom-Afghanistan and beyond requires a major shift in operational employment toward a future operational environment. This study identifies the current capabilities of Force Reconnaissance to support the Marine Air Ground Task Force and the ability to provide access, mobility and deep strike capable units in future operational employment. In order to support the future of the United States Marine Corps, Force Reconnaissance's way ahead must be based upon an integrated intelligence & operations, dedicated enabler packages, and a habitual relationship with air assets. The United States Marine Corps will need to prioritize its Force Reconnaissance capability to ensure it is properly manned, trained, and equipped for future threats.

This study was conducted in response to a Support to Operations/Support to Development Engineering and Evaluation (STO/DEE) request from ADM (Mat) for information relating to Canadian Forces divers' risk of developing noise-induced hearing loss during simulated dives. During a simulated dive, high pressure air is transferred into the dive chamber of a hyperbaric facility. The mechanism is audible and sufficiently high in level in adjacent areas to warrant the use of hearing protection. There were two parts to the experiment, the assessment of hearing protector attenuation and the measurement of sound levels. In Part I, hearing thresholds were measured at frequencies from 250-8000 Hz in twenty normal-hearing males and females (1) with the head uncovered and ears unoccluded, (2) while wearing a wetsuit hood, and (3) while fitted with three hearing protection earmuffs, unvented and vented. Venting, the practice of drilling a small hole in earcups, is meant to prevent eardrum barotrauma. Attenuation was derived by subtracting the unoccluded from the protected thresholds. In Part II, sound level measurements were made at twenty-two positions within the Diving Research and Diving Training Facilities of Defence Research and Development Canada ? Toronto. Earmuff venting resulted in a decrease in attenuation of as much as 17 dB at 250 Hz and 500 Hz. Although it was determined that some of the protected sound levels might be unsafe, the exposure duration was sufficiently short to minimize the possibility of hearing damage.

Canada currently possesses limited to modest Mine Counter Measure (MCM) capability that includes Maritime Coastal Defence Vessels (MCDVs) used for coastal surveillance and patrol, and Clearance Diving Units for identification and disposal of sea mines. In recognition of its MCM capability deficiencies, Canada has been actively involved in defining a program for integrating unmanned underwater vehicles (UUVs) in current MCM operations through collaboration with other Allied nations. In line with this effort, the Underwater Intervention in Shallow Water/Very Shallow Water (SW/VSW) Operations Applied Research Project (ARP) was proposed in 2008 with the objective to improve Canadian Forces' (CF) capability to conduct MCM, combat diving, and Special Operations Force operations in shallow and very shallow water by increasing the capacity of underwater systems, operators, and divers; reducing risk and equipment burden on the diver; and extending speed and accuracy in the conduct of these operations. The NATO certification Exercise NOBLE MARINER 11 was identified as a suitable venue for exposing CF personnel and Defence Research and Development Canada-Toronto (DRDC) analysts to MCM operations and enabling them to gain a more holistic understanding of the MCM process. The team's experiences from various ships were consolidated into a comprehensive list of deficiencies in the following areas: (1) sonar operators, (2) diving operations, (3) unmanned underwater vehicles, (4) underwater communications, (5) C2 communications, and (6) planning and risk calculation software. This report summarizes these deficiencies as observed by the CF and DRDC researchers during the exercise, and proposes areas for future research for the above ARP. The insights gained from this analysis will be used to provide Canada and its allies with adaptive and easy-to-interpret feedback on their operational practices and plans as they conduct MCM operations., Text in English; abstract and executive summary in English and French.

Robust communications are key to the success of naval operations such as area surveillance, control, and interdiction. Communications and sensor networks allow the flow of data and critical information that are necessary for conducting such operations from both tactical and strategic perspectives. In naval operations, platforms are hardly stationary, as the networking infrastructure operates from a variety of platforms in motion on the sea, above the sea, and from space. Sensor networks consist of nodes made up of small sensors that are able to monitor, process, and analyze phenomena over geographical regions of varying size and for significant periods. Some categories of these small sensors are able to collect and transmit sensor data about physical values (e.g., temperature, humidity, and sea state), or dynamic attributes of objects, such as speed, direction, and the existence of dangerous substances (e.g., radioactive materials and explosives). The objective of this thesis is to examine how unstructured sensor networks, known as ad-hoc sensor networks, can effectively support maritime interdiction operations and regional security by providing reliable communications and flow of information.

After a records search identified men and women who, on active duty between 1960 and 1990, had served as U.S. Navy divers performing saturation, experimental, or both saturation and experimental dives, their current health status was surveyed. During that period, others from the fleet diver population whom the search did not identify as having performed either saturation or experimental dives served as a fourth group, a reference comparison group. When all the divers (n=5,422) were mailed invitations to participate, 33% (n=1,792) agreed to complete a self-report survey requesting information on their lifestyle behaviors, occupational histories, diving exposures, and the statuses of their current health, physical activity, and cognitive functioning. The final participation rate (surveys used / mailed invitations) was 27.5%. From this study group of enlisted (60%), warrant officer (5%), and commissioned officer (35%) personnel, the surveys of 1,475 male and 15 female divers (92% military retirees and 8% active duty members) were analyzed. These divers served an average of 24 active duty years, with an average of 18 years of active duty diving. Their average age was 56. Married divers represented 87% of the participants; divorced or widowed, 11%; and never married, 1%. Of all these divers, 60% now receive disability compensation. One in five divers had experienced pain-only decompression sickness (DCS); one in seven, neurological DCS. One in four said that, within 24 hours of a dive, they had suffered pain or neurological symptoms for which they had not sought treatment; symptoms had failed to resolve for 6% of these divers. Overall, 41% of the divers had experienced one or more of nine dive-related injuries. Fifty-four percent of the divers had reported a lost-time (longer than three days) accident at work, and 62% had been deployed to a theater of combat operations., The original document contains color images.

The USN N2-O2 primary data set is a collection of dive profiles that the U.S. Navy uses to calibrate probabilistic decompression models for air and N2-O2 diving. Each dive profile describes the depth/time/breathing gas history,number of participating divers, and decompression outcome of experimental dives. Original research reports, research protocols, databases, and diving logs describing the experimental dives were searched for work and temperature information. A subset of the USN N2-O2 primary data set was augmented so that dive profiles included diver whole body oxygen consumption (estimated from descriptions of work performed), work type, posture, water temperature, and diving dress. Two additional data files describing experimental dives that compared working and resting dives were also augmented

Classical decompression algorithms limit hypothetical tissue gas contents and prescribe decompression schedules with most of the total stop time (TST) allocated to shallow decompression stops. More recent bubble-model-based algorithms limit hypothetical bubble profusion and size and prescribe decompressions with TST skewed toward deeper stops. A large man-trial compared the efficiency of these approaches. Divers wearing swimsuits and tshirts breathing surface-supplied air via MK 20 UBA, and immersed in 86 ?F water were compressed at 57 fsw/min to 170 fsw for a 30 minute bottom time during which they performed 130 watt cycle ergometer work. They were then decompressed at 30 fsw/min with stops prescribed by one of two schedules. The shallow stops schedule, with a first stop at 40 fsw and 174 minutes TST, was prescribed by the, deterministic, gas content, VVAL18 Thalmann Algorithm. The deep stops schedule, with a first stop at 70 fsw, was the optimum distribution of 174 minutes TST according to the probabilistic BVM(3) bubble model. Decompression sickness (DCS) incidence following these schedules was compared. The trial was terminated after the midpoint interim analysis, when the DCS incidence of the deep stops dive profile (11 DCS/198 dives) was significantly higher than that of the shallow stops dive profile (3/192, p=0.030, one-sided Fisher Exact). On review, one deep stops DCS was excluded, but the result remained significant (p=0.047). Most DCS was mild, late onset, Type I, but two cases involved rapidly progressing CNS manifestations. Results indicate that slower tissue gas washout or continued gas uptake offsets the benefits of reduced bubble growth at deep stops.

Swimming-induced pulmonary edema (SIPE) case criteria surveys were distributed to Naval Diving and Salvage Training Center (NDSTC) and Basic Underwater Demolition/SEAL training center (BUD/S). 42 surveys were collected (41 from BUD/S and one from NDSTC). There were approximately 914 NDSTC enrollees and 1440 enrollees at BUD/S. Combining these numbers yields a cumulative cohort of 2354 enrollees. Two of the completed surveys were positive for all five case criteria yielding a 0.085% incidence of SIPE from March 2010 through April 2011 at the two Navy dive training facilities. Considering all completed surveys as cases of SIPE, the incidence increases to 1.78%. There was no correlation between return to duty time, water temperature, activity in the water or number of case criteria positive for SIPE. SIPE remains a potential cause of morbidity and lost training time amongst diving trainees. With proper identification and supportive care, it resolves relatively quickly. Compared to the reported incidence of common musculoskeletal training injuries, the incidence of SIPE at Navy dive training facilities is lower. SIPE is more commonly diagnosed at BUD/S compared to the NDSTC., The original document contains color images.

In 2004 Navy Experimental Diving Unit was tasked to prototype a dive data collection and management system. As a topside decompression monitor (TDM), the system must be able to operate at remote diving locations and provide dive supervisors and operators with real-time dive decompression information. The TDM will collect diver depth and temperature information and update this into its TDM topside computer, which has been programmed to provide real-time decompression schedules for the diver(s). TDM hardware components include a laptop computer, instrumentation case, diver instrumentation cable, and diver-worn depth sensor; its software components include a decompression program and a data management program. Special permission is currently obtained to actively use the TDM in an ongoing diving operation. The TDM monitors diver depth, computes real-time decompression profiles,and provides information to dive supervisors and operators, so that they can act to ensure the safety of the divers. The TDM is in the field and is being received in a positive manner by dive supervisors and operators using the system., Report contains color.

US Army Engineer District - Chicago operates an electric field-based aquatic nuisance species dispersal barrier system in the Chicago Sanitary and Ship Canal (CSSC), Romeoville, IL. The barriers were constructed to prevent the movement of invasive species, such as Asian big-head carp (Hypophthalmichthys nobilis) and silver carp (Hypophthalmichthys molitrix) between the Mississippi River and Great Lakes basins. The objective of this project was to perform a series of in-water tests on the barrier addressing field-strength mapping, sparking potential during barge fleeting and collision, voltage potentials between barges traversing the barriers, personnel in-water shock potential, stray-current corrosion potential, and optimal settings for the parasitic barrier system. Test results and analysis indicate there is no significant risk of personnel shock hazard in the fleeting area during barrier operations for any operating configuration. Also, while some operational scenarios were found to increase sparking risk if barges collide with each other or separate metal objects, analysis indicates that concerns about coal dust explosion hazard from sparking are not supported by the technical literature. A detailed set of data, analysis, conclusions, and recommendations is provided in the report text and four appendices., Project title: CSSC Dispersal Barrier II, ERDC-CERL Safety Studies . The original document contains color images.

Divers operate in a hostile environment that is physically stressful and mentally demanding. They must also function autonomously as communications are very limited during the dive. Each diver must be responsible for his her own safety, as well as accomplishment of mission objectives. For some time, dive computers have been used to monitor dive profiles (depth and dive duration) and equipment (tank pressure and gas mixture). However, divers have no tools for monitoring the most critical determinant of their safety and effectiveness - their body. The goal of this project is development of a Diver Health Monitoring System (DHMS). The DHMS will provide the Navy with a powerful capability for real-time monitoring of the electrocardiogram and other key physiological parameters during diving. The system evolves the concept of the current dive computer into a physiological monitor capable of measuring the diver's critical vital signs and ultimately predict impending problems (e.g.. hypothermia and excessive fatigue)., Prepared in cooperation with the Center for Research and Education in Special Environments (CRESE), State University of New York (SUNY) at Buffalo and Vermed Incorporated, Bellows Falls, VT.

This manual describes the features and functionality of the Creare Diver Health Monitoring System (DHMS). The Creare DHMS is a body-worn sensor system for monitoring a diver's physiologic condition, as well as of his environment. Currently, the DHMS consists of a single body-worn sensor that measures the divers electrocardiogram (ECG). The DHMS sensor records the ECG and determines the diver's current heart rate. The device logs the data for later retrieval and it also broadcasts the data in real time over a wireless link to a nearby computer. The use of the DHMS system is aimed at researchers performing experiments on divers. The system can be used wet or dry, at the surface or at depth. The DHMS is composed of three components: (1) one or more body-worn sensors. (2) a general purpose PC running a custom-written application to control the sensors and to receive the data, and (3) a dock for recharging the body-worn sensors., See also ADA550401, Diver Health Monitoring System. Prepared in cooperation with the Center for Research and Education in Special Environments (CRESE), State University of New York (SUNY) at Buffalo and Vermed Incorporated, Bellows Falls, VT. Creare Project 8452.

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This Coastal and Hydraulics Engineering Technical Note (CHETN) describes the initial results of an investigation to determine the feasibility of using acoustical imaging for underwater inspection of structures. Visibility in clear water for the human eye and optical systems such as video cameras extends to about 15 m with appropriate lighting. However, the lack of visibility caused by the presence of suspended material in some rivers and impoundments presents many mission problems for personnel of the U.S. Army Corps of Engineers. Typical situations in which lack of visibility causes problems include assessing conditions of underwater structures such as gates and concrete piers, which are Operation and Maintenance issues; positioning of float-in structures, a construction issue; the investigation of archeological sites; and detection of endangered species. Currently, condition assessments typically involve the use of divers to inspect and record the condition of underwater structural components. This is expensive and often poses the risk of personal injury to the divers. Ultrasonic imaging system technology originally developed for the medical field helps provide potential solutions to the problems of poor visibility in turbid water. The U.S. Army Engineer Research and Development Center (ERDC) in Vicksburg purchased an acoustical camera to evaluate and further develop its capability as a tool to aid in the inspection of structures in turbid water.

Cognitive effects of inspired doses of CO2 during submerged working dives have previously not been explored. Three experiments using male volunteer Navy divers in the NEDU test pool under 12 feet of fresh water explored: (1) dose-related and on/off effects of 1.5% (Phase 1a, N=20) and 3% (Phase 1b, N=16) inspired CO2; (2) questions of whether switching to gas free of CO2 results in further changes in performance or restoration to baseline (Phase 2, N=34); and (3) differences in the effects of CO2 in air vice in O2 (Phase 3, N=16). End tidal CO2 was collected from all divers and correlated with cognitive performance. The Automated Neuropsychological Assessment Metrics, version 4 (ANAM4), was used before and four times during each dive ? with three intermittent periods of mild or moderate exercise during each dive ? to measure nine cognitive domains. No dose-related effect of CO2 was found. Basic cognitive domains of simple reaction time, visual scanning, visuo-spatial processing, and learning were unaffected, while fatigue and the higher cognitive functions of short-term memory (STM), long-term memory (LTM), working memory (WM), math processing, and sustained attention produced perplexing results. Most consistent of all differences was the decrease in LTM while divers were on CO2, a decrease that persisted in Phase 1 even after divers were removed from CO2 and returned to O2. Math processing, WM, and sustained attention increased among divers both during and after breathing CO2. STM decreased on CO2 in Phase 1 but not in Phase 2. No cognitive changes were detected on air, when end tidal CO2 remained closer to normal than on O2. While some participants reported mild to moderate symptoms (e.g., headache, shortness of breath, irritability, and lack of concentration), end tidal CO2 levels were mostly 7% Surface Equivalent Value (SEV). Because subjects were not hypercapnic, we cannot address the question of the study. Further investigation of the effects of inspired CO2, The original document contains color images.

This report summarizes the results for five preselected commercially available open circuit scuba regulator models that were tested to determine their suitability for U. S. Navy diving. Five units of each model regulator were tested in both cold (38 deg F) and freezing (29 deg F) water. To emulate the ventilation of a diver, a breathing simulator with a sinusoidal breathing pattern was used, and the exhaled gas was heated and humidified. Freeze-up testing was conducted in freezing water, at a ventilation rate of 62.5 liters per minute (L/min) to a depth of 198 feet of seawater (fsw). To assess the resistive effort at various ventilation rate and volume combinations ranging from 22.5 to 90 L/min, resistive effort tests were performed in cold water from the surface to 198 fsw, with stops made every 33 fsw,. Two regulator models are recommended for use in freezing water.

This is a retrospective case control study comparing decompression sickness (DCS) risk in experimental Navy divers with a patent foramen ovale/right-to-left shunt (PFO/RLS) and in age-matched experimental Navy divers without a PFO/RLS. Eighty-eight subjects completed 432 man-dives in an empirical evaluation of extensions to air diving no-stop limits at Navy Experimental Diving Unit. Six subjects experienced neurologic DCS. Review of transthoracic echocardiography and transcranial Doppler imaging discovered a PFO/RLS in five of those subjects who experienced DCS and in six of 24 divers who had no DCS and had been recruited from the 82 remaining divers participating in the evaluation of the air diving no-stop limits. Logistic regression analysis indicates that after completing selected experimental no-stop dives to at least 150 feet of seawater with bottom times extended beyond current Navy diving limits, divers with a PFO/RLS are at increased risk for DCS.

The MBS 2000 is an O2 rebreather intended for O2 decompression use in a dry chamber. Users purge the breathing loop with O2 at preset intervals. An O2 monitoring system (OMS) may reduce the purging needs or indicate needs for more frequent purging. The OMS for the MBS 2000 consists of a sensor (R10-DN) for partial pressure of O2, but a decision on the need to purge is based on fraction of O2. Since the water vapor content may be more than 10%, the water vapor present must be considered when conversions are made. An R10-DN is sensitive to temperature and is likely to be somewhat nonlinear at the high partial pressures of O2 expected. The OMS indicates a sufficient O2 level by a green light; a red light indicates that purging is needed (switchover at 85%). Manned dives to verify all the functions were required. Twelve military divers participated in the Institutional Review Board?approved manned test of the OMS. Tests lasted 60 minutes at 60 feet of seawater (fsw) and then 60 min at 30 fsw. OMS readings were compared to those of a laboratory-quality O2 analyzer. Compensations for temperature sensitivity and nonlinearity were made for each R10-DN. Oceaneering (Hanover, MD) and Dive Lab (Panama City Beach, FL) delivered the OMS parts. The average number of purges was 6.2 (range 0?14) in the first 30 min, a level dropping to an average of 2.7 (range 0?5) in the second 30 min period at 60 fsw. At the 30 fsw stop the average was 2.5 (range 0?4.5) purges per 30 min. Data on O2 from 10 test divers were used. Differences in readings of the OMS and the Rosemont were calculated for each test diver, and the average was ?0.01% (range +3.2 to?1.7%). The current purge procedure will not notify users who have a stable inspired O2 level between 85 and 90%. Adding a time limit will be sufficient. The MBS 2000 OMS worked well, and its readings compared well with those of the O2 analyzer.

The Thalmann Exponential-Linear Decompression Algorithm (EL-DCA) was developed with the VVal-18 and HVal-21 parameter sets at Navy Experimental Diving Unit (NEDU) to produce 0.7 atmospheres absolute (ata) constant PO2-in-N2 and 0.7 ata constant PO2-in-He decompression tables. The original EL-DCA was extensively modified at NEDU to develop MK 16 MOD 1 N2-O2 and He-O2 decompression tables and Submarine Rescue and Diving Recompression System Operator/Tender decompression tables. The EL-DCA was further modified and used with a modified VVal-18 parameter set, designated VVal-18M, to produce an integrated set of air diving decompression tables for Revision 6 of the U.S. Navy Diving Manual. This report describes the design of the EL-DCA software that was used to produce the integrated air decompression tables and documents the software modifications made since publication of Thalmann's original reports.

The Canadian Underwater Minecountermeasures (MCM) Apparatus (CUMA) is a self-contained, semi-closed circuit breathing apparatus in service with the Canadian Forces (CF) and other North Atlantic Treaty Organization (NATO) Navies for MCM diving to a depth of 81 metres of seawater (msw) using a mixture of helium and oxygen. Current CF rules state that a diver completing more than 30 minutes (min) of oxygen decompression has to be accompanied by a standby diver at the 9 metre decompression stop. As there are no specific repetitive diving rules governing such shallow dives on CUMA, the procedure of adding bottom times to determine the decompression requirements of a second dive must be used. As a result, the standby diver may become unavailable for a subsequent dive to deeper depths. This affects the operational ability of a small team to continue diving as the divers, including the standby become "dived out" too quickly. Experimental dives to 9 msw to simulate a standby diver accompanying a CUMA diver were conducted in the DRDC Toronto Dive Research Facility to measure the inspired partial pressure of oxygen (PiO2). The results showed that the time-weighted average PiO2 after 30 min at 9 msw was greater than 1.3 atmospheres (absolute) (ATA). As a result, the inert gas loading should be minimal and there should be little or no decompression penalty associated with the standby diver diving again as a working CUMA diver. This will increase the operational ability of a small dive team to continue diving operations.

A massive earthquake measuring 7.0 on the moment magnitude scale shook Port-au-Prince in Haiti on 12 January 2010. Physical damage and loss of life reached cataclysmic proportions, with at least 200,000 Haitians dead, 250,000 injured, 500,000 homeless, and 300,000 buildings destroyed or condemned. The quake also closed Baie de Port-au-Prince and ruined its main pier and quay, leaving large sections submerged or damaged and severely degrading the ability to offload desperately needed supplies.

Trial Kondari was a TTCP sponsored activity to evaluate complementary harbour protection system components that could provide interdiction for underwater harbour threats, including; divers, underwater vehicles, and surface swimmers. A Command and Control (C2) centre was required to enable coordination of divers and boats, by providing a live common operating picture. The C2 centre also coordinated the logging of data for further analysis after the trial and allowed the viewing of remote displays. The design of the C2 Centre had to comply with several constraints including; short time frame, limited budget, Defence policies, and geographic distance. The solution, which will be described in this document, was cost effective, and addressed all of the requirements and constraints., The original document contains color images.

As part of the effort to characterize the acoustic and physical properties of the seafloor during the high-frequency 2004 Sediment Acoustics Experiment (SAX04), fine-scale variability of sediment sound speed and density was measured in a medium quartz sand using diver cores and an in situ conductivity probe. This study has a goal of providing environmental input to high-frequency backscatter modeling efforts. Because the experiment was conducted immediately following exposure of the site to Hurricane Ivan, measurements revealed storm-generated sedimentary structure that included mud deposits and trapped sand pockets suspended in the mud. Fluctuations of sediment sound speed and density were measured downcore at 1- and 2-cm increments, respectively, with standard laboratory techniques. Sediment density was also measured on a very fine scale with an in situ conductivity probe [in situ measurement of porosity (IMP2)] and by means of computed tomography (CT) imaging of a diver core. Overlap between the locations of the diver cores and the conductivity probe measurements allowed an examination of multiple scales of sediment heterogeneity and a comparison of techniques., Pub. in IEEE Journal of Oceanic Engineering, v35 n3 p471-487, Jul 2010.

Eustachian tube dysfunction (ETD) is associated with middle-ear barotraumas, which is one of the most prevalent medical complications in diving, aviation forces, and hyperbaric medicine. The purpose of this trial was to determine the efficacy of various drugs to decrease the incidence of ETD. Acetylcysteine, surfactant, pseudoephedrine, and oxymetazoline were tested against nasal saline mist in a subject-blinded, randomized trial. Divers were administered the drugs just prior to repetitive bounce dives while breathing oxygen or air in separate trials. Effectiveness was assessed via subjective difficulty to clear (holds on descent), ET opening pressures, and measurements elicited from a 9-step inflation/deflation tympanogram. There was considerable variability in the outcomes of each analysis that resulted in no consistent differences being established between the drugs evaluated. No drug had evidence to support recommendations for or against its use in preventing ETD. Some of the drugs tested may yet show beneficence if evaluated in another experiment designed to address the confounding factors encountered during this study., The original document contains color images.

Applications of a simple underwater imaging model (SUIM) are presented, which help to identify limiting factors in conventional underwater imaging applications, such as diver visibility. The model includes the effects of scattering caused by particles as well as turbulent flow structure. The effect of path radiance is also discussed., Presented at the International Conference on Current Problems in Optics of Natural Waters (ONW'2009), held in St. Petersburg, Russia, on 8-11 Sep 2009.

The U.S. Navy Diver's Air Sampling Program coordinates the mandatory semiannual air purity testing of compressors used to supply diver's air in the Fleet. Gas sampling kits are sent to the field, where gas samples are taken. These samples are then returned to a contract laboratory for analysis, with the results subsequently reported back to the field. This approach is expensive, cumbersome, and potentially unreliable. Consequently, the U.S. Navy is interested in having a real-time online air quality monitor to ensure that compressors deliver safe diving air. With the help of the manufacturer, Navy Experimental Diving Unit has developed and extensively tested an online air quality monitor (Anagas Diveair2, model DV 2.0, Geotechnical Instruments, Inc.; Leamington Spa, UK) for compressors supplying diving air for U.S. Navy operations. This monitor simultaneously displays levels of O2, CO2, CO, and volatile organic compounds, and it has many features designed specifically for the Navy: (1) an internal gas pump, (2) visual alarms, (3) datalogging capability, (4) a push-button program to automatically record peak gas values during testing, (5) temperature compensation of gas readings, and (6) passcode protection for calibration and other functions. The final version Diveair2 that we have tested should allow reliable real-time screening of diving air - provided that any hardware and procedures adopted for use in the field are verified to produce acceptable results., Task No. TA-05-14.

Harbor surveillance above and below the sea surface depends on sensors such as surveillance radar and multibeam sonar. These sensors attempt to detect and track moderately observable targets such as small boats or human divers in environments which often are characterized by heavy-tailed backgrounds. Target tracking in heavy-tailed environments is challenging even for moderately strong targets due to the more frequent occurrences of target-like outliers. One strategy for increased robustness is to use the backscattered signal strengths together with the kinematic measurements in the tracking method. This paper proposes two new amplitude likelihoods for target tracking in heavytailed backgrounds. The first likelihood works by incorporating the uncertainty of the background estimate. The second likelihood explicitly treats the background as heavytailed using the K-distribution., See also ADM002299. Presented at the International Conference on Information Fusion (12th) (Fusion 2009). Held in Seattle, Washington, on 6-9 July 2009. U.S. Government or Federal Rights License.. The original document contains color images.

The physical and biological characteristics of the areas inhabited by deep diving odontocetes are poorly understood. Our long term goals are: i) to measure and characterize the biomass in areas and at depths inhabited by beaked and sperm whales; ii) to measure and characterize the physics of these environments; iii) to assemble the characteristics measured (i) and (ii) into a depth integrated, 3-dimensional habitat model; the model will include other dependent and independent data, e.g., chlorophyll and depth, respectively. Our final long term goal is to then apply the habitat model produced to other geographic areas to assess their likelihood as beaked and sperm whale habitat.

The Maritime Force Protection Technology Demonstration Project (MFP TDP) is on-going at DRDC Atlantic with the objective of providing advice to the CF on force protection issues by examining requirements, state-of-the-art solutions and capability gaps, while conducting a series of tests and evaluations on developmental and COTS equipment. The Underwater Threats (UW) Component focuses on addressing deficiencies in current CF capabilities for countering underwater threats to Canadian ships in harbours and anchorages. The UW Component program is designed as a series of three Builds, each including a trial, incorporating incremental improvements using a spiral development approach. The first Build trial was completed at CFB Shearwater, Fleet Diving Unit (Atlantic), in October 2008. This was the first field test of an integrated capability that includes a QinetiQ Cerberus diver detection sonar (DDS) purchased as part of the project, and a response boat outfitted with a tactical navigation display and high frequency identification sonar for investigating targets tracked by the DDS. A major accomplishment during the trial was achievement of complete detect-to-reacquire sequences where a target was tracked by the DDS, the track location was transferred to the response boat tactical display via wireless network, and that target was reacquired with the response boat identification sonar. During exercises with divers, an underwater loud hailer was deployed after contact acquisition, a warning was issued and diver response observed. A comprehensive acoustic environmental data set was obtained during the trial which will allow further development of a DDS performance prediction tool which is also a component of the integrated capability under development., Prepared in collaboration with MacDonald Dettwiler & Assoc.. The original document contains color images.

Diver visibility has been one of the key research areas in underwater vision and imaging studies. Its applications also extend into imaging system performance evaluation and prediction, which is important in MIW and ASW operations. These applications are often associated with coastal ocean waters, and this is generally translated directly into turbidity of the water column. While mostly this is the case, exceptions can lead to erroneous predictions and potentially significant consequences. We examine issues associated with such situations, both by model as well as field data, in order to reach better estimates and to explore means to compensate for such effects, to enhance diver visibility. Visibility data collected by Navy divers from clean and relatively calm waters outside Pensacola, during Sept 2001 Gorging Littoral Ocean for Warfighters (GLOW) experiments suggested a closer examination is warranted, as observed diver visibility measured at different spatial frequencies contradicts conventional model predictions. Observation data from two different days, by different divers at different depths were used. The modulation transfer of high frequency components disappears at a level much higher than those predicted by the human vision sensitivity level. Such contradictions can be resolved, once the effect of the turbulence scattering is considered using a general imaging model., Published in the Proceedings of SPIE v7317.

SAUVIM (Semi Autonomous Underwater Vehicle for Intervention Missions) involves the design and fabrication of an underwater vehicle that it is capable of autonomous interventions on the subsea installations, a task usually carried out by ROVs or human divers., The original document contains color images.

A technical summary of work completed under contract N00014-06-1-0299, entitled "Human Bioresponse to Low-Frequency Underwater Sound," is given. Preliminary research such as the development of two micromechanical models of lung tissue and the calculation of elastic constants based upon such models is described. Progress made in the development of a lumped-element model of the human body and its internal organs is discussed. Master's theses completed under this contract are attached. The results obtained in this investigation may be useful for the determination of non-lethal sound pressure levels in a low-frequency underwater diver deterrence system., Document includes copies of two Master's Theses: "Whole-Body Vibration of Humans Due to a Low-Frequency Underwater Sound Field" and "Two-Dimensional Microscopic Model of Lung Tissue Response to Acoustic Excitation."

Navy Experimental Diving Unit (NEDU) uses cycle ergometers to increase diver oxygen consumption in many different experiments. An ongoing problem has been that, although the power requirement of cycling in the water is known to be greater than that in air for the same ergometer setting, the magnitude of the difference, particularly with diver thermal dress, has been unclear. We compared oxygen consumption during dry ergometry to that during ergometry in head-out water immersion among a total of 25 cycling subjects who wore PT gear, wet suits, dry suits, or non-return valve (NRV) suits. We also measured the effects of pedal cadence with different diver dress. Additional power varied greatly among subjects and was either independent of ergometer setting or increased with setting. Mean additional power when constant with increased ergometer setting was 64 (standard error [SE] 5) W, 69 (SE 5) W, (SE 9) W, and 126 (SE 7) W at 60 rpm in PT gear, wet suit, dry suit, and NRV suit, respectively. Additional power requirements varied approximately with the cube of cadence, a variation suggesting drag and moment of inertia, not additional torque, as the causes. Additional power in a wet suit was no different from that in PT gear. Greater pedal drag and less stable subject position may cause a greater additional power requirement at NEDU than that measured at other institutions. High intersubject variations mean that a direct measure of oxygen consumption is necessary, if that variable must be controlled.

Broad Agency Announcement Number 06-19 allowed for Wicab Inc. to develop a Tactical Underwater Navigation System (TUNS). The scope of this project is to develop a 1-inch square, thin module to be worn on the tongue, providing tactile information to the wearer via electrical stimulation of a high density matrix of electrodes embedded in the module. The tongue module can be programmed and used by divers (PJ's) or pilots to provide orientation cues when visibility is degraded or absent. It is less bulky than the current display technology (computers and handheld devices), reducing the burden, and allowing the warfighter more "hands free" mobility. The TUNS device has the potential to save lives in certain situations, where visibility is limited and time is of the essence.