Amphibious NDT Robots

Oil, petrochemical, and food processing industries worldwide store their raw materials and product in tens of thousands of storage tanks. The tanks are mostly constructed using welded steel plates and therefore subject to corrosion and weld cracking. Testing the structural integrity of these storage tanks with non-destructive testing (NDT) techniques is an expensive and time consuming activity. The walls of a large tank can usually be tested manually (for corrosion thinning and weld defects using ultrasonic techniques) from outside the tank. Access to most areas of a wall is obtained by constructing scaffolding or abseiling down from the top. However, erecting scaffolding is expensive and the inspection is tedious and slow. These costs can be reduced and the inspection speeded up by using climbing robots that deploy ultrasonic probes with scanning arms

Multi-Epoch VLBA Observations of the Compact Wind-Collision Region in the Quadruple System Cyg OB2 #5

We present multi--epoch VLBA observations of the compact wind collision region in the Cyg OB2 #5 system. These observation confirm the arc-shaped morphology of the emission reported earlier. The total flux as a function of time is roughly constant when the source is "on", but falls below the detection limit as the wind collision region approaches periastron in its orbit around the contact binary at the center of the system. In addition, at one of the "on" epochs, the flux drops to about a fifth of its average value. We suggest that this apparent variation could result from the inhomogeneity of the wind that hides part of the flux rather than from an intrinsic variation. We measured a trigonometrical parallax, for the most compact radio emission of 0.61 $\pm$ 0.22 mas, corresponding to a distance of 1.65 $^{+0.96}_{-0.44}$ kpc, in agreement with recent trigonometrical parallaxes measured for objects in the Cygnus X complex. Using constraints on the total mass of the system and orbital parameters previously reported in the literature, we obtain two independent indirect measurements of the distance to the Cyg OB2 #5 system, both consistent with 1.3--1.4 kpc. Finally, we suggest that the companion star responsible for the wind interaction, yet undetected, is of spectral type between B0.5 to O8.Comment: manuscript format, 24 pages, 5 figures, accepted for publication in The Astrophysical Journa

PDA Depth Control of a FPSO Swimming Robot

This paper introduces a Proportional, Derivative and Adaptive (PDA) depth control method for a swimming and walking robot designed for Floating Production Storage and Offloading vessel (FPSO) inspections. The depth of the robot is controlled by adjusting the mass of the buoyancy tank on the top of the robot while keeping the overall robot volume constant, so that the robot weight is adjusted around its neutral buoyancy point. The robot can swim to a given depth in short time without too much overshoot, and maintain that depth even with the disturbance from the thrusters that drive the robot moving horizontally. The control algorithm is adaptive to varying depth to let the robot have similar dynamic performance in any depth in the tank

Design of a Climbing Robot for Inspecting Aircraft Wings and Fuselage

This paper focuses on the design of a wall climbing robot. The robot carries a Cartesian scanning arm and a payload of various non-destructive testing (NDT) sensors while walking on the topside and downside of wings and on varying surface curvatures presented by the fuselage of different types of aircraft. The robot uses pneumatic cylinders to actuate the robots motion in X and Y directions. It uses suction cups to adhere the robot to the surface. The main achievement of this robot is the capability to cope with varying surface curvature when climbing around the aircraft while carrying a payload of up to 18kg. The robot achieves this capability with sufficient flexibility in its structure, feet and suctions cups to cope with varying surface curvature while remaining rigid once the robot feet adhere to the surface. Robot rigidity ensures a stable climbing motion and the vibration free deployment of the NDT sensors

Prevalence of infection with high-risk human papillomavirus in women in Colombia

AbstractThe prevalence of human papillomavirus (HPV) infections in 2109 females inhabiting five cities of Colombia was determined. Of the 49.2% with an HPV infection, 59.8% were infected with more than one viral type. Species 7 (of the the genus Alphapapillomavirus) was associated with multiple infections. Analysis of the socio-demographic data revealed a statistically significant protective effect associated with the status of civil union (civil recognition of cohabitation without marriage), and indigenous ethnicity proved to be a risk factor for HPV infection. This is the first study comparing HPV infection among women from geographical regions of Colombia with different socio-cultural structures

Vaccination of children against COVID-19: the experience in Latin America

The Coronavirus Disease 2019 (COVID-19) caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has spread globally, becoming a long-lasting pandemic [1,2,3]. As is so often the case for infectious diseases, vulnerable communities are likely to demonstrate the worse effects and this holds true for COVID-19 in Latin America [4]. Early in the pandemic, it was believed that COVID-19 did not significantly affect children. However, since the first confirmed pediatric case of COVID-19 was reported in Shenzhen, China, many cases have been reported and studied in pediatric patients [5]. It is now known that COVID-19 can affect children of all ages [6,7,8,9]. Although in many settings children usually have a lower risk of exposure and are tested less frequently than adults, the incidence in some countries in children is similar to that in adults [10]

Amphibious Robot For Weld Inspection Inside Floating Production Oil Storage Tanks

An amphibious and mobile robotic inspection system is described that has been developed to test welds located inside a floating production storage oil tank (FPSO tank). The robot has been designed to operate both in air and while submerged in oil to test welds on structural strengthening plates and tank walls. It operates in air when the tank has been emptied with only a few inches of product remaining on the floor. In this case the robot moves on the floor of the tank and inspects welds on the bottom of the strengthening plates and the floor. The robot operates in a liquid by swimming down from a manhole in the roof of the tank and settling on the floor in the vicinity of a test area. In both air and liquid, ultrasonic sensors profile the surrounding strengthening plates and tank walls and guide the robot autonomously along the welds. A Cartesian scanning arm mounted on the robot scans the welds with an ACFM probe and performs non-destructive testing (NDT) after the robot has been positioned correctly

Wall Climbing And Pipe Crawler Robots For Nozzle Weld Inspection Inside Nuclear Pressure Vessels

This paper describes the design and development of a NDT robotic solution to test circumferential welds located inside pipe nozzles at a distance of 700mm from the inside walls of nuclear pressure vessels. These welds are currently inspected using very large robot arms that are taken into the containment area and assembled. This is a time consuming operation that exposes operators to radiation. A preferred solution is to develop a light weight and compact robot that can be carried into the containment area and inserted into a pressure vessel using an overhead crane. The crane is then removed and used for other tasks. The robot must then be operated to accomplish the weld inspection task in all the pipe nozzles located in the pressure vessel

Cerro Prieto cold water injection: effects on nearby production wells

The liquid-dominated Cerro Prieto geothermal field of northern Baja California, Mexico has been under commercial exploitation since 1973. During the early years of operation, all waste brines were sent to an evaporation pond built west of the production area. In 1989, cooled pond brines began to be successfully injected into the reservoir along the western boundary of the geothermal system. The injection rate varied over the years, and is at present about 20% of the total fluid extracted. As expected under the continental desert conditions prevailing in the area, the temperature and salinity of the pond brines change with the seasons, being higher during the summer and lower during the winter. The chemistry of pond brines is also affected by precipitation of silica, oxidation of H{sub 2}S and reaction with airborne clays. Several production wells in the western part of the field (CP-I area) showed beneficial effects from injection. The chemical (chloride, isotopic) and physical (enthalpy, flow rate) changes observed in producers close to the injectors are reviewed. Some wells showed steam flow increases, in others steam flow decline rates flattened. Because of their higher density, injected brines migrated downward in the reservoir and showed up in deep wells